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