core: when propagating restart requests due to deps, downgrade restart to try-restart

Previously, if a service A depended on a service B via Requires=, and A
was not running and B restarted this would trigger a start of A as well,
since the restart was propagated as restart independently of the state
of A.

This patch ensures that a restart of B would be propagated as a
try-restart to A, thus not changing its state if it isn't up.

http://lists.freedesktop.org/archives/systemd-devel/2015-May/032061.html

src/core/job.c

@@ -388,38 +388,38 @@ bool job_type_is_redundant(JobType a, UnitActiveState b) {
         }
 }
 
-void job_type_collapse(JobType *t, Unit *u) {
+JobType job_type_collapse(JobType t, Unit *u) {
         UnitActiveState s;
 
-        switch (*t) {
+        switch (t) {
 
         case JOB_TRY_RESTART:
                 s = unit_active_state(u);
                 if (UNIT_IS_INACTIVE_OR_DEACTIVATING(s))
-                        *t = JOB_NOP;
+                        return JOB_NOP;
-                else
+
-                        *t = JOB_RESTART;
+                return JOB_RESTART;
-                break;
 
         case JOB_RELOAD_OR_START:
                 s = unit_active_state(u);
                 if (UNIT_IS_INACTIVE_OR_DEACTIVATING(s))
-                        *t = JOB_START;
+                        return JOB_START;
-                else
+
-                        *t = JOB_RELOAD;
+                return JOB_RELOAD;
-                break;
 
         default:
-                ;
+                return t;
         }
 }
 
 int job_type_merge_and_collapse(JobType *a, JobType b, Unit *u) {
-        JobType t = job_type_lookup_merge(*a, b);
+        JobType t;
+
+        t = job_type_lookup_merge(*a, b);
         if (t < 0)
                 return -EEXIST;
-        *a = t;
+
-        job_type_collapse(a, u);
+        *a = job_type_collapse(t, u);
         return 0;
 }
 

src/core/job.h

@@ -206,7 +206,7 @@ bool job_type_is_redundant(JobType a, UnitActiveState b) _pure_;
 
 /* Collapses a state-dependent job type into a simpler type by observing
  * the state of the unit which it is going to be applied to. */
-void job_type_collapse(JobType *t, Unit *u);
+JobType job_type_collapse(JobType t, Unit *u);
 
 int job_type_merge_and_collapse(JobType *a, JobType b, Unit *u);
 

src/core/manager.c

@@ -1204,7 +1204,7 @@ int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool ove
 
         log_unit_debug(unit, "Trying to enqueue job %s/%s/%s", unit->id, job_type_to_string(type), job_mode_to_string(mode));
 
-        job_type_collapse(&type, unit);
+        type = job_type_collapse(type, unit);
 
         tr = transaction_new(mode == JOB_REPLACE_IRREVERSIBLY);
         if (!tr)

src/core/transaction.c

@@ -861,8 +861,7 @@ int transaction_add_job_and_dependencies(
         /*           by ? job_type_to_string(by->type) : "NA"); */
 
         if (!IN_SET(unit->load_state, UNIT_LOADED, UNIT_ERROR, UNIT_NOT_FOUND, UNIT_MASKED))
-                return sd_bus_error_setf(e, BUS_ERROR_LOAD_FAILED,
+                return sd_bus_error_setf(e, BUS_ERROR_LOAD_FAILED, "Unit %s is not loaded properly.", unit->id);
-                                         "Unit %s is not loaded properly.", unit->id);
 
         if (type != JOB_STOP && unit->load_state == UNIT_ERROR) {
                 if (unit->load_error == -ENOENT || unit->manager->test_run)
@@ -1023,12 +1022,18 @@ int transaction_add_job_and_dependencies(
                                 UNIT_CONSISTS_OF,
                         };
 
+                        JobType ptype;
                         unsigned j;
 
+                        /* We propagate STOP as STOP, but RESTART only
+                         * as TRY_RESTART, in order not to start
+                         * dependencies that are not around. */
+                        ptype = type == JOB_RESTART ? JOB_TRY_RESTART : type;
+
                         for (j = 0; j < ELEMENTSOF(propagate_deps); j++)
                                 SET_FOREACH(dep, ret->unit->dependencies[propagate_deps[j]], i) {
 
-                                        r = transaction_add_job_and_dependencies(tr, type, dep, ret, true, override, false, false, ignore_order, e);
+                                        r = transaction_add_job_and_dependencies(tr, job_type_collapse(ptype, dep), dep, ret, true, override, false, false, ignore_order, e);
                                         if (r < 0) {
                                                 if (r != -EBADR)
                                                         goto fail;