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, *active;
  85         int r;
  86
  87         assert(t);
  88
  89         if (!unit_has_name(UNIT(t), SPECIAL_GETTY_TARGET))
  90                 return 0;
  91
  92         if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
  93                 const char *tty;
  94
  95                 truncate_nl(active);
  96                 if ((tty = strrchr(active, ' ')))
  97                         tty ++;
  98                 else
  99                         tty = active;
 100
 101                 /* Automatically add in a serial getty on the kernel
 102                  * console */
 103                 if (!tty_is_vc(tty)) {
 104
 105                         /* We assume that gettys on virtual terminals are
 106                          * started via manual configuration and do this magic
 107                          * only for non-VC terminals. */
 108
 109                         log_debug("Automatically adding serial getty for /dev/%s", tty);
 110                         if (!(n = unit_name_replace_instance(SPECIAL_SERIAL_GETTY_SERVICE, tty))) {
 111                                 free(active);
 112                                 return -ENOMEM;
 113                         }
 114
 115                         r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_WANTS, n, NULL, true);
 116                         free(n);
 117
 118                         if (r < 0) {
 119                                 free(active);
 120                                 return r;
 121                         }
 122                 }
 123
 124                 free(active);
 125         }
 126
 127         /* Automatically add in a serial getty on the first
 128          * virtualizer console */
 129         if (access("/sys/class/tty/hvc0", F_OK) == 0) {
 130                 log_debug("Automatic adding serial getty for hvc0");
 131                 if (!(n = unit_name_replace_instance(SPECIAL_SERIAL_GETTY_SERVICE, "hvc0")))
 132                         return -ENOMEM;
 133
 134                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_WANTS, n, NULL, true);
 135                 free(n);
 136
 137                 if (r < 0)
 138                         return r;
 139         }
 140
 141         return 0;
 142 }
 143
 144 static int target_load(Unit *u) {
 145         Target *t = TARGET(u);
 146         int r;
 147
 148         assert(t);
 149
 150         if ((r = unit_load_fragment_and_dropin(u)) < 0)
 151                 return r;
 152
 153         /* This is a new unit? Then let's add in some extras */
 154         if (u->meta.load_state == UNIT_LOADED) {
 155                 if (u->meta.default_dependencies)
 156                         if ((r = target_add_default_dependencies(t)) < 0)
 157                                 return r;
 158
 159                 if ((r = target_add_getty_dependencies(t)) < 0)
 160                         return r;
 161         }
 162
 163         return 0;
 164 }
 165
 166 static int target_coldplug(Unit *u) {
 167         Target *t = TARGET(u);
 168
 169         assert(t);
 170         assert(t->state == TARGET_DEAD);
 171
 172         if (t->deserialized_state != t->state)
 173                 target_set_state(t, t->deserialized_state);
 174
 175         return 0;
 176 }
 177
 178 static void target_dump(Unit *u, FILE *f, const char *prefix) {
 179         Target *t = TARGET(u);
 180
 181         assert(t);
 182         assert(f);
 183
 184         fprintf(f,
 185                 "%sTarget State: %s\n",
 186                 prefix, target_state_to_string(t->state));
 187 }
 188
 189 static int target_start(Unit *u) {
 190         Target *t = TARGET(u);
 191
 192         assert(t);
 193         assert(t->state == TARGET_DEAD);
 194
 195         target_set_state(t, TARGET_ACTIVE);
 196         return 0;
 197 }
 198
 199 static int target_stop(Unit *u) {
 200         Target *t = TARGET(u);
 201
 202         assert(t);
 203         assert(t->state == TARGET_ACTIVE);
 204
 205         target_set_state(t, TARGET_DEAD);
 206         return 0;
 207 }
 208
 209 static int target_serialize(Unit *u, FILE *f, FDSet *fds) {
 210         Target *s = TARGET(u);
 211
 212         assert(s);
 213         assert(f);
 214         assert(fds);
 215
 216         unit_serialize_item(u, f, "state", target_state_to_string(s->state));
 217         return 0;
 218 }
 219
 220 static int target_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 221         Target *s = TARGET(u);
 222
 223         assert(u);
 224         assert(key);
 225         assert(value);
 226         assert(fds);
 227
 228         if (streq(key, "state")) {
 229                 TargetState state;
 230
 231                 if ((state = target_state_from_string(value)) < 0)
 232                         log_debug("Failed to parse state value %s", value);
 233                 else
 234                         s->deserialized_state = state;
 235
 236         } else
 237                 log_debug("Unknown serialization key '%s'", key);
 238
 239         return 0;
 240 }
 241
 242 static UnitActiveState target_active_state(Unit *u) {
 243         assert(u);
 244
 245         return state_translation_table[TARGET(u)->state];
 246 }
 247
 248 static const char *target_sub_state_to_string(Unit *u) {
 249         assert(u);
 250
 251         return target_state_to_string(TARGET(u)->state);
 252 }
 253
 254 static const char* const target_state_table[_TARGET_STATE_MAX] = {
 255         [TARGET_DEAD] = "dead",
 256         [TARGET_ACTIVE] = "active"
 257 };
 258
 259 DEFINE_STRING_TABLE_LOOKUP(target_state, TargetState);
 260
 261 const UnitVTable target_vtable = {
 262         .suffix = ".target",
 263
 264         .load = target_load,
 265         .coldplug = target_coldplug,
 266
 267         .dump = target_dump,
 268
 269         .start = target_start,
 270         .stop = target_stop,
 271
 272         .serialize = target_serialize,
 273         .deserialize_item = target_deserialize_item,
 274
 275         .active_state = target_active_state,
 276         .sub_state_to_string = target_sub_state_to_string,
 277
 278         .bus_interface = "org.freedesktop.systemd1.Target",
 279         .bus_message_handler = bus_target_message_handler
 280 };