1 /* Compressed section support (intended for debug sections).
2 Copyright (C) 2008-2015 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
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.
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.
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. */
25 #include "safe-ctype.h"
27 #define MAX_COMPRESSION_HEADER_SIZE 24
30 decompress_contents (bfd_byte *compressed_buffer,
31 bfd_size_type compressed_size,
32 bfd_byte *uncompressed_buffer,
33 bfd_size_type uncompressed_size)
38 /* It is possible the section consists of several compressed
39 buffers concatenated together, so we uncompress in a loop. */
43 strm.avail_in = compressed_size - 12;
44 strm.next_in = (Bytef*) compressed_buffer + 12;
45 strm.avail_out = uncompressed_size;
47 BFD_ASSERT (Z_OK == 0);
48 rc = inflateInit (&strm);
49 while (strm.avail_in > 0 && strm.avail_out > 0)
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)
58 rc = inflateReset (&strm);
60 rc |= inflateEnd (&strm);
61 return rc == Z_OK && strm.avail_out == 0;
64 /* Compress data of the size specified in @var{uncompressed_size}
65 and pointed to by @var{uncompressed_buffer} using zlib and store
66 as the contents field. This function assumes the contents
67 field was allocated using bfd_malloc() or equivalent.
69 Return the uncompressed size if the full section contents is
70 compressed successfully. Otherwise return 0. */
73 bfd_compress_section_contents (bfd *abfd, sec_ptr sec,
74 bfd_byte *uncompressed_buffer,
75 bfd_size_type uncompressed_size)
77 uLong compressed_size;
79 bfd_size_type buffer_size;
80 bfd_boolean decompress;
81 #if defined(__GNUC__) && GCC_VERSION < 4007
82 /* Work around a GCC uninitialized warning bug fixed in GCC 4.7. */
87 int orig_compression_header_size;
88 int compression_header_size
89 = bfd_get_compression_header_size (abfd, NULL);
90 bfd_boolean compressed
91 = bfd_is_section_compressed_with_header (abfd, sec,
92 &orig_compression_header_size);
96 /* We shouldn't decompress unsupported compressed section. */
97 if (orig_compression_header_size < 0)
100 /* Different compression schemes. Just move the compressed section
101 contents to the right position. */
102 if (orig_compression_header_size == 0)
104 /* Convert it from .zdebug* section. Get the uncompressed
106 zlib_size = uncompressed_size;
107 compressed_size = zlib_size + compression_header_size;
108 uncompressed_size = bfd_getb64 (uncompressed_buffer + 4);
112 /* Convert it to .zdebug* section. */
113 zlib_size = uncompressed_size - orig_compression_header_size;
114 compressed_size = zlib_size;
118 compressed_size = compressBound (uncompressed_size) + 12;
120 /* When converting from .zdebug* section, uncompress if it leads to
123 && orig_compression_header_size == 0
124 && compressed_size > uncompressed_size)
127 buffer_size = uncompressed_size;
132 buffer_size = compressed_size + compression_header_size;
134 buffer = (bfd_byte *) bfd_alloc (abfd, buffer_size);
140 sec->size = uncompressed_size;
143 if (!decompress_contents (uncompressed_buffer, zlib_size,
144 buffer, uncompressed_size))
146 bfd_set_error (bfd_error_bad_value);
147 bfd_release (abfd, buffer);
150 free (uncompressed_buffer);
151 sec->contents = buffer;
152 sec->compress_status = COMPRESS_SECTION_DONE;
153 return uncompressed_size;
157 bfd_update_compression_header (abfd, buffer, sec);
158 memmove (buffer + compression_header_size,
159 uncompressed_buffer + orig_compression_header_size,
165 bfd_size_type size = uncompressed_size;
166 int header_size = 12 + compression_header_size;
167 if (compress ((Bytef*) buffer + header_size,
169 (const Bytef*) uncompressed_buffer,
170 uncompressed_size) != Z_OK)
172 bfd_release (abfd, buffer);
173 bfd_set_error (bfd_error_bad_value);
177 compressed_size += header_size;
178 /* PR binutils/18087: If compression didn't make the section smaller,
179 just keep it uncompressed. */
180 if (compressed_size < uncompressed_size)
182 bfd_update_compression_header (abfd, buffer, sec);
184 /* Write the zlib header. In this case, it should be "ZLIB"
185 followed by the uncompressed section size, 8 bytes in
187 memcpy (buffer + compression_header_size, "ZLIB", 4);
188 bfd_putb64 (size, buffer + compression_header_size + 4);
192 /* NOTE: There is a small memory leak here since
193 uncompressed_buffer is malloced and won't be freed. */
194 bfd_release (abfd, buffer);
195 sec->contents = uncompressed_buffer;
196 sec->compress_status = COMPRESS_SECTION_NONE;
197 return uncompressed_size;
201 free (uncompressed_buffer);
202 sec->contents = buffer;
203 sec->size = compressed_size;
204 sec->compress_status = COMPRESS_SECTION_DONE;
206 return uncompressed_size;
211 bfd_get_full_section_contents
214 bfd_boolean bfd_get_full_section_contents
215 (bfd *abfd, asection *section, bfd_byte **ptr);
218 Read all data from @var{section} in BFD @var{abfd}, decompress
219 if needed, and store in @var{*ptr}. If @var{*ptr} is NULL,
220 return @var{*ptr} with memory malloc'd by this function.
222 Return @code{TRUE} if the full section contents is retrieved
223 successfully. If the section has no contents then this function
224 returns @code{TRUE} but @var{*ptr} is set to NULL.
228 bfd_get_full_section_contents (bfd *abfd, sec_ptr sec, bfd_byte **ptr)
233 bfd_size_type save_size;
234 bfd_size_type save_rawsize;
235 bfd_byte *compressed_buffer;
236 unsigned int compression_header_size;
238 if (abfd->direction != write_direction && sec->rawsize != 0)
248 switch (sec->compress_status)
250 case COMPRESS_SECTION_NONE:
253 p = (bfd_byte *) bfd_malloc (sz);
258 if (!bfd_get_section_contents (abfd, sec, p, 0, sz))
267 case DECOMPRESS_SECTION_SIZED:
268 /* Read in the full compressed section contents. */
269 compressed_buffer = (bfd_byte *) bfd_malloc (sec->compressed_size);
270 if (compressed_buffer == NULL)
272 save_rawsize = sec->rawsize;
273 save_size = sec->size;
274 /* Clear rawsize, set size to compressed size and set compress_status
275 to COMPRESS_SECTION_NONE. If the compressed size is bigger than
276 the uncompressed size, bfd_get_section_contents will fail. */
278 sec->size = sec->compressed_size;
279 sec->compress_status = COMPRESS_SECTION_NONE;
280 ret = bfd_get_section_contents (abfd, sec, compressed_buffer,
281 0, sec->compressed_size);
282 /* Restore rawsize and size. */
283 sec->rawsize = save_rawsize;
284 sec->size = save_size;
285 sec->compress_status = DECOMPRESS_SECTION_SIZED;
287 goto fail_compressed;
290 p = (bfd_byte *) bfd_malloc (sz);
292 goto fail_compressed;
294 compression_header_size = bfd_get_compression_header_size (abfd, sec);
295 if (!decompress_contents (compressed_buffer + compression_header_size,
296 sec->compressed_size, p, sz))
298 bfd_set_error (bfd_error_bad_value);
302 free (compressed_buffer);
306 free (compressed_buffer);
310 case COMPRESS_SECTION_DONE:
311 if (sec->contents == NULL)
315 p = (bfd_byte *) bfd_malloc (sz);
320 /* PR 17512; file: 5bc29788. */
321 if (p != sec->contents)
322 memcpy (p, sec->contents, sz);
332 bfd_cache_section_contents
335 void bfd_cache_section_contents
336 (asection *sec, void *contents);
339 Stash @var(contents) so any following reads of @var(sec) do
340 not need to decompress again.
344 bfd_cache_section_contents (asection *sec, void *contents)
346 if (sec->compress_status == DECOMPRESS_SECTION_SIZED)
347 sec->compress_status = COMPRESS_SECTION_DONE;
348 sec->contents = contents;
349 sec->flags |= SEC_IN_MEMORY;
354 bfd_is_section_compressed_with_header
357 bfd_boolean bfd_is_section_compressed_with_header
358 (bfd *abfd, asection *section,
359 int *compression_header_size_p);
362 Return @code{TRUE} if @var{section} is compressed. Compression
363 header size is returned in @var{compression_header_size_p}. If
364 compression is unsupported, compression header size is returned
369 bfd_is_section_compressed_with_header (bfd *abfd, sec_ptr sec,
370 int *compression_header_size_p)
372 bfd_byte header[MAX_COMPRESSION_HEADER_SIZE + 12];
373 int compression_header_size;
374 int header_size = 12;
375 unsigned int saved = sec->compress_status;
376 bfd_boolean compressed;
378 compression_header_size = bfd_get_compression_header_size (abfd, sec);
379 if (compression_header_size > MAX_COMPRESSION_HEADER_SIZE)
381 header_size += compression_header_size;
383 /* Don't decompress the section. */
384 sec->compress_status = COMPRESS_SECTION_NONE;
386 /* Read the zlib header. In this case, it should be "ZLIB" followed
387 by the uncompressed section size, 8 bytes in big-endian order. */
388 compressed = bfd_get_section_contents (abfd, sec, header, 0,
390 && CONST_STRNEQ ((char*) header + compression_header_size,
395 if (compression_header_size != 0)
397 bfd_size_type uncompressed_size
398 = bfd_getb64 ((bfd_byte *) header
399 + compression_header_size + 4);
400 if (!bfd_check_compression_header (abfd, header, sec,
402 compression_header_size = -1;
404 /* Check for the pathalogical case of a debug string section that
405 contains the string ZLIB.... as the first entry. We assume that
406 no uncompressed .debug_str section would ever be big enough to
407 have the first byte of its (big-endian) size be non-zero. */
408 else if (strcmp (sec->name, ".debug_str") == 0
409 && ISPRINT (header[compression_header_size + 4]))
413 /* Restore compress_status. */
414 sec->compress_status = saved;
415 *compression_header_size_p = compression_header_size;
421 bfd_is_section_compressed
424 bfd_boolean bfd_is_section_compressed
425 (bfd *abfd, asection *section);
428 Return @code{TRUE} if @var{section} is compressed.
432 bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
434 int compression_header_size;
435 return (bfd_is_section_compressed_with_header (abfd, sec,
436 &compression_header_size)
437 && compression_header_size >= 0);
442 bfd_init_section_decompress_status
445 bfd_boolean bfd_init_section_decompress_status
446 (bfd *abfd, asection *section);
449 Record compressed section size, update section size with
450 decompressed size and set compress_status to
451 DECOMPRESS_SECTION_SIZED.
453 Return @code{FALSE} if the section is not a valid compressed
454 section. Otherwise, return @code{TRUE}.
458 bfd_init_section_decompress_status (bfd *abfd, sec_ptr sec)
460 bfd_byte header[MAX_COMPRESSION_HEADER_SIZE + 12];
461 int compression_header_size;
462 int header_size = 12;
463 bfd_size_type uncompressed_size;
465 compression_header_size = bfd_get_compression_header_size (abfd, sec);
466 if (compression_header_size > MAX_COMPRESSION_HEADER_SIZE)
468 header_size += compression_header_size;
470 if (sec->rawsize != 0
471 || sec->contents != NULL
472 || sec->compress_status != COMPRESS_SECTION_NONE
473 || !bfd_get_section_contents (abfd, sec, header, 0, header_size))
475 bfd_set_error (bfd_error_invalid_operation);
479 /* Read the zlib header. In this case, it should be "ZLIB" followed
480 by the uncompressed section size, 8 bytes in big-endian order. */
481 if (! CONST_STRNEQ ((char*) header + compression_header_size, "ZLIB"))
483 bfd_set_error (bfd_error_wrong_format);
487 uncompressed_size = bfd_getb64 (header + compression_header_size + 4);
488 if (compression_header_size != 0
489 && !bfd_check_compression_header (abfd, header, sec,
492 bfd_set_error (bfd_error_wrong_format);
495 sec->compressed_size = sec->size;
496 sec->size = uncompressed_size;
497 sec->compress_status = DECOMPRESS_SECTION_SIZED;
504 bfd_init_section_compress_status
507 bfd_boolean bfd_init_section_compress_status
508 (bfd *abfd, asection *section);
511 If open for read, compress section, update section size with
512 compressed size and set compress_status to COMPRESS_SECTION_DONE.
514 Return @code{FALSE} if the section is not a valid compressed
515 section. Otherwise, return @code{TRUE}.
519 bfd_init_section_compress_status (bfd *abfd, sec_ptr sec)
521 bfd_size_type uncompressed_size;
522 bfd_byte *uncompressed_buffer;
525 /* Error if not opened for read. */
526 if (abfd->direction != read_direction
529 || sec->contents != NULL
530 || sec->compress_status != COMPRESS_SECTION_NONE)
532 bfd_set_error (bfd_error_invalid_operation);
536 /* Read in the full section contents and compress it. */
537 uncompressed_size = sec->size;
538 uncompressed_buffer = (bfd_byte *) bfd_malloc (uncompressed_size);
539 if (!bfd_get_section_contents (abfd, sec, uncompressed_buffer,
540 0, uncompressed_size))
544 uncompressed_size = bfd_compress_section_contents (abfd, sec,
547 ret = uncompressed_size != 0;