11 #include <sys/socket.h>
19 #include "dinit-log.h"
23 #include <sys/reboot.h>
27 * "simpleinit" from util-linux-ng package handles signals as follows:
28 * SIGTSTP - spawn no more gettys (in preparation for shutdown etc).
29 * In dinit terms this should probably mean "no more auto restarts"
30 * (for any service). (Actually the signal acts as a toggle, if
31 * respawn is disabled it will be re-enabled and init will
32 * act as if SIGHUP had also been sent)
33 * SIGTERM - kill spawned gettys (which are still alive)
34 * Interestingly, simpleinit just sends a SIGTERM to the gettys,
35 * which will not normall kill shells (eg bash ignores SIGTERM).
36 * "/sbin/initctl -r" - rollback services (ran by "shutdown"/halt etc);
37 * shouldn't return until all services have been stopped.
38 * shutdown calls this after sending SIGTERM to processes running
39 * with uid >= 100 ("mortals").
40 * SIGQUIT - init will exec() shutdown. shutdown will detect that it is
41 * running as pid 1 and will just loop and reap child processes.
42 * This is used by shutdown so that init will not hang on to its
43 * inode, allowing the filesystem to be re-mounted readonly
44 * (this is only an issue if the init binary has been unlinked,
45 * since it's then holding an inode which can't be maintained
46 * when the filesystem is unmounted).
48 * Not sent by shutdown:
49 * SIGHUP - re-read inittab and spawn any new getty entries
50 * SIGINT - (ctrl+alt+del handler) - fork & exec "reboot"
52 * On the contrary dinit currently uses:
53 * SIGTERM - roll back services and then fork/exec /sbin/halt
54 * SIGINT - roll back services and then fork/exec /sbin/reboot
55 * SIGQUIT - exec() /sbin/shutdown as per above.
57 * It's an open question about whether dinit should roll back services *before*
58 * running halt/reboot, since those commands should prompt rollback of services
59 * anyway. But it seems safe to do so.
63 using namespace dasynq;
64 using EventLoop_t = EventLoop<NullMutex>;
66 EventLoop_t eventLoop = EventLoop_t();
68 static void sigint_reboot_cb(EventLoop_t *eloop) noexcept;
69 static void sigquit_cb(EventLoop_t *eloop) noexcept;
70 static void sigterm_cb(EventLoop_t *eloop) noexcept;
71 static void close_control_socket() noexcept;
73 static void control_socket_cb(EventLoop_t *loop, int fd);
75 void open_control_socket(bool report_ro_failure = true) noexcept;
76 void setup_external_log() noexcept;
79 class ControlSocketWatcher : public EventLoop_t::FdWatcher
81 Rearm fdEvent(EventLoop_t &loop, int fd, int flags) override
83 control_socket_cb(&loop, fd);
88 // TODO the fd is already stored, must we really store it again...
91 void addWatch(EventLoop_t &loop, int fd, int flags)
94 EventLoop_t::FdWatcher::addWatch(loop, fd, flags);
98 ControlSocketWatcher control_socket_io;
103 static ServiceSet *service_set;
105 static bool am_system_init = false; // true if we are the system init process
107 static bool control_socket_open = false;
108 static bool external_log_open = false;
109 int active_control_conns = 0;
111 // Control socket path. We maintain a string (control_socket_str) in case we need
112 // to allocate storage, but control_socket_path is the authoritative value.
113 static const char *control_socket_path = "/dev/dinitctl";
114 static std::string control_socket_str;
116 static const char *log_socket_path = "/dev/log";
118 static const char *user_home_path = nullptr;
121 // Get user home (and set user_home_path). (The return may become invalid after
122 // changing the evironment (HOME variable) or using the getpwuid() function).
123 const char * get_user_home()
125 if (user_home_path == nullptr) {
126 user_home_path = getenv("HOME");
127 if (user_home_path == nullptr) {
128 struct passwd * pwuid_p = getpwuid(getuid());
129 if (pwuid_p != nullptr) {
130 user_home_path = pwuid_p->pw_dir;
134 return user_home_path;
139 class CallbackSignalHandler : public EventLoop_t::SignalWatcher
142 typedef void (*cb_func_t)(EventLoop_t *);
148 CallbackSignalHandler() : cb_func(nullptr) { }
149 CallbackSignalHandler(cb_func_t pcb_func) : cb_func(pcb_func) { }
151 void setCbFunc(cb_func_t cb_func)
153 this->cb_func = cb_func;
156 Rearm received(EventLoop_t &eloop, int signo, SigInfo_p siginfo) override
158 service_set->stop_all_services(ShutdownType::REBOOT);
163 class ControlSocketWatcher : public EventLoop_t::FdWatcher
165 Rearm fdEvent(EventLoop_t &loop, int fd, int flags)
167 control_socket_cb(&loop, fd);
173 int main(int argc, char **argv)
177 am_system_init = (getpid() == 1);
178 const char * service_dir = nullptr;
179 string service_dir_str; // to hold storage for above if necessary
180 bool control_socket_path_set = false;
182 // list of services to start
183 list<const char *> services_to_start;
185 // Arguments, if given, specify a list of services to start.
186 // If we are running as init (PID=1), the kernel gives us any command line
187 // arguments it was given but didn't recognize, including "single" (usually
188 // for "boot to single user mode" aka just start the shell). We can treat
189 // them as service names. In the worst case we can't find any of the named
190 // services, and so we'll start the "boot" service by default.
192 for (int i = 1; i < argc; i++) {
193 if (argv[i][0] == '-') {
195 if (strcmp(argv[i], "--services-dir") == 0 ||
196 strcmp(argv[i], "-d") == 0) {
198 service_dir = argv[i];
201 cerr << "dinit: '--services-dir' (-d) requires an argument" << endl;
205 else if (strcmp(argv[i], "--system") == 0 ||
206 strcmp(argv[i], "-s") == 0) {
207 am_system_init = true;
209 else if (strcmp(argv[i], "--socket-path") == 0 ||
210 strcmp(argv[i], "-p") == 0) {
212 control_socket_path = argv[i];
213 control_socket_path_set = true;
216 cerr << "dinit: '--socket-path' (-p) requires an argument" << endl;
220 else if (strcmp(argv[i], "--help") == 0) {
221 cout << "dinit, an init with dependency management" << endl;
222 cout << " --help display help" << endl;
223 cout << " --services-dir <dir>, -d <dir>" << endl;
224 cout << " set base directory for service description" << endl;
225 cout << " files (-d <dir>)" << endl;
226 cout << " --system, -s run as the system init process" << endl;
227 cout << " --socket-path <path>, -p <path>" << endl;
228 cout << " path to control socket" << endl;
229 cout << " <service-name> start service with name <service-name>" << endl;
234 if (! am_system_init) {
235 cerr << "dinit: Unrecognized option: " << argv[i] << endl;
241 // LILO puts "auto" on the kernel command line for unattended boots; we'll filter it.
242 if (! am_system_init || strcmp(argv[i], "auto") != 0) {
243 services_to_start.push_back(argv[i]);
249 if (am_system_init) {
250 // setup STDIN, STDOUT, STDERR so that we can use them
251 int onefd = open("/dev/console", O_RDONLY, 0);
253 int twofd = open("/dev/console", O_RDWR, 0);
257 if (onefd > 2) close(onefd);
258 if (twofd > 2) close(twofd);
261 /* Set up signal handlers etc */
262 /* SIG_CHILD is ignored by default: good */
263 sigset_t sigwait_set;
264 sigemptyset(&sigwait_set);
265 sigaddset(&sigwait_set, SIGCHLD);
266 sigaddset(&sigwait_set, SIGINT);
267 sigaddset(&sigwait_set, SIGTERM);
268 sigprocmask(SIG_BLOCK, &sigwait_set, NULL);
270 // Terminal access control signals - we block these so that dinit can't be
271 // suspended if it writes to the terminal after some other process has claimed
273 signal(SIGTSTP, SIG_IGN);
274 signal(SIGTTIN, SIG_IGN);
275 signal(SIGTTOU, SIG_IGN);
277 if (! am_system_init && ! control_socket_path_set) {
278 const char * userhome = get_user_home();
279 if (userhome != nullptr) {
280 control_socket_str = userhome;
281 control_socket_str += "/.dinitctl";
282 control_socket_path = control_socket_str.c_str();
286 /* service directory name */
287 if (service_dir == nullptr && ! am_system_init) {
288 const char * userhome = get_user_home();
289 if (userhome != nullptr) {
290 service_dir_str = get_user_home();
291 service_dir_str += "/dinit.d";
292 service_dir = service_dir_str.c_str();
296 if (service_dir == nullptr) {
297 service_dir = "/etc/dinit.d";
300 if (services_to_start.empty()) {
301 services_to_start.push_back("boot");
304 // Set up signal handlers
305 CallbackSignalHandler sigint_watcher;
306 if (am_system_init) {
307 sigint_watcher.setCbFunc(sigint_reboot_cb);
310 sigint_watcher.setCbFunc(sigterm_cb);
313 CallbackSignalHandler sigquit_watcher;
314 if (am_system_init) {
315 // PID 1: SIGQUIT exec's shutdown
316 sigquit_watcher.setCbFunc(sigquit_cb);
319 // Otherwise: SIGQUIT terminates dinit
320 sigquit_watcher.setCbFunc(sigterm_cb);
323 auto sigterm_watcher = CallbackSignalHandler(sigterm_cb);
325 sigint_watcher.addWatch(eventLoop, SIGINT);
326 sigquit_watcher.addWatch(eventLoop, SIGQUIT);
327 sigterm_watcher.addWatch(eventLoop, SIGTERM);
329 // Try to open control socket (may fail due to readonly filesystem)
330 open_control_socket(false);
333 if (am_system_init) {
334 // Disable non-critical kernel output to console
335 klogctl(6 /* SYSLOG_ACTION_CONSOLE_OFF */, nullptr, 0);
336 // Make ctrl+alt+del combination send SIGINT to PID 1 (this process)
337 reboot(RB_DISABLE_CAD);
341 /* start requested services */
342 service_set = new ServiceSet(service_dir);
344 init_log(service_set);
346 for (list<const char *>::iterator i = services_to_start.begin();
347 i != services_to_start.end();
350 service_set->startService(*i);
352 catch (ServiceNotFound &snf) {
353 log(LogLevel::ERROR, snf.serviceName, ": Could not find service description.");
355 catch (ServiceLoadExc &sle) {
356 log(LogLevel::ERROR, sle.serviceName, ": ", sle.excDescription);
358 catch (std::bad_alloc &badalloce) {
359 log(LogLevel::ERROR, "Out of memory when trying to start service: ", *i, ".");
365 // Process events until all services have terminated.
366 while (service_set->count_active_services() != 0) {
370 ShutdownType shutdown_type = service_set->getShutdownType();
372 if (am_system_init) {
373 logMsgBegin(LogLevel::INFO, "No more active services.");
375 if (shutdown_type == ShutdownType::REBOOT) {
376 logMsgEnd(" Will reboot.");
378 else if (shutdown_type == ShutdownType::HALT) {
379 logMsgEnd(" Will halt.");
381 else if (shutdown_type == ShutdownType::POWEROFF) {
382 logMsgEnd(" Will power down.");
385 logMsgEnd(" Re-initiating boot sequence.");
389 while (! is_log_flushed()) {
393 close_control_socket();
395 if (am_system_init) {
396 if (shutdown_type == ShutdownType::CONTINUE) {
397 // It could be that we started in single user mode, and the
398 // user has now exited the shell. We'll try and re-start the
401 service_set->startService("boot");
402 goto event_loop; // yes, the "evil" goto
405 // Now WTF do we do? try to reboot
406 log(LogLevel::ERROR, "Could not start 'boot' service; rebooting.");
407 shutdown_type = ShutdownType::REBOOT;
411 const char * cmd_arg;
412 if (shutdown_type == ShutdownType::HALT) {
415 else if (shutdown_type == ShutdownType::REBOOT) {
423 // Fork and execute dinit-reboot.
424 execl("/sbin/shutdown", "/sbin/shutdown", "--system", cmd_arg, nullptr);
425 log(LogLevel::ERROR, "Could not execute /sbin/shutdown: ", strerror(errno));
427 // PID 1 must not actually exit, although we should never reach this point:
436 // Callback for control socket
437 static void control_socket_cb(EventLoop_t *loop, int sockfd)
439 // TODO limit the number of active connections. Keep a tally, and disable the
440 // control connection listening socket watcher if it gets high, and re-enable
441 // it once it falls below the maximum.
443 // Accept a connection
444 int newfd = accept4(sockfd, nullptr, nullptr, SOCK_NONBLOCK | SOCK_CLOEXEC);
448 new ControlConn(loop, service_set, newfd); // will delete itself when it's finished
450 catch (std::exception &exc) {
451 log(LogLevel::ERROR, "Accepting control connection: ", exc.what());
457 void open_control_socket(bool report_ro_failure) noexcept
459 if (! control_socket_open) {
460 const char * saddrname = control_socket_path;
461 uint sockaddr_size = offsetof(struct sockaddr_un, sun_path) + strlen(saddrname) + 1;
463 struct sockaddr_un * name = static_cast<sockaddr_un *>(malloc(sockaddr_size));
464 if (name == nullptr) {
465 log(LogLevel::ERROR, "Opening control socket: out of memory");
469 if (am_system_init) {
470 // Unlink any stale control socket file, but only if we are system init, since otherwise
471 // the 'stale' file may not be stale at all:
475 name->sun_family = AF_UNIX;
476 strcpy(name->sun_path, saddrname);
478 // OpenBSD and Linux both allow combining NONBLOCK/CLOEXEC flags with socket type, however
479 // it's not actually POSIX. (TODO).
480 int sockfd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
482 log(LogLevel::ERROR, "Error creating control socket: ", strerror(errno));
487 if (bind(sockfd, (struct sockaddr *) name, sockaddr_size) == -1) {
488 if (errno != EROFS || report_ro_failure) {
489 log(LogLevel::ERROR, "Error binding control socket: ", strerror(errno));
498 // No connections can be made until we listen, so it is fine to change the permissions now
499 // (and anyway there is no way to atomically create the socket and set permissions):
500 if (chmod(saddrname, S_IRUSR | S_IWUSR) == -1) {
501 log(LogLevel::ERROR, "Error setting control socket permissions: ", strerror(errno));
506 if (listen(sockfd, 10) == -1) {
507 log(LogLevel::ERROR, "Error listening on control socket: ", strerror(errno));
513 control_socket_io.addWatch(eventLoop, sockfd, IN_EVENTS);
514 control_socket_open = true;
516 catch (std::exception &e)
518 log(LogLevel::ERROR, "Could not setup I/O on control socket: ", e.what());
524 static void close_control_socket() noexcept
526 if (control_socket_open) {
527 int fd = control_socket_io.fd;
528 control_socket_io.deregister(eventLoop);
531 // Unlink the socket:
532 unlink(control_socket_path);
536 void setup_external_log() noexcept
538 if (! external_log_open) {
540 const char * saddrname = log_socket_path;
541 uint sockaddr_size = offsetof(struct sockaddr_un, sun_path) + strlen(saddrname) + 1;
543 struct sockaddr_un * name = static_cast<sockaddr_un *>(malloc(sockaddr_size));
544 if (name == nullptr) {
545 log(LogLevel::ERROR, "Connecting to log socket: out of memory");
549 name->sun_family = AF_UNIX;
550 strcpy(name->sun_path, saddrname);
552 int sockfd = socket(AF_UNIX, SOCK_DGRAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
554 log(LogLevel::ERROR, "Error creating log socket: ", strerror(errno));
559 if (connect(sockfd, (struct sockaddr *) name, sockaddr_size) == 0 || errno == EINPROGRESS) {
560 // TODO for EINPROGRESS, set up a watcher so we can properly wait until
561 // connection is established (or fails) before we pass it to the logging subsystem.
563 setup_main_log(sockfd);
565 catch (std::exception &e) {
566 log(LogLevel::ERROR, "Setting up log failed: ", e.what());
571 // Note if connect fails, we haven't warned at all, because the syslog server might not
572 // have started yet. TODO, have a special startup flag to indicate when syslog should
581 /* handle SIGINT signal (generated by kernel when ctrl+alt+del pressed) */
582 static void sigint_reboot_cb(EventLoop_t *eloop) noexcept
584 service_set->stop_all_services(ShutdownType::REBOOT);
587 /* handle SIGQUIT (if we are system init) */
588 static void sigquit_cb(EventLoop_t *eloop) noexcept
590 // This allows remounting the filesystem read-only if the dinit binary has been
591 // unlinked. In that case the kernel holds the binary open, so that it can't be
593 close_control_socket();
594 execl("/sbin/shutdown", "/sbin/shutdown", (char *) 0);
595 log(LogLevel::ERROR, "Error executing /sbin/shutdown: ", strerror(errno));
598 /* handle SIGTERM/SIGQUIT - stop all services (not used for system daemon) */
599 static void sigterm_cb(EventLoop_t *eloop) noexcept
601 service_set->stop_all_services();