| /* |
| * Copyright © 2016 Intel Corporation |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| */ |
| |
| #ifdef HAVE_DL_ITERATE_PHDR |
| #include <link.h> |
| #include <stddef.h> |
| #include <string.h> |
| |
| #include "build_id.h" |
| |
| #ifndef NT_GNU_BUILD_ID |
| #define NT_GNU_BUILD_ID 3 |
| #endif |
| |
| #ifndef ElfW |
| #define ElfW(type) Elf_##type |
| #endif |
| |
| #define ALIGN(val, align) (((val) + (align) - 1) & ~((align) - 1)) |
| |
| struct build_id_note { |
| ElfW(Nhdr) nhdr; |
| |
| char name[4]; /* Note name for build-id is "GNU\0" */ |
| uint8_t build_id[0]; |
| }; |
| |
| struct callback_data { |
| const char *filename; |
| struct build_id_note *note; |
| }; |
| |
| static int |
| build_id_find_nhdr_callback(struct dl_phdr_info *info, size_t size, void *data_) |
| { |
| struct callback_data *data = data_; |
| |
| /* The first object visited by callback is the main program. |
| * Android's libc returns a NULL pointer for the first executable. |
| */ |
| if (info->dlpi_name == NULL) |
| return 0; |
| |
| char *ptr = strstr(info->dlpi_name, data->filename); |
| if (ptr == NULL || ptr[strlen(data->filename)] != '\0') |
| return 0; |
| |
| for (unsigned i = 0; i < info->dlpi_phnum; i++) { |
| if (info->dlpi_phdr[i].p_type != PT_NOTE) |
| continue; |
| |
| struct build_id_note *note = (void *)(info->dlpi_addr + |
| info->dlpi_phdr[i].p_vaddr); |
| ptrdiff_t len = info->dlpi_phdr[i].p_filesz; |
| |
| while (len >= sizeof(struct build_id_note)) { |
| if (note->nhdr.n_type == NT_GNU_BUILD_ID && |
| note->nhdr.n_descsz != 0 && |
| note->nhdr.n_namesz == 4 && |
| memcmp(note->name, "GNU", 4) == 0) { |
| data->note = note; |
| return 1; |
| } |
| |
| size_t offset = sizeof(ElfW(Nhdr)) + |
| ALIGN(note->nhdr.n_namesz, 4) + |
| ALIGN(note->nhdr.n_descsz, 4); |
| note = (struct build_id_note *)((char *)note + offset); |
| len -= offset; |
| } |
| } |
| |
| return 0; |
| } |
| |
| const struct build_id_note * |
| build_id_find_nhdr(const char *filename) |
| { |
| struct callback_data data = { |
| .filename = filename, |
| .note = NULL, |
| }; |
| |
| if (!dl_iterate_phdr(build_id_find_nhdr_callback, &data)) |
| return NULL; |
| |
| return data.note; |
| } |
| |
| unsigned |
| build_id_length(const struct build_id_note *note) |
| { |
| return note->nhdr.n_descsz; |
| } |
| |
| const uint8_t * |
| build_id_data(const struct build_id_note *note) |
| { |
| return note->build_id; |
| } |
| |
| #endif |