| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * 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. |
| */ |
| |
| #ifndef LIBMEMUNREACHABLE_HEAP_WALKER_H_ |
| #define LIBMEMUNREACHABLE_HEAP_WALKER_H_ |
| |
| #include <signal.h> |
| |
| #include "android-base/macros.h" |
| |
| #include "Allocator.h" |
| #include "ScopedSignalHandler.h" |
| #include "Tarjan.h" |
| |
| namespace android { |
| |
| // A range [begin, end) |
| struct Range { |
| uintptr_t begin; |
| uintptr_t end; |
| |
| size_t size() const { return end - begin; }; |
| bool operator==(const Range& other) const { |
| return this->begin == other.begin && this->end == other.end; |
| } |
| bool operator!=(const Range& other) const { return !(*this == other); } |
| }; |
| |
| // Comparator for Ranges that returns equivalence for overlapping ranges |
| struct compare_range { |
| bool operator()(const Range& a, const Range& b) const { return a.end <= b.begin; } |
| }; |
| |
| class HeapWalker { |
| public: |
| explicit HeapWalker(Allocator<HeapWalker> allocator) |
| : allocator_(allocator), |
| allocations_(allocator), |
| allocation_bytes_(0), |
| roots_(allocator), |
| root_vals_(allocator), |
| segv_handler_(), |
| walking_ptr_(0), |
| walking_range_{0, 0}, |
| segv_logged_(false), |
| segv_page_count_(0) { |
| valid_allocations_range_.end = 0; |
| valid_allocations_range_.begin = ~valid_allocations_range_.end; |
| valid_mappings_range_.end = 0; |
| valid_mappings_range_.begin = ~valid_allocations_range_.end; |
| |
| segv_handler_.install( |
| SIGSEGV, [=](ScopedSignalHandler& handler, int signal, siginfo_t* siginfo, void* uctx) { |
| this->HandleSegFault(handler, signal, siginfo, uctx); |
| }); |
| } |
| |
| ~HeapWalker() {} |
| bool Allocation(uintptr_t begin, uintptr_t end); |
| void Mapping(uintptr_t begin, uintptr_t end); |
| void Root(uintptr_t begin, uintptr_t end); |
| void Root(const allocator::vector<uintptr_t>& vals); |
| |
| bool DetectLeaks(); |
| |
| bool Leaked(allocator::vector<Range>&, size_t limit, size_t* num_leaks, size_t* leak_bytes); |
| size_t Allocations(); |
| size_t AllocationBytes(); |
| |
| template <class F> |
| void ForEachPtrInRange(const Range& range, F&& f); |
| |
| template <class F> |
| void ForEachAllocation(F&& f); |
| |
| struct AllocationInfo { |
| bool referenced_from_root; |
| }; |
| |
| private: |
| void RecurseRoot(const Range& root); |
| bool WordContainsAllocationPtr(uintptr_t ptr, Range* range, AllocationInfo** info); |
| void HandleSegFault(ScopedSignalHandler&, int, siginfo_t*, void*); |
| |
| DISALLOW_COPY_AND_ASSIGN(HeapWalker); |
| Allocator<HeapWalker> allocator_; |
| using AllocationMap = allocator::map<Range, AllocationInfo, compare_range>; |
| AllocationMap allocations_; |
| size_t allocation_bytes_; |
| Range valid_allocations_range_; |
| Range valid_mappings_range_; |
| |
| allocator::vector<Range> roots_; |
| allocator::vector<uintptr_t> root_vals_; |
| |
| ScopedSignalHandler segv_handler_; |
| volatile uintptr_t walking_ptr_; |
| Range walking_range_; |
| bool segv_logged_; |
| size_t segv_page_count_; |
| }; |
| |
| template <class F> |
| inline void HeapWalker::ForEachPtrInRange(const Range& range, F&& f) { |
| uintptr_t begin = (range.begin + (sizeof(uintptr_t) - 1)) & ~(sizeof(uintptr_t) - 1); |
| // TODO(ccross): we might need to consider a pointer to the end of a buffer |
| // to be inside the buffer, which means the common case of a pointer to the |
| // beginning of a buffer may keep two ranges live. |
| for (uintptr_t i = begin; i < range.end; i += sizeof(uintptr_t)) { |
| Range ref_range; |
| AllocationInfo* ref_info; |
| if (WordContainsAllocationPtr(i, &ref_range, &ref_info)) { |
| f(ref_range, ref_info); |
| } |
| } |
| } |
| |
| template <class F> |
| inline void HeapWalker::ForEachAllocation(F&& f) { |
| for (auto& it : allocations_) { |
| const Range& range = it.first; |
| HeapWalker::AllocationInfo& allocation = it.second; |
| f(range, allocation); |
| } |
| } |
| |
| } // namespace android |
| |
| #endif |