| /* Returns the build id if found in a NT_GNU_BUILD_ID note. |
| Copyright (C) 2014 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 "libdwelfP.h" |
| #include "libdwflP.h" |
| |
| #define NO_VADDR ((GElf_Addr) -1l) |
| |
| static int |
| check_notes (Elf_Data *data, GElf_Addr data_elfaddr, |
| const void **build_id_bits, GElf_Addr *build_id_elfaddr, |
| int *build_id_len) |
| { |
| size_t pos = 0; |
| GElf_Nhdr nhdr; |
| size_t name_pos; |
| size_t desc_pos; |
| while ((pos = gelf_getnote (data, pos, &nhdr, &name_pos, &desc_pos)) > 0) |
| if (nhdr.n_type == NT_GNU_BUILD_ID |
| && nhdr.n_namesz == sizeof "GNU" |
| && !memcmp (data->d_buf + name_pos, "GNU", sizeof "GNU")) |
| { |
| *build_id_bits = data->d_buf + desc_pos; |
| *build_id_elfaddr = (data_elfaddr == NO_VADDR |
| ? 0 : data_elfaddr + desc_pos); |
| *build_id_len = nhdr.n_descsz; |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* Defined here for reuse. The dwelf interface doesn't care about the |
| address of the note, but libdwfl does. */ |
| static int |
| find_elf_build_id (Dwfl_Module *mod, int e_type, Elf *elf, |
| const void **build_id_bits, GElf_Addr *build_id_elfaddr, |
| int *build_id_len) |
| { |
| size_t shstrndx = SHN_UNDEF; |
| int result = 0; |
| |
| Elf_Scn *scn = elf_nextscn (elf, NULL); |
| |
| if (scn == NULL) |
| { |
| /* No sections, have to look for phdrs. */ |
| size_t phnum; |
| if (unlikely (elf_getphdrnum (elf, &phnum) != 0)) |
| { |
| if (mod != NULL) |
| __libdwfl_seterrno (DWFL_E_LIBELF); |
| return -1; |
| } |
| for (size_t i = 0; result == 0 && i < phnum; ++i) |
| { |
| GElf_Phdr phdr_mem; |
| GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem); |
| if (likely (phdr != NULL) && phdr->p_type == PT_NOTE) |
| result = check_notes (elf_getdata_rawchunk (elf, |
| phdr->p_offset, |
| phdr->p_filesz, |
| ELF_T_NHDR), |
| phdr->p_vaddr, |
| build_id_bits, |
| build_id_elfaddr, |
| build_id_len); |
| } |
| } |
| else |
| do |
| { |
| GElf_Shdr shdr_mem; |
| GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); |
| if (likely (shdr != NULL) && shdr->sh_type == SHT_NOTE) |
| { |
| /* Determine the right sh_addr in this module. */ |
| GElf_Addr vaddr = 0; |
| if (!(shdr->sh_flags & SHF_ALLOC)) |
| vaddr = NO_VADDR; |
| else if (mod == NULL || e_type != ET_REL) |
| vaddr = shdr->sh_addr; |
| else if (__libdwfl_relocate_value (mod, elf, &shstrndx, |
| elf_ndxscn (scn), &vaddr)) |
| vaddr = NO_VADDR; |
| result = check_notes (elf_getdata (scn, NULL), vaddr, |
| build_id_bits, |
| build_id_elfaddr, |
| build_id_len); |
| } |
| } |
| while (result == 0 && (scn = elf_nextscn (elf, scn)) != NULL); |
| |
| return result; |
| } |
| |
| int |
| internal_function |
| __libdwfl_find_elf_build_id (Dwfl_Module *mod, Elf *elf, |
| const void **build_id_bits, |
| GElf_Addr *build_id_elfaddr, int *build_id_len) |
| { |
| GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem); |
| if (unlikely (ehdr == NULL)) |
| { |
| __libdwfl_seterrno (DWFL_E_LIBELF); |
| return -1; |
| } |
| // MOD->E_TYPE is zero here. |
| assert (ehdr->e_type != ET_REL || mod != NULL); |
| |
| return find_elf_build_id (mod, ehdr->e_type, elf, |
| build_id_bits, build_id_elfaddr, build_id_len); |
| } |
| |
| ssize_t |
| dwelf_elf_gnu_build_id (Elf *elf, const void **build_idp) |
| { |
| GElf_Addr build_id_elfaddr; |
| int build_id_len; |
| int result = find_elf_build_id (NULL, ET_NONE, elf, build_idp, |
| &build_id_elfaddr, &build_id_len); |
| if (result > 0) |
| return build_id_len; |
| |
| return result; |
| } |
| INTDEF(dwelf_elf_gnu_build_id) |