Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libdwfl/find-debuginfo.c b/libdwfl/find-debuginfo.c
new file mode 100644
index 0000000..6d5a42a
--- /dev/null
+++ b/libdwfl/find-debuginfo.c
@@ -0,0 +1,402 @@
+/* Standard find_debuginfo callback for libdwfl.
+ Copyright (C) 2005-2010, 2014, 2015 Red Hat, Inc.
+ This file is part of elfutils.
+
+ This file is free software; you can redistribute it and/or modify
+ it under the terms of either
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at
+ your option) any later version
+
+ or
+
+ * the GNU General Public License as published by the Free
+ Software Foundation; either version 2 of the License, or (at
+ your option) any later version
+
+ or both in parallel, as here.
+
+ 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 copies of the GNU General Public License and
+ the GNU Lesser General Public License along with this program. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libdwflP.h"
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include "system.h"
+
+
+/* Try to open [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 stat *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 (unlikely (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 stat st;
+ int fd = TEMP_FAILURE_RETRY (open (fname, O_RDONLY));
+ if (fd < 0)
+ free (fname);
+ else if (fstat (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. */
+ free (fname);
+ 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)
+{
+ /* For alt debug files always check the build-id from the Dwarf and alt. */
+ if (mod->dw != NULL)
+ {
+ bool valid = false;
+ const void *build_id;
+ const char *altname;
+ ssize_t build_id_len = INTUSE(dwelf_dwarf_gnu_debugaltlink) (mod->dw,
+ &altname,
+ &build_id);
+ if (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. */
+ Dwfl_Error error = __libdw_open_file (&fd, &mod->alt_elf,
+ false, false);
+ if (error != DWFL_E_NOERROR)
+ __libdwfl_seterrno (error);
+ else
+ {
+ const void *alt_build_id;
+ ssize_t alt_len = INTUSE(dwelf_elf_gnu_build_id) (mod->alt_elf,
+ &alt_build_id);
+ if (alt_len > 0 && alt_len == build_id_len
+ && memcmp (build_id, alt_build_id, alt_len) == 0)
+ valid = true;
+ else
+ {
+ /* A mismatch! */
+ elf_end (mod->alt_elf);
+ mod->alt_elf = NULL;
+ close (fd);
+ fd = -1;
+ }
+ }
+ }
+ return valid;
+ }
+
+ /* 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);
+ char *localname = NULL;
+
+ /* We invent a debuglink .debug name if NULL, but then want to try the
+ basename too. */
+ bool debuglink_null = debuglink_file == NULL;
+ if (debuglink_null)
+ {
+ /* For a alt debug multi file we need a name, for a separate debug
+ name we may be able to fall back on file_basename.debug. */
+ if (file_basename == NULL || mod->dw != NULL)
+ {
+ errno = 0;
+ return -1;
+ }
+
+ size_t len = strlen (file_basename);
+ localname = malloc (len + sizeof ".debug");
+ if (unlikely (localname == NULL))
+ return -1;
+ 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 *localpath = strdup ((cb->debuginfo_path ? *cb->debuginfo_path : NULL)
+ ?: DEFAULT_DEBUGINFO_PATH);
+ if (unlikely (localpath == NULL))
+ {
+ free (localname);
+ return -1;
+ }
+
+ /* A leading - or + in the whole path sets whether to check file CRCs. */
+ bool defcheck = true;
+ char *path = localpath;
+ if (path[0] == '-' || path[0] == '+')
+ {
+ defcheck = path[0] == '+';
+ ++path;
+ }
+
+ /* XXX dev/ino should be cached in struct dwfl_file. */
+ struct stat main_stat;
+ if (unlikely ((mod->main.fd != -1 ? fstat (mod->main.fd, &main_stat)
+ : file_name != NULL ? stat (file_name, &main_stat)
+ : -1) < 0))
+ {
+ main_stat.st_dev = 0;
+ main_stat.st_ino = 0;
+ }
+
+ char *file_dirname = (file_basename == file_name ? NULL
+ : strndup (file_name, file_basename - 1 - file_name));
+ if (file_basename != file_name && file_dirname == NULL)
+ {
+ free (localpath);
+ free (localname);
+ return -1;
+ }
+ 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;
+
+ /* Try the basename too, if we made up the debuglink name and this
+ is not the main directory. */
+ bool try_file_basename;
+
+ const char *dir, *subdir, *file;
+ switch (p[0])
+ {
+ case '\0':
+ /* An empty entry says to try the main file's directory. */
+ dir = file_dirname;
+ subdir = NULL;
+ file = debuglink_file;
+ try_file_basename = false;
+ 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. For alt debug files
+ it means to look for the basename file in that dir or the
+ .dwz subdir (see below). */
+ if (mod->dw == NULL
+ && (file_dirname == NULL || file_dirname[0] != '/'))
+ continue;
+ dir = p;
+ if (mod->dw == NULL)
+ {
+ subdir = file_dirname;
+ /* We want to explore all sub-subdirs. Chop off one slash
+ at a time. */
+ explore_dir:
+ subdir = strchr (subdir, '/');
+ if (subdir != NULL)
+ subdir = subdir + 1;
+ if (subdir && *subdir == 0)
+ continue;
+ file = debuglink_file;
+ }
+ else
+ {
+ subdir = NULL;
+ file = basename (debuglink_file);
+ }
+ try_file_basename = debuglink_null;
+ break;
+ default:
+ /* A relative path says to try a subdirectory of that name
+ in the main file's directory. */
+ dir = file_dirname;
+ subdir = p;
+ file = debuglink_file;
+ try_file_basename = debuglink_null;
+ break;
+ }
+
+ char *fname = NULL;
+ int fd = try_open (&main_stat, dir, subdir, file, &fname);
+ if (fd < 0 && try_file_basename)
+ fd = try_open (&main_stat, dir, subdir, file_basename, &fname);
+ if (fd < 0)
+ switch (errno)
+ {
+ case ENOENT:
+ case ENOTDIR:
+ /* If we are looking for the alt file also try the .dwz subdir.
+ But only if this is the empty or absolute path. */
+ if (mod->dw != NULL && (p[0] == '\0' || p[0] == '/'))
+ {
+ fd = try_open (&main_stat, dir, ".dwz",
+ basename (file), &fname);
+ if (fd < 0)
+ {
+ if (errno != ENOENT && errno != ENOTDIR)
+ goto fail_free;
+ else
+ continue;
+ }
+ break;
+ }
+ /* If possible try again with a sub-subdir. */
+ if (mod->dw == NULL && subdir)
+ goto explore_dir;
+ continue;
+ default:
+ goto fail_free;
+ }
+ if (validate (mod, fd, check, debuglink_crc))
+ {
+ free (localpath);
+ free (localname);
+ free (file_dirname);
+ *debuginfo_file_name = fname;
+ return fd;
+ }
+ free (fname);
+ close (fd);
+ }
+
+ /* No dice. */
+ errno = 0;
+fail_free:
+ free (localpath);
+ free (localname);
+ free (file_dirname);
+ 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)
+ {
+ /* Dropping most arguments means we cannot rely on them in
+ dwfl_build_id_find_debuginfo. But leave it that way since
+ some user code out there also does this, so we'll have to
+ handle it anyway. */
+ int fd = INTUSE(dwfl_build_id_find_debuginfo) (mod,
+ NULL, NULL, 0,
+ NULL, NULL, 0,
+ debuginfo_file_name);
+
+ /* Did the build_id callback find something or report an error?
+ Then we are done. Otherwise fallback on path based search. */
+ if (fd >= 0
+ || (mod->dw == NULL && mod->debug.elf != NULL)
+ || (mod->dw != NULL && mod->alt_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 && file_name != NULL)
+ {
+ /* 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)