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
  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 (is_device_path(s->what))
  74                 return 0;
  75
  76         if (!path_startswith(s->what, m->where))
  77                 return 0;
  78
  79         if ((r = unit_add_dependency(UNIT(m), UNIT_BEFORE, UNIT(s), true)) < 0)
  80                 return r;
  81
  82         if ((r = unit_add_dependency(UNIT(s), UNIT_REQUIRES, UNIT(m), true)) < 0)
  83                 return r;
  84
  85         return 0;
  86 }
  87
  88 static int swap_add_mount_links(Swap *s) {
  89         Meta *other;
  90         int r;
  91
  92         assert(s);
  93
  94         LIST_FOREACH(units_per_type, other, s->meta.manager->units_per_type[UNIT_MOUNT])
  95                 if ((r = swap_add_one_mount_link(s, (Mount*) other)) < 0)
  96                         return r;
  97
  98         return 0;
  99 }
 100
 101 static int swap_add_target_links(Swap *s) {
 102         Unit *tu;
 103         SwapParameters *p;
 104         int r;
 105
 106         assert(s);
 107
 108         if (s->from_fragment)
 109                 p = &s->parameters_fragment;
 110         else if (s->from_etc_fstab)
 111                 p = &s->parameters_etc_fstab;
 112         else
 113                 return 0;
 114
 115         if ((r = manager_load_unit(s->meta.manager, SPECIAL_SWAP_TARGET, NULL, &tu)) < 0)
 116                 return r;
 117
 118         if (!p->noauto && p->handle && s->meta.manager->running_as != MANAGER_SESSION)
 119                 if ((r = unit_add_dependency(tu, UNIT_WANTS, UNIT(s), true)) < 0)
 120                         return r;
 121
 122         return unit_add_dependency(UNIT(s), UNIT_BEFORE, tu, true);
 123 }
 124
 125 static int swap_verify(Swap *s) {
 126         bool b;
 127         char *e;
 128
 129         if (UNIT(s)->meta.load_state != UNIT_LOADED)
 130                   return 0;
 131
 132         if (!(e = unit_name_from_path(s->what, ".swap")))
 133                   return -ENOMEM;
 134
 135         b = unit_has_name(UNIT(s), e);
 136         free(e);
 137
 138         if (!b) {
 139                 log_error("%s: Value of \"What\" and unit name do not match, not loading.\n", UNIT(s)->meta.id);
 140                 return -EINVAL;
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int swap_load(Unit *u) {
 147         int r;
 148         Swap *s = SWAP(u);
 149
 150         assert(s);
 151         assert(u->meta.load_state == UNIT_STUB);
 152
 153         /* Load a .swap file */
 154         if ((r = unit_load_fragment_and_dropin_optional(u)) < 0)
 155                 return r;
 156
 157         if (u->meta.load_state == UNIT_LOADED) {
 158
 159                 if (s->meta.fragment_path)
 160                         s->from_fragment = true;
 161
 162                 if (!s->what) {
 163                         if (s->parameters_fragment.what)
 164                                 s->what = strdup(s->parameters_fragment.what);
 165                         else if (s->parameters_etc_fstab.what)
 166                                 s->what = strdup(s->parameters_etc_fstab.what);
 167                         else if (s->parameters_proc_swaps.what)
 168                                 s->what = strdup(s->parameters_proc_swaps.what);
 169                         else
 170                                 s->what = unit_name_to_path(u->meta.id);
 171
 172                         if (!s->what)
 173                                 return -ENOMEM;
 174                 }
 175
 176                 path_kill_slashes(s->what);
 177
 178                 if (!s->meta.description)
 179                         if ((r = unit_set_description(u, s->what)) < 0)
 180                                 return r;
 181
 182                 if ((r = unit_add_node_link(u, s->what,
 183                                             (u->meta.manager->running_as == MANAGER_INIT ||
 184                                              u->meta.manager->running_as == MANAGER_SYSTEM))) < 0)
 185                         return r;
 186
 187                 if ((r = swap_add_mount_links(s)) < 0)
 188                         return r;
 189
 190                 if ((r = swap_add_target_links(s)) < 0)
 191                         return r;
 192         }
 193
 194         return swap_verify(s);
 195 }
 196
 197 static int swap_find(Manager *m, const char *what, Unit **_u) {
 198         Unit *u;
 199         char *e;
 200
 201         assert(m);
 202         assert(what);
 203         assert(_u);
 204
 205         /* /proc/swaps and /etc/fstab might refer to this device by
 206          * different names (e.g. one by uuid, the other by the kernel
 207          * name), we hence need to look for all aliases we are aware
 208          * of for this device */
 209
 210         if (!(e = unit_name_from_path(what, ".device")))
 211                 return -ENOMEM;
 212
 213         u = manager_get_unit(m, e);
 214         free(e);
 215
 216         if (u) {
 217                 Iterator i;
 218                 const char *d;
 219
 220                 SET_FOREACH(d, u->meta.names, i) {
 221                         Unit *k;
 222
 223                         if (!(e = unit_name_change_suffix(d, ".swap")))
 224                                 return -ENOMEM;
 225
 226                         k = manager_get_unit(m, e);
 227                         free(e);
 228
 229                         if (k) {
 230                                 *_u = k;
 231                                 return 0;
 232                         }
 233                 }
 234         }
 235
 236         *_u = NULL;
 237         return 0;
 238 }
 239
 240 int swap_add_one(
 241                 Manager *m,
 242                 const char *what,
 243                 int priority,
 244                 bool noauto,
 245                 bool handle,
 246                 bool from_proc_swaps) {
 247         Unit *u = NULL;
 248         char *e = NULL, *w = NULL;
 249         bool delete;
 250         int r;
 251         SwapParameters *p;
 252
 253         assert(m);
 254         assert(what);
 255
 256         if (!(e = unit_name_from_path(what, ".swap")))
 257                 return -ENOMEM;
 258
 259         if (!(u = manager_get_unit(m, e)))
 260                 if ((r = swap_find(m, what, &u)) < 0)
 261                         goto fail;
 262
 263         if (!u) {
 264                 delete = true;
 265
 266                 if (!(u = unit_new(m))) {
 267                         free(e);
 268                         return -ENOMEM;
 269                 }
 270         } else
 271                 delete = false;
 272
 273         if ((r = unit_add_name(u, e)) < 0)
 274                 goto fail;
 275
 276         if (!(w = strdup(what))) {
 277                 r = -ENOMEM;
 278                 goto fail;
 279         }
 280
 281         if (from_proc_swaps) {
 282                 p = &SWAP(u)->parameters_proc_swaps;
 283                 SWAP(u)->from_proc_swaps = true;
 284         } else {
 285                 p = &SWAP(u)->parameters_etc_fstab;
 286                 SWAP(u)->from_etc_fstab = true;
 287         }
 288
 289         free(p->what);
 290         p->what = w;
 291
 292         p->priority = priority;
 293         p->noauto = noauto;
 294         p->handle = handle;
 295
 296         if (delete)
 297                 unit_add_to_load_queue(u);
 298
 299         unit_add_to_dbus_queue(u);
 300
 301         free(e);
 302
 303         return 0;
 304
 305 fail:
 306         free(w);
 307         free(e);
 308
 309         if (delete && u)
 310                 unit_free(u);
 311
 312         return r;
 313 }
 314
 315 static void swap_set_state(Swap *s, SwapState state) {
 316         SwapState old_state;
 317         assert(s);
 318
 319         old_state = s->state;
 320         s->state = state;
 321
 322         if (state != old_state)
 323                 log_debug("%s changed %s -> %s",
 324                           UNIT(s)->meta.id,
 325                           swap_state_to_string(old_state),
 326                           swap_state_to_string(state));
 327
 328         unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state]);
 329 }
 330
 331 static int swap_coldplug(Unit *u) {
 332         Swap *s = SWAP(u);
 333         SwapState new_state = SWAP_DEAD;
 334
 335         assert(s);
 336         assert(s->state == SWAP_DEAD);
 337
 338         if (s->deserialized_state != s->state)
 339                 new_state = s->deserialized_state;
 340         else if (s->from_proc_swaps)
 341                 new_state = SWAP_ACTIVE;
 342
 343         if (new_state != s->state)
 344                 swap_set_state(s, new_state);
 345
 346         return 0;
 347 }
 348
 349 static void swap_dump(Unit *u, FILE *f, const char *prefix) {
 350         Swap *s = SWAP(u);
 351         SwapParameters *p;
 352
 353         assert(s);
 354         assert(f);
 355
 356         if (s->from_proc_swaps)
 357                 p = &s->parameters_proc_swaps;
 358         else if (s->from_fragment)
 359                 p = &s->parameters_fragment;
 360         else
 361                 p = &s->parameters_etc_fstab;
 362
 363         fprintf(f,
 364                 "%sSwap State: %s\n"
 365                 "%sWhat: %s\n"
 366                 "%sPriority: %i\n"
 367                 "%sNoAuto: %s\n"
 368                 "%sHandle: %s\n"
 369                 "%sFrom /etc/fstab: %s\n"
 370                 "%sFrom /proc/swaps: %s\n"
 371                 "%sFrom fragment: %s\n",
 372                 prefix, swap_state_to_string(s->state),
 373                 prefix, s->what,
 374                 prefix, p->priority,
 375                 prefix, yes_no(p->noauto),
 376                 prefix, yes_no(p->handle),
 377                 prefix, yes_no(s->from_etc_fstab),
 378                 prefix, yes_no(s->from_proc_swaps),
 379                 prefix, yes_no(s->from_fragment));
 380 }
 381
 382 static void swap_enter_dead(Swap *s, bool success) {
 383         assert(s);
 384
 385         swap_set_state(s, success ? SWAP_MAINTAINANCE : SWAP_DEAD);
 386 }
 387
 388 static int swap_start(Unit *u) {
 389         Swap *s = SWAP(u);
 390         int priority = -1;
 391         int r;
 392
 393         assert(s);
 394         assert(s->state == SWAP_DEAD || s->state == SWAP_MAINTAINANCE);
 395
 396         if (s->from_fragment)
 397                 priority = s->parameters_fragment.priority;
 398         else if (s->from_etc_fstab)
 399                 priority = s->parameters_etc_fstab.priority;
 400
 401         r = swapon(s->what, (priority << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK);
 402
 403         if (r < 0 && errno != EBUSY) {
 404                 r = -errno;
 405                 swap_enter_dead(s, false);
 406                 return r;
 407         }
 408
 409         swap_set_state(s, SWAP_ACTIVE);
 410         return 0;
 411 }
 412
 413 static int swap_stop(Unit *u) {
 414         Swap *s = SWAP(u);
 415         int r;
 416
 417         assert(s);
 418
 419         assert(s->state == SWAP_ACTIVE);
 420
 421         r = swapoff(s->what);
 422         swap_enter_dead(s, r >= 0 || errno == EINVAL);
 423
 424         return 0;
 425 }
 426
 427 static int swap_serialize(Unit *u, FILE *f, FDSet *fds) {
 428         Swap *s = SWAP(u);
 429
 430         assert(s);
 431         assert(f);
 432         assert(fds);
 433
 434         unit_serialize_item(u, f, "state", swap_state_to_string(s->state));
 435
 436         return 0;
 437 }
 438
 439 static int swap_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 440         Swap *s = SWAP(u);
 441
 442         assert(s);
 443         assert(fds);
 444
 445         if (streq(key, "state")) {
 446                 SwapState state;
 447
 448                 if ((state = swap_state_from_string(value)) < 0)
 449                         log_debug("Failed to parse state value %s", value);
 450                 else
 451                         s->deserialized_state = state;
 452         } else
 453                 log_debug("Unknown serialization key '%s'", key);
 454
 455         return 0;
 456 }
 457
 458 static UnitActiveState swap_active_state(Unit *u) {
 459         assert(u);
 460
 461         return state_translation_table[SWAP(u)->state];
 462 }
 463
 464 static const char *swap_sub_state_to_string(Unit *u) {
 465         assert(u);
 466
 467         return swap_state_to_string(SWAP(u)->state);
 468 }
 469
 470 static bool swap_check_gc(Unit *u) {
 471         Swap *s = SWAP(u);
 472
 473         assert(s);
 474
 475         return s->from_etc_fstab || s->from_proc_swaps;
 476 }
 477
 478 static int swap_load_proc_swaps(Manager *m) {
 479         rewind(m->proc_swaps);
 480
 481         (void) fscanf(m->proc_swaps, "%*s %*s %*s %*s %*s\n");
 482
 483         for (;;) {
 484                 char *dev = NULL, *d;
 485                 int prio = 0, k;
 486
 487                 if ((k = fscanf(m->proc_swaps,
 488                                 "%ms " /* device/file */
 489                                 "%*s " /* type of swap */
 490                                 "%*s " /* swap size */
 491                                 "%*s " /* used */
 492                                 "%i\n", /* priority */
 493                                 &dev, &prio)) != 2) {
 494
 495                         if (k == EOF)
 496                                 break;
 497
 498                         free(dev);
 499                         return -EBADMSG;
 500                 }
 501
 502                 d = cunescape(dev);
 503                 free(dev);
 504
 505                 if (!d)
 506                         return -ENOMEM;
 507
 508                 k = swap_add_one(m, d, prio, false, false, true);
 509                 free(d);
 510
 511                 if (k < 0)
 512                         return k;
 513         }
 514
 515         return 0;
 516 }
 517
 518 static void swap_shutdown(Manager *m) {
 519         assert(m);
 520
 521         if (m->proc_swaps) {
 522                 fclose(m->proc_swaps);
 523                 m->proc_swaps = NULL;
 524         }
 525 }
 526
 527 static const char* const swap_state_table[_SWAP_STATE_MAX] = {
 528         [SWAP_DEAD] = "dead",
 529         [SWAP_ACTIVE] = "active",
 530         [SWAP_MAINTAINANCE] = "maintainance"
 531 };
 532
 533 DEFINE_STRING_TABLE_LOOKUP(swap_state, SwapState);
 534
 535 static int swap_enumerate(Manager *m) {
 536         int r;
 537         assert(m);
 538
 539         if (!m->proc_swaps)
 540                 if (!(m->proc_swaps = fopen("/proc/swaps", "re")))
 541                         return -errno;
 542
 543         if ((r = swap_load_proc_swaps(m)) < 0)
 544                 swap_shutdown(m);
 545
 546         return r;
 547 }
 548
 549 const UnitVTable swap_vtable = {
 550         .suffix = ".swap",
 551
 552         .no_instances = true,
 553         .no_isolate = true,
 554
 555         .init = swap_init,
 556         .load = swap_load,
 557         .done = swap_done,
 558
 559         .coldplug = swap_coldplug,
 560
 561         .dump = swap_dump,
 562
 563         .start = swap_start,
 564         .stop = swap_stop,
 565
 566         .serialize = swap_serialize,
 567         .deserialize_item = swap_deserialize_item,
 568
 569         .active_state = swap_active_state,
 570         .sub_state_to_string = swap_sub_state_to_string,
 571
 572         .check_gc = swap_check_gc,
 573
 574         .bus_message_handler = bus_swap_message_handler,
 575
 576         .enumerate = swap_enumerate,
 577         .shutdown = swap_shutdown
 578 };