--- /dev/null
+/*
+ * bin-info.c
+ *
+ * Babeltrace - Executable and Shared Object Debug Info Reader
+ *
+ * Copyright 2015 Antoine Busque <abusque@efficios.com>
+ *
+ * Author: Antoine Busque <abusque@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#define BT_LOG_TAG "PLUGIN-CTF-LTTNG-UTILS-DEBUG-INFO-FLT-BIN-INFO"
+#include "logging.h"
+
+#include <dwarf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <libgen.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <glib.h>
+
+#include "common/common.h"
+
+#include "bin-info.h"
+#include "crc32.h"
+#include "dwarf.h"
+#include "utils.h"
+
+/*
+ * An address printed in hex is at most 20 bytes (16 for 64-bits +
+ * leading 0x + optional leading '+' if addr is an offset + null
+ * character).
+ */
+#define ADDR_STR_LEN 20
+#define BUILD_ID_NOTE_NAME "GNU"
+
+BT_HIDDEN
+int bin_info_init(void)
+{
+ int ret = 0;
+
+ if (elf_version(EV_CURRENT) == EV_NONE) {
+ BT_LOGD("ELF library initialization failed: %s.",
+ elf_errmsg(-1));
+ ret = -1;
+ }
+
+ return ret;
+}
+
+BT_HIDDEN
+struct bin_info *bin_info_create(struct bt_fd_cache *fdc, const char *path,
+ uint64_t low_addr, uint64_t memsz, bool is_pic,
+ const char *debug_info_dir, const char *target_prefix)
+{
+ struct bin_info *bin = NULL;
+
+ BT_ASSERT(fdc);
+
+ if (!path) {
+ goto error;
+ }
+
+ bin = g_new0(struct bin_info, 1);
+ if (!bin) {
+ goto error;
+ }
+
+ if (target_prefix) {
+ bin->elf_path = g_build_filename(target_prefix, path, NULL);
+ } else {
+ bin->elf_path = g_strdup(path);
+ }
+
+ if (!bin->elf_path) {
+ goto error;
+ }
+
+ if (debug_info_dir) {
+ bin->debug_info_dir = g_strdup(debug_info_dir);
+ if (!bin->debug_info_dir) {
+ goto error;
+ }
+ }
+
+ bin->is_pic = is_pic;
+ bin->memsz = memsz;
+ bin->low_addr = low_addr;
+ bin->high_addr = bin->low_addr + bin->memsz;
+ bin->build_id = NULL;
+ bin->build_id_len = 0;
+ bin->file_build_id_matches = false;
+ bin->fd_cache = fdc;
+
+ return bin;
+
+error:
+ bin_info_destroy(bin);
+ return NULL;
+}
+
+BT_HIDDEN
+void bin_info_destroy(struct bin_info *bin)
+{
+ if (!bin) {
+ return;
+ }
+
+ dwarf_end(bin->dwarf_info);
+
+ g_free(bin->debug_info_dir);
+ g_free(bin->elf_path);
+ g_free(bin->dwarf_path);
+ g_free(bin->build_id);
+ g_free(bin->dbg_link_filename);
+
+ elf_end(bin->elf_file);
+
+ bt_fd_cache_put_handle(bin->fd_cache, bin->elf_handle);
+ bt_fd_cache_put_handle(bin->fd_cache, bin->dwarf_handle);
+
+ g_free(bin);
+}
+
+/**
+ * Initialize the ELF file for a given executable.
+ *
+ * @param bin bin_info instance
+ * @returns 0 on success, negative value on error.
+ */
+static
+int bin_info_set_elf_file(struct bin_info *bin)
+{
+ struct bt_fd_cache_handle *elf_handle = NULL;
+ Elf *elf_file = NULL;
+
+ if (!bin) {
+ goto error;
+ }
+
+ elf_handle = bt_fd_cache_get_handle(bin->fd_cache, bin->elf_path);
+ if (!elf_handle) {
+ BT_LOGD("Failed to open %s", bin->elf_path);
+ goto error;
+ }
+ bin->elf_handle = elf_handle;
+
+ elf_file = elf_begin(bt_fd_cache_handle_get_fd(bin->elf_handle),
+ ELF_C_READ, NULL);
+ if (!elf_file) {
+ BT_LOGE("elf_begin failed: %s", elf_errmsg(-1));
+ goto error;
+ }
+
+ bin->elf_file = elf_file;
+
+ if (elf_kind(elf_file) != ELF_K_ELF) {
+ BT_LOGE("Error: %s is not an ELF object", bin->elf_path);
+ goto error;
+ }
+
+ return 0;
+
+error:
+ bt_fd_cache_put_handle(bin->fd_cache, elf_handle);
+ elf_end(elf_file);
+ return -1;
+}
+
+/**
+ * From a note section data struct, check if it is a build id note.
+ *
+ * @param note_data Pointer to a note section
+ *
+ * @returns 1 on match, 0 if `buf` does not contain a
+ * valid build id note
+ */
+static
+int is_build_id_note_section(Elf_Data *note_data)
+{
+ size_t name_offset, desc_offset;
+ GElf_Nhdr note_header;
+ int ret = 0;
+
+ /*
+ * Discard the return value as it contains the size of the note section
+ * and we don't need it.
+ */
+ (void) gelf_getnote(note_data, 0, ¬e_header, &name_offset,
+ &desc_offset);
+
+ /*
+ * Check the note name length. The name_sz field includes the
+ * terminating null byte.
+ */
+ if (note_header.n_namesz != sizeof(BUILD_ID_NOTE_NAME)) {
+ goto invalid;
+ }
+
+ /* Check the note type. */
+ if (note_header.n_type != NT_GNU_BUILD_ID) {
+ goto invalid;
+ }
+
+ /* Check the note name. */
+ if (memcmp(note_data->d_buf + name_offset, BUILD_ID_NOTE_NAME,
+ note_header.n_namesz) != 0) {
+ goto invalid;
+ }
+
+ ret = 1;
+
+invalid:
+ return ret;
+}
+
+/**
+ * From a build id note section data struct, check if the build id it contains
+ * is identical to the build id passed as parameter.
+ *
+ * @param note_data Pointer to the file build id note section.
+ * @param build_id Pointer to a build id to compare to.
+ * @param build_id_len length of the build id.
+ *
+ * @returns 1 on match, 0 otherwise.
+ */
+static
+int is_build_id_note_section_matching(Elf_Data *note_data,
+ uint8_t *build_id, size_t build_id_len)
+{
+ size_t name_offset, desc_offset;
+ GElf_Nhdr note_header;
+
+ if (build_id_len <= 0) {
+ goto end;
+ }
+
+ /*
+ * Discard the return value as it contains the size of the note section
+ * and we don't need it.
+ */
+ (void) gelf_getnote(note_data, 0, ¬e_header, &name_offset,
+ &desc_offset);
+
+ /*
+ * Compare the binary build id with the supplied build id.
+ */
+ if (memcmp(build_id, note_data->d_buf + desc_offset,
+ build_id_len) == 0) {
+ return 1;
+ }
+end:
+ return 0;
+}
+
+/**
+ * Checks if the build id stored in `bin` (bin->build_id) is matching the build
+ * id of the ondisk file (bin->elf_file).
+ *
+ * @param bin bin_info instance
+ * @param build_id build id to compare ot the on disk file
+ * @param build_id_len length of the build id
+ *
+ * @returns 1 on if the build id of stored in `bin` matches
+ * the build id of the ondisk file.
+ * 0 on if they are different or an error occured.
+ */
+static
+int is_build_id_matching(struct bin_info *bin)
+{
+ int ret, is_build_id, is_matching = 0;
+ Elf_Scn *curr_section = NULL, *next_section = NULL;
+ GElf_Shdr curr_section_hdr;
+
+ if (!bin->build_id) {
+ goto error;
+ }
+
+ /* Set ELF file if it hasn't been accessed yet. */
+ if (!bin->elf_file) {
+ ret = bin_info_set_elf_file(bin);
+ if (ret) {
+ /* Failed to set ELF file. */
+ goto error;
+ }
+ }
+
+ next_section = elf_nextscn(bin->elf_file, curr_section);
+ if (!next_section) {
+ goto error;
+ }
+
+ while (next_section) {
+ Elf_Data *note_data = NULL;
+
+ curr_section = next_section;
+ next_section = elf_nextscn(bin->elf_file, curr_section);
+
+ if (!gelf_getshdr(curr_section, &curr_section_hdr)) {
+ goto error;
+ }
+
+ if (curr_section_hdr.sh_type != SHT_NOTE) {
+ continue;
+ }
+
+ /*
+ * elf_getdata() translates the data to native byte order.
+ */
+ note_data = elf_getdata(curr_section, NULL);
+ if (!note_data) {
+ goto error;
+ }
+
+ /* Check if the note is of the build-id type. */
+ is_build_id = is_build_id_note_section(note_data);
+ if (!is_build_id) {
+ continue;
+ }
+
+ /*
+ * Compare the build id of the on-disk file and
+ * the build id recorded in the trace.
+ */
+ is_matching = is_build_id_note_section_matching(
+ note_data, bin->build_id, bin->build_id_len);
+ if (!is_matching) {
+ break;
+ }
+ }
+error:
+ return is_matching;
+}
+
+BT_HIDDEN
+int bin_info_set_build_id(struct bin_info *bin, uint8_t *build_id,
+ size_t build_id_len)
+{
+ if (!bin || !build_id) {
+ goto error;
+ }
+
+ /* Set the build id. */
+ bin->build_id = g_new0(uint8_t, build_id_len);
+ if (!bin->build_id) {
+ goto error;
+ }
+
+ memcpy(bin->build_id, build_id, build_id_len);
+ bin->build_id_len = build_id_len;
+
+ /*
+ * Check if the file found on the file system has the same build id
+ * that what was recorded in the trace.
+ */
+ bin->file_build_id_matches = is_build_id_matching(bin);
+ if (!bin->file_build_id_matches) {
+ BT_LOGD_STR("Supplied Build ID does not match Build ID of the "
+ "binary or library found on the file system.");
+ goto error;
+ }
+
+ /*
+ * Reset the is_elf_only flag in case it had been set
+ * previously, because we might find separate debug info using
+ * the new build id information.
+ */
+ bin->is_elf_only = false;
+
+ return 0;
+
+error:
+ return -1;
+}
+
+BT_HIDDEN
+int bin_info_set_debug_link(struct bin_info *bin, const char *filename,
+ uint32_t crc)
+{
+ if (!bin || !filename) {
+ goto error;
+ }
+
+ bin->dbg_link_filename = g_strdup(filename);
+ if (!bin->dbg_link_filename) {
+ goto error;
+ }
+
+ bin->dbg_link_crc = crc;
+
+ /*
+ * Reset the is_elf_only flag in case it had been set
+ * previously, because we might find separate debug info using
+ * the new build id information.
+ */
+ bin->is_elf_only = false;
+
+ return 0;
+
+error:
+
+ return -1;
+}
+
+/**
+ * Tries to read DWARF info from the location given by path, and
+ * attach it to the given bin_info instance if it exists.
+ *
+ * @param bin bin_info instance for which to set DWARF info
+ * @param path Presumed location of the DWARF info
+ * @returns 0 on success, negative value on failure
+ */
+static
+int bin_info_set_dwarf_info_from_path(struct bin_info *bin, char *path)
+{
+ int ret = 0;
+ struct bt_fd_cache_handle *dwarf_handle = NULL;
+ struct bt_dwarf_cu *cu = NULL;
+ Dwarf *dwarf_info = NULL;
+
+ if (!bin || !path) {
+ goto error;
+ }
+
+ dwarf_handle = bt_fd_cache_get_handle(bin->fd_cache, path);
+ if (!dwarf_handle) {
+ goto error;
+ }
+
+ dwarf_info = dwarf_begin(bt_fd_cache_handle_get_fd(dwarf_handle),
+ DWARF_C_READ);
+ if (!dwarf_info) {
+ goto error;
+ }
+
+ /*
+ * Check if the dwarf info has any CU. If not, the
+ * executable's object file contains no DWARF info.
+ */
+ cu = bt_dwarf_cu_create(dwarf_info);
+ if (!cu) {
+ goto error;
+ }
+
+ ret = bt_dwarf_cu_next(cu);
+ if (ret) {
+ goto error;
+ }
+
+ bin->dwarf_handle = dwarf_handle;
+ bin->dwarf_path = g_strdup(path);
+ if (!bin->dwarf_path) {
+ goto error;
+ }
+ bin->dwarf_info = dwarf_info;
+ free(cu);
+
+ return 0;
+
+error:
+ bt_fd_cache_put_handle(bin->fd_cache, dwarf_handle);
+ dwarf_end(dwarf_info);
+ g_free(dwarf_info);
+ free(cu);
+
+ return -1;
+}
+
+/**
+ * Try to set the dwarf_info for a given bin_info instance via the
+ * build ID method.
+ *
+ * @param bin bin_info instance for which to retrieve the
+ * DWARF info via build ID
+ * @returns 0 on success (i.e. dwarf_info set), -1 on failure
+ */
+static
+int bin_info_set_dwarf_info_build_id(struct bin_info *bin)
+{
+ int i = 0, ret = 0;
+ char *path = NULL, *build_id_prefix_dir = NULL, *build_id_file = NULL;
+ const char *dbg_dir = NULL;
+ size_t build_id_char_len, build_id_suffix_char_len, build_id_file_len;
+
+ if (!bin || !bin->build_id) {
+ goto error;
+ }
+
+ dbg_dir = bin->debug_info_dir ? bin->debug_info_dir : DEFAULT_DEBUG_DIR;
+
+ /*
+ * The prefix dir is the first byte of the build id, represented in
+ * lowercase hex as two characters per byte, +1 for '\0'.
+ */
+ build_id_prefix_dir = g_new0(gchar, BUILD_ID_PREFIX_DIR_LEN + 1);
+ if (!build_id_prefix_dir) {
+ goto error;
+ }
+ g_snprintf(build_id_prefix_dir, BUILD_ID_PREFIX_DIR_LEN + 1, "%02x", bin->build_id[0]);
+
+ /*
+ * The build id file is the remaining bytes of the build id,
+ * represented in lowercase hex, as two characters per byte.
+ */
+ build_id_char_len = (2 * (bin->build_id_len - 1));
+
+ /* To which the build id suffix is added, +1 for '\0'. */
+ build_id_suffix_char_len = strlen(BUILD_ID_SUFFIX) + 1;
+
+ /*
+ * The resulting filename string is the concatenation of the
+ * hex build id and the suffix.
+ */
+ build_id_file_len = build_id_char_len + build_id_suffix_char_len;
+ build_id_file = g_new0(gchar, build_id_file_len);
+ if (!build_id_file) {
+ goto error;
+ }
+
+ /*
+ * For each byte, starting at offset 1, append two characters
+ * in lowercase hex.
+ */
+ for (i = 1; i < bin->build_id_len; ++i) {
+ int path_idx = 2 * (i - 1);
+
+ g_snprintf(&build_id_file[path_idx], 3, "%02x", bin->build_id[i]);
+ }
+ /* Append the suffix to the generated string, including the '\0'. */
+ g_snprintf(&build_id_file[build_id_char_len], build_id_suffix_char_len,
+ BUILD_ID_SUFFIX);
+
+ path = g_build_filename(dbg_dir, BUILD_ID_SUBDIR, build_id_prefix_dir, build_id_file, NULL);
+ if (!path) {
+ goto error;
+ }
+
+ ret = bin_info_set_dwarf_info_from_path(bin, path);
+ if (ret) {
+ goto error;
+ }
+
+ goto end;
+
+error:
+ ret = -1;
+end:
+ g_free(build_id_prefix_dir);
+ g_free(build_id_file);
+ g_free(path);
+
+ return ret;
+}
+
+/**
+ * Tests whether the file located at path exists and has the expected
+ * checksum.
+ *
+ * This predicate is used when looking up separate debug info via the
+ * GNU debuglink method. The expected crc can be found .gnu_debuglink
+ * section in the original ELF file, along with the filename for the
+ * file containing the debug info.
+ *
+ * @param path Full path at which to look for the debug file
+ * @param crc Expected checksum for the debug file
+ * @returns 1 if the file exists and has the correct checksum,
+ * 0 otherwise
+ */
+static
+int is_valid_debug_file(struct bin_info *bin, char *path, uint32_t crc)
+{
+ int ret = 0;
+ struct bt_fd_cache_handle *debug_handle = NULL;
+ uint32_t _crc = 0;
+
+ if (!path) {
+ goto end;
+ }
+
+ debug_handle = bt_fd_cache_get_handle(bin->fd_cache, path);
+ if (!debug_handle) {
+ goto end;
+ }
+
+ ret = crc32(bt_fd_cache_handle_get_fd(debug_handle), &_crc);
+ if (ret) {
+ ret = 0;
+ goto end;
+ }
+
+ ret = (crc == _crc);
+
+end:
+ bt_fd_cache_put_handle(bin->fd_cache, debug_handle);
+ return ret;
+}
+
+/**
+ * Try to set the dwarf_info for a given bin_info instance via the
+ * debug-link method.
+ *
+ * @param bin bin_info instance for which to retrieve the
+ * DWARF info via debug link
+ * @returns 0 on success (i.e. dwarf_info set), -1 on failure
+ */
+static
+int bin_info_set_dwarf_info_debug_link(struct bin_info *bin)
+{
+ int ret = 0;
+ const gchar *dbg_dir = NULL;
+ gchar *bin_dir = NULL, *path = NULL;
+
+ if (!bin || !bin->dbg_link_filename) {
+ goto error;
+ }
+
+ dbg_dir = bin->debug_info_dir ? bin->debug_info_dir : DEFAULT_DEBUG_DIR;
+ bin_dir = g_path_get_dirname(bin->elf_path);
+
+ /* First look in the executable's dir */
+ path = g_build_filename(bin_dir, bin->dbg_link_filename, NULL);
+
+ if (is_valid_debug_file(bin, path, bin->dbg_link_crc)) {
+ goto found;
+ }
+
+ /* If not found, look in .debug subdir */
+ g_free(path);
+ path = g_build_filename(bin_dir, DEBUG_SUBDIR, bin->dbg_link_filename, NULL);
+
+ if (is_valid_debug_file(bin, path, bin->dbg_link_crc)) {
+ goto found;
+ }
+
+ /* Lastly, look under the global debug directory */
+ g_free(path);
+
+ path = g_build_filename(dbg_dir, bin_dir, bin->dbg_link_filename, NULL);
+ if (is_valid_debug_file(bin, path, bin->dbg_link_crc)) {
+ goto found;
+ }
+
+error:
+ ret = -1;
+end:
+ g_free(bin_dir);
+ g_free(path);
+
+ return ret;
+
+found:
+ ret = bin_info_set_dwarf_info_from_path(bin, path);
+ if (ret) {
+ goto error;
+ }
+
+ goto end;
+}
+
+/**
+ * Initialize the DWARF info for a given executable.
+ *
+ * @param bin bin_info instance
+ * @returns 0 on success, negative value on failure
+ */
+static
+int bin_info_set_dwarf_info(struct bin_info *bin)
+{
+ int ret = 0;
+
+ if (!bin) {
+ ret = -1;
+ goto end;
+ }
+
+ /* First try to set the DWARF info from the ELF file */
+ ret = bin_info_set_dwarf_info_from_path(bin, bin->elf_path);
+ if (!ret) {
+ goto end;
+ }
+
+ /*
+ * If that fails, try to find separate debug info via build ID
+ * and debug link.
+ */
+ ret = bin_info_set_dwarf_info_build_id(bin);
+ if (!ret) {
+ goto end;
+ }
+
+ ret = bin_info_set_dwarf_info_debug_link(bin);
+ if (!ret) {
+ goto end;
+ }
+
+end:
+ return ret;
+}
+
+BT_HIDDEN
+void source_location_destroy(struct source_location *src_loc)
+{
+ if (!src_loc) {
+ return;
+ }
+
+ free(src_loc->filename);
+ g_free(src_loc);
+}
+
+/**
+ * Append a string representation of an address offset to an existing
+ * string.
+ *
+ * On success, the out parameter `result` will contain the base string
+ * followed by the offset string of the form "+0x1234". On failure,
+ * `result` remains unchanged.
+ *
+ * @param base_str The string to which to append an offset string
+ * @param low_addr The lower virtual memory address, the base from
+ * which the offset is computed
+ * @param high_addr The higher virtual memory address
+ * @param result Out parameter, the base string followed by the
+ * offset string
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_append_offset_str(const char *base_str, uint64_t low_addr,
+ uint64_t high_addr, char **result)
+{
+ uint64_t offset;
+ char *_result = NULL;
+
+ if (!base_str || !result) {
+ goto error;
+ }
+
+ offset = high_addr - low_addr;
+
+ _result = g_strdup_printf("%s+%#0" PRIx64, base_str, offset);
+ if (!_result) {
+ goto error;
+ }
+ *result = _result;
+
+ return 0;
+
+error:
+ free(_result);
+ return -1;
+}
+
+/**
+ * Try to find the symbol closest to an address within a given ELF
+ * section.
+ *
+ * Only function symbols are taken into account. The symbol's address
+ * must precede `addr`. A symbol with a closer address might exist
+ * after `addr` but is irrelevant because it cannot encompass `addr`.
+ *
+ * On success, if found, the out parameters `sym` and `shdr` are
+ * set. On failure or if none are found, they remain unchanged.
+ *
+ * @param scn ELF section in which to look for the address
+ * @param addr Virtual memory address for which to find the
+ * nearest function symbol
+ * @param sym Out parameter, the nearest function symbol
+ * @param shdr Out parameter, the section header for scn
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_get_nearest_symbol_from_section(Elf_Scn *scn, uint64_t addr,
+ GElf_Sym **sym, GElf_Shdr **shdr)
+{
+ int i;
+ size_t symbol_count;
+ Elf_Data *data = NULL;
+ GElf_Shdr *_shdr = NULL;
+ GElf_Sym *nearest_sym = NULL;
+
+ if (!scn || !sym || !shdr) {
+ goto error;
+ }
+
+ _shdr = g_new0(GElf_Shdr, 1);
+ if (!_shdr) {
+ goto error;
+ }
+
+ _shdr = gelf_getshdr(scn, _shdr);
+ if (!_shdr) {
+ goto error;
+ }
+
+ if (_shdr->sh_type != SHT_SYMTAB) {
+ /*
+ * We are only interested in symbol table (symtab)
+ * sections, skip this one.
+ */
+ goto end;
+ }
+
+ data = elf_getdata(scn, NULL);
+ if (!data) {
+ goto error;
+ }
+
+ symbol_count = _shdr->sh_size / _shdr->sh_entsize;
+
+ for (i = 0; i < symbol_count; ++i) {
+ GElf_Sym *cur_sym = NULL;
+
+ cur_sym = g_new0(GElf_Sym, 1);
+ if (!cur_sym) {
+ goto error;
+ }
+ cur_sym = gelf_getsym(data, i, cur_sym);
+ if (!cur_sym) {
+ goto error;
+ }
+ if (GELF_ST_TYPE(cur_sym->st_info) != STT_FUNC) {
+ /* We're only interested in the functions. */
+ g_free(cur_sym);
+ continue;
+ }
+
+ if (cur_sym->st_value <= addr &&
+ (!nearest_sym ||
+ cur_sym->st_value > nearest_sym->st_value)) {
+ g_free(nearest_sym);
+ nearest_sym = cur_sym;
+ } else {
+ g_free(cur_sym);
+ }
+ }
+
+end:
+ if (nearest_sym) {
+ *sym = nearest_sym;
+ *shdr = _shdr;
+ } else {
+ g_free(_shdr);
+ }
+
+ return 0;
+
+error:
+ g_free(nearest_sym);
+ g_free(_shdr);
+ return -1;
+}
+
+/**
+ * Get the name of the function containing a given address within an
+ * executable using ELF symbols.
+ *
+ * The function name is in fact the name of the nearest ELF symbol,
+ * followed by the offset in bytes between the address and the symbol
+ * (in hex), separated by a '+' character.
+ *
+ * If found, the out parameter `func_name` is set on success. On failure,
+ * it remains unchanged.
+ *
+ * @param bin bin_info instance for the executable containing
+ * the address
+ * @param addr Virtual memory address for which to find the
+ * function name
+ * @param func_name Out parameter, the function name
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_lookup_elf_function_name(struct bin_info *bin, uint64_t addr,
+ char **func_name)
+{
+ /*
+ * TODO (possible optimisation): if an ELF has no symtab
+ * section, it has been stripped. Therefore, it would be wise
+ * to store a flag indicating the stripped status after the
+ * first iteration to prevent subsequent ones.
+ */
+ int ret = 0;
+ Elf_Scn *scn = NULL;
+ GElf_Sym *sym = NULL;
+ GElf_Shdr *shdr = NULL;
+ char *sym_name = NULL;
+
+ /* Set ELF file if it hasn't been accessed yet. */
+ if (!bin->elf_file) {
+ ret = bin_info_set_elf_file(bin);
+ if (ret) {
+ /* Failed to set ELF file. */
+ goto error;
+ }
+ }
+
+ scn = elf_nextscn(bin->elf_file, scn);
+ if (!scn) {
+ goto error;
+ }
+
+ while (scn && !sym) {
+ ret = bin_info_get_nearest_symbol_from_section(
+ scn, addr, &sym, &shdr);
+ if (ret) {
+ goto error;
+ }
+
+ scn = elf_nextscn(bin->elf_file, scn);
+ }
+
+ if (sym) {
+ sym_name = elf_strptr(bin->elf_file, shdr->sh_link,
+ sym->st_name);
+ if (!sym_name) {
+ goto error;
+ }
+
+ ret = bin_info_append_offset_str(sym_name, sym->st_value, addr,
+ func_name);
+ if (ret) {
+ goto error;
+ }
+ }
+
+ g_free(shdr);
+ g_free(sym);
+ return 0;
+
+error:
+ g_free(shdr);
+ g_free(sym);
+ return ret;
+}
+
+/**
+ * Get the name of the function containing a given address within a
+ * given compile unit (CU).
+ *
+ * If found, the out parameter `func_name` is set on success. On
+ * failure, it remains unchanged.
+ *
+ * @param cu bt_dwarf_cu instance which may contain the address
+ * @param addr Virtual memory address for which to find the
+ * function name
+ * @param func_name Out parameter, the function name
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
+ char **func_name)
+{
+ int ret = 0;
+ bool found = false;
+ struct bt_dwarf_die *die = NULL;
+
+ if (!cu || !func_name) {
+ goto error;
+ }
+
+ die = bt_dwarf_die_create(cu);
+ if (!die) {
+ goto error;
+ }
+
+ while (bt_dwarf_die_next(die) == 0) {
+ int tag;
+
+ ret = bt_dwarf_die_get_tag(die, &tag);
+ if (ret) {
+ goto error;
+ }
+
+ if (tag == DW_TAG_subprogram) {
+ ret = bt_dwarf_die_contains_addr(die, addr, &found);
+ if (ret) {
+ goto error;
+ }
+
+ if (found) {
+ break;
+ }
+ }
+ }
+
+ if (found) {
+ uint64_t low_addr = 0;
+ char *die_name = NULL;
+
+ ret = bt_dwarf_die_get_name(die, &die_name);
+ if (ret) {
+ goto error;
+ }
+
+ ret = dwarf_lowpc(die->dwarf_die, &low_addr);
+ if (ret) {
+ free(die_name);
+ goto error;
+ }
+
+ ret = bin_info_append_offset_str(die_name, low_addr, addr,
+ func_name);
+ free(die_name);
+ if (ret) {
+ goto error;
+ }
+ }
+
+ bt_dwarf_die_destroy(die);
+ return 0;
+
+error:
+ bt_dwarf_die_destroy(die);
+ return -1;
+}
+
+/**
+ * Get the name of the function containing a given address within an
+ * executable using DWARF debug info.
+ *
+ * If found, the out parameter `func_name` is set on success. On
+ * failure, it remains unchanged.
+ *
+ * @param bin bin_info instance for the executable containing
+ * the address
+ * @param addr Virtual memory address for which to find the
+ * function name
+ * @param func_name Out parameter, the function name
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_lookup_dwarf_function_name(struct bin_info *bin, uint64_t addr,
+ char **func_name)
+{
+ int ret = 0;
+ char *_func_name = NULL;
+ struct bt_dwarf_cu *cu = NULL;
+
+ if (!bin || !func_name) {
+ goto error;
+ }
+
+ cu = bt_dwarf_cu_create(bin->dwarf_info);
+ if (!cu) {
+ goto error;
+ }
+
+ while (bt_dwarf_cu_next(cu) == 0) {
+ ret = bin_info_lookup_cu_function_name(cu, addr, &_func_name);
+ if (ret) {
+ goto error;
+ }
+
+ if (_func_name) {
+ break;
+ }
+ }
+
+ if (_func_name) {
+ *func_name = _func_name;
+ } else {
+ goto error;
+ }
+
+ bt_dwarf_cu_destroy(cu);
+ return 0;
+
+error:
+ bt_dwarf_cu_destroy(cu);
+ return -1;
+}
+
+BT_HIDDEN
+int bin_info_lookup_function_name(struct bin_info *bin,
+ uint64_t addr, char **func_name)
+{
+ int ret = 0;
+ char *_func_name = NULL;
+
+ if (!bin || !func_name) {
+ goto error;
+ }
+
+ /*
+ * If the bin_info has a build id but it does not match the build id
+ * that was found on the file system, return an error.
+ */
+ if (bin->build_id && !bin->file_build_id_matches) {
+ goto error;
+ }
+
+ /* Set DWARF info if it hasn't been accessed yet. */
+ if (!bin->dwarf_info && !bin->is_elf_only) {
+ ret = bin_info_set_dwarf_info(bin);
+ if (ret) {
+ BT_LOGD_STR("Failed to set bin dwarf info, falling "
+ "back to ELF lookup.");
+ /* Failed to set DWARF info, fallback to ELF. */
+ bin->is_elf_only = true;
+ }
+ }
+
+ if (!bin_info_has_address(bin, addr)) {
+ goto error;
+ }
+
+ /*
+ * Addresses in ELF and DWARF are relative to base address for
+ * PIC, so make the address argument relative too if needed.
+ */
+ if (bin->is_pic) {
+ addr -= bin->low_addr;
+ }
+
+ if (bin->is_elf_only) {
+ ret = bin_info_lookup_elf_function_name(bin, addr,
+ &_func_name);
+ if (ret) {
+ BT_LOGD("Failed to lookup function name (ELF): "
+ "ret=%d", ret);
+ }
+ } else {
+ ret = bin_info_lookup_dwarf_function_name(bin, addr,
+ &_func_name);
+ if (ret) {
+ BT_LOGD("Failed to lookup function name (DWARF): "
+ "ret=%d", ret);
+ }
+ }
+
+ *func_name = _func_name;
+ return 0;
+
+error:
+ return -1;
+}
+
+BT_HIDDEN
+int bin_info_get_bin_loc(struct bin_info *bin, uint64_t addr, char **bin_loc)
+{
+ gchar *_bin_loc = NULL;
+
+ if (!bin || !bin_loc) {
+ goto error;
+ }
+
+ /*
+ * If the bin_info has a build id but it does not match the build id
+ * that was found on the file system, return an error.
+ */
+ if (bin->build_id && !bin->file_build_id_matches) {
+ goto error;
+ }
+
+ if (bin->is_pic) {
+ addr -= bin->low_addr;
+ _bin_loc = g_strdup_printf("+%#0" PRIx64, addr);
+ } else {
+ _bin_loc = g_strdup_printf("@%#0" PRIx64, addr);
+ }
+
+ if (!_bin_loc) {
+ goto error;
+ }
+
+ *bin_loc = _bin_loc;
+ return 0;
+
+error:
+ return -1;
+}
+
+/**
+ * Predicate used to determine whether the children of a given DIE
+ * contain a specific address.
+ *
+ * More specifically, the parameter `die` is expected to be a
+ * subprogram (function) DIE, and this predicate tells whether any
+ * subroutines are inlined within this function and would contain
+ * `addr`.
+ *
+ * On success, the out parameter `contains` is set with the boolean
+ * value indicating whether the DIE's range covers `addr`. On failure,
+ * it remains unchanged.
+ *
+ * Do note that this function advances the position of `die`. If the
+ * address is found within one of its children, `die` will be pointing
+ * to that child upon returning from the function, allowing to extract
+ * the information deemed necessary.
+ *
+ * @param die The parent DIE in whose children the address will be
+ * looked for
+ * @param addr The address for which to look for in the DIEs
+ * @param contains Out parameter, true if addr is contained,
+ * false if not
+ * @returns Returns 0 on success, -1 on failure
+ */
+static
+int bin_info_child_die_has_address(struct bt_dwarf_die *die, uint64_t addr, bool *contains)
+{
+ int ret = 0;
+ bool _contains = false;
+
+ if (!die) {
+ goto error;
+ }
+
+ ret = bt_dwarf_die_child(die);
+ if (ret) {
+ goto error;
+ }
+
+ do {
+ ret = bt_dwarf_die_contains_addr(die, addr, &_contains);
+ if (ret) {
+ goto error;
+ }
+
+ if (_contains) {
+ /*
+ * The address is within the range of the current DIE
+ * or its children.
+ */
+ int tag;
+
+ ret = bt_dwarf_die_get_tag(die, &tag);
+ if (ret) {
+ goto error;
+ }
+
+ if (tag == DW_TAG_inlined_subroutine) {
+ /* Found the tracepoint. */
+ goto end;
+ }
+
+ if (bt_dwarf_die_has_children(die)) {
+ /*
+ * Look for the address in the children DIEs.
+ */
+ ret = bt_dwarf_die_child(die);
+ if (ret) {
+ goto error;
+ }
+ }
+ }
+ } while (bt_dwarf_die_next(die) == 0);
+
+end:
+ *contains = _contains;
+ return 0;
+
+error:
+ return -1;
+}
+
+/**
+ * Lookup the source location for a given address within a CU, making
+ * the assumption that it is contained within an inline routine in a
+ * function.
+ *
+ * @param cu bt_dwarf_cu instance in which to look for the address
+ * @param addr The address for which to look for
+ * @param src_loc Out parameter, the source location (filename and
+ * line number) for the address
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_lookup_cu_src_loc_inl(struct bt_dwarf_cu *cu, uint64_t addr,
+ struct source_location **src_loc)
+{
+ int ret = 0;
+ bool found = false;
+ struct bt_dwarf_die *die = NULL;
+ struct source_location *_src_loc = NULL;
+
+ if (!cu || !src_loc) {
+ goto error;
+ }
+
+ die = bt_dwarf_die_create(cu);
+ if (!die) {
+ goto error;
+ }
+
+ while (bt_dwarf_die_next(die) == 0) {
+ int tag;
+
+ ret = bt_dwarf_die_get_tag(die, &tag);
+ if (ret) {
+ goto error;
+ }
+
+ if (tag == DW_TAG_subprogram) {
+ bool contains = false;
+
+ ret = bt_dwarf_die_contains_addr(die, addr, &contains);
+ if (ret) {
+ goto error;
+ }
+
+ if (contains) {
+ /*
+ * Try to find an inlined subroutine
+ * child of this DIE containing addr.
+ */
+ ret = bin_info_child_die_has_address(die, addr,
+ &found);
+ if(ret) {
+ goto error;
+ }
+
+ goto end;
+ }
+ }
+ }
+
+end:
+ if (found) {
+ char *filename = NULL;
+ uint64_t line_no;
+
+ _src_loc = g_new0(struct source_location, 1);
+ if (!_src_loc) {
+ goto error;
+ }
+
+ ret = bt_dwarf_die_get_call_file(die, &filename);
+ if (ret) {
+ goto error;
+ }
+ ret = bt_dwarf_die_get_call_line(die, &line_no);
+ if (ret) {
+ free(filename);
+ goto error;
+ }
+
+ _src_loc->filename = filename;
+ _src_loc->line_no = line_no;
+ *src_loc = _src_loc;
+ }
+
+ bt_dwarf_die_destroy(die);
+ return 0;
+
+error:
+ source_location_destroy(_src_loc);
+ bt_dwarf_die_destroy(die);
+ return -1;
+}
+
+/**
+ * Lookup the source location for a given address within a CU,
+ * assuming that it is contained within an inlined function.
+ *
+ * A source location can be found regardless of inlining status for
+ * this method, but in the case of an inlined function, the returned
+ * source location will point not to the callsite but rather to the
+ * definition site of the inline function.
+ *
+ * @param cu bt_dwarf_cu instance in which to look for the address
+ * @param addr The address for which to look for
+ * @param src_loc Out parameter, the source location (filename and
+ * line number) for the address. Set only if the address
+ * is found and resolved successfully
+ *
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_lookup_cu_src_loc_no_inl(struct bt_dwarf_cu *cu, uint64_t addr,
+ struct source_location **src_loc)
+{
+ struct source_location *_src_loc = NULL;
+ struct bt_dwarf_die *die = NULL;
+ const char *filename = NULL;
+ Dwarf_Line *line = NULL;
+ Dwarf_Addr line_addr;
+ int ret = 0, line_no;
+
+ if (!cu || !src_loc) {
+ goto error;
+ }
+
+ die = bt_dwarf_die_create(cu);
+ if (!die) {
+ goto error;
+ }
+
+ line = dwarf_getsrc_die(die->dwarf_die, addr);
+ if (!line) {
+ /* This is not an error. The caller needs to keep looking. */
+ goto end;
+ }
+
+ ret = dwarf_lineaddr(line, &line_addr);
+ if (ret) {
+ goto error;
+ }
+
+ filename = dwarf_linesrc(line, NULL, NULL);
+ if (!filename) {
+ goto error;
+ }
+
+ if (addr == line_addr) {
+ _src_loc = g_new0(struct source_location, 1);
+ if (!_src_loc) {
+ goto error;
+ }
+
+ ret = dwarf_lineno(line, &line_no);
+ if (ret) {
+ goto error;
+ }
+
+ _src_loc->line_no = line_no;
+ _src_loc->filename = g_strdup(filename);
+ }
+
+ if (_src_loc) {
+ *src_loc = _src_loc;
+ }
+
+ goto end;
+
+error:
+ source_location_destroy(_src_loc);
+ ret = -1;
+end:
+ bt_dwarf_die_destroy(die);
+ return ret;
+}
+
+/**
+ * Get the source location (file name and line number) for a given
+ * address within a compile unit (CU).
+ *
+ * On success, the out parameter `src_loc` is set if found. On
+ * failure, it remains unchanged.
+ *
+ * @param cu bt_dwarf_cu instance for the compile unit which
+ * may contain the address
+ * @param addr Virtual memory address for which to find the
+ * source location
+ * @param src_loc Out parameter, the source location
+ * @returns 0 on success, -1 on failure
+ */
+static
+int bin_info_lookup_cu_src_loc(struct bt_dwarf_cu *cu, uint64_t addr,
+ struct source_location **src_loc)
+{
+ int ret = 0;
+ struct source_location *_src_loc = NULL;
+
+ if (!cu || !src_loc) {
+ goto error;
+ }
+
+ ret = bin_info_lookup_cu_src_loc_inl(cu, addr, &_src_loc);
+ if (ret) {
+ goto error;
+ }
+
+ if (_src_loc) {
+ goto end;
+ }
+
+ ret = bin_info_lookup_cu_src_loc_no_inl(cu, addr, &_src_loc);
+ if (ret) {
+ goto error;
+ }
+
+ if (_src_loc) {
+ goto end;
+ }
+
+end:
+ if (_src_loc) {
+ *src_loc = _src_loc;
+ }
+
+ return 0;
+
+error:
+ source_location_destroy(_src_loc);
+ return -1;
+}
+
+BT_HIDDEN
+int bin_info_lookup_source_location(struct bin_info *bin, uint64_t addr,
+ struct source_location **src_loc)
+{
+ struct bt_dwarf_cu *cu = NULL;
+ struct source_location *_src_loc = NULL;
+
+ if (!bin || !src_loc) {
+ goto error;
+ }
+
+ /*
+ * If the bin_info has a build id but it does not match the build id
+ * that was found on the file system, return an error.
+ */
+ if (bin->build_id && !bin->file_build_id_matches) {
+ goto error;
+ }
+
+ /* Set DWARF info if it hasn't been accessed yet. */
+ if (!bin->dwarf_info && !bin->is_elf_only) {
+ if (bin_info_set_dwarf_info(bin)) {
+ /* Failed to set DWARF info. */
+ bin->is_elf_only = true;
+ }
+ }
+
+ if (bin->is_elf_only) {
+ /* We cannot lookup source location without DWARF info. */
+ goto error;
+ }
+
+ if (!bin_info_has_address(bin, addr)) {
+ goto error;
+ }
+
+ /*
+ * Addresses in ELF and DWARF are relative to base address for
+ * PIC, so make the address argument relative too if needed.
+ */
+ if (bin->is_pic) {
+ addr -= bin->low_addr;
+ }
+
+ cu = bt_dwarf_cu_create(bin->dwarf_info);
+ if (!cu) {
+ goto error;
+ }
+
+ while (bt_dwarf_cu_next(cu) == 0) {
+ int ret;
+
+ ret = bin_info_lookup_cu_src_loc(cu, addr, &_src_loc);
+ if (ret) {
+ goto error;
+ }
+
+ if (_src_loc) {
+ break;
+ }
+ }
+
+ bt_dwarf_cu_destroy(cu);
+ if (_src_loc) {
+ *src_loc = _src_loc;
+ }
+
+ return 0;
+
+error:
+ source_location_destroy(_src_loc);
+ bt_dwarf_cu_destroy(cu);
+ return -1;
+}
projects / babeltrace.git / blobdiff