chiark / gitweb /
main: when ignoring a signal set SA_RESTART
[elogind.git] / main.c
diff --git a/main.c b/main.c
index c2f1ef856d5703769688c457522ba2d2282f6dda..3e2bfe10ca94b5ed384a9e6ca205d848c5de8e08 100644 (file)
--- a/main.c
+++ b/main.c
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <getopt.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <fcntl.h>
 
 #include "manager.h"
 #include "log.h"
 #include "mount-setup.h"
+#include "hostname-setup.h"
+#include "load-fragment.h"
 
 static enum {
         ACTION_RUN,
-        ACTION_HELP
+        ACTION_HELP,
+        ACTION_TEST,
+        ACTION_DUMP_CONFIGURATION_ITEMS
 } action = ACTION_RUN;
 
 static char *default_unit = NULL;
 static ManagerRunningAs running_as = _MANAGER_RUNNING_AS_INVALID;
 
+static bool dump_core = true;
+static bool crash_shell = false;
+static int crash_chvt = -1;
+
+static bool confirm_spawn = false;
+
+_noreturn static void freeze(void) {
+        for (;;)
+                pause();
+}
+
+_noreturn static void crash(int sig) {
+
+        if (!dump_core)
+                log_error("Caught <%s>, not dumping core.", strsignal(sig));
+        else {
+                pid_t pid;
+
+                if ((pid = fork()) < 0)
+                        log_error("Caught <%s>, cannot fork for core dump: %s", strsignal(sig), strerror(errno));
+
+                else if (pid == 0) {
+                        struct sigaction sa;
+                        struct rlimit rl;
+
+                        /* Enable default signal handler for core dump */
+                        zero(sa);
+                        sa.sa_handler = SIG_DFL;
+                        assert_se(sigaction(sig, &sa, NULL) == 0);
+
+                        /* Don't limit the core dump size */
+                        zero(rl);
+                        rl.rlim_cur = RLIM_INFINITY;
+                        rl.rlim_max = RLIM_INFINITY;
+                        setrlimit(RLIMIT_CORE, &rl);
+
+                        /* Just to be sure... */
+                        assert_se(chdir("/") == 0);
+
+                        /* Raise the signal again */
+                        raise(sig);
+
+                        assert_not_reached("We shouldn't be here...");
+                        _exit(1);
+
+                } else {
+                        int status, r;
+
+                        /* Order things nicely. */
+                        if ((r = waitpid(pid, &status, 0)) < 0)
+                                log_error("Caught <%s>, waitpid() failed: %s", strsignal(sig), strerror(errno));
+                        else if (!WCOREDUMP(status))
+                                log_error("Caught <%s>, core dump failed.", strsignal(sig));
+                        else
+                                log_error("Caught <%s>, dumped core as pid %llu.", strsignal(sig), (unsigned long long) pid);
+                }
+        }
+
+        if (crash_chvt)
+                chvt(crash_chvt);
+
+        if (crash_shell) {
+                log_info("Executing crash shell in 10s...");
+                sleep(10);
+
+                execl("/bin/sh", "/bin/sh", NULL);
+                log_error("execl() failed: %s", strerror(errno));
+        }
+
+        log_info("Freezing execution.");
+        freeze();
+}
+
+static void install_crash_handler(void) {
+        struct sigaction sa;
+
+        zero(sa);
+
+        sa.sa_handler = crash;
+        sa.sa_flags = SA_NODEFER;
+
+        assert_se(sigaction(SIGSEGV, &sa, NULL) == 0);
+        assert_se(sigaction(SIGILL, &sa, NULL) == 0);
+        assert_se(sigaction(SIGFPE, &sa, NULL) == 0);
+        assert_se(sigaction(SIGBUS, &sa, NULL) == 0);
+        assert_se(sigaction(SIGQUIT, &sa, NULL) == 0);
+        assert_se(sigaction(SIGABRT, &sa, NULL) == 0);
+}
+
+static int console_setup(void) {
+        int tty_fd = -1, null_fd = -1, r = 0;
+
+        /* If we are init, we connect stdout/stderr to /dev/console
+         * and stdin to /dev/null and make sure we don't have a
+         * controlling tty. */
+
+        release_terminal();
+
+        if ((tty_fd = open_terminal("/dev/console", O_WRONLY)) < 0) {
+                log_error("Failed to open /dev/console: %s", strerror(-tty_fd));
+                r = -tty_fd;
+                goto finish;
+        }
+
+        if ((null_fd = open("/dev/null", O_RDONLY)) < 0) {
+                log_error("Failed to open /dev/null: %m");
+                r = -errno;
+                goto finish;
+        }
+
+        assert(tty_fd >= 3);
+        assert(null_fd >= 3);
+
+        if (reset_terminal(tty_fd) < 0)
+                log_error("Failed to reset /dev/console: %m");
+
+        if (dup2(tty_fd, STDOUT_FILENO) < 0 ||
+            dup2(tty_fd, STDERR_FILENO) < 0 ||
+            dup2(null_fd, STDIN_FILENO) < 0) {
+                log_error("Failed to dup2() device: %m");
+                r = -errno;
+                goto finish;
+        }
+
+        r = 0;
+
+finish:
+        if (tty_fd >= 0)
+                close_nointr(tty_fd);
+
+        if (null_fd >= 0)
+                close_nointr(null_fd);
+
+        return r;
+}
+
 static int set_default_unit(const char *u) {
         char *c;
 
@@ -69,7 +212,7 @@ static int parse_proc_cmdline_word(const char *word) {
         };
 
         if (startswith(word, "systemd.default="))
-                return set_default_unit(word + 15);
+                return set_default_unit(word + 16);
 
         else if (startswith(word, "systemd.log_target=")) {
 
@@ -81,11 +224,46 @@ static int parse_proc_cmdline_word(const char *word) {
                 if (log_set_max_level_from_string(word + 18) < 0)
                         log_warning("Failed to parse log level %s. Ignoring.", word + 18);
 
+        } else if (startswith(word, "systemd.dump_core=")) {
+                int r;
+
+                if ((r = parse_boolean(word + 18)) < 0)
+                        log_warning("Failed to parse dump core switch %s, Ignoring.", word + 18);
+                else
+                        dump_core = r;
+
+        } else if (startswith(word, "systemd.crash_shell=")) {
+                int r;
+
+                if ((r = parse_boolean(word + 20)) < 0)
+                        log_warning("Failed to parse crash shell switch %s, Ignoring.", word + 20);
+                else
+                        crash_shell = r;
+
+        } else if (startswith(word, "systemd.crash_chvt=")) {
+                int k;
+
+                if (safe_atoi(word + 19, &k) < 0)
+                        log_warning("Failed to parse crash chvt switch %s, Ignoring.", word + 19);
+                else
+                        crash_chvt = k;
+
+        } else if (startswith(word, "systemd.")) {
+
+                log_warning("Unknown kernel switch %s. Ignoring.", word);
+
+                log_info("Supported kernel switches:");
+                log_info("systemd.default=UNIT                     Default unit to start");
+                log_info("systemd.log_target=console|kmsg|syslog   Log target");
+                log_info("systemd.log_level=LEVEL                  Log level");
+                log_info("systemd.dump_core=0|1                    Dump core on crash");
+                log_info("systemd.crash_shell=0|1                  On crash run shell");
+                log_info("systemd.crash_chvt=N                     Change to VT #N on crash");
+
         } else {
                 unsigned i;
 
                 /* SysV compatibility */
-
                 for (i = 0; i < ELEMENTSOF(rlmap); i += 2)
                         if (streq(word, rlmap[i]))
                                 return set_default_unit(rlmap[i+1]);
@@ -134,7 +312,10 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_LOG_LEVEL = 0x100,
                 ARG_LOG_TARGET,
                 ARG_DEFAULT,
-                ARG_RUNNING_AS
+                ARG_RUNNING_AS,
+                ARG_TEST,
+                ARG_DUMP_CONFIGURATION_ITEMS,
+                ARG_CONFIRM_SPAWN
         };
 
         static const struct option options[] = {
@@ -142,7 +323,10 @@ static int parse_argv(int argc, char *argv[]) {
                 { "log-target", required_argument, NULL, ARG_LOG_TARGET },
                 { "default",    required_argument, NULL, ARG_DEFAULT },
                 { "running-as", required_argument, NULL, ARG_RUNNING_AS },
+                { "test",       no_argument,       NULL, ARG_TEST },
                 { "help",       no_argument,       NULL, 'h' },
+                { "dump-configuration-items", no_argument, NULL, ARG_DUMP_CONFIGURATION_ITEMS },
+                { "confirm-spawn", no_argument,    NULL, ARG_CONFIRM_SPAWN },
                 { NULL,         0,                 NULL, 0 }
         };
 
@@ -193,6 +377,18 @@ static int parse_argv(int argc, char *argv[]) {
                         break;
                 }
 
+                case ARG_TEST:
+                        action = ACTION_TEST;
+                        break;
+
+                case ARG_DUMP_CONFIGURATION_ITEMS:
+                        action = ACTION_DUMP_CONFIGURATION_ITEMS;
+                        break;
+
+                case ARG_CONFIRM_SPAWN:
+                        confirm_spawn = true;
+                        break;
+
                 case 'h':
                         action = ACTION_HELP;
                         break;
@@ -205,22 +401,20 @@ static int parse_argv(int argc, char *argv[]) {
                         return -EINVAL;
                 }
 
-        if (optind < argc) {
-                log_error("Too many arguments.");
-                return -EINVAL;
-        }
-
         return 0;
 }
 
 static int help(void) {
 
         printf("%s [options]\n\n"
-               "  -h --help               Show this help\n"
-               "     --default=UNIT       Set default unit\n"
-               "     --log-level=LEVEL    Set log level\n"
-               "     --log-target=TARGET  Set log target (console, syslog, kmsg)\n"
-               "     --running-as=AS      Set running as (init, system, sesstion)\n",
+               "  -h --help                      Show this help\n"
+               "     --default=UNIT              Set default unit\n"
+               "     --log-level=LEVEL           Set log level\n"
+               "     --log-target=TARGET         Set log target (console, syslog, kmsg)\n"
+               "     --running-as=AS             Set running as (init, system, session)\n"
+               "     --test                      Determine startup sequence, dump it and exit\n"
+               "     --dump-configuration-items  Dump understood unit configuration items\n"
+               "     --confirm-spawn             Ask for confirmation when spawning processes\n",
                __progname);
 
         return 0;
@@ -244,11 +438,16 @@ int main(int argc, char *argv[]) {
 
         /* Mount /proc, /sys and friends, so that /proc/cmdline and
          * /proc/$PID/fd is available. */
-        mount_setup();
+        if (mount_setup() < 0)
+                goto finish;
 
         /* Reset all signal handlers. */
         assert_se(reset_all_signal_handlers() == 0);
 
+        /* If we are init, we can block sigkill. Yay. */
+        ignore_signal(SIGKILL);
+        ignore_signal(SIGPIPE);
+
         /* Close all open files */
         assert_se(close_all_fds(NULL, 0) == 0);
 
@@ -264,29 +463,51 @@ int main(int argc, char *argv[]) {
         if (action == ACTION_HELP) {
                 retval = help();
                 goto finish;
+        } else if (action == ACTION_DUMP_CONFIGURATION_ITEMS) {
+                unit_dump_config_items(stdout);
+                retval = 0;
+                goto finish;
         }
 
-        assert_se(action == ACTION_RUN);
+        assert_se(action == ACTION_RUN || action == ACTION_TEST);
+
+        /* Set up PATH unless it is already set */
+        setenv("PATH",
+               "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
+               running_as == MANAGER_INIT);
 
         /* Move out of the way, so that we won't block unmounts */
         assert_se(chdir("/")  == 0);
 
-        /* Become a session leader if we aren't one yet. */
-        setsid();
+        if (running_as != MANAGER_SESSION) {
+                /* Become a session leader if we aren't one yet. */
+                setsid();
+
+                /* Disable the umask logic */
+                umask(0);
+        }
 
-        /* Disable the umask logic */
-        umask(0);
+        if (running_as == MANAGER_INIT)
+                console_setup();
 
         /* Make sure D-Bus doesn't fiddle with the SIGPIPE handlers */
         dbus_connection_set_change_sigpipe(FALSE);
 
-        /* Open the logging devices, if possible and necessary*/
+        /* Open the logging devices, if possible and necessary */
         log_open_syslog();
         log_open_kmsg();
 
+        /* Make sure we leave a core dump without panicing the
+         * kernel. */
+        if (getpid() == 1)
+                install_crash_handler();
+
         log_debug("systemd running in %s mode.", manager_running_as_to_string(running_as));
 
-        if ((r = manager_new(running_as, &m)) < 0) {
+        if (running_as == MANAGER_INIT)
+                hostname_setup();
+
+        if ((r = manager_new(running_as, confirm_spawn, &m)) < 0) {
                 log_error("Failed to allocate manager object: %s", strerror(-r));
                 goto finish;
         }
@@ -300,19 +521,34 @@ int main(int argc, char *argv[]) {
 
         if ((r = manager_load_unit(m, default_unit, &target)) < 0) {
                 log_error("Failed to load default target: %s", strerror(-r));
-                goto finish;
+
+                log_info("Trying to load rescue target...");
+                if ((r = manager_load_unit(m, SPECIAL_RESCUE_TARGET, &target)) < 0) {
+                        log_error("Failed to load rescue target: %s", strerror(-r));
+                        goto finish;
+                }
         }
 
-        printf("→ By units:\n");
-        manager_dump_units(m, stdout, "\t");
+        if (action == ACTION_TEST) {
+                printf("→ By units:\n");
+                manager_dump_units(m, stdout, "\t");
+        }
 
         if ((r = manager_add_job(m, JOB_START, target, JOB_REPLACE, false, &job)) < 0) {
                 log_error("Failed to start default target: %s", strerror(-r));
                 goto finish;
         }
 
-        printf("→ By jobs:\n");
-        manager_dump_jobs(m, stdout, "\t");
+        if (action == ACTION_TEST) {
+                printf("→ By jobs:\n");
+                manager_dump_jobs(m, stdout, "\t");
+
+                if (getpid() == 1)
+                        pause();
+
+                retval = 0;
+                goto finish;
+        }
 
         if ((r = manager_loop(m)) < 0) {
                 log_error("Failed to run mainloop: %s", strerror(-r));