src/path.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 <sys/inotify.h>
  23 #include <sys/epoll.h>
  24 #include <sys/ioctl.h>
  25 #include <errno.h>
  26 #include <unistd.h>
  27
  28 #include "unit.h"
  29 #include "unit-name.h"
  30 #include "path.h"
  31 #include "dbus-path.h"
  32 #include "special.h"
  33 #include "bus-errors.h"
  34
  35 static const UnitActiveState state_translation_table[_PATH_STATE_MAX] = {
  36         [PATH_DEAD] = UNIT_INACTIVE,
  37         [PATH_WAITING] = UNIT_ACTIVE,
  38         [PATH_RUNNING] = UNIT_ACTIVE,
  39         [PATH_MAINTENANCE] = UNIT_MAINTENANCE
  40 };
  41
  42 static void path_done(Unit *u) {
  43         Path *p = PATH(u);
  44         PathSpec *s;
  45
  46         assert(p);
  47
  48         while ((s = p->specs)) {
  49                 LIST_REMOVE(PathSpec, spec, p->specs, s);
  50                 free(s);
  51         }
  52 }
  53
  54 int path_add_one_mount_link(Path *p, Mount *m) {
  55         PathSpec *s;
  56         int r;
  57
  58         assert(p);
  59         assert(m);
  60
  61         if (p->meta.load_state != UNIT_LOADED ||
  62             m->meta.load_state != UNIT_LOADED)
  63                 return 0;
  64
  65         LIST_FOREACH(spec, s, p->specs) {
  66
  67                 if (!path_startswith(s->path, m->where))
  68                         continue;
  69
  70                 if ((r = unit_add_two_dependencies(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, UNIT(m), true)) < 0)
  71                         return r;
  72         }
  73
  74         return 0;
  75 }
  76
  77 static int path_add_mount_links(Path *p) {
  78         Meta *other;
  79         int r;
  80
  81         assert(p);
  82
  83         LIST_FOREACH(units_per_type, other, p->meta.manager->units_per_type[UNIT_MOUNT])
  84                 if ((r = path_add_one_mount_link(p, (Mount*) other)) < 0)
  85                         return r;
  86
  87         return 0;
  88 }
  89
  90 static int path_verify(Path *p) {
  91         assert(p);
  92
  93         if (p->meta.load_state != UNIT_LOADED)
  94                 return 0;
  95
  96         if (!p->specs) {
  97                 log_error("%s lacks path setting. Refusing.", p->meta.id);
  98                 return -EINVAL;
  99         }
 100
 101         return 0;
 102 }
 103
 104 static int path_add_default_dependencies(Path *p) {
 105         int r;
 106
 107         assert(p);
 108
 109         if (p->meta.manager->running_as == MANAGER_SYSTEM)
 110                 if ((r = unit_add_two_dependencies_by_name(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true)) < 0)
 111                         return r;
 112
 113         return unit_add_two_dependencies_by_name(UNIT(p), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
 114 }
 115
 116 static int path_load(Unit *u) {
 117         Path *p = PATH(u);
 118         int r;
 119
 120         assert(u);
 121         assert(u->meta.load_state == UNIT_STUB);
 122
 123         if ((r = unit_load_fragment_and_dropin(u)) < 0)
 124                 return r;
 125
 126         if (u->meta.load_state == UNIT_LOADED) {
 127
 128                 if (!p->unit)
 129                         if ((r = unit_load_related_unit(u, ".service", &p->unit)))
 130                                 return r;
 131
 132                 if ((r = unit_add_dependency(u, UNIT_BEFORE, p->unit, true)) < 0)
 133                         return r;
 134
 135                 if ((r = path_add_mount_links(p)) < 0)
 136                         return r;
 137
 138                 if (p->meta.default_dependencies)
 139                         if ((r = path_add_default_dependencies(p)) < 0)
 140                                 return r;
 141         }
 142
 143         return path_verify(p);
 144 }
 145
 146 static void path_dump(Unit *u, FILE *f, const char *prefix) {
 147         Path *p = PATH(u);
 148         const char *prefix2;
 149         char *p2;
 150         PathSpec *s;
 151
 152         p2 = strappend(prefix, "\t");
 153         prefix2 = p2 ? p2 : prefix;
 154
 155         fprintf(f,
 156                 "%sPath State: %s\n"
 157                 "%sUnit: %s\n",
 158                 prefix, path_state_to_string(p->state),
 159                 prefix, p->unit->meta.id);
 160
 161         LIST_FOREACH(spec, s, p->specs)
 162                 fprintf(f,
 163                         "%s%s: %s\n",
 164                         prefix,
 165                         path_type_to_string(s->type),
 166                         s->path);
 167
 168         free(p2);
 169 }
 170
 171 static void path_unwatch_one(Path *p, PathSpec *s) {
 172
 173         if (s->inotify_fd < 0)
 174                 return;
 175
 176         unit_unwatch_fd(UNIT(p), &s->watch);
 177
 178         close_nointr_nofail(s->inotify_fd);
 179         s->inotify_fd = -1;
 180 }
 181
 182 static int path_watch_one(Path *p, PathSpec *s) {
 183         static const int flags_table[_PATH_TYPE_MAX] = {
 184                 [PATH_EXISTS] = IN_DELETE_SELF|IN_MOVE_SELF,
 185                 [PATH_CHANGED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO,
 186                 [PATH_DIRECTORY_NOT_EMPTY] = IN_DELETE_SELF|IN_MOVE_SELF|IN_CREATE|IN_MOVED_TO
 187         };
 188
 189         bool exists = false;
 190         char *k;
 191         int r;
 192
 193         assert(p);
 194         assert(s);
 195
 196         path_unwatch_one(p, s);
 197
 198         if (!(k = strdup(s->path)))
 199                 return -ENOMEM;
 200
 201         if ((s->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC)) < 0) {
 202                 r = -errno;
 203                 goto fail;
 204         }
 205
 206         if (unit_watch_fd(UNIT(p), s->inotify_fd, EPOLLIN, &s->watch) < 0) {
 207                 r = -errno;
 208                 goto fail;
 209         }
 210
 211         if ((s->primary_wd = inotify_add_watch(s->inotify_fd, k, flags_table[s->type])) >= 0)
 212                 exists = true;
 213
 214         for (;;) {
 215                 int flags;
 216                 char *slash;
 217
 218                 /* This assumes the path was passed through path_kill_slashes()! */
 219                 if (!(slash = strrchr(k, '/')))
 220                         break;
 221
 222                 *slash = 0;
 223
 224                 flags = IN_DELETE_SELF|IN_MOVE_SELF;
 225                 if (!exists)
 226                         flags |= IN_CREATE | IN_MOVED_TO | IN_ATTRIB;
 227
 228                 if (inotify_add_watch(s->inotify_fd, k, flags) >= 0)
 229                         exists = true;
 230         }
 231
 232         return 0;
 233
 234 fail:
 235         free(k);
 236
 237         path_unwatch_one(p, s);
 238         return r;
 239 }
 240
 241 static void path_unwatch(Path *p) {
 242         PathSpec *s;
 243
 244         assert(p);
 245
 246         LIST_FOREACH(spec, s, p->specs)
 247                 path_unwatch_one(p, s);
 248 }
 249
 250 static int path_watch(Path *p) {
 251         int r;
 252         PathSpec *s;
 253
 254         assert(p);
 255
 256         LIST_FOREACH(spec, s, p->specs)
 257                 if ((r = path_watch_one(p, s)) < 0)
 258                         return r;
 259
 260         return 0;
 261 }
 262
 263 static void path_set_state(Path *p, PathState state) {
 264         PathState old_state;
 265         assert(p);
 266
 267         old_state = p->state;
 268         p->state = state;
 269
 270         if (state != PATH_WAITING)
 271                 path_unwatch(p);
 272
 273         if (state != old_state)
 274                 log_debug("%s changed %s -> %s",
 275                           p->meta.id,
 276                           path_state_to_string(old_state),
 277                           path_state_to_string(state));
 278
 279         unit_notify(UNIT(p), state_translation_table[old_state], state_translation_table[state]);
 280 }
 281
 282 static void path_enter_waiting(Path *p, bool initial);
 283
 284 static int path_coldplug(Unit *u) {
 285         Path *p = PATH(u);
 286
 287         assert(p);
 288         assert(p->state == PATH_DEAD);
 289
 290         if (p->deserialized_state != p->state) {
 291
 292                 if (p->deserialized_state == PATH_WAITING ||
 293                     p->deserialized_state == PATH_RUNNING)
 294                         path_enter_waiting(p, true);
 295                 else
 296                         path_set_state(p, p->deserialized_state);
 297         }
 298
 299         return 0;
 300 }
 301
 302 static void path_enter_dead(Path *p, bool success) {
 303         assert(p);
 304
 305         if (!success)
 306                 p->failure = true;
 307
 308         path_set_state(p, p->failure ? PATH_MAINTENANCE : PATH_DEAD);
 309 }
 310
 311 static void path_enter_running(Path *p) {
 312         int r;
 313         DBusError error;
 314
 315         assert(p);
 316         dbus_error_init(&error);
 317
 318         /* Don't start job if we are supposed to go down */
 319         if (p->meta.job && p->meta.job->type == JOB_STOP)
 320                 return;
 321
 322         if ((r = manager_add_job(p->meta.manager, JOB_START, p->unit, JOB_REPLACE, true, &error, NULL)) < 0)
 323                 goto fail;
 324
 325         path_set_state(p, PATH_RUNNING);
 326         return;
 327
 328 fail:
 329         log_warning("%s failed to queue unit startup job: %s", p->meta.id, bus_error(&error, r));
 330         path_enter_dead(p, false);
 331
 332         dbus_error_free(&error);
 333 }
 334
 335
 336 static void path_enter_waiting(Path *p, bool initial) {
 337         PathSpec *s;
 338         int r;
 339         bool good = false;
 340
 341         LIST_FOREACH(spec, s, p->specs) {
 342
 343                 switch (s->type) {
 344
 345                 case PATH_EXISTS:
 346                         good = access(s->path, F_OK) >= 0;
 347                         break;
 348
 349                 case PATH_DIRECTORY_NOT_EMPTY:
 350                         good = dir_is_empty(s->path) == 0;
 351                         break;
 352
 353                 case PATH_CHANGED: {
 354                         bool b;
 355
 356                         b = access(s->path, F_OK) >= 0;
 357                         good = !initial && b != s->previous_exists;
 358                         s->previous_exists = b;
 359                         break;
 360                 }
 361
 362                 default:
 363                         ;
 364                 }
 365
 366                 if (good)
 367                         break;
 368         }
 369
 370         if (good) {
 371                 path_enter_running(p);
 372                 return;
 373         }
 374
 375         if ((r = path_watch(p)) < 0)
 376                 goto fail;
 377
 378         path_set_state(p, PATH_WAITING);
 379         return;
 380
 381 fail:
 382         log_warning("%s failed to enter waiting state: %s", p->meta.id, strerror(-r));
 383         path_enter_dead(p, false);
 384 }
 385
 386 static int path_start(Unit *u) {
 387         Path *p = PATH(u);
 388
 389         assert(p);
 390         assert(p->state == PATH_DEAD || p->state == PATH_MAINTENANCE);
 391
 392         if (p->unit->meta.load_state != UNIT_LOADED)
 393                 return -ENOENT;
 394
 395         p->failure = false;
 396 path_enter_waiting(p, true);
 397         return 0;
 398 }
 399
 400 static int path_stop(Unit *u) {
 401         Path *p = PATH(u);
 402
 403         assert(p);
 404         assert(p->state == PATH_WAITING || p->state == PATH_RUNNING);
 405
 406         path_enter_dead(p, true);
 407         return 0;
 408 }
 409
 410 static int path_serialize(Unit *u, FILE *f, FDSet *fds) {
 411         Path *p = PATH(u);
 412
 413         assert(u);
 414         assert(f);
 415         assert(fds);
 416
 417         unit_serialize_item(u, f, "state", path_state_to_string(p->state));
 418
 419         return 0;
 420 }
 421
 422 static int path_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 423         Path *p = PATH(u);
 424
 425         assert(u);
 426         assert(key);
 427         assert(value);
 428         assert(fds);
 429
 430         if (streq(key, "state")) {
 431                 PathState state;
 432
 433                 if ((state = path_state_from_string(value)) < 0)
 434                         log_debug("Failed to parse state value %s", value);
 435                 else
 436                         p->deserialized_state = state;
 437         } else
 438                 log_debug("Unknown serialization key '%s'", key);
 439
 440         return 0;
 441 }
 442
 443 static UnitActiveState path_active_state(Unit *u) {
 444         assert(u);
 445
 446         return state_translation_table[PATH(u)->state];
 447 }
 448
 449 static const char *path_sub_state_to_string(Unit *u) {
 450         assert(u);
 451
 452         return path_state_to_string(PATH(u)->state);
 453 }
 454
 455 static void path_fd_event(Unit *u, int fd, uint32_t events, Watch *w) {
 456         Path *p = PATH(u);
 457         int l;
 458         ssize_t k;
 459         struct inotify_event *buf = NULL;
 460         PathSpec *s;
 461
 462         assert(p);
 463         assert(fd >= 0);
 464
 465         if (p->state != PATH_WAITING)
 466                 return;
 467
 468         log_debug("inotify wakeup on %s.", u->meta.id);
 469
 470         if (events != EPOLLIN) {
 471                 log_error("Got Invalid poll event on inotify.");
 472                 goto fail;
 473         }
 474
 475         LIST_FOREACH(spec, s, p->specs)
 476                 if (s->inotify_fd == fd)
 477                         break;
 478
 479         if (!s) {
 480                 log_error("Got event on unknown fd.");
 481                 goto fail;
 482         }
 483
 484         if (ioctl(fd, FIONREAD, &l) < 0) {
 485                 log_error("FIONREAD failed: %s", strerror(errno));
 486                 goto fail;
 487         }
 488
 489         if (!(buf = malloc(l))) {
 490                 log_error("Failed to allocate buffer: %s", strerror(-ENOMEM));
 491                 goto fail;
 492         }
 493
 494         if ((k = read(fd, buf, l)) < 0) {
 495                 log_error("Failed to read inotify event: %s", strerror(-errno));
 496                 goto fail;
 497         }
 498
 499         if ((size_t) k < sizeof(struct inotify_event) ||
 500             (size_t) k < sizeof(struct inotify_event) + buf->len) {
 501                 log_error("inotify event too small.");
 502                 goto fail;
 503         }
 504
 505         if (s->type == PATH_CHANGED && s->primary_wd == buf->wd)
 506                 path_enter_running(p);
 507         else
 508                 path_enter_waiting(p, false);
 509
 510         free(buf);
 511
 512         return;
 513
 514 fail:
 515         free(buf);
 516         path_enter_dead(p, false);
 517 }
 518
 519 void path_unit_notify(Unit *u, UnitActiveState new_state) {
 520         char *n;
 521         int r;
 522         Iterator i;
 523
 524         if (u->meta.type == UNIT_PATH)
 525                 return;
 526
 527         SET_FOREACH(n, u->meta.names, i) {
 528                 char *k;
 529                 Unit *t;
 530                 Path *p;
 531
 532                 if (!(k = unit_name_change_suffix(n, ".path"))) {
 533                         r = -ENOMEM;
 534                         goto fail;
 535                 }
 536
 537                 t = manager_get_unit(u->meta.manager, k);
 538                 free(k);
 539
 540                 if (!t)
 541                         continue;
 542
 543                 if (t->meta.load_state != UNIT_LOADED)
 544                         continue;
 545
 546                 p = PATH(t);
 547
 548                 if (p->unit != u)
 549                         continue;
 550
 551                 if (p->state == PATH_RUNNING && new_state == UNIT_INACTIVE) {
 552                         log_debug("%s got notified about unit deactivation.", p->meta.id);
 553                         path_enter_waiting(p, false);
 554                 }
 555         }
 556
 557         return;
 558
 559 fail:
 560         log_error("Failed find path unit: %s", strerror(-r));
 561 }
 562
 563 static void path_reset_maintenance(Unit *u) {
 564         Path *p = PATH(u);
 565
 566         assert(p);
 567
 568         if (p->state == PATH_MAINTENANCE)
 569                 path_set_state(p, PATH_DEAD);
 570
 571         p->failure = false;
 572 }
 573
 574 static const char* const path_state_table[_PATH_STATE_MAX] = {
 575         [PATH_DEAD] = "dead",
 576         [PATH_WAITING] = "waiting",
 577         [PATH_RUNNING] = "running",
 578         [PATH_MAINTENANCE] = "maintenance"
 579 };
 580
 581 DEFINE_STRING_TABLE_LOOKUP(path_state, PathState);
 582
 583 static const char* const path_type_table[_PATH_TYPE_MAX] = {
 584         [PATH_EXISTS] = "PathExists",
 585         [PATH_CHANGED] = "PathChanged",
 586         [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty"
 587 };
 588
 589 DEFINE_STRING_TABLE_LOOKUP(path_type, PathType);
 590
 591 const UnitVTable path_vtable = {
 592         .suffix = ".path",
 593
 594         .done = path_done,
 595         .load = path_load,
 596
 597         .coldplug = path_coldplug,
 598
 599         .dump = path_dump,
 600
 601         .start = path_start,
 602         .stop = path_stop,
 603
 604         .serialize = path_serialize,
 605         .deserialize_item = path_deserialize_item,
 606
 607         .active_state = path_active_state,
 608         .sub_state_to_string = path_sub_state_to_string,
 609
 610         .fd_event = path_fd_event,
 611
 612         .reset_maintenance = path_reset_maintenance,
 613
 614         .bus_message_handler = bus_path_message_handler
 615 };