bfd/compress.c

   1 /* Compressed section support (intended for debug sections).
   2    Copyright 2008, 2010
   3    Free Software Foundation, Inc.
   4
   5    This file is part of BFD, the Binary File Descriptor library.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  20    MA 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "sysdep.h"
  24 #include "bfd.h"
  25 #include "libbfd.h"
  26 #ifdef HAVE_ZLIB_H
  27 #include <zlib.h>
  28 #endif
  29
  30 #ifdef HAVE_ZLIB_H
  31 static bfd_boolean
  32 decompress_contents (bfd_byte *compressed_buffer,
  33                      bfd_size_type compressed_size,
  34                      bfd_byte *uncompressed_buffer,
  35                      bfd_size_type uncompressed_size)
  36 {
  37   z_stream strm;
  38   int rc;
  39
  40   /* It is possible the section consists of several compressed
  41      buffers concatenated together, so we uncompress in a loop.  */
  42   strm.zalloc = NULL;
  43   strm.zfree = NULL;
  44   strm.opaque = NULL;
  45   strm.avail_in = compressed_size - 12;
  46   strm.next_in = (Bytef*) compressed_buffer + 12;
  47   strm.avail_out = uncompressed_size;
  48
  49   rc = inflateInit (&strm);
  50   while (strm.avail_in > 0)
  51     {
  52       if (rc != Z_OK)
  53         return FALSE;
  54       strm.next_out = ((Bytef*) uncompressed_buffer
  55                        + (uncompressed_size - strm.avail_out));
  56       rc = inflate (&strm, Z_FINISH);
  57       if (rc != Z_STREAM_END)
  58         return FALSE;
  59       rc = inflateReset (&strm);
  60     }
  61   rc = inflateEnd (&strm);
  62   return rc == Z_OK && strm.avail_out == 0;
  63 }
  64 #endif
  65
  66 /*
  67 FUNCTION
  68         bfd_compress_section_contents
  69
  70 SYNOPSIS
  71         bfd_boolean bfd_compress_section_contents
  72           (bfd *abfd, asection *section, bfd_byte *uncompressed_buffer,
  73            bfd_size_type uncompressed_size);
  74
  75 DESCRIPTION
  76
  77         Compress data of the size specified in @var{uncompressed_size}
  78         and pointed to by @var{uncompressed_buffer} using zlib and store
  79         as the contents field.  This function assumes the contents
  80         field was allocated using bfd_malloc() or equivalent.  If zlib
  81         is not installed on this machine, the input is unmodified.
  82
  83         Return @code{TRUE} if the full section contents is compressed
  84         successfully.
  85 */
  86
  87 bfd_boolean
  88 bfd_compress_section_contents (bfd *abfd ATTRIBUTE_UNUSED,
  89                                sec_ptr sec ATTRIBUTE_UNUSED,
  90                                bfd_byte *uncompressed_buffer ATTRIBUTE_UNUSED,
  91                                bfd_size_type uncompressed_size ATTRIBUTE_UNUSED)
  92 {
  93 #ifndef HAVE_ZLIB_H
  94   bfd_set_error (bfd_error_invalid_operation);
  95   return FALSE;
  96 #else
  97   uLong compressed_size;
  98   bfd_byte *compressed_buffer;
  99
 100   compressed_size = compressBound (uncompressed_size) + 12;
 101   compressed_buffer = (bfd_byte *) bfd_malloc (compressed_size);
 102
 103   if (compressed_buffer == NULL)
 104     return FALSE;
 105
 106   if (compress ((Bytef*) compressed_buffer + 12,
 107                 &compressed_size,
 108                 (const Bytef*) uncompressed_buffer,
 109                 uncompressed_size) != Z_OK)
 110     {
 111       free (compressed_buffer);
 112       bfd_set_error (bfd_error_bad_value);
 113       return FALSE;
 114     }
 115
 116   /* Write the zlib header.  In this case, it should be "ZLIB" followed
 117      by the uncompressed section size, 8 bytes in big-endian order.  */
 118   memcpy (compressed_buffer, "ZLIB", 4);
 119   compressed_buffer[11] = uncompressed_size; uncompressed_size >>= 8;
 120   compressed_buffer[10] = uncompressed_size; uncompressed_size >>= 8;
 121   compressed_buffer[9] = uncompressed_size; uncompressed_size >>= 8;
 122   compressed_buffer[8] = uncompressed_size; uncompressed_size >>= 8;
 123   compressed_buffer[7] = uncompressed_size; uncompressed_size >>= 8;
 124   compressed_buffer[6] = uncompressed_size; uncompressed_size >>= 8;
 125   compressed_buffer[5] = uncompressed_size; uncompressed_size >>= 8;
 126   compressed_buffer[4] = uncompressed_size;
 127   compressed_size += 12;
 128
 129   /* Free the uncompressed contents if we compress in place.  */
 130   if (uncompressed_buffer == sec->contents)
 131     free (uncompressed_buffer);
 132
 133   sec->contents = compressed_buffer;
 134   sec->size = compressed_size;
 135   sec->compress_status = COMPRESS_SECTION_DONE;
 136
 137   return TRUE;
 138 #endif  /* HAVE_ZLIB_H */
 139 }
 140
 141 /*
 142 FUNCTION
 143         bfd_get_full_section_contents
 144
 145 SYNOPSIS
 146         bfd_boolean bfd_get_full_section_contents
 147           (bfd *abfd, asection *section, bfd_byte **ptr);
 148
 149 DESCRIPTION
 150         Read all data from @var{section} in BFD @var{abfd}, decompress
 151         if needed, and store in @var{*ptr}.  If @var{*ptr} is NULL,
 152         return @var{*ptr} with memory malloc'd by this function.
 153
 154         Return @code{TRUE} if the full section contents is retrieved
 155         successfully.
 156 */
 157
 158 bfd_boolean
 159 bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr)
 160 {
 161   bfd_size_type sz = sec->rawsize ? sec->rawsize : sec->size;
 162   bfd_byte *p = *ptr;
 163 #ifdef HAVE_ZLIB_H
 164   bfd_boolean ret;
 165   bfd_size_type compressed_size;
 166   bfd_size_type uncompressed_size;
 167   bfd_size_type rawsize;
 168   bfd_byte *compressed_buffer;
 169   bfd_byte *uncompressed_buffer;
 170 #endif
 171
 172   if (sz == 0)
 173     return TRUE;
 174
 175   switch (sec->compress_status)
 176     {
 177     case COMPRESS_SECTION_NONE:
 178       if (p == NULL)
 179         {
 180           p = (bfd_byte *) bfd_malloc (sz);
 181           if (p == NULL)
 182             return FALSE;
 183         }
 184       if (!bfd_get_section_contents (abfd, sec, p, 0, sz))
 185         {
 186           if (*ptr != p)
 187             free (p);
 188           return FALSE;
 189         }
 190       *ptr = p;
 191       return TRUE;
 192
 193     case DECOMPRESS_SECTION_SIZED:
 194 #ifndef HAVE_ZLIB_H
 195       bfd_set_error (bfd_error_invalid_operation);
 196       return FALSE;
 197 #else
 198       /* Read in the full compressed section contents.  */
 199       uncompressed_size = sec->size;
 200       compressed_size = sec->compressed_size;
 201       compressed_buffer = (bfd_byte *) bfd_malloc (compressed_size);
 202       if (compressed_buffer == NULL)
 203         return FALSE;
 204       rawsize = sec->rawsize;
 205       /* Clear rawsize, set size to compressed size and set compress_status
 206          to COMPRESS_SECTION_NONE.  If the compressed size is bigger than
 207          the uncompressed size, bfd_get_section_contents will fail.  */
 208       sec->rawsize = 0;
 209       sec->size = compressed_size;
 210       sec->compress_status = COMPRESS_SECTION_NONE;
 211       ret = bfd_get_section_contents (abfd, sec, compressed_buffer,
 212                                       0, compressed_size);
 213       /* Restore rawsize and size.  */
 214       sec->rawsize = rawsize;
 215       sec->size = uncompressed_size;
 216       sec->compress_status = DECOMPRESS_SECTION_SIZED;
 217       if (!ret)
 218         goto fail_compressed;
 219
 220       uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 221       if (uncompressed_buffer == NULL)
 222         goto fail_compressed;
 223
 224       if (!decompress_contents (compressed_buffer, compressed_size,
 225                                 uncompressed_buffer, uncompressed_size))
 226         {
 227           bfd_set_error (bfd_error_bad_value);
 228           free (uncompressed_buffer);
 229         fail_compressed:
 230           free (compressed_buffer);
 231           return FALSE;
 232         }
 233
 234       free (compressed_buffer);
 235       sec->contents = uncompressed_buffer;
 236       sec->compress_status = COMPRESS_SECTION_DONE;
 237       /* Fall thru */
 238 #endif
 239
 240     case COMPRESS_SECTION_DONE:
 241       if (p == NULL)
 242         {
 243           p = (bfd_byte *) bfd_malloc (sz);
 244           if (p == NULL)
 245             return FALSE;
 246           *ptr = p;
 247         }
 248       memcpy (p, sec->contents, sz);
 249       return TRUE;
 250
 251     default:
 252       abort ();
 253     }
 254 }
 255
 256 /*
 257 FUNCTION
 258         bfd_is_section_compressed
 259
 260 SYNOPSIS
 261         bfd_boolean bfd_is_section_compressed
 262           (bfd *abfd, asection *section);
 263
 264 DESCRIPTION
 265         Return @code{TRUE} if @var{section} is compressed.
 266 */
 267
 268 bfd_boolean
 269 bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
 270 {
 271   bfd_byte compressed_buffer [12];
 272
 273   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 274      by the uncompressed section size, 8 bytes in big-endian order.  */
 275   return (bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12)
 276           && CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"));
 277 }
 278
 279 /*
 280 FUNCTION
 281         bfd_init_section_decompress_status
 282
 283 SYNOPSIS
 284         bfd_boolean bfd_init_section_decompress_status
 285           (bfd *abfd, asection *section);
 286
 287 DESCRIPTION
 288         Record compressed section size, update section size with
 289         decompressed size and set compress_status to
 290         DECOMPRESS_SECTION_SIZED.
 291
 292         Return @code{FALSE} if the section is not a valid compressed
 293         section or zlib is not installed on this machine.  Otherwise,
 294         return @code{TRUE}.
 295 */
 296
 297 bfd_boolean
 298 bfd_init_section_decompress_status (bfd *abfd ATTRIBUTE_UNUSED,
 299                                     sec_ptr sec ATTRIBUTE_UNUSED)
 300 {
 301 #ifndef HAVE_ZLIB_H
 302   bfd_set_error (bfd_error_invalid_operation);
 303   return FALSE;
 304 #else
 305   bfd_byte compressed_buffer [12];
 306   bfd_size_type uncompressed_size;
 307
 308   if (sec->rawsize != 0
 309       || sec->contents != NULL
 310       || sec->compress_status != COMPRESS_SECTION_NONE
 311       || !bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12))
 312     {
 313       bfd_set_error (bfd_error_invalid_operation);
 314       return FALSE;
 315     }
 316
 317   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 318      by the uncompressed section size, 8 bytes in big-endian order.  */
 319   if (! CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"))
 320     {
 321       bfd_set_error (bfd_error_wrong_format);
 322       return FALSE;
 323     }
 324
 325   uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
 326   uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
 327   uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
 328   uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
 329   uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
 330   uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
 331   uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
 332   uncompressed_size += compressed_buffer[11];
 333
 334   sec->compressed_size = sec->size;
 335   sec->size = uncompressed_size;
 336   sec->compress_status = DECOMPRESS_SECTION_SIZED;
 337
 338   return TRUE;
 339 #endif
 340 }
 341
 342 /*
 343 FUNCTION
 344         bfd_init_section_compress_status
 345
 346 SYNOPSIS
 347         bfd_boolean bfd_init_section_compress_status
 348           (bfd *abfd, asection *section);
 349
 350 DESCRIPTION
 351         If open for read, compress section, update section size with
 352         compressed size and set compress_status to COMPRESS_SECTION_DONE.
 353
 354         Return @code{FALSE} if the section is not a valid compressed
 355         section or zlib is not installed on this machine.  Otherwise,
 356         return @code{TRUE}.
 357 */
 358
 359 bfd_boolean
 360 bfd_init_section_compress_status (bfd *abfd ATTRIBUTE_UNUSED,
 361                                   sec_ptr sec ATTRIBUTE_UNUSED)
 362 {
 363 #ifndef HAVE_ZLIB_H
 364   bfd_set_error (bfd_error_invalid_operation);
 365   return FALSE;
 366 #else
 367   bfd_size_type uncompressed_size;
 368   bfd_byte *uncompressed_buffer;
 369   bfd_boolean ret;
 370
 371   /* Error if not opened for read.  */
 372   if (abfd->direction != read_direction
 373       || sec->size == 0
 374       || sec->rawsize != 0
 375       || sec->contents != NULL
 376       || sec->compress_status != COMPRESS_SECTION_NONE)
 377     {
 378       bfd_set_error (bfd_error_invalid_operation);
 379       return FALSE;
 380     }
 381
 382   /* Read in the full section contents and compress it.  */
 383   uncompressed_size = sec->size;
 384   uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 385   if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer,
 386                                  0, uncompressed_size))
 387     ret = FALSE;
 388   else
 389     ret = bfd_compress_section_contents (abfd, sec,
 390                                          uncompressed_buffer,
 391                                          uncompressed_size);
 392
 393   free (uncompressed_buffer);
 394   return ret;
 395 #endif
 396 }