code.delx.au - gnu-emacs/blob - lib-src/movemail.c

   1 /* movemail foo bar -- move file foo to file bar,
   2    locking file foo the way /bin/mail respects.
   3
   4 Copyright (C) 1986, 1992-1994, 1996, 1999, 2001-2015 Free Software
   5 Foundation, Inc.
   6
   7 This file is part of GNU Emacs.
   8
   9 GNU Emacs is free software: you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation, either version 3 of the License, or
  12 (at your option) any later version.
  13
  14 GNU Emacs is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* Important notice: defining MAIL_USE_FLOCK or MAIL_USE_LOCKF *will
  24    cause loss of mail* if you do it on a system that does not normally
  25    use flock/lockf as its way of interlocking access to inbox files.  The
  26    setting of MAIL_USE_FLOCK and MAIL_USE_LOCKF *must agree* with the
  27    system's own conventions.  It is not a choice that is up to you.
  28
  29    So, if your system uses lock files rather than flock, then the only way
  30    you can get proper operation is to enable movemail to write lockfiles there.
  31    This means you must either give that directory access modes
  32    that permit everyone to write lockfiles in it, or you must make movemail
  33    a setuid or setgid program.  */
  34
  35 /*
  36  * Modified January, 1986 by Michael R. Gretzinger (Project Athena)
  37  *
  38  * Added POP (Post Office Protocol) service.  When compiled -DMAIL_USE_POP
  39  * movemail will accept input filename arguments of the form
  40  * "po:username".  This will cause movemail to open a connection to
  41  * a pop server running on $MAILHOST (environment variable).  Movemail
  42  * must be setuid to root in order to work with POP.
  43  *
  44  * New module: popmail.c
  45  * Modified routines:
  46  *      main - added code within #ifdef MAIL_USE_POP; added setuid (getuid ())
  47  *              after POP code.
  48  * New routines in movemail.c:
  49  *      get_errmsg - return pointer to system error message
  50  *
  51  * Modified August, 1993 by Jonathan Kamens (OpenVision Technologies)
  52  *
  53  * Move all of the POP code into a separate file, "pop.c".
  54  * Use strerror instead of get_errmsg.
  55  *
  56  */
  57
  58 #include <config.h>
  59 #include <sys/types.h>
  60 #include <sys/stat.h>
  61 #include <sys/file.h>
  62 #include <stdbool.h>
  63 #include <stdio.h>
  64 #include <errno.h>
  65 #include <time.h>
  66
  67 #include <getopt.h>
  68 #include <unistd.h>
  69 #include <fcntl.h>
  70 #include <signal.h>
  71 #include <string.h>
  72 #include "syswait.h"
  73 #ifdef MAIL_USE_POP
  74 #include "pop.h"
  75 #endif
  76
  77 #ifdef MSDOS
  78 #undef access
  79 #endif /* MSDOS */
  80
  81 #ifdef WINDOWSNT
  82 #include "ntlib.h"
  83 #undef access
  84 #undef unlink
  85 #define fork() 0
  86 #define waitpid(child, var, flags) (*(var) = 0)
  87 /* Unfortunately, Samba doesn't seem to properly lock Unix files even
  88    though the locking call succeeds (and indeed blocks local access from
  89    other NT programs).  If you have direct file access using an NFS
  90    client or something other than Samba, the locking call might work
  91    properly - make sure it does before you enable this!
  92
  93    [18-Feb-97 andrewi] I now believe my comment above to be incorrect,
  94    since it was based on a misunderstanding of how locking calls are
  95    implemented and used on Unix.  */
  96 //#define DISABLE_DIRECT_ACCESS
  97
  98 #include <fcntl.h>
  99 #endif /* WINDOWSNT */
 100
 101 #ifdef WINDOWSNT
 102 #include <sys/locking.h>
 103 #endif
 104
 105 /* If your system uses the `flock' or `lockf' system call for mail locking,
 106    define MAIL_USE_SYSTEM_LOCK.  If your system type should always define
 107    MAIL_USE_LOCKF or MAIL_USE_FLOCK but configure does not do this,
 108    please make a bug report.  */
 109
 110 #ifdef MAIL_USE_LOCKF
 111 #define MAIL_USE_SYSTEM_LOCK
 112 #endif
 113
 114 #ifdef MAIL_USE_FLOCK
 115 #define MAIL_USE_SYSTEM_LOCK
 116 #endif
 117
 118 #ifdef MAIL_USE_MMDF
 119 extern int lk_open (), lk_close ();
 120 #endif
 121
 122 #if !defined (MAIL_USE_SYSTEM_LOCK) && !defined (MAIL_USE_MMDF) && \
 123         (defined (HAVE_LIBMAIL) || defined (HAVE_LIBLOCKFILE)) && \
 124         defined (HAVE_MAILLOCK_H)
 125 #include <maillock.h>
 126 /* We can't use maillock unless we know what directory system mail
 127    files appear in. */
 128 #ifdef MAILDIR
 129 #define MAIL_USE_MAILLOCK
 130 static char *mail_spool_name (char *);
 131 #endif
 132 #endif
 133
 134 static _Noreturn void fatal (const char *s1, const char *s2, const char *s3);
 135 static void error (const char *s1, const char *s2, const char *s3);
 136 static _Noreturn void pfatal_with_name (char *name);
 137 static _Noreturn void pfatal_and_delete (char *name);
 138 #ifdef MAIL_USE_POP
 139 static int popmail (char *, char *, bool, char *, bool);
 140 static bool pop_retr (popserver, int, FILE *);
 141 static bool mbx_write (char *, int, FILE *);
 142 static bool mbx_delimit_begin (FILE *);
 143 static bool mbx_delimit_end (FILE *);
 144 #endif
 145
 146 #if (defined MAIL_USE_MAILLOCK                                          \
 147      || (!defined DISABLE_DIRECT_ACCESS && !defined MAIL_USE_MMDF       \
 148          && !defined MAIL_USE_SYSTEM_LOCK))
 149 /* Like malloc but get fatal error if memory is exhausted.  */
 150
 151 static void *
 152 xmalloc (size_t size)
 153 {
 154   void *result = malloc (size);
 155   if (!result)
 156     fatal ("virtual memory exhausted", 0, 0);
 157   return result;
 158 }
 159 #endif
 160
 161 /* Nonzero means this is name of a lock file to delete on fatal error.  */
 162 static char *delete_lockname;
 163
 164 int
 165 main (int argc, char **argv)
 166 {
 167   char *inname, *outname;
 168   int indesc, outdesc;
 169   ssize_t nread;
 170   int wait_status;
 171   int c;
 172   bool preserve_mail = false;
 173
 174 #ifndef MAIL_USE_SYSTEM_LOCK
 175   struct stat st;
 176   int tem;
 177   char *tempname;
 178   size_t inname_len, inname_dirlen;
 179   int desc;
 180 #endif /* not MAIL_USE_SYSTEM_LOCK */
 181
 182   char *spool_name = 0;
 183
 184 #ifdef MAIL_USE_POP
 185   bool pop_reverse_order = false;
 186 # define ARGSTR "pr"
 187 #else /* ! MAIL_USE_POP */
 188 # define ARGSTR "p"
 189 #endif /* MAIL_USE_POP */
 190
 191   uid_t real_gid = getgid ();
 192   uid_t priv_gid = getegid ();
 193
 194   delete_lockname = 0;
 195
 196   while (0 <= (c = getopt (argc, argv, ARGSTR)))
 197     {
 198       switch (c) {
 199 #ifdef MAIL_USE_POP
 200       case 'r':
 201         pop_reverse_order = true;
 202         break;
 203 #endif
 204       case 'p':
 205         preserve_mail = true;
 206         break;
 207       default:
 208         return EXIT_FAILURE;
 209       }
 210     }
 211
 212   if (
 213 #ifdef MAIL_USE_POP
 214       (argc - optind < 2) || (argc - optind > 3)
 215 #else
 216       (argc - optind != 2)
 217 #endif
 218       )
 219     {
 220 #ifdef MAIL_USE_POP
 221       fprintf (stderr, "Usage: movemail [-p] [-r] inbox destfile%s\n",
 222                " [POP-password]");
 223 #else
 224       fprintf (stderr, "Usage: movemail [-p] inbox destfile%s\n", "");
 225 #endif
 226       return EXIT_FAILURE;
 227     }
 228
 229   inname = argv[optind];
 230   outname = argv[optind+1];
 231
 232 #ifdef MAIL_USE_MMDF
 233   mmdf_init (argv[0]);
 234 #endif
 235
 236   if (*outname == 0)
 237     fatal ("Destination file name is empty", 0, 0);
 238
 239 #ifdef MAIL_USE_POP
 240   if (!strncmp (inname, "po:", 3))
 241     {
 242       int status;
 243
 244       status = popmail (inname + 3, outname, preserve_mail,
 245                         (argc - optind == 3) ? argv[optind+2] : NULL,
 246                         pop_reverse_order);
 247       return status;
 248     }
 249
 250   if (setuid (getuid ()) < 0)
 251     fatal ("Failed to drop privileges", 0, 0);
 252
 253 #endif /* MAIL_USE_POP */
 254
 255 #ifndef DISABLE_DIRECT_ACCESS
 256
 257   char *lockname = 0;
 258
 259 #ifndef MAIL_USE_MMDF
 260 #ifndef MAIL_USE_SYSTEM_LOCK
 261 #ifdef MAIL_USE_MAILLOCK
 262   spool_name = mail_spool_name (inname);
 263 #endif
 264   if (! spool_name)
 265     {
 266       /* Use a lock file named after our first argument with .lock appended:
 267          If it exists, the mail file is locked.  */
 268       /* Note: this locking mechanism is *required* by the mailer
 269          (on systems which use it) to prevent loss of mail.
 270
 271          On systems that use a lock file, extracting the mail without locking
 272          WILL occasionally cause loss of mail due to timing errors!
 273
 274          So, if creation of the lock file fails due to access
 275          permission on the mail spool directory, you simply MUST
 276          change the permission and/or make movemail a setgid program
 277          so it can create lock files properly.
 278
 279          You might also wish to verify that your system is one which
 280          uses lock files for this purpose.  Some systems use other methods.  */
 281
 282       inname_len = strlen (inname);
 283       lockname = xmalloc (inname_len + sizeof ".lock");
 284       strcpy (lockname, inname);
 285       strcpy (lockname + inname_len, ".lock");
 286       for (inname_dirlen = inname_len;
 287            inname_dirlen && !IS_DIRECTORY_SEP (inname[inname_dirlen - 1]);
 288            inname_dirlen--)
 289         continue;
 290       tempname = xmalloc (inname_dirlen + sizeof "EXXXXXX");
 291
 292       while (true)
 293         {
 294           /* Create the lock file, but not under the lock file name.  */
 295           /* Give up if cannot do that.  */
 296
 297           memcpy (tempname, inname, inname_dirlen);
 298           strcpy (tempname + inname_dirlen, "EXXXXXX");
 299           desc = mkostemp (tempname, O_BINARY);
 300           if (desc < 0)
 301             {
 302               int mkostemp_errno = errno;
 303               error ("error while creating what would become the lock file",
 304                      0, 0);
 305               errno = mkostemp_errno;
 306               pfatal_with_name (tempname);
 307             }
 308           close (desc);
 309
 310           tem = link (tempname, lockname);
 311
 312           if (tem < 0 && errno != EEXIST)
 313             pfatal_with_name (lockname);
 314
 315           unlink (tempname);
 316           if (tem >= 0)
 317             break;
 318           sleep (1);
 319
 320           /* If lock file is five minutes old, unlock it.
 321              Five minutes should be good enough to cope with crashes
 322              and wedgitude, and long enough to avoid being fooled
 323              by time differences between machines.  */
 324           if (stat (lockname, &st) >= 0)
 325             {
 326               time_t now = time (0);
 327               if (st.st_ctime < now - 300)
 328                 {
 329                   unlink (lockname);
 330                   lockname = 0;
 331                 }
 332             }
 333         }
 334
 335       delete_lockname = lockname;
 336     }
 337 #endif /* not MAIL_USE_SYSTEM_LOCK */
 338 #endif /* not MAIL_USE_MMDF */
 339
 340 #ifdef SIGCHLD
 341   signal (SIGCHLD, SIG_DFL);
 342 #endif
 343
 344   pid_t child = fork ();
 345   if (child < 0)
 346     fatal ("Error in fork; %s", strerror (errno), 0);
 347
 348   if (child == 0)
 349     {
 350       int lockcount = 0;
 351       int status = 0;
 352 #if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
 353       time_t touched_lock IF_LINT (= 0);
 354 #endif
 355
 356       if (setuid (getuid ()) < 0 || setregid (-1, real_gid) < 0)
 357         fatal ("Failed to drop privileges", 0, 0);
 358
 359 #ifndef MAIL_USE_MMDF
 360 #ifdef MAIL_USE_SYSTEM_LOCK
 361       indesc = open (inname, O_RDWR | O_BINARY);
 362 #else  /* if not MAIL_USE_SYSTEM_LOCK */
 363       indesc = open (inname, O_RDONLY | O_BINARY);
 364 #endif /* not MAIL_USE_SYSTEM_LOCK */
 365 #else  /* MAIL_USE_MMDF */
 366       indesc = lk_open (inname, O_RDONLY | O_BINARY, 0, 0, 10);
 367 #endif /* MAIL_USE_MMDF */
 368
 369       if (indesc < 0)
 370         pfatal_with_name (inname);
 371
 372       /* Make sure the user can read the output file.  */
 373       umask (umask (0) & 0377);
 374
 375       outdesc = open (outname, O_WRONLY | O_BINARY | O_CREAT | O_EXCL, 0666);
 376       if (outdesc < 0)
 377         pfatal_with_name (outname);
 378
 379       if (setregid (-1, priv_gid) < 0)
 380         fatal ("Failed to regain privileges", 0, 0);
 381
 382       /* This label exists so we can retry locking
 383          after a delay, if it got EAGAIN or EBUSY.  */
 384     retry_lock:
 385
 386       /* Try to lock it.  */
 387 #ifdef MAIL_USE_MAILLOCK
 388       if (spool_name)
 389         {
 390           /* The "-" is to make it a negative number if maillock returns
 391              non-zero. */
 392           status = - maillock (spool_name, 1);
 393 #ifdef HAVE_TOUCHLOCK
 394           touched_lock = time (0);
 395 #endif
 396           lockcount = 5;
 397         }
 398       else
 399 #endif /* MAIL_USE_MAILLOCK */
 400         {
 401 #ifdef MAIL_USE_SYSTEM_LOCK
 402 #ifdef MAIL_USE_LOCKF
 403           status = lockf (indesc, F_LOCK, 0);
 404 #else /* not MAIL_USE_LOCKF */
 405 #ifdef WINDOWSNT
 406           status = locking (indesc, LK_RLCK, -1L);
 407 #else
 408           status = flock (indesc, LOCK_EX);
 409 #endif
 410 #endif /* not MAIL_USE_LOCKF */
 411 #endif /* MAIL_USE_SYSTEM_LOCK */
 412         }
 413
 414       /* If it fails, retry up to 5 times
 415          for certain failure codes.  */
 416       if (status < 0)
 417         {
 418           if (++lockcount <= 5 && (errno == EAGAIN || errno == EBUSY))
 419             {
 420               sleep (1);
 421               goto retry_lock;
 422             }
 423
 424           pfatal_with_name (inname);
 425         }
 426
 427       {
 428         char buf[1024];
 429
 430         while (true)
 431           {
 432             nread = read (indesc, buf, sizeof buf);
 433             if (nread < 0)
 434               pfatal_with_name (inname);
 435             if (nread != write (outdesc, buf, nread))
 436               {
 437                 int saved_errno = errno;
 438                 unlink (outname);
 439                 errno = saved_errno;
 440                 pfatal_with_name (outname);
 441               }
 442             if (nread < sizeof buf)
 443               break;
 444 #if defined (MAIL_USE_MAILLOCK) && defined (HAVE_TOUCHLOCK)
 445             if (spool_name)
 446               {
 447                 time_t now = time (0);
 448                 if (now - touched_lock > 60)
 449                   {
 450                     touchlock ();
 451                     touched_lock = now;
 452                   }
 453               }
 454 #endif /* MAIL_USE_MAILLOCK */
 455           }
 456       }
 457
 458       if (fsync (outdesc) != 0 && errno != EINVAL)
 459         pfatal_and_delete (outname);
 460
 461       /* Prevent symlink attacks truncating other users' mailboxes */
 462       if (setregid (-1, real_gid) < 0)
 463         fatal ("Failed to drop privileges", 0, 0);
 464
 465       /* Check to make sure no errors before we zap the inbox.  */
 466       if (close (outdesc) != 0)
 467         pfatal_and_delete (outname);
 468
 469 #ifdef MAIL_USE_SYSTEM_LOCK
 470       if (! preserve_mail)
 471         {
 472           if (ftruncate (indesc, 0) != 0)
 473             pfatal_with_name (inname);
 474         }
 475 #endif /* MAIL_USE_SYSTEM_LOCK */
 476
 477 #ifdef MAIL_USE_MMDF
 478       lk_close (indesc, 0, 0, 0);
 479 #else
 480       close (indesc);
 481 #endif
 482
 483 #ifndef MAIL_USE_SYSTEM_LOCK
 484       if (! preserve_mail)
 485         {
 486           /* Delete the input file; if we can't, at least get rid of its
 487              contents.  */
 488 #ifdef MAIL_UNLINK_SPOOL
 489           /* This is generally bad to do, because it destroys the permissions
 490              that were set on the file.  Better to just empty the file.  */
 491           if (unlink (inname) < 0 && errno != ENOENT)
 492 #endif /* MAIL_UNLINK_SPOOL */
 493             creat (inname, 0600);
 494         }
 495 #endif /* not MAIL_USE_SYSTEM_LOCK */
 496
 497       /* End of mailbox truncation */
 498       if (setregid (-1, priv_gid) < 0)
 499         fatal ("Failed to regain privileges", 0, 0);
 500
 501 #ifdef MAIL_USE_MAILLOCK
 502       /* This has to occur in the child, i.e., in the process that
 503          acquired the lock! */
 504       if (spool_name)
 505         mailunlock ();
 506 #endif
 507       return EXIT_SUCCESS;
 508     }
 509
 510   if (waitpid (child, &wait_status, 0) < 0)
 511     fatal ("Error in waitpid; %s", strerror (errno), 0);
 512   if (!WIFEXITED (wait_status))
 513     return EXIT_FAILURE;
 514   else if (WEXITSTATUS (wait_status) != 0)
 515     return WEXITSTATUS (wait_status);
 516
 517   if (lockname)
 518     unlink (lockname);
 519
 520 #endif /* ! DISABLE_DIRECT_ACCESS */
 521
 522   return EXIT_SUCCESS;
 523 }
 524
 525 #ifdef MAIL_USE_MAILLOCK
 526 /* This function uses stat to confirm that the mail directory is
 527    identical to the directory of the input file, rather than just
 528    string-comparing the two paths, because one or both of them might
 529    be symbolic links pointing to some other directory. */
 530 static char *
 531 mail_spool_name (char *inname)
 532 {
 533   struct stat stat1, stat2;
 534   char *indir, *fname;
 535   int status;
 536
 537   if (! (fname = strrchr (inname, '/')))
 538     return NULL;
 539
 540   fname++;
 541
 542   if (stat (MAILDIR, &stat1) < 0)
 543     return NULL;
 544
 545   indir = xmalloc (fname - inname + 1);
 546   memcpy (indir, inname, fname - inname);
 547   indir[fname-inname] = '\0';
 548
 549
 550   status = stat (indir, &stat2);
 551
 552   free (indir);
 553
 554   if (status < 0)
 555     return NULL;
 556
 557   if (stat1.st_dev == stat2.st_dev
 558       && stat1.st_ino == stat2.st_ino)
 559     return fname;
 560
 561   return NULL;
 562 }
 563 #endif /* MAIL_USE_MAILLOCK */
 564 \f
 565 /* Print error message and exit.  */
 566
 567 static void
 568 fatal (const char *s1, const char *s2, const char *s3)
 569 {
 570   if (delete_lockname)
 571     unlink (delete_lockname);
 572   error (s1, s2, s3);
 573   exit (EXIT_FAILURE);
 574 }
 575
 576 /* Print error message.  `s1' is printf control string, `s2' and `s3'
 577    are args for it or null. */
 578
 579 static void
 580 error (const char *s1, const char *s2, const char *s3)
 581 {
 582   fprintf (stderr, "movemail: ");
 583   if (s3)
 584     fprintf (stderr, s1, s2, s3);
 585   else if (s2)
 586     fprintf (stderr, s1, s2);
 587   else
 588     fprintf (stderr, "%s", s1);
 589   fprintf (stderr, "\n");
 590 }
 591
 592 static void
 593 pfatal_with_name (char *name)
 594 {
 595   fatal ("%s for %s", strerror (errno), name);
 596 }
 597
 598 static void
 599 pfatal_and_delete (char *name)
 600 {
 601   char *s = strerror (errno);
 602   unlink (name);
 603   fatal ("%s for %s", s, name);
 604 }
 605 \f
 606 /* This is the guts of the interface to the Post Office Protocol.  */
 607
 608 #ifdef MAIL_USE_POP
 609
 610 #ifndef WINDOWSNT
 611 #include <sys/socket.h>
 612 #include <netinet/in.h>
 613 #include <netdb.h>
 614 #else
 615 #undef _WINSOCKAPI_
 616 #include <winsock.h>
 617 #endif
 618 #include <pwd.h>
 619 #include <string.h>
 620
 621 /*
 622  * The full valid syntax for a POP mailbox specification for movemail
 623  * is "po:username:hostname".  The ":hostname" is optional; if it is
 624  * omitted, the MAILHOST environment variable will be consulted.  Note
 625  * that by the time popmail() is called the "po:" has been stripped
 626  * off of the front of the mailbox name.
 627  *
 628  * If the mailbox is in the form "po:username:hostname", then it is
 629  * modified by this function -- the second colon is replaced by a
 630  * null.
 631  *
 632  * Return a value suitable for passing to `exit'.
 633  */
 634
 635 static int
 636 popmail (char *mailbox, char *outfile, bool preserve, char *password,
 637          bool reverse_order)
 638 {
 639   int nmsgs, nbytes;
 640   int i;
 641   int mbfi;
 642   FILE *mbf;
 643   popserver server;
 644   int start, end, increment;
 645   char *user, *hostname;
 646
 647   user = mailbox;
 648   if ((hostname = strchr (mailbox, ':')))
 649     *hostname++ = '\0';
 650
 651   server = pop_open (hostname, user, password, POP_NO_GETPASS);
 652   if (! server)
 653     {
 654       error ("Error connecting to POP server: %s", pop_error, 0);
 655       return EXIT_FAILURE;
 656     }
 657
 658   if (pop_stat (server, &nmsgs, &nbytes))
 659     {
 660       error ("Error getting message count from POP server: %s", pop_error, 0);
 661       return EXIT_FAILURE;
 662     }
 663
 664   if (!nmsgs)
 665     {
 666       pop_close (server);
 667       return EXIT_SUCCESS;
 668     }
 669
 670   mbfi = open (outfile, O_WRONLY | O_BINARY | O_CREAT | O_EXCL, 0666);
 671   if (mbfi < 0)
 672     {
 673       pop_close (server);
 674       error ("Error in open: %s, %s", strerror (errno), outfile);
 675       return EXIT_FAILURE;
 676     }
 677
 678   if (fchown (mbfi, getuid (), -1) != 0)
 679     {
 680       int fchown_errno = errno;
 681       struct stat st;
 682       if (fstat (mbfi, &st) != 0 || st.st_uid != getuid ())
 683         {
 684           pop_close (server);
 685           error ("Error in fchown: %s, %s", strerror (fchown_errno), outfile);
 686           return EXIT_FAILURE;
 687         }
 688     }
 689
 690   mbf = fdopen (mbfi, "wb");
 691   if (!mbf)
 692     {
 693       pop_close (server);
 694       error ("Error in fdopen: %s", strerror (errno), 0);
 695       close (mbfi);
 696       unlink (outfile);
 697       return EXIT_FAILURE;
 698     }
 699
 700   if (reverse_order)
 701     {
 702       start = nmsgs;
 703       end = 1;
 704       increment = -1;
 705     }
 706   else
 707     {
 708       start = 1;
 709       end = nmsgs;
 710       increment = 1;
 711     }
 712
 713   for (i = start; i * increment <= end * increment; i += increment)
 714     if (! (mbx_delimit_begin (mbf)
 715            && pop_retr (server, i, mbf)
 716            && mbx_delimit_end (mbf)
 717            && fflush (mbf) == 0))
 718       {
 719         if (errno)
 720           error ("Error in POP retrieving: %s", strerror (errno), 0);
 721         pop_close (server);
 722         fclose (mbf);
 723         return EXIT_FAILURE;
 724       }
 725
 726   if (fsync (mbfi) != 0 && errno != EINVAL)
 727     {
 728       error ("Error in fsync: %s", strerror (errno), 0);
 729       fclose (mbf);
 730       return EXIT_FAILURE;
 731     }
 732
 733   if (fclose (mbf) != 0)
 734     {
 735       error ("Error in fclose: %s", strerror (errno), 0);
 736       return EXIT_FAILURE;
 737     }
 738
 739   if (! preserve)
 740     for (i = 1; i <= nmsgs; i++)
 741       {
 742         if (pop_delete (server, i))
 743           {
 744             error ("Error from POP server: %s", pop_error, 0);
 745             pop_close (server);
 746             return EXIT_FAILURE;
 747           }
 748       }
 749
 750   if (pop_quit (server))
 751     {
 752       error ("Error from POP server: %s", pop_error, 0);
 753       return EXIT_FAILURE;
 754     }
 755
 756   return EXIT_SUCCESS;
 757 }
 758
 759 static bool
 760 pop_retr (popserver server, int msgno, FILE *arg)
 761 {
 762   char *line;
 763   int ret;
 764
 765   if (pop_retrieve_first (server, msgno, &line))
 766     {
 767       error ("Error from POP server: %s", pop_error, 0);
 768       errno = 0;
 769       return false;
 770     }
 771
 772   while ((ret = pop_retrieve_next (server, &line)) >= 0)
 773     {
 774       if (! line)
 775         break;
 776
 777       if (! mbx_write (line, ret, arg))
 778         {
 779           int write_errno = errno;
 780           pop_close (server);
 781           errno = write_errno;
 782           return false;
 783         }
 784     }
 785
 786   if (ret)
 787     {
 788       error ("Error from POP server: %s", pop_error, 0);
 789       errno = 0;
 790       return false;
 791     }
 792
 793   return true;
 794 }
 795
 796 static bool
 797 mbx_write (char *line, int len, FILE *mbf)
 798 {
 799 #ifdef MOVEMAIL_QUOTE_POP_FROM_LINES
 800   /* Do this as a macro instead of using strcmp to save on execution time. */
 801   # define IS_FROM_LINE(a) ((a[0] == 'F')       \
 802                             && (a[1] == 'r')    \
 803                             && (a[2] == 'o')    \
 804                             && (a[3] == 'm')    \
 805                             && (a[4] == ' '))
 806   if (IS_FROM_LINE (line))
 807     {
 808       if (fputc ('>', mbf) < 0)
 809         return false;
 810     }
 811 #endif
 812   if (line[0] == '\037')
 813     {
 814       if (fputs ("^_", mbf) < 0)
 815         return false;
 816       line++;
 817       len--;
 818     }
 819   return fwrite (line, 1, len, mbf) == len && 0 <= fputc ('\n', mbf);
 820 }
 821
 822 static bool
 823 mbx_delimit_begin (FILE *mbf)
 824 {
 825   time_t now = time (NULL);
 826   struct tm *ltime = localtime (&now);
 827   if (!ltime)
 828     return false;
 829
 830   char fromline[100];
 831   if (! strftime (fromline, sizeof fromline,
 832                   "From movemail %a %b %e %T %Y\n", ltime))
 833     {
 834       errno = EOVERFLOW;
 835       return false;
 836     }
 837   return 0 <= fputs (fromline, mbf);
 838 }
 839
 840 static bool
 841 mbx_delimit_end (FILE *mbf)
 842 {
 843   return 0 <= putc ('\n', mbf);
 844 }
 845
 846 #endif /* MAIL_USE_POP */