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