+++ /dev/null
-/*
- * Copyright (C) 2015 Antoine Busque <abusque@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <helper.h>
-#include <string.h>
-#include <lttng/align.h>
-#include <lttng/ust-elf.h>
-
-/*
- * Retrieve the nth (where n is the `index` argument) phdr (program
- * header) from the given elf instance.
- *
- * A pointer to the phdr is returned on success, NULL on failure.
- */
-static
-struct lttng_ust_elf_phdr *lttng_ust_elf_get_phdr(struct lttng_ust_elf *elf,
- uint16_t index)
-{
- struct lttng_ust_elf_phdr *phdr = NULL;
- long offset;
-
- if (!elf) {
- goto error;
- }
-
- if (index >= elf->ehdr->e_phnum) {
- goto error;
- }
-
- phdr = zmalloc(sizeof(struct lttng_ust_elf_phdr));
- if (!phdr) {
- goto error;
- }
-
- offset = elf->ehdr->e_phoff + index * elf->ehdr->e_phentsize;
- if (fseek(elf->file, offset, SEEK_SET)) {
- goto error;
- }
-
- if (is_elf_32_bit(elf)) {
- Elf32_Phdr elf_phdr;
-
- if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_phdr(elf_phdr);
- }
- copy_phdr(elf_phdr, *phdr);
- } else {
- Elf64_Phdr elf_phdr;
-
- if (!fread(&elf_phdr, sizeof(elf_phdr), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_phdr(elf_phdr);
- }
- copy_phdr(elf_phdr, *phdr);
- }
-
- return phdr;
-
-error:
- free(phdr);
- return NULL;
-}
-
-/*
- * Retrieve the nth (where n is the `index` argument) shdr (section
- * header) from the given elf instance.
- *
- * A pointer to the shdr is returned on success, NULL on failure.
- */
-static
-struct lttng_ust_elf_shdr *lttng_ust_elf_get_shdr(struct lttng_ust_elf *elf,
- uint16_t index)
-{
- struct lttng_ust_elf_shdr *shdr = NULL;
- long offset;
-
- if (!elf) {
- goto error;
- }
-
- if (index >= elf->ehdr->e_shnum) {
- goto error;
- }
-
- shdr = zmalloc(sizeof(struct lttng_ust_elf_shdr));
- if (!shdr) {
- goto error;
- }
-
- offset = elf->ehdr->e_shoff + index * elf->ehdr->e_shentsize;
- if (fseek(elf->file, offset, SEEK_SET)) {
- goto error;
- }
-
- if (is_elf_32_bit(elf)) {
- Elf32_Shdr elf_shdr;
-
- if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_shdr(elf_shdr);
- }
- copy_shdr(elf_shdr, *shdr);
- } else {
- Elf64_Shdr elf_shdr;
-
- if (!fread(&elf_shdr, sizeof(elf_shdr), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_shdr(elf_shdr);
- }
- copy_shdr(elf_shdr, *shdr);
- }
-
- return shdr;
-
-error:
- free(shdr);
- return NULL;
-}
-
-/*
- * Lookup a section's name from a given offset (usually from an shdr's
- * sh_name value) in bytes relative to the beginning of the section
- * names string table.
- *
- * If no name is found, NULL is returned.
- */
-static
-char *lttng_ust_elf_get_section_name(struct lttng_ust_elf *elf, uint32_t offset)
-{
- char *name = NULL;
- size_t len;
-
- if (!elf) {
- goto error;
- }
-
- if (offset >= elf->section_names_size) {
- goto error;
- }
-
- if (fseek(elf->file, elf->section_names_offset + offset, SEEK_SET)) {
- goto error;
- }
- /* Note that len starts at 1, it is not an index. */
- for (len = 1; offset + len <= elf->section_names_size; ++len) {
- switch (fgetc(elf->file)) {
- case EOF:
- goto error;
- case '\0':
- goto end;
- default:
- break;
- }
- }
-
- /* No name was found before the end of the table. */
- goto error;
-
-end:
- name = zmalloc(sizeof(char) * len);
- if (!name) {
- goto error;
- }
- if (fseek(elf->file, elf->section_names_offset + offset,
- SEEK_SET)) {
- goto error;
- }
- if (!fgets(name, len, elf->file)) {
- goto error;
- }
-
- return name;
-
-error:
- free(name);
- return NULL;
-}
-
-/*
- * Create an instance of lttng_ust_elf for the ELF file located at
- * `path`.
- *
- * Return a pointer to the instance on success, NULL on failure.
- */
-struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
-{
- uint8_t e_ident[EI_NIDENT];
- struct lttng_ust_elf_shdr *section_names_shdr;
- struct lttng_ust_elf *elf;
-
- elf = zmalloc(sizeof(struct lttng_ust_elf));
- if (!elf) {
- goto error;
- }
-
- elf->path = strdup(path);
- if (!elf->path) {
- goto error;
- }
-
- elf->file = fopen(elf->path, "rb");
- if (!elf->file) {
- goto error;
- }
-
- if (!fread(e_ident, 1, EI_NIDENT, elf->file)) {
- goto error;
- }
- elf->bitness = e_ident[EI_CLASS];
- elf->endianness = e_ident[EI_DATA];
- rewind(elf->file);
-
- elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr));
- if (!elf->ehdr) {
- goto error;
- }
-
- if (is_elf_32_bit(elf)) {
- Elf32_Ehdr elf_ehdr;
-
- if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_ehdr(elf_ehdr);
- }
- copy_ehdr(elf_ehdr, *(elf->ehdr));
- } else {
- Elf64_Ehdr elf_ehdr;
-
- if (!fread(&elf_ehdr, sizeof(elf_ehdr), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_ehdr(elf_ehdr);
- }
- copy_ehdr(elf_ehdr, *(elf->ehdr));
- }
-
- section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx);
- if (!section_names_shdr) {
- goto error;
- }
-
- elf->section_names_offset = section_names_shdr->sh_offset;
- elf->section_names_size = section_names_shdr->sh_size;
-
- free(section_names_shdr);
-
- return elf;
-
-error:
- if (elf) {
- free(elf->ehdr);
- fclose(elf->file);
- free(elf->path);
- }
- free(elf);
- return NULL;
-}
-
-/*
- * Destroy the given lttng_ust_elf instance.
- */
-void lttng_ust_elf_destroy(struct lttng_ust_elf *elf)
-{
- if (!elf) {
- return;
- }
-
- free(elf->ehdr);
- fclose(elf->file);
- free(elf->path);
- free(elf);
-}
-
-/*
- * Compute the total in-memory size of the ELF file, in bytes.
- *
- * Returns 0 if successful, -1 if not. On success, the memory size is
- * returned through the out parameter `memsz`.
- */
-int lttng_ust_elf_get_memsz(struct lttng_ust_elf *elf, uint64_t *memsz)
-{
- uint16_t i;
- uint64_t _memsz = 0;
-
- if (!elf || !memsz) {
- goto error;
- }
-
- for (i = 0; i < elf->ehdr->e_phnum; ++i) {
- struct lttng_ust_elf_phdr *phdr;
- uint64_t align;
-
- phdr = lttng_ust_elf_get_phdr(elf, i);
- if (!phdr) {
- goto error;
- }
-
- /*
- * Only PT_LOAD segments contribute to memsz. Skip
- * other segments.
- */
- if (phdr->p_type != PT_LOAD) {
- goto next_loop;
- }
-
- /*
- * A p_align of 0 means no alignment, i.e. aligned to
- * 1 byte.
- */
- align = phdr->p_align == 0 ? 1 : phdr->p_align;
- /* Align the start of the segment. */
- _memsz += offset_align(_memsz, align);
- _memsz += phdr->p_memsz;
- /*
- * Add padding at the end of the segment, so it ends
- * on a multiple of the align value (which usually
- * means a page boundary). This makes the computation
- * valid even in cases where p_align would change from
- * one segment to the next.
- */
- _memsz += offset_align(_memsz, align);
- next_loop:
- free(phdr);
- }
-
- *memsz = _memsz;
- return 0;
-error:
- return -1;
-}
-
-/*
- * Internal method used to try and get the build_id from a PT_NOTE
- * segment ranging from `offset` to `segment_end`.
- *
- * If the function returns successfully, the out parameter `found`
- * indicates whether the build id information was present in the
- * segment or not. If `found` is not 0, the out parameters `build_id`
- * and `length` will both have been set with the retrieved
- * information.
- *
- * Returns 0 on success, -1 if an error occurred.
- */
-static
-int lttng_ust_elf_get_build_id_from_segment(
- struct lttng_ust_elf *elf, uint8_t **build_id, size_t *length,
- uint64_t offset, uint64_t segment_end, int *found)
-{
- uint8_t *_build_id;
- size_t _length;
- int _found = 0;
-
- while (offset < segment_end) {
- struct lttng_ust_elf_nhdr nhdr;
-
- /* Align start of note entry */
- offset += offset_align(offset, ELF_NOTE_ENTRY_ALIGN);
- if (offset >= segment_end) {
- break;
- }
- /*
- * We seek manually because if the note isn't the
- * build id the data following the header will not
- * have been read.
- */
- if (fseek(elf->file, offset, SEEK_SET)) {
- goto error;
- }
- if (!fread(&nhdr, sizeof(nhdr), 1, elf->file)) {
- goto error;
- }
-
- if (!is_elf_native_endian(elf)) {
- nhdr.n_namesz = bswap_32(nhdr.n_namesz);
- nhdr.n_descsz = bswap_32(nhdr.n_descsz);
- nhdr.n_type = bswap_32(nhdr.n_type);
- }
-
- offset += sizeof(nhdr) + nhdr.n_namesz;
- /* Align start of desc entry */
- offset += offset_align(offset, ELF_NOTE_DESC_ALIGN);
-
- if (nhdr.n_type != NT_GNU_BUILD_ID) {
- /*
- * Ignore non build id notes but still
- * increase the offset.
- */
- offset += nhdr.n_descsz;
- continue;
- }
-
- _length = nhdr.n_descsz;
- _build_id = zmalloc(sizeof(uint8_t) * _length);
- if (!build_id) {
- goto error;
- }
-
- if (fseek(elf->file, offset, SEEK_SET)) {
- goto error;
- }
- if (!fread(_build_id, sizeof(*_build_id), _length, elf->file)) {
- goto error;
- }
-
- _found = 1;
- break;
- }
-
- if (_found) {
- *build_id = _build_id;
- *length = _length;
- }
-
- *found = _found;
- return 0;
-error:
- return -1;
-}
-
-/*
- * Retrieve a build ID (an array of bytes) from the corresponding
- * section in the ELF file. The length of the build ID can be either
- * 16 or 20 bytes depending on the method used to generate it, hence
- * the length out parameter.
- *
- * If the function returns successfully, the out parameter `found`
- * indicates whether the build id information was present in the ELF
- * file or not. If `found` is not 0, the out parameters `build_id` and
- * `length` will both have been set with the retrieved information.
- *
- * Returns 0 on success, -1 if an error occurred.
- */
-int lttng_ust_elf_get_build_id(struct lttng_ust_elf *elf, uint8_t **build_id,
- size_t *length, int *found)
-{
- uint16_t i;
- uint8_t *_build_id;
- size_t _length;
- int _found = 0;
-
- if (!elf || !build_id || !length || !found) {
- goto error;
- }
-
- for (i = 0; i < elf->ehdr->e_phnum; ++i) {
- uint64_t offset, segment_end;
- struct lttng_ust_elf_phdr *phdr;
- int ret;
-
- phdr = lttng_ust_elf_get_phdr(elf, i);
- if (!phdr) {
- goto error;
- }
-
- /* Build ID will be contained in a PT_NOTE segment. */
- if (phdr->p_type != PT_NOTE) {
- goto next_loop;
- }
-
- offset = phdr->p_offset;
- segment_end = offset + phdr->p_filesz;
- ret = lttng_ust_elf_get_build_id_from_segment(
- elf, &_build_id, &_length, offset, segment_end,
- &_found);
- next_loop:
- free(phdr);
- if (ret) {
- goto error;
- }
- if (_found) {
- break;
- }
- }
-
- if (_found) {
- *build_id = _build_id;
- *length = _length;
- }
-
- *found = _found;
- return 0;
-error:
- return -1;
-}
-
-/*
- * Try to retrieve filename and CRC from given ELF section `shdr`.
- *
- * If the function returns successfully, the out parameter `found`
- * indicates whether the debug link information was present in the ELF
- * section or not. If `found` is not 0, the out parameters `filename` and
- * `crc` will both have been set with the retrieved information.
- *
- * Returns 0 on success, -1 if an error occurred.
- */
-static
-int lttng_ust_elf_get_debug_link_from_section(struct lttng_ust_elf *elf,
- char **filename, uint32_t *crc,
- int *found,
- struct lttng_ust_elf_shdr *shdr)
-{
- int _found = 0;
- char *_filename;
- char *section_name = NULL;
- uint32_t _crc;
-
- if (!elf || !filename || !crc || !found || !shdr) {
- goto error;
- }
-
- /*
- * The .gnu_debuglink section is of type SHT_PROGBITS,
- * skip the other sections.
- */
- if (shdr->sh_type != SHT_PROGBITS) {
- goto end;
- }
-
- section_name = lttng_ust_elf_get_section_name(elf,
- shdr->sh_name);
- if (!section_name) {
- goto end;
- }
- if (strcmp(section_name, ".gnu_debuglink")) {
- goto end;
- }
-
- /*
- * The length of the filename is the sh_size excluding the CRC
- * which comes after it in the section.
- */
- _filename = zmalloc(sizeof(char) * (shdr->sh_size - ELF_CRC_SIZE));
- if (!_filename) {
- goto error;
- }
- if (fseek(elf->file, shdr->sh_offset, SEEK_SET)) {
- goto error;
- }
- if (!fread(_filename, sizeof(*_filename), shdr->sh_size - ELF_CRC_SIZE,
- elf->file)) {
- goto error;
- }
- if (!fread(&_crc, sizeof(_crc), 1, elf->file)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- _crc = bswap_32(_crc);
- }
-
- _found = 1;
-
-end:
- free(section_name);
- if (_found) {
- *filename = _filename;
- *crc = _crc;
- }
- *found = _found;
-
- return 0;
-
-error:
- if (section_name) {
- free(section_name);
- }
-
- return -1;
-}
-
-/*
- * Retrieve filename and CRC from ELF's .gnu_debuglink section, if any.
- *
- * If the function returns successfully, the out parameter `found`
- * indicates whether the debug link information was present in the ELF
- * file or not. If `found` is not 0, the out parameters `filename` and
- * `crc` will both have been set with the retrieved information.
- *
- * Returns 0 on success, -1 if an error occurred.
- */
-int lttng_ust_elf_get_debug_link(struct lttng_ust_elf *elf, char **filename,
- uint32_t *crc, int *found)
-{
- int ret;
- uint16_t i;
- int _found = 0;
- char *_filename;
- uint32_t _crc;
-
- if (!elf || !filename || !crc || !found) {
- goto error;
- }
-
- for (i = 0; i < elf->ehdr->e_shnum; ++i) {
- struct lttng_ust_elf_shdr *shdr = NULL;
-
- shdr = lttng_ust_elf_get_shdr(elf, i);
- if (!shdr) {
- goto error;
- }
-
- ret = lttng_ust_elf_get_debug_link_from_section(
- elf, &_filename, &_crc, &_found, shdr);
- free(shdr);
-
- if (ret) {
- goto error;
- }
- if (_found) {
- break;
- }
- }
-
- if (_found) {
- *filename = _filename;
- *crc = _crc;
- }
-
- *found = _found;
- return 0;
-error:
- return -1;
-}
projects / lttng-ust.git / blobdiff