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 ? FALSE: TRUE;
  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 (compress ((Bytef*) compressed_buffer + 12,
 104                 &compressed_size,
 105                 (const Bytef*) uncompressed_buffer,
 106                 uncompressed_size) != Z_OK)
 107     {
 108       free (compressed_buffer);
 109       bfd_set_error (bfd_error_bad_value);
 110       return FALSE;
 111     }
 112
 113   /* Write the zlib header.  In this case, it should be "ZLIB" followed
 114      by the uncompressed section size, 8 bytes in big-endian order.  */
 115   memcpy (compressed_buffer, "ZLIB", 4);
 116   compressed_buffer[11] = uncompressed_size; uncompressed_size >>= 8;
 117   compressed_buffer[10] = uncompressed_size; uncompressed_size >>= 8;
 118   compressed_buffer[9] = uncompressed_size; uncompressed_size >>= 8;
 119   compressed_buffer[8] = uncompressed_size; uncompressed_size >>= 8;
 120   compressed_buffer[7] = uncompressed_size; uncompressed_size >>= 8;
 121   compressed_buffer[6] = uncompressed_size; uncompressed_size >>= 8;
 122   compressed_buffer[5] = uncompressed_size; uncompressed_size >>= 8;
 123   compressed_buffer[4] = uncompressed_size;
 124   compressed_size += 12;
 125
 126   /* Free the uncompressed contents if we compress in place.  */
 127   if (uncompressed_buffer == sec->contents)
 128     free (uncompressed_buffer);
 129
 130   sec->contents = compressed_buffer;
 131   sec->size = compressed_size;
 132   sec->compress_status = COMPRESS_SECTION_DONE;
 133
 134   return TRUE;
 135 #endif  /* HAVE_ZLIB_H */
 136 }
 137
 138 /*
 139 FUNCTION
 140         bfd_get_full_section_contents
 141
 142 SYNOPSIS
 143         bfd_boolean bfd_get_full_section_contents
 144           (bfd *abfd, asection *section, bfd_byte **ptr);
 145
 146 DESCRIPTION
 147         Read all data from @var{section} in BFD @var{abfd}, decompress
 148         if needed, and store in @var{*ptr}.  If @var{*ptr} is NULL,
 149         return @var{*ptr} with memory malloc'd by this function.
 150
 151         Return @code{TRUE} if the full section contents is retrieved
 152         successfully.
 153 */
 154
 155 bfd_boolean
 156 bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr)
 157 {
 158   bfd_size_type sz = sec->rawsize ? sec->rawsize : sec->size;
 159   bfd_byte *p = *ptr;
 160   bfd_boolean need_free, ret;
 161 #ifdef HAVE_ZLIB_H
 162   bfd_size_type compressed_size;
 163   bfd_size_type uncompressed_size;
 164   bfd_size_type rawsize;
 165   bfd_byte *compressed_buffer;
 166   bfd_byte *uncompressed_buffer;
 167 #endif
 168
 169   if (sz == 0)
 170     return TRUE;
 171
 172   switch (sec->compress_status)
 173     {
 174     case COMPRESS_SECTION_NONE:
 175       if (p == NULL)
 176         {
 177           p = (bfd_byte *) bfd_malloc (sz);
 178           if (p == NULL)
 179             return FALSE;
 180           need_free = TRUE;
 181           *ptr = p;
 182         }
 183       else
 184         need_free = FALSE;
 185       ret = bfd_get_section_contents (abfd, sec, p, 0, sz);
 186       if (!ret && need_free)
 187         free (p);
 188       return ret;
 189
 190     case COMPRESS_SECTION_DONE:
 191       if (p)
 192         memcpy (p, sec->contents, sz);
 193       else
 194         *ptr = sec->contents;
 195       return TRUE;
 196
 197     case DECOMPRESS_SECTION_SIZED:
 198       break;
 199
 200     default:
 201       abort ();
 202     }
 203
 204 #ifndef HAVE_ZLIB_H
 205   bfd_set_error (bfd_error_invalid_operation);
 206   return FALSE;
 207 #else
 208   /* Read in the full compressed section contents.  */
 209   uncompressed_size = sec->size;
 210   compressed_size = sec->compressed_size;
 211   compressed_buffer = (bfd_byte *) bfd_malloc (compressed_size);
 212   rawsize = sec->rawsize;
 213   /* Clear rawsize, set size to compressed size and set compress_status
 214      to COMPRESS_SECTION_NONE.  If the compressed size is bigger than
 215      the uncompressed size, bfd_get_section_contents will fail.  */
 216   sec->rawsize = 0;
 217   sec->size = compressed_size;
 218   sec->compress_status = COMPRESS_SECTION_NONE;
 219   ret = bfd_get_section_contents (abfd, sec, compressed_buffer,
 220                                   0, compressed_size);
 221   /* Restore rawsize and size.  */
 222   sec->rawsize = rawsize;
 223   sec->size = uncompressed_size;
 224   if (!ret)
 225     {
 226 fail_compressed:
 227       sec->compress_status = DECOMPRESS_SECTION_SIZED;
 228       free (compressed_buffer);
 229       return ret;
 230     }
 231
 232   /* Decompress to caller buffer directly if it is provided. */
 233   if (p)
 234     uncompressed_buffer = p;
 235   else
 236     {
 237       uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 238       if (uncompressed_buffer == NULL)
 239         goto fail_compressed;
 240     }
 241
 242   if (!decompress_contents (compressed_buffer, compressed_size,
 243                             uncompressed_buffer, uncompressed_size))
 244     {
 245       sec->compress_status = DECOMPRESS_SECTION_SIZED;
 246       free (compressed_buffer);
 247       if (p == NULL)
 248         free (uncompressed_buffer);
 249       bfd_set_error (bfd_error_bad_value);
 250       return FALSE;
 251     }
 252
 253   free (compressed_buffer);
 254   if (p == NULL)
 255     *ptr = uncompressed_buffer;
 256
 257   sec->contents = uncompressed_buffer;
 258   sec->compress_status = COMPRESS_SECTION_DONE;
 259
 260   return TRUE;
 261 #endif
 262 }
 263
 264 /*
 265 FUNCTION
 266         bfd_is_section_compressed
 267
 268 SYNOPSIS
 269         bfd_boolean bfd_is_section_compressed
 270           (bfd *abfd, asection *section);
 271
 272 DESCRIPTION
 273         Return @code{TRUE} if @var{section} is compressed.
 274 */
 275
 276 bfd_boolean
 277 bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
 278 {
 279   bfd_byte compressed_buffer [12];
 280
 281   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 282      by the uncompressed section size, 8 bytes in big-endian order.  */
 283   return (bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12)
 284           && CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"));
 285 }
 286
 287 /*
 288 FUNCTION
 289         bfd_init_section_decompress_status
 290
 291 SYNOPSIS
 292         bfd_boolean bfd_init_section_decompress_status
 293           (bfd *abfd, asection *section);
 294
 295 DESCRIPTION
 296         Record compressed section size, update section size with
 297         decompressed size and set compress_status to
 298         DECOMPRESS_SECTION_SIZED.
 299
 300         Return @code{FALSE} if the section is not a valid compressed
 301         section or zlib is not installed on this machine.  Otherwise,
 302         return @code{TRUE}.
 303 */
 304
 305 bfd_boolean
 306 bfd_init_section_decompress_status (bfd *abfd ATTRIBUTE_UNUSED,
 307                                     sec_ptr sec ATTRIBUTE_UNUSED)
 308 {
 309 #ifndef HAVE_ZLIB_H
 310   bfd_set_error (bfd_error_invalid_operation);
 311   return FALSE;
 312 #else
 313   bfd_byte compressed_buffer [12];
 314   bfd_size_type uncompressed_size;
 315
 316   if (sec->rawsize != 0
 317       || sec->contents != NULL
 318       || sec->compress_status != COMPRESS_SECTION_NONE
 319       || !bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12))
 320     {
 321       bfd_set_error (bfd_error_invalid_operation);
 322       return FALSE;
 323     }
 324
 325   /* Read the zlib header.  In this case, it should be "ZLIB" followed
 326      by the uncompressed section size, 8 bytes in big-endian order.  */
 327   if (! CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"))
 328     {
 329       bfd_set_error (bfd_error_wrong_format);
 330       return FALSE;
 331     }
 332
 333   uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
 334   uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
 335   uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
 336   uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
 337   uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
 338   uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
 339   uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
 340   uncompressed_size += compressed_buffer[11];
 341
 342   sec->compressed_size = sec->size;
 343   sec->size = uncompressed_size;
 344   sec->compress_status = DECOMPRESS_SECTION_SIZED;
 345
 346   return TRUE;
 347 #endif
 348 }
 349
 350 /*
 351 FUNCTION
 352         bfd_init_section_compress_status
 353
 354 SYNOPSIS
 355         bfd_boolean bfd_init_section_compress_status
 356           (bfd *abfd, asection *section);
 357
 358 DESCRIPTION
 359         If open for read, compress section, update section size with
 360         compressed size and set compress_status to COMPRESS_SECTION_DONE.
 361
 362         Return @code{FALSE} if the section is not a valid compressed
 363         section or zlib is not installed on this machine.  Otherwise,
 364         return @code{TRUE}.
 365 */
 366
 367 bfd_boolean
 368 bfd_init_section_compress_status (bfd *abfd ATTRIBUTE_UNUSED,
 369                                   sec_ptr sec ATTRIBUTE_UNUSED)
 370 {
 371 #ifndef HAVE_ZLIB_H
 372   bfd_set_error (bfd_error_invalid_operation);
 373   return FALSE;
 374 #else
 375   bfd_size_type uncompressed_size;
 376   bfd_byte *uncompressed_buffer;
 377   bfd_boolean ret;
 378
 379   /* Error if not opened for read.  */
 380   if (abfd->direction != read_direction
 381       || sec->size == 0
 382       || sec->rawsize != 0
 383       || sec->contents != NULL
 384       || sec->compress_status != COMPRESS_SECTION_NONE)
 385     {
 386       bfd_set_error (bfd_error_invalid_operation);
 387       return FALSE;
 388     }
 389
 390   /* Read in the full section contents and compress it.  */
 391   uncompressed_size = sec->size;
 392   uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
 393   if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer,
 394                                  0, uncompressed_size))
 395     ret = FALSE;
 396   else
 397     ret = bfd_compress_section_contents (abfd, sec,
 398                                          uncompressed_buffer,
 399                                          uncompressed_size);
 400
 401   free (uncompressed_buffer);
 402   return ret;
 403 #endif
 404 }