1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <sys/types.h>
18 #include <unistd.h>
19
20 #include <memory>
21 #include <string>
22
23 #include <unwindstack/Elf.h>
24 #include <unwindstack/MapInfo.h>
25 #include <unwindstack/Maps.h>
26 #include <unwindstack/Memory.h>
27
28 namespace unwindstack {
29
CreateMemory(pid_t pid)30 Memory* MapInfo::CreateMemory(pid_t pid) {
31 if (end <= start) {
32 return nullptr;
33 }
34
35 elf_offset = 0;
36
37 // First try and use the file associated with the info.
38 if (!name.empty()) {
39 // Fail on device maps.
40 if (flags & MAPS_FLAGS_DEVICE_MAP) {
41 return nullptr;
42 }
43
44 std::unique_ptr<MemoryFileAtOffset> file_memory(new MemoryFileAtOffset);
45 uint64_t map_size;
46 if (offset != 0) {
47 // Only map in a piece of the file.
48 map_size = end - start;
49 } else {
50 map_size = UINT64_MAX;
51 }
52 if (file_memory->Init(name, offset, map_size)) {
53 // It's possible that a non-zero offset might not be pointing to
54 // valid elf data. Check if this is a valid elf, and if not assume
55 // that this was meant to incorporate the entire file.
56 if (offset != 0 && !Elf::IsValidElf(file_memory.get())) {
57 // Don't bother checking the validity that will happen on the elf init.
58 if (file_memory->Init(name, 0)) {
59 elf_offset = offset;
60 return file_memory.release();
61 }
62 // Fall through if the init fails.
63 } else {
64 return file_memory.release();
65 }
66 }
67 }
68
69 Memory* memory = nullptr;
70 if (pid == getpid()) {
71 memory = new MemoryLocal();
72 } else {
73 memory = new MemoryRemote(pid);
74 }
75 return new MemoryRange(memory, start, end);
76 }
77
GetElf(pid_t pid,bool init_gnu_debugdata)78 Elf* MapInfo::GetElf(pid_t pid, bool init_gnu_debugdata) {
79 if (elf) {
80 return elf;
81 }
82
83 elf = new Elf(CreateMemory(pid));
84 if (elf->Init() && init_gnu_debugdata) {
85 elf->InitGnuDebugdata();
86 }
87 // If the init fails, keep the elf around as an invalid object so we
88 // don't try to reinit the object.
89 return elf;
90 }
91
92 } // namespace unwindstack
93