/* This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.  */

/*
 * $FreeBSD: head/contrib/cvs/src/server.c 177402 2008-03-19 15:08:01Z obrien $
 */

#include <assert.h>
#include "cvs.h"
#include "watch.h"
#include "edit.h"
#include "fileattr.h"
#include "getline.h"
#include "buffer.h"

int server_active = 0;

#if defined(SERVER_SUPPORT) || defined(CLIENT_SUPPORT)
# ifdef HAVE_GSSAPI
/* This stuff isn't included solely with SERVER_SUPPORT since some of these
 * functions (encryption & the like) get compiled with or without server
 * support.
 *
 * FIXME - They should be in a different file.
 */
#   include <netdb.h>
#   include "xgssapi.h"
/* We use Kerberos 5 routines to map the GSSAPI credential to a user
   name.  */
#   include <krb5.h>

/* We need this to wrap data.  */
static gss_ctx_id_t gcontext;

static void gserver_authenticate_connection PROTO((void));

/* Whether we are already wrapping GSSAPI communication.  */
static int cvs_gssapi_wrapping;

#   ifdef ENCRYPTION
/* Whether to encrypt GSSAPI communication.  We use a global variable
   like this because we use the same buffer type (gssapi_wrap) to
   handle both authentication and encryption, and we don't want
   multiple instances of that buffer in the communication stream.  */
int cvs_gssapi_encrypt;
#   endif
# endif	/* HAVE_GSSAPI */
#endif	/* defined(SERVER_SUPPORT) || defined(CLIENT_SUPPORT) */

#ifdef SERVER_SUPPORT

#ifdef HAVE_WINSOCK_H
#include <winsock.h>
#endif

#if defined (AUTH_SERVER_SUPPORT) || defined (HAVE_KERBEROS) || defined (HAVE_GSSAPI)
#include <sys/socket.h>
#endif

#ifdef HAVE_SYSLOG_H
# include <syslog.h>
# ifndef LOG_DAEMON   /* for ancient syslogs */
#  define LOG_DAEMON 0
# endif
#endif

#ifdef HAVE_KERBEROS
# include <netinet/in.h>
# include <krb.h>
# ifndef HAVE_KRB_GET_ERR_TEXT
#   define krb_get_err_text(status) krb_err_txt[status]
# endif

/* Information we need if we are going to use Kerberos encryption.  */
static C_Block kblock;
static Key_schedule sched;

#endif

/* for select */
#include "xselect.h"

#ifndef O_NONBLOCK
#define O_NONBLOCK O_NDELAY
#endif

/* EWOULDBLOCK is not defined by POSIX, but some BSD systems will
   return it, rather than EAGAIN, for nonblocking writes.  */
#ifdef EWOULDBLOCK
#define blocking_error(err) ((err) == EWOULDBLOCK || (err) == EAGAIN)
#else
#define blocking_error(err) ((err) == EAGAIN)
#endif

/* For initgroups().  */
#if HAVE_INITGROUPS
#include <grp.h>
#endif /* HAVE_INITGROUPS */

# ifdef AUTH_SERVER_SUPPORT

#   ifdef HAVE_GETSPNAM
#     include <shadow.h>
#   endif

/* The cvs username sent by the client, which might or might not be
   the same as the system username the server eventually switches to
   run as.  CVS_Username gets set iff password authentication is
   successful. */
char *CVS_Username = NULL;

/* Used to check that same repos is transmitted in pserver auth and in
   later CVS protocol.  Exported because root.c also uses. */
static char *Pserver_Repos = NULL;

/* Should we check for system usernames/passwords?  Can be changed by
   CVSROOT/config.  */
int system_auth = 1;

# endif /* AUTH_SERVER_SUPPORT */


/* While processing requests, this buffer accumulates data to be sent to
   the client, and then once we are in do_cvs_command, we use it
   for all the data to be sent.  */
static struct buffer *buf_to_net;

/* This buffer is used to read input from the client.  */
static struct buffer *buf_from_net;

/*
 * This is where we stash stuff we are going to use.  Format string
 * which expects a single directory within it, starting with a slash.
 */
static char *server_temp_dir;

/* This is the original value of server_temp_dir, before any possible
   changes inserted by serve_max_dotdot.  */
static char *orig_server_temp_dir;

/* Nonzero if we should keep the temp directory around after we exit.  */
static int dont_delete_temp;

static void server_write_entries PROTO((void));

/* All server communication goes through buffer structures.  Most of
   the buffers are built on top of a file descriptor.  This structure
   is used as the closure field in a buffer.  */

struct fd_buffer
{
    /* The file descriptor.  */
    int fd;
    /* Nonzero if the file descriptor is in blocking mode.  */
    int blocking;
};

static struct buffer *fd_buffer_initialize
  PROTO ((int, int, void (*) (struct buffer *)));
static int fd_buffer_input PROTO((void *, char *, int, int, int *));
static int fd_buffer_output PROTO((void *, const char *, int, int *));
static int fd_buffer_flush PROTO((void *));
static int fd_buffer_block PROTO((void *, int));
static int fd_buffer_shutdown PROTO((struct buffer *));

/* Initialize a buffer built on a file descriptor.  FD is the file
   descriptor.  INPUT is nonzero if this is for input, zero if this is
   for output.  MEMORY is the function to call when a memory error
   occurs.  */

static struct buffer *
fd_buffer_initialize (fd, input, memory)
     int fd;
     int input;
     void (*memory) PROTO((struct buffer *));
{
    struct fd_buffer *n;

    n = (struct fd_buffer *) xmalloc (sizeof *n);
    n->fd = fd;
    n->blocking = 1;
    return buf_initialize (input ? fd_buffer_input : NULL,
			   input ? NULL : fd_buffer_output,
			   input ? NULL : fd_buffer_flush,
			   fd_buffer_block,
			   fd_buffer_shutdown,
			   memory,
			   n);
}

/* The buffer input function for a buffer built on a file descriptor.  */

static int
fd_buffer_input (closure, data, need, size, got)
     void *closure;
     char *data;
     int need;
     int size;
     int *got;
{
    struct fd_buffer *fd = (struct fd_buffer *) closure;
    int nbytes;

    if (! fd->blocking)
	nbytes = read (fd->fd, data, size);
    else
    {
	/* This case is not efficient.  Fortunately, I don't think it
	   ever actually happens.  */
	nbytes = read (fd->fd, data, need == 0 ? 1 : need);
    }

    if (nbytes > 0)
    {
	*got = nbytes;
	return 0;
    }

    *got = 0;

    if (nbytes == 0)
    {
	/* End of file.  This assumes that we are using POSIX or BSD
	   style nonblocking I/O.  On System V we will get a zero
	   return if there is no data, even when not at EOF.  */
	return -1;
    }

    /* Some error occurred.  */

    if (blocking_error (errno))
    {
	/* Everything's fine, we just didn't get any data.  */
	return 0;
    }

    return errno;
}

/* The buffer output function for a buffer built on a file descriptor.  */

static int
fd_buffer_output (closure, data, have, wrote)
     void *closure;
     const char *data;
     int have;
     int *wrote;
{
    struct fd_buffer *fd = (struct fd_buffer *) closure;

    *wrote = 0;

    while (have > 0)
    {
	int nbytes;

	nbytes = write (fd->fd, data, have);

	if (nbytes <= 0)
	{
	    if (! fd->blocking
		&& (nbytes == 0 || blocking_error (errno)))
	    {
		/* A nonblocking write failed to write any data.  Just
		   return.  */
		return 0;
	    }

	    /* Some sort of error occurred.  */

	    if (nbytes == 0)
		return EIO;

	    return errno;
	}

	*wrote += nbytes;
	data += nbytes;
	have -= nbytes;
    }

    return 0;
}

/* The buffer flush function for a buffer built on a file descriptor.  */

/*ARGSUSED*/
static int
fd_buffer_flush (closure)
     void *closure;
{
    /* Nothing to do.  File descriptors are always flushed.  */
    return 0;
}

/* The buffer block function for a buffer built on a file descriptor.  */

static int
fd_buffer_block (closure, block)
     void *closure;
     int block;
{
    struct fd_buffer *fd = (struct fd_buffer *) closure;
    int flags;

    flags = fcntl (fd->fd, F_GETFL, 0);
    if (flags < 0)
	return errno;

    if (block)
	flags &= ~O_NONBLOCK;
    else
	flags |= O_NONBLOCK;

    if (fcntl (fd->fd, F_SETFL, flags) < 0)
	return errno;

    fd->blocking = block;

    return 0;
}

/* The buffer shutdown function for a buffer built on a file descriptor.  */

static int
fd_buffer_shutdown (buf)
     struct buffer *buf;
{
    free (buf->closure);
    buf->closure = NULL;
    return 0;
}

/* Populate all of the directories between BASE_DIR and its relative
   subdirectory DIR with CVSADM directories.  Return 0 for success or
   errno value.  */
static int create_adm_p PROTO((char *, char *));

static int
create_adm_p (base_dir, dir)
    char *base_dir;
    char *dir;
{
    char *dir_where_cvsadm_lives, *dir_to_register, *p, *tmp;
    int retval, done;
    FILE *f;

    if (strcmp (dir, ".") == 0)
	return 0;			/* nothing to do */

    /* Allocate some space for our directory-munging string. */
    p = xmalloc (strlen (dir) + 1);
    if (p == NULL)
	return ENOMEM;

    dir_where_cvsadm_lives = xmalloc (strlen (base_dir) + strlen (dir) + 100);
    if (dir_where_cvsadm_lives == NULL)
    {
	free (p);
	return ENOMEM;
    }

    /* Allocate some space for the temporary string in which we will
       construct filenames. */
    tmp = xmalloc (strlen (base_dir) + strlen (dir) + 100);
    if (tmp == NULL)
    {
	free (p);
	free (dir_where_cvsadm_lives);
	return ENOMEM;
    }


    /* We make several passes through this loop.  On the first pass,
       we simply create the CVSADM directory in the deepest directory.
       For each subsequent pass, we try to remove the last path
       element from DIR, create the CVSADM directory in the remaining
       pathname, and register the subdirectory in the newly created
       CVSADM directory. */

    retval = done = 0;

    strcpy (p, dir);
    strcpy (dir_where_cvsadm_lives, base_dir);
    strcat (dir_where_cvsadm_lives, "/");
    strcat (dir_where_cvsadm_lives, p);
    dir_to_register = NULL;

    while (1)
    {
	/* Create CVSADM. */
	(void) sprintf (tmp, "%s/%s", dir_where_cvsadm_lives, CVSADM);
	if ((CVS_MKDIR (tmp, 0777) < 0) && (errno != EEXIST))
	{
	    retval = errno;
	    goto finish;
	}

	/* Create CVSADM_REP. */
	(void) sprintf (tmp, "%s/%s", dir_where_cvsadm_lives, CVSADM_REP);
	if (! isfile (tmp))
	{
	    /* Use Emptydir as the placeholder until the client sends
	       us the real value.  This code is similar to checkout.c
	       (emptydir_name), but the code below returns errors
	       differently.  */

	    char *empty;
	    empty = xmalloc (strlen (current_parsed_root->directory)
			    + sizeof (CVSROOTADM)
			    + sizeof (CVSNULLREPOS)
			    + 3);
	    if (! empty)
	    {
		retval = ENOMEM;
		goto finish;
	    }

	    /* Create the directory name. */
	    (void) sprintf (empty, "%s/%s/%s", current_parsed_root->directory,
			    CVSROOTADM, CVSNULLREPOS);

	    /* Create the directory if it doesn't exist. */
	    if (! isfile (empty))
	    {
		mode_t omask;
		omask = umask (cvsumask);
		if (CVS_MKDIR (empty, 0777) < 0)
		{
		    retval = errno;
		    free (empty);
		    goto finish;
		}
		(void) umask (omask);
	    }

	    f = CVS_FOPEN (tmp, "w");
	    if (f == NULL)
	    {
		retval = errno;
		free (empty);
		goto finish;
	    }
	    /* Write the directory name to CVSADM_REP. */
	    if (fprintf (f, "%s\n", empty) < 0)
	    {
		retval = errno;
		fclose (f);
		free (empty);
		goto finish;
	    }
	    if (fclose (f) == EOF)
	    {
		retval = errno;
		free (empty);
		goto finish;
	    }

	    /* Clean up after ourselves. */
	    free (empty);
	}

	/* Create CVSADM_ENT.  We open in append mode because we
	   don't want to clobber an existing Entries file.  */
	(void) sprintf (tmp, "%s/%s", dir_where_cvsadm_lives, CVSADM_ENT);
	f = CVS_FOPEN (tmp, "a");
	if (f == NULL)
	{
	    retval = errno;
	    goto finish;
	}
	if (fclose (f) == EOF)
	{
	    retval = errno;
	    goto finish;
	}

	if (dir_to_register != NULL)
	{
	    /* FIXME: Yes, this results in duplicate entries in the
	       Entries.Log file, but it doesn't currently matter.  We
	       might need to change this later on to make sure that we
	       only write one entry.  */

	    Subdir_Register ((List *) NULL, dir_where_cvsadm_lives,
			     dir_to_register);
	}

	if (done)
	    break;

	dir_to_register = strrchr (p, '/');
	if (dir_to_register == NULL)
	{
	    dir_to_register = p;
	    strcpy (dir_where_cvsadm_lives, base_dir);
	    done = 1;
	}
	else
	{
	    *dir_to_register = '\0';
	    dir_to_register++;
	    strcpy (dir_where_cvsadm_lives, base_dir);
	    strcat (dir_where_cvsadm_lives, "/");
	    strcat (dir_where_cvsadm_lives, p);
	}
    }

  finish:
    free (tmp);
    free (dir_where_cvsadm_lives);
    free (p);
    return retval;
}

/*
 * Make directory DIR, including all intermediate directories if necessary.
 * Returns 0 for success or errno code.
 */
static int mkdir_p PROTO((char *));

static int
mkdir_p (dir)
     char *dir;
{
    char *p;
    char *q = xmalloc (strlen (dir) + 1);
    int retval;

    if (q == NULL)
	return ENOMEM;

    retval = 0;

    /*
     * Skip over leading slash if present.  We won't bother to try to
     * make '/'.
     */
    p = dir + 1;
    while (1)
    {
	while (*p != '/' && *p != '\0')
	    ++p;
	if (*p == '/')
	{
	    strncpy (q, dir, p - dir);
	    q[p - dir] = '\0';
	    if (q[p - dir - 1] != '/'  &&  CVS_MKDIR (q, 0777) < 0)
	    {
		int saved_errno = errno;

		if (saved_errno != EEXIST
		    && ((saved_errno != EACCES && saved_errno != EROFS)
			|| !isdir (q)))
		{
		    retval = saved_errno;
		    goto done;
		}
	    }
	    ++p;
	}
	else
	{
	    if (CVS_MKDIR (dir, 0777) < 0)
		retval = errno;
	    goto done;
	}
    }
  done:
    free (q);
    return retval;
}

/*
 * Print the error response for error code STATUS.  The caller is
 * reponsible for making sure we get back to the command loop without
 * any further output occuring.
 * Must be called only in contexts where it is OK to send output.
 */
static void
print_error (status)
    int status;
{
    char *msg;
    char tmpstr[80];

    buf_output0 (buf_to_net, "error  ");
    msg = strerror (status);
    if (msg == NULL)
    {
       sprintf (tmpstr, "unknown error %d", status);
       msg = tmpstr;
    }
    buf_output0 (buf_to_net, msg);
    buf_append_char (buf_to_net, '\n');

    buf_flush (buf_to_net, 0);
}

static int pending_error;
/*
 * Malloc'd text for pending error.  Each line must start with "E ".  The
 * last line should not end with a newline.
 */
static char *pending_error_text;

/* If an error is pending, print it and return 1.  If not, return 0.
   Must be called only in contexts where it is OK to send output.  */
static int
print_pending_error ()
{
    if (pending_error_text)
    {
	buf_output0 (buf_to_net, pending_error_text);
	buf_append_char (buf_to_net, '\n');
	if (pending_error)
	    print_error (pending_error);
	else
	    buf_output0 (buf_to_net, "error  \n");

	buf_flush (buf_to_net, 0);

	pending_error = 0;
	free (pending_error_text);
	pending_error_text = NULL;
	return 1;
    }
    else if (pending_error)
    {
	print_error (pending_error);
	pending_error = 0;
	return 1;
    }
    else
	return 0;
}

/* Is an error pending?  */
#define error_pending() (pending_error || pending_error_text)

static int alloc_pending PROTO ((size_t size));

/* Allocate SIZE bytes for pending_error_text and return nonzero
   if we could do it.  */
static int
alloc_pending (size)
    size_t size;
{
    if (error_pending ())
	/* Probably alloc_pending callers will have already checked for
	   this case.  But we might as well handle it if they don't, I
	   guess.  */
	return 0;
    pending_error_text = xmalloc (size);
    if (pending_error_text == NULL)
    {
	pending_error = ENOMEM;
	return 0;
    }
    return 1;
}

static void serve_is_modified PROTO ((char *));

static int supported_response PROTO ((char *));

static int
supported_response (name)
     char *name;
{
    struct response *rs;

    for (rs = responses; rs->name != NULL; ++rs)
	if (strcmp (rs->name, name) == 0)
	    return rs->status == rs_supported;
    error (1, 0, "internal error: testing support for unknown response?");
    /* NOTREACHED */
    return 0;
}

static void
serve_valid_responses (arg)
     char *arg;
{
    char *p = arg;
    char *q;
    struct response *rs;
    do
    {
	q = strchr (p, ' ');
	if (q != NULL)
	    *q++ = '\0';
	for (rs = responses; rs->name != NULL; ++rs)
	{
	    if (strcmp (rs->name, p) == 0)
		break;
	}
	if (rs->name == NULL)
	    /*
	     * It is a response we have never heard of (and thus never
	     * will want to use).  So don't worry about it.
	     */
	    ;
	else
	    rs->status = rs_supported;
	p = q;
    } while (q != NULL);
    for (rs = responses; rs->name != NULL; ++rs)
    {
	if (rs->status == rs_essential)
	{
	    buf_output0 (buf_to_net, "E response `");
	    buf_output0 (buf_to_net, rs->name);
	    buf_output0 (buf_to_net, "' not supported by client\nerror  \n");

	    /* FIXME: This call to buf_flush could conceivably
	       cause deadlock, as noted in server_cleanup.  */
	    buf_flush (buf_to_net, 1);

	    error_exit ();
	}
	else if (rs->status == rs_optional)
	    rs->status = rs_not_supported;
    }
}

static void
serve_root (arg)
    char *arg;
{
    char *env;
    char *path;

    if (error_pending()) return;

    if (!isabsolute (arg))
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text,
		     "E Root %s must be an absolute pathname", arg);
	return;
    }

    /* Sending "Root" twice is illegal.

       The other way to handle a duplicate Root requests would be as a
       request to clear out all state and start over as if it was a
       new connection.  Doing this would cause interoperability
       headaches, so it should be a different request, if there is
       any reason why such a feature is needed.  */
    if (current_parsed_root != NULL)
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text,
		     "E Protocol error: Duplicate Root request, for %s", arg);
	return;
    }

    /* We need to check :ext: server here, :pserver: checks happen below. */
    if (root_allow_used() && !root_allow_ok (arg)
# ifdef AUTH_SERVER_SUPPORT
	&& Pserver_Repos == NULL
# endif
	)
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text,
		     "E Bad root %s", arg);
	return;
    }

#ifdef AUTH_SERVER_SUPPORT
    if (Pserver_Repos != NULL)
    {
	if (strcmp (Pserver_Repos, arg) != 0)
	{
	    if (alloc_pending (80 + strlen (Pserver_Repos) + strlen (arg)))
		/* The explicitness is to aid people who are writing clients.
		   I don't see how this information could help an
		   attacker.  */
		sprintf (pending_error_text, "\
E Protocol error: Root says \"%s\" but pserver says \"%s\"",
			 arg, Pserver_Repos);
	    return;
	}
    }
#endif

    current_parsed_root = local_cvsroot (arg);

    /* For pserver, this will already have happened, and the call will do
       nothing.  But for rsh, we need to do it now.  */
    parse_config (current_parsed_root->directory);

    /* Now is a good time to read CVSROOT/options too. */
    parseopts(current_parsed_root->directory);

    path = xmalloc (strlen (current_parsed_root->directory)
		   + sizeof (CVSROOTADM)
		   + 2);
    if (path == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    (void) sprintf (path, "%s/%s", current_parsed_root->directory, CVSROOTADM);
    if (!isaccessible (path, R_OK | X_OK))
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (path)))
	    sprintf (pending_error_text, "E Cannot access %s", path);
	pending_error = save_errno;
    }
    free (path);

#ifdef HAVE_PUTENV
    env = xmalloc (strlen (CVSROOT_ENV) + strlen (current_parsed_root->directory) + 2);
    if (env == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    (void) sprintf (env, "%s=%s", CVSROOT_ENV, current_parsed_root->directory);
    (void) putenv (env);
    /* do not free env, as putenv has control of it */
#endif
}

static int max_dotdot_limit = 0;

/* Is this pathname OK to recurse into when we are running as the server?
   If not, call error() with a fatal error.  */
void
server_pathname_check (path)
    char *path;
{
    /* An absolute pathname is almost surely a path on the *client* machine,
       and is unlikely to do us any good here.  It also is probably capable
       of being a security hole in the anonymous readonly case.  */
    if (isabsolute (path))
	/* Giving an error is actually kind of a cop-out, in the sense
	   that it would be nice for "cvs co -d /foo/bar/baz" to work.
	   A quick fix in the server would be requiring Max-dotdot of
	   at least one if pathnames are absolute, and then putting
	   /abs/foo/bar/baz in the temp dir beside the /d/d/d stuff.
	   A cleaner fix in the server might be to decouple the
	   pathnames we pass back to the client from pathnames in our
	   temp directory (this would also probably remove the need
	   for Max-dotdot).  A fix in the client would have the client
	   turn it into "cd /foo/bar; cvs co -d baz" (more or less).
	   This probably has some problems with pathnames which appear
	   in messages.  */
	error (1, 0, "absolute pathname `%s' illegal for server", path);
    if (pathname_levels (path) > max_dotdot_limit)
    {
	/* Similar to the isabsolute case in security implications.  */
	error (0, 0, "protocol error: `%s' contains more leading ..", path);
	error (1, 0, "than the %d which Max-dotdot specified",
	       max_dotdot_limit);
    }
}

static int outside_root PROTO ((char *));

/* Is file or directory REPOS an absolute pathname within the
   current_parsed_root->directory?  If yes, return 0.  If no, set pending_error
   and return 1.  */
static int
outside_root (repos)
    char *repos;
{
    size_t repos_len = strlen (repos);
    size_t root_len = strlen (current_parsed_root->directory);

    /* isabsolute (repos) should always be true, but
       this is a good security precaution regardless. -DRP
     */
    if (!isabsolute (repos))
    {
	if (alloc_pending (repos_len + 80))
	    sprintf (pending_error_text, "\
E protocol error: %s is not absolute", repos);
	return 1;
    }

    if (repos_len < root_len
	|| strncmp (current_parsed_root->directory, repos, root_len) != 0)
    {
    not_within:
	if (alloc_pending (strlen (current_parsed_root->directory)
			   + strlen (repos)
			   + 80))
	    sprintf (pending_error_text, "\
E protocol error: directory '%s' not within root '%s'",
		     repos, current_parsed_root->directory);
	return 1;
    }
    if (repos_len > root_len)
    {
	if (repos[root_len] != '/')
	    goto not_within;
	if (pathname_levels (repos + root_len + 1) > 0)
	    goto not_within;
    }
    return 0;
}

static int outside_dir PROTO ((char *));

/* Is file or directory FILE outside the current directory (that is, does
   it contain '/')?  If no, return 0.  If yes, set pending_error
   and return 1.  */
static int
outside_dir (file)
    char *file;
{
    if (strchr (file, '/') != NULL)
    {
	if (alloc_pending (strlen (file)
			   + 80))
	    sprintf (pending_error_text, "\
E protocol error: directory '%s' not within current directory",
		     file);
	return 1;
    }
    return 0;
}

/*
 * Add as many directories to the temp directory as the client tells us it
 * will use "..", so we never try to access something outside the temp
 * directory via "..".
 */
static void
serve_max_dotdot (arg)
    char *arg;
{
    int lim = atoi (arg);
    int i;
    char *p;

    if (lim < 0 || lim > 10000)
	return;
    p = xmalloc (strlen (server_temp_dir) + 2 * lim + 10);
    if (p == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    strcpy (p, server_temp_dir);
    for (i = 0; i < lim; ++i)
	strcat (p, "/d");
    if (server_temp_dir != orig_server_temp_dir)
	free (server_temp_dir);
    server_temp_dir = p;
    max_dotdot_limit = lim;
}

static char *dir_name;

static void
dirswitch (dir, repos)
    char *dir;
    char *repos;
{
    int status;
    FILE *f;
    size_t dir_len;

    server_write_entries ();

    if (error_pending()) return;

    /* Check for bad directory name.

       FIXME: could/should unify these checks with server_pathname_check
       except they need to report errors differently.  */
    if (isabsolute (dir))
    {
	if (alloc_pending (80 + strlen (dir)))
	    sprintf (pending_error_text,
		     "E absolute pathname `%s' illegal for server", dir);
	return;
    }
    if (pathname_levels (dir) > max_dotdot_limit)
    {
	if (alloc_pending (80 + strlen (dir)))
	    sprintf (pending_error_text,
		     "E protocol error: `%s' has too many ..", dir);
	return;
    }

    dir_len = strlen (dir);

    /* Check for a trailing '/'.  This is not ISDIRSEP because \ in the
       protocol is an ordinary character, not a directory separator (of
       course, it is perhaps unwise to use it in directory names, but that
       is another issue).  */
    if (dir_len > 0
	&& dir[dir_len - 1] == '/')
    {
	if (alloc_pending (80 + dir_len))
	    sprintf (pending_error_text,
		     "E protocol error: invalid directory syntax in %s", dir);
	return;
    }

    if (dir_name != NULL)
	free (dir_name);

    dir_name = xmalloc (strlen (server_temp_dir) + dir_len + 40);
    if (dir_name == NULL)
    {
	pending_error = ENOMEM;
	return;
    }

    strcpy (dir_name, server_temp_dir);
    strcat (dir_name, "/");
    strcat (dir_name, dir);

    status = mkdir_p (dir_name);
    if (status != 0
	&& status != EEXIST)
    {
	if (alloc_pending (80 + strlen (dir_name)))
	    sprintf (pending_error_text, "E cannot mkdir %s", dir_name);
	pending_error = status;
	return;
    }

    /* We need to create adm directories in all path elements because
       we want the server to descend them, even if the client hasn't
       sent the appropriate "Argument xxx" command to match the
       already-sent "Directory xxx" command.  See recurse.c
       (start_recursion) for a big discussion of this.  */

    status = create_adm_p (server_temp_dir, dir);
    if (status != 0)
    {
	if (alloc_pending (80 + strlen (dir_name)))
	    sprintf (pending_error_text, "E cannot create_adm_p %s", dir_name);
	pending_error = status;
	return;
    }

    if ( CVS_CHDIR (dir_name) < 0)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (dir_name)))
	    sprintf (pending_error_text, "E cannot change to %s", dir_name);
	pending_error = save_errno;
	return;
    }
    /*
     * This is pretty much like calling Create_Admin, but Create_Admin doesn't
     * report errors in the right way for us.
     */
    if ((CVS_MKDIR (CVSADM, 0777) < 0) && (errno != EEXIST))
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (dir_name) + strlen (CVSADM)))
	    sprintf (pending_error_text,
		     "E cannot mkdir %s/%s", dir_name, CVSADM);
	pending_error = save_errno;
	return;
    }

    /* The following will overwrite the contents of CVSADM_REP.  This
       is the correct behavior -- mkdir_p may have written a
       placeholder value to this file and we need to insert the
       correct value. */

    f = CVS_FOPEN (CVSADM_REP, "w");
    if (f == NULL)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (dir_name) + strlen (CVSADM_REP)))
	    sprintf (pending_error_text,
		     "E cannot open %s/%s", dir_name, CVSADM_REP);
	pending_error = save_errno;
	return;
    }
    if (fprintf (f, "%s", repos) < 0)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (dir_name) + strlen (CVSADM_REP)))
	    sprintf (pending_error_text,
		     "E error writing %s/%s", dir_name, CVSADM_REP);
	pending_error = save_errno;
	fclose (f);
	return;
    }
    /* Non-remote CVS handles a module representing the entire tree
       (e.g., an entry like ``world -a .'') by putting /. at the end
       of the Repository file, so we do the same.  */
    if (strcmp (dir, ".") == 0
	&& current_parsed_root != NULL
	&& current_parsed_root->directory != NULL
	&& strcmp (current_parsed_root->directory, repos) == 0)
    {
	if (fprintf (f, "/.") < 0)
	{
	    int save_errno = errno;
	    if (alloc_pending (80 + strlen (dir_name) + strlen (CVSADM_REP)))
		sprintf (pending_error_text,
			 "E error writing %s/%s", dir_name, CVSADM_REP);
	    pending_error = save_errno;
	    fclose (f);
	    return;
	}
    }
    if (fprintf (f, "\n") < 0)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (dir_name) + strlen (CVSADM_REP)))
	    sprintf (pending_error_text,
		     "E error writing %s/%s", dir_name, CVSADM_REP);
	pending_error = save_errno;
	fclose (f);
	return;
    }
    if (fclose (f) == EOF)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (dir_name) + strlen (CVSADM_REP)))
	    sprintf (pending_error_text,
		     "E error closing %s/%s", dir_name, CVSADM_REP);
	pending_error = save_errno;
	return;
    }
    /* We open in append mode because we don't want to clobber an
       existing Entries file.  */
    f = CVS_FOPEN (CVSADM_ENT, "a");
    if (f == NULL)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_ENT)))
	    sprintf (pending_error_text, "E cannot open %s", CVSADM_ENT);
	pending_error = save_errno;
	return;
    }
    if (fclose (f) == EOF)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_ENT)))
	    sprintf (pending_error_text, "E cannot close %s", CVSADM_ENT);
	pending_error = save_errno;
	return;
    }
}

static void
serve_repository (arg)
    char *arg;
{
    if (alloc_pending (80))
	strcpy (pending_error_text,
		"E Repository request is obsolete; aborted");
    return;
}

static void
serve_directory (arg)
    char *arg;
{
    int status;
    char *repos;

    status = buf_read_line (buf_from_net, &repos, (int *) NULL);
    if (status == 0)
    {
	if (!outside_root (repos))
	    dirswitch (arg, repos);
	free (repos);
    }
    else if (status == -2)
    {
	pending_error = ENOMEM;
    }
    else
    {
	pending_error_text = xmalloc (80 + strlen (arg));
	if (pending_error_text == NULL)
	{
	    pending_error = ENOMEM;
	}
	else if (status == -1)
	{
	    sprintf (pending_error_text,
		     "E end of file reading mode for %s", arg);
	}
	else
	{
	    sprintf (pending_error_text,
		     "E error reading mode for %s", arg);
	    pending_error = status;
	}
    }
}

static void
serve_static_directory (arg)
    char *arg;
{
    FILE *f;

    if (error_pending ()) return;

    f = CVS_FOPEN (CVSADM_ENTSTAT, "w+");
    if (f == NULL)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_ENTSTAT)))
	    sprintf (pending_error_text, "E cannot open %s", CVSADM_ENTSTAT);
	pending_error = save_errno;
	return;
    }
    if (fclose (f) == EOF)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_ENTSTAT)))
	    sprintf (pending_error_text, "E cannot close %s", CVSADM_ENTSTAT);
	pending_error = save_errno;
	return;
    }
}

static void
serve_sticky (arg)
    char *arg;
{
    FILE *f;

    if (error_pending ()) return;

    f = CVS_FOPEN (CVSADM_TAG, "w+");
    if (f == NULL)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_TAG)))
	    sprintf (pending_error_text, "E cannot open %s", CVSADM_TAG);
	pending_error = save_errno;
	return;
    }
    if (fprintf (f, "%s\n", arg) < 0)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_TAG)))
	    sprintf (pending_error_text, "E cannot write to %s", CVSADM_TAG);
	pending_error = save_errno;
	(void) fclose (f);
	return;
    }
    if (fclose (f) == EOF)
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_TAG)))
	    sprintf (pending_error_text, "E cannot close %s", CVSADM_TAG);
	pending_error = save_errno;
	return;
    }
}

/*
 * Read SIZE bytes from buf_from_net, write them to FILE.
 *
 * Currently this isn't really used for receiving parts of a file --
 * the file is still sent over in one chunk.  But if/when we get
 * spiffy in-process gzip support working, perhaps the compressed
 * pieces could be sent over as they're ready, if the network is fast
 * enough.  Or something.
 */
static void
receive_partial_file (size, file)
     int size;
     int file;
{
    while (size > 0)
    {
	int status, nread;
	char *data;

	status = buf_read_data (buf_from_net, size, &data, &nread);
	if (status != 0)
	{
	    if (status == -2)
		pending_error = ENOMEM;
	    else
	    {
		pending_error_text = xmalloc (80);
		if (pending_error_text == NULL)
		    pending_error = ENOMEM;
		else if (status == -1)
		{
		    sprintf (pending_error_text,
			     "E premature end of file from client");
		    pending_error = 0;
		}
		else
		{
		    sprintf (pending_error_text,
			     "E error reading from client");
		    pending_error = status;
		}
	    }
	    return;
	}

	size -= nread;

	while (nread > 0)
	{
	    int nwrote;

	    nwrote = write (file, data, nread);
	    if (nwrote < 0)
	    {
		int save_errno = errno;
		if (alloc_pending (40))
		    strcpy (pending_error_text, "E unable to write");
		pending_error = save_errno;

		/* Read and discard the file data.  */
		while (size > 0)
		{
		    int status, nread;
		    char *data;

		    status = buf_read_data (buf_from_net, size, &data, &nread);
		    if (status != 0)
			return;
		    size -= nread;
		}

		return;
	    }
	    nread -= nwrote;
	    data += nwrote;
	}
    }
}

/* Receive SIZE bytes, write to filename FILE.  */
static void
receive_file (size, file, gzipped)
     int size;
     char *file;
     int gzipped;
{
    int fd;
    char *arg = file;

    /* Write the file.  */
    fd = CVS_OPEN (arg, O_WRONLY | O_CREAT | O_TRUNC, 0600);
    if (fd < 0)
    {
	int save_errno = errno;
	if (alloc_pending (40 + strlen (arg)))
	    sprintf (pending_error_text, "E cannot open %s", arg);
	pending_error = save_errno;
	return;
    }

    if (gzipped)
    {
	/* Using gunzip_and_write isn't really a high-performance
	   approach, because it keeps the whole thing in memory
	   (contiguous memory, worse yet).  But it seems easier to
	   code than the alternative (and less vulnerable to subtle
	   bugs).  Given that this feature is mainly for
	   compatibility, that is the better tradeoff.  */

	int toread = size;
	char *filebuf;
	char *p;

	filebuf = xmalloc (size);
	p = filebuf;
	/* If NULL, we still want to read the data and discard it.  */

	while (toread > 0)
	{
	    int status, nread;
	    char *data;

	    status = buf_read_data (buf_from_net, toread, &data, &nread);
	    if (status != 0)
	    {
		if (status == -2)
		    pending_error = ENOMEM;
		else
		{
		    pending_error_text = xmalloc (80);
		    if (pending_error_text == NULL)
			pending_error = ENOMEM;
		    else if (status == -1)
		    {
			sprintf (pending_error_text,
				 "E premature end of file from client");
			pending_error = 0;
		    }
		    else
		    {
			sprintf (pending_error_text,
				 "E error reading from client");
			pending_error = status;
		    }
		}
		return;
	    }

	    toread -= nread;

	    if (filebuf != NULL)
	    {
		memcpy (p, data, nread);
		p += nread;
	    }
	}
	if (filebuf == NULL)
	{
	    pending_error = ENOMEM;
	    goto out;
	}

	if (gunzip_and_write (fd, file, (unsigned char *) filebuf, size))
	{
	    if (alloc_pending (80))
		sprintf (pending_error_text,
			 "E aborting due to compression error");
	}
	free (filebuf);
    }
    else
	receive_partial_file (size, fd);

    if (pending_error_text)
    {
	char *p = xrealloc (pending_error_text,
			   strlen (pending_error_text) + strlen (arg) + 30);
	if (p)
	{
	    pending_error_text = p;
	    sprintf (p + strlen (p), ", file %s", arg);
	}
	/* else original string is supposed to be unchanged */
    }

 out:
    if (close (fd) < 0 && !error_pending ())
    {
	int save_errno = errno;
	if (alloc_pending (40 + strlen (arg)))
	    sprintf (pending_error_text, "E cannot close %s", arg);
	pending_error = save_errno;
	return;
    }
}

/* Kopt for the next file sent in Modified or Is-modified.  */
static char *kopt;

/* Timestamp (Checkin-time) for next file sent in Modified or
   Is-modified.  */
static int checkin_time_valid;
static time_t checkin_time;

static void serve_modified PROTO ((char *));

static void
serve_modified (arg)
     char *arg;
{
    int size, status;
    char *size_text;
    char *mode_text;

    int gzipped = 0;

    /*
     * This used to return immediately if error_pending () was true.
     * However, that fails, because it causes each line of the file to
     * be echoed back to the client as an unrecognized command.  The
     * client isn't reading from the socket, so eventually both
     * processes block trying to write to the other.  Now, we try to
     * read the file if we can.
     */

    status = buf_read_line (buf_from_net, &mode_text, (int *) NULL);
    if (status != 0)
    {
	if (status == -2)
	    pending_error = ENOMEM;
	else
	{
	    pending_error_text = xmalloc (80 + strlen (arg));
	    if (pending_error_text == NULL)
		pending_error = ENOMEM;
	    else
	    {
		if (status == -1)
		    sprintf (pending_error_text,
			     "E end of file reading mode for %s", arg);
		else
		{
		    sprintf (pending_error_text,
			     "E error reading mode for %s", arg);
		    pending_error = status;
		}
	    }
	}
	return;
    }

    status = buf_read_line (buf_from_net, &size_text, (int *) NULL);
    if (status != 0)
    {
	if (status == -2)
	    pending_error = ENOMEM;
	else
	{
	    pending_error_text = xmalloc (80 + strlen (arg));
	    if (pending_error_text == NULL)
		pending_error = ENOMEM;
	    else
	    {
		if (status == -1)
		    sprintf (pending_error_text,
			     "E end of file reading size for %s", arg);
		else
		{
		    sprintf (pending_error_text,
			     "E error reading size for %s", arg);
		    pending_error = status;
		}
	    }
	}
	free (mode_text);
	return;
    }
    if (size_text[0] == 'z')
    {
	gzipped = 1;
	size = atoi (size_text + 1);
    }
    else
	size = atoi (size_text);
    free (size_text);

    if (error_pending ())
    {
	/* Now that we know the size, read and discard the file data.  */
	while (size > 0)
	{
	    int status, nread;
	    char *data;

	    status = buf_read_data (buf_from_net, size, &data, &nread);
	    if (status != 0)
		return;
	    size -= nread;
	}
	free (mode_text);
	return;
    }

    if (outside_dir (arg))
    {
	free (mode_text);
	return;
    }

    if (size >= 0)
    {
	receive_file (size, arg, gzipped);
	if (error_pending ())
	{
	    free (mode_text);
	    return;
	}
    }

    if (checkin_time_valid)
    {
	struct utimbuf t;

	memset (&t, 0, sizeof (t));
	t.modtime = t.actime = checkin_time;
	if (utime (arg, &t) < 0)
	{
	    int save_errno = errno;
	    if (alloc_pending (80 + strlen (arg)))
		sprintf (pending_error_text, "E cannot utime %s", arg);
	    pending_error = save_errno;
	    free (mode_text);
	    return;
	}
	checkin_time_valid = 0;
    }

    {
	int status = change_mode (arg, mode_text, 0);
	free (mode_text);
	if (status)
	{
	    if (alloc_pending (40 + strlen (arg)))
		sprintf (pending_error_text,
			 "E cannot change mode for %s", arg);
	    pending_error = status;
	    return;
	}
    }

    /* Make sure that the Entries indicate the right kopt.  We probably
       could do this even in the non-kopt case and, I think, save a stat()
       call in time_stamp_server.  But for conservatism I'm leaving the
       non-kopt case alone.  */
    if (kopt != NULL)
	serve_is_modified (arg);
}


static void
serve_enable_unchanged (arg)
     char *arg;
{
}

struct an_entry {
    struct an_entry *next;
    char *entry;
};

static struct an_entry *entries;

static void serve_unchanged PROTO ((char *));

static void
serve_unchanged (arg)
    char *arg;
{
    struct an_entry *p;
    char *name;
    char *cp;
    char *timefield;

    if (error_pending ()) return;

    if (outside_dir (arg))
	return;

    /* Rewrite entries file to have `=' in timestamp field.  */
    for (p = entries; p != NULL; p = p->next)
    {
	name = p->entry + 1;
	cp = strchr (name, '/');
	if (cp != NULL
	    && strlen (arg) == cp - name
	    && strncmp (arg, name, cp - name) == 0)
	{
	    if (!(timefield = strchr (cp + 1, '/')) || *++timefield == '\0')
	    {
		/* We didn't find the record separator or it is followed by
		 * the end of the string, so just exit.
		 */
		if (alloc_pending (80))
		    sprintf (pending_error_text,
		             "E Malformed Entry encountered.");
		return;
	    }
	    /* If the time field is not currently empty, then one of
	     * serve_modified, serve_is_modified, & serve_unchanged were
	     * already called for this file.  We would like to ignore the
	     * reinvocation silently or, better yet, exit with an error
	     * message, but we just avoid the copy-forward and overwrite the
	     * value from the last invocation instead.  See the comment below
	     * for more.
	     */
	    if (*timefield == '/')
	    {
		/* Copy forward one character.  Space was allocated for this
		 * already in serve_entry().  */
		cp = timefield + strlen (timefield);
		cp[1] = '\0';
		while (cp > timefield)
		{
		    *cp = cp[-1];
		    --cp;
		}
	    }
	    /* If *TIMEFIELD wasn't "/", we assume that it was because of
	     * multiple calls to Is-Modified & Unchanged by the client and
	     * just overwrite the value from the last call.  Technically, we
	     * should probably either ignore calls after the first or send the
	     * client an error, since the client/server protocol specification
	     * specifies that only one call to either Is-Modified or Unchanged
	     * is allowed, but broken versions of WinCVS & TortoiseCVS rely on
	     * this behavior.
	     */
	    if (*timefield != '+')
		/* Skip this for entries with conflict markers.  */
		*timefield = '=';
	    break;
	}
    }
}

static void
serve_is_modified (arg)
    char *arg;
{
    struct an_entry *p;
    char *name;
    char *cp;
    char *timefield;
    /* Have we found this file in "entries" yet.  */
    int found;

    if (error_pending ()) return;

    if (outside_dir (arg))
	return;

    /* Rewrite entries file to have `M' in timestamp field.  */
    found = 0;
    for (p = entries; p != NULL; p = p->next)
    {
	name = p->entry + 1;
	cp = strchr (name, '/');
	if (cp != NULL
	    && strlen (arg) == cp - name
	    && strncmp (arg, name, cp - name) == 0)
	{
	    if (!(timefield = strchr (cp + 1, '/')) || *++timefield == '\0')
	    {
		/* We didn't find the record separator or it is followed by
		 * the end of the string, so just exit.
		 */
		if (alloc_pending (80))
		    sprintf (pending_error_text,
		             "E Malformed Entry encountered.");
		return;
	    }
	    /* If the time field is not currently empty, then one of
	     * serve_modified, serve_is_modified, & serve_unchanged were
	     * already called for this file.  We would like to ignore the
	     * reinvocation silently or, better yet, exit with an error
	     * message, but we just avoid the copy-forward and overwrite the
	     * value from the last invocation instead.  See the comment below
	     * for more.
	     */
	    if (*timefield == '/')
	    {
		/* Copy forward one character.  Space was allocated for this
		 * already in serve_entry().  */
		cp = timefield + strlen (timefield);
		cp[1] = '\0';
		while (cp > timefield)
		{
		    *cp = cp[-1];
		    --cp;
		}
	    }
	    /* If *TIMEFIELD wasn't "/", we assume that it was because of
	     * multiple calls to Is-Modified & Unchanged by the client and
	     * just overwrite the value from the last call.  Technically, we
	     * should probably either ignore calls after the first or send the
	     * client an error, since the client/server protocol specification
	     * specifies that only one call to either Is-Modified or Unchanged
	     * is allowed, but broken versions of WinCVS & TortoiseCVS rely on
	     * this behavior.
	     */
	    if (*timefield != '+')
		/* Skip this for entries with conflict markers.  */
		*timefield = 'M';

	    if (kopt != NULL)
	    {
		if (alloc_pending (strlen (name) + 80))
		    sprintf (pending_error_text,
			     "E protocol error: both Kopt and Entry for %s",
			     arg);
		free (kopt);
		kopt = NULL;
		return;
	    }
	    found = 1;
	    break;
	}
    }
    if (!found)
    {
	/* We got Is-modified but no Entry.  Add a dummy entry.
	   The "D" timestamp is what makes it a dummy.  */
	p = (struct an_entry *) xmalloc (sizeof (struct an_entry));
	if (p == NULL)
	{
	    pending_error = ENOMEM;
	    return;
	}
	p->entry = xmalloc (strlen (arg) + 80);
	if (p->entry == NULL)
	{
	    pending_error = ENOMEM;
	    free (p);
	    return;
	}
	strcpy (p->entry, "/");
	strcat (p->entry, arg);
	strcat (p->entry, "//D/");
	if (kopt != NULL)
	{
	    strcat (p->entry, kopt);
	    free (kopt);
	    kopt = NULL;
	}
	strcat (p->entry, "/");
	p->next = entries;
	entries = p;
    }
}

static void serve_entry PROTO ((char *));

static void
serve_entry (arg)
     char *arg;
{
    struct an_entry *p;
    char *cp;
    int i = 0;
    if (error_pending()) return;

    /* Verify that the entry is well-formed.  This can avoid problems later.
     * At the moment we only check that the Entry contains five slashes in
     * approximately the correct locations since some of the code makes
     * assumptions about this.
     */
    cp = arg;
    if (*cp == 'D') cp++;
    while (i++ < 5)
    {
	if (!cp || *cp != '/')
	{
	    if (alloc_pending (80))
		sprintf (pending_error_text,
			 "E protocol error: Malformed Entry");
	    return;
	}
	cp = strchr (cp + 1, '/');
    }

    p = xmalloc (sizeof (struct an_entry));
    if (p == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    /* Leave space for serve_unchanged to write '=' if it wants.  */
    cp = xmalloc (strlen (arg) + 2);
    if (cp == NULL)
    {
	free (p);
	pending_error = ENOMEM;
	return;
    }
    strcpy (cp, arg);
    p->next = entries;
    p->entry = cp;
    entries = p;
}

static void serve_kopt PROTO ((char *));

static void
serve_kopt (arg)
     char *arg;
{
    if (error_pending ())
	return;

    if (kopt != NULL)
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text,
		     "E protocol error: duplicate Kopt request: %s", arg);
	return;
    }

    /* Do some sanity checks.  In particular, that it is not too long.
       This lets the rest of the code not worry so much about buffer
       overrun attacks.  Probably should call RCS_check_kflag here,
       but that would mean changing RCS_check_kflag to handle errors
       other than via exit(), fprintf(), and such.  */
    if (strlen (arg) > 10)
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text,
		     "E protocol error: invalid Kopt request: %s", arg);
	return;
    }

    kopt = xmalloc (strlen (arg) + 1);
    if (kopt == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    strcpy (kopt, arg);
}

static void serve_checkin_time PROTO ((char *));

static void
serve_checkin_time (arg)
     char *arg;
{
    if (error_pending ())
	return;

    if (checkin_time_valid)
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text,
		     "E protocol error: duplicate Checkin-time request: %s",
		     arg);
	return;
    }

    checkin_time = get_date (arg, NULL);
    if (checkin_time == (time_t)-1)
    {
	if (alloc_pending (80 + strlen (arg)))
	    sprintf (pending_error_text, "E cannot parse date %s", arg);
	return;
    }
    checkin_time_valid = 1;
}

static void
server_write_entries ()
{
    FILE *f;
    struct an_entry *p;
    struct an_entry *q;

    if (entries == NULL)
	return;

    f = NULL;
    /* Note that we free all the entries regardless of errors.  */
    if (!error_pending ())
    {
	/* We open in append mode because we don't want to clobber an
	   existing Entries file.  If we are checking out a module
	   which explicitly lists more than one file in a particular
	   directory, then we will wind up calling
	   server_write_entries for each such file.  */
	f = CVS_FOPEN (CVSADM_ENT, "a");
	if (f == NULL)
	{
	    int save_errno = errno;
	    if (alloc_pending (80 + strlen (CVSADM_ENT)))
		sprintf (pending_error_text, "E cannot open %s", CVSADM_ENT);
	    pending_error = save_errno;
	}
    }
    for (p = entries; p != NULL;)
    {
	if (!error_pending ())
	{
	    if (fprintf (f, "%s\n", p->entry) < 0)
	    {
		int save_errno = errno;
		if (alloc_pending (80 + strlen(CVSADM_ENT)))
		    sprintf (pending_error_text,
			     "E cannot write to %s", CVSADM_ENT);
		pending_error = save_errno;
	    }
	}
	free (p->entry);
	q = p->next;
	free (p);
	p = q;
    }
    entries = NULL;
    if (f != NULL && fclose (f) == EOF && !error_pending ())
    {
	int save_errno = errno;
	if (alloc_pending (80 + strlen (CVSADM_ENT)))
	    sprintf (pending_error_text, "E cannot close %s", CVSADM_ENT);
	pending_error = save_errno;
    }
}

struct notify_note {
    /* Directory in which this notification happens.  xmalloc'd*/
    char *dir;

    /* xmalloc'd.  */
    char *filename;

    /* The following three all in one xmalloc'd block, pointed to by TYPE.
       Each '\0' terminated.  */
    /* "E" or "U".  */
    char *type;
    /* time+host+dir */
    char *val;
    char *watches;

    struct notify_note *next;
};

static struct notify_note *notify_list;
/* Used while building list, to point to the last node that already exists.  */
static struct notify_note *last_node;

static void serve_notify PROTO ((char *));

static void
serve_notify (arg)
    char *arg;
{
    struct notify_note *new = NULL;
    char *data = NULL;
    int status;

    if (error_pending ()) return;

    if (outside_dir (arg))
	return;

    if (dir_name == NULL)
	goto error;

    new = (struct notify_note *) xmalloc (sizeof (struct notify_note));
    if (new == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    new->dir = xmalloc (strlen (dir_name) + 1);
    new->filename = xmalloc (strlen (arg) + 1);
    if (new->dir == NULL || new->filename == NULL)
    {
	pending_error = ENOMEM;
	if (new->dir != NULL)
	    free (new->dir);
	free (new);
	return;
    }
    strcpy (new->dir, dir_name);
    strcpy (new->filename, arg);

    status = buf_read_line (buf_from_net, &data, (int *) NULL);
    if (status != 0)
    {
	if (status == -2)
	    pending_error = ENOMEM;
	else
	{
	    pending_error_text = xmalloc (80 + strlen (arg));
	    if (pending_error_text == NULL)
		pending_error = ENOMEM;
	    else
	    {
		if (status == -1)
		    sprintf (pending_error_text,
			     "E end of file reading notification for %s", arg);
		else
		{
		    sprintf (pending_error_text,
			     "E error reading notification for %s", arg);
		    pending_error = status;
		}
	    }
	}
	free (new->filename);
	free (new->dir);
	free (new);
    }
    else
    {
	char *cp;

	if (!data[0])
	    goto error;

	if (strchr (data, '+'))
	    goto error;

	new->type = data;
	if (data[1] != '\t')
	    goto error;
	data[1] = '\0';
	cp = data + 2;
	new->val = cp;
	cp = strchr (cp, '\t');
	if (cp == NULL)
	    goto error;
	*cp++ = '+';
	cp = strchr (cp, '\t');
	if (cp == NULL)
	    goto error;
	*cp++ = '+';
	cp = strchr (cp, '\t');
	if (cp == NULL)
	    goto error;
	*cp++ = '\0';
	new->watches = cp;
	/* If there is another tab, ignore everything after it,
	   for future expansion.  */
	cp = strchr (cp, '\t');
	if (cp != NULL)
	{
	    *cp = '\0';
	}

	new->next = NULL;

	if (last_node == NULL)
	{
	    notify_list = new;
	}
	else
	    last_node->next = new;
	last_node = new;
    }
    return;
  error:
    pending_error = 0;
    if (alloc_pending (80))
	strcpy (pending_error_text,
		"E Protocol error; misformed Notify request");
    if (data != NULL)
	free (data);
    if (new != NULL)
    {
	free (new->filename);
	free (new->dir);
	free (new);
    }
    return;
}

/* Process all the Notify requests that we have stored up.  Returns 0
   if successful, if not prints error message (via error()) and
   returns negative value.  */
static int
server_notify ()
{
    struct notify_note *p;
    char *repos;

    while (notify_list != NULL)
    {
	if ( CVS_CHDIR (notify_list->dir) < 0)
	{
	    error (0, errno, "cannot change to %s", notify_list->dir);
	    return -1;
	}
	repos = Name_Repository (NULL, NULL);

	lock_dir_for_write (repos);

	fileattr_startdir (repos);

	notify_do (*notify_list->type, notify_list->filename, getcaller(),
		   notify_list->val, notify_list->watches, repos);

	buf_output0 (buf_to_net, "Notified ");
	{
	    char *dir = notify_list->dir + strlen (server_temp_dir) + 1;
	    if (dir[0] == '\0')
		buf_append_char (buf_to_net, '.');
	    else
		buf_output0 (buf_to_net, dir);
	    buf_append_char (buf_to_net, '/');
	    buf_append_char (buf_to_net, '\n');
	}
	buf_output0 (buf_to_net, repos);
	buf_append_char (buf_to_net, '/');
	buf_output0 (buf_to_net, notify_list->filename);
	buf_append_char (buf_to_net, '\n');
	free (repos);

	p = notify_list->next;
	free (notify_list->filename);
	free (notify_list->dir);
	free (notify_list->type);
	free (notify_list);
	notify_list = p;

	fileattr_write ();
	fileattr_free ();

	Lock_Cleanup ();
    }

    last_node = NULL;

    /* The code used to call fflush (stdout) here, but that is no
       longer necessary.  The data is now buffered in buf_to_net,
       which will be flushed by the caller, do_cvs_command.  */

    return 0;
}

static int argument_count;
static char **argument_vector;
static int argument_vector_size;

static void
serve_argument (arg)
     char *arg;
{
    char *p;

    if (error_pending()) return;
    
    if (argument_count >= 10000)
    {
	if (alloc_pending (80))
	    sprintf (pending_error_text, 
		     "E Protocol error: too many arguments");
	return;
    }

    if (argument_vector_size <= argument_count)
    {
	argument_vector_size *= 2;
	argument_vector =
	    (char **) xrealloc ((char *)argument_vector,
			       argument_vector_size * sizeof (char *));
	if (argument_vector == NULL)
	{
	    pending_error = ENOMEM;
	    return;
	}
    }
    p = xmalloc (strlen (arg) + 1);
    if (p == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    strcpy (p, arg);
    argument_vector[argument_count++] = p;
}

static void
serve_argumentx (arg)
     char *arg;
{
    char *p;

    if (error_pending()) return;
    
    if (argument_count <= 1) 
    {
	if (alloc_pending (80))
	    sprintf (pending_error_text,
		     "E Protocol error: called argumentx without prior call to argument");
	return;
    }

    p = argument_vector[argument_count - 1];
    p = xrealloc (p, strlen (p) + 1 + strlen (arg) + 1);
    if (p == NULL)
    {
	pending_error = ENOMEM;
	return;
    }
    strcat (p, "\n");
    strcat (p, arg);
    argument_vector[argument_count - 1] = p;
}

static void
serve_global_option (arg)
    char *arg;
{
    if (arg[0] != '-' || arg[1] == '\0' || arg[2] != '\0')
    {
    error_return:
	if (alloc_pending (strlen (arg) + 80))
	    sprintf (pending_error_text,
		     "E Protocol error: bad global option %s",
		     arg);
	return;
    }
    switch (arg[1])
    {
	case 'l':
	    error(0, 0, "WARNING: global `-l' option ignored.");
	    break;
	case 'n':
	    noexec = 1;
	    logoff = 1;
	    break;
	case 'q':
	    quiet = 1;
	    break;
	case 'r':
	    cvswrite = 0;
	    break;
	case 'Q':
	    really_quiet = 1;
	    break;
	case 't':
	    trace = 1;
	    break;
	default:
	    goto error_return;
    }
}

static void
serve_set (arg)
    char *arg;
{
    /* FIXME: This sends errors immediately (I think); they should be
       put into pending_error.  */
    variable_set (arg);
}

#ifdef ENCRYPTION

#ifdef HAVE_KERBEROS

static void
serve_kerberos_encrypt (arg)
     char *arg;
{
    /* All future communication with the client will be encrypted.  */

    buf_to_net = krb_encrypt_buffer_initialize (buf_to_net, 0, sched,
						kblock,
						buf_to_net->memory_error);
    buf_from_net = krb_encrypt_buffer_initialize (buf_from_net, 1, sched,
						  kblock,
						  buf_from_net->memory_error);
}

#endif /* HAVE_KERBEROS */

#ifdef HAVE_GSSAPI

static void
serve_gssapi_encrypt (arg)
     char *arg;
{
    if (cvs_gssapi_wrapping)
    {
	/* We're already using a gssapi_wrap buffer for stream
	   authentication.  Flush everything we've output so far, and
	   turn on encryption for future data.  On the input side, we
	   should only have unwrapped as far as the Gssapi-encrypt
	   command, so future unwrapping will become encrypted.  */
	buf_flush (buf_to_net, 1);
	cvs_gssapi_encrypt = 1;
	return;
    }

    /* All future communication with the client will be encrypted.  */

    cvs_gssapi_encrypt = 1;

    buf_to_net = cvs_gssapi_wrap_buffer_initialize (buf_to_net, 0,
						    gcontext,
						    buf_to_net->memory_error);
    buf_from_net = cvs_gssapi_wrap_buffer_initialize (buf_from_net, 1,
						      gcontext,
						      buf_from_net->memory_error);

    cvs_gssapi_wrapping = 1;
}

#endif /* HAVE_GSSAPI */

#endif /* ENCRYPTION */

#ifdef HAVE_GSSAPI

static void
serve_gssapi_authenticate (arg)
     char *arg;
{
    if (cvs_gssapi_wrapping)
    {
	/* We're already using a gssapi_wrap buffer for encryption.
	   That includes authentication, so we don't have to do
	   anything further.  */
	return;
    }

    buf_to_net = cvs_gssapi_wrap_buffer_initialize (buf_to_net, 0,
						    gcontext,
						    buf_to_net->memory_error);
    buf_from_net = cvs_gssapi_wrap_buffer_initialize (buf_from_net, 1,
						      gcontext,
						      buf_from_net->memory_error);

    cvs_gssapi_wrapping = 1;
}

#endif /* HAVE_GSSAPI */



#ifdef SERVER_FLOWCONTROL
/* The maximum we'll queue to the remote client before blocking.  */
# ifndef SERVER_HI_WATER
#  define SERVER_HI_WATER (2 * 1024 * 1024)
# endif /* SERVER_HI_WATER */
/* When the buffer drops to this, we restart the child */
# ifndef SERVER_LO_WATER
#  define SERVER_LO_WATER (1 * 1024 * 1024)
# endif /* SERVER_LO_WATER */
#endif /* SERVER_FLOWCONTROL */



static void serve_questionable PROTO((char *));

static void
serve_questionable (arg)
    char *arg;
{
    static int initted;

    if (!initted)
    {
	/* Pick up ignores from CVSROOTADM_IGNORE, $HOME/.cvsignore on server,
	   and CVSIGNORE on server.  */
	ign_setup ();
	initted = 1;
    }

    if (dir_name == NULL)
    {
	buf_output0 (buf_to_net, "E Protocol error: 'Directory' missing");
	return;
    }

    if (outside_dir (arg))
	return;

    if (!ign_name (arg))
    {
	char *update_dir;

	buf_output (buf_to_net, "M ? ", 4);
	update_dir = dir_name + strlen (server_temp_dir) + 1;
	if (!(update_dir[0] == '.' && update_dir[1] == '\0'))
	{
	    buf_output0 (buf_to_net, update_dir);
	    buf_output (buf_to_net, "/", 1);
	}
	buf_output0 (buf_to_net, arg);
	buf_output (buf_to_net, "\n", 1);
    }
}



static struct buffer *protocol;

/* This is the output which we are saving up to send to the server, in the
   child process.  We will push it through, via the `protocol' buffer, when
   we have a complete line.  */
static struct buffer *saved_output;
/* Likewise, but stuff which will go to stderr.  */
static struct buffer *saved_outerr;

static void
protocol_memory_error (buf)
    struct buffer *buf;
{
    error (1, ENOMEM, "Virtual memory exhausted");
}

/*
 * Process IDs of the subprocess, or negative if that subprocess
 * does not exist.
 */
static pid_t command_pid;

static void
outbuf_memory_error (buf)
    struct buffer *buf;
{
    static const char msg[] = "E Fatal server error\n\
error ENOMEM Virtual memory exhausted.\n";
    if (command_pid > 0)
	kill (command_pid, SIGTERM);

    /*
     * We have arranged things so that printing this now either will
     * be legal, or the "E fatal error" line will get glommed onto the
     * end of an existing "E" or "M" response.
     */

    /* If this gives an error, not much we could do.  syslog() it?  */
    write (STDOUT_FILENO, msg, sizeof (msg) - 1);
#ifdef HAVE_SYSLOG_H
    syslog (LOG_DAEMON | LOG_ERR, "virtual memory exhausted");
#endif
    error_exit ();
}

static void
input_memory_error (buf)
     struct buffer *buf;
{
    outbuf_memory_error (buf);
}



/* If command is legal, return 1.
 * Else if command is illegal and croak_on_illegal is set, then die.
 * Else just return 0 to indicate that command is illegal.
 */
static int
check_command_legal_p (cmd_name)
    char *cmd_name;
{
    /* Right now, only pserver notices illegal commands -- namely,
     * write attempts by a read-only user.  Therefore, if CVS_Username
     * is not set, this just returns 1, because CVS_Username unset
     * means pserver is not active.
     */
#ifdef AUTH_SERVER_SUPPORT
    if (CVS_Username == NULL)
	return 1;

    if (lookup_command_attribute (cmd_name) & CVS_CMD_MODIFIES_REPOSITORY)
    {
	/* This command has the potential to modify the repository, so
	 * we check if the user have permission to do that.
	 *
	 * (Only relevant for remote users -- local users can do
	 * whatever normal Unix file permissions allow them to do.)
	 *
	 * The decision method:
	 *
	 *    If $CVSROOT/CVSADMROOT_READERS exists and user is listed
	 *    in it, then read-only access for user.
	 *
	 *    Or if $CVSROOT/CVSADMROOT_WRITERS exists and user NOT
	 *    listed in it, then also read-only access for user.
	 *
	 *    Else read-write access for user.
	 */

	 char *linebuf = NULL;
	 int num_red = 0;
	 size_t linebuf_len = 0;
	 char *fname;
	 size_t flen;
	 FILE *fp;
	 int found_it = 0;

	 /* else */
	 flen = strlen (current_parsed_root->directory)
		+ strlen (CVSROOTADM)
		+ strlen (CVSROOTADM_READERS)
		+ 3;

	 fname = xmalloc (flen);
	 (void) sprintf (fname, "%s/%s/%s", current_parsed_root->directory,
			CVSROOTADM, CVSROOTADM_READERS);

	 fp = fopen (fname, "r");

	 if (fp == NULL)
	 {
	     if (!existence_error (errno))
	     {
		 /* Need to deny access, so that attackers can't fool
		    us with some sort of denial of service attack.  */
		 error (0, errno, "cannot open %s", fname);
		 free (fname);
		 return 0;
	     }
	 }
	 else  /* successfully opened readers file */
	 {
	     while ((num_red = getline (&linebuf, &linebuf_len, fp)) >= 0)
	     {
		 /* Hmmm, is it worth importing my own readline
		    library into CVS?  It takes care of chopping
		    leading and trailing whitespace, "#" comments, and
		    newlines automatically when so requested.  Would
		    save some code here...  -kff */

		 /* Chop newline by hand, for strcmp()'s sake. */
                 if (num_red > 0 && linebuf[num_red - 1] == '\n')
		     linebuf[num_red - 1] = '\0';

		 if (strcmp (linebuf, CVS_Username) == 0)
		     goto handle_illegal;
	     }
	     if (num_red < 0 && !feof (fp))
		 error (0, errno, "cannot read %s", fname);

	     /* If not listed specifically as a reader, then this user
		has write access by default unless writers are also
		specified in a file . */
	     if (fclose (fp) < 0)
		 error (0, errno, "cannot close %s", fname);
	 }
	 free (fname);

	 /* Now check the writers file.  */

	 flen = strlen (current_parsed_root->directory)
		+ strlen (CVSROOTADM)
		+ strlen (CVSROOTADM_WRITERS)
		+ 3;

	 fname = xmalloc (flen);
	 (void) sprintf (fname, "%s/%s/%s", current_parsed_root->directory,
			CVSROOTADM, CVSROOTADM_WRITERS);

	 fp = fopen (fname, "r");

	 if (fp == NULL)
	 {
	     if (linebuf)
		 free (linebuf);
	     if (existence_error (errno))
	     {
		 /* Writers file does not exist, so everyone is a writer,
		    by default.  */
		 free (fname);
		 return 1;
	     }
	     else
	     {
		 /* Need to deny access, so that attackers can't fool
		    us with some sort of denial of service attack.  */
		 error (0, errno, "cannot read %s", fname);
		 free (fname);
		 return 0;
	     }
	 }

	 found_it = 0;
	 while ((num_red = getline (&linebuf, &linebuf_len, fp)) >= 0)
	 {
	     /* Chop newline by hand, for strcmp()'s sake. */
	     if (num_red > 0 && linebuf[num_red - 1] == '\n')
		 linebuf[num_red - 1] = '\0';

	     if (strcmp (linebuf, CVS_Username) == 0)
	     {
		 found_it = 1;
		 break;
	     }
	 }
	 if (num_red < 0 && !feof (fp))
	     error (0, errno, "cannot read %s", fname);

	 if (found_it)
	 {
	     if (fclose (fp) < 0)
		 error (0, errno, "cannot close %s", fname);
	     if (linebuf)
		 free (linebuf);
	     free (fname);
	     return 1;
	 }
	 else   /* writers file exists, but this user not listed in it */
	 {
	 handle_illegal:
	     if (fclose (fp) < 0)
		 error (0, errno, "cannot close %s", fname);
	     if (linebuf)
		 free (linebuf);
	     free (fname);
	     return 0;
	 }
    }
#endif /* AUTH_SERVER_SUPPORT */

    /* If ever reach end of this function, command must be legal. */
    return 1;
}



/* Execute COMMAND in a subprocess with the approriate funky things done.  */

static struct fd_set_wrapper { fd_set fds; } command_fds_to_drain;
#ifdef SUNOS_KLUDGE
static int max_command_fd;
#endif

#ifdef SERVER_FLOWCONTROL
static int flowcontrol_pipe[2];
#endif /* SERVER_FLOWCONTROL */



/*
 * Set buffer FD to non-blocking I/O.  Returns 0 for success or errno
 * code.
 */
int
set_nonblock_fd (fd)
     int fd;
{
    int flags;

    flags = fcntl (fd, F_GETFL, 0);
    if (flags < 0)
	return errno;
    if (fcntl (fd, F_SETFL, flags | O_NONBLOCK) < 0)
	return errno;
    return 0;
}



/*
 * Set buffer FD to blocking I/O.  Returns 0 for success or errno code.
 */
int
set_block_fd (fd)
     int fd;
{
    int flags;

    flags = fcntl (fd, F_GETFL, 0);
    if (flags < 0)
	return errno;
    if (fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) < 0)
	return errno;
    return 0;
}



static void
do_cvs_command (cmd_name, command)
    char *cmd_name;
    int (*command) PROTO((int argc, char **argv));
{
    /*
     * The following file descriptors are set to -1 if that file is not
     * currently open.
     */

    /* Data on these pipes is a series of '\n'-terminated lines.  */
    int stdout_pipe[2];
    int stderr_pipe[2];

    /*
     * Data on this pipe is a series of counted (see buf_send_counted)
     * packets.  Each packet must be processed atomically (i.e. not
     * interleaved with data from stdout_pipe or stderr_pipe).
     */
    int protocol_pipe[2];

    int dev_null_fd = -1;

    int errs = 0;

    command_pid = -1;
    stdout_pipe[0] = -1;
    stdout_pipe[1] = -1;
    stderr_pipe[0] = -1;
    stderr_pipe[1] = -1;
    protocol_pipe[0] = -1;
    protocol_pipe[1] = -1;

    server_write_entries ();

    if (print_pending_error ())
	goto free_args_and_return;

    /* Global `cvs_cmd_name' is probably "server" right now -- only
       serve_export() sets it to anything else.  So we will use local
       parameter `cmd_name' to determine if this command is legal for
       this user.  */
    if (!check_command_legal_p (cmd_name))
    {
	buf_output0 (buf_to_net, "E ");
	buf_output0 (buf_to_net, program_name);
	buf_output0 (buf_to_net, " [server aborted]: \"");
	buf_output0 (buf_to_net, cmd_name);
	buf_output0 (buf_to_net, "\" requires write access to the repository\n\
error  \n");
	goto free_args_and_return;
    }
    cvs_cmd_name = cmd_name;

    (void) server_notify ();

    /*
     * We use a child process which actually does the operation.  This
     * is so we can intercept its standard output.  Even if all of CVS
     * were written to go to some special routine instead of writing
     * to stdout or stderr, we would still need to do the same thing
     * for the RCS commands.
     */

    if (pipe (stdout_pipe) < 0)
    {
	buf_output0 (buf_to_net, "E pipe failed\n");
	print_error (errno);
	goto error_exit;
    }
    if (pipe (stderr_pipe) < 0)
    {
	buf_output0 (buf_to_net, "E pipe failed\n");
	print_error (errno);
	goto error_exit;
    }
    if (pipe (protocol_pipe) < 0)
    {
	buf_output0 (buf_to_net, "E pipe failed\n");
	print_error (errno);
	goto error_exit;
    }
#ifdef SERVER_FLOWCONTROL
    if (pipe (flowcontrol_pipe) < 0)
    {
	buf_output0 (buf_to_net, "E pipe failed\n");
	print_error (errno);
	goto error_exit;
    }
    set_nonblock_fd (flowcontrol_pipe[0]);
    set_nonblock_fd (flowcontrol_pipe[1]);
#endif /* SERVER_FLOWCONTROL */

    dev_null_fd = CVS_OPEN (DEVNULL, O_RDONLY);
    if (dev_null_fd < 0)
    {
	buf_output0 (buf_to_net, "E open /dev/null failed\n");
	print_error (errno);
	goto error_exit;
    }

    /* We shouldn't have any partial lines from cvs_output and
       cvs_outerr, but we handle them here in case there is a bug.  */
    /* FIXME: appending a newline, rather than using "MT" as we
       do in the child process, is probably not really a very good
       way to "handle" them.  */
    if (! buf_empty_p (saved_output))
    {
	buf_append_char (saved_output, '\n');
	buf_copy_lines (buf_to_net, saved_output, 'M');
    }
    if (! buf_empty_p (saved_outerr))
    {
	buf_append_char (saved_outerr, '\n');
	buf_copy_lines (buf_to_net, saved_outerr, 'E');
    }

    /* Flush out any pending data.  */
    buf_flush (buf_to_net, 1);

    /* Don't use vfork; we're not going to exec().  */
    command_pid = fork ();
    if (command_pid < 0)
    {
	buf_output0 (buf_to_net, "E fork failed\n");
	print_error (errno);
	goto error_exit;
    }
    if (command_pid == 0)
    {
	int exitstatus;

	/* Since we're in the child, and the parent is going to take
	   care of packaging up our error messages, we can clear this
	   flag.  */
	error_use_protocol = 0;

	protocol = fd_buffer_initialize (protocol_pipe[1], 0,
					 protocol_memory_error);

	/* At this point we should no longer be using buf_to_net and
	   buf_from_net.  Instead, everything should go through
	   protocol.  */
	if (buf_to_net != NULL)
	{
	    buf_free (buf_to_net);
	    buf_to_net = NULL;
	}
	if (buf_from_net != NULL)
	{
	    buf_free (buf_from_net);
	    buf_from_net = NULL;
	}

	/* These were originally set up to use outbuf_memory_error.
	   Since we're now in the child, we should use the simpler
	   protocol_memory_error function.  */
	saved_output->memory_error = protocol_memory_error;
	saved_outerr->memory_error = protocol_memory_error;

	if (dup2 (dev_null_fd, STDIN_FILENO) < 0)
	    error (1, errno, "can't set up pipes");
	if (dup2 (stdout_pipe[1], STDOUT_FILENO) < 0)
	    error (1, errno, "can't set up pipes");
	if (dup2 (stderr_pipe[1], STDERR_FILENO) < 0)
	    error (1, errno, "can't set up pipes");
	close (dev_null_fd);
	close (stdout_pipe[0]);
	close (stdout_pipe[1]);
	close (stderr_pipe[0]);
	close (stderr_pipe[1]);
	close (protocol_pipe[0]);
	close_on_exec (protocol_pipe[1]);
#ifdef SERVER_FLOWCONTROL
	close_on_exec (flowcontrol_pipe[0]);
	close (flowcontrol_pipe[1]);
#endif /* SERVER_FLOWCONTROL */

	/*
	 * Set this in .bashrc if you want to give yourself time to attach
	 * to the subprocess with a debugger.
	 */
	if (getenv ("CVS_SERVER_SLEEP"))
	{
	    int secs = atoi (getenv ("CVS_SERVER_SLEEP"));
	    sleep (secs);
	}

	exitstatus = (*command) (argument_count, argument_vector);

	/* Output any partial lines.  If the client doesn't support
	   "MT", we go ahead and just tack on a newline since the
	   protocol doesn't support anything better.  */
	if (! buf_empty_p (saved_output))
	{
	    buf_output0 (protocol, supported_response ("MT") ? "MT text " : "M ");
	    buf_append_buffer (protocol, saved_output);
	    buf_output (protocol, "\n", 1);
	    buf_send_counted (protocol);
	}
	/* For now we just discard partial lines on stderr.  I suspect
	   that CVS can't write such lines unless there is a bug.  */

	buf_free (protocol);

	/* Close the pipes explicitly in order to send an EOF to the parent,
	 * then wait for the parent to close the flow control pipe.  This
	 * avoids a race condition where a child which dumped more than the
	 * high water mark into the pipes could complete its job and exit,
	 * leaving the parent process to attempt to write a stop byte to the
	 * closed flow control pipe, which earned the parent a SIGPIPE, which
	 * it normally only expects on the network pipe and that causes it to
	 * exit with an error message, rather than the SIGCHILD that it knows
	 * how to handle correctly.
	 */
	/* Let exit() close STDIN - it's from /dev/null anyhow.  */
	fclose (stderr);
	fclose (stdout);
	close (protocol_pipe[1]);
#ifdef SERVER_FLOWCONTROL
	{
	    char junk;
	    set_block_fd (flowcontrol_pipe[0]);
	    while (read (flowcontrol_pipe[0], &junk, 1) > 0);
	}
	/* FIXME: No point in printing an error message with error(),
	 * as STDERR is already closed, but perhaps this could be syslogged?
	 */
#endif

	rcs_cleanup ();
	Lock_Cleanup ();
	/* Don't call server_cleanup - the parent will handle that.  */
#ifdef SYSTEM_CLEANUP
	/* Hook for OS-specific behavior, for example socket subsystems on
	   NT and OS2 or dealing with windows and arguments on Mac.  */
	SYSTEM_CLEANUP ();
#endif
	exit (exitstatus);
    }

    /* OK, sit around getting all the input from the child.  */
    {
	struct buffer *stdoutbuf = NULL;
	struct buffer *stderrbuf = NULL;
	struct buffer *protocol_inbuf = NULL;
	int err_exit = 0;
	/* Number of file descriptors to check in select ().  */
	int num_to_check;
	int count_needed = 1;
#ifdef SERVER_FLOWCONTROL
	int have_flowcontrolled = 0;
#endif /* SERVER_FLOWCONTROL */

	FD_ZERO (&command_fds_to_drain.fds);
	num_to_check = stdout_pipe[0];
	FD_SET (stdout_pipe[0], &command_fds_to_drain.fds);
	if (stderr_pipe[0] > num_to_check)
	  num_to_check = stderr_pipe[0];
	FD_SET (stderr_pipe[0], &command_fds_to_drain.fds);
	if (protocol_pipe[0] > num_to_check)
	  num_to_check = protocol_pipe[0];
	FD_SET (protocol_pipe[0], &command_fds_to_drain.fds);
	if (STDOUT_FILENO > num_to_check)
	  num_to_check = STDOUT_FILENO;
#ifdef SUNOS_KLUDGE
	max_command_fd = num_to_check;
#endif
	/*
	 * File descriptors are numbered from 0, so num_to_check needs to
	 * be one larger than the largest descriptor.
	 */
	++num_to_check;
	if (num_to_check > FD_SETSIZE)
	{
	    buf_output0 (buf_to_net,
			 "E internal error: FD_SETSIZE not big enough.\n\
error  \n");
	    goto error_exit;
	}

	stdoutbuf = fd_buffer_initialize (stdout_pipe[0], 1,
					  input_memory_error);

	stderrbuf = fd_buffer_initialize (stderr_pipe[0], 1,
					  input_memory_error);

	protocol_inbuf = fd_buffer_initialize (protocol_pipe[0], 1,
					       input_memory_error);

	set_nonblock (buf_to_net);
	set_nonblock (stdoutbuf);
	set_nonblock (stderrbuf);
	set_nonblock (protocol_inbuf);

	if (close (stdout_pipe[1]) < 0)
	{
	    buf_output0 (buf_to_net, "E close failed\n");
	    print_error (errno);
	    err_exit = 1;
	    goto child_finish;
	}
	stdout_pipe[1] = -1;

	if (close (stderr_pipe[1]) < 0)
	{
	    buf_output0 (buf_to_net, "E close failed\n");
	    print_error (errno);
	    err_exit = 1;
	    goto child_finish;
	}
	stderr_pipe[1] = -1;

	if (close (protocol_pipe[1]) < 0)
	{
	    buf_output0 (buf_to_net, "E close failed\n");
	    print_error (errno);
	    err_exit = 1;
	    goto child_finish;
	}
	protocol_pipe[1] = -1;

#ifdef SERVER_FLOWCONTROL
	if (close (flowcontrol_pipe[0]) < 0)
	{
	    buf_output0 (buf_to_net, "E close failed\n");
	    print_error (errno);
	    err_exit = 1;
	    goto child_finish;
	}
	flowcontrol_pipe[0] = -1;
#endif /* SERVER_FLOWCONTROL */

	if (close (dev_null_fd) < 0)
	{
	    buf_output0 (buf_to_net, "E close failed\n");
	    print_error (errno);
	    dev_null_fd = -1;	/* Do not try to close it again. */
	    err_exit = 1;
	    goto child_finish;
	}
	dev_null_fd = -1;

	while (stdout_pipe[0] >= 0
	       || stderr_pipe[0] >= 0
	       || protocol_pipe[0] >= 0
	       || count_needed <= 0)
	{
	    fd_set readfds;
	    fd_set writefds;
	    int numfds;
	    struct timeval *timeout_ptr;
	    struct timeval timeout;
#ifdef SERVER_FLOWCONTROL
	    int bufmemsize;

	    /*
	     * See if we are swamping the remote client and filling our VM.
	     * Tell child to hold off if we do.
	     */
	    bufmemsize = buf_count_mem (buf_to_net);
	    if (!have_flowcontrolled && (bufmemsize > SERVER_HI_WATER))
	    {
		if (write(flowcontrol_pipe[1], "S", 1) == 1)
		    have_flowcontrolled = 1;
	    }
	    else if (have_flowcontrolled && (bufmemsize < SERVER_LO_WATER))
	    {
		if (write(flowcontrol_pipe[1], "G", 1) == 1)
		    have_flowcontrolled = 0;
	    }
#endif /* SERVER_FLOWCONTROL */

	    FD_ZERO (&readfds);
	    FD_ZERO (&writefds);

	    if (count_needed <= 0)
	    {
		/* there is data pending which was read from the protocol pipe
		 * so don't block if we don't find any data
		 */
		timeout.tv_sec = 0;
		timeout.tv_usec = 0;
		timeout_ptr = &timeout;
	    }
	    else
	    {
		/* block indefinately */
		timeout_ptr = NULL;
	    }

	    if (! buf_empty_p (buf_to_net))
		FD_SET (STDOUT_FILENO, &writefds);

	    if (stdout_pipe[0] >= 0)
	    {
		FD_SET (stdout_pipe[0], &readfds);
	    }
	    if (stderr_pipe[0] >= 0)
	    {
		FD_SET (stderr_pipe[0], &readfds);
	    }
	    if (protocol_pipe[0] >= 0)
	    {
		FD_SET (protocol_pipe[0], &readfds);
	    }

	    /* This process of selecting on the three pipes means that
	     we might not get output in the same order in which it
	     was written, thus producing the well-known
	     "out-of-order" bug.  If the child process uses
	     cvs_output and cvs_outerr, it will send everything on
	     the protocol_pipe and avoid this problem, so the
	     solution is to use cvs_output and cvs_outerr in the
	     child process.  */
	    do {
		/* This used to select on exceptions too, but as far
		   as I know there was never any reason to do that and
		   SCO doesn't let you select on exceptions on pipes.  */
		numfds = select (num_to_check, &readfds, &writefds,
				 (fd_set *)0, timeout_ptr);
		if (numfds < 0
			&& errno != EINTR)
		{
		    buf_output0 (buf_to_net, "E select failed\n");
		    print_error (errno);
		    err_exit = 1;
		    goto child_finish;
		}
	    } while (numfds < 0);

	    if (numfds == 0)
	    {
		FD_ZERO (&readfds);
		FD_ZERO (&writefds);
	    }

	    if (FD_ISSET (STDOUT_FILENO, &writefds))
	    {
		/* What should we do with errors?  syslog() them?  */
		buf_send_output (buf_to_net);
	    }

	    if (protocol_pipe[0] >= 0
		&& (FD_ISSET (protocol_pipe[0], &readfds)))
	    {
		int status;
		int count_read;

		status = buf_input_data (protocol_inbuf, &count_read);

		if (status == -1)
		{
		    close (protocol_pipe[0]);
		    protocol_pipe[0] = -1;
		}
		else if (status > 0)
		{
		    buf_output0 (buf_to_net, "E buf_input_data failed\n");
		    print_error (status);
		    err_exit = 1;
		    goto child_finish;
		}

		/*
		 * We only call buf_copy_counted if we have read
		 * enough bytes to make it worthwhile.  This saves us
		 * from continually recounting the amount of data we
		 * have.
		 */
		count_needed -= count_read;
	    }
	    /* this is still part of the protocol pipe procedure, but it is
	     * outside the above conditional so that unprocessed data can be
	     * left in the buffer and stderr/stdout can be read when a flush
	     * signal is received and control can return here without passing
	     * through the select code and maybe blocking
	     */
	    while (count_needed <= 0)
	    {
		int special = 0;

		count_needed = buf_copy_counted (buf_to_net,
						     protocol_inbuf,
						     &special);

		/* What should we do with errors?  syslog() them?  */
		buf_send_output (buf_to_net);

		/* If SPECIAL got set to <0, it means that the child
		 * wants us to flush the pipe & maybe stderr or stdout.
		 *
		 * After that we break to read stderr & stdout again before
		 * going back to the protocol pipe
		 *
		 * Upon breaking, count_needed = 0, so the next pass will only
		 * perform a non-blocking select before returning here to finish
		 * processing data we already read from the protocol buffer
		 */
		 if (special == -1)
		 {
		     cvs_flushout();
		     break;
		 }
		if (special == -2)
		{
		    /* If the client supports the 'F' command, we send it. */
		    if (supported_response ("F"))
		    {
			buf_append_char (buf_to_net, 'F');
			buf_append_char (buf_to_net, '\n');
		    }
		    cvs_flusherr ();
		    break;
		}
	    }

	    if (stdout_pipe[0] >= 0
		&& (FD_ISSET (stdout_pipe[0], &readfds)))
	    {
		int status;

		status = buf_input_data (stdoutbuf, (int *) NULL);

		buf_copy_lines (buf_to_net, stdoutbuf, 'M');

		if (status == -1)
		{
		    close (stdout_pipe[0]);
		    stdout_pipe[0] = -1;
		}
		else if (status > 0)
		{
		    buf_output0 (buf_to_net, "E buf_input_data failed\n");
		    print_error (status);
		    err_exit = 1;
		    goto child_finish;
		}

		/* What should we do with errors?  syslog() them?  */
		buf_send_output (buf_to_net);
	    }

	    if (stderr_pipe[0] >= 0
		&& (FD_ISSET (stderr_pipe[0], &readfds)))
	    {
		int status;

		status = buf_input_data (stderrbuf, (int *) NULL);

		buf_copy_lines (buf_to_net, stderrbuf, 'E');

		if (status == -1)
		{
		    close (stderr_pipe[0]);
		    stderr_pipe[0] = -1;
		}
		else if (status > 0)
		{
		    buf_output0 (buf_to_net, "E buf_input_data failed\n");
		    print_error (status);
		    err_exit = 1;
		    goto child_finish;
		}

		/* What should we do with errors?  syslog() them?  */
		buf_send_output (buf_to_net);
	    }
	}

	/*
	 * OK, we've gotten EOF on all the pipes.  If there is
	 * anything left on stdoutbuf or stderrbuf (this could only
	 * happen if there was no trailing newline), send it over.
	 */
	if (! buf_empty_p (stdoutbuf))
	{
	    buf_append_char (stdoutbuf, '\n');
	    buf_copy_lines (buf_to_net, stdoutbuf, 'M');
	}
	if (! buf_empty_p (stderrbuf))
	{
	    buf_append_char (stderrbuf, '\n');
	    buf_copy_lines (buf_to_net, stderrbuf, 'E');
	}
	if (! buf_empty_p (protocol_inbuf))
	    buf_output0 (buf_to_net,
			 "E Protocol error: uncounted data discarded\n");

#ifdef SERVER_FLOWCONTROL
	close (flowcontrol_pipe[1]);
	flowcontrol_pipe[1] = -1;
#endif /* SERVER_FLOWCONTROL */

	errs = 0;

	while (command_pid > 0)
	{
	    int status;
	    pid_t waited_pid;
	    waited_pid = waitpid (command_pid, &status, 0);
	    if (waited_pid < 0)
	    {
		/*
		 * Intentionally ignoring EINTR.  Other errors
		 * "can't happen".
		 */
		continue;
	    }

	    if (WIFEXITED (status))
		errs += WEXITSTATUS (status);
	    else
	    {
		int sig = WTERMSIG (status);
		char buf[50];
		/*
		 * This is really evil, because signals might be numbered
		 * differently on the two systems.  We should be using
		 * signal names (either of the "Terminated" or the "SIGTERM"
		 * variety).  But cvs doesn't currently use libiberty...we
		 * could roll our own....  FIXME.
		 */
		buf_output0 (buf_to_net, "E Terminated with fatal signal ");
		sprintf (buf, "%d\n", sig);
		buf_output0 (buf_to_net, buf);

		/* Test for a core dump.  */
		if (WCOREDUMP (status))
		{
		    buf_output0 (buf_to_net, "E Core dumped; preserving ");
		    buf_output0 (buf_to_net, orig_server_temp_dir);
		    buf_output0 (buf_to_net, " on server.\n\
E CVS locks may need cleaning up.\n");
		    dont_delete_temp = 1;
		}
		++errs;
	    }
	    if (waited_pid == command_pid)
		command_pid = -1;
	}

      child_finish:
	/*
	 * OK, we've waited for the child.  By now all CVS locks are free
	 * and it's OK to block on the network.
	 */
	set_block (buf_to_net);
	buf_flush (buf_to_net, 1);
	if (protocol_inbuf)
	{
	    buf_shutdown (protocol_inbuf);
	    buf_free (protocol_inbuf);
	    protocol_inbuf = NULL;
	}
	if (stderrbuf)
	{
	    buf_shutdown (stderrbuf);
	    buf_free (stderrbuf);
	    stderrbuf = NULL;
	}
	if (stdoutbuf)
	{
	    buf_shutdown (stdoutbuf);
	    buf_free (stdoutbuf);
	    stdoutbuf = NULL;
	}
	if (err_exit)
	    goto error_exit;
    }

    if (errs)
	/* We will have printed an error message already.  */
	buf_output0 (buf_to_net, "error  \n");
    else
	buf_output0 (buf_to_net, "ok\n");
    goto free_args_and_return;

 error_exit:
    if (command_pid > 0)
	kill (command_pid, SIGTERM);

    while (command_pid > 0)
    {
	pid_t waited_pid;
	waited_pid = waitpid (command_pid, (int *) 0, 0);
	if (waited_pid < 0 && errno == EINTR)
	    continue;
	if (waited_pid == command_pid)
	    command_pid = -1;
    }

    if (dev_null_fd >= 0)
	close (dev_null_fd);
    close (protocol_pipe[0]);
    close (protocol_pipe[1]);
    close (stderr_pipe[0]);
    close (stderr_pipe[1]);
    close (stdout_pipe[0]);
    close (stdout_pipe[1]);
#ifdef SERVER_FLOWCONTROL
    close (flowcontrol_pipe[0]);
    close (flowcontrol_pipe[1]);
#endif /* SERVER_FLOWCONTROL */

 free_args_and_return:
    /* Now free the arguments.  */
    {
	/* argument_vector[0] is a dummy argument, we don't mess with it.  */
	char **cp;
	for (cp = argument_vector + 1;
	     cp < argument_vector + argument_count;
	     ++cp)
	    free (*cp);

	argument_count = 1;
    }

    /* Flush out any data not yet sent.  */
    set_block (buf_to_net);
    buf_flush (buf_to_net, 1);

    return;
}

#ifdef SERVER_FLOWCONTROL
/*
 * Called by the child at convenient points in the server's execution for
 * the server child to block.. ie: when it has no locks active.
 */
void
server_pause_check()
{
    int paused = 0;
    char buf[1];

    while (read (flowcontrol_pipe[0], buf, 1) == 1)
    {
	if (*buf == 'S')	/* Stop */
	    paused = 1;
	else if (*buf == 'G')	/* Go */
	    paused = 0;
	else
	    return;		/* ??? */
    }
    while (paused) {
	int numfds, numtocheck;
	fd_set fds;

	FD_ZERO (&fds);
	FD_SET (flowcontrol_pipe[0], &fds);
	numtocheck = flowcontrol_pipe[0] + 1;

	do {
	    numfds = select (numtocheck, &fds, (fd_set *)0,
			     (fd_set *)0, (struct timeval *)NULL);
	    if (numfds < 0
		&& errno != EINTR)
	    {
		buf_output0 (buf_to_net, "E select failed\n");
		print_error (errno);
		return;
	    }
	} while (numfds < 0);

	if (FD_ISSET (flowcontrol_pipe[0], &fds))
	{
	    int got;

	    while ((got = read (flowcontrol_pipe[0], buf, 1)) == 1)
	    {
		if (*buf == 'S')	/* Stop */
		    paused = 1;
		else if (*buf == 'G')	/* Go */
		    paused = 0;
		else
		    return;		/* ??? */
	    }

	    /* This assumes that we are using BSD or POSIX nonblocking
	       I/O.  System V nonblocking I/O returns zero if there is
	       nothing to read.  */
	    if (got == 0)
		error (1, 0, "flow control EOF");
	    if (got < 0 && ! blocking_error (errno))
	    {
		error (1, errno, "flow control read failed");
	    }
	}
    }
}
#endif /* SERVER_FLOWCONTROL */

/* This variable commented in server.h.  */
char *server_dir = NULL;



static void output_dir PROTO((const char *, const char *));

static void
output_dir (update_dir, repository)
    const char *update_dir;
    const char *repository;
{
    if (server_dir != NULL)
    {
	buf_output0 (protocol, server_dir);
	buf_output0 (protocol, "/");
    }
    if (update_dir[0] == '\0')
	buf_output0 (protocol, ".");
    else
	buf_output0 (protocol, update_dir);
    buf_output0 (protocol, "/\n");
    buf_output0 (protocol, repository);
    buf_output0 (protocol, "/");
}



/*
 * Entries line that we are squirreling away to send to the client when
 * we are ready.
 */
static char *entries_line;

/*
 * File which has been Scratch_File'd, we are squirreling away that fact
 * to inform the client when we are ready.
 */
static char *scratched_file;

/*
 * The scratched_file will need to be removed as well as having its entry
 * removed.
 */
static int kill_scratched_file;



void
server_register (name, version, timestamp, options, tag, date, conflict)
    const char *name;
    const char *version;
    const char *timestamp;
    const char *options;
    const char *tag;
    const char *date;
    const char *conflict;
{
    int len;

    if (options == NULL)
	options = "";

    if (trace)
    {
	(void) fprintf (stderr,
			"%s-> server_register(%s, %s, %s, %s, %s, %s, %s)\n",
			CLIENT_SERVER_STR,
			name, version, timestamp ? timestamp : "", options,
			tag ? tag : "", date ? date : "",
			conflict ? conflict : "");
    }

    if (entries_line != NULL)
    {
	/*
	 * If CVS decides to Register it more than once (which happens
	 * on "cvs update foo/foo.c" where foo and foo.c are already
	 * checked out), use the last of the entries lines Register'd.
	 */
	free (entries_line);
    }

    /*
     * I have reports of Scratch_Entry and Register both happening, in
     * two different cases.  Using the last one which happens is almost
     * surely correct; I haven't tracked down why they both happen (or
     * even verified that they are for the same file).
     */
    if (scratched_file != NULL)
    {
	free (scratched_file);
	scratched_file = NULL;
    }

    len = (strlen (name) + strlen (version) + strlen (options) + 80);
    if (tag)
	len += strlen (tag);
    if (date)
	len += strlen (date);

    entries_line = xmalloc (len);
    sprintf (entries_line, "/%s/%s/", name, version);
    if (conflict != NULL)
    {
	strcat (entries_line, "+=");
    }
    strcat (entries_line, "/");
    strcat (entries_line, options);
    strcat (entries_line, "/");
    if (tag != NULL)
    {
	strcat (entries_line, "T");
	strcat (entries_line, tag);
    }
    else if (date != NULL)
    {
	strcat (entries_line, "D");
	strcat (entries_line, date);
    }
}



void
server_scratch (fname)
    const char *fname;
{
    /*
     * I have reports of Scratch_Entry and Register both happening, in
     * two different cases.  Using the last one which happens is almost
     * surely correct; I haven't tracked down why they both happen (or
     * even verified that they are for the same file).
     *
     * Don't know if this is what whoever wrote the above comment was
     * talking about, but this can happen in the case where a join
     * removes a file - the call to Register puts the '-vers' into the
     * Entries file after the file is removed
     */
    if (entries_line != NULL)
    {
	free (entries_line);
	entries_line = NULL;
    }

    if (scratched_file != NULL)
    {
	buf_output0 (protocol,
		     "E CVS server internal error: duplicate Scratch_Entry\n");
	buf_send_counted (protocol);
	return;
    }
    scratched_file = xstrdup (fname);
    kill_scratched_file = 1;
}

void
server_scratch_entry_only ()
{
    kill_scratched_file = 0;
}

/* Print a new entries line, from a previous server_register.  */
static void
new_entries_line ()
{
    if (entries_line)
    {
	buf_output0 (protocol, entries_line);
	buf_output (protocol, "\n", 1);
    }
    else
	/* Return the error message as the Entries line.  */
	buf_output0 (protocol,
		     "CVS server internal error: Register missing\n");
    free (entries_line);
    entries_line = NULL;
}


static void
serve_ci (arg)
    char *arg;
{
    do_cvs_command ("commit", commit);
}

static void
checked_in_response (file, update_dir, repository)
    char *file;
    char *update_dir;
    char *repository;
{
    if (supported_response ("Mode"))
    {
	struct stat sb;
	char *mode_string;

	if ( CVS_STAT (file, &sb) < 0)
	{
	    /* Not clear to me why the file would fail to exist, but it
	       was happening somewhere in the testsuite.  */
	    if (!existence_error (errno))
		error (0, errno, "cannot stat %s", file);
	}
	else
	{
	    buf_output0 (protocol, "Mode ");
	    mode_string = mode_to_string (sb.st_mode);
	    buf_output0 (protocol, mode_string);
	    buf_output0 (protocol, "\n");
	    free (mode_string);
	}
    }

    buf_output0 (protocol, "Checked-in ");
    output_dir (update_dir, repository);
    buf_output0 (protocol, file);
    buf_output (protocol, "\n", 1);
    new_entries_line ();
}

void
server_checked_in (file, update_dir, repository)
    const char *file;
    const char *update_dir;
    const char *repository;
{
    assert (file);
    assert (update_dir);
    assert (repository);

    if (noexec)
	return;
    if (scratched_file != NULL && entries_line == NULL)
    {
	/*
	 * This happens if we are now doing a "cvs remove" after a previous
	 * "cvs add" (without a "cvs ci" in between).
	 */
	buf_output0 (protocol, "Remove-entry ");
	output_dir (update_dir, repository);
	buf_output0 (protocol, file);
	buf_output (protocol, "\n", 1);
	free (scratched_file);
	scratched_file = NULL;
    }
    else
    {
	checked_in_response (file, update_dir, repository);
    }
    buf_send_counted (protocol);
}

void
server_update_entries (file, update_dir, repository, updated)
    const char *file;
    const char *update_dir;
    const char *repository;
    enum server_updated_arg4 updated;
{
    if (noexec)
	return;
    if (updated == SERVER_UPDATED)
	checked_in_response (file, update_dir, repository);
    else
    {
	if (!supported_response ("New-entry"))
	    return;
	buf_output0 (protocol, "New-entry ");
	output_dir (update_dir, repository);
	buf_output0 (protocol, file);
	buf_output (protocol, "\n", 1);
	new_entries_line ();
    }

    buf_send_counted (protocol);
}

static void
serve_update (arg)
    char *arg;
{
    do_cvs_command ("update", update);
}

static void
serve_diff (arg)
    char *arg;
{
    do_cvs_command ("diff", diff);
}

static void
serve_log (arg)
    char *arg;
{
    do_cvs_command ("log", cvslog);
}

static void
serve_rlog (arg)
    char *arg;
{
    do_cvs_command ("rlog", cvslog);
}

static void
serve_add (arg)
    char *arg;
{
    do_cvs_command ("add", add);
}

static void
serve_remove (arg)
    char *arg;
{
    do_cvs_command ("remove", cvsremove);
}

static void
serve_status (arg)
    char *arg;
{
    do_cvs_command ("status", cvsstatus);
}

static void
serve_rdiff (arg)
    char *arg;
{
    do_cvs_command ("rdiff", patch);
}

static void
serve_tag (arg)
    char *arg;
{
    do_cvs_command ("tag", cvstag);
}

static void
serve_rtag (arg)
    char *arg;
{
    do_cvs_command ("rtag", cvstag);
}

static void
serve_import (arg)
    char *arg;
{
    do_cvs_command ("import", import);
}

static void
serve_admin (arg)
    char *arg;
{
    do_cvs_command ("admin", admin);
}

static void
serve_history (arg)
    char *arg;
{
    do_cvs_command ("history", history);
}

static void
serve_release (arg)
    char *arg;
{
    do_cvs_command ("release", release);
}

static void serve_watch_on PROTO ((char *));

static void
serve_watch_on (arg)
    char *arg;
{
    do_cvs_command ("watch", watch_on);
}

static void serve_watch_off PROTO ((char *));

static void
serve_watch_off (arg)
    char *arg;
{
    do_cvs_command ("watch", watch_off);
}

static void serve_watch_add PROTO ((char *));

static void
serve_watch_add (arg)
    char *arg;
{
    do_cvs_command ("watch", watch_add);
}

static void serve_watch_remove PROTO ((char *));

static void
serve_watch_remove (arg)
    char *arg;
{
    do_cvs_command ("watch", watch_remove);
}

static void serve_watchers PROTO ((char *));

static void
serve_watchers (arg)
    char *arg;
{
    do_cvs_command ("watchers", watchers);
}

static void serve_editors PROTO ((char *));

static void
serve_editors (arg)
    char *arg;
{
    do_cvs_command ("editors", editors);
}

static void serve_noop PROTO ((char *));

static void
serve_noop (arg)
    char *arg;
{

    server_write_entries ();
    if (!print_pending_error ())
    {
	(void) server_notify ();
	buf_output0 (buf_to_net, "ok\n");
    }
    buf_flush (buf_to_net, 1);
}

static void serve_version PROTO ((char *));

static void
serve_version (arg)
    char *arg;
{
    do_cvs_command ("version", version);
}

static void serve_init PROTO ((char *));

static void
serve_init (arg)
    char *arg;
{
    if (alloc_pending (80 + strlen (arg)))
	sprintf (pending_error_text, "E init may not be run remotely");

    if (print_pending_error ())
	return;
}

static void serve_annotate PROTO ((char *));

static void
serve_annotate (arg)
    char *arg;
{
    do_cvs_command ("annotate", annotate);
}

static void serve_rannotate PROTO ((char *));

static void
serve_rannotate (arg)
    char *arg;
{
    do_cvs_command ("rannotate", annotate);
}

static void
serve_co (arg)
    char *arg;
{
    char *tempdir;
    int status;

    if (print_pending_error ())
	return;

    if (!isdir (CVSADM))
    {
	/*
	 * The client has not sent a "Repository" line.  Check out
	 * into a pristine directory.
	 */
	tempdir = xmalloc (strlen (server_temp_dir) + 80);
	if (tempdir == NULL)
	{
	    buf_output0 (buf_to_net, "E Out of memory\n");
	    return;
	}
	strcpy (tempdir, server_temp_dir);
	strcat (tempdir, "/checkout-dir");
	status = mkdir_p (tempdir);
	if (status != 0 && status != EEXIST)
	{
	    buf_output0 (buf_to_net, "E Cannot create ");
	    buf_output0 (buf_to_net, tempdir);
	    buf_append_char (buf_to_net, '\n');
	    print_error (errno);
	    free (tempdir);
	    return;
	}

	if ( CVS_CHDIR (tempdir) < 0)
	{
	    buf_output0 (buf_to_net, "E Cannot change to directory ");
	    buf_output0 (buf_to_net, tempdir);
	    buf_append_char (buf_to_net, '\n');
	    print_error (errno);
	    free (tempdir);
	    return;
	}
	free (tempdir);
    }

    /* Compensate for server_export()'s setting of cvs_cmd_name.
     *
     * [It probably doesn't matter if do_cvs_command() gets "export"
     *  or "checkout", but we ought to be accurate where possible.]
     */
    do_cvs_command ((strcmp (cvs_cmd_name, "export") == 0) ?
		    "export" : "checkout",
		    checkout);
}

static void
serve_export (arg)
    char *arg;
{
    /* Tell checkout() to behave like export not checkout.  */
    cvs_cmd_name = "export";
    serve_co (arg);
}



void
server_copy_file (file, update_dir, repository, newfile)
    const char *file;
    const char *update_dir;
    const char *repository;
    const char *newfile;
{
    /* At least for now, our practice is to have the server enforce
       noexec for the repository and the client enforce it for the
       working directory.  This might want more thought, and/or
       documentation in cvsclient.texi (other responses do it
       differently).  */

    if (!supported_response ("Copy-file"))
	return;
    buf_output0 (protocol, "Copy-file ");
    output_dir (update_dir, repository);
    buf_output0 (protocol, file);
    buf_output0 (protocol, "\n");
    buf_output0 (protocol, newfile);
    buf_output0 (protocol, "\n");
}

/* See server.h for description.  */

void
server_modtime (finfo, vers_ts)
    struct file_info *finfo;
    Vers_TS *vers_ts;
{
    char date[MAXDATELEN];
    char outdate[MAXDATELEN];

    assert (vers_ts->vn_rcs != NULL);

    if (!supported_response ("Mod-time"))
	return;

    if (RCS_getrevtime (finfo->rcs, vers_ts->vn_rcs, date, 0) == (time_t) -1)
	/* FIXME? should we be printing some kind of warning?  For one
	   thing I'm not 100% sure whether this happens in non-error
	   circumstances.  */
	return;
    date_to_internet (outdate, date);
    buf_output0 (protocol, "Mod-time ");
    buf_output0 (protocol, outdate);
    buf_output0 (protocol, "\n");
}

/* See server.h for description.  */

#if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__)
/* Need to prototype because mode_t might be smaller than int.  */
void
server_updated (
    struct file_info *finfo,
    Vers_TS *vers,
    enum server_updated_arg4 updated,
    mode_t mode,
    unsigned char *checksum,
    struct buffer *filebuf)
#else
void
server_updated (finfo, vers, updated, mode, checksum, filebuf)
    struct file_info *finfo;
    Vers_TS *vers;
    enum server_updated_arg4 updated;
    mode_t mode;
    unsigned char *checksum;
    struct buffer *filebuf;
#endif
{
    if (noexec)
    {
	/* Hmm, maybe if we did the same thing for entries_file, we
	   could get rid of the kludges in server_register and
	   server_scratch which refrain from warning if both
	   Scratch_Entry and Register get called.  Maybe.  */
	if (scratched_file)
	{
	    free (scratched_file);
	    scratched_file = NULL;
	}
	buf_send_counted (protocol);
	return;
    }

    if (entries_line != NULL && scratched_file == NULL)
    {
	FILE *f;
	struct buffer_data *list, *last;
	unsigned long size;
	char size_text[80];

	/* The contents of the file will be in one of filebuf,
	   list/last, or here.  */
	unsigned char *file;
	size_t file_allocated;
	size_t file_used;

	if (filebuf != NULL)
	{
	    size = buf_length (filebuf);
	    if (mode == (mode_t) -1)
		error (1, 0, "\
CVS server internal error: no mode in server_updated");
	}
	else
	{
	    struct stat sb;

	    if ( CVS_STAT (finfo->file, &sb) < 0)
	    {
		if (existence_error (errno))
		{
		    /* If we have a sticky tag for a branch on which
		       the file is dead, and cvs update the directory,
		       it gets a T_CHECKOUT but no file.  So in this
		       case just forget the whole thing.  */
		    free (entries_line);
		    entries_line = NULL;
		    goto done;
		}
		error (1, errno, "reading %s", finfo->fullname);
	    }
	    size = sb.st_size;
	    if (mode == (mode_t) -1)
	    {
		/* FIXME: When we check out files the umask of the
		   server (set in .bashrc if rsh is in use) affects
		   what mode we send, and it shouldn't.  */
		mode = sb.st_mode;
	    }
	}

	if (checksum != NULL)
	{
	    static int checksum_supported = -1;

	    if (checksum_supported == -1)
	    {
		checksum_supported = supported_response ("Checksum");
	    }

	    if (checksum_supported)
	    {
		int i;
		char buf[3];

		buf_output0 (protocol, "Checksum ");
		for (i = 0; i < 16; i++)
		{
		    sprintf (buf, "%02x", (unsigned int) checksum[i]);
		    buf_output0 (protocol, buf);
		}
		buf_append_char (protocol, '\n');
	    }
	}

	if (updated == SERVER_UPDATED)
	{
	    Node *node;

	    if (!(supported_response ("Created")
		  && supported_response ("Update-existing")))
		buf_output0 (protocol, "Updated ");
	    else
	    {
		assert (vers != NULL);
		if (vers->ts_user == NULL)
		    buf_output0 (protocol, "Created ");
		else
		    buf_output0 (protocol, "Update-existing ");
	    }

	    /* Now munge the entries to say that the file is unmodified,
	       in case we end up processing it again (e.g. modules3-6
	       in the testsuite).  */
	    node = findnode_fn (finfo->entries, finfo->file);
	    assert (node != NULL);
	    if (node != NULL)
	    {
		Entnode *entnode = node->data;
		free (entnode->timestamp);
		entnode->timestamp = xstrdup ("=");
	    }
	}
	else if (updated == SERVER_MERGED)
	    buf_output0 (protocol, "Merged ");
	else if (updated == SERVER_PATCHED)
	    buf_output0 (protocol, "Patched ");
	else if (updated == SERVER_RCS_DIFF)
	    buf_output0 (protocol, "Rcs-diff ");
	else
	    abort ();
	output_dir (finfo->update_dir, finfo->repository);
	buf_output0 (protocol, finfo->file);
	buf_output (protocol, "\n", 1);

	new_entries_line ();

	{
	    char *mode_string;

	    mode_string = mode_to_string (mode);
	    buf_output0 (protocol, mode_string);
	    buf_output0 (protocol, "\n");
	    free (mode_string);
	}

	list = last = NULL;

	file = NULL;
	file_allocated = 0;
	file_used = 0;

	if (size > 0)
	{
	    /* Throughout this section we use binary mode to read the
	       file we are sending.  The client handles any line ending
	       translation if necessary.  */

	    if (file_gzip_level
		/*
		 * For really tiny files, the gzip process startup
		 * time will outweigh the compression savings.  This
		 * might be computable somehow; using 100 here is just
		 * a first approximation.
		 */
		&& size > 100)
	    {
		/* Basing this routine on read_and_gzip is not a
		   high-performance approach.  But it seems easier
		   to code than the alternative (and less
		   vulnerable to subtle bugs).  Given that this feature
		   is mainly for compatibility, that is the better
		   tradeoff.  */

		int fd;

		/* Callers must avoid passing us a buffer if
		   file_gzip_level is set.  We could handle this case,
		   but it's not worth it since this case never arises
		   with a current client and server.  */
		if (filebuf != NULL)
		    error (1, 0, "\
CVS server internal error: unhandled case in server_updated");

		fd = CVS_OPEN (finfo->file, O_RDONLY | OPEN_BINARY, 0);
		if (fd < 0)
		    error (1, errno, "reading %s", finfo->fullname);
		if (read_and_gzip (fd, finfo->fullname, &file,
				   &file_allocated, &file_used,
				   file_gzip_level))
		    error (1, 0, "aborting due to compression error");
		size = file_used;
		if (close (fd) < 0)
		    error (1, errno, "reading %s", finfo->fullname);
		/* Prepending length with "z" is flag for using gzip here.  */
		buf_output0 (protocol, "z");
	    }
	    else if (filebuf == NULL)
	    {
		long status;

		f = CVS_FOPEN (finfo->file, "rb");
		if (f == NULL)
		    error (1, errno, "reading %s", finfo->fullname);
		status = buf_read_file (f, size, &list, &last);
		if (status == -2)
		    (*protocol->memory_error) (protocol);
		else if (status != 0)
		    error (1, ferror (f) ? errno : 0, "reading %s",
			   finfo->fullname);
		if (fclose (f) == EOF)
		    error (1, errno, "reading %s", finfo->fullname);
	    }
	}

	sprintf (size_text, "%lu\n", size);
	buf_output0 (protocol, size_text);

	if (file != NULL)
	{
	    buf_output (protocol, (char *) file, file_used);
	    free (file);
	    file = NULL;
	}
	else if (filebuf == NULL)
	    buf_append_data (protocol, list, last);
	else
	{
	    buf_append_buffer (protocol, filebuf);
	}
	/* Note we only send a newline here if the file ended with one.  */

	/*
	 * Avoid using up too much disk space for temporary files.
	 * A file which does not exist indicates that the file is up-to-date,
	 * which is now the case.  If this is SERVER_MERGED, the file is
	 * not up-to-date, and we indicate that by leaving the file there.
	 * I'm thinking of cases like "cvs update foo/foo.c foo".
	 */
	if ((updated == SERVER_UPDATED
	     || updated == SERVER_PATCHED
	     || updated == SERVER_RCS_DIFF)
	    && filebuf == NULL
	    /* But if we are joining, we'll need the file when we call
	       join_file.  */
	    && !joining ())
	{
	    if (CVS_UNLINK (finfo->file) < 0)
		error (0, errno, "cannot remove temp file for %s",
		       finfo->fullname);
	}
    }
    else if (scratched_file != NULL && entries_line == NULL)
    {
	if (strcmp (scratched_file, finfo->file) != 0)
	    error (1, 0,
		   "CVS server internal error: `%s' vs. `%s' scratched",
		   scratched_file,
		   finfo->file);
	free (scratched_file);
	scratched_file = NULL;

	if (kill_scratched_file)
	    buf_output0 (protocol, "Removed ");
	else
	    buf_output0 (protocol, "Remove-entry ");
	output_dir (finfo->update_dir, finfo->repository);
	buf_output0 (protocol, finfo->file);
	buf_output (protocol, "\n", 1);
	/* keep the vers structure up to date in case we do a join
	 * - if there isn't a file, it can't very well have a version number, can it?
	 *
	 * we do it here on the assumption that since we just told the client
	 * to remove the file/entry, it will, and we want to remember that.
	 * If it fails, that's the client's problem, not ours
	 */
	if (vers && vers->vn_user != NULL)
	{
	    free (vers->vn_user);
	    vers->vn_user = NULL;
	}
	if (vers && vers->ts_user != NULL)
	{
	    free (vers->ts_user);
	    vers->ts_user = NULL;
	}
    }
    else if (scratched_file == NULL && entries_line == NULL)
    {
	/*
	 * This can happen with death support if we were processing
	 * a dead file in a checkout.
	 */
    }
    else
	error (1, 0,
	       "CVS server internal error: Register *and* Scratch_Entry.\n");
    buf_send_counted (protocol);
  done:;
}

/* Return whether we should send patches in RCS format.  */

int
server_use_rcs_diff ()
{
    return supported_response ("Rcs-diff");
}



void
server_set_entstat (update_dir, repository)
    const char *update_dir;
    const char *repository;
{
    static int set_static_supported = -1;
    if (set_static_supported == -1)
	set_static_supported = supported_response ("Set-static-directory");
    if (!set_static_supported) return;

    buf_output0 (protocol, "Set-static-directory ");
    output_dir (update_dir, repository);
    buf_output0 (protocol, "\n");
    buf_send_counted (protocol);
}



void
server_clear_entstat (update_dir, repository)
     const char *update_dir;
     const char *repository;
{
    static int clear_static_supported = -1;
    if (clear_static_supported == -1)
	clear_static_supported = supported_response ("Clear-static-directory");
    if (!clear_static_supported) return;

    if (noexec)
	return;

    buf_output0 (protocol, "Clear-static-directory ");
    output_dir (update_dir, repository);
    buf_output0 (protocol, "\n");
    buf_send_counted (protocol);
}



void
server_set_sticky (update_dir, repository, tag, date, nonbranch)
    const char *update_dir;
    const char *repository;
    const char *tag;
    const char *date;
    int nonbranch;
{
    static int set_sticky_supported = -1;

    assert (update_dir != NULL);

    if (set_sticky_supported == -1)
	set_sticky_supported = supported_response ("Set-sticky");
    if (!set_sticky_supported) return;

    if (noexec)
	return;

    if (tag == NULL && date == NULL)
    {
	buf_output0 (protocol, "Clear-sticky ");
	output_dir (update_dir, repository);
	buf_output0 (protocol, "\n");
    }
    else
    {
	buf_output0 (protocol, "Set-sticky ");
	output_dir (update_dir, repository);
	buf_output0 (protocol, "\n");
	if (tag != NULL)
	{
	    if (nonbranch)
		buf_output0 (protocol, "N");
	    else
		buf_output0 (protocol, "T");
	    buf_output0 (protocol, tag);
	}
	else
	{
	    buf_output0 (protocol, "D");
	    buf_output0 (protocol, date);
	}
	buf_output0 (protocol, "\n");
    }
    buf_send_counted (protocol);
}

struct template_proc_data
{
    const char *update_dir;
    const char *repository;
};

/* Here as a static until we get around to fixing Parse_Info to pass along
   a void * for it.  */
static struct template_proc_data *tpd;

static int
template_proc PROTO((const char *repository, const char *template));

static int
template_proc (repository, template)
    const char *repository;
    const char *template;
{
    FILE *fp;
    char buf[1024];
    size_t n;
    struct stat sb;
    struct template_proc_data *data = tpd;

    if (!supported_response ("Template"))
	/* Might want to warn the user that the rcsinfo feature won't work.  */
	return 0;
    buf_output0 (protocol, "Template ");
    output_dir (data->update_dir, data->repository);
    buf_output0 (protocol, "\n");

    fp = CVS_FOPEN (template, "rb");
    if (fp == NULL)
    {
	error (0, errno, "Couldn't open rcsinfo template file %s", template);
	return 1;
    }
    if (fstat (fileno (fp), &sb) < 0)
    {
	error (0, errno, "cannot stat rcsinfo template file %s", template);
	return 1;
    }
    sprintf (buf, "%ld\n", (long) sb.st_size);
    buf_output0 (protocol, buf);
    while (!feof (fp))
    {
	n = fread (buf, 1, sizeof buf, fp);
	buf_output (protocol, buf, n);
	if (ferror (fp))
	{
	    error (0, errno, "cannot read rcsinfo template file %s", template);
	    (void) fclose (fp);
	    return 1;
	}
    }
    buf_send_counted (protocol);
    if (fclose (fp) < 0)
	error (0, errno, "cannot close rcsinfo template file %s", template);
    return 0;
}



void
server_template (update_dir, repository)
    const char *update_dir;
    const char *repository;
{
    struct template_proc_data data;
    data.update_dir = update_dir;
    data.repository = repository;
    tpd = &data;
    (void) Parse_Info (CVSROOTADM_RCSINFO, repository, template_proc, 1);
}



static void
serve_gzip_contents (arg)
     char *arg;
{
    int level;
    level = atoi (arg);
    if (level == 0)
	level = 6;
    file_gzip_level = level;
}

static void
serve_gzip_stream (arg)
     char *arg;
{
    int level;
    level = atoi (arg);
    if (level == 0)
	level = 6;

    /* All further communication with the client will be compressed.  */

    buf_to_net = compress_buffer_initialize (buf_to_net, 0, level,
					     buf_to_net->memory_error);
    buf_from_net = compress_buffer_initialize (buf_from_net, 1, level,
					       buf_from_net->memory_error);
}

/* Tell the client about RCS options set in CVSROOT/cvswrappers. */
static void
serve_wrapper_sendme_rcs_options (arg)
     char *arg;
{
    /* Actually, this is kind of sdrawkcab-ssa: the client wants
     * verbatim lines from a cvswrappers file, but the server has
     * already parsed the cvswrappers file into the wrap_list struct.
     * Therefore, the server loops over wrap_list, unparsing each
     * entry before sending it.
     */
    char *wrapper_line = NULL;

    wrap_setup ();

    for (wrap_unparse_rcs_options (&wrapper_line, 1);
	 wrapper_line;
	 wrap_unparse_rcs_options (&wrapper_line, 0))
    {
	buf_output0 (buf_to_net, "Wrapper-rcsOption ");
	buf_output0 (buf_to_net, wrapper_line);
	buf_output0 (buf_to_net, "\012");;
	free (wrapper_line);
    }

    buf_output0 (buf_to_net, "ok\012");

    /* The client is waiting for us, so we better send the data now.  */
    buf_flush (buf_to_net, 1);
}


static void
serve_ignore (arg)
    char *arg;
{
    /*
     * Just ignore this command.  This is used to support the
     * update-patches command, which is not a real command, but a signal
     * to the client that update will accept the -u argument.
     */
}

static int
expand_proc (argc, argv, where, mwhere, mfile, shorten,
	     local_specified, omodule, msg)
    int argc;
    char **argv;
    char *where;
    char *mwhere;
    char *mfile;
    int shorten;
    int local_specified;
    char *omodule;
    char *msg;
{
    int i;
    char *dir = argv[0];

    /* If mwhere has been specified, the thing we're expanding is a
       module -- just return its name so the client will ask for the
       right thing later.  If it is an alias or a real directory,
       mwhere will not be set, so send out the appropriate
       expansion. */

    if (mwhere != NULL)
    {
	buf_output0 (buf_to_net, "Module-expansion ");
	if (server_dir != NULL)
	{
	    buf_output0 (buf_to_net, server_dir);
	    buf_output0 (buf_to_net, "/");
	}
	buf_output0 (buf_to_net, mwhere);
	if (mfile != NULL)
	{
	    buf_append_char (buf_to_net, '/');
	    buf_output0 (buf_to_net, mfile);
	}
	buf_append_char (buf_to_net, '\n');
    }
    else
    {
	/* We may not need to do this anymore -- check the definition
	   of aliases before removing */
	if (argc == 1)
	{
	    buf_output0 (buf_to_net, "Module-expansion ");
	    if (server_dir != NULL)
	    {
		buf_output0 (buf_to_net, server_dir);
		buf_output0 (buf_to_net, "/");
	    }
	    buf_output0 (buf_to_net, dir);
	    buf_append_char (buf_to_net, '\n');
	}
	else
	{
	    for (i = 1; i < argc; ++i)
	    {
		buf_output0 (buf_to_net, "Module-expansion ");
		if (server_dir != NULL)
		{
		    buf_output0 (buf_to_net, server_dir);
		    buf_output0 (buf_to_net, "/");
		}
		buf_output0 (buf_to_net, dir);
		buf_append_char (buf_to_net, '/');
		buf_output0 (buf_to_net, argv[i]);
		buf_append_char (buf_to_net, '\n');
	    }
	}
    }
    return 0;
}

static void
serve_expand_modules (arg)
    char *arg;
{
    int i;
    int err;
    DBM *db;
    err = 0;

    db = open_module ();
    for (i = 1; i < argument_count; i++)
	err += do_module (db, argument_vector[i],
			  CHECKOUT, "Updating", expand_proc,
			  NULL, 0, 0, 0, 0,
			  (char *) NULL);
    close_module (db);
    {
	/* argument_vector[0] is a dummy argument, we don't mess with it.  */
	char **cp;
	for (cp = argument_vector + 1;
	     cp < argument_vector + argument_count;
	     ++cp)
	    free (*cp);

	argument_count = 1;
    }
    if (err)
	/* We will have printed an error message already.  */
	buf_output0 (buf_to_net, "error  \n");
    else
	buf_output0 (buf_to_net, "ok\n");

    /* The client is waiting for the module expansions, so we must
       send the output now.  */
    buf_flush (buf_to_net, 1);
}



static void serve_valid_requests PROTO((char *arg));

#endif /* SERVER_SUPPORT */
#if defined(SERVER_SUPPORT) || defined(CLIENT_SUPPORT)

/*
 * Parts of this table are shared with the client code,
 * but the client doesn't need to know about the handler
 * functions.
 */

struct request requests[] =
{
#ifdef SERVER_SUPPORT
#define REQ_LINE(n, f, s) {n, f, s}
#else
#define REQ_LINE(n, f, s) {n, s}
#endif

  REQ_LINE("Root", serve_root, RQ_ESSENTIAL | RQ_ROOTLESS),
  REQ_LINE("Valid-responses", serve_valid_responses,
	   RQ_ESSENTIAL | RQ_ROOTLESS),
  REQ_LINE("valid-requests", serve_valid_requests,
	   RQ_ESSENTIAL | RQ_ROOTLESS),
  REQ_LINE("Repository", serve_repository, 0),
  REQ_LINE("Directory", serve_directory, RQ_ESSENTIAL),
  REQ_LINE("Max-dotdot", serve_max_dotdot, 0),
  REQ_LINE("Static-directory", serve_static_directory, 0),
  REQ_LINE("Sticky", serve_sticky, 0),
  REQ_LINE("Entry", serve_entry, RQ_ESSENTIAL),
  REQ_LINE("Kopt", serve_kopt, 0),
  REQ_LINE("Checkin-time", serve_checkin_time, 0),
  REQ_LINE("Modified", serve_modified, RQ_ESSENTIAL),
  REQ_LINE("Is-modified", serve_is_modified, 0),
  REQ_LINE("Empty-conflicts", serve_noop, 0),

  /* The client must send this request to interoperate with CVS 1.5
     through 1.9 servers.  The server must support it (although it can
     be and is a noop) to interoperate with CVS 1.5 to 1.9 clients.  */
  REQ_LINE("UseUnchanged", serve_enable_unchanged, RQ_ENABLEME | RQ_ROOTLESS),

  REQ_LINE("Unchanged", serve_unchanged, RQ_ESSENTIAL),
  REQ_LINE("Notify", serve_notify, 0),
  REQ_LINE("Questionable", serve_questionable, 0),
  REQ_LINE("Argument", serve_argument, RQ_ESSENTIAL),
  REQ_LINE("Argumentx", serve_argumentx, RQ_ESSENTIAL),
  REQ_LINE("Global_option", serve_global_option, RQ_ROOTLESS),
  REQ_LINE("Gzip-stream", serve_gzip_stream, 0),
  REQ_LINE("wrapper-sendme-rcsOptions",
	   serve_wrapper_sendme_rcs_options,
	   0),
  REQ_LINE("Set", serve_set, RQ_ROOTLESS),
#ifdef ENCRYPTION
#  ifdef HAVE_KERBEROS
  REQ_LINE("Kerberos-encrypt", serve_kerberos_encrypt, 0),
#  endif
#  ifdef HAVE_GSSAPI
  REQ_LINE("Gssapi-encrypt", serve_gssapi_encrypt, 0),
#  endif
#endif
#ifdef HAVE_GSSAPI
  REQ_LINE("Gssapi-authenticate", serve_gssapi_authenticate, 0),
#endif
  REQ_LINE("expand-modules", serve_expand_modules, 0),
  REQ_LINE("ci", serve_ci, RQ_ESSENTIAL),
  REQ_LINE("co", serve_co, RQ_ESSENTIAL),
  REQ_LINE("update", serve_update, RQ_ESSENTIAL),
  REQ_LINE("diff", serve_diff, 0),
  REQ_LINE("log", serve_log, 0),
  REQ_LINE("rlog", serve_rlog, 0),
  REQ_LINE("add", serve_add, 0),
  REQ_LINE("remove", serve_remove, 0),
  REQ_LINE("update-patches", serve_ignore, 0),
  REQ_LINE("gzip-file-contents", serve_gzip_contents, 0),
  REQ_LINE("status", serve_status, 0),
  REQ_LINE("rdiff", serve_rdiff, 0),
  REQ_LINE("tag", serve_tag, 0),
  REQ_LINE("rtag", serve_rtag, 0),
  REQ_LINE("import", serve_import, 0),
  REQ_LINE("admin", serve_admin, 0),
  REQ_LINE("export", serve_export, 0),
  REQ_LINE("history", serve_history, 0),
  REQ_LINE("release", serve_release, 0),
  REQ_LINE("watch-on", serve_watch_on, 0),
  REQ_LINE("watch-off", serve_watch_off, 0),
  REQ_LINE("watch-add", serve_watch_add, 0),
  REQ_LINE("watch-remove", serve_watch_remove, 0),
  REQ_LINE("watchers", serve_watchers, 0),
  REQ_LINE("editors", serve_editors, 0),
  REQ_LINE("init", serve_init, RQ_ROOTLESS),
  REQ_LINE("annotate", serve_annotate, 0),
  REQ_LINE("rannotate", serve_rannotate, 0),
  REQ_LINE("noop", serve_noop, RQ_ROOTLESS),
  REQ_LINE("version", serve_version, RQ_ROOTLESS),
  REQ_LINE(NULL, NULL, 0)

#undef REQ_LINE
};

#endif /* SERVER_SUPPORT or CLIENT_SUPPORT */
#ifdef SERVER_SUPPORT

static void
serve_valid_requests (arg)
     char *arg;
{
    struct request *rq;
    if (print_pending_error ())
	return;
    buf_output0 (buf_to_net, "Valid-requests");
    for (rq = requests; rq->name != NULL; rq++)
    {
	if (rq->func != NULL)
	{
	    buf_append_char (buf_to_net, ' ');
	    buf_output0 (buf_to_net, rq->name);
	}
    }
    buf_output0 (buf_to_net, "\nok\n");

    /* The client is waiting for the list of valid requests, so we
       must send the output now.  */
    buf_flush (buf_to_net, 1);
}

#ifdef SUNOS_KLUDGE
/*
 * Delete temporary files.  SIG is the signal making this happen, or
 * 0 if not called as a result of a signal.
 */
static int command_pid_is_dead;
static void wait_sig (sig)
     int sig;
{
    int status;
    pid_t r = wait (&status);
    if (r == command_pid)
	command_pid_is_dead++;
}
#endif /* SUNOS_KLUDGE */

void
server_cleanup (sig)
    int sig;
{
    /* Do "rm -rf" on the temp directory.  */
    int status;
    int save_noexec;

    if (buf_to_net != NULL)
    {
	/* Since we're done, go ahead and put BUF_TO_NET back into blocking
	 * mode and send any pending output.  In the usual case there won't
	 * won't be any, but there might be if an error occured.
	 */

	set_block (buf_to_net);
	buf_flush (buf_to_net, 1);

	/* Next we shut down BUF_FROM_NET.  That will pick up the checksum
	 * generated when the client shuts down its buffer.  Then, after we
	 * have generated any final output, we shut down BUF_TO_NET.
	 */

	if (buf_from_net != NULL)
	{
	    status = buf_shutdown (buf_from_net);
	    if (status != 0)
		error (0, status, "shutting down buffer from client");
	    buf_free (buf_from_net);
	    buf_from_net = NULL;
	}

	if (dont_delete_temp)
	{
	    (void) buf_flush (buf_to_net, 1);
	    (void) buf_shutdown (buf_to_net);
	    buf_free (buf_to_net);
	    buf_to_net = NULL;
	    error_use_protocol = 0;
	    return;
	}
    }
    else if (dont_delete_temp)
	return;

    /* What a bogus kludge.  This disgusting code makes all kinds of
       assumptions about SunOS, and is only for a bug in that system.
       So only enable it on Suns.  */
#ifdef SUNOS_KLUDGE
    if (command_pid > 0)
    {
	/* To avoid crashes on SunOS due to bugs in SunOS tmpfs
	   triggered by the use of rename() in RCS, wait for the
	   subprocess to die.  Unfortunately, this means draining output
	   while waiting for it to unblock the signal we sent it.  Yuck!  */
	int status;
	pid_t r;

	signal (SIGCHLD, wait_sig);
	if (sig)
	    /* Perhaps SIGTERM would be more correct.  But the child
	       process will delay the SIGINT delivery until its own
	       children have exited.  */
	    kill (command_pid, SIGINT);
	/* The caller may also have sent a signal to command_pid, so
	   always try waiting.  First, though, check and see if it's still
	   there....  */
    do_waitpid:
	r = waitpid (command_pid, &status, WNOHANG);
	if (r == 0)
	    ;
	else if (r == command_pid)
	    command_pid_is_dead++;
	else if (r == -1)
	    switch (errno)
	    {
		case ECHILD:
		    command_pid_is_dead++;
		    break;
		case EINTR:
		    goto do_waitpid;
	    }
	else
	    /* waitpid should always return one of the above values */
	    abort ();
	while (!command_pid_is_dead)
	{
	    struct timeval timeout;
	    struct fd_set_wrapper readfds;
	    char buf[100];
	    int i;

	    /* Use a non-zero timeout to avoid eating up CPU cycles.  */
	    timeout.tv_sec = 2;
	    timeout.tv_usec = 0;
	    readfds = command_fds_to_drain;
	    switch (select (max_command_fd + 1, &readfds.fds,
			    (fd_set *)0, (fd_set *)0,
			    &timeout))
	    {
		case -1:
		    if (errno != EINTR)
			abort ();
		case 0:
		    /* timeout */
		    break;
		case 1:
		    for (i = 0; i <= max_command_fd; i++)
		    {
			if (!FD_ISSET (i, &readfds.fds))
			    continue;
			/* this fd is non-blocking */
			while (read (i, buf, sizeof (buf)) >= 1)
			    ;
		    }
		    break;
		default:
		    abort ();
	    }
	}
    }
#endif /* SUNOS_KLUDGE */

    CVS_CHDIR (Tmpdir);
    /* Temporarily clear noexec, so that we clean up our temp directory
       regardless of it (this could more cleanly be handled by moving
       the noexec check to all the unlink_file_dir callers from
       unlink_file_dir itself).  */
    save_noexec = noexec;
    noexec = 0;
    /* FIXME?  Would be nice to not ignore errors.  But what should we do?
       We could try to do this before we shut down the network connection,
       and try to notify the client (but the client might not be waiting
       for responses).  We could try something like syslog() or our own
       log file.  */
    unlink_file_dir (orig_server_temp_dir);
    noexec = save_noexec;

    if (buf_to_net != NULL)
    {
	(void) buf_flush (buf_to_net, 1);
	(void) buf_shutdown (buf_to_net);
	buf_free (buf_to_net);
	buf_to_net = NULL;
	error_use_protocol = 0;
    }
}

int
server (argc, argv)
     int argc;
     char **argv;
{
    char *error_prog_name;		/* Used in error messages */

    if (argc == -1)
    {
	static const char *const msg[] =
	{
	    "Usage: %s %s\n",
	    "  Normally invoked by a cvs client on a remote machine.\n",
	    NULL
	};
	usage (msg);
    }
    /* Ignore argc and argv.  They might be from .cvsrc.  */

    buf_to_net = fd_buffer_initialize (STDOUT_FILENO, 0,
				       outbuf_memory_error);
    buf_from_net = stdio_buffer_initialize (stdin, 0, 1, outbuf_memory_error);

    saved_output = buf_nonio_initialize (outbuf_memory_error);
    saved_outerr = buf_nonio_initialize (outbuf_memory_error);

    /* Since we're in the server parent process, error should use the
       protocol to report error messages.  */
    error_use_protocol = 1;

    /* OK, now figure out where we stash our temporary files.  */
    {
	char *p;

	/* The code which wants to chdir into server_temp_dir is not set
	   up to deal with it being a relative path.  So give an error
	   for that case.  */
	if (!isabsolute (Tmpdir))
	{
	    if (alloc_pending (80 + strlen (Tmpdir)))
		sprintf (pending_error_text,
			 "E Value of %s for TMPDIR is not absolute", Tmpdir);

	    /* FIXME: we would like this error to be persistent, that
	       is, not cleared by print_pending_error.  The current client
	       will exit as soon as it gets an error, but the protocol spec
	       does not require a client to do so.  */
	}
	else
	{
	    int status;
	    int i = 0;

	    server_temp_dir = xmalloc (strlen (Tmpdir) + 80);
	    if (server_temp_dir == NULL)
	    {
		/*
		 * Strictly speaking, we're not supposed to output anything
		 * now.  But we're about to exit(), give it a try.
		 */
		printf ("E Fatal server error, aborting.\n\
error ENOMEM Virtual memory exhausted.\n");

		error_exit ();
	    }
	    strcpy (server_temp_dir, Tmpdir);

	    /* Remove a trailing slash from TMPDIR if present.  */
	    p = server_temp_dir + strlen (server_temp_dir) - 1;
	    if (*p == '/')
		*p = '\0';

	    /*
	     * I wanted to use cvs-serv/PID, but then you have to worry about
	     * the permissions on the cvs-serv directory being right.  So
	     * use cvs-servPID.
	     */
	    strcat (server_temp_dir, "/cvs-serv");

	    p = server_temp_dir + strlen (server_temp_dir);
	    sprintf (p, "%ld", (long) getpid ());

	    orig_server_temp_dir = server_temp_dir;

	    /* Create the temporary directory, and set the mode to
	       700, to discourage random people from tampering with
	       it.  */
	    while ((status = mkdir_p (server_temp_dir)) == EEXIST)
	    {
		static const char suffix[] = "abcdefghijklmnopqrstuvwxyz";

		if (i >= sizeof suffix - 1) break;
		if (i == 0) p = server_temp_dir + strlen (server_temp_dir);
		p[0] = suffix[i++];
		p[1] = '\0';
	    }
	    if (status != 0)
	    {
		if (alloc_pending (80 + strlen (server_temp_dir)))
		    sprintf (pending_error_text,
			    "E can't create temporary directory %s",
			    server_temp_dir);
		pending_error = status;
	    }
#ifndef CHMOD_BROKEN
	    else if (chmod (server_temp_dir, S_IRWXU) < 0)
	    {
		int save_errno = errno;
		if (alloc_pending (80 + strlen (server_temp_dir)))
		    sprintf (pending_error_text,
"E cannot change permissions on temporary directory %s",
			     server_temp_dir);
		pending_error = save_errno;
	    }
#endif
	    else if (CVS_CHDIR (server_temp_dir) < 0)
	    {
		int save_errno = errno;
		if (alloc_pending (80 + strlen (server_temp_dir)))
		    sprintf (pending_error_text,
"E cannot change to temporary directory %s",
			     server_temp_dir);
		pending_error = save_errno;
	    }
	}
    }

    /* Now initialize our argument vector (for arguments from the client).  */

    /* Small for testing.  */
    argument_vector_size = 1;
    argument_vector = xmalloc (argument_vector_size * sizeof (char *));
    argument_count = 1;
    /* This gets printed if the client supports an option which the
       server doesn't, causing the server to print a usage message.
       FIXME: just a nit, I suppose, but the usage message the server
       prints isn't literally true--it suggests "cvs server" followed
       by options which are for a particular command.  Might be nice to
       say something like "client apparently supports an option not supported
       by this server" or something like that instead of usage message.  */
    error_prog_name = xmalloc (strlen (program_name) + 8);
    sprintf(error_prog_name, "%s server", program_name);
    argument_vector[0] = error_prog_name;

    while (1)
    {
	char *cmd, *orig_cmd;
	struct request *rq;
	int status;

	status = buf_read_line (buf_from_net, &cmd, NULL);
	if (status == -2)
	{
	    buf_output0 (buf_to_net, "E Fatal server error, aborting.\n\
error ENOMEM Virtual memory exhausted.\n");
	    break;
	}
	if (status != 0)
	    break;

	orig_cmd = cmd;
	for (rq = requests; rq->name != NULL; ++rq)
	    if (strncmp (cmd, rq->name, strlen (rq->name)) == 0)
	    {
		int len = strlen (rq->name);
		if (cmd[len] == '\0')
		    cmd += len;
		else if (cmd[len] == ' ')
		    cmd += len + 1;
		else
		    /*
		     * The first len characters match, but it's a different
		     * command.  e.g. the command is "cooperate" but we matched
		     * "co".
		     */
		    continue;

		if (!(rq->flags & RQ_ROOTLESS)
		    && current_parsed_root == NULL)
		{
		    /* For commands which change the way in which data
		       is sent and received, for example Gzip-stream,
		       this does the wrong thing.  Since the client
		       assumes that everything is being compressed,
		       unconditionally, there is no way to give this
		       error to the client without turning on
		       compression.  The obvious fix would be to make
		       Gzip-stream RQ_ROOTLESS (with the corresponding
		       change to the spec), and that might be a good
		       idea but then again I can see some settings in
		       CVSROOT about what compression level to allow.
		       I suppose a more baroque answer would be to
		       turn on compression (say, at level 1), just
		       enough to give the "Root request missing"
		       error.  For now we just lose.  */
		    if (alloc_pending (80))
			sprintf (pending_error_text,
				 "E Protocol error: Root request missing");
		}
		else
		    (*rq->func) (cmd);
		break;
	    }
	if (rq->name == NULL)
	{
	    if (!print_pending_error ())
	    {
		buf_output0 (buf_to_net, "error  unrecognized request `");
		buf_output0 (buf_to_net, cmd);
		buf_append_char (buf_to_net, '\'');
		buf_append_char (buf_to_net, '\n');
	    }
	}
	free (orig_cmd);
    }
    free (error_prog_name);

    /* We expect the client is done talking to us at this point.  If there is
     * any data in the buffer or on the network pipe, then something we didn't
     * prepare for is happening.
     */
    if (!buf_empty (buf_from_net))
    {
	/* Try to send the error message to the client, but also syslog it, in
	 * case the client isn't listening anymore.
	 */
#ifdef HAVE_SYSLOG_H
	/* FIXME: Can the IP address of the connecting client be retrieved
	 * and printed here?
	 */
	syslog (LOG_DAEMON | LOG_ERR, "Dying gasps received from client.");
#endif
	error (0, 0, "Dying gasps received from client.");
    }

    /* This command will actually close the network buffers.  */
    server_cleanup (0);
    return 0;
}



#if defined (HAVE_KERBEROS) || defined (AUTH_SERVER_SUPPORT) || defined (HAVE_GSSAPI)
static void switch_to_user PROTO((const char *, const char *));

static void
switch_to_user (cvs_username, username)
    const char *cvs_username; /* Only used for error messages. */
    const char *username;
{
    struct passwd *pw;

    pw = getpwnam (username);
    if (pw == NULL)
    {
	/* check_password contains a similar check, so this usually won't be
	   reached unless the CVS user is mapped to an invalid system user.  */

	printf ("E Fatal error, aborting.\n\
error 0 %s: no such system user\n", username);
	/* Don't worry about server_cleanup; server_active isn't set yet.  */
	error_exit ();
    }

    if (pw->pw_uid == 0)
    {
#ifdef HAVE_SYSLOG_H
	    /* FIXME: Can the IP address of the connecting client be retrieved
	     * and printed here?
	     */
	    syslog (LOG_DAEMON | LOG_ALERT,
		    "attempt to root from account: %s", cvs_username
		   );
#endif
        printf("error 0: root not allowed\n");
        error_exit ();
    }

#if HAVE_INITGROUPS
    if (initgroups (pw->pw_name, pw->pw_gid) < 0
#  ifdef EPERM
	/* At least on the system I tried, initgroups() only works as root.
	   But we do still want to report ENOMEM and whatever other
	   errors initgroups() might dish up.  */
	&& errno != EPERM
#  endif
	)
    {
	/* This could be a warning, but I'm not sure I see the point
	   in doing that instead of an error given that it would happen
	   on every connection.  We could log it somewhere and not tell
	   the user.  But at least for now make it an error.  */
	printf ("error 0 initgroups failed: %s\n", strerror (errno));
	/* Don't worry about server_cleanup; server_active isn't set yet.  */
	error_exit ();
    }
#endif /* HAVE_INITGROUPS */

#ifdef SETXID_SUPPORT
    /* honor the setgid bit iff set*/
    if (getgid() != getegid())
    {
	if (setgid (getegid ()) < 0)
	{
	    /* See comments at setuid call below for more discussion.  */
	    printf ("error 0 setgid failed: %s\n", strerror (errno));
	    /* Don't worry about server_cleanup;
	       server_active isn't set yet.  */
	    error_exit ();
	}
    }
    else
#endif
    {
	if (setgid (pw->pw_gid) < 0)
	{
	    /* See comments at setuid call below for more discussion.  */
	    printf ("error 0 setgid failed: %s\n", strerror (errno));
#ifdef HAVE_SYSLOG_H
	    syslog (LOG_DAEMON | LOG_ERR,
		    "setgid to %d failed (%m): real %d/%d, effective %d/%d ",
		    pw->pw_gid, getuid(), getgid(), geteuid(), getegid());
#endif
	    /* Don't worry about server_cleanup;
	       server_active isn't set yet.  */
	    error_exit ();
	}
    }

    if (setuid (pw->pw_uid) < 0)
    {
	/* Note that this means that if run as a non-root user,
	   CVSROOT/passwd must contain the user we are running as
	   (e.g. "joe:FsEfVcu:cvs" if run as "cvs" user).  This seems
	   cleaner than ignoring the error like CVS 1.10 and older but
	   it does mean that some people might need to update their
	   CVSROOT/passwd file.  */
	printf ("error 0 setuid failed: %s\n", strerror (errno));
#ifdef HAVE_SYSLOG_H
	    syslog (LOG_DAEMON | LOG_ERR,
		    "setuid to %d failed (%m): real %d/%d, effective %d/%d ",
		    pw->pw_uid, getuid(), getgid(), geteuid(), getegid());
#endif
	/* Don't worry about server_cleanup; server_active isn't set yet.  */
	error_exit ();
    }

    /* We don't want our umask to change file modes.  The modes should
       be set by the modes used in the repository, and by the umask of
       the client.  */
    umask (0);

#ifdef AUTH_SERVER_SUPPORT
    /* Make sure our CVS_Username has been set. */
    if (CVS_Username == NULL)
	CVS_Username = xstrdup (username);
#endif

#if HAVE_PUTENV
    /* Set LOGNAME, USER and CVS_USER in the environment, in case they
       are already set to something else.  */
    {
	char *env;

	env = xmalloc (sizeof "LOGNAME=" + strlen (username));
	(void) sprintf (env, "LOGNAME=%s", username);
	(void) putenv (env);

	env = xmalloc (sizeof "USER=" + strlen (username));
	(void) sprintf (env, "USER=%s", username);
	(void) putenv (env);

#ifdef AUTH_SERVER_SUPPORT
	env = xmalloc (sizeof "CVS_USER=" + strlen (CVS_Username));
	(void) sprintf (env, "CVS_USER=%s", CVS_Username);
	(void) putenv (env);
#endif
    }
#endif /* HAVE_PUTENV */
}
#endif

#ifdef AUTH_SERVER_SUPPORT

extern char *crypt PROTO((const char *, const char *));


/*
 * 0 means no entry found for this user.
 * 1 means entry found and password matches (or found password is empty)
 * 2 means entry found, but password does not match.
 *
 * If 1, host_user_ptr will be set to point at the system
 * username (i.e., the "real" identity, which may or may not be the
 * CVS username) of this user; caller may free this.  Global
 * CVS_Username will point at an allocated copy of cvs username (i.e.,
 * the username argument below).
 * kff todo: FIXME: last sentence is not true, it applies to caller.
 */
static int
check_repository_password (username, password, repository, host_user_ptr)
     char *username, *password, *repository, **host_user_ptr;
{
    int retval = 0;
    FILE *fp;
    char *filename;
    char *linebuf = NULL;
    size_t linebuf_len;
    int found_it = 0;
    int namelen;

    /* We don't use current_parsed_root->directory because it hasn't been
     * set yet -- our `repository' argument came from the authentication
     * protocol, not the regular CVS protocol.
     */

    filename = xmalloc (strlen (repository)
			+ 1
			+ strlen (CVSROOTADM)
			+ 1
			+ strlen (CVSROOTADM_PASSWD)
			+ 1);

    (void) sprintf (filename, "%s/%s/%s", repository,
		    CVSROOTADM, CVSROOTADM_PASSWD);

    fp = CVS_FOPEN (filename, "r");
    if (fp == NULL)
    {
	if (!existence_error (errno))
	    error (0, errno, "cannot open %s", filename);
	free (filename);
	return 0;
    }

    /* Look for a relevant line -- one with this user's name. */
    namelen = strlen (username);
    while (getline (&linebuf, &linebuf_len, fp) >= 0)
    {
	if ((strncmp (linebuf, username, namelen) == 0)
	    && (linebuf[namelen] == ':'))
	{
	    found_it = 1;
	    break;
	}
    }
    if (ferror (fp))
	error (0, errno, "cannot read %s", filename);
    if (fclose (fp) < 0)
	error (0, errno, "cannot close %s", filename);

    /* If found_it, then linebuf contains the information we need. */
    if (found_it)
    {
	char *found_password, *host_user_tmp;
	char *non_cvsuser_portion;

	/* We need to make sure lines such as
	 *
	 *    "username::sysuser\n"
	 *    "username:\n"
	 *    "username:  \n"
	 *
	 * all result in a found_password of NULL, but we also need to
	 * make sure that
	 *
	 *    "username:   :sysuser\n"
	 *    "username: <whatever>:sysuser\n"
	 *
	 * continues to result in an impossible password.  That way,
	 * an admin would be on safe ground by going in and tacking a
	 * space onto the front of a password to disable the account
	 * (a technique some people use to close accounts
	 * temporarily).
	 */

	/* Make `non_cvsuser_portion' contain everything after the CVS
	   username, but null out any final newline. */
	non_cvsuser_portion = linebuf + namelen;
	strtok (non_cvsuser_portion, "\n");

	/* If there's a colon now, we just want to inch past it. */
	if (strchr (non_cvsuser_portion, ':') == non_cvsuser_portion)
	    non_cvsuser_portion++;

	/* Okay, after this conditional chain, found_password and
	   host_user_tmp will have useful values: */

	if ((non_cvsuser_portion == NULL)
	    || (strlen (non_cvsuser_portion) == 0)
	    || ((strspn (non_cvsuser_portion, " \t"))
		== strlen (non_cvsuser_portion)))
	{
	    found_password = NULL;
	    host_user_tmp = NULL;
	}
	else if (strncmp (non_cvsuser_portion, ":", 1) == 0)
	{
	    found_password = NULL;
	    host_user_tmp = non_cvsuser_portion + 1;
	    if (strlen (host_user_tmp) == 0)
		host_user_tmp = NULL;
	}
	else
	{
	    found_password = strtok (non_cvsuser_portion, ":");
	    host_user_tmp = strtok (NULL, ":");
	}

	/* Of course, maybe there was no system user portion... */
	if (host_user_tmp == NULL)
	    host_user_tmp = username;

	/* Verify blank passwords directly, otherwise use crypt(). */
	if ((found_password == NULL)
	    || ((strcmp (found_password, crypt (password, found_password))
		 == 0)))
	{
	    /* Give host_user_ptr permanent storage. */
	    *host_user_ptr = xstrdup (host_user_tmp);
	    retval = 1;
	}
	else
	{
#ifdef LOG_AUTHPRIV
	syslog (LOG_AUTHPRIV | LOG_NOTICE,
		"password mismatch for %s in %s: %s vs. %s", username,
		repository, crypt(password, found_password), found_password);
#endif
	    *host_user_ptr = NULL;
	    retval	 = 2;
	}
    }
    else     /* Didn't find this user, so deny access. */
    {
	*host_user_ptr = NULL;
	retval = 0;
    }

    free (filename);
    if (linebuf)
	free (linebuf);

    return retval;
}



/* Return a hosting username if password matches, else NULL. */
static char *
check_password (username, password, repository)
    char *username, *password, *repository;
{
    int rc;
    char *host_user = NULL;
    char *found_passwd = NULL;
    struct passwd *pw;

    /* First we see if this user has a password in the CVS-specific
       password file.  If so, that's enough to authenticate with.  If
       not, we'll check /etc/passwd. */

    if (require_real_user)
	rc = 0;		/* "not found" */
    else
	rc = check_repository_password (username, password, repository,
				    &host_user);

    if (rc == 2)
	return NULL;

    if (rc == 1)
    {
	/* host_user already set by reference, so just return. */
	goto handle_return;
    }

    assert (rc == 0);

    if (!system_auth)
    {
	/* Note that the message _does_ distinguish between the case in
	   which we check for a system password and the case in which
	   we do not.  It is a real pain to track down why it isn't
	   letting you in if it won't say why, and I am not convinced
	   that the potential information disclosure to an attacker
	   outweighs this.  */
	printf ("error 0 no such user %s in CVSROOT/passwd\n", username);

	error_exit ();
    }

    /* No cvs password found, so try /etc/passwd. */

#ifdef HAVE_GETSPNAM
    {
	struct spwd *spw;

	spw = getspnam (username);
	if (spw != NULL)
	{
	    found_passwd = spw->sp_pwdp;
	}
    }
#endif

    if (found_passwd == NULL && (pw = getpwnam (username)) != NULL)
    {
	found_passwd = pw->pw_passwd;
    }

    if (found_passwd == NULL)
    {
	printf ("E Fatal error, aborting.\n\
error 0 %s: no such user\n", username);

	error_exit ();
    }

    /* Allow for dain bramaged HPUX passwd aging
     *  - Basically, HPUX adds a comma and some data
     *    about whether the passwd has expired or not
     *    on the end of the passwd field.
     *  - This code replaces the ',' with '\0'.
     *
     * FIXME - our workaround is brain damaged too.  I'm
     * guessing that HPUX WANTED other systems to think the
     * password was wrong so logins would fail if the
     * system didn't handle expired passwds and the passwd
     * might be expired.  I think the way to go here
     * is with PAM.
     */
    strtok (found_passwd, ",");

    if (*found_passwd)
    {
	/* user exists and has a password */
	if (strcmp (found_passwd, crypt (password, found_passwd)) == 0)
	{
	    host_user = xstrdup (username);
	}
	else
	{
	    host_user = NULL;
#ifdef LOG_AUTHPRIV
	    syslog (LOG_AUTHPRIV | LOG_NOTICE,
		    "password mismatch for %s: %s vs. %s", username,
		    crypt(password, found_passwd), found_passwd);
#endif
	}
	goto handle_return;
    }

    if (password && *password)
    {
	/* user exists and has no system password, but we got
	   one as parameter */
	host_user = xstrdup (username);
	goto handle_return;
    }

    /* user exists but has no password at all */
    host_user = NULL;
#ifdef LOG_AUTHPRIV
    syslog (LOG_AUTHPRIV | LOG_NOTICE,
	    "login refused for %s: user has no password", username);
#endif

handle_return:
    if (host_user)
    {
	/* Set CVS_Username here, in allocated space.
	   It might or might not be the same as host_user. */
	CVS_Username = xmalloc (strlen (username) + 1);
	strcpy (CVS_Username, username);
    }

    return host_user;
}

#endif /* AUTH_SERVER_SUPPORT */

#if defined (AUTH_SERVER_SUPPORT) || defined (HAVE_GSSAPI)

/* Read username and password from client (i.e., stdin).
   If correct, then switch to run as that user and send an ACK to the
   client via stdout, else send NACK and die. */
void
pserver_authenticate_connection ()
{
    char *tmp = NULL;
    size_t tmp_allocated = 0;
#ifdef AUTH_SERVER_SUPPORT
    char *repository = NULL;
    size_t repository_allocated = 0;
    char *username = NULL;
    size_t username_allocated = 0;
    char *password = NULL;
    size_t password_allocated = 0;

    char *host_user;
    char *descrambled_password;
#endif /* AUTH_SERVER_SUPPORT */
    int verify_and_exit = 0;

    /* The Authentication Protocol.  Client sends:
     *
     *   BEGIN AUTH REQUEST\n
     *   <REPOSITORY>\n
     *   <USERNAME>\n
     *   <PASSWORD>\n
     *   END AUTH REQUEST\n
     *
     * Server uses above information to authenticate, then sends
     *
     *   I LOVE YOU\n
     *
     * if it grants access, else
     *
     *   I HATE YOU\n
     *
     * if it denies access (and it exits if denying).
     *
     * When the client is "cvs login", the user does not desire actual
     * repository access, but would like to confirm the password with
     * the server.  In this case, the start and stop strings are
     *
     *   BEGIN VERIFICATION REQUEST\n
     *
     *	    and
     *
     *   END VERIFICATION REQUEST\n
     *
     * On a verification request, the server's responses are the same
     * (with the obvious semantics), but it exits immediately after
     * sending the response in both cases.
     *
     * Why is the repository sent?  Well, note that the actual
     * client/server protocol can't start up until authentication is
     * successful.  But in order to perform authentication, the server
     * needs to look up the password in the special CVS passwd file,
     * before trying /etc/passwd.  So the client transmits the
     * repository as part of the "authentication protocol".  The
     * repository will be redundantly retransmitted later, but that's no
     * big deal.
     */

#ifdef SO_KEEPALIVE
    /* Set SO_KEEPALIVE on the socket, so that we don't hang forever
       if the client dies while we are waiting for input.  */
    {
	int on = 1;

	if (setsockopt (STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE,
			   (char *) &on, sizeof on) < 0)
	{
#ifdef HAVE_SYSLOG_H
	    syslog (LOG_DAEMON | LOG_ERR, "error setting KEEPALIVE: %m");
#endif
	}
    }
#endif

    /* Make sure the protocol starts off on the right foot... */
    if (getline_safe (&tmp, &tmp_allocated, stdin, PATH_MAX) < 0)
	{
#ifdef HAVE_SYSLOG_H
	    syslog (LOG_DAEMON | LOG_NOTICE, "bad auth protocol start: EOF");
#endif
	    error (1, 0, "bad auth protocol start: EOF");
	}

    if (strcmp (tmp, "BEGIN VERIFICATION REQUEST\n") == 0)
	verify_and_exit = 1;
    else if (strcmp (tmp, "BEGIN AUTH REQUEST\n") == 0)
	;
    else if (strcmp (tmp, "BEGIN GSSAPI REQUEST\n") == 0)
    {
#ifdef HAVE_GSSAPI
	free (tmp);
	gserver_authenticate_connection ();
	return;
#else
	error (1, 0, "GSSAPI authentication not supported by this server");
#endif
    }
    else
	error (1, 0, "bad auth protocol start: %s", tmp);

#ifndef AUTH_SERVER_SUPPORT

    error (1, 0, "Password authentication not supported by this server");

#else /* AUTH_SERVER_SUPPORT */

    /* Get the three important pieces of information in order. */
    /* See above comment about error handling.  */
    getline_safe (&repository, &repository_allocated, stdin, PATH_MAX);
    getline_safe (&username, &username_allocated, stdin, PATH_MAX);
    getline_safe (&password, &password_allocated, stdin, PATH_MAX);

    /* Make them pure.
     *
     * We check that none of the lines were truncated by getnline in order
     * to be sure that we don't accidentally allow a blind DOS attack to
     * authenticate, however slim the odds of that might be.
     */
    if (!strip_trailing_newlines (repository)
	|| !strip_trailing_newlines (username)
	|| !strip_trailing_newlines (password))
	error (1, 0, "Maximum line length exceeded during authentication.");

    /* ... and make sure the protocol ends on the right foot. */
    /* See above comment about error handling.  */
    getline_safe (&tmp, &tmp_allocated, stdin, PATH_MAX);
    if (strcmp (tmp,
		verify_and_exit ?
		"END VERIFICATION REQUEST\n" : "END AUTH REQUEST\n")
	!= 0)
    {
	error (1, 0, "bad auth protocol end: %s", tmp);
    }
    if (!root_allow_ok (repository))
    {
	printf ("error 0 %s: no such repository\n", repository);
#ifdef HAVE_SYSLOG_H
	syslog (LOG_DAEMON | LOG_NOTICE, "login refused for %s", repository);
#endif
	goto i_hate_you;
    }

    /* OK, now parse the config file, so we can use it to control how
       to check passwords.  If there was an error parsing the config
       file, parse_config already printed an error.  We keep going.
       Why?  Because if we didn't, then there would be no way to check
       in a new CVSROOT/config file to fix the broken one!  */
    parse_config (repository);

    /* We need the real cleartext before we hash it. */
    descrambled_password = descramble (password);
    host_user = check_password (username, descrambled_password, repository);
    if (host_user == NULL)
    {
#ifdef HAVE_SYSLOG_H
	syslog (LOG_DAEMON | LOG_NOTICE, "login failure (for %s)", repository);
#endif
	memset (descrambled_password, 0, strlen (descrambled_password));
	free (descrambled_password);
    i_hate_you:
	printf ("I HATE YOU\n");
	fflush (stdout);

	/* Don't worry about server_cleanup, server_active isn't set
	   yet.  */
	error_exit ();
    }
    memset (descrambled_password, 0, strlen (descrambled_password));
    free (descrambled_password);

    /* Don't go any farther if we're just responding to "cvs login". */
    if (verify_and_exit)
    {
	printf ("I LOVE YOU\n");
	fflush (stdout);

	/* It's okay to skip rcs_cleanup() and Lock_Cleanup() here.  */

#ifdef SYSTEM_CLEANUP
	/* Hook for OS-specific behavior, for example socket subsystems on
	   NT and OS2 or dealing with windows and arguments on Mac.  */
	SYSTEM_CLEANUP ();
#endif

	exit (0);
    }

    /* Set Pserver_Repos so that we can check later that the same
       repository is sent in later client/server protocol. */
    Pserver_Repos = xmalloc (strlen (repository) + 1);
    strcpy (Pserver_Repos, repository);

    /* Switch to run as this user. */
    switch_to_user (username, host_user);
    free (host_user);
    free (tmp);
    free (repository);
    free (username);
    free (password);

    printf ("I LOVE YOU\n");
    fflush (stdout);
#endif /* AUTH_SERVER_SUPPORT */
}

#endif /* AUTH_SERVER_SUPPORT || HAVE_GSSAPI */


#ifdef HAVE_KERBEROS
void
kserver_authenticate_connection ()
{
    int status;
    char instance[INST_SZ];
    struct sockaddr_in peer;
    struct sockaddr_in laddr;
    int len;
    KTEXT_ST ticket;
    AUTH_DAT auth;
    char version[KRB_SENDAUTH_VLEN];
    char user[ANAME_SZ];

    strcpy (instance, "*");
    len = sizeof peer;
    if (getpeername (STDIN_FILENO, (struct sockaddr *) &peer, &len) < 0
	|| getsockname (STDIN_FILENO, (struct sockaddr *) &laddr,
			&len) < 0)
    {
	printf ("E Fatal error, aborting.\n\
error %s getpeername or getsockname failed\n", strerror (errno));

	error_exit ();
    }

#ifdef SO_KEEPALIVE
    /* Set SO_KEEPALIVE on the socket, so that we don't hang forever
       if the client dies while we are waiting for input.  */
    {
	int on = 1;

	if (setsockopt (STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE,
			   (char *) &on, sizeof on) < 0)
	{
#ifdef HAVE_SYSLOG_H
	    syslog (LOG_DAEMON | LOG_ERR, "error setting KEEPALIVE: %m");
#endif
	}
    }
#endif

    status = krb_recvauth (KOPT_DO_MUTUAL, STDIN_FILENO, &ticket, "rcmd",
			   instance, &peer, &laddr, &auth, "", sched,
			   version);
    if (status != KSUCCESS)
    {
	printf ("E Fatal error, aborting.\n\
error 0 kerberos: %s\n", krb_get_err_text(status));

	error_exit ();
    }

    memcpy (kblock, auth.session, sizeof (C_Block));

    /* Get the local name.  */
    status = krb_kntoln (&auth, user);
    if (status != KSUCCESS)
    {
	printf ("E Fatal error, aborting.\n\
error 0 kerberos: can't get local name: %s\n", krb_get_err_text(status));

	error_exit ();
    }

    /* Switch to run as this user. */
    switch_to_user ("Kerberos 4", user);
}
#endif /* HAVE_KERBEROS */

#ifdef HAVE_GSSAPI

#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN (256)
#endif

/* Authenticate a GSSAPI connection.  This is called from
   pserver_authenticate_connection, and it handles success and failure
   the same way.  */

static void
gserver_authenticate_connection ()
{
    char hostname[MAXHOSTNAMELEN];
    struct hostent *hp;
    gss_buffer_desc tok_in, tok_out;
    char buf[1024];
    char *credbuf;
    size_t credbuflen;
    OM_uint32 stat_min, ret;
    gss_name_t server_name, client_name;
    gss_cred_id_t server_creds;
    int nbytes;
    gss_OID mechid;

    gethostname (hostname, sizeof hostname);
    hp = gethostbyname (hostname);
    if (hp == NULL)
	error (1, 0, "can't get canonical hostname");

    sprintf (buf, "cvs@%s", hp->h_name);
    tok_in.value = buf;
    tok_in.length = strlen (buf);

    if (gss_import_name (&stat_min, &tok_in, GSS_C_NT_HOSTBASED_SERVICE,
			 &server_name) != GSS_S_COMPLETE)
	error (1, 0, "could not import GSSAPI service name %s", buf);

    /* Acquire the server credential to verify the client's
       authentication.  */
    if (gss_acquire_cred (&stat_min, server_name, 0, GSS_C_NULL_OID_SET,
			  GSS_C_ACCEPT, &server_creds,
			  NULL, NULL) != GSS_S_COMPLETE)
	error (1, 0, "could not acquire GSSAPI server credentials");

    gss_release_name (&stat_min, &server_name);

    /* The client will send us a two byte length followed by that many
       bytes.  */
    if (fread (buf, 1, 2, stdin) != 2)
	error (1, errno, "read of length failed");

    nbytes = ((buf[0] & 0xff) << 8) | (buf[1] & 0xff);
    if (nbytes <= sizeof buf)
    {
        credbuf = buf;
        credbuflen = sizeof buf;
    }
    else
    {
        credbuflen = nbytes;
        credbuf = xmalloc (credbuflen);
    }
    
    if (fread (credbuf, 1, nbytes, stdin) != nbytes)
	error (1, errno, "read of data failed");

    gcontext = GSS_C_NO_CONTEXT;
    tok_in.length = nbytes;
    tok_in.value = credbuf;

    if (gss_accept_sec_context (&stat_min,
				&gcontext,	/* context_handle */
				server_creds,	/* verifier_cred_handle */
				&tok_in,	/* input_token */
				NULL,		/* channel bindings */
				&client_name,	/* src_name */
				&mechid,	/* mech_type */
				&tok_out,	/* output_token */
				&ret,
				NULL,		/* ignore time_rec */
				NULL)		/* ignore del_cred_handle */
	!= GSS_S_COMPLETE)
    {
	error (1, 0, "could not verify credentials");
    }

    /* FIXME: Use Kerberos v5 specific code to authenticate to a user.
       We could instead use an authentication to access mapping.  */
    {
	krb5_context kc;
	krb5_principal p;
	gss_buffer_desc desc;

	krb5_init_context (&kc);
	if (gss_display_name (&stat_min, client_name, &desc,
			      &mechid) != GSS_S_COMPLETE
	    || krb5_parse_name (kc, ((gss_buffer_t) &desc)->value, &p) != 0
	    || krb5_aname_to_localname (kc, p, sizeof buf, buf) != 0
	    || krb5_kuserok (kc, p, buf) != TRUE)
	{
	    error (1, 0, "access denied");
	}
	krb5_free_principal (kc, p);
	krb5_free_context (kc);
    }

    if (tok_out.length != 0)
    {
	char cbuf[2];

	cbuf[0] = (tok_out.length >> 8) & 0xff;
	cbuf[1] = tok_out.length & 0xff;
	if (fwrite (cbuf, 1, 2, stdout) != 2
	    || (fwrite (tok_out.value, 1, tok_out.length, stdout)
		!= tok_out.length))
	    error (1, errno, "fwrite failed");
    }

    switch_to_user ("GSSAPI", buf);

    if (credbuf != buf)
        free (credbuf);

    printf ("I LOVE YOU\n");
    fflush (stdout);
}

#endif /* HAVE_GSSAPI */

#endif /* SERVER_SUPPORT */

#if defined (CLIENT_SUPPORT) || defined (SERVER_SUPPORT)

/* This global variable is non-zero if the user requests encryption on
   the command line.  */
int cvsencrypt;

/* This global variable is non-zero if the users requests stream
   authentication on the command line.  */
int cvsauthenticate;

#ifdef HAVE_GSSAPI

/* An buffer interface using GSSAPI.  This is built on top of a
   packetizing buffer.  */

/* This structure is the closure field of the GSSAPI translation
   routines.  */

struct cvs_gssapi_wrap_data
{
    /* The GSSAPI context.  */
    gss_ctx_id_t gcontext;
};

static int cvs_gssapi_wrap_input PROTO((void *, const char *, char *, int));
static int cvs_gssapi_wrap_output PROTO((void *, const char *, char *, int,
					 int *));

/* Create a GSSAPI wrapping buffer.  We use a packetizing buffer with
   GSSAPI wrapping routines.  */

struct buffer *
cvs_gssapi_wrap_buffer_initialize (buf, input, gcontext, memory)
     struct buffer *buf;
     int input;
     gss_ctx_id_t gcontext;
     void (*memory) PROTO((struct buffer *));
{
    struct cvs_gssapi_wrap_data *gd;

    gd = (struct cvs_gssapi_wrap_data *) xmalloc (sizeof *gd);
    gd->gcontext = gcontext;

    return (packetizing_buffer_initialize
	    (buf,
	     input ? cvs_gssapi_wrap_input : NULL,
	     input ? NULL : cvs_gssapi_wrap_output,
	     gd,
	     memory));
}

/* Unwrap data using GSSAPI.  */

static int
cvs_gssapi_wrap_input (fnclosure, input, output, size)
     void *fnclosure;
     const char *input;
     char *output;
     int size;
{
    struct cvs_gssapi_wrap_data *gd =
	(struct cvs_gssapi_wrap_data *) fnclosure;
    gss_buffer_desc inbuf, outbuf;
    OM_uint32 stat_min;
    int conf;

    inbuf.value = (void *) input;
    inbuf.length = size;

    if (gss_unwrap (&stat_min, gd->gcontext, &inbuf, &outbuf, &conf, NULL)
	!= GSS_S_COMPLETE)
    {
	error (1, 0, "gss_unwrap failed");
    }

    if (outbuf.length > size)
	abort ();

    memcpy (output, outbuf.value, outbuf.length);

    /* The real packet size is stored in the data, so we don't need to
       remember outbuf.length.  */

    gss_release_buffer (&stat_min, &outbuf);

    return 0;
}

/* Wrap data using GSSAPI.  */

static int
cvs_gssapi_wrap_output (fnclosure, input, output, size, translated)
     void *fnclosure;
     const char *input;
     char *output;
     int size;
     int *translated;
{
    struct cvs_gssapi_wrap_data *gd =
	(struct cvs_gssapi_wrap_data *) fnclosure;
    gss_buffer_desc inbuf, outbuf;
    OM_uint32 stat_min;
    int conf_req, conf;

    inbuf.value = (void *) input;
    inbuf.length = size;

#ifdef ENCRYPTION
    conf_req = cvs_gssapi_encrypt;
#else
    conf_req = 0;
#endif

    if (gss_wrap (&stat_min, gd->gcontext, conf_req, GSS_C_QOP_DEFAULT,
		  &inbuf, &conf, &outbuf) != GSS_S_COMPLETE)
	error (1, 0, "gss_wrap failed");

    /* The packetizing buffer only permits us to add 100 bytes.
       FIXME: I don't know what, if anything, is guaranteed by GSSAPI.
       This may need to be increased for a different GSSAPI
       implementation, or we may need a different algorithm.  */
    if (outbuf.length > size + 100)
	abort ();

    memcpy (output, outbuf.value, outbuf.length);

    *translated = outbuf.length;

    gss_release_buffer (&stat_min, &outbuf);

    return 0;
}

#endif /* HAVE_GSSAPI */

#ifdef ENCRYPTION

#ifdef HAVE_KERBEROS

/* An encryption interface using Kerberos.  This is built on top of a
   packetizing buffer.  */

/* This structure is the closure field of the Kerberos translation
   routines.  */

struct krb_encrypt_data
{
    /* The Kerberos key schedule.  */
    Key_schedule sched;
    /* The Kerberos DES block.  */
    C_Block block;
};

static int krb_encrypt_input PROTO((void *, const char *, char *, int));
static int krb_encrypt_output PROTO((void *, const char *, char *, int,
				     int *));

/* Create a Kerberos encryption buffer.  We use a packetizing buffer
   with Kerberos encryption translation routines.  */

struct buffer *
krb_encrypt_buffer_initialize (buf, input, sched, block, memory)
     struct buffer *buf;
     int input;
     Key_schedule sched;
     C_Block block;
     void (*memory) PROTO((struct buffer *));
{
    struct krb_encrypt_data *kd;

    kd = (struct krb_encrypt_data *) xmalloc (sizeof *kd);
    memcpy (kd->sched, sched, sizeof (Key_schedule));
    memcpy (kd->block, block, sizeof (C_Block));

    return packetizing_buffer_initialize (buf,
					  input ? krb_encrypt_input : NULL,
					  input ? NULL : krb_encrypt_output,
					  kd,
					  memory);
}

/* Decrypt Kerberos data.  */

static int
krb_encrypt_input (fnclosure, input, output, size)
     void *fnclosure;
     const char *input;
     char *output;
     int size;
{
    struct krb_encrypt_data *kd = (struct krb_encrypt_data *) fnclosure;
    int tcount;

    des_cbc_encrypt ((C_Block *) input, (C_Block *) output,
		     size, kd->sched, &kd->block, 0);

    /* SIZE is the size of the buffer, which is set by the encryption
       routine.  The packetizing buffer will arrange for the first two
       bytes in the decrypted buffer to be the real (unaligned)
       length.  As a safety check, make sure that the length in the
       buffer corresponds to SIZE.  Note that the length in the buffer
       is just the length of the data.  We must add 2 to account for
       the buffer count itself.  */
    tcount = ((output[0] & 0xff) << 8) + (output[1] & 0xff);
    if (((tcount + 2 + 7) & ~7) != size)
      error (1, 0, "Decryption failure");

    return 0;
}

/* Encrypt Kerberos data.  */

static int
krb_encrypt_output (fnclosure, input, output, size, translated)
     void *fnclosure;
     const char *input;
     char *output;
     int size;
     int *translated;
{
    struct krb_encrypt_data *kd = (struct krb_encrypt_data *) fnclosure;
    int aligned;

    /* For security against a known plaintext attack, we should
       initialize any padding bytes to random values.  Instead, we
       just pick up whatever is on the stack, which is at least better
       than using zero.  */

    /* Align SIZE to an 8 byte boundary.  Note that SIZE includes the
       two byte buffer count at the start of INPUT which was added by
       the packetizing buffer.  */
    aligned = (size + 7) & ~7;

    /* We use des_cbc_encrypt rather than krb_mk_priv because the
       latter sticks a timestamp in the block, and krb_rd_priv expects
       that timestamp to be within five minutes of the current time.
       Given the way the CVS server buffers up data, that can easily
       fail over a long network connection.  We trust krb_recvauth to
       guard against a replay attack.  */

    des_cbc_encrypt ((C_Block *) input, (C_Block *) output, aligned,
		     kd->sched, &kd->block, 1);

    *translated = aligned;

    return 0;
}

#endif /* HAVE_KERBEROS */
#endif /* ENCRYPTION */
#endif /* defined (CLIENT_SUPPORT) || defined (SERVER_SUPPORT) */

/* Output LEN bytes at STR.  If LEN is zero, then output up to (not including)
   the first '\0' byte.  */

void
cvs_output (str, len)
    const char *str;
    size_t len;
{
    if (len == 0)
	len = strlen (str);
#ifdef SERVER_SUPPORT
    if (error_use_protocol && buf_to_net != NULL)
    {
	buf_output (saved_output, str, len);
	buf_copy_lines (buf_to_net, saved_output, 'M');
    }
    else if (server_active && protocol != NULL)
    {
	buf_output (saved_output, str, len);
	buf_copy_lines (protocol, saved_output, 'M');
	buf_send_counted (protocol);
    }
    else
#endif
    {
	size_t written;
	size_t to_write = len;
	const char *p = str;

	/* Local users that do 'cvs status 2>&1' on a local repository
	   may see the informational messages out-of-order with the
	   status messages unless we use the fflush (stderr) here. */
	fflush (stderr);

	while (to_write > 0)
	{
	    written = fwrite (p, 1, to_write, stdout);
	    if (written == 0)
		break;
	    p += written;
	    to_write -= written;
	}
    }
}

/* Output LEN bytes at STR in binary mode.  If LEN is zero, then
   output zero bytes.  */

void
cvs_output_binary (str, len)
    char *str;
    size_t len;
{
#ifdef SERVER_SUPPORT
    if (error_use_protocol || server_active)
    {
	struct buffer *buf;
	char size_text[40];

	if (error_use_protocol)
	    buf = buf_to_net;
	else
	    buf = protocol;

	if (!supported_response ("Mbinary"))
	{
	    error (0, 0, "\
this client does not support writing binary files to stdout");
	    return;
	}

	buf_output0 (buf, "Mbinary\012");
	sprintf (size_text, "%lu\012", (unsigned long) len);
	buf_output0 (buf, size_text);

	/* Not sure what would be involved in using buf_append_data here
	   without stepping on the toes of our caller (which is responsible
	   for the memory allocation of STR).  */
	buf_output (buf, str, len);

	if (!error_use_protocol)
	    buf_send_counted (protocol);
    }
    else
#endif
    {
	size_t written;
	size_t to_write = len;
	const char *p = str;
#ifdef USE_SETMODE_STDOUT
	int oldmode;
#endif

	/* Local users that do 'cvs status 2>&1' on a local repository
	   may see the informational messages out-of-order with the
	   status messages unless we use the fflush (stderr) here. */
	fflush (stderr);

#ifdef USE_SETMODE_STDOUT
	/* It is possible that this should be the same ifdef as
	   USE_SETMODE_BINARY but at least for the moment we keep them
	   separate.  Mostly this is just laziness and/or a question
	   of what has been tested where.  Also there might be an
	   issue of setmode vs. _setmode.  */
	/* The Windows doc says to call setmode only right after startup.
	   I assume that what they are talking about can also be helped
	   by flushing the stream before changing the mode.  */
	fflush (stdout);
	oldmode = _setmode (_fileno (stdout), OPEN_BINARY);
	if (oldmode < 0)
	    error (0, errno, "failed to setmode on stdout");
#endif

	while (to_write > 0)
	{
	    written = fwrite (p, 1, to_write, stdout);
	    if (written == 0)
		break;
	    p += written;
	    to_write -= written;
	}
#ifdef USE_SETMODE_STDOUT
	fflush (stdout);
	if (_setmode (_fileno (stdout), oldmode) != OPEN_BINARY)
	    error (0, errno, "failed to setmode on stdout");
#endif
    }
}



/* Like CVS_OUTPUT but output is for stderr not stdout.  */
void
cvs_outerr (str, len)
    const char *str;
    size_t len;
{
    if (len == 0)
	len = strlen (str);
#ifdef SERVER_SUPPORT
    if (error_use_protocol)
    {
	buf_output (saved_outerr, str, len);
	buf_copy_lines (buf_to_net, saved_outerr, 'E');
    }
    else if (server_active)
    {
	buf_output (saved_outerr, str, len);
	buf_copy_lines (protocol, saved_outerr, 'E');
	buf_send_counted (protocol);
    }
    else
#endif
    {
	size_t written;
	size_t to_write = len;
	const char *p = str;

	/* Make sure that output appears in order if stdout and stderr
	   point to the same place.  For the server case this is taken
	   care of by the fact that saved_outerr always holds less
	   than a line.  */
	fflush (stdout);

	while (to_write > 0)
	{
	    written = fwrite (p, 1, to_write, stderr);
	    if (written == 0)
		break;
	    p += written;
	    to_write -= written;
	}
    }
}



/* Flush stderr.  stderr is normally flushed automatically, of course,
   but this function is used to flush information from the server back
   to the client.  */
void
cvs_flusherr ()
{
#ifdef SERVER_SUPPORT
    if (error_use_protocol)
    {
	/* skip the actual stderr flush in this case since the parent process
	 * on the server should only be writing to stdout anyhow
	 */
	/* Flush what we can to the network, but don't block.  */
	buf_flush (buf_to_net, 0);
    }
    else if (server_active)
    {
	/* make sure stderr is flushed before we send the flush count on the
	 * protocol pipe
	 */
	fflush (stderr);
	/* Send a special count to tell the parent to flush.  */
	buf_send_special_count (protocol, -2);
    }
    else
#endif
	fflush (stderr);
}



/* Make it possible for the user to see what has been written to
   stdout (it is up to the implementation to decide exactly how far it
   should go to ensure this).  */
void
cvs_flushout ()
{
#ifdef SERVER_SUPPORT
    if (error_use_protocol)
    {
	/* Flush what we can to the network, but don't block.  */
	buf_flush (buf_to_net, 0);
    }
    else if (server_active)
    {
	/* Just do nothing.  This is because the code which
	   cvs_flushout replaces, setting stdout to line buffering in
	   main.c, didn't get called in the server child process.  But
	   in the future it is quite plausible that we'll want to make
	   this case work analogously to cvs_flusherr.

	   FIXME - DRP - I tried to implement this and triggered the following
	   error: "Protocol error: uncounted data discarded".  I don't need
	   this feature right now, so I'm not going to bother with it yet.
	 */
	buf_send_special_count (protocol, -1);
    }
    else
#endif
	fflush (stdout);
}

/* Output TEXT, tagging it according to TAG.  There are lots more
   details about what TAG means in cvsclient.texi but for the simple
   case (e.g. non-client/server), TAG is just "newline" to output a
   newline (in which case TEXT must be NULL), and any other tag to
   output normal text.

   Note that there is no way to output either \0 or \n as part of TEXT.  */

void
cvs_output_tagged (tag, text)
    const char *tag;
    const char *text;
{
    if (text != NULL && strchr (text, '\n') != NULL)
	/* Uh oh.  The protocol has no way to cope with this.  For now
	   we dump core, although that really isn't such a nice
	   response given that this probably can be caused by newlines
	   in filenames and other causes other than bugs in CVS.  Note
	   that we don't want to turn this into "MT newline" because
	   this case is a newline within a tagged item, not a newline
	   as extraneous sugar for the user.  */
	assert (0);

    /* Start and end tags don't take any text, per cvsclient.texi.  */
    if (tag[0] == '+' || tag[0] == '-')
	assert (text == NULL);

#ifdef SERVER_SUPPORT
    if (server_active && supported_response ("MT"))
    {
	struct buffer *buf;

	if (error_use_protocol)
	    buf = buf_to_net;
	else
	    buf = protocol;

	buf_output0 (buf, "MT ");
	buf_output0 (buf, tag);
	if (text != NULL)
	{
	    buf_output (buf, " ", 1);
	    buf_output0 (buf, text);
	}
	buf_output (buf, "\n", 1);

	if (!error_use_protocol)
	    buf_send_counted (protocol);
    }
    else
#endif
    {
	if (strcmp (tag, "newline") == 0)
	    cvs_output ("\n", 1);
	else if (text != NULL)
	    cvs_output (text, 0);
    }
}
