1 /* Find an ELF file for a module from its build ID.
2 Copyright (C) 2007-2010 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
5 Red Hat elfutils is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by the
7 Free Software Foundation; version 2 of the License.
9 Red Hat elfutils is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 General Public License for more details.
14 You should have received a copy of the GNU General Public License along
15 with Red Hat elfutils; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18 In addition, as a special exception, Red Hat, Inc. gives You the
19 additional right to link the code of Red Hat elfutils with code licensed
20 under any Open Source Initiative certified open source license
21 (http://www.opensource.org/licenses/index.php) which requires the
22 distribution of source code with any binary distribution and to
23 distribute linked combinations of the two. Non-GPL Code permitted under
24 this exception must only link to the code of Red Hat elfutils through
25 those well defined interfaces identified in the file named EXCEPTION
26 found in the source code files (the "Approved Interfaces"). The files
27 of Non-GPL Code may instantiate templates or use macros or inline
28 functions from the Approved Interfaces without causing the resulting
29 work to be covered by the GNU General Public License. Only Red Hat,
30 Inc. may make changes or additions to the list of Approved Interfaces.
31 Red Hat's grant of this exception is conditioned upon your not adding
32 any new exceptions. If you wish to add a new Approved Interface or
33 exception, please contact Red Hat. You must obey the GNU General Public
34 License in all respects for all of the Red Hat elfutils code and other
35 code used in conjunction with Red Hat elfutils except the Non-GPL Code
36 covered by this exception. If you modify this file, you may extend this
37 exception to your version of the file, but you are not obligated to do
38 so. If you do not wish to provide this exception without modification,
39 you must delete this exception statement from your version and license
40 this file solely under the GPL without exception.
42 Red Hat elfutils is an included package of the Open Invention Network.
43 An included package of the Open Invention Network is a package for which
44 Open Invention Network licensees cross-license their patents. No patent
45 license is granted, either expressly or impliedly, by designation as an
46 included package. Should you wish to participate in the Open Invention
47 Network licensing program, please visit www.openinventionnetwork.com
48 <http://www.openinventionnetwork.com>. */
58 __libdwfl_open_by_build_id (Dwfl_Module *mod, bool debug, char **file_name)
60 /* If *FILE_NAME was primed into the module, leave it there
61 as the fallback when we have nothing to offer. */
63 if (mod->build_id_len <= 0)
66 const size_t id_len = mod->build_id_len;
67 const uint8_t *id = mod->build_id_bits;
69 /* Search debuginfo_path directories' .build-id/ subdirectories. */
71 char id_name[sizeof "/.build-id/" + 1 + id_len * 2 + sizeof ".debug" - 1];
72 strcpy (id_name, "/.build-id/");
73 int n = snprintf (&id_name[sizeof "/.build-id/" - 1],
74 4, "%02" PRIx8 "/", (uint8_t) id[0]);
76 for (size_t i = 1; i < id_len; ++i)
78 n = snprintf (&id_name[sizeof "/.build-id/" - 1 + 3 + (i - 1) * 2],
79 3, "%02" PRIx8, (uint8_t) id[i]);
83 strcpy (&id_name[sizeof "/.build-id/" - 1 + 3 + (id_len - 1) * 2],
86 const Dwfl_Callbacks *const cb = mod->dwfl->callbacks;
87 char *path = strdupa ((cb->debuginfo_path ? *cb->debuginfo_path : NULL)
88 ?: DEFAULT_DEBUGINFO_PATH);
92 while (fd < 0 && (dir = strsep (&path, ":")) != NULL)
94 if (dir[0] == '+' || dir[0] == '-')
97 /* Only absolute directory names are useful to us. */
101 size_t dirlen = strlen (dir);
102 char *name = malloc (dirlen + sizeof id_name);
103 if (unlikely (name == NULL))
105 memcpy (mempcpy (name, dir, dirlen), id_name, sizeof id_name);
107 fd = TEMP_FAILURE_RETRY (open64 (name, O_RDONLY));
110 if (*file_name != NULL)
112 *file_name = canonicalize_file_name (name);
113 if (*file_name == NULL)
122 /* If we simply found nothing, clear errno. If we had some other error
123 with the file, report that. Possibly this should treat other errors
124 like ENOENT too. But ignoring all errors could mask some that should
126 if (fd < 0 && errno == ENOENT)
133 dwfl_build_id_find_elf (Dwfl_Module *mod,
134 void **userdata __attribute__ ((unused)),
135 const char *modname __attribute__ ((unused)),
136 Dwarf_Addr base __attribute__ ((unused)),
137 char **file_name, Elf **elfp)
140 int fd = __libdwfl_open_by_build_id (mod, false, file_name);
143 Dwfl_Error error = __libdw_open_file (&fd, elfp, true, false);
144 if (error != DWFL_E_NOERROR)
145 __libdwfl_seterrno (error);
146 else if (__libdwfl_find_build_id (mod, false, *elfp) == 2)
148 /* This is a backdoor signal to short-circuit the ID refresh. */
149 mod->main.valid = true;
154 /* This file does not contain the ID it should! */
163 else if (errno == 0 && mod->build_id_len > 0)
164 /* Setting this with no file yet loaded is a marker that
165 the build ID is authoritative even if we also know a
166 putative *FILE_NAME. */
167 mod->main.valid = true;
171 INTDEF (dwfl_build_id_find_elf)