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sysmon_wdog.c revision 1.1.2.3 
      1 /*	$NetBSD: sysmon_wdog.c,v 1.1.2.3 2001/02/11 19:16:20 bouyer Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2000 Zembu Labs, Inc.
      5  * All rights reserved.
      6  *
      7  * Author: Jason R. Thorpe <thorpej (at) zembu.com>
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed by Zembu Labs, Inc.
     20  * 4. Neither the name of Zembu Labs nor the names of its employees may
     21  *    be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY ZEMBU LABS, INC. ``AS IS'' AND ANY EXPRESS
     25  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAR-
     26  * RANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DIS-
     27  * CLAIMED.  IN NO EVENT SHALL ZEMBU LABS BE LIABLE FOR ANY DIRECT, INDIRECT,
     28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     33  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 /*
     37  * Watchdog timer framework for sysmon.  Hardware (and software)
     38  * watchdog timers can register themselves here to provide a
     39  * watchdog function, which provides an abstract interface to the
     40  * user.
     41  */
     42 
     43 #include <sys/param.h>
     44 #include <sys/conf.h>
     45 #include <sys/errno.h>
     46 #include <sys/fcntl.h>
     47 #include <sys/lock.h>
     48 #include <sys/callout.h>
     49 #include <sys/kernel.h>
     50 #include <sys/systm.h>
     51 #include <sys/proc.h>
     52 
     53 #include <dev/sysmon/sysmonvar.h>
     54 
     55 LIST_HEAD(, sysmon_wdog) sysmon_wdog_list =
     56     LIST_HEAD_INITIALIZER(&sysmon_wdog_list);
     57 int sysmon_wdog_count;
     58 struct simplelock sysmon_wdog_list_slock = SIMPLELOCK_INITIALIZER;
     59 
     60 struct simplelock sysmon_wdog_slock = SIMPLELOCK_INITIALIZER;
     61 struct sysmon_wdog *sysmon_armed_wdog;
     62 struct callout sysmon_wdog_callout = CALLOUT_INITIALIZER;
     63 void *sysmon_wdog_sdhook;
     64 
     65 #define	SYSMON_WDOG_LOCK(s)						\
     66 do {									\
     67 	s = splsoftclock();						\
     68 	simple_lock(&sysmon_wdog_slock);				\
     69 } while (0)
     70 
     71 #define	SYSMON_WDOG_UNLOCK(s)						\
     72 do {									\
     73 	simple_unlock(&sysmon_wdog_slock);				\
     74 	splx(s);							\
     75 } while (0)
     76 
     77 struct sysmon_wdog *sysmon_wdog_find(const char *);
     78 void	sysmon_wdog_release(struct sysmon_wdog *);
     79 int	sysmon_wdog_setmode(struct sysmon_wdog *, int, u_int);
     80 void	sysmon_wdog_ktickle(void *);
     81 void	sysmon_wdog_shutdown(void *);
     82 
     83 #define	SYSMON_MINOR_ENVSYS	0
     84 #define	SYSMON_MINOR_WDOG	1
     85 
     86 /*
     87  * sysmonopen_wdog:
     88  *
     89  *	Open the system monitor device.
     90  */
     91 int
     92 sysmonopen_wdog(dev_t dev, int flag, int mode, struct proc *p)
     93 {
     94 
     95 	simple_lock(&sysmon_wdog_list_slock);
     96 	if (sysmon_wdog_sdhook == NULL) {
     97 		sysmon_wdog_sdhook =
     98 		    shutdownhook_establish(sysmon_wdog_shutdown, NULL);
     99 		if (sysmon_wdog_sdhook == NULL)
    100 			printf("WARNING: unable to register watchdog "
    101 			    "shutdown hook\n");
    102 	}
    103 	simple_unlock(&sysmon_wdog_list_slock);
    104 
    105 	return (0);
    106 }
    107 
    108 /*
    109  * sysmonclose_wdog:
    110  *
    111  *	Close the system monitor device.
    112  */
    113 int
    114 sysmonclose_wdog(dev_t dev, int flag, int mode, struct proc *p)
    115 {
    116 	struct sysmon_wdog *smw;
    117 	int omode, s, error;
    118 
    119 	/*
    120 	 * If this is the last close, and there is a watchdog
    121 	 * running in UTICKLE mode, we need to disable it,
    122 	 * otherwise the system will reset in short order.
    123 	 *
    124 	 * XXX Maybe we should just go into KTICKLE mode?
    125 	 */
    126 	SYSMON_WDOG_LOCK(s);
    127 	if ((smw = sysmon_armed_wdog) != NULL) {
    128 		if ((omode = smw->smw_mode) == WDOG_MODE_UTICKLE) {
    129 			error = sysmon_wdog_setmode(smw,
    130 			    WDOG_MODE_DISARMED, smw->smw_period);
    131 			if (error) {
    132 				printf("WARNING: UNABLE TO DISARM "
    133 				    "WATCHDOG %s ON CLOSE!\n",
    134 				    smw->smw_name);
    135 				/*
    136 				 * ...we will probably reboot soon.
    137 				 */
    138 			}
    139 		}
    140 	}
    141 	SYSMON_WDOG_UNLOCK(s);
    142 
    143 	return (error);
    144 }
    145 
    146 /*
    147  * sysmonioctl_wdog:
    148  *
    149  *	Perform a watchdog control request.
    150  */
    151 int
    152 sysmonioctl_wdog(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
    153 {
    154 	struct sysmon_wdog *smw;
    155 	int s, error = 0;
    156 
    157 	switch (cmd) {
    158 	case WDOGIOC_GMODE:
    159 	    {
    160 		struct wdog_mode *wm = (void *) data;
    161 
    162 		wm->wm_name[sizeof(wm->wm_name) - 1] = '\0';
    163 		smw = sysmon_wdog_find(wm->wm_name);
    164 		if (smw == NULL) {
    165 			error = ESRCH;
    166 			break;
    167 		}
    168 
    169 		wm->wm_mode = smw->smw_mode;
    170 		wm->wm_period = smw->smw_period;
    171 		sysmon_wdog_release(smw);
    172 		break;
    173 	    }
    174 
    175 	case WDOGIOC_SMODE:
    176 	    {
    177 		struct wdog_mode *wm = (void *) data;
    178 
    179 		if ((flag & FWRITE) == 0) {
    180 			error = EPERM;
    181 			break;
    182 		}
    183 
    184 		wm->wm_name[sizeof(wm->wm_name) - 1] = '\0';
    185 		smw = sysmon_wdog_find(wm->wm_name);
    186 		if (smw == NULL) {
    187 			error = ESRCH;
    188 			break;
    189 		}
    190 
    191 		if (wm->wm_mode & ~(WDOG_MODE_MASK|WDOG_FEATURE_MASK))
    192 			error = EINVAL;
    193 		else {
    194 			SYSMON_WDOG_LOCK(s);
    195 			error = sysmon_wdog_setmode(smw, wm->wm_mode,
    196 			    wm->wm_period);
    197 			SYSMON_WDOG_UNLOCK(s);
    198 		}
    199 
    200 		sysmon_wdog_release(smw);
    201 		break;
    202 	    }
    203 
    204 	case WDOGIOC_WHICH:
    205 	    {
    206 		struct wdog_mode *wm = (void *) data;
    207 
    208 		SYSMON_WDOG_LOCK(s);
    209 		if ((smw = sysmon_armed_wdog) != NULL) {
    210 			strcpy(wm->wm_name, smw->smw_name);
    211 			wm->wm_mode = smw->smw_mode;
    212 			wm->wm_period = smw->smw_period;
    213 		} else
    214 			error = ESRCH;
    215 		SYSMON_WDOG_UNLOCK(s);
    216 		break;
    217 	    }
    218 
    219 	case WDOGIOC_TICKLE:
    220 		if ((flag & FWRITE) == 0) {
    221 			error = EPERM;
    222 			break;
    223 		}
    224 
    225 		SYSMON_WDOG_LOCK(s);
    226 		if ((smw = sysmon_armed_wdog) != NULL) {
    227 			error = (*smw->smw_tickle)(smw);
    228 			if (error == 0)
    229 				smw->smw_tickler = p->p_pid;
    230 		} else
    231 			error = ESRCH;
    232 		SYSMON_WDOG_UNLOCK(s);
    233 		break;
    234 
    235 	case WDOGIOC_GTICKLER:
    236 		*(pid_t *)data = smw->smw_tickler;
    237 		break;
    238 
    239 	case WDOGIOC_GWDOGS:
    240 	    {
    241 		struct wdog_conf *wc = (void *) data;
    242 		char *cp;
    243 		int i;
    244 
    245 		simple_lock(&sysmon_wdog_list_slock);
    246 		if (wc->wc_names == NULL)
    247 			wc->wc_count = sysmon_wdog_count;
    248 		else {
    249 			for (i = 0, cp = wc->wc_names,
    250 			       smw = LIST_FIRST(&sysmon_wdog_list);
    251 			     i < sysmon_wdog_count && smw != NULL && error == 0;
    252 			     i++, cp += WDOG_NAMESIZE,
    253 			       smw = LIST_NEXT(smw, smw_list))
    254 				error = copyout(smw->smw_name, cp,
    255 				    strlen(smw->smw_name) + 1);
    256 			wc->wc_count = i;
    257 		}
    258 		simple_unlock(&sysmon_wdog_list_slock);
    259 		break;
    260 	    }
    261 
    262 	default:
    263 		error = ENOTTY;
    264 	}
    265 
    266 	return (error);
    267 }
    268 
    269 /*
    270  * sysmon_wdog_register:
    271  *
    272  *	Register a watchdog device.
    273  */
    274 int
    275 sysmon_wdog_register(struct sysmon_wdog *smw)
    276 {
    277 	struct sysmon_wdog *lsmw;
    278 	int error = 0;
    279 
    280 	simple_lock(&sysmon_wdog_list_slock);
    281 
    282 	for (lsmw = LIST_FIRST(&sysmon_wdog_list); lsmw != NULL;
    283 	     lsmw = LIST_NEXT(lsmw, smw_list)) {
    284 		if (strcmp(lsmw->smw_name, smw->smw_name) == 0) {
    285 			error = EEXIST;
    286 			goto out;
    287 		}
    288 	}
    289 
    290 	smw->smw_mode = WDOG_MODE_DISARMED;
    291 	smw->smw_tickler = (pid_t) -1;
    292 	smw->smw_refcnt = 0;
    293 	sysmon_wdog_count++;
    294 	LIST_INSERT_HEAD(&sysmon_wdog_list, smw, smw_list);
    295 
    296  out:
    297 	simple_unlock(&sysmon_wdog_list_slock);
    298 	return (error);
    299 }
    300 
    301 /*
    302  * sysmon_wdog_unregister:
    303  *
    304  *	Unregister a watchdog device.
    305  */
    306 void
    307 sysmon_wdog_unregister(struct sysmon_wdog *smw)
    308 {
    309 
    310 	simple_lock(&sysmon_wdog_list_slock);
    311 	sysmon_wdog_count--;
    312 	LIST_REMOVE(smw, smw_list);
    313 	simple_unlock(&sysmon_wdog_list_slock);
    314 }
    315 
    316 /*
    317  * sysmon_wdog_find:
    318  *
    319  *	Find a watchdog device.  We increase the reference
    320  *	count on a match.
    321  */
    322 struct sysmon_wdog *
    323 sysmon_wdog_find(const char *name)
    324 {
    325 	struct sysmon_wdog *smw;
    326 
    327 	simple_lock(&sysmon_wdog_list_slock);
    328 
    329 	for (smw = LIST_FIRST(&sysmon_wdog_list); smw != NULL;
    330 	     smw = LIST_NEXT(smw, smw_list)) {
    331 		if (strcmp(smw->smw_name, name) == 0)
    332 			break;
    333 	}
    334 
    335 	if (smw != NULL)
    336 		smw->smw_refcnt++;
    337 
    338 	simple_unlock(&sysmon_wdog_list_slock);
    339 	return (smw);
    340 }
    341 
    342 /*
    343  * sysmon_wdog_release:
    344  *
    345  *	Release a watchdog device.
    346  */
    347 void
    348 sysmon_wdog_release(struct sysmon_wdog *smw)
    349 {
    350 
    351 	simple_lock(&sysmon_wdog_list_slock);
    352 	KASSERT(smw->smw_refcnt != 0);
    353 	smw->smw_refcnt--;
    354 	simple_unlock(&sysmon_wdog_list_slock);
    355 }
    356 
    357 /*
    358  * sysmon_wdog_setmode:
    359  *
    360  *	Set the mode of a watchdog device.
    361  */
    362 int
    363 sysmon_wdog_setmode(struct sysmon_wdog *smw, int mode, u_int period)
    364 {
    365 	u_int operiod = smw->smw_period;
    366 	int omode = smw->smw_mode;
    367 	int error = 0;
    368 
    369 	smw->smw_period = period;
    370 	smw->smw_mode = mode;
    371 
    372 	switch (mode & WDOG_MODE_MASK) {
    373 	case WDOG_MODE_DISARMED:
    374 		if (smw != sysmon_armed_wdog) {
    375 			error = EINVAL;
    376 			goto out;
    377 		}
    378 		break;
    379 
    380 	case WDOG_MODE_KTICKLE:
    381 	case WDOG_MODE_UTICKLE:
    382 		if (sysmon_armed_wdog != NULL) {
    383 			error = EBUSY;
    384 			goto out;
    385 		}
    386 		break;
    387 
    388 	default:
    389 		error = EINVAL;
    390 		goto out;
    391 	}
    392 
    393 	error = (*smw->smw_setmode)(smw);
    394 
    395  out:
    396 	if (error) {
    397 		smw->smw_period = operiod;
    398 		smw->smw_mode = omode;
    399 	} else {
    400 		if ((mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
    401 			sysmon_armed_wdog = NULL;
    402 			smw->smw_tickler = (pid_t) -1;
    403 			smw->smw_refcnt--;
    404 			if ((omode & WDOG_MODE_MASK) == WDOG_MODE_KTICKLE)
    405 				callout_stop(&sysmon_wdog_callout);
    406 		} else {
    407 			sysmon_armed_wdog = smw;
    408 			smw->smw_refcnt++;
    409 			if ((mode & WDOG_MODE_MASK) == WDOG_MODE_KTICKLE) {
    410 				callout_reset(&sysmon_wdog_callout,
    411 				    WDOG_PERIOD_TO_TICKS(smw->smw_period) / 2,
    412 				    sysmon_wdog_ktickle, NULL);
    413 			}
    414 		}
    415 	}
    416 	return (error);
    417 }
    418 
    419 /*
    420  * sysmon_wdog_ktickle:
    421  *
    422  *	Kernel watchdog tickle routine.
    423  */
    424 void
    425 sysmon_wdog_ktickle(void *arg)
    426 {
    427 	struct sysmon_wdog *smw;
    428 	int s;
    429 
    430 	SYSMON_WDOG_LOCK(s);
    431 	if ((smw = sysmon_armed_wdog) != NULL) {
    432 		if ((*smw->smw_tickle)(smw) != 0) {
    433 			printf("WARNING: KERNEL TICKLE OF WATCHDOG %s "
    434 			    "FAILED!\n", smw->smw_name);
    435 			/*
    436 			 * ...we will probably reboot soon.
    437 			 */
    438 		}
    439 		callout_reset(&sysmon_wdog_callout,
    440 		    WDOG_PERIOD_TO_TICKS(smw->smw_period) / 2,
    441 		    sysmon_wdog_ktickle, NULL);
    442 	}
    443 	SYSMON_WDOG_UNLOCK(s);
    444 }
    445 
    446 /*
    447  * sysmon_wdog_shutdown:
    448  *
    449  *	Perform shutdown-time operations.
    450  */
    451 void
    452 sysmon_wdog_shutdown(void *arg)
    453 {
    454 	struct sysmon_wdog *smw;
    455 
    456 	/*
    457 	 * XXX Locking here?  I don't think it's necessary.
    458 	 */
    459 
    460 	if ((smw = sysmon_armed_wdog) != NULL) {
    461 		if (sysmon_wdog_setmode(smw, WDOG_MODE_DISARMED,
    462 		    smw->smw_period))
    463 			printf("WARNING: FAILED TO SHUTDOWN WATCHDOG %s!\n",
    464 			    smw->smw_name);
    465 	}
    466 }
    467