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 struct stat st; 59 char *path = NULL; 60 int stgood = 0; 61 62 if (devname[0] == '/' || devname[0] == '.') { 63 asprintf(&path, "%s", devname); 64 } else { 65 asprintf(&path, "/dev/%s", devname); 66 if (lstat(path, &st) < 0) { 67 free(path); 68 path = NULL; 69 finddevlabel(&path, devname); 70 if (path == NULL) 71 asprintf(&path, "%s", devname); 72 } else { 73 stgood = 1; 74 } 75 } 76 77 /* 78 * Translate softlinks if requested. If the lstat() of the 79 * pre-translated path fails NULL is expected to be returned. 80 * lstat() is not called on the post-translated path. 81 */ 82 if ((flags & GETDEVPATH_RAWDEV) && path) { 83 if (stgood == 0 && lstat(path, &st) == 0) 84 stgood = 1; 85 if (stgood) 86 stgood = xlatedevpath(&path, &st); 87 if (stgood == 0) { 88 free(path); 89 path = NULL; 90 } 91 92 } 93 if (path == NULL) 94 errno = ENOENT; 95 return(path); 96 } 97 98 static void 99 finddevlabel(char **pathp, const char *devname) 100 { 101 const char *prefix = _PATH_DEVTAB_PATHS; 102 const char *ptr1; 103 const char *trailer; 104 char *label; 105 char *ptr2; 106 char *ptr3; 107 char *dtpath; 108 char *bufp; 109 char buf[256]; 110 FILE *fp; 111 size_t len; /* directory prefix length */ 112 size_t dlen; /* devname length */ 113 size_t tlen; /* devname length without trailer */ 114 115 dlen = strlen(devname); 116 if ((trailer = strrchr(devname, '.')) != NULL) 117 tlen = trailer - devname; 118 else 119 tlen = 0; 120 121 while (*prefix && *pathp == NULL) { 122 /* 123 * Directory search path 124 */ 125 ptr1 = strchr(prefix, ':'); 126 len = (ptr1) ? (size_t)(ptr1 - prefix) : strlen(prefix); 127 asprintf(&dtpath, "%*.*s/devtab", len, len, prefix); 128 129 /* 130 * Each devtab file 131 */ 132 if ((fp = fopen(dtpath, "r")) != NULL) { 133 while (fgets(buf, sizeof(buf), fp) != NULL) { 134 /* 135 * Extract label field, check degenerate 136 * cases. 137 */ 138 label = strtok_r(buf, " \t\r\n", &bufp); 139 if (label == NULL || *label == 0 || 140 *label == '#') { 141 continue; 142 } 143 144 /* 145 * Match label, with or without the 146 * trailer (aka ".s1a"). The trailer 147 * is tacked on if the match is without 148 * the trailer. 149 */ 150 if (strcmp(devname, label) == 0) { 151 trailer = ""; 152 } else if (tlen && strlen(label) == tlen && 153 strncmp(devname, label, tlen) == 0) { 154 trailer = devname + tlen; 155 } else { 156 continue; 157 } 158 159 /* 160 * Match, extract and process remaining fields. 161 */ 162 ptr2 = strtok_r(NULL, " \t\r\n", &bufp); 163 ptr3 = strtok_r(NULL, " \t\r\n", &bufp); 164 if (ptr2 == NULL || ptr3 == NULL) 165 continue; 166 if (*ptr2 == 0 || *ptr3 == 0) 167 continue; 168 ptr3 = dodequote(ptr3); 169 if (strcmp(ptr2, "path") == 0) { 170 asprintf(pathp, "%s%s", ptr3, trailer); 171 } else { 172 asprintf(pathp, "/dev/%s/%s%s", 173 ptr2, ptr3, trailer); 174 } 175 break; 176 } 177 fclose(fp); 178 } 179 free(dtpath); 180 prefix += len; 181 if (*prefix == ':') 182 ++prefix; 183 } 184 } 185 186 static int 187 xlatedevpath(char **pathp, struct stat *st) 188 { 189 char *path; 190 int n; 191 int len; 192 193 /* 194 * If not a softlink return unchanged. 195 */ 196 if (!S_ISLNK(st->st_mode)) 197 return(1); 198 199 /* 200 * If the softlink isn't reasonable return bad (0) 201 */ 202 len = (int)st->st_size; 203 if (len < 0 || len > PATH_MAX) 204 return(0); 205 206 /* 207 * Read the link, return if the result is not what we expected. 208 */ 209 path = malloc(len + 1); 210 n = readlink(*pathp, path, len); 211 if (n < 0 || n > len) { 212 free(path); 213 return(0); 214 } 215 216 /* 217 * Success, replace (*pathp). 218 */ 219 path[n] = 0; 220 free(*pathp); 221 *pathp = path; 222 return(1); 223 } 224 225 static char * 226 dodequote(char *base) 227 { 228 int len = strlen(base); 229 230 if (len && base[0] == '\"' && base[len-1] == '\"') { 231 base[len - 1] = 0; 232 ++base; 233 } 234 return(base); 235 } 236