b4fda18d83
* changes: unwindstack: rename Memory::ReadPartially to Read. unwindstack: rename Memory::Read to ReadFully. unwindstack: add Memory::ReadPartially.
124 lines
3.4 KiB
C++
124 lines
3.4 KiB
C++
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <memory>
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#include <mutex>
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#include <string>
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#include <unwindstack/Elf.h>
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#include <unwindstack/MapInfo.h>
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#include <unwindstack/Maps.h>
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#include <unwindstack/Memory.h>
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namespace unwindstack {
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Memory* MapInfo::GetFileMemory() {
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std::unique_ptr<MemoryFileAtOffset> memory(new MemoryFileAtOffset);
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if (offset == 0) {
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if (memory->Init(name, 0)) {
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return memory.release();
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}
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return nullptr;
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}
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// There are two possibilities when the offset is non-zero.
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// - There is an elf file embedded in a file.
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// - The whole file is an elf file, and the offset needs to be saved.
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//
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// Map in just the part of the file for the map. If this is not
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// a valid elf, then reinit as if the whole file is an elf file.
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// If the offset is a valid elf, then determine the size of the map
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// and reinit to that size. This is needed because the dynamic linker
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// only maps in a portion of the original elf, and never the symbol
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// file data.
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uint64_t map_size = end - start;
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if (!memory->Init(name, offset, map_size)) {
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return nullptr;
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}
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bool valid;
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uint64_t max_size;
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Elf::GetInfo(memory.get(), &valid, &max_size);
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if (!valid) {
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// Init as if the whole file is an elf.
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if (memory->Init(name, 0)) {
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elf_offset = offset;
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return memory.release();
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}
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return nullptr;
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}
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if (max_size > map_size) {
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if (memory->Init(name, offset, max_size)) {
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return memory.release();
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}
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// Try to reinit using the default map_size.
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if (memory->Init(name, offset, map_size)) {
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return memory.release();
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}
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return nullptr;
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}
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return memory.release();
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}
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Memory* MapInfo::CreateMemory(const std::shared_ptr<Memory>& process_memory) {
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if (end <= start) {
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return nullptr;
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}
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elf_offset = 0;
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// Fail on device maps.
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if (flags & MAPS_FLAGS_DEVICE_MAP) {
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return nullptr;
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}
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// First try and use the file associated with the info.
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if (!name.empty()) {
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Memory* memory = GetFileMemory();
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if (memory != nullptr) {
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return memory;
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}
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}
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// If the map isn't readable, don't bother trying to read from process memory.
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if (!(flags & PROT_READ)) {
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return nullptr;
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}
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return new MemoryRange(process_memory, start, end - start, 0);
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}
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Elf* MapInfo::GetElf(const std::shared_ptr<Memory>& process_memory, bool init_gnu_debugdata) {
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// Make sure no other thread is trying to add the elf to this map.
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std::lock_guard<std::mutex> guard(mutex_);
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if (elf) {
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return elf;
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}
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elf = new Elf(CreateMemory(process_memory));
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elf->Init(init_gnu_debugdata);
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// If the init fails, keep the elf around as an invalid object so we
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// don't try to reinit the object.
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return elf;
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}
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} // namespace unwindstack
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