unit: rework trigger dependency logic

Instead of having explicit type-specific callbacks that inform the
triggering unit when a triggered unit changes state, make this generic
so that state changes are forwarded betwee any triggered and triggering
unit.

Also, get rid of UnitRef references from automount, timer, path units,
to the units they trigger and rely exclsuively on UNIT_TRIGGER type
dendencies.

1 files changed, 31 insertions, 72 deletions

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index c3f4f92611..0571d517b0 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -1254,50 +1254,57 @@ int config_parse_timer(const char *unit,
         return 0;
 }
 
-int config_parse_timer_unit(const char *unit,
-                            const char *filename,
-                            unsigned line,
-                            const char *section,
-                            const char *lvalue,
-                            int ltype,
-                            const char *rvalue,
-                            void *data,
-                            void *userdata) {
+int config_parse_trigger_unit(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
 
-        Timer *t = data;
-        int r;
-        DBusError error;
-        Unit *u;
         _cleanup_free_ char *p = NULL;
+        Unit *u = data;
+        UnitType type;
+        int r;
 
         assert(filename);
         assert(lvalue);
         assert(rvalue);
         assert(data);
 
-        dbus_error_init(&error);
+        if (!set_isempty(u->dependencies[UNIT_TRIGGERS])) {
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL,
+                           "Multiple units to trigger specified, ignoring: %s", rvalue);
+                return 0;
+        }
 
-        p = unit_name_printf(UNIT(t), rvalue);
+        p = unit_name_printf(u, rvalue);
         if (!p)
                 return log_oom();
 
-        if (endswith(p, ".timer")) {
+        type = unit_name_to_type(p);
+        if (type < 0) {
                 log_syntax(unit, LOG_ERR, filename, line, EINVAL,
-                           "Unit cannot be of type timer, ignoring: %s", rvalue);
+                           "Unit type not valid, ignoring: %s", rvalue);
                 return 0;
         }
 
-        r = manager_load_unit(UNIT(t)->manager, p, NULL, NULL, &u);
+        if (type == u->type) {
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL,
+                           "Trigger cannot be of same type, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        r = unit_add_two_dependencies_by_name(u, UNIT_BEFORE, UNIT_TRIGGERS, p, NULL, true);
         if (r < 0) {
                 log_syntax(unit, LOG_ERR, filename, line, -r,
-                           "Failed to load unit %s, ignoring: %s",
-                           rvalue, bus_error(&error, r));
-                dbus_error_free(&error);
+                           "Failed to add trigger on %s, ignoring: %s", p, strerror(-r));
                 return 0;
         }
 
-        unit_ref_set(&t->unit, u);
-
         return 0;
 }
 
@@ -1365,53 +1372,6 @@ int config_parse_path_spec(const char *unit,
         return 0;
 }
 
-int config_parse_path_unit(const char *unit,
-                           const char *filename,
-                           unsigned line,
-                           const char *section,
-                           const char *lvalue,
-                           int ltype,
-                           const char *rvalue,
-                           void *data,
-                           void *userdata) {
-
-        Path *t = data;
-        int r;
-        DBusError error;
-        Unit *u;
-        _cleanup_free_ char *p = NULL;
-
-        assert(filename);
-        assert(lvalue);
-        assert(rvalue);
-        assert(data);
-
-        dbus_error_init(&error);
-
-        p = unit_name_printf(UNIT(t), rvalue);
-        if (!p)
-                return log_oom();
-
-        if (endswith(p, ".path")) {
-                log_syntax(unit, LOG_ERR, filename, line, EINVAL,
-                           "Unit cannot be of type path, ignoring: %s", p);
-                return 0;
-        }
-
-        r = manager_load_unit(UNIT(t)->manager, p, NULL, &error, &u);
-        if (r < 0) {
-                log_syntax(unit, LOG_ERR, filename, line, EINVAL,
-                           "Failed to load unit %s, ignoring: %s",
-                           p, bus_error(&error, r));
-                dbus_error_free(&error);
-                return 0;
-        }
-
-        unit_ref_set(&t->unit, u);
-
-        return 0;
-}
-
 int config_parse_socket_service(const char *unit,
                                 const char *filename,
                                 unsigned line,
@@ -2480,10 +2440,9 @@ void unit_dump_config_items(FILE *f) {
                 { config_parse_unit_requires_mounts_for, "PATH [...]" },
                 { config_parse_exec_mount_flags,      "MOUNTFLAG [...]" },
                 { config_parse_unit_string_printf,    "STRING" },
+                { config_parse_trigger_unit,          "UNIT" },
                 { config_parse_timer,                 "TIMER" },
-                { config_parse_timer_unit,            "NAME" },
                 { config_parse_path_spec,             "PATH" },
-                { config_parse_path_unit,             "UNIT" },
                 { config_parse_notify_access,         "ACCESS" },
                 { config_parse_ip_tos,                "TOS" },
                 { config_parse_unit_condition_path,   "CONDITION" },