+++ /dev/null
-/*
- * SPDX-License-Identifier: LGPL-2.1-or-later
- *
- * Copyright (C) 2015 Antoine Busque <abusque@efficios.com>
- */
-
-#define _LGPL_SOURCE
-#include <fcntl.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#include <lttng/ust-utils.h>
-
-#include <ust-elf.h>
-#include <ust-fd.h>
-
-#include "lttng-tracer-core.h"
-#include "lttng-ust-elf.h"
-#include "ust-helper.h"
-
-#define BUF_LEN 4096
-
-#ifndef NT_GNU_BUILD_ID
-# define NT_GNU_BUILD_ID 3
-#endif
-
-/*
- * 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;
- off_t 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 = (off_t) elf->ehdr->e_phoff
- + (off_t) index * elf->ehdr->e_phentsize;
- if (lseek(elf->fd, offset, SEEK_SET) < 0) {
- goto error;
- }
-
- if (is_elf_32_bit(elf)) {
- Elf32_Phdr elf_phdr;
-
- if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr))
- < sizeof(elf_phdr)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_phdr(elf_phdr);
- }
- copy_phdr(elf_phdr, *phdr);
- } else {
- Elf64_Phdr elf_phdr;
-
- if (lttng_ust_read(elf->fd, &elf_phdr, sizeof(elf_phdr))
- < sizeof(elf_phdr)) {
- 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;
- off_t 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 = (off_t) elf->ehdr->e_shoff
- + (off_t) index * elf->ehdr->e_shentsize;
- if (lseek(elf->fd, offset, SEEK_SET) < 0) {
- goto error;
- }
-
- if (is_elf_32_bit(elf)) {
- Elf32_Shdr elf_shdr;
-
- if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr))
- < sizeof(elf_shdr)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_shdr(elf_shdr);
- }
- copy_shdr(elf_shdr, *shdr);
- } else {
- Elf64_Shdr elf_shdr;
-
- if (lttng_ust_read(elf->fd, &elf_shdr, sizeof(elf_shdr))
- < sizeof(elf_shdr)) {
- 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, off_t offset)
-{
- char *name = NULL;
- size_t len = 0, to_read; /* len does not include \0 */
-
- if (!elf) {
- goto error;
- }
-
- if (offset >= elf->section_names_size) {
- goto error;
- }
-
- if (lseek(elf->fd, elf->section_names_offset + offset, SEEK_SET) < 0) {
- goto error;
- }
-
- to_read = elf->section_names_size - offset;
-
- /* Find first \0 after or at current location, remember len. */
- for (;;) {
- char buf[BUF_LEN];
- ssize_t read_len;
- size_t i;
-
- if (!to_read) {
- goto error;
- }
- read_len = lttng_ust_read(elf->fd, buf,
- min_t(size_t, BUF_LEN, to_read));
- if (read_len <= 0) {
- goto error;
- }
- for (i = 0; i < read_len; i++) {
- if (buf[i] == '\0') {
- len += i;
- goto end;
- }
- }
- len += read_len;
- to_read -= read_len;
- }
-end:
- name = zmalloc(sizeof(char) * (len + 1)); /* + 1 for \0 */
- if (!name) {
- goto error;
- }
- if (lseek(elf->fd, elf->section_names_offset + offset,
- SEEK_SET) < 0) {
- goto error;
- }
- if (lttng_ust_read(elf->fd, name, len + 1) < len + 1) {
- 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 = NULL;
- int ret, fd;
-
- elf = zmalloc(sizeof(struct lttng_ust_elf));
- if (!elf) {
- goto error;
- }
-
- /* Initialize fd field to -1. 0 is a valid fd number */
- elf->fd = -1;
-
- elf->path = strdup(path);
- if (!elf->path) {
- goto error;
- }
-
- lttng_ust_lock_fd_tracker();
- fd = open(elf->path, O_RDONLY | O_CLOEXEC);
- if (fd < 0) {
- lttng_ust_unlock_fd_tracker();
- goto error;
- }
-
- ret = lttng_ust_add_fd_to_tracker(fd);
- if (ret < 0) {
- ret = close(fd);
- if (ret) {
- PERROR("close on elf->fd");
- }
- ret = -1;
- lttng_ust_unlock_fd_tracker();
- goto error;
- }
- elf->fd = ret;
- lttng_ust_unlock_fd_tracker();
-
- if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) {
- goto error;
- }
- elf->bitness = e_ident[EI_CLASS];
- elf->endianness = e_ident[EI_DATA];
-
- if (lseek(elf->fd, 0, SEEK_SET) < 0) {
- goto error;
- }
-
- 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 (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
- < sizeof(elf_ehdr)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- bswap_ehdr(elf_ehdr);
- }
- copy_ehdr(elf_ehdr, *(elf->ehdr));
- } else {
- Elf64_Ehdr elf_ehdr;
-
- if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
- < sizeof(elf_ehdr)) {
- 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:
- lttng_ust_elf_destroy(elf);
- return NULL;
-}
-
-/*
- * Test whether the ELF file is position independent code (PIC)
- */
-uint8_t lttng_ust_elf_is_pic(struct lttng_ust_elf *elf)
-{
- /*
- * PIC has and e_type value of ET_DYN, see ELF specification
- * version 1.1 p. 1-3.
- */
- return elf->ehdr->e_type == ET_DYN;
-}
-
-/*
- * Destroy the given lttng_ust_elf instance.
- */
-void lttng_ust_elf_destroy(struct lttng_ust_elf *elf)
-{
- int ret;
-
- if (!elf) {
- return;
- }
-
- if (elf->fd >= 0) {
- lttng_ust_lock_fd_tracker();
- ret = close(elf->fd);
- if (!ret) {
- lttng_ust_delete_fd_from_tracker(elf->fd);
- } else {
- PERROR("close");
- abort();
- }
- lttng_ust_unlock_fd_tracker();
- }
-
- free(elf->ehdr);
- 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 low_addr = UINT64_MAX, high_addr = 0;
-
- if (!elf || !memsz) {
- goto error;
- }
-
- for (i = 0; i < elf->ehdr->e_phnum; ++i) {
- struct lttng_ust_elf_phdr *phdr;
-
- 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;
- }
-
- low_addr = min_t(uint64_t, low_addr, phdr->p_vaddr);
- high_addr = max_t(uint64_t, high_addr,
- phdr->p_vaddr + phdr->p_memsz);
- next_loop:
- free(phdr);
- }
-
- if (high_addr < low_addr) {
- /* No PT_LOAD segments or corrupted data. */
- goto error;
- }
-
- *memsz = high_addr - low_addr;
- 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,
- off_t offset, off_t segment_end)
-{
- uint8_t *_build_id = NULL; /* Silence old gcc warning. */
- size_t _length = 0; /* Silence old gcc warning. */
-
- while (offset < segment_end) {
- struct lttng_ust_elf_nhdr nhdr;
- size_t read_len;
-
- /* Align start of note entry */
- offset += lttng_ust_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 (lseek(elf->fd, offset, SEEK_SET) < 0) {
- goto error;
- }
- if (lttng_ust_read(elf->fd, &nhdr, sizeof(nhdr))
- < sizeof(nhdr)) {
- 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 += lttng_ust_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 (lseek(elf->fd, offset, SEEK_SET) < 0) {
- goto error;
- }
- read_len = sizeof(*_build_id) * _length;
- if (lttng_ust_read(elf->fd, _build_id, read_len) < read_len) {
- goto error;
- }
-
- break;
- }
-
- if (_build_id) {
- *build_id = _build_id;
- *length = _length;
- }
-
- return 0;
-error:
- free(_build_id);
- 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 = NULL; /* Silence old gcc warning. */
- size_t _length = 0; /* Silence old gcc warning. */
-
- if (!elf || !build_id || !length || !found) {
- goto error;
- }
-
- for (i = 0; i < elf->ehdr->e_phnum; ++i) {
- off_t offset, segment_end;
- struct lttng_ust_elf_phdr *phdr;
- int ret = 0;
-
- 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);
- next_loop:
- free(phdr);
- if (ret) {
- goto error;
- }
- if (_build_id) {
- break;
- }
- }
-
- if (_build_id) {
- *build_id = _build_id;
- *length = _length;
- *found = 1;
- } else {
- *found = 0;
- }
-
- return 0;
-error:
- free(_build_id);
- 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,
- struct lttng_ust_elf_shdr *shdr)
-{
- char *_filename = NULL; /* Silence old gcc warning. */
- size_t filename_len;
- char *section_name = NULL;
- uint32_t _crc = 0; /* Silence old gcc warning. */
-
- if (!elf || !filename || !crc || !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 (lseek(elf->fd, shdr->sh_offset, SEEK_SET) < 0) {
- goto error;
- }
- filename_len = sizeof(*_filename) * (shdr->sh_size - ELF_CRC_SIZE);
- if (lttng_ust_read(elf->fd, _filename, filename_len) < filename_len) {
- goto error;
- }
- if (lttng_ust_read(elf->fd, &_crc, sizeof(_crc)) < sizeof(_crc)) {
- goto error;
- }
- if (!is_elf_native_endian(elf)) {
- _crc = bswap_32(_crc);
- }
-
-end:
- free(section_name);
- if (_filename) {
- *filename = _filename;
- *crc = _crc;
- }
-
- return 0;
-
-error:
- free(_filename);
- 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;
- char *_filename = NULL; /* Silence old gcc warning. */
- uint32_t _crc = 0; /* Silence old gcc warning. */
-
- 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, shdr);
- free(shdr);
-
- if (ret) {
- goto error;
- }
- if (_filename) {
- break;
- }
- }
-
- if (_filename) {
- *filename = _filename;
- *crc = _crc;
- *found = 1;
- } else {
- *found = 0;
- }
-
- return 0;
-
-error:
- free(_filename);
- return -1;
-}
projects / lttng-ust.git / blobdiff