+/*
+ * so-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.
+ */
+
+#include <fcntl.h>
+#include <math.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <dwarf.h>
+#include <glib.h>
+#include <babeltrace/dwarf.h>
+#include <babeltrace/so-info.h>
+#include <babeltrace/crc32.h>
+#include <babeltrace/babeltrace-internal.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
+
+BT_HIDDEN
+int so_info_init(void)
+{
+ int ret = 0;
+
+ if (elf_version(EV_CURRENT) == EV_NONE) {
+ fprintf(stderr, "ELF library initialization failed: %s\n",
+ elf_errmsg(-1));
+ ret = -1;
+ }
+
+ return ret;
+}
+
+BT_HIDDEN
+struct so_info *so_info_create(const char *path, uint64_t low_addr,
+ uint64_t memsz)
+{
+ struct so_info *so = NULL;
+ GElf_Ehdr *ehdr = NULL;
+
+ if (!path) {
+ goto error;
+ }
+
+ so = g_new0(struct so_info, 1);
+ if (!so) {
+ goto error;
+ }
+
+ so->elf_path = strdup(path);
+ if (!so->elf_path) {
+ goto error;
+ }
+
+ so->elf_fd = open(path, O_RDONLY);
+ if (so->elf_fd < 0) {
+ fprintf(stderr, "Failed to open %s\n", path);
+ goto error;
+ }
+
+ so->elf_file = elf_begin(so->elf_fd, ELF_C_READ, NULL);
+ if (!so->elf_file) {
+ fprintf(stderr, "elf_begin failed: %s\n", elf_errmsg(-1));
+ goto error;
+ }
+
+ if (elf_kind(so->elf_file) != ELF_K_ELF) {
+ fprintf(stderr, "Error: %s is not an ELF object\n",
+ so->elf_path);
+ goto error;
+ }
+
+ ehdr = g_new0(GElf_Ehdr, 1);
+ if (!ehdr) {
+ goto error;
+ }
+
+ if (!gelf_getehdr(so->elf_file, ehdr)) {
+ fprintf(stderr, "Error: couldn't get ehdr for %s\n",
+ so->elf_path);
+ goto error;
+ }
+
+ /* Position independent code has an e_type value of ET_DYN. */
+ so->is_pic = ehdr->e_type == ET_DYN;
+ so->memsz = memsz;
+ so->low_addr = low_addr;
+ so->high_addr = so->low_addr + so->memsz;
+
+ g_free(ehdr);
+ return so;
+
+error:
+ g_free(ehdr);
+ so_info_destroy(so);
+ return NULL;
+}
+
+BT_HIDDEN
+void so_info_destroy(struct so_info *so)
+{
+ if (!so) {
+ return;
+ }
+
+ dwarf_end(so->dwarf_info);
+
+ free(so->elf_path);
+ free(so->dwarf_path);
+ free(so->build_id);
+ free(so->dbg_link_filename);
+
+ elf_end(so->elf_file);
+
+ close(so->elf_fd);
+ close(so->dwarf_fd);
+
+ g_free(so);
+}
+
+BT_HIDDEN
+int so_info_set_build_id(struct so_info *so, uint8_t *build_id,
+ size_t build_id_len)
+{
+ if (!so || !build_id) {
+ goto error;
+ }
+
+ so->build_id = malloc(build_id_len);
+ if (!so->build_id) {
+ goto error;
+ }
+
+ memcpy(so->build_id, build_id, build_id_len);
+ so->build_id_len = build_id_len;
+
+ /*
+ * 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.
+ */
+ so->is_elf_only = false;
+
+ return 0;
+
+error:
+
+ return -1;
+}
+
+BT_HIDDEN
+int so_info_set_debug_link(struct so_info *so, char *filename, uint32_t crc)
+{
+ if (!so || !filename) {
+ goto error;
+ }
+
+ so->dbg_link_filename = strdup(filename);
+ if (!so->dbg_link_filename) {
+ goto error;
+ }
+
+ so->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.
+ */
+ so->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 so_info instance if it exists.
+ *
+ * @param so so_info instance for which to set DWARF info
+ * @param path Presumed location of the DWARF info
+ * @returns 0 on success, -1 on failure
+ */
+static
+int so_info_set_dwarf_info_from_path(struct so_info *so, char *path)
+{
+ int fd = -1, ret = 0;
+ struct bt_dwarf_cu *cu = NULL;
+ Dwarf *dwarf_info = NULL;
+
+ if (!so || !path) {
+ goto error;
+ }
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ goto error;
+ }
+
+ dwarf_info = dwarf_begin(fd, DWARF_C_READ);
+ if (!dwarf_info) {
+ goto error;
+ }
+
+ /*
+ * Check if the dwarf info has any CU. If not, the SO'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;
+ }
+
+ so->dwarf_fd = fd;
+ so->dwarf_path = strdup(path);
+ if (!so->dwarf_path) {
+ goto error;
+ }
+ so->dwarf_info = dwarf_info;
+ free(cu);
+
+ return 0;
+
+error:
+ close(fd);
+ dwarf_end(dwarf_info);
+ g_free(dwarf_info);
+ free(cu);
+
+ return -1;
+}
+
+/**
+ * Try to set the dwarf_info for a given so_info instance via the
+ * build ID method.
+ *
+ * @param so so_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 so_info_set_dwarf_info_build_id(struct so_info *so)
+{
+ int i = 0, ret = 0, dbg_dir_trailing_slash = 0;
+ char *path = NULL, *build_id_file = NULL;
+ const char *dbg_dir = NULL;
+ size_t build_id_file_len, path_len;
+
+ if (!so || !so->build_id) {
+ goto error;
+ }
+
+ dbg_dir = opt_debug_dir ? : DEFAULT_DEBUG_DIR;
+
+ dbg_dir_trailing_slash = dbg_dir[strlen(dbg_dir) - 1] == '/';
+
+ /* 2 characters per byte printed in hex, +2 for '/' and '\0' */
+ build_id_file_len = (2 * so->build_id_len) + 2;
+ build_id_file = malloc(build_id_file_len);
+ if (!build_id_file) {
+ goto error;
+ }
+
+ snprintf(build_id_file, 4, "%02x/", so->build_id[0]);
+ for (i = 1; i < so->build_id_len; ++i) {
+ int path_idx = 3 + 2 * (i - 1);
+
+ snprintf(&build_id_file[path_idx], 3, "%02x", so->build_id[i]);
+ }
+
+ path_len = strlen(dbg_dir) + strlen(BUILD_ID_SUBDIR) +
+ strlen(build_id_file) + strlen(BUILD_ID_SUFFIX) + 1;
+ if (!dbg_dir_trailing_slash) {
+ path_len += 1;
+ }
+
+ path = malloc(path_len);
+ if (!path) {
+ goto error;
+ }
+
+ strcpy(path, dbg_dir);
+ if (!dbg_dir_trailing_slash) {
+ strcat(path, "/");
+ }
+ strcat(path, BUILD_ID_SUBDIR);
+ strcat(path, build_id_file);
+ strcat(path, BUILD_ID_SUFFIX);
+
+ ret = so_info_set_dwarf_info_from_path(so, path);
+ if (ret) {
+ goto error;
+ }
+
+ goto end;
+
+error:
+ ret = -1;
+end:
+ free(build_id_file);
+ 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(char *path, uint32_t crc)
+{
+ int ret = 0, fd = -1;
+ uint32_t _crc = 0;
+
+ if (!path) {
+ goto end;
+ }
+
+ fd = open(path, O_RDONLY);
+ if (fd < 0) {
+ goto end;
+ }
+
+ ret = crc32(fd, &_crc);
+ if (ret) {
+ ret = 0;
+ goto end;
+ }
+
+ ret = (crc == _crc);
+
+end:
+ close(fd);
+ return ret;
+}
+
+/**
+ * Try to set the dwarf_info for a given so_info instance via the
+ * build ID method.
+ *
+ * @param so so_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 so_info_set_dwarf_info_debug_link(struct so_info *so)
+{
+ int ret = 0;
+ const char *dbg_dir = NULL;
+ char *dir_name = NULL, *so_dir = NULL, *path = NULL;
+ size_t max_path_len = 0;
+
+ if (!so || !so->dbg_link_filename) {
+ goto error;
+ }
+
+ dbg_dir = opt_debug_dir ? : DEFAULT_DEBUG_DIR;
+
+ dir_name = dirname(so->elf_path);
+ if (!dir_name) {
+ goto error;
+ }
+
+ /* so_dir is just dir_name with a trailing slash */
+ so_dir = malloc(strlen(dir_name) + 2);
+ if (!so_dir) {
+ goto error;
+ }
+
+ strcpy(so_dir, dir_name);
+ strcat(so_dir, "/");
+
+ max_path_len = strlen(dbg_dir) + strlen(so_dir) +
+ strlen(DEBUG_SUBDIR) + strlen(so->dbg_link_filename)
+ + 1;
+ path = malloc(max_path_len);
+ if (!path) {
+ goto error;
+ }
+
+ /* First look in the SO's dir */
+ strcpy(path, so_dir);
+ strcat(path, so->dbg_link_filename);
+
+ if (is_valid_debug_file(path, so->dbg_link_crc)) {
+ goto found;
+ }
+
+ /* If not found, look in .debug subdir */
+ strcpy(path, so_dir);
+ strcat(path, DEBUG_SUBDIR);
+ strcat(path, so->dbg_link_filename);
+
+ if (is_valid_debug_file(path, so->dbg_link_crc)) {
+ goto found;
+ }
+
+ /* Lastly, look under the global debug directory */
+ strcpy(path, dbg_dir);
+ strcat(path, so_dir);
+ strcat(path, so->dbg_link_filename);
+
+ if (is_valid_debug_file(path, so->dbg_link_crc)) {
+ goto found;
+ }
+
+error:
+ ret = -1;
+end:
+ free(path);
+ free(so_dir);
+
+ return ret;
+
+found:
+ ret = so_info_set_dwarf_info_from_path(so, path);
+ if (ret) {
+ goto error;
+ }
+
+ goto end;
+}
+
+/**
+ * Initialize the DWARF info for a given executable.
+ *
+ * @param so so_info instance
+ * @returns 0 on success, -1 on failure
+ */
+static
+int so_info_set_dwarf_info(struct so_info *so)
+{
+ int ret = 0;
+
+ if (!so) {
+ goto error;
+ }
+
+ /* First try to set the DWARF info from the ELF file */
+ ret = so_info_set_dwarf_info_from_path(so, so->elf_path);
+ if (!ret) {
+ goto end;
+ }
+
+ /*
+ * If that fails, try to find separate debug info via build ID
+ * and debug link.
+ */
+ ret = so_info_set_dwarf_info_build_id(so);
+ if (!ret) {
+ goto end;
+ }
+
+ ret = so_info_set_dwarf_info_debug_link(so);
+ if (!ret) {
+ goto end;
+ }
+
+error:
+ ret = -1;
+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);
+}
+
+/**
+ * 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 so_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 so so_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 so_info_lookup_elf_function_name(struct so_info *so, 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;
+ char *_func_name = NULL;
+ char offset_str[ADDR_STR_LEN];
+
+ scn = elf_nextscn(so->elf_file, scn);
+ if (!scn) {
+ goto error;
+ }
+
+ while (scn && !sym) {
+ ret = so_info_get_nearest_symbol_from_section(
+ scn, addr, &sym, &shdr);
+ if (ret) {
+ goto error;
+ }
+
+ scn = elf_nextscn(so->elf_file, scn);
+ }
+
+ if (sym) {
+ sym_name = elf_strptr(so->elf_file, shdr->sh_link,
+ sym->st_name);
+ if (!sym_name) {
+ goto error;
+ }
+
+ snprintf(offset_str, ADDR_STR_LEN, "+%#0" PRIx64,
+ addr - sym->st_value);
+ _func_name = malloc(strlen(sym_name) + ADDR_STR_LEN);
+ if (!_func_name) {
+ goto error;
+ }
+
+ strcpy(_func_name, sym_name);
+ strcat(_func_name, offset_str);
+ *func_name = _func_name;
+ }
+
+ g_free(shdr);
+ g_free(sym);
+ return 0;
+
+error:
+ g_free(shdr);
+ g_free(sym);
+ free(_func_name);
+ return -1;
+}
+
+/**
+ * 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 so_info_lookup_cu_function_name(struct bt_dwarf_cu *cu, uint64_t addr,
+ char **func_name)
+{
+ int ret = 0, found = 0;
+ char *_func_name = NULL;
+ 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) {
+ ret = bt_dwarf_die_get_name(die, &_func_name);
+ if (ret) {
+ goto error;
+ }
+
+ *func_name = _func_name;
+ }
+
+ 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 so so_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 so_info_lookup_dwarf_function_name(struct so_info *so, uint64_t addr,
+ char **func_name)
+{
+ int ret = 0;
+ char *_func_name = NULL;
+ struct bt_dwarf_cu *cu = NULL;
+
+ if (!so || !func_name) {
+ goto error;
+ }
+
+ cu = bt_dwarf_cu_create(so->dwarf_info);
+ if (!cu) {
+ goto error;
+ }
+
+ while (bt_dwarf_cu_next(cu) == 0) {
+ ret = so_info_lookup_cu_function_name(cu, addr, &_func_name);
+ if (ret) {
+ goto error;
+ }
+
+ if (_func_name) {
+ break;
+ }
+ }
+
+ if (_func_name) {
+ *func_name = _func_name;
+ }
+
+ bt_dwarf_cu_destroy(cu);
+ return 0;
+
+error:
+ bt_dwarf_cu_destroy(cu);
+ return -1;
+}
+
+BT_HIDDEN
+int so_info_lookup_function_name(struct so_info *so, uint64_t addr,
+ char **func_name)
+{
+ int ret = 0;
+ char *_func_name = NULL;
+
+ if (!so || !func_name) {
+ goto error;
+ }
+
+ /* Set DWARF info if it hasn't been accessed yet. */
+ if (!so->dwarf_info && !so->is_elf_only) {
+ ret = so_info_set_dwarf_info(so);
+ if (ret) {
+ /* Failed to set DWARF info, fallback to ELF. */
+ so->is_elf_only = true;
+ }
+ }
+
+ if (!so_info_has_address(so, 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 (so->is_pic) {
+ addr -= so->low_addr;
+ }
+
+ if (so->is_elf_only) {
+ ret = so_info_lookup_elf_function_name(so, addr, &_func_name);
+ } else {
+ ret = so_info_lookup_dwarf_function_name(so, addr, &_func_name);
+ }
+
+ if (ret) {
+ goto error;
+ }
+
+ if (_func_name) {
+ *func_name = _func_name;
+ }
+
+ 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`.
+ *
+ * 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
+ * @returns Returns 1 if the address was found, 0 if not
+ */
+static
+int so_info_child_die_has_address(struct bt_dwarf_die *die, uint64_t addr)
+{
+ int ret = 0, contains = 0;
+
+ if (!die) {
+ goto error;
+ }
+
+ ret = bt_dwarf_die_child(die);
+ if (ret) {
+ goto error;
+ }
+
+ do {
+ int tag;
+
+ ret = bt_dwarf_die_get_tag(die, &tag);
+ if (ret) {
+ goto error;
+ }
+
+ if (tag == DW_TAG_inlined_subroutine) {
+ ret = bt_dwarf_die_contains_addr(die, addr, &contains);
+ if (ret) {
+ goto error;
+ }
+
+ if (contains) {
+ ret = 1;
+ goto end;
+ }
+ }
+ } while (bt_dwarf_die_next(die) == 0);
+
+end:
+ return ret;
+
+error:
+ ret = 0;
+ goto end;
+}
+
+/**
+ * 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 so_info_lookup_cu_src_loc_inl(struct bt_dwarf_cu *cu, uint64_t addr,
+ struct source_location **src_loc)
+{
+ int ret = 0, found = 0;
+ 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) {
+ int contains = 0;
+
+ 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.
+ */
+ found = so_info_child_die_has_address(
+ die, addr);
+ 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
+ * @returns 0 on success, -1 on failure
+ */
+static
+int so_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, 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) {
+ goto error;
+ }
+
+ 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 = strdup(filename);
+ }
+
+ bt_dwarf_die_destroy(die);
+
+ if (_src_loc) {
+ *src_loc = _src_loc;
+ }
+
+ return 0;
+
+error:
+ source_location_destroy(_src_loc);
+ bt_dwarf_die_destroy(die);
+ return -1;
+}
+
+/**
+ * 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 so 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 so_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 = so_info_lookup_cu_src_loc_inl(cu, addr, &_src_loc);
+ if (ret) {
+ goto error;
+ }
+
+ if (_src_loc) {
+ goto end;
+ }
+
+ ret = so_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 so_info_lookup_source_location(struct so_info *so, uint64_t addr,
+ struct source_location **src_loc)
+{
+ struct bt_dwarf_cu *cu = NULL;
+ struct source_location *_src_loc = NULL;
+
+ if (!so || !src_loc) {
+ goto error;
+ }
+
+ /* Set DWARF info if it hasn't been accessed yet. */
+ if (!so->dwarf_info && !so->is_elf_only) {
+ if (so_info_set_dwarf_info(so)) {
+ /* Failed to set DWARF info. */
+ so->is_elf_only = true;
+ }
+ }
+
+ if (so->is_elf_only) {
+ /* We cannot lookup source location without DWARF info. */
+ goto error;
+ }
+
+ if (!so_info_has_address(so, 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 (so->is_pic) {
+ addr -= so->low_addr;
+ }
+
+ cu = bt_dwarf_cu_create(so->dwarf_info);
+ if (!cu) {
+ goto error;
+ }
+
+ while (bt_dwarf_cu_next(cu) == 0) {
+ int ret;
+
+ ret = so_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 / commitdiff
