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