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kern_drvctl.c revision 1.45 
      1 /* $NetBSD: kern_drvctl.c,v 1.45 2020/06/11 02:28:01 thorpej Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2004
      5  * 	Matthias Drochner.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions, and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: kern_drvctl.c,v 1.45 2020/06/11 02:28:01 thorpej Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/systm.h>
     34 #include <sys/kernel.h>
     35 #include <sys/conf.h>
     36 #include <sys/device.h>
     37 #include <sys/event.h>
     38 #include <sys/kmem.h>
     39 #include <sys/ioctl.h>
     40 #include <sys/fcntl.h>
     41 #include <sys/file.h>
     42 #include <sys/filedesc.h>
     43 #include <sys/select.h>
     44 #include <sys/poll.h>
     45 #include <sys/drvctlio.h>
     46 #include <sys/devmon.h>
     47 #include <sys/stat.h>
     48 #include <sys/kauth.h>
     49 #include <sys/lwp.h>
     50 #include <sys/module.h>
     51 
     52 #include "ioconf.h"
     53 
     54 struct drvctl_event {
     55 	TAILQ_ENTRY(drvctl_event) dce_link;
     56 	prop_dictionary_t	dce_event;
     57 };
     58 
     59 TAILQ_HEAD(drvctl_queue, drvctl_event);
     60 
     61 static struct drvctl_queue	drvctl_eventq;		/* FIFO */
     62 static kcondvar_t		drvctl_cond;
     63 static kmutex_t			drvctl_lock;
     64 static int			drvctl_nopen = 0, drvctl_eventcnt = 0;
     65 static struct selinfo		drvctl_rdsel;
     66 
     67 #define DRVCTL_EVENTQ_DEPTH	64	/* arbitrary queue limit */
     68 
     69 dev_type_open(drvctlopen);
     70 
     71 const struct cdevsw drvctl_cdevsw = {
     72 	.d_open = drvctlopen,
     73 	.d_close = nullclose,
     74 	.d_read = nullread,
     75 	.d_write = nullwrite,
     76 	.d_ioctl = noioctl,
     77 	.d_stop = nostop,
     78 	.d_tty = notty,
     79 	.d_poll = nopoll,
     80 	.d_mmap = nommap,
     81 	.d_kqfilter = nokqfilter,
     82 	.d_discard = nodiscard,
     83 	.d_flag = D_OTHER
     84 };
     85 
     86 static int	drvctl_read(struct file *, off_t *, struct uio *,
     87 			    kauth_cred_t, int);
     88 static int	drvctl_write(struct file *, off_t *, struct uio *,
     89 			     kauth_cred_t, int);
     90 static int	drvctl_ioctl(struct file *, u_long, void *);
     91 static int	drvctl_poll(struct file *, int);
     92 static int	drvctl_stat(struct file *, struct stat *);
     93 static int	drvctl_close(struct file *);
     94 
     95 static const struct fileops drvctl_fileops = {
     96 	.fo_name = "drvctl",
     97 	.fo_read = drvctl_read,
     98 	.fo_write = drvctl_write,
     99 	.fo_ioctl = drvctl_ioctl,
    100 	.fo_fcntl = fnullop_fcntl,
    101 	.fo_poll = drvctl_poll,
    102 	.fo_stat = drvctl_stat,
    103 	.fo_close = drvctl_close,
    104 	.fo_kqfilter = fnullop_kqfilter,
    105 	.fo_restart = fnullop_restart,
    106 };
    107 
    108 #define MAXLOCATORS 100
    109 
    110 static int (*saved_insert_vec)(const char *, prop_dictionary_t) = NULL;
    111 
    112 static int drvctl_command(struct lwp *, struct plistref *, u_long, int);
    113 static int drvctl_getevent(struct lwp *, struct plistref *, u_long, int);
    114 
    115 void
    116 drvctl_init(void)
    117 {
    118 	TAILQ_INIT(&drvctl_eventq);
    119 	mutex_init(&drvctl_lock, MUTEX_DEFAULT, IPL_NONE);
    120 	cv_init(&drvctl_cond, "devmon");
    121 	selinit(&drvctl_rdsel);
    122 }
    123 
    124 void
    125 drvctl_fini(void)
    126 {
    127 
    128 	seldestroy(&drvctl_rdsel);
    129 	cv_destroy(&drvctl_cond);
    130 	mutex_destroy(&drvctl_lock);
    131 }
    132 
    133 int
    134 devmon_insert(const char *event, prop_dictionary_t ev)
    135 {
    136 	struct drvctl_event *dce, *odce;
    137 
    138 	mutex_enter(&drvctl_lock);
    139 
    140 	if (drvctl_nopen == 0) {
    141 		prop_object_release(ev);
    142 		mutex_exit(&drvctl_lock);
    143 		return 0;
    144 	}
    145 
    146 	/* Fill in mandatory member */
    147 	if (!prop_dictionary_set_string_nocopy(ev, "event", event)) {
    148 		prop_object_release(ev);
    149 		mutex_exit(&drvctl_lock);
    150 		return 0;
    151 	}
    152 
    153 	dce = kmem_alloc(sizeof(*dce), KM_SLEEP);
    154 	dce->dce_event = ev;
    155 
    156 	if (drvctl_eventcnt == DRVCTL_EVENTQ_DEPTH) {
    157 		odce = TAILQ_FIRST(&drvctl_eventq);
    158 		TAILQ_REMOVE(&drvctl_eventq, odce, dce_link);
    159 		prop_object_release(odce->dce_event);
    160 		kmem_free(odce, sizeof(*odce));
    161 		--drvctl_eventcnt;
    162 	}
    163 
    164 	TAILQ_INSERT_TAIL(&drvctl_eventq, dce, dce_link);
    165 	++drvctl_eventcnt;
    166 	cv_broadcast(&drvctl_cond);
    167 	selnotify(&drvctl_rdsel, 0, 0);
    168 
    169 	mutex_exit(&drvctl_lock);
    170 	return 0;
    171 }
    172 
    173 int
    174 drvctlopen(dev_t dev, int flags, int mode, struct lwp *l)
    175 {
    176 	struct file *fp;
    177 	int fd;
    178 	int ret;
    179 
    180 	ret = fd_allocfile(&fp, &fd);
    181 	if (ret)
    182 		return ret;
    183 
    184 	/* XXX setup context */
    185 	mutex_enter(&drvctl_lock);
    186 	ret = fd_clone(fp, fd, flags, &drvctl_fileops, /* context */NULL);
    187 	++drvctl_nopen;
    188 	mutex_exit(&drvctl_lock);
    189 
    190 	return ret;
    191 }
    192 
    193 static int
    194 pmdevbyname(u_long cmd, struct devpmargs *a)
    195 {
    196 	device_t d;
    197 
    198 	if ((d = device_find_by_xname(a->devname)) == NULL)
    199 		return ENXIO;
    200 
    201 	switch (cmd) {
    202 	case DRVSUSPENDDEV:
    203 		return pmf_device_recursive_suspend(d, PMF_Q_DRVCTL) ? 0 : EBUSY;
    204 	case DRVRESUMEDEV:
    205 		if (a->flags & DEVPM_F_SUBTREE) {
    206 			return pmf_device_subtree_resume(d, PMF_Q_DRVCTL)
    207 			    ? 0 : EBUSY;
    208 		} else {
    209 			return pmf_device_recursive_resume(d, PMF_Q_DRVCTL)
    210 			    ? 0 : EBUSY;
    211 		}
    212 	default:
    213 		return EPASSTHROUGH;
    214 	}
    215 }
    216 
    217 static int
    218 listdevbyname(struct devlistargs *l)
    219 {
    220 	device_t d, child;
    221 	deviter_t di;
    222 	int cnt = 0, idx, error = 0;
    223 
    224 	if (*l->l_devname == '\0')
    225 		d = NULL;
    226 	else if (memchr(l->l_devname, 0, sizeof(l->l_devname)) == NULL)
    227 		return EINVAL;
    228 	else if ((d = device_find_by_xname(l->l_devname)) == NULL)
    229 		return ENXIO;
    230 
    231 	for (child = deviter_first(&di, 0); child != NULL;
    232 	     child = deviter_next(&di)) {
    233 		if (device_parent(child) != d)
    234 			continue;
    235 		idx = cnt++;
    236 		if (l->l_childname == NULL || idx >= l->l_children)
    237 			continue;
    238 		error = copyoutstr(device_xname(child), l->l_childname[idx],
    239 				sizeof(l->l_childname[idx]), NULL);
    240 		if (error != 0)
    241 			break;
    242 	}
    243 	deviter_release(&di);
    244 
    245 	l->l_children = cnt;
    246 	return error;
    247 }
    248 
    249 static int
    250 detachdevbyname(const char *devname)
    251 {
    252 	device_t d;
    253 
    254 	if ((d = device_find_by_xname(devname)) == NULL)
    255 		return ENXIO;
    256 
    257 #ifndef XXXFULLRISK
    258 	/*
    259 	 * If the parent cannot be notified, it might keep
    260 	 * pointers to the detached device.
    261 	 * There might be a private notification mechanism,
    262 	 * but better play it safe here.
    263 	 */
    264 	if (d->dv_parent && !d->dv_parent->dv_cfattach->ca_childdetached)
    265 		return ENOTSUP;
    266 #endif
    267 	return config_detach(d, 0);
    268 }
    269 
    270 static int
    271 rescanbus(const char *busname, const char *ifattr,
    272 	  int numlocators, const int *locators)
    273 {
    274 	int i, rc;
    275 	device_t d;
    276 	const struct cfiattrdata * const *ap;
    277 
    278 	/* XXX there should be a way to get limits and defaults (per device)
    279 	   from config generated data */
    280 	int locs[MAXLOCATORS];
    281 	for (i = 0; i < MAXLOCATORS; i++)
    282 		locs[i] = -1;
    283 
    284 	for (i = 0; i < numlocators;i++)
    285 		locs[i] = locators[i];
    286 
    287 	if ((d = device_find_by_xname(busname)) == NULL)
    288 		return ENXIO;
    289 
    290 	/*
    291 	 * must support rescan, and must have something
    292 	 * to attach to
    293 	 */
    294 	if (!d->dv_cfattach->ca_rescan ||
    295 	    !d->dv_cfdriver->cd_attrs)
    296 		return ENODEV;
    297 
    298 	/* allow to omit attribute if there is exactly one */
    299 	if (!ifattr) {
    300 		if (d->dv_cfdriver->cd_attrs[1])
    301 			return EINVAL;
    302 		ifattr = d->dv_cfdriver->cd_attrs[0]->ci_name;
    303 	} else {
    304 		/* check for valid attribute passed */
    305 		for (ap = d->dv_cfdriver->cd_attrs; *ap; ap++)
    306 			if (!strcmp((*ap)->ci_name, ifattr))
    307 				break;
    308 		if (!*ap)
    309 			return EINVAL;
    310 	}
    311 
    312 	rc = (*d->dv_cfattach->ca_rescan)(d, ifattr, locs);
    313 	config_deferred(NULL);
    314 	return rc;
    315 }
    316 
    317 static int
    318 drvctl_read(struct file *fp, off_t *offp, struct uio *uio, kauth_cred_t cred,
    319     int flags)
    320 {
    321 	return ENODEV;
    322 }
    323 
    324 static int
    325 drvctl_write(struct file *fp, off_t *offp, struct uio *uio, kauth_cred_t cred,
    326     int flags)
    327 {
    328 	return ENODEV;
    329 }
    330 
    331 static int
    332 drvctl_ioctl(struct file *fp, u_long cmd, void *data)
    333 {
    334 	int res;
    335 	char *ifattr;
    336 	int *locs;
    337 	size_t locs_sz = 0; /* XXXgcc */
    338 
    339 	switch (cmd) {
    340 	case DRVSUSPENDDEV:
    341 	case DRVRESUMEDEV:
    342 #define d ((struct devpmargs *)data)
    343 		res = pmdevbyname(cmd, d);
    344 #undef d
    345 		break;
    346 	case DRVLISTDEV:
    347 		res = listdevbyname((struct devlistargs *)data);
    348 		break;
    349 	case DRVDETACHDEV:
    350 #define d ((struct devdetachargs *)data)
    351 		res = detachdevbyname(d->devname);
    352 #undef d
    353 		break;
    354 	case DRVRESCANBUS:
    355 #define d ((struct devrescanargs *)data)
    356 		d->busname[sizeof(d->busname) - 1] = '\0';
    357 
    358 		/* XXX better copyin? */
    359 		if (d->ifattr[0]) {
    360 			d->ifattr[sizeof(d->ifattr) - 1] = '\0';
    361 			ifattr = d->ifattr;
    362 		} else
    363 			ifattr = 0;
    364 
    365 		if (d->numlocators) {
    366 			if (d->numlocators > MAXLOCATORS)
    367 				return EINVAL;
    368 			locs_sz = d->numlocators * sizeof(int);
    369 			locs = kmem_alloc(locs_sz, KM_SLEEP);
    370 			res = copyin(d->locators, locs, locs_sz);
    371 			if (res) {
    372 				kmem_free(locs, locs_sz);
    373 				return res;
    374 			}
    375 		} else
    376 			locs = NULL;
    377 		res = rescanbus(d->busname, ifattr, d->numlocators, locs);
    378 		if (locs)
    379 			kmem_free(locs, locs_sz);
    380 #undef d
    381 		break;
    382 	case DRVCTLCOMMAND:
    383 	    	res = drvctl_command(curlwp, (struct plistref *)data, cmd,
    384 		    fp->f_flag);
    385 	    	break;
    386 	case DRVGETEVENT:
    387 		res = drvctl_getevent(curlwp, (struct plistref *)data, cmd,
    388 		    fp->f_flag);
    389 		break;
    390 	default:
    391 		return EPASSTHROUGH;
    392 	}
    393 	return res;
    394 }
    395 
    396 static int
    397 drvctl_stat(struct file *fp, struct stat *st)
    398 {
    399 	(void)memset(st, 0, sizeof(*st));
    400 	st->st_uid = kauth_cred_geteuid(fp->f_cred);
    401 	st->st_gid = kauth_cred_getegid(fp->f_cred);
    402 	return 0;
    403 }
    404 
    405 static int
    406 drvctl_poll(struct file *fp, int events)
    407 {
    408 	int revents = 0;
    409 
    410 	if (!TAILQ_EMPTY(&drvctl_eventq))
    411 		revents |= events & (POLLIN | POLLRDNORM);
    412 	else
    413 		selrecord(curlwp, &drvctl_rdsel);
    414 
    415 	return revents;
    416 }
    417 
    418 static int
    419 drvctl_close(struct file *fp)
    420 {
    421 	struct drvctl_event *dce;
    422 
    423 	/* XXX free context */
    424 	mutex_enter(&drvctl_lock);
    425 	KASSERT(drvctl_nopen > 0);
    426 	--drvctl_nopen;
    427 	if (drvctl_nopen == 0) {
    428 		/* flush queue */
    429 		while ((dce = TAILQ_FIRST(&drvctl_eventq)) != NULL) {
    430 			TAILQ_REMOVE(&drvctl_eventq, dce, dce_link);
    431 			KASSERT(drvctl_eventcnt > 0);
    432 			--drvctl_eventcnt;
    433 			prop_object_release(dce->dce_event);
    434 			kmem_free(dce, sizeof(*dce));
    435 		}
    436 	}
    437 	mutex_exit(&drvctl_lock);
    438 
    439 	return 0;
    440 }
    441 
    442 void
    443 drvctlattach(int arg __unused)
    444 {
    445 }
    446 
    447 /*****************************************************************************
    448  * Driver control command processing engine
    449  *****************************************************************************/
    450 
    451 static int
    452 drvctl_command_get_properties(struct lwp *l,
    453 			      prop_dictionary_t command_dict,
    454 			      prop_dictionary_t results_dict)
    455 {
    456 	prop_dictionary_t args_dict;
    457 	prop_string_t devname_string;
    458 	device_t dev;
    459 	deviter_t di;
    460 
    461 	args_dict = prop_dictionary_get(command_dict, "drvctl-arguments");
    462 	if (args_dict == NULL)
    463 		return EINVAL;
    464 
    465 	devname_string = prop_dictionary_get(args_dict, "device-name");
    466 	if (devname_string == NULL)
    467 		return EINVAL;
    468 
    469 	for (dev = deviter_first(&di, 0); dev != NULL;
    470 	     dev = deviter_next(&di)) {
    471 		if (prop_string_equals_string(devname_string,
    472 					       device_xname(dev))) {
    473 			prop_dictionary_set(results_dict, "drvctl-result-data",
    474 			    device_properties(dev));
    475 			break;
    476 		}
    477 	}
    478 
    479 	deviter_release(&di);
    480 
    481 	if (dev == NULL)
    482 		return ESRCH;
    483 
    484 	return 0;
    485 }
    486 
    487 struct drvctl_command_desc {
    488 	const char *dcd_name;		/* command name */
    489 	int (*dcd_func)(struct lwp *,	/* handler function */
    490 			prop_dictionary_t,
    491 			prop_dictionary_t);
    492 	int dcd_rw;			/* read or write required */
    493 };
    494 
    495 static const struct drvctl_command_desc drvctl_command_table[] = {
    496 	{ .dcd_name = "get-properties",
    497 	  .dcd_func = drvctl_command_get_properties,
    498 	  .dcd_rw   = FREAD,
    499 	},
    500 
    501 	{ .dcd_name = NULL }
    502 };
    503 
    504 static int
    505 drvctl_command(struct lwp *l, struct plistref *pref, u_long ioctl_cmd,
    506 	       int fflag)
    507 {
    508 	prop_dictionary_t command_dict, results_dict;
    509 	prop_string_t command_string;
    510 	const struct drvctl_command_desc *dcd;
    511 	int error;
    512 
    513 	error = prop_dictionary_copyin_ioctl(pref, ioctl_cmd, &command_dict);
    514 	if (error)
    515 		return error;
    516 
    517 	results_dict = prop_dictionary_create();
    518 	if (results_dict == NULL) {
    519 		prop_object_release(command_dict);
    520 		return ENOMEM;
    521 	}
    522 
    523 	command_string = prop_dictionary_get(command_dict, "drvctl-command");
    524 	if (command_string == NULL) {
    525 		error = EINVAL;
    526 		goto out;
    527 	}
    528 
    529 	for (dcd = drvctl_command_table; dcd->dcd_name != NULL; dcd++) {
    530 		if (prop_string_equals_string(command_string,
    531 					      dcd->dcd_name))
    532 			break;
    533 	}
    534 
    535 	if (dcd->dcd_name == NULL) {
    536 		error = EINVAL;
    537 		goto out;
    538 	}
    539 
    540 	if ((fflag & dcd->dcd_rw) == 0) {
    541 		error = EPERM;
    542 		goto out;
    543 	}
    544 
    545 	error = (*dcd->dcd_func)(l, command_dict, results_dict);
    546 
    547 	prop_dictionary_set_int32(results_dict, "drvctl-error", error);
    548 
    549 	error = prop_dictionary_copyout_ioctl(pref, ioctl_cmd, results_dict);
    550  out:
    551 	prop_object_release(command_dict);
    552 	prop_object_release(results_dict);
    553 	return error;
    554 }
    555 
    556 static int
    557 drvctl_getevent(struct lwp *l, struct plistref *pref, u_long ioctl_cmd,
    558 	        int fflag)
    559 {
    560 	struct drvctl_event *dce;
    561 	int ret;
    562 
    563 	if ((fflag & (FREAD|FWRITE)) != (FREAD|FWRITE))
    564 		return EPERM;
    565 
    566 	mutex_enter(&drvctl_lock);
    567 	while ((dce = TAILQ_FIRST(&drvctl_eventq)) == NULL) {
    568 		if (fflag & O_NONBLOCK) {
    569 			mutex_exit(&drvctl_lock);
    570 			return EWOULDBLOCK;
    571 		}
    572 
    573 		ret = cv_wait_sig(&drvctl_cond, &drvctl_lock);
    574 		if (ret) {
    575 			mutex_exit(&drvctl_lock);
    576 			return ret;
    577 		}
    578 	}
    579 	TAILQ_REMOVE(&drvctl_eventq, dce, dce_link);
    580 	KASSERT(drvctl_eventcnt > 0);
    581 	--drvctl_eventcnt;
    582 	mutex_exit(&drvctl_lock);
    583 
    584 	ret = prop_dictionary_copyout_ioctl(pref, ioctl_cmd, dce->dce_event);
    585 
    586 	prop_object_release(dce->dce_event);
    587 	kmem_free(dce, sizeof(*dce));
    588 
    589 	return ret;
    590 }
    591 
    592 /*
    593  * Module glue
    594  */
    595 
    596 MODULE(MODULE_CLASS_DRIVER, drvctl, NULL);
    597 
    598 int
    599 drvctl_modcmd(modcmd_t cmd, void *arg)
    600 {
    601 	int error;
    602 #ifdef _MODULE
    603 	int bmajor, cmajor;
    604 #endif
    605 
    606 	error = 0;
    607 	switch (cmd) {
    608 	case MODULE_CMD_INIT:
    609 		drvctl_init();
    610 
    611 		mutex_enter(&drvctl_lock);
    612 #ifdef _MODULE
    613 		bmajor = cmajor = -1;
    614 		error = devsw_attach("drvctl", NULL, &bmajor,
    615 		    &drvctl_cdevsw, &cmajor);
    616 #endif
    617 		if (error == 0) {
    618 			KASSERT(saved_insert_vec == NULL);
    619 			saved_insert_vec = devmon_insert_vec;
    620 			devmon_insert_vec = devmon_insert;
    621 		}
    622 
    623 		mutex_exit(&drvctl_lock);
    624 		break;
    625 
    626 	case MODULE_CMD_FINI:
    627 		mutex_enter(&drvctl_lock);
    628 		if (drvctl_nopen != 0 || drvctl_eventcnt != 0 ) {
    629 			mutex_exit(&drvctl_lock);
    630 			return EBUSY;
    631 		}
    632 		KASSERT(saved_insert_vec != NULL);
    633 		devmon_insert_vec = saved_insert_vec;
    634 		saved_insert_vec = NULL;
    635 #ifdef _MODULE
    636 		error = devsw_detach(NULL, &drvctl_cdevsw);
    637 		if (error != 0) {
    638 			saved_insert_vec = devmon_insert_vec;
    639 			devmon_insert_vec = devmon_insert;
    640 		}
    641 #endif
    642 		mutex_exit(&drvctl_lock);
    643 		if (error == 0)
    644 			drvctl_fini();
    645 
    646 		break;
    647 	default:
    648 		error = ENOTTY;
    649 		break;
    650 	}
    651 
    652 	return error;
    653 }
    654