src/systemctl/systemctl-set-default.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "bus-error.h"
   4 #include "bus-locator.h"
   5 #include "proc-cmdline.h"
   6 #include "systemctl-daemon-reload.h"
   7 #include "systemctl-set-default.h"
   8 #include "systemctl-util.h"
   9 #include "systemctl.h"
  10
  11 static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
  12         char **ret = data;
  13
  14         if (streq(key, "systemd.unit")) {
  15                 if (proc_cmdline_value_missing(key, value))
  16                         return 0;
  17                 if (!unit_name_is_valid(value, UNIT_NAME_PLAIN|UNIT_NAME_INSTANCE)) {
  18                         log_warning("Unit name specified on %s= is not valid, ignoring: %s", key, value);
  19                         return 0;
  20                 }
  21
  22                 return free_and_strdup_warn(ret, key);
  23
  24         } else if (!value) {
  25                 if (runlevel_to_target(key))
  26                         return free_and_strdup_warn(ret, key);
  27         }
  28
  29         return 0;
  30 }
  31
  32 static void emit_cmdline_warning(void) {
  33         if (arg_quiet || arg_root)
  34                 /* don't bother checking the commandline if we're operating on a container */
  35                 return;
  36
  37         _cleanup_free_ char *override = NULL;
  38         int r;
  39
  40         r = proc_cmdline_parse(parse_proc_cmdline_item, &override, 0);
  41         if (r < 0)
  42                 log_debug_errno(r, "Failed to parse kernel command line, ignoring: %m");
  43         if (override)
  44                 log_notice("Note: found \"%s\" on the kernel commandline, which overrides the default unit.",
  45                            override);
  46 }
  47
  48 static int determine_default(char **ret_name) {
  49         int r;
  50
  51         if (install_client_side()) {
  52                 r = unit_file_get_default(arg_runtime_scope, arg_root, ret_name);
  53                 if (r == -ERFKILL)
  54                         return log_error_errno(r, "Failed to get default target: Unit file is masked.");
  55                 if (r < 0)
  56                         return log_error_errno(r, "Failed to get default target: %m");
  57                 return 0;
  58
  59         } else {
  60                 sd_bus *bus;
  61                 _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
  62                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
  63                 const char *name;
  64
  65                 r = acquire_bus(BUS_MANAGER, &bus);
  66                 if (r < 0)
  67                         return r;
  68
  69                 r = bus_call_method(bus, bus_systemd_mgr, "GetDefaultTarget", &error, &reply, NULL);
  70                 if (r < 0)
  71                         return log_error_errno(r, "Failed to get default target: %s", bus_error_message(&error, r));
  72
  73                 r = sd_bus_message_read(reply, "s", &name);
  74                 if (r < 0)
  75                         return bus_log_parse_error(r);
  76
  77                 return free_and_strdup_warn(ret_name, name);
  78         }
  79 }
  80
  81 int verb_get_default(int argc, char *argv[], void *userdata) {
  82         _cleanup_free_ char *name = NULL;
  83         int r;
  84
  85         r = determine_default(&name);
  86         if (r < 0)
  87                 return r;
  88
  89         printf("%s\n", name);
  90
  91         emit_cmdline_warning();
  92
  93         return 0;
  94 }
  95
  96 int verb_set_default(int argc, char *argv[], void *userdata) {
  97         _cleanup_free_ char *unit = NULL;
  98         InstallChange *changes = NULL;
  99         size_t n_changes = 0;
 100         int r;
 101
 102         assert(argc >= 2);
 103         assert(argv);
 104
 105         r = unit_name_mangle_with_suffix(argv[1], "set-default",
 106                                          arg_quiet ? 0 : UNIT_NAME_MANGLE_WARN,
 107                                          ".target", &unit);
 108         if (r < 0)
 109                 return log_error_errno(r, "Failed to mangle unit name: %m");
 110
 111         if (install_client_side()) {
 112                 r = unit_file_set_default(arg_runtime_scope, UNIT_FILE_FORCE, arg_root, unit, &changes, &n_changes);
 113                 install_changes_dump(r, "set default", changes, n_changes, arg_quiet);
 114                 if (r < 0)
 115                         goto finish;
 116         } else {
 117                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 118                 _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
 119                 sd_bus *bus;
 120
 121                 polkit_agent_open_maybe();
 122
 123                 r = acquire_bus(BUS_MANAGER, &bus);
 124                 if (r < 0)
 125                         return r;
 126
 127                 r = bus_call_method(bus, bus_systemd_mgr, "SetDefaultTarget", &error, &reply, "sb", unit, 1);
 128                 if (r < 0)
 129                         return log_error_errno(r, "Failed to set default target: %s", bus_error_message(&error, r));
 130
 131                 r = bus_deserialize_and_dump_unit_file_changes(reply, arg_quiet, &changes, &n_changes);
 132                 if (r < 0)
 133                         goto finish;
 134
 135                 /* Try to reload if enabled */
 136                 if (!arg_no_reload) {
 137                         r = daemon_reload(ACTION_RELOAD, /* graceful= */ false);
 138                         if (r < 0)
 139                                 goto finish;
 140                 }
 141         }
 142
 143         emit_cmdline_warning();
 144
 145         if (!arg_quiet) {
 146                 _cleanup_free_ char *final = NULL;
 147
 148                 r = determine_default(&final);
 149                 if (r < 0)
 150                         goto finish;
 151
 152                 if (!streq(final, unit))
 153                         log_notice("Note: \"%s\" is the default unit (possibly a runtime override).", final);
 154         }
 155
 156 finish:
 157         install_changes_free(changes, n_changes);
 158
 159         return r < 0 ? r : 0;
 160 }