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