1 /*
2 * Copyright (C) 2019 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 #define _GNU_SOURCE 1
18 #include <stdint.h>
19 #include <string.h>
20
21 #include <string>
22
23 #if defined(__BIONIC__)
24
25 #include <gtest/gtest.h>
26
27 #include <unwindstack/AndroidUnwinder.h>
28 #include <unwindstack/DwarfSection.h>
29 #include <unwindstack/Elf.h>
30 #include <unwindstack/ElfInterface.h>
31
32 #include "ForkTest.h"
33
34 // This test is specific to bionic to verify that __libc_init is
35 // properly setting the return address to undefined so that the
36 // unwind properly terminates.
37
38 namespace unwindstack {
39
40 using VerifyBionicTermination = ForkTest;
41
DumpFrames(const AndroidUnwinderData & data,AndroidUnwinder & unwinder)42 static std::string DumpFrames(const AndroidUnwinderData& data, AndroidUnwinder& unwinder) {
43 // Init this way so that the first frame of the backtrace starts on a new line.
44 std::string unwind("\n");
45 for (auto& frame : data.frames) {
46 unwind += unwinder.FormatFrame(frame) + '\n';
47 }
48 return unwind;
49 }
50
GetReturnAddressLocation(uint64_t rel_pc,DwarfSection * section)51 static DwarfLocationEnum GetReturnAddressLocation(uint64_t rel_pc, DwarfSection* section) {
52 if (section == nullptr) {
53 return DWARF_LOCATION_INVALID;
54 }
55
56 const DwarfFde* fde = section->GetFdeFromPc(rel_pc);
57 if (fde == nullptr || fde->cie == nullptr) {
58 return DWARF_LOCATION_INVALID;
59 }
60 DwarfLocations regs;
61 if (!section->GetCfaLocationInfo(rel_pc, fde, ®s, ARCH_UNKNOWN)) {
62 return DWARF_LOCATION_INVALID;
63 }
64
65 auto reg_entry = regs.find(fde->cie->return_address_register);
66 if (reg_entry == regs.end()) {
67 return DWARF_LOCATION_INVALID;
68 }
69 return reg_entry->second.type;
70 }
71
VerifyReturnAddress(const FrameData & frame)72 static void VerifyReturnAddress(const FrameData& frame) {
73 // Now go and find information about the register data and verify that the relative pc results in
74 // an undefined register.
75 auto file_memory = Memory::CreateFileMemory(frame.map_info->name(), 0);
76 Elf elf(file_memory);
77 ASSERT_TRUE(frame.map_info != nullptr);
78 ASSERT_TRUE(elf.Init()) << "Failed to init elf object from " << frame.map_info->name().c_str();
79 ASSERT_TRUE(elf.valid()) << "Elf " << frame.map_info->name().c_str() << " is not valid.";
80 ElfInterface* interface = elf.interface();
81
82 // Only check the eh_frame and the debug_frame since the undefined register
83 // is set using a cfi directive.
84 // Check debug_frame first, then eh_frame since debug_frame always
85 // contains the most specific data.
86 DwarfLocationEnum location = GetReturnAddressLocation(frame.rel_pc, interface->debug_frame());
87 if (location == DWARF_LOCATION_UNDEFINED) {
88 return;
89 }
90
91 location = GetReturnAddressLocation(frame.rel_pc, interface->eh_frame());
92 ASSERT_EQ(DWARF_LOCATION_UNDEFINED, location);
93 }
94
95 // This assumes that the function starts from the main thread, and that the
96 // libc.so on device will include symbols so that function names can
97 // be resolved.
VerifyLibcInitTerminate(AndroidUnwinder & unwinder)98 static void VerifyLibcInitTerminate(AndroidUnwinder& unwinder) {
99 AndroidUnwinderData data;
100 ASSERT_TRUE(unwinder.Unwind(data));
101
102 SCOPED_TRACE(DumpFrames(data, unwinder));
103
104 // Look for the frame that includes __libc_init, there should only
105 // be one and it should be the last.
106 bool found = false;
107 const std::vector<FrameData>& frames = data.frames;
108 for (size_t i = 0; i < frames.size(); i++) {
109 const FrameData& frame = frames[i];
110 if (frame.function_name == "__libc_init" && frame.map_info != nullptr &&
111 !frame.map_info->name().empty() &&
112 std::string("libc.so") == basename(frame.map_info->name().c_str())) {
113 ASSERT_EQ(frames.size(), i + 1) << "__libc_init is not last frame.";
114 ASSERT_NO_FATAL_FAILURE(VerifyReturnAddress(frame));
115 found = true;
116 }
117 }
118 ASSERT_TRUE(found) << "Unable to find libc.so:__libc_init frame\n";
119 }
120
TEST_F(VerifyBionicTermination,local_terminate)121 TEST_F(VerifyBionicTermination, local_terminate) {
122 AndroidLocalUnwinder unwinder;
123 VerifyLibcInitTerminate(unwinder);
124 }
125
TEST_F(VerifyBionicTermination,remote_terminate)126 TEST_F(VerifyBionicTermination, remote_terminate) {
127 ASSERT_NO_FATAL_FAILURE(Fork());
128
129 AndroidRemoteUnwinder unwinder(pid_);
130 VerifyLibcInitTerminate(unwinder);
131 }
132
133 } // namespace unwindstack
134
135 #endif
136