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         UNIT(s)->allow_isolate = true;
  44 }
  45
  46 static void snapshot_set_state(Snapshot *s, SnapshotState state) {
  47         SnapshotState old_state;
  48         assert(s);
  49
  50         old_state = s->state;
  51         s->state = state;
  52
  53         if (state != old_state)
  54                 log_debug("%s changed %s -> %s",
  55                           UNIT(s)->id,
  56                           snapshot_state_to_string(old_state),
  57                           snapshot_state_to_string(state));
  58
  59         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], true);
  60 }
  61
  62 static int snapshot_load(Unit *u) {
  63         Snapshot *s = SNAPSHOT(u);
  64
  65         assert(u);
  66         assert(u->load_state == UNIT_STUB);
  67
  68         /* Make sure that only snapshots created via snapshot_create()
  69          * can be loaded */
  70         if (!u->transient && UNIT(s)->manager->n_reloading <= 0)
  71                 return -ENOENT;
  72
  73         u->load_state = UNIT_LOADED;
  74         return 0;
  75 }
  76
  77 static int snapshot_coldplug(Unit *u) {
  78         Snapshot *s = SNAPSHOT(u);
  79
  80         assert(s);
  81         assert(s->state == SNAPSHOT_DEAD);
  82
  83         if (s->deserialized_state != s->state)
  84                 snapshot_set_state(s, s->deserialized_state);
  85
  86         return 0;
  87 }
  88
  89 static void snapshot_dump(Unit *u, FILE *f, const char *prefix) {
  90         Snapshot *s = SNAPSHOT(u);
  91
  92         assert(s);
  93         assert(f);
  94
  95         fprintf(f,
  96                 "%sSnapshot State: %s\n"
  97                 "%sClean Up: %s\n",
  98                 prefix, snapshot_state_to_string(s->state),
  99                 prefix, yes_no(s->cleanup));
 100 }
 101
 102 static int snapshot_start(Unit *u) {
 103         Snapshot *s = SNAPSHOT(u);
 104
 105         assert(s);
 106         assert(s->state == SNAPSHOT_DEAD);
 107
 108         snapshot_set_state(s, SNAPSHOT_ACTIVE);
 109
 110         if (s->cleanup)
 111                 unit_add_to_cleanup_queue(u);
 112
 113         return 0;
 114 }
 115
 116 static int snapshot_stop(Unit *u) {
 117         Snapshot *s = SNAPSHOT(u);
 118
 119         assert(s);
 120         assert(s->state == SNAPSHOT_ACTIVE);
 121
 122         snapshot_set_state(s, SNAPSHOT_DEAD);
 123         return 0;
 124 }
 125
 126 static int snapshot_serialize(Unit *u, FILE *f, FDSet *fds) {
 127         Snapshot *s = SNAPSHOT(u);
 128         Unit *other;
 129         Iterator i;
 130
 131         assert(s);
 132         assert(f);
 133         assert(fds);
 134
 135         unit_serialize_item(u, f, "state", snapshot_state_to_string(s->state));
 136         unit_serialize_item(u, f, "cleanup", yes_no(s->cleanup));
 137         SET_FOREACH(other, u->dependencies[UNIT_WANTS], i)
 138                 unit_serialize_item(u, f, "wants", other->id);
 139
 140         return 0;
 141 }
 142
 143 static int snapshot_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 144         Snapshot *s = SNAPSHOT(u);
 145         int r;
 146
 147         assert(u);
 148         assert(key);
 149         assert(value);
 150         assert(fds);
 151
 152         if (streq(key, "state")) {
 153                 SnapshotState state;
 154
 155                 state = snapshot_state_from_string(value);
 156                 if (state < 0)
 157                         log_debug("Failed to parse state value %s", value);
 158                 else
 159                         s->deserialized_state = state;
 160
 161         } else if (streq(key, "cleanup")) {
 162
 163                 r = parse_boolean(value);
 164                 if (r < 0)
 165                         log_debug("Failed to parse cleanup value %s", value);
 166                 else
 167                         s->cleanup = r;
 168
 169         } else if (streq(key, "wants")) {
 170
 171                 r = unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_WANTS, value, NULL, true);
 172                 if (r < 0)
 173                         return r;
 174         } else
 175                 log_debug("Unknown serialization key '%s'", key);
 176
 177         return 0;
 178 }
 179
 180 _pure_ static UnitActiveState snapshot_active_state(Unit *u) {
 181         assert(u);
 182
 183         return state_translation_table[SNAPSHOT(u)->state];
 184 }
 185
 186 _pure_ static const char *snapshot_sub_state_to_string(Unit *u) {
 187         assert(u);
 188
 189         return snapshot_state_to_string(SNAPSHOT(u)->state);
 190 }
 191
 192 int snapshot_create(Manager *m, const char *name, bool cleanup, DBusError *e, Snapshot **_s) {
 193         _cleanup_free_ char *n = NULL;
 194         Unit *other, *u = NULL;
 195         Iterator i;
 196         int r;
 197         const char *k;
 198
 199         assert(m);
 200         assert(_s);
 201
 202         if (name) {
 203                 if (!unit_name_is_valid(name, false)) {
 204                         dbus_set_error(e, BUS_ERROR_INVALID_NAME, "Unit name %s is not valid.", name);
 205                         return -EINVAL;
 206                 }
 207
 208                 if (unit_name_to_type(name) != UNIT_SNAPSHOT) {
 209                         dbus_set_error(e, BUS_ERROR_UNIT_TYPE_MISMATCH, "Unit name %s lacks snapshot suffix.", name);
 210                         return -EINVAL;
 211                 }
 212
 213                 if (manager_get_unit(m, name)) {
 214                         dbus_set_error(e, BUS_ERROR_UNIT_EXISTS, "Snapshot %s exists already.", name);
 215                         return -EEXIST;
 216                 }
 217
 218         } else {
 219
 220                 for (;;) {
 221                         if (asprintf(&n, "snapshot-%u.snapshot", ++ m->n_snapshots) < 0)
 222                                 return -ENOMEM;
 223
 224                         if (!manager_get_unit(m, n))
 225                                 break;
 226
 227                         free(n);
 228                         n = NULL;
 229                 }
 230         }
 231
 232         r = manager_load_unit_prepare(m, name, NULL, e, &u);
 233         if (r < 0)
 234                 goto fail;
 235
 236         u->transient = true;
 237         manager_dispatch_load_queue(m);
 238         assert(u->load_state == UNIT_LOADED);
 239
 240         HASHMAP_FOREACH_KEY(other, k, m->units, i) {
 241
 242                 if (other->ignore_on_snapshot ||
 243                     other->transient)
 244                         continue;
 245
 246                 if (k != other->id)
 247                         continue;
 248
 249                 if (UNIT_VTABLE(other)->check_snapshot)
 250                         if (!UNIT_VTABLE(other)->check_snapshot(other))
 251                             continue;
 252
 253                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 254                         continue;
 255
 256                 r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, other, true);
 257                 if (r < 0)
 258                         goto fail;
 259         }
 260
 261         SNAPSHOT(u)->cleanup = cleanup;
 262         *_s = SNAPSHOT(u);
 263
 264         return 0;
 265
 266 fail:
 267         if (u)
 268                 unit_add_to_cleanup_queue(u);
 269
 270         return r;
 271 }
 272
 273 void snapshot_remove(Snapshot *s) {
 274         assert(s);
 275
 276         unit_add_to_cleanup_queue(UNIT(s));
 277 }
 278
 279 static const char* const snapshot_state_table[_SNAPSHOT_STATE_MAX] = {
 280         [SNAPSHOT_DEAD] = "dead",
 281         [SNAPSHOT_ACTIVE] = "active"
 282 };
 283
 284 DEFINE_STRING_TABLE_LOOKUP(snapshot_state, SnapshotState);
 285
 286 const UnitVTable snapshot_vtable = {
 287         .object_size = sizeof(Snapshot),
 288
 289         .no_alias = true,
 290         .no_instances = true,
 291         .no_gc = true,
 292
 293         .init = snapshot_init,
 294
 295         .load = snapshot_load,
 296         .coldplug = snapshot_coldplug,
 297
 298         .dump = snapshot_dump,
 299
 300         .start = snapshot_start,
 301         .stop = snapshot_stop,
 302
 303         .serialize = snapshot_serialize,
 304         .deserialize_item = snapshot_deserialize_item,
 305
 306         .active_state = snapshot_active_state,
 307         .sub_state_to_string = snapshot_sub_state_to_string,
 308
 309         .bus_interface = "org.freedesktop.systemd1.Snapshot",
 310         .bus_message_handler = bus_snapshot_message_handler
 311 };