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_delete_job(Manager *m, Job *j) {
  55         assert(m);
  56         assert(j);
  57
  58         manager_transaction_unlink_job(m, j);
  59
  60         if (!j->linked)
  61                 job_free(j);
  62 }
  63
  64 static void transaction_abort(Manager *m) {
  65         Job *j;
  66
  67         assert(m);
  68
  69         while ((j = hashmap_first(m->transaction_jobs)))
  70                 if (j->linked)
  71                         transaction_delete_job(m, j);
  72                 else
  73                         job_free(j);
  74
  75         assert(hashmap_isempty(m->transaction_jobs));
  76         assert(!m->transaction_anchor);
  77 }
  78
  79 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
  80         JobDependency *l;
  81
  82         assert(m);
  83
  84         for (l = j ? j->subject_list : m->transaction_anchor; l; l = l->subject_next) {
  85
  86                 /* This link does not matter */
  87                 if (!l->matters)
  88                         continue;
  89
  90                 /* This name has already been marked */
  91                 if (l->object->generation == generation)
  92                         continue;
  93
  94                 l->object->matters_to_anchor = true;
  95                 l->object->generation = generation;
  96
  97                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
  98         }
  99 }
 100
 101 static bool types_match(JobType a, JobType b, JobType c, JobType d) {
 102         return
 103                 (a == c && b == d) ||
 104                 (a == d && b == c);
 105 }
 106
 107 static int types_merge(JobType *a, JobType b) {
 108         if (*a == b)
 109                 return 0;
 110
 111         if (types_match(*a, b, JOB_START, JOB_VERIFY_STARTED))
 112                 *a = JOB_START;
 113         else if (types_match(*a, b, JOB_START, JOB_RELOAD) ||
 114                  types_match(*a, b, JOB_START, JOB_RELOAD_OR_START) ||
 115                  types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD_OR_START) ||
 116                  types_match(*a, b, JOB_RELOAD, JOB_RELOAD_OR_START))
 117                 *a = JOB_RELOAD_OR_START;
 118         else if (types_match(*a, b, JOB_START, JOB_RESTART) ||
 119                  types_match(*a, b, JOB_START, JOB_TRY_RESTART) ||
 120                  types_match(*a, b, JOB_VERIFY_STARTED, JOB_RESTART) ||
 121                  types_match(*a, b, JOB_RELOAD, JOB_RESTART) ||
 122                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_RESTART) ||
 123                  types_match(*a, b, JOB_RELOAD_OR_START, JOB_TRY_RESTART) ||
 124                  types_match(*a, b, JOB_RESTART, JOB_TRY_RESTART))
 125                 *a = JOB_RESTART;
 126         else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_RELOAD))
 127                 *a = JOB_RELOAD;
 128         else if (types_match(*a, b, JOB_VERIFY_STARTED, JOB_TRY_RESTART) ||
 129                  types_match(*a, b, JOB_RELOAD, JOB_TRY_RESTART))
 130                 *a = JOB_TRY_RESTART;
 131
 132         return -EEXIST;
 133 }
 134
 135 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 136         JobDependency *l, *last;
 137
 138         assert(j);
 139         assert(other);
 140         assert(j->name == other->name);
 141         assert(!j->linked);
 142
 143         j->type = t;
 144         j->state = JOB_WAITING;
 145
 146         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 147
 148         /* Patch us in as new owner of the JobDependency objects */
 149         last = NULL;
 150         for (l = other->subject_list; l; l = l->subject_next) {
 151                 assert(l->subject == other);
 152                 l->subject = j;
 153                 last = l;
 154         }
 155
 156         /* Merge both lists */
 157         if (last) {
 158                 last->subject_next = j->subject_list;
 159                 if (j->subject_list)
 160                         j->subject_list->subject_prev = last;
 161                 j->subject_list = other->subject_list;
 162         }
 163
 164         /* Patch us in as new owner of the JobDependency objects */
 165         last = NULL;
 166         for (l = other->object_list; l; l = l->object_next) {
 167                 assert(l->object == other);
 168                 l->object = j;
 169                 last = l;
 170         }
 171
 172         /* Merge both lists */
 173         if (last) {
 174                 last->object_next = j->object_list;
 175                 if (j->object_list)
 176                         j->object_list->object_prev = last;
 177                 j->object_list = other->object_list;
 178         }
 179
 180         /* Kill the other job */
 181         other->subject_list = NULL;
 182         other->object_list = NULL;
 183         transaction_delete_job(m, other);
 184 }
 185
 186 static int transaction_merge_jobs(Manager *m) {
 187         Job *j;
 188         void *state;
 189         int r;
 190
 191         assert(m);
 192
 193         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 194                 JobType t = j->type;
 195                 Job *k;
 196
 197                 for (k = j->transaction_next; k; k = k->transaction_next)
 198                         if ((r = types_merge(&t, k->type)) < 0)
 199                                 return r;
 200
 201                 while ((k = j->transaction_next)) {
 202                         if (j->linked) {
 203                                 transaction_merge_and_delete_job(m, k, j, t);
 204                                 j = k;
 205                         } else
 206                                 transaction_merge_and_delete_job(m, j, k, t);
 207                 }
 208
 209                 assert(!j->transaction_next);
 210                 assert(!j->transaction_prev);
 211         }
 212
 213         return 0;
 214 }
 215
 216 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 217         void *state;
 218         Name *n;
 219         int r;
 220
 221         assert(m);
 222         assert(j);
 223
 224         /* Did we find a cycle? */
 225         if (j->marker && j->generation == generation) {
 226                 Job *k;
 227
 228                 /* So, we already have been here. We have a
 229                  * cycle. Let's try to break it. We go backwards in our
 230                  * path and try to find a suitable job to remove. */
 231
 232                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 233                         if (!k->matters_to_anchor) {
 234                                 log_debug("Breaking order cycle by deleting job %s", name_id(k->name));
 235                                 transaction_delete_job(m, k);
 236                                 return -EAGAIN;
 237                         }
 238
 239                         /* Check if this in fact was the beginning of
 240                          * the cycle */
 241                         if (k == j)
 242                                 break;
 243                 }
 244
 245                 return -ELOOP;
 246         }
 247
 248         j->marker = from;
 249         j->generation = generation;
 250
 251         /* We assume that the the dependencies are both-ways, and
 252          * hence can ignore NAME_AFTER */
 253
 254         SET_FOREACH(n, j->name->meta.dependencies[NAME_BEFORE], state) {
 255                 Job *o;
 256
 257                 if (!(o = hashmap_get(m->transaction_jobs, n)))
 258                         if (!(o = n->meta.job))
 259                                 continue;
 260
 261                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 262                         return r;
 263         }
 264
 265         return 0;
 266 }
 267
 268 static int transaction_verify_order(Manager *m, unsigned *generation) {
 269         bool again;
 270         assert(m);
 271         assert(generation);
 272
 273         do {
 274                 Job *j;
 275                 int r;
 276                 void *state;
 277
 278                 again = false;
 279
 280                 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 281
 282                         /* Assume merged */
 283                         assert(!j->transaction_next);
 284                         assert(!j->transaction_prev);
 285
 286                         if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)  {
 287
 288                                 /* There was a cycleq, but it was fixed,
 289                                  * we need to restart our algorithm */
 290                                 if (r == -EAGAIN) {
 291                                         again = true;
 292                                         break;
 293                                 }
 294
 295                                 return r;
 296                         }
 297                 }
 298         } while (again);
 299
 300         return 0;
 301 }
 302
 303 static void transaction_collect_garbage(Manager *m) {
 304         bool again;
 305
 306         assert(m);
 307
 308         do {
 309                 void *state;
 310                 Job *j;
 311
 312                 again = false;
 313
 314                 HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 315                         if (j->object_list)
 316                                 continue;
 317
 318                         log_debug("Garbage collecting job %s", name_id(j->name));
 319
 320                         transaction_delete_job(m, j);
 321                         again = true;
 322                         break;
 323                 }
 324
 325         } while (again);
 326 }
 327
 328 static int transaction_is_destructive(Manager *m, JobMode mode) {
 329         void *state;
 330         Job *j;
 331
 332         assert(m);
 333
 334         /* Checks whether applying this transaction means that
 335          * existing jobs would be replaced */
 336
 337         HASHMAP_FOREACH(j, m->transaction_jobs, state)
 338                 if (j->name->meta.job && j->name->meta.job != j)
 339                         return -EEXIST;
 340
 341         return 0;
 342 }
 343
 344 static int transaction_apply(Manager *m, JobMode mode) {
 345         void *state;
 346         Job *j;
 347         int r;
 348
 349         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 350                 if (j->linked)
 351                         continue;
 352
 353                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 354                         goto rollback;
 355         }
 356
 357         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 358                 if (j->linked)
 359                         continue;
 360
 361                 if (j->name->meta.job)
 362                         job_free(j->name->meta.job);
 363
 364                 j->name->meta.job = j;
 365                 j->linked = true;
 366
 367                 /* We're fully installed. Now let's free data we don't
 368                  * need anymore. */
 369
 370                 assert(!j->transaction_next);
 371                 assert(!j->transaction_prev);
 372
 373                 while (j->subject_list)
 374                         job_dependency_free(j->subject_list);
 375                 while (j->object_list)
 376                         job_dependency_free(j->object_list);
 377         }
 378
 379         return 0;
 380
 381 rollback:
 382
 383         HASHMAP_FOREACH(j, m->transaction_jobs, state) {
 384                 if (j->linked)
 385                         continue;
 386
 387                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
 388         }
 389
 390         return r;
 391 }
 392
 393
 394 static int transaction_activate(Manager *m, JobMode mode) {
 395         int r;
 396         unsigned generation = 1;
 397
 398         assert(m);
 399
 400         /* This applies the changes recorded in transaction_jobs to
 401          * the actual list of jobs, if possible. */
 402
 403         /* First step: figure out which jobs matter */
 404         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
 405
 406         /* Second step: let's merge entries we can merge */
 407         if ((r = transaction_merge_jobs(m)) < 0)
 408                 goto rollback;
 409
 410         /* Third step: verify order makes sense */
 411         if ((r = transaction_verify_order(m, &generation)) < 0)
 412                 goto rollback;
 413
 414         /* Third step: do garbage colletion */
 415         transaction_collect_garbage(m);
 416
 417         /* Fourth step: check whether we can actually apply this */
 418         if (mode == JOB_FAIL)
 419                 if ((r = transaction_is_destructive(m, mode)) < 0)
 420                         goto rollback;
 421
 422         /* Fifth step: apply changes */
 423         if ((r = transaction_apply(m, mode)) < 0)
 424                 goto rollback;
 425
 426         assert(hashmap_isempty(m->transaction_jobs));
 427         assert(!m->transaction_anchor);
 428
 429         return 0;
 430
 431 rollback:
 432         transaction_abort(m);
 433         return r;
 434 }
 435
 436 static Job* transaction_add_one_job(Manager *m, JobType type, Name *name, bool *is_new) {
 437         Job *j, *f;
 438         int r;
 439
 440         assert(m);
 441         assert(name);
 442
 443         /* Looks for an axisting prospective job and returns that. If
 444          * it doesn't exist it is created and added to the prospective
 445          * jobs list. */
 446
 447         f = hashmap_get(m->transaction_jobs, name);
 448
 449         for (j = f; j; j = j->transaction_next) {
 450                 assert(j->name == name);
 451
 452                 if (j->type == type) {
 453                         if (is_new)
 454                                 *is_new = false;
 455                         return j;
 456                 }
 457         }
 458
 459         if (name->meta.job && name->meta.job->type == type)
 460                 j = name->meta.job;
 461         else if (!(j = job_new(m, type, name)))
 462                 return NULL;
 463
 464         if ((r = hashmap_replace(m->transaction_jobs, name, j)) < 0) {
 465                 job_free(j);
 466                 return NULL;
 467         }
 468
 469         j->transaction_next = f;
 470
 471         if (f)
 472                 f->transaction_prev = j;
 473
 474         j->generation = 0;
 475         j->marker = NULL;
 476         j->matters_to_anchor = false;
 477
 478         if (is_new)
 479                 *is_new = true;
 480
 481         return j;
 482 }
 483
 484 void manager_transaction_unlink_job(Manager *m, Job *j) {
 485         assert(m);
 486         assert(j);
 487
 488         if (j->transaction_prev)
 489                 j->transaction_prev->transaction_next = j->transaction_next;
 490         else if (j->transaction_next)
 491                 hashmap_replace(m->transaction_jobs, j->name, j->transaction_next);
 492         else
 493                 hashmap_remove_value(m->transaction_jobs, j->name, j);
 494
 495         if (j->transaction_next)
 496                 j->transaction_next->transaction_prev = j->transaction_prev;
 497
 498         j->transaction_prev = j->transaction_next = NULL;
 499
 500         while (j->subject_list)
 501                 job_dependency_free(j->subject_list);
 502
 503         while (j->object_list) {
 504                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
 505
 506                 job_dependency_free(j->object_list);
 507
 508                 if (other) {
 509                         log_debug("Deleting job %s as dependency of job %s", name_id(other->name), name_id(j->name));
 510                         transaction_delete_job(m, other);
 511                 }
 512         }
 513 }
 514
 515 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Name *name, Job *by, bool matters, bool force, Job **_ret) {
 516         Job *ret;
 517         void *state;
 518         Name *dep;
 519         int r;
 520         bool is_new;
 521
 522         assert(m);
 523         assert(type < _JOB_TYPE_MAX);
 524         assert(name);
 525
 526         if (name->meta.state != NAME_LOADED)
 527                 return -EINVAL;
 528
 529         /* First add the job. */
 530         if (!(ret = transaction_add_one_job(m, type, name, &is_new)))
 531                 return -ENOMEM;
 532
 533         /* Then, add a link to the job. */
 534         if (!job_dependency_new(by, ret, matters))
 535                 return -ENOMEM;
 536
 537         if (is_new) {
 538                 /* Finally, recursively add in all dependencies. */
 539                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
 540                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRES], state)
 541                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0)
 542                                         goto fail;
 543                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUIRES], state)
 544                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0)
 545                                         goto fail;
 546                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_WANTS], state)
 547                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0)
 548                                         goto fail;
 549                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUISITE], state)
 550                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, true, force, NULL)) < 0)
 551                                         goto fail;
 552                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_SOFT_REQUISITE], state)
 553                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_STARTED, dep, ret, !force, force, NULL)) < 0)
 554                                         goto fail;
 555                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_CONFLICTS], state)
 556                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0)
 557                                         goto fail;
 558
 559                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
 560
 561                         SET_FOREACH(dep, ret->name->meta.dependencies[NAME_REQUIRED_BY], state)
 562                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0)
 563                                         goto fail;
 564                 }
 565
 566                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
 567         }
 568
 569         return 0;
 570
 571 fail:
 572         return r;
 573 }
 574
 575 int manager_add_job(Manager *m, JobType type, Name *name, JobMode mode, bool force, Job **_ret) {
 576         int r;
 577         Job *ret;
 578
 579         assert(m);
 580         assert(type < _JOB_TYPE_MAX);
 581         assert(name);
 582         assert(mode < _JOB_MODE_MAX);
 583
 584         if ((r = transaction_add_job_and_dependencies(m, type, name, NULL, true, force, &ret))) {
 585                 transaction_abort(m);
 586                 return r;
 587         }
 588
 589         if ((r = transaction_activate(m, mode)) < 0)
 590                 return r;
 591
 592         if (_ret)
 593                 *_ret = ret;
 594
 595         return 0;
 596 }
 597
 598 Job *manager_get_job(Manager *m, uint32_t id) {
 599         assert(m);
 600
 601         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
 602 }
 603
 604 Name *manager_get_name(Manager *m, const char *name) {
 605         assert(m);
 606         assert(name);
 607
 608         return hashmap_get(m->names, name);
 609 }
 610
 611 static int dispatch_load_queue(Manager *m) {
 612         Meta *meta;
 613
 614         assert(m);
 615
 616         /* Make sure we are not run recursively */
 617         if (m->dispatching_load_queue)
 618                 return 0;
 619
 620         m->dispatching_load_queue = true;
 621
 622         /* Dispatches the load queue. Takes a name from the queue and
 623          * tries to load its data until the queue is empty */
 624
 625         while ((meta = m->load_queue)) {
 626                 name_load(NAME(meta));
 627                 LIST_REMOVE(Meta, m->load_queue, meta);
 628         }
 629
 630         m->dispatching_load_queue = false;
 631
 632         return 0;
 633 }
 634
 635 int manager_load_name(Manager *m, const char *name, Name **_ret) {
 636         Name *ret;
 637         NameType t;
 638         int r;
 639         char *n;
 640
 641         assert(m);
 642         assert(name);
 643         assert(_ret);
 644
 645         if (!name_is_valid(name))
 646                 return -EINVAL;
 647
 648         /* This will load the service information files, but not actually
 649          * start any services or anything */
 650
 651         if ((ret = manager_get_name(m, name)))
 652                 goto finish;
 653
 654         if ((t = name_type_from_string(name)) == _NAME_TYPE_INVALID)
 655                 return -EINVAL;
 656
 657         if (!(ret = name_new(m)))
 658                 return -ENOMEM;
 659
 660         ret->meta.type = t;
 661
 662         if (!(n = strdup(name))) {
 663                 name_free(ret);
 664                 return -ENOMEM;
 665         }
 666
 667         if (set_put(ret->meta.names, n) < 0) {
 668                 name_free(ret);
 669                 free(n);
 670                 return -ENOMEM;
 671         }
 672
 673         if ((r = name_link(ret)) < 0) {
 674                 name_free(ret);
 675                 return r;
 676         }
 677
 678         /* At this point the new entry is created and linked. However,
 679          * not loaded. Now load this entry and all its dependencies
 680          * recursively */
 681
 682         dispatch_load_queue(m);
 683
 684 finish:
 685
 686         *_ret = ret;
 687         return 0;
 688 }
 689
 690 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
 691         void *state;
 692         Job *j;
 693
 694         assert(s);
 695         assert(f);
 696
 697         HASHMAP_FOREACH(j, s->jobs, state)
 698                 job_dump(j, f, prefix);
 699 }
 700
 701 void manager_dump_names(Manager *s, FILE *f, const char *prefix) {
 702         void *state;
 703         Name *n;
 704         const char *t;
 705
 706         assert(s);
 707         assert(f);
 708
 709         HASHMAP_FOREACH_KEY(n, t, s->names, state)
 710                 if (name_id(n) == t)
 711                         name_dump(n, f, prefix);
 712 }
 713
 714 void manager_clear_jobs(Manager *m) {
 715         Job *j;
 716
 717         assert(m);
 718
 719         transaction_abort(m);
 720
 721         while ((j = hashmap_first(m->jobs)))
 722                 job_free(j);
 723 }