Dogcows Code - chaz/tar/blob - src/rmt.c

   1 /* Remote connection server.
   2
   3    Copyright (C) 1994, 1995, 1996, 1997, 1999, 2000, 2001 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  14    Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License along
  17    with this program; if not, write to the Free Software Foundation, Inc.,
  18    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /* Copyright (C) 1983 Regents of the University of California.
  21    All rights reserved.
  22
  23    Redistribution and use in source and binary forms are permitted provided
  24    that the above copyright notice and this paragraph are duplicated in all
  25    such forms and that any documentation, advertising materials, and other
  26    materials related to such distribution and use acknowledge that the
  27    software was developed by the University of California, Berkeley.  The
  28    name of the University may not be used to endorse or promote products
  29    derived from this software without specific prior written permission.
  30    THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  31    WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  32    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  */
  33
  34 #include "system.h"
  35 #include <print-copyr.h>
  36 #include <localedir.h>
  37 #include <safe-read.h>
  38 #include <full-write.h>
  39
  40 #include <getopt.h>
  41 #include <sys/socket.h>
  42
  43 #ifndef EXIT_FAILURE
  44 # define EXIT_FAILURE 1
  45 #endif
  46 #ifndef EXIT_SUCCESS
  47 # define EXIT_SUCCESS 0
  48 #endif
  49
  50 /* Maximum size of a string from the requesting program.  */
  51 #define STRING_SIZE 64
  52
  53 /* Name of executing program.  */
  54 const char *program_name;
  55
  56 /* File descriptor of the tape device, or negative if none open.  */
  57 static int tape = -1;
  58
  59 /* Buffer containing transferred data, and its allocated size.  */
  60 static char *record_buffer;
  61 static size_t allocated_size;
  62
  63 /* Buffer for constructing the reply.  */
  64 static char reply_buffer[BUFSIZ];
  65
  66 /* Debugging tools.  */
  67
  68 static FILE *debug_file;
  69
  70 #define DEBUG(File) \
  71   if (debug_file) fprintf(debug_file, File)
  72
  73 #define DEBUG1(File, Arg) \
  74   if (debug_file) fprintf(debug_file, File, Arg)
  75
  76 #define DEBUG2(File, Arg1, Arg2) \
  77   if (debug_file) fprintf(debug_file, File, Arg1, Arg2)
  78
  79 /* Return an error string, given an error number.  */
  80 #if HAVE_STRERROR
  81 # ifndef strerror
  82 char *strerror ();
  83 # endif
  84 #else
  85 static char *
  86 private_strerror (int errnum)
  87 {
  88   extern char *sys_errlist[];
  89   extern int sys_nerr;
  90
  91   if (errnum > 0 && errnum <= sys_nerr)
  92     return _(sys_errlist[errnum]);
  93   return _("Unknown system error");
  94 }
  95 # define strerror private_strerror
  96 #endif
  97
  98 static void
  99 report_error_message (const char *string)
 100 {
 101   DEBUG1 ("rmtd: E 0 (%s)\n", string);
 102
 103   sprintf (reply_buffer, "E0\n%s\n", string);
 104   full_write (STDOUT_FILENO, reply_buffer, strlen (reply_buffer));
 105 }
 106
 107 static void
 108 report_numbered_error (int num)
 109 {
 110   DEBUG2 ("rmtd: E %d (%s)\n", num, strerror (num));
 111
 112   sprintf (reply_buffer, "E%d\n%s\n", num, strerror (num));
 113   full_write (STDOUT_FILENO, reply_buffer, strlen (reply_buffer));
 114 }
 115
 116 static void
 117 get_string (char *string)
 118 {
 119   int counter;
 120
 121   for (counter = 0; counter < STRING_SIZE; counter++)
 122     {
 123       if (safe_read (STDIN_FILENO, string + counter, 1) != 1)
 124         exit (EXIT_SUCCESS);
 125
 126       if (string[counter] == '\n')
 127         break;
 128     }
 129   string[counter] = '\0';
 130 }
 131
 132 static void
 133 prepare_record_buffer (size_t size)
 134 {
 135   if (size <= allocated_size)
 136     return;
 137
 138   if (record_buffer)
 139     free (record_buffer);
 140
 141   record_buffer = malloc (size);
 142
 143   if (! record_buffer)
 144     {
 145       DEBUG (_("rmtd: Cannot allocate buffer space\n"));
 146
 147       report_error_message (N_("Cannot allocate buffer space"));
 148       exit (EXIT_FAILURE);      /* exit status used to be 4 */
 149     }
 150
 151   allocated_size = size;
 152
 153 #ifdef SO_RCVBUF
 154   while (size > 1024 &&
 155          (setsockopt (STDIN_FILENO, SOL_SOCKET, SO_RCVBUF,
 156                       (char *) &size, sizeof size)
 157           < 0))
 158     size -= 1024;
 159 #else
 160   /* FIXME: I do not see any purpose to the following line...  Sigh! */
 161   size = 1 + ((size - 1) % 1024);
 162 #endif
 163 }
 164
 165 /* Decode OFLAG_STRING, which represents the 2nd argument to `open'.
 166    OFLAG_STRING should contain an optional integer, followed by an optional
 167    symbolic representation of an open flag using only '|' to separate its
 168    components (e.g. "O_WRONLY|O_CREAT|O_TRUNC").  Prefer the symbolic
 169    representation if available, falling back on the numeric
 170    representation, or to zero if both formats are absent.
 171
 172    This function should be the inverse of encode_oflag.  The numeric
 173    representation is not portable from one host to another, but it is
 174    for backward compatibility with old-fashioned clients that do not
 175    emit symbolic open flags.  */
 176
 177 static int
 178 decode_oflag (char const *oflag_string)
 179 {
 180   char *oflag_num_end;
 181   int numeric_oflag = strtol (oflag_string, &oflag_num_end, 10);
 182   int symbolic_oflag = 0;
 183
 184   oflag_string = oflag_num_end;
 185   while (ISSPACE ((unsigned char) *oflag_string))
 186     oflag_string++;
 187
 188   do
 189     {
 190       struct name_value_pair { char const *name; int value; };
 191       static struct name_value_pair const table[] =
 192       {
 193 #ifdef O_APPEND
 194         {"APPEND", O_APPEND},
 195 #endif
 196         {"CREAT", O_CREAT},
 197 #ifdef O_DSYNC
 198         {"DSYNC", O_DSYNC},
 199 #endif
 200         {"EXCL", O_EXCL},
 201 #ifdef O_LARGEFILE
 202         {"LARGEFILE", O_LARGEFILE}, /* LFS extension for opening large files */
 203 #endif
 204 #ifdef O_NOCTTY
 205         {"NOCTTY", O_NOCTTY},
 206 #endif
 207 #ifdef O_NONBLOCK
 208         {"NONBLOCK", O_NONBLOCK},
 209 #endif
 210         {"RDONLY", O_RDONLY},
 211         {"RDWR", O_RDWR},
 212 #ifdef O_RSYNC
 213         {"RSYNC", O_RSYNC},
 214 #endif
 215 #ifdef O_SYNC
 216         {"SYNC", O_SYNC},
 217 #endif
 218         {"TRUNC", O_TRUNC},
 219         {"WRONLY", O_WRONLY}
 220       };
 221       struct name_value_pair const *t;
 222       size_t s;
 223
 224       if (*oflag_string++ != 'O' || *oflag_string++ != '_')
 225         return numeric_oflag;
 226
 227       for (t = table;
 228            (strncmp (oflag_string, t->name, s = strlen (t->name)) != 0
 229             || (oflag_string[s]
 230                 && strchr ("ABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789",
 231                            oflag_string[s])));
 232            t++)
 233         if (t == table + sizeof table / sizeof *table - 1)
 234           return numeric_oflag;
 235
 236       symbolic_oflag |= t->value;
 237       oflag_string += s;
 238     }
 239   while (*oflag_string++ == '|');
 240
 241   return symbolic_oflag;
 242 }
 243
 244 static struct option const long_opts[] =
 245 {
 246   {"help", no_argument, 0, 'h'},
 247   {"version", no_argument, 0, 'v'},
 248   {0, 0, 0, 0}
 249 };
 250
 251 static void
 252 usage (int status)
 253 {
 254   if (status != EXIT_SUCCESS)
 255     fprintf (stderr, _("Try `%s --help' for more information.\n"),
 256              program_name);
 257   else
 258     {
 259       printf (_("\
 260 Usage: %s [OPTION]\n\
 261 Manipulate a tape drive, accepting commands from a remote process.\n\
 262 \n\
 263   --version  Output version info.\n\
 264   --help  Output this help.\n"),
 265               program_name);
 266       fputs (_("\nReport bugs to <bug-tar@gnu.org>.\n"), stdout);
 267     }
 268
 269   exit (status);
 270 }
 271
 272 int
 273 main (int argc, char *const *argv)
 274 {
 275   char command;
 276   ssize_t status;
 277
 278   /* FIXME: Localization is meaningless, unless --help and --version are
 279      locally used.  Localization would be best accomplished by the calling
 280      tar, on messages found within error packets.  */
 281
 282   program_name = argv[0];
 283   setlocale (LC_ALL, "");
 284   bindtextdomain (PACKAGE, LOCALEDIR);
 285   textdomain (PACKAGE);
 286
 287   switch (getopt_long (argc, argv, "", long_opts, NULL))
 288     {
 289     default:
 290       usage (EXIT_FAILURE);
 291
 292     case 'h':
 293       usage (EXIT_SUCCESS);
 294
 295     case 'v':
 296       {
 297         printf ("rmt (GNU %s) %s\n", PACKAGE, VERSION);
 298         print_copyright ("2001 Free Software Foundation, Inc.");
 299         puts (_("\
 300 This program comes with NO WARRANTY, to the extent permitted by law.\n\
 301 You may redistribute it under the terms of the GNU General Public License;\n\
 302 see the file named COPYING for details."));
 303       }
 304       return EXIT_SUCCESS;
 305
 306     case -1:
 307       break;
 308     }
 309
 310   if (optind < argc)
 311     {
 312       if (optind != argc - 1)
 313         usage (EXIT_FAILURE);
 314       debug_file = fopen (argv[optind], "w");
 315       if (debug_file == 0)
 316         {
 317           report_numbered_error (errno);
 318           exit (EXIT_FAILURE);
 319         }
 320       setbuf (debug_file, 0);
 321     }
 322
 323 top:
 324   errno = 0;
 325   status = 0;
 326   if (safe_read (STDIN_FILENO, &command, 1) != 1)
 327     return EXIT_SUCCESS;
 328
 329   switch (command)
 330     {
 331       /* FIXME: Maybe 'H' and 'V' for --help and --version output?  */
 332
 333     case 'O':
 334       {
 335         char device_string[STRING_SIZE];
 336         char oflag_string[STRING_SIZE];
 337
 338         get_string (device_string);
 339         get_string (oflag_string);
 340         DEBUG2 ("rmtd: O %s %s\n", device_string, oflag_string);
 341
 342         if (tape >= 0)
 343           close (tape);
 344
 345         tape = open (device_string, decode_oflag (oflag_string), MODE_RW);
 346         if (tape < 0)
 347           goto ioerror;
 348         goto respond;
 349       }
 350
 351     case 'C':
 352       {
 353         char device_string[STRING_SIZE];
 354
 355         get_string (device_string); /* discard */
 356         DEBUG ("rmtd: C\n");
 357
 358         if (close (tape) < 0)
 359           goto ioerror;
 360         tape = -1;
 361         goto respond;
 362       }
 363
 364     case 'L':
 365       {
 366         char count_string[STRING_SIZE];
 367         char position_string[STRING_SIZE];
 368         off_t count = 0;
 369         int negative;
 370         int whence;
 371         char *p;
 372
 373         get_string (count_string);
 374         get_string (position_string);
 375         DEBUG2 ("rmtd: L %s %s\n", count_string, position_string);
 376
 377         /* Parse count_string, taking care to check for overflow.
 378            We can't use standard functions,
 379            since off_t might be longer than long.  */
 380
 381         for (p = count_string;  *p == ' ' || *p == '\t';  p++)
 382           continue;
 383
 384         negative = *p == '-';
 385         p += negative || *p == '+';
 386
 387         for (;;)
 388           {
 389             int digit = *p++ - '0';
 390             if (9 < (unsigned) digit)
 391               break;
 392             else
 393               {
 394                 off_t c10 = 10 * count;
 395                 off_t nc = negative ? c10 - digit : c10 + digit;
 396                 if (c10 / 10 != count || (negative ? c10 < nc : nc < c10))
 397                   {
 398                     report_error_message (N_("Seek offset out of range"));
 399                     exit (EXIT_FAILURE);
 400                   }
 401                 count = nc;
 402               }
 403           }
 404
 405         switch (atoi (position_string))
 406           {
 407           case 0: whence = SEEK_SET; break;
 408           case 1: whence = SEEK_CUR; break;
 409           case 2: whence = SEEK_END; break;
 410           default:
 411             report_error_message (N_("Seek direction out of range"));
 412             exit (EXIT_FAILURE);
 413           }
 414         count = lseek (tape, count, whence);
 415         if (count < 0)
 416           goto ioerror;
 417
 418         /* Convert count back to string for reply.
 419            We can't use sprintf, since off_t might be longer than long.  */
 420         p = count_string + sizeof count_string;
 421         *--p = '\0';
 422         do
 423           *--p = '0' + (int) (count % 10);
 424         while ((count /= 10) != 0);
 425
 426         DEBUG1 ("rmtd: A %s\n", p);
 427
 428         sprintf (reply_buffer, "A%s\n", p);
 429         full_write (STDOUT_FILENO, reply_buffer, strlen (reply_buffer));
 430         goto top;
 431       }
 432
 433     case 'W':
 434       {
 435         char count_string[STRING_SIZE];
 436         size_t size;
 437         size_t counter;
 438
 439         get_string (count_string);
 440         size = atol (count_string);
 441         DEBUG1 ("rmtd: W %s\n", count_string);
 442
 443         prepare_record_buffer (size);
 444         for (counter = 0; counter < size; counter += status)
 445           {
 446             status = safe_read (STDIN_FILENO, &record_buffer[counter],
 447                                 size - counter);
 448             if (status <= 0)
 449               {
 450                 DEBUG (_("rmtd: Premature eof\n"));
 451
 452                 report_error_message (N_("Premature end of file"));
 453                 exit (EXIT_FAILURE); /* exit status used to be 2 */
 454               }
 455           }
 456         status = full_write (tape, record_buffer, size);
 457         if (status < 0)
 458           goto ioerror;
 459         goto respond;
 460       }
 461
 462     case 'R':
 463       {
 464         char count_string[STRING_SIZE];
 465         size_t size;
 466
 467         get_string (count_string);
 468         DEBUG1 ("rmtd: R %s\n", count_string);
 469
 470         size = atol (count_string);
 471         prepare_record_buffer (size);
 472         status = safe_read (tape, record_buffer, size);
 473         if (status < 0)
 474           goto ioerror;
 475         sprintf (reply_buffer, "A%ld\n", (long) status);
 476         full_write (STDOUT_FILENO, reply_buffer, strlen (reply_buffer));
 477         full_write (STDOUT_FILENO, record_buffer, status);
 478         goto top;
 479       }
 480
 481     case 'I':
 482       {
 483         char operation_string[STRING_SIZE];
 484         char count_string[STRING_SIZE];
 485
 486         get_string (operation_string);
 487         get_string  (count_string);
 488         DEBUG2 ("rmtd: I %s %s\n", operation_string, count_string);
 489
 490 #ifdef MTIOCTOP
 491         {
 492           struct mtop mtop;
 493           const char *p;
 494           off_t count = 0;
 495           int negative;
 496
 497           /* Parse count_string, taking care to check for overflow.
 498              We can't use standard functions,
 499              since off_t might be longer than long.  */
 500
 501           for (p = count_string;  *p == ' ' || *p == '\t';  p++)
 502             continue;
 503
 504           negative = *p == '-';
 505           p += negative || *p == '+';
 506
 507           for (;;)
 508             {
 509               int digit = *p++ - '0';
 510               if (9 < (unsigned) digit)
 511                 break;
 512               else
 513                 {
 514                   off_t c10 = 10 * count;
 515                   off_t nc = negative ? c10 - digit : c10 + digit;
 516                   if (c10 / 10 != count || (negative ? c10 < nc : nc < c10))
 517                     {
 518                       report_error_message (N_("Seek offset out of range"));
 519                       exit (EXIT_FAILURE);
 520                     }
 521                   count = nc;
 522                 }
 523             }
 524
 525           mtop.mt_count = count;
 526           if (mtop.mt_count != count)
 527             {
 528               report_error_message (N_("Seek offset out of range"));
 529               exit (EXIT_FAILURE);
 530             }
 531           mtop.mt_op = atoi (operation_string);
 532
 533           if (ioctl (tape, MTIOCTOP, (char *) &mtop) < 0)
 534             goto ioerror;
 535         }
 536 #endif
 537         goto respond;
 538       }
 539
 540     case 'S':                   /* status */
 541       {
 542         DEBUG ("rmtd: S\n");
 543
 544 #ifdef MTIOCGET
 545         {
 546           struct mtget operation;
 547
 548           if (ioctl (tape, MTIOCGET, (char *) &operation) < 0)
 549             goto ioerror;
 550           status = sizeof operation;
 551           sprintf (reply_buffer, "A%ld\n", (long) status);
 552           full_write (STDOUT_FILENO, reply_buffer, strlen (reply_buffer));
 553           full_write (STDOUT_FILENO, (char *) &operation, sizeof operation);
 554         }
 555 #endif
 556         goto top;
 557       }
 558
 559     default:
 560       DEBUG1 (_("rmtd: Garbage command %c\n"), command);
 561
 562       report_error_message (N_("Garbage command"));
 563       exit (EXIT_FAILURE);      /* exit status used to be 3 */
 564     }
 565
 566 respond:
 567   DEBUG1 ("rmtd: A %ld\n", (long) status);
 568
 569   sprintf (reply_buffer, "A%ld\n", (long) status);
 570   full_write (STDOUT_FILENO, reply_buffer, strlen (reply_buffer));
 571   goto top;
 572
 573 ioerror:
 574   report_numbered_error (errno);
 575   goto top;
 576 }