manager.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #include <assert.h>
   4 #include <errno.h>
   5 #include <string.h>
   6
   7 #include "manager.h"
   8 #include "hashmap.h"
   9 #include "macro.h"
  10 #include "strv.h"
  11 #include "log.h"
  12
  13 Manager* manager_new(void) {
  14         Manager *m;
  15
  16         if (!(m = new0(Manager, 1)))
  17                 return NULL;
  18
  19         if (!(m->names = hashmap_new(string_hash_func, string_compare_func)))
  20                 goto fail;
  21
  22         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  23                 goto fail;
  24
  25         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
  26                 goto fail;
  27
  28         return m;
  29
  30 fail:
  31         manager_free(m);
  32         return NULL;
  33 }
  34
  35 void manager_free(Manager *m) {
  36         Name *n;
  37         Job *j;
  38
  39         assert(m);
  40
  41         while ((n = hashmap_first(m->names)))
  42                 name_free(n);
  43
  44         while ((j = hashmap_steal_first(m->transaction_jobs)))
  45                 job_free(j);
  46
  47         hashmap_free(m->names);
  48         hashmap_free(m->jobs);
  49         hashmap_free(m->transaction_jobs);
  50
  51         free(m);
  52 }
  53
  54 static void transaction_abort(Manager *m) {
  55         Job *j;
  56
  57         assert(m);
  58
  59         while ((j = hashmap_first(m->transaction_jobs)))
  60                 if (j->linked)
  61                         manager_transaction_delete_job(m, j);
  62                 else
  63                         job_free(j);
  64
  65         assert(hashmap_isempty(m->transaction_jobs));
  66         assert(!m->transaction_anchor);
  67 }
  68
  69 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
  70         JobDependency *l;
  71
  72         assert(m);
  73
  74         for (l = j ? j->subject_list : m->transaction_anchor; l; l = l->subject_next) {
  75
  76                 /* This link does not matter */
  77                 if (!l->matters)
  78                         continue;
  79
  80                 /* This name has already been marked */
  81                 if (l->object->generation == generation)
  82                         continue;
  83
  84                 l->object->matters_to_anchor = true;
  85                 l->object->generation = generation;
  86
  87                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
  88         }
  89 }
  90
  91 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
  92         return
  93                 (a == c && b == d) ||
  94                 (a == d && b == c);
  95 }
  96
  97 static int types_merge(JobType *a, JobType b) {
  98         if (*a == b)
  99                 return 0;
 100
 101         if (types_match(*a, b, JOB_START, JOB_VERIFY_STARTED))
 102                 *a = JOB_START;
 103         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
 104                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
 105                  types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD_OR_START) ||
 106                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
 107                 *a = JOB_RELOAD_OR_START;
 108         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
 109                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
 110                  types_match(*a, b, JOB_VERIFY_STARTED, JOB_RESTART) ||
 111                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
 112                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
 113                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
 114                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
 115                 *a = JOB_RESTART;
 116         else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD))
 117                 *a = JOB_RELOAD;
 118         else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_TRY_RESTART) ||
 119                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
 120                 *a = JOB_TRY_RESTART;
 121
 122         return -EEXIST;
 123 }
 124
 125 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 126         JobDependency *l, *last;
 127
 128         assert(j);
 129         assert(other);
 130         assert(j->name == other->name);
 131         assert(!j->linked);
 132
 133         j->type = t;
 134         j->state = JOB_WAITING;
 135
 136         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 137
 138         /* Patch us in as new owner of the JobDependency objects */
 139         last = NULL;
 140         for (l = other->subject_list; l; l = l->subject_next) {
 141                 assert(l->subject == other);
 142                 l->subject = j;
 143                 last = l;
 144         }
 145
 146         /* Merge both lists */
 147         if (last) {
 148                 last->subject_next = j->subject_list;
 149                 if (j->subject_list)
 150                         j->subject_list->subject_prev = last;
 151                 j->subject_list = other->subject_list;
 152         }
 153
 154         /* Patch us in as new owner of the JobDependency objects */
 155         last = NULL;
 156         for (l = other->object_list; l; l = l->object_next) {
 157                 assert(l->object == other);
 158                 l->object = j;
 159                 last = l;
 160         }
 161
 162         /* Merge both lists */
 163         if (last) {
 164                 last->object_next = j->object_list;
 165                 if (j->object_list)
 166                         j->object_list->object_prev = last;
 167                 j->object_list = other->object_list;
 168         }
 169
 170         /* Kill the other job */
 171         other->subject_list = NULL;
 172         other->object_list = NULL;
 173         manager_transaction_delete_job(m, other);
 174 }
 175
 176 static int transaction_merge_jobs(Manager *m) {
 177         Job *j;
 178         void *state;
 179         int r;
 180
 181         assert(m);
 182
 183         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 184                 JobType t = j->type;
 185                 Job *k;
 186
 187                 for (k = j->transaction_next; k; k = k->transaction_next)
 188                         if ((r = types_merge(&t, k->type)) < 0)
 189                                 return r;
 190
 191                 while ((k = j->transaction_next)) {
 192                         if (j->linked) {
 193                                 transaction_merge_and_delete_job(m, k, j, t);
 194                                 j = k;
 195                         } else
 196                                 transaction_merge_and_delete_job(m, j, k, t);
 197                 }
 198
 199                 assert(!j->transaction_next);
 200                 assert(!j->transaction_prev);
 201         }
 202
 203         return 0;
 204 }
 205
 206 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 207         void *state;
 208         Name *n;
 209         int r;
 210
 211         assert(m);
 212         assert(j);
 213
 214         /* Did we find a cycle? */
 215         if (j->marker && j->generation == generation) {
 216                 Job *k;
 217
 218                 /* So, we already have been here. We have a
 219                  * cycle. Let's try to break it. We go backwards in our
 220                  * path and try to find a suitable job to remove. */
 221
 222                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 223                         if (!k->matters_to_anchor) {
 224                                 log_debug("Breaking order cycle by deleting job %s", name_id(k->name));
 225                                 manager_transaction_delete_job(m, k);
 226                                 return -EAGAIN;
 227                         }
 228
 229                         /* Check if this in fact was the beginning of
 230                          * the cycle */
 231                         if (k == j)
 232                                 break;
 233                 }
 234
 235                 return -ELOOP;
 236         }
 237
 238         j->marker = from;
 239         j->generation = generation;
 240
 241         /* We assume that the the dependencies are both-ways, and
 242          * hence can ignore NAME_AFTER */
 243
 244         SET_FOREACH(n, j->name->meta.dependencies[NAME_BEFORE], state) {
 245                 Job *o;
 246
 247                 if (!(o = hashmap_get(m->transaction_jobs, n)))
 248                         if (!(o = n->meta.job))
 249                                 continue;
 250
 251                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 252                         return r;
 253         }
 254
 255         return 0;
 256 }
 257
 258 static int transaction_verify_order(Manager *m, unsigned *generation) {
 259         bool again;
 260         assert(m);
 261         assert(generation);
 262
 263         do {
 264                 Job *j;
 265                 int r;
 266                 void *state;
 267
 268                 again = false;
 269
 270                 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 271
 272                         /* Assume merged */
 273                         assert(!j->transaction_next);
 274                         assert(!j->transaction_prev);
 275
 276                         if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)  {
 277
 278                                 /* There was a cycleq, but it was fixed,
 279                                  * we need to restart our algorithm */
 280                                 if (r == -EAGAIN) {
 281                                         again = true;
 282                                         break;
 283                                 }
 284
 285                                 return r;
 286                         }
 287                 }
 288         } while (again);
 289
 290         return 0;
 291 }
 292
 293 static void transaction_collect_garbage(Manager *m) {
 294         bool again;
 295
 296         assert(m);
 297
 298         do {
 299                 void *state;
 300                 Job *j;
 301
 302                 again = false;
 303
 304                 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 305                         if (j->object_list)
 306                                 continue;
 307
 308                         manager_transaction_delete_job(m, j);
 309                         again = true;
 310                         break;
 311                 }
 312
 313         } while (again);
 314 }
 315
 316 static int transaction_is_destructive(Manager *m, JobMode mode) {
 317         void *state;
 318         Job *j;
 319
 320         assert(m);
 321
 322         /* Checks whether applying this transaction means that
 323          * existing jobs would be replaced */
 324
 325         HASHMAP_FOREACH(j, m->transaction_jobs, state)
 326                 if (j->name->meta.job && j->name->meta.job != j)
 327                         return -EEXIST;
 328
 329         return 0;
 330 }
 331
 332 static int transaction_apply(Manager *m, JobMode mode) {
 333         void *state;
 334         Job *j;
 335         int r;
 336
 337         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 338                 if (j->linked)
 339                         continue;
 340
 341                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 342                         goto rollback;
 343         }
 344
 345         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 346                 if (j->linked)
 347                         continue;
 348
 349                 if (j->name->meta.job)
 350                         job_free(j->name->meta.job);
 351
 352                 j->name->meta.job = j;
 353                 j->linked = true;
 354
 355                 /* We're fully installed. Now let's free data we don't
 356                  * need anymore. */
 357
 358                 assert(!j->transaction_next);
 359                 assert(!j->transaction_prev);
 360
 361                 while (j->subject_list)
 362                         job_dependency_free(j->subject_list);
 363                 while (j->object_list)
 364                         job_dependency_free(j->object_list);
 365         }
 366
 367         return 0;
 368
 369 rollback:
 370
 371         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 372                 if (j->linked)
 373                         continue;
 374
 375                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 376         }
 377
 378         return r;
 379 }
 380
 381
 382 static int transaction_activate(Manager *m, JobMode mode) {
 383         int r;
 384         unsigned generation = 1;
 385
 386         assert(m);
 387
 388         /* This applies the changes recorded in transaction_jobs to
 389          * the actual list of jobs, if possible. */
 390
 391         /* First step: figure out which jobs matter */
 392         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 393
 394         /* Second step: let's merge entries we can merge */
 395         if ((r = transaction_merge_jobs(m)) < 0)
 396                 goto rollback;
 397
 398         /* Third step: verify order makes sense */
 399         if ((r = transaction_verify_order(m, &generation)) < 0)
 400                 goto rollback;
 401
 402         /* Third step: do garbage colletion */
 403         transaction_collect_garbage(m);
 404
 405         /* Fourth step: check whether we can actually apply this */
 406         if (mode == JOB_FAIL)
 407                 if ((r = transaction_is_destructive(m, mode)) < 0)
 408                         goto rollback;
 409
 410         /* Fifth step: apply changes */
 411         if ((r = transaction_apply(m, mode)) < 0)
 412                 goto rollback;
 413
 414         assert(hashmap_isempty(m->transaction_jobs));
 415         assert(!m->transaction_anchor);
 416
 417         return 0;
 418
 419 rollback:
 420         transaction_abort(m);
 421         return r;
 422 }
 423
 424 static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool *is_new) {
 425         Job *j, *f;
 426         int r;
 427
 428         assert(m);
 429         assert(name);
 430
 431         /* Looks for an axisting prospective job and returns that. If
 432          * it doesn't exist it is created and added to the prospective
 433          * jobs list. */
 434
 435         f = hashmap_get(m->transaction_jobs, name);
 436
 437         for (j = f; j; j = j->transaction_next) {
 438                 assert(j->name == name);
 439
 440                 if (j->type == type) {
 441                         if (is_new)
 442                                 *is_new = false;
 443                         return j;
 444                 }
 445         }
 446
 447         if (name->meta.job && name->meta.job->type == type)
 448                 j = name->meta.job;
 449         else if (!(j = job_new(m, type, name)))
 450                 return NULL;
 451
 452         if ((r = hashmap_replace(m->transaction_jobs, name, j)) < 0) {
 453                 job_free(j);
 454                 return NULL;
 455         }
 456
 457         j->transaction_next = f;
 458
 459         if (f)
 460                 f->transaction_prev = j;
 461
 462         j->generation = 0;
 463         j->marker = NULL;
 464         j->matters_to_anchor = false;
 465
 466         if (is_new)
 467                 *is_new = true;
 468
 469         return j;
 470 }
 471
 472 void manager_transaction_delete_job(Manager *m, Job *j) {
 473         assert(m);
 474         assert(j);
 475
 476         if (j->transaction_prev)
 477                 j->transaction_prev->transaction_next = j->transaction_next;
 478         else if (j->transaction_next)
 479                 hashmap_replace(m->transaction_jobs, j->name, j->transaction_next);
 480         else
 481                 hashmap_remove_value(m->transaction_jobs, j->name, j);
 482
 483         if (j->transaction_next)
 484                 j->transaction_next->transaction_prev = j->transaction_prev;
 485
 486         j->transaction_prev = j->transaction_next = NULL;
 487
 488         while (j->subject_list)
 489                 job_dependency_free(j->subject_list);
 490
 491         while (j->object_list) {
 492                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 493
 494                 job_dependency_free(j->object_list);
 495
 496                 if (other) {
 497                         log_debug("Deleting job %s, as dependency of job %s", name_id(j->name), name_id(other->name));
 498                         manager_transaction_delete_job(m, other);
 499                 }
 500         }
 501 }
 502
 503 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name *name, Job *by, bool matters, bool force, Job **_ret) {
 504         Job *ret;
 505         void *state;
 506         Name *dep;
 507         int r;
 508         bool is_new;
 509
 510         assert(m);
 511         assert(type < _JOB_TYPE_MAX);
 512         assert(name);
 513
 514         if (name->meta.state != NAME_LOADED)
 515                 return -EINVAL;
 516
 517         /* First add the job. */
 518         if (!(ret = transaction_add_one_job(m, type, name, &is_new)))
 519                 return -ENOMEM;
 520
 521         /* Then, add a link to the job. */
 522         if (!job_dependency_new(by, ret, matters))
 523                 return -ENOMEM;
 524
 525         if (is_new) {
 526                 /* Finally, recursively add in all dependencies. */
 527                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 528                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRES], state)
 529                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0)
 530                                         goto fail;
 531                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUIRES], state)
 532                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0)
 533                                         goto fail;
 534                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_WANTS], state)
 535                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0)
 536                                         goto fail;
 537                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUISITE], state)
 538                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, true, force, NULL)) < 0)
 539                                         goto fail;
 540                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUISITE], state)
 541                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, !force, force, NULL)) < 0)
 542                                         goto fail;
 543                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_CONFLICTS], state)
 544                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0)
 545                                         goto fail;
 546
 547                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 548
 549                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRED_BY], state)
 550                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0)
 551                                         goto fail;
 552                 }
 553
 554                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 555         }
 556
 557         return 0;
 558
 559 fail:
 560         return r;
 561 }
 562
 563 int manager_add_job(Manager *m, JobType type, Name *name, JobMode mode, bool force, Job **_ret) {
 564         int r;
 565         Job *ret;
 566
 567         assert(m);
 568         assert(type < _JOB_TYPE_MAX);
 569         assert(name);
 570         assert(mode < _JOB_MODE_MAX);
 571
 572         if ((r = transaction_add_job_and_dependencies(m, type, name, NULL, true, force, &ret))) {
 573                 transaction_abort(m);
 574                 return r;
 575         }
 576
 577         if ((r = transaction_activate(m, mode)) < 0)
 578                 return r;
 579
 580         if (_ret)
 581                 *_ret = ret;
 582
 583         return 0;
 584 }
 585
 586 Job *manager_get_job(Manager *m, uint32_t id) {
 587         assert(m);
 588
 589         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 590 }
 591
 592 Name *manager_get_name(Manager *m, const char *name) {
 593         assert(m);
 594         assert(name);
 595
 596         return hashmap_get(m->names, name);
 597 }
 598
 599 static int dispatch_load_queue(Manager *m) {
 600         Meta *meta;
 601
 602         assert(m);
 603
 604         /* Make sure we are not run recursively */
 605         if (m->dispatching_load_queue)
 606                 return 0;
 607
 608         m->dispatching_load_queue = true;
 609
 610         /* Dispatches the load queue. Takes a name from the queue and
 611          * tries to load its data until the queue is empty */
 612
 613         while ((meta = m->load_queue)) {
 614                 name_load(NAME(meta));
 615                 LIST_REMOVE(Meta, m->load_queue, meta);
 616         }
 617
 618         m->dispatching_load_queue = false;
 619
 620         return 0;
 621 }
 622
 623 int manager_load_name(Manager *m, const char *name, Name **_ret) {
 624         Name *ret;
 625         NameType t;
 626         int r;
 627         char *n;
 628
 629         assert(m);
 630         assert(name);
 631         assert(_ret);
 632
 633         if (!name_is_valid(name))
 634                 return -EINVAL;
 635
 636         /* This will load the service information files, but not actually
 637          * start any services or anything */
 638
 639         if ((ret = manager_get_name(m, name)))
 640                 goto finish;
 641
 642         if ((t = name_type_from_string(name)) == _NAME_TYPE_INVALID)
 643                 return -EINVAL;
 644
 645         if (!(ret = name_new(m)))
 646                 return -ENOMEM;
 647
 648         ret->meta.type = t;
 649
 650         if (!(n = strdup(name))) {
 651                 name_free(ret);
 652                 return -ENOMEM;
 653         }
 654
 655         if (set_put(ret->meta.names, n) < 0) {
 656                 name_free(ret);
 657                 free(n);
 658                 return -ENOMEM;
 659         }
 660
 661         if ((r = name_link(ret)) < 0) {
 662                 name_free(ret);
 663                 return r;
 664         }
 665
 666         /* At this point the new entry is created and linked. However,
 667          * not loaded. Now load this entry and all its dependencies
 668          * recursively */
 669
 670         dispatch_load_queue(m);
 671
 672 finish:
 673
 674         *_ret = ret;
 675         return 0;
 676 }
 677
 678 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
 679         void *state;
 680         Job *j;
 681
 682         assert(s);
 683         assert(f);
 684
 685         HASHMAP_FOREACH(j, s->jobs, state)
 686                 job_dump(j, f, prefix);
 687 }
 688
 689 void manager_dump_names(Manager *s, FILE *f, const char *prefix) {
 690         void *state;
 691         Name *n;
 692         const char *t;
 693
 694         assert(s);
 695         assert(f);
 696
 697         HASHMAP_FOREACH_KEY(n, t, s->names, state)
 698                 if (name_id(n) == t)
 699                         name_dump(n, f, prefix);
 700 }
 701
 702 void manager_clear_jobs(Manager *m) {
 703         Job *j;
 704
 705         assert(m);
 706
 707         transaction_abort(m);
 708
 709         while ((j = hashmap_first(m->jobs)))
 710                 job_free(j);
 711 }