src/swap.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 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 #include "special.h"
  37
  38 static const UnitActiveState state_translation_table[_SWAP_STATE_MAX] = {
  39         [SWAP_DEAD] = UNIT_INACTIVE,
  40         [SWAP_ACTIVE] = UNIT_ACTIVE,
  41         [SWAP_FAILED] = UNIT_FAILED
  42 };
  43
  44 static void swap_init(Unit *u) {
  45         Swap *s = SWAP(u);
  46
  47         assert(s);
  48         assert(s->meta.load_state == UNIT_STUB);
  49
  50         s->parameters_etc_fstab.priority = s->parameters_proc_swaps.priority = s->parameters_fragment.priority = -1;
  51 }
  52
  53 static void swap_done(Unit *u) {
  54         Swap *s = SWAP(u);
  55
  56         assert(s);
  57
  58         free(s->what);
  59         free(s->parameters_etc_fstab.what);
  60         free(s->parameters_proc_swaps.what);
  61         free(s->parameters_fragment.what);
  62 }
  63
  64 int swap_add_one_mount_link(Swap *s, Mount *m) {
  65          int r;
  66
  67         assert(s);
  68         assert(m);
  69
  70         if (s->meta.load_state != UNIT_LOADED ||
  71             m->meta.load_state != UNIT_LOADED)
  72                 return 0;
  73
  74         if (is_device_path(s->what))
  75                 return 0;
  76
  77         if (!path_startswith(s->what, m->where))
  78                 return 0;
  79
  80         if ((r = unit_add_two_dependencies(UNIT(s), UNIT_AFTER, UNIT_REQUIRES, UNIT(m), true)) < 0)
  81                 return r;
  82
  83         return 0;
  84 }
  85
  86 static int swap_add_mount_links(Swap *s) {
  87         Meta *other;
  88         int r;
  89
  90         assert(s);
  91
  92         LIST_FOREACH(units_per_type, other, s->meta.manager->units_per_type[UNIT_MOUNT])
  93                 if ((r = swap_add_one_mount_link(s, (Mount*) other)) < 0)
  94                         return r;
  95
  96         return 0;
  97 }
  98
  99 static int swap_add_target_links(Swap *s) {
 100         Unit *tu;
 101         SwapParameters *p;
 102         int r;
 103
 104         assert(s);
 105
 106         if (s->from_fragment)
 107                 p = &s->parameters_fragment;
 108         else if (s->from_etc_fstab)
 109                 p = &s->parameters_etc_fstab;
 110         else
 111                 return 0;
 112
 113         if ((r = manager_load_unit(s->meta.manager, SPECIAL_SWAP_TARGET, NULL, NULL, &tu)) < 0)
 114                 return r;
 115
 116         if (!p->noauto &&
 117             (p->handle || s->meta.manager->swap_auto) &&
 118             !s->from_fragment &&
 119             s->meta.manager->running_as == MANAGER_SYSTEM)
 120                 if ((r = unit_add_dependency(tu, UNIT_WANTS, UNIT(s), true)) < 0)
 121                         return r;
 122
 123         return unit_add_dependency(UNIT(s), UNIT_BEFORE, tu, true);
 124 }
 125
 126 static int swap_add_device_links(Swap *s) {
 127         SwapParameters *p;
 128
 129         assert(s);
 130
 131         if (!s->what)
 132                 return 0;
 133
 134         if (s->from_fragment)
 135                 p = &s->parameters_fragment;
 136         else if (s->from_etc_fstab)
 137                 p = &s->parameters_etc_fstab;
 138         else
 139                 return 0;
 140
 141         return unit_add_node_link(UNIT(s), s->what,
 142                                   !p->noauto && p->nofail &&
 143                                   s->meta.manager->running_as == MANAGER_SYSTEM);
 144 }
 145
 146 static int swap_add_default_dependencies(Swap *s) {
 147         int r;
 148
 149         assert(s);
 150
 151         if (s->meta.manager->running_as == MANAGER_SYSTEM) {
 152
 153                 if ((r = unit_add_dependency_by_name(UNIT(s), UNIT_AFTER, SPECIAL_SYSINIT_TARGET, NULL, true)) < 0)
 154                         return r;
 155
 156                 /* Note that by default we don't disable swap devices
 157                  * on shutdown. i.e. there is no umount.target
 158                  * conflicts here. */
 159         }
 160
 161         return 0;
 162 }
 163
 164 static int swap_verify(Swap *s) {
 165         bool b;
 166         char *e;
 167
 168         if (s->meta.load_state != UNIT_LOADED)
 169                   return 0;
 170
 171         if (!(e = unit_name_from_path(s->what, ".swap")))
 172                   return -ENOMEM;
 173
 174         b = unit_has_name(UNIT(s), e);
 175         free(e);
 176
 177         if (!b) {
 178                 log_error("%s: Value of \"What\" and unit name do not match, not loading.\n", s->meta.id);
 179                 return -EINVAL;
 180         }
 181
 182         return 0;
 183 }
 184
 185 static int swap_load(Unit *u) {
 186         int r;
 187         Swap *s = SWAP(u);
 188
 189         assert(s);
 190         assert(u->meta.load_state == UNIT_STUB);
 191
 192         /* Load a .swap file */
 193         if ((r = unit_load_fragment_and_dropin_optional(u)) < 0)
 194                 return r;
 195
 196         if (u->meta.load_state == UNIT_LOADED) {
 197
 198                 if (s->meta.fragment_path)
 199                         s->from_fragment = true;
 200
 201                 if (!s->what) {
 202                         if (s->parameters_fragment.what)
 203                                 s->what = strdup(s->parameters_fragment.what);
 204                         else if (s->parameters_etc_fstab.what)
 205                                 s->what = strdup(s->parameters_etc_fstab.what);
 206                         else if (s->parameters_proc_swaps.what)
 207                                 s->what = strdup(s->parameters_proc_swaps.what);
 208                         else
 209                                 s->what = unit_name_to_path(u->meta.id);
 210
 211                         if (!s->what)
 212                                 return -ENOMEM;
 213                 }
 214
 215                 path_kill_slashes(s->what);
 216
 217                 if (!s->meta.description)
 218                         if ((r = unit_set_description(u, s->what)) < 0)
 219                                 return r;
 220
 221
 222                 if ((r = swap_add_device_links(s)) < 0)
 223                         return r;
 224
 225                 if ((r = swap_add_mount_links(s)) < 0)
 226                         return r;
 227
 228                 if ((r = swap_add_target_links(s)) < 0)
 229                         return r;
 230
 231                 if (s->meta.default_dependencies)
 232                         if ((r = swap_add_default_dependencies(s)) < 0)
 233                                 return r;
 234         }
 235
 236         return swap_verify(s);
 237 }
 238
 239 static int swap_find(Manager *m, const char *what, Unit **_u) {
 240         Unit *u;
 241         char *e;
 242
 243         assert(m);
 244         assert(what);
 245         assert(_u);
 246
 247         /* /proc/swaps and /etc/fstab might refer to this device by
 248          * different names (e.g. one by uuid, the other by the kernel
 249          * name), we hence need to look for all aliases we are aware
 250          * of for this device */
 251
 252         if (!(e = unit_name_from_path(what, ".device")))
 253                 return -ENOMEM;
 254
 255         u = manager_get_unit(m, e);
 256         free(e);
 257
 258         if (u) {
 259                 Iterator i;
 260                 const char *d;
 261
 262                 SET_FOREACH(d, u->meta.names, i) {
 263                         Unit *k;
 264
 265                         if (!(e = unit_name_change_suffix(d, ".swap")))
 266                                 return -ENOMEM;
 267
 268                         k = manager_get_unit(m, e);
 269                         free(e);
 270
 271                         if (k) {
 272                                 *_u = k;
 273                                 return 0;
 274                         }
 275                 }
 276         }
 277
 278         *_u = NULL;
 279         return 0;
 280 }
 281
 282 int swap_add_one(
 283                 Manager *m,
 284                 const char *what,
 285                 int priority,
 286                 bool noauto,
 287                 bool nofail,
 288                 bool handle,
 289                 bool from_proc_swaps) {
 290         Unit *u = NULL;
 291         char *e = NULL, *w = NULL;
 292         bool delete = false;
 293         int r;
 294         SwapParameters *p;
 295
 296         assert(m);
 297         assert(what);
 298
 299         if (!(e = unit_name_from_path(what, ".swap")))
 300                 return -ENOMEM;
 301
 302         if (!(u = manager_get_unit(m, e)))
 303                 if ((r = swap_find(m, what, &u)) < 0)
 304                         goto fail;
 305
 306         if (!u) {
 307                 delete = true;
 308
 309                 if (!(u = unit_new(m))) {
 310                         free(e);
 311                         return -ENOMEM;
 312                 }
 313         } else
 314                 delete = false;
 315
 316         if ((r = unit_add_name(u, e)) < 0)
 317                 goto fail;
 318
 319         if (!(w = strdup(what))) {
 320                 r = -ENOMEM;
 321                 goto fail;
 322         }
 323
 324         if (from_proc_swaps) {
 325                 p = &SWAP(u)->parameters_proc_swaps;
 326                 SWAP(u)->from_proc_swaps = true;
 327         } else {
 328                 p = &SWAP(u)->parameters_etc_fstab;
 329                 SWAP(u)->from_etc_fstab = true;
 330         }
 331
 332         free(p->what);
 333         p->what = w;
 334
 335         p->priority = priority;
 336         p->noauto = noauto;
 337         p->nofail = nofail;
 338         p->handle = handle;
 339
 340         if (delete)
 341                 unit_add_to_load_queue(u);
 342
 343         unit_add_to_dbus_queue(u);
 344
 345         free(e);
 346
 347         return 0;
 348
 349 fail:
 350         free(w);
 351         free(e);
 352
 353         if (delete && u)
 354                 unit_free(u);
 355
 356         return r;
 357 }
 358
 359 static void swap_set_state(Swap *s, SwapState state) {
 360         SwapState old_state;
 361         assert(s);
 362
 363         old_state = s->state;
 364         s->state = state;
 365
 366         if (state != old_state)
 367                 log_debug("%s changed %s -> %s",
 368                           s->meta.id,
 369                           swap_state_to_string(old_state),
 370                           swap_state_to_string(state));
 371
 372         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state]);
 373 }
 374
 375 static int swap_coldplug(Unit *u) {
 376         Swap *s = SWAP(u);
 377         SwapState new_state = SWAP_DEAD;
 378
 379         assert(s);
 380         assert(s->state == SWAP_DEAD);
 381
 382         if (s->deserialized_state != s->state)
 383                 new_state = s->deserialized_state;
 384         else if (s->from_proc_swaps)
 385                 new_state = SWAP_ACTIVE;
 386
 387         if (new_state != s->state)
 388                 swap_set_state(s, new_state);
 389
 390         return 0;
 391 }
 392
 393 static void swap_dump(Unit *u, FILE *f, const char *prefix) {
 394         Swap *s = SWAP(u);
 395         SwapParameters *p;
 396
 397         assert(s);
 398         assert(f);
 399
 400         if (s->from_proc_swaps)
 401                 p = &s->parameters_proc_swaps;
 402         else if (s->from_fragment)
 403                 p = &s->parameters_fragment;
 404         else
 405                 p = &s->parameters_etc_fstab;
 406
 407         fprintf(f,
 408                 "%sSwap State: %s\n"
 409                 "%sWhat: %s\n"
 410                 "%sPriority: %i\n"
 411                 "%sNoAuto: %s\n"
 412                 "%sNoFail: %s\n"
 413                 "%sHandle: %s\n"
 414                 "%sFrom /etc/fstab: %s\n"
 415                 "%sFrom /proc/swaps: %s\n"
 416                 "%sFrom fragment: %s\n",
 417                 prefix, swap_state_to_string(s->state),
 418                 prefix, s->what,
 419                 prefix, p->priority,
 420                 prefix, yes_no(p->noauto),
 421                 prefix, yes_no(p->nofail),
 422                 prefix, yes_no(p->handle),
 423                 prefix, yes_no(s->from_etc_fstab),
 424                 prefix, yes_no(s->from_proc_swaps),
 425                 prefix, yes_no(s->from_fragment));
 426 }
 427
 428 static void swap_enter_dead(Swap *s, bool success) {
 429         assert(s);
 430
 431         swap_set_state(s, success ? SWAP_DEAD : SWAP_FAILED);
 432 }
 433
 434 static int swap_start(Unit *u) {
 435         Swap *s = SWAP(u);
 436         int priority = -1;
 437         int r;
 438
 439         assert(s);
 440         assert(s->state == SWAP_DEAD || s->state == SWAP_FAILED);
 441
 442         if (s->from_fragment)
 443                 priority = s->parameters_fragment.priority;
 444         else if (s->from_etc_fstab)
 445                 priority = s->parameters_etc_fstab.priority;
 446
 447         r = swapon(s->what, (priority << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK);
 448
 449         if (r < 0 && errno != EBUSY) {
 450                 r = -errno;
 451                 swap_enter_dead(s, false);
 452                 return r;
 453         }
 454
 455         swap_set_state(s, SWAP_ACTIVE);
 456         return 0;
 457 }
 458
 459 static int swap_stop(Unit *u) {
 460         Swap *s = SWAP(u);
 461         int r;
 462
 463         assert(s);
 464
 465         assert(s->state == SWAP_ACTIVE);
 466
 467         r = swapoff(s->what);
 468         swap_enter_dead(s, r >= 0 || errno == EINVAL);
 469
 470         return 0;
 471 }
 472
 473 static int swap_serialize(Unit *u, FILE *f, FDSet *fds) {
 474         Swap *s = SWAP(u);
 475
 476         assert(s);
 477         assert(f);
 478         assert(fds);
 479
 480         unit_serialize_item(u, f, "state", swap_state_to_string(s->state));
 481
 482         return 0;
 483 }
 484
 485 static int swap_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 486         Swap *s = SWAP(u);
 487
 488         assert(s);
 489         assert(fds);
 490
 491         if (streq(key, "state")) {
 492                 SwapState state;
 493
 494                 if ((state = swap_state_from_string(value)) < 0)
 495                         log_debug("Failed to parse state value %s", value);
 496                 else
 497                         s->deserialized_state = state;
 498         } else
 499                 log_debug("Unknown serialization key '%s'", key);
 500
 501         return 0;
 502 }
 503
 504 static UnitActiveState swap_active_state(Unit *u) {
 505         assert(u);
 506
 507         return state_translation_table[SWAP(u)->state];
 508 }
 509
 510 static const char *swap_sub_state_to_string(Unit *u) {
 511         assert(u);
 512
 513         return swap_state_to_string(SWAP(u)->state);
 514 }
 515
 516 static bool swap_check_gc(Unit *u) {
 517         Swap *s = SWAP(u);
 518
 519         assert(s);
 520
 521         return s->from_etc_fstab || s->from_proc_swaps;
 522 }
 523
 524 static int swap_load_proc_swaps(Manager *m) {
 525         rewind(m->proc_swaps);
 526
 527         (void) fscanf(m->proc_swaps, "%*s %*s %*s %*s %*s\n");
 528
 529         for (;;) {
 530                 char *dev = NULL, *d;
 531                 int prio = 0, k;
 532
 533                 if ((k = fscanf(m->proc_swaps,
 534                                 "%ms " /* device/file */
 535                                 "%*s " /* type of swap */
 536                                 "%*s " /* swap size */
 537                                 "%*s " /* used */
 538                                 "%i\n", /* priority */
 539                                 &dev, &prio)) != 2) {
 540
 541                         if (k == EOF)
 542                                 break;
 543
 544                         free(dev);
 545                         return -EBADMSG;
 546                 }
 547
 548                 d = cunescape(dev);
 549                 free(dev);
 550
 551                 if (!d)
 552                         return -ENOMEM;
 553
 554                 k = swap_add_one(m, d, prio, false, false, false, true);
 555                 free(d);
 556
 557                 if (k < 0)
 558                         return k;
 559         }
 560
 561         return 0;
 562 }
 563
 564 static void swap_shutdown(Manager *m) {
 565         assert(m);
 566
 567         if (m->proc_swaps) {
 568                 fclose(m->proc_swaps);
 569                 m->proc_swaps = NULL;
 570         }
 571 }
 572
 573 static int swap_enumerate(Manager *m) {
 574         int r;
 575         assert(m);
 576
 577         if (!m->proc_swaps)
 578                 if (!(m->proc_swaps = fopen("/proc/swaps", "re")))
 579                         return -errno;
 580
 581         if ((r = swap_load_proc_swaps(m)) < 0)
 582                 swap_shutdown(m);
 583
 584         return r;
 585 }
 586
 587 static void swap_reset_failed(Unit *u) {
 588         Swap *s = SWAP(u);
 589
 590         assert(s);
 591
 592         if (s->state == SWAP_FAILED)
 593                 swap_set_state(s, SWAP_DEAD);
 594 }
 595
 596 static const char* const swap_state_table[_SWAP_STATE_MAX] = {
 597         [SWAP_DEAD] = "dead",
 598         [SWAP_ACTIVE] = "active",
 599         [SWAP_FAILED] = "failed"
 600 };
 601
 602 DEFINE_STRING_TABLE_LOOKUP(swap_state, SwapState);
 603
 604 const UnitVTable swap_vtable = {
 605         .suffix = ".swap",
 606
 607         .no_instances = true,
 608         .no_isolate = true,
 609         .show_status = true,
 610
 611         .init = swap_init,
 612         .load = swap_load,
 613         .done = swap_done,
 614
 615         .coldplug = swap_coldplug,
 616
 617         .dump = swap_dump,
 618
 619         .start = swap_start,
 620         .stop = swap_stop,
 621
 622         .serialize = swap_serialize,
 623         .deserialize_item = swap_deserialize_item,
 624
 625         .active_state = swap_active_state,
 626         .sub_state_to_string = swap_sub_state_to_string,
 627
 628         .check_gc = swap_check_gc,
 629
 630         .bus_interface = "org.freedesktop.systemd1.Swap",
 631         .bus_message_handler = bus_swap_message_handler,
 632         .bus_invalidating_properties =  bus_swap_invalidating_properties,
 633
 634         .reset_failed = swap_reset_failed,
 635
 636         .enumerate = swap_enumerate,
 637         .shutdown = swap_shutdown
 638 };