diff options
Diffstat (limited to 'gdb/build-id.c')
| -rw-r--r-- | gdb/build-id.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/gdb/build-id.c b/gdb/build-id.c new file mode 100644 index 0000000..330ed18 --- /dev/null +++ b/gdb/build-id.c @@ -0,0 +1,168 @@ +/* build-id-related functions. + + Copyright (C) 1991-2013 Free Software Foundation, Inc. + + This file is part of GDB. + + This program 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; either version 3 of the License, or + (at your option) any later version. + + This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include "defs.h" +#include "bfd.h" +#include "elf-bfd.h" +#include "gdb_bfd.h" +#include "build-id.h" +#include "gdb_string.h" +#include "gdb_vecs.h" +#include "symfile.h" +#include "objfiles.h" +#include "filenames.h" + +/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */ + +static const struct elf_build_id * +build_id_bfd_get (bfd *abfd) +{ + if (!bfd_check_format (abfd, bfd_object) + || bfd_get_flavour (abfd) != bfd_target_elf_flavour + /* Although this is ELF_specific, it is safe to do in generic + code because it does not rely on any ELF-specific symbols at + link time, and if the ELF code is not available in BFD, then + ABFD will not have the ELF flavour. */ + || elf_tdata (abfd)->build_id == NULL) + return NULL; + + return elf_tdata (abfd)->build_id; +} + +/* See build-id.h. */ + +int +build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check) +{ + const struct elf_build_id *found; + int retval = 0; + + found = build_id_bfd_get (abfd); + + if (found == NULL) + warning (_("File \"%s\" has no build-id, file skipped"), + bfd_get_filename (abfd)); + else if (found->size != check_len + || memcmp (found->data, check, found->size) != 0) + warning (_("File \"%s\" has a different build-id, file skipped"), + bfd_get_filename (abfd)); + else + retval = 1; + + return retval; +} + +/* See build-id.h. */ + +bfd * +build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id) +{ + char *link, *debugdir; + VEC (char_ptr) *debugdir_vec; + struct cleanup *back_to; + int ix; + bfd *abfd = NULL; + + /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */ + link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1 + + 2 * build_id_len + (sizeof ".debug" - 1) + 1); + + /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will + cause "/.build-id/..." lookups. */ + + debugdir_vec = dirnames_to_char_ptr_vec (debug_file_directory); + back_to = make_cleanup_free_char_ptr_vec (debugdir_vec); + + for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix) + { + size_t debugdir_len = strlen (debugdir); + const gdb_byte *data = build_id; + size_t size = build_id_len; + char *s; + char *filename = NULL; + + memcpy (link, debugdir, debugdir_len); + s = &link[debugdir_len]; + s += sprintf (s, "/.build-id/"); + if (size > 0) + { + size--; + s += sprintf (s, "%02x", (unsigned) *data++); + } + if (size > 0) + *s++ = '/'; + while (size-- > 0) + s += sprintf (s, "%02x", (unsigned) *data++); + strcpy (s, ".debug"); + + /* lrealpath() is expensive even for the usually non-existent files. */ + if (access (link, F_OK) == 0) + filename = lrealpath (link); + + if (filename == NULL) + continue; + + /* We expect to be silent on the non-existing files. */ + abfd = gdb_bfd_open_maybe_remote (filename); + if (abfd == NULL) + continue; + + if (build_id_verify (abfd, build_id_len, build_id)) + break; + + gdb_bfd_unref (abfd); + abfd = NULL; + } + + do_cleanups (back_to); + return abfd; +} + +/* See build-id.h. */ + +char * +find_separate_debug_file_by_buildid (struct objfile *objfile) +{ + const struct elf_build_id *build_id; + + build_id = build_id_bfd_get (objfile->obfd); + if (build_id != NULL) + { + bfd *abfd; + + abfd = build_id_to_debug_bfd (build_id->size, build_id->data); + /* Prevent looping on a stripped .debug file. */ + if (abfd != NULL + && filename_cmp (bfd_get_filename (abfd), + objfile_name (objfile)) == 0) + { + warning (_("\"%s\": separate debug info file has no debug info"), + bfd_get_filename (abfd)); + gdb_bfd_unref (abfd); + } + else if (abfd != NULL) + { + char *result = xstrdup (bfd_get_filename (abfd)); + + gdb_bfd_unref (abfd); + return result; + } + } + return NULL; +} |