src/target.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <signal.h>
  24 #include <unistd.h>
  25
  26 #include "unit.h"
  27 #include "target.h"
  28 #include "load-fragment.h"
  29 #include "log.h"
  30 #include "dbus-target.h"
  31 #include "special.h"
  32 #include "unit-name.h"
  33
  34 static const UnitActiveState state_translation_table[_TARGET_STATE_MAX] = {
  35         [TARGET_DEAD] = UNIT_INACTIVE,
  36         [TARGET_ACTIVE] = UNIT_ACTIVE
  37 };
  38
  39 static void target_set_state(Target *t, TargetState state) {
  40         TargetState old_state;
  41         assert(t);
  42
  43         old_state = t->state;
  44         t->state = state;
  45
  46         if (state != old_state)
  47                 log_debug("%s changed %s -> %s",
  48                           t->meta.id,
  49                           target_state_to_string(old_state),
  50                           target_state_to_string(state));
  51
  52         unit_notify(UNIT(t), state_translation_table[old_state], state_translation_table[state], true);
  53 }
  54
  55 static int target_add_default_dependencies(Target *t) {
  56         Iterator i;
  57         Unit *other;
  58         int r;
  59
  60         assert(t);
  61
  62         /* Imply ordering for requirement dependencies on target
  63          * units. Note that when the user created a contradicting
  64          * ordering manually we won't add anything in here to make
  65          * sure we don't create a loop. */
  66
  67         SET_FOREACH(other, t->meta.dependencies[UNIT_REQUIRES], i)
  68                 if ((r = unit_add_default_target_dependency(other, UNIT(t))) < 0)
  69                     return r;
  70
  71         SET_FOREACH(other, t->meta.dependencies[UNIT_REQUIRES_OVERRIDABLE], i)
  72                 if ((r = unit_add_default_target_dependency(other, UNIT(t))) < 0)
  73                     return r;
  74
  75         SET_FOREACH(other, t->meta.dependencies[UNIT_WANTS], i)
  76                 if ((r = unit_add_default_target_dependency(other, UNIT(t))) < 0)
  77                     return r;
  78
  79         /* Make sure targets are unloaded on shutdown */
  80         return unit_add_dependency_by_name(UNIT(t), UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
  81 }
  82
  83 static int target_add_getty_dependencies(Target *t) {
  84         char *n;
  85         int r;
  86
  87         assert(t);
  88
  89         if (!unit_has_name(UNIT(t), SPECIAL_GETTY_TARGET))
  90                 return 0;
  91
  92         /* Automatically add in a serial getty on the kernel
  93          * console */
  94         if (t->meta.manager->console) {
  95                 log_debug("Automatically adding serial getty for %s", t->meta.manager->console);
  96                 if (!(n = unit_name_replace_instance(SPECIAL_SERIAL_GETTY_SERVICE, t->meta.manager->console)))
  97                         return -ENOMEM;
  98
  99                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_WANTS, n, NULL, true);
 100                 free(n);
 101
 102                 if (r < 0)
 103                         return r;
 104         }
 105
 106         /* Automatically add in a serial getty on the first
 107          * virtualizer console */
 108         if (access("/sys/class/tty/hvc0", F_OK) == 0) {
 109                 log_debug("Automatic adding serial getty for hvc0");
 110                 if (!(n = unit_name_replace_instance(SPECIAL_SERIAL_GETTY_SERVICE, "hvc0")))
 111                         return -ENOMEM;
 112
 113                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_WANTS, n, NULL, true);
 114                 free(n);
 115
 116                 if (r < 0)
 117                         return r;
 118         }
 119
 120         return 0;
 121 }
 122
 123 static int target_load(Unit *u) {
 124         Target *t = TARGET(u);
 125         int r;
 126
 127         assert(t);
 128
 129         if ((r = unit_load_fragment_and_dropin(u)) < 0)
 130                 return r;
 131
 132         /* This is a new unit? Then let's add in some extras */
 133         if (u->meta.load_state == UNIT_LOADED) {
 134                 if (u->meta.default_dependencies)
 135                         if ((r = target_add_default_dependencies(t)) < 0)
 136                                 return r;
 137
 138                 if ((r = target_add_getty_dependencies(t)) < 0)
 139                         return r;
 140         }
 141
 142         return 0;
 143 }
 144
 145 static int target_coldplug(Unit *u) {
 146         Target *t = TARGET(u);
 147
 148         assert(t);
 149         assert(t->state == TARGET_DEAD);
 150
 151         if (t->deserialized_state != t->state)
 152                 target_set_state(t, t->deserialized_state);
 153
 154         return 0;
 155 }
 156
 157 static void target_dump(Unit *u, FILE *f, const char *prefix) {
 158         Target *t = TARGET(u);
 159
 160         assert(t);
 161         assert(f);
 162
 163         fprintf(f,
 164                 "%sTarget State: %s\n",
 165                 prefix, target_state_to_string(t->state));
 166 }
 167
 168 static int target_start(Unit *u) {
 169         Target *t = TARGET(u);
 170
 171         assert(t);
 172         assert(t->state == TARGET_DEAD);
 173
 174         target_set_state(t, TARGET_ACTIVE);
 175         return 0;
 176 }
 177
 178 static int target_stop(Unit *u) {
 179         Target *t = TARGET(u);
 180
 181         assert(t);
 182         assert(t->state == TARGET_ACTIVE);
 183
 184         target_set_state(t, TARGET_DEAD);
 185         return 0;
 186 }
 187
 188 static int target_serialize(Unit *u, FILE *f, FDSet *fds) {
 189         Target *s = TARGET(u);
 190
 191         assert(s);
 192         assert(f);
 193         assert(fds);
 194
 195         unit_serialize_item(u, f, "state", target_state_to_string(s->state));
 196         return 0;
 197 }
 198
 199 static int target_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 200         Target *s = TARGET(u);
 201
 202         assert(u);
 203         assert(key);
 204         assert(value);
 205         assert(fds);
 206
 207         if (streq(key, "state")) {
 208                 TargetState state;
 209
 210                 if ((state = target_state_from_string(value)) < 0)
 211                         log_debug("Failed to parse state value %s", value);
 212                 else
 213                         s->deserialized_state = state;
 214
 215         } else
 216                 log_debug("Unknown serialization key '%s'", key);
 217
 218         return 0;
 219 }
 220
 221 static UnitActiveState target_active_state(Unit *u) {
 222         assert(u);
 223
 224         return state_translation_table[TARGET(u)->state];
 225 }
 226
 227 static const char *target_sub_state_to_string(Unit *u) {
 228         assert(u);
 229
 230         return target_state_to_string(TARGET(u)->state);
 231 }
 232
 233 static const char* const target_state_table[_TARGET_STATE_MAX] = {
 234         [TARGET_DEAD] = "dead",
 235         [TARGET_ACTIVE] = "active"
 236 };
 237
 238 DEFINE_STRING_TABLE_LOOKUP(target_state, TargetState);
 239
 240 const UnitVTable target_vtable = {
 241         .suffix = ".target",
 242
 243         .load = target_load,
 244         .coldplug = target_coldplug,
 245
 246         .dump = target_dump,
 247
 248         .start = target_start,
 249         .stop = target_stop,
 250
 251         .serialize = target_serialize,
 252         .deserialize_item = target_deserialize_item,
 253
 254         .active_state = target_active_state,
 255         .sub_state_to_string = target_sub_state_to_string,
 256
 257         .bus_interface = "org.freedesktop.systemd1.Target",
 258         .bus_message_handler = bus_target_message_handler
 259 };