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

   1 /* Miscellaneous functions, not really specific to GNU tar.
   2
   3    Copyright (C) 1988, 1992, 1994, 1995, 1996, 1997, 1999, 2000, 2001,
   4    2003, 2004 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 2, or (at your option) any later
   9    version.
  10
  11    This program is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
  14    Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License along
  17    with this program; if not, write to the Free Software Foundation, Inc.,
  18    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #include "system.h"
  21 #include "rmt.h"
  22 #include "common.h"
  23 #include <quotearg.h>
  24 #include <save-cwd.h>
  25
  26 static void call_arg_fatal (char const *, char const *)
  27      __attribute__ ((noreturn));
  28 \f
  29 /* Handling strings.  */
  30
  31 /* Assign STRING to a copy of VALUE if not zero, or to zero.  If
  32    STRING was nonzero, it is freed first.  */
  33 void
  34 assign_string (char **string, const char *value)
  35 {
  36   if (*string)
  37     free (*string);
  38   *string = value ? xstrdup (value) : 0;
  39 }
  40
  41 /* Allocate a copy of the string quoted as in C, and returns that.  If
  42    the string does not have to be quoted, it returns a null pointer.
  43    The allocated copy should normally be freed with free() after the
  44    caller is done with it.
  45
  46    This is used in one context only: generating the directory file in
  47    incremental dumps.  The quoted string is not intended for human
  48    consumption; it is intended only for unquote_string.  The quoting
  49    is locale-independent, so that users needn't worry about locale
  50    when reading directory files.  This means that we can't use
  51    quotearg, as quotearg is locale-dependent and is meant for human
  52    consumption.  */
  53 char *
  54 quote_copy_string (const char *string)
  55 {
  56   const char *source = string;
  57   char *destination = 0;
  58   char *buffer = 0;
  59   int copying = 0;
  60
  61   while (*source)
  62     {
  63       int character = *source++;
  64
  65       switch (character)
  66         {
  67         case '\n': case '\\':
  68           if (!copying)
  69             {
  70               size_t length = (source - string) - 1;
  71
  72               copying = 1;
  73               buffer = xmalloc (length + 2 + 2 * strlen (source) + 1);
  74               memcpy (buffer, string, length);
  75               destination = buffer + length;
  76             }
  77           *destination++ = '\\';
  78           *destination++ = character == '\\' ? '\\' : 'n';
  79           break;
  80
  81         default:
  82           if (copying)
  83             *destination++ = character;
  84           break;
  85         }
  86     }
  87   if (copying)
  88     {
  89       *destination = '\0';
  90       return buffer;
  91     }
  92   return 0;
  93 }
  94
  95 /* Takes a quoted C string (like those produced by quote_copy_string)
  96    and turns it back into the un-quoted original.  This is done in
  97    place.  Returns 0 only if the string was not properly quoted, but
  98    completes the unquoting anyway.
  99
 100    This is used for reading the saved directory file in incremental
 101    dumps.  It is used for decoding old `N' records (demangling names).
 102    But also, it is used for decoding file arguments, would they come
 103    from the shell or a -T file, and for decoding the --exclude
 104    argument.  */
 105 int
 106 unquote_string (char *string)
 107 {
 108   int result = 1;
 109   char *source = string;
 110   char *destination = string;
 111
 112   /* Escape sequences other than \\ and \n are no longer generated by
 113      quote_copy_string, but accept them for backwards compatibility,
 114      and also because unquote_string is used for purposes other than
 115      parsing the output of quote_copy_string.  */
 116
 117   while (*source)
 118     if (*source == '\\')
 119       switch (*++source)
 120         {
 121         case '\\':
 122           *destination++ = '\\';
 123           source++;
 124           break;
 125
 126         case 'n':
 127           *destination++ = '\n';
 128           source++;
 129           break;
 130
 131         case 't':
 132           *destination++ = '\t';
 133           source++;
 134           break;
 135
 136         case 'f':
 137           *destination++ = '\f';
 138           source++;
 139           break;
 140
 141         case 'b':
 142           *destination++ = '\b';
 143           source++;
 144           break;
 145
 146         case 'r':
 147           *destination++ = '\r';
 148           source++;
 149           break;
 150
 151         case '?':
 152           *destination++ = 0177;
 153           source++;
 154           break;
 155
 156         case '0':
 157         case '1':
 158         case '2':
 159         case '3':
 160         case '4':
 161         case '5':
 162         case '6':
 163         case '7':
 164           {
 165             int value = *source++ - '0';
 166
 167             if (*source < '0' || *source > '7')
 168               {
 169                 *destination++ = value;
 170                 break;
 171               }
 172             value = value * 8 + *source++ - '0';
 173             if (*source < '0' || *source > '7')
 174               {
 175                 *destination++ = value;
 176                 break;
 177               }
 178             value = value * 8 + *source++ - '0';
 179             *destination++ = value;
 180             break;
 181           }
 182
 183         default:
 184           result = 0;
 185           *destination++ = '\\';
 186           if (*source)
 187             *destination++ = *source++;
 188           break;
 189         }
 190     else if (source != destination)
 191       *destination++ = *source++;
 192     else
 193       source++, destination++;
 194
 195   if (source != destination)
 196     *destination = '\0';
 197   return result;
 198 }
 199 \f
 200 /* File handling.  */
 201
 202 /* Saved names in case backup needs to be undone.  */
 203 static char *before_backup_name;
 204 static char *after_backup_name;
 205
 206 /* Return 1 if FILE_NAME is obviously "." or "/".  */
 207 static bool
 208 must_be_dot_or_slash (char const *file_name)
 209 {
 210   file_name += FILE_SYSTEM_PREFIX_LEN (file_name);
 211
 212   if (ISSLASH (file_name[0]))
 213     {
 214       for (;;)
 215         if (ISSLASH (file_name[1]))
 216           file_name++;
 217         else if (file_name[1] == '.'
 218                  && ISSLASH (file_name[2 + (file_name[2] == '.')]))
 219           file_name += 2 + (file_name[2] == '.');
 220         else
 221           return ! file_name[1];
 222     }
 223   else
 224     {
 225       while (file_name[0] == '.' && ISSLASH (file_name[1]))
 226         {
 227           file_name += 2;
 228           while (ISSLASH (*file_name))
 229             file_name++;
 230         }
 231
 232       return ! file_name[0] || (file_name[0] == '.' && ! file_name[1]);
 233     }
 234 }
 235
 236 /* Some implementations of rmdir let you remove '.' or '/'.
 237    Report an error with errno set to zero for obvious cases of this;
 238    otherwise call rmdir.  */
 239 static int
 240 safer_rmdir (const char *file_name)
 241 {
 242   if (must_be_dot_or_slash (file_name))
 243     {
 244       errno = 0;
 245       return -1;
 246     }
 247
 248   return rmdir (file_name);
 249 }
 250
 251 /* Remove FILE_NAME, returning 1 on success.  If FILE_NAME is a directory,
 252    then if OPTION is RECURSIVE_REMOVE_OPTION is set remove FILE_NAME
 253    recursively; otherwise, remove it only if it is empty.  If FILE_NAME is
 254    a directory that cannot be removed (e.g., because it is nonempty)
 255    and if OPTION is WANT_DIRECTORY_REMOVE_OPTION, then return -1.
 256    Return 0 on error, with errno set; if FILE_NAME is obviously the working
 257    directory return zero with errno set to zero.  */
 258 int
 259 remove_any_file (const char *file_name, enum remove_option option)
 260 {
 261   /* Try unlink first if we are not root, as this saves us a system
 262      call in the common case where we're removing a non-directory.  */
 263   if (! we_are_root)
 264     {
 265       if (unlink (file_name) == 0)
 266         return 1;
 267
 268       /* POSIX 1003.1-2001 requires EPERM when attempting to unlink a
 269          directory without appropriate privileges, but many Linux
 270          kernels return the more-sensible EISDIR.  */
 271       if (errno != EPERM && errno != EISDIR)
 272         return 0;
 273     }
 274
 275   if (safer_rmdir (file_name) == 0)
 276     return 1;
 277
 278   switch (errno)
 279     {
 280     case ENOTDIR:
 281       return we_are_root && unlink (file_name) == 0;
 282
 283     case 0:
 284     case EEXIST:
 285 #if defined ENOTEMPTY && ENOTEMPTY != EEXIST
 286     case ENOTEMPTY:
 287 #endif
 288       switch (option)
 289         {
 290         case ORDINARY_REMOVE_OPTION:
 291           break;
 292
 293         case WANT_DIRECTORY_REMOVE_OPTION:
 294           return -1;
 295
 296         case RECURSIVE_REMOVE_OPTION:
 297           {
 298             char *directory = savedir (file_name);
 299             char const *entry;
 300             size_t entrylen;
 301
 302             if (! directory)
 303               return 0;
 304
 305             for (entry = directory;
 306                  (entrylen = strlen (entry)) != 0;
 307                  entry += entrylen + 1)
 308               {
 309                 char *file_name_buffer = new_name (file_name, entry);
 310                 int r = remove_any_file (file_name_buffer, 1);
 311                 int e = errno;
 312                 free (file_name_buffer);
 313
 314                 if (! r)
 315                   {
 316                     free (directory);
 317                     errno = e;
 318                     return 0;
 319                   }
 320               }
 321
 322             free (directory);
 323             return safer_rmdir (file_name) == 0;
 324           }
 325         }
 326       break;
 327     }
 328
 329   return 0;
 330 }
 331
 332 /* Check if FILE_NAME already exists and make a backup of it right now.
 333    Return success (nonzero) only if the backup is either unneeded, or
 334    successful.  For now, directories are considered to never need
 335    backup.  If THIS_IS_THE_ARCHIVE is nonzero, this is the archive and
 336    so, we do not have to backup block or character devices, nor remote
 337    entities.  */
 338 bool
 339 maybe_backup_file (const char *file_name, int this_is_the_archive)
 340 {
 341   struct stat file_stat;
 342
 343   /* Check if we really need to backup the file.  */
 344
 345   if (this_is_the_archive && _remdev (file_name))
 346     return true;
 347
 348   if (stat (file_name, &file_stat))
 349     {
 350       if (errno == ENOENT)
 351         return true;
 352
 353       stat_error (file_name);
 354       return false;
 355     }
 356
 357   if (S_ISDIR (file_stat.st_mode))
 358     return true;
 359
 360   if (this_is_the_archive
 361       && (S_ISBLK (file_stat.st_mode) || S_ISCHR (file_stat.st_mode)))
 362     return true;
 363
 364   assign_string (&before_backup_name, file_name);
 365
 366   /* A run situation may exist between Emacs or other GNU programs trying to
 367      make a backup for the same file simultaneously.  If theoretically
 368      possible, real problems are unlikely.  Doing any better would require a
 369      convention, GNU-wide, for all programs doing backups.  */
 370
 371   assign_string (&after_backup_name, 0);
 372   after_backup_name = find_backup_file_name (file_name, backup_type);
 373   if (! after_backup_name)
 374     xalloc_die ();
 375
 376   if (rename (before_backup_name, after_backup_name) == 0)
 377     {
 378       if (verbose_option)
 379         fprintf (stdlis, _("Renaming %s to %s\n"),
 380                  quote_n (0, before_backup_name),
 381                  quote_n (1, after_backup_name));
 382       return true;
 383     }
 384   else
 385     {
 386       /* The backup operation failed.  */
 387       int e = errno;
 388       ERROR ((0, e, _("%s: Cannot rename to %s"),
 389               quotearg_colon (before_backup_name),
 390               quote_n (1, after_backup_name)));
 391       assign_string (&after_backup_name, 0);
 392       return false;
 393     }
 394 }
 395
 396 /* Try to restore the recently backed up file to its original name.
 397    This is usually only needed after a failed extraction.  */
 398 void
 399 undo_last_backup (void)
 400 {
 401   if (after_backup_name)
 402     {
 403       if (rename (after_backup_name, before_backup_name) != 0)
 404         {
 405           int e = errno;
 406           ERROR ((0, e, _("%s: Cannot rename to %s"),
 407                   quotearg_colon (after_backup_name),
 408                   quote_n (1, before_backup_name)));
 409         }
 410       if (verbose_option)
 411         fprintf (stdlis, _("Renaming %s back to %s\n"),
 412                  quote_n (0, after_backup_name),
 413                  quote_n (1, before_backup_name));
 414       assign_string (&after_backup_name, 0);
 415     }
 416 }
 417
 418 /* Depending on DEREF, apply either stat or lstat to (NAME, BUF).  */
 419 int
 420 deref_stat (bool deref, char const *name, struct stat *buf)
 421 {
 422   return deref ? stat (name, buf) : lstat (name, buf);
 423 }
 424
 425 /* A description of a working directory.  */
 426 struct wd
 427 {
 428   char const *name;
 429   int saved;
 430   struct saved_cwd saved_cwd;
 431 };
 432
 433 /* A vector of chdir targets.  wd[0] is the initial working directory.  */
 434 static struct wd *wd;
 435
 436 /* The number of working directories in the vector.  */
 437 static size_t wds;
 438
 439 /* The allocated size of the vector.  */
 440 static size_t wd_alloc;
 441
 442 /* DIR is the operand of a -C option; add it to vector of chdir targets,
 443    and return the index of its location.  */
 444 int
 445 chdir_arg (char const *dir)
 446 {
 447   if (wds == wd_alloc)
 448     {
 449       wd_alloc = 2 * (wd_alloc + 1);
 450       wd = xrealloc (wd, sizeof *wd * wd_alloc);
 451       if (! wds)
 452         {
 453           wd[wds].name = ".";
 454           wd[wds].saved = 0;
 455           wds++;
 456         }
 457     }
 458
 459   /* Optimize the common special case of the working directory,
 460      or the working directory as a prefix.  */
 461   if (dir[0])
 462     {
 463       while (dir[0] == '.' && ISSLASH (dir[1]))
 464         for (dir += 2;  ISSLASH (*dir);  dir++)
 465           continue;
 466       if (! dir[dir[0] == '.'])
 467         return wds - 1;
 468     }
 469
 470   wd[wds].name = dir;
 471   wd[wds].saved = 0;
 472   return wds++;
 473 }
 474
 475 /* Change to directory I.  If I is 0, change to the initial working
 476    directory; otherwise, I must be a value returned by chdir_arg.  */
 477 void
 478 chdir_do (int i)
 479 {
 480   static int previous;
 481
 482   if (previous != i)
 483     {
 484       struct wd *prev = &wd[previous];
 485       struct wd *curr = &wd[i];
 486
 487       if (! prev->saved)
 488         {
 489           prev->saved = 1;
 490           if (save_cwd (&prev->saved_cwd) != 0)
 491             FATAL_ERROR ((0, 0, _("Cannot save working directory")));
 492         }
 493
 494       if (curr->saved)
 495         {
 496           if (restore_cwd (&curr->saved_cwd))
 497             FATAL_ERROR ((0, 0, _("Cannot change working directory")));
 498         }
 499       else
 500         {
 501           if (i && ! ISSLASH (curr->name[0]))
 502             chdir_do (i - 1);
 503           if (chdir (curr->name) != 0)
 504             chdir_fatal (curr->name);
 505         }
 506
 507       previous = i;
 508     }
 509 }
 510 \f
 511 /* Decode MODE from its binary form in a stat structure, and encode it
 512    into a 9-byte string STRING, terminated with a NUL.  */
 513
 514 void
 515 decode_mode (mode_t mode, char *string)
 516 {
 517   *string++ = mode & S_IRUSR ? 'r' : '-';
 518   *string++ = mode & S_IWUSR ? 'w' : '-';
 519   *string++ = (mode & S_ISUID
 520                ? (mode & S_IXUSR ? 's' : 'S')
 521                : (mode & S_IXUSR ? 'x' : '-'));
 522   *string++ = mode & S_IRGRP ? 'r' : '-';
 523   *string++ = mode & S_IWGRP ? 'w' : '-';
 524   *string++ = (mode & S_ISGID
 525                ? (mode & S_IXGRP ? 's' : 'S')
 526                : (mode & S_IXGRP ? 'x' : '-'));
 527   *string++ = mode & S_IROTH ? 'r' : '-';
 528   *string++ = mode & S_IWOTH ? 'w' : '-';
 529   *string++ = (mode & S_ISVTX
 530                ? (mode & S_IXOTH ? 't' : 'T')
 531                : (mode & S_IXOTH ? 'x' : '-'));
 532   *string = '\0';
 533 }
 534
 535 /* Report an error associated with the system call CALL and the
 536    optional name NAME.  */
 537 static void
 538 call_arg_error (char const *call, char const *name)
 539 {
 540   int e = errno;
 541   ERROR ((0, e, _("%s: Cannot %s"), quotearg_colon (name), call));
 542 }
 543
 544 /* Report a fatal error associated with the system call CALL and
 545    the optional file name NAME.  */
 546 static void
 547 call_arg_fatal (char const *call, char const *name)
 548 {
 549   int e = errno;
 550   FATAL_ERROR ((0, e, _("%s: Cannot %s"), quotearg_colon (name),  call));
 551 }
 552
 553 /* Report a warning associated with the system call CALL and
 554    the optional file name NAME.  */
 555 static void
 556 call_arg_warn (char const *call, char const *name)
 557 {
 558   int e = errno;
 559   WARN ((0, e, _("%s: Warning: Cannot %s"), quotearg_colon (name), call));
 560 }
 561
 562 void
 563 chdir_fatal (char const *name)
 564 {
 565   call_arg_fatal ("chdir", name);
 566 }
 567
 568 void
 569 chmod_error_details (char const *name, mode_t mode)
 570 {
 571   int e = errno;
 572   char buf[10];
 573   decode_mode (mode, buf);
 574   ERROR ((0, e, _("%s: Cannot change mode to %s"),
 575           quotearg_colon (name), buf));
 576 }
 577
 578 void
 579 chown_error_details (char const *name, uid_t uid, gid_t gid)
 580 {
 581   int e = errno;
 582   ERROR ((0, e, _("%s: Cannot change ownership to uid %lu, gid %lu"),
 583           quotearg_colon (name), (unsigned long) uid, (unsigned long) gid));
 584 }
 585
 586 void
 587 close_error (char const *name)
 588 {
 589   call_arg_error ("close", name);
 590 }
 591
 592 void
 593 close_warn (char const *name)
 594 {
 595   call_arg_warn ("close", name);
 596 }
 597
 598 void
 599 close_diag (char const *name)
 600 {
 601   if (ignore_failed_read_option)
 602     close_warn (name);
 603   else
 604     close_error (name);
 605 }
 606
 607 void
 608 exec_fatal (char const *name)
 609 {
 610   call_arg_fatal ("exec", name);
 611 }
 612
 613 void
 614 link_error (char const *target, char const *source)
 615 {
 616   int e = errno;
 617   ERROR ((0, e, _("%s: Cannot hard link to %s"),
 618           quotearg_colon (source), quote_n (1, target)));
 619 }
 620
 621 void
 622 mkdir_error (char const *name)
 623 {
 624   call_arg_error ("mkdir", name);
 625 }
 626
 627 void
 628 mkfifo_error (char const *name)
 629 {
 630   call_arg_error ("mkfifo", name);
 631 }
 632
 633 void
 634 mknod_error (char const *name)
 635 {
 636   call_arg_error ("mknod", name);
 637 }
 638
 639 void
 640 open_error (char const *name)
 641 {
 642   call_arg_error ("open", name);
 643 }
 644
 645 void
 646 open_fatal (char const *name)
 647 {
 648   call_arg_fatal ("open", name);
 649 }
 650
 651 void
 652 open_warn (char const *name)
 653 {
 654   call_arg_warn ("open", name);
 655 }
 656
 657 void
 658 open_diag (char const *name)
 659 {
 660   if (ignore_failed_read_option)
 661     open_warn (name);
 662   else
 663     open_error (name);
 664 }
 665
 666 void
 667 read_error (char const *name)
 668 {
 669   call_arg_error ("read", name);
 670 }
 671
 672 void
 673 read_error_details (char const *name, off_t offset, size_t size)
 674 {
 675   char buf[UINTMAX_STRSIZE_BOUND];
 676   int e = errno;
 677   ERROR ((0, e,
 678           ngettext ("%s: Read error at byte %s, reading %lu byte",
 679                     "%s: Read error at byte %s, reading %lu bytes",
 680                     size),
 681           quotearg_colon (name), STRINGIFY_BIGINT (offset, buf),
 682           (unsigned long) size));
 683 }
 684
 685 void
 686 read_warn_details (char const *name, off_t offset, size_t size)
 687 {
 688   char buf[UINTMAX_STRSIZE_BOUND];
 689   int e = errno;
 690   WARN ((0, e,
 691          ngettext ("%s: Warning: Read error at byte %s, reading %lu byte",
 692                    "%s: Warning: Read error at byte %s, reading %lu bytes",
 693                    size),
 694          quotearg_colon (name), STRINGIFY_BIGINT (offset, buf),
 695          (unsigned long) size));
 696 }
 697
 698 void
 699 read_diag_details (char const *name, off_t offset, size_t size)
 700 {
 701   if (ignore_failed_read_option)
 702     read_warn_details (name, offset, size);
 703   else
 704     read_error_details (name, offset, size);
 705 }
 706
 707 void
 708 read_fatal (char const *name)
 709 {
 710   call_arg_fatal ("read", name);
 711 }
 712
 713 void
 714 read_fatal_details (char const *name, off_t offset, size_t size)
 715 {
 716   char buf[UINTMAX_STRSIZE_BOUND];
 717   int e = errno;
 718   FATAL_ERROR ((0, e,
 719                 ngettext ("%s: Read error at byte %s, reading %lu byte",
 720                           "%s: Read error at byte %s, reading %lu bytes",
 721                           size),
 722                 quotearg_colon (name), STRINGIFY_BIGINT (offset, buf),
 723                 (unsigned long) size));
 724 }
 725
 726 void
 727 readlink_error (char const *name)
 728 {
 729   call_arg_error ("readlink", name);
 730 }
 731
 732 void
 733 readlink_warn (char const *name)
 734 {
 735   call_arg_warn ("readlink", name);
 736 }
 737
 738 void
 739 readlink_diag (char const *name)
 740 {
 741   if (ignore_failed_read_option)
 742     readlink_warn (name);
 743   else
 744     readlink_error (name);
 745 }
 746
 747 void
 748 savedir_error (char const *name)
 749 {
 750   call_arg_error ("savedir", name);
 751 }
 752
 753 void
 754 savedir_warn (char const *name)
 755 {
 756   call_arg_warn ("savedir", name);
 757 }
 758
 759 void
 760 savedir_diag (char const *name)
 761 {
 762   if (ignore_failed_read_option)
 763     savedir_warn (name);
 764   else
 765     savedir_error (name);
 766 }
 767
 768 void
 769 seek_error (char const *name)
 770 {
 771   call_arg_error ("seek", name);
 772 }
 773
 774 void
 775 seek_error_details (char const *name, off_t offset)
 776 {
 777   char buf[UINTMAX_STRSIZE_BOUND];
 778   int e = errno;
 779   ERROR ((0, e, _("%s: Cannot seek to %s"),
 780           quotearg_colon (name),
 781           STRINGIFY_BIGINT (offset, buf)));
 782 }
 783
 784 void
 785 seek_warn (char const *name)
 786 {
 787   call_arg_warn ("seek", name);
 788 }
 789
 790 void
 791 seek_warn_details (char const *name, off_t offset)
 792 {
 793   char buf[UINTMAX_STRSIZE_BOUND];
 794   int e = errno;
 795   WARN ((0, e, _("%s: Warning: Cannot seek to %s"),
 796          quotearg_colon (name),
 797          STRINGIFY_BIGINT (offset, buf)));
 798 }
 799
 800 void
 801 seek_diag_details (char const *name, off_t offset)
 802 {
 803   if (ignore_failed_read_option)
 804     seek_warn_details (name, offset);
 805   else
 806     seek_error_details (name, offset);
 807 }
 808
 809 void
 810 symlink_error (char const *contents, char const *name)
 811 {
 812   int e = errno;
 813   ERROR ((0, e, _("%s: Cannot create symlink to %s"),
 814           quotearg_colon (name), quote_n (1, contents)));
 815 }
 816
 817 void
 818 stat_error (char const *name)
 819 {
 820   call_arg_error ("stat", name);
 821 }
 822
 823 void
 824 stat_warn (char const *name)
 825 {
 826   call_arg_warn ("stat", name);
 827 }
 828
 829 void
 830 stat_diag (char const *name)
 831 {
 832   if (ignore_failed_read_option)
 833     stat_warn (name);
 834   else
 835     stat_error (name);
 836 }
 837
 838 void
 839 truncate_error (char const *name)
 840 {
 841   call_arg_error ("truncate", name);
 842 }
 843
 844 void
 845 truncate_warn (char const *name)
 846 {
 847   call_arg_warn ("truncate", name);
 848 }
 849
 850 void
 851 unlink_error (char const *name)
 852 {
 853   call_arg_error ("unlink", name);
 854 }
 855
 856 void
 857 utime_error (char const *name)
 858 {
 859   call_arg_error ("utime", name);
 860 }
 861
 862 void
 863 waitpid_error (char const *name)
 864 {
 865   call_arg_error ("waitpid", name);
 866 }
 867
 868 void
 869 write_error (char const *name)
 870 {
 871   call_arg_error ("write", name);
 872 }
 873
 874 void
 875 write_error_details (char const *name, size_t status, size_t size)
 876 {
 877   if (status == 0)
 878     write_error (name);
 879   else
 880     ERROR ((0, 0,
 881             ngettext ("%s: Wrote only %lu of %lu byte",
 882                       "%s: Wrote only %lu of %lu bytes",
 883                       size),
 884             name, (unsigned long int) status, (unsigned long int) size));
 885 }
 886
 887 void
 888 write_fatal (char const *name)
 889 {
 890   call_arg_fatal ("write", name);
 891 }
 892
 893 void
 894 write_fatal_details (char const *name, ssize_t status, size_t size)
 895 {
 896   write_error_details (name, status, size);
 897   fatal_exit ();
 898 }
 899
 900
 901 /* Fork, aborting if unsuccessful.  */
 902 pid_t
 903 xfork (void)
 904 {
 905   pid_t p = fork ();
 906   if (p == (pid_t) -1)
 907     call_arg_fatal ("fork", _("child process"));
 908   return p;
 909 }
 910
 911 /* Create a pipe, aborting if unsuccessful.  */
 912 void
 913 xpipe (int fd[2])
 914 {
 915   if (pipe (fd) < 0)
 916     call_arg_fatal ("pipe", _("interprocess channel"));
 917 }
 918
 919 /* Return PTR, aligned upward to the next multiple of ALIGNMENT.
 920    ALIGNMENT must be nonzero.  The caller must arrange for ((char *)
 921    PTR) through ((char *) PTR + ALIGNMENT - 1) to be addressable
 922    locations.  */
 923
 924 static inline void *
 925 ptr_align (void *ptr, size_t alignment)
 926 {
 927   char *p0 = ptr;
 928   char *p1 = p0 + alignment - 1;
 929   return p1 - (size_t) p1 % alignment;
 930 }
 931
 932 /* Return the address of a page-aligned buffer of at least SIZE bytes.
 933    The caller should free *PTR when done with the buffer.  */
 934
 935 void *
 936 page_aligned_alloc (void **ptr, size_t size)
 937 {
 938   size_t alignment = getpagesize ();
 939   size_t size1 = size + alignment;
 940   if (size1 < size)
 941     xalloc_die ();
 942   *ptr = xmalloc (size1);
 943   return ptr_align (*ptr, alignment);
 944 }