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