chiark / gitweb /
manager: start D-Bus on SIGUSR2
[elogind.git] / manager.c
index cf13e254d51822c3d5538b802c0e9f6a4cf87f80..82dc9a676bb344273aeb2b9c9f9adc0cbf715bf5 100644 (file)
--- a/manager.c
+++ b/manager.c
@@ -33,6 +33,8 @@
 #include <sys/ioctl.h>
 #include <linux/kd.h>
 #include <libcgroup.h>
+#include <termios.h>
+#include <fcntl.h>
 
 #include "manager.h"
 #include "hashmap.h"
 #include "mount-setup.h"
 #include "utmp-wtmp.h"
 
+static int enable_special_signals(Manager *m) {
+        char fd;
+
+        assert(m);
+
+        /* Enable that we get SIGINT on control-alt-del */
+        if (reboot(RB_DISABLE_CAD) < 0)
+                log_warning("Failed to enable ctrl-alt-del handling: %m");
+
+        if ((fd = open_terminal("/dev/tty0", O_RDWR)) < 0)
+                log_warning("Failed to open /dev/tty0: %m");
+        else {
+                /* Enable that we get SIGWINCH on kbrequest */
+                if (ioctl(fd, KDSIGACCEPT, SIGWINCH) < 0)
+                        log_warning("Failed to enable kbrequest handling: %s", strerror(errno));
+
+                close_nointr_nofail(fd);
+        }
+
+        return 0;
+}
+
 static int manager_setup_signals(Manager *m) {
         sigset_t mask;
         struct epoll_event ev;
+        struct sigaction sa;
 
         assert(m);
 
+        /* We are not interested in SIGSTOP and friends. */
+        zero(sa);
+        sa.sa_handler = SIG_DFL;
+        sa.sa_flags = SA_NOCLDSTOP|SA_RESTART;
+        assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
+
         assert_se(sigemptyset(&mask) == 0);
         assert_se(sigaddset(&mask, SIGCHLD) == 0);
-        assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
-        assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
         assert_se(sigaddset(&mask, SIGTERM) == 0);
         assert_se(sigaddset(&mask, SIGHUP) == 0);
         assert_se(sigaddset(&mask, SIGUSR1) == 0);
         assert_se(sigaddset(&mask, SIGUSR2) == 0);
-        assert_se(sigaddset(&mask, SIGPWR) == 0);
+        assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
+        assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
+        assert_se(sigaddset(&mask, SIGPWR) == 0);   /* Some kernel drivers and upsd send us this on power failure */
         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
 
         m->signal_watch.type = WATCH_SIGNAL;
@@ -73,15 +104,8 @@ static int manager_setup_signals(Manager *m) {
         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
                 return -errno;
 
-        if (m->running_as == MANAGER_INIT) {
-                /* Enable that we get SIGINT on control-alt-del */
-                if (reboot(RB_DISABLE_CAD) < 0)
-                        log_warning("Failed to enable ctrl-alt-del handling: %s", strerror(errno));
-
-                /* Enable that we get SIGWINCH on kbrequest */
-                if (ioctl(0, KDSIGACCEPT, SIGWINCH) < 0)
-                        log_warning("Failed to enable kbrequest handling: %s", strerror(errno));
-        }
+        if (m->running_as == MANAGER_INIT)
+                return enable_special_signals(m);
 
         return 0;
 }
@@ -280,7 +304,7 @@ static int manager_find_paths(Manager *m) {
         return 0;
 }
 
-int manager_new(ManagerRunningAs running_as, Manager **_m) {
+int manager_new(ManagerRunningAs running_as, bool confirm_spawn, Manager **_m) {
         Manager *m;
         int r = -ENOMEM;
 
@@ -294,6 +318,8 @@ int manager_new(ManagerRunningAs running_as, Manager **_m) {
         m->boot_timestamp = now(CLOCK_REALTIME);
 
         m->running_as = running_as;
+        m->confirm_spawn = confirm_spawn;
+
         m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = -1;
         m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
 
@@ -1440,26 +1466,53 @@ static int manager_dispatch_sigchld(Manager *m) {
                 Unit *u;
 
                 zero(si);
-                if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG) < 0) {
+
+                /* First we call waitd() for a PID and do not reap the
+                 * zombie. That way we can still access /proc/$PID for
+                 * it while it is a zombie. */
+                if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG|WNOWAIT) < 0) {
 
                         if (errno == ECHILD)
                                 break;
 
+                        if (errno == EINTR)
+                                continue;
+
                         return -errno;
                 }
 
-                if (si.si_pid == 0)
+                if (si.si_pid <= 0)
                         break;
 
+                if (si.si_code == CLD_EXITED || si.si_code == CLD_KILLED || si.si_code == CLD_DUMPED) {
+                        char *name = NULL;
+
+                        get_process_name(si.si_pid, &name);
+                        log_debug("Got SIGCHLD for process %llu (%s)", (unsigned long long) si.si_pid, strna(name));
+                        free(name);
+                }
+
+                /* And now, we actually reap the zombie. */
+                if (waitid(P_PID, si.si_pid, &si, WEXITED) < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        return -errno;
+                }
+
                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
                         continue;
 
-                log_debug("child %llu died (code=%s, status=%i)", (long long unsigned) si.si_pid, sigchld_code_to_string(si.si_code), si.si_status);
+                log_debug("Child %llu died (code=%s, status=%i/%s)",
+                          (long long unsigned) si.si_pid,
+                          sigchld_code_to_string(si.si_code),
+                          si.si_status,
+                          strna(si.si_code == CLD_EXITED ? exit_status_to_string(si.si_status) : strsignal(si.si_status)));
 
                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
                         continue;
 
-                log_debug("child %llu belongs to %s", (long long unsigned) si.si_pid, unit_id(u));
+                log_debug("Child %llu belongs to %s", (long long unsigned) si.si_pid, unit_id(u));
 
                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
         }
@@ -1495,16 +1548,9 @@ static int manager_process_signal_fd(Manager *m, bool *quit) {
 
                 switch (sfsi.ssi_signo) {
 
-                case SIGCHLD: {
-                        char *name = NULL;
-
-                        get_process_name(sfsi.ssi_pid, &name);
-                        log_debug("Got SIGCHLD for process %llu (%s)", (unsigned long long) sfsi.ssi_pid, strna(name));
-                        free(name);
-
+                case SIGCHLD:
                         sigchld = true;
                         break;
-                }
 
                 case SIGINT:
                 case SIGTERM:
@@ -1533,14 +1579,28 @@ static int manager_process_signal_fd(Manager *m, bool *quit) {
                         break;
 
                 case SIGUSR1:
-
-                        printf("→ By units:\n");
                         manager_dump_units(m, stdout, "\t");
-
-                        printf("→ By jobs:\n");
                         manager_dump_jobs(m, stdout, "\t");
+                        break;
+
+                case SIGUSR2:  {
+                        Unit *u;
+
+                        u = manager_get_unit(m, SPECIAL_DBUS_SERVICE);
+
+                        if (!u || UNIT_IS_ACTIVE_OR_RELOADING(unit_active_state(u))) {
+                                log_info("Trying to reconnect to bus...");
+                                bus_init_system(m);
+                                bus_init_api(m);
+                        }
+
+                        if (!u || !UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(u))) {
+                                log_info("Loading D-Bus service...");
+                                manager_start_target(m, SPECIAL_DBUS_SERVICE);
+                        }
 
                         break;
+                }
 
                 default:
                         log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));