multipathd/main.c

   1 #include <unistd.h>
   2 #include <sys/stat.h>
   3 #include <libdevmapper.h>
   4 #include <wait.h>
   5 #include <sys/mman.h>
   6
   7 /*
   8  * libsysfs
   9  */
  10 #include <sysfs/libsysfs.h>
  11 #include <sysfs/dlist.h>
  12
  13 /*
  14  * libcheckers
  15  */
  16 #include <checkers.h>
  17 #include <path_state.h>
  18
  19 /*
  20  * libmultipath
  21  */
  22 #include <parser.h>
  23 #include <vector.h>
  24 #include <memory.h>
  25 #include <config.h>
  26 #include <callout.h>
  27 #include <util.h>
  28 #include <blacklist.h>
  29 #include <hwtable.h>
  30 #include <defaults.h>
  31 #include <structs.h>
  32 #include <dmparser.h>
  33 #include <devmapper.h>
  34 #include <dict.h>
  35 #include <discovery.h>
  36 #include <debug.h>
  37 #include <propsel.h>
  38 #include <uevent.h>
  39 #include <switchgroup.h>
  40 #include <path_state.h>
  41 #include <print.h>
  42
  43 #include "main.h"
  44 #include "pidfile.h"
  45 #include "uxlsnr.h"
  46 #include "uxclnt.h"
  47 #include "cli.h"
  48 #include "cli_handlers.h"
  49
  50 #define FILE_NAME_SIZE 256
  51 #define CMDSIZE 160
  52
  53 #define LOG_MSG(a,b) \
  54         if (strlen(b)) { \
  55                 condlog(a, "%s: %s", pp->dev_t, b); \
  56                 memset(b, 0, MAX_CHECKER_MSG_SIZE); \
  57         }
  58
  59 #ifdef LCKDBG
  60 #define lock(a) \
  61         fprintf(stderr, "%s:%s(%i) lock %p\n", __FILE__, __FUNCTION__, __LINE__, a); \
  62         pthread_mutex_lock(a)
  63 #define unlock(a) \
  64         fprintf(stderr, "%s:%s(%i) unlock %p\n", __FILE__, __FUNCTION__, __LINE__, a); \
  65         pthread_mutex_unlock(a)
  66 #define lock_cleanup_pop(a) \
  67         fprintf(stderr, "%s:%s(%i) unlock %p\n", __FILE__, __FUNCTION__, __LINE__, a); \
  68         pthread_cleanup_pop(1);
  69 #else
  70 #define lock(a) pthread_mutex_lock(a)
  71 #define unlock(a) pthread_mutex_unlock(a)
  72 #define lock_cleanup_pop(a) pthread_cleanup_pop(1);
  73 #endif
  74
  75 pthread_cond_t exit_cond = PTHREAD_COND_INITIALIZER;
  76 pthread_mutex_t exit_mutex = PTHREAD_MUTEX_INITIALIZER;
  77
  78 /*
  79  * structs
  80  */
  81 struct event_thread {
  82         struct dm_task *dmt;
  83         pthread_t thread;
  84         int event_nr;
  85         char mapname[WWID_SIZE];
  86         struct vectors *vecs;
  87 };
  88
  89 static struct event_thread *
  90 alloc_waiter (void)
  91 {
  92
  93         struct event_thread * wp;
  94
  95         wp = (struct event_thread *)MALLOC(sizeof(struct event_thread));
  96
  97         return wp;
  98 }
  99
 100 static void
 101 free_waiter (void * data)
 102 {
 103         struct event_thread * wp = (struct event_thread *)data;
 104
 105         if (wp->dmt)
 106                 dm_task_destroy(wp->dmt);
 107         FREE(wp);
 108 }
 109
 110 static void
 111 stop_waiter_thread (struct multipath * mpp, struct vectors * vecs)
 112 {
 113         struct event_thread * wp = (struct event_thread *)mpp->waiter;
 114         pthread_t thread;
 115
 116         if (!wp) {
 117                 condlog(3, "%s: no waiter thread", mpp->alias);
 118                 return;
 119         }
 120         thread = wp->thread;
 121
 122         if (!wp) {
 123                 condlog(3, "%s: thread not started", mpp->alias);
 124                 return;
 125         }
 126         condlog(2, "%s: stop event checker thread", wp->mapname);
 127         pthread_kill(thread, SIGHUP);
 128 }
 129
 130 static void
 131 cleanup_lock (void * data)
 132 {
 133         pthread_mutex_unlock((pthread_mutex_t *)data);
 134 }
 135
 136 static void
 137 adopt_paths (struct vectors * vecs, struct multipath * mpp)
 138 {
 139         int i;
 140         struct path * pp;
 141
 142         if (!mpp)
 143                 return;
 144
 145         vector_foreach_slot (vecs->pathvec, pp, i) {
 146                 if (!strncmp(mpp->wwid, pp->wwid, WWID_SIZE)) {
 147                         condlog(4, "%s ownership set", pp->dev_t);
 148                         pp->mpp = mpp;
 149                 }
 150         }
 151 }
 152
 153 static void
 154 orphan_path (struct path * pp)
 155 {
 156         pp->mpp = NULL;
 157         pp->checkfn = NULL;
 158         pp->dmstate = PSTATE_UNDEF;
 159         pp->checker_context = NULL;
 160         pp->getuid = NULL;
 161         pp->getprio = NULL;
 162
 163         if (pp->fd >= 0)
 164                 close(pp->fd);
 165
 166         pp->fd = -1;
 167 }
 168
 169 static void
 170 orphan_paths (struct vectors * vecs, struct multipath * mpp)
 171 {
 172         int i;
 173         struct path * pp;
 174
 175         vector_foreach_slot (vecs->pathvec, pp, i) {
 176                 if (pp->mpp == mpp) {
 177                         condlog(4, "%s is orphaned", pp->dev_t);
 178                         orphan_path(pp);
 179                 }
 180         }
 181 }
 182
 183 static int
 184 update_multipath_table (struct multipath *mpp, vector pathvec)
 185 {
 186         if (!mpp)
 187                 return 1;
 188
 189         if (dm_get_map(mpp->alias, &mpp->size, mpp->params))
 190                 return 1;
 191
 192         if (disassemble_map(pathvec, mpp->params, mpp))
 193                 return 1;
 194
 195         return 0;
 196 }
 197
 198 static int
 199 update_multipath_status (struct multipath *mpp)
 200 {
 201         if (!mpp)
 202                 return 1;
 203
 204         if(dm_get_status(mpp->alias, mpp->status))
 205                 return 1;
 206
 207         if (disassemble_status(mpp->status, mpp))
 208                 return 1;
 209
 210         return 0;
 211 }
 212
 213 static int
 214 update_multipath_strings (struct multipath *mpp, vector pathvec)
 215 {
 216         if (mpp->selector) {
 217                 FREE(mpp->selector);
 218                 mpp->selector = NULL;
 219         }
 220
 221         if (mpp->features) {
 222                 FREE(mpp->features);
 223                 mpp->features = NULL;
 224         }
 225
 226         if (mpp->hwhandler) {
 227                 FREE(mpp->hwhandler);
 228                 mpp->hwhandler = NULL;
 229         }
 230
 231         free_pgvec(mpp->pg, KEEP_PATHS);
 232         mpp->pg = NULL;
 233
 234         if (update_multipath_table(mpp, pathvec))
 235                 return 1;
 236
 237         if (update_multipath_status(mpp))
 238                 return 1;
 239
 240         return 0;
 241 }
 242
 243 static void
 244 set_multipath_wwid (struct multipath * mpp)
 245 {
 246         if (mpp->wwid)
 247                 return;
 248
 249         dm_get_uuid(mpp->alias, mpp->wwid);
 250 }
 251
 252 static int
 253 pathcount (struct multipath *mpp, int state)
 254 {
 255         struct pathgroup *pgp;
 256         struct path *pp;
 257         int i, j;
 258         int count = 0;
 259
 260         vector_foreach_slot (mpp->pg, pgp, i)
 261                 vector_foreach_slot (pgp->paths, pp, j)
 262                         if (pp->state == state)
 263                                 count++;
 264         return count;
 265 }
 266
 267 /*
 268  * mpp->no_path_retry:
 269  *   -2 (QUEUE) : queue_if_no_path enabled, never turned off
 270  *   -1 (FAIL)  : fail_if_no_path
 271  *    0 (UNDEF) : nothing
 272  *   >0         : queue_if_no_path enabled, turned off after polling n times
 273  */
 274 static void
 275 update_queue_mode_del_path(struct multipath *mpp)
 276 {
 277         if (--mpp->nr_active == 0 && mpp->no_path_retry > 0) {
 278                 /*
 279                  * Enter retry mode.
 280                  * meaning of +1: retry_tick may be decremented in
 281                  *                checkerloop before starting retry.
 282                  */
 283                 mpp->retry_tick = mpp->no_path_retry * conf->checkint + 1;
 284                 condlog(1, "%s: Entering recovery mode: max_retries=%d",
 285                         mpp->alias, mpp->no_path_retry);
 286         }
 287         condlog(2, "%s: remaining active paths: %d", mpp->alias, mpp->nr_active);
 288 }
 289
 290 static void
 291 update_queue_mode_add_path(struct multipath *mpp)
 292 {
 293         if (mpp->nr_active++ == 0 && mpp->no_path_retry > 0) {
 294                 /* come back to normal mode from retry mode */
 295                 mpp->retry_tick = 0;
 296                 dm_queue_if_no_path(mpp->alias, 1);
 297                 condlog(2, "%s: queue_if_no_path enabled", mpp->alias);
 298                 condlog(1, "%s: Recovered to normal mode", mpp->alias);
 299         }
 300         condlog(2, "%s: remaining active paths: %d", mpp->alias, mpp->nr_active);
 301 }
 302
 303 static void
 304 set_no_path_retry(struct multipath *mpp)
 305 {
 306         mpp->retry_tick = 0;
 307         mpp->nr_active = pathcount(mpp, PATH_UP);
 308         select_no_path_retry(mpp);
 309
 310         switch (mpp->no_path_retry) {
 311         case NO_PATH_RETRY_UNDEF:
 312                 break;
 313         case NO_PATH_RETRY_FAIL:
 314                 dm_queue_if_no_path(mpp->alias, 0);
 315                 break;
 316         case NO_PATH_RETRY_QUEUE:
 317                 dm_queue_if_no_path(mpp->alias, 1);
 318                 break;
 319         default:
 320                 dm_queue_if_no_path(mpp->alias, 1);
 321                 if (mpp->nr_active == 0) {
 322                         /* Enter retry mode */
 323                         mpp->retry_tick = mpp->no_path_retry * conf->checkint;
 324                         condlog(1, "%s: Entering recovery mode: max_retries=%d",
 325                                 mpp->alias, mpp->no_path_retry);
 326                 }
 327                 break;
 328         }
 329 }
 330
 331 static struct hwentry *
 332 extract_hwe_from_path(struct multipath * mpp)
 333 {
 334         struct path * pp;
 335         struct pathgroup * pgp;
 336
 337         pgp = VECTOR_SLOT(mpp->pg, 0);
 338         pp = VECTOR_SLOT(pgp->paths, 0);
 339
 340         return pp->hwe;
 341 }
 342
 343 static void
 344 remove_map (struct multipath * mpp, struct vectors * vecs)
 345 {
 346         int i;
 347
 348         stop_waiter_thread(mpp, vecs);
 349
 350         /*
 351          * clear references to this map
 352          */
 353         orphan_paths(vecs, mpp);
 354
 355         /*
 356          * purge the multipath vector
 357          */
 358         i = find_slot(vecs->mpvec, (void *)mpp);
 359         vector_del_slot(vecs->mpvec, i);
 360
 361         /*
 362          * final free
 363          */
 364         free_multipath(mpp, KEEP_PATHS);
 365         mpp = NULL;
 366 }
 367
 368 static void
 369 remove_maps (struct vectors * vecs)
 370 {
 371         int i;
 372         struct multipath * mpp;
 373
 374         vector_foreach_slot (vecs->mpvec, mpp, i) {
 375                 remove_map(mpp, vecs);
 376                 i--;
 377         }
 378
 379         vector_free(vecs->mpvec);
 380         vecs->mpvec = NULL;
 381 }
 382
 383 static int
 384 setup_multipath (struct vectors * vecs, struct multipath * mpp)
 385 {
 386         set_multipath_wwid(mpp);
 387         mpp->mpe = find_mpe(mpp->wwid);
 388         condlog(4, "discovered map %s", mpp->alias);
 389
 390         if (update_multipath_strings(mpp, vecs->pathvec))
 391                 goto out;
 392
 393         adopt_paths(vecs, mpp);
 394         select_pgfailback(mpp);
 395         mpp->hwe = extract_hwe_from_path(mpp);
 396         set_no_path_retry(mpp);
 397
 398         return 0;
 399 out:
 400         condlog(0, "%s: failed to setup multipath", mpp->alias);
 401         remove_map(mpp, vecs);
 402         return 1;
 403 }
 404
 405 static int
 406 need_switch_pathgroup (struct multipath * mpp, int refresh)
 407 {
 408         struct pathgroup * pgp;
 409         struct path * pp;
 410         int i, j;
 411
 412         if (!mpp || mpp->pgfailback == -FAILBACK_MANUAL)
 413                 return 0;
 414
 415         /*
 416          * Refresh path priority values
 417          */
 418         if (refresh)
 419                 vector_foreach_slot (mpp->pg, pgp, i)
 420                         vector_foreach_slot (pgp->paths, pp, j)
 421                                 pathinfo(pp, conf->hwtable, DI_PRIO);
 422
 423         select_path_group(mpp); /* sets mpp->nextpg */
 424         pgp = VECTOR_SLOT(mpp->pg, mpp->nextpg - 1);
 425
 426         if (pgp && pgp->status != PGSTATE_ACTIVE)
 427                 return 1;
 428
 429         return 0;
 430 }
 431
 432 static void
 433 switch_pathgroup (struct multipath * mpp)
 434 {
 435         struct pathgroup * pgp;
 436
 437         pgp = VECTOR_SLOT(mpp->pg, mpp->nextpg - 1);
 438
 439         if (pgp && pgp->status != PGSTATE_ACTIVE) {
 440                 dm_switchgroup(mpp->alias, mpp->nextpg);
 441                 condlog(2, "%s: switch to path group #%i",
 442                          mpp->alias, mpp->nextpg);
 443         }
 444 }
 445
 446 static int
 447 update_multipath (struct vectors *vecs, char *mapname)
 448 {
 449         struct multipath *mpp;
 450         struct pathgroup  *pgp;
 451         struct path *pp;
 452         int i, j;
 453         int r = 1;
 454
 455         mpp = find_mp(vecs->mpvec, mapname);
 456
 457         if (!mpp)
 458                 goto out;
 459
 460         free_pgvec(mpp->pg, KEEP_PATHS);
 461         mpp->pg = NULL;
 462
 463         if (setup_multipath(vecs, mpp))
 464                 goto out; /* mpp freed in setup_multipath */
 465
 466         /*
 467          * compare checkers states with DM states
 468          */
 469         vector_foreach_slot (mpp->pg, pgp, i) {
 470                 vector_foreach_slot (pgp->paths, pp, j) {
 471                         if (pp->dmstate != PSTATE_FAILED)
 472                                 continue;
 473
 474                         if (pp->state != PATH_DOWN) {
 475                                 condlog(2, "%s: mark as failed", pp->dev_t);
 476                                 pp->state = PATH_DOWN;
 477                                 update_queue_mode_del_path(mpp);
 478
 479                                 /*
 480                                  * if opportune,
 481                                  * schedule the next check earlier
 482                                  */
 483                                 if (pp->tick > conf->checkint)
 484                                         pp->tick = conf->checkint;
 485                         }
 486                 }
 487         }
 488         r = 0;
 489 out:
 490         if (r)
 491                 condlog(0, "failed to update multipath");
 492
 493         return r;
 494 }
 495
 496 static sigset_t unblock_sighup(void)
 497 {
 498         sigset_t set, old;
 499
 500         sigemptyset(&set);
 501         sigaddset(&set, SIGHUP);
 502         pthread_sigmask(SIG_UNBLOCK, &set, &old);
 503         return old;
 504 }
 505
 506 /*
 507  * returns the reschedule delay
 508  * negative means *stop*
 509  */
 510 static int
 511 waiteventloop (struct event_thread * waiter)
 512 {
 513         sigset_t set;
 514         int event_nr;
 515         int r;
 516
 517         if (!waiter->event_nr)
 518                 waiter->event_nr = dm_geteventnr(waiter->mapname);
 519
 520         if (!(waiter->dmt = dm_task_create(DM_DEVICE_WAITEVENT)))
 521                 return 1;
 522
 523         if (!dm_task_set_name(waiter->dmt, waiter->mapname)) {
 524                 dm_task_destroy(waiter->dmt);
 525                 return 1;
 526         }
 527
 528         if (waiter->event_nr && !dm_task_set_event_nr(waiter->dmt,
 529                                                       waiter->event_nr)) {
 530                 dm_task_destroy(waiter->dmt);
 531                 return 1;
 532         }
 533
 534         dm_task_no_open_count(waiter->dmt);
 535
 536         /* accept wait interruption */
 537         set = unblock_sighup();
 538
 539         /* interruption spits messages */
 540         dm_shut_log();
 541
 542         /* wait */
 543         r = dm_task_run(waiter->dmt);
 544
 545         /* wait is over : event or interrupt */
 546         pthread_sigmask(SIG_SETMASK, &set, NULL);
 547         //dm_restore_log();
 548
 549         if (!r) /* wait interrupted by signal */
 550                 return -1;
 551
 552         dm_task_destroy(waiter->dmt);
 553         waiter->dmt = NULL;
 554         waiter->event_nr++;
 555
 556         /*
 557          * upon event ...
 558          */
 559         while (1) {
 560                 condlog(3, "%s: devmap event #%i",
 561                                 waiter->mapname, waiter->event_nr);
 562
 563                 /*
 564                  * event might be :
 565                  *
 566                  * 1) a table reload, which means our mpp structure is
 567                  *    obsolete : refresh it through update_multipath()
 568                  * 2) a path failed by DM : mark as such through
 569                  *    update_multipath()
 570                  * 3) map has gone away : stop the thread.
 571                  * 4) a path reinstate : nothing to do
 572                  * 5) a switch group : nothing to do
 573                  */
 574                 pthread_cleanup_push(cleanup_lock, waiter->vecs->lock);
 575                 lock(waiter->vecs->lock);
 576                 r = update_multipath(waiter->vecs, waiter->mapname);
 577                 lock_cleanup_pop(waiter->vecs->lock);
 578
 579                 if (r)
 580                         return -1; /* stop the thread */
 581
 582                 event_nr = dm_geteventnr(waiter->mapname);
 583
 584                 if (waiter->event_nr == event_nr)
 585                         return 1; /* upon problem reschedule 1s later */
 586
 587                 waiter->event_nr = event_nr;
 588         }
 589         return -1; /* never reach there */
 590 }
 591
 592 static void *
 593 waitevent (void * et)
 594 {
 595         int r;
 596         struct event_thread *waiter;
 597
 598         mlockall(MCL_CURRENT | MCL_FUTURE);
 599
 600         waiter = (struct event_thread *)et;
 601         pthread_cleanup_push(free_waiter, et);
 602
 603         while (1) {
 604                 r = waiteventloop(waiter);
 605
 606                 if (r < 0)
 607                         break;
 608
 609                 sleep(r);
 610         }
 611
 612         pthread_cleanup_pop(1);
 613         return NULL;
 614 }
 615
 616 static int
 617 start_waiter_thread (struct multipath * mpp, struct vectors * vecs)
 618 {
 619         pthread_attr_t attr;
 620         struct event_thread * wp;
 621
 622         if (!mpp)
 623                 return 0;
 624
 625         if (pthread_attr_init(&attr))
 626                 goto out;
 627
 628         pthread_attr_setstacksize(&attr, 32 * 1024);
 629         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 630
 631         wp = alloc_waiter();
 632
 633         if (!wp)
 634                 goto out;
 635
 636         mpp->waiter = (void *)wp;
 637         strncpy(wp->mapname, mpp->alias, WWID_SIZE);
 638         wp->vecs = vecs;
 639
 640         if (pthread_create(&wp->thread, &attr, waitevent, wp)) {
 641                 condlog(0, "%s: cannot create event checker", wp->mapname);
 642                 goto out1;
 643         }
 644         condlog(2, "%s: event checker started", wp->mapname);
 645
 646         return 0;
 647 out1:
 648         free_waiter(wp);
 649         mpp->waiter = NULL;
 650 out:
 651         condlog(0, "failed to start waiter thread");
 652         return 1;
 653 }
 654
 655 int
 656 uev_add_map (char * devname, struct vectors * vecs)
 657 {
 658         int major, minor;
 659         char dev_t[BLK_DEV_SIZE];
 660         char * alias;
 661         struct multipath * mpp;
 662
 663         if (sysfs_get_dev(sysfs_path, devname, dev_t, BLK_DEV_SIZE))
 664                 return 1;
 665
 666         if (sscanf(dev_t, "%d:%d", &major, &minor) != 2)
 667                 return 1;
 668
 669         alias = dm_mapname(major, minor);
 670
 671         if (!alias)
 672                 return 1;
 673
 674         if (!dm_type(alias, DEFAULT_TARGET)) {
 675                 condlog(4, "%s: not a multipath map", alias);
 676                 FREE(alias);
 677                 return 0;
 678         }
 679
 680         mpp = find_mp(vecs->mpvec, alias);
 681
 682         if (mpp) {
 683                 /*
 684                  * this should not happen,
 685                  * we missed a remove map event (not sent ?)
 686                  */
 687                 condlog(2, "%s: already registered", alias);
 688                 remove_map(mpp, vecs);
 689         }
 690
 691         /*
 692          * now we can allocate
 693          */
 694         mpp = alloc_multipath();
 695
 696         if (!mpp)
 697                 return 1;
 698
 699         mpp->minor = minor;
 700         mpp->alias = alias;
 701
 702         if (setup_multipath(vecs, mpp))
 703                 return 1; /* mpp freed in setup_multipath */
 704
 705         if (!vector_alloc_slot(vecs->mpvec))
 706                 goto out;
 707
 708         vector_set_slot(vecs->mpvec, mpp);
 709         adopt_paths(vecs, mpp);
 710
 711         if (start_waiter_thread(mpp, vecs))
 712                 goto out;
 713
 714         return 0;
 715 out:
 716         condlog(2, "%s: add devmap failed", mpp->alias);
 717         remove_map(mpp, vecs);
 718         return 1;
 719 }
 720
 721 int
 722 uev_remove_map (char * devname, struct vectors * vecs)
 723 {
 724         int minor;
 725         struct multipath * mpp;
 726
 727         if (sscanf(devname, "dm-%d", &minor) != 1)
 728                 return 1;
 729
 730         mpp = find_mp_by_minor(vecs->mpvec, minor);
 731
 732         if (!mpp) {
 733                 condlog(3, "%s: devmap not registered, can't remove",
 734                         devname);
 735                 return 0;
 736         }
 737
 738         condlog(2, "remove %s devmap", mpp->alias);
 739         remove_map(mpp, vecs);
 740
 741         return 0;
 742 }
 743
 744 int
 745 uev_add_path (char * devname, struct vectors * vecs)
 746 {
 747         struct path * pp;
 748
 749         pp = find_path_by_dev(vecs->pathvec, devname);
 750
 751         if (pp) {
 752                 condlog(3, "%s: already in pathvec");
 753                 return 1;
 754         }
 755         pp = store_pathinfo(vecs->pathvec, conf->hwtable,
 756                        devname, DI_SYSFS | DI_WWID);
 757
 758         if (!pp) {
 759                 condlog(0, "%s: failed to store path info", devname);
 760                 return 1;
 761         }
 762
 763         condlog(2, "%s: path checker registered", devname);
 764         pp->mpp = find_mp_by_wwid(vecs->mpvec, pp->wwid);
 765
 766         if (pp->mpp) {
 767                 condlog(4, "%s: ownership set to %s",
 768                                 pp->dev_t, pp->mpp->alias);
 769         } else {
 770                 condlog(4, "%s: orphaned", pp->dev_t);
 771                 orphan_path(pp);
 772         }
 773
 774         return 0;
 775 }
 776
 777 int
 778 uev_remove_path (char * devname, struct vectors * vecs)
 779 {
 780         int i;
 781         struct path * pp;
 782
 783         pp = find_path_by_dev(vecs->pathvec, devname);
 784
 785         if (!pp) {
 786                 condlog(3, "%s: not in pathvec");
 787                 return 1;
 788         }
 789
 790         if (pp->mpp && pp->state == PATH_UP)
 791                 update_queue_mode_del_path(pp->mpp);
 792
 793         condlog(2, "remove %s path checker", devname);
 794         i = find_slot(vecs->pathvec, (void *)pp);
 795         vector_del_slot(vecs->pathvec, i);
 796         free_path(pp);
 797
 798         return 0;
 799 }
 800
 801 int
 802 show_paths (char ** r, int * len, struct vectors * vecs)
 803 {
 804         int i;
 805         struct path * pp;
 806         char * c;
 807         char * reply;
 808         struct path_layout pl;
 809
 810         get_path_layout(&pl, vecs->pathvec);
 811         reply = MALLOC(MAX_REPLY_LEN);
 812
 813         if (!reply)
 814                 return 1;
 815
 816         c = reply;
 817
 818         if (VECTOR_SIZE(vecs->pathvec) > 0)
 819                 c += snprint_path_header(c, reply + MAX_REPLY_LEN - c,
 820                                          PRINT_PATH_CHECKER, &pl);
 821
 822         vector_foreach_slot(vecs->pathvec, pp, i)
 823                 c += snprint_path(c, reply + MAX_REPLY_LEN - c,
 824                                   PRINT_PATH_CHECKER, pp, &pl);
 825
 826         *r = reply;
 827         *len = (int)(c - reply + 1);
 828         return 0;
 829 }
 830
 831 int
 832 show_maps (char ** r, int *len, struct vectors * vecs)
 833 {
 834         int i;
 835         struct multipath * mpp;
 836         char * c;
 837         char * reply;
 838         struct map_layout ml;
 839
 840         get_map_layout(&ml, vecs->mpvec);
 841         reply = MALLOC(MAX_REPLY_LEN);
 842
 843         if (!reply)
 844                 return 1;
 845
 846         c = reply;
 847         if (VECTOR_SIZE(vecs->mpvec) > 0)
 848                 c += snprint_map_header(c, reply + MAX_REPLY_LEN - c,
 849                                         PRINT_MAP_FAILBACK, &ml);
 850
 851         vector_foreach_slot(vecs->mpvec, mpp, i)
 852                 c += snprint_map(c, reply + MAX_REPLY_LEN - c,
 853                                  PRINT_MAP_FAILBACK, mpp, &ml);
 854
 855         *r = reply;
 856         *len = (int)(c - reply + 1);
 857         return 0;
 858 }
 859
 860 int
 861 dump_pathvec (char ** r, int * len, struct vectors * vecs)
 862 {
 863         int i;
 864         struct path * pp;
 865         char * reply;
 866         char * p;
 867
 868         *len = VECTOR_SIZE(vecs->pathvec) * sizeof(struct path);
 869         reply = (char *)MALLOC(*len);
 870         *r = reply;
 871
 872         if (!reply)
 873                 return 1;
 874
 875         p = reply;
 876
 877         vector_foreach_slot (vecs->pathvec, pp, i) {
 878                 memcpy((void *)p, pp, sizeof(struct path));
 879                 p += sizeof(struct path);
 880         }
 881
 882         /* return negative to hint caller not to add "ok" to the dump */
 883         return -1;
 884 }
 885
 886 static int
 887 map_discovery (struct vectors * vecs)
 888 {
 889         int i;
 890         struct multipath * mpp;
 891
 892         if (dm_get_maps(vecs->mpvec, "multipath"))
 893                 return 1;
 894
 895         vector_foreach_slot (vecs->mpvec, mpp, i) {
 896                 if (setup_multipath(vecs, mpp))
 897                         return 1;
 898                 mpp->minor = dm_get_minor(mpp->alias);
 899                 start_waiter_thread(mpp, vecs);
 900         }
 901
 902         return 0;
 903 }
 904
 905 int
 906 reconfigure (struct vectors * vecs)
 907 {
 908         struct config * old = conf;
 909         struct multipath * mpp;
 910         struct path * pp;
 911         int i;
 912
 913         conf = NULL;
 914
 915         if (load_config(DEFAULT_CONFIGFILE)) {
 916                 conf = old;
 917                 condlog(2, "reconfigure failed, continue with old config");
 918                 return 1;
 919         }
 920         conf->verbosity = old->verbosity;
 921         free_config(old);
 922
 923         vector_foreach_slot (vecs->mpvec, mpp, i) {
 924                 mpp->mpe = find_mpe(mpp->wwid);
 925                 mpp->hwe = extract_hwe_from_path(mpp);
 926                 adopt_paths(vecs, mpp);
 927                 set_no_path_retry(mpp);
 928         }
 929         vector_foreach_slot (vecs->pathvec, pp, i) {
 930                 select_checkfn(pp);
 931                 select_getuid(pp);
 932                 select_getprio(pp);
 933         }
 934         condlog(2, "reconfigured");
 935         return 0;
 936 }
 937
 938 int
 939 uxsock_trigger (char * str, char ** reply, int * len, void * trigger_data)
 940 {
 941         struct vectors * vecs;
 942         int r;
 943
 944         *reply = NULL;
 945         *len = 0;
 946         vecs = (struct vectors *)trigger_data;
 947
 948         pthread_cleanup_push(cleanup_lock, vecs->lock);
 949         lock(vecs->lock);
 950
 951         r = parse_cmd(str, reply, len, vecs);
 952
 953         if (r > 0) {
 954                 *reply = STRDUP("fail\n");
 955                 *len = strlen(*reply) + 1;
 956                 r = 1;
 957         }
 958         else if (!r && *len == 0) {
 959                 *reply = STRDUP("ok\n");
 960                 *len = strlen(*reply) + 1;
 961                 r = 0;
 962         }
 963         /* else if (r < 0) leave *reply alone */
 964
 965         lock_cleanup_pop(vecs->lock);
 966         return r;
 967 }
 968
 969 static int
 970 uev_discard(char * devpath)
 971 {
 972         char a[10], b[10];
 973
 974         /*
 975          * keep only block devices, discard partitions
 976          */
 977         if (sscanf(devpath, "/block/%10s", a) != 1 ||
 978             sscanf(devpath, "/block/%10[^/]/%10s", a, b) == 2) {
 979                 condlog(4, "discard event on %s", devpath);
 980                 return 1;
 981         }
 982         return 0;
 983 }
 984
 985 int
 986 uev_trigger (struct uevent * uev, void * trigger_data)
 987 {
 988         int r = 0;
 989         char devname[32];
 990         struct vectors * vecs;
 991
 992         vecs = (struct vectors *)trigger_data;
 993
 994         if (uev_discard(uev->devpath))
 995                 goto out;
 996
 997         basename(uev->devpath, devname);
 998         lock(vecs->lock);
 999
1000         /*
1001          * device map add/remove event
1002          */
1003         if (!strncmp(devname, "dm-", 3)) {
1004                 if (!strncmp(uev->action, "add", 3)) {
1005                         r = uev_add_map(devname, vecs);
1006                         goto out;
1007                 }
1008 #if 0
1009                 if (!strncmp(uev->action, "remove", 6)) {
1010                         r = uev_remove_map(devname, vecs);
1011                         goto out;
1012                 }
1013 #endif
1014                 goto out;
1015         }
1016
1017         /*
1018          * path add/remove event
1019          */
1020         if (blacklist(conf->blist, devname))
1021                 goto out;
1022
1023         if (!strncmp(uev->action, "add", 3)) {
1024                 r = uev_add_path(devname, vecs);
1025                 goto out;
1026         }
1027         if (!strncmp(uev->action, "remove", 6)) {
1028                 r = uev_remove_path(devname, vecs);
1029                 goto out;
1030         }
1031
1032 out:
1033         unlock(vecs->lock);
1034         return r;
1035 }
1036
1037 static void *
1038 ueventloop (void * ap)
1039 {
1040         if (uevent_listen(&uev_trigger, ap))
1041                 fprintf(stderr, "error starting uevent listener");
1042
1043         return NULL;
1044 }
1045
1046 static void *
1047 uxlsnrloop (void * ap)
1048 {
1049         if (load_keys())
1050                 return NULL;
1051
1052         if (alloc_handlers())
1053                 return NULL;
1054
1055         add_handler(LIST+PATHS, cli_list_paths);
1056         add_handler(LIST+MAPS, cli_list_maps);
1057         add_handler(ADD+PATH, cli_add_path);
1058         add_handler(DEL+PATH, cli_del_path);
1059         add_handler(ADD+MAP, cli_add_map);
1060         add_handler(DEL+MAP, cli_del_map);
1061         add_handler(SWITCH+MAP+GROUP, cli_switch_group);
1062         add_handler(DUMP+PATHVEC, cli_dump_pathvec);
1063         add_handler(RECONFIGURE, cli_reconfigure);
1064
1065         uxsock_listen(&uxsock_trigger, ap);
1066
1067         return NULL;
1068 }
1069
1070 static int
1071 exit_daemon (int status)
1072 {
1073         if (status != 0)
1074                 fprintf(stderr, "bad exit status. see daemon.log\n");
1075
1076         condlog(3, "unlink pidfile");
1077         unlink(DEFAULT_PIDFILE);
1078
1079         lock(&exit_mutex);
1080         pthread_cond_signal(&exit_cond);
1081         unlock(&exit_mutex);
1082
1083         return status;
1084 }
1085
1086 static void
1087 fail_path (struct path * pp)
1088 {
1089         if (!pp->mpp)
1090                 return;
1091
1092         condlog(2, "checker failed path %s in map %s",
1093                  pp->dev_t, pp->mpp->alias);
1094
1095         dm_fail_path(pp->mpp->alias, pp->dev_t);
1096         update_queue_mode_del_path(pp->mpp);
1097 }
1098
1099 /*
1100  * caller must have locked the path list before calling that function
1101  */
1102 static void
1103 reinstate_path (struct path * pp)
1104 {
1105         if (!pp->mpp)
1106                 return;
1107
1108         if (dm_reinstate(pp->mpp->alias, pp->dev_t))
1109                 condlog(0, "%s: reinstate failed", pp->dev_t);
1110         else {
1111                 condlog(2, "%s: reinstated", pp->dev_t);
1112                 update_queue_mode_add_path(pp->mpp);
1113         }
1114 }
1115
1116 static void
1117 enable_group(struct path * pp)
1118 {
1119         struct pathgroup * pgp;
1120
1121         /*
1122          * if path is added through uev_add_path, pgindex can be unset.
1123          * next update_strings() will set it, upon map reload event.
1124          *
1125          * we can safely return here, because upon map reload, all
1126          * PG will be enabled.
1127          */
1128         if (!pp->pgindex)
1129                 return;
1130
1131         pgp = VECTOR_SLOT(pp->mpp->pg, pp->pgindex - 1);
1132
1133         if (pgp->status == PGSTATE_DISABLED) {
1134                 condlog(2, "%s: enable group #%i", pp->mpp->alias, pp->pgindex);
1135                 dm_enablegroup(pp->mpp->alias, pp->pgindex);
1136         }
1137 }
1138
1139 static void
1140 mpvec_garbage_collector (struct vectors * vecs)
1141 {
1142         struct multipath * mpp;
1143         int i;
1144
1145         vector_foreach_slot (vecs->mpvec, mpp, i) {
1146                 if (mpp && mpp->alias && !dm_map_present(mpp->alias)) {
1147                         condlog(2, "%s: remove dead map", mpp->alias);
1148                         remove_map(mpp, vecs);
1149                         i--;
1150                 }
1151         }
1152 }
1153
1154 static void
1155 defered_failback_tick (vector mpvec)
1156 {
1157         struct multipath * mpp;
1158         int i;
1159
1160         vector_foreach_slot (mpvec, mpp, i) {
1161                 /*
1162                  * defered failback getting sooner
1163                  */
1164                 if (mpp->pgfailback > 0 && mpp->failback_tick > 0) {
1165                         mpp->failback_tick--;
1166
1167                         if (!mpp->failback_tick && need_switch_pathgroup(mpp, 1))
1168                                 switch_pathgroup(mpp);
1169                 }
1170         }
1171 }
1172
1173 static void
1174 retry_count_tick(vector mpvec)
1175 {
1176         struct multipath *mpp;
1177         int i;
1178
1179         vector_foreach_slot (mpvec, mpp, i) {
1180                 if (mpp->retry_tick) {
1181                         condlog(4, "%s: Retrying.. No active path", mpp->alias);
1182                         if(--mpp->retry_tick == 0) {
1183                                 dm_queue_if_no_path(mpp->alias, 0);
1184                                 condlog(2, "%s: Disable queueing", mpp->alias);
1185                         }
1186                 }
1187         }
1188 }
1189
1190 static void *
1191 checkerloop (void *ap)
1192 {
1193         struct vectors *vecs;
1194         struct path *pp;
1195         int i, count = 0;
1196         int newstate;
1197         char checker_msg[MAX_CHECKER_MSG_SIZE];
1198
1199         mlockall(MCL_CURRENT | MCL_FUTURE);
1200
1201         memset(checker_msg, 0, MAX_CHECKER_MSG_SIZE);
1202         vecs = (struct vectors *)ap;
1203
1204         condlog(2, "path checkers start up");
1205
1206         /*
1207          * init the path check interval
1208          */
1209         vector_foreach_slot (vecs->pathvec, pp, i) {
1210                 pp->checkint = conf->checkint;
1211         }
1212
1213         while (1) {
1214                 pthread_cleanup_push(cleanup_lock, vecs->lock);
1215                 lock(vecs->lock);
1216                 condlog(4, "tick");
1217
1218                 vector_foreach_slot (vecs->pathvec, pp, i) {
1219                         if (!pp->mpp)
1220                                 continue;
1221
1222                         if (pp->tick && --pp->tick)
1223                                 continue; /* don't check this path yet */
1224
1225                         /*
1226                          * provision a next check soonest,
1227                          * in case we exit abnormaly from here
1228                          */
1229                         pp->tick = conf->checkint;
1230
1231                         if (!pp->checkfn) {
1232                                 pathinfo(pp, conf->hwtable, DI_SYSFS);
1233                                 select_checkfn(pp);
1234                         }
1235
1236                         if (!pp->checkfn) {
1237                                 condlog(0, "%s: checkfn is void", pp->dev);
1238                                 continue;
1239                         }
1240                         newstate = pp->checkfn(pp->fd, checker_msg,
1241                                                &pp->checker_context);
1242
1243                         if (newstate != pp->state) {
1244                                 pp->state = newstate;
1245                                 LOG_MSG(1, checker_msg);
1246
1247                                 /*
1248                                  * upon state change, reset the checkint
1249                                  * to the shortest delay
1250                                  */
1251                                 pp->checkint = conf->checkint;
1252
1253                                 if (newstate == PATH_DOWN ||
1254                                     newstate == PATH_SHAKY) {
1255                                         /*
1256                                          * proactively fail path in the DM
1257                                          */
1258                                         fail_path(pp);
1259
1260                                         /*
1261                                          * cancel scheduled failback
1262                                          */
1263                                         pp->mpp->failback_tick = 0;
1264
1265                                         continue;
1266                                 }
1267
1268                                 /*
1269                                  * reinstate this path
1270                                  */
1271                                 reinstate_path(pp);
1272
1273                                 /*
1274                                  * need to switch group ?
1275                                  */
1276                                 update_multipath_strings(pp->mpp,
1277                                                          vecs->pathvec);
1278
1279                                 /*
1280                                  * schedule defered failback
1281                                  */
1282                                 if (pp->mpp->pgfailback > 0)
1283                                         pp->mpp->failback_tick =
1284                                                 pp->mpp->pgfailback + 1;
1285                                 else if (pp->mpp->pgfailback == -FAILBACK_IMMEDIATE &&
1286                                     need_switch_pathgroup(pp->mpp, 1))
1287                                         switch_pathgroup(pp->mpp);
1288
1289                                 /*
1290                                  * if at least one path is up in a group, and
1291                                  * the group is disabled, re-enable it
1292                                  */
1293                                 if (newstate == PATH_UP)
1294                                         enable_group(pp);
1295                         }
1296                         else if (newstate == PATH_UP || newstate == PATH_GHOST) {
1297                                 LOG_MSG(4, checker_msg);
1298                                 /*
1299                                  * double the next check delay.
1300                                  * max at conf->max_checkint
1301                                  */
1302                                 if (pp->checkint < (conf->max_checkint / 2))
1303                                         pp->checkint = 2 * pp->checkint;
1304                                 else
1305                                         pp->checkint = conf->max_checkint;
1306
1307                                 pp->tick = pp->checkint;
1308                                 condlog(4, "%s: delay next check %is",
1309                                                 pp->dev_t, pp->tick);
1310
1311                         }
1312                         pp->state = newstate;
1313
1314                         /*
1315                          * path prio refreshing
1316                          */
1317                         condlog(4, "path prio refresh");
1318                         pathinfo(pp, conf->hwtable, DI_PRIO);
1319
1320                         if (need_switch_pathgroup(pp->mpp, 0)) {
1321                                 if (pp->mpp->pgfailback > 0)
1322                                         pp->mpp->failback_tick =
1323                                                 pp->mpp->pgfailback + 1;
1324                                 else if (pp->mpp->pgfailback ==
1325                                                 -FAILBACK_IMMEDIATE)
1326                                         switch_pathgroup(pp->mpp);
1327                         }
1328                 }
1329                 defered_failback_tick(vecs->mpvec);
1330                 retry_count_tick(vecs->mpvec);
1331
1332                 if (count)
1333                         count--;
1334                 else {
1335                         condlog(4, "map garbage collection");
1336                         mpvec_garbage_collector(vecs);
1337                         count = MAPGCINT;
1338                 }
1339
1340                 lock_cleanup_pop(vecs->lock);
1341                 sleep(1);
1342         }
1343         return NULL;
1344 }
1345
1346 static struct vectors *
1347 init_paths (void)
1348 {
1349         struct vectors * vecs;
1350
1351         vecs = (struct vectors *)MALLOC(sizeof(struct vectors));
1352
1353         if (!vecs)
1354                 return NULL;
1355
1356         vecs->lock =
1357                 (pthread_mutex_t *)MALLOC(sizeof(pthread_mutex_t));
1358
1359         if (!vecs->lock)
1360                 goto out;
1361
1362         vecs->pathvec = vector_alloc();
1363
1364         if (!vecs->pathvec)
1365                 goto out1;
1366
1367         vecs->mpvec = vector_alloc();
1368
1369         if (!vecs->mpvec)
1370                 goto out2;
1371
1372         pthread_mutex_init(vecs->lock, NULL);
1373
1374         return vecs;
1375
1376 out2:
1377         vector_free(vecs->pathvec);
1378 out1:
1379         FREE(vecs->lock);
1380 out:
1381         FREE(vecs);
1382         condlog(0, "failed to init paths");
1383         return NULL;
1384 }
1385
1386 static void *
1387 signal_set(int signo, void (*func) (int))
1388 {
1389         int r;
1390         struct sigaction sig;
1391         struct sigaction osig;
1392
1393         sig.sa_handler = func;
1394         sigemptyset(&sig.sa_mask);
1395         sig.sa_flags = 0;
1396
1397         r = sigaction(signo, &sig, &osig);
1398
1399         if (r < 0)
1400                 return (SIG_ERR);
1401         else
1402                 return (osig.sa_handler);
1403 }
1404
1405 static void
1406 sighup (int sig)
1407 {
1408         condlog(3, "SIGHUP received");
1409
1410 #ifdef _DEBUG_
1411         dbg_free_final(NULL);
1412 #endif
1413 }
1414
1415 static void
1416 sigend (int sig)
1417 {
1418         exit_daemon(0);
1419 }
1420
1421 static void
1422 signal_init(void)
1423 {
1424         signal_set(SIGHUP, sighup);
1425         signal_set(SIGINT, sigend);
1426         signal_set(SIGTERM, sigend);
1427         signal_set(SIGKILL, sigend);
1428 }
1429
1430 static void
1431 setscheduler (void)
1432 {
1433         int res;
1434         static struct sched_param sched_param = {
1435                 sched_priority: 99
1436         };
1437
1438         res = sched_setscheduler (0, SCHED_RR, &sched_param);
1439
1440         if (res == -1)
1441                 condlog(LOG_WARNING, "Could not set SCHED_RR at priority 99");
1442         return;
1443 }
1444
1445 static void
1446 set_oom_adj (int val)
1447 {
1448         FILE *fp;
1449
1450         fp = fopen("/proc/self/oom_adj", "w");
1451
1452         if (!fp)
1453                 return;
1454
1455         fprintf(fp, "%i", val);
1456         fclose(fp);
1457 }
1458
1459 static int
1460 child (void * param)
1461 {
1462         pthread_t check_thr, uevent_thr, uxlsnr_thr;
1463         pthread_attr_t attr;
1464         struct vectors * vecs;
1465
1466         mlockall(MCL_CURRENT | MCL_FUTURE);
1467
1468         if (logsink)
1469                 log_thread_start();
1470
1471         condlog(2, "--------start up--------");
1472         condlog(2, "read " DEFAULT_CONFIGFILE);
1473
1474         if (load_config(DEFAULT_CONFIGFILE))
1475                 exit(1);
1476
1477         setlogmask(LOG_UPTO(conf->verbosity + 3));
1478
1479         /*
1480          * fill the voids left in the config file
1481          */
1482         if (!conf->checkint) {
1483                 conf->checkint = CHECKINT;
1484                 conf->max_checkint = MAX_CHECKINT;
1485         }
1486
1487         if (pidfile_create(DEFAULT_PIDFILE, getpid())) {
1488                 if (logsink)
1489                         log_thread_stop();
1490
1491                 exit(1);
1492         }
1493         signal_init();
1494         setscheduler();
1495         set_oom_adj(-17);
1496         vecs = init_paths();
1497
1498         if (!vecs)
1499                 exit(1);
1500
1501         if (sysfs_get_mnt_path(sysfs_path, FILE_NAME_SIZE)) {
1502                 condlog(0, "can not find sysfs mount point");
1503                 exit(1);
1504         }
1505
1506         /*
1507          * fetch paths and multipaths lists
1508          * no paths and/or no multipaths are valid scenarii
1509          * vectors maintenance will be driven by events
1510          */
1511         path_discovery(vecs->pathvec, conf, DI_SYSFS | DI_WWID | DI_CHECKER);
1512         map_discovery(vecs);
1513
1514         /*
1515          * start threads
1516          */
1517         pthread_attr_init(&attr);
1518         pthread_attr_setstacksize(&attr, 64 * 1024);
1519         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
1520
1521         pthread_create(&check_thr, &attr, checkerloop, vecs);
1522         pthread_create(&uevent_thr, &attr, ueventloop, vecs);
1523         pthread_create(&uxlsnr_thr, &attr, uxlsnrloop, vecs);
1524
1525         pthread_cond_wait(&exit_cond, &exit_mutex);
1526
1527         /*
1528          * exit path
1529          */
1530         lock(vecs->lock);
1531         remove_maps(vecs);
1532         free_pathvec(vecs->pathvec, FREE_PATHS);
1533
1534         pthread_cancel(check_thr);
1535         pthread_cancel(uevent_thr);
1536         pthread_cancel(uxlsnr_thr);
1537
1538         free_keys(keys);
1539         keys = NULL;
1540         free_handlers(handlers);
1541         handlers = NULL;
1542         free_polls();
1543
1544         unlock(vecs->lock);
1545         pthread_mutex_destroy(vecs->lock);
1546         FREE(vecs->lock);
1547         vecs->lock = NULL;
1548         FREE(vecs);
1549         vecs = NULL;
1550         free_config(conf);
1551         conf = NULL;
1552
1553         condlog(2, "--------shut down-------");
1554
1555         if (logsink)
1556                 log_thread_stop();
1557
1558 #ifdef _DEBUG_
1559         dbg_free_final(NULL);
1560 #endif
1561
1562         exit(0);
1563 }
1564
1565 int
1566 main (int argc, char *argv[])
1567 {
1568         extern char *optarg;
1569         extern int optind;
1570         int arg;
1571         int err;
1572
1573         logsink = 1;
1574
1575         if (getuid() != 0) {
1576                 fprintf(stderr, "need to be root\n");
1577                 exit(1);
1578         }
1579
1580         /* make sure we don't lock any path */
1581         chdir("/");
1582         umask(umask(077) | 022);
1583
1584         conf = alloc_config();
1585
1586         if (!conf)
1587                 exit(1);
1588
1589         while ((arg = getopt(argc, argv, ":dv:k::")) != EOF ) {
1590         switch(arg) {
1591                 case 'd':
1592                         logsink = 0;
1593                         //debug=1; /* ### comment me out ### */
1594                         break;
1595                 case 'v':
1596                         if (sizeof(optarg) > sizeof(char *) ||
1597                             !isdigit(optarg[0]))
1598                                 exit(1);
1599
1600                         conf->verbosity = atoi(optarg);
1601                         break;
1602                 case 'k':
1603                         uxclnt(optarg);
1604                         exit(0);
1605                 default:
1606                         ;
1607                 }
1608         }
1609
1610         if (!logsink)
1611                 err = 0;
1612         else
1613                 err = fork();
1614
1615         if (err < 0)
1616                 /* error */
1617                 exit(1);
1618         else if (err > 0)
1619                 /* parent dies */
1620                 exit(0);
1621         else
1622                 /* child lives */
1623                 return (child(NULL));
1624 }