1 /*
2 * Copyright (C) 2018 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 DEBUG false // STOPSHIP if true
18 #include "config/ConfigKey.h"
19 #include "Log.h"
20
21 #include "src/statsd_config.pb.h" // Alert
22
23 #include <android-base/unique_fd.h>
24 #include <inttypes.h>
25 #include <sys/wait.h>
26
27 #include <string>
28
29 namespace {
30 const char kDropboxTag[] = "perfetto";
31 }
32
33 namespace android {
34 namespace os {
35 namespace statsd {
36
CollectPerfettoTraceAndUploadToDropbox(const PerfettoDetails & config,int64_t subscription_id,int64_t alert_id,const ConfigKey & configKey)37 bool CollectPerfettoTraceAndUploadToDropbox(const PerfettoDetails& config,
38 int64_t subscription_id,
39 int64_t alert_id,
40 const ConfigKey& configKey) {
41 VLOG("Starting trace collection through perfetto");
42
43 if (!config.has_trace_config()) {
44 ALOGE("The perfetto trace config is empty, aborting");
45 return false;
46 }
47
48 char subscriptionId[25];
49 char alertId[25];
50 char configId[25];
51 char configUid[25];
52 snprintf(subscriptionId, sizeof(subscriptionId), "%" PRId64, subscription_id);
53 snprintf(alertId, sizeof(alertId), "%" PRId64, alert_id);
54 snprintf(configId, sizeof(configId), "%" PRId64, configKey.GetId());
55 snprintf(configUid, sizeof(configUid), "%d", configKey.GetUid());
56
57 android::base::unique_fd readPipe;
58 android::base::unique_fd writePipe;
59 if (!android::base::Pipe(&readPipe, &writePipe)) {
60 ALOGE("pipe() failed while calling the Perfetto client: %s", strerror(errno));
61 return false;
62 }
63
64 pid_t pid = fork();
65 if (pid < 0) {
66 ALOGE("fork() failed while calling the Perfetto client: %s", strerror(errno));
67 return false;
68 }
69
70 if (pid == 0) {
71 // Child process.
72
73 // No malloc calls or library calls after this point. Remember that even
74 // ALOGx (aka android_printLog()) can use dynamic memory for vsprintf().
75
76 writePipe.reset(); // Close the write end (owned by the main process).
77
78 // Replace stdin with |readPipe| so the main process can write into it.
79 if (dup2(readPipe.get(), STDIN_FILENO) < 0) _exit(1);
80 readPipe.reset();
81
82 // Replace stdout/stderr with /dev/null and close any other file
83 // descriptor. This is to avoid SELinux complaining about perfetto
84 // trying to access files accidentally left open by statsd (i.e. files
85 // that have been opened without the O_CLOEXEC flag).
86 int devNullFd = open("/dev/null", O_RDWR | O_CLOEXEC);
87 if (dup2(devNullFd, STDOUT_FILENO) < 0) _exit(2);
88 if (dup2(devNullFd, STDERR_FILENO) < 0) _exit(3);
89 close(devNullFd);
90 for (int i = 0; i < 1024; i++) {
91 if (i != STDIN_FILENO && i != STDOUT_FILENO && i != STDERR_FILENO) close(i);
92 }
93
94 execl("/system/bin/perfetto", "perfetto", "--background", "--config", "-", "--dropbox",
95 kDropboxTag, "--alert-id", alertId, "--config-id", configId, "--config-uid",
96 configUid, "--subscription-id", subscriptionId, nullptr);
97
98 // execl() doesn't return in case of success, if we get here something
99 // failed.
100 _exit(4);
101 }
102
103 // Main process.
104
105 readPipe.reset(); // Close the read end (owned by the child process).
106
107 // Using fdopen() because fwrite() has the right logic to chunking write()
108 // over a pipe (see __sfvwrite()).
109 FILE* writePipeStream = android::base::Fdopen(std::move(writePipe), "wb");
110 if (!writePipeStream) {
111 ALOGE("fdopen() failed while calling the Perfetto client: %s", strerror(errno));
112 return false;
113 }
114
115 const std::string& cfgProto = config.trace_config();
116 size_t bytesWritten = fwrite(cfgProto.data(), 1, cfgProto.size(), writePipeStream);
117 fclose(writePipeStream);
118 if (bytesWritten != cfgProto.size() || cfgProto.size() == 0) {
119 ALOGE("fwrite() failed (ret: %zd) while calling the Perfetto client: %s", bytesWritten,
120 strerror(errno));
121 return false;
122 }
123
124 // This does NOT wait for the full duration of the trace. It just waits until
125 // the process has read the config from stdin and detached.
126 int childStatus = 0;
127 waitpid(pid, &childStatus, 0);
128 if (!WIFEXITED(childStatus) || WEXITSTATUS(childStatus) != 0) {
129 ALOGE("Child process failed (0x%x) while calling the Perfetto client", childStatus);
130 return false;
131 }
132
133 VLOG("CollectPerfettoTraceAndUploadToDropbox() succeeded");
134 return true;
135 }
136
137 } // namespace statsd
138 } // namespace os
139 } // namespace android
140