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

   1 /* POSIX extended and STAR headers.
   2
   3    Copyright (C) 2003 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    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 #include "system.h"
  20
  21 #include <grp.h>
  22 #include <hash.h>
  23 #include <pwd.h>
  24 #include <quotearg.h>
  25
  26 #include "common.h"
  27
  28 #define obstack_chunk_alloc xmalloc
  29 #define obstack_chunk_free free
  30 #include <obstack.h>
  31
  32 /* General Interface */
  33
  34 struct xhdr_tab
  35 {
  36   char const *keyword;
  37   void (*coder) (struct tar_stat_info const *, char const *, struct xheader *);
  38   void (*decoder) (struct tar_stat_info *, char const *);
  39 };
  40
  41 static struct xhdr_tab const xhdr_tab[];
  42
  43 static struct xhdr_tab const *
  44 locate_handler (char const *keyword)
  45 {
  46   struct xhdr_tab const *p;
  47
  48   for (p = xhdr_tab; p->keyword; p++)
  49     if (strcmp (p->keyword, keyword) == 0)
  50       return p;
  51   return NULL;
  52 }
  53
  54 /* Decodes a single extended header record. Advances P to the next
  55    record.
  56    Returns true on success, false otherwise. */
  57 static bool
  58 decode_record (char **p, struct tar_stat_info *st)
  59 {
  60   size_t len;
  61   char const *keyword;
  62   char *eqp;
  63   char *start = *p;
  64   struct xhdr_tab const *t;
  65
  66   if (**p == 0)
  67     return false;
  68
  69   len = strtoul (*p, p, 10);
  70   if (**p != ' ')
  71     {
  72       ERROR ((0, 0, _("Malformed extended header: missing whitespace after the length")));
  73       return false;
  74     }
  75
  76   keyword = ++*p;
  77   for (;*p < start + len; ++*p)
  78     if (**p == '=')
  79       break;
  80
  81   if (**p != '=')
  82     {
  83       ERROR ((0, 0, _("Malformed extended header: missing equal sign")));
  84       return false;
  85     }
  86
  87   eqp = *p;
  88   **p = 0;
  89   t = locate_handler (keyword);
  90   if (t)
  91     {
  92       char endc;
  93       char *value;
  94
  95       value = ++*p;
  96
  97       endc = start[len-1];
  98       start[len-1] = 0;
  99       t->decoder (st, value);
 100       start[len-1] = endc;
 101     }
 102   *eqp = '=';
 103   *p = &start[len];
 104   return true;
 105 }
 106
 107 void
 108 xheader_decode (struct tar_stat_info *st)
 109 {
 110   char *p = extended_header.buffer;
 111   char *endp = &extended_header.buffer[extended_header.size-1];
 112
 113   while (p < endp)
 114     if (!decode_record (&p, st))
 115       break;
 116 }
 117
 118 void
 119 xheader_store (char const *keyword, struct tar_stat_info const *st)
 120 {
 121   struct xhdr_tab const *t;
 122
 123   if (extended_header.buffer)
 124     return;
 125   t = locate_handler (keyword);
 126   if (!t)
 127     return;
 128   if (!extended_header.stk)
 129     {
 130       extended_header.stk = xmalloc (sizeof *extended_header.stk);
 131       obstack_init (extended_header.stk);
 132     }
 133   t->coder (st, keyword, &extended_header);
 134 }
 135
 136 void
 137 xheader_read (union block *p, size_t size)
 138 {
 139   size_t i, j;
 140   size_t nblocks;
 141
 142   free (extended_header.buffer);
 143   extended_header.size = size;
 144   nblocks = (size + BLOCKSIZE - 1) / BLOCKSIZE;
 145   extended_header.buffer = xmalloc (size + 1);
 146
 147   set_next_block_after (p);
 148   for (i = j = 0; i < nblocks; i++)
 149     {
 150       size_t len;
 151
 152       p = find_next_block ();
 153       len = size;
 154       if (len > BLOCKSIZE)
 155         len = BLOCKSIZE;
 156       memcpy (&extended_header.buffer[j], p->buffer, len);
 157       set_next_block_after (p);
 158
 159       j += len;
 160       size -= len;
 161     }
 162 }
 163
 164 static size_t
 165 format_uintmax (uintmax_t val, char *buf, size_t s)
 166 {
 167   if (!buf)
 168     {
 169       s = 0;
 170       do
 171         s++;
 172       while ((val /= 10) != 0);
 173     }
 174   else
 175     {
 176       char *p = buf + s - 1;
 177
 178       do
 179         {
 180           *p-- = val % 10 + '0';
 181         }
 182       while ((val /= 10) != 0);
 183
 184       while (p >= buf)
 185         *p-- = '0';
 186     }
 187   return s;
 188 }
 189
 190 static void
 191 xheader_print (struct xheader *xhdr, char const *keyword, char const *value)
 192 {
 193   size_t len = strlen (keyword) + strlen (value) + 3; /* ' ' + '=' + '\n' */
 194   size_t p, n = 0;
 195   char nbuf[100];
 196
 197   do
 198     {
 199       p = n;
 200       n = format_uintmax (len + p, NULL, 0);
 201     }
 202   while (n != p);
 203
 204   format_uintmax (len + n, nbuf, n);
 205   obstack_grow (xhdr->stk, nbuf, n);
 206   obstack_1grow (xhdr->stk, ' ');
 207   obstack_grow (xhdr->stk, keyword, strlen (keyword));
 208   obstack_1grow (xhdr->stk, '=');
 209   obstack_grow (xhdr->stk, value, strlen (value));
 210   obstack_1grow (xhdr->stk, '\n');
 211 }
 212
 213 void
 214 xheader_finish (struct xheader *xhdr)
 215 {
 216   obstack_1grow (xhdr->stk, 0);
 217   xhdr->buffer = obstack_finish (xhdr->stk);
 218   xhdr->size = strlen (xhdr->buffer);
 219 }
 220
 221 void
 222 xheader_destroy (struct xheader *xhdr)
 223 {
 224   if (xhdr->stk)
 225     {
 226       obstack_free (xhdr->stk, NULL);
 227       free (xhdr->stk);
 228       xhdr->stk = NULL;
 229     }
 230   else
 231     free (xhdr->buffer);
 232   xhdr->buffer = 0;
 233   xhdr->size = 0;
 234 }
 235
 236 \f
 237 /* Implementations */
 238 static void
 239 code_string (char const *string, char const *keyword, struct xheader *xhdr)
 240 {
 241   xheader_print (xhdr, keyword, string);
 242 }
 243
 244 static void
 245 code_time (time_t t, char const *keyword, struct xheader *xhdr)
 246 {
 247   char sbuf[100];
 248   size_t s = format_uintmax (t, NULL, 0);
 249   format_uintmax (t, sbuf, s);
 250   sbuf[s++] = '.';
 251   format_uintmax (0, sbuf + s, 9);
 252   sbuf[s+9] = 0;
 253   xheader_print (xhdr, keyword, sbuf);
 254 }
 255
 256 static void
 257 code_num (uintmax_t value, char const *keyword, struct xheader *xhdr)
 258 {
 259   char sbuf[100];
 260   size_t s = format_uintmax (value, NULL, 0);
 261   format_uintmax (value, sbuf, s);
 262   sbuf[s] = 0;
 263   xheader_print (xhdr, keyword, sbuf);
 264 }
 265
 266 static void
 267 dummy_coder (struct tar_stat_info const *st, char const *keyword,
 268              struct xheader *xhdr)
 269 {
 270 }
 271
 272 static void
 273 dummy_decoder (struct tar_stat_info *st, char const *arg)
 274 {
 275 }
 276
 277 static void
 278 atime_coder (struct tar_stat_info const *st, char const *keyword,
 279              struct xheader *xhdr)
 280 {
 281   code_time (st->stat.st_atime, keyword, xhdr);
 282 }
 283
 284 static void
 285 atime_decoder (struct tar_stat_info *st, char const *arg)
 286 {
 287   st->stat.st_atime = strtoul (arg, NULL, 0);
 288 }
 289
 290 static void
 291 gid_coder (struct tar_stat_info const *st, char const *keyword,
 292            struct xheader *xhdr)
 293 {
 294   code_num (st->stat.st_gid, keyword, xhdr);
 295 }
 296
 297 static void
 298 gid_decoder (struct tar_stat_info *st, char const *arg)
 299 {
 300   st->stat.st_gid = strtoul (arg, NULL, 0);
 301 }
 302
 303 static void
 304 gname_coder (struct tar_stat_info const *st, char const *keyword,
 305              struct xheader *xhdr)
 306 {
 307   code_string (st->gname, keyword, xhdr);
 308 }
 309
 310 static void
 311 gname_decoder (struct tar_stat_info *st, char const *arg)
 312 {
 313   assign_string (&st->gname, arg);
 314 }
 315
 316 static void
 317 linkpath_coder (struct tar_stat_info const *st, char const *keyword,
 318                 struct xheader *xhdr)
 319 {
 320   code_string (st->link_name, keyword, xhdr);
 321 }
 322
 323 static void
 324 linkpath_decoder (struct tar_stat_info *st, char const *arg)
 325 {
 326   assign_string (&st->link_name, arg);
 327 }
 328
 329 static void
 330 ctime_coder (struct tar_stat_info const *st, char const *keyword,
 331              struct xheader *xhdr)
 332 {
 333   code_time (st->stat.st_ctime, keyword, xhdr);
 334 }
 335
 336 static void
 337 ctime_decoder (struct tar_stat_info *st, char const *arg)
 338 {
 339   st->stat.st_ctime = strtoul (arg, NULL, 0);
 340 }
 341
 342 static void
 343 mtime_coder (struct tar_stat_info const *st, char const *keyword,
 344              struct xheader *xhdr)
 345 {
 346   code_time (st->stat.st_mtime, keyword, xhdr);
 347 }
 348
 349 static void
 350 mtime_decoder (struct tar_stat_info *st, char const *arg)
 351 {
 352   st->stat.st_mtime = strtoul (arg, NULL, 0);
 353 }
 354
 355 static void
 356 path_coder (struct tar_stat_info const *st, char const *keyword,
 357             struct xheader *xhdr)
 358 {
 359   code_string (st->file_name, keyword, xhdr);
 360 }
 361
 362 static void
 363 path_decoder (struct tar_stat_info *st, char const *arg)
 364 {
 365   assign_string (&st->orig_file_name, arg);
 366   assign_string (&st->file_name, arg);
 367   st->had_trailing_slash = strip_trailing_slashes (st->file_name);
 368 }
 369
 370 static void
 371 size_coder (struct tar_stat_info const *st, char const *keyword,
 372             struct xheader *xhdr)
 373 {
 374   code_num (st->stat.st_size, keyword, xhdr);
 375 }
 376
 377 static void
 378 size_decoder (struct tar_stat_info *st, char const *arg)
 379 {
 380   st->stat.st_size = strtoul (arg, NULL, 0);
 381 }
 382
 383 static void
 384 uid_coder (struct tar_stat_info const *st, char const *keyword,
 385            struct xheader *xhdr)
 386 {
 387   code_num (st->stat.st_uid, keyword, xhdr);
 388 }
 389
 390 static void
 391 uid_decoder (struct tar_stat_info *st, char const *arg)
 392 {
 393   st->stat.st_uid = strtoul (arg, NULL, 0);
 394 }
 395
 396 static void
 397 uname_coder (struct tar_stat_info const *st, char const *keyword,
 398              struct xheader *xhdr)
 399 {
 400   code_string (st->uname, keyword, xhdr);
 401 }
 402
 403 static void
 404 uname_decoder (struct tar_stat_info *st, char const *arg)
 405 {
 406   assign_string (&st->uname, arg);
 407 }
 408
 409 static struct xhdr_tab const xhdr_tab[] = {
 410   { "atime",    atime_coder,    atime_decoder   },
 411   { "comment",  dummy_coder,    dummy_decoder   },
 412   { "charset",  dummy_coder,    dummy_decoder   },
 413   { "ctime",    ctime_coder,    ctime_decoder   },
 414   { "gid",      gid_coder,      gid_decoder     },
 415   { "gname",    gname_coder,    gname_decoder   },
 416   { "linkpath", linkpath_coder, linkpath_decoder},
 417   { "mtime",    mtime_coder,    mtime_decoder   },
 418   { "path",     path_coder,     path_decoder    },
 419   { "size",     size_coder,     size_decoder    },
 420   { "uid",      uid_coder,      uid_decoder     },
 421   { "uname",    uname_coder,    uname_decoder   },
 422
 423 #if 0 /* GNU private keywords (not yet implemented) */
 424   /* Sparse file handling */
 425   { "GNU.sparse.offset",     sparse_offset_coder, sparse_offset_decoder },
 426   { "GNU.sparse.numbytes",   sparse_numbytes_coder, sparse_numbytes_decoder },
 427
 428   /* The next directory entry actually contains the names of files
 429      that were in the directory at the time the dump was made.
 430      Supersedes GNUTYPE_DUMPDIR header type.  */
 431   { "GNU.dumpdir",  dumpdir_coder, dumpdir_decoder },
 432
 433   /* Keeps the tape/volume header. May be present only in the global headers.
 434      Equivalent to GNUTYPE_VOLHDR.  */
 435   { "GNU.volume.header", volume_header_coder, volume_header_decoder },
 436
 437   /* These may be present in a first global header of the archive.
 438      They provide the same functionality as GNUTYPE_MULTIVOL header.
 439      The GNU.volume.size keeps the real_s_sizeleft value, which is
 440      otherwise kept in the size field of a multivolume header.  The
 441      GNU.volume.offset keeps the offset of the start of this volume,
 442      otherwise kept in oldgnu_header.offset.  */
 443   { "GNU.volume.size", volume_size_coder, volume_size_decoder },
 444   { "GNU.volume.offset", volume_offset_coder, volume_offset_decoder },
 445 #endif
 446
 447   { NULL, NULL, NULL }
 448 };