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