1 /* Read MiniDebugInfo data from an objfile.
3 Copyright (C) 2012-2022 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/>. */
29 /* We stash a reference to the .gnu_debugdata BFD on the enclosing
31 static const registry
<bfd
>::key
<gdb_bfd_ref_ptr
> gnu_debug_key
;
35 /* Allocator function for LZMA. */
38 alloc_lzma (void *opaque
, size_t nmemb
, size_t size
)
40 return xmalloc (nmemb
* size
);
43 /* Free function for LZMA. */
46 free_lzma (void *opaque
, void *ptr
)
51 /* The allocator object for LZMA. Note that 'gdb_lzma_allocator'
52 cannot be const due to the lzma library function prototypes. */
54 static lzma_allocator gdb_lzma_allocator
= { alloc_lzma
, free_lzma
, NULL
};
56 /* Custom bfd_openr_iovec implementation to read compressed data from
57 a section. This keeps only the last decompressed block in memory
58 to allow larger data without using to much memory. */
60 struct gdb_lzma_stream
62 /* Section of input BFD from which we are decoding data. */
65 /* lzma library decompression state. */
68 /* Currently decoded block. */
69 bfd_size_type data_start
;
70 bfd_size_type data_end
;
74 /* bfd_openr_iovec OPEN_P implementation for
75 find_separate_debug_file_in_section. OPEN_CLOSURE is 'asection *'
76 of the section to decompress.
78 Return 'struct gdb_lzma_stream *' must be freed by caller by xfree,
79 together with its INDEX lzma data. */
82 lzma_open (struct bfd
*nbfd
, void *open_closure
)
84 asection
*section
= (asection
*) open_closure
;
85 bfd_size_type size
, offset
;
86 lzma_stream_flags options
;
87 gdb_byte footer
[LZMA_STREAM_HEADER_SIZE
];
90 uint64_t memlimit
= UINT64_MAX
;
91 struct gdb_lzma_stream
*lstream
;
94 size
= bfd_section_size (section
);
95 offset
= section
->filepos
+ size
- LZMA_STREAM_HEADER_SIZE
;
96 if (size
< LZMA_STREAM_HEADER_SIZE
97 || bfd_seek (section
->owner
, offset
, SEEK_SET
) != 0
98 || bfd_bread (footer
, LZMA_STREAM_HEADER_SIZE
, section
->owner
)
99 != LZMA_STREAM_HEADER_SIZE
100 || lzma_stream_footer_decode (&options
, footer
) != LZMA_OK
101 || offset
< options
.backward_size
)
103 bfd_set_error (bfd_error_wrong_format
);
107 offset
-= options
.backward_size
;
108 indexdata
= (gdb_byte
*) xmalloc (options
.backward_size
);
111 if (bfd_seek (section
->owner
, offset
, SEEK_SET
) != 0
112 || bfd_bread (indexdata
, options
.backward_size
, section
->owner
)
113 != options
.backward_size
114 || lzma_index_buffer_decode (&index
, &memlimit
, &gdb_lzma_allocator
,
115 indexdata
, &pos
, options
.backward_size
)
117 || lzma_index_size (index
) != options
.backward_size
)
120 bfd_set_error (bfd_error_wrong_format
);
125 lstream
= XCNEW (struct gdb_lzma_stream
);
126 lstream
->section
= section
;
127 lstream
->index
= index
;
132 /* bfd_openr_iovec PREAD_P implementation for
133 find_separate_debug_file_in_section. Passed STREAM
134 is 'struct gdb_lzma_stream *'. */
137 lzma_pread (struct bfd
*nbfd
, void *stream
, void *buf
, file_ptr nbytes
,
140 struct gdb_lzma_stream
*lstream
= (struct gdb_lzma_stream
*) stream
;
141 bfd_size_type chunk_size
;
142 lzma_index_iter iter
;
143 gdb_byte
*compressed
, *uncompressed
;
144 file_ptr block_offset
;
145 lzma_filter filters
[LZMA_FILTERS_MAX
+ 1];
147 size_t compressed_pos
, uncompressed_pos
;
153 if (lstream
->data
== NULL
154 || lstream
->data_start
> offset
|| offset
>= lstream
->data_end
)
156 asection
*section
= lstream
->section
;
158 lzma_index_iter_init (&iter
, lstream
->index
);
159 if (lzma_index_iter_locate (&iter
, offset
))
162 compressed
= (gdb_byte
*) xmalloc (iter
.block
.total_size
);
163 block_offset
= section
->filepos
+ iter
.block
.compressed_file_offset
;
164 if (bfd_seek (section
->owner
, block_offset
, SEEK_SET
) != 0
165 || bfd_bread (compressed
, iter
.block
.total_size
, section
->owner
)
166 != iter
.block
.total_size
)
172 uncompressed
= (gdb_byte
*) xmalloc (iter
.block
.uncompressed_size
);
174 memset (&block
, 0, sizeof (block
));
175 block
.filters
= filters
;
176 block
.header_size
= lzma_block_header_size_decode (compressed
[0]);
177 if (lzma_block_header_decode (&block
, &gdb_lzma_allocator
, compressed
)
181 xfree (uncompressed
);
185 compressed_pos
= block
.header_size
;
186 uncompressed_pos
= 0;
187 if (lzma_block_buffer_decode (&block
, &gdb_lzma_allocator
,
188 compressed
, &compressed_pos
,
189 iter
.block
.total_size
,
190 uncompressed
, &uncompressed_pos
,
191 iter
.block
.uncompressed_size
)
195 xfree (uncompressed
);
201 xfree (lstream
->data
);
202 lstream
->data
= uncompressed
;
203 lstream
->data_start
= iter
.block
.uncompressed_file_offset
;
204 lstream
->data_end
= (iter
.block
.uncompressed_file_offset
205 + iter
.block
.uncompressed_size
);
208 chunk_size
= std::min (nbytes
, (file_ptr
) lstream
->data_end
- offset
);
209 memcpy (buf
, lstream
->data
+ offset
- lstream
->data_start
, chunk_size
);
210 buf
= (gdb_byte
*) buf
+ chunk_size
;
211 offset
+= chunk_size
;
212 nbytes
-= chunk_size
;
219 /* bfd_openr_iovec CLOSE_P implementation for
220 find_separate_debug_file_in_section. Passed STREAM
221 is 'struct gdb_lzma_stream *'. */
224 lzma_close (struct bfd
*nbfd
,
227 struct gdb_lzma_stream
*lstream
= (struct gdb_lzma_stream
*) stream
;
229 lzma_index_end (lstream
->index
, &gdb_lzma_allocator
);
230 xfree (lstream
->data
);
233 /* Zero means success. */
237 /* bfd_openr_iovec STAT_P implementation for
238 find_separate_debug_file_in_section. Passed STREAM
239 is 'struct gdb_lzma_stream *'. */
242 lzma_stat (struct bfd
*abfd
,
246 struct gdb_lzma_stream
*lstream
= (struct gdb_lzma_stream
*) stream
;
248 memset (sb
, 0, sizeof (struct stat
));
249 sb
->st_size
= lzma_index_uncompressed_size (lstream
->index
);
253 #endif /* HAVE_LIBLZMA */
255 /* This looks for a xz compressed separate debug info object file embedded
256 in a section called .gnu_debugdata. See
257 http://fedoraproject.org/wiki/Features/MiniDebugInfo
258 or the "Separate Debug Sections" of the manual for details.
259 If we find one we create a iovec based bfd that decompresses the
260 object data on demand. If we don't find one, return NULL. */
263 find_separate_debug_file_in_section (struct objfile
*objfile
)
266 gdb_bfd_ref_ptr abfd
;
268 if (objfile
->obfd
== NULL
)
271 section
= bfd_get_section_by_name (objfile
->obfd
.get (), ".gnu_debugdata");
276 gdb_bfd_ref_ptr
*shared
= gnu_debug_key
.get (objfile
->obfd
.get ());
277 if (shared
!= nullptr)
280 std::string filename
= string_printf (_(".gnu_debugdata for %s"),
281 objfile_name (objfile
));
283 abfd
= gdb_bfd_openr_iovec (filename
.c_str (), gnutarget
, lzma_open
,
284 section
, lzma_pread
, lzma_close
, lzma_stat
);
288 if (!bfd_check_format (abfd
.get (), bfd_object
))
290 warning (_("Cannot parse .gnu_debugdata section; not a BFD object"));
294 gnu_debug_key
.emplace (objfile
->obfd
.get (), abfd
);
297 warning (_("Cannot parse .gnu_debugdata section; LZMA support was "
298 "disabled at compile time"));
299 #endif /* !HAVE_LIBLZMA */