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      1 /*	$NetBSD: getdiskrawname.c,v 1.6 2019/08/22 20:23:43 brad 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 1.6 2019/08/22 20:23:43 brad 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 /*
     74  * zvol device names look like:
     75  * /dev/zvol/dsk/pool_name/.../volume_name
     76  * /dev/zvol/rdsk/pool_name/.../volume_name
     77  *
     78  * ZFS pools can be divided nearly to infinity
     79  *
     80  * This allows for 16 pool names, which one would hope would be enough
     81  */
     82 #define DISKMAXPARTS 20
     83 static int
     84 calc_zvol_name(char *buf, size_t bufsiz, const char *name, const char *raw)
     85 {
     86 	char copyname[PATH_MAX];
     87 	char *names[DISKMAXPARTS];
     88 	char *last, *p;
     89 	size_t i = 0;
     90 
     91 	strlcpy(copyname, name, sizeof(copyname));
     92 	for (p = strtok_r(copyname, "/", &last); p;
     93 	     p = strtok_r(NULL, "/", &last)) {
     94 		if (i >= DISKMAXPARTS) {
     95 			errno =  ENOSPC;
     96 			return -1;
     97 		}
     98 		names[i++] = p;
     99 	}
    100 
    101 	if (i < 4) {
    102 		errno = EINVAL;
    103 		return -1;
    104 	}
    105 
    106 	snprintf(buf, bufsiz, "/dev/zvol/%sdsk", raw);
    107 	for (size_t j = 3; j < i; j++) {
    108 		strlcat(buf, "/", bufsiz);
    109 		strlcat(buf, names[j], bufsiz);
    110 	}
    111 	return 0;
    112 }
    113 
    114 static int
    115 calc_name(char *buf, size_t bufsiz, const char *name, const char *raw)
    116 {
    117 	int skip = 1;
    118 
    119 	if (strncmp("/dev/zvol/", name, 10) == 0)
    120 		return calc_zvol_name(buf, bufsiz, name, raw);
    121 
    122 	const char *dp = strrchr(name, '/');
    123 	if (!*raw && ((dp != NULL && dp[1] != 'r')
    124 		|| (dp == NULL && name[0] != 'r'))) {
    125 		errno = EINVAL;
    126 		return -1;
    127 	}
    128 	if (raw[0] != 'r')
    129 		skip = 2;
    130 	if (dp != NULL)
    131 		snprintf(buf, bufsiz, "%.*s/%s%s", (int)(dp - name),
    132 		    name, raw, dp + skip);
    133 	else
    134 		snprintf(buf, bufsiz, "%s%s", raw, name);
    135 	return 0;
    136 }
    137 
    138 const char *
    139 getdiskrawname(char *buf, size_t bufsiz, const char *name)
    140 {
    141 	struct stat st;
    142 	char dest[PATH_MAX];
    143 
    144 	if ((name = resolve_link(dest, sizeof(dest), name)) == NULL) {
    145 		errno = EINVAL;
    146 		return NULL;
    147 	}
    148 
    149 	if (stat(name, &st) == -1)
    150 		return NULL;
    151 
    152 	if (!S_ISBLK(st.st_mode)) {
    153 		errno = EFTYPE;
    154 		return NULL;
    155 	}
    156 
    157 	if (calc_name(buf, bufsiz, name, "r") == -1)
    158 		return NULL;
    159 
    160 	return buf;
    161 }
    162 
    163 const char *
    164 getdiskcookedname(char *buf, size_t bufsiz, const char *name)
    165 {
    166 	struct stat st;
    167 	char dest[PATH_MAX];
    168 
    169 	if ((name = resolve_link(dest, sizeof(dest), name)) == NULL) {
    170 		errno = EINVAL;
    171 		return NULL;
    172 	}
    173 
    174 	if (stat(name, &st) == -1)
    175 		return NULL;
    176 
    177 	if (!S_ISCHR(st.st_mode)) {
    178 		errno = EFTYPE;
    179 		return NULL;
    180 	}
    181 
    182 	if (calc_name(buf, bufsiz, name, "") == -1)
    183 		return NULL;
    184 
    185 	return buf;
    186 }
    187