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 dasync;
64 using EventLoop_t = EventLoop<NullMutex>;
66 EventLoop_t eventLoop = EventLoop_t();
69 //static void sigint_reboot_cb(struct ev_loop *loop, ev_signal *w, int revents);
70 //static void sigquit_cb(struct ev_loop *loop, ev_signal *w, int revents);
71 //static void sigterm_cb(struct ev_loop *loop, ev_signal *w, int revents);
72 static void sigint_reboot_cb(EventLoop_t *eloop) noexcept;
73 static void sigquit_cb(EventLoop_t *eloop) noexcept;
74 static void sigterm_cb(EventLoop_t *eloop) noexcept;
75 void open_control_socket(EventLoop_t *loop) noexcept;
76 void close_control_socket(EventLoop_t *loop) noexcept;
78 static void control_socket_cb(EventLoop_t *loop, int fd);
80 class ControlSocketWatcher : public PosixFdWatcher<NullMutex>
82 Rearm gotEvent(EventLoop_t * loop, int fd, int flags)
84 control_socket_cb(loop, fd);
89 // TODO the fd is already stored, must we really store it again...
92 void registerWith(EventLoop_t * loop, int fd, int flags)
95 PosixFdWatcher<NullMutex>::registerWith(loop, fd, flags);
99 ControlSocketWatcher control_socket_io;
104 static ServiceSet *service_set;
106 static bool am_system_init = false; // true if we are the system init process
108 static bool control_socket_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 *user_home_path = nullptr;
119 // Get user home (and set user_home_path). (The return may become invalid after
120 // changing the evironment (HOME variable) or using the getpwuid() function).
121 const char * get_user_home()
123 if (user_home_path == nullptr) {
124 user_home_path = getenv("HOME");
125 if (user_home_path == nullptr) {
126 struct passwd * pwuid_p = getpwuid(getuid());
127 if (pwuid_p != nullptr) {
128 user_home_path = pwuid_p->pw_dir;
132 return user_home_path;
137 class CallbackSignalHandler : public PosixSignalWatcher<NullMutex>
140 typedef void (*cb_func_t)(EventLoop_t *);
146 CallbackSignalHandler() : cb_func(nullptr) { }
147 CallbackSignalHandler(cb_func_t pcb_func) : cb_func(pcb_func) { }
149 void setCbFunc(cb_func_t cb_func)
151 this->cb_func = cb_func;
154 Rearm gotSignal(EventLoop_t * eloop, int signo, SigInfo_p siginfo) override
156 service_set->stop_all_services(ShutdownType::REBOOT);
161 class ControlSocketWatcher : public PosixFdWatcher<NullMutex>
163 Rearm gotEvent(EventLoop_t * loop, int fd, int flags)
165 control_socket_cb(loop, fd);
171 int main(int argc, char **argv)
175 am_system_init = (getpid() == 1);
176 const char * service_dir = nullptr;
177 string service_dir_str; // to hold storage for above if necessary
178 bool control_socket_path_set = false;
180 // list of services to start
181 list<const char *> services_to_start;
183 // Arguments, if given, specify a list of services to start.
184 // If we are running as init (PID=1), the kernel gives us any command line
185 // arguments it was given but didn't recognize, including "single" (usually
186 // for "boot to single user mode" aka just start the shell). We can treat
187 // them as service names. In the worst case we can't find any of the named
188 // services, and so we'll start the "boot" service by default.
190 for (int i = 1; i < argc; i++) {
191 if (argv[i][0] == '-') {
193 if (strcmp(argv[i], "--services-dir") == 0 ||
194 strcmp(argv[i], "-d") == 0) {
196 service_dir = argv[i];
199 cerr << "dinit: '--services-dir' (-d) requires an argument" << endl;
203 else if (strcmp(argv[i], "--system") == 0 ||
204 strcmp(argv[i], "-s") == 0) {
205 am_system_init = true;
207 else if (strcmp(argv[i], "--socket-path") == 0 ||
208 strcmp(argv[i], "-p") == 0) {
210 control_socket_path = argv[i];
211 control_socket_path_set = true;
214 cerr << "dinit: '--socket-path' (-p) requires an argument" << endl;
218 else if (strcmp(argv[i], "--help") == 0) {
219 cout << "dinit, an init with dependency management" << endl;
220 cout << " --help display help" << endl;
221 cout << " --services-dir <dir>, -d <dir>" << endl;
222 cout << " set base directory for service description" << endl;
223 cout << " files (-d <dir>)" << endl;
224 cout << " --system, -s run as the system init process" << endl;
225 cout << " --socket-path <path>, -p <path>" << endl;
226 cout << " path to control socket" << endl;
227 cout << " <service-name> start service with name <service-name>" << endl;
232 if (! am_system_init) {
233 cerr << "dinit: Unrecognized option: " << argv[i] << endl;
239 // LILO puts "auto" on the kernel command line for unattended boots; we'll filter it.
240 if (! am_system_init || strcmp(argv[i], "auto") != 0) {
241 services_to_start.push_back(argv[i]);
247 if (am_system_init) {
248 // setup STDIN, STDOUT, STDERR so that we can use them
249 int onefd = open("/dev/console", O_RDONLY, 0);
251 int twofd = open("/dev/console", O_RDWR, 0);
255 if (onefd > 2) close(onefd);
256 if (twofd > 2) close(twofd);
259 /* Set up signal handlers etc */
260 /* SIG_CHILD is ignored by default: good */
261 sigset_t sigwait_set;
262 sigemptyset(&sigwait_set);
263 sigaddset(&sigwait_set, SIGCHLD);
264 sigaddset(&sigwait_set, SIGINT);
265 sigaddset(&sigwait_set, SIGTERM);
266 sigprocmask(SIG_BLOCK, &sigwait_set, NULL);
268 // Terminal access control signals - we block these so that dinit can't be
269 // suspended if it writes to the terminal after some other process has claimed
271 signal(SIGTSTP, SIG_IGN);
272 signal(SIGTTIN, SIG_IGN);
273 signal(SIGTTOU, SIG_IGN);
275 if (! am_system_init && ! control_socket_path_set) {
276 const char * userhome = get_user_home();
277 if (userhome != nullptr) {
278 control_socket_str = userhome;
279 control_socket_str += "/.dinitctl";
280 control_socket_path = control_socket_str.c_str();
284 /* service directory name */
285 if (service_dir == nullptr && ! am_system_init) {
286 const char * userhome = get_user_home();
287 if (userhome != nullptr) {
288 service_dir_str = get_user_home();
289 service_dir_str += "/dinit.d";
290 service_dir = service_dir_str.c_str();
294 if (service_dir == nullptr) {
295 service_dir = "/etc/dinit.d";
298 if (services_to_start.empty()) {
299 services_to_start.push_back("boot");
302 // Set up signal handlers
303 //ev_signal sigint_ev_signal;
304 CallbackSignalHandler sigint_watcher;
305 if (am_system_init) {
306 sigint_watcher.setCbFunc(sigint_reboot_cb);
309 sigint_watcher.setCbFunc(sigterm_cb);
312 CallbackSignalHandler sigquit_watcher;
313 if (am_system_init) {
314 // PID 1: SIGQUIT exec's shutdown
315 sigquit_watcher.setCbFunc(sigquit_cb);
318 // Otherwise: SIGQUIT terminates dinit
319 sigquit_watcher.setCbFunc(sigterm_cb);
322 auto sigterm_watcher = CallbackSignalHandler(sigterm_cb);
324 sigint_watcher.registerWatch(&eventLoop, SIGINT);
325 sigquit_watcher.registerWatch(&eventLoop, SIGQUIT);
326 sigterm_watcher.registerWatch(&eventLoop, SIGTERM);
328 // Try to open control socket (may fail due to readonly filesystem)
329 open_control_socket(&eventLoop);
332 if (am_system_init) {
333 // Disable non-critical kernel output to console
334 klogctl(6 /* SYSLOG_ACTION_CONSOLE_OFF */, nullptr, 0);
335 // Make ctrl+alt+del combination send SIGINT to PID 1 (this process)
336 reboot(RB_DISABLE_CAD);
340 /* start requested services */
341 service_set = new ServiceSet(service_dir);
343 init_log(service_set);
345 for (list<const char *>::iterator i = services_to_start.begin();
346 i != services_to_start.end();
349 service_set->startService(*i);
351 catch (ServiceNotFound &snf) {
352 log(LogLevel::ERROR, snf.serviceName, ": Could not find service description.");
354 catch (ServiceLoadExc &sle) {
355 log(LogLevel::ERROR, sle.serviceName, ": ", sle.excDescription);
357 catch (std::bad_alloc &badalloce) {
358 log(LogLevel::ERROR, "Out of memory when trying to start service: ", *i, ".");
364 // Process events until all services have terminated.
365 while (service_set->count_active_services() != 0) {
369 ShutdownType shutdown_type = service_set->getShutdownType();
371 if (am_system_init) {
372 logMsgBegin(LogLevel::INFO, "No more active services.");
374 if (shutdown_type == ShutdownType::REBOOT) {
375 logMsgEnd(" Will reboot.");
377 else if (shutdown_type == ShutdownType::HALT) {
378 logMsgEnd(" Will halt.");
380 else if (shutdown_type == ShutdownType::POWEROFF) {
381 logMsgEnd(" Will power down.");
384 logMsgEnd(" Re-initiating boot sequence.");
388 while (! is_log_flushed()) {
392 close_control_socket(&eventLoop);
394 if (am_system_init) {
395 if (shutdown_type == ShutdownType::CONTINUE) {
396 // It could be that we started in single user mode, and the
397 // user has now exited the shell. We'll try and re-start the
400 service_set->startService("boot");
401 goto event_loop; // yes, the "evil" goto
404 // Now WTF do we do? try to reboot
405 log(LogLevel::ERROR, "Could not start 'boot' service; rebooting.");
406 shutdown_type = ShutdownType::REBOOT;
410 const char * cmd_arg;
411 if (shutdown_type == ShutdownType::HALT) {
414 else if (shutdown_type == ShutdownType::REBOOT) {
422 // Fork and execute dinit-reboot.
423 execl("/sbin/shutdown", "/sbin/shutdown", "--system", cmd_arg, nullptr);
424 log(LogLevel::ERROR, "Could not execute /sbin/shutdown: ", strerror(errno));
426 // PID 1 must not actually exit, although we should never reach this point:
428 // ev_loop(loop, EVLOOP_ONESHOT);
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::bad_alloc &bad_alloc_exc) {
451 log(LogLevel::ERROR, "Accepting control connection: Out of memory");
457 void open_control_socket(EventLoop_t *loop) 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 log(LogLevel::ERROR, "Error binding control socket: ", strerror(errno));
496 // No connections can be made until we listen, so it is fine to change the permissions now
497 // (and anyway there is no way to atomically create the socket and set permissions):
498 if (chmod(saddrname, S_IRUSR | S_IWUSR) == -1) {
499 log(LogLevel::ERROR, "Error setting control socket permissions: ", strerror(errno));
504 if (listen(sockfd, 10) == -1) {
505 log(LogLevel::ERROR, "Error listening on control socket: ", strerror(errno));
510 control_socket_open = true;
511 //ev_io_init(&control_socket_io, control_socket_cb, sockfd, EV_READ);
512 //ev_io_start(loop, &control_socket_io);
513 control_socket_io.registerWith(&eventLoop, sockfd, in_events);
517 void close_control_socket(EventLoop_t *loop) noexcept
519 if (control_socket_open) {
520 int fd = control_socket_io.fd;
521 //ev_io_stop(loop, &control_socket_io);
522 control_socket_io.deregisterWatch(&eventLoop);
525 // Unlink the socket:
526 unlink(control_socket_path);
530 /* handle SIGINT signal (generated by kernel when ctrl+alt+del pressed) */
531 static void sigint_reboot_cb(EventLoop_t *eloop) noexcept
533 service_set->stop_all_services(ShutdownType::REBOOT);
536 /* handle SIGQUIT (if we are system init) */
537 static void sigquit_cb(EventLoop_t *eloop) noexcept
539 // This allows remounting the filesystem read-only if the dinit binary has been
540 // unlinked. In that case the kernel holds the binary open, so that it can't be
542 close_control_socket(eloop);
543 execl("/sbin/shutdown", "/sbin/shutdown", (char *) 0);
544 log(LogLevel::ERROR, "Error executing /sbin/shutdown: ", strerror(errno));
547 /* handle SIGTERM/SIGQUIT - stop all services (not used for system daemon) */
548 static void sigterm_cb(EventLoop_t *eloop) noexcept
550 service_set->stop_all_services();