src/core/snapshot.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 Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 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   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23
  24 #include "unit.h"
  25 #include "snapshot.h"
  26 #include "unit-name.h"
  27 #include "dbus-snapshot.h"
  28 #include "bus-errors.h"
  29
  30 static const UnitActiveState state_translation_table[_SNAPSHOT_STATE_MAX] = {
  31         [SNAPSHOT_DEAD] = UNIT_INACTIVE,
  32         [SNAPSHOT_ACTIVE] = UNIT_ACTIVE
  33 };
  34
  35 static void snapshot_init(Unit *u) {
  36         Snapshot *s = SNAPSHOT(u);
  37
  38         assert(s);
  39         assert(UNIT(s)->load_state == UNIT_STUB);
  40
  41         UNIT(s)->ignore_on_isolate = true;
  42         UNIT(s)->ignore_on_snapshot = true;
  43 }
  44
  45 static void snapshot_set_state(Snapshot *s, SnapshotState state) {
  46         SnapshotState old_state;
  47         assert(s);
  48
  49         old_state = s->state;
  50         s->state = state;
  51
  52         if (state != old_state)
  53                 log_debug("%s changed %s -> %s",
  54                           UNIT(s)->id,
  55                           snapshot_state_to_string(old_state),
  56                           snapshot_state_to_string(state));
  57
  58         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], true);
  59 }
  60
  61 static int snapshot_load(Unit *u) {
  62         Snapshot *s = SNAPSHOT(u);
  63
  64         assert(u);
  65         assert(u->load_state == UNIT_STUB);
  66
  67         /* Make sure that only snapshots created via snapshot_create()
  68          * can be loaded */
  69         if (!s->by_snapshot_create && UNIT(s)->manager->n_reloading <= 0)
  70                 return -ENOENT;
  71
  72         u->load_state = UNIT_LOADED;
  73         return 0;
  74 }
  75
  76 static int snapshot_coldplug(Unit *u) {
  77         Snapshot *s = SNAPSHOT(u);
  78
  79         assert(s);
  80         assert(s->state == SNAPSHOT_DEAD);
  81
  82         if (s->deserialized_state != s->state)
  83                 snapshot_set_state(s, s->deserialized_state);
  84
  85         return 0;
  86 }
  87
  88 static void snapshot_dump(Unit *u, FILE *f, const char *prefix) {
  89         Snapshot *s = SNAPSHOT(u);
  90
  91         assert(s);
  92         assert(f);
  93
  94         fprintf(f,
  95                 "%sSnapshot State: %s\n"
  96                 "%sClean Up: %s\n",
  97                 prefix, snapshot_state_to_string(s->state),
  98                 prefix, yes_no(s->cleanup));
  99 }
 100
 101 static int snapshot_start(Unit *u) {
 102         Snapshot *s = SNAPSHOT(u);
 103
 104         assert(s);
 105         assert(s->state == SNAPSHOT_DEAD);
 106
 107         snapshot_set_state(s, SNAPSHOT_ACTIVE);
 108
 109         if (s->cleanup)
 110                 unit_add_to_cleanup_queue(u);
 111
 112         return 0;
 113 }
 114
 115 static int snapshot_stop(Unit *u) {
 116         Snapshot *s = SNAPSHOT(u);
 117
 118         assert(s);
 119         assert(s->state == SNAPSHOT_ACTIVE);
 120
 121         snapshot_set_state(s, SNAPSHOT_DEAD);
 122         return 0;
 123 }
 124
 125 static int snapshot_serialize(Unit *u, FILE *f, FDSet *fds) {
 126         Snapshot *s = SNAPSHOT(u);
 127         Unit *other;
 128         Iterator i;
 129
 130         assert(s);
 131         assert(f);
 132         assert(fds);
 133
 134         unit_serialize_item(u, f, "state", snapshot_state_to_string(s->state));
 135         unit_serialize_item(u, f, "cleanup", yes_no(s->cleanup));
 136         SET_FOREACH(other, u->dependencies[UNIT_WANTS], i)
 137                 unit_serialize_item(u, f, "wants", other->id);
 138
 139         return 0;
 140 }
 141
 142 static int snapshot_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 143         Snapshot *s = SNAPSHOT(u);
 144         int r;
 145
 146         assert(u);
 147         assert(key);
 148         assert(value);
 149         assert(fds);
 150
 151         if (streq(key, "state")) {
 152                 SnapshotState state;
 153
 154                 if ((state = snapshot_state_from_string(value)) < 0)
 155                         log_debug("Failed to parse state value %s", value);
 156                 else
 157                         s->deserialized_state = state;
 158
 159         } else if (streq(key, "cleanup")) {
 160
 161                 if ((r = parse_boolean(value)) < 0)
 162                         log_debug("Failed to parse cleanup value %s", value);
 163                 else
 164                         s->cleanup = r;
 165
 166         } else if (streq(key, "wants")) {
 167
 168                 if ((r = unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_WANTS, value, NULL, true)) < 0)
 169                         return r;
 170         } else
 171                 log_debug("Unknown serialization key '%s'", key);
 172
 173         return 0;
 174 }
 175
 176 static UnitActiveState snapshot_active_state(Unit *u) {
 177         assert(u);
 178
 179         return state_translation_table[SNAPSHOT(u)->state];
 180 }
 181
 182 static const char *snapshot_sub_state_to_string(Unit *u) {
 183         assert(u);
 184
 185         return snapshot_state_to_string(SNAPSHOT(u)->state);
 186 }
 187
 188 int snapshot_create(Manager *m, const char *name, bool cleanup, DBusError *e, Snapshot **_s) {
 189         Iterator i;
 190         Unit *other, *u = NULL;
 191         char *n = NULL;
 192         int r;
 193         const char *k;
 194
 195         assert(m);
 196         assert(_s);
 197
 198         if (name) {
 199                 if (!unit_name_is_valid(name, false)) {
 200                         dbus_set_error(e, BUS_ERROR_INVALID_NAME, "Unit name %s is not valid.", name);
 201                         return -EINVAL;
 202                 }
 203
 204                 if (unit_name_to_type(name) != UNIT_SNAPSHOT) {
 205                         dbus_set_error(e, BUS_ERROR_UNIT_TYPE_MISMATCH, "Unit name %s lacks snapshot suffix.", name);
 206                         return -EINVAL;
 207                 }
 208
 209                 if (manager_get_unit(m, name)) {
 210                         dbus_set_error(e, BUS_ERROR_UNIT_EXISTS, "Snapshot %s exists already.", name);
 211                         return -EEXIST;
 212                 }
 213
 214         } else {
 215
 216                 for (;;) {
 217                         if (asprintf(&n, "snapshot-%u.snapshot", ++ m->n_snapshots) < 0)
 218                                 return -ENOMEM;
 219
 220                         if (!manager_get_unit(m, n))
 221                                 break;
 222
 223                         free(n);
 224                 }
 225
 226                 name = n;
 227         }
 228
 229         r = manager_load_unit_prepare(m, name, NULL, e, &u);
 230         free(n);
 231
 232         if (r < 0)
 233                 goto fail;
 234
 235         SNAPSHOT(u)->by_snapshot_create = true;
 236         manager_dispatch_load_queue(m);
 237         assert(u->load_state == UNIT_LOADED);
 238
 239         HASHMAP_FOREACH_KEY(other, k, m->units, i) {
 240
 241                 if (other->ignore_on_snapshot)
 242                         continue;
 243
 244                 if (k != other->id)
 245                         continue;
 246
 247                 if (UNIT_VTABLE(other)->check_snapshot)
 248                         if (!UNIT_VTABLE(other)->check_snapshot(other))
 249                             continue;
 250
 251                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 252                         continue;
 253
 254                 if ((r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, other, true)) < 0)
 255                         goto fail;
 256         }
 257
 258         SNAPSHOT(u)->cleanup = cleanup;
 259         *_s = SNAPSHOT(u);
 260
 261         return 0;
 262
 263 fail:
 264         if (u)
 265                 unit_add_to_cleanup_queue(u);
 266
 267         return r;
 268 }
 269
 270 void snapshot_remove(Snapshot *s) {
 271         assert(s);
 272
 273         unit_add_to_cleanup_queue(UNIT(s));
 274 }
 275
 276 static const char* const snapshot_state_table[_SNAPSHOT_STATE_MAX] = {
 277         [SNAPSHOT_DEAD] = "dead",
 278         [SNAPSHOT_ACTIVE] = "active"
 279 };
 280
 281 DEFINE_STRING_TABLE_LOOKUP(snapshot_state, SnapshotState);
 282
 283 const UnitVTable snapshot_vtable = {
 284         .object_size = sizeof(Snapshot),
 285
 286         .no_alias = true,
 287         .no_instances = true,
 288         .no_gc = true,
 289
 290         .init = snapshot_init,
 291
 292         .load = snapshot_load,
 293         .coldplug = snapshot_coldplug,
 294
 295         .dump = snapshot_dump,
 296
 297         .start = snapshot_start,
 298         .stop = snapshot_stop,
 299
 300         .serialize = snapshot_serialize,
 301         .deserialize_item = snapshot_deserialize_item,
 302
 303         .active_state = snapshot_active_state,
 304         .sub_state_to_string = snapshot_sub_state_to_string,
 305
 306         .bus_interface = "org.freedesktop.systemd1.Snapshot",
 307         .bus_message_handler = bus_snapshot_message_handler
 308 };