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

   1 /* POSIX extended headers for tar.
   2
   3    Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009, 2010 Free Software
   4    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 <fnmatch.h>
  23 #include <hash.h>
  24 #include <inttostr.h>
  25 #include <quotearg.h>
  26
  27 #include "common.h"
  28
  29 static void xheader_init (struct xheader *xhdr);
  30 static bool xheader_protected_pattern_p (char const *pattern);
  31 static bool xheader_protected_keyword_p (char const *keyword);
  32 static void xheader_set_single_keyword (char *) __attribute__ ((noreturn));
  33
  34 /* Used by xheader_finish() */
  35 static void code_string (char const *string, char const *keyword,
  36                          struct xheader *xhdr);
  37
  38 /* Number of global headers written so far. */
  39 static size_t global_header_count;
  40 /* FIXME: Possibly it should be reset after changing the volume.
  41    POSIX %n specification says that it is expanded to the sequence
  42    number of current global header in *the* archive. However, for
  43    multi-volume archives this will yield duplicate header names
  44    in different volumes, which I'd like to avoid. The best way
  45    to solve this would be to use per-archive header count as required
  46    by POSIX *and* set globexthdr.name to, say,
  47    $TMPDIR/GlobalHead.%p.$NUMVOLUME.%n.
  48
  49    However it should wait until buffer.c is finally rewritten */
  50
  51 \f
  52 /* Interface functions to obstacks */
  53
  54 static void
  55 x_obstack_grow (struct xheader *xhdr, const char *ptr, size_t length)
  56 {
  57   obstack_grow (xhdr->stk, ptr, length);
  58   xhdr->size += length;
  59 }
  60
  61 static void
  62 x_obstack_1grow (struct xheader *xhdr, char c)
  63 {
  64   obstack_1grow (xhdr->stk, c);
  65   xhdr->size++;
  66 }
  67
  68 static void
  69 x_obstack_blank (struct xheader *xhdr, size_t length)
  70 {
  71   obstack_blank (xhdr->stk, length);
  72   xhdr->size += length;
  73 }
  74
  75 \f
  76 /* Keyword options */
  77
  78 struct keyword_list
  79 {
  80   struct keyword_list *next;
  81   char *pattern;
  82   char *value;
  83 };
  84
  85
  86 /* List of keyword patterns set by delete= option */
  87 static struct keyword_list *keyword_pattern_list;
  88
  89 /* List of keyword/value pairs set by `keyword=value' option */
  90 static struct keyword_list *keyword_global_override_list;
  91
  92 /* List of keyword/value pairs set by `keyword:=value' option */
  93 static struct keyword_list *keyword_override_list;
  94
  95 /* List of keyword/value pairs decoded from the last 'g' type header */
  96 static struct keyword_list *global_header_override_list;
  97
  98 /* Template for the name field of an 'x' type header */
  99 static char *exthdr_name;
 100
 101 static char *exthdr_mtime_option;
 102 static time_t exthdr_mtime;
 103
 104 /* Template for the name field of a 'g' type header */
 105 static char *globexthdr_name;
 106
 107 static char *globexthdr_mtime_option;
 108 static time_t globexthdr_mtime;
 109
 110 bool
 111 xheader_keyword_deleted_p (const char *kw)
 112 {
 113   struct keyword_list *kp;
 114
 115   for (kp = keyword_pattern_list; kp; kp = kp->next)
 116     if (fnmatch (kp->pattern, kw, 0) == 0)
 117       return true;
 118   return false;
 119 }
 120
 121 static bool
 122 xheader_keyword_override_p (const char *keyword)
 123 {
 124   struct keyword_list *kp;
 125
 126   for (kp = keyword_override_list; kp; kp = kp->next)
 127     if (strcmp (kp->pattern, keyword) == 0)
 128       return true;
 129   return false;
 130 }
 131
 132 static void
 133 xheader_list_append (struct keyword_list **root, char const *kw,
 134                      char const *value)
 135 {
 136   struct keyword_list *kp = xmalloc (sizeof *kp);
 137   kp->pattern = xstrdup (kw);
 138   kp->value = value ? xstrdup (value) : NULL;
 139   kp->next = *root;
 140   *root = kp;
 141 }
 142
 143 static void
 144 xheader_list_destroy (struct keyword_list **root)
 145 {
 146   if (root)
 147     {
 148       struct keyword_list *kw = *root;
 149       while (kw)
 150         {
 151           struct keyword_list *next = kw->next;
 152           free (kw->pattern);
 153           free (kw->value);
 154           free (kw);
 155           kw = next;
 156         }
 157       *root = NULL;
 158     }
 159 }
 160
 161 static void
 162 xheader_set_single_keyword (char *kw)
 163 {
 164   USAGE_ERROR ((0, 0, _("Keyword %s is unknown or not yet implemented"), kw));
 165 }
 166
 167 static void
 168 assign_time_option (char **sval, time_t *tval, const char *input)
 169 {
 170   uintmax_t u;
 171   char *p;
 172   time_t t = u = strtoumax (input, &p, 10);
 173   if (t != u || *p || errno == ERANGE)
 174     ERROR ((0, 0, _("Time stamp is out of allowed range")));
 175   else
 176     {
 177       *tval = t;
 178       assign_string (sval, input);
 179     }
 180 }
 181
 182 static void
 183 xheader_set_keyword_equal (char *kw, char *eq)
 184 {
 185   bool global = true;
 186   char *p = eq;
 187
 188   if (eq[-1] == ':')
 189     {
 190       p--;
 191       global = false;
 192     }
 193
 194   while (p > kw && isspace ((unsigned char) *p))
 195     p--;
 196
 197   *p = 0;
 198
 199   for (p = eq + 1; *p && isspace ((unsigned char) *p); p++)
 200     ;
 201
 202   if (strcmp (kw, "delete") == 0)
 203     {
 204       if (xheader_protected_pattern_p (p))
 205         USAGE_ERROR ((0, 0, _("Pattern %s cannot be used"), quote (p)));
 206       xheader_list_append (&keyword_pattern_list, p, NULL);
 207     }
 208   else if (strcmp (kw, "exthdr.name") == 0)
 209     assign_string (&exthdr_name, p);
 210   else if (strcmp (kw, "globexthdr.name") == 0)
 211     assign_string (&globexthdr_name, p);
 212   else if (strcmp (kw, "exthdr.mtime") == 0)
 213     assign_time_option (&exthdr_mtime_option, &exthdr_mtime, p);
 214   else if (strcmp (kw, "globexthdr.mtime") == 0)
 215     assign_time_option (&globexthdr_mtime_option, &globexthdr_mtime, p);
 216   else
 217     {
 218       if (xheader_protected_keyword_p (kw))
 219         USAGE_ERROR ((0, 0, _("Keyword %s cannot be overridden"), kw));
 220       if (global)
 221         xheader_list_append (&keyword_global_override_list, kw, p);
 222       else
 223         xheader_list_append (&keyword_override_list, kw, p);
 224     }
 225 }
 226
 227 void
 228 xheader_set_option (char *string)
 229 {
 230   char *token;
 231   for (token = strtok (string, ","); token; token = strtok (NULL, ","))
 232     {
 233       char *p = strchr (token, '=');
 234       if (!p)
 235         xheader_set_single_keyword (token);
 236       else
 237         xheader_set_keyword_equal (token, p);
 238     }
 239 }
 240
 241 /*
 242     string Includes:          Replaced By:
 243      %d                       The directory name of the file,
 244                               equivalent to the result of the
 245                               dirname utility on the translated
 246                               file name.
 247      %f                       The filename of the file, equivalent
 248                               to the result of the basename
 249                               utility on the translated file name.
 250      %p                       The process ID of the pax process.
 251      %n                       The value of the 3rd argument.
 252      %%                       A '%' character. */
 253
 254 char *
 255 xheader_format_name (struct tar_stat_info *st, const char *fmt, size_t n)
 256 {
 257   char *buf;
 258   size_t len = strlen (fmt);
 259   char *q;
 260   const char *p;
 261   char *dirp = NULL;
 262   char *dir = NULL;
 263   char *base = NULL;
 264   char pidbuf[UINTMAX_STRSIZE_BOUND];
 265   char const *pptr;
 266   char nbuf[UINTMAX_STRSIZE_BOUND];
 267   char const *nptr = NULL;
 268
 269   for (p = fmt; *p && (p = strchr (p, '%')); )
 270     {
 271       switch (p[1])
 272         {
 273         case '%':
 274           len--;
 275           break;
 276
 277         case 'd':
 278           if (st)
 279             {
 280               if (!dirp)
 281                 dirp = dir_name (st->orig_file_name);
 282               dir = safer_name_suffix (dirp, false, absolute_names_option);
 283               len += strlen (dir) - 2;
 284             }
 285           break;
 286
 287         case 'f':
 288           if (st)
 289             {
 290               base = last_component (st->orig_file_name);
 291               len += strlen (base) - 2;
 292             }
 293           break;
 294
 295         case 'p':
 296           pptr = umaxtostr (getpid (), pidbuf);
 297           len += pidbuf + sizeof pidbuf - 1 - pptr - 2;
 298           break;
 299
 300         case 'n':
 301           nptr = umaxtostr (n, nbuf);
 302           len += nbuf + sizeof nbuf - 1 - nptr - 2;
 303           break;
 304         }
 305       p++;
 306     }
 307
 308   buf = xmalloc (len + 1);
 309   for (q = buf, p = fmt; *p; )
 310     {
 311       if (*p == '%')
 312         {
 313           switch (p[1])
 314             {
 315             case '%':
 316               *q++ = *p++;
 317               p++;
 318               break;
 319
 320             case 'd':
 321               if (dir)
 322                 q = stpcpy (q, dir);
 323               p += 2;
 324               break;
 325
 326             case 'f':
 327               if (base)
 328                 q = stpcpy (q, base);
 329               p += 2;
 330               break;
 331
 332             case 'p':
 333               q = stpcpy (q, pptr);
 334               p += 2;
 335               break;
 336
 337             case 'n':
 338               if (nptr)
 339                 {
 340                   q = stpcpy (q, nptr);
 341                   p += 2;
 342                   break;
 343                 }
 344               /* else fall through */
 345
 346             default:
 347               *q++ = *p++;
 348               if (*p)
 349                 *q++ = *p++;
 350             }
 351         }
 352       else
 353         *q++ = *p++;
 354     }
 355
 356   free (dirp);
 357
 358   /* Do not allow it to end in a slash */
 359   while (q > buf && ISSLASH (q[-1]))
 360     q--;
 361   *q = 0;
 362   return buf;
 363 }
 364
 365 char *
 366 xheader_xhdr_name (struct tar_stat_info *st)
 367 {
 368   if (!exthdr_name)
 369     assign_string (&exthdr_name, "%d/PaxHeaders.%p/%f");
 370   return xheader_format_name (st, exthdr_name, 0);
 371 }
 372
 373 #define GLOBAL_HEADER_TEMPLATE "/GlobalHead.%p.%n"
 374
 375 char *
 376 xheader_ghdr_name (void)
 377 {
 378   if (!globexthdr_name)
 379     {
 380       size_t len;
 381       const char *tmp = getenv ("TMPDIR");
 382       if (!tmp)
 383         tmp = "/tmp";
 384       len = strlen (tmp) + sizeof (GLOBAL_HEADER_TEMPLATE); /* Includes nul */
 385       globexthdr_name = xmalloc (len);
 386       strcpy(globexthdr_name, tmp);
 387       strcat(globexthdr_name, GLOBAL_HEADER_TEMPLATE);
 388     }
 389
 390   return xheader_format_name (NULL, globexthdr_name, global_header_count + 1);
 391 }
 392
 393 void
 394 xheader_write (char type, char *name, time_t t, struct xheader *xhdr)
 395 {
 396   union block *header;
 397   size_t size;
 398   char *p;
 399
 400   size = xhdr->size;
 401   switch (type)
 402     {
 403     case XGLTYPE:
 404       if (globexthdr_mtime_option)
 405         t = globexthdr_mtime;
 406       break;
 407
 408     case XHDTYPE:
 409       if (exthdr_mtime_option)
 410         t = exthdr_mtime;
 411       break;
 412     }
 413   header = start_private_header (name, size, t);
 414   header->header.typeflag = type;
 415
 416   simple_finish_header (header);
 417
 418   p = xhdr->buffer;
 419
 420   do
 421     {
 422       size_t len;
 423
 424       header = find_next_block ();
 425       len = BLOCKSIZE;
 426       if (len > size)
 427         len = size;
 428       memcpy (header->buffer, p, len);
 429       if (len < BLOCKSIZE)
 430         memset (header->buffer + len, 0, BLOCKSIZE - len);
 431       p += len;
 432       size -= len;
 433       set_next_block_after (header);
 434     }
 435   while (size > 0);
 436   xheader_destroy (xhdr);
 437
 438   if (type == XGLTYPE)
 439     global_header_count++;
 440 }
 441
 442 void
 443 xheader_write_global (struct xheader *xhdr)
 444 {
 445   if (keyword_global_override_list)
 446     {
 447       struct keyword_list *kp;
 448
 449       xheader_init (xhdr);
 450       for (kp = keyword_global_override_list; kp; kp = kp->next)
 451         code_string (kp->value, kp->pattern, xhdr);
 452     }
 453   if (xhdr->stk)
 454     {
 455       char *name;
 456
 457       xheader_finish (xhdr);
 458       xheader_write (XGLTYPE, name = xheader_ghdr_name (), time (NULL), xhdr);
 459       free (name);
 460     }
 461 }
 462
 463 \f
 464 /* General Interface */
 465
 466 #define XHDR_PROTECTED 0x01
 467 #define XHDR_GLOBAL    0x02
 468
 469 struct xhdr_tab
 470 {
 471   char const *keyword;
 472   void (*coder) (struct tar_stat_info const *, char const *,
 473                  struct xheader *, void const *data);
 474   void (*decoder) (struct tar_stat_info *, char const *, char const *, size_t);
 475   int flags;
 476 };
 477
 478 /* This declaration must be extern, because ISO C99 section 6.9.2
 479    prohibits a tentative definition that has both internal linkage and
 480    incomplete type.  If we made it static, we'd have to declare its
 481    size which would be a maintenance pain; if we put its initializer
 482    here, we'd need a boatload of forward declarations, which would be
 483    even more of a pain.  */
 484 extern struct xhdr_tab const xhdr_tab[];
 485
 486 static struct xhdr_tab const *
 487 locate_handler (char const *keyword)
 488 {
 489   struct xhdr_tab const *p;
 490
 491   for (p = xhdr_tab; p->keyword; p++)
 492     if (strcmp (p->keyword, keyword) == 0)
 493       return p;
 494   return NULL;
 495 }
 496
 497 static bool
 498 xheader_protected_pattern_p (const char *pattern)
 499 {
 500   struct xhdr_tab const *p;
 501
 502   for (p = xhdr_tab; p->keyword; p++)
 503     if ((p->flags & XHDR_PROTECTED) && fnmatch (pattern, p->keyword, 0) == 0)
 504       return true;
 505   return false;
 506 }
 507
 508 static bool
 509 xheader_protected_keyword_p (const char *keyword)
 510 {
 511   struct xhdr_tab const *p;
 512
 513   for (p = xhdr_tab; p->keyword; p++)
 514     if ((p->flags & XHDR_PROTECTED) && strcmp (p->keyword, keyword) == 0)
 515       return true;
 516   return false;
 517 }
 518
 519 /* Decode a single extended header record, advancing *PTR to the next record.
 520    Return true on success, false otherwise.  */
 521 static bool
 522 decode_record (struct xheader *xhdr,
 523                char **ptr,
 524                void (*handler) (void *, char const *, char const *, size_t),
 525                void *data)
 526 {
 527   char *start = *ptr;
 528   char *p = start;
 529   uintmax_t u;
 530   size_t len;
 531   char *len_lim;
 532   char const *keyword;
 533   char *nextp;
 534   size_t len_max = xhdr->buffer + xhdr->size - start;
 535
 536   while (*p == ' ' || *p == '\t')
 537     p++;
 538
 539   if (! ISDIGIT (*p))
 540     {
 541       if (*p)
 542         ERROR ((0, 0, _("Malformed extended header: missing length")));
 543       return false;
 544     }
 545
 546   errno = 0;
 547   len = u = strtoumax (p, &len_lim, 10);
 548   if (len != u || errno == ERANGE)
 549     {
 550       ERROR ((0, 0, _("Extended header length is out of allowed range")));
 551       return false;
 552     }
 553
 554   if (len_max < len)
 555     {
 556       int len_len = len_lim - p;
 557       ERROR ((0, 0, _("Extended header length %*s is out of range"),
 558               len_len, p));
 559       return false;
 560     }
 561
 562   nextp = start + len;
 563
 564   for (p = len_lim; *p == ' ' || *p == '\t'; p++)
 565     continue;
 566   if (p == len_lim)
 567     {
 568       ERROR ((0, 0,
 569               _("Malformed extended header: missing blank after length")));
 570       return false;
 571     }
 572
 573   keyword = p;
 574   p = strchr (p, '=');
 575   if (! (p && p < nextp))
 576     {
 577       ERROR ((0, 0, _("Malformed extended header: missing equal sign")));
 578       return false;
 579     }
 580
 581   if (nextp[-1] != '\n')
 582     {
 583       ERROR ((0, 0, _("Malformed extended header: missing newline")));
 584       return false;
 585     }
 586
 587   *p = nextp[-1] = '\0';
 588   handler (data, keyword, p + 1, nextp - p - 2); /* '=' + trailing '\n' */
 589   *p = '=';
 590   nextp[-1] = '\n';
 591   *ptr = nextp;
 592   return true;
 593 }
 594
 595 static void
 596 run_override_list (struct keyword_list *kp, struct tar_stat_info *st)
 597 {
 598   for (; kp; kp = kp->next)
 599     {
 600       struct xhdr_tab const *t = locate_handler (kp->pattern);
 601       if (t)
 602         t->decoder (st, t->keyword, kp->value, strlen (kp->value));
 603     }
 604 }
 605
 606 static void
 607 decx (void *data, char const *keyword, char const *value, size_t size)
 608 {
 609   struct xhdr_tab const *t;
 610   struct tar_stat_info *st = data;
 611
 612   if (xheader_keyword_deleted_p (keyword)
 613       || xheader_keyword_override_p (keyword))
 614     return;
 615
 616   t = locate_handler (keyword);
 617   if (t)
 618     t->decoder (st, keyword, value, size);
 619   else
 620     WARNOPT (WARN_UNKNOWN_KEYWORD,
 621              (0, 0, _("Ignoring unknown extended header keyword `%s'"),
 622               keyword));
 623 }
 624
 625 void
 626 xheader_decode (struct tar_stat_info *st)
 627 {
 628   run_override_list (keyword_global_override_list, st);
 629   run_override_list (global_header_override_list, st);
 630
 631   if (st->xhdr.size)
 632     {
 633       char *p = st->xhdr.buffer + BLOCKSIZE;
 634       while (decode_record (&st->xhdr, &p, decx, st))
 635         continue;
 636     }
 637   run_override_list (keyword_override_list, st);
 638 }
 639
 640 static void
 641 decg (void *data, char const *keyword, char const *value,
 642       size_t size __attribute__((unused)))
 643 {
 644   struct keyword_list **kwl = data;
 645   struct xhdr_tab const *tab = locate_handler (keyword);
 646   if (tab && (tab->flags & XHDR_GLOBAL))
 647     tab->decoder (data, keyword, value, size);
 648   else
 649     xheader_list_append (kwl, keyword, value);
 650 }
 651
 652 void
 653 xheader_decode_global (struct xheader *xhdr)
 654 {
 655   if (xhdr->size)
 656     {
 657       char *p = xhdr->buffer + BLOCKSIZE;
 658
 659       xheader_list_destroy (&global_header_override_list);
 660       while (decode_record (xhdr, &p, decg, &global_header_override_list))
 661         continue;
 662     }
 663 }
 664
 665 static void
 666 xheader_init (struct xheader *xhdr)
 667 {
 668   if (!xhdr->stk)
 669     {
 670       xhdr->stk = xmalloc (sizeof *xhdr->stk);
 671       obstack_init (xhdr->stk);
 672     }
 673 }
 674
 675 void
 676 xheader_store (char const *keyword, struct tar_stat_info *st,
 677                void const *data)
 678 {
 679   struct xhdr_tab const *t;
 680
 681   if (st->xhdr.buffer)
 682     return;
 683   t = locate_handler (keyword);
 684   if (!t || !t->coder)
 685     return;
 686   if (xheader_keyword_deleted_p (keyword)
 687       || xheader_keyword_override_p (keyword))
 688     return;
 689   xheader_init (&st->xhdr);
 690   t->coder (st, keyword, &st->xhdr, data);
 691 }
 692
 693 void
 694 xheader_read (struct xheader *xhdr, union block *p, size_t size)
 695 {
 696   size_t j = 0;
 697
 698   size += BLOCKSIZE;
 699   xhdr->size = size;
 700   xhdr->buffer = xmalloc (size + 1);
 701   xhdr->buffer[size] = '\0';
 702
 703   do
 704     {
 705       size_t len = size;
 706
 707       if (len > BLOCKSIZE)
 708         len = BLOCKSIZE;
 709
 710       if (!p)
 711         FATAL_ERROR ((0, 0, _("Unexpected EOF in archive")));
 712
 713       memcpy (&xhdr->buffer[j], p->buffer, len);
 714       set_next_block_after (p);
 715
 716       p = find_next_block ();
 717
 718       j += len;
 719       size -= len;
 720     }
 721   while (size > 0);
 722 }
 723
 724 static void
 725 xheader_print_n (struct xheader *xhdr, char const *keyword,
 726                  char const *value, size_t vsize)
 727 {
 728   size_t len = strlen (keyword) + vsize + 3; /* ' ' + '=' + '\n' */
 729   size_t p;
 730   size_t n = 0;
 731   char nbuf[UINTMAX_STRSIZE_BOUND];
 732   char const *np;
 733
 734   do
 735     {
 736       p = n;
 737       np = umaxtostr (len + p, nbuf);
 738       n = nbuf + sizeof nbuf - 1 - np;
 739     }
 740   while (n != p);
 741
 742   x_obstack_grow (xhdr, np, n);
 743   x_obstack_1grow (xhdr, ' ');
 744   x_obstack_grow (xhdr, keyword, strlen (keyword));
 745   x_obstack_1grow (xhdr, '=');
 746   x_obstack_grow (xhdr, value, vsize);
 747   x_obstack_1grow (xhdr, '\n');
 748 }
 749
 750 static void
 751 xheader_print (struct xheader *xhdr, char const *keyword, char const *value)
 752 {
 753   xheader_print_n (xhdr, keyword, value, strlen (value));
 754 }
 755
 756 void
 757 xheader_finish (struct xheader *xhdr)
 758 {
 759   struct keyword_list *kp;
 760
 761   for (kp = keyword_override_list; kp; kp = kp->next)
 762     code_string (kp->value, kp->pattern, xhdr);
 763
 764   xhdr->buffer = obstack_finish (xhdr->stk);
 765 }
 766
 767 void
 768 xheader_destroy (struct xheader *xhdr)
 769 {
 770   if (xhdr->stk)
 771     {
 772       obstack_free (xhdr->stk, NULL);
 773       free (xhdr->stk);
 774       xhdr->stk = NULL;
 775     }
 776   else
 777     free (xhdr->buffer);
 778   xhdr->buffer = 0;
 779   xhdr->size = 0;
 780 }
 781
 782 \f
 783 /* Buildable strings */
 784
 785 void
 786 xheader_string_begin (struct xheader *xhdr)
 787 {
 788   xhdr->string_length = 0;
 789 }
 790
 791 void
 792 xheader_string_add (struct xheader *xhdr, char const *s)
 793 {
 794   if (xhdr->buffer)
 795     return;
 796   xheader_init (xhdr);
 797   xhdr->string_length += strlen (s);
 798   x_obstack_grow (xhdr, s, strlen (s));
 799 }
 800
 801 bool
 802 xheader_string_end (struct xheader *xhdr, char const *keyword)
 803 {
 804   uintmax_t len;
 805   uintmax_t p;
 806   uintmax_t n = 0;
 807   size_t size;
 808   char nbuf[UINTMAX_STRSIZE_BOUND];
 809   char const *np;
 810   char *cp;
 811
 812   if (xhdr->buffer)
 813     return false;
 814   xheader_init (xhdr);
 815
 816   len = strlen (keyword) + xhdr->string_length + 3; /* ' ' + '=' + '\n' */
 817
 818   do
 819     {
 820       p = n;
 821       np = umaxtostr (len + p, nbuf);
 822       n = nbuf + sizeof nbuf - 1 - np;
 823     }
 824   while (n != p);
 825
 826   p = strlen (keyword) + n + 2;
 827   size = p;
 828   if (size != p)
 829     {
 830       ERROR ((0, 0,
 831         _("Generated keyword/value pair is too long (keyword=%s, length=%s)"),
 832               keyword, nbuf));
 833       obstack_free (xhdr->stk, obstack_finish (xhdr->stk));
 834       return false;
 835     }
 836   x_obstack_blank (xhdr, p);
 837   x_obstack_1grow (xhdr, '\n');
 838   cp = obstack_next_free (xhdr->stk) - xhdr->string_length - p - 1;
 839   memmove (cp + p, cp, xhdr->string_length);
 840   cp = stpcpy (cp, np);
 841   *cp++ = ' ';
 842   cp = stpcpy (cp, keyword);
 843   *cp++ = '=';
 844   return true;
 845 }
 846
 847 \f
 848 /* Implementations */
 849
 850 static void
 851 out_of_range_header (char const *keyword, char const *value,
 852                      uintmax_t minus_minval, uintmax_t maxval)
 853 {
 854   char minval_buf[UINTMAX_STRSIZE_BOUND + 1];
 855   char maxval_buf[UINTMAX_STRSIZE_BOUND];
 856   char *minval_string = umaxtostr (minus_minval, minval_buf + 1);
 857   char *maxval_string = umaxtostr (maxval, maxval_buf);
 858   if (minus_minval)
 859     *--minval_string = '-';
 860
 861   /* TRANSLATORS: The first %s is the pax extended header keyword
 862      (atime, gid, etc.).  */
 863   ERROR ((0, 0, _("Extended header %s=%s is out of range %s..%s"),
 864           keyword, value, minval_string, maxval_string));
 865 }
 866
 867 static void
 868 code_string (char const *string, char const *keyword, struct xheader *xhdr)
 869 {
 870   char *outstr;
 871   if (!utf8_convert (true, string, &outstr))
 872     {
 873       /* FIXME: report error */
 874       outstr = xstrdup (string);
 875     }
 876   xheader_print (xhdr, keyword, outstr);
 877   free (outstr);
 878 }
 879
 880 static void
 881 decode_string (char **string, char const *arg)
 882 {
 883   if (*string)
 884     {
 885       free (*string);
 886       *string = NULL;
 887     }
 888   if (!utf8_convert (false, arg, string))
 889     {
 890       /* FIXME: report error and act accordingly to --pax invalid=UTF-8 */
 891       assign_string (string, arg);
 892     }
 893 }
 894
 895 static void
 896 code_time (struct timespec t, char const *keyword, struct xheader *xhdr)
 897 {
 898   char buf[TIMESPEC_STRSIZE_BOUND];
 899   xheader_print (xhdr, keyword, code_timespec (t, buf));
 900 }
 901
 902 enum decode_time_status
 903   {
 904     decode_time_success,
 905     decode_time_range,
 906     decode_time_bad_header
 907   };
 908
 909 static enum decode_time_status
 910 _decode_time (struct timespec *ts, char const *arg, char const *keyword)
 911 {
 912   time_t s;
 913   unsigned long int ns = 0;
 914   char *p;
 915   char *arg_lim;
 916   bool negative = *arg == '-';
 917
 918   errno = 0;
 919
 920   if (ISDIGIT (arg[negative]))
 921     {
 922       if (negative)
 923         {
 924           intmax_t i = strtoimax (arg, &arg_lim, 10);
 925           if (TYPE_SIGNED (time_t) ? i < TYPE_MINIMUM (time_t) : i < 0)
 926             return decode_time_range;
 927           s = i;
 928         }
 929       else
 930         {
 931           uintmax_t i = strtoumax (arg, &arg_lim, 10);
 932           if (TYPE_MAXIMUM (time_t) < i)
 933             return decode_time_range;
 934           s = i;
 935         }
 936
 937       p = arg_lim;
 938
 939       if (errno == ERANGE)
 940         return decode_time_range;
 941
 942       if (*p == '.')
 943         {
 944           int digits = 0;
 945           bool trailing_nonzero = false;
 946
 947           while (ISDIGIT (*++p))
 948             if (digits < LOG10_BILLION)
 949               {
 950                 ns = 10 * ns + (*p - '0');
 951                 digits++;
 952               }
 953             else
 954               trailing_nonzero |= *p != '0';
 955
 956           while (digits++ < LOG10_BILLION)
 957             ns *= 10;
 958
 959           if (negative)
 960             {
 961               /* Convert "-1.10000000000001" to s == -2, ns == 89999999.
 962                  I.e., truncate time stamps towards minus infinity while
 963                  converting them to internal form.  */
 964               ns += trailing_nonzero;
 965               if (ns != 0)
 966                 {
 967                   if (s == TYPE_MINIMUM (time_t))
 968                     return decode_time_range;
 969                   s--;
 970                   ns = BILLION - ns;
 971                 }
 972             }
 973         }
 974
 975       if (! *p)
 976         {
 977           ts->tv_sec = s;
 978           ts->tv_nsec = ns;
 979           return decode_time_success;
 980         }
 981     }
 982
 983   return decode_time_bad_header;
 984 }
 985
 986 static bool
 987 decode_time (struct timespec *ts, char const *arg, char const *keyword)
 988 {
 989   switch (_decode_time (ts, arg, keyword))
 990     {
 991     case decode_time_success:
 992       return true;
 993     case decode_time_bad_header:
 994       ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
 995               keyword, arg));
 996       return false;
 997     case decode_time_range:
 998       out_of_range_header (keyword, arg, - (uintmax_t) TYPE_MINIMUM (time_t),
 999                            TYPE_MAXIMUM (time_t));
1000       return false;
1001     }
1002   return true;
1003 }
1004
1005
1006
1007 static void
1008 code_num (uintmax_t value, char const *keyword, struct xheader *xhdr)
1009 {
1010   char sbuf[UINTMAX_STRSIZE_BOUND];
1011   xheader_print (xhdr, keyword, umaxtostr (value, sbuf));
1012 }
1013
1014 static bool
1015 decode_num (uintmax_t *num, char const *arg, uintmax_t maxval,
1016             char const *keyword)
1017 {
1018   uintmax_t u;
1019   char *arg_lim;
1020
1021   if (! (ISDIGIT (*arg)
1022          && (errno = 0, u = strtoumax (arg, &arg_lim, 10), !*arg_lim)))
1023     {
1024       ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
1025               keyword, arg));
1026       return false;
1027     }
1028
1029   if (! (u <= maxval && errno != ERANGE))
1030     {
1031       out_of_range_header (keyword, arg, 0, maxval);
1032       return false;
1033     }
1034
1035   *num = u;
1036   return true;
1037 }
1038
1039 static void
1040 dummy_coder (struct tar_stat_info const *st __attribute__ ((unused)),
1041              char const *keyword __attribute__ ((unused)),
1042              struct xheader *xhdr __attribute__ ((unused)),
1043              void const *data __attribute__ ((unused)))
1044 {
1045 }
1046
1047 static void
1048 dummy_decoder (struct tar_stat_info *st __attribute__ ((unused)),
1049                char const *keyword __attribute__ ((unused)),
1050                char const *arg __attribute__ ((unused)),
1051                size_t size __attribute__((unused)))
1052 {
1053 }
1054
1055 static void
1056 atime_coder (struct tar_stat_info const *st, char const *keyword,
1057              struct xheader *xhdr, void const *data __attribute__ ((unused)))
1058 {
1059   code_time (st->atime, keyword, xhdr);
1060 }
1061
1062 static void
1063 atime_decoder (struct tar_stat_info *st,
1064                char const *keyword,
1065                char const *arg,
1066                size_t size __attribute__((unused)))
1067 {
1068   struct timespec ts;
1069   if (decode_time (&ts, arg, keyword))
1070     st->atime = ts;
1071 }
1072
1073 static void
1074 gid_coder (struct tar_stat_info const *st, char const *keyword,
1075            struct xheader *xhdr, void const *data __attribute__ ((unused)))
1076 {
1077   code_num (st->stat.st_gid, keyword, xhdr);
1078 }
1079
1080 static void
1081 gid_decoder (struct tar_stat_info *st,
1082              char const *keyword,
1083              char const *arg,
1084              size_t size __attribute__((unused)))
1085 {
1086   uintmax_t u;
1087   if (decode_num (&u, arg, TYPE_MAXIMUM (gid_t), keyword))
1088     st->stat.st_gid = u;
1089 }
1090
1091 static void
1092 gname_coder (struct tar_stat_info const *st, char const *keyword,
1093              struct xheader *xhdr, void const *data __attribute__ ((unused)))
1094 {
1095   code_string (st->gname, keyword, xhdr);
1096 }
1097
1098 static void
1099 gname_decoder (struct tar_stat_info *st,
1100                char const *keyword __attribute__((unused)),
1101                char const *arg,
1102                size_t size __attribute__((unused)))
1103 {
1104   decode_string (&st->gname, arg);
1105 }
1106
1107 static void
1108 linkpath_coder (struct tar_stat_info const *st, char const *keyword,
1109                 struct xheader *xhdr, void const *data __attribute__ ((unused)))
1110 {
1111   code_string (st->link_name, keyword, xhdr);
1112 }
1113
1114 static void
1115 linkpath_decoder (struct tar_stat_info *st,
1116                   char const *keyword __attribute__((unused)),
1117                   char const *arg,
1118                   size_t size __attribute__((unused)))
1119 {
1120   decode_string (&st->link_name, arg);
1121 }
1122
1123 static void
1124 ctime_coder (struct tar_stat_info const *st, char const *keyword,
1125              struct xheader *xhdr, void const *data __attribute__ ((unused)))
1126 {
1127   code_time (st->ctime, keyword, xhdr);
1128 }
1129
1130 static void
1131 ctime_decoder (struct tar_stat_info *st,
1132                char const *keyword,
1133                char const *arg,
1134                size_t size __attribute__((unused)))
1135 {
1136   struct timespec ts;
1137   if (decode_time (&ts, arg, keyword))
1138     st->ctime = ts;
1139 }
1140
1141 static void
1142 mtime_coder (struct tar_stat_info const *st, char const *keyword,
1143              struct xheader *xhdr, void const *data)
1144 {
1145   struct timespec const *mtime = data;
1146   code_time (mtime ? *mtime : st->mtime, keyword, xhdr);
1147 }
1148
1149 static void
1150 mtime_decoder (struct tar_stat_info *st,
1151                char const *keyword,
1152                char const *arg,
1153                size_t size __attribute__((unused)))
1154 {
1155   struct timespec ts;
1156   if (decode_time (&ts, arg, keyword))
1157     st->mtime = ts;
1158 }
1159
1160 static void
1161 path_coder (struct tar_stat_info const *st, char const *keyword,
1162             struct xheader *xhdr, void const *data __attribute__ ((unused)))
1163 {
1164   code_string (st->file_name, keyword, xhdr);
1165 }
1166
1167 static void
1168 path_decoder (struct tar_stat_info *st,
1169               char const *keyword __attribute__((unused)),
1170               char const *arg,
1171               size_t size __attribute__((unused)))
1172 {
1173   decode_string (&st->orig_file_name, arg);
1174   decode_string (&st->file_name, arg);
1175   st->had_trailing_slash = strip_trailing_slashes (st->file_name);
1176 }
1177
1178 static void
1179 size_coder (struct tar_stat_info const *st, char const *keyword,
1180             struct xheader *xhdr, void const *data __attribute__ ((unused)))
1181 {
1182   code_num (st->stat.st_size, keyword, xhdr);
1183 }
1184
1185 static void
1186 size_decoder (struct tar_stat_info *st,
1187               char const *keyword,
1188               char const *arg,
1189               size_t size __attribute__((unused)))
1190 {
1191   uintmax_t u;
1192   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), keyword))
1193     st->stat.st_size = u;
1194 }
1195
1196 static void
1197 uid_coder (struct tar_stat_info const *st, char const *keyword,
1198            struct xheader *xhdr, void const *data __attribute__ ((unused)))
1199 {
1200   code_num (st->stat.st_uid, keyword, xhdr);
1201 }
1202
1203 static void
1204 uid_decoder (struct tar_stat_info *st,
1205              char const *keyword,
1206              char const *arg,
1207              size_t size __attribute__((unused)))
1208 {
1209   uintmax_t u;
1210   if (decode_num (&u, arg, TYPE_MAXIMUM (uid_t), keyword))
1211     st->stat.st_uid = u;
1212 }
1213
1214 static void
1215 uname_coder (struct tar_stat_info const *st, char const *keyword,
1216              struct xheader *xhdr, void const *data __attribute__ ((unused)))
1217 {
1218   code_string (st->uname, keyword, xhdr);
1219 }
1220
1221 static void
1222 uname_decoder (struct tar_stat_info *st,
1223                char const *keyword __attribute__((unused)),
1224                char const *arg,
1225                size_t size __attribute__((unused)))
1226 {
1227   decode_string (&st->uname, arg);
1228 }
1229
1230 static void
1231 sparse_size_coder (struct tar_stat_info const *st, char const *keyword,
1232              struct xheader *xhdr, void const *data)
1233 {
1234   size_coder (st, keyword, xhdr, data);
1235 }
1236
1237 static void
1238 sparse_size_decoder (struct tar_stat_info *st,
1239                      char const *keyword,
1240                      char const *arg,
1241                      size_t size __attribute__((unused)))
1242 {
1243   uintmax_t u;
1244   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), keyword))
1245     st->stat.st_size = u;
1246 }
1247
1248 static void
1249 sparse_numblocks_coder (struct tar_stat_info const *st, char const *keyword,
1250                         struct xheader *xhdr,
1251                         void const *data __attribute__ ((unused)))
1252 {
1253   code_num (st->sparse_map_avail, keyword, xhdr);
1254 }
1255
1256 static void
1257 sparse_numblocks_decoder (struct tar_stat_info *st,
1258                           char const *keyword,
1259                           char const *arg,
1260                           size_t size __attribute__((unused)))
1261 {
1262   uintmax_t u;
1263   if (decode_num (&u, arg, SIZE_MAX, keyword))
1264     {
1265       st->sparse_map_size = u;
1266       st->sparse_map = xcalloc (u, sizeof st->sparse_map[0]);
1267       st->sparse_map_avail = 0;
1268     }
1269 }
1270
1271 static void
1272 sparse_offset_coder (struct tar_stat_info const *st, char const *keyword,
1273                      struct xheader *xhdr, void const *data)
1274 {
1275   size_t const *pi = data;
1276   code_num (st->sparse_map[*pi].offset, keyword, xhdr);
1277 }
1278
1279 static void
1280 sparse_offset_decoder (struct tar_stat_info *st,
1281                        char const *keyword,
1282                        char const *arg,
1283                        size_t size __attribute__((unused)))
1284 {
1285   uintmax_t u;
1286   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), keyword))
1287     {
1288       if (st->sparse_map_avail < st->sparse_map_size)
1289         st->sparse_map[st->sparse_map_avail].offset = u;
1290       else
1291         ERROR ((0, 0, _("Malformed extended header: excess %s=%s"),
1292                 "GNU.sparse.offset", arg));
1293     }
1294 }
1295
1296 static void
1297 sparse_numbytes_coder (struct tar_stat_info const *st, char const *keyword,
1298                        struct xheader *xhdr, void const *data)
1299 {
1300   size_t const *pi = data;
1301   code_num (st->sparse_map[*pi].numbytes, keyword, xhdr);
1302 }
1303
1304 static void
1305 sparse_numbytes_decoder (struct tar_stat_info *st,
1306                          char const *keyword,
1307                          char const *arg,
1308                          size_t size __attribute__((unused)))
1309 {
1310   uintmax_t u;
1311   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), keyword))
1312     {
1313       if (st->sparse_map_avail < st->sparse_map_size)
1314         st->sparse_map[st->sparse_map_avail++].numbytes = u;
1315       else
1316         ERROR ((0, 0, _("Malformed extended header: excess %s=%s"),
1317                 keyword, arg));
1318     }
1319 }
1320
1321 static void
1322 sparse_map_decoder (struct tar_stat_info *st,
1323                     char const *keyword,
1324                     char const *arg,
1325                     size_t size __attribute__((unused)))
1326 {
1327   int offset = 1;
1328
1329   st->sparse_map_avail = 0;
1330   while (1)
1331     {
1332       uintmax_t u;
1333       char *delim;
1334       struct sp_array e;
1335
1336       if (!ISDIGIT (*arg))
1337         {
1338           ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
1339                   keyword, arg));
1340           return;
1341         }
1342
1343       errno = 0;
1344       u = strtoumax (arg, &delim, 10);
1345       if (offset)
1346         {
1347           e.offset = u;
1348           if (!(u == e.offset && errno != ERANGE))
1349             {
1350               out_of_range_header (keyword, arg, 0, TYPE_MAXIMUM (off_t));
1351               return;
1352             }
1353         }
1354       else
1355         {
1356           e.numbytes = u;
1357           if (!(u == e.numbytes && errno != ERANGE))
1358             {
1359               out_of_range_header (keyword, arg, 0, TYPE_MAXIMUM (off_t));
1360               return;
1361             }
1362           if (st->sparse_map_avail < st->sparse_map_size)
1363             st->sparse_map[st->sparse_map_avail++] = e;
1364           else
1365             {
1366               ERROR ((0, 0, _("Malformed extended header: excess %s=%s"),
1367                       keyword, arg));
1368               return;
1369             }
1370         }
1371
1372       offset = !offset;
1373
1374       if (*delim == 0)
1375         break;
1376       else if (*delim != ',')
1377         {
1378           ERROR ((0, 0,
1379                   _("Malformed extended header: invalid %s: unexpected delimiter %c"),
1380                   keyword, *delim));
1381           return;
1382         }
1383
1384       arg = delim + 1;
1385     }
1386
1387   if (!offset)
1388     ERROR ((0, 0,
1389             _("Malformed extended header: invalid %s: odd number of values"),
1390             keyword));
1391 }
1392
1393 static void
1394 dumpdir_coder (struct tar_stat_info const *st, char const *keyword,
1395                struct xheader *xhdr, void const *data)
1396 {
1397   xheader_print_n (xhdr, keyword, data, dumpdir_size (data));
1398 }
1399
1400 static void
1401 dumpdir_decoder (struct tar_stat_info *st,
1402                  char const *keyword __attribute__((unused)),
1403                  char const *arg,
1404                  size_t size)
1405 {
1406   st->dumpdir = xmalloc (size);
1407   memcpy (st->dumpdir, arg, size);
1408 }
1409
1410 static void
1411 volume_label_coder (struct tar_stat_info const *st, char const *keyword,
1412                     struct xheader *xhdr, void const *data)
1413 {
1414   code_string (data, keyword, xhdr);
1415 }
1416
1417 static void
1418 volume_label_decoder (struct tar_stat_info *st,
1419                       char const *keyword __attribute__((unused)),
1420                       char const *arg,
1421                       size_t size __attribute__((unused)))
1422 {
1423   decode_string (&volume_label, arg);
1424 }
1425
1426 static void
1427 volume_size_coder (struct tar_stat_info const *st, char const *keyword,
1428                    struct xheader *xhdr, void const *data)
1429 {
1430   off_t const *v = data;
1431   code_num (*v, keyword, xhdr);
1432 }
1433
1434 static void
1435 volume_size_decoder (struct tar_stat_info *st,
1436                      char const *keyword,
1437                      char const *arg, size_t size)
1438 {
1439   uintmax_t u;
1440   if (decode_num (&u, arg, TYPE_MAXIMUM (uintmax_t), keyword))
1441     continued_file_size = u;
1442 }
1443
1444 /* FIXME: Merge with volume_size_coder */
1445 static void
1446 volume_offset_coder (struct tar_stat_info const *st, char const *keyword,
1447                      struct xheader *xhdr, void const *data)
1448 {
1449   off_t const *v = data;
1450   code_num (*v, keyword, xhdr);
1451 }
1452
1453 static void
1454 volume_offset_decoder (struct tar_stat_info *st,
1455                        char const *keyword,
1456                        char const *arg, size_t size)
1457 {
1458   uintmax_t u;
1459   if (decode_num (&u, arg, TYPE_MAXIMUM (uintmax_t), keyword))
1460     continued_file_offset = u;
1461 }
1462
1463 static void
1464 volume_filename_decoder (struct tar_stat_info *st,
1465                          char const *keyword __attribute__((unused)),
1466                          char const *arg,
1467                          size_t size __attribute__((unused)))
1468 {
1469   decode_string (&continued_file_name, arg);
1470 }
1471
1472 static void
1473 sparse_major_coder (struct tar_stat_info const *st, char const *keyword,
1474                     struct xheader *xhdr, void const *data)
1475 {
1476   code_num (st->sparse_major, keyword, xhdr);
1477 }
1478
1479 static void
1480 sparse_major_decoder (struct tar_stat_info *st,
1481                       char const *keyword,
1482                       char const *arg,
1483                       size_t size)
1484 {
1485   uintmax_t u;
1486   if (decode_num (&u, arg, TYPE_MAXIMUM (unsigned), keyword))
1487     st->sparse_major = u;
1488 }
1489
1490 static void
1491 sparse_minor_coder (struct tar_stat_info const *st, char const *keyword,
1492                       struct xheader *xhdr, void const *data)
1493 {
1494   code_num (st->sparse_minor, keyword, xhdr);
1495 }
1496
1497 static void
1498 sparse_minor_decoder (struct tar_stat_info *st,
1499                       char const *keyword,
1500                       char const *arg,
1501                       size_t size)
1502 {
1503   uintmax_t u;
1504   if (decode_num (&u, arg, TYPE_MAXIMUM (unsigned), keyword))
1505     st->sparse_minor = u;
1506 }
1507
1508 struct xhdr_tab const xhdr_tab[] = {
1509   { "atime",    atime_coder,    atime_decoder,    0 },
1510   { "comment",  dummy_coder,    dummy_decoder,    0 },
1511   { "charset",  dummy_coder,    dummy_decoder,    0 },
1512   { "ctime",    ctime_coder,    ctime_decoder,    0 },
1513   { "gid",      gid_coder,      gid_decoder,      0 },
1514   { "gname",    gname_coder,    gname_decoder,    0 },
1515   { "linkpath", linkpath_coder, linkpath_decoder, 0 },
1516   { "mtime",    mtime_coder,    mtime_decoder,    0 },
1517   { "path",     path_coder,     path_decoder,     0 },
1518   { "size",     size_coder,     size_decoder,     0 },
1519   { "uid",      uid_coder,      uid_decoder,      0 },
1520   { "uname",    uname_coder,    uname_decoder,    0 },
1521
1522   /* Sparse file handling */
1523   { "GNU.sparse.name",       path_coder, path_decoder,
1524     XHDR_PROTECTED },
1525   { "GNU.sparse.major",      sparse_major_coder, sparse_major_decoder,
1526     XHDR_PROTECTED },
1527   { "GNU.sparse.minor",      sparse_minor_coder, sparse_minor_decoder,
1528     XHDR_PROTECTED },
1529   { "GNU.sparse.realsize",   sparse_size_coder, sparse_size_decoder,
1530     XHDR_PROTECTED },
1531   { "GNU.sparse.numblocks",  sparse_numblocks_coder, sparse_numblocks_decoder,
1532     XHDR_PROTECTED },
1533
1534   /* tar 1.14 - 1.15.90 keywords. */
1535   { "GNU.sparse.size",       sparse_size_coder, sparse_size_decoder,
1536     XHDR_PROTECTED },
1537   /* tar 1.14 - 1.15.1 keywords. Multiple instances of these appeared in 'x'
1538      headers, and each of them was meaningful. It confilcted with POSIX specs,
1539      which requires that "when extended header records conflict, the last one
1540      given in the header shall take precedence." */
1541   { "GNU.sparse.offset",     sparse_offset_coder, sparse_offset_decoder,
1542     XHDR_PROTECTED },
1543   { "GNU.sparse.numbytes",   sparse_numbytes_coder, sparse_numbytes_decoder,
1544     XHDR_PROTECTED },
1545   /* tar 1.15.90 keyword, introduced to remove the above-mentioned conflict. */
1546   { "GNU.sparse.map",        NULL /* Unused, see pax_dump_header() */,
1547     sparse_map_decoder, 0 },
1548
1549   { "GNU.dumpdir",           dumpdir_coder, dumpdir_decoder,
1550     XHDR_PROTECTED },
1551
1552   /* Keeps the tape/volume label. May be present only in the global headers.
1553      Equivalent to GNUTYPE_VOLHDR.  */
1554   { "GNU.volume.label", volume_label_coder, volume_label_decoder,
1555     XHDR_PROTECTED | XHDR_GLOBAL },
1556
1557   /* These may be present in a first global header of the archive.
1558      They provide the same functionality as GNUTYPE_MULTIVOL header.
1559      The GNU.volume.size keeps the real_s_sizeleft value, which is
1560      otherwise kept in the size field of a multivolume header.  The
1561      GNU.volume.offset keeps the offset of the start of this volume,
1562      otherwise kept in oldgnu_header.offset.  */
1563   { "GNU.volume.filename", volume_label_coder, volume_filename_decoder,
1564     XHDR_PROTECTED | XHDR_GLOBAL },
1565   { "GNU.volume.size", volume_size_coder, volume_size_decoder,
1566     XHDR_PROTECTED | XHDR_GLOBAL },
1567   { "GNU.volume.offset", volume_offset_coder, volume_offset_decoder,
1568     XHDR_PROTECTED | XHDR_GLOBAL },
1569
1570   { NULL, NULL, NULL, 0 }
1571 };