blob: fa94306e8736e28dce8c5da8aa32e672db8ccb32 [file] [log] [blame]
// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/profiler/module_cache.h"
#include <dlfcn.h>
#include <mach-o/getsect.h>
#include <uuid/uuid.h>
#include "base/strings/string_number_conversions.h"
namespace base {
namespace {
// Returns the unique build ID for a module loaded at |module_addr|. Returns the
// empty string if the function fails to get the build ID.
// Build IDs are created by the concatenation of the module's GUID (Windows) /
// UUID (Mac) and an "age" field that indicates how many times that GUID/UUID
// has been reused. In Windows binaries, the "age" field is present in the
// module header, but on the Mac, UUIDs are never reused and so the "age" value
// appended to the UUID is always 0.
std::string GetUniqueId(const void* module_addr) {
const mach_header_64* mach_header =
reinterpret_cast<const mach_header_64*>(module_addr);
DCHECK_EQ(MH_MAGIC_64, mach_header->magic);
size_t offset = sizeof(mach_header_64);
size_t offset_limit = sizeof(mach_header_64) + mach_header->sizeofcmds;
for (uint32_t i = 0; i < mach_header->ncmds; ++i) {
if (offset + sizeof(load_command) >= offset_limit)
return std::string();
const load_command* current_cmd = reinterpret_cast<const load_command*>(
reinterpret_cast<const uint8_t*>(mach_header) + offset);
if (offset + current_cmd->cmdsize > offset_limit) {
// This command runs off the end of the command list. This is malformed.
return std::string();
if (current_cmd->cmd == LC_UUID) {
if (current_cmd->cmdsize < sizeof(uuid_command)) {
// This "UUID command" is too small. This is malformed.
return std::string();
const uuid_command* uuid_cmd =
reinterpret_cast<const uuid_command*>(current_cmd);
static_assert(sizeof(uuid_cmd->uuid) == sizeof(uuid_t),
"UUID field of UUID command should be 16 bytes.");
// The ID is comprised of the UUID concatenated with the Mac's "age" value
// which is always 0.
return HexEncode(&uuid_cmd->uuid, sizeof(uuid_cmd->uuid)) + "0";
offset += current_cmd->cmdsize;
return std::string();
// Returns the size of the _TEXT segment of the module loaded at |module_addr|.
size_t GetModuleTextSize(const void* module_addr) {
const mach_header_64* mach_header =
reinterpret_cast<const mach_header_64*>(module_addr);
DCHECK_EQ(MH_MAGIC_64, mach_header->magic);
unsigned long module_size;
getsegmentdata(mach_header, SEG_TEXT, &module_size);
return module_size;
} // namespace
class MacModule : public ModuleCache::Module {
MacModule(const Dl_info& dl_info)
: base_address_(reinterpret_cast<uintptr_t>(dl_info.dli_fbase)),
size_(GetModuleTextSize(dl_info.dli_fbase)) {}
MacModule(const MacModule&) = delete;
MacModule& operator=(const MacModule&) = delete;
// ModuleCache::Module
uintptr_t GetBaseAddress() const override { return base_address_; }
std::string GetId() const override { return id_; }
FilePath GetDebugBasename() const override { return debug_basename_; }
size_t GetSize() const override { return size_; }
bool IsNative() const override { return true; }
uintptr_t base_address_;
std::string id_;
FilePath debug_basename_;
size_t size_;
// static
std::unique_ptr<ModuleCache::Module> ModuleCache::CreateModuleForAddress(
uintptr_t address) {
Dl_info info;
if (!dladdr(reinterpret_cast<const void*>(address), &info))
return nullptr;
return std::make_unique<MacModule>(info);
} // namespace base