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opendisk.c revision 1.8 
      1 /*	$NetBSD: opendisk.c,v 1.8 2001/11/01 06:53:25 lukem Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1997 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Luke Mewburn.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 __RCSID("$NetBSD: opendisk.c,v 1.8 2001/11/01 06:53:25 lukem Exp $");
     42 #endif
     43 
     44 #include <sys/param.h>
     45 
     46 #include <assert.h>
     47 #include <errno.h>
     48 #include <fcntl.h>
     49 #include <paths.h>
     50 #include <stdio.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 #include <util.h>
     54 
     55 int
     56 opendisk(const char *path, int flags, char *buf, size_t buflen, int iscooked)
     57 {
     58 	struct stat sb;
     59 	int	f, pass, rawpart, serrno;
     60 
     61 	if (buf == NULL) {
     62 		errno = EFAULT;
     63 		return (-1);
     64 	}
     65 	if ((flags & O_CREAT) != 0) {
     66 		errno = EINVAL;
     67 		return (-1);
     68 	}
     69 
     70 	rawpart = getrawpartition();
     71 	if (rawpart < 0)
     72 		return (-1);	/* sysctl(3) in getrawpartition sets errno */
     73 
     74 	for (pass = 0; pass < 4; pass++) {
     75 		switch (pass) {
     76 		case 0:
     77 			snprintf(buf, buflen, "%s", path);
     78 			break;
     79 		case 1:
     80 			snprintf(buf, buflen, "%s%c", path, 'a' + rawpart);
     81 			break;
     82 		case 2:
     83 			if (strchr(path, '/') != NULL)
     84 				return (-1);
     85 			snprintf(buf, buflen, "%s%s%s", _PATH_DEV,
     86 			    iscooked ? "" : "r", path);
     87 			break;
     88 		case 3:
     89 			snprintf(buf, buflen, "%s%s%s%c", _PATH_DEV,
     90 			    iscooked ? "" : "r", path, 'a' + rawpart);
     91 			break;
     92 		}
     93 		f = open(buf, flags);
     94 		if (f == -1 && errno != ENOENT)
     95 			return (-1);
     96 		if (f != -1) {
     97 			if (fstat(f, &sb) == -1) {
     98 				serrno = errno;
     99 				close (f);
    100 				errno = serrno;
    101 				f = -1;
    102 			} else if ((!iscooked && !S_ISCHR(sb.st_mode)) ||
    103 			    	   ( iscooked && !S_ISBLK(sb.st_mode)) ) {
    104 				close (f);
    105 				errno = ENODEV;
    106 				f = -1;
    107 			}
    108 			return (f);
    109 		}
    110 	}
    111 	return (f);
    112 }
    113