diff options
Diffstat (limited to 'absl/base/internal/malloc_hook.cc')
| -rw-r--r-- | absl/base/internal/malloc_hook.cc | 611 |
1 files changed, 611 insertions, 0 deletions
diff --git a/absl/base/internal/malloc_hook.cc b/absl/base/internal/malloc_hook.cc new file mode 100644 index 00000000..d5d227a5 --- /dev/null +++ b/absl/base/internal/malloc_hook.cc @@ -0,0 +1,611 @@ +// Copyright 2017 The Abseil Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/base/config.h" + +#if ABSL_HAVE_MMAP +// Disable the glibc prototype of mremap(), as older versions of the +// system headers define this function with only four arguments, +// whereas newer versions allow an optional fifth argument: +#define mremap glibc_mremap +#include <sys/mman.h> +#undef mremap +#endif + +#include <cstddef> +#include <cstdint> +#include <algorithm> + +#include "absl/base/call_once.h" +#include "absl/base/casts.h" +#include "absl/base/internal/malloc_hook.h" +#include "absl/base/internal/malloc_hook_invoke.h" +#include "absl/base/internal/raw_logging.h" +#include "absl/base/internal/spinlock.h" + +// __THROW is defined in glibc systems. It means, counter-intuitively, +// "This function will never throw an exception." It's an optional +// optimization tool, but we may need to use it to match glibc prototypes. +#ifndef __THROW // I guess we're not on a glibc system +# define __THROW // __THROW is just an optimization, so ok to make it "" +#endif + +namespace absl { +namespace base_internal { +namespace { + +void RemoveInitialHooksAndCallInitializers(); // below. + +absl::once_flag once; + +// These hooks are installed in MallocHook as the only initial hooks. The first +// hook that is called will run RemoveInitialHooksAndCallInitializers (see the +// definition below) and then redispatch to any malloc hooks installed by +// RemoveInitialHooksAndCallInitializers. +// +// Note(llib): there is a possibility of a race in the event that there are +// multiple threads running before the first allocation. This is pretty +// difficult to achieve, but if it is then multiple threads may concurrently do +// allocations. The first caller will call +// RemoveInitialHooksAndCallInitializers via one of the initial hooks. A +// concurrent allocation may, depending on timing either: +// * still have its initial malloc hook installed, run that and block on waiting +// for the first caller to finish its call to +// RemoveInitialHooksAndCallInitializers, and proceed normally. +// * occur some time during the RemoveInitialHooksAndCallInitializers call, at +// which point there could be no initial hooks and the subsequent hooks that +// are about to be set up by RemoveInitialHooksAndCallInitializers haven't +// been installed yet. I think the worst we can get is that some allocations +// will not get reported to some hooks set by the initializers called from +// RemoveInitialHooksAndCallInitializers. + +void InitialNewHook(const void* ptr, size_t size) { + absl::call_once(once, RemoveInitialHooksAndCallInitializers); + MallocHook::InvokeNewHook(ptr, size); +} + +void InitialPreMMapHook(const void* start, + size_t size, + int protection, + int flags, + int fd, + off_t offset) { + absl::call_once(once, RemoveInitialHooksAndCallInitializers); + MallocHook::InvokePreMmapHook(start, size, protection, flags, fd, offset); +} + +void InitialPreSbrkHook(ptrdiff_t increment) { + absl::call_once(once, RemoveInitialHooksAndCallInitializers); + MallocHook::InvokePreSbrkHook(increment); +} + +// This function is called at most once by one of the above initial malloc +// hooks. It removes all initial hooks and initializes all other clients that +// want to get control at the very first memory allocation. The initializers +// may assume that the initial malloc hooks have been removed. The initializers +// may set up malloc hooks and allocate memory. +void RemoveInitialHooksAndCallInitializers() { + ABSL_RAW_CHECK(MallocHook::RemoveNewHook(&InitialNewHook), ""); + ABSL_RAW_CHECK(MallocHook::RemovePreMmapHook(&InitialPreMMapHook), ""); + ABSL_RAW_CHECK(MallocHook::RemovePreSbrkHook(&InitialPreSbrkHook), ""); +} + +} // namespace +} // namespace base_internal +} // namespace absl + +namespace absl { +namespace base_internal { + +// This lock is shared between all implementations of HookList::Add & Remove. +// The potential for contention is very small. This needs to be a SpinLock and +// not a Mutex since it's possible for Mutex locking to allocate memory (e.g., +// per-thread allocation in debug builds), which could cause infinite recursion. +static absl::base_internal::SpinLock hooklist_spinlock( + absl::base_internal::kLinkerInitialized); + +template <typename T> +bool HookList<T>::Add(T value_as_t) { + if (value_as_t == T()) { + return false; + } + absl::base_internal::SpinLockHolder l(&hooklist_spinlock); + // Find the first slot in data that is 0. + int index = 0; + while ((index < kHookListMaxValues) && + (priv_data[index].load(std::memory_order_relaxed) != 0)) { + ++index; + } + if (index == kHookListMaxValues) { + return false; + } + int prev_num_hooks = priv_end.load(std::memory_order_acquire); + priv_data[index].store(reinterpret_cast<intptr_t>(value_as_t), + std::memory_order_release); + if (prev_num_hooks <= index) { + priv_end.store(index + 1, std::memory_order_release); + } + return true; +} + +template <typename T> +bool HookList<T>::Remove(T value_as_t) { + if (value_as_t == T()) { + return false; + } + absl::base_internal::SpinLockHolder l(&hooklist_spinlock); + int hooks_end = priv_end.load(std::memory_order_acquire); + int index = 0; + while (index < hooks_end && + value_as_t != reinterpret_cast<T>( + priv_data[index].load(std::memory_order_acquire))) { + ++index; + } + if (index == hooks_end) { + return false; + } + priv_data[index].store(0, std::memory_order_release); + if (hooks_end == index + 1) { + // Adjust hooks_end down to the lowest possible value. + hooks_end = index; + while ((hooks_end > 0) && + (priv_data[hooks_end - 1].load(std::memory_order_acquire) == 0)) { + --hooks_end; + } + priv_end.store(hooks_end, std::memory_order_release); + } + return true; +} + +template <typename T> +int HookList<T>::Traverse(T* output_array, int n) const { + int hooks_end = priv_end.load(std::memory_order_acquire); + int actual_hooks_end = 0; + for (int i = 0; i < hooks_end && n > 0; ++i) { + T data = reinterpret_cast<T>(priv_data[i].load(std::memory_order_acquire)); + if (data != T()) { + *output_array++ = data; + ++actual_hooks_end; + --n; + } + } + return actual_hooks_end; +} + +// Initialize a HookList (optionally with the given initial_value in index 0). +#define INIT_HOOK_LIST { {0}, {{}} } +#define INIT_HOOK_LIST_WITH_VALUE(initial_value) \ + { {1}, { {reinterpret_cast<intptr_t>(initial_value)} } } + +// Explicit instantiation for malloc_hook_test.cc. This ensures all the methods +// are instantiated. +template struct HookList<MallocHook::NewHook>; + +HookList<MallocHook::NewHook> new_hooks_ = + INIT_HOOK_LIST_WITH_VALUE(&InitialNewHook); +HookList<MallocHook::DeleteHook> delete_hooks_ = INIT_HOOK_LIST; +HookList<MallocHook::SampledNewHook> sampled_new_hooks_ = INIT_HOOK_LIST; +HookList<MallocHook::SampledDeleteHook> sampled_delete_hooks_ = INIT_HOOK_LIST; +HookList<MallocHook::PreMmapHook> premmap_hooks_ = + INIT_HOOK_LIST_WITH_VALUE(&InitialPreMMapHook); +HookList<MallocHook::MmapHook> mmap_hooks_ = INIT_HOOK_LIST; +HookList<MallocHook::MunmapHook> munmap_hooks_ = INIT_HOOK_LIST; +HookList<MallocHook::MremapHook> mremap_hooks_ = INIT_HOOK_LIST; +HookList<MallocHook::PreSbrkHook> presbrk_hooks_ = + INIT_HOOK_LIST_WITH_VALUE(InitialPreSbrkHook); +HookList<MallocHook::SbrkHook> sbrk_hooks_ = INIT_HOOK_LIST; + +// These lists contain either 0 or 1 hooks. +HookList<MallocHook::MmapReplacement> mmap_replacement_ = INIT_HOOK_LIST; +HookList<MallocHook::MunmapReplacement> munmap_replacement_ = INIT_HOOK_LIST; + +#undef INIT_HOOK_LIST_WITH_VALUE +#undef INIT_HOOK_LIST + +} // namespace base_internal +} // namespace absl + +// These are available as C bindings as well as C++, hence their +// definition outside the MallocHook class. +extern "C" +int MallocHook_AddNewHook(MallocHook_NewHook hook) { + return absl::base_internal::new_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemoveNewHook(MallocHook_NewHook hook) { + return absl::base_internal::new_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_AddDeleteHook(MallocHook_DeleteHook hook) { + return absl::base_internal::delete_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemoveDeleteHook(MallocHook_DeleteHook hook) { + return absl::base_internal::delete_hooks_.Remove(hook); +} + +extern "C" int MallocHook_AddSampledNewHook(MallocHook_SampledNewHook hook) { + return absl::base_internal::sampled_new_hooks_.Add(hook); +} + +extern "C" int MallocHook_RemoveSampledNewHook(MallocHook_SampledNewHook hook) { + return absl::base_internal::sampled_new_hooks_.Remove(hook); +} + +extern "C" int MallocHook_AddSampledDeleteHook( + MallocHook_SampledDeleteHook hook) { + return absl::base_internal::sampled_delete_hooks_.Add(hook); +} + +extern "C" int MallocHook_RemoveSampledDeleteHook( + MallocHook_SampledDeleteHook hook) { + return absl::base_internal::sampled_delete_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_AddPreMmapHook(MallocHook_PreMmapHook hook) { + return absl::base_internal::premmap_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemovePreMmapHook(MallocHook_PreMmapHook hook) { + return absl::base_internal::premmap_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_SetMmapReplacement(MallocHook_MmapReplacement hook) { + // NOTE this is a best effort CHECK. Concurrent sets could succeed since + // this test is outside of the Add spin lock. + ABSL_RAW_CHECK(absl::base_internal::mmap_replacement_.empty(), + "Only one MMapReplacement is allowed."); + return absl::base_internal::mmap_replacement_.Add(hook); +} + +extern "C" +int MallocHook_RemoveMmapReplacement(MallocHook_MmapReplacement hook) { + return absl::base_internal::mmap_replacement_.Remove(hook); +} + +extern "C" +int MallocHook_AddMmapHook(MallocHook_MmapHook hook) { + return absl::base_internal::mmap_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemoveMmapHook(MallocHook_MmapHook hook) { + return absl::base_internal::mmap_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_AddMunmapHook(MallocHook_MunmapHook hook) { + return absl::base_internal::munmap_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemoveMunmapHook(MallocHook_MunmapHook hook) { + return absl::base_internal::munmap_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_SetMunmapReplacement(MallocHook_MunmapReplacement hook) { + // NOTE this is a best effort CHECK. Concurrent sets could succeed since + // this test is outside of the Add spin lock. + ABSL_RAW_CHECK(absl::base_internal::munmap_replacement_.empty(), + "Only one MunmapReplacement is allowed."); + return absl::base_internal::munmap_replacement_.Add(hook); +} + +extern "C" +int MallocHook_RemoveMunmapReplacement(MallocHook_MunmapReplacement hook) { + return absl::base_internal::munmap_replacement_.Remove(hook); +} + +extern "C" +int MallocHook_AddMremapHook(MallocHook_MremapHook hook) { + return absl::base_internal::mremap_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemoveMremapHook(MallocHook_MremapHook hook) { + return absl::base_internal::mremap_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_AddPreSbrkHook(MallocHook_PreSbrkHook hook) { + return absl::base_internal::presbrk_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemovePreSbrkHook(MallocHook_PreSbrkHook hook) { + return absl::base_internal::presbrk_hooks_.Remove(hook); +} + +extern "C" +int MallocHook_AddSbrkHook(MallocHook_SbrkHook hook) { + return absl::base_internal::sbrk_hooks_.Add(hook); +} + +extern "C" +int MallocHook_RemoveSbrkHook(MallocHook_SbrkHook hook) { + return absl::base_internal::sbrk_hooks_.Remove(hook); +} + +namespace absl { +namespace base_internal { + +// Note: embedding the function calls inside the traversal of HookList would be +// very confusing, as it is legal for a hook to remove itself and add other +// hooks. Doing traversal first, and then calling the hooks ensures we only +// call the hooks registered at the start. +#define INVOKE_HOOKS(HookType, hook_list, args) \ + do { \ + HookType hooks[kHookListMaxValues]; \ + int num_hooks = hook_list.Traverse(hooks, kHookListMaxValues); \ + for (int i = 0; i < num_hooks; ++i) { \ + (*hooks[i]) args; \ + } \ + } while (0) + +// There should only be one replacement. Return the result of the first +// one, or false if there is none. +#define INVOKE_REPLACEMENT(HookType, hook_list, args) \ + do { \ + HookType hooks[kHookListMaxValues]; \ + int num_hooks = hook_list.Traverse(hooks, kHookListMaxValues); \ + return (num_hooks > 0 && (*hooks[0])args); \ + } while (0) + +void MallocHook::InvokeNewHookSlow(const void* ptr, size_t size) { + INVOKE_HOOKS(NewHook, new_hooks_, (ptr, size)); +} + +void MallocHook::InvokeDeleteHookSlow(const void* ptr) { + INVOKE_HOOKS(DeleteHook, delete_hooks_, (ptr)); +} + +void MallocHook::InvokeSampledNewHookSlow(const SampledAlloc* sampled_alloc) { + INVOKE_HOOKS(SampledNewHook, sampled_new_hooks_, (sampled_alloc)); +} + +void MallocHook::InvokeSampledDeleteHookSlow(AllocHandle handle) { + INVOKE_HOOKS(SampledDeleteHook, sampled_delete_hooks_, (handle)); +} + +void MallocHook::InvokePreMmapHookSlow(const void* start, + size_t size, + int protection, + int flags, + int fd, + off_t offset) { + INVOKE_HOOKS(PreMmapHook, premmap_hooks_, (start, size, protection, flags, fd, + offset)); +} + +void MallocHook::InvokeMmapHookSlow(const void* result, + const void* start, + size_t size, + int protection, + int flags, + int fd, + off_t offset) { + INVOKE_HOOKS(MmapHook, mmap_hooks_, (result, start, size, protection, flags, + fd, offset)); +} + +bool MallocHook::InvokeMmapReplacementSlow(const void* start, + size_t size, + int protection, + int flags, + int fd, + off_t offset, + void** result) { + INVOKE_REPLACEMENT(MmapReplacement, mmap_replacement_, + (start, size, protection, flags, fd, offset, result)); +} + +void MallocHook::InvokeMunmapHookSlow(const void* start, size_t size) { + INVOKE_HOOKS(MunmapHook, munmap_hooks_, (start, size)); +} + +bool MallocHook::InvokeMunmapReplacementSlow(const void* start, + size_t size, + int* result) { + INVOKE_REPLACEMENT(MunmapReplacement, munmap_replacement_, + (start, size, result)); +} + +void MallocHook::InvokeMremapHookSlow(const void* result, + const void* old_addr, + size_t old_size, + size_t new_size, + int flags, + const void* new_addr) { + INVOKE_HOOKS(MremapHook, mremap_hooks_, (result, old_addr, old_size, new_size, + flags, new_addr)); +} + +void MallocHook::InvokePreSbrkHookSlow(ptrdiff_t increment) { + INVOKE_HOOKS(PreSbrkHook, presbrk_hooks_, (increment)); +} + +void MallocHook::InvokeSbrkHookSlow(const void* result, ptrdiff_t increment) { + INVOKE_HOOKS(SbrkHook, sbrk_hooks_, (result, increment)); +} + +#undef INVOKE_HOOKS +#undef INVOKE_REPLACEMENT + +} // namespace base_internal +} // namespace absl + +ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(google_malloc); +ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(google_malloc); +// actual functions are in debugallocation.cc or tcmalloc.cc +ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(malloc_hook); +ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(malloc_hook); +// actual functions are in this file, malloc_hook.cc, and low_level_alloc.cc +ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(blink_malloc); +ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(blink_malloc); +// actual functions are in third_party/blink_headless/.../{PartitionAlloc, +// FastMalloc}.cpp. + +#define ADDR_IN_ATTRIBUTE_SECTION(addr, name) \ + (reinterpret_cast<uintptr_t>(ABSL_ATTRIBUTE_SECTION_START(name)) <= \ + reinterpret_cast<uintptr_t>(addr) && \ + reinterpret_cast<uintptr_t>(addr) < \ + reinterpret_cast<uintptr_t>(ABSL_ATTRIBUTE_SECTION_STOP(name))) + +// Return true iff 'caller' is a return address within a function +// that calls one of our hooks via MallocHook:Invoke*. +// A helper for GetCallerStackTrace. +static inline bool InHookCaller(const void* caller) { + return ADDR_IN_ATTRIBUTE_SECTION(caller, google_malloc) || + ADDR_IN_ATTRIBUTE_SECTION(caller, malloc_hook) || + ADDR_IN_ATTRIBUTE_SECTION(caller, blink_malloc); + // We can use one section for everything except tcmalloc_or_debug + // due to its special linkage mode, which prevents merging of the sections. +} + +#undef ADDR_IN_ATTRIBUTE_SECTION + +static absl::once_flag in_hook_caller_once; + +static void InitializeInHookCaller() { + ABSL_INIT_ATTRIBUTE_SECTION_VARS(google_malloc); + if (ABSL_ATTRIBUTE_SECTION_START(google_malloc) == + ABSL_ATTRIBUTE_SECTION_STOP(google_malloc)) { + ABSL_RAW_LOG(ERROR, + "google_malloc section is missing, " + "thus InHookCaller is broken!"); + } + ABSL_INIT_ATTRIBUTE_SECTION_VARS(malloc_hook); + if (ABSL_ATTRIBUTE_SECTION_START(malloc_hook) == + ABSL_ATTRIBUTE_SECTION_STOP(malloc_hook)) { + ABSL_RAW_LOG(ERROR, + "malloc_hook section is missing, " + "thus InHookCaller is broken!"); + } + ABSL_INIT_ATTRIBUTE_SECTION_VARS(blink_malloc); + // The blink_malloc section is only expected to be present in binaries + // linking against the blink rendering engine in third_party/blink_headless. +} + +// We can improve behavior/compactness of this function +// if we pass a generic test function (with a generic arg) +// into the implementations for get_stack_trace_fn instead of the skip_count. +extern "C" int MallocHook_GetCallerStackTrace( + void** result, int max_depth, int skip_count, + MallocHook_GetStackTraceFn get_stack_trace_fn) { + if (!ABSL_HAVE_ATTRIBUTE_SECTION) { + // Fall back to get_stack_trace_fn and good old but fragile frame skip + // counts. + // Note: this path is inaccurate when a hook is not called directly by an + // allocation function but is daisy-chained through another hook, + // search for MallocHook::(Get|Set|Invoke)* to find such cases. +#ifdef NDEBUG + return get_stack_trace_fn(result, max_depth, skip_count); +#else + return get_stack_trace_fn(result, max_depth, skip_count + 1); +#endif + // due to -foptimize-sibling-calls in opt mode + // there's no need for extra frame skip here then + } + absl::call_once(in_hook_caller_once, InitializeInHookCaller); + // MallocHook caller determination via InHookCaller works, use it: + static const int kMaxSkip = 32 + 6 + 3; + // Constant tuned to do just one get_stack_trace_fn call below in practice + // and not get many frames that we don't actually need: + // currently max passed max_depth is 32, + // max passed/needed skip_count is 6 + // and 3 is to account for some hook daisy chaining. + static const int kStackSize = kMaxSkip + 1; + void* stack[kStackSize]; + int depth = + get_stack_trace_fn(stack, kStackSize, 1); // skip this function frame + if (depth == 0) + // silently propagate cases when get_stack_trace_fn does not work + return 0; + for (int i = depth - 1; i >= 0; --i) { // stack[0] is our immediate caller + if (InHookCaller(stack[i])) { + i += 1; // skip hook caller frame + depth -= i; // correct depth + if (depth > max_depth) depth = max_depth; + std::copy(stack + i, stack + i + depth, result); + if (depth < max_depth && depth + i == kStackSize) { + // get frames for the missing depth + depth += get_stack_trace_fn(result + depth, max_depth - depth, + 1 + kStackSize); + } + return depth; + } + } + ABSL_RAW_LOG(WARNING, + "Hooked allocator frame not found, returning empty trace"); + // If this happens try increasing kMaxSkip + // or else something must be wrong with InHookCaller, + // e.g. for every section used in InHookCaller + // all functions in that section must be inside the same library. + return 0; +} + +// On systems where we know how, we override mmap/munmap/mremap/sbrk +// to provide support for calling the related hooks (in addition, +// of course, to doing what these functions normally do). + +// The ABSL_MALLOC_HOOK_MMAP_DISABLE macro disables mmap/munmap interceptors. +// Dynamic tools that intercept mmap/munmap can't be linked together with +// malloc_hook interceptors. We disable the malloc_hook interceptors for the +// widely-used dynamic tools, i.e. ThreadSanitizer and MemorySanitizer, but +// still allow users to disable this in special cases that can't be easily +// detected during compilation, via -DABSL_MALLOC_HOOK_MMAP_DISABLE or #define +// ABSL_MALLOC_HOOK_MMAP_DISABLE. +// TODO(b/62370839): Remove MALLOC_HOOK_MMAP_DISABLE in CROSSTOOL for tsan and +// msan config; Replace MALLOC_HOOK_MMAP_DISABLE with +// ABSL_MALLOC_HOOK_MMAP_DISABLE for other special cases. +#if !defined(THREAD_SANITIZER) && !defined(MEMORY_SANITIZER) && \ + !defined(ABSL_MALLOC_HOOK_MMAP_DISABLE) && defined(__linux__) +#include "absl/base/internal/malloc_hook_mmap_linux.inc" + +#elif ABSL_HAVE_MMAP + +namespace absl { +namespace base_internal { + +// static +void* MallocHook::UnhookedMMap(void* start, size_t size, int protection, + int flags, int fd, off_t offset) { + void* result; + if (!MallocHook::InvokeMmapReplacement( + start, size, protection, flags, fd, offset, &result)) { + result = mmap(start, size, protection, flags, fd, offset); + } + return result; +} + +// static +int MallocHook::UnhookedMUnmap(void* start, size_t size) { + int result; + if (!MallocHook::InvokeMunmapReplacement(start, size, &result)) { + result = munmap(start, size); + } + return result; +} + +} // namespace base_internal +} // namespace absl + +#endif |