1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
|
/* DWARF DWZ handling for GDB.
Copyright (C) 2003-2024 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "dwarf2/dwz.h"
#include "build-id.h"
#include "debuginfod-support.h"
#include "dwarf2/read.h"
#include "dwarf2/sect-names.h"
#include "filenames.h"
#include "gdb_bfd.h"
#include "gdbcore.h"
#include "gdbsupport/pathstuff.h"
#include "gdbsupport/scoped_fd.h"
#include "run-on-main-thread.h"
const char *
dwz_file::read_string (struct objfile *objfile, LONGEST str_offset)
{
str.read (objfile);
if (str.buffer == NULL)
error (_("DW_FORM_GNU_strp_alt used without .debug_str "
"section [in module %s]"),
bfd_get_filename (dwz_bfd.get ()));
if (str_offset >= str.size)
error (_("DW_FORM_GNU_strp_alt pointing outside of "
".debug_str section [in module %s]"),
bfd_get_filename (dwz_bfd.get ()));
gdb_assert (HOST_CHAR_BIT == 8);
if (str.buffer[str_offset] == '\0')
return NULL;
return (const char *) (str.buffer + str_offset);
}
/* A helper function to find the sections for a .dwz file. */
static void
locate_dwz_sections (struct objfile *objfile, bfd *abfd, asection *sectp,
dwz_file *dwz_file)
{
dwarf2_section_info *sect = nullptr;
/* Note that we only support the standard ELF names, because .dwz
is ELF-only (at the time of writing). */
if (dwarf2_elf_names.abbrev.matches (sectp->name))
sect = &dwz_file->abbrev;
else if (dwarf2_elf_names.info.matches (sectp->name))
sect = &dwz_file->info;
else if (dwarf2_elf_names.str.matches (sectp->name))
sect = &dwz_file->str;
else if (dwarf2_elf_names.line.matches (sectp->name))
sect = &dwz_file->line;
else if (dwarf2_elf_names.macro.matches (sectp->name))
sect = &dwz_file->macro;
else if (dwarf2_elf_names.gdb_index.matches (sectp->name))
sect = &dwz_file->gdb_index;
else if (dwarf2_elf_names.debug_names.matches (sectp->name))
sect = &dwz_file->debug_names;
else if (dwarf2_elf_names.types.matches (sectp->name))
sect = &dwz_file->types;
if (sect != nullptr)
{
sect->s.section = sectp;
sect->size = bfd_section_size (sectp);
sect->read (objfile);
}
}
/* Attempt to find a .dwz file (whose full path is represented by
FILENAME) in all of the specified debug file directories provided.
Return the equivalent gdb_bfd_ref_ptr of the .dwz file found, or
nullptr if it could not find anything. */
static gdb_bfd_ref_ptr
dwz_search_other_debugdirs (std::string &filename, bfd_byte *buildid,
size_t buildid_len)
{
/* Let's assume that the path represented by FILENAME has the
"/.dwz/" subpath in it. This is what (most) GNU/Linux
distributions do, anyway. */
size_t dwz_pos = filename.find ("/.dwz/");
if (dwz_pos == std::string::npos)
return nullptr;
/* This is an obvious assertion, but it's here more to educate
future readers of this code that FILENAME at DWZ_POS *must*
contain a directory separator. */
gdb_assert (IS_DIR_SEPARATOR (filename[dwz_pos]));
gdb_bfd_ref_ptr dwz_bfd;
std::vector<gdb::unique_xmalloc_ptr<char>> debugdir_vec
= dirnames_to_char_ptr_vec (debug_file_directory.c_str ());
for (const gdb::unique_xmalloc_ptr<char> &debugdir : debugdir_vec)
{
/* The idea is to iterate over the
debug file directories provided by the user and
replace the hard-coded path in the "filename" by each
debug-file-directory.
For example, suppose that filename is:
/usr/lib/debug/.dwz/foo.dwz
And suppose that we have "$HOME/bar" as the
debug-file-directory. We would then adjust filename
to look like:
$HOME/bar/.dwz/foo.dwz
which would hopefully allow us to find the alt debug
file. */
std::string ddir = debugdir.get ();
if (ddir.empty ())
continue;
/* Make sure the current debug-file-directory ends with a
directory separator. This is needed because, if FILENAME
contains something like "/usr/lib/abcde/.dwz/foo.dwz" and
DDIR is "/usr/lib/abc", then could wrongfully skip it
below. */
if (!IS_DIR_SEPARATOR (ddir.back ()))
ddir += SLASH_STRING;
/* Check whether the beginning of FILENAME is DDIR. If it is,
then we are dealing with a file which we already attempted to
open before, so we just skip it and continue processing the
remaining debug file directories. */
if (filename.size () > ddir.size ()
&& filename.compare (0, ddir.size (), ddir) == 0)
continue;
/* Replace FILENAME's default debug-file-directory with
DDIR. */
std::string new_filename = ddir + &filename[dwz_pos + 1];
dwz_bfd = gdb_bfd_open (new_filename.c_str (), gnutarget);
if (dwz_bfd == nullptr)
continue;
if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
{
dwz_bfd.reset (nullptr);
continue;
}
/* Found it. */
break;
}
return dwz_bfd;
}
/* See dwz.h. */
void
dwarf2_read_dwz_file (dwarf2_per_objfile *per_objfile)
{
bfd_size_type buildid_len_arg;
size_t buildid_len;
bfd_byte *buildid;
dwarf2_per_bfd *per_bfd = per_objfile->per_bfd;
/* This may query the user via the debuginfod support, so it may
only be run in the main thread. */
gdb_assert (is_main_thread ());
/* Set this early, so that on error it remains NULL. */
per_bfd->dwz_file.emplace (nullptr);
bfd_set_error (bfd_error_no_error);
gdb::unique_xmalloc_ptr<char> data
(bfd_get_alt_debug_link_info (per_bfd->obfd,
&buildid_len_arg, &buildid));
if (data == NULL)
{
if (bfd_get_error () == bfd_error_no_error)
return;
error (_("could not read '.gnu_debugaltlink' section: %s"),
bfd_errmsg (bfd_get_error ()));
}
gdb::unique_xmalloc_ptr<bfd_byte> buildid_holder (buildid);
buildid_len = (size_t) buildid_len_arg;
std::string filename = data.get ();
if (!IS_ABSOLUTE_PATH (filename.c_str ()))
{
gdb::unique_xmalloc_ptr<char> abs
= gdb_realpath (bfd_get_filename (per_bfd->obfd));
filename = ldirname (abs.get ()) + SLASH_STRING + filename;
}
/* First try the file name given in the section. If that doesn't
work, try to use the build-id instead. */
gdb_bfd_ref_ptr dwz_bfd (gdb_bfd_open (filename.c_str (), gnutarget));
if (dwz_bfd != NULL)
{
if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
dwz_bfd.reset (nullptr);
}
if (dwz_bfd == NULL)
dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid);
if (dwz_bfd == nullptr)
{
/* If the user has provided us with different
debug file directories, we can try them in order. */
dwz_bfd = dwz_search_other_debugdirs (filename, buildid, buildid_len);
}
if (dwz_bfd == nullptr)
{
gdb::unique_xmalloc_ptr<char> alt_filename;
const char *origname = bfd_get_filename (per_bfd->obfd);
scoped_fd fd (debuginfod_debuginfo_query (buildid,
buildid_len,
origname,
&alt_filename));
if (fd.get () >= 0)
{
/* File successfully retrieved from server. */
dwz_bfd = gdb_bfd_open (alt_filename.get (), gnutarget);
if (dwz_bfd == nullptr)
warning (_("File \"%s\" from debuginfod cannot be opened as bfd"),
alt_filename.get ());
else if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
dwz_bfd.reset (nullptr);
}
}
if (dwz_bfd == NULL)
error (_("could not find '.gnu_debugaltlink' file for %s"),
bfd_get_filename (per_bfd->obfd));
std::unique_ptr<struct dwz_file> result
(new struct dwz_file (std::move (dwz_bfd)));
for (asection *sec : gdb_bfd_sections (result->dwz_bfd))
locate_dwz_sections (per_objfile->objfile, result->dwz_bfd.get (),
sec, result.get ());
gdb_bfd_record_inclusion (per_bfd->obfd, result->dwz_bfd.get ());
bfd_cache_close (result->dwz_bfd.get ());
per_bfd->dwz_file = std::move (result);
}
/* See dwz.h. */
struct dwz_file *
dwarf2_get_dwz_file (dwarf2_per_bfd *per_bfd, bool require)
{
gdb_assert (!require || per_bfd->dwz_file.has_value ());
dwz_file *result = nullptr;
if (per_bfd->dwz_file.has_value ())
{
result = per_bfd->dwz_file->get ();
if (require && result == nullptr)
error (_("could not read '.gnu_debugaltlink' section"));
}
return result;
}
|