xref: /illumos-gate/usr/src/cmd/syseventd/daemons/syseventd/syseventd.c (revision 581cede61ac9c14d8d4ea452562a567189eead78)
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 			/* No need to abort on a SIGCLD */
230 			break;
231 		default:
232 			syseventd_err_print(FATAL_ERROR);
233 			abort();
234 
235 	}
236 }
237 
238 /*
239  * Daemon parent process only.
240  * Child process signal to indicate successful daemon initialization.
241  * This is the normal and expected exit path of the daemon parent.
242  */
243 /*ARGSUSED*/
244 static void
245 sigusr1(int sig)
246 {
247 	syseventd_exit(0);
248 }
249 
250 static void
251 sigwait_thr()
252 {
253 	int	sig;
254 	int	err;
255 	sigset_t signal_set;
256 
257 	for (;;) {
258 		syseventd_print(3, "sigwait thread waiting for signal\n");
259 		(void) sigfillset(&signal_set);
260 		err = sigwait(&signal_set, &sig);
261 		if (err) {
262 			syseventd_exit(2);
263 		}
264 
265 		/*
266 		 * Block all signals until the signal handler completes
267 		 */
268 		if (sig == SIGHUP) {
269 			hup_handler(sig);
270 		} else {
271 			flt_handler(sig);
272 		}
273 	}
274 	/* NOTREACHED */
275 }
276 
277 static void
278 set_root_dir(char *dir)
279 {
280 	root_dir = malloc(strlen(dir) + 1);
281 	if (root_dir == NULL) {
282 		syseventd_err_print(INIT_ROOT_DIR_ERR, strerror(errno));
283 		syseventd_exit(2);
284 	}
285 	(void) strcpy(root_dir, dir);
286 }
287 
288 int
289 main(int argc, char **argv)
290 {
291 	int i, c;
292 	int fd;
293 	pid_t pid;
294 	int has_forked = 0;
295 	extern char *optarg;
296 
297 	(void) setlocale(LC_ALL, "");
298 	(void) textdomain(TEXT_DOMAIN);
299 
300 	if (getuid() != 0) {
301 		(void) fprintf(stderr, "Must be root to run syseventd\n");
302 		syseventd_exit(1);
303 	}
304 
305 	if (argc > 5) {
306 		usage();
307 	}
308 
309 	if ((prog = strrchr(argv[0], '/')) == NULL) {
310 		prog = argv[0];
311 	} else {
312 		prog++;
313 	}
314 
315 	while ((c = getopt(argc, argv, "d:r:")) != EOF) {
316 		switch (c) {
317 		case 'd':
318 			debug_level = atoi(optarg);
319 			break;
320 		case 'r':
321 			/*
322 			 * Private flag for suninstall to run
323 			 * daemon during install.
324 			 */
325 			set_root_dir(optarg);
326 			break;
327 		case '?':
328 		default:
329 			usage();
330 		}
331 	}
332 
333 	/* demonize ourselves */
334 	if (debug_level < DEBUG_LEVEL_FORK) {
335 
336 		sigset_t mask;
337 
338 		(void) sigset(SIGUSR1, sigusr1);
339 
340 		(void) sigemptyset(&mask);
341 		(void) sigaddset(&mask, SIGUSR1);
342 		(void) sigprocmask(SIG_BLOCK, &mask, NULL);
343 
344 		if ((pid = fork()) == (pid_t)-1) {
345 			(void) fprintf(stderr,
346 			    "syseventd: fork failed - %s\n", strerror(errno));
347 			syseventd_exit(1);
348 		}
349 
350 		if (pid != 0) {
351 			/*
352 			 * parent
353 			 * handshake with the daemon so that dependents
354 			 * of the syseventd service don't start up until
355 			 * the service is actually functional
356 			 */
357 			int status;
358 			(void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
359 
360 			if (waitpid(pid, &status, 0) != pid) {
361 				/*
362 				 * child process signal indicating
363 				 * successful daemon initialization
364 				 */
365 				syseventd_exit(0);
366 			}
367 			/* child exited implying unsuccessful startup */
368 			syseventd_exit(1);
369 		}
370 
371 		/* child */
372 
373 		has_forked = 1;
374 		(void) sigset(SIGUSR1, SIG_DFL);
375 		(void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
376 
377 		(void) chdir("/");
378 		(void) setsid();
379 		if (debug_level <= 1) {
380 			closefrom(0);
381 			fd = open("/dev/null", 0);
382 			(void) dup2(fd, 1);
383 			(void) dup2(fd, 2);
384 			logflag = 1;
385 		}
386 	}
387 
388 	openlog("syseventd", LOG_PID, LOG_DAEMON);
389 
390 	(void) mutex_init(&err_mutex, USYNC_THREAD, NULL);
391 
392 	syseventd_print(8,
393 	    "syseventd started, debug level = %d\n", debug_level);
394 
395 	/* only one instance of syseventd can run at a time */
396 	if ((pid = enter_daemon_lock()) != getpid()) {
397 		syseventd_print(1,
398 		    "event daemon pid %ld already running\n", pid);
399 		exit(3);
400 	}
401 
402 	/* initialize semaphores and eventbuf */
403 	(void) sema_init(&sema_eventbuf, SE_EVENT_DISPATCH_CNT,
404 	    USYNC_THREAD, NULL);
405 	(void) sema_init(&sema_dispatch, 0, USYNC_THREAD, NULL);
406 	(void) sema_init(&sema_resource, SE_EVENT_DISPATCH_CNT,
407 	    USYNC_THREAD, NULL);
408 	(void) cond_init(&event_comp_cv, USYNC_THREAD, NULL);
409 	eventbuf = (sysevent_t **)calloc(SE_EVENT_DISPATCH_CNT,
410 	    sizeof (sysevent_t *));
411 	if (eventbuf == NULL) {
412 		syseventd_print(1, "Unable to allocate event buffer array\n");
413 		exit(2);
414 	}
415 	for (i = 0; i < SE_EVENT_DISPATCH_CNT; ++i) {
416 		eventbuf[i] = malloc(LOGEVENT_BUFSIZE);
417 		if (eventbuf[i] == NULL) {
418 			syseventd_print(1, "Unable to allocate event "
419 			    "buffers\n");
420 			exit(2);
421 		}
422 	}
423 
424 	(void) mutex_init(&client_tbl_lock, USYNC_THREAD, NULL);
425 	(void) mutex_init(&ev_comp_lock, USYNC_THREAD, NULL);
426 	(void) mutex_init(&door_lock, USYNC_THREAD, NULL);
427 	(void) rwlock_init(&mod_unload_lock, USYNC_THREAD, NULL);
428 
429 	event_compq = NULL;
430 
431 	syseventd_print(8, "start the message thread running\n");
432 
433 	/*
434 	 * Block all signals to all threads include the main thread.
435 	 * The sigwait_thr thread will process any signals and initiate
436 	 * a graceful recovery if possible.
437 	 */
438 	if (se_signal_blockall() < 0) {
439 		syseventd_err_print(INIT_SIG_BLOCK_ERR);
440 		syseventd_exit(2);
441 	}
442 
443 	if (thr_create(NULL, NULL, (void *(*)(void *))dispatch_message,
444 	    (void *)0, 0, NULL) < 0) {
445 		syseventd_err_print(INIT_THR_CREATE_ERR, strerror(errno));
446 		syseventd_exit(2);
447 	}
448 	if (thr_create(NULL, NULL,
449 	    (void *(*)(void *))event_completion_thr, NULL,
450 	    THR_BOUND, NULL) != 0) {
451 		syseventd_err_print(INIT_THR_CREATE_ERR, strerror(errno));
452 		syseventd_exit(2);
453 	}
454 	/* Create signal catching thread */
455 	if (thr_create(NULL, NULL, (void *(*)(void *))sigwait_thr,
456 	    NULL, 0, NULL) < 0) {
457 		syseventd_err_print(INIT_THR_CREATE_ERR, strerror(errno));
458 		syseventd_exit(2);
459 	}
460 
461 	setbuf(stdout, (char *)NULL);
462 
463 	/* Initialize and load SLM clients */
464 	initialize_client_tbl();
465 	syseventd_init();
466 
467 	/* signal parent to indicate successful daemon initialization */
468 	if (has_forked) {
469 		if (kill(getppid(), SIGUSR1) != 0) {
470 			syseventd_err_print(
471 			    "signal to the parent failed - %s\n",
472 			    strerror(errno));
473 			syseventd_exit(2);
474 		}
475 	}
476 
477 	syseventd_print(8, "Pausing\n");
478 
479 	for (;;) {
480 		(void) pause();
481 	}
482 	/* NOTREACHED */
483 	return (0);
484 }
485 
486 /*
487  * door_upcall - called from the kernel via kernel sysevent door
488  *		to upload event(s).
489  *
490  *		This routine should never block.  If resources are
491  *		not available to immediately accept the event buffer
492  *		EAGAIN is returned to the kernel.
493  *
494  *		Once resources are available, the kernel is notified
495  *		via a modctl interface to resume event delivery to
496  *		syseventd.
497  *
498  */
499 /*ARGSUSED*/
500 static void
501 door_upcall(void *cookie, char *args, size_t alen,
502     door_desc_t *ddp, uint_t ndid)
503 {
504 	sysevent_t *ev;
505 	int rval;
506 
507 
508 	(void) mutex_lock(&door_lock);
509 	if (args == NULL) {
510 		rval = EINVAL;
511 	} else if (sema_trywait(&sema_eventbuf)) {
512 		ev = (sysevent_t *)
513 		    &((log_event_upcall_arg_t *)(void *)args)->buf;
514 		syseventd_print(2, "door_upcall: busy event %llx "
515 		    "retry\n", sysevent_get_seq(ev));
516 		rval = door_upcall_retval = EAGAIN;
517 	} else {
518 		/*
519 		 * Copy received message to local buffer.
520 		 */
521 		size_t size;
522 		ev = (sysevent_t *)
523 		    &((log_event_upcall_arg_t *)(void *)args)->buf;
524 
525 		syseventd_print(2, "door_upcall: event %llx in eventbuf %d\n",
526 		    sysevent_get_seq(ev), deliver_buf);
527 		size = sysevent_get_size(ev) > LOGEVENT_BUFSIZE ?
528 		    LOGEVENT_BUFSIZE : sysevent_get_size(ev);
529 		(void) bcopy(ev, eventbuf[deliver_buf], size);
530 		deliver_buf = (deliver_buf + 1) % SE_EVENT_DISPATCH_CNT;
531 		rval = 0;
532 		(void) sema_post(&sema_dispatch);
533 	}
534 
535 	(void) mutex_unlock(&door_lock);
536 
537 	/*
538 	 * Filling in return values for door_return
539 	 */
540 	(void) door_return((void *)&rval, sizeof (rval), NULL, 0);
541 	(void) door_return(NULL, 0, NULL, 0);
542 }
543 
544 /*
545  * dispatch_message - dispatch message thread
546  *			This thread spins until an event buffer is delivered
547  *			delivered from the kernel.
548  *
549  *			It will wait to dispatch an event to any clients
550  *			until adequate resources are available to process
551  *			the event buffer.
552  */
553 static void
554 dispatch_message(void)
555 {
556 	int error;
557 
558 	for (;;) {
559 		syseventd_print(3, "dispatch_message: thread started\n");
560 		/*
561 		 * Spin till a message comes
562 		 */
563 		while (sema_wait(&sema_dispatch) != 0) {
564 			syseventd_print(1,
565 			    "dispatch_message: sema_wait failed\n");
566 			(void) sleep(1);
567 		}
568 
569 		syseventd_print(3, "dispatch_message: sema_dispatch\n");
570 
571 		/*
572 		 * Wait for available resources
573 		 */
574 		while (sema_wait(&sema_resource) != 0) {
575 			syseventd_print(1, "dispatch_message: sema_wait "
576 			    "failed\n");
577 			(void) sleep(1);
578 		}
579 
580 		syseventd_print(2, "dispatch_message: eventbuf %d\n",
581 		    dispatch_buf);
582 
583 		/*
584 		 * Client dispatch
585 		 */
586 		do {
587 			error = dispatch();
588 		} while (error == EAGAIN);
589 
590 		syseventd_print(2, "eventbuf %d dispatched\n", dispatch_buf);
591 		dispatch_buf = (dispatch_buf + 1) % SE_EVENT_DISPATCH_CNT;
592 
593 		/*
594 		 * kernel received a busy signal -
595 		 * kickstart the kernel delivery thread
596 		 * door_lock blocks the kernel so we hold it for the
597 		 * shortest time possible.
598 		 */
599 		(void) mutex_lock(&door_lock);
600 		if (door_upcall_retval == EAGAIN && !fini_pending) {
601 			syseventd_print(3, "dispatch_message: retrigger "
602 			    "door_upcall_retval = %d\n",
603 			    door_upcall_retval);
604 			(void) modctl(MODEVENTS, (uintptr_t)MODEVENTS_FLUSH,
605 			    NULL, NULL, NULL, 0);
606 			door_upcall_retval = 0;
607 		}
608 		(void) mutex_unlock(&door_lock);
609 	}
610 	/* NOTREACHED */
611 }
612 
613 /*
614  * drain_eventq - Called to drain all pending events from the client's
615  *		event queue.
616  */
617 static void
618 drain_eventq(struct sysevent_client *scp, int status)
619 {
620 	struct event_dispatch_pkg *d_pkg;
621 	struct event_dispatchq *eventq, *eventq_next;
622 
623 	syseventd_print(3, "Draining eventq for client %d\n",
624 	    scp->client_num);
625 
626 	eventq = scp->eventq;
627 	while (eventq) {
628 		/*
629 		 * Mark all dispatched events as completed, but indicate the
630 		 * error status
631 		 */
632 		d_pkg = eventq->d_pkg;
633 
634 		syseventd_print(4, "drain event 0X%llx for client %d\n",
635 		    sysevent_get_seq(d_pkg->ev), scp->client_num);
636 
637 		if (d_pkg->completion_state == SE_NOT_DISPATCHED) {
638 			d_pkg->completion_status = status;
639 			d_pkg->completion_state = SE_COMPLETE;
640 			(void) sema_post(d_pkg->completion_sema);
641 		}
642 
643 		eventq_next = eventq->next;
644 		free(eventq);
645 		eventq = eventq_next;
646 		scp->eventq = eventq;
647 	}
648 }
649 
650 /*
651  * client_deliver_event_thr - Client delivery thread
652  *				This thread will process any events on this
653  *				client's eventq.
654  */
655 static void
656 client_deliver_event_thr(void *arg)
657 {
658 	int flag, error, i;
659 	sysevent_t *ev;
660 	hrtime_t now;
661 	module_t *mod;
662 	struct event_dispatchq *eventq;
663 	struct sysevent_client *scp;
664 	struct event_dispatch_pkg *d_pkg;
665 
666 	scp = (struct sysevent_client *)arg;
667 	mod = (module_t *)scp->client_data;
668 
669 	(void) mutex_lock(&scp->client_lock);
670 	for (;;) {
671 		while (scp->eventq == NULL) {
672 
673 			/*
674 			 * Client has been suspended or unloaded, go no further.
675 			 */
676 			if (fini_pending) {
677 				scp->client_flags &= ~SE_CLIENT_THR_RUNNING;
678 				syseventd_print(3, "Client %d delivery thread "
679 				    "exiting flags: 0X%x\n",
680 				    scp->client_num, scp->client_flags);
681 				(void) mutex_unlock(&scp->client_lock);
682 				return;
683 			}
684 
685 			(void) cond_wait(&scp->client_cv, &scp->client_lock);
686 
687 		}
688 
689 		/*
690 		 * Process events from the head of the eventq, eventq is locked
691 		 * going into the processing.
692 		 */
693 		eventq = scp->eventq;
694 		while (eventq != NULL) {
695 			d_pkg = eventq->d_pkg;
696 			d_pkg->completion_state = SE_OUTSTANDING;
697 			scp->eventq = eventq->next;
698 			free(eventq);
699 			eventq = scp->eventq;
700 			(void) mutex_unlock(&scp->client_lock);
701 
702 
703 			flag = error = 0;
704 			ev = d_pkg->ev;
705 
706 			syseventd_print(3, "Start delivery for client %d "
707 			    "with retry count %d\n",
708 			    scp->client_num, d_pkg->retry_count);
709 
710 			/*
711 			 * Retry limit has been reached by this client, indicate
712 			 * that no further retries are allowed
713 			 */
714 			for (i = 0; i <= scp->retry_limit; ++i) {
715 				if (i == scp->retry_limit)
716 					flag = SE_NO_RETRY;
717 
718 				/* Start the clock for the event delivery */
719 				d_pkg->start_time = gethrtime();
720 
721 				syseventd_print(9, "Deliver to module client "
722 				    "%s\n", mod->name);
723 
724 				error = mod->deliver_event(ev, flag);
725 
726 				/* Can not allow another retry */
727 				if (i == scp->retry_limit)
728 					error = 0;
729 
730 				/* Stop the clock */
731 				now = gethrtime();
732 
733 				/*
734 				 * Suspend event processing and drain the
735 				 * event q for latent clients
736 				 */
737 				if (now - d_pkg->start_time >
738 				    ((hrtime_t)SE_TIMEOUT * NANOSEC)) {
739 					syseventd_print(1, "Unresponsive "
740 					    "client %d: Draining eventq and "
741 					    "suspending event delivery\n",
742 					    scp->client_num);
743 					(void) mutex_lock(&scp->client_lock);
744 					scp->client_flags &=
745 					    ~SE_CLIENT_THR_RUNNING;
746 					scp->client_flags |=
747 					    SE_CLIENT_SUSPENDED;
748 
749 					/* Cleanup current event */
750 					d_pkg->completion_status = EFAULT;
751 					d_pkg->completion_state = SE_COMPLETE;
752 					(void) sema_post(
753 					    d_pkg->completion_sema);
754 
755 					/*
756 					 * Drain the remaining events from the
757 					 * queue.
758 					 */
759 					drain_eventq(scp, EINVAL);
760 					(void) mutex_unlock(&scp->client_lock);
761 					return;
762 				}
763 
764 				/* Event delivery retry requested */
765 				if (fini_pending || error != EAGAIN) {
766 					break;
767 				} else {
768 					(void) sleep(SE_RETRY_TIME);
769 				}
770 			}
771 
772 			(void) mutex_lock(&scp->client_lock);
773 			d_pkg->completion_status = error;
774 			d_pkg->completion_state = SE_COMPLETE;
775 			(void) sema_post(d_pkg->completion_sema);
776 			syseventd_print(3, "Completed delivery with "
777 			    "error %d\n", error);
778 		}
779 
780 		syseventd_print(3, "No more events to process for client %d\n",
781 		    scp->client_num);
782 
783 		/* Return if this was a synchronous delivery */
784 		if (!SE_CLIENT_IS_THR_RUNNING(scp)) {
785 			(void) mutex_unlock(&scp->client_lock);
786 			return;
787 		}
788 
789 	}
790 }
791 
792 /*
793  * client_deliver_event - Client specific event delivery
794  *			This routine will allocate and initialize the
795  *			neccessary per-client dispatch data.
796  *
797  *			If the eventq is not empty, it may be assumed that
798  *			a delivery thread exists for this client and the
799  *			dispatch data is appended to the eventq.
800  *
801  *			The dispatch package is freed by the event completion
802  *			thread (event_completion_thr) and the eventq entry
803  *			is freed by the event delivery thread.
804  */
805 static struct event_dispatch_pkg *
806 client_deliver_event(struct sysevent_client *scp, sysevent_t *ev,
807 	sema_t *completion_sema)
808 {
809 	size_t ev_sz = sysevent_get_size(ev);
810 	struct event_dispatchq *newq, *tmp;
811 	struct event_dispatch_pkg *d_pkg;
812 
813 	syseventd_print(3, "client_deliver_event: id 0x%llx size %d\n",
814 	    (longlong_t)sysevent_get_seq(ev), ev_sz);
815 	if (debug_level == 9) {
816 		se_print(stdout, ev);
817 	}
818 
819 	/*
820 	 * Check for suspended client
821 	 */
822 	(void) mutex_lock(&scp->client_lock);
823 	if (SE_CLIENT_IS_SUSPENDED(scp) || !SE_CLIENT_IS_THR_RUNNING(scp)) {
824 		(void) mutex_unlock(&scp->client_lock);
825 		return (NULL);
826 	}
827 
828 	/*
829 	 * Allocate a new dispatch package and eventq entry
830 	 */
831 	newq = (struct event_dispatchq *)malloc(
832 	    sizeof (struct event_dispatchq));
833 	if (newq == NULL) {
834 		(void) mutex_unlock(&scp->client_lock);
835 		return (NULL);
836 	}
837 
838 	d_pkg = (struct event_dispatch_pkg *)malloc(
839 	    sizeof (struct event_dispatch_pkg));
840 	if (d_pkg == NULL) {
841 		free(newq);
842 		(void) mutex_unlock(&scp->client_lock);
843 		return (NULL);
844 	}
845 
846 	/* Initialize the dispatch package */
847 	d_pkg->scp = scp;
848 	d_pkg->retry_count = 0;
849 	d_pkg->completion_status = 0;
850 	d_pkg->completion_state = SE_NOT_DISPATCHED;
851 	d_pkg->completion_sema = completion_sema;
852 	d_pkg->ev = ev;
853 	newq->d_pkg = d_pkg;
854 	newq->next = NULL;
855 
856 	if (scp->eventq != NULL) {
857 
858 		/* Add entry to the end of the eventq */
859 		tmp = scp->eventq;
860 		while (tmp->next != NULL)
861 			tmp = tmp->next;
862 		tmp->next = newq;
863 	} else {
864 		/* event queue empty, wakeup delivery thread */
865 		scp->eventq = newq;
866 		(void) cond_signal(&scp->client_cv);
867 	}
868 	(void) mutex_unlock(&scp->client_lock);
869 
870 	return (d_pkg);
871 }
872 
873 /*
874  * event_completion_thr - Event completion thread.  This thread routine
875  *			waits for all client delivery thread to complete
876  *			delivery of a particular event.
877  */
878 static void
879 event_completion_thr()
880 {
881 	int ret, i, client_count, ok_to_free;
882 	sysevent_id_t eid;
883 	struct sysevent_client *scp;
884 	struct ev_completion *ev_comp;
885 	struct event_dispatchq *dispatchq;
886 	struct event_dispatch_pkg *d_pkg;
887 
888 	(void) mutex_lock(&ev_comp_lock);
889 	for (;;) {
890 		while (event_compq == NULL) {
891 			(void) cond_wait(&event_comp_cv, &ev_comp_lock);
892 		}
893 
894 		/*
895 		 * Process event completions from the head of the
896 		 * completion queue
897 		 */
898 		ev_comp = event_compq;
899 		while (ev_comp) {
900 			(void) mutex_unlock(&ev_comp_lock);
901 			eid.eid_seq = sysevent_get_seq(ev_comp->ev);
902 			sysevent_get_time(ev_comp->ev, &eid.eid_ts);
903 			client_count = ev_comp->client_count;
904 			ok_to_free = 1;
905 
906 			syseventd_print(3, "Wait for event completion of "
907 			    "event 0X%llx on %d clients\n",
908 			    eid.eid_seq, client_count);
909 
910 			while (client_count) {
911 				syseventd_print(9, "Waiting for %d clients on "
912 				    "event id 0X%llx\n", client_count,
913 				    eid.eid_seq);
914 
915 				(void) sema_wait(&ev_comp->client_sema);
916 				--client_count;
917 			}
918 
919 			syseventd_print(3, "Cleaning up clients for event "
920 			    "0X%llx\n", eid.eid_seq);
921 			dispatchq = ev_comp->dispatch_list;
922 			while (dispatchq != NULL) {
923 				d_pkg = dispatchq->d_pkg;
924 				scp = d_pkg->scp;
925 
926 				if (d_pkg->completion_status == EAGAIN)
927 					ok_to_free = 0;
928 
929 				syseventd_print(4, "Delivery of 0X%llx "
930 				    "complete for client %d retry count %d "
931 				    "status %d\n", eid.eid_seq,
932 				    scp->client_num,
933 				    d_pkg->retry_count,
934 				    d_pkg->completion_status);
935 
936 				free(d_pkg);
937 				ev_comp->dispatch_list = dispatchq->next;
938 				free(dispatchq);
939 				dispatchq = ev_comp->dispatch_list;
940 			}
941 
942 			if (ok_to_free) {
943 				for (i = 0; i < MAX_MODCTL_RETRY; ++i) {
944 					if ((ret = modctl(MODEVENTS,
945 					    (uintptr_t)MODEVENTS_FREEDATA,
946 					    (uintptr_t)&eid, NULL,
947 					    NULL, 0)) != 0) {
948 						syseventd_print(1, "attempting "
949 						    "to free event 0X%llx\n",
950 						    eid.eid_seq);
951 
952 						/*
953 						 * Kernel may need time to
954 						 * move this event buffer to
955 						 * the sysevent sent queue
956 						 */
957 						(void) sleep(1);
958 					} else {
959 						break;
960 					}
961 				}
962 				if (ret) {
963 					syseventd_print(1, "Unable to free "
964 					    "event 0X%llx from the "
965 					    "kernel\n", eid.eid_seq);
966 				}
967 			} else {
968 				syseventd_print(1, "Not freeing event 0X%llx\n",
969 				    eid.eid_seq);
970 			}
971 
972 			syseventd_print(2, "Event delivery complete for id "
973 			    "0X%llx\n", eid.eid_seq);
974 
975 			(void) mutex_lock(&ev_comp_lock);
976 			event_compq = ev_comp->next;
977 			free(ev_comp->ev);
978 			free(ev_comp);
979 			ev_comp = event_compq;
980 			(void) sema_post(&sema_resource);
981 		}
982 
983 		/*
984 		 * Event completion queue is empty, signal possible unload
985 		 * operation
986 		 */
987 		(void) cond_signal(&event_comp_cv);
988 
989 		syseventd_print(3, "No more events\n");
990 	}
991 }
992 
993 /*
994  * dispatch - Dispatch the current event buffer to all valid SLM clients.
995  */
996 static int
997 dispatch(void)
998 {
999 	int ev_sz, i, client_count = 0;
1000 	sysevent_t *new_ev;
1001 	sysevent_id_t eid;
1002 	struct ev_completion *ev_comp, *tmp;
1003 	struct event_dispatchq *dispatchq, *client_list;
1004 	struct event_dispatch_pkg *d_pkg;
1005 
1006 	/* Check for module unload operation */
1007 	if (rw_tryrdlock(&mod_unload_lock) != 0) {
1008 		syseventd_print(2, "unload in progress abort delivery\n");
1009 		(void) sema_post(&sema_eventbuf);
1010 		(void) sema_post(&sema_resource);
1011 		return (0);
1012 	}
1013 
1014 	syseventd_print(3, "deliver dispatch buffer %d", dispatch_buf);
1015 	eid.eid_seq = sysevent_get_seq(eventbuf[dispatch_buf]);
1016 	sysevent_get_time(eventbuf[dispatch_buf], &eid.eid_ts);
1017 	syseventd_print(3, "deliver msg id: 0x%llx\n", eid.eid_seq);
1018 
1019 	/*
1020 	 * ev_comp is used to hold event completion data.  It is freed
1021 	 * by the event completion thread (event_completion_thr).
1022 	 */
1023 	ev_comp = (struct ev_completion *)
1024 	    malloc(sizeof (struct ev_completion));
1025 	if (ev_comp == NULL) {
1026 		(void) rw_unlock(&mod_unload_lock);
1027 		syseventd_print(1, "Can not allocate event completion buffer "
1028 		    "for event id 0X%llx\n", eid.eid_seq);
1029 		return (EAGAIN);
1030 	}
1031 	ev_comp->dispatch_list = NULL;
1032 	ev_comp->next = NULL;
1033 	(void) sema_init(&ev_comp->client_sema, 0, USYNC_THREAD, NULL);
1034 
1035 	ev_sz = sysevent_get_size(eventbuf[dispatch_buf]);
1036 	new_ev = calloc(1, ev_sz);
1037 	if (new_ev == NULL) {
1038 		free(ev_comp);
1039 		(void) rw_unlock(&mod_unload_lock);
1040 		syseventd_print(1, "Can not allocate new event buffer "
1041 		"for event id 0X%llx\n", eid.eid_seq);
1042 		return (EAGAIN);
1043 	}
1044 
1045 
1046 	/*
1047 	 * For long messages, copy additional data from kernel
1048 	 */
1049 	if (ev_sz > LOGEVENT_BUFSIZE) {
1050 		int ret = 0;
1051 
1052 		/* Ok to release eventbuf for next event buffer from kernel */
1053 		(void) sema_post(&sema_eventbuf);
1054 
1055 		for (i = 0; i < MAX_MODCTL_RETRY; ++i) {
1056 			if ((ret = modctl(MODEVENTS,
1057 			    (uintptr_t)MODEVENTS_GETDATA,
1058 			    (uintptr_t)&eid,
1059 			    (uintptr_t)ev_sz,
1060 			    (uintptr_t)new_ev, 0))
1061 			    == 0)
1062 				break;
1063 			else
1064 				(void) sleep(1);
1065 		}
1066 		if (ret) {
1067 			syseventd_print(1, "GET_DATA failed for 0X%llx:%llx\n",
1068 			    eid.eid_ts, eid.eid_seq);
1069 			free(new_ev);
1070 			free(ev_comp);
1071 			(void) rw_unlock(&mod_unload_lock);
1072 			return (EAGAIN);
1073 		}
1074 	} else {
1075 		(void) bcopy(eventbuf[dispatch_buf], new_ev, ev_sz);
1076 		/* Ok to release eventbuf for next event buffer from kernel */
1077 		(void) sema_post(&sema_eventbuf);
1078 	}
1079 
1080 
1081 	/*
1082 	 * Deliver a copy of eventbuf to clients so
1083 	 * eventbuf can be used for the next message
1084 	 */
1085 	for (i = 0; i < MAX_SLM; ++i) {
1086 
1087 		/* Don't bother for suspended or unloaded clients */
1088 		if (!SE_CLIENT_IS_LOADED(sysevent_client_tbl[i]) ||
1089 		    SE_CLIENT_IS_SUSPENDED(sysevent_client_tbl[i]))
1090 			continue;
1091 
1092 		/*
1093 		 * Allocate event dispatch queue entry.  All queue entries
1094 		 * are freed by the event completion thread as client
1095 		 * delivery completes.
1096 		 */
1097 		dispatchq = (struct event_dispatchq *)malloc(
1098 		    sizeof (struct event_dispatchq));
1099 		if (dispatchq == NULL) {
1100 			syseventd_print(1, "Can not allocate dispatch q "
1101 			"for event id 0X%llx client %d\n", eid.eid_seq, i);
1102 			continue;
1103 		}
1104 		dispatchq->next = NULL;
1105 
1106 		/* Initiate client delivery */
1107 		d_pkg = client_deliver_event(sysevent_client_tbl[i],
1108 		    new_ev, &ev_comp->client_sema);
1109 		if (d_pkg == NULL) {
1110 			syseventd_print(1, "Can not allocate dispatch "
1111 			    "package for event id 0X%llx client %d\n",
1112 			    eid.eid_seq, i);
1113 			free(dispatchq);
1114 			continue;
1115 		}
1116 		dispatchq->d_pkg = d_pkg;
1117 		++client_count;
1118 
1119 		if (ev_comp->dispatch_list == NULL) {
1120 			ev_comp->dispatch_list = dispatchq;
1121 			client_list = dispatchq;
1122 		} else {
1123 			client_list->next = dispatchq;
1124 			client_list = client_list->next;
1125 		}
1126 	}
1127 
1128 	ev_comp->client_count = client_count;
1129 	ev_comp->ev = new_ev;
1130 
1131 	(void) mutex_lock(&ev_comp_lock);
1132 
1133 	if (event_compq == NULL) {
1134 		syseventd_print(3, "Wakeup event completion thread for "
1135 		    "id 0X%llx\n", eid.eid_seq);
1136 		event_compq = ev_comp;
1137 		(void) cond_signal(&event_comp_cv);
1138 	} else {
1139 
1140 		/* Add entry to the end of the event completion queue */
1141 		tmp = event_compq;
1142 		while (tmp->next != NULL)
1143 			tmp = tmp->next;
1144 		tmp->next = ev_comp;
1145 		syseventd_print(3, "event added to completion queue for "
1146 		    "id 0X%llx\n", eid.eid_seq);
1147 	}
1148 	(void) mutex_unlock(&ev_comp_lock);
1149 	(void) rw_unlock(&mod_unload_lock);
1150 
1151 	return (0);
1152 }
1153 
1154 #define	MODULE_DIR_HW	"/usr/platform/%s/lib/sysevent/modules/"
1155 #define	MODULE_DIR_GEN	"/usr/lib/sysevent/modules/"
1156 #define	MOD_DIR_NUM	3
1157 static char dirname[MOD_DIR_NUM][MAXPATHLEN];
1158 
1159 static char *
1160 dir_num2name(int dirnum)
1161 {
1162 	char infobuf[MAXPATHLEN];
1163 
1164 	if (dirnum >= MOD_DIR_NUM)
1165 		return (NULL);
1166 
1167 	if (dirname[0][0] == '\0') {
1168 		if (sysinfo(SI_PLATFORM, infobuf, MAXPATHLEN) == -1) {
1169 			syseventd_print(1, "dir_num2name: "
1170 			    "sysinfo error %s\n", strerror(errno));
1171 			return (NULL);
1172 		} else if (snprintf(dirname[0], sizeof (dirname[0]),
1173 		    MODULE_DIR_HW, infobuf) >= sizeof (dirname[0])) {
1174 			syseventd_print(1, "dir_num2name: "
1175 			    "platform name too long: %s\n",
1176 			    infobuf);
1177 			return (NULL);
1178 		}
1179 		if (sysinfo(SI_MACHINE, infobuf, MAXPATHLEN) == -1) {
1180 			syseventd_print(1, "dir_num2name: "
1181 			    "sysinfo error %s\n", strerror(errno));
1182 			return (NULL);
1183 		} else if (snprintf(dirname[1], sizeof (dirname[1]),
1184 		    MODULE_DIR_HW, infobuf) >= sizeof (dirname[1])) {
1185 			syseventd_print(1, "dir_num2name: "
1186 			    "machine name too long: %s\n",
1187 			    infobuf);
1188 			return (NULL);
1189 		}
1190 		(void) strcpy(dirname[2], MODULE_DIR_GEN);
1191 	}
1192 
1193 	return (dirname[dirnum]);
1194 }
1195 
1196 
1197 /*
1198  * load_modules - Load modules found in the common syseventd module directories
1199  *		Modules that do not provide valid interfaces are rejected.
1200  */
1201 static void
1202 load_modules(char *dirname)
1203 {
1204 	int client_id;
1205 	DIR *mod_dir;
1206 	module_t *mod;
1207 	struct dirent *entp;
1208 	struct slm_mod_ops *mod_ops;
1209 	struct sysevent_client *scp;
1210 
1211 	if (dirname == NULL)
1212 		return;
1213 
1214 	/* Return silently if module directory does not exist */
1215 	if ((mod_dir = opendir(dirname)) == NULL) {
1216 		syseventd_print(1, "Unable to open module directory %s: %s\n",
1217 		    dirname, strerror(errno));
1218 		return;
1219 	}
1220 
1221 	syseventd_print(3, "loading modules from %s\n", dirname);
1222 
1223 	/*
1224 	 * Go through directory, looking for files ending with .so
1225 	 */
1226 	while ((entp = readdir(mod_dir)) != NULL) {
1227 		void *dlh, *f;
1228 		char *tmp, modpath[MAXPATHLEN];
1229 
1230 		if (((tmp = strstr(entp->d_name, MODULE_SUFFIX)) == NULL) ||
1231 		    (tmp[strlen(MODULE_SUFFIX)] != '\0')) {
1232 			continue;
1233 		}
1234 
1235 		if (snprintf(modpath, sizeof (modpath), "%s%s",
1236 		    dirname, entp->d_name) >= sizeof (modpath)) {
1237 			syseventd_err_print(INIT_PATH_ERR, modpath);
1238 			continue;
1239 		}
1240 		if ((dlh = dlopen(modpath, RTLD_LAZY)) == NULL) {
1241 			syseventd_err_print(LOAD_MOD_DLOPEN_ERR,
1242 			    modpath, dlerror());
1243 			continue;
1244 		} else if ((f = dlsym(dlh, EVENT_INIT)) == NULL) {
1245 			syseventd_err_print(LOAD_MOD_NO_INIT,
1246 			    modpath, dlerror());
1247 			(void) dlclose(dlh);
1248 			continue;
1249 		}
1250 
1251 		mod = malloc(sizeof (*mod));
1252 		if (mod == NULL) {
1253 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "mod",
1254 			    strerror(errno));
1255 			(void) dlclose(dlh);
1256 			continue;
1257 		}
1258 
1259 		mod->name = strdup(entp->d_name);
1260 		if (mod->name == NULL) {
1261 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "mod->name",
1262 			    strerror(errno));
1263 			(void) dlclose(dlh);
1264 			free(mod);
1265 			continue;
1266 		}
1267 
1268 		mod->dlhandle = dlh;
1269 		mod->event_mod_init = (struct slm_mod_ops *(*)())f;
1270 
1271 		/* load in other module functions */
1272 		mod->event_mod_fini = (void (*)())dlsym(dlh, EVENT_FINI);
1273 		if (mod->event_mod_fini == NULL) {
1274 			syseventd_err_print(LOAD_MOD_DLSYM_ERR, mod->name,
1275 			    dlerror());
1276 			free(mod->name);
1277 			free(mod);
1278 			(void) dlclose(dlh);
1279 			continue;
1280 		}
1281 
1282 		/* Call module init routine */
1283 		if ((mod_ops = mod->event_mod_init()) == NULL) {
1284 			syseventd_err_print(LOAD_MOD_EINVAL, mod->name);
1285 			free(mod->name);
1286 			free(mod);
1287 			(void) dlclose(dlh);
1288 			continue;
1289 		}
1290 		if (mod_ops->major_version != SE_MAJOR_VERSION) {
1291 			syseventd_err_print(LOAD_MOD_VERSION_MISMATCH,
1292 			    mod->name, SE_MAJOR_VERSION,
1293 			    mod_ops->major_version);
1294 			mod->event_mod_fini();
1295 			free(mod->name);
1296 			free(mod);
1297 			(void) dlclose(dlh);
1298 			continue;
1299 		}
1300 
1301 		mod->deliver_event = mod_ops->deliver_event;
1302 		/* Add module entry to client list */
1303 		if ((client_id = insert_client((void *)mod, SLM_CLIENT,
1304 		    (mod_ops->retry_limit <= SE_MAX_RETRY_LIMIT ?
1305 		    mod_ops->retry_limit : SE_MAX_RETRY_LIMIT))) < 0) {
1306 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "insert_client",
1307 			    strerror(errno));
1308 			mod->event_mod_fini();
1309 			free(mod->name);
1310 			free(mod);
1311 			(void) dlclose(dlh);
1312 			continue;
1313 		}
1314 
1315 		scp = sysevent_client_tbl[client_id];
1316 		++concurrency_level;
1317 		(void) thr_setconcurrency(concurrency_level);
1318 		if (thr_create(NULL, 0,
1319 		    (void *(*)(void *))client_deliver_event_thr,
1320 		    (void *)scp, THR_BOUND, &scp->tid) != 0) {
1321 
1322 			syseventd_err_print(LOAD_MOD_ALLOC_ERR, "insert_client",
1323 			    strerror(errno));
1324 			mod->event_mod_fini();
1325 			free(mod->name);
1326 			free(mod);
1327 			(void) dlclose(dlh);
1328 			continue;
1329 		}
1330 		scp->client_flags |= SE_CLIENT_THR_RUNNING;
1331 
1332 		syseventd_print(3, "loaded module %s\n", entp->d_name);
1333 	}
1334 
1335 	(void) closedir(mod_dir);
1336 	syseventd_print(3, "modules loaded\n");
1337 }
1338 
1339 /*
1340  * unload_modules - modules are unloaded prior to graceful shutdown or
1341  *			before restarting the daemon upon receipt of
1342  *			SIGHUP.
1343  */
1344 static void
1345 unload_modules(int sig)
1346 {
1347 	int			i, count, done;
1348 	module_t		*mod;
1349 	struct sysevent_client	*scp;
1350 
1351 	/*
1352 	 * unload modules that are ready, skip those that have not
1353 	 * drained their event queues.
1354 	 */
1355 	count = done = 0;
1356 	while (done < MAX_SLM) {
1357 		/* Don't wait indefinitely for unresponsive clients */
1358 		if (sig != SIGHUP && count > SE_TIMEOUT) {
1359 			break;
1360 		}
1361 
1362 		done = 0;
1363 
1364 		/* Shutdown clients */
1365 		for (i = 0; i < MAX_SLM; ++i) {
1366 			scp = sysevent_client_tbl[i];
1367 			if (mutex_trylock(&scp->client_lock) == 0) {
1368 				if (scp->client_type != SLM_CLIENT ||
1369 				    scp->client_data == NULL) {
1370 					(void) mutex_unlock(&scp->client_lock);
1371 					done++;
1372 					continue;
1373 				}
1374 			} else {
1375 				syseventd_print(3, "Skipping unload of "
1376 				    "client %d: client locked\n",
1377 				    scp->client_num);
1378 				continue;
1379 			}
1380 
1381 			/*
1382 			 * Drain the eventq and wait for delivery thread to
1383 			 * cleanly exit
1384 			 */
1385 			drain_eventq(scp, EAGAIN);
1386 			(void) cond_signal(&scp->client_cv);
1387 			(void) mutex_unlock(&scp->client_lock);
1388 			(void) thr_join(scp->tid, NULL, NULL);
1389 
1390 			/*
1391 			 * It is now safe to unload the module
1392 			 */
1393 			mod = (module_t *)scp->client_data;
1394 			syseventd_print(2, "Unload %s\n", mod->name);
1395 			mod->event_mod_fini();
1396 			(void) dlclose(mod->dlhandle);
1397 			free(mod->name);
1398 			(void) mutex_lock(&client_tbl_lock);
1399 			delete_client(i);
1400 			(void) mutex_unlock(&client_tbl_lock);
1401 			++done;
1402 
1403 		}
1404 		++count;
1405 		(void) sleep(1);
1406 	}
1407 
1408 	/*
1409 	 * Wait for event completions
1410 	 */
1411 	syseventd_print(2, "waiting for event completions\n");
1412 	(void) mutex_lock(&ev_comp_lock);
1413 	while (event_compq != NULL) {
1414 		(void) cond_wait(&event_comp_cv, &ev_comp_lock);
1415 	}
1416 	(void) mutex_unlock(&ev_comp_lock);
1417 }
1418 
1419 /*
1420  * syseventd_init - Called at daemon (re)start-up time to load modules
1421  *			and kickstart the kernel delivery engine.
1422  */
1423 static void
1424 syseventd_init()
1425 {
1426 	int i, fd;
1427 	char local_door_file[PATH_MAX + 1];
1428 
1429 	fini_pending = 0;
1430 
1431 	concurrency_level = MIN_CONCURRENCY_LEVEL;
1432 	(void) thr_setconcurrency(concurrency_level);
1433 
1434 	/*
1435 	 * Load client modules for event delivering
1436 	 */
1437 	for (i = 0; i < MOD_DIR_NUM; ++i) {
1438 		load_modules(dir_num2name(i));
1439 	}
1440 
1441 	/*
1442 	 * Create kernel delivery door service
1443 	 */
1444 	syseventd_print(8, "Create a door for kernel upcalls\n");
1445 	if (snprintf(local_door_file, sizeof (local_door_file), "%s%s",
1446 	    root_dir, LOGEVENT_DOOR_UPCALL) >= sizeof (local_door_file)) {
1447 		syseventd_err_print(INIT_PATH_ERR, local_door_file);
1448 		syseventd_exit(5);
1449 	}
1450 
1451 	/*
1452 	 * Remove door file for robustness.
1453 	 */
1454 	if (unlink(local_door_file) != 0)
1455 		syseventd_print(8, "Unlink of %s failed.\n", local_door_file);
1456 
1457 	fd = open(local_door_file, O_CREAT|O_RDWR, S_IREAD|S_IWRITE);
1458 	if ((fd == -1) && (errno != EEXIST)) {
1459 		syseventd_err_print(INIT_OPEN_DOOR_ERR, strerror(errno));
1460 		syseventd_exit(5);
1461 	}
1462 	(void) close(fd);
1463 
1464 	upcall_door = door_create(door_upcall, NULL,
1465 	    DOOR_REFUSE_DESC | DOOR_NO_CANCEL);
1466 	if (upcall_door == -1) {
1467 		syseventd_err_print(INIT_CREATE_DOOR_ERR, strerror(errno));
1468 		syseventd_exit(5);
1469 	}
1470 
1471 	(void) fdetach(local_door_file);
1472 retry:
1473 	if (fattach(upcall_door, local_door_file) != 0) {
1474 		if (errno == EBUSY)
1475 			goto retry;
1476 		syseventd_err_print(INIT_FATTACH_ERR, strerror(errno));
1477 		(void) door_revoke(upcall_door);
1478 		syseventd_exit(5);
1479 	}
1480 
1481 	/*
1482 	 * Tell kernel the door name and start delivery
1483 	 */
1484 	syseventd_print(2,
1485 	    "local_door_file = %s\n", local_door_file);
1486 	if (modctl(MODEVENTS,
1487 	    (uintptr_t)MODEVENTS_SET_DOOR_UPCALL_FILENAME,
1488 	    (uintptr_t)local_door_file, NULL, NULL, 0) < 0) {
1489 		syseventd_err_print(INIT_DOOR_NAME_ERR, strerror(errno));
1490 		syseventd_exit(6);
1491 	}
1492 
1493 	door_upcall_retval = 0;
1494 
1495 	if (modctl(MODEVENTS, (uintptr_t)MODEVENTS_FLUSH, NULL, NULL, NULL, 0)
1496 	    < 0) {
1497 		syseventd_err_print(KERNEL_REPLAY_ERR, strerror(errno));
1498 		syseventd_exit(7);
1499 	}
1500 }
1501 
1502 /*
1503  * syseventd_fini - shut down daemon, but do not exit
1504  */
1505 static void
1506 syseventd_fini(int sig)
1507 {
1508 	/*
1509 	 * Indicate that event queues should be drained and no
1510 	 * additional events be accepted
1511 	 */
1512 	fini_pending = 1;
1513 
1514 	/* Close the kernel event door to halt delivery */
1515 	(void) door_revoke(upcall_door);
1516 
1517 	syseventd_print(1, "Unloading modules\n");
1518 	(void) rw_wrlock(&mod_unload_lock);
1519 	unload_modules(sig);
1520 	(void) rw_unlock(&mod_unload_lock);
1521 
1522 }
1523 
1524 /*
1525  * enter_daemon_lock - lock the daemon file lock
1526  *
1527  * Use an advisory lock to ensure that only one daemon process is active
1528  * in the system at any point in time.	If the lock is held by another
1529  * process, do not block but return the pid owner of the lock to the
1530  * caller immediately.	The lock is cleared if the holding daemon process
1531  * exits for any reason even if the lock file remains, so the daemon can
1532  * be restarted if necessary.  The lock file is DAEMON_LOCK_FILE.
1533  */
1534 static pid_t
1535 enter_daemon_lock(void)
1536 {
1537 	struct flock	lock;
1538 
1539 	syseventd_print(8, "enter_daemon_lock: lock file = %s\n",
1540 	    DAEMON_LOCK_FILE);
1541 
1542 	if (snprintf(local_lock_file, sizeof (local_lock_file), "%s%s",
1543 	    root_dir, DAEMON_LOCK_FILE) >= sizeof (local_lock_file)) {
1544 		syseventd_err_print(INIT_PATH_ERR, local_lock_file);
1545 		syseventd_exit(8);
1546 	}
1547 	daemon_lock_fd = open(local_lock_file, O_CREAT|O_RDWR, 0644);
1548 	if (daemon_lock_fd < 0) {
1549 		syseventd_err_print(INIT_LOCK_OPEN_ERR,
1550 		    local_lock_file, strerror(errno));
1551 		syseventd_exit(8);
1552 	}
1553 
1554 	lock.l_type = F_WRLCK;
1555 	lock.l_whence = SEEK_SET;
1556 	lock.l_start = 0;
1557 	lock.l_len = 0;
1558 
1559 	if (fcntl(daemon_lock_fd, F_SETLK, &lock) == -1) {
1560 		if (fcntl(daemon_lock_fd, F_GETLK, &lock) == -1) {
1561 			syseventd_err_print(INIT_LOCK_ERR,
1562 			    local_lock_file, strerror(errno));
1563 			exit(2);
1564 		}
1565 		return (lock.l_pid);
1566 	}
1567 	hold_daemon_lock = 1;
1568 
1569 	return (getpid());
1570 }
1571 
1572 /*
1573  * exit_daemon_lock - release the daemon file lock
1574  */
1575 static void
1576 exit_daemon_lock(void)
1577 {
1578 	struct flock lock;
1579 
1580 	lock.l_type = F_UNLCK;
1581 	lock.l_whence = SEEK_SET;
1582 	lock.l_start = 0;
1583 	lock.l_len = 0;
1584 
1585 	if (fcntl(daemon_lock_fd, F_SETLK, &lock) == -1) {
1586 		syseventd_err_print(INIT_UNLOCK_ERR,
1587 		    local_lock_file, strerror(errno));
1588 	}
1589 
1590 	if (close(daemon_lock_fd) == -1) {
1591 		syseventd_err_print(INIT_LOCK_CLOSE_ERR,
1592 		    local_lock_file, strerror(errno));
1593 		exit(-1);
1594 	}
1595 }
1596 
1597 /*
1598  * syseventd_err_print - print error messages to the terminal if not
1599  *			yet daemonized or to syslog.
1600  */
1601 /*PRINTFLIKE1*/
1602 void
1603 syseventd_err_print(char *message, ...)
1604 {
1605 	va_list ap;
1606 
1607 	(void) mutex_lock(&err_mutex);
1608 	va_start(ap, message);
1609 
1610 	if (logflag) {
1611 		(void) vsyslog(LOG_ERR, message, ap);
1612 	} else {
1613 		(void) fprintf(stderr, "%s: ", prog);
1614 		(void) vfprintf(stderr, message, ap);
1615 	}
1616 	va_end(ap);
1617 	(void) mutex_unlock(&err_mutex);
1618 }
1619 
1620 /*
1621  * syseventd_print -  print messages to the terminal or to syslog
1622  *			the following levels are implemented:
1623  *
1624  * 1 - transient errors that does not affect normal program flow
1625  * 2 - upcall/dispatch interaction
1626  * 3 - program flow trace as each message goes through the daemon
1627  * 8 - all the nit-gritty details of startup and shutdown
1628  * 9 - very verbose event flow tracing (no daemonization of syseventd)
1629  *
1630  */
1631 /*PRINTFLIKE2*/
1632 void
1633 syseventd_print(int level, char *message, ...)
1634 {
1635 	va_list ap;
1636 	static int newline = 1;
1637 
1638 	if (level > debug_level) {
1639 		return;
1640 	}
1641 
1642 	(void) mutex_lock(&err_mutex);
1643 	va_start(ap, message);
1644 	if (logflag) {
1645 		(void) syslog(LOG_DEBUG, "%s[%ld]: ",
1646 		    prog, getpid());
1647 		(void) vsyslog(LOG_DEBUG, message, ap);
1648 	} else {
1649 		if (newline) {
1650 			(void) fprintf(stdout, "%s[%ld]: ",
1651 			    prog, getpid());
1652 			(void) vfprintf(stdout, message, ap);
1653 		} else {
1654 			(void) vfprintf(stdout, message, ap);
1655 		}
1656 	}
1657 	if (message[strlen(message)-1] == '\n') {
1658 		newline = 1;
1659 	} else {
1660 		newline = 0;
1661 	}
1662 	va_end(ap);
1663 	(void) mutex_unlock(&err_mutex);
1664 }
1665