devopen.c

早期freebsd实现

/*-
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)devopen.c	8.1 (Berkeley) 6/10/93
 */

#include <stand/stand.h>

/*
 * Decode the string 'fname', open the device and return the remaining
 * file name if any.
 */
devopen(f, fname, file)
	struct open_file *f;
	char *fname;
	char **file;	/* out */
{
	register char *cp;
	register char *ncp;
	register struct devsw *dp;
	register int c, i;
	int ctlr = 0, unit = 0, part = 0;
	char namebuf[20];
	int rc;

	cp = fname;
	ncp = namebuf;

	/* look for a string like '5/rz0/vmunix' or '5/rz3f/vmunix */
	if ((c = *cp) >= '0' && c <= '9') {
		ctlr = c - '0';
		/* skip the '/' */
		if (*++cp != '/')
			return (ENXIO);
		cp++;
		while ((c = *cp) != '\0') {
			if (c == '/')
				break;
			if (c >= '0' && c <= '9') {
				/* read unit number */
				unit = c - '0';

				/* look for a partition */
				if ((c = *++cp) >= 'a' && c <= 'h') {
					part = c - 'a';
					c = *++cp;
				}
				if (c != '/')
					return (ENXIO);
				break;
			}
			if (ncp < namebuf + sizeof(namebuf) - 1)
				*ncp++ = c;
			cp++;
		}
	} else {
		/* expect a string like 'rz(0,0,0)vmunix' */
		while ((c = *cp) != '\0') {
			if (c == '(') {
				cp++;
				break;
			}
			if (ncp < namebuf + sizeof(namebuf) - 1)
				*ncp++ = c;
			cp++;
		}

		/* get controller number */
		if ((c = *cp) >= '0' && c <= '9') {
			ctlr = c - '0';
			c = *++cp;
		}

		if (c == ',') {
			/* get SCSI device number */
			if ((c = *++cp) >= '0' && c <= '9') {
				unit = c - '0';
				c = *++cp;
			}

			if (c == ',') {
				/* get partition number */
				if ((c = *++cp) >= '0' && c <= '9') {
					part = c - '0';
					c = *++cp;
				}
			}
		}
		if (c != ')')
			return (ENXIO);
		cp++;
	}
	*ncp = '\0';

	for (dp = devsw, i = 0; i < ndevs; dp++, i++)
		if (dp->dv_name && strcmp(namebuf, dp->dv_name) == 0)
			goto fnd;
	printf("Unknown device '%s'\nKnown devices are:", namebuf);
	for (dp = devsw, i = 0; i < ndevs; dp++, i++)
		if (dp->dv_name)
			printf(" %s", dp->dv_name);
	printf("\n");
	return (ENXIO);

fnd:
	rc = (dp->dv_open)(f, ctlr, unit, part);
	if (rc)
		return (rc);

	f->f_dev = dp;
	if (file && *cp != '\0')
		*file = cp;
	return (0);
}