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 void wait_for_grandchild (pid_t pid) __attribute__ ((__noreturn__));
 287
 288 /* Propagate any failure of the grandchild back to the parent.  */
 289 void
 290 wait_for_grandchild (pid_t pid)
 291 {
 292   int wait_status;
 293
 294   while (waitpid (pid, &wait_status, 0) == -1)
 295     if (errno != EINTR)
 296       {
 297         waitpid_error (use_compress_program_option);
 298         break;
 299       }
 300
 301   if (WIFSIGNALED (wait_status))
 302     raise (WTERMSIG (wait_status));
 303   else if (WEXITSTATUS (wait_status) != 0)
 304     exit_status = WEXITSTATUS (wait_status);
 305
 306   exit (exit_status);
 307 }
 308
 309 /* Set ARCHIVE for writing, then compressing an archive.  */
 310 pid_t
 311 sys_child_open_for_compress (void)
 312 {
 313   int parent_pipe[2];
 314   int child_pipe[2];
 315   pid_t grandchild_pid;
 316   pid_t child_pid;
 317
 318   xpipe (parent_pipe);
 319   child_pid = xfork ();
 320
 321   if (child_pid > 0)
 322     {
 323       /* The parent tar is still here!  Just clean up.  */
 324
 325       archive = parent_pipe[PWRITE];
 326       xclose (parent_pipe[PREAD]);
 327       return child_pid;
 328     }
 329
 330   /* The new born child tar is here!  */
 331
 332   program_name = _("tar (child)");
 333
 334   xdup2 (parent_pipe[PREAD], STDIN_FILENO);
 335   xclose (parent_pipe[PWRITE]);
 336
 337   /* Check if we need a grandchild tar.  This happens only if either:
 338      a) the file is to be accessed by rmt: compressor doesn't know how;
 339      b) the file is not a plain file.  */
 340
 341   if (!_remdev (archive_name_array[0])
 342       && is_regular_file (archive_name_array[0]))
 343     {
 344       if (backup_option)
 345         maybe_backup_file (archive_name_array[0], 1);
 346
 347       /* We don't need a grandchild tar.  Open the archive and launch the
 348          compressor.  */
 349       if (strcmp (archive_name_array[0], "-"))
 350         {
 351           archive = creat (archive_name_array[0], MODE_RW);
 352           if (archive < 0)
 353             {
 354               int saved_errno = errno;
 355
 356               if (backup_option)
 357                 undo_last_backup ();
 358               errno = saved_errno;
 359               open_fatal (archive_name_array[0]);
 360             }
 361           xdup2 (archive, STDOUT_FILENO);
 362         }
 363       execlp (use_compress_program_option, use_compress_program_option, NULL);
 364       exec_fatal (use_compress_program_option);
 365     }
 366
 367   /* We do need a grandchild tar.  */
 368
 369   xpipe (child_pipe);
 370   grandchild_pid = xfork ();
 371
 372   if (grandchild_pid == 0)
 373     {
 374       /* The newborn grandchild tar is here!  Launch the compressor.  */
 375
 376       program_name = _("tar (grandchild)");
 377
 378       xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
 379       xclose (child_pipe[PREAD]);
 380       execlp (use_compress_program_option, use_compress_program_option,
 381               (char *) 0);
 382       exec_fatal (use_compress_program_option);
 383     }
 384
 385   /* The child tar is still here!  */
 386
 387   /* Prepare for reblocking the data from the compressor into the archive.  */
 388
 389   xdup2 (child_pipe[PREAD], STDIN_FILENO);
 390   xclose (child_pipe[PWRITE]);
 391
 392   if (strcmp (archive_name_array[0], "-") == 0)
 393     archive = STDOUT_FILENO;
 394   else
 395     {
 396       archive = rmtcreat (archive_name_array[0], MODE_RW, rsh_command_option);
 397       if (archive < 0)
 398         open_fatal (archive_name_array[0]);
 399     }
 400
 401   /* Let's read out of the stdin pipe and write an archive.  */
 402
 403   while (1)
 404     {
 405       size_t status = 0;
 406       char *cursor;
 407       size_t length;
 408
 409       /* Assemble a record.  */
 410
 411       for (length = 0, cursor = record_start->buffer;
 412            length < record_size;
 413            length += status, cursor += status)
 414         {
 415           size_t size = record_size - length;
 416
 417           status = safe_read (STDIN_FILENO, cursor, size);
 418           if (status == SAFE_READ_ERROR)
 419             read_fatal (use_compress_program_option);
 420           if (status == 0)
 421             break;
 422         }
 423
 424       /* Copy the record.  */
 425
 426       if (status == 0)
 427         {
 428           /* We hit the end of the file.  Write last record at
 429              full length, as the only role of the grandchild is
 430              doing proper reblocking.  */
 431
 432           if (length > 0)
 433             {
 434               memset (record_start->buffer + length, 0, record_size - length);
 435               status = sys_write_archive_buffer ();
 436               if (status != record_size)
 437                 archive_write_error (status);
 438             }
 439
 440           /* There is nothing else to read, break out.  */
 441           break;
 442         }
 443
 444       status = sys_write_archive_buffer ();
 445       if (status != record_size)
 446         archive_write_error (status);
 447     }
 448
 449   wait_for_grandchild (grandchild_pid);
 450 }
 451
 452 /* Set ARCHIVE for uncompressing, then reading an archive.  */
 453 pid_t
 454 sys_child_open_for_uncompress (void)
 455 {
 456   int parent_pipe[2];
 457   int child_pipe[2];
 458   pid_t grandchild_pid;
 459   pid_t child_pid;
 460
 461   xpipe (parent_pipe);
 462   child_pid = xfork ();
 463
 464   if (child_pid > 0)
 465     {
 466       /* The parent tar is still here!  Just clean up.  */
 467
 468       archive = parent_pipe[PREAD];
 469       xclose (parent_pipe[PWRITE]);
 470       return child_pid;
 471     }
 472
 473   /* The newborn child tar is here!  */
 474
 475   program_name = _("tar (child)");
 476
 477   xdup2 (parent_pipe[PWRITE], STDOUT_FILENO);
 478   xclose (parent_pipe[PREAD]);
 479
 480   /* Check if we need a grandchild tar.  This happens only if either:
 481      a) we're reading stdin: to force unblocking;
 482      b) the file is to be accessed by rmt: compressor doesn't know how;
 483      c) the file is not a plain file.  */
 484
 485   if (strcmp (archive_name_array[0], "-") != 0
 486       && !_remdev (archive_name_array[0])
 487       && is_regular_file (archive_name_array[0]))
 488     {
 489       /* We don't need a grandchild tar.  Open the archive and lauch the
 490          uncompressor.  */
 491
 492       archive = open (archive_name_array[0], O_RDONLY | O_BINARY, MODE_RW);
 493       if (archive < 0)
 494         open_fatal (archive_name_array[0]);
 495       xdup2 (archive, STDIN_FILENO);
 496       execlp (use_compress_program_option, use_compress_program_option,
 497               "-d", (char *) 0);
 498       exec_fatal (use_compress_program_option);
 499     }
 500
 501   /* We do need a grandchild tar.  */
 502
 503   xpipe (child_pipe);
 504   grandchild_pid = xfork ();
 505
 506   if (grandchild_pid == 0)
 507     {
 508       /* The newborn grandchild tar is here!  Launch the uncompressor.  */
 509
 510       program_name = _("tar (grandchild)");
 511
 512       xdup2 (child_pipe[PREAD], STDIN_FILENO);
 513       xclose (child_pipe[PWRITE]);
 514       execlp (use_compress_program_option, use_compress_program_option,
 515               "-d", (char *) 0);
 516       exec_fatal (use_compress_program_option);
 517     }
 518
 519   /* The child tar is still here!  */
 520
 521   /* Prepare for unblocking the data from the archive into the
 522      uncompressor.  */
 523
 524   xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
 525   xclose (child_pipe[PREAD]);
 526
 527   if (strcmp (archive_name_array[0], "-") == 0)
 528     archive = STDIN_FILENO;
 529   else
 530     archive = rmtopen (archive_name_array[0], O_RDONLY | O_BINARY,
 531                        MODE_RW, rsh_command_option);
 532   if (archive < 0)
 533     open_fatal (archive_name_array[0]);
 534
 535   /* Let's read the archive and pipe it into stdout.  */
 536
 537   while (1)
 538     {
 539       char *cursor;
 540       size_t maximum;
 541       size_t count;
 542       size_t status;
 543
 544       clear_read_error_count ();
 545
 546     error_loop:
 547       status = rmtread (archive, record_start->buffer, record_size);
 548       if (status == SAFE_READ_ERROR)
 549         {
 550           archive_read_error ();
 551           goto error_loop;
 552         }
 553       if (status == 0)
 554         break;
 555       cursor = record_start->buffer;
 556       maximum = status;
 557       while (maximum)
 558         {
 559           count = maximum < BLOCKSIZE ? maximum : BLOCKSIZE;
 560           if (full_write (STDOUT_FILENO, cursor, count) != count)
 561             write_error (use_compress_program_option);
 562           cursor += count;
 563           maximum -= count;
 564         }
 565     }
 566
 567   xclose (STDOUT_FILENO);
 568
 569   wait_for_grandchild (grandchild_pid);
 570 }
 571
 572 \f
 573
 574 static void
 575 dec_to_env (char *envar, uintmax_t num)
 576 {
 577   char buf[UINTMAX_STRSIZE_BOUND];
 578   char *numstr;
 579
 580   numstr = STRINGIFY_BIGINT (num, buf);
 581   if (setenv (envar, numstr, 1) != 0)
 582     xalloc_die ();
 583 }
 584
 585 static void
 586 time_to_env (char *envar, struct timespec t)
 587 {
 588   char buf[TIMESPEC_STRSIZE_BOUND];
 589   if (setenv (envar, code_timespec (t, buf), 1) != 0)
 590     xalloc_die ();
 591 }
 592
 593 static void
 594 oct_to_env (char *envar, unsigned long num)
 595 {
 596   char buf[1+1+(sizeof(unsigned long)*CHAR_BIT+2)/3];
 597
 598   snprintf (buf, sizeof buf, "0%lo", num);
 599   if (setenv (envar, buf, 1) != 0)
 600     xalloc_die ();
 601 }
 602
 603 static void
 604 str_to_env (char *envar, char const *str)
 605 {
 606   if (str)
 607     {
 608       if (setenv (envar, str, 1) != 0)
 609         xalloc_die ();
 610     }
 611   else
 612     unsetenv (envar);
 613 }
 614
 615 static void
 616 chr_to_env (char *envar, char c)
 617 {
 618   char buf[2];
 619   buf[0] = c;
 620   buf[1] = 0;
 621   if (setenv (envar, buf, 1) != 0)
 622     xalloc_die ();
 623 }
 624
 625 static void
 626 stat_to_env (char *name, char type, struct tar_stat_info *st)
 627 {
 628   str_to_env ("TAR_VERSION", PACKAGE_VERSION);
 629   chr_to_env ("TAR_FILETYPE", type);
 630   oct_to_env ("TAR_MODE", st->stat.st_mode);
 631   str_to_env ("TAR_FILENAME", name);
 632   str_to_env ("TAR_REALNAME", st->file_name);
 633   str_to_env ("TAR_UNAME", st->uname);
 634   str_to_env ("TAR_GNAME", st->gname);
 635   time_to_env ("TAR_ATIME", st->atime);
 636   time_to_env ("TAR_MTIME", st->mtime);
 637   time_to_env ("TAR_CTIME", st->ctime);
 638   dec_to_env ("TAR_SIZE", st->stat.st_size);
 639   dec_to_env ("TAR_UID", st->stat.st_uid);
 640   dec_to_env ("TAR_GID", st->stat.st_gid);
 641
 642   switch (type)
 643     {
 644     case 'b':
 645     case 'c':
 646       dec_to_env ("TAR_MINOR", minor (st->stat.st_rdev));
 647       dec_to_env ("TAR_MAJOR", major (st->stat.st_rdev));
 648       unsetenv ("TAR_LINKNAME");
 649       break;
 650
 651     case 'l':
 652     case 'h':
 653       unsetenv ("TAR_MINOR");
 654       unsetenv ("TAR_MAJOR");
 655       str_to_env ("TAR_LINKNAME", st->link_name);
 656       break;
 657
 658     default:
 659       unsetenv ("TAR_MINOR");
 660       unsetenv ("TAR_MAJOR");
 661       unsetenv ("TAR_LINKNAME");
 662       break;
 663     }
 664 }
 665
 666 static pid_t global_pid;
 667 static RETSIGTYPE (*pipe_handler) (int sig);
 668
 669 int
 670 sys_exec_command (char *file_name, int typechar, struct tar_stat_info *st)
 671 {
 672   int p[2];
 673   char *argv[4];
 674
 675   xpipe (p);
 676   pipe_handler = signal (SIGPIPE, SIG_IGN);
 677   global_pid = xfork ();
 678
 679   if (global_pid != 0)
 680     {
 681       xclose (p[PREAD]);
 682       return p[PWRITE];
 683     }
 684
 685   /* Child */
 686   xdup2 (p[PREAD], STDIN_FILENO);
 687   xclose (p[PWRITE]);
 688
 689   stat_to_env (file_name, typechar, st);
 690
 691   argv[0] = "/bin/sh";
 692   argv[1] = "-c";
 693   argv[2] = to_command_option;
 694   argv[3] = NULL;
 695
 696   execv ("/bin/sh", argv);
 697
 698   exec_fatal (file_name);
 699 }
 700
 701 void
 702 sys_wait_command (void)
 703 {
 704   int status;
 705
 706   if (global_pid < 0)
 707     return;
 708
 709   signal (SIGPIPE, pipe_handler);
 710   while (waitpid (global_pid, &status, 0) == -1)
 711     if (errno != EINTR)
 712       {
 713         global_pid = -1;
 714         waitpid_error (to_command_option);
 715         return;
 716       }
 717
 718   if (WIFEXITED (status))
 719     {
 720       if (!ignore_command_error_option && WEXITSTATUS (status))
 721         ERROR ((0, 0, _("%lu: Child returned status %d"),
 722                 (unsigned long) global_pid, WEXITSTATUS (status)));
 723     }
 724   else if (WIFSIGNALED (status))
 725     {
 726       WARN ((0, 0, _("%lu: Child terminated on signal %d"),
 727              (unsigned long) global_pid, WTERMSIG (status)));
 728     }
 729   else
 730     ERROR ((0, 0, _("%lu: Child terminated on unknown reason"),
 731             (unsigned long) global_pid));
 732
 733   global_pid = -1;
 734 }
 735
 736 int
 737 sys_exec_info_script (const char **archive_name, int volume_number)
 738 {
 739   pid_t pid;
 740   char *argv[4];
 741   char uintbuf[UINTMAX_STRSIZE_BOUND];
 742   int p[2];
 743   static RETSIGTYPE (*saved_handler) (int sig);
 744
 745   xpipe (p);
 746   saved_handler = signal (SIGPIPE, SIG_IGN);
 747
 748   pid = xfork ();
 749
 750   if (pid != 0)
 751     {
 752       /* Master */
 753
 754       int rc;
 755       int status;
 756       char *buf = NULL;
 757       size_t size = 0;
 758       FILE *fp;
 759
 760       xclose (p[PWRITE]);
 761       fp = fdopen (p[PREAD], "r");
 762       rc = getline (&buf, &size, fp);
 763       fclose (fp);
 764
 765       if (rc > 0 && buf[rc-1] == '\n')
 766         buf[--rc] = 0;
 767
 768       while (waitpid (pid, &status, 0) == -1)
 769         if (errno != EINTR)
 770           {
 771             signal (SIGPIPE, saved_handler);
 772             waitpid_error (info_script_option);
 773             return -1;
 774           }
 775
 776       signal (SIGPIPE, saved_handler);
 777
 778       if (WIFEXITED (status))
 779         {
 780           if (WEXITSTATUS (status) == 0 && rc > 0)
 781             *archive_name = buf;
 782           else
 783             free (buf);
 784           return WEXITSTATUS (status);
 785         }
 786
 787       free (buf);
 788       return -1;
 789     }
 790
 791   /* Child */
 792   setenv ("TAR_VERSION", PACKAGE_VERSION, 1);
 793   setenv ("TAR_ARCHIVE", *archive_name, 1);
 794   setenv ("TAR_VOLUME", STRINGIFY_BIGINT (volume_number, uintbuf), 1);
 795   setenv ("TAR_BLOCKING_FACTOR",
 796           STRINGIFY_BIGINT (blocking_factor, uintbuf), 1);
 797   setenv ("TAR_SUBCOMMAND", subcommand_string (subcommand_option), 1);
 798   setenv ("TAR_FORMAT",
 799           archive_format_string (current_format == DEFAULT_FORMAT ?
 800                                  archive_format : current_format), 1);
 801   setenv ("TAR_FD", STRINGIFY_BIGINT (p[PWRITE], uintbuf), 1);
 802
 803   xclose (p[PREAD]);
 804
 805   argv[0] = "/bin/sh";
 806   argv[1] = "-c";
 807   argv[2] = (char*) info_script_option;
 808   argv[3] = NULL;
 809
 810   execv (argv[0], argv);
 811
 812   exec_fatal (info_script_option);
 813 }
 814
 815 void
 816 sys_exec_checkpoint_script (const char *script_name,
 817                             const char *archive_name,
 818                             int checkpoint_number)
 819 {
 820   pid_t pid;
 821   char *argv[4];
 822   char uintbuf[UINTMAX_STRSIZE_BOUND];
 823
 824   pid = xfork ();
 825
 826   if (pid != 0)
 827     {
 828       /* Master */
 829
 830       int status;
 831
 832       while (waitpid (pid, &status, 0) == -1)
 833         if (errno != EINTR)
 834           {
 835             waitpid_error (script_name);
 836             break;
 837           }
 838
 839       return;
 840     }
 841
 842   /* Child */
 843   setenv ("TAR_VERSION", PACKAGE_VERSION, 1);
 844   setenv ("TAR_ARCHIVE", archive_name, 1);
 845   setenv ("TAR_CHECKPOINT", STRINGIFY_BIGINT (checkpoint_number, uintbuf), 1);
 846   setenv ("TAR_BLOCKING_FACTOR",
 847           STRINGIFY_BIGINT (blocking_factor, uintbuf), 1);
 848   setenv ("TAR_SUBCOMMAND", subcommand_string (subcommand_option), 1);
 849   setenv ("TAR_FORMAT",
 850           archive_format_string (current_format == DEFAULT_FORMAT ?
 851                                  archive_format : current_format), 1);
 852   argv[0] = "/bin/sh";
 853   argv[1] = "-c";
 854   argv[2] = (char*) script_name;
 855   argv[3] = NULL;
 856
 857   execv (argv[0], argv);
 858
 859   exec_fatal (script_name);
 860 }
 861
 862 #endif /* not MSDOS */