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Rework dump_symbols.cc using templates and traits classes to handle cross-word-size symbol dumping

Browse source 
R=mark at https://breakpad.appspot.com/393002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@987 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
ted.mielczarek 2012-07-18 17:55:08 +00:00
parent 972be40f1f
commit 4116671cbf
5 changed files with 370 additions and 252 deletions
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404
src/common/linux/dump_symbols.cc
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@ -57,6 +57,8 @@
#include "common/dwarf_cfi_to_module.h" #include "common/dwarf_cfi_to_module.h"
#include "common/dwarf_cu_to_module.h" #include "common/dwarf_cu_to_module.h"
#include "common/dwarf_line_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/elf_symbols_to_module.h"
#include "common/linux/file_id.h" #include "common/linux/file_id.h"
#include "common/module.h" #include "common/module.h"
@ -70,6 +72,12 @@ namespace {
using google_breakpad::DwarfCFIToModule; using google_breakpad::DwarfCFIToModule;
using google_breakpad::DwarfCUToModule; using google_breakpad::DwarfCUToModule;
using google_breakpad::DwarfLineToModule; 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; using google_breakpad::Module;
using google_breakpad::StabsToModule; using google_breakpad::StabsToModule;
@ -130,24 +138,15 @@ class MmapWrapper {
size_t size_; size_t size_;
}; };
// Fix offset into virtual address by adding the mapped base into offsets.
// Make life easier when want to find something by offset.
static void FixAddress(void *obj_base) {
ElfW(Addr) base = reinterpret_cast<ElfW(Addr)>(obj_base);
ElfW(Ehdr) *elf_header = static_cast<ElfW(Ehdr) *>(obj_base);
elf_header->e_phoff += base;
elf_header->e_shoff += base;
ElfW(Shdr) *sections = reinterpret_cast<ElfW(Shdr) *>(elf_header->e_shoff);
for (int i = 0; i < elf_header->e_shnum; ++i)
sections[i].sh_offset += base;
}
// Find the preferred loading address of the binary. // Find the preferred loading address of the binary.
static ElfW(Addr) GetLoadingAddress(const ElfW(Phdr) *program_headers, template<typename ElfClass>
typename ElfClass::Addr GetLoadingAddress(
const typename ElfClass::Phdr* program_headers,
int nheader) { int nheader) {
typedef typename ElfClass::Phdr Phdr;
for (int i = 0; i < nheader; ++i) { for (int i = 0; i < nheader; ++i) {
const ElfW(Phdr) &header = program_headers[i]; const Phdr& header = program_headers[i];
// For executable, it is the PT_LOAD segment with offset to zero. // For executable, it is the PT_LOAD segment with offset to zero.
if (header.p_type == PT_LOAD && if (header.p_type == PT_LOAD &&
header.p_offset == 0) header.p_offset == 0)
@ -157,57 +156,22 @@ static ElfW(Addr) GetLoadingAddress(const ElfW(Phdr) *program_headers,
return 0; return 0;
} }
static bool IsValidElf(const ElfW(Ehdr) *elf_header) { template<typename ElfClass>
return memcmp(elf_header, ELFMAG, SELFMAG) == 0; bool LoadStabs(const typename ElfClass::Ehdr* elf_header,
} const typename ElfClass::Shdr* stab_section,
const typename ElfClass::Shdr* stabstr_section,
static const ElfW(Shdr) *FindSectionByName(const char *name,
const ElfW(Shdr) *sections,
const ElfW(Shdr) *section_names,
int nsection) {
assert(name != NULL);
assert(sections != NULL);
assert(nsection > 0);
int name_len = strlen(name);
if (name_len == 0)
return NULL;
// Find the end of the section name section, to make sure that
// comparisons don't run off the end of the section.
const char *names_end =
reinterpret_cast<char*>(section_names->sh_offset + section_names->sh_size);
for (int i = 0; i < nsection; ++i) {
const char *section_name =
reinterpret_cast<char*>(section_names->sh_offset + sections[i].sh_name);
if (names_end - section_name >= name_len + 1 &&
strcmp(name, section_name) == 0) {
if (sections[i].sh_type == SHT_NOBITS) {
fprintf(stderr,
"Section %s found, but ignored because type=SHT_NOBITS.\n",
name);
return NULL;
}
return sections + i;
}
}
return NULL;
}
static bool LoadStabs(const ElfW(Ehdr) *elf_header,
const ElfW(Shdr) *stab_section,
const ElfW(Shdr) *stabstr_section,
const bool big_endian, const bool big_endian,
Module *module) { Module* module) {
// A callback object to handle data from the STABS reader. // A callback object to handle data from the STABS reader.
StabsToModule handler(module); StabsToModule handler(module);
// Find the addresses of the STABS data, and create a STABS reader object. // 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 // On Linux, STABS entries always have 32-bit values, regardless of the
// address size of the architecture whose code they're describing, and // address size of the architecture whose code they're describing, and
// the strings are always "unitized". // the strings are always "unitized".
uint8_t *stabs = reinterpret_cast<uint8_t *>(stab_section->sh_offset); const uint8_t* stabs =
uint8_t *stabstr = reinterpret_cast<uint8_t *>(stabstr_section->sh_offset); 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, google_breakpad::StabsReader reader(stabs, stab_section->sh_size,
stabstr, stabstr_section->sh_size, stabstr, stabstr_section->sh_size,
big_endian, 4, true, &handler); big_endian, 4, true, &handler);
@ -236,10 +200,13 @@ class DumperLineToModule: public DwarfCUToModule::LineToModuleFunctor {
dwarf2reader::ByteReader *byte_reader_; dwarf2reader::ByteReader *byte_reader_;
}; };
static bool LoadDwarf(const string &dwarf_filename, template<typename ElfClass>
const ElfW(Ehdr) *elf_header, bool LoadDwarf(const string& dwarf_filename,
const typename ElfClass::Ehdr* elf_header,
const bool big_endian, const bool big_endian,
Module *module) { Module* module) {
typedef typename ElfClass::Shdr Shdr;
const dwarf2reader::Endianness endianness = big_endian ? const dwarf2reader::Endianness endianness = big_endian ?
dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE; dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE;
dwarf2reader::ByteReader byte_reader(endianness); dwarf2reader::ByteReader byte_reader(endianness);
@ -248,15 +215,17 @@ static bool LoadDwarf(const string &dwarf_filename,
DwarfCUToModule::FileContext file_context(dwarf_filename, module); DwarfCUToModule::FileContext file_context(dwarf_filename, module);
// Build a map of the ELF file's sections. // Build a map of the ELF file's sections.
const ElfW(Shdr) *sections const Shdr* sections =
= reinterpret_cast<ElfW(Shdr) *>(elf_header->e_shoff); GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
int num_sections = elf_header->e_shnum; int num_sections = elf_header->e_shnum;
const ElfW(Shdr) *section_names = sections + elf_header->e_shstrndx; const Shdr* section_names = sections + elf_header->e_shstrndx;
for (int i = 0; i < num_sections; i++) { for (int i = 0; i < num_sections; i++) {
const ElfW(Shdr) *section = &sections[i]; const Shdr* section = &sections[i];
string name = reinterpret_cast<const char *>(section_names->sh_offset + string name = GetOffset<ElfClass, char>(elf_header,
section->sh_name); section_names->sh_offset) +
const char *contents = reinterpret_cast<const char *>(section->sh_offset); section->sh_name;
const char* contents = GetOffset<ElfClass, char>(elf_header,
section->sh_offset);
uint64 length = section->sh_size; uint64 length = section->sh_size;
file_context.section_map[name] = std::make_pair(contents, length); file_context.section_map[name] = std::make_pair(contents, length);
} }
@ -265,16 +234,16 @@ static bool LoadDwarf(const string &dwarf_filename,
DumperLineToModule line_to_module(&byte_reader); DumperLineToModule line_to_module(&byte_reader);
std::pair<const char *, uint64> debug_info_section std::pair<const char *, uint64> debug_info_section
= file_context.section_map[".debug_info"]; = file_context.section_map[".debug_info"];
// We should never have been called if the file doesn't have a // This should never have been called if the file doesn't have a
// .debug_info section. // .debug_info section.
assert(debug_info_section.first); assert(debug_info_section.first);
uint64 debug_info_length = debug_info_section.second; uint64 debug_info_length = debug_info_section.second;
for (uint64 offset = 0; offset < debug_info_length;) { for (uint64 offset = 0; offset < debug_info_length;) {
// Make a handler for the root DIE that populates MODULE with the // Make a handler for the root DIE that populates MODULE with the
// data we find. // data that was found.
DwarfCUToModule::WarningReporter reporter(dwarf_filename, offset); DwarfCUToModule::WarningReporter reporter(dwarf_filename, offset);
DwarfCUToModule root_handler(&file_context, &line_to_module, &reporter); DwarfCUToModule root_handler(&file_context, &line_to_module, &reporter);
// Make a Dwarf2Handler that drives our DIEHandler. // Make a Dwarf2Handler that drives the DIEHandler.
dwarf2reader::DIEDispatcher die_dispatcher(&root_handler); dwarf2reader::DIEDispatcher die_dispatcher(&root_handler);
// Make a DWARF parser for the compilation unit at OFFSET. // Make a DWARF parser for the compilation unit at OFFSET.
dwarf2reader::CompilationUnit reader(file_context.section_map, dwarf2reader::CompilationUnit reader(file_context.section_map,
@ -290,10 +259,11 @@ static bool LoadDwarf(const string &dwarf_filename,
// Fill REGISTER_NAMES with the register names appropriate to the // Fill REGISTER_NAMES with the register names appropriate to the
// machine architecture given in HEADER, indexed by the register // machine architecture given in HEADER, indexed by the register
// numbers used in DWARF call frame information. Return true on // numbers used in DWARF call frame information. Return true on
// success, or false if we don't recognize HEADER's machine // success, or false if HEADER's machine architecture is not
// architecture. // supported.
static bool DwarfCFIRegisterNames(const ElfW(Ehdr) *elf_header, template<typename ElfClass>
std::vector<string> *register_names) { bool DwarfCFIRegisterNames(const typename ElfClass::Ehdr* elf_header,
std::vector<string>* register_names) {
switch (elf_header->e_machine) { switch (elf_header->e_machine) {
case EM_386: case EM_386:
*register_names = DwarfCFIToModule::RegisterNames::I386(); *register_names = DwarfCFIToModule::RegisterNames::I386();
@ -309,19 +279,20 @@ static bool DwarfCFIRegisterNames(const ElfW(Ehdr) *elf_header,
} }
} }
static bool LoadDwarfCFI(const string &dwarf_filename, template<typename ElfClass>
const ElfW(Ehdr) *elf_header, bool LoadDwarfCFI(const string& dwarf_filename,
const char *section_name, const typename ElfClass::Ehdr* elf_header,
const ElfW(Shdr) *section, const char* section_name,
const typename ElfClass::Shdr* section,
const bool eh_frame, const bool eh_frame,
const ElfW(Shdr) *got_section, const typename ElfClass::Shdr* got_section,
const ElfW(Shdr) *text_section, const typename ElfClass::Shdr* text_section,
const bool big_endian, const bool big_endian,
Module *module) { Module* module) {
// Find the appropriate set of register names for this file's // Find the appropriate set of register names for this file's
// architecture. // architecture.
std::vector<string> register_names; std::vector<string> register_names;
if (!DwarfCFIRegisterNames(elf_header, &register_names)) { if (!DwarfCFIRegisterNames<ElfClass>(elf_header, &register_names)) {
fprintf(stderr, "%s: unrecognized ELF machine architecture '%d';" fprintf(stderr, "%s: unrecognized ELF machine architecture '%d';"
" cannot convert DWARF call frame information\n", " cannot convert DWARF call frame information\n",
dwarf_filename.c_str(), elf_header->e_machine); dwarf_filename.c_str(), elf_header->e_machine);
@ -332,25 +303,17 @@ static bool LoadDwarfCFI(const string &dwarf_filename,
dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE; dwarf2reader::ENDIANNESS_BIG : dwarf2reader::ENDIANNESS_LITTLE;
// Find the call frame information and its size. // Find the call frame information and its size.
const char *cfi = reinterpret_cast<const char *>(section->sh_offset); const char* cfi =
GetOffset<ElfClass, char>(elf_header, section->sh_offset);
size_t cfi_size = section->sh_size; size_t cfi_size = section->sh_size;
// Plug together the parser, handler, and their entourages. // Plug together the parser, handler, and their entourages.
DwarfCFIToModule::Reporter module_reporter(dwarf_filename, section_name); DwarfCFIToModule::Reporter module_reporter(dwarf_filename, section_name);
DwarfCFIToModule handler(module, register_names, &module_reporter); DwarfCFIToModule handler(module, register_names, &module_reporter);
dwarf2reader::ByteReader byte_reader(endianness); dwarf2reader::ByteReader byte_reader(endianness);
// Since we're using the ElfW macro, we're not actually capable of
// processing both ELF32 and ELF64 files with the same program; that byte_reader.SetAddressSize(ElfClass::kAddrSize);
// would take a bit more work. But this will work out well enough.
if (elf_header->e_ident[EI_CLASS] == ELFCLASS32)
byte_reader.SetAddressSize(4);
else if (elf_header->e_ident[EI_CLASS] == ELFCLASS64)
byte_reader.SetAddressSize(8);
else {
fprintf(stderr, "%s: bad file class in ELF header: %d\n",
dwarf_filename.c_str(), elf_header->e_ident[EI_CLASS]);
return false;
}
// Provide the base addresses for .eh_frame encoded pointers, if // Provide the base addresses for .eh_frame encoded pointers, if
// possible. // possible.
byte_reader.SetCFIDataBase(section->sh_addr, cfi); byte_reader.SetCFIDataBase(section->sh_addr, cfi);
@ -368,8 +331,8 @@ static bool LoadDwarfCFI(const string &dwarf_filename,
return true; return true;
} }
bool LoadELF(const string &obj_file, MmapWrapper* map_wrapper, bool LoadELF(const string& obj_file, MmapWrapper* map_wrapper,
ElfW(Ehdr) **elf_header) { void** elf_header) {
int obj_fd = open(obj_file.c_str(), O_RDONLY); int obj_fd = open(obj_file.c_str(), O_RDONLY);
if (obj_fd < 0) { if (obj_fd < 0) {
fprintf(stderr, "Failed to open ELF file '%s': %s\n", fprintf(stderr, "Failed to open ELF file '%s': %s\n",
@ -391,7 +354,7 @@ bool LoadELF(const string &obj_file, MmapWrapper* map_wrapper,
return false; return false;
} }
map_wrapper->set(obj_base, st.st_size); map_wrapper->set(obj_base, st.st_size);
*elf_header = reinterpret_cast<ElfW(Ehdr) *>(obj_base); *elf_header = obj_base;
if (!IsValidElf(*elf_header)) { if (!IsValidElf(*elf_header)) {
fprintf(stderr, "Not a valid ELF file: %s\n", obj_file.c_str()); fprintf(stderr, "Not a valid ELF file: %s\n", obj_file.c_str());
return false; return false;
@ -400,7 +363,9 @@ bool LoadELF(const string &obj_file, MmapWrapper* map_wrapper,
} }
// Get the endianness of ELF_HEADER. If it's invalid, return false. // Get the endianness of ELF_HEADER. If it's invalid, return false.
bool ElfEndianness(const ElfW(Ehdr) *elf_header, bool *big_endian) { template<typename ElfClass>
bool ElfEndianness(const typename ElfClass::Ehdr* elf_header,
bool* big_endian) {
if (elf_header->e_ident[EI_DATA] == ELFDATA2LSB) { if (elf_header->e_ident[EI_DATA] == ELFDATA2LSB) {
*big_endian = false; *big_endian = false;
return true; return true;
@ -417,17 +382,18 @@ bool ElfEndianness(const ElfW(Ehdr) *elf_header, bool *big_endian) {
// Read the .gnu_debuglink and get the debug file name. If anything goes // Read the .gnu_debuglink and get the debug file name. If anything goes
// wrong, return an empty string. // wrong, return an empty string.
static string ReadDebugLink(const ElfW(Shdr) *debuglink_section, template<typename ElfClass>
const string &obj_file, string ReadDebugLink(const char* debuglink,
const string &debug_dir) { size_t debuglink_size,
char *debuglink = reinterpret_cast<char *>(debuglink_section->sh_offset); const string& obj_file,
const string& debug_dir) {
size_t debuglink_len = strlen(debuglink) + 5; // '\0' + CRC32. size_t debuglink_len = strlen(debuglink) + 5; // '\0' + CRC32.
debuglink_len = 4 * ((debuglink_len + 3) / 4); // Round to nearest 4 bytes. debuglink_len = 4 * ((debuglink_len + 3) / 4); // Round to nearest 4 bytes.
// Sanity check. // Sanity check.
if (debuglink_len != debuglink_section->sh_size) { if (debuglink_len != debuglink_size) {
fprintf(stderr, "Mismatched .gnu_debuglink string / section size: " fprintf(stderr, "Mismatched .gnu_debuglink string / section size: "
"%zx %zx\n", debuglink_len, debuglink_section->sh_size); "%zx %zx\n", debuglink_len, debuglink_size);
return ""; return "";
} }
@ -448,18 +414,21 @@ static string ReadDebugLink(const ElfW(Shdr) *debuglink_section,
// //
// LoadSymbolsInfo // LoadSymbolsInfo
// //
// Holds the state between the two calls to LoadSymbols() in case we have to // Holds the state between the two calls to LoadSymbols() in case it's necessary
// follow the .gnu_debuglink section and load debug information from a // to follow the .gnu_debuglink section and load debug information from a
// different file. // different file.
// //
template<typename ElfClass>
class LoadSymbolsInfo { class LoadSymbolsInfo {
public: public:
typedef typename ElfClass::Addr Addr;
explicit LoadSymbolsInfo(const string &dbg_dir) : explicit LoadSymbolsInfo(const string &dbg_dir) :
debug_dir_(dbg_dir), debug_dir_(dbg_dir),
has_loading_addr_(false) {} has_loading_addr_(false) {}
// Keeps track of which sections have been loaded so we don't accidentally // Keeps track of which sections have been loaded so sections don't
// load it twice from two different files. // accidentally get loaded twice from two different files.
void LoadedSection(const string &section) { void LoadedSection(const string &section) {
if (loaded_sections_.count(section) == 0) { if (loaded_sections_.count(section) == 0) {
loaded_sections_.insert(section); loaded_sections_.insert(section);
@ -469,9 +438,9 @@ class LoadSymbolsInfo {
} }
} }
// We expect the ELF file and linked debug file to have the same preferred // The ELF file and linked debug file are expected to have the same preferred
// loading address. // loading address.
void set_loading_addr(ElfW(Addr) addr, const string &filename) { void set_loading_addr(Addr addr, const string &filename) {
if (!has_loading_addr_) { if (!has_loading_addr_) {
loading_addr_ = addr; loading_addr_ = addr;
loaded_file_ = filename; loaded_file_ = filename;
@ -506,7 +475,7 @@ class LoadSymbolsInfo {
bool has_loading_addr_; // Indicate if LOADING_ADDR_ is valid. bool has_loading_addr_; // Indicate if LOADING_ADDR_ is valid.
ElfW(Addr) loading_addr_; // Saves the preferred loading address from the Addr loading_addr_; // Saves the preferred loading address from the
// first call to LoadSymbols(). // first call to LoadSymbols().
string loaded_file_; // Name of the file loaded from the first call to string loaded_file_; // Name of the file loaded from the first call to
@ -516,38 +485,45 @@ class LoadSymbolsInfo {
// between calls to LoadSymbols(). // between calls to LoadSymbols().
}; };
static bool LoadSymbols(const string &obj_file, template<typename ElfClass>
bool LoadSymbols(const string& obj_file,
const bool big_endian, const bool big_endian,
ElfW(Ehdr) *elf_header, const typename ElfClass::Ehdr* elf_header,
const bool read_gnu_debug_link, const bool read_gnu_debug_link,
LoadSymbolsInfo *info, LoadSymbolsInfo<ElfClass>* info,
Module *module) { Module* module) {
// Translate all offsets in section headers into address. typedef typename ElfClass::Addr Addr;
FixAddress(elf_header); typedef typename ElfClass::Phdr Phdr;
ElfW(Addr) loading_addr = GetLoadingAddress( typedef typename ElfClass::Shdr Shdr;
reinterpret_cast<ElfW(Phdr) *>(elf_header->e_phoff),
Addr loading_addr = GetLoadingAddress<ElfClass>(
GetOffset<ElfClass, Phdr>(elf_header, elf_header->e_phoff),
elf_header->e_phnum); elf_header->e_phnum);
module->SetLoadAddress(loading_addr); module->SetLoadAddress(loading_addr);
info->set_loading_addr(loading_addr, obj_file); info->set_loading_addr(loading_addr, obj_file);
const ElfW(Shdr) *sections = const Shdr* sections =
reinterpret_cast<ElfW(Shdr) *>(elf_header->e_shoff); GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
const ElfW(Shdr) *section_names = sections + elf_header->e_shstrndx; 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_debug_info_section = false;
bool found_usable_info = false; bool found_usable_info = false;
// Look for STABS debugging information, and load it if present. // Look for STABS debugging information, and load it if present.
const ElfW(Shdr) *stab_section const Shdr* stab_section =
= FindSectionByName(".stab", sections, section_names, FindElfSectionByName<ElfClass>(".stab", SHT_PROGBITS,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
if (stab_section) { if (stab_section) {
const ElfW(Shdr) *stabstr_section = stab_section->sh_link + sections; const Shdr* stabstr_section = stab_section->sh_link + sections;
if (stabstr_section) { if (stabstr_section) {
found_debug_info_section = true; found_debug_info_section = true;
found_usable_info = true; found_usable_info = true;
info->LoadedSection(".stab"); info->LoadedSection(".stab");
if (!LoadStabs(elf_header, stab_section, stabstr_section, big_endian, if (!LoadStabs<ElfClass>(elf_header, stab_section, stabstr_section,
module)) { big_endian, module)) {
fprintf(stderr, "%s: \".stab\" section found, but failed to load STABS" fprintf(stderr, "%s: \".stab\" section found, but failed to load STABS"
" debugging information\n", obj_file.c_str()); " debugging information\n", obj_file.c_str());
} }
@ -555,22 +531,24 @@ static bool LoadSymbols(const string &obj_file,
} }
// Look for DWARF debugging information, and load it if present. // Look for DWARF debugging information, and load it if present.
const ElfW(Shdr) *dwarf_section const Shdr* dwarf_section =
= FindSectionByName(".debug_info", sections, section_names, FindElfSectionByName<ElfClass>(".debug_info", SHT_PROGBITS,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
if (dwarf_section) { if (dwarf_section) {
found_debug_info_section = true; found_debug_info_section = true;
found_usable_info = true; found_usable_info = true;
info->LoadedSection(".debug_info"); info->LoadedSection(".debug_info");
if (!LoadDwarf(obj_file, elf_header, big_endian, module)) if (!LoadDwarf<ElfClass>(obj_file, elf_header, big_endian, module))
fprintf(stderr, "%s: \".debug_info\" section found, but failed to load " fprintf(stderr, "%s: \".debug_info\" section found, but failed to load "
"DWARF debugging information\n", obj_file.c_str()); "DWARF debugging information\n", obj_file.c_str());
} }
// Dwarf Call Frame Information (CFI) is actually independent from // Dwarf Call Frame Information (CFI) is actually independent from
// the other DWARF debugging information, and can be used alone. // the other DWARF debugging information, and can be used alone.
const ElfW(Shdr) *dwarf_cfi_section = const Shdr* dwarf_cfi_section =
FindSectionByName(".debug_frame", sections, section_names, FindElfSectionByName<ElfClass>(".debug_frame", SHT_PROGBITS,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
if (dwarf_cfi_section) { if (dwarf_cfi_section) {
// Ignore the return value of this function; even without call frame // Ignore the return value of this function; even without call frame
@ -578,28 +556,34 @@ static bool LoadSymbols(const string &obj_file,
// useful. // useful.
info->LoadedSection(".debug_frame"); info->LoadedSection(".debug_frame");
bool result = bool result =
LoadDwarfCFI(obj_file, elf_header, ".debug_frame", LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".debug_frame",
dwarf_cfi_section, false, 0, 0, big_endian, module); dwarf_cfi_section, false, 0, 0, big_endian,
module);
found_usable_info = found_usable_info || result; found_usable_info = found_usable_info || result;
} }
// Linux C++ exception handling information can also provide // Linux C++ exception handling information can also provide
// unwinding data. // unwinding data.
const ElfW(Shdr) *eh_frame_section = const Shdr* eh_frame_section =
FindSectionByName(".eh_frame", sections, section_names, FindElfSectionByName<ElfClass>(".eh_frame", SHT_PROGBITS,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
if (eh_frame_section) { if (eh_frame_section) {
// Pointers in .eh_frame data may be relative to the base addresses of // Pointers in .eh_frame data may be relative to the base addresses of
// certain sections. Provide those sections if present. // certain sections. Provide those sections if present.
const ElfW(Shdr) *got_section = const Shdr* got_section =
FindSectionByName(".got", sections, section_names, elf_header->e_shnum); FindElfSectionByName<ElfClass>(".got", SHT_PROGBITS,
const ElfW(Shdr) *text_section = sections, names, names_end,
FindSectionByName(".text", sections, section_names, elf_header->e_shnum);
const Shdr* text_section =
FindElfSectionByName<ElfClass>(".text", SHT_PROGBITS,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
info->LoadedSection(".eh_frame"); info->LoadedSection(".eh_frame");
// As above, ignore the return value of this function. // As above, ignore the return value of this function.
bool result = bool result =
LoadDwarfCFI(obj_file, elf_header, ".eh_frame", eh_frame_section, true, LoadDwarfCFI<ElfClass>(obj_file, elf_header, ".eh_frame",
eh_frame_section, true,
got_section, text_section, big_endian, module); got_section, text_section, big_endian, module);
found_usable_info = found_usable_info || result; found_usable_info = found_usable_info || result;
} }
@ -609,15 +593,21 @@ static bool LoadSymbols(const string &obj_file,
" (no \".stab\" or \".debug_info\" sections)\n", " (no \".stab\" or \".debug_info\" sections)\n",
obj_file.c_str()); obj_file.c_str());
// Failed, but maybe we can find a .gnu_debuglink section? // Failed, but maybe there's a .gnu_debuglink section?
if (read_gnu_debug_link) { if (read_gnu_debug_link) {
const ElfW(Shdr) *gnu_debuglink_section const Shdr* gnu_debuglink_section
= FindSectionByName(".gnu_debuglink", sections, section_names, = FindElfSectionByName<ElfClass>(".gnu_debuglink", SHT_PROGBITS,
elf_header->e_shnum); sections, names,
names_end, elf_header->e_shnum);
if (gnu_debuglink_section) { if (gnu_debuglink_section) {
if (!info->debug_dir().empty()) { if (!info->debug_dir().empty()) {
string debuglink_file = const char* debuglink_contents =
ReadDebugLink(gnu_debuglink_section, obj_file, info->debug_dir()); 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_dir());
info->set_debuglink_file(debuglink_file); info->set_debuglink_file(debuglink_file);
} else { } else {
fprintf(stderr, ".gnu_debuglink section found in '%s', " fprintf(stderr, ".gnu_debuglink section found in '%s', "
@ -630,30 +620,28 @@ static bool LoadSymbols(const string &obj_file,
} else { } else {
// The caller doesn't want to consult .gnu_debuglink. // The caller doesn't want to consult .gnu_debuglink.
// See if there are export symbols available. // See if there are export symbols available.
const ElfW(Shdr) *dynsym_section = const Shdr* dynsym_section =
FindSectionByName(".dynsym", sections, section_names, FindElfSectionByName<ElfClass>(".dynsym", SHT_DYNSYM,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
const ElfW(Shdr) *dynstr_section = const Shdr* dynstr_section =
FindSectionByName(".dynstr", sections, section_names, FindElfSectionByName<ElfClass>(".dynstr", SHT_STRTAB,
sections, names, names_end,
elf_header->e_shnum); elf_header->e_shnum);
if (dynsym_section && dynstr_section) { if (dynsym_section && dynstr_section) {
info->LoadedSection(".dynsym"); info->LoadedSection(".dynsym");
fprintf(stderr, "Have .dynsym + .dynstr\n");
uint8_t* dynsyms = const uint8_t* dynsyms =
reinterpret_cast<uint8_t*>(dynsym_section->sh_offset); GetOffset<ElfClass, uint8_t>(elf_header, dynsym_section->sh_offset);
uint8_t* dynstrs = const uint8_t* dynstrs =
reinterpret_cast<uint8_t*>(dynstr_section->sh_offset); GetOffset<ElfClass, uint8_t>(elf_header, dynstr_section->sh_offset);
bool result = bool result =
ELFSymbolsToModule(dynsyms, ELFSymbolsToModule(dynsyms,
dynsym_section->sh_size, dynsym_section->sh_size,
dynstrs, dynstrs,
dynstr_section->sh_size, dynstr_section->sh_size,
big_endian, big_endian,
// This could change to something more useful ElfClass::kAddrSize,
// when support for dumping cross-architecture
// symbols is finished.
sizeof(ElfW(Addr)),
module); module);
found_usable_info = found_usable_info || result; found_usable_info = found_usable_info || result;
} }
@ -673,8 +661,10 @@ static bool LoadSymbols(const string &obj_file,
// Return the breakpad symbol file identifier for the architecture of // Return the breakpad symbol file identifier for the architecture of
// ELF_HEADER. // ELF_HEADER.
const char *ElfArchitecture(const ElfW(Ehdr) *elf_header) { template<typename ElfClass>
ElfW(Half) arch = elf_header->e_machine; const char* ElfArchitecture(const typename ElfClass::Ehdr* elf_header) {
typedef typename ElfClass::Half Half;
Half arch = elf_header->e_machine;
switch (arch) { switch (arch) {
case EM_386: return "x86"; case EM_386: return "x86";
case EM_ARM: return "arm"; case EM_ARM: return "arm";
@ -703,8 +693,7 @@ string FormatIdentifier(unsigned char identifier[16]) {
id_no_dash += identifier_str[i]; id_no_dash += identifier_str[i];
// Add an extra "0" by the end. PDB files on Windows have an 'age' // 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 // number appended to the end of the file identifier; this isn't
// really used or necessary on other platforms, but let's preserve // really used or necessary on other platforms, but be consistent.
// the pattern.
id_no_dash += '0'; id_no_dash += '0';
return id_no_dash; return id_no_dash;
} }
@ -719,24 +708,14 @@ string BaseFileName(const string &filename) {
return base; return base;
} }
} // namespace template<typename ElfClass>
bool WriteSymbolFileElfClass(const typename ElfClass::Ehdr* elf_header,
namespace google_breakpad { const string& obj_filename,
const string& debug_dir,
// Not explicitly exported, but not static so it can be used in unit tests.
// Ideally obj_file would be const, but internally this code does write
// to some ELF header fields to make its work simpler.
bool WriteSymbolFileInternal(uint8_t* obj_file,
const string &obj_filename,
const string &debug_dir,
bool cfi, bool cfi,
std::ostream &sym_stream) { std::ostream& sym_stream) {
ElfW(Ehdr) *elf_header = reinterpret_cast<ElfW(Ehdr) *>(obj_file); typedef typename ElfClass::Ehdr Ehdr;
typedef typename ElfClass::Shdr Shdr;
if (!IsValidElf(elf_header)) {
fprintf(stderr, "Not a valid ELF file: %s\n", obj_filename.c_str());
return false;
}
unsigned char identifier[16]; unsigned char identifier[16];
if (!google_breakpad::FileID::ElfFileIdentifierFromMappedFile(elf_header, if (!google_breakpad::FileID::ElfFileIdentifierFromMappedFile(elf_header,
@ -746,7 +725,7 @@ bool WriteSymbolFileInternal(uint8_t* obj_file,
return false; return false;
} }
const char *architecture = ElfArchitecture(elf_header); const char *architecture = ElfArchitecture<ElfClass>(elf_header);
if (!architecture) { if (!architecture) {
fprintf(stderr, "%s: unrecognized ELF machine architecture: %d\n", fprintf(stderr, "%s: unrecognized ELF machine architecture: %d\n",
obj_filename.c_str(), elf_header->e_machine); obj_filename.c_str(), elf_header->e_machine);
@ -755,17 +734,17 @@ bool WriteSymbolFileInternal(uint8_t* obj_file,
// Figure out what endianness this file is. // Figure out what endianness this file is.
bool big_endian; bool big_endian;
if (!ElfEndianness(elf_header, &big_endian)) if (!ElfEndianness<ElfClass>(elf_header, &big_endian))
return false; return false;
string name = BaseFileName(obj_filename); string name = BaseFileName(obj_filename);
string os = "Linux"; string os = "Linux";
string id = FormatIdentifier(identifier); string id = FormatIdentifier(identifier);
LoadSymbolsInfo info(debug_dir); LoadSymbolsInfo<ElfClass> info(debug_dir);
Module module(name, os, architecture, id); Module module(name, os, architecture, id);
if (!LoadSymbols(obj_filename, big_endian, elf_header, !debug_dir.empty(), if (!LoadSymbols<ElfClass>(obj_filename, big_endian, elf_header,
&info, &module)) { !debug_dir.empty(), &info, &module)) {
const string debuglink_file = info.debuglink_file(); const string debuglink_file = info.debuglink_file();
if (debuglink_file.empty()) if (debuglink_file.empty())
return false; return false;
@ -773,11 +752,13 @@ bool WriteSymbolFileInternal(uint8_t* obj_file,
// Load debuglink ELF file. // Load debuglink ELF file.
fprintf(stderr, "Found debugging info in %s\n", debuglink_file.c_str()); fprintf(stderr, "Found debugging info in %s\n", debuglink_file.c_str());
MmapWrapper debug_map_wrapper; MmapWrapper debug_map_wrapper;
ElfW(Ehdr) *debug_elf_header = NULL; Ehdr* debug_elf_header = NULL;
if (!LoadELF(debuglink_file, &debug_map_wrapper, &debug_elf_header)) if (!LoadELF(debuglink_file, &debug_map_wrapper,
reinterpret_cast<void**>(&debug_elf_header)))
return false; return false;
// Sanity checks to make sure everything matches up. // Sanity checks to make sure everything matches up.
const char *debug_architecture = ElfArchitecture(debug_elf_header); const char *debug_architecture =
ElfArchitecture<ElfClass>(debug_elf_header);
if (!debug_architecture) { if (!debug_architecture) {
fprintf(stderr, "%s: unrecognized ELF machine architecture: %d\n", fprintf(stderr, "%s: unrecognized ELF machine architecture: %d\n",
debuglink_file.c_str(), debug_elf_header->e_machine); debuglink_file.c_str(), debug_elf_header->e_machine);
@ -792,7 +773,7 @@ bool WriteSymbolFileInternal(uint8_t* obj_file,
} }
bool debug_big_endian; bool debug_big_endian;
if (!ElfEndianness(debug_elf_header, &debug_big_endian)) if (!ElfEndianness<ElfClass>(debug_elf_header, &debug_big_endian))
return false; return false;
if (debug_big_endian != big_endian) { if (debug_big_endian != big_endian) {
fprintf(stderr, "%s and %s does not match in endianness\n", fprintf(stderr, "%s and %s does not match in endianness\n",
@ -800,8 +781,8 @@ bool WriteSymbolFileInternal(uint8_t* obj_file,
return false; return false;
} }
if (!LoadSymbols(debuglink_file, debug_big_endian, debug_elf_header, if (!LoadSymbols<ElfClass>(debuglink_file, debug_big_endian,
false, &info, &module)) { debug_elf_header, false, &info, &module)) {
return false; return false;
} }
} }
@ -811,12 +792,43 @@ bool WriteSymbolFileInternal(uint8_t* obj_file,
return true; return true;
} }
} // namespace
namespace google_breakpad {
// Not explicitly exported, but not static so it can be used in unit tests.
bool WriteSymbolFileInternal(const uint8_t* obj_file,
const string& obj_filename,
const string& debug_dir,
bool cfi,
std::ostream& sym_stream) {
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 WriteSymbolFileElfClass<ElfClass32>(
reinterpret_cast<const Elf32_Ehdr*>(obj_file), obj_filename, debug_dir,
cfi, sym_stream);
}
if (elfclass == ELFCLASS64) {
return WriteSymbolFileElfClass<ElfClass64>(
reinterpret_cast<const Elf64_Ehdr*>(obj_file), obj_filename, debug_dir,
cfi, sym_stream);
}
return false;
}
bool WriteSymbolFile(const string &obj_file, bool WriteSymbolFile(const string &obj_file,
const string &debug_dir, const string &debug_dir,
bool cfi, bool cfi,
std::ostream &sym_stream) { std::ostream &sym_stream) {
MmapWrapper map_wrapper; MmapWrapper map_wrapper;
ElfW(Ehdr) *elf_header = NULL; void* elf_header = NULL;
if (!LoadELF(obj_file, &map_wrapper, &elf_header)) if (!LoadELF(obj_file, &map_wrapper, &elf_header))
return false; return false;

8
src/common/linux/dump_symbols_unittest.cc
View file

@ -45,7 +45,7 @@
#include "common/using_std_string.h" #include "common/using_std_string.h"
namespace google_breakpad { namespace google_breakpad {
bool WriteSymbolFileInternal(uint8_t* obj_file, bool WriteSymbolFileInternal(const uint8_t* obj_file,
const string &obj_filename, const string &obj_filename,
const string &debug_dir, const string &debug_dir,
bool cfi, bool cfi,
@ -89,9 +89,6 @@ TEST_F(DumpSymbols, Invalid) {
s)); s));
} }
// TODO(ted): Fix the dump_symbols code to deal with cross-word-size
// ELF files.
#if __ELF_NATIVE_CLASS == 32
TEST_F(DumpSymbols, SimplePublic32) { TEST_F(DumpSymbols, SimplePublic32) {
ELF elf(EM_386, ELFCLASS32, kLittleEndian); ELF elf(EM_386, ELFCLASS32, kLittleEndian);
// Zero out text section for simplicity. // Zero out text section for simplicity.
@ -126,9 +123,7 @@ TEST_F(DumpSymbols, SimplePublic32) {
"PUBLIC 1000 0 superfunc\n", "PUBLIC 1000 0 superfunc\n",
s.str()); s.str());
} }
#endif
#if __ELF_NATIVE_CLASS == 64
TEST_F(DumpSymbols, SimplePublic64) { TEST_F(DumpSymbols, SimplePublic64) {
ELF elf(EM_X86_64, ELFCLASS64, kLittleEndian); ELF elf(EM_X86_64, ELFCLASS64, kLittleEndian);
// Zero out text section for simplicity. // Zero out text section for simplicity.
@ -163,4 +158,3 @@ TEST_F(DumpSymbols, SimplePublic64) {
"PUBLIC 1000 0 superfunc\n", "PUBLIC 1000 0 superfunc\n",
s.str()); s.str());
} }
#endif

74
src/common/linux/elfutils-inl.h Normal file
View file

@ -0,0 +1,74 @@
// Copyright (c) 2012, 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.
#ifndef COMMON_LINUX_ELFUTILS_INL_H__
#define COMMON_LINUX_ELFUTILS_INL_H__
#include "common/linux/linux_libc_support.h"
#include "elfutils.h"
namespace google_breakpad {
template<typename ElfClass, typename T>
const T* GetOffset(const typename ElfClass::Ehdr* elf_header,
typename ElfClass::Off offset) {
return reinterpret_cast<const T*>(reinterpret_cast<uintptr_t>(elf_header) +
offset);
}
template<typename ElfClass>
const typename ElfClass::Shdr* FindElfSectionByName(
const char* name,
typename ElfClass::Word section_type,
const typename ElfClass::Shdr* sections,
const char* section_names,
const char* names_end,
int nsection) {
assert(name != NULL);
assert(sections != NULL);
assert(nsection > 0);
int name_len = my_strlen(name);
if (name_len == 0)
return NULL;
for (int i = 0; i < nsection; ++i) {
const char* section_name = section_names + sections[i].sh_name;
if (sections[i].sh_type == section_type &&
names_end - section_name >= name_len + 1 &&
my_strcmp(name, section_name) == 0) {
return sections + i;
}
}
return NULL;
}
} // namespace google_breakpad
#endif // COMMON_LINUX_ELFUTILS_INL_H__

57
src/common/linux/elfutils.cc
View file

@ -33,6 +33,7 @@
#include <string.h> #include <string.h>
#include "common/linux/linux_libc_support.h" #include "common/linux/linux_libc_support.h"
#include "common/linux/elfutils-inl.h"
namespace google_breakpad { namespace google_breakpad {
@ -41,7 +42,7 @@ namespace {
template<typename ElfClass> template<typename ElfClass>
void FindElfClassSection(const char *elf_base, void FindElfClassSection(const char *elf_base,
const char *section_name, const char *section_name,
uint32_t section_type, typename ElfClass::Word section_type,
const void **section_start, const void **section_start,
int *section_size) { int *section_size) {
typedef typename ElfClass::Ehdr Ehdr; typedef typename ElfClass::Ehdr Ehdr;
@ -53,27 +54,21 @@ void FindElfClassSection(const char *elf_base,
assert(my_strncmp(elf_base, ELFMAG, SELFMAG) == 0); assert(my_strncmp(elf_base, ELFMAG, SELFMAG) == 0);
int name_len = my_strlen(section_name);
const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base); const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base);
assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass); assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass);
const Shdr* sections = const Shdr* sections =
reinterpret_cast<const Shdr*>(elf_base + elf_header->e_shoff); GetOffset<ElfClass,Shdr>(elf_header, elf_header->e_shoff);
const Shdr* string_section = sections + elf_header->e_shstrndx; 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;
const Shdr* section =
FindElfSectionByName<ElfClass>(section_name, section_type,
sections, names, names_end,
elf_header->e_shnum);
const Shdr* section = NULL;
for (int i = 0; i < elf_header->e_shnum; ++i) {
if (sections[i].sh_type == section_type) {
const char* current_section_name = (char*)(elf_base +
string_section->sh_offset +
sections[i].sh_name);
if (!my_strncmp(current_section_name, section_name, name_len)) {
section = &sections[i];
break;
}
}
}
if (section != NULL && section->sh_size > 0) { if (section != NULL && section->sh_size > 0) {
*section_start = elf_base + section->sh_offset; *section_start = elf_base + section->sh_offset;
*section_size = section->sh_size; *section_size = section->sh_size;
@ -82,6 +77,18 @@ void FindElfClassSection(const char *elf_base,
} // namespace } // namespace
bool IsValidElf(const void* elf_base) {
return my_strncmp(reinterpret_cast<const char*>(elf_base),
ELFMAG, SELFMAG) == 0;
}
int ElfClass(const void* elf_base) {
const ElfW(Ehdr)* elf_header =
reinterpret_cast<const ElfW(Ehdr)*>(elf_base);
return elf_header->e_ident[EI_CLASS];
}
bool FindElfSection(const void *elf_mapped_base, bool FindElfSection(const void *elf_mapped_base,
const char *section_name, const char *section_name,
uint32_t section_type, uint32_t section_type,
@ -95,22 +102,22 @@ bool FindElfSection(const void *elf_mapped_base,
*section_start = NULL; *section_start = NULL;
*section_size = 0; *section_size = 0;
const char* elf_base = if (!IsValidElf(elf_mapped_base))
static_cast<const char*>(elf_mapped_base);
const ElfW(Ehdr)* elf_header =
reinterpret_cast<const ElfW(Ehdr)*>(elf_base);
if (my_strncmp(elf_base, ELFMAG, SELFMAG) != 0)
return false; return false;
int cls = ElfClass(elf_mapped_base);
if (elfclass) { if (elfclass) {
*elfclass = elf_header->e_ident[EI_CLASS]; *elfclass = cls;
} }
if (elf_header->e_ident[EI_CLASS] == ELFCLASS32) { const char* elf_base =
static_cast<const char*>(elf_mapped_base);
if (cls == ELFCLASS32) {
FindElfClassSection<ElfClass32>(elf_base, section_name, section_type, FindElfClassSection<ElfClass32>(elf_base, section_name, section_type,
section_start, section_size); section_start, section_size);
return *section_start != NULL; return *section_start != NULL;
} else if (elf_header->e_ident[EI_CLASS] == ELFCLASS64) { } else if (cls == ELFCLASS64) {
FindElfClassSection<ElfClass64>(elf_base, section_name, section_type, FindElfClassSection<ElfClass64>(elf_base, section_name, section_type,
section_start, section_size); section_start, section_size);
return *section_start != NULL; return *section_start != NULL;

31
src/common/linux/elfutils.h
View file

@ -52,7 +52,11 @@ struct ElfClass32 {
typedef Elf32_Nhdr Nhdr; typedef Elf32_Nhdr Nhdr;
typedef Elf32_Phdr Phdr; typedef Elf32_Phdr Phdr;
typedef Elf32_Shdr Shdr; typedef Elf32_Shdr Shdr;
typedef Elf32_Half Half;
typedef Elf32_Off Off;
typedef Elf32_Word Word;
static const int kClass = ELFCLASS32; static const int kClass = ELFCLASS32;
static const size_t kAddrSize = sizeof(Elf32_Addr);
}; };
struct ElfClass64 { struct ElfClass64 {
@ -61,9 +65,16 @@ struct ElfClass64 {
typedef Elf64_Nhdr Nhdr; typedef Elf64_Nhdr Nhdr;
typedef Elf64_Phdr Phdr; typedef Elf64_Phdr Phdr;
typedef Elf64_Shdr Shdr; typedef Elf64_Shdr Shdr;
typedef Elf64_Half Half;
typedef Elf64_Off Off;
typedef Elf64_Word Word;
static const int kClass = ELFCLASS64; static const int kClass = ELFCLASS64;
static const size_t kAddrSize = sizeof(Elf64_Addr);
}; };
bool IsValidElf(const void* elf_header);
int ElfClass(const void* elf_base);
// Attempt to find a section named |section_name| of type |section_type| // Attempt to find a section named |section_name| of type |section_type|
// in the ELF binary data at |elf_mapped_base|. On success, returns true // in the ELF binary data at |elf_mapped_base|. On success, returns true
// and sets |*section_start| to point to the start of the section data, // and sets |*section_start| to point to the start of the section data,
@ -76,6 +87,26 @@ bool FindElfSection(const void *elf_mapped_base,
int *section_size, int *section_size,
int *elfclass); int *elfclass);
// Internal helper method, exposed for convenience for callers
// that already have more info.
template<typename ElfClass>
const typename ElfClass::Shdr*
FindElfSectionByName(const char* name,
typename ElfClass::Word section_type,
const typename ElfClass::Shdr* sections,
const char* section_names,
const char* names_end,
int nsection);
// Convert an offset from an Elf header into a pointer to the mapped
// address in the current process. Takes an extra template parameter
// to specify the return type to avoid having to dynamic_cast the
// result.
template<typename ElfClass, typename T>
const T*
GetOffset(const typename ElfClass::Ehdr* elf_header,
typename ElfClass::Off offset);
} // namespace google_breakpad } // namespace google_breakpad
#endif // COMMON_LINUX_ELFUTILS_H__ #endif // COMMON_LINUX_ELFUTILS_H__