5f118519fd
New function to create the process memory object. This allows for a future where different remote process memory objects could be created depending on the way remote memory can be created. Even different local memory objects that access memory without doing any checks. It also allows MemoryRange objects to share one single process memory object and could help if the process memory object caches data. Small changes to MapInfo::CreateMemory to when some errors are detected. - Always check if the map is a device map, instead of only if the name is not empty. - Check if a memory map is readable before creating the memory from process memory. Bug: 23762183 Test: Ran unit tests, unwound on device using the new code. Change-Id: I12a93c2dc19639689a528ec41c67bfac74d431b3
121 lines
3.3 KiB
C++
121 lines
3.3 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 <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);
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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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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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if (elf->Init() && init_gnu_debugdata) {
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elf->InitGnuDebugdata();
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}
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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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