systemctl/core: ignore masked units in preset-all

With any masked unit that would that would be enabled by presets, we'd get:

test@rawhide $ sudo systemctl preset-all
Failed to execute operation: Unit file is masked.

test@rawhide $ sudo systemctl --root=/ preset-all
Operation failed: Cannot send after transport endpoint shutdown

Simply ignore those units:

test@rawhide $ sudo systemctl preset-all
Unit xxx.service is masked, ignoring.

5 files changed, 36 insertions, 11 deletions

diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index 0b12aae2ef..9a913a6c91 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -1565,11 +1565,13 @@ static int reply_unit_file_changes_and_free(
         unsigned i;
         int r;
 
-        if (n_changes > 0) {
-                r = bus_foreach_bus(m, NULL, send_unit_files_changed, NULL);
-                if (r < 0)
-                        log_debug_errno(r, "Failed to send UnitFilesChanged signal: %m");
-        }
+        for (i = 0; i < n_changes; i++)
+                if (unit_file_change_is_modification(changes[i].type)) {
+                        r = bus_foreach_bus(m, NULL, send_unit_files_changed, NULL);
+                        if (r < 0)
+                                log_debug_errno(r, "Failed to send UnitFilesChanged signal: %m");
+                        break;
+                }
 
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
diff --git a/src/shared/bus-util.c b/src/shared/bus-util.c
index 2b86b1fcd6..677970b7f0 100644
--- a/src/shared/bus-util.c
+++ b/src/shared/bus-util.c
@@ -2203,11 +2203,17 @@ int bus_deserialize_and_dump_unit_file_changes(sd_bus_message *m, bool quiet, Un
                 if (!quiet) {
                         if (streq(type, "symlink"))
                                 log_info("Created symlink from %s to %s.", path, source);
-                        else
+                        else if (streq(type, "unlink"))
                                 log_info("Removed symlink %s.", path);
+                        else if (streq(type, "masked"))
+                                log_info("Unit %s is masked, ignoring.", path);
+                        else
+                                log_notice("Manager reported unknown change type \"%s\" for %s.", type, path);
                 }
 
-                r = unit_file_changes_add(changes, n_changes, streq(type, "symlink") ? UNIT_FILE_SYMLINK : UNIT_FILE_UNLINK, path, source);
+                r = unit_file_changes_add(changes, n_changes,
+                                          unit_file_change_type_from_string(type),
+                                          path, source);
                 if (r < 0)
                         return r;
         }
diff --git a/src/shared/install.c b/src/shared/install.c
index 35d83dd16c..74de8141f1 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -2539,6 +2539,9 @@ int unit_file_preset_all(
                                 continue;
 
                         r = preset_prepare_one(scope, &plus, &minus, &paths, mode, de->d_name);
+                        if (r == -ERFKILL)
+                                r = unit_file_changes_add(changes, n_changes,
+                                                          UNIT_FILE_IS_MASKED, de->d_name, NULL);
                         if (r < 0)
                                 return r;
                 }
@@ -2652,6 +2655,7 @@ DEFINE_STRING_TABLE_LOOKUP(unit_file_state, UnitFileState);
 static const char* const unit_file_change_type_table[_UNIT_FILE_CHANGE_TYPE_MAX] = {
         [UNIT_FILE_SYMLINK] = "symlink",
         [UNIT_FILE_UNLINK] = "unlink",
+        [UNIT_FILE_IS_MASKED] = "masked",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(unit_file_change_type, UnitFileChangeType);
diff --git a/src/shared/install.h b/src/shared/install.h
index 6f8b45d4f6..6b760def9b 100644
--- a/src/shared/install.h
+++ b/src/shared/install.h
@@ -72,10 +72,15 @@ enum UnitFilePresetMode {
 enum UnitFileChangeType {
         UNIT_FILE_SYMLINK,
         UNIT_FILE_UNLINK,
+        UNIT_FILE_IS_MASKED,
         _UNIT_FILE_CHANGE_TYPE_MAX,
         _UNIT_FILE_CHANGE_TYPE_INVALID = -1
 };
 
+static inline bool unit_file_change_is_modification(UnitFileChangeType type) {
+        return IN_SET(type, UNIT_FILE_SYMLINK, UNIT_FILE_UNLINK);
+}
+
 struct UnitFileChange {
         UnitFileChangeType type;
         char *path;
diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index 4942dbb6ad..0c64cbab80 100644
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -1989,12 +1989,20 @@ static void dump_unit_file_changes(const UnitFileChange *changes, unsigned n_cha
 
         assert(changes || n_changes == 0);
 
-        for (i = 0; i < n_changes; i++) {
-                if (changes[i].type == UNIT_FILE_SYMLINK)
+        for (i = 0; i < n_changes; i++)
+                switch(changes[i].type) {
+                case UNIT_FILE_SYMLINK:
                         log_info("Created symlink %s, pointing to %s.", changes[i].path, changes[i].source);
-                else
+                        break;
+                case UNIT_FILE_UNLINK:
                         log_info("Removed %s.", changes[i].path);
-        }
+                        break;
+                case UNIT_FILE_IS_MASKED:
+                        log_info("Unit %s is masked, ignoring.", changes[i].path);
+                        break;
+                default:
+                        assert_not_reached("bad change type");
+                }
 }
 
 static int set_default(int argc, char *argv[], void *userdata) {