usr/src/lib/libsysevent/libevchannel.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  23  */
  24
  25 #include <stdio.h>
  26 #include <ctype.h>
  27 #include <fcntl.h>
  28 #include <errno.h>
  29 #include <door.h>
  30 #include <unistd.h>
  31 #include <stddef.h>
  32 #include <stdlib.h>
  33 #include <strings.h>
  34 #include <pthread.h>
  35 #include <atomic.h>
  36 #include <signal.h>
  37 #include <sys/types.h>
  38 #include <sys/varargs.h>
  39 #include <sys/sysevent.h>
  40 #include <sys/sysevent_impl.h>
  41
  42 #include "libsysevent.h"
  43 #include "libsysevent_impl.h"
  44
  45 /*
  46  * The functions below deal with the General Purpose Event Handling framework
  47  *
  48  * sysevent_evc_bind        - create/bind application to named channel
  49  * sysevent_evc_unbind      - unbind from previously bound/created channel
  50  * sysevent_evc_subscribe   - subscribe to existing event channel
  51  * sysevent_evc_unsubscribe - unsubscribe from existing event channel
  52  * sysevent_evc_publish     - generate a system event via an event channel
  53  * sysevent_evc_control     - various channel based control operation
  54  */
  55
  56 static void kill_door_servers(evchan_subscr_t *);
  57
  58 #define misaligned(p)   ((uintptr_t)(p) & 3)    /* 4-byte alignment required */
  59
  60 static pthread_key_t nrkey = PTHREAD_ONCE_KEY_NP;
  61
  62 /*
  63  * If the current thread is a door server thread servicing a door created
  64  * for us in sysevent_evc_xsubscribe, then an attempt to unsubscribe from
  65  * within door invocation context on the same channel will deadlock in the
  66  * kernel waiting for our own invocation to complete.  Such calls are
  67  * forbidden, and we abort if they are encountered (better than hanging
  68  * unkillably).
  69  *
  70  * We'd like to offer this detection to subscriptions established with
  71  * sysevent_evc_subscribe, but we don't have control over the door service
  72  * threads in that case.  Perhaps the fix is to always use door_xcreate
  73  * even for sysevent_evc_subscribe?
  74  */
  75 static boolean_t
  76 will_deadlock(evchan_t *scp)
  77 {
  78         evchan_subscr_t *subp = pthread_getspecific(nrkey);
  79         evchan_impl_hdl_t *hdl = EVCHAN_IMPL_HNDL(scp);
  80
  81         return (subp != NULL && subp->ev_subhead == hdl ? B_TRUE : B_FALSE);
  82 }
  83
  84 /*
  85  * Check syntax of a channel name
  86  */
  87 static int
  88 sysevent_is_chan_name(const char *str)
  89 {
  90         for (; *str != '\0'; str++) {
  91                 if (!EVCH_ISCHANCHAR(*str))
  92                         return (0);
  93         }
  94
  95         return (1);
  96 }
  97
  98 /*
  99  * Check for printable characters
 100  */
 101 static int
 102 strisprint(const char *s)
 103 {
 104         for (; *s != '\0'; s++) {
 105                 if (*s < ' ' || *s > '~')
 106                         return (0);
 107         }
 108
 109         return (1);
 110 }
 111
 112 /*
 113  * sysevent_evc_bind - Create/bind application to named channel
 114  */
 115 int
 116 sysevent_evc_bind(const char *channel, evchan_t **scpp, uint32_t flags)
 117 {
 118         int chanlen;
 119         evchan_t *scp;
 120         sev_bind_args_t uargs;
 121         int ec;
 122
 123         if (scpp == NULL || misaligned(scpp)) {
 124                 return (errno = EINVAL);
 125         }
 126
 127         /* Provide useful value in error case */
 128         *scpp = NULL;
 129
 130         if (channel == NULL ||
 131             (chanlen = strlen(channel) + 1) > MAX_CHNAME_LEN) {
 132                 return (errno = EINVAL);
 133         }
 134
 135         /* Check channel syntax */
 136         if (!sysevent_is_chan_name(channel)) {
 137                 return (errno = EINVAL);
 138         }
 139
 140         if (flags & ~EVCH_B_FLAGS) {
 141                 return (errno = EINVAL);
 142         }
 143
 144         scp = calloc(1, sizeof (evchan_impl_hdl_t));
 145         if (scp == NULL) {
 146                 return (errno = ENOMEM);
 147         }
 148
 149         /*
 150          * Enable sysevent driver.  Fallback if the device link doesn't exist;
 151          * this situation can arise if a channel is bound early in system
 152          * startup, prior to devfsadm(1M) being invoked.
 153          */
 154         EV_FD(scp) = open(DEVSYSEVENT, O_RDWR);
 155         if (EV_FD(scp) == -1) {
 156                 if (errno != ENOENT) {
 157                         ec = errno == EACCES ? EPERM : errno;
 158                         free(scp);
 159                         return (errno = ec);
 160                 }
 161
 162                 EV_FD(scp) = open(DEVICESYSEVENT, O_RDWR);
 163                 if (EV_FD(scp) == -1) {
 164                         ec = errno == EACCES ? EPERM : errno;
 165                         free(scp);
 166                         return (errno = ec);
 167                 }
 168         }
 169
 170         /*
 171          * Force to close the fd's when process is doing exec.
 172          * The driver will then release stale binding handles.
 173          * The driver will release also the associated subscriptions
 174          * if EVCH_SUB_KEEP flag was not set.
 175          */
 176         (void) fcntl(EV_FD(scp), F_SETFD, FD_CLOEXEC);
 177
 178         uargs.chan_name.name = (uintptr_t)channel;
 179         uargs.chan_name.len = chanlen;
 180         uargs.flags = flags;
 181
 182         if (ioctl(EV_FD(scp), SEV_CHAN_OPEN, &uargs) != 0) {
 183                 ec = errno;
 184                 (void) close(EV_FD(scp));
 185                 free(scp);
 186                 return (errno = ec);
 187         }
 188
 189         /* Needed to detect a fork() */
 190         EV_PID(scp) = getpid();
 191         (void) mutex_init(EV_LOCK(scp), USYNC_THREAD, NULL);
 192
 193         *scpp = scp;
 194
 195         return (0);
 196 }
 197
 198 /*
 199  * sysevent_evc_unbind - Unbind from previously bound/created channel
 200  */
 201 int
 202 sysevent_evc_unbind(evchan_t *scp)
 203 {
 204         sev_unsubscribe_args_t uargs;
 205         evchan_subscr_t *subp;
 206         int errcp;
 207
 208         if (scp == NULL || misaligned(scp))
 209                 return (errno = EINVAL);
 210
 211         if (will_deadlock(scp))
 212                 return (errno = EDEADLK);
 213
 214         (void) mutex_lock(EV_LOCK(scp));
 215
 216         /*
 217          * Unsubscribe, if we are in the process which did the bind.
 218          */
 219         if (EV_PID(scp) == getpid()) {
 220                 uargs.sid.name = NULL;
 221                 uargs.sid.len = 0;
 222                 /*
 223                  * The unsubscribe ioctl will block until all door upcalls have
 224                  * drained.
 225                  */
 226                 if (ioctl(EV_FD(scp), SEV_UNSUBSCRIBE, (intptr_t)&uargs) != 0) {
 227                         errcp = errno;
 228                         (void) mutex_unlock(EV_LOCK(scp));
 229                         return (errno = errcp);
 230                 }
 231         }
 232
 233         while ((subp =  EV_SUB_NEXT(scp)) != NULL) {
 234                 EV_SUB_NEXT(scp) = subp->evsub_next;
 235
 236                 /* If door_xcreate was applied we can clean up */
 237                 if (subp->evsub_attr)
 238                         kill_door_servers(subp);
 239
 240                 if (door_revoke(subp->evsub_door_desc) != 0 && errno == EPERM)
 241                         (void) close(subp->evsub_door_desc);
 242
 243                 free(subp->evsub_sid);
 244                 free(subp);
 245         }
 246
 247         (void) mutex_unlock(EV_LOCK(scp));
 248
 249         /*
 250          * The close of the driver will do the unsubscribe if a) it is the last
 251          * close and b) we are in a child which inherited subscriptions.
 252          */
 253         (void) close(EV_FD(scp));
 254         (void) mutex_destroy(EV_LOCK(scp));
 255         free(scp);
 256
 257         return (0);
 258 }
 259
 260 /*
 261  * sysevent_evc_publish - Generate a system event via an event channel
 262  */
 263 int
 264 sysevent_evc_publish(evchan_t *scp, const char *class,
 265     const char *subclass, const char *vendor,
 266     const char *pub_name, nvlist_t *attr_list,
 267     uint32_t flags)
 268 {
 269         sysevent_t *ev;
 270         sev_publish_args_t uargs;
 271         int rc;
 272         int ec;
 273
 274         if (scp == NULL || misaligned(scp)) {
 275                 return (errno = EINVAL);
 276         }
 277
 278         /* No inheritance of binding handles via fork() */
 279         if (EV_PID(scp) != getpid()) {
 280                 return (errno = EINVAL);
 281         }
 282
 283         ev = sysevent_alloc_event((char *)class, (char *)subclass,
 284             (char *)vendor, (char *)pub_name, attr_list);
 285         if (ev == NULL) {
 286                 return (errno);
 287         }
 288
 289         uargs.ev.name = (uintptr_t)ev;
 290         uargs.ev.len = SE_SIZE(ev);
 291         uargs.flags = flags;
 292
 293         (void) mutex_lock(EV_LOCK(scp));
 294
 295         rc = ioctl(EV_FD(scp), SEV_PUBLISH, (intptr_t)&uargs);
 296         ec = errno;
 297
 298         (void) mutex_unlock(EV_LOCK(scp));
 299
 300         sysevent_free(ev);
 301
 302         if (rc != 0) {
 303                 return (ec);
 304         }
 305         return (0);
 306 }
 307
 308 /*
 309  * Generic callback which catches events from the kernel and calls
 310  * subscribers call back routine.
 311  *
 312  * Kernel guarantees that door_upcalls are disabled when unsubscription
 313  * was issued that's why cookie points always to a valid evchan_subscr_t *.
 314  *
 315  * Furthermore it's not necessary to lock subp because the sysevent
 316  * framework guarantees no unsubscription until door_return.
 317  */
 318 /*ARGSUSED3*/
 319 static void
 320 door_upcall(void *cookie, char *args, size_t alen,
 321     door_desc_t *ddp, uint_t ndid)
 322 {
 323         evchan_subscr_t *subp = EVCHAN_SUBSCR(cookie);
 324         int rval = 0;
 325
 326         /*
 327          * If we've been invoked simply to kill the thread then
 328          * exit now.
 329          */
 330         if (subp->evsub_state == EVCHAN_SUB_STATE_CLOSING)
 331                 pthread_exit(NULL);
 332
 333         if (args == NULL || alen <= (size_t)0) {
 334                 /* Skip callback execution */
 335                 rval = EINVAL;
 336         } else {
 337                 rval = subp->evsub_func((sysevent_t *)(void *)args,
 338                     subp->evsub_cookie);
 339         }
 340
 341         /*
 342          * Fill in return values for door_return
 343          */
 344         alen = sizeof (rval);
 345         bcopy(&rval, args, alen);
 346
 347         (void) door_return(args, alen, NULL, 0);
 348 }
 349
 350 static pthread_once_t xsub_thrattr_once = PTHREAD_ONCE_INIT;
 351 static pthread_attr_t xsub_thrattr;
 352
 353 static void
 354 xsub_thrattr_init(void)
 355 {
 356         (void) pthread_attr_init(&xsub_thrattr);
 357         (void) pthread_attr_setdetachstate(&xsub_thrattr,
 358             PTHREAD_CREATE_DETACHED);
 359         (void) pthread_attr_setscope(&xsub_thrattr, PTHREAD_SCOPE_SYSTEM);
 360 }
 361
 362 /*
 363  * Our door server create function is only called during initial
 364  * door_xcreate since we specify DOOR_NO_DEPLETION_CB.
 365  */
 366 int
 367 xsub_door_server_create(door_info_t *dip, void *(*startf)(void *),
 368     void *startfarg, void *cookie)
 369 {
 370         evchan_subscr_t *subp = EVCHAN_SUBSCR(cookie);
 371         struct sysevent_subattr_impl *xsa = subp->evsub_attr;
 372         pthread_attr_t *thrattr;
 373         sigset_t oset;
 374         int err;
 375
 376         if (subp->evsub_state == EVCHAN_SUB_STATE_CLOSING)
 377                 return (0);     /* shouldn't happen, but just in case */
 378
 379         /*
 380          * If sysevent_evc_xsubscribe was called electing to use a
 381          * different door server create function then let it take it
 382          * from here.
 383          */
 384         if (xsa->xs_thrcreate) {
 385                 return (xsa->xs_thrcreate(dip, startf, startfarg,
 386                     xsa->xs_thrcreate_cookie));
 387         }
 388
 389         if (xsa->xs_thrattr == NULL) {
 390                 (void) pthread_once(&xsub_thrattr_once, xsub_thrattr_init);
 391                 thrattr = &xsub_thrattr;
 392         } else {
 393                 thrattr = xsa->xs_thrattr;
 394         }
 395
 396         (void) pthread_sigmask(SIG_SETMASK, &xsa->xs_sigmask, &oset);
 397         err = pthread_create(NULL, thrattr, startf, startfarg);
 398         (void) pthread_sigmask(SIG_SETMASK, &oset, NULL);
 399
 400         return (err == 0 ? 1 : -1);
 401 }
 402
 403 void
 404 xsub_door_server_setup(void *cookie)
 405 {
 406         evchan_subscr_t *subp = EVCHAN_SUBSCR(cookie);
 407         struct sysevent_subattr_impl *xsa = subp->evsub_attr;
 408
 409         if (xsa->xs_thrsetup == NULL) {
 410                 (void) pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
 411                 (void) pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
 412         }
 413
 414         (void) pthread_setspecific(nrkey, (void *)subp);
 415
 416         if (xsa->xs_thrsetup)
 417                 xsa->xs_thrsetup(xsa->xs_thrsetup_cookie);
 418 }
 419
 420 /*
 421  * Cause private door server threads to exit.  We have already performed the
 422  * unsubscribe ioctl which stops new invocations and waits until all
 423  * existing invocations are complete.  So all server threads should be
 424  * blocked in door_return.  The door has not yet been revoked.  We will
 425  * invoke repeatedly after setting the evsub_state to be noticed on
 426  * wakeup; each invocation will result in the death of one server thread.
 427  *
 428  * You'd think it would be easier to kill these threads, such as through
 429  * pthread_cancel.  Unfortunately door_return is not a cancellation point,
 430  * and if you do cancel a thread blocked in door_return the EINTR check in
 431  * the door_return assembly logic causes us to loop with EINTR forever!
 432  */
 433 static void
 434 kill_door_servers(evchan_subscr_t *subp)
 435 {
 436         door_arg_t da;
 437
 438         bzero(&da, sizeof (da));
 439         subp->evsub_state = EVCHAN_SUB_STATE_CLOSING;
 440         membar_producer();
 441
 442         (void) door_call(subp->evsub_door_desc, &da);
 443 }
 444
 445 static int
 446 sysevent_evc_subscribe_cmn(evchan_t *scp, const char *sid, const char *class,
 447     int (*event_handler)(sysevent_t *ev, void *cookie),
 448     void *cookie, uint32_t flags, struct sysevent_subattr_impl *xsa)
 449 {
 450         evchan_subscr_t *subp;
 451         int upcall_door;
 452         sev_subscribe_args_t uargs;
 453         uint32_t sid_len;
 454         uint32_t class_len;
 455         int ec;
 456
 457         if (scp == NULL || misaligned(scp) || sid == NULL || class == NULL) {
 458                 return (errno = EINVAL);
 459         }
 460
 461         /* No inheritance of binding handles via fork() */
 462         if (EV_PID(scp) != getpid()) {
 463                 return (errno = EINVAL);
 464         }
 465
 466         if ((sid_len = strlen(sid) + 1) > MAX_SUBID_LEN || sid_len == 1 ||
 467             (class_len = strlen(class) + 1) > MAX_CLASS_LEN) {
 468                 return (errno = EINVAL);
 469         }
 470
 471         /* Check for printable characters */
 472         if (!strisprint(sid)) {
 473                 return (errno = EINVAL);
 474         }
 475
 476         if (event_handler == NULL) {
 477                 return (errno = EINVAL);
 478         }
 479
 480         if (pthread_key_create_once_np(&nrkey, NULL) != 0)
 481                 return (errno); /* ENOMEM or EAGAIN */
 482
 483         /* Create subscriber data */
 484         if ((subp = calloc(1, sizeof (evchan_subscr_t))) == NULL) {
 485                 return (errno);
 486         }
 487
 488         if ((subp->evsub_sid = strdup(sid)) == NULL) {
 489                 ec = errno;
 490                 free(subp);
 491                 return (ec);
 492         }
 493
 494         /*
 495          * EC_ALL string will not be copied to kernel - NULL is assumed
 496          */
 497         if (strcmp(class, EC_ALL) == 0) {
 498                 class = NULL;
 499                 class_len = 0;
 500         }
 501
 502         /*
 503          * Fill this in now for the xsub_door_server_setup dance
 504          */
 505         subp->ev_subhead = EVCHAN_IMPL_HNDL(scp);
 506         subp->evsub_state = EVCHAN_SUB_STATE_ACTIVE;
 507
 508         if (xsa == NULL) {
 509                 upcall_door = door_create(door_upcall, (void *)subp,
 510                     DOOR_REFUSE_DESC | DOOR_NO_CANCEL);
 511         } else {
 512                 subp->evsub_attr = xsa;
 513
 514                 /*
 515                  * Create a private door with exactly one thread to
 516                  * service the callbacks (the GPEC kernel implementation
 517                  * serializes deliveries for each subscriber id).
 518                  */
 519                 upcall_door = door_xcreate(door_upcall, (void *)subp,
 520                     DOOR_REFUSE_DESC | DOOR_NO_CANCEL | DOOR_NO_DEPLETION_CB,
 521                     xsub_door_server_create, xsub_door_server_setup,
 522                     (void *)subp, 1);
 523         }
 524
 525         if (upcall_door == -1) {
 526                 ec = errno;
 527                 free(subp->evsub_sid);
 528                 free(subp);
 529                 return (ec);
 530         }
 531
 532         /* Complete subscriber information */
 533         subp->evsub_door_desc = upcall_door;
 534         subp->evsub_func = event_handler;
 535         subp->evsub_cookie = cookie;
 536
 537         (void) mutex_lock(EV_LOCK(scp));
 538
 539         uargs.sid.name = (uintptr_t)sid;
 540         uargs.sid.len = sid_len;
 541         uargs.class_info.name = (uintptr_t)class;
 542         uargs.class_info.len = class_len;
 543         uargs.door_desc = subp->evsub_door_desc;
 544         uargs.flags = flags;
 545         if (ioctl(EV_FD(scp), SEV_SUBSCRIBE, (intptr_t)&uargs) != 0) {
 546                 ec = errno;
 547                 (void) mutex_unlock(EV_LOCK(scp));
 548                 if (xsa)
 549                         kill_door_servers(subp);
 550                 (void) door_revoke(upcall_door);
 551                 free(subp->evsub_sid);
 552                 free(subp);
 553                 return (ec);
 554         }
 555
 556         /* Attach to subscriber list */
 557         subp->evsub_next = EV_SUB_NEXT(scp);
 558         EV_SUB_NEXT(scp) = subp;
 559
 560         (void) mutex_unlock(EV_LOCK(scp));
 561
 562         return (0);
 563 }
 564
 565 /*
 566  * sysevent_evc_subscribe - subscribe to an existing event channel
 567  * using a non-private door (which will create as many server threads
 568  * as the apparent maximum concurrency requirements suggest).
 569  */
 570 int
 571 sysevent_evc_subscribe(evchan_t *scp, const char *sid, const char *class,
 572     int (*event_handler)(sysevent_t *ev, void *cookie),
 573     void *cookie, uint32_t flags)
 574 {
 575         return (sysevent_evc_subscribe_cmn(scp, sid, class, event_handler,
 576             cookie, flags, NULL));
 577 }
 578
 579 static void
 580 subattr_dfltinit(struct sysevent_subattr_impl *xsa)
 581 {
 582         (void) sigfillset(&xsa->xs_sigmask);
 583         (void) sigdelset(&xsa->xs_sigmask, SIGABRT);
 584 }
 585
 586 static struct sysevent_subattr_impl dfltsa;
 587 pthread_once_t dfltsa_inited = PTHREAD_ONCE_INIT;
 588
 589 static void
 590 init_dfltsa(void)
 591 {
 592         subattr_dfltinit(&dfltsa);
 593 }
 594
 595 /*
 596  * sysevent_evc_subscribe - subscribe to an existing event channel
 597  * using a private door with control over thread creation.
 598  */
 599 int
 600 sysevent_evc_xsubscribe(evchan_t *scp, const char *sid, const char *class,
 601     int (*event_handler)(sysevent_t *ev, void *cookie),
 602     void *cookie, uint32_t flags, sysevent_subattr_t *attr)
 603 {
 604         struct sysevent_subattr_impl *xsa;
 605
 606         if (attr != NULL) {
 607                 xsa = (struct sysevent_subattr_impl *)attr;
 608         } else {
 609                 xsa = &dfltsa;
 610                 (void) pthread_once(&dfltsa_inited, init_dfltsa);
 611         }
 612
 613         return (sysevent_evc_subscribe_cmn(scp, sid, class, event_handler,
 614             cookie, flags, xsa));
 615 }
 616
 617 sysevent_subattr_t *
 618 sysevent_subattr_alloc(void)
 619 {
 620         struct sysevent_subattr_impl *xsa = calloc(1, sizeof (*xsa));
 621
 622         if (xsa != NULL)
 623                 subattr_dfltinit(xsa);
 624
 625         return (xsa != NULL ? (sysevent_subattr_t *)xsa : NULL);
 626 }
 627
 628 void
 629 sysevent_subattr_free(sysevent_subattr_t *attr)
 630 {
 631         struct sysevent_subattr_impl *xsa =
 632             (struct sysevent_subattr_impl *)attr;
 633
 634         free(xsa);
 635 }
 636
 637 void
 638 sysevent_subattr_thrcreate(sysevent_subattr_t *attr,
 639     door_xcreate_server_func_t *thrcreate, void *cookie)
 640 {
 641         struct sysevent_subattr_impl *xsa =
 642             (struct sysevent_subattr_impl *)attr;
 643
 644         xsa->xs_thrcreate = thrcreate;
 645         xsa->xs_thrcreate_cookie = cookie;
 646 }
 647
 648 void
 649 sysevent_subattr_thrsetup(sysevent_subattr_t *attr,
 650     door_xcreate_thrsetup_func_t *thrsetup, void *cookie)
 651 {
 652         struct sysevent_subattr_impl *xsa =
 653             (struct sysevent_subattr_impl *)attr;
 654
 655         xsa->xs_thrsetup = thrsetup;
 656         xsa->xs_thrsetup_cookie = cookie;
 657 }
 658
 659 void
 660 sysevent_subattr_sigmask(sysevent_subattr_t *attr, sigset_t *set)
 661 {
 662         struct sysevent_subattr_impl *xsa =
 663             (struct sysevent_subattr_impl *)attr;
 664
 665         if (set) {
 666                 xsa->xs_sigmask = *set;
 667         } else {
 668                 (void) sigfillset(&xsa->xs_sigmask);
 669                 (void) sigdelset(&xsa->xs_sigmask, SIGABRT);
 670         }
 671 }
 672
 673 void
 674 sysevent_subattr_thrattr(sysevent_subattr_t *attr, pthread_attr_t *thrattr)
 675 {
 676         struct sysevent_subattr_impl *xsa =
 677             (struct sysevent_subattr_impl *)attr;
 678
 679         xsa->xs_thrattr = thrattr;
 680 }
 681
 682 /*
 683  * sysevent_evc_unsubscribe - Unsubscribe from an existing event channel
 684  */
 685 int
 686 sysevent_evc_unsubscribe(evchan_t *scp, const char *sid)
 687 {
 688         int all_subscribers = 0;
 689         sev_unsubscribe_args_t uargs;
 690         evchan_subscr_t *subp, *prevsubp, *tofree;
 691         int errcp;
 692         int rc;
 693
 694         if (scp == NULL || misaligned(scp))
 695                 return (errno = EINVAL);
 696
 697         if (sid == NULL || strlen(sid) == 0 ||
 698             (strlen(sid) >= MAX_SUBID_LEN))
 699                 return (errno = EINVAL);
 700
 701         /* No inheritance of binding handles via fork() */
 702         if (EV_PID(scp) != getpid())
 703                 return (errno = EINVAL);
 704
 705         if (strcmp(sid, EVCH_ALLSUB) == 0) {
 706                 all_subscribers++;
 707                 /* Indicates all subscriber id's for this channel */
 708                 uargs.sid.name = NULL;
 709                 uargs.sid.len = 0;
 710         } else {
 711                 uargs.sid.name = (uintptr_t)sid;
 712                 uargs.sid.len = strlen(sid) + 1;
 713         }
 714
 715         if (will_deadlock(scp))
 716                 return (errno = EDEADLK);
 717
 718         (void) mutex_lock(EV_LOCK(scp));
 719
 720         /*
 721          * The unsubscribe ioctl will block until all door upcalls have drained.
 722          */
 723         rc = ioctl(EV_FD(scp), SEV_UNSUBSCRIBE, (intptr_t)&uargs);
 724
 725         if (rc != 0) {
 726                 errcp = errno;
 727                 (void) mutex_unlock(EV_LOCK(scp));
 728                 return (errno = errcp); /* EFAULT, ENXIO, EINVAL possible */
 729         }
 730
 731
 732         /*
 733          * Search for the matching subscriber.  If EVCH_ALLSUB was specified
 734          * then the ioctl above will have returned 0 even if there are
 735          * no subscriptions, so the initial EV_SUB_NEXT can be NULL.
 736          */
 737         prevsubp = NULL;
 738         subp =  EV_SUB_NEXT(scp);
 739         while (subp != NULL) {
 740                 if (all_subscribers || strcmp(subp->evsub_sid, sid) == 0) {
 741                         if (prevsubp == NULL) {
 742                                 EV_SUB_NEXT(scp) = subp->evsub_next;
 743                         } else {
 744                                 prevsubp->evsub_next = subp->evsub_next;
 745                         }
 746
 747                         tofree = subp;
 748                         subp = subp->evsub_next;
 749
 750                         /* If door_xcreate was applied we can clean up */
 751                         if (tofree->evsub_attr)
 752                                 kill_door_servers(tofree);
 753
 754                         (void) door_revoke(tofree->evsub_door_desc);
 755                         free(tofree->evsub_sid);
 756                         free(tofree);
 757
 758                         /* Freed single subscriber already? */
 759                         if (all_subscribers == 0)
 760                                 break;
 761                 } else {
 762                         prevsubp = subp;
 763                         subp = subp->evsub_next;
 764                 }
 765         }
 766
 767         (void) mutex_unlock(EV_LOCK(scp));
 768
 769         return (0);
 770 }
 771
 772 /*
 773  * sysevent_evc_control - Various channel based control operation
 774  */
 775 int
 776 sysevent_evc_control(evchan_t *scp, int cmd, /* arg */ ...)
 777 {
 778         va_list ap;
 779         uint32_t *chlenp;
 780         sev_control_args_t uargs;
 781         int rc = 0;
 782
 783         if (scp == NULL || misaligned(scp)) {
 784                 return (errno = EINVAL);
 785         }
 786
 787         /* No inheritance of binding handles via fork() */
 788         if (EV_PID(scp) != getpid()) {
 789                 return (errno = EINVAL);
 790         }
 791
 792         va_start(ap, cmd);
 793
 794         uargs.cmd = cmd;
 795
 796         (void) mutex_lock(EV_LOCK(scp));
 797
 798         switch (cmd) {
 799         case EVCH_GET_CHAN_LEN:
 800         case EVCH_GET_CHAN_LEN_MAX:
 801                 chlenp = va_arg(ap, uint32_t *);
 802                 if (chlenp == NULL || misaligned(chlenp)) {
 803                         rc = EINVAL;
 804                         break;
 805                 }
 806                 rc = ioctl(EV_FD(scp), SEV_CHAN_CONTROL, (intptr_t)&uargs);
 807                 *chlenp = uargs.value;
 808                 break;
 809
 810         case EVCH_SET_CHAN_LEN:
 811                 /* Range change will be handled in framework */
 812                 uargs.value = va_arg(ap, uint32_t);
 813                 rc = ioctl(EV_FD(scp), SEV_CHAN_CONTROL, (intptr_t)&uargs);
 814                 break;
 815
 816         default:
 817                 rc = EINVAL;
 818         }
 819
 820         (void) mutex_unlock(EV_LOCK(scp));
 821
 822         if (rc == -1) {
 823                 rc = errno;
 824         }
 825
 826         va_end(ap);
 827
 828         return (errno = rc);
 829 }
 830
 831 int
 832 sysevent_evc_setpropnvl(evchan_t *scp, nvlist_t *nvl)
 833 {
 834         sev_propnvl_args_t uargs;
 835         char *buf = NULL;
 836         size_t nvlsz = 0;
 837         int rc;
 838
 839         if (scp == NULL || misaligned(scp))
 840                 return (errno = EINVAL);
 841
 842         if (nvl != NULL &&
 843             nvlist_pack(nvl, &buf, &nvlsz, NV_ENCODE_NATIVE, 0) != 0)
 844                 return (errno);
 845
 846         uargs.packednvl.name = (uint64_t)(uintptr_t)buf;
 847         uargs.packednvl.len = (uint32_t)nvlsz;
 848
 849         rc = ioctl(EV_FD(scp), SEV_SETPROPNVL, (intptr_t)&uargs);
 850
 851         if (buf)
 852                 free(buf);
 853
 854         return (rc);
 855 }
 856
 857 int
 858 sysevent_evc_getpropnvl(evchan_t *scp, nvlist_t **nvlp)
 859 {
 860         sev_propnvl_args_t uargs;
 861         char buf[1024], *bufp = buf;    /* stack buffer */
 862         size_t sz = sizeof (buf);
 863         char *buf2 = NULL;              /* allocated if stack buf too small */
 864         int64_t expgen = -1;
 865         int rc;
 866
 867         if (scp == NULL || misaligned(scp) || nvlp == NULL)
 868                 return (errno = EINVAL);
 869
 870         *nvlp = NULL;
 871
 872 again:
 873         uargs.packednvl.name = (uint64_t)(uintptr_t)bufp;
 874         uargs.packednvl.len = (uint32_t)sz;
 875
 876         rc = ioctl(EV_FD(scp), SEV_GETPROPNVL, (intptr_t)&uargs);
 877
 878         if (rc == E2BIG)
 879                 return (errno = E2BIG); /* driver refuses to copyout */
 880
 881         /*
 882          * If the packed nvlist is too big for the buffer size we offered
 883          * then the ioctl returns EOVERFLOW and indicates in the 'len'
 884          * the size required for the current property nvlist generation
 885          * (itself returned in the generation member).
 886          */
 887         if (rc == EOVERFLOW &&
 888             (buf2 == NULL || uargs.generation != expgen)) {
 889                 if (buf2 != NULL)
 890                         free(buf2);
 891
 892                 if ((sz = uargs.packednvl.len) > 1024 * 1024)
 893                         return (E2BIG);
 894
 895                 bufp = buf2 = malloc(sz);
 896
 897                 if (buf2 == NULL)
 898                         return (errno = ENOMEM);
 899
 900                 expgen = uargs.generation;
 901                 goto again;
 902         }
 903
 904         /*
 905          * The chan prop nvlist can be absent, in which case the ioctl
 906          * returns success and uargs.packednvl.len of 0;  we have already
 907          * set *nvlp to NULL.  Otherwise we must unpack the nvl.
 908          */
 909         if (rc == 0 && uargs.packednvl.len != 0 &&
 910             nvlist_unpack(bufp, uargs.packednvl.len, nvlp, 0) != 0)
 911                 rc = EINVAL;
 912
 913         if (buf2 != NULL)
 914                 free(buf2);
 915
 916         return (rc ? errno = rc : 0);
 917 }