bfd/compress.c

   1 /* Compressed section support (intended for debug sections).
   2    Copyright 2008, 2010, 2011
   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;
 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 (abfd->direction != write_direction && sec->rawsize != 0)
 173     sz = sec->rawsize;
 174   else
 175     sz = sec->size;
 176   if (sz == 0)
 177     return TRUE;
 178
 179   switch (sec->compress_status)
 180     {
 181     case COMPRESS_SECTION_NONE:
 182       if (p == NULL)
 183         {
 184           p = (bfd_byte *) bfd_malloc (sz);
 185           if (p == NULL)
 186             return FALSE;
 187         }
 188       if (!bfd_get_section_contents (abfd, sec, p, 0, sz))
 189         {
 190           if (*ptr != p)
 191             free (p);
 192           return FALSE;
 193         }
 194       *ptr = p;
 195       return TRUE;
 196
 197     case DECOMPRESS_SECTION_SIZED:
 198 #ifndef HAVE_ZLIB_H
 199       bfd_set_error (bfd_error_invalid_operation);
 200       return FALSE;
 201 #else
 202       /* Read in the full compressed section contents.  */
 203       uncompressed_size = sec->size;
 204       compressed_size = sec->compressed_size;
 205       compressed_buffer = (bfd_byte *) bfd_malloc (compressed_size);
 206       if (compressed_buffer == NULL)
 207         return FALSE;
 208       rawsize = sec->rawsize;
 209       /* Clear rawsize, set size to compressed size and set compress_status
 210          to COMPRESS_SECTION_NONE.  If the compressed size is bigger than
 211          the uncompressed size, bfd_get_section_contents will fail.  */
 212       sec->rawsize = 0;
 213       sec->size = compressed_size;
 214       sec->compress_status = COMPRESS_SECTION_NONE;
 215       ret = bfd_get_section_contents (abfd, sec, compressed_buffer,
 216                                       0, compressed_size);
 217       /* Restore rawsize and size.  */
 218       sec->rawsize = rawsize;
 219       sec->size = uncompressed_size;
 220       sec->compress_status = DECOMPRESS_SECTION_SIZED;
 221       if (!ret)
 222         goto fail_compressed;
 223
 224       uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 225       if (uncompressed_buffer == NULL)
 226         goto fail_compressed;
 227
 228       if (!decompress_contents (compressed_buffer, compressed_size,
 229                                 uncompressed_buffer, uncompressed_size))
 230         {
 231           bfd_set_error (bfd_error_bad_value);
 232           free (uncompressed_buffer);
 233         fail_compressed:
 234           free (compressed_buffer);
 235           return FALSE;
 236         }
 237
 238       free (compressed_buffer);
 239       sec->contents = uncompressed_buffer;
 240       sec->compress_status = COMPRESS_SECTION_DONE;
 241       /* Fall thru */
 242 #endif
 243
 244     case COMPRESS_SECTION_DONE:
 245       if (p == NULL)
 246         {
 247           p = (bfd_byte *) bfd_malloc (sz);
 248           if (p == NULL)
 249             return FALSE;
 250           *ptr = p;
 251         }
 252       memcpy (p, sec->contents, sz);
 253       return TRUE;
 254
 255     default:
 256       abort ();
 257     }
 258 }
 259
 260 /*
 261 FUNCTION
 262         bfd_is_section_compressed
 263
 264 SYNOPSIS
 265         bfd_boolean bfd_is_section_compressed
 266           (bfd *abfd, asection *section);
 267
 268 DESCRIPTION
 269         Return @code{TRUE} if @var{section} is compressed.
 270 */
 271
 272 bfd_boolean
 273 bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
 274 {
 275   bfd_byte compressed_buffer [12];
 276
 277   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 278      by the uncompressed section size, 8 bytes in big-endian order.  */
 279   return (bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12)
 280           && CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"));
 281 }
 282
 283 /*
 284 FUNCTION
 285         bfd_init_section_decompress_status
 286
 287 SYNOPSIS
 288         bfd_boolean bfd_init_section_decompress_status
 289           (bfd *abfd, asection *section);
 290
 291 DESCRIPTION
 292         Record compressed section size, update section size with
 293         decompressed size and set compress_status to
 294         DECOMPRESS_SECTION_SIZED.
 295
 296         Return @code{FALSE} if the section is not a valid compressed
 297         section or zlib is not installed on this machine.  Otherwise,
 298         return @code{TRUE}.
 299 */
 300
 301 bfd_boolean
 302 bfd_init_section_decompress_status (bfd *abfd ATTRIBUTE_UNUSED,
 303                                     sec_ptr sec ATTRIBUTE_UNUSED)
 304 {
 305 #ifndef HAVE_ZLIB_H
 306   bfd_set_error (bfd_error_invalid_operation);
 307   return FALSE;
 308 #else
 309   bfd_byte compressed_buffer [12];
 310   bfd_size_type uncompressed_size;
 311
 312   if (sec->rawsize != 0
 313       || sec->contents != NULL
 314       || sec->compress_status != COMPRESS_SECTION_NONE
 315       || !bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12))
 316     {
 317       bfd_set_error (bfd_error_invalid_operation);
 318       return FALSE;
 319     }
 320
 321   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 322      by the uncompressed section size, 8 bytes in big-endian order.  */
 323   if (! CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"))
 324     {
 325       bfd_set_error (bfd_error_wrong_format);
 326       return FALSE;
 327     }
 328
 329   uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
 330   uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
 331   uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
 332   uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
 333   uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
 334   uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
 335   uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
 336   uncompressed_size += compressed_buffer[11];
 337
 338   sec->compressed_size = sec->size;
 339   sec->size = uncompressed_size;
 340   sec->compress_status = DECOMPRESS_SECTION_SIZED;
 341
 342   return TRUE;
 343 #endif
 344 }
 345
 346 /*
 347 FUNCTION
 348         bfd_init_section_compress_status
 349
 350 SYNOPSIS
 351         bfd_boolean bfd_init_section_compress_status
 352           (bfd *abfd, asection *section);
 353
 354 DESCRIPTION
 355         If open for read, compress section, update section size with
 356         compressed size and set compress_status to COMPRESS_SECTION_DONE.
 357
 358         Return @code{FALSE} if the section is not a valid compressed
 359         section or zlib is not installed on this machine.  Otherwise,
 360         return @code{TRUE}.
 361 */
 362
 363 bfd_boolean
 364 bfd_init_section_compress_status (bfd *abfd ATTRIBUTE_UNUSED,
 365                                   sec_ptr sec ATTRIBUTE_UNUSED)
 366 {
 367 #ifndef HAVE_ZLIB_H
 368   bfd_set_error (bfd_error_invalid_operation);
 369   return FALSE;
 370 #else
 371   bfd_size_type uncompressed_size;
 372   bfd_byte *uncompressed_buffer;
 373   bfd_boolean ret;
 374
 375   /* Error if not opened for read.  */
 376   if (abfd->direction != read_direction
 377       || sec->size == 0
 378       || sec->rawsize != 0
 379       || sec->contents != NULL
 380       || sec->compress_status != COMPRESS_SECTION_NONE)
 381     {
 382       bfd_set_error (bfd_error_invalid_operation);
 383       return FALSE;
 384     }
 385
 386   /* Read in the full section contents and compress it.  */
 387   uncompressed_size = sec->size;
 388   uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 389   if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer,
 390                                  0, uncompressed_size))
 391     ret = FALSE;
 392   else
 393     ret = bfd_compress_section_contents (abfd, sec,
 394                                          uncompressed_buffer,
 395                                          uncompressed_size);
 396
 397   free (uncompressed_buffer);
 398   return ret;
 399 #endif
 400 }