1 /* Compressed section support (intended for debug sections). 2 Copyright (C) 2008-2014 Free Software Foundation, Inc. 3 4 This file is part of BFD, the Binary File Descriptor library. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 19 MA 02110-1301, USA. */ 20 21 #include "sysdep.h" 22 #include "bfd.h" 23 #include "libbfd.h" 24 #ifdef HAVE_ZLIB_H 25 #include <zlib.h> 26 #endif 27 #include "safe-ctype.h" 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 BFD_ASSERT (Z_OK == 0); 49 rc = inflateInit (&strm); 50 while (strm.avail_in > 0 && strm.avail_out > 0) 51 { 52 if (rc != Z_OK) 53 break; 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 break; 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 save_size; 166 bfd_size_type save_rawsize; 167 bfd_byte *compressed_buffer; 168 #endif 169 170 if (abfd->direction != write_direction && sec->rawsize != 0) 171 sz = sec->rawsize; 172 else 173 sz = sec->size; 174 if (sz == 0) 175 return TRUE; 176 177 switch (sec->compress_status) 178 { 179 case COMPRESS_SECTION_NONE: 180 if (p == NULL) 181 { 182 p = (bfd_byte *) bfd_malloc (sz); 183 if (p == NULL) 184 return FALSE; 185 } 186 if (!bfd_get_section_contents (abfd, sec, p, 0, sz)) 187 { 188 if (*ptr != p) 189 free (p); 190 return FALSE; 191 } 192 *ptr = p; 193 return TRUE; 194 195 case DECOMPRESS_SECTION_SIZED: 196 #ifndef HAVE_ZLIB_H 197 bfd_set_error (bfd_error_invalid_operation); 198 return FALSE; 199 #else 200 /* Read in the full compressed section contents. */ 201 compressed_buffer = (bfd_byte *) bfd_malloc (sec->compressed_size); 202 if (compressed_buffer == NULL) 203 return FALSE; 204 save_rawsize = sec->rawsize; 205 save_size = sec->size; 206 /* Clear rawsize, set size to compressed size and set compress_status 207 to COMPRESS_SECTION_NONE. If the compressed size is bigger than 208 the uncompressed size, bfd_get_section_contents will fail. */ 209 sec->rawsize = 0; 210 sec->size = sec->compressed_size; 211 sec->compress_status = COMPRESS_SECTION_NONE; 212 ret = bfd_get_section_contents (abfd, sec, compressed_buffer, 213 0, sec->compressed_size); 214 /* Restore rawsize and size. */ 215 sec->rawsize = save_rawsize; 216 sec->size = save_size; 217 sec->compress_status = DECOMPRESS_SECTION_SIZED; 218 if (!ret) 219 goto fail_compressed; 220 221 if (p == NULL) 222 p = (bfd_byte *) bfd_malloc (sz); 223 if (p == NULL) 224 goto fail_compressed; 225 226 if (!decompress_contents (compressed_buffer, sec->compressed_size, p, sz)) 227 { 228 bfd_set_error (bfd_error_bad_value); 229 if (p != *ptr) 230 free (p); 231 fail_compressed: 232 free (compressed_buffer); 233 return FALSE; 234 } 235 236 free (compressed_buffer); 237 *ptr = p; 238 return TRUE; 239 #endif 240 241 case COMPRESS_SECTION_DONE: 242 if (p == NULL) 243 { 244 p = (bfd_byte *) bfd_malloc (sz); 245 if (p == NULL) 246 return FALSE; 247 *ptr = p; 248 } 249 memcpy (p, sec->contents, sz); 250 return TRUE; 251 252 default: 253 abort (); 254 } 255 } 256 257 /* 258 FUNCTION 259 bfd_cache_section_contents 260 261 SYNOPSIS 262 void bfd_cache_section_contents 263 (asection *sec, void *contents); 264 265 DESCRIPTION 266 Stash @var(contents) so any following reads of @var(sec) do 267 not need to decompress again. 268 */ 269 270 void 271 bfd_cache_section_contents (asection *sec, void *contents) 272 { 273 if (sec->compress_status == DECOMPRESS_SECTION_SIZED) 274 sec->compress_status = COMPRESS_SECTION_DONE; 275 sec->contents = contents; 276 sec->flags |= SEC_IN_MEMORY; 277 } 278 279 280 /* 281 FUNCTION 282 bfd_is_section_compressed 283 284 SYNOPSIS 285 bfd_boolean bfd_is_section_compressed 286 (bfd *abfd, asection *section); 287 288 DESCRIPTION 289 Return @code{TRUE} if @var{section} is compressed. 290 */ 291 292 bfd_boolean 293 bfd_is_section_compressed (bfd *abfd, sec_ptr sec) 294 { 295 bfd_byte compressed_buffer [12]; 296 unsigned int saved = sec->compress_status; 297 bfd_boolean compressed; 298 299 /* Don't decompress the section. */ 300 sec->compress_status = COMPRESS_SECTION_NONE; 301 302 /* Read the zlib header. In this case, it should be "ZLIB" followed 303 by the uncompressed section size, 8 bytes in big-endian order. */ 304 compressed = (bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12) 305 && CONST_STRNEQ ((char*) compressed_buffer, "ZLIB")); 306 307 /* Check for the pathalogical case of a debug string section that 308 contains the string ZLIB.... as the first entry. We assume that 309 no uncompressed .debug_str section would ever be big enough to 310 have the first byte of its (big-endian) size be non-zero. */ 311 if (compressed 312 && strcmp (sec->name, ".debug_str") == 0 313 && ISPRINT (compressed_buffer[4])) 314 compressed = FALSE; 315 316 /* Restore compress_status. */ 317 sec->compress_status = saved; 318 return compressed; 319 } 320 321 /* 322 FUNCTION 323 bfd_init_section_decompress_status 324 325 SYNOPSIS 326 bfd_boolean bfd_init_section_decompress_status 327 (bfd *abfd, asection *section); 328 329 DESCRIPTION 330 Record compressed section size, update section size with 331 decompressed size and set compress_status to 332 DECOMPRESS_SECTION_SIZED. 333 334 Return @code{FALSE} if the section is not a valid compressed 335 section or zlib is not installed on this machine. Otherwise, 336 return @code{TRUE}. 337 */ 338 339 bfd_boolean 340 bfd_init_section_decompress_status (bfd *abfd ATTRIBUTE_UNUSED, 341 sec_ptr sec ATTRIBUTE_UNUSED) 342 { 343 #ifndef HAVE_ZLIB_H 344 bfd_set_error (bfd_error_invalid_operation); 345 return FALSE; 346 #else 347 bfd_byte compressed_buffer [12]; 348 bfd_size_type uncompressed_size; 349 350 if (sec->rawsize != 0 351 || sec->contents != NULL 352 || sec->compress_status != COMPRESS_SECTION_NONE 353 || !bfd_get_section_contents (abfd, sec, compressed_buffer, 0, 12)) 354 { 355 bfd_set_error (bfd_error_invalid_operation); 356 return FALSE; 357 } 358 359 /* Read the zlib header. In this case, it should be "ZLIB" followed 360 by the uncompressed section size, 8 bytes in big-endian order. */ 361 if (! CONST_STRNEQ ((char*) compressed_buffer, "ZLIB")) 362 { 363 bfd_set_error (bfd_error_wrong_format); 364 return FALSE; 365 } 366 367 uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8; 368 uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8; 369 uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8; 370 uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8; 371 uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8; 372 uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8; 373 uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8; 374 uncompressed_size += compressed_buffer[11]; 375 376 sec->compressed_size = sec->size; 377 sec->size = uncompressed_size; 378 sec->compress_status = DECOMPRESS_SECTION_SIZED; 379 380 return TRUE; 381 #endif 382 } 383 384 /* 385 FUNCTION 386 bfd_init_section_compress_status 387 388 SYNOPSIS 389 bfd_boolean bfd_init_section_compress_status 390 (bfd *abfd, asection *section); 391 392 DESCRIPTION 393 If open for read, compress section, update section size with 394 compressed size and set compress_status to COMPRESS_SECTION_DONE. 395 396 Return @code{FALSE} if the section is not a valid compressed 397 section or zlib is not installed on this machine. Otherwise, 398 return @code{TRUE}. 399 */ 400 401 bfd_boolean 402 bfd_init_section_compress_status (bfd *abfd ATTRIBUTE_UNUSED, 403 sec_ptr sec ATTRIBUTE_UNUSED) 404 { 405 #ifndef HAVE_ZLIB_H 406 bfd_set_error (bfd_error_invalid_operation); 407 return FALSE; 408 #else 409 bfd_size_type uncompressed_size; 410 bfd_byte *uncompressed_buffer; 411 bfd_boolean ret; 412 413 /* Error if not opened for read. */ 414 if (abfd->direction != read_direction 415 || sec->size == 0 416 || sec->rawsize != 0 417 || sec->contents != NULL 418 || sec->compress_status != COMPRESS_SECTION_NONE) 419 { 420 bfd_set_error (bfd_error_invalid_operation); 421 return FALSE; 422 } 423 424 /* Read in the full section contents and compress it. */ 425 uncompressed_size = sec->size; 426 uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size); 427 if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer, 428 0, uncompressed_size)) 429 ret = FALSE; 430 else 431 ret = bfd_compress_section_contents (abfd, sec, 432 uncompressed_buffer, 433 uncompressed_size); 434 435 free (uncompressed_buffer); 436 return ret; 437 #endif 438 } 439
