src/path.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   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_FAILED] = UNIT_FAILED
  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_CONFLICTED_BY, 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         PathSpec *s;
 149
 150         assert(p);
 151         assert(f);
 152
 153         fprintf(f,
 154                 "%sPath State: %s\n"
 155                 "%sUnit: %s\n",
 156                 prefix, path_state_to_string(p->state),
 157                 prefix, p->unit->meta.id);
 158
 159         LIST_FOREACH(spec, s, p->specs)
 160                 fprintf(f,
 161                         "%s%s: %s\n",
 162                         prefix,
 163                         path_type_to_string(s->type),
 164                         s->path);
 165 }
 166
 167 static void path_unwatch_one(Path *p, PathSpec *s) {
 168
 169         if (s->inotify_fd < 0)
 170                 return;
 171
 172         unit_unwatch_fd(UNIT(p), &s->watch);
 173
 174         close_nointr_nofail(s->inotify_fd);
 175         s->inotify_fd = -1;
 176 }
 177
 178 static int path_watch_one(Path *p, PathSpec *s) {
 179         static const int flags_table[_PATH_TYPE_MAX] = {
 180                 [PATH_EXISTS] = IN_DELETE_SELF|IN_MOVE_SELF,
 181                 [PATH_CHANGED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO,
 182                 [PATH_DIRECTORY_NOT_EMPTY] = IN_DELETE_SELF|IN_MOVE_SELF|IN_CREATE|IN_MOVED_TO
 183         };
 184
 185         bool exists = false;
 186         char *k;
 187         int r;
 188
 189         assert(p);
 190         assert(s);
 191
 192         path_unwatch_one(p, s);
 193
 194         if (!(k = strdup(s->path)))
 195                 return -ENOMEM;
 196
 197         if ((s->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC)) < 0) {
 198                 r = -errno;
 199                 goto fail;
 200         }
 201
 202         if (unit_watch_fd(UNIT(p), s->inotify_fd, EPOLLIN, &s->watch) < 0) {
 203                 r = -errno;
 204                 goto fail;
 205         }
 206
 207         if ((s->primary_wd = inotify_add_watch(s->inotify_fd, k, flags_table[s->type])) >= 0)
 208                 exists = true;
 209
 210         for (;;) {
 211                 int flags;
 212                 char *slash;
 213
 214                 /* This assumes the path was passed through path_kill_slashes()! */
 215                 if (!(slash = strrchr(k, '/')))
 216                         break;
 217
 218                 *slash = 0;
 219
 220                 flags = IN_DELETE_SELF|IN_MOVE_SELF;
 221                 if (!exists)
 222                         flags |= IN_CREATE | IN_MOVED_TO | IN_ATTRIB;
 223
 224                 if (inotify_add_watch(s->inotify_fd, k, flags) >= 0)
 225                         exists = true;
 226         }
 227
 228         return 0;
 229
 230 fail:
 231         free(k);
 232
 233         path_unwatch_one(p, s);
 234         return r;
 235 }
 236
 237 static void path_unwatch(Path *p) {
 238         PathSpec *s;
 239
 240         assert(p);
 241
 242         LIST_FOREACH(spec, s, p->specs)
 243                 path_unwatch_one(p, s);
 244 }
 245
 246 static int path_watch(Path *p) {
 247         int r;
 248         PathSpec *s;
 249
 250         assert(p);
 251
 252         LIST_FOREACH(spec, s, p->specs)
 253                 if ((r = path_watch_one(p, s)) < 0)
 254                         return r;
 255
 256         return 0;
 257 }
 258
 259 static void path_set_state(Path *p, PathState state) {
 260         PathState old_state;
 261         assert(p);
 262
 263         old_state = p->state;
 264         p->state = state;
 265
 266         if (state != PATH_WAITING)
 267                 path_unwatch(p);
 268
 269         if (state != old_state)
 270                 log_debug("%s changed %s -> %s",
 271                           p->meta.id,
 272                           path_state_to_string(old_state),
 273                           path_state_to_string(state));
 274
 275         unit_notify(UNIT(p), state_translation_table[old_state], state_translation_table[state]);
 276 }
 277
 278 static void path_enter_waiting(Path *p, bool initial);
 279
 280 static int path_coldplug(Unit *u) {
 281         Path *p = PATH(u);
 282
 283         assert(p);
 284         assert(p->state == PATH_DEAD);
 285
 286         if (p->deserialized_state != p->state) {
 287
 288                 if (p->deserialized_state == PATH_WAITING ||
 289                     p->deserialized_state == PATH_RUNNING)
 290                         path_enter_waiting(p, true);
 291                 else
 292                         path_set_state(p, p->deserialized_state);
 293         }
 294
 295         return 0;
 296 }
 297
 298 static void path_enter_dead(Path *p, bool success) {
 299         assert(p);
 300
 301         if (!success)
 302                 p->failure = true;
 303
 304         path_set_state(p, p->failure ? PATH_FAILED : PATH_DEAD);
 305 }
 306
 307 static void path_enter_running(Path *p) {
 308         int r;
 309         DBusError error;
 310
 311         assert(p);
 312         dbus_error_init(&error);
 313
 314         /* Don't start job if we are supposed to go down */
 315         if (p->meta.job && p->meta.job->type == JOB_STOP)
 316                 return;
 317
 318         if ((r = manager_add_job(p->meta.manager, JOB_START, p->unit, JOB_REPLACE, true, &error, NULL)) < 0)
 319                 goto fail;
 320
 321         path_set_state(p, PATH_RUNNING);
 322         return;
 323
 324 fail:
 325         log_warning("%s failed to queue unit startup job: %s", p->meta.id, bus_error(&error, r));
 326         path_enter_dead(p, false);
 327
 328         dbus_error_free(&error);
 329 }
 330
 331
 332 static void path_enter_waiting(Path *p, bool initial) {
 333         PathSpec *s;
 334         int r;
 335         bool good = false;
 336
 337         LIST_FOREACH(spec, s, p->specs) {
 338
 339                 switch (s->type) {
 340
 341                 case PATH_EXISTS:
 342                         good = access(s->path, F_OK) >= 0;
 343                         break;
 344
 345                 case PATH_DIRECTORY_NOT_EMPTY:
 346                         good = dir_is_empty(s->path) == 0;
 347                         break;
 348
 349                 case PATH_CHANGED: {
 350                         bool b;
 351
 352                         b = access(s->path, F_OK) >= 0;
 353                         good = !initial && b != s->previous_exists;
 354                         s->previous_exists = b;
 355                         break;
 356                 }
 357
 358                 default:
 359                         ;
 360                 }
 361
 362                 if (good)
 363                         break;
 364         }
 365
 366         if (good) {
 367                 path_enter_running(p);
 368                 return;
 369         }
 370
 371         if ((r = path_watch(p)) < 0)
 372                 goto fail;
 373
 374         path_set_state(p, PATH_WAITING);
 375         return;
 376
 377 fail:
 378         log_warning("%s failed to enter waiting state: %s", p->meta.id, strerror(-r));
 379         path_enter_dead(p, false);
 380 }
 381
 382 static int path_start(Unit *u) {
 383         Path *p = PATH(u);
 384
 385         assert(p);
 386         assert(p->state == PATH_DEAD || p->state == PATH_FAILED);
 387
 388         if (p->unit->meta.load_state != UNIT_LOADED)
 389                 return -ENOENT;
 390
 391         p->failure = false;
 392 path_enter_waiting(p, true);
 393         return 0;
 394 }
 395
 396 static int path_stop(Unit *u) {
 397         Path *p = PATH(u);
 398
 399         assert(p);
 400         assert(p->state == PATH_WAITING || p->state == PATH_RUNNING);
 401
 402         path_enter_dead(p, true);
 403         return 0;
 404 }
 405
 406 static int path_serialize(Unit *u, FILE *f, FDSet *fds) {
 407         Path *p = PATH(u);
 408
 409         assert(u);
 410         assert(f);
 411         assert(fds);
 412
 413         unit_serialize_item(u, f, "state", path_state_to_string(p->state));
 414
 415         return 0;
 416 }
 417
 418 static int path_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
 419         Path *p = PATH(u);
 420
 421         assert(u);
 422         assert(key);
 423         assert(value);
 424         assert(fds);
 425
 426         if (streq(key, "state")) {
 427                 PathState state;
 428
 429                 if ((state = path_state_from_string(value)) < 0)
 430                         log_debug("Failed to parse state value %s", value);
 431                 else
 432                         p->deserialized_state = state;
 433         } else
 434                 log_debug("Unknown serialization key '%s'", key);
 435
 436         return 0;
 437 }
 438
 439 static UnitActiveState path_active_state(Unit *u) {
 440         assert(u);
 441
 442         return state_translation_table[PATH(u)->state];
 443 }
 444
 445 static const char *path_sub_state_to_string(Unit *u) {
 446         assert(u);
 447
 448         return path_state_to_string(PATH(u)->state);
 449 }
 450
 451 static void path_fd_event(Unit *u, int fd, uint32_t events, Watch *w) {
 452         Path *p = PATH(u);
 453         int l;
 454         ssize_t k;
 455         struct inotify_event *buf = NULL;
 456         PathSpec *s;
 457
 458         assert(p);
 459         assert(fd >= 0);
 460
 461         if (p->state != PATH_WAITING)
 462                 return;
 463
 464         log_debug("inotify wakeup on %s.", u->meta.id);
 465
 466         if (events != EPOLLIN) {
 467                 log_error("Got Invalid poll event on inotify.");
 468                 goto fail;
 469         }
 470
 471         LIST_FOREACH(spec, s, p->specs)
 472                 if (s->inotify_fd == fd)
 473                         break;
 474
 475         if (!s) {
 476                 log_error("Got event on unknown fd.");
 477                 goto fail;
 478         }
 479
 480         if (ioctl(fd, FIONREAD, &l) < 0) {
 481                 log_error("FIONREAD failed: %s", strerror(errno));
 482                 goto fail;
 483         }
 484
 485         if (!(buf = malloc(l))) {
 486                 log_error("Failed to allocate buffer: %s", strerror(-ENOMEM));
 487                 goto fail;
 488         }
 489
 490         if ((k = read(fd, buf, l)) < 0) {
 491                 log_error("Failed to read inotify event: %s", strerror(-errno));
 492                 goto fail;
 493         }
 494
 495         if ((size_t) k < sizeof(struct inotify_event) ||
 496             (size_t) k < sizeof(struct inotify_event) + buf->len) {
 497                 log_error("inotify event too small.");
 498                 goto fail;
 499         }
 500
 501         if (s->type == PATH_CHANGED && s->primary_wd == buf->wd)
 502                 path_enter_running(p);
 503         else
 504                 path_enter_waiting(p, false);
 505
 506         free(buf);
 507
 508         return;
 509
 510 fail:
 511         free(buf);
 512         path_enter_dead(p, false);
 513 }
 514
 515 void path_unit_notify(Unit *u, UnitActiveState new_state) {
 516         char *n;
 517         int r;
 518         Iterator i;
 519
 520         if (u->meta.type == UNIT_PATH)
 521                 return;
 522
 523         SET_FOREACH(n, u->meta.names, i) {
 524                 char *k;
 525                 Unit *t;
 526                 Path *p;
 527
 528                 if (!(k = unit_name_change_suffix(n, ".path"))) {
 529                         r = -ENOMEM;
 530                         goto fail;
 531                 }
 532
 533                 t = manager_get_unit(u->meta.manager, k);
 534                 free(k);
 535
 536                 if (!t)
 537                         continue;
 538
 539                 if (t->meta.load_state != UNIT_LOADED)
 540                         continue;
 541
 542                 p = PATH(t);
 543
 544                 if (p->unit != u)
 545                         continue;
 546
 547                 if (p->state == PATH_RUNNING && new_state == UNIT_INACTIVE) {
 548                         log_debug("%s got notified about unit deactivation.", p->meta.id);
 549                         path_enter_waiting(p, false);
 550                 }
 551         }
 552
 553         return;
 554
 555 fail:
 556         log_error("Failed find path unit: %s", strerror(-r));
 557 }
 558
 559 static void path_reset_failed(Unit *u) {
 560         Path *p = PATH(u);
 561
 562         assert(p);
 563
 564         if (p->state == PATH_FAILED)
 565                 path_set_state(p, PATH_DEAD);
 566
 567         p->failure = false;
 568 }
 569
 570 static const char* const path_state_table[_PATH_STATE_MAX] = {
 571         [PATH_DEAD] = "dead",
 572         [PATH_WAITING] = "waiting",
 573         [PATH_RUNNING] = "running",
 574         [PATH_FAILED] = "failed"
 575 };
 576
 577 DEFINE_STRING_TABLE_LOOKUP(path_state, PathState);
 578
 579 static const char* const path_type_table[_PATH_TYPE_MAX] = {
 580         [PATH_EXISTS] = "PathExists",
 581         [PATH_CHANGED] = "PathChanged",
 582         [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty"
 583 };
 584
 585 DEFINE_STRING_TABLE_LOOKUP(path_type, PathType);
 586
 587 const UnitVTable path_vtable = {
 588         .suffix = ".path",
 589
 590         .done = path_done,
 591         .load = path_load,
 592
 593         .coldplug = path_coldplug,
 594
 595         .dump = path_dump,
 596
 597         .start = path_start,
 598         .stop = path_stop,
 599
 600         .serialize = path_serialize,
 601         .deserialize_item = path_deserialize_item,
 602
 603         .active_state = path_active_state,
 604         .sub_state_to_string = path_sub_state_to_string,
 605
 606         .fd_event = path_fd_event,
 607
 608         .reset_failed = path_reset_failed,
 609
 610         .bus_interface = "org.freedesktop.systemd1.Path",
 611         .bus_message_handler = bus_path_message_handler
 612 };