bfd/compress.c

   1 /* Compressed section support (intended for debug sections).
   2    Copyright 2008, 2010, 2011, 2012
   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 "sysdep.h"
  23 #include "bfd.h"
  24 #include "libbfd.h"
  25 #ifdef HAVE_ZLIB_H
  26 #include <zlib.h>
  27 #endif
  28
  29 #ifdef HAVE_ZLIB_H
  30 static bfd_boolean
  31 decompress_contents (bfd_byte *compressed_buffer,
  32                      bfd_size_type compressed_size,
  33                      bfd_byte *uncompressed_buffer,
  34                      bfd_size_type uncompressed_size)
  35 {
  36   z_stream strm;
  37   int rc;
  38
  39   /* It is possible the section consists of several compressed
  40      buffers concatenated together, so we uncompress in a loop.  */
  41   strm.zalloc = NULL;
  42   strm.zfree = NULL;
  43   strm.opaque = NULL;
  44   strm.avail_in = compressed_size - 12;
  45   strm.next_in = (Bytef*) compressed_buffer + 12;
  46   strm.avail_out = uncompressed_size;
  47
  48   rc = inflateInit (&strm);
  49   while (strm.avail_in > 0)
  50     {
  51       if (rc != Z_OK)
  52         return FALSE;
  53       strm.next_out = ((Bytef*) uncompressed_buffer
  54                        + (uncompressed_size - strm.avail_out));
  55       rc = inflate (&strm, Z_FINISH);
  56       if (rc != Z_STREAM_END)
  57         return FALSE;
  58       rc = inflateReset (&strm);
  59     }
  60   rc = inflateEnd (&strm);
  61   return rc == Z_OK && strm.avail_out == 0;
  62 }
  63 #endif
  64
  65 /*
  66 FUNCTION
  67         bfd_compress_section_contents
  68
  69 SYNOPSIS
  70         bfd_boolean bfd_compress_section_contents
  71           (bfd *abfd, asection *section, bfd_byte *uncompressed_buffer,
  72            bfd_size_type uncompressed_size);
  73
  74 DESCRIPTION
  75
  76         Compress data of the size specified in @var{uncompressed_size}
  77         and pointed to by @var{uncompressed_buffer} using zlib and store
  78         as the contents field.  This function assumes the contents
  79         field was allocated using bfd_malloc() or equivalent.  If zlib
  80         is not installed on this machine, the input is unmodified.
  81
  82         Return @code{TRUE} if the full section contents is compressed
  83         successfully.
  84 */
  85
  86 bfd_boolean
  87 bfd_compress_section_contents (bfd *abfd ATTRIBUTE_UNUSED,
  88                                sec_ptr sec ATTRIBUTE_UNUSED,
  89                                bfd_byte *uncompressed_buffer ATTRIBUTE_UNUSED,
  90                                bfd_size_type uncompressed_size ATTRIBUTE_UNUSED)
  91 {
  92 #ifndef HAVE_ZLIB_H
  93   bfd_set_error (bfd_error_invalid_operation);
  94   return FALSE;
  95 #else
  96   uLong compressed_size;
  97   bfd_byte *compressed_buffer;
  98
  99   compressed_size = compressBound (uncompressed_size) + 12;
 100   compressed_buffer = (bfd_byte *) bfd_malloc (compressed_size);
 101
 102   if (compressed_buffer == NULL)
 103     return FALSE;
 104
 105   if (compress ((Bytef*) compressed_buffer + 12,
 106                 &compressed_size,
 107                 (const Bytef*) uncompressed_buffer,
 108                 uncompressed_size) != Z_OK)
 109     {
 110       free (compressed_buffer);
 111       bfd_set_error (bfd_error_bad_value);
 112       return FALSE;
 113     }
 114
 115   /* Write the zlib header.  In this case, it should be "ZLIB" followed
 116      by the uncompressed section size, 8 bytes in big-endian order.  */
 117   memcpy (compressed_buffer, "ZLIB", 4);
 118   compressed_buffer[11] = uncompressed_size; uncompressed_size >>= 8;
 119   compressed_buffer[10] = uncompressed_size; uncompressed_size >>= 8;
 120   compressed_buffer[9] = uncompressed_size; uncompressed_size >>= 8;
 121   compressed_buffer[8] = uncompressed_size; uncompressed_size >>= 8;
 122   compressed_buffer[7] = uncompressed_size; uncompressed_size >>= 8;
 123   compressed_buffer[6] = uncompressed_size; uncompressed_size >>= 8;
 124   compressed_buffer[5] = uncompressed_size; uncompressed_size >>= 8;
 125   compressed_buffer[4] = uncompressed_size;
 126   compressed_size += 12;
 127
 128   /* Free the uncompressed contents if we compress in place.  */
 129   if (uncompressed_buffer == sec->contents)
 130     free (uncompressed_buffer);
 131
 132   sec->contents = compressed_buffer;
 133   sec->size = compressed_size;
 134   sec->compress_status = COMPRESS_SECTION_DONE;
 135
 136   return TRUE;
 137 #endif  /* HAVE_ZLIB_H */
 138 }
 139
 140 /*
 141 FUNCTION
 142         bfd_get_full_section_contents
 143
 144 SYNOPSIS
 145         bfd_boolean bfd_get_full_section_contents
 146           (bfd *abfd, asection *section, bfd_byte **ptr);
 147
 148 DESCRIPTION
 149         Read all data from @var{section} in BFD @var{abfd}, decompress
 150         if needed, and store in @var{*ptr}.  If @var{*ptr} is NULL,
 151         return @var{*ptr} with memory malloc'd by this function.
 152
 153         Return @code{TRUE} if the full section contents is retrieved
 154         successfully.
 155 */
 156
 157 bfd_boolean
 158 bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr)
 159 {
 160   bfd_size_type sz;
 161   bfd_byte *p = *ptr;
 162 #ifdef HAVE_ZLIB_H
 163   bfd_boolean ret;
 164   bfd_size_type compressed_size;
 165   bfd_size_type uncompressed_size;
 166   bfd_size_type rawsize;
 167   bfd_byte *compressed_buffer;
 168   bfd_byte *uncompressed_buffer;
 169 #endif
 170
 171   if (abfd->direction != write_direction && sec->rawsize != 0)
 172     sz = sec->rawsize;
 173   else
 174     sz = sec->size;
 175   if (sz == 0)
 176     return TRUE;
 177
 178   switch (sec->compress_status)
 179     {
 180     case COMPRESS_SECTION_NONE:
 181       if (p == NULL)
 182         {
 183           p = (bfd_byte *) bfd_malloc (sz);
 184           if (p == NULL)
 185             return FALSE;
 186         }
 187       if (!bfd_get_section_contents (abfd, sec, p, 0, sz))
 188         {
 189           if (*ptr != p)
 190             free (p);
 191           return FALSE;
 192         }
 193       *ptr = p;
 194       return TRUE;
 195
 196     case DECOMPRESS_SECTION_SIZED:
 197 #ifndef HAVE_ZLIB_H
 198       bfd_set_error (bfd_error_invalid_operation);
 199       return FALSE;
 200 #else
 201       /* Read in the full compressed section contents.  */
 202       uncompressed_size = sec->size;
 203       compressed_size = sec->compressed_size;
 204       compressed_buffer = (bfd_byte *) bfd_malloc (compressed_size);
 205       if (compressed_buffer == NULL)
 206         return FALSE;
 207       rawsize = sec->rawsize;
 208       /* Clear rawsize, set size to compressed size and set compress_status
 209          to COMPRESS_SECTION_NONE.  If the compressed size is bigger than
 210          the uncompressed size, bfd_get_section_contents will fail.  */
 211       sec->rawsize = 0;
 212       sec->size = compressed_size;
 213       sec->compress_status = COMPRESS_SECTION_NONE;
 214       ret = bfd_get_section_contents (abfd, sec, compressed_buffer,
 215                                       0, compressed_size);
 216       /* Restore rawsize and size.  */
 217       sec->rawsize = rawsize;
 218       sec->size = uncompressed_size;
 219       sec->compress_status = DECOMPRESS_SECTION_SIZED;
 220       if (!ret)
 221         goto fail_compressed;
 222
 223       uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 224       if (uncompressed_buffer == NULL)
 225         goto fail_compressed;
 226
 227       if (!decompress_contents (compressed_buffer, compressed_size,
 228                                 uncompressed_buffer, uncompressed_size))
 229         {
 230           bfd_set_error (bfd_error_bad_value);
 231           free (uncompressed_buffer);
 232         fail_compressed:
 233           free (compressed_buffer);
 234           return FALSE;
 235         }
 236
 237       free (compressed_buffer);
 238       sec->contents = uncompressed_buffer;
 239       sec->compress_status = COMPRESS_SECTION_DONE;
 240       /* Fall thru */
 241 #endif
 242
 243     case COMPRESS_SECTION_DONE:
 244       if (p == NULL)
 245         {
 246           p = (bfd_byte *) bfd_malloc (sz);
 247           if (p == NULL)
 248             return FALSE;
 249           *ptr = p;
 250         }
 251       memcpy (p, sec->contents, sz);
 252       return TRUE;
 253
 254     default:
 255       abort ();
 256     }
 257 }
 258
 259 /*
 260 FUNCTION
 261         bfd_is_section_compressed
 262
 263 SYNOPSIS
 264         bfd_boolean bfd_is_section_compressed
 265           (bfd *abfd, asection *section);
 266
 267 DESCRIPTION
 268         Return @code{TRUE} if @var{section} is compressed.
 269 */
 270
 271 bfd_boolean
 272 bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
 273 {
 274   bfd_byte compressed_buffer [12];
 275
 276   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 277      by the uncompressed section size, 8 bytes in big-endian order.  */
 278   return (bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12)
 279           && CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"));
 280 }
 281
 282 /*
 283 FUNCTION
 284         bfd_init_section_decompress_status
 285
 286 SYNOPSIS
 287         bfd_boolean bfd_init_section_decompress_status
 288           (bfd *abfd, asection *section);
 289
 290 DESCRIPTION
 291         Record compressed section size, update section size with
 292         decompressed size and set compress_status to
 293         DECOMPRESS_SECTION_SIZED.
 294
 295         Return @code{FALSE} if the section is not a valid compressed
 296         section or zlib is not installed on this machine.  Otherwise,
 297         return @code{TRUE}.
 298 */
 299
 300 bfd_boolean
 301 bfd_init_section_decompress_status (bfd *abfd ATTRIBUTE_UNUSED,
 302                                     sec_ptr sec ATTRIBUTE_UNUSED)
 303 {
 304 #ifndef HAVE_ZLIB_H
 305   bfd_set_error (bfd_error_invalid_operation);
 306   return FALSE;
 307 #else
 308   bfd_byte compressed_buffer [12];
 309   bfd_size_type uncompressed_size;
 310
 311   if (sec->rawsize != 0
 312       || sec->contents != NULL
 313       || sec->compress_status != COMPRESS_SECTION_NONE
 314       || !bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12))
 315     {
 316       bfd_set_error (bfd_error_invalid_operation);
 317       return FALSE;
 318     }
 319
 320   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 321      by the uncompressed section size, 8 bytes in big-endian order.  */
 322   if (! CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"))
 323     {
 324       bfd_set_error (bfd_error_wrong_format);
 325       return FALSE;
 326     }
 327
 328   uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
 329   uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
 330   uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
 331   uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
 332   uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
 333   uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
 334   uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
 335   uncompressed_size += compressed_buffer[11];
 336
 337   sec->compressed_size = sec->size;
 338   sec->size = uncompressed_size;
 339   sec->compress_status = DECOMPRESS_SECTION_SIZED;
 340
 341   return TRUE;
 342 #endif
 343 }
 344
 345 /*
 346 FUNCTION
 347         bfd_init_section_compress_status
 348
 349 SYNOPSIS
 350         bfd_boolean bfd_init_section_compress_status
 351           (bfd *abfd, asection *section);
 352
 353 DESCRIPTION
 354         If open for read, compress section, update section size with
 355         compressed size and set compress_status to COMPRESS_SECTION_DONE.
 356
 357         Return @code{FALSE} if the section is not a valid compressed
 358         section or zlib is not installed on this machine.  Otherwise,
 359         return @code{TRUE}.
 360 */
 361
 362 bfd_boolean
 363 bfd_init_section_compress_status (bfd *abfd ATTRIBUTE_UNUSED,
 364                                   sec_ptr sec ATTRIBUTE_UNUSED)
 365 {
 366 #ifndef HAVE_ZLIB_H
 367   bfd_set_error (bfd_error_invalid_operation);
 368   return FALSE;
 369 #else
 370   bfd_size_type uncompressed_size;
 371   bfd_byte *uncompressed_buffer;
 372   bfd_boolean ret;
 373
 374   /* Error if not opened for read.  */
 375   if (abfd->direction != read_direction
 376       || sec->size == 0
 377       || sec->rawsize != 0
 378       || sec->contents != NULL
 379       || sec->compress_status != COMPRESS_SECTION_NONE)
 380     {
 381       bfd_set_error (bfd_error_invalid_operation);
 382       return FALSE;
 383     }
 384
 385   /* Read in the full section contents and compress it.  */
 386   uncompressed_size = sec->size;
 387   uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 388   if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer,
 389                                  0, uncompressed_size))
 390     ret = FALSE;
 391   else
 392     ret = bfd_compress_section_contents (abfd, sec,
 393                                          uncompressed_buffer,
 394                                          uncompressed_size);
 395
 396   free (uncompressed_buffer);
 397   return ret;
 398 #endif
 399 }