src/snapshot.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   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
  24 #include "unit.h"
  25 #include "snapshot.h"
  26 #include "unit-name.h"
  27 #include "dbus-snapshot.h"
  28
  29 static const UnitActiveState state_translation_table[_SNAPSHOT_STATE_MAX] = {
  30         [SNAPSHOT_DEAD] = UNIT_INACTIVE,
  31         [SNAPSHOT_ACTIVE] = UNIT_ACTIVE
  32 };
  33
  34 static void snapshot_set_state(Snapshot *s, SnapshotState state) {
  35         SnapshotState old_state;
  36         assert(s);
  37
  38         old_state = s->state;
  39         s->state = state;
  40
  41         if (state != old_state)
  42                 log_debug("%s changed %s -> %s",
  43                           s->meta.id,
  44                           snapshot_state_to_string(old_state),
  45                           snapshot_state_to_string(state));
  46
  47         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state]);
  48 }
  49
  50 static int snapshot_load(Unit *u) {
  51         Snapshot *s = SNAPSHOT(u);
  52
  53         assert(u);
  54         assert(u->meta.load_state == UNIT_STUB);
  55
  56         /* Make sure that only snapshots created via snapshot_create()
  57          * can be loaded */
  58         if (!s->by_snapshot_create)
  59                 return -ENOENT;
  60
  61         u->meta.load_state = UNIT_LOADED;
  62         return 0;
  63 }
  64
  65 static int snapshot_coldplug(Unit *u) {
  66         Snapshot *s = SNAPSHOT(u);
  67
  68         assert(s);
  69         assert(s->state == SNAPSHOT_DEAD);
  70
  71         if (s->deserialized_state != s->state)
  72                 snapshot_set_state(s, s->deserialized_state);
  73
  74         return 0;
  75 }
  76
  77 static void snapshot_dump(Unit *u, FILE *f, const char *prefix) {
  78         Snapshot *s = SNAPSHOT(u);
  79
  80         assert(s);
  81         assert(f);
  82
  83         fprintf(f,
  84                 "%sSnapshot State: %s\n"
  85                 "%sClean Up: %s\n",
  86                 prefix, snapshot_state_to_string(s->state),
  87                 prefix, yes_no(s->cleanup));
  88 }
  89
  90 static int snapshot_start(Unit *u) {
  91         Snapshot *s = SNAPSHOT(u);
  92
  93         assert(s);
  94         assert(s->state == SNAPSHOT_DEAD);
  95
  96         snapshot_set_state(s, SNAPSHOT_ACTIVE);
  97
  98         if (s->cleanup)
  99                 unit_add_to_cleanup_queue(u);
 100
 101         return 0;
 102 }
 103
 104 static int snapshot_stop(Unit *u) {
 105         Snapshot *s = SNAPSHOT(u);
 106
 107         assert(s);
 108         assert(s->state == SNAPSHOT_ACTIVE);
 109
 110         snapshot_set_state(s, SNAPSHOT_DEAD);
 111         return 0;
 112 }
 113
 114 static int snapshot_serialize(Unit *u, FILE *f, FDSet *fds) {
 115         Snapshot *s = SNAPSHOT(u);
 116         Unit *other;
 117         Iterator i;
 118
 119         assert(s);
 120         assert(f);
 121         assert(fds);
 122
 123         unit_serialize_item(u, f, "state", snapshot_state_to_string(s->state));
 124         unit_serialize_item(u, f, "cleanup", yes_no(s->cleanup));
 125         SET_FOREACH(other, u->meta.dependencies[UNIT_WANTS], i)
 126                 unit_serialize_item(u, f, "wants", other->meta.id);
 127
 128         return 0;
 129 }
 130
 131 static int snapshot_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 132         Snapshot *s = SNAPSHOT(u);
 133         int r;
 134
 135         assert(u);
 136         assert(key);
 137         assert(value);
 138         assert(fds);
 139
 140         if (streq(key, "state")) {
 141                 SnapshotState state;
 142
 143                 if ((state = snapshot_state_from_string(value)) < 0)
 144                         log_debug("Failed to parse state value %s", value);
 145                 else
 146                         s->deserialized_state = state;
 147
 148         } else if (streq(key, "cleanup")) {
 149
 150                 if ((r = parse_boolean(value)) < 0)
 151                         log_debug("Failed to parse cleanup value %s", value);
 152                 else
 153                         s->cleanup = r;
 154
 155         } else if (streq(key, "wants")) {
 156
 157                 if ((r = unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_WANTS, value, NULL, true)) < 0)
 158                         return r;
 159         } else
 160                 log_debug("Unknown serialization key '%s'", key);
 161
 162         return 0;
 163 }
 164
 165 static UnitActiveState snapshot_active_state(Unit *u) {
 166         assert(u);
 167
 168         return state_translation_table[SNAPSHOT(u)->state];
 169 }
 170
 171 static const char *snapshot_sub_state_to_string(Unit *u) {
 172         assert(u);
 173
 174         return snapshot_state_to_string(SNAPSHOT(u)->state);
 175 }
 176
 177 int snapshot_create(Manager *m, const char *name, bool cleanup, Snapshot **_s) {
 178         Iterator i;
 179         Unit *other, *u = NULL;
 180         char *n = NULL;
 181         int r;
 182         const char *k;
 183
 184         assert(m);
 185         assert(_s);
 186
 187         if (name) {
 188                 if (!unit_name_is_valid(name))
 189                         return -EINVAL;
 190
 191                 if (unit_name_to_type(name) != UNIT_SNAPSHOT)
 192                         return -EINVAL;
 193
 194                 if (manager_get_unit(m, name))
 195                         return -EEXIST;
 196
 197         } else {
 198
 199                 for (;;) {
 200                         if (asprintf(&n, "snapshot-%u.snapshot", ++ m->n_snapshots) < 0)
 201                                 return -ENOMEM;
 202
 203                         if (!manager_get_unit(m, n))
 204                                 break;
 205
 206                         free(n);
 207                 }
 208
 209                 name = n;
 210         }
 211
 212         r = manager_load_unit_prepare(m, name, NULL, &u);
 213         free(n);
 214
 215         if (r < 0)
 216                 goto fail;
 217
 218         SNAPSHOT(u)->by_snapshot_create = true;
 219         manager_dispatch_load_queue(m);
 220         assert(u->meta.load_state == UNIT_LOADED);
 221
 222         HASHMAP_FOREACH_KEY(other, k, m->units, i) {
 223
 224                 if (UNIT_VTABLE(other)->no_snapshots)
 225                         continue;
 226
 227                 if (k != other->meta.id)
 228                         continue;
 229
 230                 if (UNIT_VTABLE(other)->check_snapshot)
 231                         if (!UNIT_VTABLE(other)->check_snapshot(other))
 232                             continue;
 233
 234                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 235                         continue;
 236
 237                 if ((r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, other, true)) < 0)
 238                         goto fail;
 239         }
 240
 241         SNAPSHOT(u)->cleanup = cleanup;
 242         *_s = SNAPSHOT(u);
 243
 244         return 0;
 245
 246 fail:
 247         if (u)
 248                 unit_add_to_cleanup_queue(u);
 249
 250         return r;
 251 }
 252
 253 void snapshot_remove(Snapshot *s) {
 254         assert(s);
 255
 256         unit_add_to_cleanup_queue(UNIT(s));
 257 }
 258
 259 static const char* const snapshot_state_table[_SNAPSHOT_STATE_MAX] = {
 260         [SNAPSHOT_DEAD] = "dead",
 261         [SNAPSHOT_ACTIVE] = "active"
 262 };
 263
 264 DEFINE_STRING_TABLE_LOOKUP(snapshot_state, SnapshotState);
 265
 266 const UnitVTable snapshot_vtable = {
 267         .suffix = ".snapshot",
 268
 269         .no_alias = true,
 270         .no_instances = true,
 271         .no_snapshots = true,
 272         .no_gc = true,
 273
 274         .load = snapshot_load,
 275         .coldplug = snapshot_coldplug,
 276
 277         .dump = snapshot_dump,
 278
 279         .start = snapshot_start,
 280         .stop = snapshot_stop,
 281
 282         .serialize = snapshot_serialize,
 283         .deserialize_item = snapshot_deserialize_item,
 284
 285         .active_state = snapshot_active_state,
 286         .sub_state_to_string = snapshot_sub_state_to_string,
 287
 288         .bus_message_handler = bus_snapshot_message_handler
 289 };