1 //
2 // Copyright (C) 2012 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 <inttypes.h>
18 #include <sys/stat.h>
19 #include <sys/types.h>
20 #include <unistd.h>
21 #include <xz.h>
22
23 #include <algorithm>
24 #include <string>
25 #include <vector>
26
27 #include <base/at_exit.h>
28 #include <base/command_line.h>
29 #include <base/files/dir_reader_posix.h>
30 #include <base/files/file_util.h>
31 #include <base/logging.h>
32 #include <base/strings/string_util.h>
33 #include <base/strings/stringprintf.h>
34 #include <brillo/flag_helper.h>
35
36 #include "update_engine/common/terminator.h"
37 #include "update_engine/common/utils.h"
38 #include "update_engine/daemon.h"
39
40 using std::string;
41
42 namespace chromeos_update_engine {
43 namespace {
44
GetTimeAsString(time_t utime)45 string GetTimeAsString(time_t utime) {
46 struct tm tm;
47 CHECK_EQ(localtime_r(&utime, &tm), &tm);
48 char str[16];
49 CHECK_EQ(strftime(str, sizeof(str), "%Y%m%d-%H%M%S", &tm), 15u);
50 return str;
51 }
52
53 #ifdef __ANDROID__
54 constexpr char kSystemLogsRoot[] = "/data/misc/update_engine_log";
55 constexpr size_t kLogCount = 5;
56
57 // Keep the most recent |kLogCount| logs but remove the old ones in
58 // "/data/misc/update_engine_log/".
DeleteOldLogs(const string & kLogsRoot)59 void DeleteOldLogs(const string& kLogsRoot) {
60 base::DirReaderPosix reader(kLogsRoot.c_str());
61 if (!reader.IsValid()) {
62 LOG(ERROR) << "Failed to read " << kLogsRoot;
63 return;
64 }
65
66 std::vector<string> old_logs;
67 while (reader.Next()) {
68 if (reader.name()[0] == '.')
69 continue;
70
71 // Log files are in format "update_engine.%Y%m%d-%H%M%S",
72 // e.g. update_engine.20090103-231425
73 uint64_t date;
74 uint64_t local_time;
75 if (sscanf(reader.name(),
76 "update_engine.%" PRIu64 "-%" PRIu64 "",
77 &date,
78 &local_time) == 2) {
79 old_logs.push_back(reader.name());
80 } else {
81 LOG(WARNING) << "Unrecognized log file " << reader.name();
82 }
83 }
84
85 std::sort(old_logs.begin(), old_logs.end(), std::greater<string>());
86 for (size_t i = kLogCount; i < old_logs.size(); i++) {
87 string log_path = kLogsRoot + "/" + old_logs[i];
88 if (unlink(log_path.c_str()) == -1) {
89 PLOG(WARNING) << "Failed to unlink " << log_path;
90 }
91 }
92 }
93
SetupLogFile(const string & kLogsRoot)94 string SetupLogFile(const string& kLogsRoot) {
95 DeleteOldLogs(kLogsRoot);
96
97 return base::StringPrintf("%s/update_engine.%s",
98 kLogsRoot.c_str(),
99 GetTimeAsString(::time(nullptr)).c_str());
100 }
101 #else
102 constexpr char kSystemLogsRoot[] = "/var/log";
103
SetupLogSymlink(const string & symlink_path,const string & log_path)104 void SetupLogSymlink(const string& symlink_path, const string& log_path) {
105 // TODO(petkov): To ensure a smooth transition between non-timestamped and
106 // timestamped logs, move an existing log to start the first timestamped
107 // one. This code can go away once all clients are switched to this version or
108 // we stop caring about the old-style logs.
109 if (utils::FileExists(symlink_path.c_str()) &&
110 !utils::IsSymlink(symlink_path.c_str())) {
111 base::ReplaceFile(
112 base::FilePath(symlink_path), base::FilePath(log_path), nullptr);
113 }
114 base::DeleteFile(base::FilePath(symlink_path), true);
115 if (symlink(log_path.c_str(), symlink_path.c_str()) == -1) {
116 PLOG(ERROR) << "Unable to create symlink " << symlink_path
117 << " pointing at " << log_path;
118 }
119 }
120
SetupLogFile(const string & kLogsRoot)121 string SetupLogFile(const string& kLogsRoot) {
122 const string kLogSymlink = kLogsRoot + "/update_engine.log";
123 const string kLogsDir = kLogsRoot + "/update_engine";
124 const string kLogPath =
125 base::StringPrintf("%s/update_engine.%s",
126 kLogsDir.c_str(),
127 GetTimeAsString(::time(nullptr)).c_str());
128 mkdir(kLogsDir.c_str(), 0755);
129 SetupLogSymlink(kLogSymlink, kLogPath);
130 return kLogSymlink;
131 }
132 #endif // __ANDROID__
133
SetupLogging(bool log_to_system,bool log_to_file)134 void SetupLogging(bool log_to_system, bool log_to_file) {
135 logging::LoggingSettings log_settings;
136 log_settings.lock_log = logging::DONT_LOCK_LOG_FILE;
137 log_settings.logging_dest = static_cast<logging::LoggingDestination>(
138 (log_to_system ? logging::LOG_TO_SYSTEM_DEBUG_LOG : 0) |
139 (log_to_file ? logging::LOG_TO_FILE : 0));
140 log_settings.log_file = nullptr;
141
142 string log_file;
143 if (log_to_file) {
144 log_file = SetupLogFile(kSystemLogsRoot);
145 log_settings.delete_old = logging::APPEND_TO_OLD_LOG_FILE;
146 log_settings.log_file = log_file.c_str();
147 }
148 logging::InitLogging(log_settings);
149
150 #ifdef __ANDROID__
151 // The log file will have AID_LOG as group ID; this GID is inherited from the
152 // parent directory "/data/misc/update_engine_log" which sets the SGID bit.
153 chmod(log_file.c_str(), 0640);
154 #endif
155 }
156
157 } // namespace
158 } // namespace chromeos_update_engine
159
main(int argc,char ** argv)160 int main(int argc, char** argv) {
161 DEFINE_bool(logtofile, false, "Write logs to a file in log_dir.");
162 DEFINE_bool(logtostderr,
163 false,
164 "Write logs to stderr instead of to a file in log_dir.");
165 DEFINE_bool(foreground, false, "Don't daemon()ize; run in foreground.");
166
167 chromeos_update_engine::Terminator::Init();
168 brillo::FlagHelper::Init(argc, argv, "A/B Update Engine");
169
170 // We have two logging flags "--logtostderr" and "--logtofile"; and the logic
171 // to choose the logging destination is:
172 // 1. --logtostderr --logtofile -> logs to both
173 // 2. --logtostderr -> logs to system debug
174 // 3. --logtofile or no flags -> logs to file
175 bool log_to_system = FLAGS_logtostderr;
176 bool log_to_file = FLAGS_logtofile || !FLAGS_logtostderr;
177 chromeos_update_engine::SetupLogging(log_to_system, log_to_file);
178 if (!FLAGS_foreground)
179 PLOG_IF(FATAL, daemon(0, 0) == 1) << "daemon() failed";
180
181 LOG(INFO) << "A/B Update Engine starting";
182
183 // xz-embedded requires to initialize its CRC-32 table once on startup.
184 xz_crc32_init();
185
186 // Ensure that all written files have safe permissions.
187 // This is a mask, so we _block_ all permissions for the group owner and other
188 // users but allow all permissions for the user owner. We allow execution
189 // for the owner so we can create directories.
190 // Done _after_ log file creation.
191 umask(S_IRWXG | S_IRWXO);
192
193 chromeos_update_engine::UpdateEngineDaemon update_engine_daemon;
194 int exit_code = update_engine_daemon.Run();
195
196 chromeos_update_engine::Subprocess::Get().FlushBufferedLogsAtExit();
197
198 LOG(INFO) << "A/B Update Engine terminating with exit code " << exit_code;
199 return exit_code;
200 }
201