manager.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 <assert.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <sys/epoll.h>
  26 #include <signal.h>
  27 #include <sys/signalfd.h>
  28 #include <sys/wait.h>
  29 #include <unistd.h>
  30 #include <utmpx.h>
  31 #include <sys/poll.h>
  32 #include <sys/reboot.h>
  33 #include <sys/ioctl.h>
  34 #include <linux/kd.h>
  35 #include <libcgroup.h>
  36 #include <termios.h>
  37 #include <fcntl.h>
  38
  39 #include "manager.h"
  40 #include "hashmap.h"
  41 #include "macro.h"
  42 #include "strv.h"
  43 #include "log.h"
  44 #include "util.h"
  45 #include "ratelimit.h"
  46 #include "cgroup.h"
  47 #include "mount-setup.h"
  48 #include "utmp-wtmp.h"
  49
  50 static int enable_special_signals(Manager *m) {
  51         char fd;
  52
  53         assert(m);
  54
  55         /* Enable that we get SIGINT on control-alt-del */
  56         if (reboot(RB_DISABLE_CAD) < 0)
  57                 log_warning("Failed to enable ctrl-alt-del handling: %m");
  58
  59         if ((fd = open_terminal("/dev/tty0", O_RDWR)) < 0)
  60                 log_warning("Failed to open /dev/tty0: %m");
  61         else {
  62                 /* Enable that we get SIGWINCH on kbrequest */
  63                 if (ioctl(fd, KDSIGACCEPT, SIGWINCH) < 0)
  64                         log_warning("Failed to enable kbrequest handling: %s", strerror(errno));
  65
  66                 close_nointr_nofail(fd);
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int manager_setup_signals(Manager *m) {
  73         sigset_t mask;
  74         struct epoll_event ev;
  75         struct sigaction sa;
  76
  77         assert(m);
  78
  79         /* We are not interested in SIGSTOP and friends. */
  80         zero(sa);
  81         sa.sa_handler = SIG_DFL;
  82         sa.sa_flags = SA_NOCLDSTOP|SA_RESTART;
  83         assert_se(sigaction(SIGCHLD, &sa, NULL) == 0);
  84
  85         assert_se(sigemptyset(&mask) == 0);
  86         assert_se(sigaddset(&mask, SIGCHLD) == 0);
  87         assert_se(sigaddset(&mask, SIGINT) == 0);   /* Kernel sends us this on control-alt-del */
  88         assert_se(sigaddset(&mask, SIGWINCH) == 0); /* Kernel sends us this on kbrequest (alt-arrowup) */
  89         assert_se(sigaddset(&mask, SIGTERM) == 0);
  90         assert_se(sigaddset(&mask, SIGHUP) == 0);
  91         assert_se(sigaddset(&mask, SIGUSR1) == 0);
  92         assert_se(sigaddset(&mask, SIGUSR2) == 0);
  93         assert_se(sigaddset(&mask, SIGPWR) == 0);
  94         assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
  95
  96         m->signal_watch.type = WATCH_SIGNAL;
  97         if ((m->signal_watch.fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0)
  98                 return -errno;
  99
 100         zero(ev);
 101         ev.events = EPOLLIN;
 102         ev.data.ptr = &m->signal_watch;
 103
 104         if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->signal_watch.fd, &ev) < 0)
 105                 return -errno;
 106
 107         if (m->running_as == MANAGER_INIT)
 108                 return enable_special_signals(m);
 109
 110         return 0;
 111 }
 112
 113 static char** session_dirs(void) {
 114         const char *home, *e;
 115         char *config_home = NULL, *data_home = NULL;
 116         char **config_dirs = NULL, **data_dirs = NULL;
 117         char **r = NULL, **t;
 118
 119         /* Implement the mechanisms defined in
 120          *
 121          * http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html
 122          *
 123          * We look in both the config and the data dirs because we
 124          * want to encourage that distributors ship their unit files
 125          * as data, and allow overriding as configuration.
 126          */
 127
 128         home = getenv("HOME");
 129
 130         if ((e = getenv("XDG_CONFIG_HOME"))) {
 131                 if (asprintf(&config_home, "%s/systemd/session", e) < 0)
 132                         goto fail;
 133
 134         } else if (home) {
 135                 if (asprintf(&config_home, "%s/.config/systemd/session", home) < 0)
 136                         goto fail;
 137         }
 138
 139         if ((e = getenv("XDG_CONFIG_DIRS")))
 140                 config_dirs = strv_split(e, ":");
 141         else
 142                 config_dirs = strv_new("/etc/xdg", NULL);
 143
 144         if (!config_dirs)
 145                 goto fail;
 146
 147         if ((e = getenv("XDG_DATA_HOME"))) {
 148                 if (asprintf(&data_home, "%s/systemd/session", e) < 0)
 149                         goto fail;
 150
 151         } else if (home) {
 152                 if (asprintf(&data_home, "%s/.local/share/systemd/session", home) < 0)
 153                         goto fail;
 154         }
 155
 156         if ((e = getenv("XDG_DATA_DIRS")))
 157                 data_dirs = strv_split(e, ":");
 158         else
 159                 data_dirs = strv_new("/usr/local/share", "/usr/share", NULL);
 160
 161         if (!data_dirs)
 162                 goto fail;
 163
 164         /* Now merge everything we found. */
 165         if (config_home) {
 166                 if (!(t = strv_append(r, config_home)))
 167                         goto fail;
 168                 strv_free(r);
 169                 r = t;
 170         }
 171
 172         if (!(t = strv_merge_concat(r, config_dirs, "/systemd/session")))
 173                 goto finish;
 174         strv_free(r);
 175         r = t;
 176
 177         if (!(t = strv_append(r, SESSION_CONFIG_UNIT_PATH)))
 178                 goto fail;
 179         strv_free(r);
 180         r = t;
 181
 182         if (data_home) {
 183                 if (!(t = strv_append(r, data_home)))
 184                         goto fail;
 185                 strv_free(r);
 186                 r = t;
 187         }
 188
 189         if (!(t = strv_merge_concat(r, data_dirs, "/systemd/session")))
 190                 goto fail;
 191         strv_free(r);
 192         r = t;
 193
 194         if (!(t = strv_append(r, SESSION_DATA_UNIT_PATH)))
 195                 goto fail;
 196         strv_free(r);
 197         r = t;
 198
 199         if (!strv_path_make_absolute_cwd(r))
 200             goto fail;
 201
 202 finish:
 203         free(config_home);
 204         strv_free(config_dirs);
 205         free(data_home);
 206         strv_free(data_dirs);
 207
 208         return r;
 209
 210 fail:
 211         strv_free(r);
 212         r = NULL;
 213         goto finish;
 214 }
 215
 216 static int manager_find_paths(Manager *m) {
 217         const char *e;
 218         char *t;
 219
 220         assert(m);
 221
 222         /* First priority is whatever has been passed to us via env
 223          * vars */
 224         if ((e = getenv("SYSTEMD_UNIT_PATH")))
 225                 if (!(m->unit_path = split_path_and_make_absolute(e)))
 226                         return -ENOMEM;
 227
 228         if (strv_isempty(m->unit_path)) {
 229
 230                 /* Nothing is set, so let's figure something out. */
 231                 strv_free(m->unit_path);
 232
 233                 if (m->running_as == MANAGER_SESSION) {
 234                         if (!(m->unit_path = session_dirs()))
 235                                 return -ENOMEM;
 236                 } else
 237                         if (!(m->unit_path = strv_new(
 238                                               SYSTEM_CONFIG_UNIT_PATH,  /* /etc/systemd/system/ */
 239                                               SYSTEM_DATA_UNIT_PATH,    /* /lib/systemd/system/ */
 240                                               NULL)))
 241                                 return -ENOMEM;
 242         }
 243
 244         if (m->running_as == MANAGER_INIT) {
 245                 /* /etc/init.d/ compativility does not matter to users */
 246
 247                 if ((e = getenv("SYSTEMD_SYSVINIT_PATH")))
 248                         if (!(m->sysvinit_path = split_path_and_make_absolute(e)))
 249                                 return -ENOMEM;
 250
 251                 if (strv_isempty(m->sysvinit_path)) {
 252                         strv_free(m->sysvinit_path);
 253
 254                         if (!(m->sysvinit_path = strv_new(
 255                                               SYSTEM_SYSVINIT_PATH,     /* /etc/init.d/ */
 256                                               NULL)))
 257                                 return -ENOMEM;
 258                 }
 259
 260                 if ((e = getenv("SYSTEMD_SYSVRCND_PATH")))
 261                         if (!(m->sysvrcnd_path = split_path_and_make_absolute(e)))
 262                                 return -ENOMEM;
 263
 264                 if (strv_isempty(m->sysvrcnd_path)) {
 265                         strv_free(m->sysvrcnd_path);
 266
 267                         if (!(m->sysvrcnd_path = strv_new(
 268                                               SYSTEM_SYSVRCND_PATH,     /* /etc/rcN.d/ */
 269                                               NULL)))
 270                                 return -ENOMEM;
 271                 }
 272         }
 273
 274         strv_uniq(m->unit_path);
 275         strv_uniq(m->sysvinit_path);
 276         strv_uniq(m->sysvrcnd_path);
 277
 278         assert(!strv_isempty(m->unit_path));
 279         if (!(t = strv_join(m->unit_path, "\n\t")))
 280                 return -ENOMEM;
 281         log_debug("Looking for unit files in:\n\t%s", t);
 282         free(t);
 283
 284         if (!strv_isempty(m->sysvinit_path)) {
 285
 286                 if (!(t = strv_join(m->sysvinit_path, "\n\t")))
 287                         return -ENOMEM;
 288
 289                 log_debug("Looking for SysV init scripts in:\n\t%s", t);
 290                 free(t);
 291         } else
 292                 log_debug("Ignoring SysV init scripts.");
 293
 294         if (!strv_isempty(m->sysvrcnd_path)) {
 295
 296                 if (!(t = strv_join(m->sysvrcnd_path, "\n\t")))
 297                         return -ENOMEM;
 298
 299                 log_debug("Looking for SysV rcN.d links in:\n\t%s", t);
 300                 free(t);
 301         } else
 302                 log_debug("Ignoring SysV rcN.d links.");
 303
 304         return 0;
 305 }
 306
 307 int manager_new(ManagerRunningAs running_as, bool confirm_spawn, Manager **_m) {
 308         Manager *m;
 309         int r = -ENOMEM;
 310
 311         assert(_m);
 312         assert(running_as >= 0);
 313         assert(running_as < _MANAGER_RUNNING_AS_MAX);
 314
 315         if (!(m = new0(Manager, 1)))
 316                 return -ENOMEM;
 317
 318         m->boot_timestamp = now(CLOCK_REALTIME);
 319
 320         m->running_as = running_as;
 321         m->confirm_spawn = confirm_spawn;
 322
 323         m->signal_watch.fd = m->mount_watch.fd = m->udev_watch.fd = m->epoll_fd = -1;
 324         m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
 325
 326         if (!(m->units = hashmap_new(string_hash_func, string_compare_func)))
 327                 goto fail;
 328
 329         if (!(m->jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
 330                 goto fail;
 331
 332         if (!(m->transaction_jobs = hashmap_new(trivial_hash_func, trivial_compare_func)))
 333                 goto fail;
 334
 335         if (!(m->watch_pids = hashmap_new(trivial_hash_func, trivial_compare_func)))
 336                 goto fail;
 337
 338         if (!(m->cgroup_bondings = hashmap_new(string_hash_func, string_compare_func)))
 339                 goto fail;
 340
 341         if ((m->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
 342                 goto fail;
 343
 344         if ((r = manager_find_paths(m)) < 0)
 345                 goto fail;
 346
 347         if ((r = manager_setup_signals(m)) < 0)
 348                 goto fail;
 349
 350         if ((r = manager_setup_cgroup(m)) < 0)
 351                 goto fail;
 352
 353         /* Try to connect to the busses, if possible. */
 354         if ((r = bus_init_system(m)) < 0 ||
 355             (r = bus_init_api(m)) < 0)
 356                 goto fail;
 357
 358         *_m = m;
 359         return 0;
 360
 361 fail:
 362         manager_free(m);
 363         return r;
 364 }
 365
 366 static unsigned manager_dispatch_cleanup_queue(Manager *m) {
 367         Meta *meta;
 368         unsigned n = 0;
 369
 370         assert(m);
 371
 372         while ((meta = m->cleanup_queue)) {
 373                 assert(meta->in_cleanup_queue);
 374
 375                 unit_free(UNIT(meta));
 376                 n++;
 377         }
 378
 379         return n;
 380 }
 381
 382 void manager_free(Manager *m) {
 383         UnitType c;
 384         Unit *u;
 385         Job *j;
 386
 387         assert(m);
 388
 389         while ((j = hashmap_first(m->transaction_jobs)))
 390                 job_free(j);
 391
 392         while ((u = hashmap_first(m->units)))
 393                 unit_free(u);
 394
 395         manager_dispatch_cleanup_queue(m);
 396
 397         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 398                 if (unit_vtable[c]->shutdown)
 399                         unit_vtable[c]->shutdown(m);
 400
 401         manager_shutdown_cgroup(m);
 402
 403         bus_done_api(m);
 404         bus_done_system(m);
 405
 406         hashmap_free(m->units);
 407         hashmap_free(m->jobs);
 408         hashmap_free(m->transaction_jobs);
 409         hashmap_free(m->watch_pids);
 410
 411         if (m->epoll_fd >= 0)
 412                 close_nointr(m->epoll_fd);
 413         if (m->signal_watch.fd >= 0)
 414                 close_nointr(m->signal_watch.fd);
 415
 416         strv_free(m->unit_path);
 417         strv_free(m->sysvinit_path);
 418         strv_free(m->sysvrcnd_path);
 419
 420         free(m->cgroup_controller);
 421         free(m->cgroup_hierarchy);
 422
 423         assert(hashmap_isempty(m->cgroup_bondings));
 424         hashmap_free(m->cgroup_bondings);
 425
 426         free(m);
 427 }
 428
 429 int manager_coldplug(Manager *m) {
 430         int r;
 431         UnitType c;
 432         Iterator i;
 433         Unit *u;
 434         char *k;
 435
 436         assert(m);
 437
 438         /* First, let's ask every type to load all units from
 439          * disk/kernel that it might know */
 440         for (c = 0; c < _UNIT_TYPE_MAX; c++)
 441                 if (unit_vtable[c]->enumerate)
 442                         if ((r = unit_vtable[c]->enumerate(m)) < 0)
 443                                 return r;
 444
 445         manager_dispatch_load_queue(m);
 446
 447         /* Then, let's set up their initial state. */
 448         HASHMAP_FOREACH_KEY(u, k, m->units, i) {
 449
 450                 /* ignore aliases */
 451                 if (unit_id(u) != k)
 452                         continue;
 453
 454                 if (UNIT_VTABLE(u)->coldplug)
 455                         if ((r = UNIT_VTABLE(u)->coldplug(u)) < 0)
 456                                 return r;
 457         }
 458
 459         /* Now that the initial devices are available, let's see if we
 460          * can write the utmp file */
 461         manager_write_utmp_reboot(m);
 462
 463         return 0;
 464 }
 465
 466 static void transaction_delete_job(Manager *m, Job *j, bool delete_dependencies) {
 467         assert(m);
 468         assert(j);
 469
 470         /* Deletes one job from the transaction */
 471
 472         manager_transaction_unlink_job(m, j, delete_dependencies);
 473
 474         if (!j->installed)
 475                 job_free(j);
 476 }
 477
 478 static void transaction_delete_unit(Manager *m, Unit *u) {
 479         Job *j;
 480
 481         /* Deletes all jobs associated with a certain unit from the
 482          * transaction */
 483
 484         while ((j = hashmap_get(m->transaction_jobs, u)))
 485                 transaction_delete_job(m, j, true);
 486 }
 487
 488 static void transaction_clean_dependencies(Manager *m) {
 489         Iterator i;
 490         Job *j;
 491
 492         assert(m);
 493
 494         /* Drops all dependencies of all installed jobs */
 495
 496         HASHMAP_FOREACH(j, m->jobs, i) {
 497                 while (j->subject_list)
 498                         job_dependency_free(j->subject_list);
 499                 while (j->object_list)
 500                         job_dependency_free(j->object_list);
 501         }
 502
 503         assert(!m->transaction_anchor);
 504 }
 505
 506 static void transaction_abort(Manager *m) {
 507         Job *j;
 508
 509         assert(m);
 510
 511         while ((j = hashmap_first(m->transaction_jobs)))
 512                 if (j->installed)
 513                         transaction_delete_job(m, j, true);
 514                 else
 515                         job_free(j);
 516
 517         assert(hashmap_isempty(m->transaction_jobs));
 518
 519         transaction_clean_dependencies(m);
 520 }
 521
 522 static void transaction_find_jobs_that_matter_to_anchor(Manager *m, Job *j, unsigned generation) {
 523         JobDependency *l;
 524
 525         assert(m);
 526
 527         /* A recursive sweep through the graph that marks all units
 528          * that matter to the anchor job, i.e. are directly or
 529          * indirectly a dependency of the anchor job via paths that
 530          * are fully marked as mattering. */
 531
 532         if (j)
 533                 l = j->subject_list;
 534         else
 535                 l = m->transaction_anchor;
 536
 537         LIST_FOREACH(subject, l, l) {
 538
 539                 /* This link does not matter */
 540                 if (!l->matters)
 541                         continue;
 542
 543                 /* This unit has already been marked */
 544                 if (l->object->generation == generation)
 545                         continue;
 546
 547                 l->object->matters_to_anchor = true;
 548                 l->object->generation = generation;
 549
 550                 transaction_find_jobs_that_matter_to_anchor(m, l->object, generation);
 551         }
 552 }
 553
 554 static void transaction_merge_and_delete_job(Manager *m, Job *j, Job *other, JobType t) {
 555         JobDependency *l, *last;
 556
 557         assert(j);
 558         assert(other);
 559         assert(j->unit == other->unit);
 560         assert(!j->installed);
 561
 562         /* Merges 'other' into 'j' and then deletes j. */
 563
 564         j->type = t;
 565         j->state = JOB_WAITING;
 566         j->forced = j->forced || other->forced;
 567
 568         j->matters_to_anchor = j->matters_to_anchor || other->matters_to_anchor;
 569
 570         /* Patch us in as new owner of the JobDependency objects */
 571         last = NULL;
 572         LIST_FOREACH(subject, l, other->subject_list) {
 573                 assert(l->subject == other);
 574                 l->subject = j;
 575                 last = l;
 576         }
 577
 578         /* Merge both lists */
 579         if (last) {
 580                 last->subject_next = j->subject_list;
 581                 if (j->subject_list)
 582                         j->subject_list->subject_prev = last;
 583                 j->subject_list = other->subject_list;
 584         }
 585
 586         /* Patch us in as new owner of the JobDependency objects */
 587         last = NULL;
 588         LIST_FOREACH(object, l, other->object_list) {
 589                 assert(l->object == other);
 590                 l->object = j;
 591                 last = l;
 592         }
 593
 594         /* Merge both lists */
 595         if (last) {
 596                 last->object_next = j->object_list;
 597                 if (j->object_list)
 598                         j->object_list->object_prev = last;
 599                 j->object_list = other->object_list;
 600         }
 601
 602         /* Kill the other job */
 603         other->subject_list = NULL;
 604         other->object_list = NULL;
 605         transaction_delete_job(m, other, true);
 606 }
 607
 608 static int delete_one_unmergeable_job(Manager *m, Job *j) {
 609         Job *k;
 610
 611         assert(j);
 612
 613         /* Tries to delete one item in the linked list
 614          * j->transaction_next->transaction_next->... that conflicts
 615          * whith another one, in an attempt to make an inconsistent
 616          * transaction work. */
 617
 618         /* We rely here on the fact that if a merged with b does not
 619          * merge with c, either a or b merge with c neither */
 620         LIST_FOREACH(transaction, j, j)
 621                 LIST_FOREACH(transaction, k, j->transaction_next) {
 622                         Job *d;
 623
 624                         /* Is this one mergeable? Then skip it */
 625                         if (job_type_is_mergeable(j->type, k->type))
 626                                 continue;
 627
 628                         /* Ok, we found two that conflict, let's see if we can
 629                          * drop one of them */
 630                         if (!j->matters_to_anchor)
 631                                 d = j;
 632                         else if (!k->matters_to_anchor)
 633                                 d = k;
 634                         else
 635                                 return -ENOEXEC;
 636
 637                         /* Ok, we can drop one, so let's do so. */
 638                         log_debug("Trying to fix job merging by deleting job %s/%s", unit_id(d->unit), job_type_to_string(d->type));
 639                         transaction_delete_job(m, d, true);
 640                         return 0;
 641                 }
 642
 643         return -EINVAL;
 644 }
 645
 646 static int transaction_merge_jobs(Manager *m) {
 647         Job *j;
 648         Iterator i;
 649         int r;
 650
 651         assert(m);
 652
 653         /* First step, check whether any of the jobs for one specific
 654          * task conflict. If so, try to drop one of them. */
 655         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 656                 JobType t;
 657                 Job *k;
 658
 659                 t = j->type;
 660                 LIST_FOREACH(transaction, k, j->transaction_next) {
 661                         if ((r = job_type_merge(&t, k->type)) >= 0)
 662                                 continue;
 663
 664                         /* OK, we could not merge all jobs for this
 665                          * action. Let's see if we can get rid of one
 666                          * of them */
 667
 668                         if ((r = delete_one_unmergeable_job(m, j)) >= 0)
 669                                 /* Ok, we managed to drop one, now
 670                                  * let's ask our callers to call us
 671                                  * again after garbage collecting */
 672                                 return -EAGAIN;
 673
 674                         /* We couldn't merge anything. Failure */
 675                         return r;
 676                 }
 677         }
 678
 679         /* Second step, merge the jobs. */
 680         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 681                 JobType t = j->type;
 682                 Job *k;
 683
 684                 /* Merge all transactions */
 685                 LIST_FOREACH(transaction, k, j->transaction_next)
 686                         assert_se(job_type_merge(&t, k->type) == 0);
 687
 688                 /* If an active job is mergeable, merge it too */
 689                 if (j->unit->meta.job)
 690                         job_type_merge(&t, j->unit->meta.job->type); /* Might fail. Which is OK */
 691
 692                 while ((k = j->transaction_next)) {
 693                         if (j->installed) {
 694                                 transaction_merge_and_delete_job(m, k, j, t);
 695                                 j = k;
 696                         } else
 697                                 transaction_merge_and_delete_job(m, j, k, t);
 698                 }
 699
 700                 assert(!j->transaction_next);
 701                 assert(!j->transaction_prev);
 702         }
 703
 704         return 0;
 705 }
 706
 707 static void transaction_drop_redundant(Manager *m) {
 708         bool again;
 709
 710         assert(m);
 711
 712         /* Goes through the transaction and removes all jobs that are
 713          * a noop */
 714
 715         do {
 716                 Job *j;
 717                 Iterator i;
 718
 719                 again = false;
 720
 721                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 722                         bool changes_something = false;
 723                         Job *k;
 724
 725                         LIST_FOREACH(transaction, k, j) {
 726
 727                                 if (!job_is_anchor(k) &&
 728                                     job_type_is_redundant(k->type, unit_active_state(k->unit)))
 729                                         continue;
 730
 731                                 changes_something = true;
 732                                 break;
 733                         }
 734
 735                         if (changes_something)
 736                                 continue;
 737
 738                         log_debug("Found redundant job %s/%s, dropping.", unit_id(j->unit), job_type_to_string(j->type));
 739                         transaction_delete_job(m, j, false);
 740                         again = true;
 741                         break;
 742                 }
 743
 744         } while (again);
 745 }
 746
 747 static bool unit_matters_to_anchor(Unit *u, Job *j) {
 748         assert(u);
 749         assert(!j->transaction_prev);
 750
 751         /* Checks whether at least one of the jobs for this unit
 752          * matters to the anchor. */
 753
 754         LIST_FOREACH(transaction, j, j)
 755                 if (j->matters_to_anchor)
 756                         return true;
 757
 758         return false;
 759 }
 760
 761 static int transaction_verify_order_one(Manager *m, Job *j, Job *from, unsigned generation) {
 762         Iterator i;
 763         Unit *u;
 764         int r;
 765
 766         assert(m);
 767         assert(j);
 768         assert(!j->transaction_prev);
 769
 770         /* Does a recursive sweep through the ordering graph, looking
 771          * for a cycle. If we find cycle we try to break it. */
 772
 773         /* Did we find a cycle? */
 774         if (j->marker && j->generation == generation) {
 775                 Job *k;
 776
 777                 /* So, we already have been here. We have a
 778                  * cycle. Let's try to break it. We go backwards in
 779                  * our path and try to find a suitable job to
 780                  * remove. We use the marker to find our way back,
 781                  * since smart how we are we stored our way back in
 782                  * there. */
 783
 784                 log_debug("Found ordering cycle on %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 785
 786                 for (k = from; k; k = (k->generation == generation ? k->marker : NULL)) {
 787
 788                         log_debug("Walked on cycle path to %s/%s", unit_id(k->unit), job_type_to_string(k->type));
 789
 790                         if (!k->installed &&
 791                             !unit_matters_to_anchor(k->unit, k)) {
 792                                 /* Ok, we can drop this one, so let's
 793                                  * do so. */
 794                                 log_debug("Breaking order cycle by deleting job %s/%s", unit_id(k->unit), job_type_to_string(k->type));
 795                                 transaction_delete_unit(m, k->unit);
 796                                 return -EAGAIN;
 797                         }
 798
 799                         /* Check if this in fact was the beginning of
 800                          * the cycle */
 801                         if (k == j)
 802                                 break;
 803                 }
 804
 805                 log_debug("Unable to break cycle");
 806
 807                 return -ENOEXEC;
 808         }
 809
 810         /* Make the marker point to where we come from, so that we can
 811          * find our way backwards if we want to break a cycle */
 812         j->marker = from;
 813         j->generation = generation;
 814
 815         /* We assume that the the dependencies are bidirectional, and
 816          * hence can ignore UNIT_AFTER */
 817         SET_FOREACH(u, j->unit->meta.dependencies[UNIT_BEFORE], i) {
 818                 Job *o;
 819
 820                 /* Is there a job for this unit? */
 821                 if (!(o = hashmap_get(m->transaction_jobs, u)))
 822
 823                         /* Ok, there is no job for this in the
 824                          * transaction, but maybe there is already one
 825                          * running? */
 826                         if (!(o = u->meta.job))
 827                                 continue;
 828
 829                 if ((r = transaction_verify_order_one(m, o, j, generation)) < 0)
 830                         return r;
 831         }
 832
 833         /* Ok, let's backtrack, and remember that this entry is not on
 834          * our path anymore. */
 835         j->marker = NULL;
 836
 837         return 0;
 838 }
 839
 840 static int transaction_verify_order(Manager *m, unsigned *generation) {
 841         Job *j;
 842         int r;
 843         Iterator i;
 844
 845         assert(m);
 846         assert(generation);
 847
 848         /* Check if the ordering graph is cyclic. If it is, try to fix
 849          * that up by dropping one of the jobs. */
 850
 851         HASHMAP_FOREACH(j, m->transaction_jobs, i)
 852                 if ((r = transaction_verify_order_one(m, j, NULL, (*generation)++)) < 0)
 853                         return r;
 854
 855         return 0;
 856 }
 857
 858 static void transaction_collect_garbage(Manager *m) {
 859         bool again;
 860
 861         assert(m);
 862
 863         /* Drop jobs that are not required by any other job */
 864
 865         do {
 866                 Iterator i;
 867                 Job *j;
 868
 869                 again = false;
 870
 871                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 872                         if (j->object_list)
 873                                 continue;
 874
 875                         log_debug("Garbage collecting job %s/%s", unit_id(j->unit), job_type_to_string(j->type));
 876                         transaction_delete_job(m, j, true);
 877                         again = true;
 878                         break;
 879                 }
 880
 881         } while (again);
 882 }
 883
 884 static int transaction_is_destructive(Manager *m, JobMode mode) {
 885         Iterator i;
 886         Job *j;
 887
 888         assert(m);
 889
 890         /* Checks whether applying this transaction means that
 891          * existing jobs would be replaced */
 892
 893         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 894
 895                 /* Assume merged */
 896                 assert(!j->transaction_prev);
 897                 assert(!j->transaction_next);
 898
 899                 if (j->unit->meta.job &&
 900                     j->unit->meta.job != j &&
 901                     !job_type_is_superset(j->type, j->unit->meta.job->type))
 902                         return -EEXIST;
 903         }
 904
 905         return 0;
 906 }
 907
 908 static void transaction_minimize_impact(Manager *m) {
 909         bool again;
 910         assert(m);
 911
 912         /* Drops all unnecessary jobs that reverse already active jobs
 913          * or that stop a running service. */
 914
 915         do {
 916                 Job *j;
 917                 Iterator i;
 918
 919                 again = false;
 920
 921                 HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 922                         LIST_FOREACH(transaction, j, j) {
 923                                 bool stops_running_service, changes_existing_job;
 924
 925                                 /* If it matters, we shouldn't drop it */
 926                                 if (j->matters_to_anchor)
 927                                         continue;
 928
 929                                 /* Would this stop a running service?
 930                                  * Would this change an existing job?
 931                                  * If so, let's drop this entry */
 932
 933                                 stops_running_service =
 934                                         j->type == JOB_STOP && UNIT_IS_ACTIVE_OR_ACTIVATING(unit_active_state(j->unit));
 935
 936                                 changes_existing_job =
 937                                         j->unit->meta.job && job_type_is_conflicting(j->type, j->unit->meta.job->state);
 938
 939                                 if (!stops_running_service && !changes_existing_job)
 940                                         continue;
 941
 942                                 if (stops_running_service)
 943                                         log_debug("%s/%s would stop a running service.", unit_id(j->unit), job_type_to_string(j->type));
 944
 945                                 if (changes_existing_job)
 946                                         log_debug("%s/%s would change existing job.", unit_id(j->unit), job_type_to_string(j->type));
 947
 948                                 /* Ok, let's get rid of this */
 949                                 log_debug("Deleting %s/%s to minimize impact.", unit_id(j->unit), job_type_to_string(j->type));
 950
 951                                 transaction_delete_job(m, j, true);
 952                                 again = true;
 953                                 break;
 954                         }
 955
 956                         if (again)
 957                                 break;
 958                 }
 959
 960         } while (again);
 961 }
 962
 963 static int transaction_apply(Manager *m, JobMode mode) {
 964         Iterator i;
 965         Job *j;
 966         int r;
 967
 968         /* Moves the transaction jobs to the set of active jobs */
 969
 970         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
 971                 /* Assume merged */
 972                 assert(!j->transaction_prev);
 973                 assert(!j->transaction_next);
 974
 975                 if (j->installed)
 976                         continue;
 977
 978                 if ((r = hashmap_put(m->jobs, UINT32_TO_PTR(j->id), j)) < 0)
 979                         goto rollback;
 980         }
 981
 982         while ((j = hashmap_steal_first(m->transaction_jobs))) {
 983                 if (j->installed)
 984                         continue;
 985
 986                 if (j->unit->meta.job)
 987                         job_free(j->unit->meta.job);
 988
 989                 j->unit->meta.job = j;
 990                 j->installed = true;
 991
 992                 /* We're fully installed. Now let's free data we don't
 993                  * need anymore. */
 994
 995                 assert(!j->transaction_next);
 996                 assert(!j->transaction_prev);
 997
 998                 job_add_to_run_queue(j);
 999                 job_add_to_dbus_queue(j);
1000         }
1001
1002         /* As last step, kill all remaining job dependencies. */
1003         transaction_clean_dependencies(m);
1004
1005         return 0;
1006
1007 rollback:
1008
1009         HASHMAP_FOREACH(j, m->transaction_jobs, i) {
1010                 if (j->installed)
1011                         continue;
1012
1013                 hashmap_remove(m->jobs, UINT32_TO_PTR(j->id));
1014         }
1015
1016         return r;
1017 }
1018
1019 static int transaction_activate(Manager *m, JobMode mode) {
1020         int r;
1021         unsigned generation = 1;
1022
1023         assert(m);
1024
1025         /* This applies the changes recorded in transaction_jobs to
1026          * the actual list of jobs, if possible. */
1027
1028         /* First step: figure out which jobs matter */
1029         transaction_find_jobs_that_matter_to_anchor(m, NULL, generation++);
1030
1031         /* Second step: Try not to stop any running services if
1032          * we don't have to. Don't try to reverse running
1033          * jobs if we don't have to. */
1034         transaction_minimize_impact(m);
1035
1036         /* Third step: Drop redundant jobs */
1037         transaction_drop_redundant(m);
1038
1039         for (;;) {
1040                 /* Fourth step: Let's remove unneeded jobs that might
1041                  * be lurking. */
1042                 transaction_collect_garbage(m);
1043
1044                 /* Fifth step: verify order makes sense and correct
1045                  * cycles if necessary and possible */
1046                 if ((r = transaction_verify_order(m, &generation)) >= 0)
1047                         break;
1048
1049                 if (r != -EAGAIN) {
1050                         log_debug("Requested transaction contains an unfixable cyclic ordering dependency: %s", strerror(-r));
1051                         goto rollback;
1052                 }
1053
1054                 /* Let's see if the resulting transaction ordering
1055                  * graph is still cyclic... */
1056         }
1057
1058         for (;;) {
1059                 /* Sixth step: let's drop unmergeable entries if
1060                  * necessary and possible, merge entries we can
1061                  * merge */
1062                 if ((r = transaction_merge_jobs(m)) >= 0)
1063                         break;
1064
1065                 if (r != -EAGAIN) {
1066                         log_debug("Requested transaction contains unmergable jobs: %s", strerror(-r));
1067                         goto rollback;
1068                 }
1069
1070                 /* Seventh step: an entry got dropped, let's garbage
1071                  * collect its dependencies. */
1072                 transaction_collect_garbage(m);
1073
1074                 /* Let's see if the resulting transaction still has
1075                  * unmergeable entries ... */
1076         }
1077
1078         /* Eights step: Drop redundant jobs again, if the merging now allows us to drop more. */
1079         transaction_drop_redundant(m);
1080
1081         /* Ninth step: check whether we can actually apply this */
1082         if (mode == JOB_FAIL)
1083                 if ((r = transaction_is_destructive(m, mode)) < 0) {
1084                         log_debug("Requested transaction contradicts existing jobs: %s", strerror(-r));
1085                         goto rollback;
1086                 }
1087
1088         /* Tenth step: apply changes */
1089         if ((r = transaction_apply(m, mode)) < 0) {
1090                 log_debug("Failed to apply transaction: %s", strerror(-r));
1091                 goto rollback;
1092         }
1093
1094         assert(hashmap_isempty(m->transaction_jobs));
1095         assert(!m->transaction_anchor);
1096
1097         return 0;
1098
1099 rollback:
1100         transaction_abort(m);
1101         return r;
1102 }
1103
1104 static Job* transaction_add_one_job(Manager *m, JobType type, Unit *unit, bool force, bool *is_new) {
1105         Job *j, *f;
1106         int r;
1107
1108         assert(m);
1109         assert(unit);
1110
1111         /* Looks for an axisting prospective job and returns that. If
1112          * it doesn't exist it is created and added to the prospective
1113          * jobs list. */
1114
1115         f = hashmap_get(m->transaction_jobs, unit);
1116
1117         LIST_FOREACH(transaction, j, f) {
1118                 assert(j->unit == unit);
1119
1120                 if (j->type == type) {
1121                         if (is_new)
1122                                 *is_new = false;
1123                         return j;
1124                 }
1125         }
1126
1127         if (unit->meta.job && unit->meta.job->type == type)
1128                 j = unit->meta.job;
1129         else if (!(j = job_new(m, type, unit)))
1130                 return NULL;
1131
1132         j->generation = 0;
1133         j->marker = NULL;
1134         j->matters_to_anchor = false;
1135         j->forced = force;
1136
1137         LIST_PREPEND(Job, transaction, f, j);
1138
1139         if ((r = hashmap_replace(m->transaction_jobs, unit, f)) < 0) {
1140                 job_free(j);
1141                 return NULL;
1142         }
1143
1144         if (is_new)
1145                 *is_new = true;
1146
1147         log_debug("Added job %s/%s to transaction.", unit_id(unit), job_type_to_string(type));
1148
1149         return j;
1150 }
1151
1152 void manager_transaction_unlink_job(Manager *m, Job *j, bool delete_dependencies) {
1153         assert(m);
1154         assert(j);
1155
1156         if (j->transaction_prev)
1157                 j->transaction_prev->transaction_next = j->transaction_next;
1158         else if (j->transaction_next)
1159                 hashmap_replace(m->transaction_jobs, j->unit, j->transaction_next);
1160         else
1161                 hashmap_remove_value(m->transaction_jobs, j->unit, j);
1162
1163         if (j->transaction_next)
1164                 j->transaction_next->transaction_prev = j->transaction_prev;
1165
1166         j->transaction_prev = j->transaction_next = NULL;
1167
1168         while (j->subject_list)
1169                 job_dependency_free(j->subject_list);
1170
1171         while (j->object_list) {
1172                 Job *other = j->object_list->matters ? j->object_list->subject : NULL;
1173
1174                 job_dependency_free(j->object_list);
1175
1176                 if (other && delete_dependencies) {
1177                         log_debug("Deleting job %s/%s as dependency of job %s/%s",
1178                                   unit_id(other->unit), job_type_to_string(other->type),
1179                                   unit_id(j->unit), job_type_to_string(j->type));
1180                         transaction_delete_job(m, other, delete_dependencies);
1181                 }
1182         }
1183 }
1184
1185 static int transaction_add_job_and_dependencies(Manager *m, JobType type, Unit *unit, Job *by, bool matters, bool force, Job **_ret) {
1186         Job *ret;
1187         Iterator i;
1188         Unit *dep;
1189         int r;
1190         bool is_new;
1191
1192         assert(m);
1193         assert(type < _JOB_TYPE_MAX);
1194         assert(unit);
1195
1196         if (unit->meta.load_state != UNIT_LOADED)
1197                 return -EINVAL;
1198
1199         if (!unit_job_is_applicable(unit, type))
1200                 return -EBADR;
1201
1202         /* First add the job. */
1203         if (!(ret = transaction_add_one_job(m, type, unit, force, &is_new)))
1204                 return -ENOMEM;
1205
1206         /* Then, add a link to the job. */
1207         if (!job_dependency_new(by, ret, matters))
1208                 return -ENOMEM;
1209
1210         if (is_new) {
1211                 /* Finally, recursively add in all dependencies. */
1212                 if (type == JOB_START || type == JOB_RELOAD_OR_START) {
1213                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRES], i)
1214                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
1215                                         goto fail;
1216                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUIRES], i)
1217                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
1218                                         goto fail;
1219                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_WANTS], i)
1220                                 if ((r = transaction_add_job_and_dependencies(m, JOB_START, dep, ret, false, force, NULL)) < 0)
1221                                         log_warning("Cannot add dependency job for unit %s, ignoring: %s", unit_id(dep), strerror(-r));
1222                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUISITE], i)
1223                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
1224                                         goto fail;
1225                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_SOFT_REQUISITE], i)
1226                                 if ((r = transaction_add_job_and_dependencies(m, JOB_VERIFY_ACTIVE, dep, ret, !force, force, NULL)) < 0 && r != -EBADR)
1227                                         goto fail;
1228                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_CONFLICTS], i)
1229                                 if ((r = transaction_add_job_and_dependencies(m, JOB_STOP, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
1230                                         goto fail;
1231
1232                 } else if (type == JOB_STOP || type == JOB_RESTART || type == JOB_TRY_RESTART) {
1233
1234                         SET_FOREACH(dep, ret->unit->meta.dependencies[UNIT_REQUIRED_BY], i)
1235                                 if ((r = transaction_add_job_and_dependencies(m, type, dep, ret, true, force, NULL)) < 0 && r != -EBADR)
1236                                         goto fail;
1237                 }
1238
1239                 /* JOB_VERIFY_STARTED, JOB_RELOAD require no dependency handling */
1240         }
1241
1242         if (_ret)
1243                 *_ret = ret;
1244
1245         return 0;
1246
1247 fail:
1248         return r;
1249 }
1250
1251 int manager_add_job(Manager *m, JobType type, Unit *unit, JobMode mode, bool force, Job **_ret) {
1252         int r;
1253         Job *ret;
1254
1255         assert(m);
1256         assert(type < _JOB_TYPE_MAX);
1257         assert(unit);
1258         assert(mode < _JOB_MODE_MAX);
1259
1260         log_debug("Trying to enqueue job %s/%s", unit_id(unit), job_type_to_string(type));
1261
1262         if ((r = transaction_add_job_and_dependencies(m, type, unit, NULL, true, force, &ret)) < 0) {
1263                 transaction_abort(m);
1264                 return r;
1265         }
1266
1267         if ((r = transaction_activate(m, mode)) < 0)
1268                 return r;
1269
1270         log_debug("Enqueued job %s/%s as %u", unit_id(unit), job_type_to_string(type), (unsigned) ret->id);
1271
1272         if (_ret)
1273                 *_ret = ret;
1274
1275         return 0;
1276 }
1277
1278 int manager_add_job_by_name(Manager *m, JobType type, const char *name, JobMode mode, bool force, Job **_ret) {
1279         Unit *unit;
1280         int r;
1281
1282         assert(m);
1283         assert(type < _JOB_TYPE_MAX);
1284         assert(name);
1285         assert(mode < _JOB_MODE_MAX);
1286
1287         if ((r = manager_load_unit(m, name, &unit)) < 0)
1288                 return r;
1289
1290         return manager_add_job(m, type, unit, mode, force, _ret);
1291 }
1292
1293 Job *manager_get_job(Manager *m, uint32_t id) {
1294         assert(m);
1295
1296         return hashmap_get(m->jobs, UINT32_TO_PTR(id));
1297 }
1298
1299 Unit *manager_get_unit(Manager *m, const char *name) {
1300         assert(m);
1301         assert(name);
1302
1303         return hashmap_get(m->units, name);
1304 }
1305
1306 unsigned manager_dispatch_load_queue(Manager *m) {
1307         Meta *meta;
1308         unsigned n = 0;
1309
1310         assert(m);
1311
1312         /* Make sure we are not run recursively */
1313         if (m->dispatching_load_queue)
1314                 return 0;
1315
1316         m->dispatching_load_queue = true;
1317
1318         /* Dispatches the load queue. Takes a unit from the queue and
1319          * tries to load its data until the queue is empty */
1320
1321         while ((meta = m->load_queue)) {
1322                 assert(meta->in_load_queue);
1323
1324                 unit_load(UNIT(meta));
1325                 n++;
1326         }
1327
1328         m->dispatching_load_queue = false;
1329         return n;
1330 }
1331
1332 int manager_load_unit(Manager *m, const char *path, Unit **_ret) {
1333         Unit *ret;
1334         int r;
1335         const char *name;
1336
1337         assert(m);
1338         assert(path);
1339         assert(_ret);
1340
1341         /* This will load the service information files, but not actually
1342          * start any services or anything. */
1343
1344         name = file_name_from_path(path);
1345
1346         if ((ret = manager_get_unit(m, name))) {
1347                 *_ret = ret;
1348                 return 0;
1349         }
1350
1351         if (!(ret = unit_new(m)))
1352                 return -ENOMEM;
1353
1354         if (is_path(path)) {
1355                 if (!(ret->meta.fragment_path = strdup(path))) {
1356                         unit_free(ret);
1357                         return -ENOMEM;
1358                 }
1359         }
1360
1361         if ((r = unit_add_name(ret, name)) < 0) {
1362                 unit_free(ret);
1363                 return r;
1364         }
1365
1366         unit_add_to_load_queue(ret);
1367         unit_add_to_dbus_queue(ret);
1368
1369         manager_dispatch_load_queue(m);
1370
1371         *_ret = unit_follow_merge(ret);
1372         return 0;
1373 }
1374
1375 void manager_dump_jobs(Manager *s, FILE *f, const char *prefix) {
1376         Iterator i;
1377         Job *j;
1378
1379         assert(s);
1380         assert(f);
1381
1382         HASHMAP_FOREACH(j, s->jobs, i)
1383                 job_dump(j, f, prefix);
1384 }
1385
1386 void manager_dump_units(Manager *s, FILE *f, const char *prefix) {
1387         Iterator i;
1388         Unit *u;
1389         const char *t;
1390
1391         assert(s);
1392         assert(f);
1393
1394         HASHMAP_FOREACH_KEY(u, t, s->units, i)
1395                 if (unit_id(u) == t)
1396                         unit_dump(u, f, prefix);
1397 }
1398
1399 void manager_clear_jobs(Manager *m) {
1400         Job *j;
1401
1402         assert(m);
1403
1404         transaction_abort(m);
1405
1406         while ((j = hashmap_first(m->jobs)))
1407                 job_free(j);
1408 }
1409
1410 unsigned manager_dispatch_run_queue(Manager *m) {
1411         Job *j;
1412         unsigned n = 0;
1413
1414         if (m->dispatching_run_queue)
1415                 return 0;
1416
1417         m->dispatching_run_queue = true;
1418
1419         while ((j = m->run_queue)) {
1420                 assert(j->installed);
1421                 assert(j->in_run_queue);
1422
1423                 job_run_and_invalidate(j);
1424                 n++;
1425         }
1426
1427         m->dispatching_run_queue = false;
1428         return n;
1429 }
1430
1431 unsigned manager_dispatch_dbus_queue(Manager *m) {
1432         Job *j;
1433         Meta *meta;
1434         unsigned n = 0;
1435
1436         assert(m);
1437
1438         if (m->dispatching_dbus_queue)
1439                 return 0;
1440
1441         m->dispatching_dbus_queue = true;
1442
1443         while ((meta = m->dbus_unit_queue)) {
1444                 assert(meta->in_dbus_queue);
1445
1446                 bus_unit_send_change_signal(UNIT(meta));
1447                 n++;
1448         }
1449
1450         while ((j = m->dbus_job_queue)) {
1451                 assert(j->in_dbus_queue);
1452
1453                 bus_job_send_change_signal(j);
1454                 n++;
1455         }
1456
1457         m->dispatching_dbus_queue = false;
1458         return n;
1459 }
1460
1461 static int manager_dispatch_sigchld(Manager *m) {
1462         assert(m);
1463
1464         for (;;) {
1465                 siginfo_t si;
1466                 Unit *u;
1467
1468                 zero(si);
1469
1470                 /* First we call waitd() for a PID and do not reap the
1471                  * zombie. That way we can still access /proc/$PID for
1472                  * it while it is a zombie. */
1473                 if (waitid(P_ALL, 0, &si, WEXITED|WNOHANG|WNOWAIT) < 0) {
1474
1475                         if (errno == ECHILD)
1476                                 break;
1477
1478                         if (errno == EINTR)
1479                                 continue;
1480
1481                         return -errno;
1482                 }
1483
1484                 if (si.si_pid <= 0)
1485                         break;
1486
1487                 if (si.si_code == CLD_EXITED || si.si_code == CLD_KILLED || si.si_code == CLD_DUMPED) {
1488                         char *name = NULL;
1489
1490                         get_process_name(si.si_pid, &name);
1491                         log_debug("Got SIGCHLD for process %llu (%s)", (unsigned long long) si.si_pid, strna(name));
1492                         free(name);
1493                 }
1494
1495                 /* And now, we actually reap the zombie. */
1496                 if (waitid(P_PID, si.si_pid, &si, WEXITED) < 0) {
1497                         if (errno == EINTR)
1498                                 continue;
1499
1500                         return -errno;
1501                 }
1502
1503                 if (si.si_code != CLD_EXITED && si.si_code != CLD_KILLED && si.si_code != CLD_DUMPED)
1504                         continue;
1505
1506                 log_debug("Child %llu died (code=%s, status=%i/%s)",
1507                           (long long unsigned) si.si_pid,
1508                           sigchld_code_to_string(si.si_code),
1509                           si.si_status,
1510                           strna(si.si_code == CLD_EXITED ? exit_status_to_string(si.si_status) : strsignal(si.si_status)));
1511
1512                 if (!(u = hashmap_remove(m->watch_pids, UINT32_TO_PTR(si.si_pid))))
1513                         continue;
1514
1515                 log_debug("Child %llu belongs to %s", (long long unsigned) si.si_pid, unit_id(u));
1516
1517                 UNIT_VTABLE(u)->sigchld_event(u, si.si_pid, si.si_code, si.si_status);
1518         }
1519
1520         return 0;
1521 }
1522
1523 static void manager_start_target(Manager *m, const char *name) {
1524         int r;
1525
1526         if ((r = manager_add_job_by_name(m, JOB_START, name, JOB_REPLACE, true, NULL)) < 0)
1527                 log_error("Failed to enqueue %s job: %s", name, strerror(-r));
1528 }
1529
1530 static int manager_process_signal_fd(Manager *m, bool *quit) {
1531         ssize_t n;
1532         struct signalfd_siginfo sfsi;
1533         bool sigchld = false;
1534
1535         assert(m);
1536
1537         for (;;) {
1538                 if ((n = read(m->signal_watch.fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) {
1539
1540                         if (n >= 0)
1541                                 return -EIO;
1542
1543                         if (errno == EAGAIN)
1544                                 break;
1545
1546                         return -errno;
1547                 }
1548
1549                 switch (sfsi.ssi_signo) {
1550
1551                 case SIGCHLD:
1552                         sigchld = true;
1553                         break;
1554
1555                 case SIGINT:
1556                 case SIGTERM:
1557
1558                         if (m->running_as == MANAGER_INIT) {
1559                                 manager_start_target(m, SPECIAL_CTRL_ALT_DEL_TARGET);
1560                                 break;
1561                         }
1562
1563                         *quit = true;
1564                         return 0;
1565
1566                 case SIGWINCH:
1567
1568                         if (m->running_as == MANAGER_INIT)
1569                                 manager_start_target(m, SPECIAL_KBREQUEST_TARGET);
1570
1571                         /* This is a nop on non-init */
1572                         break;
1573
1574                 case SIGPWR:
1575                         if (m->running_as == MANAGER_INIT)
1576                                 manager_start_target(m, SPECIAL_SIGPWR_TARGET);
1577
1578                         /* This is a nop on non-init */
1579                         break;
1580
1581                 case SIGUSR1:
1582                         manager_dump_units(m, stdout, "\t");
1583                         manager_dump_jobs(m, stdout, "\t");
1584                         break;
1585
1586                 default:
1587                         log_info("Got unhandled signal <%s>.", strsignal(sfsi.ssi_signo));
1588                 }
1589         }
1590
1591         if (sigchld)
1592                 return manager_dispatch_sigchld(m);
1593
1594         return 0;
1595 }
1596
1597 static int process_event(Manager *m, struct epoll_event *ev, bool *quit) {
1598         int r;
1599         Watch *w;
1600
1601         assert(m);
1602         assert(ev);
1603
1604         assert(w = ev->data.ptr);
1605
1606         switch (w->type) {
1607
1608         case WATCH_SIGNAL:
1609
1610                 /* An incoming signal? */
1611                 if (ev->events != EPOLLIN)
1612                         return -EINVAL;
1613
1614                 if ((r = manager_process_signal_fd(m, quit)) < 0)
1615                         return r;
1616
1617                 break;
1618
1619         case WATCH_FD:
1620
1621                 /* Some fd event, to be dispatched to the units */
1622                 UNIT_VTABLE(w->data.unit)->fd_event(w->data.unit, w->fd, ev->events, w);
1623                 break;
1624
1625         case WATCH_TIMER: {
1626                 uint64_t v;
1627                 ssize_t k;
1628
1629                 /* Some timer event, to be dispatched to the units */
1630                 if ((k = read(w->fd, &v, sizeof(v))) != sizeof(v)) {
1631
1632                         if (k < 0 && (errno == EINTR || errno == EAGAIN))
1633                                 break;
1634
1635                         return k < 0 ? -errno : -EIO;
1636                 }
1637
1638                 UNIT_VTABLE(w->data.unit)->timer_event(w->data.unit, v, w);
1639                 break;
1640         }
1641
1642         case WATCH_MOUNT:
1643                 /* Some mount table change, intended for the mount subsystem */
1644                 mount_fd_event(m, ev->events);
1645                 break;
1646
1647         case WATCH_UDEV:
1648                 /* Some notification from udev, intended for the device subsystem */
1649                 device_fd_event(m, ev->events);
1650                 break;
1651
1652         case WATCH_DBUS_WATCH:
1653                 bus_watch_event(m, w, ev->events);
1654                 break;
1655
1656         case WATCH_DBUS_TIMEOUT:
1657                 bus_timeout_event(m, w, ev->events);
1658                 break;
1659
1660         default:
1661                 assert_not_reached("Unknown epoll event type.");
1662         }
1663
1664         return 0;
1665 }
1666
1667 int manager_loop(Manager *m) {
1668         int r;
1669         bool quit = false;
1670
1671         RATELIMIT_DEFINE(rl, 1*USEC_PER_SEC, 1000);
1672
1673         assert(m);
1674
1675         do {
1676                 struct epoll_event event;
1677                 int n;
1678
1679                 if (!ratelimit_test(&rl)) {
1680                         /* Yay, something is going seriously wrong, pause a little */
1681                         log_warning("Looping too fast. Throttling execution a little.");
1682                         sleep(1);
1683                 }
1684
1685                 if (manager_dispatch_cleanup_queue(m) > 0)
1686                         continue;
1687
1688                 if (manager_dispatch_load_queue(m) > 0)
1689                         continue;
1690
1691                 if (manager_dispatch_run_queue(m) > 0)
1692                         continue;
1693
1694                 if (bus_dispatch(m) > 0)
1695                         continue;
1696
1697                 if (manager_dispatch_dbus_queue(m) > 0)
1698                         continue;
1699
1700                 if ((n = epoll_wait(m->epoll_fd, &event, 1, -1)) < 0) {
1701
1702                         if (errno == -EINTR)
1703                                 continue;
1704
1705                         return -errno;
1706                 }
1707
1708                 assert(n == 1);
1709
1710                 if ((r = process_event(m, &event, &quit)) < 0)
1711                         return r;
1712         } while (!quit);
1713
1714         return 0;
1715 }
1716
1717 int manager_get_unit_from_dbus_path(Manager *m, const char *s, Unit **_u) {
1718         char *n;
1719         Unit *u;
1720
1721         assert(m);
1722         assert(s);
1723         assert(_u);
1724
1725         if (!startswith(s, "/org/freedesktop/systemd1/unit/"))
1726                 return -EINVAL;
1727
1728         if (!(n = bus_path_unescape(s+31)))
1729                 return -ENOMEM;
1730
1731         u = manager_get_unit(m, n);
1732         free(n);
1733
1734         if (!u)
1735                 return -ENOENT;
1736
1737         *_u = u;
1738
1739         return 0;
1740 }
1741
1742 int manager_get_job_from_dbus_path(Manager *m, const char *s, Job **_j) {
1743         Job *j;
1744         unsigned id;
1745         int r;
1746
1747         assert(m);
1748         assert(s);
1749         assert(_j);
1750
1751         if (!startswith(s, "/org/freedesktop/systemd1/job/"))
1752                 return -EINVAL;
1753
1754         if ((r = safe_atou(s + 30, &id)) < 0)
1755                 return r;
1756
1757         if (!(j = manager_get_job(m, id)))
1758                 return -ENOENT;
1759
1760         *_j = j;
1761
1762         return 0;
1763 }
1764
1765 static bool manager_utmp_good(Manager *m) {
1766         int r;
1767
1768         assert(m);
1769
1770         if ((r = mount_path_is_mounted(m, _PATH_UTMPX)) <= 0) {
1771
1772                 if (r < 0)
1773                         log_warning("Failed to determine whether " _PATH_UTMPX " is mounted: %s", strerror(-r));
1774
1775                 return false;
1776         }
1777
1778         return true;
1779 }
1780
1781 void manager_write_utmp_reboot(Manager *m) {
1782         int r;
1783
1784         assert(m);
1785
1786         if (m->utmp_reboot_written)
1787                 return;
1788
1789         if (m->running_as != MANAGER_INIT)
1790                 return;
1791
1792         if (!manager_utmp_good(m))
1793                 return;
1794
1795         if ((r = utmp_put_reboot(m->boot_timestamp)) < 0) {
1796
1797                 if (r != -ENOENT && r != -EROFS)
1798                         log_warning("Failed to write utmp/wtmp: %s", strerror(-r));
1799
1800                 return;
1801         }
1802
1803         m->utmp_reboot_written = true;
1804 }
1805
1806 void manager_write_utmp_runlevel(Manager *m, Unit *u) {
1807         int runlevel, r;
1808
1809         assert(m);
1810         assert(u);
1811
1812         if (u->meta.type != UNIT_TARGET)
1813                 return;
1814
1815         if (m->running_as != MANAGER_INIT)
1816                 return;
1817
1818         if (!manager_utmp_good(m))
1819                 return;
1820
1821         if ((runlevel = target_get_runlevel(TARGET(u))) <= 0)
1822                 return;
1823
1824         if ((r = utmp_put_runlevel(0, runlevel, 0)) < 0) {
1825
1826                 if (r != -ENOENT && r != -EROFS)
1827                         log_warning("Failed to write utmp/wtmp: %s", strerror(-r));
1828         }
1829 }
1830
1831 static const char* const manager_running_as_table[_MANAGER_RUNNING_AS_MAX] = {
1832         [MANAGER_INIT] = "init",
1833         [MANAGER_SYSTEM] = "system",
1834         [MANAGER_SESSION] = "session"
1835 };
1836
1837 DEFINE_STRING_TABLE_LOOKUP(manager_running_as, ManagerRunningAs);