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getdiskrawname.c revision 1.2.4.1 
      1 /*	$NetBSD: getdiskrawname.c,v 1.2.4.1 2014/09/22 11:19:20 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #include <sys/cdefs.h>
     32 __RCSID("$NetBSD: getdiskrawname.c,v 1.2.4.1 2014/09/22 11:19:20 martin Exp $");
     33 
     34 #include <sys/stat.h>
     35 
     36 #include <stdio.h>
     37 #include <string.h>
     38 #include <errno.h>
     39 #include <util.h>
     40 #include <limits.h>
     41 #include <unistd.h>
     42 
     43 static const char *
     44 resolve_link(char *buf, size_t bufsiz, const char *name)
     45 {
     46 	const char *dp;
     47 	size_t nlen;
     48 	ssize_t dlen;
     49 
     50 	dlen = readlink(name, buf, bufsiz - 1);
     51 	if (dlen == -1)
     52 		return name;
     53 
     54 	buf[dlen] = '\0';
     55 
     56 	if (buf[0] != '/') {
     57 		dp = strrchr(name, '/');
     58 		if (dp != NULL) {
     59 			nlen = dp - name + 1;
     60 			if (nlen + 1 > bufsiz)
     61 				return NULL;
     62 			if (nlen + dlen + 1 > bufsiz)
     63 				return NULL;
     64 
     65 			memmove(buf + nlen, buf, (size_t)dlen + 1);
     66 			memcpy(buf, name, nlen);
     67 		}
     68 	}
     69 
     70 	return buf;
     71 }
     72 
     73 const char *
     74 getdiskrawname(char *buf, size_t bufsiz, const char *name)
     75 {
     76 	const char *dp;
     77 	struct stat st;
     78 	char dest[PATH_MAX];
     79 
     80 	if ((name = resolve_link(dest, sizeof(dest), name)) == NULL) {
     81 		errno = EINVAL;
     82 		return NULL;
     83 	}
     84 
     85 	dp = strrchr(name, '/');
     86 
     87 	if (stat(name, &st) == -1)
     88 		return NULL;
     89 
     90 	if (!S_ISBLK(st.st_mode)) {
     91 		errno = EFTYPE;
     92 		return NULL;
     93 	}
     94 
     95 	if (dp != NULL)
     96 		(void)snprintf(buf, bufsiz, "%.*s/r%s", (int)(dp - name), name, dp + 1);
     97 	else
     98 		(void)snprintf(buf, bufsiz, "r%s", name);
     99 
    100 	return buf;
    101 }
    102 
    103 const char *
    104 getdiskcookedname(char *buf, size_t bufsiz, const char *name)
    105 {
    106 	const char *dp;
    107 	struct stat st;
    108 	char dest[PATH_MAX];
    109 
    110 	if ((name = resolve_link(dest, sizeof(dest), name)) == NULL) {
    111 		errno = EINVAL;
    112 		return NULL;
    113 	}
    114 
    115 	dp = strrchr(name, '/');
    116 
    117 	if ((dp != NULL && dp[1] != 'r') || (dp == NULL && name[0] != 'r')) {
    118 		errno = EINVAL;
    119 		return NULL;
    120 	}
    121 
    122 	if (stat(name, &st) == -1)
    123 		return NULL;
    124 
    125 	if (!S_ISCHR(st.st_mode)) {
    126 		errno = EFTYPE;
    127 		return NULL;
    128 	}
    129 
    130 	if (dp != NULL)
    131 		(void)snprintf(buf, bufsiz, "%.*s/%s", (int)(dp - name), name, dp + 2);
    132 	else
    133 		(void)snprintf(buf, bufsiz, "%s", name + 1);
    134 
    135 	return buf;
    136 }
    137