137 lines
3.7 KiB
C
137 lines
3.7 KiB
C
/*
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* Copyright © 2016 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifdef HAVE_DL_ITERATE_PHDR
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#include <dlfcn.h>
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#include <link.h>
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#include <stddef.h>
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#include <string.h>
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#include "build_id.h"
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#include "macros.h"
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#ifndef NT_GNU_BUILD_ID
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#define NT_GNU_BUILD_ID 3
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#endif
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#ifndef ElfW
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#define ElfW(type) Elf_##type
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#endif
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struct build_id_note {
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ElfW(Nhdr) nhdr;
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char name[4]; /* Note name for build-id is "GNU\0" */
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uint8_t build_id[0];
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};
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struct callback_data {
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/* Base address of shared object, taken from Dl_info::dli_fbase */
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const void *dli_fbase;
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struct build_id_note *note;
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};
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static int
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build_id_find_nhdr_callback(struct dl_phdr_info *info, size_t size, void *data_)
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{
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struct callback_data *data = data_;
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/* Calculate address where shared object is mapped into the process space.
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* (Using the base address and the virtual address of the first LOAD segment)
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*/
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void *map_start = NULL;
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for (unsigned i = 0; i < info->dlpi_phnum; i++) {
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if (info->dlpi_phdr[i].p_type == PT_LOAD) {
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map_start = (void *)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
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break;
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}
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}
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if (map_start != data->dli_fbase)
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return 0;
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for (unsigned i = 0; i < info->dlpi_phnum; i++) {
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if (info->dlpi_phdr[i].p_type != PT_NOTE)
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continue;
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struct build_id_note *note = (void *)(info->dlpi_addr +
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info->dlpi_phdr[i].p_vaddr);
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ptrdiff_t len = info->dlpi_phdr[i].p_filesz;
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while (len >= sizeof(struct build_id_note)) {
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if (note->nhdr.n_type == NT_GNU_BUILD_ID &&
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note->nhdr.n_descsz != 0 &&
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note->nhdr.n_namesz == 4 &&
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memcmp(note->name, "GNU", 4) == 0) {
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data->note = note;
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return 1;
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}
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size_t offset = sizeof(ElfW(Nhdr)) +
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ALIGN_POT(note->nhdr.n_namesz, 4) +
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ALIGN_POT(note->nhdr.n_descsz, 4);
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note = (struct build_id_note *)((char *)note + offset);
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len -= offset;
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}
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}
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return 0;
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}
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const struct build_id_note *
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build_id_find_nhdr_for_addr(const void *addr)
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{
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Dl_info info;
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if (!dladdr(addr, &info))
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return NULL;
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if (!info.dli_fbase)
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return NULL;
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struct callback_data data = {
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.dli_fbase = info.dli_fbase,
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.note = NULL,
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};
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if (!dl_iterate_phdr(build_id_find_nhdr_callback, &data))
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return NULL;
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return data.note;
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}
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unsigned
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build_id_length(const struct build_id_note *note)
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{
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return note->nhdr.n_descsz;
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}
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const uint8_t *
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build_id_data(const struct build_id_note *note)
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{
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return note->build_id;
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}
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#endif
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