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- /* build-id-related functions.
- Copyright (C) 1991-2022 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 "gdb_bfd.h"
- #include "build-id.h"
- #include "gdbsupport/gdb_vecs.h"
- #include "symfile.h"
- #include "objfiles.h"
- #include "filenames.h"
- #include "gdbcore.h"
- /* See build-id.h. */
- const struct bfd_build_id *
- build_id_bfd_get (bfd *abfd)
- {
- if (!bfd_check_format (abfd, bfd_object)
- && !bfd_check_format (abfd, bfd_core))
- return NULL;
- if (abfd->build_id != NULL)
- return abfd->build_id;
- /* No build-id */
- return NULL;
- }
- /* See build-id.h. */
- int
- build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check)
- {
- const struct bfd_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;
- }
- /* Helper for build_id_to_debug_bfd. LINK is a path to a potential
- build-id-based separate debug file, potentially a symlink to the real file.
- If the file exists and matches BUILD_ID, return a BFD reference to it. */
- static gdb_bfd_ref_ptr
- build_id_to_debug_bfd_1 (const std::string &link, size_t build_id_len,
- const bfd_byte *build_id)
- {
- if (separate_debug_file_debug)
- {
- gdb_printf (gdb_stdlog, _(" Trying %s..."), link.c_str ());
- gdb_flush (gdb_stdlog);
- }
- /* lrealpath() is expensive even for the usually non-existent files. */
- gdb::unique_xmalloc_ptr<char> filename_holder;
- const char *filename = nullptr;
- if (startswith (link, TARGET_SYSROOT_PREFIX))
- filename = link.c_str ();
- else if (access (link.c_str (), F_OK) == 0)
- {
- filename_holder.reset (lrealpath (link.c_str ()));
- filename = filename_holder.get ();
- }
- if (filename == NULL)
- {
- if (separate_debug_file_debug)
- gdb_printf (gdb_stdlog,
- _(" no, unable to compute real path\n"));
- return {};
- }
- /* We expect to be silent on the non-existing files. */
- gdb_bfd_ref_ptr debug_bfd = gdb_bfd_open (filename, gnutarget);
- if (debug_bfd == NULL)
- {
- if (separate_debug_file_debug)
- gdb_printf (gdb_stdlog, _(" no, unable to open.\n"));
- return {};
- }
- if (!build_id_verify (debug_bfd.get(), build_id_len, build_id))
- {
- if (separate_debug_file_debug)
- gdb_printf (gdb_stdlog, _(" no, build-id does not match.\n"));
- return {};
- }
- if (separate_debug_file_debug)
- gdb_printf (gdb_stdlog, _(" yes!\n"));
- return debug_bfd;
- }
- /* Common code for finding BFDs of a given build-id. This function
- works with both debuginfo files (SUFFIX == ".debug") and executable
- files (SUFFIX == ""). */
- static gdb_bfd_ref_ptr
- build_id_to_bfd_suffix (size_t build_id_len, const bfd_byte *build_id,
- const char *suffix)
- {
- /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will
- cause "/.build-id/..." lookups. */
- std::vector<gdb::unique_xmalloc_ptr<char>> debugdir_vec
- = dirnames_to_char_ptr_vec (debug_file_directory.c_str ());
- for (const gdb::unique_xmalloc_ptr<char> &debugdir : debugdir_vec)
- {
- const gdb_byte *data = build_id;
- size_t size = build_id_len;
- /* Compute where the file named after the build-id would be.
- If debugdir is "/usr/lib/debug" and the build-id is abcdef, this will
- give "/usr/lib/debug/.build-id/ab/cdef.debug". */
- std::string link = debugdir.get ();
- link += "/.build-id/";
- if (size > 0)
- {
- size--;
- string_appendf (link, "%02x/", (unsigned) *data++);
- }
- while (size-- > 0)
- string_appendf (link, "%02x", (unsigned) *data++);
- link += suffix;
- gdb_bfd_ref_ptr debug_bfd
- = build_id_to_debug_bfd_1 (link, build_id_len, build_id);
- if (debug_bfd != NULL)
- return debug_bfd;
- /* Try to look under the sysroot as well. If the sysroot is
- "/the/sysroot", it will give
- "/the/sysroot/usr/lib/debug/.build-id/ab/cdef.debug". */
- if (!gdb_sysroot.empty ())
- {
- link = gdb_sysroot + link;
- debug_bfd = build_id_to_debug_bfd_1 (link, build_id_len, build_id);
- if (debug_bfd != NULL)
- return debug_bfd;
- }
- }
- return {};
- }
- /* See build-id.h. */
- gdb_bfd_ref_ptr
- build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id)
- {
- return build_id_to_bfd_suffix (build_id_len, build_id, ".debug");
- }
- /* See build-id.h. */
- gdb_bfd_ref_ptr
- build_id_to_exec_bfd (size_t build_id_len, const bfd_byte *build_id)
- {
- return build_id_to_bfd_suffix (build_id_len, build_id, "");
- }
- /* See build-id.h. */
- std::string
- find_separate_debug_file_by_buildid (struct objfile *objfile)
- {
- const struct bfd_build_id *build_id;
- build_id = build_id_bfd_get (objfile->obfd);
- if (build_id != NULL)
- {
- if (separate_debug_file_debug)
- gdb_printf (gdb_stdlog,
- _("\nLooking for separate debug info (build-id) for "
- "%s\n"), objfile_name (objfile));
- gdb_bfd_ref_ptr 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.get ()),
- objfile_name (objfile)) == 0)
- warning (_("\"%s\": separate debug info file has no debug info"),
- bfd_get_filename (abfd.get ()));
- else if (abfd != NULL)
- return std::string (bfd_get_filename (abfd.get ()));
- }
- return std::string ();
- }
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