Peter Qiu | 5dd242d | 2014-10-14 12:23:21 -0700 | [diff] [blame^] | 1 | // Copyright 2014 The Chromium OS Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include <vector> |
| 6 | |
| 7 | #include <base/bind.h> |
| 8 | #include <base/command_line.h> |
| 9 | #include <base/logging.h> |
| 10 | #include <chromeos/minijail/minijail.h> |
| 11 | #include <chromeos/syslog_logging.h> |
| 12 | |
| 13 | #include "apmanager/daemon.h" |
| 14 | |
| 15 | using std::vector; |
| 16 | |
| 17 | namespace { |
| 18 | |
| 19 | namespace switches { |
| 20 | |
| 21 | // Don't daemon()ize; run in foreground. |
| 22 | const char kForeground[] = "foreground"; |
| 23 | // Flag that causes apmanager to show the help message and exit. |
| 24 | const char kHelp[] = "help"; |
| 25 | |
| 26 | // The help message shown if help flag is passed to the program. |
| 27 | const char kHelpMessage[] = "\n" |
| 28 | "Available Switches: \n" |
| 29 | " --foreground\n" |
| 30 | " Don\'t daemon()ize; run in foreground.\n"; |
| 31 | } // namespace switches |
| 32 | |
| 33 | } // namespace |
| 34 | |
| 35 | namespace { |
| 36 | |
| 37 | const char kLoggerCommand[] = "/usr/bin/logger"; |
| 38 | const char kLoggerUser[] = "syslog"; |
| 39 | |
| 40 | } // namespace |
| 41 | |
| 42 | // Always logs to the syslog and logs to stderr if |
| 43 | // we are running in the foreground. |
| 44 | void SetupLogging(chromeos::Minijail* minijail, |
| 45 | bool foreground, |
| 46 | const char* daemon_name) { |
| 47 | int log_flags = 0; |
| 48 | log_flags |= chromeos::kLogToSyslog; |
| 49 | log_flags |= chromeos::kLogHeader; |
| 50 | if (foreground) { |
| 51 | log_flags |= chromeos::kLogToStderr; |
| 52 | } |
| 53 | chromeos::InitLog(log_flags); |
| 54 | |
| 55 | if (!foreground) { |
| 56 | vector<char*> logger_command_line; |
| 57 | int logger_stdin_fd; |
| 58 | logger_command_line.push_back(const_cast<char*>(kLoggerCommand)); |
| 59 | logger_command_line.push_back(const_cast<char*>("--priority")); |
| 60 | logger_command_line.push_back(const_cast<char*>("daemon.err")); |
| 61 | logger_command_line.push_back(const_cast<char*>("--tag")); |
| 62 | logger_command_line.push_back(const_cast<char*>(daemon_name)); |
| 63 | logger_command_line.push_back(nullptr); |
| 64 | |
| 65 | struct minijail* jail = minijail->New(); |
| 66 | minijail->DropRoot(jail, kLoggerUser, kLoggerUser); |
| 67 | |
| 68 | if (!minijail->RunPipeAndDestroy(jail, logger_command_line, |
| 69 | nullptr, &logger_stdin_fd)) { |
| 70 | LOG(ERROR) << "Unable to spawn logger. " |
| 71 | << "Writes to stderr will be discarded."; |
| 72 | return; |
| 73 | } |
| 74 | |
| 75 | // Note that we don't set O_CLOEXEC here. This means that stderr |
| 76 | // from any child processes will, by default, be logged to syslog. |
| 77 | if (dup2(logger_stdin_fd, fileno(stderr)) != fileno(stderr)) { |
| 78 | LOG(ERROR) << "Failed to redirect stderr to syslog: " |
| 79 | << strerror(errno); |
| 80 | } |
| 81 | close(logger_stdin_fd); |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | void DropPrivileges(chromeos::Minijail* minijail) { |
| 86 | struct minijail* jail = minijail->New(); |
| 87 | minijail->DropRoot(jail, apmanager::Daemon::kAPManagerUserName, |
| 88 | apmanager::Daemon::kAPManagerGroupName); |
| 89 | minijail_enter(jail); |
| 90 | minijail->Destroy(jail); |
| 91 | } |
| 92 | |
| 93 | void OnStartup(const char* daemon_name, CommandLine* cl) { |
| 94 | chromeos::Minijail* minijail = chromeos::Minijail::GetInstance(); |
| 95 | SetupLogging(minijail, cl->HasSwitch(switches::kForeground), daemon_name); |
| 96 | |
| 97 | LOG(INFO) << __func__ << ": Dropping privileges"; |
| 98 | |
| 99 | // Now that the daemon has all the resources it needs to run, we can drop |
| 100 | // privileges further. |
| 101 | DropPrivileges(minijail); |
| 102 | } |
| 103 | |
| 104 | int main(int argc, char* argv[]) { |
| 105 | CommandLine::Init(argc, argv); |
| 106 | CommandLine* cl = CommandLine::ForCurrentProcess(); |
| 107 | |
| 108 | if (cl->HasSwitch(switches::kHelp)) { |
| 109 | LOG(INFO) << switches::kHelpMessage; |
| 110 | return 0; |
| 111 | } |
| 112 | |
| 113 | const int nochdir = 0, noclose = 0; |
| 114 | if (!cl->HasSwitch(switches::kForeground)) |
| 115 | PLOG_IF(FATAL, daemon(nochdir, noclose) == -1) << "Failed to daemonize"; |
| 116 | |
| 117 | apmanager::Daemon daemon(base::Bind(&OnStartup, argv[0], cl)); |
| 118 | |
| 119 | daemon.Run(); |
| 120 | |
| 121 | return 0; |
| 122 | } |