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 "bus-common-errors.h"
  25 #include "dbus-snapshot.h"
  26 #include "parse-util.h"
  27 #include "parse-util.h"
  28 #include "snapshot.h"
  29 #include "string-util.h"
  30 #include "unit-name.h"
  31 #include "unit.h"
  32
  33 static const UnitActiveState state_translation_table[_SNAPSHOT_STATE_MAX] = {
  34         [SNAPSHOT_DEAD] = UNIT_INACTIVE,
  35         [SNAPSHOT_ACTIVE] = UNIT_ACTIVE
  36 };
  37
  38 static void snapshot_init(Unit *u) {
  39         Snapshot *s = SNAPSHOT(u);
  40
  41         assert(s);
  42         assert(UNIT(s)->load_state == UNIT_STUB);
  43
  44         UNIT(s)->ignore_on_isolate = true;
  45         UNIT(s)->ignore_on_snapshot = true;
  46         UNIT(s)->allow_isolate = true;
  47 }
  48
  49 static void snapshot_set_state(Snapshot *s, SnapshotState state) {
  50         SnapshotState old_state;
  51         assert(s);
  52
  53         old_state = s->state;
  54         s->state = state;
  55
  56         if (state != old_state)
  57                 log_unit_debug(UNIT(s), "Changed %s -> %s", snapshot_state_to_string(old_state), 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 1;
 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 1;
 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_unit_debug(u, "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_unit_debug(u, "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_unit_debug(u, "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, UNIT_NAME_PLAIN))
 204                         return sd_bus_error_setf(e, SD_BUS_ERROR_INVALID_ARGS, "Unit name %s is not valid.", name);
 205
 206                 if (!endswith(name, ".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                         return 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                         n = mfree(n);
 224                 }
 225         }
 226
 227         r = manager_load_unit_prepare(m, name, NULL, e, &u);
 228         if (r < 0)
 229                 goto fail;
 230
 231         u->transient = true;
 232         manager_dispatch_load_queue(m);
 233         assert(u->load_state == UNIT_LOADED);
 234
 235         HASHMAP_FOREACH_KEY(other, k, m->units, i) {
 236
 237                 if (other->ignore_on_snapshot ||
 238                     other->transient)
 239                         continue;
 240
 241                 if (k != other->id)
 242                         continue;
 243
 244                 if (UNIT_VTABLE(other)->check_snapshot)
 245                         if (!UNIT_VTABLE(other)->check_snapshot(other))
 246                             continue;
 247
 248                 if (!UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(other)))
 249                         continue;
 250
 251                 r = unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, other, true);
 252                 if (r < 0)
 253                         goto fail;
 254         }
 255
 256         SNAPSHOT(u)->cleanup = cleanup;
 257         *_s = SNAPSHOT(u);
 258
 259         log_unit_info(u, "Created snapshot.");
 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         log_unit_info(UNIT(s), "Removing snapshot.");
 274
 275         unit_add_to_cleanup_queue(UNIT(s));
 276 }
 277
 278 const UnitVTable snapshot_vtable = {
 279         .object_size = sizeof(Snapshot),
 280
 281         .no_alias = true,
 282         .no_instances = true,
 283         .no_gc = true,
 284
 285         .init = snapshot_init,
 286         .load = snapshot_load,
 287
 288         .coldplug = snapshot_coldplug,
 289
 290         .dump = snapshot_dump,
 291
 292         .start = snapshot_start,
 293         .stop = snapshot_stop,
 294
 295         .serialize = snapshot_serialize,
 296         .deserialize_item = snapshot_deserialize_item,
 297
 298         .active_state = snapshot_active_state,
 299         .sub_state_to_string = snapshot_sub_state_to_string,
 300
 301         .bus_vtable = bus_snapshot_vtable
 302 };