1 /* Return build ID information for a module. 2 Copyright (C) 2007-2010 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 5 Red Hat elfutils is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by the 7 Free Software Foundation; version 2 of the License. 8 9 Red Hat elfutils is distributed in the hope that it will be useful, but 10 WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 General Public License for more details. 13 14 You should have received a copy of the GNU General Public License along 15 with Red Hat elfutils; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 17 18 In addition, as a special exception, Red Hat, Inc. gives You the 19 additional right to link the code of Red Hat elfutils with code licensed 20 under any Open Source Initiative certified open source license 21 (http://www.opensource.org/licenses/index.php) which requires the 22 distribution of source code with any binary distribution and to 23 distribute linked combinations of the two. Non-GPL Code permitted under 24 this exception must only link to the code of Red Hat elfutils through 25 those well defined interfaces identified in the file named EXCEPTION 26 found in the source code files (the "Approved Interfaces"). The files 27 of Non-GPL Code may instantiate templates or use macros or inline 28 functions from the Approved Interfaces without causing the resulting 29 work to be covered by the GNU General Public License. Only Red Hat, 30 Inc. may make changes or additions to the list of Approved Interfaces. 31 Red Hat's grant of this exception is conditioned upon your not adding 32 any new exceptions. If you wish to add a new Approved Interface or 33 exception, please contact Red Hat. You must obey the GNU General Public 34 License in all respects for all of the Red Hat elfutils code and other 35 code used in conjunction with Red Hat elfutils except the Non-GPL Code 36 covered by this exception. If you modify this file, you may extend this 37 exception to your version of the file, but you are not obligated to do 38 so. If you do not wish to provide this exception without modification, 39 you must delete this exception statement from your version and license 40 this file solely under the GPL without exception. 41 42 Red Hat elfutils is an included package of the Open Invention Network. 43 An included package of the Open Invention Network is a package for which 44 Open Invention Network licensees cross-license their patents. No patent 45 license is granted, either expressly or impliedly, by designation as an 46 included package. Should you wish to participate in the Open Invention 47 Network licensing program, please visit www.openinventionnetwork.com 48 <http://www.openinventionnetwork.com>. */ 49 50 #include "libdwflP.h" 51 52 static int 53 found_build_id (Dwfl_Module *mod, bool set, 54 const void *bits, int len, GElf_Addr vaddr) 55 { 56 if (!set) 57 /* When checking bits, we do not compare VADDR because the 58 address found in a debuginfo file may not match the main 59 file as modified by prelink. */ 60 return 1 + (mod->build_id_len == len 61 && !memcmp (bits, mod->build_id_bits, len)); 62 63 void *copy = malloc (len); 64 if (unlikely (copy == NULL)) 65 { 66 __libdwfl_seterrno (DWFL_E_NOMEM); 67 return -1; 68 } 69 70 mod->build_id_bits = memcpy (copy, bits, len); 71 mod->build_id_vaddr = vaddr; 72 mod->build_id_len = len; 73 return len; 74 } 75 76 #define NO_VADDR ((GElf_Addr) -1l) 77 78 static int 79 check_notes (Dwfl_Module *mod, bool set, Elf_Data *data, GElf_Addr data_vaddr) 80 { 81 size_t pos = 0; 82 GElf_Nhdr nhdr; 83 size_t name_pos; 84 size_t desc_pos; 85 while ((pos = gelf_getnote (data, pos, &nhdr, &name_pos, &desc_pos)) > 0) 86 if (nhdr.n_type == NT_GNU_BUILD_ID 87 && nhdr.n_namesz == sizeof "GNU" && !memcmp (data->d_buf + name_pos, 88 "GNU", sizeof "GNU")) 89 return found_build_id (mod, set, 90 data->d_buf + desc_pos, nhdr.n_descsz, 91 data_vaddr == NO_VADDR ? 0 92 : data_vaddr + desc_pos); 93 return 0; 94 } 95 96 int 97 internal_function 98 __libdwfl_find_build_id (Dwfl_Module *mod, bool set, Elf *elf) 99 { 100 size_t shstrndx = SHN_UNDEF; 101 int result = 0; 102 103 Elf_Scn *scn = elf_nextscn (elf, NULL); 104 105 if (scn == NULL) 106 { 107 /* No sections, have to look for phdrs. */ 108 GElf_Ehdr ehdr_mem; 109 GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem); 110 size_t phnum; 111 if (unlikely (ehdr == NULL) 112 || unlikely (elf_getphdrnum (elf, &phnum) != 0)) 113 { 114 __libdwfl_seterrno (DWFL_E_LIBELF); 115 return -1; 116 } 117 for (size_t i = 0; result == 0 && i < phnum; ++i) 118 { 119 GElf_Phdr phdr_mem; 120 GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem); 121 if (likely (phdr != NULL) && phdr->p_type == PT_NOTE) 122 result = check_notes (mod, set, 123 elf_getdata_rawchunk (elf, 124 phdr->p_offset, 125 phdr->p_filesz, 126 ELF_T_NHDR), 127 dwfl_adjusted_address (mod, phdr->p_vaddr)); 128 } 129 } 130 else 131 do 132 { 133 GElf_Shdr shdr_mem; 134 GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); 135 if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE) 136 { 137 /* Determine the right sh_addr in this module. */ 138 GElf_Addr vaddr = 0; 139 if (!(shdr->sh_flags & SHF_ALLOC)) 140 vaddr = NO_VADDR; 141 else if (mod->e_type != ET_REL) 142 vaddr = dwfl_adjusted_address (mod, shdr->sh_addr); 143 else if (__libdwfl_relocate_value (mod, elf, &shstrndx, 144 elf_ndxscn (scn), &vaddr)) 145 vaddr = NO_VADDR; 146 result = check_notes (mod, set, elf_getdata (scn, NULL), vaddr); 147 } 148 } 149 while (result == 0 && (scn = elf_nextscn (elf, scn)) != NULL); 150 151 return result; 152 } 153 154 int 155 dwfl_module_build_id (Dwfl_Module *mod, 156 const unsigned char **bits, GElf_Addr *vaddr) 157 { 158 if (mod == NULL) 159 return -1; 160 161 if (mod->build_id_len == 0 && mod->main.elf != NULL) 162 { 163 /* We have the file, but have not examined it yet. */ 164 int result = __libdwfl_find_build_id (mod, true, mod->main.elf); 165 if (result <= 0) 166 { 167 mod->build_id_len = -1; /* Cache negative result. */ 168 return result; 169 } 170 } 171 172 if (mod->build_id_len <= 0) 173 return 0; 174 175 *bits = mod->build_id_bits; 176 *vaddr = mod->build_id_vaddr; 177 return mod->build_id_len; 178 } 179 INTDEF (dwfl_module_build_id) 180 NEW_VERSION (dwfl_module_build_id, ELFUTILS_0.138) 181 182 #ifdef SHARED 183 COMPAT_VERSION (dwfl_module_build_id, ELFUTILS_0.130, vaddr_at_end) 184 185 int 186 _compat_vaddr_at_end_dwfl_module_build_id (Dwfl_Module *mod, 187 const unsigned char **bits, 188 GElf_Addr *vaddr) 189 { 190 int result = INTUSE(dwfl_module_build_id) (mod, bits, vaddr); 191 if (result > 0) 192 *vaddr += (result + 3) & -4; 193 return result; 194 } 195 #endif 196
