1 /* Read MiniDebugInfo data from an objfile.
3 Copyright (C) 2012-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
30 /* Allocator function for LZMA. */
33 alloc_lzma (void *opaque
, size_t nmemb
, size_t size
)
35 return xmalloc (nmemb
* size
);
38 /* Free function for LZMA. */
41 free_lzma (void *opaque
, void *ptr
)
46 /* The allocator object for LZMA. Note that 'gdb_lzma_allocator'
47 cannot be const due to the lzma library function prototypes. */
49 static lzma_allocator gdb_lzma_allocator
= { alloc_lzma
, free_lzma
, NULL
};
51 /* Custom bfd_openr_iovec implementation to read compressed data from
52 a section. This keeps only the last decompressed block in memory
53 to allow larger data without using to much memory. */
57 /* Section of input BFD from which we are decoding data. */
60 /* lzma library decompression state. */
63 /* Currently decoded block. */
64 bfd_size_type data_start
;
65 bfd_size_type data_end
;
69 /* bfd_openr_iovec OPEN_P implementation for
70 find_separate_debug_file_in_section. OPEN_CLOSURE is 'asection *'
71 of the section to decompress.
73 Return 'struct lzma_stream *' must be freed by caller by xfree, together
74 with its INDEX lzma data. */
77 lzma_open (struct bfd
*nbfd
, void *open_closure
)
79 asection
*section
= open_closure
;
80 bfd_size_type size
, offset
;
81 lzma_stream_flags options
;
82 gdb_byte footer
[LZMA_STREAM_HEADER_SIZE
];
86 uint64_t memlimit
= UINT64_MAX
;
87 struct lzma_stream
*lstream
;
90 size
= bfd_get_section_size (section
);
91 offset
= section
->filepos
+ size
- LZMA_STREAM_HEADER_SIZE
;
92 if (size
< LZMA_STREAM_HEADER_SIZE
93 || bfd_seek (section
->owner
, offset
, SEEK_SET
) != 0
94 || bfd_bread (footer
, LZMA_STREAM_HEADER_SIZE
, section
->owner
)
95 != LZMA_STREAM_HEADER_SIZE
96 || lzma_stream_footer_decode (&options
, footer
) != LZMA_OK
97 || offset
< options
.backward_size
)
99 bfd_set_error (bfd_error_wrong_format
);
103 offset
-= options
.backward_size
;
104 indexdata
= xmalloc (options
.backward_size
);
107 if (bfd_seek (section
->owner
, offset
, SEEK_SET
) != 0
108 || bfd_bread (indexdata
, options
.backward_size
, section
->owner
)
109 != options
.backward_size
110 || lzma_index_buffer_decode (&index
, &memlimit
, &gdb_lzma_allocator
,
111 indexdata
, &pos
, options
.backward_size
)
113 || lzma_index_size (index
) != options
.backward_size
)
116 bfd_set_error (bfd_error_wrong_format
);
121 lstream
= xzalloc (sizeof (struct lzma_stream
));
122 lstream
->section
= section
;
123 lstream
->index
= index
;
128 /* bfd_openr_iovec PREAD_P implementation for
129 find_separate_debug_file_in_section. Passed STREAM
130 is 'struct lzma_stream *'. */
133 lzma_pread (struct bfd
*nbfd
, void *stream
, void *buf
, file_ptr nbytes
,
136 struct lzma_stream
*lstream
= stream
;
137 bfd_size_type chunk_size
;
138 lzma_index_iter iter
;
139 gdb_byte
*compressed
, *uncompressed
;
140 file_ptr block_offset
;
141 lzma_filter filters
[LZMA_FILTERS_MAX
+ 1];
143 size_t compressed_pos
, uncompressed_pos
;
149 if (lstream
->data
== NULL
150 || lstream
->data_start
> offset
|| offset
>= lstream
->data_end
)
152 asection
*section
= lstream
->section
;
154 lzma_index_iter_init (&iter
, lstream
->index
);
155 if (lzma_index_iter_locate (&iter
, offset
))
158 compressed
= xmalloc (iter
.block
.total_size
);
159 block_offset
= section
->filepos
+ iter
.block
.compressed_file_offset
;
160 if (bfd_seek (section
->owner
, block_offset
, SEEK_SET
) != 0
161 || bfd_bread (compressed
, iter
.block
.total_size
, section
->owner
)
162 != iter
.block
.total_size
)
168 uncompressed
= xmalloc (iter
.block
.uncompressed_size
);
170 memset (&block
, 0, sizeof (block
));
171 block
.filters
= filters
;
172 block
.header_size
= lzma_block_header_size_decode (compressed
[0]);
173 if (lzma_block_header_decode (&block
, &gdb_lzma_allocator
, compressed
)
177 xfree (uncompressed
);
181 compressed_pos
= block
.header_size
;
182 uncompressed_pos
= 0;
183 if (lzma_block_buffer_decode (&block
, &gdb_lzma_allocator
,
184 compressed
, &compressed_pos
,
185 iter
.block
.total_size
,
186 uncompressed
, &uncompressed_pos
,
187 iter
.block
.uncompressed_size
)
191 xfree (uncompressed
);
197 xfree (lstream
->data
);
198 lstream
->data
= uncompressed
;
199 lstream
->data_start
= iter
.block
.uncompressed_file_offset
;
200 lstream
->data_end
= (iter
.block
.uncompressed_file_offset
201 + iter
.block
.uncompressed_size
);
204 chunk_size
= min (nbytes
, lstream
->data_end
- offset
);
205 memcpy (buf
, lstream
->data
+ offset
- lstream
->data_start
, chunk_size
);
206 buf
= (gdb_byte
*) buf
+ chunk_size
;
207 offset
+= chunk_size
;
208 nbytes
-= chunk_size
;
215 /* bfd_openr_iovec CLOSE_P implementation for
216 find_separate_debug_file_in_section. Passed STREAM
217 is 'struct lzma_stream *'. */
220 lzma_close (struct bfd
*nbfd
,
223 struct lzma_stream
*lstream
= stream
;
225 lzma_index_end (lstream
->index
, &gdb_lzma_allocator
);
226 xfree (lstream
->data
);
229 /* Zero means success. */
233 /* bfd_openr_iovec STAT_P implementation for
234 find_separate_debug_file_in_section. Passed STREAM
235 is 'struct lzma_stream *'. */
238 lzma_stat (struct bfd
*abfd
,
242 struct lzma_stream
*lstream
= stream
;
244 sb
->st_size
= lzma_index_uncompressed_size (lstream
->index
);
248 #endif /* HAVE_LIBLZMA */
250 /* This looks for a xz compressed separate debug info object file embedded
251 in a section called .gnu_debugdata. See
252 http://fedoraproject.org/wiki/Features/MiniDebugInfo
253 or the "Separate Debug Sections" of the manual for details.
254 If we find one we create a iovec based bfd that decompresses the
255 object data on demand. If we don't find one, return NULL. */
258 find_separate_debug_file_in_section (struct objfile
*objfile
)
263 if (objfile
->obfd
== NULL
)
266 section
= bfd_get_section_by_name (objfile
->obfd
, ".gnu_debugdata");
271 abfd
= gdb_bfd_openr_iovec (objfile_name (objfile
), gnutarget
, lzma_open
,
272 section
, lzma_pread
, lzma_close
, lzma_stat
);
276 if (!bfd_check_format (abfd
, bfd_object
))
278 warning (_("Cannot parse .gnu_debugdata section; not a BFD object"));
279 gdb_bfd_unref (abfd
);
283 warning (_("Cannot parse .gnu_debugdata section; LZMA support was "
284 "disabled at compile time"));
286 #endif /* !HAVE_LIBLZMA */