12 #include <sys/socket.h>
17 #include <sys/prctl.h>
19 #include <sys/reboot.h>
21 #if defined(__FreeBSD__) || defined(__DragonFly__)
22 #include <sys/procctl.h>
29 #include "dinit-log.h"
30 #include "dinit-socket.h"
31 #include "static-string.h"
36 * When running as the system init process, Dinit processes the following signals:
38 * SIGTERM - roll back services and then fork/exec /sbin/halt
39 * SIGINT - roll back services and then fork/exec /sbin/reboot
40 * SIGQUIT - exec() /sbin/shutdown without rolling back services
42 * It's an open question about whether Dinit should roll back services *before*
43 * running halt/reboot, since those commands should prompt rollback of services
44 * anyway. But it seems safe to do so, and it means the user can at least stop
45 * services even if the halt/reboot commands are unavailable for some reason.
50 using eventloop_t = dasynq::event_loop<dasynq::null_mutex>;
52 eventloop_t event_loop;
54 static void sigint_reboot_cb(eventloop_t &eloop) noexcept;
55 static void sigquit_cb(eventloop_t &eloop) noexcept;
56 static void sigterm_cb(eventloop_t &eloop) noexcept;
57 static void close_control_socket() noexcept;
58 static void wait_for_user_input() noexcept;
59 static void read_env_file(const char *);
61 static void control_socket_cb(eventloop_t *loop, int fd);
66 static dirload_service_set *services;
68 static bool am_system_init = false; // true if we are the system init process
70 static bool control_socket_open = false;
71 static bool external_log_open = false;
72 int active_control_conns = 0;
74 // Control socket path. We maintain a string (control_socket_str) in case we need
75 // to allocate storage, but control_socket_path is the authoritative value.
76 static const char *control_socket_path = SYSCONTROLSOCKET;
77 static std::string control_socket_str;
79 static const char *env_file_path = "/etc/dinit/environment";
81 static const char *log_path = "/dev/log";
82 static bool log_is_syslog = true; // if false, log is a file
84 static const char *user_home_path = nullptr;
87 // Get user home (and set user_home_path). (The return may become invalid after
88 // changing the evironment (HOME variable) or using the getpwuid() function).
89 const char * get_user_home()
91 if (user_home_path == nullptr) {
92 user_home_path = getenv("HOME");
93 if (user_home_path == nullptr) {
94 struct passwd * pwuid_p = getpwuid(getuid());
95 if (pwuid_p != nullptr) {
96 user_home_path = pwuid_p->pw_dir;
100 return user_home_path;
105 class callback_signal_handler : public eventloop_t::signal_watcher_impl<callback_signal_handler>
107 using rearm = dasynq::rearm;
110 typedef void (*cb_func_t)(eventloop_t &);
116 callback_signal_handler() : cb_func(nullptr) { }
117 callback_signal_handler(cb_func_t pcb_func) : cb_func(pcb_func) { }
119 void setCbFunc(cb_func_t cb_func)
121 this->cb_func = cb_func;
124 rearm received(eventloop_t &eloop, int signo, siginfo_p siginfo)
131 class control_socket_watcher : public eventloop_t::fd_watcher_impl<control_socket_watcher>
133 using rearm = dasynq::rearm;
136 rearm fd_event(eventloop_t &loop, int fd, int flags) noexcept
138 control_socket_cb(&loop, fd);
143 // Simple timer used to limit the amount of time waiting for the log flush to complete (at shutdown)
144 class log_flush_timer_t : public eventloop_t::timer_impl<log_flush_timer_t>
146 using rearm = dasynq::rearm;
148 bool expired = false;
151 rearm timer_expiry(eventloop_t &, int expiry_count)
154 return rearm::DISARM;
163 control_socket_watcher control_socket_io;
164 log_flush_timer_t log_flush_timer;
167 int dinit_main(int argc, char **argv)
171 am_system_init = (getpid() == 1);
172 const char * service_dir = nullptr;
173 bool service_dir_dynamic = false; // service_dir dynamically allocated?
174 const char * env_file = nullptr;
175 string service_dir_str; // to hold storage for above if necessary
176 bool control_socket_path_set = false;
177 bool env_file_set = false;
179 // list of services to start
180 list<const char *> services_to_start;
182 // Arguments, if given, specify a list of services to start.
183 // If we are running as init (PID=1), the Linux kernel gives us any command line arguments it was given
184 // but didn't recognize, including "single" (usually for "boot to single user mode" aka just start the
185 // shell). We can treat them as service names. In the worst case we can't find any of the named
186 // services, and so we'll start the "boot" service by default.
188 for (int i = 1; i < argc; i++) {
189 if (argv[i][0] == '-') {
191 if (strcmp(argv[i], "--env-file") == 0 || strcmp(argv[i], "-e") == 0) {
197 cerr << "dinit: '--env-file' (-e) requires an argument" << endl;
200 else if (strcmp(argv[i], "--services-dir") == 0 || strcmp(argv[i], "-d") == 0) {
202 service_dir = argv[i];
205 cerr << "dinit: '--services-dir' (-d) requires an argument" << endl;
209 else if (strcmp(argv[i], "--system") == 0 || strcmp(argv[i], "-s") == 0) {
210 am_system_init = true;
212 else if (strcmp(argv[i], "--socket-path") == 0 || strcmp(argv[i], "-p") == 0) {
214 control_socket_path = argv[i];
215 control_socket_path_set = true;
218 cerr << "dinit: '--socket-path' (-p) requires an argument" << endl;
222 else if (strcmp(argv[i], "--log-file") == 0 || strcmp(argv[i], "-l") == 0) {
225 log_is_syslog = false;
228 cerr << "dinit: '--log-file' (-l) requires an argument" << endl;
232 else if (strcmp(argv[i], "--help") == 0) {
233 cout << "dinit, an init with dependency management" << endl;
234 cout << " --help display help" << endl;
235 cout << " --env-file <file>, -e <file>" << endl;
236 cout << " environment variable initialisation file" << endl;
237 cout << " --services-dir <dir>, -d <dir>" << endl;
238 cout << " set base directory for service description" << endl;
239 cout << " files (-d <dir>)" << endl;
240 cout << " --system, -s run as the system init process" << endl;
241 cout << " --socket-path <path>, -p <path>" << endl;
242 cout << " path to control socket" << endl;
243 cout << " <service-name> start service with name <service-name>" << endl;
248 if (! am_system_init) {
249 cerr << "dinit: Unrecognized option: " << argv[i] << endl;
256 // LILO puts "auto" on the kernel command line for unattended boots; we'll filter it.
257 if (! am_system_init || strcmp(argv[i], "auto") != 0) {
258 services_to_start.push_back(argv[i]);
261 services_to_start.push_back(argv[i]);
267 if (am_system_init) {
268 // setup STDIN, STDOUT, STDERR so that we can use them
269 int onefd = open("/dev/console", O_RDONLY, 0);
271 int twofd = open("/dev/console", O_RDWR, 0);
275 if (onefd > 2) close(onefd);
276 if (twofd > 2) close(twofd);
278 if (! env_file_set) {
279 env_file = env_file_path;
283 /* Set up signal handlers etc */
284 /* SIG_CHILD is ignored by default: good */
285 sigset_t sigwait_set;
286 sigemptyset(&sigwait_set);
287 sigaddset(&sigwait_set, SIGCHLD);
288 sigaddset(&sigwait_set, SIGINT);
289 sigaddset(&sigwait_set, SIGTERM);
290 if (am_system_init) sigaddset(&sigwait_set, SIGQUIT);
291 sigprocmask(SIG_BLOCK, &sigwait_set, NULL);
293 // Terminal access control signals - we block these so that dinit can't be
294 // suspended if it writes to the terminal after some other process has claimed
296 signal(SIGTSTP, SIG_IGN);
297 signal(SIGTTIN, SIG_IGN);
298 signal(SIGTTOU, SIG_IGN);
300 signal(SIGPIPE, SIG_IGN);
302 if (! am_system_init && ! control_socket_path_set) {
303 const char * userhome = get_user_home();
304 if (userhome != nullptr) {
305 control_socket_str = userhome;
306 control_socket_str += "/.dinitctl";
307 control_socket_path = control_socket_str.c_str();
311 /* service directory name */
312 if (service_dir == nullptr && ! am_system_init) {
313 const char * userhome = get_user_home();
314 if (userhome != nullptr) {
315 const char * user_home = get_user_home();
316 size_t user_home_len = strlen(user_home);
317 size_t dinit_d_len = strlen("/dinit.d");
318 size_t full_len = user_home_len + dinit_d_len + 1;
319 char *service_dir_w = new char[full_len];
320 std::memcpy(service_dir_w, user_home, user_home_len);
321 std::memcpy(service_dir_w + user_home_len, "/dinit.d", dinit_d_len);
322 service_dir_w[full_len - 1] = 0;
324 service_dir = service_dir_w;
325 service_dir_dynamic = true;
329 if (services_to_start.empty()) {
330 services_to_start.push_back("boot");
333 // Set up signal handlers
334 callback_signal_handler sigterm_watcher {sigterm_cb};
335 callback_signal_handler sigint_watcher;
336 callback_signal_handler sigquit_watcher;
338 if (am_system_init) {
339 sigint_watcher.setCbFunc(sigint_reboot_cb);
340 sigquit_watcher.setCbFunc(sigquit_cb);
343 sigint_watcher.setCbFunc(sigterm_cb);
346 sigint_watcher.add_watch(event_loop, SIGINT);
347 sigterm_watcher.add_watch(event_loop, SIGTERM);
349 if (am_system_init) {
350 // PID 1: SIGQUIT exec's shutdown
351 sigquit_watcher.add_watch(event_loop, SIGQUIT);
352 // As a user process, we instead just let SIGQUIT perform the default action.
355 // Try to open control socket (may fail due to readonly filesystem)
356 open_control_socket(false);
359 if (am_system_init) {
360 // Disable non-critical kernel output to console
361 klogctl(6 /* SYSLOG_ACTION_CONSOLE_OFF */, nullptr, 0);
362 // Make ctrl+alt+del combination send SIGINT to PID 1 (this process)
363 reboot(RB_DISABLE_CAD);
366 // Mark ourselves as a subreaper. This means that if a process we start double-forks, the
367 // orphaned child will re-parent to us rather than to PID 1 (although that could be us too).
368 prctl(PR_SET_CHILD_SUBREAPER, 1);
369 #elif defined(__FreeBSD__) || defined(__DragonFly__)
370 // Documentation (man page) for this kind of sucks. PROC_REAP_ACQUIRE "acquires the reaper status for
371 // the current process" but does that mean the first two arguments still need valid values to be
372 // supplied? We'll play it safe and explicitly target our own process:
373 procctl(P_PID, getpid(), PROC_REAP_ACQUIRE, NULL);
376 log_flush_timer.add_timer(event_loop, dasynq::clock_type::MONOTONIC);
378 bool add_all_service_dirs = false;
379 if (service_dir == nullptr) {
380 service_dir = "/etc/dinit.d";
381 add_all_service_dirs = true;
384 /* start requested services */
385 services = new dirload_service_set(service_dir, service_dir_dynamic);
386 if (add_all_service_dirs) {
387 services->add_service_dir("/usr/local/lib/dinit.d", false);
388 services->add_service_dir("/lib/dinit.d", false);
391 init_log(services, log_is_syslog);
392 if (am_system_init) {
393 log(loglevel_t::INFO, false, "starting system");
396 // Only try to set up the external log now if we aren't the system init. (If we are the
397 // system init, wait until the log service starts).
398 if (! am_system_init) setup_external_log();
400 if (env_file != nullptr) {
401 read_env_file(env_file);
404 for (auto svc : services_to_start) {
406 services->start_service(svc);
407 // Note in general if we fail to start a service we don't need any special error handling,
408 // since we either leave other services running or, if it was the only service, then no
409 // services will be running and we will process normally (reboot if system process,
410 // exit if user process).
412 catch (service_not_found &snf) {
413 log(loglevel_t::ERROR, snf.serviceName, ": Could not find service description.");
415 catch (service_load_exc &sle) {
416 log(loglevel_t::ERROR, sle.serviceName, ": ", sle.excDescription);
418 catch (std::bad_alloc &badalloce) {
419 log(loglevel_t::ERROR, "Out of memory when trying to start service: ", svc, ".");
426 // Process events until all services have terminated.
427 while (services->count_active_services() != 0) {
431 shutdown_type_t shutdown_type = services->get_shutdown_type();
433 if (am_system_init) {
434 log_msg_begin(loglevel_t::INFO, "No more active services.");
436 if (shutdown_type == shutdown_type_t::REBOOT) {
437 log_msg_end(" Will reboot.");
439 else if (shutdown_type == shutdown_type_t::HALT) {
440 log_msg_end(" Will halt.");
442 else if (shutdown_type == shutdown_type_t::POWEROFF) {
443 log_msg_end(" Will power down.");
446 log_msg_end(" Re-initiating boot sequence.");
450 log_flush_timer.arm_timer_rel(event_loop, timespec{5,0}); // 5 seconds
451 while (! is_log_flushed() && ! log_flush_timer.has_expired()) {
455 close_control_socket();
457 if (am_system_init) {
458 if (shutdown_type == shutdown_type_t::CONTINUE) {
459 // It could be that we started in single user mode, and the
460 // user has now exited the shell. We'll try and re-start the
463 services->start_service("boot");
464 goto event_loop; // yes, the "evil" goto
467 // Now what do we do? try to reboot, but wait for user ack to avoid boot loop.
468 log(loglevel_t::ERROR, "Could not start 'boot' service. Will attempt reboot.");
469 wait_for_user_input();
470 shutdown_type = shutdown_type_t::REBOOT;
474 const char * cmd_arg;
475 if (shutdown_type == shutdown_type_t::HALT) {
478 else if (shutdown_type == shutdown_type_t::REBOOT) {
486 // Fork and execute dinit-reboot.
487 constexpr auto shutdown_exec = literal(SBINDIR) + "/shutdown";
488 execl(shutdown_exec.c_str(), shutdown_exec.c_str(), "--system", cmd_arg, nullptr);
489 log(loglevel_t::ERROR, (literal("Could not execute ") + SBINDIR + "/shutdown: ").c_str(),
492 // PID 1 must not actually exit, although we should never reach this point:
497 else if (shutdown_type == shutdown_type_t::REBOOT) {
498 // Non-system-process. If we got SIGINT, let's die due to it:
499 sigset_t sigwait_set;
500 sigemptyset(&sigwait_set);
501 sigaddset(&sigwait_set, SIGINT);
503 sigprocmask(SIG_UNBLOCK, &sigwait_set, NULL);
509 static void log_bad_env(int linenum)
511 log(loglevel_t::ERROR, "invalid environment variable setting in environment file (line ", linenum, ")");
514 // Read and set environment variables from a file.
515 static void read_env_file(const char *env_file_path)
517 // Note that we can't use the log in this function; it hasn't been initialised yet.
519 std::ifstream env_file(env_file_path);
520 if (! env_file) return;
522 env_file.exceptions(std::ios::badbit);
524 auto &clocale = std::locale::classic();
528 while (std::getline(env_file, line)) {
530 auto lpos = line.begin();
531 auto lend = line.end();
532 while (lpos != lend && std::isspace(*lpos, clocale)) {
539 log_bad_env(linenum);
542 auto name_begin = lpos++;
543 // skip until '=' or whitespace:
544 while (lpos != lend && *lpos != '=' && ! std::isspace(*lpos, clocale)) ++lpos;
545 auto name_end = lpos;
547 while (lpos != lend && std::isspace(*lpos, clocale)) ++lpos;
549 log_bad_env(linenum);
554 auto val_begin = lpos;
555 while (lpos != lend && *lpos != '\n') ++lpos;
558 std::string name = line.substr(name_begin - line.begin(), name_end - name_begin);
559 std::string value = line.substr(val_begin - line.begin(), val_end - val_begin);
560 if (setenv(name.c_str(), value.c_str(), true) == -1) {
561 throw std::system_error(errno, std::system_category());
568 // In exception situations we want user confirmation before proceeding (eg on critical boot failure
569 // we wait before rebooting to avoid a reboot loop).
570 static void wait_for_user_input() noexcept
572 std::cout << "Press Enter to continue." << std::endl;
574 read(STDIN_FILENO, buf, 1);
577 // Callback for control socket
578 static void control_socket_cb(eventloop_t *loop, int sockfd)
580 // Considered keeping a limit the number of active connections, however, there doesn't
581 // seem much to be gained from that. Only root can create connections and not being
582 // able to establish a control connection is as much a denial-of-service as is not being
583 // able to start a service due to lack of fd's.
585 // Accept a connection
586 int newfd = dinit_accept4(sockfd, nullptr, nullptr, SOCK_NONBLOCK | SOCK_CLOEXEC);
590 new control_conn_t(*loop, services, newfd); // will delete itself when it's finished
592 catch (std::exception &exc) {
593 log(loglevel_t::ERROR, "Accepting control connection: ", exc.what());
599 void open_control_socket(bool report_ro_failure) noexcept
601 if (! control_socket_open) {
602 const char * saddrname = control_socket_path;
603 size_t saddrname_len = strlen(saddrname);
604 uint sockaddr_size = offsetof(struct sockaddr_un, sun_path) + saddrname_len + 1;
606 struct sockaddr_un * name = static_cast<sockaddr_un *>(malloc(sockaddr_size));
607 if (name == nullptr) {
608 log(loglevel_t::ERROR, "Opening control socket: out of memory");
612 if (am_system_init) {
613 // Unlink any stale control socket file, but only if we are system init, since otherwise
614 // the 'stale' file may not be stale at all:
618 name->sun_family = AF_UNIX;
619 memcpy(name->sun_path, saddrname, saddrname_len + 1);
621 int sockfd = dinit_socket(AF_UNIX, SOCK_STREAM, 0, SOCK_NONBLOCK | SOCK_CLOEXEC);
623 log(loglevel_t::ERROR, "Error creating control socket: ", strerror(errno));
628 if (bind(sockfd, (struct sockaddr *) name, sockaddr_size) == -1) {
629 if (errno != EROFS || report_ro_failure) {
630 log(loglevel_t::ERROR, "Error binding control socket: ", strerror(errno));
639 // No connections can be made until we listen, so it is fine to change the permissions now
640 // (and anyway there is no way to atomically create the socket and set permissions):
641 if (chmod(saddrname, S_IRUSR | S_IWUSR) == -1) {
642 log(loglevel_t::ERROR, "Error setting control socket permissions: ", strerror(errno));
647 if (listen(sockfd, 10) == -1) {
648 log(loglevel_t::ERROR, "Error listening on control socket: ", strerror(errno));
654 control_socket_io.add_watch(event_loop, sockfd, dasynq::IN_EVENTS);
655 control_socket_open = true;
657 catch (std::exception &e)
659 log(loglevel_t::ERROR, "Could not setup I/O on control socket: ", e.what());
665 static void close_control_socket() noexcept
667 if (control_socket_open) {
668 int fd = control_socket_io.get_watched_fd();
669 control_socket_io.deregister(event_loop);
672 // Unlink the socket:
673 unlink(control_socket_path);
677 void setup_external_log() noexcept
679 if (! external_log_open) {
681 const char * saddrname = log_path;
682 size_t saddrname_len = strlen(saddrname);
683 uint sockaddr_size = offsetof(struct sockaddr_un, sun_path) + saddrname_len + 1;
685 struct sockaddr_un * name = static_cast<sockaddr_un *>(malloc(sockaddr_size));
686 if (name == nullptr) {
687 log(loglevel_t::ERROR, "Connecting to log socket: out of memory");
691 name->sun_family = AF_UNIX;
692 memcpy(name->sun_path, saddrname, saddrname_len + 1);
694 int sockfd = dinit_socket(AF_UNIX, SOCK_DGRAM, 0, SOCK_NONBLOCK | SOCK_CLOEXEC);
696 log(loglevel_t::ERROR, "Error creating log socket: ", strerror(errno));
701 if (connect(sockfd, (struct sockaddr *) name, sockaddr_size) == 0 || errno == EINPROGRESS) {
702 // For EINPROGRESS, connection is still being established; however, we can select on
703 // the file descriptor so we will be notified when it's ready. In other words we can
704 // basically use it anyway.
706 setup_main_log(sockfd);
708 catch (std::exception &e) {
709 log(loglevel_t::ERROR, "Setting up log failed: ", e.what());
714 // Note if connect fails, we haven't warned at all, because the syslog server might not
723 int log_fd = open(log_path, O_WRONLY | O_CREAT | O_APPEND | O_NONBLOCK | O_CLOEXEC, 0644);
726 setup_main_log(log_fd);
728 catch (std::exception &e) {
729 log(loglevel_t::ERROR, "Setting up log failed: ", e.what());
734 // log failure to log? It makes more sense than first appears, because we also log to console:
735 log(loglevel_t::ERROR, "Setting up log failed: ", strerror(errno));
741 /* handle SIGINT signal (generated by Linux kernel when ctrl+alt+del pressed) */
742 static void sigint_reboot_cb(eventloop_t &eloop) noexcept
744 services->stop_all_services(shutdown_type_t::REBOOT);
747 /* handle SIGQUIT (if we are system init) */
748 static void sigquit_cb(eventloop_t &eloop) noexcept
750 // This performs an immediate shutdown, without service rollback.
751 close_control_socket();
752 constexpr auto shutdown_exec = literal(SBINDIR) + "/shutdown";
753 execl(shutdown_exec.c_str(), shutdown_exec.c_str(), "--system", (char *) 0);
754 log(loglevel_t::ERROR, literal("Error executing ") + SBINDIR + "/sbin/shutdown: ", strerror(errno));
755 sync(); // since a hard poweroff might be required at this point...
758 /* handle SIGTERM/SIGQUIT(non-system-daemon) - stop all services and shut down */
759 static void sigterm_cb(eventloop_t &eloop) noexcept
761 services->stop_all_services();