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

   1 /* POSIX extended headers for tar.
   2
   3    Copyright (C) 2003, 2004, 2005 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 2, 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, write to the Free Software Foundation, Inc.,
  17    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  18
  19 #include <system.h>
  20
  21 #include <fnmatch.h>
  22 #include <hash.h>
  23 #include <inttostr.h>
  24 #include <quotearg.h>
  25 #include <stpcpy.h>
  26
  27 #include "common.h"
  28
  29 #include <fnmatch.h>
  30
  31 #if !HAVE_DECL_STRTOIMAX && !defined strtoimax
  32 intmax_t strtoimax ();
  33 #endif
  34 #if !HAVE_DECL_STRTOUMAX && !defined strtoumax
  35 uintmax_t strtoumax ();
  36 #endif
  37
  38 static bool xheader_protected_pattern_p (char const *pattern);
  39 static bool xheader_protected_keyword_p (char const *keyword);
  40 static void xheader_set_single_keyword (char *) __attribute__ ((noreturn));
  41
  42 /* Used by xheader_finish() */
  43 static void code_string (char const *string, char const *keyword,
  44                          struct xheader *xhdr);
  45 static void extended_header_init (void);
  46
  47 /* Number of global headers written so far. */
  48 static size_t global_header_count;
  49 /* FIXME: Possibly it should be reset after changing the volume.
  50    POSIX %n specification says that it is expanded to the sequence
  51    number of current global header in *the* archive. However, for
  52    multi-volume archives this will yield duplicate header names
  53    in different volumes, which I'd like to avoid. The best way
  54    to solve this would be to use per-archive header count as required
  55    by POSIX *and* set globexthdr.name to, say,
  56    $TMPDIR/GlobalHead.%p.$NUMVOLUME.%n.
  57
  58    However it should wait until buffer.c is finally rewritten */
  59
  60 enum { BILLION = 1000000000, LOG10_BILLION = 9 };
  61
  62 \f
  63 /* Keyword options */
  64
  65 struct keyword_list
  66 {
  67   struct keyword_list *next;
  68   char *pattern;
  69   char *value;
  70 };
  71
  72
  73 /* List of keyword patterns set by delete= option */
  74 static struct keyword_list *keyword_pattern_list;
  75
  76 /* List of keyword/value pairs set by `keyword=value' option */
  77 static struct keyword_list *keyword_global_override_list;
  78
  79 /* List of keyword/value pairs set by `keyword:=value' option */
  80 static struct keyword_list *keyword_override_list;
  81
  82 /* List of keyword/value pairs decoded from the last 'g' type header */
  83 static struct keyword_list *global_header_override_list;
  84
  85 /* Template for the name field of an 'x' type header */
  86 static char *exthdr_name;
  87
  88 /* Template for the name field of a 'g' type header */
  89 static char *globexthdr_name;
  90
  91 static bool
  92 xheader_keyword_deleted_p (const char *kw)
  93 {
  94   struct keyword_list *kp;
  95
  96   for (kp = keyword_pattern_list; kp; kp = kp->next)
  97     if (fnmatch (kp->pattern, kw, 0) == 0)
  98       return true;
  99   return false;
 100 }
 101
 102 static bool
 103 xheader_keyword_override_p (const char *keyword)
 104 {
 105   struct keyword_list *kp;
 106
 107   for (kp = keyword_override_list; kp; kp = kp->next)
 108     if (strcmp (kp->pattern, keyword) == 0)
 109       return true;
 110   return false;
 111 }
 112
 113 static void
 114 xheader_list_append (struct keyword_list **root, char const *kw,
 115                      char const *value)
 116 {
 117   struct keyword_list *kp = xmalloc (sizeof *kp);
 118   kp->pattern = xstrdup (kw);
 119   kp->value = value ? xstrdup (value) : NULL;
 120   kp->next = *root;
 121   *root = kp;
 122 }
 123
 124 static void
 125 xheader_list_destroy (struct keyword_list **root)
 126 {
 127   if (root)
 128     {
 129       struct keyword_list *kw = *root;
 130       while (kw)
 131         {
 132           struct keyword_list *next = kw->next;
 133           free (kw->pattern);
 134           free (kw->value);
 135           free (kw);
 136           kw = next;
 137         }
 138       *root = NULL;
 139     }
 140 }
 141
 142 static void
 143 xheader_set_single_keyword (char *kw)
 144 {
 145   USAGE_ERROR ((0, 0, _("Keyword %s is unknown or not yet imlemented"), kw));
 146 }
 147
 148 static void
 149 xheader_set_keyword_equal (char *kw, char *eq)
 150 {
 151   bool global = true;
 152   char *p = eq;
 153
 154   if (eq[-1] == ':')
 155     {
 156       p--;
 157       global = false;
 158     }
 159
 160   while (p > kw && isspace (*p))
 161     p--;
 162
 163   *p = 0;
 164
 165   for (p = eq + 1; *p && isspace (*p); p++)
 166     ;
 167
 168   if (strcmp (kw, "delete") == 0)
 169     {
 170       if (xheader_protected_pattern_p (p))
 171         USAGE_ERROR ((0, 0, _("Pattern %s cannot be used"), quote (p)));
 172       xheader_list_append (&keyword_pattern_list, p, NULL);
 173     }
 174   else if (strcmp (kw, "exthdr.name") == 0)
 175     assign_string (&exthdr_name, p);
 176   else if (strcmp (kw, "globexthdr.name") == 0)
 177     assign_string (&globexthdr_name, p);
 178   else
 179     {
 180       if (xheader_protected_keyword_p (kw))
 181         USAGE_ERROR ((0, 0, _("Keyword %s cannot be overridden"), kw));
 182       if (global)
 183         xheader_list_append (&keyword_global_override_list, kw, p);
 184       else
 185         xheader_list_append (&keyword_override_list, kw, p);
 186     }
 187 }
 188
 189 void
 190 xheader_set_option (char *string)
 191 {
 192   char *token;
 193   for (token = strtok (string, ","); token; token = strtok (NULL, ","))
 194     {
 195       char *p = strchr (token, '=');
 196       if (!p)
 197         xheader_set_single_keyword (token);
 198       else
 199         xheader_set_keyword_equal (token, p);
 200     }
 201 }
 202
 203 /*
 204     string Includes:          Replaced By:
 205      %d                       The directory name of the file,
 206                               equivalent to the result of the
 207                               dirname utility on the translated
 208                               file name.
 209      %f                       The filename of the file, equivalent
 210                               to the result of the basename
 211                               utility on the translated file name.
 212      %p                       The process ID of the pax process.
 213      %%                       A '%' character. */
 214
 215 static char *
 216 xheader_format_name (struct tar_stat_info *st, const char *fmt, bool allow_n)
 217 {
 218   char *buf;
 219   size_t len = strlen (fmt);
 220   char *q;
 221   const char *p;
 222   char *dir = NULL;
 223   char *base = NULL;
 224   char pidbuf[UINTMAX_STRSIZE_BOUND];
 225   char const *pptr;
 226   char nbuf[UINTMAX_STRSIZE_BOUND];
 227   char const *nptr = NULL;
 228
 229   for (p = fmt; *p && (p = strchr (p, '%')); )
 230     {
 231       switch (p[1])
 232         {
 233         case '%':
 234           len--;
 235           break;
 236
 237         case 'd':
 238           if (st)
 239             {
 240               dir = safer_name_suffix (dir_name (st->orig_file_name),
 241                                        false, absolute_names_option);
 242               len += strlen (dir) - 1;
 243             }
 244           break;
 245
 246         case 'f':
 247           if (st)
 248             {
 249               base = base_name (st->orig_file_name);
 250               len += strlen (base) - 1;
 251             }
 252           break;
 253
 254         case 'p':
 255           pptr = umaxtostr (getpid (), pidbuf);
 256           len += pidbuf + sizeof pidbuf - 1 - pptr - 1;
 257           break;
 258
 259         case 'n':
 260           if (allow_n)
 261             {
 262               nptr = umaxtostr (global_header_count + 1, nbuf);
 263               len += nbuf + sizeof nbuf - 1 - nptr - 1;
 264             }
 265           break;
 266         }
 267       p++;
 268     }
 269
 270   buf = xmalloc (len + 1);
 271   for (q = buf, p = fmt; *p; )
 272     {
 273       if (*p == '%')
 274         {
 275           switch (p[1])
 276             {
 277             case '%':
 278               *q++ = *p++;
 279               p++;
 280               break;
 281
 282             case 'd':
 283               if (dir)
 284                 q = stpcpy (q, dir);
 285               p += 2;
 286               break;
 287
 288             case 'f':
 289               if (base)
 290                 q = stpcpy (q, base);
 291               p += 2;
 292               break;
 293
 294             case 'p':
 295               q = stpcpy (q, pptr);
 296               p += 2;
 297               break;
 298
 299             case 'n':
 300               if (nptr)
 301                 {
 302                   q = stpcpy (q, nptr);
 303                   p += 2;
 304                 }
 305               /* else fall through */
 306
 307             default:
 308               *q++ = *p++;
 309               if (*p)
 310                 *q++ = *p++;
 311             }
 312         }
 313       else
 314         *q++ = *p++;
 315     }
 316
 317   /* Do not allow it to end in a slash */
 318   while (q > buf && ISSLASH (q[-1]))
 319     q--;
 320   *q = 0;
 321   return buf;
 322 }
 323
 324 char *
 325 xheader_xhdr_name (struct tar_stat_info *st)
 326 {
 327   if (!exthdr_name)
 328     assign_string (&exthdr_name, "%d/PaxHeaders.%p/%f");
 329   return xheader_format_name (st, exthdr_name, false);
 330 }
 331
 332 #define GLOBAL_HEADER_TEMPLATE "/GlobalHead.%p.%n"
 333
 334 char *
 335 xheader_ghdr_name (void)
 336 {
 337   if (!globexthdr_name)
 338     {
 339       size_t len;
 340       const char *tmp = getenv ("TMPDIR");
 341       if (!tmp)
 342         tmp = "/tmp";
 343       len = strlen (tmp) + sizeof (GLOBAL_HEADER_TEMPLATE); /* Includes nul */
 344       globexthdr_name = xmalloc (len);
 345       strcpy(globexthdr_name, tmp);
 346       strcat(globexthdr_name, GLOBAL_HEADER_TEMPLATE);
 347     }
 348
 349   return xheader_format_name (NULL, globexthdr_name, true);
 350 }
 351
 352 void
 353 xheader_write (char type, char *name, struct xheader *xhdr)
 354 {
 355   union block *header;
 356   size_t size;
 357   char *p;
 358
 359   size = xhdr->size;
 360   header = start_private_header (name, size);
 361   header->header.typeflag = type;
 362
 363   simple_finish_header (header);
 364
 365   p = xhdr->buffer;
 366
 367   do
 368     {
 369       size_t len;
 370
 371       header = find_next_block ();
 372       len = BLOCKSIZE;
 373       if (len > size)
 374         len = size;
 375       memcpy (header->buffer, p, len);
 376       if (len < BLOCKSIZE)
 377         memset (header->buffer + len, 0, BLOCKSIZE - len);
 378       p += len;
 379       size -= len;
 380       set_next_block_after (header);
 381     }
 382   while (size > 0);
 383   xheader_destroy (xhdr);
 384 }
 385
 386 void
 387 xheader_write_global (void)
 388 {
 389   char *name;
 390   struct keyword_list *kp;
 391
 392   if (!keyword_global_override_list)
 393     return;
 394
 395   extended_header_init ();
 396   for (kp = keyword_global_override_list; kp; kp = kp->next)
 397     code_string (kp->value, kp->pattern, &extended_header);
 398   xheader_finish (&extended_header);
 399   xheader_write (XGLTYPE, name = xheader_ghdr_name (),
 400                  &extended_header);
 401   free (name);
 402   global_header_count++;
 403 }
 404
 405 \f
 406 /* General Interface */
 407
 408 struct xhdr_tab
 409 {
 410   char const *keyword;
 411   void (*coder) (struct tar_stat_info const *, char const *,
 412                  struct xheader *, void *data);
 413   void (*decoder) (struct tar_stat_info *, char const *);
 414   bool protect;
 415 };
 416
 417 /* This declaration must be extern, because ISO C99 section 6.9.2
 418    prohibits a tentative definition that has both internal linkage and
 419    incomplete type.  If we made it static, we'd have to declare its
 420    size which would be a maintenance pain; if we put its initializer
 421    here, we'd need a boatload of forward declarations, which would be
 422    even more of a pain.  */
 423 extern struct xhdr_tab const xhdr_tab[];
 424
 425 static struct xhdr_tab const *
 426 locate_handler (char const *keyword)
 427 {
 428   struct xhdr_tab const *p;
 429
 430   for (p = xhdr_tab; p->keyword; p++)
 431     if (strcmp (p->keyword, keyword) == 0)
 432       return p;
 433   return NULL;
 434 }
 435
 436 static bool
 437 xheader_protected_pattern_p (const char *pattern)
 438 {
 439   struct xhdr_tab const *p;
 440
 441   for (p = xhdr_tab; p->keyword; p++)
 442     if (p->protect && fnmatch (pattern, p->keyword, 0) == 0)
 443       return true;
 444   return false;
 445 }
 446
 447 static bool
 448 xheader_protected_keyword_p (const char *keyword)
 449 {
 450   struct xhdr_tab const *p;
 451
 452   for (p = xhdr_tab; p->keyword; p++)
 453     if (p->protect && strcmp (p->keyword, keyword) == 0)
 454       return true;
 455   return false;
 456 }
 457
 458 /* Decode a single extended header record, advancing *PTR to the next record.
 459    Return true on success, false otherwise.  */
 460 static bool
 461 decode_record (char **ptr,
 462                void (*handler) (void *, char const *, char const *),
 463                void *data)
 464 {
 465   char *start = *ptr;
 466   char *p = start;
 467   unsigned long int len;
 468   char *len_lim;
 469   char const *keyword;
 470   char *nextp;
 471   size_t len_max = extended_header.buffer + extended_header.size - start;
 472
 473   while (*p == ' ' || *p == '\t')
 474     p++;
 475
 476   if (! ISDIGIT (*p))
 477     {
 478       if (*p)
 479         ERROR ((0, 0, _("Malformed extended header: missing length")));
 480       return false;
 481     }
 482
 483   errno = 0;
 484   len = strtoul (p, &len_lim, 10);
 485
 486   if (len_max < len)
 487     {
 488       int len_len = len_lim - p;
 489       ERROR ((0, 0, _("Extended header length %*s is out of range"),
 490               len_len, p));
 491       return false;
 492     }
 493
 494   nextp = start + len;
 495
 496   for (p = len_lim; *p == ' ' || *p == '\t'; p++)
 497     continue;
 498   if (p == len_lim)
 499     {
 500       ERROR ((0, 0,
 501               _("Malformed extended header: missing blank after length")));
 502       return false;
 503     }
 504
 505   keyword = p;
 506   p = strchr (p, '=');
 507   if (! (p && p < nextp))
 508     {
 509       ERROR ((0, 0, _("Malformed extended header: missing equal sign")));
 510       return false;
 511     }
 512
 513   if (nextp[-1] != '\n')
 514     {
 515       ERROR ((0, 0, _("Malformed extended header: missing newline")));
 516       return false;
 517     }
 518
 519   *p = nextp[-1] = '\0';
 520   handler (data, keyword, p + 1);
 521   *p = '=';
 522   nextp[-1] = '\n';
 523   *ptr = nextp;
 524   return true;
 525 }
 526
 527 static void
 528 run_override_list (struct keyword_list *kp, struct tar_stat_info *st)
 529 {
 530   for (; kp; kp = kp->next)
 531     {
 532       struct xhdr_tab const *t = locate_handler (kp->pattern);
 533       if (t)
 534         t->decoder (st, kp->value);
 535     }
 536 }
 537
 538 static void
 539 decx (void *data, char const *keyword, char const *value)
 540 {
 541   struct xhdr_tab const *t;
 542   struct tar_stat_info *st = data;
 543
 544   if (xheader_keyword_deleted_p (keyword)
 545       || xheader_keyword_override_p (keyword))
 546     return;
 547
 548   t = locate_handler (keyword);
 549   if (t)
 550     t->decoder (st, value);
 551 }
 552
 553 void
 554 xheader_decode (struct tar_stat_info *st)
 555 {
 556   run_override_list (keyword_global_override_list, st);
 557   run_override_list (global_header_override_list, st);
 558
 559   if (extended_header.size)
 560     {
 561       char *p = extended_header.buffer + BLOCKSIZE;
 562       while (decode_record (&p, decx, st))
 563         continue;
 564     }
 565   run_override_list (keyword_override_list, st);
 566 }
 567
 568 static void
 569 decg (void *data, char const *keyword, char const *value)
 570 {
 571   struct keyword_list **kwl = data;
 572   xheader_list_append (kwl, keyword, value);
 573 }
 574
 575 void
 576 xheader_decode_global (void)
 577 {
 578   if (extended_header.size)
 579     {
 580       char *p = extended_header.buffer + BLOCKSIZE;
 581
 582       xheader_list_destroy (&global_header_override_list);
 583       while (decode_record (&p, decg, &global_header_override_list))
 584         continue;
 585     }
 586 }
 587
 588 static void
 589 extended_header_init (void)
 590 {
 591   if (!extended_header.stk)
 592     {
 593       extended_header.stk = xmalloc (sizeof *extended_header.stk);
 594       obstack_init (extended_header.stk);
 595     }
 596 }
 597
 598 void
 599 xheader_store (char const *keyword, struct tar_stat_info const *st, void *data)
 600 {
 601   struct xhdr_tab const *t;
 602
 603   if (extended_header.buffer)
 604     return;
 605   t = locate_handler (keyword);
 606   if (!t)
 607     return;
 608   if (xheader_keyword_deleted_p (keyword)
 609       || xheader_keyword_override_p (keyword))
 610     return;
 611   extended_header_init ();
 612   t->coder (st, keyword, &extended_header, data);
 613 }
 614
 615 void
 616 xheader_read (union block *p, size_t size)
 617 {
 618   size_t j = 0;
 619   size_t nblocks;
 620
 621   free (extended_header.buffer);
 622   size += BLOCKSIZE;
 623   extended_header.size = size;
 624   nblocks = (size + BLOCKSIZE - 1) / BLOCKSIZE;
 625   extended_header.buffer = xmalloc (size + 1);
 626   extended_header.buffer[size] = '\0';
 627
 628   do
 629     {
 630       size_t len = size;
 631
 632       if (len > BLOCKSIZE)
 633         len = BLOCKSIZE;
 634
 635       memcpy (&extended_header.buffer[j], p->buffer, len);
 636       set_next_block_after (p);
 637
 638       p = find_next_block ();
 639
 640       j += len;
 641       size -= len;
 642     }
 643   while (size > 0);
 644 }
 645
 646 static void
 647 xheader_print (struct xheader *xhdr, char const *keyword, char const *value)
 648 {
 649   size_t len = strlen (keyword) + strlen (value) + 3; /* ' ' + '=' + '\n' */
 650   size_t p;
 651   size_t n = 0;
 652   char nbuf[UINTMAX_STRSIZE_BOUND];
 653   char const *np;
 654
 655   do
 656     {
 657       p = n;
 658       np = umaxtostr (len + p, nbuf);
 659       n = nbuf + sizeof nbuf - 1 - np;
 660     }
 661   while (n != p);
 662
 663   obstack_grow (xhdr->stk, np, n);
 664   obstack_1grow (xhdr->stk, ' ');
 665   obstack_grow (xhdr->stk, keyword, strlen (keyword));
 666   obstack_1grow (xhdr->stk, '=');
 667   obstack_grow (xhdr->stk, value, strlen (value));
 668   obstack_1grow (xhdr->stk, '\n');
 669 }
 670
 671 void
 672 xheader_finish (struct xheader *xhdr)
 673 {
 674   struct keyword_list *kp;
 675
 676   for (kp = keyword_override_list; kp; kp = kp->next)
 677     code_string (kp->value, kp->pattern, xhdr);
 678
 679   obstack_1grow (xhdr->stk, 0);
 680   xhdr->buffer = obstack_finish (xhdr->stk);
 681   xhdr->size = strlen (xhdr->buffer);
 682 }
 683
 684 void
 685 xheader_destroy (struct xheader *xhdr)
 686 {
 687   if (xhdr->stk)
 688     {
 689       obstack_free (xhdr->stk, NULL);
 690       free (xhdr->stk);
 691       xhdr->stk = NULL;
 692     }
 693   else
 694     free (xhdr->buffer);
 695   xhdr->buffer = 0;
 696   xhdr->size = 0;
 697 }
 698
 699 \f
 700 /* Implementations */
 701
 702 static void
 703 out_of_range_header (char const *keyword, char const *value,
 704                      uintmax_t minus_minval, uintmax_t maxval)
 705 {
 706   char minval_buf[UINTMAX_STRSIZE_BOUND + 1];
 707   char maxval_buf[UINTMAX_STRSIZE_BOUND];
 708   char *minval_string = umaxtostr (minus_minval, minval_buf + 1);
 709   char *maxval_string = umaxtostr (maxval, maxval_buf);
 710   if (minus_minval)
 711     *--minval_string = '-';
 712
 713   /* TRANSLATORS: The first %s is the pax extended header keyword
 714      (atime, gid, etc.).  */
 715   ERROR ((0, 0, _("Extended header %s=%s is out of range %s..%s"),
 716           keyword, value, minval_string, maxval_string));
 717 }
 718
 719 static void
 720 code_string (char const *string, char const *keyword, struct xheader *xhdr)
 721 {
 722   char *outstr;
 723   if (!utf8_convert (true, string, &outstr))
 724     {
 725       /* FIXME: report error */
 726       outstr = xstrdup (string);
 727     }
 728   xheader_print (xhdr, keyword, outstr);
 729   free (outstr);
 730 }
 731
 732 static void
 733 decode_string (char **string, char const *arg)
 734 {
 735   if (*string)
 736     {
 737       free (*string);
 738       *string = NULL;
 739     }
 740   if (!utf8_convert (false, arg, string))
 741     {
 742       /* FIXME: report error and act accordingly to --pax invalid=UTF-8 */
 743       assign_string (string, arg);
 744     }
 745 }
 746
 747 static void
 748 code_time (struct timespec t, char const *keyword, struct xheader *xhdr)
 749 {
 750   time_t s = t.tv_sec;
 751   int ns = t.tv_nsec;
 752   char sbuf[1/*"-"*/ + UINTMAX_STRSIZE_BOUND + 1/*"."*/ + LOG10_BILLION];
 753   char *np;
 754   bool negative = s < 0;
 755
 756   if (negative && ns != 0)
 757     {
 758       s++;
 759       ns = BILLION - ns;
 760     }
 761
 762   np = umaxtostr (negative ? - (uintmax_t) s : (uintmax_t) s, sbuf + 1);
 763   if (negative)
 764     *--np = '-';
 765   code_ns_fraction (ns, sbuf + UINTMAX_STRSIZE_BOUND);
 766   xheader_print (xhdr, keyword, np);
 767 }
 768
 769 static bool
 770 decode_time (struct timespec *ts, char const *arg, char const *keyword)
 771 {
 772   time_t s;
 773   unsigned long int ns = 0;
 774   char *p;
 775   char *arg_lim;
 776   bool negative = *arg == '-';
 777
 778   errno = 0;
 779
 780   if (ISDIGIT (arg[negative]))
 781     {
 782       if (negative)
 783         {
 784           intmax_t i = strtoimax (arg, &arg_lim, 10);
 785           if (TYPE_SIGNED (time_t) ? i < TYPE_MINIMUM (time_t) : i < 0)
 786             goto out_of_range;
 787           s = i;
 788         }
 789       else
 790         {
 791           uintmax_t i = strtoumax (arg, &arg_lim, 10);
 792           if (TYPE_MAXIMUM (time_t) < i)
 793             goto out_of_range;
 794           s = i;
 795         }
 796
 797       p = arg_lim;
 798
 799       if (errno == ERANGE)
 800         goto out_of_range;
 801
 802       if (*p == '.')
 803         {
 804           int digits = 0;
 805           bool trailing_nonzero = false;
 806
 807           while (ISDIGIT (*++p))
 808             if (digits < LOG10_BILLION)
 809               {
 810                 ns = 10 * ns + (*p - '0');
 811                 digits++;
 812               }
 813             else
 814               trailing_nonzero |= *p != '0';
 815
 816           while (digits++ < LOG10_BILLION)
 817             ns *= 10;
 818
 819           if (negative)
 820             {
 821               /* Convert "-1.10000000000001" to s == -2, ns == 89999999.
 822                  I.e., truncate time stamps towards minus infinity while
 823                  converting them to internal form.  */
 824               ns += trailing_nonzero;
 825               if (ns != 0)
 826                 {
 827                   if (s == TYPE_MINIMUM (time_t))
 828                     goto out_of_range;
 829                   s--;
 830                   ns = BILLION - ns;
 831                 }
 832             }
 833         }
 834
 835       if (! *p)
 836         {
 837           ts->tv_sec = s;
 838           ts->tv_nsec = ns;
 839           return true;
 840         }
 841     }
 842
 843   ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
 844           keyword, arg));
 845   return false;
 846
 847  out_of_range:
 848   out_of_range_header (keyword, arg, - (uintmax_t) TYPE_MINIMUM (time_t),
 849                        TYPE_MAXIMUM (time_t));
 850   return false;
 851 }
 852
 853 static void
 854 code_num (uintmax_t value, char const *keyword, struct xheader *xhdr)
 855 {
 856   char sbuf[UINTMAX_STRSIZE_BOUND];
 857   xheader_print (xhdr, keyword, umaxtostr (value, sbuf));
 858 }
 859
 860 static bool
 861 decode_num (uintmax_t *num, char const *arg, uintmax_t maxval,
 862             char const *keyword)
 863 {
 864   uintmax_t u;
 865   char *arg_lim;
 866
 867   if (! (ISDIGIT (*arg)
 868          && (errno = 0, u = strtoumax (arg, &arg_lim, 10), !*arg_lim)))
 869     {
 870       ERROR ((0, 0, _("Malformed extended header: invalid %s=%s"),
 871               keyword, arg));
 872       return false;
 873     }
 874
 875   if (! (u <= maxval && errno != ERANGE))
 876     {
 877       out_of_range_header (keyword, arg, 0, maxval);
 878       return false;
 879     }
 880
 881   *num = u;
 882   return true;
 883 }
 884
 885 static void
 886 dummy_coder (struct tar_stat_info const *st __attribute__ ((unused)),
 887              char const *keyword __attribute__ ((unused)),
 888              struct xheader *xhdr __attribute__ ((unused)),
 889              void *data __attribute__ ((unused)))
 890 {
 891 }
 892
 893 static void
 894 dummy_decoder (struct tar_stat_info *st __attribute__ ((unused)),
 895                char const *arg __attribute__ ((unused)))
 896 {
 897 }
 898
 899 static void
 900 atime_coder (struct tar_stat_info const *st, char const *keyword,
 901              struct xheader *xhdr, void *data __attribute__ ((unused)))
 902 {
 903   code_time (get_stat_atime (&st->stat), keyword, xhdr);
 904 }
 905
 906 static void
 907 atime_decoder (struct tar_stat_info *st, char const *arg)
 908 {
 909   struct timespec ts;
 910   if (decode_time (&ts, arg, "atime"))
 911     set_stat_atime (&st->stat, ts);
 912 }
 913
 914 static void
 915 gid_coder (struct tar_stat_info const *st, char const *keyword,
 916            struct xheader *xhdr, void *data __attribute__ ((unused)))
 917 {
 918   code_num (st->stat.st_gid, keyword, xhdr);
 919 }
 920
 921 static void
 922 gid_decoder (struct tar_stat_info *st, char const *arg)
 923 {
 924   uintmax_t u;
 925   if (decode_num (&u, arg, TYPE_MAXIMUM (gid_t), "gid"))
 926     st->stat.st_gid = u;
 927 }
 928
 929 static void
 930 gname_coder (struct tar_stat_info const *st, char const *keyword,
 931              struct xheader *xhdr, void *data __attribute__ ((unused)))
 932 {
 933   code_string (st->gname, keyword, xhdr);
 934 }
 935
 936 static void
 937 gname_decoder (struct tar_stat_info *st, char const *arg)
 938 {
 939   decode_string (&st->gname, arg);
 940 }
 941
 942 static void
 943 linkpath_coder (struct tar_stat_info const *st, char const *keyword,
 944                 struct xheader *xhdr, void *data __attribute__ ((unused)))
 945 {
 946   code_string (st->link_name, keyword, xhdr);
 947 }
 948
 949 static void
 950 linkpath_decoder (struct tar_stat_info *st, char const *arg)
 951 {
 952   decode_string (&st->link_name, arg);
 953 }
 954
 955 static void
 956 ctime_coder (struct tar_stat_info const *st, char const *keyword,
 957              struct xheader *xhdr, void *data __attribute__ ((unused)))
 958 {
 959   code_time (get_stat_ctime (&st->stat), keyword, xhdr);
 960 }
 961
 962 static void
 963 ctime_decoder (struct tar_stat_info *st, char const *arg)
 964 {
 965   struct timespec ts;
 966   if (decode_time (&ts, arg, "ctime"))
 967     set_stat_ctime (&st->stat, ts);
 968 }
 969
 970 static void
 971 mtime_coder (struct tar_stat_info const *st, char const *keyword,
 972              struct xheader *xhdr, void *data __attribute__ ((unused)))
 973 {
 974   code_time (get_stat_mtime (&st->stat), keyword, xhdr);
 975 }
 976
 977 static void
 978 mtime_decoder (struct tar_stat_info *st, char const *arg)
 979 {
 980   struct timespec ts;
 981   if (decode_time (&ts, arg, "mtime"))
 982     set_stat_mtime (&st->stat, ts);
 983 }
 984
 985 static void
 986 path_coder (struct tar_stat_info const *st, char const *keyword,
 987             struct xheader *xhdr, void *data __attribute__ ((unused)))
 988 {
 989   code_string (st->file_name, keyword, xhdr);
 990 }
 991
 992 static void
 993 path_decoder (struct tar_stat_info *st, char const *arg)
 994 {
 995   decode_string (&st->orig_file_name, arg);
 996   decode_string (&st->file_name, arg);
 997   st->had_trailing_slash = strip_trailing_slashes (st->file_name);
 998 }
 999
1000 static void
1001 size_coder (struct tar_stat_info const *st, char const *keyword,
1002             struct xheader *xhdr, void *data __attribute__ ((unused)))
1003 {
1004   code_num (st->stat.st_size, keyword, xhdr);
1005 }
1006
1007 static void
1008 size_decoder (struct tar_stat_info *st, char const *arg)
1009 {
1010   uintmax_t u;
1011   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), "size"))
1012     st->archive_file_size = st->stat.st_size = u;
1013 }
1014
1015 static void
1016 uid_coder (struct tar_stat_info const *st, char const *keyword,
1017            struct xheader *xhdr, void *data __attribute__ ((unused)))
1018 {
1019   code_num (st->stat.st_uid, keyword, xhdr);
1020 }
1021
1022 static void
1023 uid_decoder (struct tar_stat_info *st, char const *arg)
1024 {
1025   uintmax_t u;
1026   if (decode_num (&u, arg, TYPE_MAXIMUM (uid_t), "uid"))
1027     st->stat.st_uid = u;
1028 }
1029
1030 static void
1031 uname_coder (struct tar_stat_info const *st, char const *keyword,
1032              struct xheader *xhdr, void *data __attribute__ ((unused)))
1033 {
1034   code_string (st->uname, keyword, xhdr);
1035 }
1036
1037 static void
1038 uname_decoder (struct tar_stat_info *st, char const *arg)
1039 {
1040   decode_string (&st->uname, arg);
1041 }
1042
1043 static void
1044 sparse_size_coder (struct tar_stat_info const *st, char const *keyword,
1045              struct xheader *xhdr, void *data)
1046 {
1047   size_coder (st, keyword, xhdr, data);
1048 }
1049
1050 static void
1051 sparse_size_decoder (struct tar_stat_info *st, char const *arg)
1052 {
1053   uintmax_t u;
1054   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), "GNU.sparse.size"))
1055     st->stat.st_size = u;
1056 }
1057
1058 static void
1059 sparse_numblocks_coder (struct tar_stat_info const *st, char const *keyword,
1060                         struct xheader *xhdr,
1061                         void *data __attribute__ ((unused)))
1062 {
1063   code_num (st->sparse_map_avail, keyword, xhdr);
1064 }
1065
1066 static void
1067 sparse_numblocks_decoder (struct tar_stat_info *st, char const *arg)
1068 {
1069   uintmax_t u;
1070   if (decode_num (&u, arg, SIZE_MAX, "GNU.sparse.numblocks"))
1071     {
1072       st->sparse_map_size = u;
1073       st->sparse_map = xcalloc (u, sizeof st->sparse_map[0]);
1074       st->sparse_map_avail = 0;
1075     }
1076 }
1077
1078 static void
1079 sparse_offset_coder (struct tar_stat_info const *st, char const *keyword,
1080                      struct xheader *xhdr, void *data)
1081 {
1082   size_t i = *(size_t*)data;
1083   code_num (st->sparse_map[i].offset, keyword, xhdr);
1084 }
1085
1086 static void
1087 sparse_offset_decoder (struct tar_stat_info *st, char const *arg)
1088 {
1089   uintmax_t u;
1090   if (decode_num (&u, arg, TYPE_MAXIMUM (off_t), "GNU.sparse.offset"))
1091     st->sparse_map[st->sparse_map_avail].offset = u;
1092 }
1093
1094 static void
1095 sparse_numbytes_coder (struct tar_stat_info const *st, char const *keyword,
1096                      struct xheader *xhdr, void *data)
1097 {
1098   size_t i = *(size_t*)data;
1099   code_num (st->sparse_map[i].numbytes, keyword, xhdr);
1100 }
1101
1102 static void
1103 sparse_numbytes_decoder (struct tar_stat_info *st, char const *arg)
1104 {
1105   uintmax_t u;
1106   if (decode_num (&u, arg, SIZE_MAX, "GNU.sparse.numbytes"))
1107     {
1108       if (st->sparse_map_avail == st->sparse_map_size)
1109         st->sparse_map = x2nrealloc (st->sparse_map,
1110                                      &st->sparse_map_size,
1111                                      sizeof st->sparse_map[0]);
1112       st->sparse_map[st->sparse_map_avail++].numbytes = u;
1113     }
1114 }
1115
1116 struct xhdr_tab const xhdr_tab[] = {
1117   { "atime",    atime_coder,    atime_decoder,    false },
1118   { "comment",  dummy_coder,    dummy_decoder,    false },
1119   { "charset",  dummy_coder,    dummy_decoder,    false },
1120   { "ctime",    ctime_coder,    ctime_decoder,    false },
1121   { "gid",      gid_coder,      gid_decoder,      false },
1122   { "gname",    gname_coder,    gname_decoder,    false },
1123   { "linkpath", linkpath_coder, linkpath_decoder, false },
1124   { "mtime",    mtime_coder,    mtime_decoder,    false },
1125   { "path",     path_coder,     path_decoder,     false },
1126   { "size",     size_coder,     size_decoder,     false },
1127   { "uid",      uid_coder,      uid_decoder,      false },
1128   { "uname",    uname_coder,    uname_decoder,    false },
1129
1130   /* Sparse file handling */
1131   { "GNU.sparse.size",       sparse_size_coder, sparse_size_decoder, true },
1132   { "GNU.sparse.numblocks",  sparse_numblocks_coder, sparse_numblocks_decoder,
1133     true },
1134   { "GNU.sparse.offset",     sparse_offset_coder, sparse_offset_decoder,
1135     true },
1136   { "GNU.sparse.numbytes",   sparse_numbytes_coder, sparse_numbytes_decoder,
1137     true },
1138
1139 #if 0 /* GNU private keywords (not yet implemented) */
1140
1141   /* The next directory entry actually contains the names of files
1142      that were in the directory at the time the dump was made.
1143      Supersedes GNUTYPE_DUMPDIR header type.  */
1144   { "GNU.dump.name",  dump_name_coder, dump_name_decoder, false },
1145   { "GNU.dump.status", dump_status_coder, dump_status_decoder, false },
1146
1147   /* Keeps the tape/volume header. May be present only in the global headers.
1148      Equivalent to GNUTYPE_VOLHDR.  */
1149   { "GNU.volume.header", volume_header_coder, volume_header_decoder, false },
1150
1151   /* These may be present in a first global header of the archive.
1152      They provide the same functionality as GNUTYPE_MULTIVOL header.
1153      The GNU.volume.size keeps the real_s_sizeleft value, which is
1154      otherwise kept in the size field of a multivolume header.  The
1155      GNU.volume.offset keeps the offset of the start of this volume,
1156      otherwise kept in oldgnu_header.offset.  */
1157   { "GNU.volume.size", volume_size_coder, volume_size_decoder, false },
1158   { "GNU.volume.offset", volume_offset_coder, volume_offset_decoder, false },
1159 #endif
1160
1161   { NULL, NULL, NULL, false }
1162 };