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