1 /* Standard find_debuginfo callback for libdwfl.
2 Copyright (C) 2005-2010 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 /* Try to open64 [DIR/][SUBDIR/]DEBUGLINK, return file descriptor or -1.
59 On success, *DEBUGINFO_FILE_NAME has the malloc'd name of the open file. */
61 try_open (const struct stat64 *main_stat,
62 const char *dir, const char *subdir, const char *debuglink,
63 char **debuginfo_file_name)
66 if (dir == NULL && subdir == NULL)
68 fname = strdup (debuglink);
72 else if ((subdir == NULL ? asprintf (&fname, "%s/%s", dir, debuglink)
73 : dir == NULL ? asprintf (&fname, "%s/%s", subdir, debuglink)
74 : asprintf (&fname, "%s/%s/%s", dir, subdir, debuglink)) < 0)
78 int fd = TEMP_FAILURE_RETRY (open64 (fname, O_RDONLY));
81 else if (fstat64 (fd, &st) == 0
82 && st.st_ino == main_stat->st_ino
83 && st.st_dev == main_stat->st_dev)
85 /* This is the main file by another name. Don't look at it again. */
91 *debuginfo_file_name = fname;
96 /* Return true iff the FD's contents CRC matches DEBUGLINK_CRC. */
98 check_crc (int fd, GElf_Word debuglink_crc)
101 return (__libdwfl_crc32_file (fd, &file_crc) == 0
102 && file_crc == debuglink_crc);
106 validate (Dwfl_Module *mod, int fd, bool check, GElf_Word debuglink_crc)
108 /* If we have a build ID, check only that. */
109 if (mod->build_id_len > 0)
111 /* We need to open an Elf handle on the file so we can check its
112 build ID note for validation. Backdoor the handle into the
113 module data structure since we had to open it early anyway. */
115 mod->debug.valid = false;
116 Dwfl_Error error = __libdw_open_file (&fd, &mod->debug.elf, false, false);
117 if (error != DWFL_E_NOERROR)
118 __libdwfl_seterrno (error);
119 else if (likely (__libdwfl_find_build_id (mod, false,
120 mod->debug.elf) == 2))
121 /* Also backdoor the gratuitous flag. */
122 mod->debug.valid = true;
126 elf_end (mod->debug.elf);
127 mod->debug.elf = NULL;
132 return mod->debug.valid;
135 return !check || check_crc (fd, debuglink_crc);
139 find_debuginfo_in_path (Dwfl_Module *mod, const char *file_name,
140 const char *debuglink_file, GElf_Word debuglink_crc,
141 char **debuginfo_file_name)
143 bool cancheck = debuglink_crc != (GElf_Word) 0;
145 const char *file_basename = file_name == NULL ? NULL : basename (file_name);
146 if (debuglink_file == NULL)
148 if (file_basename == NULL)
154 size_t len = strlen (file_basename);
155 char *localname = alloca (len + sizeof ".debug");
156 memcpy (localname, file_basename, len);
157 memcpy (&localname[len], ".debug", sizeof ".debug");
158 debuglink_file = localname;
162 /* Look for a file named DEBUGLINK_FILE in the directories
163 indicated by the debug directory path setting. */
165 const Dwfl_Callbacks *const cb = mod->dwfl->callbacks;
166 char *path = strdupa ((cb->debuginfo_path ? *cb->debuginfo_path : NULL)
167 ?: DEFAULT_DEBUGINFO_PATH);
169 /* A leading - or + in the whole path sets whether to check file CRCs. */
170 bool defcheck = true;
171 if (path[0] == '-' || path[0] == '+')
173 defcheck = path[0] == '+';
177 /* XXX dev/ino should be cached in struct dwfl_file. */
178 struct stat64 main_stat;
179 if (unlikely ((mod->main.fd != -1 ? fstat64 (mod->main.fd, &main_stat)
180 : file_name != NULL ? stat64 (file_name, &main_stat)
183 main_stat.st_dev = 0;
184 main_stat.st_ino = 0;
187 char *file_dirname = (file_basename == file_name ? NULL
188 : strndupa (file_name, file_basename - 1 - file_name));
190 while ((p = strsep (&path, ":")) != NULL)
192 /* A leading - or + says whether to check file CRCs for this element. */
193 bool check = defcheck;
194 if (*p == '+' || *p == '-')
196 check = check && cancheck;
198 const char *dir, *subdir;
202 /* An empty entry says to try the main file's directory. */
207 /* An absolute path says to look there for a subdirectory
208 named by the main file's absolute directory.
209 This cannot be applied to a relative file name. */
210 if (file_dirname == NULL || file_dirname[0] != '/')
213 subdir = file_dirname + 1;
216 /* A relative path says to try a subdirectory of that name
217 in the main file's directory. */
224 int fd = try_open (&main_stat, dir, subdir, debuglink_file, &fname);
234 if (validate (mod, fd, check, debuglink_crc))
236 *debuginfo_file_name = fname;
249 dwfl_standard_find_debuginfo (Dwfl_Module *mod,
250 void **userdata __attribute__ ((unused)),
251 const char *modname __attribute__ ((unused)),
252 GElf_Addr base __attribute__ ((unused)),
253 const char *file_name,
254 const char *debuglink_file,
255 GElf_Word debuglink_crc,
256 char **debuginfo_file_name)
258 /* First try by build ID if we have one. If that succeeds or fails
259 other than just by finding nothing, that's all we do. */
260 const unsigned char *bits;
262 if (INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr) > 0)
264 int fd = INTUSE(dwfl_build_id_find_debuginfo) (mod,
267 debuginfo_file_name);
268 if (fd >= 0 || mod->debug.elf != NULL || errno != 0)
272 /* Failing that, search the path by name. */
273 int fd = find_debuginfo_in_path (mod, file_name,
274 debuglink_file, debuglink_crc,
275 debuginfo_file_name);
277 if (fd < 0 && errno == 0)
279 /* If FILE_NAME is a symlink, the debug file might be associated
280 with the symlink target name instead. */
282 char *canon = canonicalize_file_name (file_name);
283 if (canon != NULL && strcmp (file_name, canon))
284 fd = find_debuginfo_in_path (mod, canon,
285 debuglink_file, debuglink_crc,
286 debuginfo_file_name);
292 INTDEF (dwfl_standard_find_debuginfo)