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Diffstat (limited to 'toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc')
-rw-r--r-- | toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc | 1159 |
1 files changed, 1159 insertions, 0 deletions
diff --git a/toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc b/toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc new file mode 100644 index 000000000..cd99bee66 --- /dev/null +++ b/toolkit/crashreporter/google-breakpad/src/common/linux/dump_symbols.cc @@ -0,0 +1,1159 @@ +// 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 <stdint.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/crc32.h" +#include "common/linux/eintr_wrapper.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/memory.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" + +#ifndef SHT_ARM_EXIDX +// bionic and older glibc don't define this +# define SHT_ARM_EXIDX (SHT_LOPROC + 1) +#endif + +// This namespace contains helper functions. +namespace { + +using google_breakpad::DumpOptions; +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::FileID; +using google_breakpad::FindElfSectionByName; +using google_breakpad::GetOffset; +using google_breakpad::IsValidElf; +using google_breakpad::kDefaultBuildIdSize; +using google_breakpad::Module; +using google_breakpad::PageAllocator; +#ifndef NO_STABS_SUPPORT +using google_breakpad::StabsToModule; +#endif +using google_breakpad::scoped_ptr; +using google_breakpad::wasteful_vector; + +// Define AARCH64 ELF architecture if host machine does not include this define. +#ifndef EM_AARCH64 +#define EM_AARCH64 183 +#endif + +// Define SHT_ANDROID_REL and SHT_ANDROID_RELA if not defined by the host. +// Sections with this type contain Android packed relocations. +#ifndef SHT_ANDROID_REL +#define SHT_ANDROID_REL (SHT_LOOS + 1) +#endif +#ifndef SHT_ANDROID_RELA +#define SHT_ANDROID_RELA (SHT_LOOS + 2) +#endif + +// +// 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 non-PIC executables (e_type == ET_EXEC), the load address is + // the start address of the first PT_LOAD segment. (ELF requires + // the segments to be sorted by load address.) For PIC executables + // and dynamic libraries (e_type == ET_DYN), this address will + // normally be zero. + for (int i = 0; i < nheader; ++i) { + const Phdr& header = program_headers[i]; + if (header.p_type == PT_LOAD) + return header.p_vaddr; + } + 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 uint8_t *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, + bool handle_inter_cu_refs, + 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, + handle_inter_cu_refs); + + // 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 = §ions[i]; + string name = GetOffset<ElfClass, char>(elf_header, + section_names->sh_offset) + + section->sh_name; + const uint8_t *contents = GetOffset<ElfClass, uint8_t>(elf_header, + section->sh_offset); + file_context.AddSectionToSectionMap(name, contents, section->sh_size); + } + + // Parse all the compilation units in the .debug_info section. + DumperLineToModule line_to_module(&byte_reader); + dwarf2reader::SectionMap::const_iterator debug_info_entry = + file_context.section_map().find(".debug_info"); + assert(debug_info_entry != file_context.section_map().end()); + const std::pair<const uint8_t *, uint64>& debug_info_section = + debug_info_entry->second; + // 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(dwarf_filename, + 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<string>* 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_AARCH64: + *register_names = DwarfCFIToModule::RegisterNames::ARM64(); + return true; + case EM_MIPS: + *register_names = DwarfCFIToModule::RegisterNames::MIPS(); + 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<string> register_names; + if (!DwarfCFIRegisterNames<ElfClass>(elf_header, ®ister_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 uint8_t *cfi = + GetOffset<ElfClass, uint8_t>(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 = §ions[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; +} + +// Given |left_abspath|, find the absolute path for |right_path| and see if the +// two absolute paths are the same. +bool IsSameFile(const char* left_abspath, const string& right_path) { + char right_abspath[PATH_MAX]; + if (!realpath(right_path.c_str(), right_abspath)) + return false; + return strcmp(left_abspath, right_abspath) == 0; +} + +// Read the .gnu_debuglink and get the debug file name. If anything goes +// wrong, return an empty string. +string ReadDebugLink(const uint8_t *debuglink, + const size_t debuglink_size, + const bool big_endian, + const string& obj_file, + const std::vector<string>& debug_dirs) { + // Include '\0' + CRC32 (4 bytes). + size_t debuglink_len = strlen(reinterpret_cast<const char *>(debuglink)) + 5; + debuglink_len = 4 * ((debuglink_len + 3) / 4); // Round up to 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 string(); + } + + char obj_file_abspath[PATH_MAX]; + if (!realpath(obj_file.c_str(), obj_file_abspath)) { + fprintf(stderr, "Cannot resolve absolute path for %s\n", obj_file.c_str()); + return string(); + } + + std::vector<string> searched_paths; + 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 + "/" + + reinterpret_cast<const char *>(debuglink); + + // There is the annoying case of /path/to/foo.so having foo.so as the + // debug link file name. Thus this may end up opening /path/to/foo.so again, + // and there is a small chance of the two files having the same CRC. + if (IsSameFile(obj_file_abspath, debuglink_path)) + continue; + + searched_paths.push_back(debug_dir); + int debuglink_fd = open(debuglink_path.c_str(), O_RDONLY); + if (debuglink_fd < 0) + continue; + + FDWrapper debuglink_fd_wrapper(debuglink_fd); + + // The CRC is the last 4 bytes in |debuglink|. + const dwarf2reader::Endianness endianness = big_endian ? + dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE; + dwarf2reader::ByteReader byte_reader(endianness); + uint32_t expected_crc = + byte_reader.ReadFourBytes(&debuglink[debuglink_size - 4]); + + uint32_t actual_crc = 0; + while (true) { + const size_t kReadSize = 4096; + char buf[kReadSize]; + ssize_t bytes_read = HANDLE_EINTR(read(debuglink_fd, &buf, kReadSize)); + if (bytes_read < 0) { + fprintf(stderr, "Error reading debug ELF file %s.\n", + debuglink_path.c_str()); + return string(); + } + if (bytes_read == 0) + break; + actual_crc = google_breakpad::UpdateCrc32(actual_crc, buf, bytes_read); + } + if (actual_crc != expected_crc) { + fprintf(stderr, "Error reading debug ELF file - CRC32 mismatch: %s\n", + debuglink_path.c_str()); + continue; + } + + // Found debug file. + return debuglink_path; + } + + // Not found case. + fprintf(stderr, "Failed to find debug ELF file for '%s' after trying:\n", + obj_file.c_str()); + for (it = searched_paths.begin(); it < searched_paths.end(); ++it) { + const string& debug_dir = *it; + fprintf(stderr, " %s/%s\n", debug_dir.c_str(), debuglink); + } + return string(); +} + +// +// 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 §ion) { + 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, + const DumpOptions& options, + Module* module) { + typedef typename ElfClass::Addr Addr; + typedef typename ElfClass::Phdr Phdr; + typedef typename ElfClass::Shdr Shdr; + typedef typename ElfClass::Word Word; + + 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); + + Word debug_section_type = + elf_header->e_machine == EM_MIPS ? SHT_MIPS_DWARF : SHT_PROGBITS; + 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; + + // Reject files that contain Android packed relocations. The pre-packed + // version of the file should be symbolized; the packed version is only + // intended for use on the target system. + if (FindElfSectionByName<ElfClass>(".rel.dyn", SHT_ANDROID_REL, + sections, names, + names_end, elf_header->e_shnum)) { + fprintf(stderr, "%s: file contains a \".rel.dyn\" section " + "with type SHT_ANDROID_REL\n", obj_file.c_str()); + fprintf(stderr, "Files containing Android packed relocations " + "may not be symbolized.\n"); + return false; + } + if (FindElfSectionByName<ElfClass>(".rela.dyn", SHT_ANDROID_RELA, + sections, names, + names_end, elf_header->e_shnum)) { + fprintf(stderr, "%s: file contains a \".rela.dyn\" section " + "with type SHT_ANDROID_RELA\n", obj_file.c_str()); + fprintf(stderr, "Files containing Android packed relocations " + "may not be symbolized.\n"); + return false; + } + + if (options.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", debug_section_type, + 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, + options.handle_inter_cu_refs, module)) { + fprintf(stderr, "%s: \".debug_info\" section found, but failed to load " + "DWARF debugging information\n", obj_file.c_str()); + } + } + + // See if there are export symbols available. + const Shdr* symtab_section = + FindElfSectionByName<ElfClass>(".symtab", SHT_SYMTAB, + sections, names, names_end, + elf_header->e_shnum); + const Shdr* strtab_section = + FindElfSectionByName<ElfClass>(".strtab", SHT_STRTAB, + sections, names, names_end, + elf_header->e_shnum); + if (symtab_section && strtab_section) { + info->LoadedSection(".symtab"); + + const uint8_t* symtab = + GetOffset<ElfClass, uint8_t>(elf_header, + symtab_section->sh_offset); + const uint8_t* strtab = + GetOffset<ElfClass, uint8_t>(elf_header, + strtab_section->sh_offset); + bool result = + ELFSymbolsToModule(symtab, + symtab_section->sh_size, + strtab, + strtab_section->sh_size, + big_endian, + ElfClass::kAddrSize, + module); + found_usable_info = found_usable_info || result; + } else { + // Look in dynsym only if full symbol table was not 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; + } + } + } + + if (options.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", debug_section_type, + 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; + } + + // 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; + } + } + + // 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); + // Load information from these sections even if there is + // .debug_info, because some functions (e.g., hand-written or + // script-generated assembly) could have exidx entries but no DWARF. + // (For functions with both, the DWARF info that has already been + // parsed will take precedence.) + if (arm_exidx_section && arm_extab_section && options.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 (!found_debug_info_section) { + 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 uint8_t *debuglink_contents = + GetOffset<ElfClass, uint8_t>(elf_header, + gnu_debuglink_section->sh_offset); + string debuglink_file = + ReadDebugLink(debuglink_contents, + gnu_debuglink_section->sh_size, + big_endian, + 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 { + // Return true if some usable information was found, since the caller + // doesn't want to use .gnu_debuglink. + return found_usable_info; + } + + // No debug info was found, let the user try again with .gnu_debuglink + // if present. + return false; + } + + 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_AARCH64: return "arm64"; + 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; + } +} + +// 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 SanitizeDebugFile(const typename ElfClass::Ehdr* debug_elf_header, + const string& debuglink_file, + const string& obj_filename, + const char* obj_file_architecture, + const bool obj_file_is_big_endian) { + 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(obj_file_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(), obj_file_architecture); + return false; + } + bool debug_big_endian; + if (!ElfEndianness<ElfClass>(debug_elf_header, &debug_big_endian)) + return false; + if (debug_big_endian != obj_file_is_big_endian) { + fprintf(stderr, "%s and %s does not match in endianness\n", + obj_filename.c_str(), debuglink_file.c_str()); + return false; + } + return true; +} + +template<typename ElfClass> +bool InitModuleForElfClass(const typename ElfClass::Ehdr* elf_header, + const string& obj_filename, + scoped_ptr<Module>& module) { + PageAllocator allocator; + wasteful_vector<uint8_t> identifier(&allocator, kDefaultBuildIdSize); + if (!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; + } + + string name = BaseFileName(obj_filename); + string os = "Linux"; + // Add an extra "0" at 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. + string id = FileID::ConvertIdentifierToUUIDString(identifier) + "0"; + // This is just the raw Build ID in hex. + string code_id = FileID::ConvertIdentifierToString(identifier); + + module.reset(new Module(name, os, architecture, id, code_id)); + + return true; +} + +template<typename ElfClass> +bool ReadSymbolDataElfClass(const typename ElfClass::Ehdr* elf_header, + const string& obj_filename, + const std::vector<string>& debug_dirs, + const DumpOptions& options, + Module** out_module) { + typedef typename ElfClass::Ehdr Ehdr; + + *out_module = NULL; + + scoped_ptr<Module> module; + if (!InitModuleForElfClass<ElfClass>(elf_header, obj_filename, module)) { + return false; + } + + // Figure out what endianness this file is. + bool big_endian; + if (!ElfEndianness<ElfClass>(elf_header, &big_endian)) + return false; + + LoadSymbolsInfo<ElfClass> info(debug_dirs); + if (!LoadSymbols<ElfClass>(obj_filename, big_endian, elf_header, + !debug_dirs.empty(), &info, + options, 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)) || + !SanitizeDebugFile<ElfClass>(debug_elf_header, debuglink_file, + obj_filename, + module->architecture().c_str(), + big_endian)) { + return false; + } + + if (!LoadSymbols<ElfClass>(debuglink_file, big_endian, + debug_elf_header, false, &info, + options, 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, + const DumpOptions& options, + 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, + options, module); + } + if (elfclass == ELFCLASS64) { + return ReadSymbolDataElfClass<ElfClass64>( + reinterpret_cast<const Elf64_Ehdr*>(obj_file), obj_filename, debug_dirs, + options, module); + } + + return false; +} + +bool WriteSymbolFile(const string &obj_file, + const std::vector<string>& debug_dirs, + const DumpOptions& options, + std::ostream &sym_stream) { + Module* module; + if (!ReadSymbolData(obj_file, debug_dirs, options, &module)) + return false; + + bool result = module->Write(sym_stream, options.symbol_data); + delete module; + return result; +} + +// Read the selected object file's debugging information, and write out the +// header only to |stream|. Return true on success; if an error occurs, report +// it and return false. +bool WriteSymbolFileHeader(const string& obj_file, + std::ostream &sym_stream) { + MmapWrapper map_wrapper; + void* elf_header = NULL; + if (!LoadELF(obj_file, &map_wrapper, &elf_header)) { + fprintf(stderr, "Could not load ELF file: %s\n", obj_file.c_str()); + return false; + } + + if (!IsValidElf(elf_header)) { + fprintf(stderr, "Not a valid ELF file: %s\n", obj_file.c_str()); + return false; + } + + int elfclass = ElfClass(elf_header); + scoped_ptr<Module> module; + if (elfclass == ELFCLASS32) { + if (!InitModuleForElfClass<ElfClass32>( + reinterpret_cast<const Elf32_Ehdr*>(elf_header), obj_file, module)) { + fprintf(stderr, "Failed to load ELF module: %s\n", obj_file.c_str()); + return false; + } + } else if (elfclass == ELFCLASS64) { + if (!InitModuleForElfClass<ElfClass64>( + reinterpret_cast<const Elf64_Ehdr*>(elf_header), obj_file, module)) { + fprintf(stderr, "Failed to load ELF module: %s\n", obj_file.c_str()); + return false; + } + } else { + fprintf(stderr, "Unsupported module file: %s\n", obj_file.c_str()); + return false; + } + + return module->Write(sym_stream, ALL_SYMBOL_DATA); +} + +bool ReadSymbolData(const string& obj_file, + const std::vector<string>& debug_dirs, + const DumpOptions& options, + 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, options, module); +} + +} // namespace google_breakpad |