1 /* 2 * Copyright (c) 2009 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/types.h> 36 #include <sys/stat.h> 37 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 #include <errno.h> 43 #include <paths.h> 44 #include <limits.h> 45 #include <fstab.h> 46 47 static void finddevlabel(char **pathp, const char *devname); 48 static int xlatedevpath(char **pathp, struct stat *st); 49 static char *dodequote(char *base); 50 51 /* 52 * Acquire device path. 53 * 54 */ 55 char * 56 getdevpath(const char *devname, int flags) 57 { 58 const char *ptr; 59 struct stat st; 60 char *path = NULL; 61 int stgood = 0; 62 63 if (devname[0] == '/' || devname[0] == '.') { 64 asprintf(&path, "%s", devname); 65 } else { 66 asprintf(&path, "/dev/%s", devname); 67 if (lstat(path, &st) < 0) { 68 free(path); 69 path = NULL; 70 finddevlabel(&path, devname); 71 if (path == NULL) 72 asprintf(&path, "%s", devname); 73 } else { 74 stgood = 1; 75 } 76 } 77 78 /* 79 * Translate softlinks if requested. If the lstat() of the 80 * pre-translated path fails NULL is expected to be returned. 81 * lstat() is not called on the post-translated path. 82 */ 83 if ((flags & GETDEVPATH_RAWDEV) && path) { 84 if (stgood == 0 && lstat(path, &st) == 0) 85 stgood = 1; 86 if (stgood) 87 stgood = xlatedevpath(&path, &st); 88 if (stgood == 0) { 89 free(path); 90 path = NULL; 91 } 92 93 } 94 if (path == NULL) 95 errno = ENOENT; 96 return(path); 97 } 98 99 static void 100 finddevlabel(char **pathp, const char *devname) 101 { 102 const char *prefix = _PATH_DEVTAB_PATHS; 103 const char *ptr1; 104 const char *trailer; 105 char *label; 106 char *ptr2; 107 char *ptr3; 108 char *dtpath; 109 char *bufp; 110 char buf[256]; 111 FILE *fp; 112 size_t len; /* directory prefix length */ 113 size_t dlen; /* devname length */ 114 size_t tlen; /* devname length without trailer */ 115 116 dlen = strlen(devname); 117 if ((trailer = strrchr(devname, '.')) != NULL) 118 tlen = trailer - devname; 119 else 120 tlen = 0; 121 122 while (*prefix && *pathp == NULL) { 123 /* 124 * Directory search path 125 */ 126 ptr1 = strchr(prefix, ':'); 127 len = (ptr1) ? (size_t)(ptr1 - prefix) : strlen(prefix); 128 asprintf(&dtpath, "%*.*s/devtab", len, len, prefix); 129 130 /* 131 * Each devtab file 132 */ 133 if ((fp = fopen(dtpath, "r")) != NULL) { 134 while (fgets(buf, sizeof(buf), fp) != NULL) { 135 /* 136 * Extract label field, check degenerate 137 * cases. 138 */ 139 label = strtok_r(buf, " \t\r\n", &bufp); 140 if (label == NULL || *label == 0 || 141 *label == '#') { 142 continue; 143 } 144 145 /* 146 * Match label, with or without the 147 * trailer (aka ".s1a"). The trailer 148 * is tacked on if the match is without 149 * the trailer. 150 */ 151 if (strcmp(devname, label) == 0) { 152 trailer = ""; 153 } else if (tlen && strlen(label) == tlen && 154 strncmp(devname, label, tlen) == 0) { 155 trailer = devname + tlen; 156 } else { 157 continue; 158 } 159 160 /* 161 * Match, extract and process remaining fields. 162 */ 163 ptr2 = strtok_r(NULL, " \t\r\n", &bufp); 164 ptr3 = strtok_r(NULL, " \t\r\n", &bufp); 165 if (ptr2 == NULL || ptr3 == NULL) 166 continue; 167 if (*ptr2 == 0 || *ptr3 == 0) 168 continue; 169 ptr3 = dodequote(ptr3); 170 if (strcmp(ptr2, "path") == 0) { 171 asprintf(pathp, "%s%s", ptr3, trailer); 172 } else { 173 asprintf(pathp, "/dev/%s/%s%s", 174 ptr2, ptr3, trailer); 175 } 176 break; 177 } 178 fclose(fp); 179 } 180 free(dtpath); 181 prefix += len; 182 if (*prefix == ':') 183 ++prefix; 184 } 185 } 186 187 static int 188 xlatedevpath(char **pathp, struct stat *st) 189 { 190 char *path; 191 int n; 192 int len; 193 194 /* 195 * If not a softlink return unchanged. 196 */ 197 if (!S_ISLNK(st->st_mode)) 198 return(1); 199 200 /* 201 * If the softlink isn't reasonable return bad (0) 202 */ 203 len = (int)st->st_size; 204 if (len < 0 || len > PATH_MAX) 205 return(0); 206 207 /* 208 * Read the link, return if the result is not what we expected. 209 */ 210 path = malloc(len + 1); 211 n = readlink(*pathp, path, len); 212 if (n < 0 || n > len) { 213 free(path); 214 return(0); 215 } 216 217 /* 218 * Success, replace (*pathp). 219 */ 220 path[n] = 0; 221 free(*pathp); 222 *pathp = path; 223 return(1); 224 } 225 226 static char * 227 dodequote(char *base) 228 { 229 int len = strlen(base); 230 231 if (len && base[0] == '\"' && base[len-1] == '\"') { 232 base[len - 1] = 0; 233 ++base; 234 } 235 return(base); 236 } 237