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build-id.c
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1/* build-id-related functions.
2
3 Copyright (C) 1991-2023 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
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.
11
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.
16
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/>. */
19
20#include "defs.h"
21#include "bfd.h"
22#include "gdb_bfd.h"
23#include "build-id.h"
24#include "gdbsupport/gdb_vecs.h"
25#include "symfile.h"
26#include "objfiles.h"
27#include "filenames.h"
28#include "gdbcore.h"
29
30/* See build-id.h. */
31
32const struct bfd_build_id *
34{
35 if (!bfd_check_format (abfd, bfd_object)
36 && !bfd_check_format (abfd, bfd_core))
37 return NULL;
38
39 if (abfd->build_id != NULL)
40 return abfd->build_id;
41
42 /* No build-id */
43 return NULL;
44}
45
46/* See build-id.h. */
47
48int
49build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check)
50{
51 const struct bfd_build_id *found;
52 int retval = 0;
53
54 found = build_id_bfd_get (abfd);
55
56 if (found == NULL)
57 warning (_("File \"%s\" has no build-id, file skipped"),
58 bfd_get_filename (abfd));
59 else if (found->size != check_len
60 || memcmp (found->data, check, found->size) != 0)
61 warning (_("File \"%s\" has a different build-id, file skipped"),
62 bfd_get_filename (abfd));
63 else
64 retval = 1;
65
66 return retval;
67}
68
69/* Helper for build_id_to_debug_bfd. LINK is a path to a potential
70 build-id-based separate debug file, potentially a symlink to the real file.
71 If the file exists and matches BUILD_ID, return a BFD reference to it. */
72
73static gdb_bfd_ref_ptr
74build_id_to_debug_bfd_1 (const std::string &link, size_t build_id_len,
75 const bfd_byte *build_id)
76{
78 {
79 gdb_printf (gdb_stdlog, _(" Trying %s..."), link.c_str ());
81 }
82
83 /* lrealpath() is expensive even for the usually non-existent files. */
84 gdb::unique_xmalloc_ptr<char> filename_holder;
85 const char *filename = nullptr;
86 if (startswith (link, TARGET_SYSROOT_PREFIX))
87 filename = link.c_str ();
88 else if (access (link.c_str (), F_OK) == 0)
89 {
90 filename_holder.reset (lrealpath (link.c_str ()));
91 filename = filename_holder.get ();
92 }
93
94 if (filename == NULL)
95 {
98 _(" no, unable to compute real path\n"));
99
100 return {};
101 }
102
103 /* We expect to be silent on the non-existing files. */
104 gdb_bfd_ref_ptr debug_bfd = gdb_bfd_open (filename, gnutarget);
105
106 if (debug_bfd == NULL)
107 {
109 gdb_printf (gdb_stdlog, _(" no, unable to open.\n"));
110
111 return {};
112 }
113
114 if (!build_id_verify (debug_bfd.get(), build_id_len, build_id))
115 {
117 gdb_printf (gdb_stdlog, _(" no, build-id does not match.\n"));
118
119 return {};
120 }
121
123 gdb_printf (gdb_stdlog, _(" yes!\n"));
124
125 return debug_bfd;
126}
127
128/* Common code for finding BFDs of a given build-id. This function
129 works with both debuginfo files (SUFFIX == ".debug") and executable
130 files (SUFFIX == ""). */
131
132static gdb_bfd_ref_ptr
133build_id_to_bfd_suffix (size_t build_id_len, const bfd_byte *build_id,
134 const char *suffix)
135{
136 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
137 cause "/.build-id/..." lookups. */
138
139 std::vector<gdb::unique_xmalloc_ptr<char>> debugdir_vec
140 = dirnames_to_char_ptr_vec (debug_file_directory.c_str ());
141
142 for (const gdb::unique_xmalloc_ptr<char> &debugdir : debugdir_vec)
143 {
144 const gdb_byte *data = build_id;
145 size_t size = build_id_len;
146
147 /* Compute where the file named after the build-id would be.
148
149 If debugdir is "/usr/lib/debug" and the build-id is abcdef, this will
150 give "/usr/lib/debug/.build-id/ab/cdef.debug". */
151 std::string link = debugdir.get ();
152 link += "/.build-id/";
153
154 if (size > 0)
155 {
156 size--;
157 string_appendf (link, "%02x/", (unsigned) *data++);
158 }
159
160 while (size-- > 0)
161 string_appendf (link, "%02x", (unsigned) *data++);
162
163 link += suffix;
164
165 gdb_bfd_ref_ptr debug_bfd
166 = build_id_to_debug_bfd_1 (link, build_id_len, build_id);
167 if (debug_bfd != NULL)
168 return debug_bfd;
169
170 /* Try to look under the sysroot as well. If the sysroot is
171 "/the/sysroot", it will give
172 "/the/sysroot/usr/lib/debug/.build-id/ab/cdef.debug". */
173
174 if (!gdb_sysroot.empty ())
175 {
176 link = gdb_sysroot + link;
177 debug_bfd = build_id_to_debug_bfd_1 (link, build_id_len, build_id);
178 if (debug_bfd != NULL)
179 return debug_bfd;
180 }
181 }
182
183 return {};
184}
185
186/* See build-id.h. */
187
189build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id)
190{
191 return build_id_to_bfd_suffix (build_id_len, build_id, ".debug");
192}
193
194/* See build-id.h. */
195
197build_id_to_exec_bfd (size_t build_id_len, const bfd_byte *build_id)
198{
199 return build_id_to_bfd_suffix (build_id_len, build_id, "");
200}
201
202/* See build-id.h. */
203
204std::string
206{
207 const struct bfd_build_id *build_id;
208
209 build_id = build_id_bfd_get (objfile->obfd.get ());
210 if (build_id != NULL)
211 {
214 _("\nLooking for separate debug info (build-id) for "
215 "%s\n"), objfile_name (objfile));
216
217 gdb_bfd_ref_ptr abfd (build_id_to_debug_bfd (build_id->size,
218 build_id->data));
219 /* Prevent looping on a stripped .debug file. */
220 if (abfd != NULL
221 && filename_cmp (bfd_get_filename (abfd.get ()),
222 objfile_name (objfile)) == 0)
223 warning (_("\"%s\": separate debug info file has no debug info"),
224 bfd_get_filename (abfd.get ()));
225 else if (abfd != NULL)
226 return std::string (bfd_get_filename (abfd.get ()));
227 }
228
229 return std::string ();
230}
static gdb_bfd_ref_ptr build_id_to_debug_bfd_1(const std::string &link, size_t build_id_len, const bfd_byte *build_id)
Definition build-id.c:74
int build_id_verify(bfd *abfd, size_t check_len, const bfd_byte *check)
Definition build-id.c:49
gdb_bfd_ref_ptr build_id_to_exec_bfd(size_t build_id_len, const bfd_byte *build_id)
Definition build-id.c:197
static gdb_bfd_ref_ptr build_id_to_bfd_suffix(size_t build_id_len, const bfd_byte *build_id, const char *suffix)
Definition build-id.c:133
std::string find_separate_debug_file_by_buildid(struct objfile *objfile)
Definition build-id.c:205
gdb_bfd_ref_ptr build_id_to_debug_bfd(size_t build_id_len, const bfd_byte *build_id)
Definition build-id.c:189
const struct bfd_build_id * build_id_bfd_get(bfd *abfd)
Definition build-id.c:33
const char * gnutarget
Definition corefile.c:394
std::string debug_file_directory
Definition symfile.c:1355
std::string gdb_sysroot
Definition main.c:63
gdb_bfd_ref_ptr gdb_bfd_open(const char *name, const char *target, int fd, bool warn_if_slow)
Definition gdb_bfd.c:491
#define TARGET_SYSROOT_PREFIX
Definition gdb_bfd.h:40
gdb::ref_ptr< struct bfd, gdb_bfd_ref_policy > gdb_bfd_ref_ptr
Definition gdb_bfd.h:78
size_t size
Definition go32-nat.c:241
const char * objfile_name(const struct objfile *objfile)
Definition objfiles.c:1308
gdb_bfd_ref_ptr obfd
Definition objfiles.h:653
bool separate_debug_file_debug
Definition symfile.c:1243
void gdb_printf(struct ui_file *stream, const char *format,...)
Definition utils.c:1865
void gdb_flush(struct ui_file *stream)
Definition utils.c:1477
#define gdb_stdlog
Definition utils.h:196
static void check(BOOL ok, const char *file, int line)