1 /* build-id-related functions. 2 3 Copyright (C) 1991-2015 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #include "defs.h" 21 #include "bfd.h" 22 #include "elf-bfd.h" 23 #include "gdb_bfd.h" 24 #include "build-id.h" 25 #include "gdb_vecs.h" 26 #include "symfile.h" 27 #include "objfiles.h" 28 #include "filenames.h" 29 30 /* See build-id.h. */ 31 32 const struct elf_build_id * 33 build_id_bfd_get (bfd *abfd) 34 { 35 if (!bfd_check_format (abfd, bfd_object) 36 || bfd_get_flavour (abfd) != bfd_target_elf_flavour 37 /* Although this is ELF_specific, it is safe to do in generic 38 code because it does not rely on any ELF-specific symbols at 39 link time, and if the ELF code is not available in BFD, then 40 ABFD will not have the ELF flavour. */ 41 || elf_tdata (abfd)->build_id == NULL) 42 return NULL; 43 44 return elf_tdata (abfd)->build_id; 45 } 46 47 /* See build-id.h. */ 48 49 int 50 build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check) 51 { 52 const struct elf_build_id *found; 53 int retval = 0; 54 55 found = build_id_bfd_get (abfd); 56 57 if (found == NULL) 58 warning (_("File \"%s\" has no build-id, file skipped"), 59 bfd_get_filename (abfd)); 60 else if (found->size != check_len 61 || memcmp (found->data, check, found->size) != 0) 62 warning (_("File \"%s\" has a different build-id, file skipped"), 63 bfd_get_filename (abfd)); 64 else 65 retval = 1; 66 67 return retval; 68 } 69 70 /* See build-id.h. */ 71 72 bfd * 73 build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id) 74 { 75 char *link, *debugdir; 76 VEC (char_ptr) *debugdir_vec; 77 struct cleanup *back_to; 78 int ix; 79 bfd *abfd = NULL; 80 81 /* DEBUG_FILE_DIRECTORY/.build-id/ab/cdef */ 82 link = alloca (strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1 83 + 2 * build_id_len + (sizeof ".debug" - 1) + 1); 84 85 /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will 86 cause "/.build-id/..." lookups. */ 87 88 debugdir_vec = dirnames_to_char_ptr_vec (debug_file_directory); 89 back_to = make_cleanup_free_char_ptr_vec (debugdir_vec); 90 91 for (ix = 0; VEC_iterate (char_ptr, debugdir_vec, ix, debugdir); ++ix) 92 { 93 size_t debugdir_len = strlen (debugdir); 94 const gdb_byte *data = build_id; 95 size_t size = build_id_len; 96 char *s; 97 char *filename = NULL; 98 99 memcpy (link, debugdir, debugdir_len); 100 s = &link[debugdir_len]; 101 s += sprintf (s, "/.build-id/"); 102 if (size > 0) 103 { 104 size--; 105 s += sprintf (s, "%02x", (unsigned) *data++); 106 } 107 if (size > 0) 108 *s++ = '/'; 109 while (size-- > 0) 110 s += sprintf (s, "%02x", (unsigned) *data++); 111 strcpy (s, ".debug"); 112 113 /* lrealpath() is expensive even for the usually non-existent files. */ 114 if (access (link, F_OK) == 0) 115 filename = lrealpath (link); 116 117 if (filename == NULL) 118 continue; 119 120 /* We expect to be silent on the non-existing files. */ 121 abfd = gdb_bfd_open_maybe_remote (filename); 122 if (abfd == NULL) 123 continue; 124 125 if (build_id_verify (abfd, build_id_len, build_id)) 126 break; 127 128 gdb_bfd_unref (abfd); 129 abfd = NULL; 130 } 131 132 do_cleanups (back_to); 133 return abfd; 134 } 135 136 /* See build-id.h. */ 137 138 char * 139 find_separate_debug_file_by_buildid (struct objfile *objfile) 140 { 141 const struct elf_build_id *build_id; 142 143 build_id = build_id_bfd_get (objfile->obfd); 144 if (build_id != NULL) 145 { 146 bfd *abfd; 147 148 abfd = build_id_to_debug_bfd (build_id->size, build_id->data); 149 /* Prevent looping on a stripped .debug file. */ 150 if (abfd != NULL 151 && filename_cmp (bfd_get_filename (abfd), 152 objfile_name (objfile)) == 0) 153 { 154 warning (_("\"%s\": separate debug info file has no debug info"), 155 bfd_get_filename (abfd)); 156 gdb_bfd_unref (abfd); 157 } 158 else if (abfd != NULL) 159 { 160 char *result = xstrdup (bfd_get_filename (abfd)); 161 162 gdb_bfd_unref (abfd); 163 return result; 164 } 165 } 166 return NULL; 167 } 168