Do not report masked units as changed (#2921)

* core/unit: extract checking of stat paths into helper function

The same code was repeated three times.

* core: treat masked files as "unchanged"

systemctl prints the "unit file changed on disk" warning
for a masked unit. I think it's better to print nothing in that
case.

When a masked unit is loaded, set mtime as 0. When checking
if a unit with mtime of 0 needs reload, check that the mask
is still in place.

* test-dnssec: fix build without gcrypt

Also reorder the test functions to follow the way they are called
from main().

2 files changed, 33 insertions, 37 deletions

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index d078924c5b..f1a874cfdf 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -3620,10 +3620,12 @@ static int load_from_path(Unit *u, const char *path) {
         if (fstat(fileno(f), &st) < 0)
                 return -errno;
 
-        if (null_or_empty(&st))
+        if (null_or_empty(&st)) {
                 u->load_state = UNIT_MASKED;
-        else {
+                u->fragment_mtime = 0;
+        } else {
                 u->load_state = UNIT_LOADED;
+                u->fragment_mtime = timespec_load(&st.st_mtim);
 
                 /* Now, parse the file contents */
                 r = config_parse(u->id, filename, f,
@@ -3638,8 +3640,6 @@ static int load_from_path(Unit *u, const char *path) {
         u->fragment_path = filename;
         filename = NULL;
 
-        u->fragment_mtime = timespec_load(&st.st_mtim);
-
         if (u->source_path) {
                 if (stat(u->source_path, &st) >= 0)
                         u->source_mtime = timespec_load(&st.st_mtim);
diff --git a/src/core/unit.c b/src/core/unit.c
index af38beb0c3..70175557f7 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2924,34 +2924,36 @@ int unit_coldplug(Unit *u) {
         return 0;
 }
 
+static bool fragment_mtime_changed(const char *path, usec_t mtime) {
+        struct stat st;
+
+        if (!path)
+                return false;
+
+        if (stat(path, &st) < 0)
+                /* What, cannot access this anymore? */
+                return true;
+
+        if (mtime > 0)
+                /* For non-empty files check the mtime */
+                return timespec_load(&st.st_mtim) != mtime;
+        else if (!null_or_empty(&st))
+                /* For masked files check if they are still so */
+                return true;
+
+        return false;
+}
+
 bool unit_need_daemon_reload(Unit *u) {
         _cleanup_strv_free_ char **t = NULL;
         char **path;
-        struct stat st;
         unsigned loaded_cnt, current_cnt;
 
         assert(u);
 
-        if (u->fragment_path) {
-                zero(st);
-                if (stat(u->fragment_path, &st) < 0)
-                        /* What, cannot access this anymore? */
-                        return true;
-
-                if (u->fragment_mtime > 0 &&
-                    timespec_load(&st.st_mtim) != u->fragment_mtime)
-                        return true;
-        }
-
-        if (u->source_path) {
-                zero(st);
-                if (stat(u->source_path, &st) < 0)
-                        return true;
-
-                if (u->source_mtime > 0 &&
-                    timespec_load(&st.st_mtim) != u->source_mtime)
-                        return true;
-        }
+        if (fragment_mtime_changed(u->fragment_path, u->fragment_mtime) ||
+            fragment_mtime_changed(u->source_path, u->source_mtime))
+                return true;
 
         (void) unit_find_dropin_paths(u, &t);
         loaded_cnt = strv_length(t);
@@ -2962,21 +2964,15 @@ bool unit_need_daemon_reload(Unit *u) {
                         return false;
 
                 if (strv_overlap(u->dropin_paths, t)) {
-                        STRV_FOREACH(path, u->dropin_paths) {
-                                zero(st);
-                                if (stat(*path, &st) < 0)
-                                        return true;
-
-                                if (u->dropin_mtime > 0 &&
-                                    timespec_load(&st.st_mtim) > u->dropin_mtime)
+                        STRV_FOREACH(path, u->dropin_paths)
+                                if (fragment_mtime_changed(*path, u->dropin_mtime))
                                         return true;
-                        }
 
                         return false;
-                } else
-                        return true;
-        } else
-                return true;
+                }
+        }
+
+        return true;
 }
 
 void unit_reset_failed(Unit *u) {