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subr_devsw.c revision 1.8 
      1 /*	$NetBSD: subr_devsw.c,v 1.8 2005/12/11 12:24:30 christos Exp $	*/
      2 /*-
      3  * Copyright (c) 2001,2002 The NetBSD Foundation, Inc.
      4  * All rights reserved.
      5  *
      6  * This code is derived from software contributed to The NetBSD Foundation
      7  * by MAEKAWA Masahide <gehenna (at) NetBSD.org>.
      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 the NetBSD
     20  *	Foundation, Inc. and its contributors.
     21  * 4. Neither the name of The NetBSD Foundation nor the names of its
     22  *    contributors may be used to endorse or promote products derived
     23  *    from this software without specific prior written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 #include <sys/cdefs.h>
     39 __KERNEL_RCSID(0, "$NetBSD: subr_devsw.c,v 1.8 2005/12/11 12:24:30 christos Exp $");
     40 
     41 /*
     42  * New device switch framework is developing.
     43  * So debug options are always turned on.
     44  */
     45 #ifndef DEVSW_DEBUG
     46 #define	DEVSW_DEBUG
     47 #endif /* DEVSW_DEBUG */
     48 
     49 #include <sys/param.h>
     50 #include <sys/conf.h>
     51 #include <sys/malloc.h>
     52 #include <sys/systm.h>
     53 
     54 #ifdef DEVSW_DEBUG
     55 #define	DPRINTF(x)	printf x
     56 #else /* DEVSW_DEBUG */
     57 #define	DPRINTF(x)
     58 #endif /* DEVSW_DEBUG */
     59 
     60 #define	MAXDEVSW	4096	/* the maximum of major device number */
     61 #define	BDEVSW_SIZE	(sizeof(struct bdevsw *))
     62 #define	CDEVSW_SIZE	(sizeof(struct cdevsw *))
     63 #define	DEVSWCONV_SIZE	(sizeof(struct devsw_conv))
     64 
     65 extern const struct bdevsw **bdevsw, *bdevsw0[];
     66 extern const struct cdevsw **cdevsw, *cdevsw0[];
     67 extern struct devsw_conv *devsw_conv, devsw_conv0[];
     68 extern const int sys_bdevsws, sys_cdevsws;
     69 extern int max_bdevsws, max_cdevsws, max_devsw_convs;
     70 
     71 static int bdevsw_attach(const char *, const struct bdevsw *, int *);
     72 static int cdevsw_attach(const char *, const struct cdevsw *, int *);
     73 
     74 int
     75 devsw_attach(const char *devname, const struct bdevsw *bdev, int *bmajor,
     76 	     const struct cdevsw *cdev, int *cmajor)
     77 {
     78 	struct devsw_conv *conv;
     79 	char *name;
     80 	int error, i;
     81 
     82 	if (devname == NULL || cdev == NULL)
     83 		return (EINVAL);
     84 
     85 	for (i = 0 ; i < max_devsw_convs ; i++) {
     86 		conv = &devsw_conv[i];
     87 		if (conv->d_name == NULL || strcmp(devname, conv->d_name) != 0)
     88 			continue;
     89 
     90 		if (*bmajor < 0)
     91 			*bmajor = conv->d_bmajor;
     92 		if (*cmajor < 0)
     93 			*cmajor = conv->d_cmajor;
     94 
     95 		if (*bmajor != conv->d_bmajor || *cmajor != conv->d_cmajor)
     96 			return (EINVAL);
     97 		if ((*bmajor >= 0 && bdev == NULL) || *cmajor < 0)
     98 			return (EINVAL);
     99 
    100 		if ((*bmajor >= 0 && bdevsw[*bmajor] != NULL) ||
    101 		    cdevsw[*cmajor] != NULL)
    102 			return (EEXIST);
    103 
    104 		if (bdev != NULL)
    105 			bdevsw[*bmajor] = bdev;
    106 		cdevsw[*cmajor] = cdev;
    107 
    108 		return (0);
    109 	}
    110 
    111 	error = bdevsw_attach(devname, bdev, bmajor);
    112 	if (error != 0)
    113 		return (error);
    114 	error = cdevsw_attach(devname, cdev, cmajor);
    115 	if (error != 0) {
    116 		devsw_detach(bdev, NULL);
    117 		return (error);
    118 	}
    119 
    120 	for (i = 0 ; i < max_devsw_convs ; i++) {
    121 		if (devsw_conv[i].d_name == NULL)
    122 			break;
    123 	}
    124 	if (i == max_devsw_convs) {
    125 		struct devsw_conv *newptr;
    126 		int old, new;
    127 
    128 		old = max_devsw_convs;
    129 		new = old + 1;
    130 
    131 		newptr = malloc(new * DEVSWCONV_SIZE, M_DEVBUF, M_NOWAIT);
    132 		if (newptr == NULL) {
    133 			devsw_detach(bdev, cdev);
    134 			return (ENOMEM);
    135 		}
    136 		newptr[old].d_name = NULL;
    137 		newptr[old].d_bmajor = -1;
    138 		newptr[old].d_cmajor = -1;
    139 		memcpy(newptr, devsw_conv, old * DEVSWCONV_SIZE);
    140 		if (devsw_conv != devsw_conv0)
    141 			free(devsw_conv, M_DEVBUF);
    142 		devsw_conv = newptr;
    143 		max_devsw_convs = new;
    144 	}
    145 
    146 	i = strlen(devname) + 1;
    147 	name = malloc(i, M_DEVBUF, M_NOWAIT);
    148 	if (name == NULL) {
    149 		devsw_detach(bdev, cdev);
    150 		return (ENOMEM);
    151 	}
    152 	strlcpy(name, devname, i);
    153 
    154 	devsw_conv[i].d_name = name;
    155 	devsw_conv[i].d_bmajor = *bmajor;
    156 	devsw_conv[i].d_cmajor = *cmajor;
    157 
    158 	return (0);
    159 }
    160 
    161 static int
    162 bdevsw_attach(const char *devname, const struct bdevsw *devsw, int *devmajor)
    163 {
    164 	int bmajor, i;
    165 
    166 	if (devsw == NULL)
    167 		return (0);
    168 
    169 	if (*devmajor < 0) {
    170 		for (bmajor = sys_bdevsws ; bmajor < max_bdevsws ; bmajor++) {
    171 			if (bdevsw[bmajor] != NULL)
    172 				continue;
    173 			for (i = 0 ; i < max_devsw_convs ; i++) {
    174 				if (devsw_conv[i].d_bmajor == bmajor)
    175 					break;
    176 			}
    177 			if (i != max_devsw_convs)
    178 				continue;
    179 			break;
    180 		}
    181 		*devmajor = bmajor;
    182 	}
    183 	if (*devmajor >= MAXDEVSW) {
    184 #ifdef DEVSW_DEBUG
    185 		panic("bdevsw_attach: block majors exhausted");
    186 #endif /* DEVSW_DEBUG */
    187 		return (ENOMEM);
    188 	}
    189 
    190 	if (*devmajor >= max_bdevsws) {
    191 		const struct bdevsw **newptr;
    192 		int old, new;
    193 
    194 		old = max_bdevsws;
    195 		new = *devmajor + 1;
    196 
    197 		newptr = malloc(new * BDEVSW_SIZE, M_DEVBUF, M_NOWAIT);
    198 		if (newptr == NULL)
    199 			return (ENOMEM);
    200 		memset(newptr + old, 0, (new - old) * BDEVSW_SIZE);
    201 		if (old != 0) {
    202 			memcpy(newptr, bdevsw, old * BDEVSW_SIZE);
    203 			if (bdevsw != bdevsw0)
    204 				free(bdevsw, M_DEVBUF);
    205 		}
    206 		bdevsw = newptr;
    207 		max_bdevsws = new;
    208 	}
    209 
    210 	if (bdevsw[*devmajor] != NULL)
    211 		return (EEXIST);
    212 
    213 	bdevsw[*devmajor] = devsw;
    214 
    215 	return (0);
    216 }
    217 
    218 static int
    219 cdevsw_attach(const char *devname, const struct cdevsw *devsw, int *devmajor)
    220 {
    221 	int cmajor, i;
    222 
    223 	if (*devmajor < 0) {
    224 		for (cmajor = sys_cdevsws ; cmajor < max_cdevsws ; cmajor++) {
    225 			if (cdevsw[cmajor] != NULL)
    226 				continue;
    227 			for (i = 0 ; i < max_devsw_convs ; i++) {
    228 				if (devsw_conv[i].d_cmajor == cmajor)
    229 					break;
    230 			}
    231 			if (i != max_devsw_convs)
    232 				continue;
    233 			break;
    234 		}
    235 		*devmajor = cmajor;
    236 	}
    237 	if (*devmajor >= MAXDEVSW) {
    238 #ifdef DEVSW_DEBUG
    239 		panic("cdevsw_attach: character majors exhausted");
    240 #endif /* DEVSW_DEBUG */
    241 		return (ENOMEM);
    242 	}
    243 
    244 	if (*devmajor >= max_cdevsws) {
    245 		const struct cdevsw **newptr;
    246 		int old, new;
    247 
    248 		old = max_cdevsws;
    249 		new = *devmajor + 1;
    250 
    251 		newptr = malloc(new * CDEVSW_SIZE, M_DEVBUF, M_NOWAIT);
    252 		if (newptr == NULL)
    253 			return (ENOMEM);
    254 		memset(newptr + old, 0, (new - old) * CDEVSW_SIZE);
    255 		if (old != 0) {
    256 			memcpy(newptr, cdevsw, old * CDEVSW_SIZE);
    257 			if (cdevsw != cdevsw0)
    258 				free(cdevsw, M_DEVBUF);
    259 		}
    260 		cdevsw = newptr;
    261 		max_cdevsws = new;
    262 	}
    263 
    264 	if (cdevsw[*devmajor] != NULL)
    265 		return (EEXIST);
    266 
    267 	cdevsw[*devmajor] = devsw;
    268 
    269 	return (0);
    270 }
    271 
    272 void
    273 devsw_detach(const struct bdevsw *bdev, const struct cdevsw *cdev)
    274 {
    275 	int i;
    276 
    277 	if (bdev != NULL) {
    278 		for (i = 0 ; i < max_bdevsws ; i++) {
    279 			if (bdevsw[i] != bdev)
    280 				continue;
    281 			bdevsw[i] = NULL;
    282 			break;
    283 		}
    284 	}
    285 	if (cdev != NULL) {
    286 		for (i = 0 ; i < max_cdevsws ; i++) {
    287 			if (cdevsw[i] != cdev)
    288 				continue;
    289 			cdevsw[i] = NULL;
    290 			break;
    291 		}
    292 	}
    293 }
    294 
    295 const struct bdevsw *
    296 bdevsw_lookup(dev_t dev)
    297 {
    298 	int bmajor;
    299 
    300 	if (dev == NODEV)
    301 		return (NULL);
    302 	bmajor = major(dev);
    303 	if (bmajor < 0 || bmajor >= max_bdevsws)
    304 		return (NULL);
    305 
    306 	return (bdevsw[bmajor]);
    307 }
    308 
    309 const struct cdevsw *
    310 cdevsw_lookup(dev_t dev)
    311 {
    312 	int cmajor;
    313 
    314 	if (dev == NODEV)
    315 		return (NULL);
    316 	cmajor = major(dev);
    317 	if (cmajor < 0 || cmajor >= max_cdevsws)
    318 		return (NULL);
    319 
    320 	return (cdevsw[cmajor]);
    321 }
    322 
    323 int
    324 bdevsw_lookup_major(const struct bdevsw *bdev)
    325 {
    326 	int bmajor;
    327 
    328 	for (bmajor = 0 ; bmajor < max_bdevsws ; bmajor++) {
    329 		if (bdevsw[bmajor] == bdev)
    330 			return (bmajor);
    331 	}
    332 
    333 	return (-1);
    334 }
    335 
    336 int
    337 cdevsw_lookup_major(const struct cdevsw *cdev)
    338 {
    339 	int cmajor;
    340 
    341 	for (cmajor = 0 ; cmajor < max_cdevsws ; cmajor++) {
    342 		if (cdevsw[cmajor] == cdev)
    343 			return (cmajor);
    344 	}
    345 
    346 	return (-1);
    347 }
    348 
    349 /*
    350  * Convert from block major number to name.
    351  */
    352 const char *
    353 devsw_blk2name(int bmajor)
    354 {
    355 	int cmajor, i;
    356 
    357 	if (bmajor < 0 || bmajor >= max_bdevsws || bdevsw[bmajor] == NULL)
    358 		return (NULL);
    359 
    360 	for (i = 0 ; i < max_devsw_convs ; i++) {
    361 		if (devsw_conv[i].d_bmajor != bmajor)
    362 			continue;
    363 		cmajor = devsw_conv[i].d_cmajor;
    364 		if (cmajor < 0 || cmajor >= max_cdevsws ||
    365 		    cdevsw[cmajor] == NULL)
    366 			return (NULL);
    367 		return (devsw_conv[i].d_name);
    368 	}
    369 
    370 	return (NULL);
    371 }
    372 
    373 /*
    374  * Convert from device name to block major number.
    375  */
    376 int
    377 devsw_name2blk(const char *name, char *devname, size_t devnamelen)
    378 {
    379 	struct devsw_conv *conv;
    380 	int bmajor, i;
    381 
    382 	if (name == NULL)
    383 		return (-1);
    384 
    385 	for (i = 0 ; i < max_devsw_convs ; i++) {
    386 		size_t len;
    387 
    388 		conv = &devsw_conv[i];
    389 		if (conv->d_name == NULL)
    390 			continue;
    391 		len = strlen(conv->d_name);
    392 		if (strncmp(conv->d_name, name, len) != 0)
    393 			continue;
    394 		if (*(name +len) && !isdigit(*(name + len)))
    395 			continue;
    396 		bmajor = conv->d_bmajor;
    397 		if (bmajor < 0 || bmajor >= max_bdevsws ||
    398 		    bdevsw[bmajor] == NULL)
    399 			break;
    400 		if (devname != NULL) {
    401 #ifdef DEVSW_DEBUG
    402 			if (strlen(conv->d_name) >= devnamelen)
    403 				printf("devsw_name2blk: too short buffer");
    404 #endif /* DEVSW_DEBUG */
    405 			strncpy(devname, conv->d_name, devnamelen);
    406 			devname[devnamelen - 1] = '\0';
    407 		}
    408 		return (bmajor);
    409 	}
    410 
    411 	return (-1);
    412 }
    413 
    414 /*
    415  * Convert from character dev_t to block dev_t.
    416  */
    417 dev_t
    418 devsw_chr2blk(dev_t cdev)
    419 {
    420 	int bmajor, cmajor, i;
    421 
    422 	if (cdevsw_lookup(cdev) == NULL)
    423 		return (NODEV);
    424 
    425 	cmajor = major(cdev);
    426 
    427 	for (i = 0 ; i < max_devsw_convs ; i++) {
    428 		if (devsw_conv[i].d_cmajor != cmajor)
    429 			continue;
    430 		bmajor = devsw_conv[i].d_bmajor;
    431 		if (bmajor < 0 || bmajor >= max_bdevsws ||
    432 		    bdevsw[bmajor] == NULL)
    433 			return (NODEV);
    434 		return (makedev(bmajor, minor(cdev)));
    435 	}
    436 
    437 	return (NODEV);
    438 }
    439 
    440 /*
    441  * Convert from block dev_t to character dev_t.
    442  */
    443 dev_t
    444 devsw_blk2chr(dev_t bdev)
    445 {
    446 	int bmajor, cmajor, i;
    447 
    448 	if (bdevsw_lookup(bdev) == NULL)
    449 		return (NODEV);
    450 
    451 	bmajor = major(bdev);
    452 
    453 	for (i = 0 ; i < max_devsw_convs ; i++) {
    454 		if (devsw_conv[i].d_bmajor != bmajor)
    455 			continue;
    456 		cmajor = devsw_conv[i].d_cmajor;
    457 		if (cmajor < 0 || cmajor >= max_cdevsws ||
    458 		    cdevsw[cmajor] == NULL)
    459 			return (NODEV);
    460 		return (makedev(cmajor, minor(bdev)));
    461 	}
    462 
    463 	return (NODEV);
    464 }
    465