1 files changed, 160 insertions, 0 deletions
diff --git a/src/systemctl/systemctl-set-default.c b/src/systemctl/systemctl-set-default.c
new file mode 100644
index 0000000..7ddba17
--- /dev/null
+++ b/src/systemctl/systemctl-set-default.c
@@ -0,0 +1,160 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-error.h"
+#include "bus-locator.h"
+#include "proc-cmdline.h"
+#include "systemctl-daemon-reload.h"
+#include "systemctl-set-default.h"
+#include "systemctl-util.h"
+#include "systemctl.h"
+
+static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
+        char **ret = data;
+
+        if (streq(key, "systemd.unit")) {
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+                if (!unit_name_is_valid(value, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE)) {
+                        log_warning("Unit name specified on %s= is not valid, ignoring: %s", key, value);
+                        return 0;
+                }
+
+                return free_and_strdup_warn(ret, key);
+
+        } else if (!value) {
+                if (runlevel_to_target(key))
+                        return free_and_strdup_warn(ret, key);
+        }
+
+        return 0;
+}
+
+static void emit_cmdline_warning(void) {
+        if (arg_quiet || arg_root)
+                /* don't bother checking the commandline if we're operating on a container */
+                return;
+
+        _cleanup_free_ char *override = NULL;
+        int r;
+
+        r = proc_cmdline_parse(parse_proc_cmdline_item, &override, 0);
+        if (r < 0)
+                log_debug_errno(r, "Failed to parse kernel command line, ignoring: %m");
+        if (override)
+                log_notice("Note: found \"%s\" on the kernel commandline, which overrides the default unit.",
+                           override);
+}
+
+static int determine_default(char **ret_name) {
+        int r;
+
+        if (install_client_side()) {
+                r = unit_file_get_default(arg_scope, arg_root, ret_name);
+                if (r == -ERFKILL)
+                        return log_error_errno(r, "Failed to get default target: Unit file is masked.");
+                if (r < 0)
+                        return log_error_errno(r, "Failed to get default target: %m");
+                return 0;
+
+        } else {
+                sd_bus *bus;
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                const char *name;
+
+                r = acquire_bus(BUS_MANAGER, &bus);
+                if (r < 0)
+                        return r;
+
+                r = bus_call_method(bus, bus_systemd_mgr, "GetDefaultTarget", &error, &reply, NULL);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to get default target: %s", bus_error_message(&error, r));
+
+                r = sd_bus_message_read(reply, "s", &name);
+                if (r < 0)
+                        return bus_log_parse_error(r);
+
+                return free_and_strdup_warn(ret_name, name);
+        }
+}
+
+int verb_get_default(int argc, char *argv[], void *userdata) {
+        _cleanup_free_ char *name = NULL;
+        int r;
+
+        r = determine_default(&name);
+        if (r < 0)
+                return r;
+
+        printf("%s\n", name);
+
+        emit_cmdline_warning();
+
+        return 0;
+}
+
+int verb_set_default(int argc, char *argv[], void *userdata) {
+        _cleanup_free_ char *unit = NULL;
+        InstallChange *changes = NULL;
+        size_t n_changes = 0;
+        int r;
+
+        assert(argc >= 2);
+        assert(argv);
+
+        r = unit_name_mangle_with_suffix(argv[1], "set-default",
+                                         arg_quiet ? 0 : UNIT_NAME_MANGLE_WARN,
+                                         ".target", &unit);
+        if (r < 0)
+                return log_error_errno(r, "Failed to mangle unit name: %m");
+
+        if (install_client_side()) {
+                r = unit_file_set_default(arg_scope, UNIT_FILE_FORCE, arg_root, unit, &changes, &n_changes);
+                install_changes_dump(r, "set default", changes, n_changes, arg_quiet);
+                if (r < 0)
+                        goto finish;
+        } else {
+                _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+                _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+                sd_bus *bus;
+
+                polkit_agent_open_maybe();
+
+                r = acquire_bus(BUS_MANAGER, &bus);
+                if (r < 0)
+                        return r;
+
+                r = bus_call_method(bus, bus_systemd_mgr, "SetDefaultTarget", &error, &reply, "sb", unit, 1);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to set default target: %s", bus_error_message(&error, r));
+
+                r = bus_deserialize_and_dump_unit_file_changes(reply, arg_quiet, &changes, &n_changes);
+                if (r < 0)
+                        goto finish;
+
+                /* Try to reload if enabled */
+                if (!arg_no_reload) {
+                        r = daemon_reload(ACTION_RELOAD, /* graceful= */ false);
+                        if (r < 0)
+                                goto finish;
+                }
+        }
+
+        emit_cmdline_warning();
+
+        if (!arg_quiet) {
+                _cleanup_free_ char *final = NULL;
+
+                r = determine_default(&final);
+                if (r < 0)
+                        goto finish;
+
+                if (!streq(final, unit))
+                        log_notice("Note: \"%s\" is the default unit (possibly a runtime override).", final);
+        }
+
+finish:
+        install_changes_free(changes, n_changes);
+
+        return r < 0 ? r : 0;
+}