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Diffstat (limited to 'toolkit/crashreporter/google-breakpad/src/common/memory.h')
-rw-r--r-- | toolkit/crashreporter/google-breakpad/src/common/memory.h | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/toolkit/crashreporter/google-breakpad/src/common/memory.h b/toolkit/crashreporter/google-breakpad/src/common/memory.h new file mode 100644 index 000000000..9158b50c8 --- /dev/null +++ b/toolkit/crashreporter/google-breakpad/src/common/memory.h @@ -0,0 +1,249 @@ +// Copyright (c) 2009, 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 GOOGLE_BREAKPAD_COMMON_MEMORY_H_ +#define GOOGLE_BREAKPAD_COMMON_MEMORY_H_ + +#include <stdint.h> +#include <stdlib.h> +#include <unistd.h> +#include <sys/mman.h> + +#include <memory> +#include <vector> + +#if defined(MEMORY_SANITIZER) +#include <sanitizer/msan_interface.h> +#endif + +#ifdef __APPLE__ +#define sys_mmap mmap +#define sys_munmap munmap +#define MAP_ANONYMOUS MAP_ANON +#else +#include "third_party/lss/linux_syscall_support.h" +#endif + +namespace google_breakpad { + +// This is very simple allocator which fetches pages from the kernel directly. +// Thus, it can be used even when the heap may be corrupted. +// +// There is no free operation. The pages are only freed when the object is +// destroyed. +class PageAllocator { + public: + PageAllocator() + : page_size_(getpagesize()), + last_(NULL), + current_page_(NULL), + page_offset_(0), + pages_allocated_(0) { + } + + ~PageAllocator() { + FreeAll(); + } + + void *Alloc(size_t bytes) { + if (!bytes) + return NULL; + + if (current_page_ && page_size_ - page_offset_ >= bytes) { + uint8_t *const ret = current_page_ + page_offset_; + page_offset_ += bytes; + if (page_offset_ == page_size_) { + page_offset_ = 0; + current_page_ = NULL; + } + + return ret; + } + + const size_t pages = + (bytes + sizeof(PageHeader) + page_size_ - 1) / page_size_; + uint8_t *const ret = GetNPages(pages); + if (!ret) + return NULL; + + page_offset_ = + (page_size_ - (page_size_ * pages - (bytes + sizeof(PageHeader)))) % + page_size_; + current_page_ = page_offset_ ? ret + page_size_ * (pages - 1) : NULL; + + return ret + sizeof(PageHeader); + } + + // Checks whether the page allocator owns the passed-in pointer. + // This method exists for testing pursposes only. + bool OwnsPointer(const void* p) { + for (PageHeader* header = last_; header; header = header->next) { + const char* current = reinterpret_cast<char*>(header); + if ((p >= current) && (p < current + header->num_pages * page_size_)) + return true; + } + + return false; + } + + unsigned long pages_allocated() { return pages_allocated_; } + + private: + uint8_t *GetNPages(size_t num_pages) { + void *a = sys_mmap(NULL, page_size_ * num_pages, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (a == MAP_FAILED) + return NULL; + +#if defined(MEMORY_SANITIZER) + // We need to indicate to MSan that memory allocated through sys_mmap is + // initialized, since linux_syscall_support.h doesn't have MSan hooks. + __msan_unpoison(a, page_size_ * num_pages); +#endif + + struct PageHeader *header = reinterpret_cast<PageHeader*>(a); + header->next = last_; + header->num_pages = num_pages; + last_ = header; + + pages_allocated_ += num_pages; + + return reinterpret_cast<uint8_t*>(a); + } + + void FreeAll() { + PageHeader *next; + + for (PageHeader *cur = last_; cur; cur = next) { + next = cur->next; + sys_munmap(cur, cur->num_pages * page_size_); + } + } + + struct PageHeader { + PageHeader *next; // pointer to the start of the next set of pages. + size_t num_pages; // the number of pages in this set. + }; + + const size_t page_size_; + PageHeader *last_; + uint8_t *current_page_; + size_t page_offset_; + unsigned long pages_allocated_; +}; + +// Wrapper to use with STL containers +template <typename T> +struct PageStdAllocator : public std::allocator<T> { + typedef typename std::allocator<T>::pointer pointer; + typedef typename std::allocator<T>::size_type size_type; + + explicit PageStdAllocator(PageAllocator& allocator) : allocator_(allocator), + stackdata_(NULL), + stackdata_size_(0) + {} + + template <class Other> PageStdAllocator(const PageStdAllocator<Other>& other) + : allocator_(other.allocator_), + stackdata_(nullptr), + stackdata_size_(0) + {} + + explicit PageStdAllocator(PageAllocator& allocator, + pointer stackdata, + size_type stackdata_size) : allocator_(allocator), + stackdata_(stackdata), + stackdata_size_(stackdata_size) + {} + + inline pointer allocate(size_type n, const void* = 0) { + const size_type size = sizeof(T) * n; + if (size <= stackdata_size_) { + return stackdata_; + } + return static_cast<pointer>(allocator_.Alloc(size)); + } + + inline void deallocate(pointer, size_type) { + // The PageAllocator doesn't free. + } + + template <typename U> struct rebind { + typedef PageStdAllocator<U> other; + }; + + private: + // Silly workaround for the gcc from Android's ndk (gcc 4.6), which will + // otherwise complain that `other.allocator_` is private in the constructor + // code. + template<typename Other> friend struct PageStdAllocator; + + PageAllocator& allocator_; + pointer stackdata_; + size_type stackdata_size_; +}; + +// A wasteful vector is a std::vector, except that it allocates memory from a +// PageAllocator. It's wasteful because, when resizing, it always allocates a +// whole new array since the PageAllocator doesn't support realloc. +template<class T> +class wasteful_vector : public std::vector<T, PageStdAllocator<T> > { + public: + wasteful_vector(PageAllocator* allocator, unsigned size_hint = 16) + : std::vector<T, PageStdAllocator<T> >(PageStdAllocator<T>(*allocator)) { + std::vector<T, PageStdAllocator<T> >::reserve(size_hint); + } + protected: + wasteful_vector(PageStdAllocator<T> allocator) + : std::vector<T, PageStdAllocator<T> >(allocator) {} +}; + +// auto_wasteful_vector allocates space on the stack for N entries to avoid +// using the PageAllocator for small data, while still allowing for larger data. +template<class T, unsigned int N> +class auto_wasteful_vector : public wasteful_vector<T> { + T stackdata_[N]; + public: + auto_wasteful_vector(PageAllocator* allocator) + : wasteful_vector<T>( + PageStdAllocator<T>(*allocator, + &stackdata_[0], + sizeof(stackdata_))) { + std::vector<T, PageStdAllocator<T> >::reserve(N); + } +}; + +} // namespace google_breakpad + +inline void* operator new(size_t nbytes, + google_breakpad::PageAllocator& allocator) { + return allocator.Alloc(nbytes); +} + +#endif // GOOGLE_BREAKPAD_COMMON_MEMORY_H_ |