emacs/lib-src/movemail.c

/* movemail foo bar -- move file foo to file bar,
   locking file foo the way /bin/mail respects.
   Copyright (C) 1986, 1992, 1993, 1994, 1996, 1999, 2001, 2002, 2003, 2004,
                 2005, 2006, 2007, 2008, 2009, 2010, 2011  Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs 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 3 of the License, or
(at your option) any later version.

GNU Emacs 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.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */


/* Important notice: defining MAIL_USE_FLOCK or MAIL_USE_LOCKF *will
   cause loss of mail* if you do it on a system that does not normally
   use flock as its way of interlocking access to inbox files.  The
   setting of MAIL_USE_FLOCK and MAIL_USE_LOCKF *must agree* with the
   system's own conventions.  It is not a choice that is up to you.

   So, if your system uses lock files rather than flock, then the only way
   you can get proper operation is to enable movemail to write lockfiles there.
   This means you must either give that directory access modes
   that permit everyone to write lockfiles in it, or you must make movemail
   a setuid or setgid program.  */

/*
 * Modified January, 1986 by Michael R. Gretzinger (Project Athena)
 *
 * Added POP (Post Office Protocol) service.  When compiled -DMAIL_USE_POP
 * movemail will accept input filename arguments of the form
 * "po:username".  This will cause movemail to open a connection to
 * a pop server running on $MAILHOST (environment variable).  Movemail
 * must be setuid to root in order to work with POP.
 *
 * New module: popmail.c
 * Modified routines:
 *	main - added code within #ifdef MAIL_USE_POP; added setuid (getuid ())
 *		after POP code.
 * New routines in movemail.c:
 *	get_errmsg - return pointer to system error message
 *
 * Modified August, 1993 by Jonathan Kamens (OpenVision Technologies)
 *
 * Move all of the POP code into a separate file, "pop.c".
 * Use strerror instead of get_errmsg.
 *
 */

#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <stdio.h>
#include <errno.h>
#include <time.h>

#include <getopt.h>
#include <unistd.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include "syswait.h"
#ifdef MAIL_USE_POP
#include "pop.h"
#endif

#ifdef MSDOS
#undef access
#endif /* MSDOS */

#ifndef DIRECTORY_SEP
#define DIRECTORY_SEP '/'
#endif
#ifndef IS_DIRECTORY_SEP
#define IS_DIRECTORY_SEP(_c_) ((_c_) == DIRECTORY_SEP)
#endif

#ifdef WINDOWSNT
#include "ntlib.h"
#undef access
#undef unlink
#define fork() 0
#define wait(var) (*(var) = 0)
/* Unfortunately, Samba doesn't seem to properly lock Unix files even
   though the locking call succeeds (and indeed blocks local access from
   other NT programs).  If you have direct file access using an NFS
   client or something other than Samba, the locking call might work
   properly - make sure it does before you enable this!

   [18-Feb-97 andrewi] I now believe my comment above to be incorrect,
   since it was based on a misunderstanding of how locking calls are
   implemented and used on Unix.  */
//#define DISABLE_DIRECT_ACCESS

#include <fcntl.h>
#endif /* WINDOWSNT */

#ifndef F_OK
#define F_OK 0
#define X_OK 1
#define W_OK 2
#define R_OK 4
#endif

#ifdef WINDOWSNT
#include <sys/locking.h>
#endif

#ifdef MAIL_USE_LOCKF
#define MAIL_USE_SYSTEM_LOCK
#endif

#ifdef MAIL_USE_FLOCK
#define MAIL_USE_SYSTEM_LOCK
#endif

#ifdef MAIL_USE_MMDF
extern int lk_open (), lk_close ();
#endif

#if !defined (MAIL_USE_SYSTEM_LOCK) && !defined (MAIL_USE_MMDF) && \
	(defined (HAVE_LIBMAIL) || defined (HAVE_LIBLOCKFILE)) && \
        defined (HAVE_MAILLOCK_H)
#include <maillock.h>
/* We can't use maillock unless we know what directory system mail
   files appear in. */
#ifdef MAILDIR
#define MAIL_USE_MAILLOCK
static char *mail_spool_name ();
#endif
#endif

#ifndef HAVE_STRERROR
char *strerror (int);
#endif

static void fatal (const char *s1, const char *s2, const char *s3) NO_RETURN;
static void error (const char *s1, const char *s2, const char *s3);
static void pfatal_with_name (char *name) NO_RETURN;
static void pfatal_and_delete (char *name) NO_RETURN;
static char *concat (const char *s1, const char *s2, const char *s3);
static long *xmalloc (unsigned int size);
#ifdef MAIL_USE_POP
static int popmail (char *mailbox, char *outfile, int preserve, char *password, int reverse_order);
static int pop_retr (popserver server, int msgno, FILE *arg);
static int mbx_write (char *line, int len, FILE *mbf);
static int mbx_delimit_begin (FILE *mbf);
static int mbx_delimit_end (FILE *mbf);
#endif

/* Nonzero means this is name of a lock file to delete on fatal error.  */
char *delete_lockname;

int
main (int argc, char **argv)
{
  char *inname, *outname;
  int indesc, outdesc;
  ssize_t nread;
  int status;
  int c, preserve_mail = 0;

#ifndef MAIL_USE_SYSTEM_LOCK
  struct stat st;
  long now;
  int tem;
  char *lockname, *p;
  char *tempname;
  int desc;
#endif /* not MAIL_USE_SYSTEM_LOCK */

#ifdef MAIL_USE_MAILLOCK
  char *spool_name;
#endif

#ifdef MAIL_USE_POP
  int pop_reverse_order = 0;
# define ARGSTR "pr"
#else /* ! MAIL_USE_POP */
# define ARGSTR "p"
#endif /* MAIL_USE_POP */

  uid_t real_gid = getgid();
  uid_t priv_gid = getegid();

#ifdef WINDOWSNT
  /* Ensure all file i/o is in binary mode. */
  _fmode = _O_BINARY;
#endif

  delete_lockname = 0;

  while ((c = getopt (argc, argv, ARGSTR)) != EOF)
    {
      switch (c) {
#ifdef MAIL_USE_POP
      case 'r':
	pop_reverse_order = 1;
	break;
#endif
      case 'p':
	preserve_mail++;
	break;
      default:
	exit (EXIT_FAILURE);
      }
    }

  if (
#ifdef MAIL_USE_POP
      (argc - optind < 2) || (argc - optind > 3)
#else
      (argc - optind != 2)
#endif
      )
    {
#ifdef MAIL_USE_POP
      fprintf (stderr, "Usage: movemail [-p] [-r] inbox destfile%s\n",
	       " [POP-password]");
#else
      fprintf (stderr, "Usage: movemail [-p] inbox destfile%s\n", "");
#endif
      exit (EXIT_FAILURE);
    }

  inname = argv[optind];
  outname = argv[optind+1];

#ifdef MAIL_USE_MMDF
  mmdf_init (argv[0]);
#endif

  if (*outname == 0)
    fatal ("Destination file name is empty", 0, 0);

#ifdef MAIL_USE_POP
  if (!strncmp (inname, "po:", 3))
    {
      int status;

      status = popmail (inname + 3, outname, preserve_mail,
			(argc - optind == 3) ? argv[optind+2] : NULL,
			pop_reverse_order);
      exit (status);
    }

  if (setuid (getuid ()) < 0)
    fatal ("Failed to drop privileges", 0, 0);

#endif /* MAIL_USE_POP */

#ifndef DISABLE_DIRECT_ACCESS
#ifndef MAIL_USE_MMDF
#ifndef MAIL_USE_SYSTEM_LOCK
#ifdef MAIL_USE_MAILLOCK
  spool_name = mail_spool_name (inname);
  if (! spool_name)
#endif
    {
      /* Use a lock file named after our first argument with .lock appended:
	 If it exists, the mail file is locked.  */
      /* Note: this locking mechanism is *required* by the mailer
	 (on systems which use it) to prevent loss of mail.

	 On systems that use a lock file, extracting the mail without locking
	 WILL occasionally cause loss of mail due to timing errors!

	 So, if creation of the lock file fails
	 due to access permission on the mail spool directory,
	 you simply MUST change the permission
	 and/or make movemail a setgid program
	 so it can create lock files properly.

	 You might also wish to verify that your system is one
	 which uses lock files for this purpose.  Some systems use other methods.

	 If your system uses the `flock' system call for mail locking,
	 define MAIL_USE_SYSTEM_LOCK in config.h or the s-*.h file
	 and recompile movemail.  If the s- file for your system
	 should define MAIL_USE_SYSTEM_LOCK but does not, send a bug report
	 to bug-gnu-emacs@prep.ai.mit.edu so we can fix it.  */

      lockname = concat (inname, ".lock", "");
      tempname = (char *) xmalloc (strlen (inname) + strlen ("EXXXXXX") + 1);
      strcpy (tempname, inname);
      p = tempname + strlen (tempname);
      while (p != tempname && !IS_DIRECTORY_SEP (p[-1]))
	p--;
      *p = 0;
      strcpy (p, "EXXXXXX");
      mktemp (tempname);
      unlink (tempname);

      while (1)
	{
	  /* Create the lock file, but not under the lock file name.  */
	  /* Give up if cannot do that.  */
	  desc = open (tempname, O_WRONLY | O_CREAT | O_EXCL, 0666);
	  if (desc < 0)
	    {
	      char *message = (char *) xmalloc (strlen (tempname) + 50);
	      sprintf (message, "creating %s, which would become the lock file",
		       tempname);
	      pfatal_with_name (message);
	    }
	  close (desc);

	  tem = link (tempname, lockname);

#ifdef EPERM
	  if (tem < 0 && errno == EPERM)
	    fatal ("Unable to create hard link between %s and %s",
		   tempname, lockname);
#endif

	  unlink (tempname);
	  if (tem >= 0)
	    break;
	  sleep (1);

	  /* If lock file is five minutes old, unlock it.
	     Five minutes should be good enough to cope with crashes
	     and wedgitude, and long enough to avoid being fooled
	     by time differences between machines.  */
	  if (stat (lockname, &st) >= 0)
	    {
	      now = time (0);
	      if (st.st_ctime < now - 300)
		unlink (lockname);
	    }
	}

      delete_lockname = lockname;
    }
#endif /* not MAIL_USE_SYSTEM_LOCK */
#endif /* not MAIL_USE_MMDF */

  if (fork () == 0)
    {
      int lockcount = 0;
      int status = 0;
#if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
      time_t touched_lock, now;
#endif

      if (setuid (getuid ()) < 0 || setregid (-1, real_gid) < 0)
	fatal ("Failed to drop privileges", 0, 0);

#ifndef MAIL_USE_MMDF
#ifdef MAIL_USE_SYSTEM_LOCK
      indesc = open (inname, O_RDWR);
#else  /* if not MAIL_USE_SYSTEM_LOCK */
      indesc = open (inname, O_RDONLY);
#endif /* not MAIL_USE_SYSTEM_LOCK */
#else  /* MAIL_USE_MMDF */
      indesc = lk_open (inname, O_RDONLY, 0, 0, 10);
#endif /* MAIL_USE_MMDF */

      if (indesc < 0)
	pfatal_with_name (inname);

#ifdef BSD_SYSTEM
      /* In case movemail is setuid to root, make sure the user can
	 read the output file.  */
      /* This is desirable for all systems
	 but I don't want to assume all have the umask system call */
      umask (umask (0) & 0333);
#endif /* BSD_SYSTEM */
      outdesc = open (outname, O_WRONLY | O_CREAT | O_EXCL, 0666);
      if (outdesc < 0)
	pfatal_with_name (outname);

      if (setregid (-1, priv_gid) < 0)
	fatal ("Failed to regain privileges", 0, 0);

      /* This label exists so we can retry locking
	 after a delay, if it got EAGAIN or EBUSY.  */
    retry_lock:

      /* Try to lock it.  */
#ifdef MAIL_USE_MAILLOCK
      if (spool_name)
	{
	  /* The "0 - " is to make it a negative number if maillock returns
	     non-zero. */
	  status = 0 - maillock (spool_name, 1);
#ifdef HAVE_TOUCHLOCK
	  touched_lock = time (0);
#endif
	  lockcount = 5;
	}
      else
#endif /* MAIL_USE_MAILLOCK */
	{
#ifdef MAIL_USE_SYSTEM_LOCK
#ifdef MAIL_USE_LOCKF
	  status = lockf (indesc, F_LOCK, 0);
#else /* not MAIL_USE_LOCKF */
#ifdef WINDOWSNT
	  status = locking (indesc, LK_RLCK, -1L);
#else
	  status = flock (indesc, LOCK_EX);
#endif
#endif /* not MAIL_USE_LOCKF */
#endif /* MAIL_USE_SYSTEM_LOCK */
	}

      /* If it fails, retry up to 5 times
	 for certain failure codes.  */
      if (status < 0)
	{
	  if (++lockcount <= 5)
	    {
#ifdef EAGAIN
	      if (errno == EAGAIN)
		{
		  sleep (1);
		  goto retry_lock;
		}
#endif
#ifdef EBUSY
	      if (errno == EBUSY)
		{
		  sleep (1);
		  goto retry_lock;
		}
#endif
	    }

	  pfatal_with_name (inname);
	}

      {
	char buf[1024];

	while (1)
	  {
	    nread = read (indesc, buf, sizeof buf);
	    if (nread < 0)
	      pfatal_with_name (inname);
	    if (nread != write (outdesc, buf, nread))
	      {
		int saved_errno = errno;
		unlink (outname);
		errno = saved_errno;
		pfatal_with_name (outname);
	      }
	    if (nread < sizeof buf)
	      break;
#if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
	    if (spool_name)
	      {
		now = time (0);
		if (now - touched_lock > 60)
		  {
		    touchlock ();
		    touched_lock = now;
		  }
	      }
#endif /* MAIL_USE_MAILLOCK */
	  }
      }

#ifdef BSD_SYSTEM
      if (fsync (outdesc) < 0)
	pfatal_and_delete (outname);
#endif

      /* Prevent symlink attacks truncating other users' mailboxes */
      if (setregid (-1, real_gid) < 0)
	fatal ("Failed to drop privileges", 0, 0);

      /* Check to make sure no errors before we zap the inbox.  */
      if (close (outdesc) != 0)
	pfatal_and_delete (outname);

#ifdef MAIL_USE_SYSTEM_LOCK
      if (! preserve_mail)
	{
	  if (ftruncate (indesc, 0L) != 0)
	    pfatal_with_name (inname);
	}
#endif /* MAIL_USE_SYSTEM_LOCK */

#ifdef MAIL_USE_MMDF
      lk_close (indesc, 0, 0, 0);
#else
      close (indesc);
#endif

#ifndef MAIL_USE_SYSTEM_LOCK
      if (! preserve_mail)
	{
	  /* Delete the input file; if we can't, at least get rid of its
	     contents.  */
#ifdef MAIL_UNLINK_SPOOL
	  /* This is generally bad to do, because it destroys the permissions
	     that were set on the file.  Better to just empty the file.  */
	  if (unlink (inname) < 0 && errno != ENOENT)
#endif /* MAIL_UNLINK_SPOOL */
	    creat (inname, 0600);
	}
#endif /* not MAIL_USE_SYSTEM_LOCK */

      /* End of mailbox truncation */
      if (setregid (-1, priv_gid) < 0)
	fatal ("Failed to regain privileges", 0, 0);

#ifdef MAIL_USE_MAILLOCK
      /* This has to occur in the child, i.e., in the process that
         acquired the lock! */
      if (spool_name)
	mailunlock ();
#endif
      exit (EXIT_SUCCESS);
    }

  wait (&status);
  if (!WIFEXITED (status))
    exit (EXIT_FAILURE);
  else if (WRETCODE (status) != 0)
    exit (WRETCODE (status));

#if !defined (MAIL_USE_MMDF) && !defined (MAIL_USE_SYSTEM_LOCK)
#ifdef MAIL_USE_MAILLOCK
  if (! spool_name)
#endif /* MAIL_USE_MAILLOCK */
    unlink (lockname);
#endif /* not MAIL_USE_MMDF and not MAIL_USE_SYSTEM_LOCK */

#endif /* ! DISABLE_DIRECT_ACCESS */

  return EXIT_SUCCESS;
}

#ifdef MAIL_USE_MAILLOCK
/* This function uses stat to confirm that the mail directory is
   identical to the directory of the input file, rather than just
   string-comparing the two paths, because one or both of them might
   be symbolic links pointing to some other directory. */
static char *
mail_spool_name (char *inname)
{
  struct stat stat1, stat2;
  char *indir, *fname;
  int status;

  if (! (fname = strrchr (inname, '/')))
    return NULL;

  fname++;

  if (stat (MAILDIR, &stat1) < 0)
    return NULL;

  indir = (char *) xmalloc (fname - inname + 1);
  strncpy (indir, inname, fname - inname);
  indir[fname-inname] = '\0';


  status = stat (indir, &stat2);

  free (indir);

  if (status < 0)
    return NULL;

  if (stat1.st_dev == stat2.st_dev
      && stat1.st_ino == stat2.st_ino)
    return fname;

  return NULL;
}
#endif /* MAIL_USE_MAILLOCK */

/* Print error message and exit.  */

static void
fatal (const char *s1, const char *s2, const char *s3)
{
  if (delete_lockname)
    unlink (delete_lockname);
  error (s1, s2, s3);
  exit (EXIT_FAILURE);
}

/* Print error message.  `s1' is printf control string, `s2' and `s3'
   are args for it or null. */

static void
error (const char *s1, const char *s2, const char *s3)
{
  fprintf (stderr, "movemail: ");
  if (s3)
    fprintf (stderr, s1, s2, s3);
  else if (s2)
    fprintf (stderr, s1, s2);
  else
    fprintf (stderr, "%s", s1);
  fprintf (stderr, "\n");
}

static void
pfatal_with_name (char *name)
{
  fatal ("%s for %s", strerror (errno), name);
}

static void
pfatal_and_delete (char *name)
{
  char *s = strerror (errno);
  unlink (name);
  fatal ("%s for %s", s, name);
}

/* Return a newly-allocated string whose contents concatenate those of s1, s2, s3.  */

static char *
concat (const char *s1, const char *s2, const char *s3)
{
  size_t len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
  char *result = (char *) xmalloc (len1 + len2 + len3 + 1);

  strcpy (result, s1);
  strcpy (result + len1, s2);
  strcpy (result + len1 + len2, s3);
  *(result + len1 + len2 + len3) = 0;

  return result;
}

/* Like malloc but get fatal error if memory is exhausted.  */

static long *
xmalloc (unsigned int size)
{
  long *result = (long *) malloc (size);
  if (!result)
    fatal ("virtual memory exhausted", 0, 0);
  return result;
}

/* This is the guts of the interface to the Post Office Protocol.  */

#ifdef MAIL_USE_POP

#ifndef WINDOWSNT
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#else
#undef _WINSOCKAPI_
#include <winsock.h>
#endif
#include <pwd.h>
#include <string.h>

#define NOTOK (-1)
#define OK 0
#define DONE 1

char *progname;
FILE *sfi;
FILE *sfo;
char ibuffer[BUFSIZ];
char obuffer[BUFSIZ];
char Errmsg[200];		/* POP errors, at least, can exceed
				   the original length of 80.  */

/*
 * The full valid syntax for a POP mailbox specification for movemail
 * is "po:username:hostname".  The ":hostname" is optional; if it is
 * omitted, the MAILHOST environment variable will be consulted.  Note
 * that by the time popmail() is called the "po:" has been stripped
 * off of the front of the mailbox name.
 *
 * If the mailbox is in the form "po:username:hostname", then it is
 * modified by this function -- the second colon is replaced by a
 * null.
 *
 * Return a value suitable for passing to `exit'.
 */

static int
popmail (char *mailbox, char *outfile, int preserve, char *password, int reverse_order)
{
  int nmsgs, nbytes;
  register int i;
  int mbfi;
  FILE *mbf;
  char *getenv (const char *);
  popserver server;
  int start, end, increment;
  char *user, *hostname;

  user = mailbox;
  if ((hostname = strchr (mailbox, ':')))
    *hostname++ = '\0';

  server = pop_open (hostname, user, password, POP_NO_GETPASS);
  if (! server)
    {
      error ("Error connecting to POP server: %s", pop_error, 0);
      return EXIT_FAILURE;
    }

  if (pop_stat (server, &nmsgs, &nbytes))
    {
      error ("Error getting message count from POP server: %s", pop_error, 0);
      return EXIT_FAILURE;
    }

  if (!nmsgs)
    {
      pop_close (server);
      return EXIT_SUCCESS;
    }

  mbfi = open (outfile, O_WRONLY | O_CREAT | O_EXCL, 0666);
  if (mbfi < 0)
    {
      pop_close (server);
      error ("Error in open: %s, %s", strerror (errno), outfile);
      return EXIT_FAILURE;
    }
  fchown (mbfi, getuid (), -1);

  if ((mbf = fdopen (mbfi, "wb")) == NULL)
    {
      pop_close (server);
      error ("Error in fdopen: %s", strerror (errno), 0);
      close (mbfi);
      unlink (outfile);
      return EXIT_FAILURE;
    }

  if (reverse_order)
    {
      start = nmsgs;
      end = 1;
      increment = -1;
    }
  else
    {
      start = 1;
      end = nmsgs;
      increment = 1;
    }

  for (i = start; i * increment <= end * increment; i += increment)
    {
      mbx_delimit_begin (mbf);
      if (pop_retr (server, i, mbf) != OK)
	{
	  error ("%s", Errmsg, 0);
	  close (mbfi);
	  return EXIT_FAILURE;
	}
      mbx_delimit_end (mbf);
      fflush (mbf);
      if (ferror (mbf))
	{
	  error ("Error in fflush: %s", strerror (errno), 0);
	  pop_close (server);
	  close (mbfi);
	  return EXIT_FAILURE;
	}
    }

  /* On AFS, a call to write only modifies the file in the local
   *     workstation's AFS cache.  The changes are not written to the server
   *      until a call to fsync or close is made.  Users with AFS home
   *      directories have lost mail when over quota because these checks were
   *      not made in previous versions of movemail. */

#ifdef BSD_SYSTEM
  if (fsync (mbfi) < 0)
    {
      error ("Error in fsync: %s", strerror (errno), 0);
      return EXIT_FAILURE;
    }
#endif

  if (close (mbfi) == -1)
    {
      error ("Error in close: %s", strerror (errno), 0);
      return EXIT_FAILURE;
    }

  if (! preserve)
    for (i = 1; i <= nmsgs; i++)
      {
	if (pop_delete (server, i))
	  {
	    error ("Error from POP server: %s", pop_error, 0);
	    pop_close (server);
	    return EXIT_FAILURE;
	  }
      }

  if (pop_quit (server))
    {
      error ("Error from POP server: %s", pop_error, 0);
      return EXIT_FAILURE;
    }

  return EXIT_SUCCESS;
}

static int
pop_retr (popserver server, int msgno, FILE *arg)
{
  char *line;
  int ret;

  if (pop_retrieve_first (server, msgno, &line))
    {
      char *error = concat ("Error from POP server: ", pop_error, "");
      strncpy (Errmsg, error, sizeof (Errmsg));
      Errmsg[sizeof (Errmsg)-1] = '\0';
      free(error);
      return (NOTOK);
    }

  while ((ret = pop_retrieve_next (server, &line)) >= 0)
    {
      if (! line)
	break;

      if (mbx_write (line, ret, arg) != OK)
	{
	  strcpy (Errmsg, strerror (errno));
	  pop_close (server);
	  return (NOTOK);
	}
    }

  if (ret)
    {
      char *error = concat ("Error from POP server: ", pop_error, "");
      strncpy (Errmsg, error, sizeof (Errmsg));
      Errmsg[sizeof (Errmsg)-1] = '\0';
      free(error);
      return (NOTOK);
    }

  return (OK);
}

/* Do this as a macro instead of using strcmp to save on execution time. */
#define IS_FROM_LINE(a) ((a[0] == 'F') \
			 && (a[1] == 'r') \
			 && (a[2] == 'o') \
			 && (a[3] == 'm') \
			 && (a[4] == ' '))

static int
mbx_write (char *line, int len, FILE *mbf)
{
#ifdef MOVEMAIL_QUOTE_POP_FROM_LINES
  if (IS_FROM_LINE (line))
    {
      if (fputc ('>', mbf) == EOF)
	return (NOTOK);
    }
#endif
  if (line[0] == '\037')
    {
      if (fputs ("^_", mbf) == EOF)
	return (NOTOK);
      line++;
      len--;
    }
  if (fwrite (line, 1, len, mbf) != len)
    return (NOTOK);
  if (fputc (0x0a, mbf) == EOF)
    return (NOTOK);
  return (OK);
}

static int
mbx_delimit_begin (FILE *mbf)
{
  time_t now;
  struct tm *ltime;
  char fromline[40] = "From movemail ";

  now = time (NULL);
  ltime = localtime (&now);

  strcat (fromline, asctime (ltime));

  if (fputs (fromline, mbf) == EOF)
    return (NOTOK);
  return (OK);
}

static int
mbx_delimit_end (FILE *mbf)
{
  if (putc ('\n', mbf) == EOF)
    return (NOTOK);
  return (OK);
}

#endif /* MAIL_USE_POP */

#ifndef HAVE_STRERROR
char *
strerror (errnum)
     int errnum;
{
  extern char *sys_errlist[];
  extern int sys_nerr;

  if (errnum >= 0 && errnum < sys_nerr)
    return sys_errlist[errnum];
  return (char *) "Unknown error";
}

#endif /* ! HAVE_STRERROR */


/* movemail.c ends here */