src/core/target.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "dbus-target.h"
   4 #include "dbus-unit.h"
   5 #include "log.h"
   6 #include "serialize.h"
   7 #include "special.h"
   8 #include "string-util.h"
   9 #include "target.h"
  10 #include "unit-name.h"
  11 #include "unit.h"
  12
  13 static const UnitActiveState state_translation_table[_TARGET_STATE_MAX] = {
  14         [TARGET_DEAD] = UNIT_INACTIVE,
  15         [TARGET_ACTIVE] = UNIT_ACTIVE
  16 };
  17
  18 static void target_set_state(Target *t, TargetState state) {
  19         TargetState old_state;
  20         assert(t);
  21
  22         if (t->state != state)
  23                 bus_unit_send_pending_change_signal(UNIT(t), false);
  24
  25         old_state = t->state;
  26         t->state = state;
  27
  28         if (state != old_state)
  29                 log_debug("%s changed %s -> %s",
  30                           UNIT(t)->id,
  31                           target_state_to_string(old_state),
  32                           target_state_to_string(state));
  33
  34         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], /* reload_success = */ true);
  35 }
  36
  37 static int target_add_default_dependencies(Target *t) {
  38         _cleanup_free_ Unit **others = NULL;
  39         int r, n_others;
  40
  41         assert(t);
  42
  43         if (!UNIT(t)->default_dependencies)
  44                 return 0;
  45
  46         /* Imply ordering for requirement dependencies on target units. Note that when the user created a
  47          * contradicting ordering manually we won't add anything in here to make sure we don't create a
  48          * loop.
  49          *
  50          * Note that quite likely iterating through these dependencies will add new dependencies, which
  51          * conflicts with the hashmap-based iteration logic. Hence, instead of iterating through the
  52          * dependencies and acting on them as we go, first take an "atomic snapshot" of sorts and iterate
  53          * through that. */
  54
  55         n_others = unit_get_dependency_array(UNIT(t), UNIT_ATOM_ADD_DEFAULT_TARGET_DEPENDENCY_QUEUE, &others);
  56         if (n_others < 0)
  57                 return n_others;
  58
  59         for (int i = 0; i < n_others; i++) {
  60                 r = unit_add_default_target_dependency(others[i], UNIT(t));
  61                 if (r < 0)
  62                         return r;
  63         }
  64
  65         if (unit_has_name(UNIT(t), SPECIAL_SHUTDOWN_TARGET))
  66                 return 0;
  67
  68         /* Make sure targets are unloaded on shutdown */
  69         if (!UNIT(t)->ignore_on_soft_reboot)
  70                 return unit_add_two_dependencies_by_name(
  71                                 UNIT(t),
  72                                 UNIT_BEFORE, UNIT_CONFLICTS,
  73                                 SPECIAL_SHUTDOWN_TARGET, true,
  74                                 UNIT_DEPENDENCY_DEFAULT);
  75
  76         /* Unless we are meant to survive soft reboot, in which case we need to conflict with
  77          * non-soft-reboot targets. */
  78         return unit_add_dependencies_on_real_shutdown_targets(UNIT(t));
  79 }
  80
  81 static int target_load(Unit *u) {
  82         Target *t = TARGET(u);
  83         int r;
  84
  85         assert(t);
  86
  87         r = unit_load_fragment_and_dropin(u, true);
  88         if (r < 0)
  89                 return r;
  90
  91         if (u->load_state != UNIT_LOADED)
  92                 return 0;
  93
  94         /* This is a new unit? Then let's add in some extras */
  95         return target_add_default_dependencies(t);
  96 }
  97
  98 static int target_coldplug(Unit *u) {
  99         Target *t = TARGET(u);
 100
 101         assert(t);
 102         assert(t->state == TARGET_DEAD);
 103
 104         if (t->deserialized_state != t->state)
 105                 target_set_state(t, t->deserialized_state);
 106
 107         return 0;
 108 }
 109
 110 static void target_dump(Unit *u, FILE *f, const char *prefix) {
 111         Target *t = TARGET(u);
 112
 113         assert(t);
 114         assert(f);
 115
 116         fprintf(f,
 117                 "%sTarget State: %s\n",
 118                 prefix, target_state_to_string(t->state));
 119 }
 120
 121 static int target_start(Unit *u) {
 122         Target *t = TARGET(u);
 123         int r;
 124
 125         assert(t);
 126         assert(t->state == TARGET_DEAD);
 127
 128         r = unit_acquire_invocation_id(u);
 129         if (r < 0)
 130                 return r;
 131
 132         target_set_state(t, TARGET_ACTIVE);
 133         return 1;
 134 }
 135
 136 static int target_stop(Unit *u) {
 137         Target *t = TARGET(u);
 138
 139         assert(t);
 140         assert(t->state == TARGET_ACTIVE);
 141
 142         target_set_state(t, TARGET_DEAD);
 143         return 1;
 144 }
 145
 146 static int target_serialize(Unit *u, FILE *f, FDSet *fds) {
 147         Target *s = TARGET(u);
 148
 149         assert(s);
 150         assert(f);
 151         assert(fds);
 152
 153         (void) serialize_item(f, "state", target_state_to_string(s->state));
 154         return 0;
 155 }
 156
 157 static int target_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 158         Target *s = TARGET(u);
 159
 160         assert(s);
 161         assert(u);
 162         assert(key);
 163         assert(value);
 164         assert(fds);
 165
 166         if (streq(key, "state")) {
 167                 TargetState state;
 168
 169                 state = target_state_from_string(value);
 170                 if (state < 0)
 171                         log_debug("Failed to parse state value %s", value);
 172                 else
 173                         s->deserialized_state = state;
 174
 175         } else
 176                 log_debug("Unknown serialization key '%s'", key);
 177
 178         return 0;
 179 }
 180
 181 _pure_ static UnitActiveState target_active_state(Unit *u) {
 182         assert(u);
 183
 184         return state_translation_table[TARGET(u)->state];
 185 }
 186
 187 _pure_ static const char *target_sub_state_to_string(Unit *u) {
 188         assert(u);
 189
 190         return target_state_to_string(TARGET(u)->state);
 191 }
 192
 193 const UnitVTable target_vtable = {
 194         .object_size = sizeof(Target),
 195
 196         .sections =
 197                 "Unit\0"
 198                 "Target\0"
 199                 "Install\0",
 200
 201         .can_fail = true,
 202
 203         .load = target_load,
 204         .coldplug = target_coldplug,
 205
 206         .dump = target_dump,
 207
 208         .start = target_start,
 209         .stop = target_stop,
 210
 211         .serialize = target_serialize,
 212         .deserialize_item = target_deserialize_item,
 213
 214         .active_state = target_active_state,
 215         .sub_state_to_string = target_sub_state_to_string,
 216
 217         .status_message_formats = {
 218                 .finished_start_job = {
 219                         [JOB_DONE]       = "Reached target %s.",
 220                 },
 221                 .finished_stop_job = {
 222                         [JOB_DONE]       = "Stopped target %s.",
 223                 },
 224         },
 225 };