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