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- // -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
- // Copyright (c) 2014, gperftools Contributors
- // 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.
- //
- #include "config.h"
- #include "emergency_malloc.h"
- #include <errno.h> // for ENOMEM, errno
- #include <string.h> // for memset
- #include "base/basictypes.h"
- #include "base/logging.h"
- #include "base/low_level_alloc.h"
- #include "base/spinlock.h"
- #include "internal_logging.h"
- namespace tcmalloc {
- __attribute__ ((visibility("internal"))) char *emergency_arena_start;
- __attribute__ ((visibility("internal"))) uintptr_t emergency_arena_start_shifted;
- static CACHELINE_ALIGNED SpinLock emergency_malloc_lock(base::LINKER_INITIALIZED);
- static char *emergency_arena_end;
- static LowLevelAlloc::Arena *emergency_arena;
- class EmergencyArenaPagesAllocator : public LowLevelAlloc::PagesAllocator {
- ~EmergencyArenaPagesAllocator() {}
- void *MapPages(int32 flags, size_t size) {
- char *new_end = emergency_arena_end + size;
- if (new_end > emergency_arena_start + kEmergencyArenaSize) {
- RAW_LOG(FATAL, "Unable to allocate %" PRIuS " bytes in emergency zone.", size);
- }
- char *rv = emergency_arena_end;
- emergency_arena_end = new_end;
- return static_cast<void *>(rv);
- }
- void UnMapPages(int32 flags, void *addr, size_t size) {
- RAW_LOG(FATAL, "UnMapPages is not implemented for emergency arena");
- }
- };
- static union {
- char bytes[sizeof(EmergencyArenaPagesAllocator)];
- void *ptr;
- } pages_allocator_place;
- static void InitEmergencyMalloc(void) {
- const int32 flags = LowLevelAlloc::kAsyncSignalSafe;
- void *arena = LowLevelAlloc::GetDefaultPagesAllocator()->MapPages(flags, kEmergencyArenaSize * 2);
- uintptr_t arena_ptr = reinterpret_cast<uintptr_t>(arena);
- uintptr_t ptr = (arena_ptr + kEmergencyArenaSize - 1) & ~(kEmergencyArenaSize-1);
- emergency_arena_end = emergency_arena_start = reinterpret_cast<char *>(ptr);
- EmergencyArenaPagesAllocator *allocator = new (pages_allocator_place.bytes) EmergencyArenaPagesAllocator();
- emergency_arena = LowLevelAlloc::NewArenaWithCustomAlloc(0, LowLevelAlloc::DefaultArena(), allocator);
- emergency_arena_start_shifted = reinterpret_cast<uintptr_t>(emergency_arena_start) >> kEmergencyArenaShift;
- uintptr_t head_unmap_size = ptr - arena_ptr;
- CHECK_CONDITION(head_unmap_size < kEmergencyArenaSize);
- if (head_unmap_size != 0) {
- LowLevelAlloc::GetDefaultPagesAllocator()->UnMapPages(flags, arena, ptr - arena_ptr);
- }
- uintptr_t tail_unmap_size = kEmergencyArenaSize - head_unmap_size;
- void *tail_start = reinterpret_cast<void *>(arena_ptr + head_unmap_size + kEmergencyArenaSize);
- LowLevelAlloc::GetDefaultPagesAllocator()->UnMapPages(flags, tail_start, tail_unmap_size);
- }
- PERFTOOLS_DLL_DECL void *EmergencyMalloc(size_t size) {
- SpinLockHolder l(&emergency_malloc_lock);
- if (emergency_arena_start == NULL) {
- InitEmergencyMalloc();
- CHECK_CONDITION(emergency_arena_start != NULL);
- }
- void *rv = LowLevelAlloc::AllocWithArena(size, emergency_arena);
- if (rv == NULL) {
- errno = ENOMEM;
- }
- return rv;
- }
- PERFTOOLS_DLL_DECL void EmergencyFree(void *p) {
- SpinLockHolder l(&emergency_malloc_lock);
- if (emergency_arena_start == NULL) {
- InitEmergencyMalloc();
- CHECK_CONDITION(emergency_arena_start != NULL);
- free(p);
- return;
- }
- CHECK_CONDITION(emergency_arena_start);
- LowLevelAlloc::Free(p);
- }
- PERFTOOLS_DLL_DECL void *EmergencyRealloc(void *_old_ptr, size_t new_size) {
- if (_old_ptr == NULL) {
- return EmergencyMalloc(new_size);
- }
- if (new_size == 0) {
- EmergencyFree(_old_ptr);
- return NULL;
- }
- SpinLockHolder l(&emergency_malloc_lock);
- CHECK_CONDITION(emergency_arena_start);
- char *old_ptr = static_cast<char *>(_old_ptr);
- CHECK_CONDITION(old_ptr <= emergency_arena_end);
- CHECK_CONDITION(emergency_arena_start <= old_ptr);
- // NOTE: we don't know previous size of old_ptr chunk. So instead
- // of trying to figure out right size of copied memory, we just
- // copy largest possible size. We don't care about being slow.
- size_t old_ptr_size = emergency_arena_end - old_ptr;
- size_t copy_size = (new_size < old_ptr_size) ? new_size : old_ptr_size;
- void *new_ptr = LowLevelAlloc::AllocWithArena(new_size, emergency_arena);
- if (new_ptr == NULL) {
- errno = ENOMEM;
- return NULL;
- }
- memcpy(new_ptr, old_ptr, copy_size);
- LowLevelAlloc::Free(old_ptr);
- return new_ptr;
- }
- PERFTOOLS_DLL_DECL void *EmergencyCalloc(size_t n, size_t elem_size) {
- // Overflow check
- const size_t size = n * elem_size;
- if (elem_size != 0 && size / elem_size != n) return NULL;
- void *rv = EmergencyMalloc(size);
- if (rv != NULL) {
- memset(rv, 0, size);
- }
- return rv;
- }
- };
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