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
decompress_contents(bfd_byte * compressed_buffer,bfd_size_type compressed_size,bfd_byte * uncompressed_buffer,bfd_size_type uncompressed_size)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
bfd_compress_section_contents(bfd * abfd ATTRIBUTE_UNUSED,sec_ptr sec ATTRIBUTE_UNUSED,bfd_byte * uncompressed_buffer ATTRIBUTE_UNUSED,bfd_size_type uncompressed_size ATTRIBUTE_UNUSED)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
bfd_get_full_section_contents(bfd * abfd,sec_ptr sec,bfd_byte ** ptr)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
bfd_cache_section_contents(asection * sec,void * contents)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
bfd_is_section_compressed(bfd * abfd,sec_ptr sec)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
bfd_init_section_decompress_status(bfd * abfd ATTRIBUTE_UNUSED,sec_ptr sec ATTRIBUTE_UNUSED)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
bfd_init_section_compress_status(bfd * abfd ATTRIBUTE_UNUSED,sec_ptr sec ATTRIBUTE_UNUSED)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