src/core/target.c

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