X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-elf.c;h=3d6a9379f7a5e44b6837c01fbb5c72a92bd32162;hb=HEAD;hp=ebc231e0d80b2f27d2b2a88cf0c112050578b569;hpb=2adb7ad28124fdbc0ad61bcada1c7dbceb03e9ab;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 ebc231e0..00000000
--- a/liblttng-ust/lttng-ust-elf.c
+++ /dev/null
@@ -1,705 +0,0 @@
-/*
- * SPDX-License-Identifier: LGPL-2.1-or-later
- *
- * Copyright (C) 2015 Antoine Busque <abusque@efficios.com>
- */
-
-#define _LGPL_SOURCE
-#include <fcntl.h>
-#include <ust-helper.h>
-#include <lttng/align.h>
-#include <ust-elf.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.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.
- */
-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;
-}