1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru> 28 * 29 * Redistribution and use in source and binary forms, with or without 30 * modification, are permitted provided that the following conditions 31 * are met: 32 * 1. Redistributions of source code must retain the above copyright 33 * notice, this list of conditions and the following disclaimer. 34 * 2. Redistributions in binary form must reproduce the above copyright 35 * notice, this list of conditions and the following disclaimer in the 36 * documentation and/or other materials provided with the distribution. 37 * 3. The names of the authors may not be used to endorse or promote 38 * products derived from this software without specific prior written 39 * permission. 40 * 41 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 */ 53 /* 54 * http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib/realpath.c 55 * $OpenBSD: realpath.c,v 1.13 2005/08/08 08:05:37 espie Exp $ 56 */ 57 58 #include <stdio.h> 59 #include <unistd.h> 60 #include <string.h> 61 #include <limits.h> 62 #include <errno.h> 63 #include <sys/types.h> 64 #include <sys/stat.h> 65 #include <sys/param.h> 66 67 /* 68 * char *s_realpath(const char *path, char resolved_path[MAXPATHLEN]); 69 * 70 * Find the real name of path, by removing all ".", ".." and symlink 71 * components. Returns (resolved) on success, or (NULL) on failure, 72 * in which case the path which caused trouble is left in (resolved). 73 * 74 * DEVINFO: For libdevinfo we have added code to special case symlinks into 75 * /devices - the path below that point is known to not point to any 76 * additional symlinks. This knowledge allows us to avoid causing attach. 77 */ 78 char * 79 s_realpath(const char *path, char *resolved) 80 { 81 struct stat sb; 82 char *p, *q, *s; 83 size_t left_len, resolved_len; 84 unsigned symlinks; 85 int serrno, slen; 86 char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; 87 88 serrno = errno; 89 symlinks = 0; 90 if (path[0] == '/') { 91 resolved[0] = '/'; 92 resolved[1] = '\0'; 93 if (path[1] == '\0') 94 return (resolved); 95 resolved_len = 1; 96 left_len = strlcpy(left, path + 1, sizeof (left)); 97 } else { 98 if (getcwd(resolved, PATH_MAX) == NULL) { 99 (void) strlcpy(resolved, ".", PATH_MAX); 100 return (NULL); 101 } 102 resolved_len = strlen(resolved); 103 left_len = strlcpy(left, path, sizeof (left)); 104 } 105 if (left_len >= sizeof (left) || resolved_len >= PATH_MAX) { 106 errno = ENAMETOOLONG; 107 return (NULL); 108 } 109 110 /* 111 * Iterate over path components in `left'. 112 */ 113 while (left_len != 0) { 114 /* 115 * Extract the next path component and adjust `left' 116 * and its length. 117 */ 118 p = strchr(left, '/'); 119 s = p ? p : left + left_len; 120 if (s - left >= sizeof (next_token)) { 121 errno = ENAMETOOLONG; 122 return (NULL); 123 } 124 (void) memcpy(next_token, left, s - left); 125 next_token[s - left] = '\0'; 126 left_len -= s - left; 127 if (p != NULL) 128 (void) memmove(left, s + 1, left_len + 1); 129 if (resolved[resolved_len - 1] != '/') { 130 if (resolved_len + 1 >= PATH_MAX) { 131 errno = ENAMETOOLONG; 132 return (NULL); 133 } 134 resolved[resolved_len++] = '/'; 135 resolved[resolved_len] = '\0'; 136 } 137 if (next_token[0] == '\0') 138 continue; 139 else if (strcmp(next_token, ".") == 0) 140 continue; 141 else if (strcmp(next_token, "..") == 0) { 142 /* 143 * Strip the last path component except when we have 144 * single "/" 145 */ 146 if (resolved_len > 1) { 147 resolved[resolved_len - 1] = '\0'; 148 q = strrchr(resolved, '/') + 1; 149 *q = '\0'; 150 resolved_len = q - resolved; 151 } 152 continue; 153 } 154 155 /* 156 * Append the next path component and lstat() it. If 157 * lstat() fails we still can return successfully if 158 * there are no more path components left. 159 */ 160 resolved_len = strlcat(resolved, next_token, PATH_MAX); 161 if (resolved_len >= PATH_MAX) { 162 errno = ENAMETOOLONG; 163 return (NULL); 164 } 165 166 /* 167 * DEVINFO: Check if link points into /devices and resolve 168 * without causing attach if that is the case - there are no 169 * further symlinks in /devices. 170 */ 171 if (strcmp(resolved, "/devices") == 0) { 172 resolved[resolved_len] = '/'; 173 resolved_len = strlcat(resolved, left, sizeof (left)); 174 left_len = 0; 175 continue; 176 } 177 178 if (lstat(resolved, &sb) != 0) { 179 if (errno == ENOENT && p == NULL) { 180 errno = serrno; 181 return (resolved); 182 } 183 return (NULL); 184 } 185 186 if (S_ISLNK(sb.st_mode)) { 187 if (symlinks++ > MAXSYMLINKS) { 188 errno = ELOOP; 189 return (NULL); 190 } 191 slen = readlink(resolved, symlink, 192 sizeof (symlink) - 1); 193 if (slen < 0) 194 return (NULL); 195 symlink[slen] = '\0'; 196 197 if (symlink[0] == '/') { 198 resolved[1] = 0; 199 resolved_len = 1; 200 } else if (resolved_len > 1) { 201 /* Strip the last path component. */ 202 resolved[resolved_len - 1] = '\0'; 203 q = strrchr(resolved, '/') + 1; 204 *q = '\0'; 205 resolved_len = q - resolved; 206 } 207 208 /* 209 * If there are any path components left, then 210 * append them to symlink. The result is placed 211 * in `left'. 212 */ 213 if (p != NULL) { 214 if (symlink[slen - 1] != '/') { 215 if (slen + 1 >= sizeof (symlink)) { 216 errno = ENAMETOOLONG; 217 return (NULL); 218 } 219 symlink[slen] = '/'; 220 symlink[slen + 1] = 0; 221 } 222 left_len = strlcat(symlink, left, 223 sizeof (left)); 224 if (left_len >= sizeof (left)) { 225 errno = ENAMETOOLONG; 226 return (NULL); 227 } 228 } 229 left_len = strlcpy(left, symlink, sizeof (left)); 230 } 231 } 232 233 /* 234 * Remove trailing slash except when the resolved pathname 235 * is a single "/". 236 */ 237 if (resolved_len > 1 && resolved[resolved_len - 1] == '/') 238 resolved[resolved_len - 1] = '\0'; 239 return (resolved); 240 } 241