1 /*
2  * Copyright 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 <debuggerd/client.h>
18 
19 #include <fcntl.h>
20 #include <stdio.h>
21 #include <sys/eventfd.h>
22 #include <unistd.h>
23 
24 #include <chrono>
25 #include <thread>
26 #include <vector>
27 
28 #include <gtest/gtest.h>
29 
30 #include <android-base/file.h>
31 #include <android-base/properties.h>
32 #include <android-base/stringprintf.h>
33 #include <android-base/strings.h>
34 #include <android-base/unique_fd.h>
35 
36 #include "util.h"
37 
38 using namespace std::chrono_literals;
39 using android::base::unique_fd;
40 
getThreadCount()41 static int getThreadCount() {
42   int threadCount = 1024;
43   std::vector<std::string> characteristics =
44       android::base::Split(android::base::GetProperty("ro.build.characteristics", ""), ",");
45   if (std::find(characteristics.begin(), characteristics.end(), "embedded")
46       != characteristics.end()) {
47     // 128 is the realistic number for iot devices.
48     threadCount = 128;
49   }
50   return threadCount;
51 }
52 
TEST(debuggerd_client,race)53 TEST(debuggerd_client, race) {
54   static int THREAD_COUNT = getThreadCount();
55 
56   // Semaphore incremented once per thread started.
57   unique_fd barrier(eventfd(0, EFD_SEMAPHORE));
58   ASSERT_NE(-1, barrier.get());
59 
60   pid_t forkpid = fork();
61   ASSERT_NE(-1, forkpid);
62   if (forkpid == 0) {
63     // Spawn a bunch of threads, to make crash_dump take longer.
64     std::vector<std::thread> threads;
65     threads.reserve(THREAD_COUNT);
66     for (int i = 0; i < THREAD_COUNT; ++i) {
67       threads.emplace_back([&barrier]() {
68         uint64_t count = 1;
69         ASSERT_NE(-1, write(barrier.get(), &count, sizeof(count)));
70         for (;;) {
71           pause();
72         }
73       });
74     }
75     for (;;) {
76       pause();
77     }
78   }
79 
80   // Wait for the child to spawn all of its threads.
81   for (int i = 0; i < THREAD_COUNT; ++i) {
82     uint64_t count;
83     ASSERT_NE(-1, read(barrier.get(), &count, sizeof(count)));
84   }
85 
86   unique_fd pipe_read, pipe_write;
87   ASSERT_TRUE(Pipe(&pipe_read, &pipe_write));
88 
89   // 16 MiB should be enough for everyone.
90   constexpr int PIPE_SIZE = 16 * 1024 * 1024;
91   ASSERT_EQ(PIPE_SIZE, fcntl(pipe_read.get(), F_SETPIPE_SZ, PIPE_SIZE));
92 
93   ASSERT_TRUE(
94       debuggerd_trigger_dump(forkpid, kDebuggerdNativeBacktrace, 60000, std::move(pipe_write)));
95   // Immediately kill the forked child, to make sure that the dump didn't return early.
96   ASSERT_EQ(0, kill(forkpid, SIGKILL)) << strerror(errno);
97 
98   // Check the output.
99   std::string result;
100   ASSERT_TRUE(android::base::ReadFdToString(pipe_read.get(), &result));
101 
102   // Look for "----- end <PID> -----"
103   int found_end = 0;
104 
105   std::string expected_end = android::base::StringPrintf("----- end %d -----", forkpid);
106 
107   std::vector<std::string> lines = android::base::Split(result, "\n");
108   for (const std::string& line : lines) {
109     if (line == expected_end) {
110       ++found_end;
111     }
112   }
113 
114   EXPECT_EQ(1, found_end) << "\nOutput: \n" << result;
115 }
116 
TEST(debuggerd_client,no_timeout)117 TEST(debuggerd_client, no_timeout) {
118   unique_fd pipe_read, pipe_write;
119   ASSERT_TRUE(Pipe(&pipe_read, &pipe_write));
120 
121   pid_t forkpid = fork();
122   ASSERT_NE(-1, forkpid);
123   if (forkpid == 0) {
124     pipe_write.reset();
125     char dummy;
126     TEMP_FAILURE_RETRY(read(pipe_read.get(), &dummy, sizeof(dummy)));
127     exit(0);
128   }
129 
130   pipe_read.reset();
131 
132   unique_fd output_read, output_write;
133   ASSERT_TRUE(Pipe(&output_read, &output_write));
134   ASSERT_TRUE(
135       debuggerd_trigger_dump(forkpid, kDebuggerdNativeBacktrace, 0, std::move(output_write)));
136 }
137