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