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, sd_bus_error *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, TEMPLATE_INVALID))
 204                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s is not valid.", name);
 205
 206                 if (unit_name_to_type(name) != UNIT_SNAPSHOT)
 207                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s lacks snapshot suffix.", name);
 208
 209                 if (manager_get_unit(m, name))
 210                         sd_bus_error_setf(e, BUS_ERROR_UNIT_EXISTS, "Snapshot %s exists already.", name);
 211
 212         } else {
 213
 214                 for (;;) {
 215                         if (asprintf(&n, "snapshot-%u.snapshot", ++ m->n_snapshots) < 0)
 216                                 return -ENOMEM;
 217
 218                         if (!manager_get_unit(m, n)) {
 219                                 name = n;
 220                                 break;
 221                         }
 222
 223                         free(n);
 224                         n = NULL;
 225                 }
 226         }
 227
 228         r = manager_load_unit_prepare(m, name, NULL, e, &u);
 229         if (r < 0)
 230                 goto fail;
 231
 232         u->transient = true;
 233         manager_dispatch_load_queue(m);
 234         assert(u->load_state == UNIT_LOADED);
 235
 236         HASHMAP_FOREACH_KEY(other, k, m->units, i) {
 237
 238                 if (other->ignore_on_snapshot ||
 239                     other->transient)
 240                         continue;
 241
 242                 if (k != other->id)
 243                         continue;
 244
 245                 if (UNIT_VTABLE(other)->check_snapshot)
 246                         if (!UNIT_VTABLE(other)->check_snapshot(other))
 247                             continue;
 248
 249                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 250                         continue;
 251
 252                 r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, other, true);
 253                 if (r < 0)
 254                         goto fail;
 255         }
 256
 257         SNAPSHOT(u)->cleanup = cleanup;
 258         *_s = SNAPSHOT(u);
 259
 260         return 0;
 261
 262 fail:
 263         if (u)
 264                 unit_add_to_cleanup_queue(u);
 265
 266         return r;
 267 }
 268
 269 void snapshot_remove(Snapshot *s) {
 270         assert(s);
 271
 272         unit_add_to_cleanup_queue(UNIT(s));
 273 }
 274
 275 static const char* const snapshot_state_table[_SNAPSHOT_STATE_MAX] = {
 276         [SNAPSHOT_DEAD] = "dead",
 277         [SNAPSHOT_ACTIVE] = "active"
 278 };
 279
 280 DEFINE_STRING_TABLE_LOOKUP(snapshot_state, SnapshotState);
 281
 282 const UnitVTable snapshot_vtable = {
 283         .object_size = sizeof(Snapshot),
 284
 285         .no_alias = true,
 286         .no_instances = true,
 287         .no_gc = true,
 288
 289         .init = snapshot_init,
 290         .load = snapshot_load,
 291
 292         .coldplug = snapshot_coldplug,
 293
 294         .dump = snapshot_dump,
 295
 296         .start = snapshot_start,
 297         .stop = snapshot_stop,
 298
 299         .serialize = snapshot_serialize,
 300         .deserialize_item = snapshot_deserialize_item,
 301
 302         .active_state = snapshot_active_state,
 303         .sub_state_to_string = snapshot_sub_state_to_string,
 304
 305         .bus_interface = "org.freedesktop.systemd1.Snapshot",
 306         .bus_vtable = bus_snapshot_vtable
 307 };