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

   1 /* System-dependent calls for tar.
   2
   3    Copyright 2003-2008, 2010, 2013 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify it
   6    under the terms of the GNU General Public License as published by the
   7    Free Software Foundation; either version 3, or (at your option) any later
   8    version.
   9
  10    This program is distributed in the hope that it will be useful, but
  11    WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  13    Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License along
  16    with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <system.h>
  19
  20 #include "common.h"
  21 #include <priv-set.h>
  22 #include <rmt.h>
  23 #include <signal.h>
  24
  25 #if MSDOS
  26
  27 bool
  28 sys_get_archive_stat (void)
  29 {
  30   return 0;
  31 }
  32
  33 bool
  34 sys_file_is_archive (struct tar_stat_info *p)
  35 {
  36   return false;
  37 }
  38
  39 void
  40 sys_save_archive_dev_ino (void)
  41 {
  42 }
  43
  44 void
  45 sys_detect_dev_null_output (void)
  46 {
  47   static char const dev_null[] = "nul";
  48
  49   dev_null_output = (strcmp (archive_name_array[0], dev_null) == 0
  50                      || (! _isrmt (archive)));
  51 }
  52
  53 void
  54 sys_wait_for_child (pid_t child_pid, bool eof)
  55 {
  56 }
  57
  58 void
  59 sys_spawn_shell (void)
  60 {
  61   spawnl (P_WAIT, getenv ("COMSPEC"), "-", 0);
  62 }
  63
  64 /* stat() in djgpp's C library gives a constant number of 42 as the
  65    uid and gid of a file.  So, comparing an FTP'ed archive just after
  66    unpack would fail on MSDOS.  */
  67
  68 bool
  69 sys_compare_uid (struct stat *a, struct stat *b)
  70 {
  71   return true;
  72 }
  73
  74 bool
  75 sys_compare_gid (struct stat *a, struct stat *b)
  76 {
  77   return true;
  78 }
  79
  80 void
  81 sys_compare_links (struct stat *link_data, struct stat *stat_data)
  82 {
  83   return true;
  84 }
  85
  86 int
  87 sys_truncate (int fd)
  88 {
  89   return write (fd, "", 0);
  90 }
  91
  92 size_t
  93 sys_write_archive_buffer (void)
  94 {
  95   return full_write (archive, record_start->buffer, record_size);
  96 }
  97
  98 /* Set ARCHIVE for writing, then compressing an archive.  */
  99 void
 100 sys_child_open_for_compress (void)
 101 {
 102   FATAL_ERROR ((0, 0, _("Cannot use compressed or remote archives")));
 103 }
 104
 105 /* Set ARCHIVE for uncompressing, then reading an archive.  */
 106 void
 107 sys_child_open_for_uncompress (void)
 108 {
 109   FATAL_ERROR ((0, 0, _("Cannot use compressed or remote archives")));
 110 }
 111
 112 #else
 113
 114 extern union block *record_start; /* FIXME */
 115
 116 static struct stat archive_stat; /* stat block for archive file */
 117
 118 bool
 119 sys_get_archive_stat (void)
 120 {
 121   return fstat (archive, &archive_stat) == 0;
 122 }
 123
 124 bool
 125 sys_file_is_archive (struct tar_stat_info *p)
 126 {
 127   return (ar_dev && p->stat.st_dev == ar_dev && p->stat.st_ino == ar_ino);
 128 }
 129
 130 /* Save archive file inode and device numbers */
 131 void
 132 sys_save_archive_dev_ino (void)
 133 {
 134   if (!_isrmt (archive) && S_ISREG (archive_stat.st_mode))
 135     {
 136       ar_dev = archive_stat.st_dev;
 137       ar_ino = archive_stat.st_ino;
 138     }
 139   else
 140     ar_dev = 0;
 141 }
 142
 143 /* Detect if outputting to "/dev/null".  */
 144 void
 145 sys_detect_dev_null_output (void)
 146 {
 147   static char const dev_null[] = "/dev/null";
 148   struct stat dev_null_stat;
 149
 150   dev_null_output = (strcmp (archive_name_array[0], dev_null) == 0
 151                      || (! _isrmt (archive)
 152                          && S_ISCHR (archive_stat.st_mode)
 153                          && stat (dev_null, &dev_null_stat) == 0
 154                          && archive_stat.st_dev == dev_null_stat.st_dev
 155                          && archive_stat.st_ino == dev_null_stat.st_ino));
 156 }
 157
 158 void
 159 sys_wait_for_child (pid_t child_pid, bool eof)
 160 {
 161   if (child_pid)
 162     {
 163       int wait_status;
 164
 165       while (waitpid (child_pid, &wait_status, 0) == -1)
 166         if (errno != EINTR)
 167           {
 168             waitpid_error (use_compress_program_option);
 169             break;
 170           }
 171
 172       if (WIFSIGNALED (wait_status))
 173         {
 174           int sig = WTERMSIG (wait_status);
 175           if (!(!eof && sig == SIGPIPE))
 176             FATAL_ERROR ((0, 0, _("Child died with signal %d"), sig));
 177         }
 178       else if (WEXITSTATUS (wait_status) != 0)
 179         FATAL_ERROR ((0, 0, _("Child returned status %d"),
 180                       WEXITSTATUS (wait_status)));
 181     }
 182 }
 183
 184 void
 185 sys_spawn_shell (void)
 186 {
 187   pid_t child;
 188   const char *shell = getenv ("SHELL");
 189   if (! shell)
 190     shell = "/bin/sh";
 191   child = xfork ();
 192   if (child == 0)
 193     {
 194       priv_set_restore_linkdir ();
 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 static void wait_for_grandchild (pid_t pid) __attribute__ ((__noreturn__));
 287
 288 /* Propagate any failure of the grandchild back to the parent.  */
 289 static 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   set_program_name (_("tar (child)"));
 334   signal (SIGPIPE, SIG_DFL);
 335
 336   xdup2 (parent_pipe[PREAD], STDIN_FILENO);
 337   xclose (parent_pipe[PWRITE]);
 338
 339   /* Check if we need a grandchild tar.  This happens only if either:
 340      a) the file is to be accessed by rmt: compressor doesn't know how;
 341      b) the file is not a plain file.  */
 342
 343   if (!_remdev (archive_name_array[0])
 344       && is_regular_file (archive_name_array[0]))
 345     {
 346       if (backup_option)
 347         maybe_backup_file (archive_name_array[0], 1);
 348
 349       /* We don't need a grandchild tar.  Open the archive and launch the
 350          compressor.  */
 351       if (strcmp (archive_name_array[0], "-"))
 352         {
 353           archive = creat (archive_name_array[0], MODE_RW);
 354           if (archive < 0)
 355             {
 356               int saved_errno = errno;
 357
 358               if (backup_option)
 359                 undo_last_backup ();
 360               errno = saved_errno;
 361               open_fatal (archive_name_array[0]);
 362             }
 363           xdup2 (archive, STDOUT_FILENO);
 364         }
 365       priv_set_restore_linkdir ();
 366       execlp (use_compress_program_option, use_compress_program_option, NULL);
 367       exec_fatal (use_compress_program_option);
 368     }
 369
 370   /* We do need a grandchild tar.  */
 371
 372   xpipe (child_pipe);
 373   grandchild_pid = xfork ();
 374
 375   if (grandchild_pid == 0)
 376     {
 377       /* The newborn grandchild tar is here!  Launch the compressor.  */
 378
 379       set_program_name (_("tar (grandchild)"));
 380
 381       xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
 382       xclose (child_pipe[PREAD]);
 383       priv_set_restore_linkdir ();
 384       execlp (use_compress_program_option, use_compress_program_option,
 385               (char *) 0);
 386       exec_fatal (use_compress_program_option);
 387     }
 388
 389   /* The child tar is still here!  */
 390
 391   /* Prepare for reblocking the data from the compressor into the archive.  */
 392
 393   xdup2 (child_pipe[PREAD], STDIN_FILENO);
 394   xclose (child_pipe[PWRITE]);
 395
 396   if (strcmp (archive_name_array[0], "-") == 0)
 397     archive = STDOUT_FILENO;
 398   else
 399     {
 400       archive = rmtcreat (archive_name_array[0], MODE_RW, rsh_command_option);
 401       if (archive < 0)
 402         open_fatal (archive_name_array[0]);
 403     }
 404
 405   /* Let's read out of the stdin pipe and write an archive.  */
 406
 407   while (1)
 408     {
 409       size_t status = 0;
 410       char *cursor;
 411       size_t length;
 412
 413       /* Assemble a record.  */
 414
 415       for (length = 0, cursor = record_start->buffer;
 416            length < record_size;
 417            length += status, cursor += status)
 418         {
 419           size_t size = record_size - length;
 420
 421           status = safe_read (STDIN_FILENO, cursor, size);
 422           if (status == SAFE_READ_ERROR)
 423             read_fatal (use_compress_program_option);
 424           if (status == 0)
 425             break;
 426         }
 427
 428       /* Copy the record.  */
 429
 430       if (status == 0)
 431         {
 432           /* We hit the end of the file.  Write last record at
 433              full length, as the only role of the grandchild is
 434              doing proper reblocking.  */
 435
 436           if (length > 0)
 437             {
 438               memset (record_start->buffer + length, 0, record_size - length);
 439               status = sys_write_archive_buffer ();
 440               if (status != record_size)
 441                 archive_write_error (status);
 442             }
 443
 444           /* There is nothing else to read, break out.  */
 445           break;
 446         }
 447
 448       status = sys_write_archive_buffer ();
 449       if (status != record_size)
 450         archive_write_error (status);
 451     }
 452
 453   wait_for_grandchild (grandchild_pid);
 454 }
 455
 456 static void
 457 run_decompress_program (void)
 458 {
 459   int i;
 460   const char *p, *prog = NULL;
 461
 462   for (p = first_decompress_program (&i); p; p = next_decompress_program (&i))
 463     {
 464       if (prog)
 465         {
 466           WARNOPT (WARN_DECOMPRESS_PROGRAM,
 467                    (0, errno, _("cannot run %s"), prog));
 468           WARNOPT (WARN_DECOMPRESS_PROGRAM,
 469                    (0, 0, _("trying %s"), p));
 470         }
 471       prog = p;
 472       execlp (p, p, "-d", NULL);
 473     }
 474   if (!prog)
 475     FATAL_ERROR ((0, 0, _("unable to run decompression program")));
 476   exec_fatal (prog);
 477 }
 478
 479 /* Set ARCHIVE for uncompressing, then reading an archive.  */
 480 pid_t
 481 sys_child_open_for_uncompress (void)
 482 {
 483   int parent_pipe[2];
 484   int child_pipe[2];
 485   pid_t grandchild_pid;
 486   pid_t child_pid;
 487
 488   xpipe (parent_pipe);
 489   child_pid = xfork ();
 490
 491   if (child_pid > 0)
 492     {
 493       /* The parent tar is still here!  Just clean up.  */
 494
 495       archive = parent_pipe[PREAD];
 496       xclose (parent_pipe[PWRITE]);
 497       return child_pid;
 498     }
 499
 500   /* The newborn child tar is here!  */
 501
 502   set_program_name (_("tar (child)"));
 503   signal (SIGPIPE, SIG_DFL);
 504
 505   xdup2 (parent_pipe[PWRITE], STDOUT_FILENO);
 506   xclose (parent_pipe[PREAD]);
 507
 508   /* Check if we need a grandchild tar.  This happens only if either:
 509      a) we're reading stdin: to force unblocking;
 510      b) the file is to be accessed by rmt: compressor doesn't know how;
 511      c) the file is not a plain file.  */
 512
 513   if (strcmp (archive_name_array[0], "-") != 0
 514       && !_remdev (archive_name_array[0])
 515       && is_regular_file (archive_name_array[0]))
 516     {
 517       /* We don't need a grandchild tar.  Open the archive and lauch the
 518          uncompressor.  */
 519
 520       archive = open (archive_name_array[0], O_RDONLY | O_BINARY, MODE_RW);
 521       if (archive < 0)
 522         open_fatal (archive_name_array[0]);
 523       xdup2 (archive, STDIN_FILENO);
 524       priv_set_restore_linkdir ();
 525       run_decompress_program ();
 526     }
 527
 528   /* We do need a grandchild tar.  */
 529
 530   xpipe (child_pipe);
 531   grandchild_pid = xfork ();
 532
 533   if (grandchild_pid == 0)
 534     {
 535       /* The newborn grandchild tar is here!  Launch the uncompressor.  */
 536
 537       set_program_name (_("tar (grandchild)"));
 538
 539       xdup2 (child_pipe[PREAD], STDIN_FILENO);
 540       xclose (child_pipe[PWRITE]);
 541       priv_set_restore_linkdir ();
 542       run_decompress_program ();
 543     }
 544
 545   /* The child tar is still here!  */
 546
 547   /* Prepare for unblocking the data from the archive into the
 548      uncompressor.  */
 549
 550   xdup2 (child_pipe[PWRITE], STDOUT_FILENO);
 551   xclose (child_pipe[PREAD]);
 552
 553   if (strcmp (archive_name_array[0], "-") == 0)
 554     archive = STDIN_FILENO;
 555   else
 556     archive = rmtopen (archive_name_array[0], O_RDONLY | O_BINARY,
 557                        MODE_RW, rsh_command_option);
 558   if (archive < 0)
 559     open_fatal (archive_name_array[0]);
 560
 561   /* Let's read the archive and pipe it into stdout.  */
 562
 563   while (1)
 564     {
 565       char *cursor;
 566       size_t maximum;
 567       size_t count;
 568       size_t status;
 569
 570       clear_read_error_count ();
 571
 572     error_loop:
 573       status = rmtread (archive, record_start->buffer, record_size);
 574       if (status == SAFE_READ_ERROR)
 575         {
 576           archive_read_error ();
 577           goto error_loop;
 578         }
 579       if (status == 0)
 580         break;
 581       cursor = record_start->buffer;
 582       maximum = status;
 583       while (maximum)
 584         {
 585           count = maximum < BLOCKSIZE ? maximum : BLOCKSIZE;
 586           if (full_write (STDOUT_FILENO, cursor, count) != count)
 587             write_error (use_compress_program_option);
 588           cursor += count;
 589           maximum -= count;
 590         }
 591     }
 592
 593   xclose (STDOUT_FILENO);
 594
 595   wait_for_grandchild (grandchild_pid);
 596 }
 597
 598 \f
 599
 600 static void
 601 dec_to_env (char const *envar, uintmax_t num)
 602 {
 603   char buf[UINTMAX_STRSIZE_BOUND];
 604   char *numstr;
 605
 606   numstr = STRINGIFY_BIGINT (num, buf);
 607   if (setenv (envar, numstr, 1) != 0)
 608     xalloc_die ();
 609 }
 610
 611 static void
 612 time_to_env (char const *envar, struct timespec t)
 613 {
 614   char buf[TIMESPEC_STRSIZE_BOUND];
 615   if (setenv (envar, code_timespec (t, buf), 1) != 0)
 616     xalloc_die ();
 617 }
 618
 619 static void
 620 oct_to_env (char const *envar, unsigned long num)
 621 {
 622   char buf[1+1+(sizeof(unsigned long)*CHAR_BIT+2)/3];
 623
 624   snprintf (buf, sizeof buf, "0%lo", num);
 625   if (setenv (envar, buf, 1) != 0)
 626     xalloc_die ();
 627 }
 628
 629 static void
 630 str_to_env (char const *envar, char const *str)
 631 {
 632   if (str)
 633     {
 634       if (setenv (envar, str, 1) != 0)
 635         xalloc_die ();
 636     }
 637   else
 638     unsetenv (envar);
 639 }
 640
 641 static void
 642 chr_to_env (char const *envar, char c)
 643 {
 644   char buf[2];
 645   buf[0] = c;
 646   buf[1] = 0;
 647   if (setenv (envar, buf, 1) != 0)
 648     xalloc_die ();
 649 }
 650
 651 static void
 652 stat_to_env (char *name, char type, struct tar_stat_info *st)
 653 {
 654   str_to_env ("TAR_VERSION", PACKAGE_VERSION);
 655   str_to_env ("TAR_ARCHIVE", *archive_name_cursor);
 656   dec_to_env ("TAR_VOLUME", archive_name_cursor - archive_name_array + 1);
 657   dec_to_env ("TAR_BLOCKING_FACTOR", blocking_factor);
 658   str_to_env ("TAR_FORMAT",
 659               archive_format_string (current_format == DEFAULT_FORMAT ?
 660                                      archive_format : current_format));
 661   chr_to_env ("TAR_FILETYPE", type);
 662   oct_to_env ("TAR_MODE", st->stat.st_mode);
 663   str_to_env ("TAR_FILENAME", name);
 664   str_to_env ("TAR_REALNAME", st->file_name);
 665   str_to_env ("TAR_UNAME", st->uname);
 666   str_to_env ("TAR_GNAME", st->gname);
 667   time_to_env ("TAR_ATIME", st->atime);
 668   time_to_env ("TAR_MTIME", st->mtime);
 669   time_to_env ("TAR_CTIME", st->ctime);
 670   dec_to_env ("TAR_SIZE", st->stat.st_size);
 671   dec_to_env ("TAR_UID", st->stat.st_uid);
 672   dec_to_env ("TAR_GID", st->stat.st_gid);
 673
 674   switch (type)
 675     {
 676     case 'b':
 677     case 'c':
 678       dec_to_env ("TAR_MINOR", minor (st->stat.st_rdev));
 679       dec_to_env ("TAR_MAJOR", major (st->stat.st_rdev));
 680       unsetenv ("TAR_LINKNAME");
 681       break;
 682
 683     case 'l':
 684     case 'h':
 685       unsetenv ("TAR_MINOR");
 686       unsetenv ("TAR_MAJOR");
 687       str_to_env ("TAR_LINKNAME", st->link_name);
 688       break;
 689
 690     default:
 691       unsetenv ("TAR_MINOR");
 692       unsetenv ("TAR_MAJOR");
 693       unsetenv ("TAR_LINKNAME");
 694       break;
 695     }
 696 }
 697
 698 static pid_t global_pid;
 699 static RETSIGTYPE (*pipe_handler) (int sig);
 700
 701 int
 702 sys_exec_command (char *file_name, int typechar, struct tar_stat_info *st)
 703 {
 704   int p[2];
 705   char *argv[4];
 706
 707   xpipe (p);
 708   pipe_handler = signal (SIGPIPE, SIG_IGN);
 709   global_pid = xfork ();
 710
 711   if (global_pid != 0)
 712     {
 713       xclose (p[PREAD]);
 714       return p[PWRITE];
 715     }
 716
 717   /* Child */
 718   xdup2 (p[PREAD], STDIN_FILENO);
 719   xclose (p[PWRITE]);
 720
 721   stat_to_env (file_name, typechar, st);
 722
 723   argv[0] = (char *) "/bin/sh";
 724   argv[1] = (char *) "-c";
 725   argv[2] = to_command_option;
 726   argv[3] = NULL;
 727
 728   priv_set_restore_linkdir ();
 729   execv ("/bin/sh", argv);
 730
 731   exec_fatal (file_name);
 732 }
 733
 734 void
 735 sys_wait_command (void)
 736 {
 737   int status;
 738
 739   if (global_pid < 0)
 740     return;
 741
 742   signal (SIGPIPE, pipe_handler);
 743   while (waitpid (global_pid, &status, 0) == -1)
 744     if (errno != EINTR)
 745       {
 746         global_pid = -1;
 747         waitpid_error (to_command_option);
 748         return;
 749       }
 750
 751   if (WIFEXITED (status))
 752     {
 753       if (!ignore_command_error_option && WEXITSTATUS (status))
 754         ERROR ((0, 0, _("%lu: Child returned status %d"),
 755                 (unsigned long) global_pid, WEXITSTATUS (status)));
 756     }
 757   else if (WIFSIGNALED (status))
 758     {
 759       WARN ((0, 0, _("%lu: Child terminated on signal %d"),
 760              (unsigned long) global_pid, WTERMSIG (status)));
 761     }
 762   else
 763     ERROR ((0, 0, _("%lu: Child terminated on unknown reason"),
 764             (unsigned long) global_pid));
 765
 766   global_pid = -1;
 767 }
 768
 769 int
 770 sys_exec_info_script (const char **archive_name, int volume_number)
 771 {
 772   pid_t pid;
 773   char *argv[4];
 774   char uintbuf[UINTMAX_STRSIZE_BOUND];
 775   int p[2];
 776   static RETSIGTYPE (*saved_handler) (int sig);
 777
 778   xpipe (p);
 779   saved_handler = signal (SIGPIPE, SIG_IGN);
 780
 781   pid = xfork ();
 782
 783   if (pid != 0)
 784     {
 785       /* Master */
 786
 787       int rc;
 788       int status;
 789       char *buf = NULL;
 790       size_t size = 0;
 791       FILE *fp;
 792
 793       xclose (p[PWRITE]);
 794       fp = fdopen (p[PREAD], "r");
 795       rc = getline (&buf, &size, fp);
 796       fclose (fp);
 797
 798       if (rc > 0 && buf[rc-1] == '\n')
 799         buf[--rc] = 0;
 800
 801       while (waitpid (pid, &status, 0) == -1)
 802         if (errno != EINTR)
 803           {
 804             signal (SIGPIPE, saved_handler);
 805             waitpid_error (info_script_option);
 806             return -1;
 807           }
 808
 809       signal (SIGPIPE, saved_handler);
 810
 811       if (WIFEXITED (status))
 812         {
 813           if (WEXITSTATUS (status) == 0 && rc > 0)
 814             *archive_name = buf;
 815           else
 816             free (buf);
 817           return WEXITSTATUS (status);
 818         }
 819
 820       free (buf);
 821       return -1;
 822     }
 823
 824   /* Child */
 825   setenv ("TAR_VERSION", PACKAGE_VERSION, 1);
 826   setenv ("TAR_ARCHIVE", *archive_name, 1);
 827   setenv ("TAR_VOLUME", STRINGIFY_BIGINT (volume_number, uintbuf), 1);
 828   setenv ("TAR_BLOCKING_FACTOR",
 829           STRINGIFY_BIGINT (blocking_factor, uintbuf), 1);
 830   setenv ("TAR_SUBCOMMAND", subcommand_string (subcommand_option), 1);
 831   setenv ("TAR_FORMAT",
 832           archive_format_string (current_format == DEFAULT_FORMAT ?
 833                                  archive_format : current_format), 1);
 834   setenv ("TAR_FD", STRINGIFY_BIGINT (p[PWRITE], uintbuf), 1);
 835
 836   xclose (p[PREAD]);
 837
 838   argv[0] = (char *) "/bin/sh";
 839   argv[1] = (char *) "-c";
 840   argv[2] = (char *) info_script_option;
 841   argv[3] = NULL;
 842
 843   priv_set_restore_linkdir ();
 844   execv (argv[0], argv);
 845
 846   exec_fatal (info_script_option);
 847 }
 848
 849 void
 850 sys_exec_checkpoint_script (const char *script_name,
 851                             const char *archive_name,
 852                             int checkpoint_number)
 853 {
 854   pid_t pid;
 855   char *argv[4];
 856   char uintbuf[UINTMAX_STRSIZE_BOUND];
 857
 858   pid = xfork ();
 859
 860   if (pid != 0)
 861     {
 862       /* Master */
 863
 864       int status;
 865
 866       while (waitpid (pid, &status, 0) == -1)
 867         if (errno != EINTR)
 868           {
 869             waitpid_error (script_name);
 870             break;
 871           }
 872
 873       return;
 874     }
 875
 876   /* Child */
 877   setenv ("TAR_VERSION", PACKAGE_VERSION, 1);
 878   setenv ("TAR_ARCHIVE", archive_name, 1);
 879   setenv ("TAR_CHECKPOINT", STRINGIFY_BIGINT (checkpoint_number, uintbuf), 1);
 880   setenv ("TAR_BLOCKING_FACTOR",
 881           STRINGIFY_BIGINT (blocking_factor, uintbuf), 1);
 882   setenv ("TAR_SUBCOMMAND", subcommand_string (subcommand_option), 1);
 883   setenv ("TAR_FORMAT",
 884           archive_format_string (current_format == DEFAULT_FORMAT ?
 885                                  archive_format : current_format), 1);
 886   argv[0] = (char *) "/bin/sh";
 887   argv[1] = (char *) "-c";
 888   argv[2] = (char *) script_name;
 889   argv[3] = NULL;
 890
 891   priv_set_restore_linkdir ();
 892   execv (argv[0], argv);
 893
 894   exec_fatal (script_name);
 895 }
 896
 897 #endif /* not MSDOS */