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issue 243 - Linux dumper should use build id produced by ld --build-id if available

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R=thestig at http://breakpad.appspot.com/185001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@830 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
ted.mielczarek
2011-08-30 15:21:07 +00:00
parent 68e380d5a7
commit 8ade75f955
5 changed files with 259 additions and 95 deletions
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160
src/common/linux/file_id.cc
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@@ -56,39 +56,46 @@
namespace google_breakpad {
#ifndef NT_GNU_BUILD_ID
#define NT_GNU_BUILD_ID 3
#endif
FileID::FileID(const char* path) {
strncpy(path_, path, sizeof(path_));
}
struct ElfClass32 {
typedef Elf32_Ehdr Ehdr;
typedef Elf32_Nhdr Nhdr;
typedef Elf32_Shdr Shdr;
static const int kClass = ELFCLASS32;
};
struct ElfClass64 {
typedef Elf64_Ehdr Ehdr;
typedef Elf64_Nhdr Nhdr;
typedef Elf64_Shdr Shdr;
static const int kClass = ELFCLASS64;
};
// These three functions are also used inside the crashed process, so be safe
// These six functions are also used inside the crashed process, so be safe
// and use the syscall/libc wrappers instead of direct syscalls or libc.
template<typename ElfClass>
static void FindElfClassTextSection(const char *elf_base,
const void **text_start,
int *text_size) {
static void FindElfClassSection(const char *elf_base,
const char *section_name,
uint32_t section_type,
const void **section_start,
int *section_size) {
typedef typename ElfClass::Ehdr Ehdr;
typedef typename ElfClass::Shdr Shdr;
assert(elf_base);
assert(text_start);
assert(text_size);
assert(section_start);
assert(section_size);
assert(my_strncmp(elf_base, ELFMAG, SELFMAG) == 0);
const char* text_section_name = ".text";
int name_len = my_strlen(text_section_name);
int name_len = my_strlen(section_name);
const Ehdr* elf_header = reinterpret_cast<const Ehdr*>(elf_base);
assert(elf_header->e_ident[EI_CLASS] == ElfClass::kClass);
@@ -97,30 +104,41 @@ static void FindElfClassTextSection(const char *elf_base,
reinterpret_cast<const Shdr*>(elf_base + elf_header->e_shoff);
const Shdr* string_section = sections + elf_header->e_shstrndx;
const Shdr* text_section = NULL;
const Shdr* section = NULL;
for (int i = 0; i < elf_header->e_shnum; ++i) {
if (sections[i].sh_type == SHT_PROGBITS) {
if (sections[i].sh_type == section_type) {
const char* section_name = (char*)(elf_base +
string_section->sh_offset +
sections[i].sh_name);
if (!my_strncmp(section_name, text_section_name, name_len)) {
text_section = &sections[i];
if (!my_strncmp(section_name, section_name, name_len)) {
section = &sections[i];
break;
}
}
}
if (text_section != NULL && text_section->sh_size > 0) {
*text_start = elf_base + text_section->sh_offset;
*text_size = text_section->sh_size;
if (section != NULL && section->sh_size > 0) {
*section_start = elf_base + section->sh_offset;
*section_size = section->sh_size;
}
}
static bool FindElfTextSection(const void *elf_mapped_base,
const void **text_start,
int *text_size) {
// 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
// and sets |*section_start| to point to the start of the section data,
// and |*section_size| to the size of the section's data. If |elfclass|
// is not NULL, set |*elfclass| to the ELF file class.
static bool FindElfSection(const void *elf_mapped_base,
const char *section_name,
uint32_t section_type,
const void **section_start,
int *section_size,
int *elfclass) {
assert(elf_mapped_base);
assert(text_start);
assert(text_size);
assert(section_start);
assert(section_size);
*section_start = NULL;
*section_size = 0;
const char* elf_base =
static_cast<const char*>(elf_mapped_base);
@@ -129,14 +147,89 @@ static bool FindElfTextSection(const void *elf_mapped_base,
if (my_strncmp(elf_base, ELFMAG, SELFMAG) != 0)
return false;
if (elfclass) {
*elfclass = elf_header->e_ident[EI_CLASS];
}
if (elf_header->e_ident[EI_CLASS] == ELFCLASS32) {
FindElfClassTextSection<ElfClass32>(elf_base, text_start, text_size);
FindElfClassSection<ElfClass32>(elf_base, section_name, section_type,
section_start, section_size);
return *section_start != NULL;
} else if (elf_header->e_ident[EI_CLASS] == ELFCLASS64) {
FindElfClassTextSection<ElfClass64>(elf_base, text_start, text_size);
} else {
FindElfClassSection<ElfClass64>(elf_base, section_name, section_type,
section_start, section_size);
return *section_start != NULL;
}
return false;
}
template<typename ElfClass>
static bool ElfClassBuildIDNoteIdentifier(const void *section,
uint8_t identifier[kMDGUIDSize])
{
typedef typename ElfClass::Nhdr Nhdr;
const Nhdr* note_header = reinterpret_cast<const Nhdr*>(section);
if (note_header->n_type != NT_GNU_BUILD_ID ||
note_header->n_descsz == 0) {
return false;
}
const char* build_id = reinterpret_cast<const char*>(section) +
sizeof(Nhdr) + note_header->n_namesz;
// Copy as many bits of the build ID as will fit
// into the GUID space.
my_memset(identifier, 0, kMDGUIDSize);
memcpy(identifier, build_id,
std::min(kMDGUIDSize, (size_t)note_header->n_descsz));
return true;
}
// Attempt to locate a .note.gnu.build-id section in an ELF binary
// and copy as many bytes of it as will fit into |identifier|.
static bool FindElfBuildIDNote(const void *elf_mapped_base,
uint8_t identifier[kMDGUIDSize])
{
void* note_section;
int note_size, elfclass;
if (!FindElfSection(elf_mapped_base, ".note.gnu.build-id", SHT_NOTE,
(const void**)&note_section, &note_size, &elfclass) ||
note_size == 0) {
return false;
}
if (elfclass == ELFCLASS32) {
return ElfClassBuildIDNoteIdentifier<ElfClass32>(note_section, identifier);
} else if (elfclass == ELFCLASS64) {
return ElfClassBuildIDNoteIdentifier<ElfClass64>(note_section, identifier);
}
return false;
}
// Attempt to locate the .text section of an ELF binary and generate
// a simple hash by XORing the first page worth of bytes into |identifier|.
static bool HashElfTextSection(const void *elf_mapped_base,
uint8_t identifier[kMDGUIDSize]) {
void* text_section;
int text_size;
if (!FindElfSection(elf_mapped_base, ".text", SHT_PROGBITS,
(const void**)&text_section, &text_size, NULL) ||
text_size == 0) {
return false;
}
my_memset(identifier, 0, kMDGUIDSize);
const uint8_t* ptr = reinterpret_cast<const uint8_t*>(text_section);
const uint8_t* ptr_end = ptr + std::min(text_size, 4096);
while (ptr < ptr_end) {
for (unsigned i = 0; i < kMDGUIDSize; i++)
identifier[i] ^= ptr[i];
ptr += kMDGUIDSize;
}
return true;
}
@@ -144,21 +237,12 @@ static bool FindElfTextSection(const void *elf_mapped_base,
bool FileID::ElfFileIdentifierFromMappedFile(void* base,
uint8_t identifier[kMDGUIDSize])
{
const void* text_section = NULL;
int text_size = 0;
bool success = false;
if (FindElfTextSection(base, &text_section, &text_size) && (text_size > 0)) {
my_memset(identifier, 0, kMDGUIDSize);
const uint8_t* ptr = reinterpret_cast<const uint8_t*>(text_section);
const uint8_t* ptr_end = ptr + std::min(text_size, 4096);
while (ptr < ptr_end) {
for (unsigned i = 0; i < kMDGUIDSize; i++)
identifier[i] ^= ptr[i];
ptr += kMDGUIDSize;
}
success = true;
}
return success;
// Look for a build id note first.
if (FindElfBuildIDNote(base, identifier))
return true;
// Fall back on hashing the first page of the text section.
return HashElfTextSection(base, identifier);
}
bool FileID::ElfFileIdentifier(uint8_t identifier[kMDGUIDSize]) {