lib-src/movemail.c

   1 /* movemail foo bar -- move file foo to file bar,
   2    locking file foo the way /bin/mail respects.
   3    Copyright (C) 1986, 1992, 1993, 1994 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /* Important notice: defining MAIL_USE_FLOCK or MAIL_USE_LOCKF *will
  22    cause loss of mail* if you do it on a system that does not normally
  23    use flock as its way of interlocking access to inbox files.  The
  24    setting of MAIL_USE_FLOCK and MAIL_USE_LOCKF *must agree* with the
  25    system's own conventions.  It is not a choice that is up to you.
  26
  27    So, if your system uses lock files rather than flock, then the only way
  28    you can get proper operation is to enable movemail to write lockfiles there.
  29    This means you must either give that directory access modes
  30    that permit everyone to write lockfiles in it, or you must make movemail
  31    a setuid or setgid program.  */
  32
  33 /*
  34  * Modified January, 1986 by Michael R. Gretzinger (Project Athena)
  35  *
  36  * Added POP (Post Office Protocol) service.  When compiled -DPOP
  37  * movemail will accept input filename arguments of the form
  38  * "po:username".  This will cause movemail to open a connection to
  39  * a pop server running on $MAILHOST (environment variable).  Movemail
  40  * must be setuid to root in order to work with POP.
  41  *
  42  * New module: popmail.c
  43  * Modified routines:
  44  *      main - added code within #ifdef MAIL_USE_POP; added setuid (getuid ())
  45  *              after POP code.
  46  * New routines in movemail.c:
  47  *      get_errmsg - return pointer to system error message
  48  *
  49  * Modified August, 1993 by Jonathan Kamens (OpenVision Technologies)
  50  *
  51  * Move all of the POP code into a separate file, "pop.c".
  52  * Use strerror instead of get_errmsg.
  53  *
  54  */
  55
  56 #define NO_SHORTNAMES   /* Tell config not to load remap.h */
  57 #include <../src/config.h>
  58 #include <sys/types.h>
  59 #include <sys/stat.h>
  60 #include <sys/file.h>
  61 #include <stdio.h>
  62 #include <errno.h>
  63 #include <../src/syswait.h>
  64 #ifdef MAIL_USE_POP
  65 #include "pop.h"
  66 #endif
  67
  68 #ifdef MSDOS
  69 #undef access
  70 #endif /* MSDOS */
  71
  72 #ifdef USG
  73 #include <fcntl.h>
  74 #include <unistd.h>
  75 #ifndef F_OK
  76 #define F_OK 0
  77 #define X_OK 1
  78 #define W_OK 2
  79 #define R_OK 4
  80 #endif
  81 #endif /* USG */
  82
  83 #ifdef HAVE_UNISTD_H
  84 #include <unistd.h>
  85 #endif
  86
  87 #ifdef XENIX
  88 #include <sys/locking.h>
  89 #endif
  90
  91 #ifdef MAIL_USE_LOCKF
  92 #define MAIL_USE_SYSTEM_LOCK
  93 #endif
  94
  95 #ifdef MAIL_USE_FLOCK
  96 #define MAIL_USE_SYSTEM_LOCK
  97 #endif
  98
  99 #ifdef MAIL_USE_MMDF
 100 extern int lk_open (), lk_close ();
 101 #endif
 102
 103 /* Cancel substitutions made by config.h for Emacs.  */
 104 #undef open
 105 #undef read
 106 #undef write
 107 #undef close
 108
 109 #ifndef errno
 110 extern int errno;
 111 #endif
 112 char *strerror ();
 113
 114 void fatal ();
 115 void error ();
 116 void pfatal_with_name ();
 117 void pfatal_and_delete ();
 118 char *concat ();
 119 long *xmalloc ();
 120 int popmail ();
 121 int pop_retr ();
 122 int mbx_write ();
 123 int mbx_delimit_begin ();
 124 int mbx_delimit_end ();
 125
 126 /* Nonzero means this is name of a lock file to delete on fatal error.  */
 127 char *delete_lockname;
 128
 129 int
 130 main (argc, argv)
 131      int argc;
 132      char **argv;
 133 {
 134   char *inname, *outname;
 135   int indesc, outdesc;
 136   int nread;
 137   WAITTYPE status;
 138
 139 #ifndef MAIL_USE_SYSTEM_LOCK
 140   struct stat st;
 141   long now;
 142   int tem;
 143   char *lockname, *p;
 144   char *tempname;
 145   int desc;
 146 #endif /* not MAIL_USE_SYSTEM_LOCK */
 147
 148   delete_lockname = 0;
 149
 150   if (argc < 3)
 151     {
 152       fprintf (stderr, "Usage: movemail inbox destfile\n");
 153       exit(1);
 154     }
 155
 156   inname = argv[1];
 157   outname = argv[2];
 158
 159 #ifdef MAIL_USE_MMDF
 160   mmdf_init (argv[0]);
 161 #endif
 162
 163   if (*outname == 0)
 164     fatal ("Destination file name is empty", 0);
 165
 166   /* Check access to output file.  */
 167   if (access (outname, F_OK) == 0 && access (outname, W_OK) != 0)
 168     pfatal_with_name (outname);
 169
 170   /* Also check that outname's directory is writable to the real uid.  */
 171   {
 172     char *buf = (char *) xmalloc (strlen (outname) + 1);
 173     char *p;
 174     strcpy (buf, outname);
 175     p = buf + strlen (buf);
 176     while (p > buf && p[-1] != '/')
 177       *--p = 0;
 178     if (p == buf)
 179       *p++ = '.';
 180     if (access (buf, W_OK) != 0)
 181       pfatal_with_name (buf);
 182     free (buf);
 183   }
 184
 185 #ifdef MAIL_USE_POP
 186   if (!strncmp (inname, "po:", 3))
 187     {
 188       int status;
 189
 190       status = popmail (inname + 3, outname);
 191       exit (status);
 192     }
 193
 194   setuid (getuid ());
 195 #endif /* MAIL_USE_POP */
 196
 197   /* Check access to input file.  */
 198   if (access (inname, R_OK | W_OK) != 0)
 199     pfatal_with_name (inname);
 200
 201 #ifndef MAIL_USE_MMDF
 202 #ifndef MAIL_USE_SYSTEM_LOCK
 203   /* Use a lock file named after our first argument with .lock appended:
 204      If it exists, the mail file is locked.  */
 205   /* Note: this locking mechanism is *required* by the mailer
 206      (on systems which use it) to prevent loss of mail.
 207
 208      On systems that use a lock file, extracting the mail without locking
 209      WILL occasionally cause loss of mail due to timing errors!
 210
 211      So, if creation of the lock file fails
 212      due to access permission on the mail spool directory,
 213      you simply MUST change the permission
 214      and/or make movemail a setgid program
 215      so it can create lock files properly.
 216
 217      You might also wish to verify that your system is one
 218      which uses lock files for this purpose.  Some systems use other methods.
 219
 220      If your system uses the `flock' system call for mail locking,
 221      define MAIL_USE_SYSTEM_LOCK in config.h or the s-*.h file
 222      and recompile movemail.  If the s- file for your system
 223      should define MAIL_USE_SYSTEM_LOCK but does not, send a bug report
 224      to bug-gnu-emacs@prep.ai.mit.edu so we can fix it.  */
 225
 226   lockname = concat (inname, ".lock", "");
 227   tempname = (char *) xmalloc (strlen (inname) + strlen ("EXXXXXX") + 1);
 228   strcpy (tempname, inname);
 229   p = tempname + strlen (tempname);
 230   while (p != tempname && p[-1] != '/')
 231     p--;
 232   *p = 0;
 233   strcpy (p, "EXXXXXX");
 234   mktemp (tempname);
 235   unlink (tempname);
 236
 237   while (1)
 238     {
 239       /* Create the lock file, but not under the lock file name.  */
 240       /* Give up if cannot do that.  */
 241       desc = open (tempname, O_WRONLY | O_CREAT | O_EXCL, 0666);
 242       if (desc < 0)
 243         {
 244           char *message = (char *) xmalloc (strlen (tempname) + 50);
 245           sprintf (message, "%s--see source file lib-src/movemail.c",
 246                    tempname);
 247           pfatal_with_name (message);
 248         }
 249       close (desc);
 250
 251       tem = link (tempname, lockname);
 252       unlink (tempname);
 253       if (tem >= 0)
 254         break;
 255       sleep (1);
 256
 257       /* If lock file is five minutes old, unlock it.
 258          Five minutes should be good enough to cope with crashes
 259          and wedgitude, and long enough to avoid being fooled
 260          by time differences between machines.  */
 261       if (stat (lockname, &st) >= 0)
 262         {
 263           now = time (0);
 264           if (st.st_ctime < now - 300)
 265             unlink (lockname);
 266         }
 267     }
 268
 269   delete_lockname = lockname;
 270 #endif /* not MAIL_USE_SYSTEM_LOCK */
 271 #endif /* not MAIL_USE_MMDF */
 272
 273   if (fork () == 0)
 274     {
 275       setuid (getuid ());
 276
 277 #ifndef MAIL_USE_MMDF
 278 #ifdef MAIL_USE_SYSTEM_LOCK
 279       indesc = open (inname, O_RDWR);
 280 #else  /* if not MAIL_USE_SYSTEM_LOCK */
 281       indesc = open (inname, O_RDONLY);
 282 #endif /* not MAIL_USE_SYSTEM_LOCK */
 283 #else  /* MAIL_USE_MMDF */
 284       indesc = lk_open (inname, O_RDONLY, 0, 0, 10);
 285 #endif /* MAIL_USE_MMDF */
 286
 287       if (indesc < 0)
 288         pfatal_with_name (inname);
 289
 290 #if defined (BSD) || defined (XENIX)
 291       /* In case movemail is setuid to root, make sure the user can
 292          read the output file.  */
 293       /* This is desirable for all systems
 294          but I don't want to assume all have the umask system call */
 295       umask (umask (0) & 0333);
 296 #endif /* BSD or Xenix */
 297       outdesc = open (outname, O_WRONLY | O_CREAT | O_EXCL, 0666);
 298       if (outdesc < 0)
 299         pfatal_with_name (outname);
 300 #ifdef MAIL_USE_SYSTEM_LOCK
 301 #ifdef MAIL_USE_LOCKF
 302       if (lockf (indesc, F_LOCK, 0) < 0) pfatal_with_name (inname);
 303 #else /* not MAIL_USE_LOCKF */
 304 #ifdef XENIX
 305       if (locking (indesc, LK_RLCK, 0L) < 0) pfatal_with_name (inname);
 306 #else
 307       if (flock (indesc, LOCK_EX) < 0) pfatal_with_name (inname);
 308 #endif
 309 #endif /* not MAIL_USE_LOCKF */
 310 #endif /* MAIL_USE_SYSTEM_LOCK */
 311
 312       {
 313         char buf[1024];
 314
 315         while (1)
 316           {
 317             nread = read (indesc, buf, sizeof buf);
 318             if (nread != write (outdesc, buf, nread))
 319               {
 320                 int saved_errno = errno;
 321                 unlink (outname);
 322                 errno = saved_errno;
 323                 pfatal_with_name (outname);
 324               }
 325             if (nread < sizeof buf)
 326               break;
 327           }
 328       }
 329
 330 #ifdef BSD
 331       if (fsync (outdesc) < 0)
 332         pfatal_and_delete (outname);
 333 #endif
 334
 335       /* Check to make sure no errors before we zap the inbox.  */
 336       if (close (outdesc) != 0)
 337         pfatal_and_delete (outname);
 338
 339 #ifdef MAIL_USE_SYSTEM_LOCK
 340 #if defined (STRIDE) || defined (XENIX)
 341       /* Stride, xenix have file locking, but no ftruncate.  This mess will do. */
 342       close (open (inname, O_CREAT | O_TRUNC | O_RDWR, 0666));
 343 #else
 344       ftruncate (indesc, 0L);
 345 #endif /* STRIDE or XENIX */
 346 #endif /* MAIL_USE_SYSTEM_LOCK */
 347
 348 #ifdef MAIL_USE_MMDF
 349       lk_close (indesc, 0, 0, 0);
 350 #else
 351       close (indesc);
 352 #endif
 353
 354 #ifndef MAIL_USE_SYSTEM_LOCK
 355       /* Delete the input file; if we can't, at least get rid of its
 356          contents.  */
 357 #ifdef MAIL_UNLINK_SPOOL
 358       /* This is generally bad to do, because it destroys the permissions
 359          that were set on the file.  Better to just empty the file.  */
 360       if (unlink (inname) < 0 && errno != ENOENT)
 361 #endif /* MAIL_UNLINK_SPOOL */
 362         creat (inname, 0600);
 363 #endif /* not MAIL_USE_SYSTEM_LOCK */
 364
 365       exit (0);
 366     }
 367
 368   wait (&status);
 369   if (!WIFEXITED (status))
 370     exit (1);
 371   else if (WRETCODE (status) != 0)
 372     exit (WRETCODE (status));
 373
 374 #if !defined (MAIL_USE_MMDF) && !defined (MAIL_USE_SYSTEM_LOCK)
 375   unlink (lockname);
 376 #endif /* not MAIL_USE_MMDF and not MAIL_USE_SYSTEM_LOCK */
 377   return 0;
 378 }
 379 \f
 380 /* Print error message and exit.  */
 381
 382 void
 383 fatal (s1, s2)
 384      char *s1, *s2;
 385 {
 386   if (delete_lockname)
 387     unlink (delete_lockname);
 388   error (s1, s2);
 389   exit (1);
 390 }
 391
 392 /* Print error message.  `s1' is printf control string, `s2' is arg for it. */
 393
 394 void
 395 error (s1, s2, s3)
 396      char *s1, *s2, *s3;
 397 {
 398   fprintf (stderr, "movemail: ");
 399   fprintf (stderr, s1, s2, s3);
 400   fprintf (stderr, "\n");
 401 }
 402
 403 void
 404 pfatal_with_name (name)
 405      char *name;
 406 {
 407   char *s = concat ("", strerror (errno), " for %s");
 408   fatal (s, name);
 409 }
 410
 411 void
 412 pfatal_and_delete (name)
 413      char *name;
 414 {
 415   char *s = concat ("", strerror (errno), " for %s");
 416   unlink (name);
 417   fatal (s, name);
 418 }
 419
 420 /* Return a newly-allocated string whose contents concatenate those of s1, s2, s3.  */
 421
 422 char *
 423 concat (s1, s2, s3)
 424      char *s1, *s2, *s3;
 425 {
 426   int len1 = strlen (s1), len2 = strlen (s2), len3 = strlen (s3);
 427   char *result = (char *) xmalloc (len1 + len2 + len3 + 1);
 428
 429   strcpy (result, s1);
 430   strcpy (result + len1, s2);
 431   strcpy (result + len1 + len2, s3);
 432   *(result + len1 + len2 + len3) = 0;
 433
 434   return result;
 435 }
 436
 437 /* Like malloc but get fatal error if memory is exhausted.  */
 438
 439 long *
 440 xmalloc (size)
 441      unsigned size;
 442 {
 443   long *result = (long *) malloc (size);
 444   if (!result)
 445     fatal ("virtual memory exhausted", 0);
 446   return result;
 447 }
 448 \f
 449 /* This is the guts of the interface to the Post Office Protocol.  */
 450
 451 #ifdef MAIL_USE_POP
 452
 453 #include <sys/socket.h>
 454 #include <netinet/in.h>
 455 #include <netdb.h>
 456 #include <stdio.h>
 457 #include <pwd.h>
 458
 459 #ifdef USG
 460 #include <fcntl.h>
 461 /* Cancel substitutions made by config.h for Emacs.  */
 462 #undef open
 463 #undef read
 464 #undef write
 465 #undef close
 466 #endif /* USG */
 467
 468 #define NOTOK (-1)
 469 #define OK 0
 470 #define DONE 1
 471
 472 char *progname;
 473 FILE *sfi;
 474 FILE *sfo;
 475 char ibuffer[BUFSIZ];
 476 char obuffer[BUFSIZ];
 477 char Errmsg[80];
 478
 479 popmail (user, outfile)
 480      char *user;
 481      char *outfile;
 482 {
 483   int nmsgs, nbytes;
 484   register int i;
 485   int mbfi;
 486   FILE *mbf;
 487   char *getenv ();
 488   int mbx_write ();
 489   popserver server;
 490   extern char *strerror ();
 491
 492   server = pop_open (0, user, 0, POP_NO_GETPASS);
 493   if (! server)
 494     {
 495       error (pop_error);
 496       return (1);
 497     }
 498
 499   if (pop_stat (server, &nmsgs, &nbytes))
 500     {
 501       error (pop_error);
 502       return (1);
 503     }
 504
 505   if (!nmsgs)
 506     {
 507       pop_close (server);
 508       return (0);
 509     }
 510
 511   mbfi = open (outfile, O_WRONLY | O_CREAT | O_EXCL, 0666);
 512   if (mbfi < 0)
 513     {
 514       pop_close (server);
 515       error ("Error in open: %s, %s", strerror (errno), outfile);
 516       return (1);
 517     }
 518   fchown (mbfi, getuid (), -1);
 519
 520   if ((mbf = fdopen (mbfi, "w")) == NULL)
 521     {
 522       pop_close (server);
 523       error ("Error in fdopen: %s", strerror (errno));
 524       close (mbfi);
 525       unlink (outfile);
 526       return (1);
 527     }
 528
 529   for (i = 1; i <= nmsgs; i++)
 530     {
 531       mbx_delimit_begin (mbf);
 532       if (pop_retr (server, i, mbx_write, mbf) != OK)
 533         {
 534           error (Errmsg);
 535           close (mbfi);
 536           return (1);
 537         }
 538       mbx_delimit_end (mbf);
 539       fflush (mbf);
 540       if (ferror (mbf))
 541         {
 542           error ("Error in fflush: %s", strerror (errno));
 543           pop_close (server);
 544           close (mbfi);
 545           return (1);
 546         }
 547     }
 548
 549   /* On AFS, a call to write only modifies the file in the local
 550    *     workstation's AFS cache.  The changes are not written to the server
 551    *      until a call to fsync or close is made.  Users with AFS home
 552    *      directories have lost mail when over quota because these checks were
 553    *      not made in previous versions of movemail. */
 554
 555 #ifdef BSD
 556   if (fsync (mbfi) < 0)
 557     {
 558       error ("Error in fsync: %s", strerror (errno));
 559       return (1);
 560     }
 561 #endif
 562
 563   if (close (mbfi) == -1)
 564     {
 565       error ("Error in close: %s", strerror (errno));
 566       return (1);
 567     }
 568
 569   for (i = 1; i <= nmsgs; i++)
 570     {
 571       if (pop_delete (server, i))
 572         {
 573           error (pop_error);
 574           pop_close (server);
 575           return (1);
 576         }
 577     }
 578
 579   if (pop_quit (server))
 580     {
 581       error (pop_error);
 582       return (1);
 583     }
 584
 585   return (0);
 586 }
 587
 588 pop_retr (server, msgno, action, arg)
 589      popserver server;
 590      int (*action)();
 591 {
 592   extern char *strerror ();
 593   char *line;
 594   int ret;
 595
 596   if (pop_retrieve_first (server, msgno, &line))
 597     {
 598       strncpy (Errmsg, pop_error, sizeof (Errmsg));
 599       Errmsg[sizeof (Errmsg)-1] = '\0';
 600       return (NOTOK);
 601     }
 602
 603   while (! (ret = pop_retrieve_next (server, &line)))
 604     {
 605       if (! line)
 606         break;
 607
 608       if ((*action)(line, arg) != OK)
 609         {
 610           strcpy (Errmsg, strerror (errno));
 611           pop_close (server);
 612           return (NOTOK);
 613         }
 614     }
 615
 616   if (ret)
 617     {
 618       strncpy (Errmsg, pop_error, sizeof (Errmsg));
 619       Errmsg[sizeof (Errmsg)-1] = '\0';
 620       return (NOTOK);
 621     }
 622
 623   return (OK);
 624 }
 625
 626 /* Do this as a macro instead of using strcmp to save on execution time. */
 627 #define IS_FROM_LINE(a) ((a[0] == 'F') \
 628                          && (a[1] == 'r') \
 629                          && (a[2] == 'o') \
 630                          && (a[3] == 'm') \
 631                          && (a[4] == ' '))
 632
 633 int
 634 mbx_write (line, mbf)
 635      char *line;
 636      FILE *mbf;
 637 {
 638   if (IS_FROM_LINE (line))
 639     {
 640       if (fputc ('>', mbf) == EOF)
 641         return (NOTOK);
 642     }
 643   if (fputs (line, mbf) == EOF)
 644     return (NOTOK);
 645   if (fputc (0x0a, mbf) == EOF)
 646     return (NOTOK);
 647   return (OK);
 648 }
 649
 650 int
 651 mbx_delimit_begin (mbf)
 652      FILE *mbf;
 653 {
 654   if (fputs ("\f\n0, unseen,,\n", mbf) == EOF)
 655     return (NOTOK);
 656   return (OK);
 657 }
 658
 659 mbx_delimit_end (mbf)
 660      FILE *mbf;
 661 {
 662   if (putc ('\037', mbf) == EOF)
 663     return (NOTOK);
 664   return (OK);
 665 }
 666
 667 #endif /* MAIL_USE_POP */
 668 \f
 669 #ifndef HAVE_STRERROR
 670 char *
 671 strerror (errnum)
 672      int errnum;
 673 {
 674   extern char *sys_errlist[];
 675   extern int sys_nerr;
 676
 677   if (errnum >= 0 && errnum < sys_nerr)
 678     return sys_errlist[errnum];
 679   return (char *) "Unknown error";
 680 }
 681
 682 #endif /* ! HAVE_STRERROR */