core,systemctl: add new "systemctl revert" command

This allows dropping all user configuration and reverting back to the vendor
default of a unit file. It basically undoes what "systemctl edit", "systemctl
set-property" and "systemctl mask" do.

1 files changed, 52 insertions, 0 deletions

diff --git a/src/test/test-install-root.c b/src/test/test-install-root.c
index bc4206a1b0..2138655e29 100644
--- a/src/test/test-install-root.c
+++ b/src/test/test-install-root.c
@@ -630,6 +630,57 @@ static void test_preset_and_list(const char *root) {
         assert_se(got_yes && got_no);
 }
 
+static void test_revert(const char *root) {
+        const char *p;
+        UnitFileState state;
+        UnitFileChange *changes = NULL;
+        unsigned n_changes = 0;
+
+        assert(root);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "xx.service", NULL) == -ENOENT);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "yy.service", NULL) == -ENOENT);
+
+        p = strjoina(root, "/usr/lib/systemd/system/xx.service");
+        assert_se(write_string_file(p, "# Empty\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "xx.service", NULL) >= 0);
+        assert_se(unit_file_get_state(UNIT_FILE_SYSTEM, root, "xx.service", &state) >= 0 && state == UNIT_FILE_STATIC);
+
+        /* Initially there's nothing to revert */
+        assert_se(unit_file_revert(UNIT_FILE_SYSTEM, root, STRV_MAKE("xx.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 0);
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/xx.service");
+        assert_se(write_string_file(p, "# Empty override\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        /* Revert the override file */
+        assert_se(unit_file_revert(UNIT_FILE_SYSTEM, root, STRV_MAKE("xx.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 1);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        assert_se(streq(changes[0].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/xx.service.d/dropin.conf");
+        assert_se(mkdir_parents(p, 0755) >= 0);
+        assert_se(write_string_file(p, "# Empty dropin\n", WRITE_STRING_FILE_CREATE) >= 0);
+
+        /* Revert the dropin file */
+        assert_se(unit_file_revert(UNIT_FILE_SYSTEM, root, STRV_MAKE("xx.service"), &changes, &n_changes) >= 0);
+        assert_se(n_changes == 2);
+        assert_se(changes[0].type == UNIT_FILE_UNLINK);
+        assert_se(streq(changes[0].path, p));
+
+        p = strjoina(root, SYSTEM_CONFIG_UNIT_PATH"/xx.service.d");
+        assert_se(changes[1].type == UNIT_FILE_UNLINK);
+        assert_se(streq(changes[1].path, p));
+        unit_file_changes_free(changes, n_changes);
+        changes = NULL; n_changes = 0;
+}
+
 int main(int argc, char *argv[]) {
         char root[] = "/tmp/rootXXXXXX";
         const char *p;
@@ -658,6 +709,7 @@ int main(int argc, char *argv[]) {
         test_template_enable(root);
         test_indirect(root);
         test_preset_and_list(root);
+        test_revert(root);
 
         assert_se(rm_rf(root, REMOVE_ROOT|REMOVE_PHYSICAL) >= 0);