core: generalize how we acquire the Unit objects for unit names in bus calls

This splits out the code that translates a unit name into a Unit* object
from method_get_unit(), and reuses it all other functions that operate
similar to it. This effectively means all those calls now optionally
take an empty unit string which now means the same as the client's unit.
This useful behaviour of the GetUnit() bus call is thus extended to all
other matching bus calls.

Similar, the same logic from method_load_unit() is also generalized and
reused wherever appropriate.

1 files changed, 62 insertions, 45 deletions

diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index 4fe374867c..945645c6b1 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -372,21 +372,16 @@ static int property_get_timer_slack_nsec(
         return sd_bus_message_append(reply, "t", (uint64_t) prctl(PR_GET_TIMERSLACK));
 }
 
-static int method_get_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
-        _cleanup_free_ char *path = NULL;
-        Manager *m = userdata;
-        const char *name;
+static int bus_get_unit_by_name(Manager *m, sd_bus_message *message, const char *name, Unit **ret_unit, sd_bus_error *error) {
         Unit *u;
         int r;
 
-        assert(message);
         assert(m);
+        assert(message);
+        assert(ret_unit);
 
-        /* Anyone can call this method */
-
-        r = sd_bus_message_read(message, "s", &name);
-        if (r < 0)
-                return r;
+        /* More or less a wrapper around manager_get_unit() that generates nice errors and has one trick up its sleeve:
+         * if the name is specified empty we use the client's unit. */
 
         if (isempty(name)) {
                 _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
@@ -409,6 +404,43 @@ static int method_get_unit(sd_bus_message *message, void *userdata, sd_bus_error
                         return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s not loaded.", name);
         }
 
+        *ret_unit = u;
+        return 0;
+}
+
+static int bus_load_unit_by_name(Manager *m, sd_bus_message *message, const char *name, Unit **ret_unit, sd_bus_error *error) {
+        assert(m);
+        assert(message);
+        assert(ret_unit);
+
+        /* Pretty much the same as bus_get_unit_by_name(), but we also load the unit if necessary. */
+
+        if (isempty(name))
+                return bus_get_unit_by_name(m, message, name, ret_unit, error);
+
+        return manager_load_unit(m, name, NULL, error, ret_unit);
+}
+
+static int method_get_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        _cleanup_free_ char *path = NULL;
+        Manager *m = userdata;
+        const char *name;
+        Unit *u;
+        int r;
+
+        assert(message);
+        assert(m);
+
+        /* Anyone can call this method */
+
+        r = sd_bus_message_read(message, "s", &name);
+        if (r < 0)
+                return r;
+
+        r = bus_get_unit_by_name(m, message, name, &u, error);
+        if (r < 0)
+                return r;
+
         r = mac_selinux_unit_access_check(u, message, "status", error);
         if (r < 0)
                 return r;
@@ -541,26 +573,9 @@ static int method_load_unit(sd_bus_message *message, void *userdata, sd_bus_erro
         if (r < 0)
                 return r;
 
-        if (isempty(name)) {
-                _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
-                pid_t pid;
-
-                r = sd_bus_query_sender_creds(message, SD_BUS_CREDS_PID, &creds);
-                if (r < 0)
-                        return r;
-
-                r = sd_bus_creds_get_pid(creds, &pid);
-                if (r < 0)
-                        return r;
-
-                u = manager_get_unit_by_pid(m, pid);
-                if (!u)
-                        return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Client not member of any unit.");
-        } else {
-                r = manager_load_unit(m, name, NULL, error, &u);
-                if (r < 0)
-                        return r;
-        }
+        r = bus_load_unit_by_name(m, message, name, &u, error);
+        if (r < 0)
+                return r;
 
         r = mac_selinux_unit_access_check(u, message, "status", error);
         if (r < 0)
@@ -633,8 +648,10 @@ static int method_start_unit_replace(sd_bus_message *message, void *userdata, sd
         if (r < 0)
                 return r;
 
-        u = manager_get_unit(m, old_name);
-        if (!u || !u->job || u->job->type != JOB_START)
+        r = bus_get_unit_by_name(m, message, old_name, &u, error);
+        if (r < 0)
+                return r;
+        if (!u->job || u->job->type != JOB_START)
                 return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_JOB, "No job queued for unit %s", old_name);
 
         return method_start_unit_generic(message, m, JOB_START, false, error);
@@ -653,9 +670,9 @@ static int method_kill_unit(sd_bus_message *message, void *userdata, sd_bus_erro
         if (r < 0)
                 return r;
 
-        u = manager_get_unit(m, name);
-        if (!u)
-                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s is not loaded.", name);
+        r = bus_get_unit_by_name(m, message, name, &u, error);
+        if (r < 0)
+                return r;
 
         return bus_unit_method_kill(message, u, error);
 }
@@ -673,9 +690,9 @@ static int method_reset_failed_unit(sd_bus_message *message, void *userdata, sd_
         if (r < 0)
                 return r;
 
-        u = manager_get_unit(m, name);
-        if (!u)
-                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s is not loaded.", name);
+        r = bus_get_unit_by_name(m, message, name, &u, error);
+        if (r < 0)
+                return r;
 
         return bus_unit_method_reset_failed(message, u, error);
 }
@@ -693,7 +710,7 @@ static int method_set_unit_properties(sd_bus_message *message, void *userdata, s
         if (r < 0)
                 return r;
 
-        r = manager_load_unit(m, name, NULL, error, &u);
+        r = bus_load_unit_by_name(m, message, name, &u, error);
         if (r < 0)
                 return r;
 
@@ -717,7 +734,7 @@ static int method_ref_unit(sd_bus_message *message, void *userdata, sd_bus_error
         if (r < 0)
                 return r;
 
-        r = manager_load_unit(m, name, NULL, error, &u);
+        r = bus_load_unit_by_name(m, message, name, &u, error);
         if (r < 0)
                 return r;
 
@@ -741,7 +758,7 @@ static int method_unref_unit(sd_bus_message *message, void *userdata, sd_bus_err
         if (r < 0)
                 return r;
 
-        r = manager_load_unit(m, name, NULL, error, &u);
+        r = bus_load_unit_by_name(m, message, name, &u, error);
         if (r < 0)
                 return r;
 
@@ -810,7 +827,7 @@ static int method_list_units_by_names(sd_bus_message *message, void *userdata, s
                 if (!unit_name_is_valid(*unit, UNIT_NAME_ANY))
                         continue;
 
-                r = manager_load_unit(m, *unit, NULL, error, &u);
+                r = bus_load_unit_by_name(m, message, *unit, &u, error);
                 if (r < 0)
                         return r;
 
@@ -839,9 +856,9 @@ static int method_get_unit_processes(sd_bus_message *message, void *userdata, sd
         if (r < 0)
                 return r;
 
-        u = manager_get_unit(m, name);
-        if (!u)
-                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_UNIT, "Unit %s not loaded.", name);
+        r = bus_get_unit_by_name(m, message, name, &u, error);
+        if (r < 0)
+                return r;
 
         return bus_unit_method_get_processes(message, u, error);
 }