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