core: add support for setting stdin/stdout/stderr for transient services

When starting a transient service, allow setting stdin/stdout/stderr fds
for it, by passing them in via the bus.

This also simplifies some of the serialization code for units.

1 files changed, 4 insertions, 9 deletions

diff --git a/src/core/busname.c b/src/core/busname.c
index ba353ab660..38becfc119 100644
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -656,6 +656,7 @@ static int busname_stop(Unit *u) {
 
 static int busname_serialize(Unit *u, FILE *f, FDSet *fds) {
         BusName *n = BUSNAME(u);
+        int r;
 
         assert(n);
         assert(f);
@@ -667,15 +668,9 @@ static int busname_serialize(Unit *u, FILE *f, FDSet *fds) {
         if (n->control_pid > 0)
                 unit_serialize_item_format(u, f, "control-pid", PID_FMT, n->control_pid);
 
-        if (n->starter_fd >= 0) {
-                int copy;
-
-                copy = fdset_put_dup(fds, n->starter_fd);
-                if (copy < 0)
-                        return copy;
-
-                unit_serialize_item_format(u, f, "starter-fd", "%i", copy);
-        }
+        r = unit_serialize_item_fd(u, f, fds, "starter-fd", n->starter_fd);
+        if (r < 0)
+                return r;
 
         return 0;
 }