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-rw-r--r--libdwfl/find-debuginfo.c292
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diff --git a/libdwfl/find-debuginfo.c b/libdwfl/find-debuginfo.c
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+/* Standard find_debuginfo callback for libdwfl.
+ Copyright (C) 2005-2010 Red Hat, Inc.
+ This file is part of Red Hat elfutils.
+
+ Red Hat elfutils 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; version 2 of the License.
+
+ Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
+
+ In addition, as a special exception, Red Hat, Inc. gives You the
+ additional right to link the code of Red Hat elfutils with code licensed
+ under any Open Source Initiative certified open source license
+ (http://www.opensource.org/licenses/index.php) which requires the
+ distribution of source code with any binary distribution and to
+ distribute linked combinations of the two. Non-GPL Code permitted under
+ this exception must only link to the code of Red Hat elfutils through
+ those well defined interfaces identified in the file named EXCEPTION
+ found in the source code files (the "Approved Interfaces"). The files
+ of Non-GPL Code may instantiate templates or use macros or inline
+ functions from the Approved Interfaces without causing the resulting
+ work to be covered by the GNU General Public License. Only Red Hat,
+ Inc. may make changes or additions to the list of Approved Interfaces.
+ Red Hat's grant of this exception is conditioned upon your not adding
+ any new exceptions. If you wish to add a new Approved Interface or
+ exception, please contact Red Hat. You must obey the GNU General Public
+ License in all respects for all of the Red Hat elfutils code and other
+ code used in conjunction with Red Hat elfutils except the Non-GPL Code
+ covered by this exception. If you modify this file, you may extend this
+ exception to your version of the file, but you are not obligated to do
+ so. If you do not wish to provide this exception without modification,
+ you must delete this exception statement from your version and license
+ this file solely under the GPL without exception.
+
+ Red Hat elfutils is an included package of the Open Invention Network.
+ An included package of the Open Invention Network is a package for which
+ Open Invention Network licensees cross-license their patents. No patent
+ license is granted, either expressly or impliedly, by designation as an
+ included package. Should you wish to participate in the Open Invention
+ Network licensing program, please visit www.openinventionnetwork.com
+ <http://www.openinventionnetwork.com>. */
+
+#include "libdwflP.h"
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include "system.h"
+
+
+/* Try to open64 [DIR/][SUBDIR/]DEBUGLINK, return file descriptor or -1.
+ On success, *DEBUGINFO_FILE_NAME has the malloc'd name of the open file. */
+static int
+try_open (const struct stat64 *main_stat,
+ const char *dir, const char *subdir, const char *debuglink,
+ char **debuginfo_file_name)
+{
+ char *fname;
+ if (dir == NULL && subdir == NULL)
+ {
+ fname = strdup (debuglink);
+ if (fname == NULL)
+ return -1;
+ }
+ else if ((subdir == NULL ? asprintf (&fname, "%s/%s", dir, debuglink)
+ : dir == NULL ? asprintf (&fname, "%s/%s", subdir, debuglink)
+ : asprintf (&fname, "%s/%s/%s", dir, subdir, debuglink)) < 0)
+ return -1;
+
+ struct stat64 st;
+ int fd = TEMP_FAILURE_RETRY (open64 (fname, O_RDONLY));
+ if (fd < 0)
+ free (fname);
+ else if (fstat64 (fd, &st) == 0
+ && st.st_ino == main_stat->st_ino
+ && st.st_dev == main_stat->st_dev)
+ {
+ /* This is the main file by another name. Don't look at it again. */
+ close (fd);
+ errno = ENOENT;
+ fd = -1;
+ }
+ else
+ *debuginfo_file_name = fname;
+
+ return fd;
+}
+
+/* Return true iff the FD's contents CRC matches DEBUGLINK_CRC. */
+static inline bool
+check_crc (int fd, GElf_Word debuglink_crc)
+{
+ uint32_t file_crc;
+ return (__libdwfl_crc32_file (fd, &file_crc) == 0
+ && file_crc == debuglink_crc);
+}
+
+static bool
+validate (Dwfl_Module *mod, int fd, bool check, GElf_Word debuglink_crc)
+{
+ /* If we have a build ID, check only that. */
+ if (mod->build_id_len > 0)
+ {
+ /* We need to open an Elf handle on the file so we can check its
+ build ID note for validation. Backdoor the handle into the
+ module data structure since we had to open it early anyway. */
+
+ mod->debug.valid = false;
+ Dwfl_Error error = __libdw_open_file (&fd, &mod->debug.elf, false, false);
+ if (error != DWFL_E_NOERROR)
+ __libdwfl_seterrno (error);
+ else if (likely (__libdwfl_find_build_id (mod, false,
+ mod->debug.elf) == 2))
+ /* Also backdoor the gratuitous flag. */
+ mod->debug.valid = true;
+ else
+ {
+ /* A mismatch! */
+ elf_end (mod->debug.elf);
+ mod->debug.elf = NULL;
+ close (fd);
+ fd = -1;
+ }
+
+ return mod->debug.valid;
+ }
+
+ return !check || check_crc (fd, debuglink_crc);
+}
+
+static int
+find_debuginfo_in_path (Dwfl_Module *mod, const char *file_name,
+ const char *debuglink_file, GElf_Word debuglink_crc,
+ char **debuginfo_file_name)
+{
+ bool cancheck = debuglink_crc != (GElf_Word) 0;
+
+ const char *file_basename = file_name == NULL ? NULL : basename (file_name);
+ if (debuglink_file == NULL)
+ {
+ if (file_basename == NULL)
+ {
+ errno = 0;
+ return -1;
+ }
+
+ size_t len = strlen (file_basename);
+ char *localname = alloca (len + sizeof ".debug");
+ memcpy (localname, file_basename, len);
+ memcpy (&localname[len], ".debug", sizeof ".debug");
+ debuglink_file = localname;
+ cancheck = false;
+ }
+
+ /* Look for a file named DEBUGLINK_FILE in the directories
+ indicated by the debug directory path setting. */
+
+ const Dwfl_Callbacks *const cb = mod->dwfl->callbacks;
+ char *path = strdupa ((cb->debuginfo_path ? *cb->debuginfo_path : NULL)
+ ?: DEFAULT_DEBUGINFO_PATH);
+
+ /* A leading - or + in the whole path sets whether to check file CRCs. */
+ bool defcheck = true;
+ if (path[0] == '-' || path[0] == '+')
+ {
+ defcheck = path[0] == '+';
+ ++path;
+ }
+
+ /* XXX dev/ino should be cached in struct dwfl_file. */
+ struct stat64 main_stat;
+ if (unlikely ((mod->main.fd != -1 ? fstat64 (mod->main.fd, &main_stat)
+ : file_name != NULL ? stat64 (file_name, &main_stat)
+ : -1) < 0))
+ {
+ main_stat.st_dev = 0;
+ main_stat.st_ino = 0;
+ }
+
+ char *file_dirname = (file_basename == file_name ? NULL
+ : strndupa (file_name, file_basename - 1 - file_name));
+ char *p;
+ while ((p = strsep (&path, ":")) != NULL)
+ {
+ /* A leading - or + says whether to check file CRCs for this element. */
+ bool check = defcheck;
+ if (*p == '+' || *p == '-')
+ check = *p++ == '+';
+ check = check && cancheck;
+
+ const char *dir, *subdir;
+ switch (p[0])
+ {
+ case '\0':
+ /* An empty entry says to try the main file's directory. */
+ dir = file_dirname;
+ subdir = NULL;
+ break;
+ case '/':
+ /* An absolute path says to look there for a subdirectory
+ named by the main file's absolute directory.
+ This cannot be applied to a relative file name. */
+ if (file_dirname == NULL || file_dirname[0] != '/')
+ continue;
+ dir = p;
+ subdir = file_dirname + 1;
+ break;
+ default:
+ /* A relative path says to try a subdirectory of that name
+ in the main file's directory. */
+ dir = file_dirname;
+ subdir = p;
+ break;
+ }
+
+ char *fname = NULL;
+ int fd = try_open (&main_stat, dir, subdir, debuglink_file, &fname);
+ if (fd < 0)
+ switch (errno)
+ {
+ case ENOENT:
+ case ENOTDIR:
+ continue;
+ default:
+ return -1;
+ }
+ if (validate (mod, fd, check, debuglink_crc))
+ {
+ *debuginfo_file_name = fname;
+ return fd;
+ }
+ free (fname);
+ close (fd);
+ }
+
+ /* No dice. */
+ errno = 0;
+ return -1;
+}
+
+int
+dwfl_standard_find_debuginfo (Dwfl_Module *mod,
+ void **userdata __attribute__ ((unused)),
+ const char *modname __attribute__ ((unused)),
+ GElf_Addr base __attribute__ ((unused)),
+ const char *file_name,
+ const char *debuglink_file,
+ GElf_Word debuglink_crc,
+ char **debuginfo_file_name)
+{
+ /* First try by build ID if we have one. If that succeeds or fails
+ other than just by finding nothing, that's all we do. */
+ const unsigned char *bits;
+ GElf_Addr vaddr;
+ if (INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr) > 0)
+ {
+ int fd = INTUSE(dwfl_build_id_find_debuginfo) (mod,
+ NULL, NULL, 0,
+ NULL, NULL, 0,
+ debuginfo_file_name);
+ if (fd >= 0 || mod->debug.elf != NULL || errno != 0)
+ return fd;
+ }
+
+ /* Failing that, search the path by name. */
+ int fd = find_debuginfo_in_path (mod, file_name,
+ debuglink_file, debuglink_crc,
+ debuginfo_file_name);
+
+ if (fd < 0 && errno == 0)
+ {
+ /* If FILE_NAME is a symlink, the debug file might be associated
+ with the symlink target name instead. */
+
+ char *canon = canonicalize_file_name (file_name);
+ if (canon != NULL && strcmp (file_name, canon))
+ fd = find_debuginfo_in_path (mod, canon,
+ debuglink_file, debuglink_crc,
+ debuginfo_file_name);
+ free (canon);
+ }
+
+ return fd;
+}
+INTDEF (dwfl_standard_find_debuginfo)