X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-elf.c;h=3d6a9379f7a5e44b6837c01fbb5c72a92bd32162;hb=HEAD;hp=f5c4f1a1c4988e2e323981e491071e2572f5f527;hpb=8e2aed3f18adc14ec586ef717e396bcac4473dd7;p=lttng-ust.git diff --git a/liblttng-ust/lttng-ust-elf.c b/liblttng-ust/lttng-ust-elf.c deleted file mode 100644 index f5c4f1a1..00000000 --- a/liblttng-ust/lttng-ust-elf.c +++ /dev/null @@ -1,649 +0,0 @@ -/* - * Copyright (C) 2015 Antoine Busque - * - * 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 -#include -#include -#include - -/* - * 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; -}