logind: add a new UserTasksMax= setting to logind.conf

This new setting configures the TasksMax= field for the slice objects we
create for each user.

This alters logind to create the slice unit as transient unit explicitly
instead of relying on implicit generation of slice units by simply
starting them. This also enables us to set a friendly description for
slice units that way.

1 files changed, 93 insertions, 1 deletions

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 7890d68aa0..1b460b3bb0 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -2740,13 +2740,101 @@ int manager_send_changed(Manager *manager, const char *property, ...) {
                         l);
 }
 
+int manager_start_slice(
+                Manager *manager,
+                const char *slice,
+                const char *description,
+                const char *after,
+                const char *after2,
+                uint64_t tasks_max,
+                sd_bus_error *error,
+                char **job) {
+
+        _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        int r;
+
+        assert(manager);
+        assert(slice);
+
+        r = sd_bus_message_new_method_call(
+                        manager->bus,
+                        &m,
+                        "org.freedesktop.systemd1",
+                        "/org/freedesktop/systemd1",
+                        "org.freedesktop.systemd1.Manager",
+                        "StartTransientUnit");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "ss", strempty(slice), "fail");
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_open_container(m, 'a', "(sv)");
+        if (r < 0)
+                return r;
+
+        if (!isempty(description)) {
+                r = sd_bus_message_append(m, "(sv)", "Description", "s", description);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!isempty(after)) {
+                r = sd_bus_message_append(m, "(sv)", "After", "as", 1, after);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!isempty(after2)) {
+                r = sd_bus_message_append(m, "(sv)", "After", "as", 1, after2);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", tasks_max);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_close_container(m);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(m, "a(sa(sv))", 0);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_call(manager->bus, m, 0, error, &reply);
+        if (r < 0)
+                return r;
+
+        if (job) {
+                const char *j;
+                char *copy;
+
+                r = sd_bus_message_read(reply, "o", &j);
+                if (r < 0)
+                        return r;
+
+                copy = strdup(j);
+                if (!copy)
+                        return -ENOMEM;
+
+                *job = copy;
+        }
+
+        return 1;
+}
+
 int manager_start_scope(
                 Manager *manager,
                 const char *scope,
                 pid_t pid,
                 const char *slice,
                 const char *description,
-                const char *after, const char *after2,
+                const char *after,
+                const char *after2,
+                uint64_t tasks_max,
                 sd_bus_error *error,
                 char **job) {
 
@@ -2814,6 +2902,10 @@ int manager_start_scope(
         if (r < 0)
                 return r;
 
+        r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", tasks_max);
+        if (r < 0)
+                return r;
+
         r = sd_bus_message_close_container(m);
         if (r < 0)
                 return r;