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         static const UnitDependency deps[] = {
  57                 UNIT_REQUIRES,
  58                 UNIT_REQUIRES_OVERRIDABLE,
  59                 UNIT_REQUISITE,
  60                 UNIT_REQUISITE_OVERRIDABLE,
  61                 UNIT_WANTS,
  62                 UNIT_BIND_TO
  63         };
  64
  65         Iterator i;
  66         Unit *other;
  67         int r;
  68         unsigned k;
  69
  70         assert(t);
  71
  72         /* Imply ordering for requirement dependencies on target
  73          * units. Note that when the user created a contradicting
  74          * ordering manually we won't add anything in here to make
  75          * sure we don't create a loop. */
  76
  77         for (k = 0; k < ELEMENTSOF(deps); k++)
  78                 SET_FOREACH(other, t->meta.dependencies[deps[k]], i)
  79                         if ((r = unit_add_default_target_dependency(other, UNIT(t))) < 0)
  80                                 return r;
  81
  82         /* Make sure targets are unloaded on shutdown */
  83         return unit_add_dependency_by_name(UNIT(t), UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
  84 }
  85
  86 static int target_add_getty_dependencies(Target *t) {
  87         char *n, *active;
  88         int r;
  89
  90         assert(t);
  91
  92         if (!unit_has_name(UNIT(t), SPECIAL_GETTY_TARGET))
  93                 return 0;
  94
  95         if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
  96                 const char *tty;
  97
  98                 truncate_nl(active);
  99                 if ((tty = strrchr(active, ' ')))
 100                         tty ++;
 101                 else
 102                         tty = active;
 103
 104                 /* Automatically add in a serial getty on the kernel
 105                  * console */
 106                 if (!tty_is_vc(tty)) {
 107
 108                         /* We assume that gettys on virtual terminals are
 109                          * started via manual configuration and do this magic
 110                          * only for non-VC terminals. */
 111
 112                         log_debug("Automatically adding serial getty for /dev/%s", tty);
 113                         if (!(n = unit_name_replace_instance(SPECIAL_SERIAL_GETTY_SERVICE, tty))) {
 114                                 free(active);
 115                                 return -ENOMEM;
 116                         }
 117
 118                         r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_WANTS, n, NULL, true);
 119                         free(n);
 120
 121                         if (r < 0) {
 122                                 free(active);
 123                                 return r;
 124                         }
 125                 }
 126
 127                 free(active);
 128         }
 129
 130         /* Automatically add in a serial getty on the first
 131          * virtualizer console */
 132         if (access("/sys/class/tty/hvc0", F_OK) == 0) {
 133                 log_debug("Automatic adding serial getty for hvc0");
 134                 if (!(n = unit_name_replace_instance(SPECIAL_SERIAL_GETTY_SERVICE, "hvc0")))
 135                         return -ENOMEM;
 136
 137                 r = unit_add_two_dependencies_by_name(UNIT(t), UNIT_AFTER, UNIT_WANTS, n, NULL, true);
 138                 free(n);
 139
 140                 if (r < 0)
 141                         return r;
 142         }
 143
 144         return 0;
 145 }
 146
 147 static int target_load(Unit *u) {
 148         Target *t = TARGET(u);
 149         int r;
 150
 151         assert(t);
 152
 153         if ((r = unit_load_fragment_and_dropin(u)) < 0)
 154                 return r;
 155
 156         /* This is a new unit? Then let's add in some extras */
 157         if (u->meta.load_state == UNIT_LOADED) {
 158                 if (u->meta.default_dependencies)
 159                         if ((r = target_add_default_dependencies(t)) < 0)
 160                                 return r;
 161
 162                 if ((r = target_add_getty_dependencies(t)) < 0)
 163                         return r;
 164         }
 165
 166         return 0;
 167 }
 168
 169 static int target_coldplug(Unit *u) {
 170         Target *t = TARGET(u);
 171
 172         assert(t);
 173         assert(t->state == TARGET_DEAD);
 174
 175         if (t->deserialized_state != t->state)
 176                 target_set_state(t, t->deserialized_state);
 177
 178         return 0;
 179 }
 180
 181 static void target_dump(Unit *u, FILE *f, const char *prefix) {
 182         Target *t = TARGET(u);
 183
 184         assert(t);
 185         assert(f);
 186
 187         fprintf(f,
 188                 "%sTarget State: %s\n",
 189                 prefix, target_state_to_string(t->state));
 190 }
 191
 192 static int target_start(Unit *u) {
 193         Target *t = TARGET(u);
 194
 195         assert(t);
 196         assert(t->state == TARGET_DEAD);
 197
 198         target_set_state(t, TARGET_ACTIVE);
 199         return 0;
 200 }
 201
 202 static int target_stop(Unit *u) {
 203         Target *t = TARGET(u);
 204
 205         assert(t);
 206         assert(t->state == TARGET_ACTIVE);
 207
 208         target_set_state(t, TARGET_DEAD);
 209         return 0;
 210 }
 211
 212 static int target_serialize(Unit *u, FILE *f, FDSet *fds) {
 213         Target *s = TARGET(u);
 214
 215         assert(s);
 216         assert(f);
 217         assert(fds);
 218
 219         unit_serialize_item(u, f, "state", target_state_to_string(s->state));
 220         return 0;
 221 }
 222
 223 static int target_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 224         Target *s = TARGET(u);
 225
 226         assert(u);
 227         assert(key);
 228         assert(value);
 229         assert(fds);
 230
 231         if (streq(key, "state")) {
 232                 TargetState state;
 233
 234                 if ((state = target_state_from_string(value)) < 0)
 235                         log_debug("Failed to parse state value %s", value);
 236                 else
 237                         s->deserialized_state = state;
 238
 239         } else
 240                 log_debug("Unknown serialization key '%s'", key);
 241
 242         return 0;
 243 }
 244
 245 static UnitActiveState target_active_state(Unit *u) {
 246         assert(u);
 247
 248         return state_translation_table[TARGET(u)->state];
 249 }
 250
 251 static const char *target_sub_state_to_string(Unit *u) {
 252         assert(u);
 253
 254         return target_state_to_string(TARGET(u)->state);
 255 }
 256
 257 static const char* const target_state_table[_TARGET_STATE_MAX] = {
 258         [TARGET_DEAD] = "dead",
 259         [TARGET_ACTIVE] = "active"
 260 };
 261
 262 DEFINE_STRING_TABLE_LOOKUP(target_state, TargetState);
 263
 264 const UnitVTable target_vtable = {
 265         .suffix = ".target",
 266
 267         .load = target_load,
 268         .coldplug = target_coldplug,
 269
 270         .dump = target_dump,
 271
 272         .start = target_start,
 273         .stop = target_stop,
 274
 275         .serialize = target_serialize,
 276         .deserialize_item = target_deserialize_item,
 277
 278         .active_state = target_active_state,
 279         .sub_state_to_string = target_sub_state_to_string,
 280
 281         .bus_interface = "org.freedesktop.systemd1.Target",
 282         .bus_message_handler = bus_target_message_handler
 283 };