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