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

   1 /* System-dependent calls for tar.
   2
   3    Copyright (C) 2003, 2004, 2005, 2006, 2007,
   4    2008 Free Software 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 3, 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    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 #include <system.h>
  21
  22 #include "common.h"
  23 #include <rmt.h>
  24 #include <signal.h>
  25
  26 #if MSDOS
  27
  28 bool
  29 sys_get_archive_stat (void)
  30 {
  31   return 0;
  32 }
  33
  34 bool
  35 sys_file_is_archive (struct tar_stat_info *p)
  36 {
  37   return false;
  38 }
  39
  40 void
  41 sys_save_archive_dev_ino (void)
  42 {
  43 }
  44
  45 void
  46 sys_detect_dev_null_output (void)
  47 {
  48   static char const dev_null[] = "nul";
  49
  50   dev_null_output = (strcmp (archive_name_array[0], dev_null) == 0
  51                      || (! _isrmt (archive)));
  52 }
  53
  54 void
  55 sys_wait_for_child (pid_t child_pid, bool eof)
  56 {
  57 }
  58
  59 void
  60 sys_spawn_shell (void)
  61 {
  62   spawnl (P_WAIT, getenv ("COMSPEC"), "-", 0);
  63 }
  64
  65 /* stat() in djgpp's C library gives a constant number of 42 as the
  66    uid and gid of a file.  So, comparing an FTP'ed archive just after
  67    unpack would fail on MSDOS.  */
  68
  69 bool
  70 sys_compare_uid (struct stat *a, struct stat *b)
  71 {
  72   return true;
  73 }
  74
  75 bool
  76 sys_compare_gid (struct stat *a, struct stat *b)
  77 {
  78   return true;
  79 }
  80
  81 void
  82 sys_compare_links (struct stat *link_data, struct stat *stat_data)
  83 {
  84   return true;
  85 }
  86
  87 int
  88 sys_truncate (int fd)
  89 {
  90   return write (fd, "", 0);
  91 }
  92
  93 size_t
  94 sys_write_archive_buffer (void)
  95 {
  96   return full_write (archive, record_start->buffer, record_size);
  97 }
  98
  99 /* Set ARCHIVE for writing, then compressing an archive.  */
 100 void
 101 sys_child_open_for_compress (void)
 102 {
 103   FATAL_ERROR ((0, 0, _("Cannot use compressed or remote archives")));
 104 }
 105
 106 /* Set ARCHIVE for uncompressing, then reading an archive.  */
 107 void
 108 sys_child_open_for_uncompress (void)
 109 {
 110   FATAL_ERROR ((0, 0, _("Cannot use compressed or remote archives")));
 111 }
 112
 113 #else
 114
 115 extern union block *record_start; /* FIXME */
 116
 117 static struct stat archive_stat; /* stat block for archive file */
 118
 119 bool
 120 sys_get_archive_stat (void)
 121 {
 122   return fstat (archive, &archive_stat) == 0;
 123 }
 124
 125 bool
 126 sys_file_is_archive (struct tar_stat_info *p)
 127 {
 128   return (ar_dev && p->stat.st_dev == ar_dev && p->stat.st_ino == ar_ino);
 129 }
 130
 131 /* Save archive file inode and device numbers */
 132 void
 133 sys_save_archive_dev_ino (void)
 134 {
 135   if (!_isrmt (archive) && S_ISREG (archive_stat.st_mode))
 136     {
 137       ar_dev = archive_stat.st_dev;
 138       ar_ino = archive_stat.st_ino;
 139     }
 140   else
 141     ar_dev = 0;
 142 }
 143
 144 /* Detect if outputting to "/dev/null".  */
 145 void
 146 sys_detect_dev_null_output (void)
 147 {
 148   static char const dev_null[] = "/dev/null";
 149   struct stat dev_null_stat;
 150
 151   dev_null_output = (strcmp (archive_name_array[0], dev_null) == 0
 152                      || (! _isrmt (archive)
 153                          && S_ISCHR (archive_stat.st_mode)
 154                          && stat (dev_null, &dev_null_stat) == 0
 155                          && archive_stat.st_dev == dev_null_stat.st_dev
 156                          && archive_stat.st_ino == dev_null_stat.st_ino));
 157 }
 158
 159 void
 160 sys_wait_for_child (pid_t child_pid, bool eof)
 161 {
 162   if (child_pid)
 163     {
 164       int wait_status;
 165
 166       while (waitpid (child_pid, &wait_status, 0) == -1)
 167         if (errno != EINTR)
 168           {
 169             waitpid_error (use_compress_program_option);
 170             break;
 171           }
 172
 173       if (WIFSIGNALED (wait_status))
 174         {
 175           int sig = WTERMSIG (wait_status);
 176           if (!(!eof && sig == SIGPIPE))
 177             ERROR ((0, 0, _("Child died with signal %d"), sig));
 178         }
 179       else if (WEXITSTATUS (wait_status) != 0)
 180         ERROR ((0, 0, _("Child returned status %d"),
 181                 WEXITSTATUS (wait_status)));
 182     }
 183 }
 184
 185 void
 186 sys_spawn_shell (void)
 187 {
 188   pid_t child;
 189   const char *shell = getenv ("SHELL");
 190   if (! shell)
 191     shell = "/bin/sh";
 192   child = xfork ();
 193   if (child == 0)
 194     {
 195       execlp (shell, "-sh", "-i", (char *) 0);
 196       exec_fatal (shell);
 197     }
 198   else
 199     {
 200       int wait_status;
 201       while (waitpid (child, &wait_status, 0) == -1)
 202         if (errno != EINTR)
 203           {
 204             waitpid_error (shell);
 205             break;
 206           }
 207     }
 208 }
 209
 210 bool
 211 sys_compare_uid (struct stat *a, struct stat *b)
 212 {
 213   return a->st_uid == b->st_uid;
 214 }
 215
 216 bool
 217 sys_compare_gid (struct stat *a, struct stat *b)
 218 {
 219   return a->st_gid == b->st_gid;
 220 }
 221
 222 bool
 223 sys_compare_links (struct stat *link_data, struct stat *stat_data)
 224 {
 225   return stat_data->st_dev == link_data->st_dev
 226          && stat_data->st_ino == link_data->st_ino;
 227 }
 228
 229 int
 230 sys_truncate (int fd)
 231 {
 232   off_t pos = lseek (fd, (off_t) 0, SEEK_CUR);
 233   return pos < 0 ? -1 : ftruncate (fd, pos);
 234 }
 235
 236 /* Return nonzero if NAME is the name of a regular file, or if the file
 237    does not exist (so it would be created as a regular file).  */
 238 static int
 239 is_regular_file (const char *name)
 240 {
 241   struct stat stbuf;
 242
 243   if (stat (name, &stbuf) == 0)
 244     return S_ISREG (stbuf.st_mode);
 245   else
 246     return errno == ENOENT;
 247 }
 248
 249 size_t
 250 sys_write_archive_buffer (void)
 251 {
 252   return rmtwrite (archive, record_start->buffer, record_size);
 253 }
 254
 255 #define PREAD 0                 /* read file descriptor from pipe() */
 256 #define PWRITE 1                /* write file descriptor from pipe() */
 257
 258 /* Duplicate file descriptor FROM into becoming INTO.
 259    INTO is closed first and has to be the next available slot.  */
 260 static void
 261 xdup2 (int from, int into)
 262 {
 263   if (from != into)
 264     {
 265       int status = close (into);
 266
 267       if (status != 0 && errno != EBADF)
 268         {
 269           int e = errno;
 270           FATAL_ERROR ((0, e, _("Cannot close")));
 271         }
 272       status = dup (from);
 273       if (status != into)
 274         {
 275           if (status < 0)
 276             {
 277               int e = errno;
 278               FATAL_ERROR ((0, e, _("Cannot dup")));
 279             }
 280           abort ();
 281         }
 282       xclose (from);
 283     }
 284 }
 285
 286 /* Set ARCHIVE for writing, then compressing an archive.  */
 287 pid_t
 288 sys_child_open_for_compress (void)
 289 {
 290   int parent_pipe[2];
 291   int child_pipe[2];
 292   pid_t grandchild_pid;
 293   pid_t child_pid;
 294   int wait_status;
 295
 296   xpipe (parent_pipe);
 297   child_pid = xfork ();
 298
 299   if (child_pid > 0)
 300     {
 301       /* The parent tar is still here!  Just clean up.  */
 302
 303       archive = parent_pipe[PWRITE];
 304       xclose (parent_pipe[PREAD]);
 305       return child_pid;
 306     }
 307
 308   /* The new born child tar is here!  */
 309
 310   program_name = _("tar (child)");
 311
 312   xdup2 (parent_pipe[PREAD], STDIN_FILENO);
 313   xclose (parent_pipe[PWRITE]);
 314
 315   /* Check if we need a grandchild tar.  This happens only if either:
 316      a) the file is to be accessed by rmt: compressor doesn't know how;
 317      b) the file is not a plain file.  */
 318
 319   if (!_remdev (archive_name_array[0])
 320       && is_regular_file (archive_name_array[0]))
 321     {
 322       if (backup_option)
 323         maybe_backup_file (archive_name_array[0], 1);
 324
 325       /* We don't need a grandchild tar.  Open the archive and launch the
 326          compressor.  */
 327       if (strcmp (archive_name_array[0], "-"))
 328         {
 329           archive = creat (archive_name_array[0], MODE_RW);
 330           if (archive < 0)
 331             {
 332               int saved_errno = errno;
 333
 334               if (backup_option)
 335                 undo_last_backup ();
 336               errno = saved_errno;
 337               open_fatal (archive_name_array[0]);
 338             }
 339           xdup2 (archive, STDOUT_FILENO);
 340         }
 341       execlp (use_compress_program_option, use_compress_program_option, NULL);
 342       exec_fatal (use_compress_program_option);
 343     }
 344
 345   /* We do need a grandchild tar.  */
 346
 347   xpipe (child_pipe);
 348   grandchild_pid = xfork ();
 349
 350   if (grandchild_pid == 0)
 351     {
 352       /* The newborn grandchild tar is here!  Launch the compressor.  */
 353
 354       program_name = _("tar (grandchild)");
 355
 356       xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
 357       xclose (child_pipe[PREAD]);
 358       execlp (use_compress_program_option, use_compress_program_option,
 359               (char *) 0);
 360       exec_fatal (use_compress_program_option);
 361     }
 362
 363   /* The child tar is still here!  */
 364
 365   /* Prepare for reblocking the data from the compressor into the archive.  */
 366
 367   xdup2 (child_pipe[PREAD], STDIN_FILENO);
 368   xclose (child_pipe[PWRITE]);
 369
 370   if (strcmp (archive_name_array[0], "-") == 0)
 371     archive = STDOUT_FILENO;
 372   else
 373     {
 374       archive = rmtcreat (archive_name_array[0], MODE_RW, rsh_command_option);
 375       if (archive < 0)
 376         open_fatal (archive_name_array[0]);
 377     }
 378
 379   /* Let's read out of the stdin pipe and write an archive.  */
 380
 381   while (1)
 382     {
 383       size_t status = 0;
 384       char *cursor;
 385       size_t length;
 386
 387       /* Assemble a record.  */
 388
 389       for (length = 0, cursor = record_start->buffer;
 390            length < record_size;
 391            length += status, cursor += status)
 392         {
 393           size_t size = record_size - length;
 394
 395           status = safe_read (STDIN_FILENO, cursor, size);
 396           if (status == SAFE_READ_ERROR)
 397             read_fatal (use_compress_program_option);
 398           if (status == 0)
 399             break;
 400         }
 401
 402       /* Copy the record.  */
 403
 404       if (status == 0)
 405         {
 406           /* We hit the end of the file.  Write last record at
 407              full length, as the only role of the grandchild is
 408              doing proper reblocking.  */
 409
 410           if (length > 0)
 411             {
 412               memset (record_start->buffer + length, 0, record_size - length);
 413               status = sys_write_archive_buffer ();
 414               if (status != record_size)
 415                 archive_write_error (status);
 416             }
 417
 418           /* There is nothing else to read, break out.  */
 419           break;
 420         }
 421
 422       status = sys_write_archive_buffer ();
 423       if (status != record_size)
 424         archive_write_error (status);
 425     }
 426
 427   /* Propagate any failure of the grandchild back to the parent.  */
 428
 429   while (waitpid (grandchild_pid, &wait_status, 0) == -1)
 430     if (errno != EINTR)
 431       {
 432         waitpid_error (use_compress_program_option);
 433         break;
 434       }
 435
 436   if (WIFSIGNALED (wait_status))
 437     {
 438       kill (child_pid, WTERMSIG (wait_status));
 439       exit_status = TAREXIT_FAILURE;
 440     }
 441   else if (WEXITSTATUS (wait_status) != 0)
 442     exit_status = WEXITSTATUS (wait_status);
 443
 444   exit (exit_status);
 445 }
 446
 447 /* Set ARCHIVE for uncompressing, then reading an archive.  */
 448 pid_t
 449 sys_child_open_for_uncompress (void)
 450 {
 451   int parent_pipe[2];
 452   int child_pipe[2];
 453   pid_t grandchild_pid;
 454   pid_t child_pid;
 455   int wait_status;
 456
 457   xpipe (parent_pipe);
 458   child_pid = xfork ();
 459
 460   if (child_pid > 0)
 461     {
 462       /* The parent tar is still here!  Just clean up.  */
 463
 464       archive = parent_pipe[PREAD];
 465       xclose (parent_pipe[PWRITE]);
 466       return child_pid;
 467     }
 468
 469   /* The newborn child tar is here!  */
 470
 471   program_name = _("tar (child)");
 472
 473   xdup2 (parent_pipe[PWRITE], STDOUT_FILENO);
 474   xclose (parent_pipe[PREAD]);
 475
 476   /* Check if we need a grandchild tar.  This happens only if either:
 477      a) we're reading stdin: to force unblocking;
 478      b) the file is to be accessed by rmt: compressor doesn't know how;
 479      c) the file is not a plain file.  */
 480
 481   if (strcmp (archive_name_array[0], "-") != 0
 482       && !_remdev (archive_name_array[0])
 483       && is_regular_file (archive_name_array[0]))
 484     {
 485       /* We don't need a grandchild tar.  Open the archive and lauch the
 486          uncompressor.  */
 487
 488       archive = open (archive_name_array[0], O_RDONLY | O_BINARY, MODE_RW);
 489       if (archive < 0)
 490         open_fatal (archive_name_array[0]);
 491       xdup2 (archive, STDIN_FILENO);
 492       execlp (use_compress_program_option, use_compress_program_option,
 493               "-d", (char *) 0);
 494       exec_fatal (use_compress_program_option);
 495     }
 496
 497   /* We do need a grandchild tar.  */
 498
 499   xpipe (child_pipe);
 500   grandchild_pid = xfork ();
 501
 502   if (grandchild_pid == 0)
 503     {
 504       /* The newborn grandchild tar is here!  Launch the uncompressor.  */
 505
 506       program_name = _("tar (grandchild)");
 507
 508       xdup2 (child_pipe[PREAD], STDIN_FILENO);
 509       xclose (child_pipe[PWRITE]);
 510       execlp (use_compress_program_option, use_compress_program_option,
 511               "-d", (char *) 0);
 512       exec_fatal (use_compress_program_option);
 513     }
 514
 515   /* The child tar is still here!  */
 516
 517   /* Prepare for unblocking the data from the archive into the
 518      uncompressor.  */
 519
 520   xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
 521   xclose (child_pipe[PREAD]);
 522
 523   if (strcmp (archive_name_array[0], "-") == 0)
 524     archive = STDIN_FILENO;
 525   else
 526     archive = rmtopen (archive_name_array[0], O_RDONLY | O_BINARY,
 527                        MODE_RW, rsh_command_option);
 528   if (archive < 0)
 529     open_fatal (archive_name_array[0]);
 530
 531   /* Let's read the archive and pipe it into stdout.  */
 532
 533   while (1)
 534     {
 535       char *cursor;
 536       size_t maximum;
 537       size_t count;
 538       size_t status;
 539
 540       clear_read_error_count ();
 541
 542     error_loop:
 543       status = rmtread (archive, record_start->buffer, record_size);
 544       if (status == SAFE_READ_ERROR)
 545         {
 546           archive_read_error ();
 547           goto error_loop;
 548         }
 549       if (status == 0)
 550         break;
 551       cursor = record_start->buffer;
 552       maximum = status;
 553       while (maximum)
 554         {
 555           count = maximum < BLOCKSIZE ? maximum : BLOCKSIZE;
 556           if (full_write (STDOUT_FILENO, cursor, count) != count)
 557             write_error (use_compress_program_option);
 558           cursor += count;
 559           maximum -= count;
 560         }
 561     }
 562
 563   xclose (STDOUT_FILENO);
 564
 565   /* Propagate any failure of the grandchild back to the parent.  */
 566
 567   while (waitpid (grandchild_pid, &wait_status, 0) == -1)
 568     if (errno != EINTR)
 569       {
 570         waitpid_error (use_compress_program_option);
 571         break;
 572       }
 573
 574   if (WIFSIGNALED (wait_status))
 575     {
 576       kill (child_pid, WTERMSIG (wait_status));
 577       exit_status = TAREXIT_FAILURE;
 578     }
 579   else if (WEXITSTATUS (wait_status) != 0)
 580     exit_status = WEXITSTATUS (wait_status);
 581
 582   exit (exit_status);
 583 }
 584
 585 \f
 586
 587 static void
 588 dec_to_env (char *envar, uintmax_t num)
 589 {
 590   char buf[UINTMAX_STRSIZE_BOUND];
 591   char *numstr;
 592
 593   numstr = STRINGIFY_BIGINT (num, buf);
 594   if (setenv (envar, numstr, 1) != 0)
 595     xalloc_die ();
 596 }
 597
 598 static void
 599 time_to_env (char *envar, struct timespec t)
 600 {
 601   char buf[TIMESPEC_STRSIZE_BOUND];
 602   if (setenv (envar, code_timespec (t, buf), 1) != 0)
 603     xalloc_die ();
 604 }
 605
 606 static void
 607 oct_to_env (char *envar, unsigned long num)
 608 {
 609   char buf[1+1+(sizeof(unsigned long)*CHAR_BIT+2)/3];
 610
 611   snprintf (buf, sizeof buf, "0%lo", num);
 612   if (setenv (envar, buf, 1) != 0)
 613     xalloc_die ();
 614 }
 615
 616 static void
 617 str_to_env (char *envar, char const *str)
 618 {
 619   if (str)
 620     {
 621       if (setenv (envar, str, 1) != 0)
 622         xalloc_die ();
 623     }
 624   else
 625     unsetenv (envar);
 626 }
 627
 628 static void
 629 chr_to_env (char *envar, char c)
 630 {
 631   char buf[2];
 632   buf[0] = c;
 633   buf[1] = 0;
 634   if (setenv (envar, buf, 1) != 0)
 635     xalloc_die ();
 636 }
 637
 638 static void
 639 stat_to_env (char *name, char type, struct tar_stat_info *st)
 640 {
 641   str_to_env ("TAR_VERSION", PACKAGE_VERSION);
 642   chr_to_env ("TAR_FILETYPE", type);
 643   oct_to_env ("TAR_MODE", st->stat.st_mode);
 644   str_to_env ("TAR_FILENAME", name);
 645   str_to_env ("TAR_REALNAME", st->file_name);
 646   str_to_env ("TAR_UNAME", st->uname);
 647   str_to_env ("TAR_GNAME", st->gname);
 648   time_to_env ("TAR_ATIME", st->atime);
 649   time_to_env ("TAR_MTIME", st->mtime);
 650   time_to_env ("TAR_CTIME", st->ctime);
 651   dec_to_env ("TAR_SIZE", st->stat.st_size);
 652   dec_to_env ("TAR_UID", st->stat.st_uid);
 653   dec_to_env ("TAR_GID", st->stat.st_gid);
 654
 655   switch (type)
 656     {
 657     case 'b':
 658     case 'c':
 659       dec_to_env ("TAR_MINOR", minor (st->stat.st_rdev));
 660       dec_to_env ("TAR_MAJOR", major (st->stat.st_rdev));
 661       unsetenv ("TAR_LINKNAME");
 662       break;
 663
 664     case 'l':
 665     case 'h':
 666       unsetenv ("TAR_MINOR");
 667       unsetenv ("TAR_MAJOR");
 668       str_to_env ("TAR_LINKNAME", st->link_name);
 669       break;
 670
 671     default:
 672       unsetenv ("TAR_MINOR");
 673       unsetenv ("TAR_MAJOR");
 674       unsetenv ("TAR_LINKNAME");
 675       break;
 676     }
 677 }
 678
 679 static pid_t global_pid;
 680 static RETSIGTYPE (*pipe_handler) (int sig);
 681
 682 int
 683 sys_exec_command (char *file_name, int typechar, struct tar_stat_info *st)
 684 {
 685   int p[2];
 686   char *argv[4];
 687
 688   xpipe (p);
 689   pipe_handler = signal (SIGPIPE, SIG_IGN);
 690   global_pid = xfork ();
 691
 692   if (global_pid != 0)
 693     {
 694       xclose (p[PREAD]);
 695       return p[PWRITE];
 696     }
 697
 698   /* Child */
 699   xdup2 (p[PREAD], STDIN_FILENO);
 700   xclose (p[PWRITE]);
 701
 702   stat_to_env (file_name, typechar, st);
 703
 704   argv[0] = "/bin/sh";
 705   argv[1] = "-c";
 706   argv[2] = to_command_option;
 707   argv[3] = NULL;
 708
 709   execv ("/bin/sh", argv);
 710
 711   exec_fatal (file_name);
 712 }
 713
 714 void
 715 sys_wait_command (void)
 716 {
 717   int status;
 718
 719   if (global_pid < 0)
 720     return;
 721
 722   signal (SIGPIPE, pipe_handler);
 723   while (waitpid (global_pid, &status, 0) == -1)
 724     if (errno != EINTR)
 725       {
 726         global_pid = -1;
 727         waitpid_error (to_command_option);
 728         return;
 729       }
 730
 731   if (WIFEXITED (status))
 732     {
 733       if (!ignore_command_error_option && WEXITSTATUS (status))
 734         ERROR ((0, 0, _("%lu: Child returned status %d"),
 735                 (unsigned long) global_pid, WEXITSTATUS (status)));
 736     }
 737   else if (WIFSIGNALED (status))
 738     {
 739       WARN ((0, 0, _("%lu: Child terminated on signal %d"),
 740              (unsigned long) global_pid, WTERMSIG (status)));
 741     }
 742   else
 743     ERROR ((0, 0, _("%lu: Child terminated on unknown reason"),
 744             (unsigned long) global_pid));
 745
 746   global_pid = -1;
 747 }
 748
 749 int
 750 sys_exec_info_script (const char **archive_name, int volume_number)
 751 {
 752   pid_t pid;
 753   char *argv[4];
 754   char uintbuf[UINTMAX_STRSIZE_BOUND];
 755   int p[2];
 756   static RETSIGTYPE (*saved_handler) (int sig);
 757
 758   xpipe (p);
 759   saved_handler = signal (SIGPIPE, SIG_IGN);
 760
 761   pid = xfork ();
 762
 763   if (pid != 0)
 764     {
 765       /* Master */
 766
 767       int rc;
 768       int status;
 769       char *buf = NULL;
 770       size_t size = 0;
 771       FILE *fp;
 772
 773       xclose (p[PWRITE]);
 774       fp = fdopen (p[PREAD], "r");
 775       rc = getline (&buf, &size, fp);
 776       fclose (fp);
 777
 778       if (rc > 0 && buf[rc-1] == '\n')
 779         buf[--rc] = 0;
 780
 781       while (waitpid (pid, &status, 0) == -1)
 782         if (errno != EINTR)
 783           {
 784             signal (SIGPIPE, saved_handler);
 785             waitpid_error (info_script_option);
 786             return -1;
 787           }
 788
 789       signal (SIGPIPE, saved_handler);
 790
 791       if (WIFEXITED (status))
 792         {
 793           if (WEXITSTATUS (status) == 0 && rc > 0)
 794             *archive_name = buf;
 795           else
 796             free (buf);
 797           return WEXITSTATUS (status);
 798         }
 799
 800       free (buf);
 801       return -1;
 802     }
 803
 804   /* Child */
 805   setenv ("TAR_VERSION", PACKAGE_VERSION, 1);
 806   setenv ("TAR_ARCHIVE", *archive_name, 1);
 807   setenv ("TAR_VOLUME", STRINGIFY_BIGINT (volume_number, uintbuf), 1);
 808   setenv ("TAR_BLOCKING_FACTOR",
 809           STRINGIFY_BIGINT (blocking_factor, uintbuf), 1);
 810   setenv ("TAR_SUBCOMMAND", subcommand_string (subcommand_option), 1);
 811   setenv ("TAR_FORMAT",
 812           archive_format_string (current_format == DEFAULT_FORMAT ?
 813                                  archive_format : current_format), 1);
 814   setenv ("TAR_FD", STRINGIFY_BIGINT (p[PWRITE], uintbuf), 1);
 815
 816   xclose (p[PREAD]);
 817
 818   argv[0] = "/bin/sh";
 819   argv[1] = "-c";
 820   argv[2] = (char*) info_script_option;
 821   argv[3] = NULL;
 822
 823   execv (argv[0], argv);
 824
 825   exec_fatal (info_script_option);
 826 }
 827
 828 void
 829 sys_exec_checkpoint_script (const char *script_name,
 830                             const char *archive_name,
 831                             int checkpoint_number)
 832 {
 833   pid_t pid;
 834   char *argv[4];
 835   char uintbuf[UINTMAX_STRSIZE_BOUND];
 836
 837   pid = xfork ();
 838
 839   if (pid != 0)
 840     {
 841       /* Master */
 842
 843       int status;
 844
 845       while (waitpid (pid, &status, 0) == -1)
 846         if (errno != EINTR)
 847           {
 848             waitpid_error (script_name);
 849             break;
 850           }
 851
 852       return;
 853     }
 854
 855   /* Child */
 856   setenv ("TAR_VERSION", PACKAGE_VERSION, 1);
 857   setenv ("TAR_ARCHIVE", archive_name, 1);
 858   setenv ("TAR_CHECKPOINT", STRINGIFY_BIGINT (checkpoint_number, uintbuf), 1);
 859   setenv ("TAR_BLOCKING_FACTOR",
 860           STRINGIFY_BIGINT (blocking_factor, uintbuf), 1);
 861   setenv ("TAR_SUBCOMMAND", subcommand_string (subcommand_option), 1);
 862   setenv ("TAR_FORMAT",
 863           archive_format_string (current_format == DEFAULT_FORMAT ?
 864                                  archive_format : current_format), 1);
 865   argv[0] = "/bin/sh";
 866   argv[1] = "-c";
 867   argv[2] = (char*) script_name;
 868   argv[3] = NULL;
 869
 870   execv (argv[0], argv);
 871
 872   exec_fatal (script_name);
 873 }
 874
 875 #endif /* not MSDOS */