The Tor Browser: comparison toolkit/crashreporter/google-breakpad/src/common/linux/dump

--1:000000000000
+:d3e14d9702dd
+// Copyright (c) 2011 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Restructured in 2009 by: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
+// dump_symbols.cc: implement google_breakpad::WriteSymbolFile:
+// Find all the debugging info in a file and dump it as a Breakpad symbol file.
+#include "common/linux/dump_symbols.h"
+#include <assert.h>
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <link.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <iostream>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+#include "common/arm_ex_reader.h"
+#include "common/dwarf/bytereader-inl.h"
+#include "common/dwarf/dwarf2diehandler.h"
+#include "common/dwarf_cfi_to_module.h"
+#include "common/dwarf_cu_to_module.h"
+#include "common/dwarf_line_to_module.h"
+#include "common/linux/elfutils.h"
+#include "common/linux/elfutils-inl.h"
+#include "common/linux/elf_symbols_to_module.h"
+#include "common/linux/file_id.h"
+#include "common/module.h"
+#include "common/scoped_ptr.h"
+#ifndef NO_STABS_SUPPORT
+#include "common/stabs_reader.h"
+#include "common/stabs_to_module.h"
+#endif
+#include "common/using_std_string.h"
+#include "common/logging.h"
+#ifndef SHT_ARM_EXIDX
+// bionic and older glibc don't define it
+# define SHT_ARM_EXIDX (SHT_LOPROC + 1)
+#endif
+// This namespace contains helper functions.
+namespace {
+using google_breakpad::DwarfCFIToModule;
+using google_breakpad::DwarfCUToModule;
+using google_breakpad::DwarfLineToModule;
+using google_breakpad::ElfClass;
+using google_breakpad::ElfClass32;
+using google_breakpad::ElfClass64;
+using google_breakpad::FindElfSectionByName;
+using google_breakpad::GetOffset;
+using google_breakpad::IsValidElf;
+using google_breakpad::Module;
+#ifndef NO_STABS_SUPPORT
+using google_breakpad::StabsToModule;
+#endif
+using google_breakpad::UniqueString;
+using google_breakpad::scoped_ptr;
+//
+// FDWrapper
+//
+// Wrapper class to make sure opened file is closed.
+//
+class FDWrapper {
+public:
+explicit FDWrapper(int fd) :
+fd_(fd) {}
+~FDWrapper() {
+if (fd_ != -1)
+close(fd_);
+}
+int get() {
+return fd_;
+}
+int release() {
+int fd = fd_;
+fd_ = -1;
+return fd;
+}
+private:
+int fd_;
+};
+//
+// MmapWrapper
+//
+// Wrapper class to make sure mapped regions are unmapped.
+//
+class MmapWrapper {
+public:
+MmapWrapper() : is_set_(false) {}
+~MmapWrapper() {
+if (is_set_ && base_ != NULL) {
+assert(size_ > 0);
+munmap(base_, size_);
+}
+}
+void set(void *mapped_address, size_t mapped_size) {
+is_set_ = true;
+base_ = mapped_address;
+size_ = mapped_size;
+}
+void release() {
+assert(is_set_);
+is_set_ = false;
+base_ = NULL;
+size_ = 0;
+}
+private:
+bool is_set_;
+void *base_;
+size_t size_;
+};
+// Find the preferred loading address of the binary.
+template<typename ElfClass>
+typename ElfClass::Addr GetLoadingAddress(
+const typename ElfClass::Phdr* program_headers,
+int nheader) {
+typedef typename ElfClass::Phdr Phdr;
+for (int i = 0; i < nheader; ++i) {
+const Phdr& header = program_headers[i];
+// For executable, it is the PT_LOAD segment with offset to zero.
+if (header.p_type == PT_LOAD &&
+header.p_offset == 0)
+return header.p_vaddr;
+}
+// For other types of ELF, return 0.
+return 0;
+}
+#ifndef NO_STABS_SUPPORT
+template<typename ElfClass>
+bool LoadStabs(const typename ElfClass::Ehdr* elf_header,
+const typename ElfClass::Shdr* stab_section,
+const typename ElfClass::Shdr* stabstr_section,
+const bool big_endian,
+Module* module) {
+// A callback object to handle data from the STABS reader.
+StabsToModule handler(module);
+// Find the addresses of the STABS data, and create a STABS reader object.
+// On Linux, STABS entries always have 32-bit values, regardless of the
+// address size of the architecture whose code they're describing, and
+// the strings are always "unitized".
+const uint8_t* stabs =
+GetOffset<ElfClass, uint8_t>(elf_header, stab_section->sh_offset);
+const uint8_t* stabstr =
+GetOffset<ElfClass, uint8_t>(elf_header, stabstr_section->sh_offset);
+google_breakpad::StabsReader reader(stabs, stab_section->sh_size,
+stabstr, stabstr_section->sh_size,
+big_endian, 4, true, &handler);
+// Read the STABS data, and do post-processing.
+if (!reader.Process())
+return false;
+handler.Finalize();
+return true;
+}
+#endif  // NO_STABS_SUPPORT
+// A line-to-module loader that accepts line number info parsed by
+// dwarf2reader::LineInfo and populates a Module and a line vector
+// with the results.
+class DumperLineToModule: public DwarfCUToModule::LineToModuleHandler {
+public:
+// Create a line-to-module converter using BYTE_READER.
+explicit DumperLineToModule(dwarf2reader::ByteReader *byte_reader)
+: byte_reader_(byte_reader) { }
+void StartCompilationUnit(const string& compilation_dir) {
+compilation_dir_ = compilation_dir;
+}
+void ReadProgram(const char *program, uint64 length,
+Module *module, std::vector<Module::Line> *lines) {
+DwarfLineToModule handler(module, compilation_dir_, lines);
+dwarf2reader::LineInfo parser(program, length, byte_reader_, &handler);
+parser.Start();
+}
+private:
+string compilation_dir_;
+dwarf2reader::ByteReader *byte_reader_;
+};
+template<typename ElfClass>
+bool LoadDwarf(const string& dwarf_filename,
+const typename ElfClass::Ehdr* elf_header,
+const bool big_endian,
+Module* module) {
+typedef typename ElfClass::Shdr Shdr;
+const dwarf2reader::Endianness endianness = big_endian ?
+dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE;
+dwarf2reader::ByteReader byte_reader(endianness);
+// Construct a context for this file.
+DwarfCUToModule::FileContext file_context(dwarf_filename, module);
+// Build a map of the ELF file's sections.
+const Shdr* sections =
+GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
+int num_sections = elf_header->e_shnum;
+const Shdr* section_names = sections + elf_header->e_shstrndx;
+for (int i = 0; i < num_sections; i++) {
+const Shdr* section = &sections[i];
+string name = GetOffset<ElfClass, char>(elf_header,
+section_names->sh_offset) +
+section->sh_name;
+const char* contents = GetOffset<ElfClass, char>(elf_header,
+section->sh_offset);
+uint64 length = section->sh_size;
+file_context.section_map[name] = std::make_pair(contents, length);
+}
+// Parse all the compilation units in the .debug_info section.
+DumperLineToModule line_to_module(&byte_reader);
+std::pair<const char *, uint64> debug_info_section
+= file_context.section_map[".debug_info"];
+// This should never have been called if the file doesn't have a
+// .debug_info section.
+assert(debug_info_section.first);
+uint64 debug_info_length = debug_info_section.second;
+for (uint64 offset = 0; offset < debug_info_length;) {
+// Make a handler for the root DIE that populates MODULE with the
+// data that was found.
+DwarfCUToModule::WarningReporter reporter(dwarf_filename, offset);
+DwarfCUToModule root_handler(&file_context, &line_to_module, &reporter);
+// Make a Dwarf2Handler that drives the DIEHandler.
+dwarf2reader::DIEDispatcher die_dispatcher(&root_handler);
+// Make a DWARF parser for the compilation unit at OFFSET.
+dwarf2reader::CompilationUnit reader(file_context.section_map,
+offset,
+&byte_reader,
+&die_dispatcher);
+// Process the entire compilation unit; get the offset of the next.
+offset += reader.Start();
+}
+return true;
+}
+// Fill REGISTER_NAMES with the register names appropriate to the
+// machine architecture given in HEADER, indexed by the register
+// numbers used in DWARF call frame information. Return true on
+// success, or false if HEADER's machine architecture is not
+// supported.
+template<typename ElfClass>
+bool DwarfCFIRegisterNames(const typename ElfClass::Ehdr* elf_header,
+std::vector<const UniqueString*>* register_names) {
+switch (elf_header->e_machine) {
+case EM_386:
+*register_names = DwarfCFIToModule::RegisterNames::I386();
+return true;
+case EM_ARM:
+*register_names = DwarfCFIToModule::RegisterNames::ARM();
+return true;
+case EM_X86_64:
+*register_names = DwarfCFIToModule::RegisterNames::X86_64();
+return true;
+default:
+return false;
+}
+}
+template<typename ElfClass>
+bool LoadDwarfCFI(const string& dwarf_filename,
+const typename ElfClass::Ehdr* elf_header,
+const char* section_name,
+const typename ElfClass::Shdr* section,
+const bool eh_frame,
+const typename ElfClass::Shdr* got_section,
+const typename ElfClass::Shdr* text_section,
+const bool big_endian,
+Module* module) {
+// Find the appropriate set of register names for this file's
+// architecture.
+std::vector<const UniqueString*> register_names;
+if (!DwarfCFIRegisterNames<ElfClass>(elf_header, &register_names)) {
+fprintf(stderr, "%s: unrecognized ELF machine architecture '%d';"
+" cannot convert DWARF call frame information\n",
+dwarf_filename.c_str(), elf_header->e_machine);
+return false;
+}
+const dwarf2reader::Endianness endianness = big_endian ?
+dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE;
+// Find the call frame information and its size.
+const char* cfi =
+GetOffset<ElfClass, char>(elf_header, section->sh_offset);
+size_t cfi_size = section->sh_size;
+// Plug together the parser, handler, and their entourages.
+DwarfCFIToModule::Reporter module_reporter(dwarf_filename, section_name);
+DwarfCFIToModule handler(module, register_names, &module_reporter);
+dwarf2reader::ByteReader byte_reader(endianness);
+byte_reader.SetAddressSize(ElfClass::kAddrSize);
+// Provide the base addresses for .eh_frame encoded pointers, if
+// possible.
+byte_reader.SetCFIDataBase(section->sh_addr, cfi);
+if (got_section)
+byte_reader.SetDataBase(got_section->sh_addr);
+if (text_section)
+byte_reader.SetTextBase(text_section->sh_addr);
+dwarf2reader::CallFrameInfo::Reporter dwarf_reporter(dwarf_filename,
+section_name);
+dwarf2reader::CallFrameInfo parser(cfi, cfi_size,
+&byte_reader, &handler, &dwarf_reporter,
+eh_frame);
+parser.Start();
+return true;
+}
+template<typename ElfClass>
+bool LoadARMexidx(const typename ElfClass::Ehdr* elf_header,
+const typename ElfClass::Shdr* exidx_section,
+const typename ElfClass::Shdr* extab_section,
+uint32_t loading_addr,
+Module* module) {
+// To do this properly we need to know:
+// * the bounds of the .ARM.exidx section in the mapped image
+// * the bounds of the .ARM.extab section in the mapped image
+// * the vma of the last byte in the text section associated with the .exidx
+// The first two are easy.  The third is a bit tricky.  If we can't
+// figure out what it is, just pass in zero.
+const char *exidx_img
+= GetOffset<ElfClass, char>(elf_header, exidx_section->sh_offset);
+size_t exidx_size = exidx_section->sh_size;
+const char *extab_img
+= GetOffset<ElfClass, char>(elf_header, extab_section->sh_offset);
+size_t extab_size = extab_section->sh_size;
+// The sh_link field of the exidx section gives the section number
+// for the associated text section.
+uint32_t exidx_text_last_svma = 0;
+int exidx_text_sno = exidx_section->sh_link;
+typedef typename ElfClass::Shdr Shdr;
+// |sections| points to the section header table
+const Shdr* sections
+= GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
+const int num_sections = elf_header->e_shnum;
+if (exidx_text_sno >= 0 && exidx_text_sno < num_sections) {
+const Shdr* exidx_text_shdr = &sections[exidx_text_sno];
+if (exidx_text_shdr->sh_size > 0) {
+exidx_text_last_svma
+= exidx_text_shdr->sh_addr + exidx_text_shdr->sh_size - 1;
+}
+}
+arm_ex_to_module::ARMExToModule handler(module);
+arm_ex_reader::ExceptionTableInfo
+parser(exidx_img, exidx_size, extab_img, extab_size, exidx_text_last_svma,
+&handler,
+reinterpret_cast<const char*>(elf_header),
+loading_addr);
+parser.Start();
+return true;
+}
+bool LoadELF(const string& obj_file, MmapWrapper* map_wrapper,
+void** elf_header) {
+int obj_fd = open(obj_file.c_str(), O_RDONLY);
+if (obj_fd < 0) {
+fprintf(stderr, "Failed to open ELF file '%s': %s\n",
+obj_file.c_str(), strerror(errno));
+return false;
+}
+FDWrapper obj_fd_wrapper(obj_fd);
+struct stat st;
+if (fstat(obj_fd, &st) != 0 && st.st_size <= 0) {
+fprintf(stderr, "Unable to fstat ELF file '%s': %s\n",
+obj_file.c_str(), strerror(errno));
+return false;
+}
+void *obj_base = mmap(NULL, st.st_size,
+PROT_READ | PROT_WRITE, MAP_PRIVATE, obj_fd, 0);
+if (obj_base == MAP_FAILED) {
+fprintf(stderr, "Failed to mmap ELF file '%s': %s\n",
+obj_file.c_str(), strerror(errno));
+return false;
+}
+map_wrapper->set(obj_base, st.st_size);
+*elf_header = obj_base;
+if (!IsValidElf(*elf_header)) {
+fprintf(stderr, "Not a valid ELF file: %s\n", obj_file.c_str());
+return false;
+}
+return true;
+}
+// Get the endianness of ELF_HEADER. If it's invalid, return false.
+template<typename ElfClass>
+bool ElfEndianness(const typename ElfClass::Ehdr* elf_header,
+bool* big_endian) {
+if (elf_header->e_ident[EI_DATA] == ELFDATA2LSB) {
+*big_endian = false;
+return true;
+}
+if (elf_header->e_ident[EI_DATA] == ELFDATA2MSB) {
+*big_endian = true;
+return true;
+}
+fprintf(stderr, "bad data encoding in ELF header: %d\n",
+elf_header->e_ident[EI_DATA]);
+return false;
+}
+// Read the .gnu_debuglink and get the debug file name. If anything goes
+// wrong, return an empty string.
+template<typename ElfClass>
+string ReadDebugLink(const char* debuglink,
+size_t debuglink_size,
+const string& obj_file,
+const std::vector<string>& debug_dirs) {
+size_t debuglink_len = strlen(debuglink) + 5;  // '\0' + CRC32.
+debuglink_len = 4 * ((debuglink_len + 3) / 4);  // Round to nearest 4 bytes.
+// Sanity check.
+if (debuglink_len != debuglink_size) {
+fprintf(stderr, "Mismatched .gnu_debuglink string / section size: "
+"%zx %zx\n", debuglink_len, debuglink_size);
+return "";
+}
+bool found = false;
+int debuglink_fd = -1;
+string debuglink_path;
+std::vector<string>::const_iterator it;
+for (it = debug_dirs.begin(); it < debug_dirs.end(); ++it) {
+const string& debug_dir = *it;
+debuglink_path = debug_dir + "/" + debuglink;
+debuglink_fd = open(debuglink_path.c_str(), O_RDONLY);
+if (debuglink_fd >= 0) {
+found = true;
+break;
+}
+}
+if (!found) {
+fprintf(stderr, "Failed to find debug ELF file for '%s' after trying:\n",
+obj_file.c_str());
+for (it = debug_dirs.begin(); it < debug_dirs.end(); ++it) {
+const string debug_dir = *it;
+fprintf(stderr, "  %s/%s\n", debug_dir.c_str(), debuglink);
+}
+return "";
+}
+FDWrapper debuglink_fd_wrapper(debuglink_fd);
+// TODO(thestig) check the CRC-32 at the end of the .gnu_debuglink
+// section.
+return debuglink_path;
+}
+//
+// LoadSymbolsInfo
+//
+// Holds the state between the two calls to LoadSymbols() in case it's necessary
+// to follow the .gnu_debuglink section and load debug information from a
+// different file.
+//
+template<typename ElfClass>
+class LoadSymbolsInfo {
+public:
+typedef typename ElfClass::Addr Addr;
+explicit LoadSymbolsInfo(const std::vector<string>& dbg_dirs) :
+debug_dirs_(dbg_dirs),
+has_loading_addr_(false) {}
+// Keeps track of which sections have been loaded so sections don't
+// accidentally get loaded twice from two different files.
+void LoadedSection(const string &section) {
+if (loaded_sections_.count(section) == 0) {
+loaded_sections_.insert(section);
+} else {
+fprintf(stderr, "Section %s has already been loaded.\n",
+section.c_str());
+}
+}
+// The ELF file and linked debug file are expected to have the same preferred
+// loading address.
+void set_loading_addr(Addr addr, const string &filename) {
+if (!has_loading_addr_) {
+loading_addr_ = addr;
+loaded_file_ = filename;
+return;
+}
+if (addr != loading_addr_) {
+fprintf(stderr,
+"ELF file '%s' and debug ELF file '%s' "
+"have different load addresses.\n",
+loaded_file_.c_str(), filename.c_str());
+assert(false);
+}
+}
+// Setters and getters
+const std::vector<string>& debug_dirs() const {
+return debug_dirs_;
+}
+string debuglink_file() const {
+return debuglink_file_;
+}
+void set_debuglink_file(string file) {
+debuglink_file_ = file;
+}
+private:
+const std::vector<string>& debug_dirs_; // Directories in which to
+// search for the debug ELF file.
+string debuglink_file_;  // Full path to the debug ELF file.
+bool has_loading_addr_;  // Indicate if LOADING_ADDR_ is valid.
+Addr loading_addr_;  // Saves the preferred loading address from the
+// first call to LoadSymbols().
+string loaded_file_;  // Name of the file loaded from the first call to
+// LoadSymbols().
+std::set<string> loaded_sections_;  // Tracks the Loaded ELF sections
+// between calls to LoadSymbols().
+};
+template<typename ElfClass>
+bool LoadSymbols(const string& obj_file,
+const bool big_endian,
+const typename ElfClass::Ehdr* elf_header,
+const bool read_gnu_debug_link,
+LoadSymbolsInfo<ElfClass>* info,
+SymbolData symbol_data,
+Module* module) {
+typedef typename ElfClass::Addr Addr;
+typedef typename ElfClass::Phdr Phdr;
+typedef typename ElfClass::Shdr Shdr;
+BPLOG(INFO) << "";
+BPLOG(INFO) << "LoadSymbols: BEGIN   " << obj_file;
+Addr loading_addr = GetLoadingAddress<ElfClass>(
+GetOffset<ElfClass, Phdr>(elf_header, elf_header->e_phoff),
+elf_header->e_phnum);
+module->SetLoadAddress(loading_addr);
+info->set_loading_addr(loading_addr, obj_file);
+const Shdr* sections =
+GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
+const Shdr* section_names = sections + elf_header->e_shstrndx;
+const char* names =
+GetOffset<ElfClass, char>(elf_header, section_names->sh_offset);
+const char *names_end = names + section_names->sh_size;
+bool found_debug_info_section = false;
+bool found_usable_info = false;
+if (symbol_data != ONLY_CFI) {
+#ifndef NO_STABS_SUPPORT
+// Look for STABS debugging information, and load it if present.
+const Shdr* stab_section =
+FindElfSectionByName<ElfClass>(".stab", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+if (stab_section) {
+const Shdr* stabstr_section = stab_section->sh_link + sections;
+if (stabstr_section) {
+found_debug_info_section = true;
+found_usable_info = true;
+info->LoadedSection(".stab");
+if (!LoadStabs<ElfClass>(elf_header, stab_section, stabstr_section,
+big_endian, module)) {
+fprintf(stderr, "%s: \".stab\" section found, but failed to load"
+" STABS debugging information\n", obj_file.c_str());
+}
+}
+}
+#endif  // NO_STABS_SUPPORT
+// Look for DWARF debugging information, and load it if present.
+const Shdr* dwarf_section =
+FindElfSectionByName<ElfClass>(".debug_info", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+if (dwarf_section) {
+found_debug_info_section = true;
+found_usable_info = true;
+info->LoadedSection(".debug_info");
+if (!LoadDwarf<ElfClass>(obj_file, elf_header, big_endian, module))
+fprintf(stderr, "%s: \".debug_info\" section found, but failed to load "
+"DWARF debugging information\n", obj_file.c_str());
+}
+}
+if (symbol_data != NO_CFI) {
+// Dwarf Call Frame Information (CFI) is actually independent from
+// the other DWARF debugging information, and can be used alone.
+const Shdr* dwarf_cfi_section =
+FindElfSectionByName<ElfClass>(".debug_frame", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+if (dwarf_cfi_section) {
+// Ignore the return value of this function; even without call frame
+// information, the other debugging information could be perfectly
+// useful.
+info->LoadedSection(".debug_frame");
+bool result =
+LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".debug_frame",
+dwarf_cfi_section, false, 0, 0, big_endian,
+module);
+found_usable_info = found_usable_info || result;
+if (result)
+BPLOG(INFO) << "LoadSymbols:   read CFI from .debug_frame";
+}
+// Linux C++ exception handling information can also provide
+// unwinding data.
+const Shdr* eh_frame_section =
+FindElfSectionByName<ElfClass>(".eh_frame", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+if (eh_frame_section) {
+// Pointers in .eh_frame data may be relative to the base addresses of
+// certain sections. Provide those sections if present.
+const Shdr* got_section =
+FindElfSectionByName<ElfClass>(".got", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+const Shdr* text_section =
+FindElfSectionByName<ElfClass>(".text", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+info->LoadedSection(".eh_frame");
+// As above, ignore the return value of this function.
+bool result =
+LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".eh_frame",
+eh_frame_section, true,
+got_section, text_section, big_endian, module);
+found_usable_info = found_usable_info || result;
+if (result)
+BPLOG(INFO) << "LoadSymbols:   read CFI from .eh_frame";
+}
+}
+// ARM has special unwind tables that can be used.
+const Shdr* arm_exidx_section =
+FindElfSectionByName<ElfClass>(".ARM.exidx", SHT_ARM_EXIDX,
+sections, names, names_end,
+elf_header->e_shnum);
+const Shdr* arm_extab_section =
+FindElfSectionByName<ElfClass>(".ARM.extab", SHT_PROGBITS,
+sections, names, names_end,
+elf_header->e_shnum);
+// Only load information from this section if there isn't a .debug_info
+// section.
+if (!found_debug_info_section
+&& arm_exidx_section && arm_extab_section && symbol_data != NO_CFI) {
+info->LoadedSection(".ARM.exidx");
+info->LoadedSection(".ARM.extab");
+bool result = LoadARMexidx<ElfClass>(elf_header,
+arm_exidx_section, arm_extab_section,
+loading_addr, module);
+found_usable_info = found_usable_info || result;
+if (result)
+BPLOG(INFO) << "LoadSymbols:   read EXIDX from .ARM.{exidx,extab}";
+}
+if (!found_debug_info_section && symbol_data != ONLY_CFI) {
+fprintf(stderr, "%s: file contains no debugging information"
+" (no \".stab\" or \".debug_info\" sections)\n",
+obj_file.c_str());
+// Failed, but maybe there's a .gnu_debuglink section?
+if (read_gnu_debug_link) {
+const Shdr* gnu_debuglink_section
+= FindElfSectionByName<ElfClass>(".gnu_debuglink", SHT_PROGBITS,
+sections, names,
+names_end, elf_header->e_shnum);
+if (gnu_debuglink_section) {
+if (!info->debug_dirs().empty()) {
+const char* debuglink_contents =
+GetOffset<ElfClass, char>(elf_header,
+gnu_debuglink_section->sh_offset);
+string debuglink_file
+= ReadDebugLink<ElfClass>(debuglink_contents,
+gnu_debuglink_section->sh_size,
+obj_file, info->debug_dirs());
+info->set_debuglink_file(debuglink_file);
+} else {
+fprintf(stderr, ".gnu_debuglink section found in '%s', "
+"but no debug path specified.\n", obj_file.c_str());
+}
+} else {
+fprintf(stderr, "%s does not contain a .gnu_debuglink section.\n",
+obj_file.c_str());
+}
+} else {
+if (symbol_data != ONLY_CFI) {
+// The caller doesn't want to consult .gnu_debuglink.
+// See if there are export symbols available.
+const Shdr* dynsym_section =
+FindElfSectionByName<ElfClass>(".dynsym", SHT_DYNSYM,
+sections, names, names_end,
+elf_header->e_shnum);
+const Shdr* dynstr_section =
+FindElfSectionByName<ElfClass>(".dynstr", SHT_STRTAB,
+sections, names, names_end,
+elf_header->e_shnum);
+if (dynsym_section && dynstr_section) {
+info->LoadedSection(".dynsym");
+const uint8_t* dynsyms =
+GetOffset<ElfClass, uint8_t>(elf_header,
+dynsym_section->sh_offset);
+const uint8_t* dynstrs =
+GetOffset<ElfClass, uint8_t>(elf_header,
+dynstr_section->sh_offset);
+bool result =
+ELFSymbolsToModule(dynsyms,
+dynsym_section->sh_size,
+dynstrs,
+dynstr_section->sh_size,
+big_endian,
+ElfClass::kAddrSize,
+module);
+found_usable_info = found_usable_info || result;
+}
+}
+// Return true if some usable information was found, since
+// the caller doesn't want to use .gnu_debuglink.
+BPLOG(INFO) << "LoadSymbols: "
+<< (found_usable_info ? "SUCCESS " : "FAILURE ")
+<< obj_file;
+return found_usable_info;
+}
+// No debug info was found, let the user try again with .gnu_debuglink
+// if present.
+BPLOG(INFO) << "LoadSymbols: FAILURE " << obj_file;
+return false;
+}
+BPLOG(INFO) << "LoadSymbols: SUCCESS " << obj_file;
+return true;
+}
+// Return the breakpad symbol file identifier for the architecture of
+// ELF_HEADER.
+template<typename ElfClass>
+const char* ElfArchitecture(const typename ElfClass::Ehdr* elf_header) {
+typedef typename ElfClass::Half Half;
+Half arch = elf_header->e_machine;
+switch (arch) {
+case EM_386:        return "x86";
+case EM_ARM:        return "arm";
+case EM_MIPS:       return "mips";
+case EM_PPC64:      return "ppc64";
+case EM_PPC:        return "ppc";
+case EM_S390:       return "s390";
+case EM_SPARC:      return "sparc";
+case EM_SPARCV9:    return "sparcv9";
+case EM_X86_64:     return "x86_64";
+default: return NULL;
+}
+}
+// Format the Elf file identifier in IDENTIFIER as a UUID with the
+// dashes removed.
+string FormatIdentifier(unsigned char identifier[16]) {
+char identifier_str[40];
+google_breakpad::FileID::ConvertIdentifierToString(
+identifier,
+identifier_str,
+sizeof(identifier_str));
+string id_no_dash;
+for (int i = 0; identifier_str[i] != '\0'; ++i)
+if (identifier_str[i] != '-')
+id_no_dash += identifier_str[i];
+// Add an extra "0" by the end.  PDB files on Windows have an 'age'
+// number appended to the end of the file identifier; this isn't
+// really used or necessary on other platforms, but be consistent.
+id_no_dash += '0';
+return id_no_dash;
+}
+// Return the non-directory portion of FILENAME: the portion after the
+// last slash, or the whole filename if there are no slashes.
+string BaseFileName(const string &filename) {
+// Lots of copies!  basename's behavior is less than ideal.
+char *c_filename = strdup(filename.c_str());
+string base = basename(c_filename);
+free(c_filename);
+return base;
+}
+template<typename ElfClass>
+bool ReadSymbolDataElfClass(const typename ElfClass::Ehdr* elf_header,
+const string& obj_filename,
+const std::vector<string>& debug_dirs,
+SymbolData symbol_data,
+Module** out_module) {
+typedef typename ElfClass::Ehdr Ehdr;
+typedef typename ElfClass::Shdr Shdr;
+*out_module = NULL;
+unsigned char identifier[16];
+if (!google_breakpad::FileID::ElfFileIdentifierFromMappedFile(elf_header,
+identifier)) {
+fprintf(stderr, "%s: unable to generate file identifier\n",
+obj_filename.c_str());
+return false;
+}
+const char *architecture = ElfArchitecture<ElfClass>(elf_header);
+if (!architecture) {
+fprintf(stderr, "%s: unrecognized ELF machine architecture: %d\n",
+obj_filename.c_str(), elf_header->e_machine);
+return false;
+}
+// Figure out what endianness this file is.
+bool big_endian;
+if (!ElfEndianness<ElfClass>(elf_header, &big_endian))
+return false;
+string name = BaseFileName(obj_filename);
+string os = "Linux";
+string id = FormatIdentifier(identifier);
+LoadSymbolsInfo<ElfClass> info(debug_dirs);
+scoped_ptr<Module> module(new Module(name, os, architecture, id));
+if (!LoadSymbols<ElfClass>(obj_filename, big_endian, elf_header,
+!debug_dirs.empty(), &info,
+symbol_data, module.get())) {
+const string debuglink_file = info.debuglink_file();
+if (debuglink_file.empty())
+return false;
+// Load debuglink ELF file.
+fprintf(stderr, "Found debugging info in %s\n", debuglink_file.c_str());
+MmapWrapper debug_map_wrapper;
+Ehdr* debug_elf_header = NULL;
+if (!LoadELF(debuglink_file, &debug_map_wrapper,
+reinterpret_cast<void**>(&debug_elf_header)))
+return false;
+// Sanity checks to make sure everything matches up.
+const char *debug_architecture =
+ElfArchitecture<ElfClass>(debug_elf_header);
+if (!debug_architecture) {
+fprintf(stderr, "%s: unrecognized ELF machine architecture: %d\n",
+debuglink_file.c_str(), debug_elf_header->e_machine);
+return false;
+}
+if (strcmp(architecture, debug_architecture)) {
+fprintf(stderr, "%s with ELF machine architecture %s does not match "
+"%s with ELF architecture %s\n",
+debuglink_file.c_str(), debug_architecture,
+obj_filename.c_str(), architecture);
+return false;
+}
+bool debug_big_endian;
+if (!ElfEndianness<ElfClass>(debug_elf_header, &debug_big_endian))
+return false;
+if (debug_big_endian != big_endian) {
+fprintf(stderr, "%s and %s does not match in endianness\n",
+obj_filename.c_str(), debuglink_file.c_str());
+return false;
+}
+if (!LoadSymbols<ElfClass>(debuglink_file, debug_big_endian,
+debug_elf_header, false, &info,
+symbol_data, module.get())) {
+return false;
+}
+}
+*out_module = module.release();
+return true;
+}
+}  // namespace
+namespace google_breakpad {
+// Not explicitly exported, but not static so it can be used in unit tests.
+bool ReadSymbolDataInternal(const uint8_t* obj_file,
+const string& obj_filename,
+const std::vector<string>& debug_dirs,
+SymbolData symbol_data,
+Module** module) {
+if (!IsValidElf(obj_file)) {
+fprintf(stderr, "Not a valid ELF file: %s\n", obj_filename.c_str());
+return false;
+}
+int elfclass = ElfClass(obj_file);
+if (elfclass == ELFCLASS32) {
+return ReadSymbolDataElfClass<ElfClass32>(
+reinterpret_cast<const Elf32_Ehdr*>(obj_file), obj_filename, debug_dirs,
+symbol_data, module);
+}
+if (elfclass == ELFCLASS64) {
+return ReadSymbolDataElfClass<ElfClass64>(
+reinterpret_cast<const Elf64_Ehdr*>(obj_file), obj_filename, debug_dirs,
+symbol_data, module);
+}
+return false;
+}
+bool WriteSymbolFile(const string &obj_file,
+const std::vector<string>& debug_dirs,
+SymbolData symbol_data,
+std::ostream &sym_stream) {
+Module* module;
+if (!ReadSymbolData(obj_file, debug_dirs, symbol_data, &module))
+return false;
+bool result = module->Write(sym_stream, symbol_data);
+delete module;
+return result;
+}
+bool ReadSymbolData(const string& obj_file,
+const std::vector<string>& debug_dirs,
+SymbolData symbol_data,
+Module** module) {
+MmapWrapper map_wrapper;
+void* elf_header = NULL;
+if (!LoadELF(obj_file, &map_wrapper, &elf_header))
+return false;
+return ReadSymbolDataInternal(reinterpret_cast<uint8_t*>(elf_header),
+obj_file, debug_dirs, symbol_data, module);
+}
+}  // namespace google_breakpad

The Tor Browser / file comparison

comparison: toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc

toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc