service: introduce Type=idle and use it for gettys

Type=idle is much like Type=simple, however between the fork() and the
exec() in the child we wait until PID 1 informs us that no jobs are
left.

This is mostly a cosmetic fix to make gettys appear only after all boot
output is finished and complete.

Note that this does not impact the normal job logic as we do not delay
the completion of any jobs. We just delay the invocation of the actual
binary, and only for services that otherwise would be of Type=simple.

10 files changed, 45 insertions, 4 deletions

diff --git a/src/core/execute.c b/src/core/execute.c
index c59f7e2daa..99a7881f1c 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -37,6 +37,7 @@
 #include <sys/mount.h>
 #include <linux/fs.h>
 #include <linux/oom.h>
+#include <sys/poll.h>
 
 #ifdef HAVE_PAM
 #include <security/pam_appl.h>
@@ -963,6 +964,7 @@ int exec_spawn(ExecCommand *command,
                CGroupBonding *cgroup_bondings,
                CGroupAttribute *cgroup_attributes,
                const char *cgroup_suffix,
+               int idle_pipe[2],
                pid_t *ret) {
 
         pid_t pid;
@@ -1050,6 +1052,15 @@ int exec_spawn(ExecCommand *command,
                         goto fail_child;
                 }
 
+                if (idle_pipe) {
+                        if (idle_pipe[1] >= 0)
+                                close_nointr_nofail(idle_pipe[1]);
+                        if (idle_pipe[0] >= 0) {
+                                fd_wait_for_event(idle_pipe[0], POLLHUP, DEFAULT_TIMEOUT_USEC);
+                                close_nointr_nofail(idle_pipe[0]);
+                        }
+                }
+
                 /* Close sockets very early to make sure we don't
                  * block init reexecution because it cannot bind its
                  * sockets */
diff --git a/src/core/execute.h b/src/core/execute.h
index 428bb7c9bf..03c63d465a 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -193,6 +193,7 @@ int exec_spawn(ExecCommand *command,
                struct CGroupBonding *cgroup_bondings,
                struct CGroupAttribute *cgroup_attributes,
                const char *cgroup_suffix,
+               int pipe_fd[2],
                pid_t *ret);
 
 void exec_command_done(ExecCommand *c);
diff --git a/src/core/manager.c b/src/core/manager.c
index f7ccba6235..a6013668b8 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -259,6 +259,7 @@ int manager_new(ManagerRunningAs running_as, Manager **_m) {
         m->name_data_slot = m->conn_data_slot = m->subscribed_data_slot = -1;
         m->exit_code = _MANAGER_EXIT_CODE_INVALID;
         m->pin_cgroupfs_fd = -1;
+        m->idle_pipe[0] = m->idle_pipe[1] = -1;
 
 #ifdef HAVE_AUDIT
         m->audit_fd = -1;
@@ -518,6 +519,8 @@ void manager_free(Manager *m) {
         hashmap_free(m->cgroup_bondings);
         set_free_free(m->unit_path_cache);
 
+        close_pipe(m->idle_pipe);
+
         free(m);
 }
 
@@ -1962,10 +1965,13 @@ void manager_check_finished(Manager *m) {
 
         assert(m);
 
-        if (dual_timestamp_is_set(&m->finish_timestamp))
+        if (hashmap_size(m->jobs) > 0)
                 return;
 
-        if (hashmap_size(m->jobs) > 0)
+        /* Notify Type=idle units that we are done now */
+        close_pipe(m->idle_pipe);
+
+        if (dual_timestamp_is_set(&m->finish_timestamp))
                 return;
 
         dual_timestamp_get(&m->finish_timestamp);
diff --git a/src/core/manager.h b/src/core/manager.h
index 808a0d4286..154c1faeb7 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -227,6 +227,9 @@ struct Manager {
 
         unsigned n_installed_jobs;
         unsigned n_failed_jobs;
+
+        /* Type=idle pipes */
+        int idle_pipe[2];
 };
 
 int manager_new(ManagerRunningAs running_as, Manager **m);
diff --git a/src/core/mount.c b/src/core/mount.c
index e662af0c87..3357b7df5b 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -801,6 +801,7 @@ static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
                             UNIT(m)->cgroup_bondings,
                             UNIT(m)->cgroup_attributes,
                             NULL,
+                            NULL,
                             &pid)) < 0)
                 goto fail;
 
diff --git a/src/core/service.c b/src/core/service.c
index 59dd71294b..4358a948de 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1769,6 +1769,7 @@ static int service_spawn(
                        UNIT(s)->cgroup_bondings,
                        UNIT(s)->cgroup_attributes,
                        is_control ? "control" : NULL,
+                       s->type == SERVICE_IDLE ? UNIT(s)->manager->idle_pipe : NULL,
                        &pid);
 
         if (r < 0)
@@ -2130,7 +2131,7 @@ static void service_enter_start(Service *s) {
         if (r < 0)
                 goto fail;
 
-        if (s->type == SERVICE_SIMPLE) {
+        if (s->type == SERVICE_SIMPLE || s->type == SERVICE_IDLE) {
                 /* For simple services we immediately start
                  * the START_POST binaries. */
 
@@ -3714,7 +3715,8 @@ static const char* const service_type_table[_SERVICE_TYPE_MAX] = {
         [SERVICE_FORKING] = "forking",
         [SERVICE_ONESHOT] = "oneshot",
         [SERVICE_DBUS] = "dbus",
-        [SERVICE_NOTIFY] = "notify"
+        [SERVICE_NOTIFY] = "notify",
+        [SERVICE_IDLE] = "idle"
 };
 
 DEFINE_STRING_TABLE_LOOKUP(service_type, ServiceType);
diff --git a/src/core/service.h b/src/core/service.h
index eb41314931..819672f617 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -65,6 +65,7 @@ typedef enum ServiceType {
         SERVICE_ONESHOT,  /* we fork and wait until the program finishes (i.e. programs like fsck which run and need to finish before we continue) */
         SERVICE_DBUS,     /* we fork and wait until a specific D-Bus name appears on the bus */
         SERVICE_NOTIFY,   /* we fork and wait until a daemon sends us a ready message with sd_notify() */
+        SERVICE_IDLE,     /* much like simple, but delay exec() until all jobs are dispatched. */
         _SERVICE_TYPE_MAX,
         _SERVICE_TYPE_INVALID = -1
 } ServiceType;
diff --git a/src/core/socket.c b/src/core/socket.c
index 31aff5bcec..1d56829baf 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1152,6 +1152,7 @@ static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
                        UNIT(s)->cgroup_bondings,
                        UNIT(s)->cgroup_attributes,
                        NULL,
+                       NULL,
                        &pid);
 
         strv_free(argv);
diff --git a/src/core/swap.c b/src/core/swap.c
index 9c30c11bb4..fea3f6887a 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -620,6 +620,7 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
                             UNIT(s)->cgroup_bondings,
                             UNIT(s)->cgroup_attributes,
                             NULL,
+                            NULL,
                             &pid)) < 0)
                 goto fail;
 
diff --git a/src/core/transaction.c b/src/core/transaction.c
index aee155f519..09ed80737d 100644
--- a/src/core/transaction.c
+++ b/src/core/transaction.c
@@ -19,6 +19,9 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <unistd.h>
+#include <fcntl.h>
+
 #include "transaction.h"
 #include "bus-errors.h"
 
@@ -693,6 +696,17 @@ int transaction_activate(Transaction *tr, Manager *m, JobMode mode, DBusError *e
 
         assert(hashmap_isempty(tr->jobs));
 
+        if (!hashmap_isempty(m->jobs)) {
+                /* Are there any jobs now? Then make sure we have the
+                 * idle pipe around. We don't really care too much
+                 * whether this works or not, as the idle pipe is a
+                 * feature for cosmetics, not actually useful for
+                 * anything beyond that. */
+
+                if (m->idle_pipe[0] < 0 && m->idle_pipe[1] < 0)
+                        pipe2(m->idle_pipe, O_NONBLOCK|O_CLOEXEC);
+        }
+
         return 0;
 }