swap.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 #include <limits.h>
  24 #include <unistd.h>
  25 #include <fcntl.h>
  26 #include <sys/epoll.h>
  27 #include <sys/stat.h>
  28 #include <sys/swap.h>
  29
  30 #include "unit.h"
  31 #include "swap.h"
  32 #include "load-fragment.h"
  33 #include "load-dropin.h"
  34 #include "unit-name.h"
  35 #include "dbus-swap.h"
  36
  37 static const UnitActiveState state_translation_table[_SWAP_STATE_MAX] = {
  38         [SWAP_DEAD] = UNIT_INACTIVE,
  39         [SWAP_ACTIVE] = UNIT_ACTIVE,
  40         [SWAP_MAINTAINANCE] = UNIT_INACTIVE
  41 };
  42
  43 static void swap_done(Unit *u) {
  44         Swap *s = SWAP(u);
  45
  46         assert(s);
  47
  48         free(s->what);
  49 }
  50
  51 static int swap_verify(Swap *s) {
  52         bool b;
  53         char *e;
  54
  55         if (UNIT(s)->meta.load_state != UNIT_LOADED)
  56                   return 0;
  57
  58         if (!(e = unit_name_from_path(s->what, ".swap")))
  59                   return -ENOMEM;
  60
  61         b = unit_has_name(UNIT(s), e);
  62         free(e);
  63
  64         if (!b) {
  65                 log_error("%s: Value of \"What\" and unit name do not match, not loading.\n", UNIT(s)->meta.id);
  66                 return -EINVAL;
  67         }
  68         return 0;
  69 }
  70
  71 int swap_add_one_mount_link(Swap *s, Mount *m) {
  72          int r;
  73
  74         assert(s);
  75         assert(m);
  76
  77         if (s->meta.load_state != UNIT_LOADED ||
  78             m->meta.load_state != UNIT_LOADED)
  79                 return 0;
  80
  81         if (!path_startswith(s->what, m->where))
  82                 return 0;
  83
  84         if ((r = unit_add_dependency(UNIT(m), UNIT_BEFORE, UNIT(s), true)) < 0)
  85                 return r;
  86
  87         if ((r = unit_add_dependency(UNIT(s), UNIT_REQUIRES, UNIT(m), true)) < 0)
  88                 return r;
  89
  90         return 0;
  91 }
  92
  93 static int swap_add_mount_links(Swap *s) {
  94         Meta *other;
  95         int r;
  96
  97         assert(s);
  98
  99         LIST_FOREACH(units_per_type, other, s->meta.manager->units_per_type[UNIT_MOUNT])
 100                 if ((r = swap_add_one_mount_link(s, (Mount*) other)) < 0)
 101                         return r;
 102
 103         return 0;
 104 }
 105
 106 static int swap_add_target_links(Swap *s) {
 107         Manager *m = s->meta.manager;
 108         Unit *tu;
 109         int r;
 110
 111         if ((r = manager_load_unit(m, SPECIAL_SWAP_TARGET, NULL, &tu)) < 0)
 112                 return r;
 113
 114         if (!s->no_auto)
 115                 if ((r = unit_add_dependency(tu, UNIT_WANTS, UNIT(s), true)) < 0)
 116                         return r;
 117
 118         return unit_add_dependency(UNIT(s), UNIT_BEFORE, tu, true);
 119 }
 120
 121 static int swap_load(Unit *u) {
 122         int r;
 123         Swap *s = SWAP(u);
 124
 125         assert(s);
 126         assert(u->meta.load_state == UNIT_STUB);
 127
 128         /* Load a .swap file */
 129         if ((r = unit_load_fragment_and_dropin_optional(u)) < 0)
 130                 return r;
 131
 132         if (u->meta.load_state == UNIT_LOADED) {
 133                 if (!s->what)
 134                         if (!(s->what = unit_name_to_path(u->meta.id)))
 135                                 return -ENOMEM;
 136
 137                 path_kill_slashes(s->what);
 138
 139                 if ((r = unit_add_node_link(u, s->what,
 140                                             (u->meta.manager->running_as == MANAGER_INIT ||
 141                                              u->meta.manager->running_as == MANAGER_SYSTEM))) < 0)
 142                         return r;
 143
 144                 if ((r = swap_add_mount_links(s)) < 0)
 145                         return r;
 146
 147                 if ((r = swap_add_target_links(s)) < 0)
 148                         return r;
 149         }
 150
 151         return swap_verify(s);
 152 }
 153
 154 int swap_add_one(Manager *m, const char *what, bool no_auto, int prio, bool from_proc_swaps) {
 155         Unit *u;
 156         char *e;
 157         bool delete;
 158         int r;
 159
 160         if (!(e = unit_name_from_path(what, ".swap")))
 161                 return -ENOMEM;
 162
 163         if (!(u = manager_get_unit(m, e))) {
 164                 delete = true;
 165
 166                 if (!(u = unit_new(m))) {
 167                         free(e);
 168                         return -ENOMEM;
 169                 }
 170
 171                 r = unit_add_name(u, e);
 172                 free(e);
 173
 174                 if (r < 0)
 175                         goto fail;
 176
 177                 if (!(SWAP(u)->what = strdup(what))) {
 178                         r = -ENOMEM;
 179                         goto fail;
 180                 }
 181
 182                 if ((r = unit_set_description(u, what)) < 0)
 183                         goto fail;
 184
 185                 unit_add_to_load_queue(u);
 186
 187                 SWAP(u)->from_proc_swaps_only = from_proc_swaps;
 188         } else {
 189                 if (SWAP(u)->from_proc_swaps_only && !from_proc_swaps)
 190                         SWAP(u)->from_proc_swaps_only = false;
 191
 192                 delete = false;
 193                 free(e);
 194         }
 195
 196         if (!from_proc_swaps)
 197                 SWAP(u)->no_auto = no_auto;
 198         else
 199                 SWAP(u)->found_in_proc_swaps = true;
 200
 201         SWAP(u)->priority = prio;
 202
 203         return 0;
 204
 205 fail:
 206         if (delete)
 207                 unit_free(u);
 208
 209         return 0;
 210 }
 211
 212 static void swap_set_state(Swap *s, SwapState state) {
 213         SwapState old_state;
 214         assert(s);
 215
 216         old_state = s->state;
 217         s->state = state;
 218
 219         if (state != old_state)
 220                 log_debug("%s changed %s -> %s",
 221                           UNIT(s)->meta.id,
 222                           swap_state_to_string(old_state),
 223                           swap_state_to_string(state));
 224
 225         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state]);
 226 }
 227
 228 static int swap_coldplug(Unit *u) {
 229         Swap *s = SWAP(u);
 230         SwapState new_state = SWAP_DEAD;
 231
 232         assert(s);
 233         assert(s->state == SWAP_DEAD);
 234
 235         if (s->deserialized_state != s->state)
 236                 new_state = s->deserialized_state;
 237         else if (s->found_in_proc_swaps)
 238                 new_state = SWAP_ACTIVE;
 239
 240         if (new_state != s->state)
 241                 swap_set_state(s, s->deserialized_state);
 242
 243         return 0;
 244 }
 245
 246 static void swap_dump(Unit *u, FILE *f, const char *prefix) {
 247         Swap *s = SWAP(u);
 248
 249         assert(s);
 250
 251         fprintf(f,
 252                 "%sAutomount State: %s\n"
 253                 "%sWhat: %s\n"
 254                 "%sPriority: %i\n"
 255                 "%sNoAuto: %s\n",
 256                 prefix, swap_state_to_string(s->state),
 257                 prefix, s->what,
 258                 prefix, s->priority,
 259                 prefix, yes_no(s->no_auto));
 260 }
 261
 262 static void swap_enter_dead(Swap *s, bool success) {
 263         assert(s);
 264
 265         swap_set_state(s, success ? SWAP_MAINTAINANCE : SWAP_DEAD);
 266 }
 267
 268 static int swap_start(Unit *u) {
 269         Swap *s = SWAP(u);
 270         int r;
 271
 272         assert(s);
 273
 274         assert(s->state == SWAP_DEAD || s->state == SWAP_MAINTAINANCE);
 275
 276         r = swapon(s->what, (s->priority << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK);
 277
 278         if (r < 0 && errno != EBUSY) {
 279                 r = -errno;
 280                 swap_enter_dead(s, false);
 281                 return r;
 282         }
 283
 284         swap_set_state(s, SWAP_ACTIVE);
 285         return 0;
 286 }
 287
 288 static int swap_stop(Unit *u) {
 289         Swap *s = SWAP(u);
 290         int r;
 291
 292         assert(s);
 293
 294         assert(s->state == SWAP_ACTIVE);
 295
 296         r = swapoff(s->what);
 297         swap_enter_dead(s, r >= 0 || errno == EINVAL);
 298
 299         return 0;
 300 }
 301
 302 static int swap_serialize(Unit *u, FILE *f, FDSet *fds) {
 303         Swap *s = SWAP(u);
 304
 305         assert(s);
 306         assert(f);
 307         assert(fds);
 308
 309         unit_serialize_item(u, f, "state", swap_state_to_string(s->state));
 310
 311         return 0;
 312 }
 313
 314 static int swap_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 315         Swap *s = SWAP(u);
 316
 317         assert(s);
 318         assert(fds);
 319
 320         if (streq(key, "state")) {
 321                 SwapState state;
 322
 323                 if ((state = swap_state_from_string(value)) < 0)
 324                         log_debug("Failed to parse state value %s", value);
 325                 else
 326                         s->deserialized_state = state;
 327         } else
 328                 log_debug("Unknown serialization key '%s'", key);
 329
 330         return 0;
 331 }
 332
 333 static UnitActiveState swap_active_state(Unit *u) {
 334         assert(u);
 335
 336         return state_translation_table[SWAP(u)->state];
 337 }
 338
 339 static const char *swap_sub_state_to_string(Unit *u) {
 340         assert(u);
 341
 342         return swap_state_to_string(SWAP(u)->state);
 343 }
 344
 345 static bool swap_check_gc(Unit *u) {
 346         Swap *s = SWAP(u);
 347
 348         assert(s);
 349
 350         return !s->from_proc_swaps_only || s->found_in_proc_swaps;
 351 }
 352
 353 static int swap_load_proc_swaps(Manager *m) {
 354         Meta *meta;
 355
 356         rewind(m->proc_swaps);
 357
 358         (void) fscanf(m->proc_self_mountinfo, "%*s %*s %*s %*s %*s\n");
 359
 360         for (;;) {
 361                 char *dev = NULL, *d;
 362                 int prio = 0, k;
 363
 364                 k = fscanf(m->proc_self_mountinfo,
 365                            "%ms " /* device/file */
 366                            "%*s " /* type of swap */
 367                            "%*s " /* swap size */
 368                            "%*s " /* used */
 369                            "%d\n", /* priority */
 370                            &dev, &prio);
 371
 372                 if (k != 2) {
 373                         if (k == EOF)
 374                                 k = 0;
 375
 376                         free(dev);
 377                         return -EBADMSG;
 378                 }
 379                 if (!(d = cunescape(dev))) {
 380                         free(dev);
 381                         k = -ENOMEM;
 382                         return k;
 383                 }
 384
 385                 k = swap_add_one(m, d, false, prio, true);
 386                 free(dev);
 387                 free(d);
 388
 389                 if (k < 0)
 390                         return k;
 391         }
 392
 393         LIST_FOREACH(units_per_type, meta, m->units_per_type[UNIT_SWAP]) {
 394                 Swap *s = (Swap*) meta;
 395
 396                 if (s->state != SWAP_DEAD && s->state != SWAP_ACTIVE)
 397                         continue;
 398
 399                 if ((s->state == SWAP_DEAD && !s->found_in_proc_swaps) ||
 400                     (s->state == SWAP_ACTIVE && s->found_in_proc_swaps))
 401                         continue;
 402
 403                 swap_set_state(s, s->found_in_proc_swaps ? SWAP_ACTIVE : SWAP_DEAD);
 404
 405                 /* Reset the flags for later calls */
 406                 s->found_in_proc_swaps = false;
 407         }
 408 }
 409
 410 static void swap_shutdown(Manager *m) {
 411         assert(m);
 412
 413         if (m->proc_swaps) {
 414                 fclose(m->proc_swaps);
 415                 m->proc_swaps = NULL;
 416         }
 417 }
 418
 419 static const char* const swap_state_table[_SWAP_STATE_MAX] = {
 420         [SWAP_DEAD] = "dead",
 421         [SWAP_ACTIVE] = "active",
 422         [SWAP_MAINTAINANCE] = "maintainance"
 423 };
 424
 425 DEFINE_STRING_TABLE_LOOKUP(swap_state, SwapState);
 426
 427 static int swap_enumerate(Manager *m) {
 428         int r;
 429         assert(m);
 430
 431         if (!m->proc_swaps &&
 432             !(m->proc_swaps = fopen("/proc/swaps", "er")))
 433                 return -errno;
 434
 435         if ((r = swap_load_proc_swaps(m)) < 0)
 436                 swap_shutdown(m);
 437
 438         return r;
 439 }
 440
 441 const UnitVTable swap_vtable = {
 442         .suffix = ".swap",
 443
 444         .no_alias = true,
 445         .no_instances = true,
 446         .no_isolate = true,
 447
 448         .load = swap_load,
 449         .done = swap_done,
 450
 451         .coldplug = swap_coldplug,
 452
 453         .dump = swap_dump,
 454
 455         .start = swap_start,
 456         .stop = swap_stop,
 457
 458         .serialize = swap_serialize,
 459         .deserialize_item = swap_deserialize_item,
 460
 461         .active_state = swap_active_state,
 462         .sub_state_to_string = swap_sub_state_to_string,
 463
 464         .check_gc = swap_check_gc,
 465
 466         .bus_message_handler = bus_swap_message_handler,
 467
 468         .enumerate = swap_enumerate,
 469         .shutdown = swap_shutdown
 470 };