xref: /illumos-gate/usr/src/cmd/syseventd/daemons/syseventd/syseventd.c (revision f52943a93040563107b95bccb9db87d9971ef47d)
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 /*
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  *	syseventd - The system event daemon
29  *
30  *		This daemon dispatches event buffers received from the
31  *		kernel to all interested SLM clients.  SLMs in turn
32  *		deliver the buffers to their particular application
33  *		clients.
34  */
35 #include <stdio.h>
36 #include <sys/types.h>
37 #include <dirent.h>
38 #include <stdarg.h>
39 #include <stddef.h>
40 #include <stdlib.h>
41 #include <dlfcn.h>
42 #include <door.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <signal.h>
46 #include <strings.h>
47 #include <unistd.h>
48 #include <synch.h>
49 #include <syslog.h>
50 #include <thread.h>
51 #include <libsysevent.h>
52 #include <limits.h>
53 #include <locale.h>
54 #include <sys/sysevent.h>
55 #include <sys/sysevent_impl.h>
56 #include <sys/modctl.h>
57 #include <sys/stat.h>
58 #include <sys/systeminfo.h>
59 #include <sys/wait.h>
60 
61 #include "sysevent_signal.h"
62 #include "syseventd.h"
63 #include "message.h"
64 
65 extern int insert_client(void *client, int client_type, int retry_limit);
66 extern void delete_client(int id);
67 extern void initialize_client_tbl(void);
68 
69 extern struct sysevent_client *sysevent_client_tbl[];
70 extern mutex_t client_tbl_lock;
71 
72 #define	DEBUG_LEVEL_FORK	9	/* will run in background at all */
73 					/* levels less than DEBUG_LEVEL_FORK */
74 
75 int debug_level = 0;
76 char *root_dir = "";			/* Relative root for lock and door */
77 
78 /* Maximum number of outstanding events dispatched */
79 #define	SE_EVENT_DISPATCH_CNT	100
80 
81 static int upcall_door;			/* Kernel event door */
82 static int door_upcall_retval;		/* Kernel event posting return value */
83 static int fini_pending = 0;		/* fini pending flag */
84 static int deliver_buf = 0;		/* Current event buffer from kernel */
85 static int dispatch_buf = 0;		/* Current event buffer dispatched */
86 static sysevent_t **eventbuf;		/* Global array of event buffers */
87 static struct ev_completion *event_compq;	/* Event completion queue */
88 static mutex_t ev_comp_lock;		/* Event completion queue lock */
89 static mutex_t err_mutex;		/* error logging lock */
90 static mutex_t door_lock;		/* sync door return access */
91 static rwlock_t mod_unload_lock;		/* sync module unloading */
92 
93 /* declarations and definitions for avoiding multiple daemons running */
94 #define	DAEMON_LOCK_FILE "/var/run/syseventd.lock"
95 char local_lock_file[PATH_MAX + 1];
96 static int hold_daemon_lock;
97 static int daemon_lock_fd;
98 
99 /*
100  * sema_eventbuf - guards against the global buffer eventbuf
101  *	being written to before it has been dispatched to clients
102  *
103  * sema_dispatch - synchronizes between the kernel uploading thread
104  *	(producer) and the userland dispatch_message thread (consumer).
105  *
106  * sema_resource - throttles outstanding event consumption.
107  *
108  * event_comp_cv - synchronizes threads waiting for the event completion queue
109  *			to empty or become active.
110  */
111 static sema_t sema_eventbuf, sema_dispatch, sema_resource;
112 static cond_t event_comp_cv;
113 
114 /* Self-tuning concurrency level */
115 #define	MIN_CONCURRENCY_LEVEL	4
116 static int concurrency_level = MIN_CONCURRENCY_LEVEL;
117 
118 
119 /* SLM defines */
120 #define	MODULE_SUFFIX	".so"
121 #define	EVENT_FINI	"slm_fini"
122 #define	EVENT_INIT	"slm_init"
123 
124 #define	SE_TIMEOUT	60	/* Client dispatch timeout (seconds) */
125 
126 /* syslog message related */
127 static int logflag = 0;
128 static char *prog;
129 
130 /* function prototypes */
131 static void door_upcall(void *cookie, char *args, size_t alen, door_desc_t *ddp,
132 	uint_t ndid);
133 static void dispatch_message(void);
134 static int dispatch(void);
135 static void event_completion_thr(void);
136 static void usage(void);
137 
138 static void syseventd_init(void);
139 static void syseventd_fini(int sig);
140 
141 static pid_t enter_daemon_lock(void);
142 static void exit_daemon_lock(void);
143 
144 static void
145 usage() {
146 	(void) fprintf(stderr, "usage: syseventd [-d <debug_level>] "
147 	    "[-r <root_dir>]\n");
148 	(void) fprintf(stderr, "higher debug levels get progressively ");
149 	(void) fprintf(stderr, "more detailed debug information.\n");
150 	(void) fprintf(stderr, "syseventd will run in background if ");
151 	(void) fprintf(stderr, "run with a debug_level less than %d.\n",
152 	    DEBUG_LEVEL_FORK);
153 	exit(2);
154 }
155 
156 
157 /* common exit function which ensures releasing locks */
158 void
159 syseventd_exit(int status)
160 {
161 	syseventd_print(1, "exit status = %d\n", status);
162 
163 	if (hold_daemon_lock) {
164 		exit_daemon_lock();
165 	}
166 
167 	exit(status);
168 }
169 
170 
171 /*
172  * hup_handler - SIGHUP handler.  SIGHUP is used to force a reload of
173  *		 all SLMs.  During fini, events are drained from all
174  *		 client event queues.  The events that have been consumed
175  *		 by all clients are freed from the kernel event queue.
176  *
177  *		 Events that have not yet been delivered to all clients
178  *		 are not freed and will be replayed after all SLMs have
179  *		 been (re)loaded.
180  *
181  *		 After all client event queues have been drained, each
182  *		 SLM client is unloaded.  The init phase will (re)load
183  *		 each SLM and initiate event replay and delivery from
184  *		 the kernel.
185  *
186  */
187 /*ARGSUSED*/
188 static void
189 hup_handler(int sig)
190 {
191 	syseventd_err_print(SIGHUP_CAUGHT);
192 	(void) fflush(0);
193 	syseventd_fini(sig);
194 	syseventd_init();
195 	syseventd_err_print(DAEMON_RESTARTED);
196 	(void) fflush(0);
197 }
198 
199 /*
200  * Fault handler for other signals caught
201  */
202 /*ARGSUSED*/
203 static void
204 flt_handler(int sig)
205 {
206 	char signame[SIG2STR_MAX];
207 
208 	if (sig2str(sig, signame) == -1) {
209 		syseventd_err_print(UNKNOWN_SIGNAL_CAUGHT, sig);
210 	}
211 
212 	(void) se_signal_sethandler(sig, SIG_DFL, NULL);
213 
214 	switch (sig) {
215 		case SIGINT:
216 		case SIGSTOP:
217 		case SIGTERM:
218 			/* Close kernel door */
219 			(void) door_revoke(upcall_door);
220 
221 			/* Gracefully exit current event delivery threads */
222 			syseventd_fini(sig);
223 
224 			(void) fflush(0);
225 			(void) se_signal_unblockall();
226 			syseventd_exit(1);
227 			/*NOTREACHED*/
228 		case SIGCLD:
229 		case SIGPWR:
230 		case SIGWINCH:
231 		case SIGURG:
232 		case SIGCONT:
233 		case SIGWAITING:
234 		case SIGLWP:
235 		case SIGFREEZE:
236 		case SIGTHAW:
237 		case SIGCANCEL:
238 		case SIGXRES:
239 		case SIGJVM1:
240 		case SIGJVM2:
241 		case SIGINFO:
242 			/* No need to abort */
243 			break;
244 		default:
245 			syseventd_err_print(FATAL_ERROR);
246 			abort();
247 
248 	}
249 }
250 
251 /*
252  * Daemon parent process only.
253  * Child process signal to indicate successful daemon initialization.
254  * This is the normal and expected exit path of the daemon parent.
255  */
256 /*ARGSUSED*/
257 static void
258 sigusr1(int sig)
259 {
260 	syseventd_exit(0);
261 }
262 
263 static void
264 sigwait_thr()
265 {
266 	int	sig;
267 	int	err;
268 	sigset_t signal_set;
269 
270 	for (;;) {
271 		syseventd_print(3, "sigwait thread waiting for signal\n");
272 		(void) sigfillset(&signal_set);
273 		err = sigwait(&signal_set, &sig);
274 		if (err) {
275 			syseventd_exit(2);
276 		}
277 
278 		/*
279 		 * Block all signals until the signal handler completes
280 		 */
281 		if (sig == SIGHUP) {
282 			hup_handler(sig);
283 		} else {
284 			flt_handler(sig);
285 		}
286 	}
287 	/* NOTREACHED */
288 }
289 
290 static void
291 set_root_dir(char *dir)
292 {
293 	root_dir = malloc(strlen(dir) + 1);
294 	if (root_dir == NULL) {
295 		syseventd_err_print(INIT_ROOT_DIR_ERR, strerror(errno));
296 		syseventd_exit(2);
297 	}
298 	(void) strcpy(root_dir, dir);
299 }
300 
301 int
302 main(int argc, char **argv)
303 {
304 	int i, c;
305 	int fd;
306 	pid_t pid;
307 	int has_forked = 0;
308 	extern char *optarg;
309 
310 	(void) setlocale(LC_ALL, "");
311 	(void) textdomain(TEXT_DOMAIN);
312 
313 	if (getuid() != 0) {
314 		(void) fprintf(stderr, "Must be root to run syseventd\n");
315 		syseventd_exit(1);
316 	}
317 
318 	if (argc > 5) {
319 		usage();
320 	}
321 
322 	if ((prog = strrchr(argv[0], '/')) == NULL) {
323 		prog = argv[0];
324 	} else {
325 		prog++;
326 	}
327 
328 	while ((c = getopt(argc, argv, "d:r:")) != EOF) {
329 		switch (c) {
330 		case 'd':
331 			debug_level = atoi(optarg);
332 			break;
333 		case 'r':
334 			/*
335 			 * Private flag for suninstall to run
336 			 * daemon during install.
337 			 */
338 			set_root_dir(optarg);
339 			break;
340 		case '?':
341 		default:
342 			usage();
343 		}
344 	}
345 
346 	/* demonize ourselves */
347 	if (debug_level < DEBUG_LEVEL_FORK) {
348 
349 		sigset_t mask;
350 
351 		(void) sigset(SIGUSR1, sigusr1);
352 
353 		(void) sigemptyset(&mask);
354 		(void) sigaddset(&mask, SIGUSR1);
355 		(void) sigprocmask(SIG_BLOCK, &mask, NULL);
356 
357 		if ((pid = fork()) == (pid_t)-1) {
358 			(void) fprintf(stderr,
359 			    "syseventd: fork failed - %s\n", strerror(errno));
360 			syseventd_exit(1);
361 		}
362 
363 		if (pid != 0) {
364 			/*
365 			 * parent
366 			 * handshake with the daemon so that dependents
367 			 * of the syseventd service don't start up until
368 			 * the service is actually functional
369 			 */
370 			int status;
371 			(void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
372 
373 			if (waitpid(pid, &status, 0) != pid) {
374 				/*
375 				 * child process signal indicating
376 				 * successful daemon initialization
377 				 */
378 				syseventd_exit(0);
379 			}
380 			/* child exited implying unsuccessful startup */
381 			syseventd_exit(1);
382 		}
383 
384 		/* child */
385 
386 		has_forked = 1;
387 		(void) sigset(SIGUSR1, SIG_DFL);
388 		(void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
389 
390 		(void) chdir("/");
391 		(void) setsid();
392 		if (debug_level <= 1) {
393 			closefrom(0);
394 			fd = open("/dev/null", 0);
395 			(void) dup2(fd, 1);
396 			(void) dup2(fd, 2);
397 			logflag = 1;
398 		}
399 	}
400 
401 	openlog("syseventd", LOG_PID, LOG_DAEMON);
402 
403 	(void) mutex_init(&err_mutex, USYNC_THREAD, NULL);
404 
405 	syseventd_print(8,
406 	    "syseventd started, debug level = %d\n", debug_level);
407 
408 	/* only one instance of syseventd can run at a time */
409 	if ((pid = enter_daemon_lock()) != getpid()) {
410 		syseventd_print(1,
411 		    "event daemon pid %ld already running\n", pid);
412 		exit(3);
413 	}
414 
415 	/* initialize semaphores and eventbuf */
416 	(void) sema_init(&sema_eventbuf, SE_EVENT_DISPATCH_CNT,
417 	    USYNC_THREAD, NULL);
418 	(void) sema_init(&sema_dispatch, 0, USYNC_THREAD, NULL);
419 	(void) sema_init(&sema_resource, SE_EVENT_DISPATCH_CNT,
420 	    USYNC_THREAD, NULL);
421 	(void) cond_init(&event_comp_cv, USYNC_THREAD, NULL);
422 	eventbuf = (sysevent_t **)calloc(SE_EVENT_DISPATCH_CNT,
423 	    sizeof (sysevent_t *));
424 	if (eventbuf == NULL) {
425 		syseventd_print(1, "Unable to allocate event buffer array\n");
426 		exit(2);
427 	}
428 	for (i = 0; i < SE_EVENT_DISPATCH_CNT; ++i) {
429 		eventbuf[i] = malloc(LOGEVENT_BUFSIZE);
430 		if (eventbuf[i] == NULL) {
431 			syseventd_print(1, "Unable to allocate event "
432 			    "buffers\n");
433 			exit(2);
434 		}
435 	}
436 
437 	(void) mutex_init(&client_tbl_lock, USYNC_THREAD, NULL);
438 	(void) mutex_init(&ev_comp_lock, USYNC_THREAD, NULL);
439 	(void) mutex_init(&door_lock, USYNC_THREAD, NULL);
440 	(void) rwlock_init(&mod_unload_lock, USYNC_THREAD, NULL);
441 
442 	event_compq = NULL;
443 
444 	syseventd_print(8, "start the message thread running\n");
445 
446 	/*
447 	 * Block all signals to all threads include the main thread.
448 	 * The sigwait_thr thread will process any signals and initiate
449 	 * a graceful recovery if possible.
450 	 */
451 	if (se_signal_blockall() < 0) {
452 		syseventd_err_print(INIT_SIG_BLOCK_ERR);
453 		syseventd_exit(2);
454 	}
455 
456 	if (thr_create(NULL, 0, (void *(*)(void *))dispatch_message,
457 	    (void *)0, 0, NULL) < 0) {
458 		syseventd_err_print(INIT_THR_CREATE_ERR, strerror(errno));
459 		syseventd_exit(2);
460 	}
461 	if (thr_create(NULL, 0,
462 	    (void *(*)(void *))event_completion_thr, NULL,
463 	    THR_BOUND, NULL) != 0) {
464 		syseventd_err_print(INIT_THR_CREATE_ERR, strerror(errno));
465 		syseventd_exit(2);
466 	}
467 	/* Create signal catching thread */
468 	if (thr_create(NULL, 0, (void *(*)(void *))sigwait_thr,
469 	    NULL, 0, NULL) < 0) {
470 		syseventd_err_print(INIT_THR_CREATE_ERR, strerror(errno));
471 		syseventd_exit(2);
472 	}
473 
474 	setbuf(stdout, (char *)NULL);
475 
476 	/* Initialize and load SLM clients */
477 	initialize_client_tbl();
478 	syseventd_init();
479 
480 	/* signal parent to indicate successful daemon initialization */
481 	if (has_forked) {
482 		if (kill(getppid(), SIGUSR1) != 0) {
483 			syseventd_err_print(
484 			    "signal to the parent failed - %s\n",
485 			    strerror(errno));
486 			syseventd_exit(2);
487 		}
488 	}
489 
490 	syseventd_print(8, "Pausing\n");
491 
492 	for (;;) {
493 		(void) pause();
494 	}
495 	/* NOTREACHED */
496 	return (0);
497 }
498 
499 /*
500  * door_upcall - called from the kernel via kernel sysevent door
501  *		to upload event(s).
502  *
503  *		This routine should never block.  If resources are
504  *		not available to immediately accept the event buffer
505  *		EAGAIN is returned to the kernel.
506  *
507  *		Once resources are available, the kernel is notified
508  *		via a modctl interface to resume event delivery to
509  *		syseventd.
510  *
511  */
512 /*ARGSUSED*/
513 static void
514 door_upcall(void *cookie, char *args, size_t alen,
515     door_desc_t *ddp, uint_t ndid)
516 {
517 	sysevent_t *ev;
518 	int rval;
519 
520 
521 	(void) mutex_lock(&door_lock);
522 	if (args == NULL) {
523 		rval = EINVAL;
524 	} else if (sema_trywait(&sema_eventbuf)) {
525 		ev = (sysevent_t *)
526 		    &((log_event_upcall_arg_t *)(void *)args)->buf;
527 		syseventd_print(2, "door_upcall: busy event %llx "
528 		    "retry\n", sysevent_get_seq(ev));
529 		rval = door_upcall_retval = EAGAIN;
530 	} else {
531 		/*
532 		 * Copy received message to local buffer.
533 		 */
534 		size_t size;
535 		ev = (sysevent_t *)
536 		    &((log_event_upcall_arg_t *)(void *)args)->buf;
537 
538 		syseventd_print(2, "door_upcall: event %llx in eventbuf %d\n",
539 		    sysevent_get_seq(ev), deliver_buf);
540 		size = sysevent_get_size(ev) > LOGEVENT_BUFSIZE ?
541 		    LOGEVENT_BUFSIZE : sysevent_get_size(ev);
542 		(void) bcopy(ev, eventbuf[deliver_buf], size);
543 		deliver_buf = (deliver_buf + 1) % SE_EVENT_DISPATCH_CNT;
544 		rval = 0;
545 		(void) sema_post(&sema_dispatch);
546 	}
547 
548 	(void) mutex_unlock(&door_lock);
549 
550 	/*
551 	 * Filling in return values for door_return
552 	 */
553 	(void) door_return((void *)&rval, sizeof (rval), NULL, 0);
554 	(void) door_return(NULL, 0, NULL, 0);
555 }
556 
557 /*
558  * dispatch_message - dispatch message thread
559  *			This thread spins until an event buffer is delivered
560  *			delivered from the kernel.
561  *
562  *			It will wait to dispatch an event to any clients
563  *			until adequate resources are available to process
564  *			the event buffer.
565  */
566 static void
567 dispatch_message(void)
568 {
569 	int error;
570 
571 	for (;;) {
572 		syseventd_print(3, "dispatch_message: thread started\n");
573 		/*
574 		 * Spin till a message comes
575 		 */
576 		while (sema_wait(&sema_dispatch) != 0) {
577 			syseventd_print(1,
578 			    "dispatch_message: sema_wait failed\n");
579 			(void) sleep(1);
580 		}
581 
582 		syseventd_print(3, "dispatch_message: sema_dispatch\n");
583 
584 		/*
585 		 * Wait for available resources
586 		 */
587 		while (sema_wait(&sema_resource) != 0) {
588 			syseventd_print(1, "dispatch_message: sema_wait "
589 			    "failed\n");
590 			(void) sleep(1);
591 		}
592 
593 		syseventd_print(2, "dispatch_message: eventbuf %d\n",
594 		    dispatch_buf);
595 
596 		/*
597 		 * Client dispatch
598 		 */
599 		do {
600 			error = dispatch();
601 		} while (error == EAGAIN);
602 
603 		syseventd_print(2, "eventbuf %d dispatched\n", dispatch_buf);
604 		dispatch_buf = (dispatch_buf + 1) % SE_EVENT_DISPATCH_CNT;
605 
606 		/*
607 		 * kernel received a busy signal -
608 		 * kickstart the kernel delivery thread
609 		 * door_lock blocks the kernel so we hold it for the
610 		 * shortest time possible.
611 		 */
612 		(void) mutex_lock(&door_lock);
613 		if (door_upcall_retval == EAGAIN && !fini_pending) {
614 			syseventd_print(3, "dispatch_message: retrigger "
615 			    "door_upcall_retval = %d\n",
616 			    door_upcall_retval);
617 			(void) modctl(MODEVENTS, (uintptr_t)MODEVENTS_FLUSH,
618 			    NULL, NULL, NULL, 0);
619 			door_upcall_retval = 0;
620 		}
621 		(void) mutex_unlock(&door_lock);
622 	}
623 	/* NOTREACHED */
624 }
625 
626 /*
627  * drain_eventq - Called to drain all pending events from the client's
628  *		event queue.
629  */
630 static void
631 drain_eventq(struct sysevent_client *scp, int status)
632 {
633 	struct event_dispatch_pkg *d_pkg;
634 	struct event_dispatchq *eventq, *eventq_next;
635 
636 	syseventd_print(3, "Draining eventq for client %d\n",
637 	    scp->client_num);
638 
639 	eventq = scp->eventq;
640 	while (eventq) {
641 		/*
642 		 * Mark all dispatched events as completed, but indicate the
643 		 * error status
644 		 */
645 		d_pkg = eventq->d_pkg;
646 
647 		syseventd_print(4, "drain event 0X%llx for client %d\n",
648 		    sysevent_get_seq(d_pkg->ev), scp->client_num);
649 
650 		if (d_pkg->completion_state == SE_NOT_DISPATCHED) {
651 			d_pkg->completion_status = status;
652 			d_pkg->completion_state = SE_COMPLETE;
653 			(void) sema_post(d_pkg->completion_sema);
654 		}
655 
656 		eventq_next = eventq->next;
657 		free(eventq);
658 		eventq = eventq_next;
659 		scp->eventq = eventq;
660 	}
661 }
662 
663 /*
664  * client_deliver_event_thr - Client delivery thread
665  *				This thread will process any events on this
666  *				client's eventq.
667  */
668 static void
669 client_deliver_event_thr(void *arg)
670 {
671 	int flag, error, i;
672 	sysevent_t *ev;
673 	hrtime_t now;
674 	module_t *mod;
675 	struct event_dispatchq *eventq;
676 	struct sysevent_client *scp;
677 	struct event_dispatch_pkg *d_pkg;
678 
679 	scp = (struct sysevent_client *)arg;
680 	mod = (module_t *)scp->client_data;
681 
682 	(void) mutex_lock(&scp->client_lock);
683 	for (;;) {
684 		while (scp->eventq == NULL) {
685 
686 			/*
687 			 * Client has been suspended or unloaded, go no further.
688 			 */
689 			if (fini_pending) {
690 				scp->client_flags &= ~SE_CLIENT_THR_RUNNING;
691 				syseventd_print(3, "Client %d delivery thread "
692 				    "exiting flags: 0X%x\n",
693 				    scp->client_num, scp->client_flags);
694 				(void) mutex_unlock(&scp->client_lock);
695 				return;
696 			}
697 
698 			(void) cond_wait(&scp->client_cv, &scp->client_lock);
699 
700 		}
701 
702 		/*
703 		 * Process events from the head of the eventq, eventq is locked
704 		 * going into the processing.
705 		 */
706 		eventq = scp->eventq;
707 		while (eventq != NULL) {
708 			d_pkg = eventq->d_pkg;
709 			d_pkg->completion_state = SE_OUTSTANDING;
710 			scp->eventq = eventq->next;
711 			free(eventq);
712 			(void) mutex_unlock(&scp->client_lock);
713 
714 
715 			flag = error = 0;
716 			ev = d_pkg->ev;
717 
718 			syseventd_print(3, "Start delivery for client %d "
719 			    "with retry count %d\n",
720 			    scp->client_num, d_pkg->retry_count);
721 
722 			/*
723 			 * Retry limit has been reached by this client, indicate
724 			 * that no further retries are allowed
725 			 */
726 			for (i = 0; i <= scp->retry_limit; ++i) {
727 				if (i == scp->retry_limit)
728 					flag = SE_NO_RETRY;
729 
730 				/* Start the clock for the event delivery */
731 				d_pkg->start_time = gethrtime();
732 
733 				syseventd_print(9, "Deliver to module client "
734 				    "%s\n", mod->name);
735 
736 				error = mod->deliver_event(ev, flag);
737 
738 				/* Can not allow another retry */
739 				if (i == scp->retry_limit)
740 					error = 0;
741 
742 				/* Stop the clock */
743 				now = gethrtime();
744 
745 				/*
746 				 * Suspend event processing and drain the
747 				 * event q for latent clients
748 				 */
749 				if (now - d_pkg->start_time >
750 				    ((hrtime_t)SE_TIMEOUT * NANOSEC)) {
751 					syseventd_print(1, "Unresponsive "
752 					    "client %d: Draining eventq and "
753 					    "suspending event delivery\n",
754 					    scp->client_num);
755 					(void) mutex_lock(&scp->client_lock);
756 					scp->client_flags &=
757 					    ~SE_CLIENT_THR_RUNNING;
758 					scp->client_flags |=
759 					    SE_CLIENT_SUSPENDED;
760 
761 					/* Cleanup current event */
762 					d_pkg->completion_status = EFAULT;
763 					d_pkg->completion_state = SE_COMPLETE;
764 					(void) sema_post(
765 					    d_pkg->completion_sema);
766 
767 					/*
768 					 * Drain the remaining events from the
769 					 * queue.
770 					 */
771 					drain_eventq(scp, EINVAL);
772 					(void) mutex_unlock(&scp->client_lock);
773 					return;
774 				}
775 
776 				/* Event delivery retry requested */
777 				if (fini_pending || error != EAGAIN) {
778 					break;
779 				} else {
780 					(void) sleep(SE_RETRY_TIME);
781 				}
782 			}
783 
784 			(void) mutex_lock(&scp->client_lock);
785 			d_pkg->completion_status = error;
786 			d_pkg->completion_state = SE_COMPLETE;
787 			(void) sema_post(d_pkg->completion_sema);
788 			syseventd_print(3, "Completed delivery with "
789 			    "error %d\n", error);
790 			eventq = scp->eventq;
791 		}
792 
793 		syseventd_print(3, "No more events to process for client %d\n",
794 		    scp->client_num);
795 
796 		/* Return if this was a synchronous delivery */
797 		if (!SE_CLIENT_IS_THR_RUNNING(scp)) {
798 			(void) mutex_unlock(&scp->client_lock);
799 			return;
800 		}
801 
802 	}
803 }
804 
805 /*
806  * client_deliver_event - Client specific event delivery
807  *			This routine will allocate and initialize the
808  *			neccessary per-client dispatch data.
809  *
810  *			If the eventq is not empty, it may be assumed that
811  *			a delivery thread exists for this client and the
812  *			dispatch data is appended to the eventq.
813  *
814  *			The dispatch package is freed by the event completion
815  *			thread (event_completion_thr) and the eventq entry
816  *			is freed by the event delivery thread.
817  */
818 static struct event_dispatch_pkg *
819 client_deliver_event(struct sysevent_client *scp, sysevent_t *ev,
820 	sema_t *completion_sema)
821 {
822 	size_t ev_sz = sysevent_get_size(ev);
823 	struct event_dispatchq *newq, *tmp;
824 	struct event_dispatch_pkg *d_pkg;
825 
826 	syseventd_print(3, "client_deliver_event: id 0x%llx size %d\n",
827 	    (longlong_t)sysevent_get_seq(ev), ev_sz);
828 	if (debug_level == 9) {
829 		se_print(stdout, ev);
830 	}
831 
832 	/*
833 	 * Check for suspended client
834 	 */
835 	(void) mutex_lock(&scp->client_lock);
836 	if (SE_CLIENT_IS_SUSPENDED(scp) || !SE_CLIENT_IS_THR_RUNNING(scp)) {
837 		(void) mutex_unlock(&scp->client_lock);
838 		return (NULL);
839 	}
840 
841 	/*
842 	 * Allocate a new dispatch package and eventq entry
843 	 */
844 	newq = (struct event_dispatchq *)malloc(
845 	    sizeof (struct event_dispatchq));
846 	if (newq == NULL) {
847 		(void) mutex_unlock(&scp->client_lock);
848 		return (NULL);
849 	}
850 
851 	d_pkg = (struct event_dispatch_pkg *)malloc(
852 	    sizeof (struct event_dispatch_pkg));
853 	if (d_pkg == NULL) {
854 		free(newq);
855 		(void) mutex_unlock(&scp->client_lock);
856 		return (NULL);
857 	}
858 
859 	/* Initialize the dispatch package */
860 	d_pkg->scp = scp;
861 	d_pkg->retry_count = 0;
862 	d_pkg->completion_status = 0;
863 	d_pkg->completion_state = SE_NOT_DISPATCHED;
864 	d_pkg->completion_sema = completion_sema;
865 	d_pkg->ev = ev;
866 	newq->d_pkg = d_pkg;
867 	newq->next = NULL;
868 
869 	if (scp->eventq != NULL) {
870 
871 		/* Add entry to the end of the eventq */
872 		tmp = scp->eventq;
873 		while (tmp->next != NULL)
874 			tmp = tmp->next;
875 		tmp->next = newq;
876 	} else {
877 		/* event queue empty, wakeup delivery thread */
878 		scp->eventq = newq;
879 		(void) cond_signal(&scp->client_cv);
880 	}
881 	(void) mutex_unlock(&scp->client_lock);
882 
883 	return (d_pkg);
884 }
885 
886 /*
887  * event_completion_thr - Event completion thread.  This thread routine
888  *			waits for all client delivery thread to complete
889  *			delivery of a particular event.
890  */
891 static void
892 event_completion_thr()
893 {
894 	int ret, i, client_count, ok_to_free;
895 	sysevent_id_t eid;
896 	struct sysevent_client *scp;
897 	struct ev_completion *ev_comp;
898 	struct event_dispatchq *dispatchq;
899 	struct event_dispatch_pkg *d_pkg;
900 
901 	(void) mutex_lock(&ev_comp_lock);
902 	for (;;) {
903 		while (event_compq == NULL) {
904 			(void) cond_wait(&event_comp_cv, &ev_comp_lock);
905 		}
906 
907 		/*
908 		 * Process event completions from the head of the
909 		 * completion queue
910 		 */
911 		ev_comp = event_compq;
912 		while (ev_comp) {
913 			(void) mutex_unlock(&ev_comp_lock);
914 			eid.eid_seq = sysevent_get_seq(ev_comp->ev);
915 			sysevent_get_time(ev_comp->ev, &eid.eid_ts);
916 			client_count = ev_comp->client_count;
917 			ok_to_free = 1;
918 
919 			syseventd_print(3, "Wait for event completion of "
920 			    "event 0X%llx on %d clients\n",
921 			    eid.eid_seq, client_count);
922 
923 			while (client_count) {
924 				syseventd_print(9, "Waiting for %d clients on "
925 				    "event id 0X%llx\n", client_count,
926 				    eid.eid_seq);
927 
928 				(void) sema_wait(&ev_comp->client_sema);
929 				--client_count;
930 			}
931 
932 			syseventd_print(3, "Cleaning up clients for event "
933 			    "0X%llx\n", eid.eid_seq);
934 			dispatchq = ev_comp->dispatch_list;
935 			while (dispatchq != NULL) {
936 				d_pkg = dispatchq->d_pkg;
937 				scp = d_pkg->scp;
938 
939 				if (d_pkg->completion_status == EAGAIN)
940 					ok_to_free = 0;
941 
942 				syseventd_print(4, "Delivery of 0X%llx "
943 				    "complete for client %d retry count %d "
944 				    "status %d\n", eid.eid_seq,
945 				    scp->client_num,
946 				    d_pkg->retry_count,
947 				    d_pkg->completion_status);
948 
949 				free(d_pkg);
950 				ev_comp->dispatch_list = dispatchq->next;
951 				free(dispatchq);
952 				dispatchq = ev_comp->dispatch_list;
953 			}
954 
955 			if (ok_to_free) {
956 				for (i = 0; i < MAX_MODCTL_RETRY; ++i) {
957 					if ((ret = modctl(MODEVENTS,
958 					    (uintptr_t)MODEVENTS_FREEDATA,
959 					    (uintptr_t)&eid, NULL,
960 					    NULL, 0)) != 0) {
961 						syseventd_print(1, "attempting "
962 						    "to free event 0X%llx\n",
963 						    eid.eid_seq);
964 
965 						/*
966 						 * Kernel may need time to
967 						 * move this event buffer to
968 						 * the sysevent sent queue
969 						 */
970 						(void) sleep(1);
971 					} else {
972 						break;
973 					}
974 				}
975 				if (ret) {
976 					syseventd_print(1, "Unable to free "
977 					    "event 0X%llx from the "
978 					    "kernel\n", eid.eid_seq);
979 				}
980 			} else {
981 				syseventd_print(1, "Not freeing event 0X%llx\n",
982 				    eid.eid_seq);
983 			}
984 
985 			syseventd_print(2, "Event delivery complete for id "
986 			    "0X%llx\n", eid.eid_seq);
987 
988 			(void) mutex_lock(&ev_comp_lock);
989 			event_compq = ev_comp->next;
990 			free(ev_comp->ev);
991 			free(ev_comp);
992 			ev_comp = event_compq;
993 			(void) sema_post(&sema_resource);
994 		}
995 
996 		/*
997 		 * Event completion queue is empty, signal possible unload
998 		 * operation
999 		 */
1000 		(void) cond_signal(&event_comp_cv);
1001 
1002 		syseventd_print(3, "No more events\n");
1003 	}
1004 }
1005 
1006 /*
1007  * dispatch - Dispatch the current event buffer to all valid SLM clients.
1008  */
1009 static int
1010 dispatch(void)
1011 {
1012 	int ev_sz, i, client_count = 0;
1013 	sysevent_t *new_ev;
1014 	sysevent_id_t eid;
1015 	struct ev_completion *ev_comp, *tmp;
1016 	struct event_dispatchq *dispatchq, *client_list;
1017 	struct event_dispatch_pkg *d_pkg;
1018 
1019 	/* Check for module unload operation */
1020 	if (rw_tryrdlock(&mod_unload_lock) != 0) {
1021 		syseventd_print(2, "unload in progress abort delivery\n");
1022 		(void) sema_post(&sema_eventbuf);
1023 		(void) sema_post(&sema_resource);
1024 		return (0);
1025 	}
1026 
1027 	syseventd_print(3, "deliver dispatch buffer %d", dispatch_buf);
1028 	eid.eid_seq = sysevent_get_seq(eventbuf[dispatch_buf]);
1029 	sysevent_get_time(eventbuf[dispatch_buf], &eid.eid_ts);
1030 	syseventd_print(3, "deliver msg id: 0x%llx\n", eid.eid_seq);
1031 
1032 	/*
1033 	 * ev_comp is used to hold event completion data.  It is freed
1034 	 * by the event completion thread (event_completion_thr).
1035 	 */
1036 	ev_comp = (struct ev_completion *)
1037 	    malloc(sizeof (struct ev_completion));
1038 	if (ev_comp == NULL) {
1039 		(void) rw_unlock(&mod_unload_lock);
1040 		syseventd_print(1, "Can not allocate event completion buffer "
1041 		    "for event id 0X%llx\n", eid.eid_seq);
1042 		return (EAGAIN);
1043 	}
1044 	ev_comp->dispatch_list = NULL;
1045 	ev_comp->next = NULL;
1046 	(void) sema_init(&ev_comp->client_sema, 0, USYNC_THREAD, NULL);
1047 
1048 	ev_sz = sysevent_get_size(eventbuf[dispatch_buf]);
1049 	new_ev = calloc(1, ev_sz);
1050 	if (new_ev == NULL) {
1051 		free(ev_comp);
1052 		(void) rw_unlock(&mod_unload_lock);
1053 		syseventd_print(1, "Can not allocate new event buffer "
1054 		"for event id 0X%llx\n", eid.eid_seq);
1055 		return (EAGAIN);
1056 	}
1057 
1058 
1059 	/*
1060 	 * For long messages, copy additional data from kernel
1061 	 */
1062 	if (ev_sz > LOGEVENT_BUFSIZE) {
1063 		int ret = 0;
1064 
1065 		/* Ok to release eventbuf for next event buffer from kernel */
1066 		(void) sema_post(&sema_eventbuf);
1067 
1068 		for (i = 0; i < MAX_MODCTL_RETRY; ++i) {
1069 			if ((ret = modctl(MODEVENTS,
1070 			    (uintptr_t)MODEVENTS_GETDATA,
1071 			    (uintptr_t)&eid,
1072 			    (uintptr_t)ev_sz,
1073 			    (uintptr_t)new_ev, 0))
1074 			    == 0)
1075 				break;
1076 			else
1077 				(void) sleep(1);
1078 		}
1079 		if (ret) {
1080 			syseventd_print(1, "GET_DATA failed for 0X%llx:%llx\n",
1081 			    eid.eid_ts, eid.eid_seq);
1082 			free(new_ev);
1083 			free(ev_comp);
1084 			(void) rw_unlock(&mod_unload_lock);
1085 			return (EAGAIN);
1086 		}
1087 	} else {
1088 		(void) bcopy(eventbuf[dispatch_buf], new_ev, ev_sz);
1089 		/* Ok to release eventbuf for next event buffer from kernel */
1090 		(void) sema_post(&sema_eventbuf);
1091 	}
1092 
1093 
1094 	/*
1095 	 * Deliver a copy of eventbuf to clients so
1096 	 * eventbuf can be used for the next message
1097 	 */
1098 	for (i = 0; i < MAX_SLM; ++i) {
1099 
1100 		/* Don't bother for suspended or unloaded clients */
1101 		if (!SE_CLIENT_IS_LOADED(sysevent_client_tbl[i]) ||
1102 		    SE_CLIENT_IS_SUSPENDED(sysevent_client_tbl[i]))
1103 			continue;
1104 
1105 		/*
1106 		 * Allocate event dispatch queue entry.  All queue entries
1107 		 * are freed by the event completion thread as client
1108 		 * delivery completes.
1109 		 */
1110 		dispatchq = (struct event_dispatchq *)malloc(
1111 		    sizeof (struct event_dispatchq));
1112 		if (dispatchq == NULL) {
1113 			syseventd_print(1, "Can not allocate dispatch q "
1114 			"for event id 0X%llx client %d\n", eid.eid_seq, i);
1115 			continue;
1116 		}
1117 		dispatchq->next = NULL;
1118 
1119 		/* Initiate client delivery */
1120 		d_pkg = client_deliver_event(sysevent_client_tbl[i],
1121 		    new_ev, &ev_comp->client_sema);
1122 		if (d_pkg == NULL) {
1123 			syseventd_print(1, "Can not allocate dispatch "
1124 			    "package for event id 0X%llx client %d\n",
1125 			    eid.eid_seq, i);
1126 			free(dispatchq);
1127 			continue;
1128 		}
1129 		dispatchq->d_pkg = d_pkg;
1130 		++client_count;
1131 
1132 		if (ev_comp->dispatch_list == NULL) {
1133 			ev_comp->dispatch_list = dispatchq;
1134 			client_list = dispatchq;
1135 		} else {
1136 			client_list->next = dispatchq;
1137 			client_list = client_list->next;
1138 		}
1139 	}
1140 
1141 	ev_comp->client_count = client_count;
1142 	ev_comp->ev = new_ev;
1143 
1144 	(void) mutex_lock(&ev_comp_lock);
1145 
1146 	if (event_compq == NULL) {
1147 		syseventd_print(3, "Wakeup event completion thread for "
1148 		    "id 0X%llx\n", eid.eid_seq);
1149 		event_compq = ev_comp;
1150 		(void) cond_signal(&event_comp_cv);
1151 	} else {
1152 
1153 		/* Add entry to the end of the event completion queue */
1154 		tmp = event_compq;
1155 		while (tmp->next != NULL)
1156 			tmp = tmp->next;
1157 		tmp->next = ev_comp;
1158 		syseventd_print(3, "event added to completion queue for "
1159 		    "id 0X%llx\n", eid.eid_seq);
1160 	}
1161 	(void) mutex_unlock(&ev_comp_lock);
1162 	(void) rw_unlock(&mod_unload_lock);
1163 
1164 	return (0);
1165 }
1166 
1167 #define	MODULE_DIR_HW	"/usr/platform/%s/lib/sysevent/modules/"
1168 #define	MODULE_DIR_GEN	"/usr/lib/sysevent/modules/"
1169 #define	MOD_DIR_NUM	3
1170 static char dirname[MOD_DIR_NUM][MAXPATHLEN];
1171 
1172 static char *
1173 dir_num2name(int dirnum)
1174 {
1175 	char infobuf[MAXPATHLEN];
1176 
1177 	if (dirnum >= MOD_DIR_NUM)
1178 		return (NULL);
1179 
1180 	if (dirname[0][0] == '\0') {
1181 		if (sysinfo(SI_PLATFORM, infobuf, MAXPATHLEN) == -1) {
1182 			syseventd_print(1, "dir_num2name: "
1183 			    "sysinfo error %s\n", strerror(errno));
1184 			return (NULL);
1185 		} else if (snprintf(dirname[0], sizeof (dirname[0]),
1186 		    MODULE_DIR_HW, infobuf) >= sizeof (dirname[0])) {
1187 			syseventd_print(1, "dir_num2name: "
1188 			    "platform name too long: %s\n",
1189 			    infobuf);
1190 			return (NULL);
1191 		}
1192 		if (sysinfo(SI_MACHINE, infobuf, MAXPATHLEN) == -1) {
1193 			syseventd_print(1, "dir_num2name: "
1194 			    "sysinfo error %s\n", strerror(errno));
1195 			return (NULL);
1196 		} else if (snprintf(dirname[1], sizeof (dirname[1]),
1197 		    MODULE_DIR_HW, infobuf) >= sizeof (dirname[1])) {
1198 			syseventd_print(1, "dir_num2name: "
1199 			    "machine name too long: %s\n",
1200 			    infobuf);
1201 			return (NULL);
1202 		}
1203 		(void) strcpy(dirname[2], MODULE_DIR_GEN);
1204 	}
1205 
1206 	return (dirname[dirnum]);
1207 }
1208 
1209 
1210 /*
1211  * load_modules - Load modules found in the common syseventd module directories
1212  *		Modules that do not provide valid interfaces are rejected.
1213  */
1214 static void
1215 load_modules(char *dirname)
1216 {
1217 	int client_id;
1218 	DIR *mod_dir;
1219 	module_t *mod;
1220 	struct dirent *entp;
1221 	struct slm_mod_ops *mod_ops;
1222 	struct sysevent_client *scp;
1223 
1224 	if (dirname == NULL)
1225 		return;
1226 
1227 	/* Return silently if module directory does not exist */
1228 	if ((mod_dir = opendir(dirname)) == NULL) {
1229 		syseventd_print(1, "Unable to open module directory %s: %s\n",
1230 		    dirname, strerror(errno));
1231 		return;
1232 	}
1233 
1234 	syseventd_print(3, "loading modules from %s\n", dirname);
1235 
1236 	/*
1237 	 * Go through directory, looking for files ending with .so
1238 	 */
1239 	while ((entp = readdir(mod_dir)) != NULL) {
1240 		void *dlh, *f;
1241 		char *tmp, modpath[MAXPATHLEN];
1242 
1243 		if (((tmp = strstr(entp->d_name, MODULE_SUFFIX)) == NULL) ||
1244 		    (tmp[strlen(MODULE_SUFFIX)] != '\0')) {
1245 			continue;
1246 		}
1247 
1248 		if (snprintf(modpath, sizeof (modpath), "%s%s",
1249 		    dirname, entp->d_name) >= sizeof (modpath)) {
1250 			syseventd_err_print(INIT_PATH_ERR, modpath);
1251 			continue;
1252 		}
1253 		if ((dlh = dlopen(modpath, RTLD_LAZY)) == NULL) {
1254 			syseventd_err_print(LOAD_MOD_DLOPEN_ERR,
1255 			    modpath, dlerror());
1256 			continue;
1257 		} else if ((f = dlsym(dlh, EVENT_INIT)) == NULL) {
1258 			syseventd_err_print(LOAD_MOD_NO_INIT,
1259 			    modpath, dlerror());
1260 			(void) dlclose(dlh);
1261 			continue;
1262 		}
1263 
1264 		mod = malloc(sizeof (*mod));
1265 		if (mod == NULL) {
1266 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "mod",
1267 			    strerror(errno));
1268 			(void) dlclose(dlh);
1269 			continue;
1270 		}
1271 
1272 		mod->name = strdup(entp->d_name);
1273 		if (mod->name == NULL) {
1274 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "mod->name",
1275 			    strerror(errno));
1276 			(void) dlclose(dlh);
1277 			free(mod);
1278 			continue;
1279 		}
1280 
1281 		mod->dlhandle = dlh;
1282 		mod->event_mod_init = (struct slm_mod_ops *(*)())f;
1283 
1284 		/* load in other module functions */
1285 		mod->event_mod_fini = (void (*)())dlsym(dlh, EVENT_FINI);
1286 		if (mod->event_mod_fini == NULL) {
1287 			syseventd_err_print(LOAD_MOD_DLSYM_ERR, mod->name,
1288 			    dlerror());
1289 			free(mod->name);
1290 			free(mod);
1291 			(void) dlclose(dlh);
1292 			continue;
1293 		}
1294 
1295 		/* Call module init routine */
1296 		if ((mod_ops = mod->event_mod_init()) == NULL) {
1297 			syseventd_err_print(LOAD_MOD_EINVAL, mod->name);
1298 			free(mod->name);
1299 			free(mod);
1300 			(void) dlclose(dlh);
1301 			continue;
1302 		}
1303 		if (mod_ops->major_version != SE_MAJOR_VERSION) {
1304 			syseventd_err_print(LOAD_MOD_VERSION_MISMATCH,
1305 			    mod->name, SE_MAJOR_VERSION,
1306 			    mod_ops->major_version);
1307 			mod->event_mod_fini();
1308 			free(mod->name);
1309 			free(mod);
1310 			(void) dlclose(dlh);
1311 			continue;
1312 		}
1313 
1314 		mod->deliver_event = mod_ops->deliver_event;
1315 		/* Add module entry to client list */
1316 		if ((client_id = insert_client((void *)mod, SLM_CLIENT,
1317 		    (mod_ops->retry_limit <= SE_MAX_RETRY_LIMIT ?
1318 		    mod_ops->retry_limit : SE_MAX_RETRY_LIMIT))) < 0) {
1319 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "insert_client",
1320 			    strerror(errno));
1321 			mod->event_mod_fini();
1322 			free(mod->name);
1323 			free(mod);
1324 			(void) dlclose(dlh);
1325 			continue;
1326 		}
1327 
1328 		scp = sysevent_client_tbl[client_id];
1329 		++concurrency_level;
1330 		(void) thr_setconcurrency(concurrency_level);
1331 		if (thr_create(NULL, 0,
1332 		    (void *(*)(void *))client_deliver_event_thr,
1333 		    (void *)scp, THR_BOUND, &scp->tid) != 0) {
1334 
1335 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "insert_client",
1336 			    strerror(errno));
1337 			mod->event_mod_fini();
1338 			free(mod->name);
1339 			free(mod);
1340 			(void) dlclose(dlh);
1341 			continue;
1342 		}
1343 		scp->client_flags |= SE_CLIENT_THR_RUNNING;
1344 
1345 		syseventd_print(3, "loaded module %s\n", entp->d_name);
1346 	}
1347 
1348 	(void) closedir(mod_dir);
1349 	syseventd_print(3, "modules loaded\n");
1350 }
1351 
1352 /*
1353  * unload_modules - modules are unloaded prior to graceful shutdown or
1354  *			before restarting the daemon upon receipt of
1355  *			SIGHUP.
1356  */
1357 static void
1358 unload_modules(int sig)
1359 {
1360 	int			i, count, done;
1361 	module_t		*mod;
1362 	struct sysevent_client	*scp;
1363 
1364 	/*
1365 	 * unload modules that are ready, skip those that have not
1366 	 * drained their event queues.
1367 	 */
1368 	count = done = 0;
1369 	while (done < MAX_SLM) {
1370 		/* Don't wait indefinitely for unresponsive clients */
1371 		if (sig != SIGHUP && count > SE_TIMEOUT) {
1372 			break;
1373 		}
1374 
1375 		done = 0;
1376 
1377 		/* Shutdown clients */
1378 		for (i = 0; i < MAX_SLM; ++i) {
1379 			scp = sysevent_client_tbl[i];
1380 			if (mutex_trylock(&scp->client_lock) == 0) {
1381 				if (scp->client_type != SLM_CLIENT ||
1382 				    scp->client_data == NULL) {
1383 					(void) mutex_unlock(&scp->client_lock);
1384 					done++;
1385 					continue;
1386 				}
1387 			} else {
1388 				syseventd_print(3, "Skipping unload of "
1389 				    "client %d: client locked\n",
1390 				    scp->client_num);
1391 				continue;
1392 			}
1393 
1394 			/*
1395 			 * Drain the eventq and wait for delivery thread to
1396 			 * cleanly exit
1397 			 */
1398 			drain_eventq(scp, EAGAIN);
1399 			(void) cond_signal(&scp->client_cv);
1400 			(void) mutex_unlock(&scp->client_lock);
1401 			(void) thr_join(scp->tid, NULL, NULL);
1402 
1403 			/*
1404 			 * It is now safe to unload the module
1405 			 */
1406 			mod = (module_t *)scp->client_data;
1407 			syseventd_print(2, "Unload %s\n", mod->name);
1408 			mod->event_mod_fini();
1409 			(void) dlclose(mod->dlhandle);
1410 			free(mod->name);
1411 			(void) mutex_lock(&client_tbl_lock);
1412 			delete_client(i);
1413 			(void) mutex_unlock(&client_tbl_lock);
1414 			++done;
1415 
1416 		}
1417 		++count;
1418 		(void) sleep(1);
1419 	}
1420 
1421 	/*
1422 	 * Wait for event completions
1423 	 */
1424 	syseventd_print(2, "waiting for event completions\n");
1425 	(void) mutex_lock(&ev_comp_lock);
1426 	while (event_compq != NULL) {
1427 		(void) cond_wait(&event_comp_cv, &ev_comp_lock);
1428 	}
1429 	(void) mutex_unlock(&ev_comp_lock);
1430 }
1431 
1432 /*
1433  * syseventd_init - Called at daemon (re)start-up time to load modules
1434  *			and kickstart the kernel delivery engine.
1435  */
1436 static void
1437 syseventd_init()
1438 {
1439 	int i, fd;
1440 	char local_door_file[PATH_MAX + 1];
1441 
1442 	fini_pending = 0;
1443 
1444 	concurrency_level = MIN_CONCURRENCY_LEVEL;
1445 	(void) thr_setconcurrency(concurrency_level);
1446 
1447 	/*
1448 	 * Load client modules for event delivering
1449 	 */
1450 	for (i = 0; i < MOD_DIR_NUM; ++i) {
1451 		load_modules(dir_num2name(i));
1452 	}
1453 
1454 	/*
1455 	 * Create kernel delivery door service
1456 	 */
1457 	syseventd_print(8, "Create a door for kernel upcalls\n");
1458 	if (snprintf(local_door_file, sizeof (local_door_file), "%s%s",
1459 	    root_dir, LOGEVENT_DOOR_UPCALL) >= sizeof (local_door_file)) {
1460 		syseventd_err_print(INIT_PATH_ERR, local_door_file);
1461 		syseventd_exit(5);
1462 	}
1463 
1464 	/*
1465 	 * Remove door file for robustness.
1466 	 */
1467 	if (unlink(local_door_file) != 0)
1468 		syseventd_print(8, "Unlink of %s failed.\n", local_door_file);
1469 
1470 	fd = open(local_door_file, O_CREAT|O_RDWR, S_IREAD|S_IWRITE);
1471 	if ((fd == -1) && (errno != EEXIST)) {
1472 		syseventd_err_print(INIT_OPEN_DOOR_ERR, strerror(errno));
1473 		syseventd_exit(5);
1474 	}
1475 	(void) close(fd);
1476 
1477 	upcall_door = door_create(door_upcall, NULL,
1478 	    DOOR_REFUSE_DESC | DOOR_NO_CANCEL);
1479 	if (upcall_door == -1) {
1480 		syseventd_err_print(INIT_CREATE_DOOR_ERR, strerror(errno));
1481 		syseventd_exit(5);
1482 	}
1483 
1484 	(void) fdetach(local_door_file);
1485 retry:
1486 	if (fattach(upcall_door, local_door_file) != 0) {
1487 		if (errno == EBUSY)
1488 			goto retry;
1489 		syseventd_err_print(INIT_FATTACH_ERR, strerror(errno));
1490 		(void) door_revoke(upcall_door);
1491 		syseventd_exit(5);
1492 	}
1493 
1494 	/*
1495 	 * Tell kernel the door name and start delivery
1496 	 */
1497 	syseventd_print(2,
1498 	    "local_door_file = %s\n", local_door_file);
1499 	if (modctl(MODEVENTS,
1500 	    (uintptr_t)MODEVENTS_SET_DOOR_UPCALL_FILENAME,
1501 	    (uintptr_t)local_door_file, NULL, NULL, 0) < 0) {
1502 		syseventd_err_print(INIT_DOOR_NAME_ERR, strerror(errno));
1503 		syseventd_exit(6);
1504 	}
1505 
1506 	door_upcall_retval = 0;
1507 
1508 	if (modctl(MODEVENTS, (uintptr_t)MODEVENTS_FLUSH, NULL, NULL, NULL, 0)
1509 	    < 0) {
1510 		syseventd_err_print(KERNEL_REPLAY_ERR, strerror(errno));
1511 		syseventd_exit(7);
1512 	}
1513 }
1514 
1515 /*
1516  * syseventd_fini - shut down daemon, but do not exit
1517  */
1518 static void
1519 syseventd_fini(int sig)
1520 {
1521 	/*
1522 	 * Indicate that event queues should be drained and no
1523 	 * additional events be accepted
1524 	 */
1525 	fini_pending = 1;
1526 
1527 	/* Close the kernel event door to halt delivery */
1528 	(void) door_revoke(upcall_door);
1529 
1530 	syseventd_print(1, "Unloading modules\n");
1531 	(void) rw_wrlock(&mod_unload_lock);
1532 	unload_modules(sig);
1533 	(void) rw_unlock(&mod_unload_lock);
1534 
1535 }
1536 
1537 /*
1538  * enter_daemon_lock - lock the daemon file lock
1539  *
1540  * Use an advisory lock to ensure that only one daemon process is active
1541  * in the system at any point in time.	If the lock is held by another
1542  * process, do not block but return the pid owner of the lock to the
1543  * caller immediately.	The lock is cleared if the holding daemon process
1544  * exits for any reason even if the lock file remains, so the daemon can
1545  * be restarted if necessary.  The lock file is DAEMON_LOCK_FILE.
1546  */
1547 static pid_t
1548 enter_daemon_lock(void)
1549 {
1550 	struct flock	lock;
1551 
1552 	syseventd_print(8, "enter_daemon_lock: lock file = %s\n",
1553 	    DAEMON_LOCK_FILE);
1554 
1555 	if (snprintf(local_lock_file, sizeof (local_lock_file), "%s%s",
1556 	    root_dir, DAEMON_LOCK_FILE) >= sizeof (local_lock_file)) {
1557 		syseventd_err_print(INIT_PATH_ERR, local_lock_file);
1558 		syseventd_exit(8);
1559 	}
1560 	daemon_lock_fd = open(local_lock_file, O_CREAT|O_RDWR, 0644);
1561 	if (daemon_lock_fd < 0) {
1562 		syseventd_err_print(INIT_LOCK_OPEN_ERR,
1563 		    local_lock_file, strerror(errno));
1564 		syseventd_exit(8);
1565 	}
1566 
1567 	lock.l_type = F_WRLCK;
1568 	lock.l_whence = SEEK_SET;
1569 	lock.l_start = 0;
1570 	lock.l_len = 0;
1571 
1572 	if (fcntl(daemon_lock_fd, F_SETLK, &lock) == -1) {
1573 		if (fcntl(daemon_lock_fd, F_GETLK, &lock) == -1) {
1574 			syseventd_err_print(INIT_LOCK_ERR,
1575 			    local_lock_file, strerror(errno));
1576 			exit(2);
1577 		}
1578 		return (lock.l_pid);
1579 	}
1580 	hold_daemon_lock = 1;
1581 
1582 	return (getpid());
1583 }
1584 
1585 /*
1586  * exit_daemon_lock - release the daemon file lock
1587  */
1588 static void
1589 exit_daemon_lock(void)
1590 {
1591 	struct flock lock;
1592 
1593 	lock.l_type = F_UNLCK;
1594 	lock.l_whence = SEEK_SET;
1595 	lock.l_start = 0;
1596 	lock.l_len = 0;
1597 
1598 	if (fcntl(daemon_lock_fd, F_SETLK, &lock) == -1) {
1599 		syseventd_err_print(INIT_UNLOCK_ERR,
1600 		    local_lock_file, strerror(errno));
1601 	}
1602 
1603 	if (close(daemon_lock_fd) == -1) {
1604 		syseventd_err_print(INIT_LOCK_CLOSE_ERR,
1605 		    local_lock_file, strerror(errno));
1606 		exit(-1);
1607 	}
1608 }
1609 
1610 /*
1611  * syseventd_err_print - print error messages to the terminal if not
1612  *			yet daemonized or to syslog.
1613  */
1614 /*PRINTFLIKE1*/
1615 void
1616 syseventd_err_print(char *message, ...)
1617 {
1618 	va_list ap;
1619 
1620 	(void) mutex_lock(&err_mutex);
1621 	va_start(ap, message);
1622 
1623 	if (logflag) {
1624 		(void) vsyslog(LOG_ERR, message, ap);
1625 	} else {
1626 		(void) fprintf(stderr, "%s: ", prog);
1627 		(void) vfprintf(stderr, message, ap);
1628 	}
1629 	va_end(ap);
1630 	(void) mutex_unlock(&err_mutex);
1631 }
1632 
1633 /*
1634  * syseventd_print -  print messages to the terminal or to syslog
1635  *			the following levels are implemented:
1636  *
1637  * 1 - transient errors that does not affect normal program flow
1638  * 2 - upcall/dispatch interaction
1639  * 3 - program flow trace as each message goes through the daemon
1640  * 8 - all the nit-gritty details of startup and shutdown
1641  * 9 - very verbose event flow tracing (no daemonization of syseventd)
1642  *
1643  */
1644 /*PRINTFLIKE2*/
1645 void
1646 syseventd_print(int level, char *message, ...)
1647 {
1648 	va_list ap;
1649 	static int newline = 1;
1650 
1651 	if (level > debug_level) {
1652 		return;
1653 	}
1654 
1655 	(void) mutex_lock(&err_mutex);
1656 	va_start(ap, message);
1657 	if (logflag) {
1658 		(void) syslog(LOG_DEBUG, "%s[%ld]: ",
1659 		    prog, getpid());
1660 		(void) vsyslog(LOG_DEBUG, message, ap);
1661 	} else {
1662 		if (newline) {
1663 			(void) fprintf(stdout, "%s[%ld]: ",
1664 			    prog, getpid());
1665 			(void) vfprintf(stdout, message, ap);
1666 		} else {
1667 			(void) vfprintf(stdout, message, ap);
1668 		}
1669 	}
1670 	if (message[strlen(message)-1] == '\n') {
1671 		newline = 1;
1672 	} else {
1673 		newline = 0;
1674 	}
1675 	va_end(ap);
1676 	(void) mutex_unlock(&err_mutex);
1677 }
1678