1 /*
2 * Copyright (C) 2013 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 /*
18 * Contributed by: Intel Corporation
19 */
20
21 #include <gtest/gtest.h>
22
23 #include <dlfcn.h>
24 #include <signal.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <sys/types.h>
29 #include <unistd.h>
30 #include <unwind.h>
31
32 #include "SignalUtils.h"
33
34 #define noinline __attribute__((__noinline__))
35 #define __unused __attribute__((__unused__))
36
FrameCounter(_Unwind_Context * ctx __unused,void * arg)37 _Unwind_Reason_Code FrameCounter(_Unwind_Context* ctx __unused, void* arg) {
38 int* count_ptr = reinterpret_cast<int*>(arg);
39
40 #if SHOW_FRAME_LOCATIONS
41 void* ip = reinterpret_cast<void*>(_Unwind_GetIP(ctx));
42
43 const char* symbol = "<unknown>";
44 int offset = 0;
45
46 Dl_info info = {};
47 if (dladdr(ip, &info) != 0) {
48 symbol = info.dli_sname;
49 if (info.dli_saddr != nullptr) {
50 offset = static_cast<int>(reinterpret_cast<char*>(ip) - reinterpret_cast<char*>(info.dli_saddr));
51 }
52 }
53
54 fprintf(stderr, " #%02d %p %s%+d (%s)\n", *count_ptr, ip, symbol, offset, info.dli_fname ? info.dli_fname : "??");
55 fflush(stderr);
56 #endif
57
58 ++*count_ptr;
59 return _URC_NO_REASON;
60 }
61
unwind_one_frame_deeper()62 static int noinline unwind_one_frame_deeper() {
63 int count = 0;
64 _Unwind_Backtrace(FrameCounter, &count);
65 return count;
66 }
67
UnwindTest()68 static void UnwindTest() {
69 int count = 0;
70 _Unwind_Backtrace(FrameCounter, &count);
71 int deeper_count = unwind_one_frame_deeper();
72 ASSERT_EQ(count + 1, deeper_count);
73 }
74
TEST(stack_unwinding,easy)75 TEST(stack_unwinding, easy) {
76 UnwindTest();
77 }
78
TEST(stack_unwinding,thread)79 TEST(stack_unwinding, thread) {
80 pthread_t thread;
81 ASSERT_EQ(0, pthread_create(&thread, nullptr, [](void*) -> void* {
82 UnwindTest();
83 return nullptr;
84 }, nullptr));
85 void *retval;
86 ASSERT_EQ(0, pthread_join(thread, &retval));
87 EXPECT_EQ(nullptr, retval);
88 }
89
90 struct UnwindData {
91 volatile bool signal_handler_complete = false;
92 int expected_frame_count = 0;
93 int handler_frame_count = 0;
94 int handler_one_deeper_frame_count = 0;
95 };
96
97 static UnwindData g_unwind_data;
98
UnwindSignalHandler(int)99 static void noinline UnwindSignalHandler(int) {
100 _Unwind_Backtrace(FrameCounter, &g_unwind_data.handler_frame_count);
101
102 g_unwind_data.handler_one_deeper_frame_count = unwind_one_frame_deeper();
103 g_unwind_data.signal_handler_complete = true;
104 }
105
verify_unwind_data(const UnwindData & unwind_data)106 static void verify_unwind_data(const UnwindData& unwind_data) {
107 // In order to avoid a false positive, the caller must have at least 2 frames
108 // outside of the signal handler. This avoids a case where the only frame
109 // right after the signal handler winds up being garbage.
110 EXPECT_GT(unwind_data.handler_frame_count, unwind_data.expected_frame_count + 1);
111
112 EXPECT_EQ(unwind_data.handler_frame_count + 1, unwind_data.handler_one_deeper_frame_count);
113 }
114
SignalUnwindTest()115 static void noinline SignalUnwindTest() {
116 g_unwind_data = {};
117
118 _Unwind_Backtrace(FrameCounter, &g_unwind_data.expected_frame_count);
119 ASSERT_LE(2, g_unwind_data.expected_frame_count)
120 << "The current call must contain at least 2 frames for the test to be valid.";
121
122 ASSERT_EQ(0, kill(getpid(), SIGUSR1));
123 while (!g_unwind_data.signal_handler_complete) {}
124
125 verify_unwind_data(g_unwind_data);
126 }
127
TEST(stack_unwinding,unwind_through_signal_frame)128 TEST(stack_unwinding, unwind_through_signal_frame) {
129 ScopedSignalHandler ssh(SIGUSR1, UnwindSignalHandler);
130
131 SignalUnwindTest();
132 }
133
134 // On LP32, the SA_SIGINFO flag gets you __restore_rt instead of __restore.
TEST(stack_unwinding,unwind_through_signal_frame_SA_SIGINFO)135 TEST(stack_unwinding, unwind_through_signal_frame_SA_SIGINFO) {
136 ScopedSignalHandler ssh(SIGUSR1, UnwindSignalHandler, SA_SIGINFO);
137
138 SignalUnwindTest();
139 }
140