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subr_devsw.c revision 1.5 
      1 /*	$NetBSD: subr_devsw.c,v 1.5 2003/02/01 11:12:35 mrg 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 /*
     39  * New device switch framework is developing.
     40  * So debug options are always turned on.
     41  */
     42 #ifndef DEVSW_DEBUG
     43 #define	DEVSW_DEBUG
     44 #endif /* DEVSW_DEBUG */
     45 
     46 #include <sys/param.h>
     47 #include <sys/conf.h>
     48 #include <sys/malloc.h>
     49 #include <sys/systm.h>
     50 
     51 #ifdef DEVSW_DEBUG
     52 #define	DPRINTF(x)	printf x
     53 #else /* DEVSW_DEBUG */
     54 #define	DPRINTF(x)
     55 #endif /* DEVSW_DEBUG */
     56 
     57 #define	MAXDEVSW	4096	/* the maximum of major device number */
     58 #define	BDEVSW_SIZE	(sizeof(struct bdevsw *))
     59 #define	CDEVSW_SIZE	(sizeof(struct cdevsw *))
     60 #define	DEVSWCONV_SIZE	(sizeof(struct devsw_conv))
     61 
     62 extern const struct bdevsw **bdevsw, *bdevsw0[];
     63 extern const struct cdevsw **cdevsw, *cdevsw0[];
     64 extern struct devsw_conv *devsw_conv, devsw_conv0[];
     65 extern const int sys_bdevsws, sys_cdevsws;
     66 extern int max_bdevsws, max_cdevsws, max_devsw_convs;
     67 
     68 static int bdevsw_attach(const char *, const struct bdevsw *, int *);
     69 static int cdevsw_attach(const char *, const struct cdevsw *, int *);
     70 
     71 int
     72 devsw_attach(const char *devname, const struct bdevsw *bdev, int *bmajor,
     73 	     const struct cdevsw *cdev, int *cmajor)
     74 {
     75 	struct devsw_conv *conv;
     76 	char *name;
     77 	int error, i;
     78 
     79 	if (devname == NULL || cdev == NULL)
     80 		return (EINVAL);
     81 
     82 	for (i = 0 ; i < max_devsw_convs ; i++) {
     83 		conv = &devsw_conv[i];
     84 		if (conv->d_name == NULL || strcmp(devname, conv->d_name) != 0)
     85 			continue;
     86 
     87 		if (*bmajor < 0)
     88 			*bmajor = conv->d_bmajor;
     89 		if (*cmajor < 0)
     90 			*cmajor = conv->d_cmajor;
     91 
     92 		if (*bmajor != conv->d_bmajor || *cmajor != conv->d_cmajor)
     93 			return (EINVAL);
     94 		if ((*bmajor >= 0 && bdev == NULL) || *cmajor < 0)
     95 			return (EINVAL);
     96 
     97 		if ((*bmajor >= 0 && bdevsw[*bmajor] != NULL) ||
     98 		    cdevsw[*cmajor] != NULL)
     99 			return (EEXIST);
    100 
    101 		if (bdev != NULL)
    102 			bdevsw[*bmajor] = bdev;
    103 		cdevsw[*cmajor] = cdev;
    104 
    105 		return (0);
    106 	}
    107 
    108 	error = bdevsw_attach(devname, bdev, bmajor);
    109 	if (error != 0)
    110 		return (error);
    111 	error = cdevsw_attach(devname, cdev, cmajor);
    112 	if (error != 0) {
    113 		devsw_detach(bdev, NULL);
    114 		return (error);
    115 	}
    116 
    117 	for (i = 0 ; i < max_devsw_convs ; i++) {
    118 		if (devsw_conv[i].d_name == NULL)
    119 			break;
    120 	}
    121 	if (i == max_devsw_convs) {
    122 		struct devsw_conv *newptr;
    123 		int old, new;
    124 
    125 		old = max_devsw_convs;
    126 		new = old + 1;
    127 
    128 		newptr = malloc(new * DEVSWCONV_SIZE, M_DEVBUF, M_NOWAIT);
    129 		if (newptr == NULL) {
    130 			devsw_detach(bdev, cdev);
    131 			return (ENOMEM);
    132 		}
    133 		newptr[old].d_name = NULL;
    134 		newptr[old].d_bmajor = -1;
    135 		newptr[old].d_cmajor = -1;
    136 		memcpy(newptr, devsw_conv, old * DEVSWCONV_SIZE);
    137 		if (devsw_conv != devsw_conv0)
    138 			free(devsw_conv, M_DEVBUF);
    139 		devsw_conv = newptr;
    140 		max_devsw_convs = new;
    141 	}
    142 
    143 	name = malloc(strlen(devname) + 1, M_DEVBUF, M_NOWAIT);
    144 	if (name == NULL) {
    145 		devsw_detach(bdev, cdev);
    146 		return (ENOMEM);
    147 	}
    148 	strcpy(name, devname);
    149 
    150 	devsw_conv[i].d_name = name;
    151 	devsw_conv[i].d_bmajor = *bmajor;
    152 	devsw_conv[i].d_cmajor = *cmajor;
    153 
    154 	return (0);
    155 }
    156 
    157 static int
    158 bdevsw_attach(const char *devname, const struct bdevsw *devsw, int *devmajor)
    159 {
    160 	int bmajor, i;
    161 
    162 	if (devsw == NULL)
    163 		return (0);
    164 
    165 	if (*devmajor < 0) {
    166 		for (bmajor = sys_bdevsws ; bmajor < max_bdevsws ; bmajor++) {
    167 			if (bdevsw[bmajor] != NULL)
    168 				continue;
    169 			for (i = 0 ; i < max_devsw_convs ; i++) {
    170 				if (devsw_conv[i].d_bmajor == bmajor)
    171 					break;
    172 			}
    173 			if (i != max_devsw_convs)
    174 				continue;
    175 			break;
    176 		}
    177 		*devmajor = bmajor;
    178 	}
    179 	if (*devmajor >= MAXDEVSW) {
    180 #ifdef DEVSW_DEBUG
    181 		panic("bdevsw_attach: block majors exhausted");
    182 #endif /* DEVSW_DEBUG */
    183 		return (ENOMEM);
    184 	}
    185 
    186 	if (*devmajor >= max_bdevsws) {
    187 		const struct bdevsw **newptr;
    188 		int old, new;
    189 
    190 		old = max_bdevsws;
    191 		new = *devmajor + 1;
    192 
    193 		newptr = malloc(new * BDEVSW_SIZE, M_DEVBUF, M_NOWAIT);
    194 		if (newptr == NULL)
    195 			return (ENOMEM);
    196 		memset(newptr + old, 0, (new - old) * BDEVSW_SIZE);
    197 		if (old != 0) {
    198 			memcpy(newptr, bdevsw, old * BDEVSW_SIZE);
    199 			if (bdevsw != bdevsw0)
    200 				free(bdevsw, M_DEVBUF);
    201 		}
    202 		bdevsw = newptr;
    203 		max_bdevsws = new;
    204 	}
    205 
    206 	if (bdevsw[*devmajor] != NULL)
    207 		return (EEXIST);
    208 
    209 	bdevsw[*devmajor] = devsw;
    210 
    211 	return (0);
    212 }
    213 
    214 static int
    215 cdevsw_attach(const char *devname, const struct cdevsw *devsw, int *devmajor)
    216 {
    217 	int cmajor, i;
    218 
    219 	if (*devmajor < 0) {
    220 		for (cmajor = sys_cdevsws ; cmajor < max_cdevsws ; cmajor++) {
    221 			if (cdevsw[cmajor] != NULL)
    222 				continue;
    223 			for (i = 0 ; i < max_devsw_convs ; i++) {
    224 				if (devsw_conv[i].d_cmajor == cmajor)
    225 					break;
    226 			}
    227 			if (i != max_devsw_convs)
    228 				continue;
    229 			break;
    230 		}
    231 		*devmajor = cmajor;
    232 	}
    233 	if (*devmajor >= MAXDEVSW) {
    234 #ifdef DEVSW_DEBUG
    235 		panic("cdevsw_attach: character majors exhausted");
    236 #endif /* DEVSW_DEBUG */
    237 		return (ENOMEM);
    238 	}
    239 
    240 	if (*devmajor >= max_cdevsws) {
    241 		const struct cdevsw **newptr;
    242 		int old, new;
    243 
    244 		old = max_cdevsws;
    245 		new = *devmajor + 1;
    246 
    247 		newptr = malloc(new * CDEVSW_SIZE, M_DEVBUF, M_NOWAIT);
    248 		if (newptr == NULL)
    249 			return (ENOMEM);
    250 		memset(newptr + old, 0, (new - old) * CDEVSW_SIZE);
    251 		if (old != 0) {
    252 			memcpy(newptr, cdevsw, old * CDEVSW_SIZE);
    253 			if (cdevsw != cdevsw0)
    254 				free(cdevsw, M_DEVBUF);
    255 		}
    256 		cdevsw = newptr;
    257 		max_cdevsws = new;
    258 	}
    259 
    260 	if (cdevsw[*devmajor] != NULL)
    261 		return (EEXIST);
    262 
    263 	cdevsw[*devmajor] = devsw;
    264 
    265 	return (0);
    266 }
    267 
    268 void
    269 devsw_detach(const struct bdevsw *bdev, const struct cdevsw *cdev)
    270 {
    271 	int i;
    272 
    273 	if (bdev != NULL) {
    274 		for (i = 0 ; i < max_bdevsws ; i++) {
    275 			if (bdevsw[i] != bdev)
    276 				continue;
    277 			bdevsw[i] = NULL;
    278 			break;
    279 		}
    280 	}
    281 	if (cdev != NULL) {
    282 		for (i = 0 ; i < max_cdevsws ; i++) {
    283 			if (cdevsw[i] != cdev)
    284 				continue;
    285 			cdevsw[i] = NULL;
    286 			break;
    287 		}
    288 	}
    289 }
    290 
    291 const struct bdevsw *
    292 bdevsw_lookup(dev_t dev)
    293 {
    294 	int bmajor;
    295 
    296 	if (dev == NODEV)
    297 		return (NULL);
    298 	bmajor = major(dev);
    299 	if (bmajor < 0 || bmajor >= max_bdevsws)
    300 		return (NULL);
    301 
    302 	return (bdevsw[bmajor]);
    303 }
    304 
    305 const struct cdevsw *
    306 cdevsw_lookup(dev_t dev)
    307 {
    308 	int cmajor;
    309 
    310 	if (dev == NODEV)
    311 		return (NULL);
    312 	cmajor = major(dev);
    313 	if (cmajor < 0 || cmajor >= max_cdevsws)
    314 		return (NULL);
    315 
    316 	return (cdevsw[cmajor]);
    317 }
    318 
    319 int
    320 bdevsw_lookup_major(const struct bdevsw *bdev)
    321 {
    322 	int bmajor;
    323 
    324 	for (bmajor = 0 ; bmajor < max_bdevsws ; bmajor++) {
    325 		if (bdevsw[bmajor] == bdev)
    326 			return (bmajor);
    327 	}
    328 
    329 	return (-1);
    330 }
    331 
    332 int
    333 cdevsw_lookup_major(const struct cdevsw *cdev)
    334 {
    335 	int cmajor;
    336 
    337 	for (cmajor = 0 ; cmajor < max_cdevsws ; cmajor++) {
    338 		if (cdevsw[cmajor] == cdev)
    339 			return (cmajor);
    340 	}
    341 
    342 	return (-1);
    343 }
    344 
    345 /*
    346  * Convert from block major number to name.
    347  */
    348 const char *
    349 devsw_blk2name(int bmajor)
    350 {
    351 	int cmajor, i;
    352 
    353 	if (bmajor < 0 || bmajor >= max_bdevsws || bdevsw[bmajor] == NULL)
    354 		return (NULL);
    355 
    356 	for (i = 0 ; i < max_devsw_convs ; i++) {
    357 		if (devsw_conv[i].d_bmajor != bmajor)
    358 			continue;
    359 		cmajor = devsw_conv[i].d_cmajor;
    360 		if (cmajor < 0 || cmajor >= max_cdevsws ||
    361 		    cdevsw[cmajor] == NULL)
    362 			return (NULL);
    363 		return (devsw_conv[i].d_name);
    364 	}
    365 
    366 	return (NULL);
    367 }
    368 
    369 /*
    370  * Convert from device name to block major number.
    371  */
    372 int
    373 devsw_name2blk(const char *name, char *devname, size_t devnamelen)
    374 {
    375 	struct devsw_conv *conv;
    376 	int bmajor, i;
    377 
    378 	if (name == NULL)
    379 		return (-1);
    380 
    381 	for (i = 0 ; i < max_devsw_convs ; i++) {
    382 		size_t len;
    383 
    384 		conv = &devsw_conv[i];
    385 		if (conv->d_name == NULL)
    386 			continue;
    387 		len = strlen(conv->d_name);
    388 		if (strncmp(conv->d_name, name, len) != 0)
    389 			continue;
    390 		if (*(name +len) && !isdigit(*(name + len)))
    391 			continue;
    392 		bmajor = conv->d_bmajor;
    393 		if (bmajor < 0 || bmajor >= max_bdevsws ||
    394 		    bdevsw[bmajor] == NULL)
    395 			break;
    396 		if (devname != NULL) {
    397 #ifdef DEVSW_DEBUG
    398 			if (strlen(conv->d_name) >= devnamelen)
    399 				printf("devsw_name2blk: too short buffer");
    400 #endif /* DEVSW_DEBUG */
    401 			strncpy(devname, conv->d_name, devnamelen);
    402 			devname[devnamelen - 1] = '\0';
    403 		}
    404 		return (bmajor);
    405 	}
    406 
    407 	return (-1);
    408 }
    409 
    410 /*
    411  * Convert from character dev_t to block dev_t.
    412  */
    413 dev_t
    414 devsw_chr2blk(dev_t cdev)
    415 {
    416 	int bmajor, cmajor, i;
    417 
    418 	if (cdevsw_lookup(cdev) == NULL)
    419 		return (NODEV);
    420 
    421 	cmajor = major(cdev);
    422 
    423 	for (i = 0 ; i < max_devsw_convs ; i++) {
    424 		if (devsw_conv[i].d_cmajor != cmajor)
    425 			continue;
    426 		bmajor = devsw_conv[i].d_bmajor;
    427 		if (bmajor < 0 || bmajor >= max_bdevsws ||
    428 		    bdevsw[bmajor] == NULL)
    429 			return (NODEV);
    430 		return (makedev(bmajor, minor(cdev)));
    431 	}
    432 
    433 	return (NODEV);
    434 }
    435 
    436 /*
    437  * Convert from block dev_t to character dev_t.
    438  */
    439 dev_t
    440 devsw_blk2chr(dev_t bdev)
    441 {
    442 	int bmajor, cmajor, i;
    443 
    444 	if (bdevsw_lookup(bdev) == NULL)
    445 		return (NODEV);
    446 
    447 	bmajor = major(bdev);
    448 
    449 	for (i = 0 ; i < max_devsw_convs ; i++) {
    450 		if (devsw_conv[i].d_bmajor != bmajor)
    451 			continue;
    452 		cmajor = devsw_conv[i].d_cmajor;
    453 		if (cmajor < 0 || cmajor >= max_cdevsws ||
    454 		    cdevsw[cmajor] == NULL)
    455 			return (NODEV);
    456 		return (makedev(cmajor, minor(bdev)));
    457 	}
    458 
    459 	return (NODEV);
    460 }
    461