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 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 /* 29 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru> 30 * 31 * Redistribution and use in source and binary forms, with or without 32 * modification, are permitted provided that the following conditions 33 * are met: 34 * 1. Redistributions of source code must retain the above copyright 35 * notice, this list of conditions and the following disclaimer. 36 * 2. Redistributions in binary form must reproduce the above copyright 37 * notice, this list of conditions and the following disclaimer in the 38 * documentation and/or other materials provided with the distribution. 39 * 3. The names of the authors may not be used to endorse or promote 40 * products derived from this software without specific prior written 41 * permission. 42 * 43 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 46 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 53 * SUCH DAMAGE. 54 */ 55 /* 56 * http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdlib/realpath.c 57 * $OpenBSD: realpath.c,v 1.13 2005/08/08 08:05:37 espie Exp $ 58 */ 59 60 #include <stdio.h> 61 #include <unistd.h> 62 #include <string.h> 63 #include <limits.h> 64 #include <errno.h> 65 #include <sys/types.h> 66 #include <sys/stat.h> 67 #include <sys/param.h> 68 69 /* 70 * char *s_realpath(const char *path, char resolved_path[MAXPATHLEN]); 71 * 72 * Find the real name of path, by removing all ".", ".." and symlink 73 * components. Returns (resolved) on success, or (NULL) on failure, 74 * in which case the path which caused trouble is left in (resolved). 75 * 76 * DEVINFO: For libdevinfo we have added code to special case symlinks into 77 * /devices - the path below that point is known to not point to any 78 * additional symlinks. This knowledge allows us to avoid causing attach. 79 */ 80 char * 81 s_realpath(const char *path, char *resolved) 82 { 83 struct stat sb; 84 char *p, *q, *s; 85 size_t left_len, resolved_len; 86 unsigned symlinks; 87 int serrno, slen; 88 char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX]; 89 90 serrno = errno; 91 symlinks = 0; 92 if (path[0] == '/') { 93 resolved[0] = '/'; 94 resolved[1] = '\0'; 95 if (path[1] == '\0') 96 return (resolved); 97 resolved_len = 1; 98 left_len = strlcpy(left, path + 1, sizeof (left)); 99 } else { 100 if (getcwd(resolved, PATH_MAX) == NULL) { 101 (void) strlcpy(resolved, ".", PATH_MAX); 102 return (NULL); 103 } 104 resolved_len = strlen(resolved); 105 left_len = strlcpy(left, path, sizeof (left)); 106 } 107 if (left_len >= sizeof (left) || resolved_len >= PATH_MAX) { 108 errno = ENAMETOOLONG; 109 return (NULL); 110 } 111 112 /* 113 * Iterate over path components in `left'. 114 */ 115 while (left_len != 0) { 116 /* 117 * Extract the next path component and adjust `left' 118 * and its length. 119 */ 120 p = strchr(left, '/'); 121 s = p ? p : left + left_len; 122 if (s - left >= sizeof (next_token)) { 123 errno = ENAMETOOLONG; 124 return (NULL); 125 } 126 (void) memcpy(next_token, left, s - left); 127 next_token[s - left] = '\0'; 128 left_len -= s - left; 129 if (p != NULL) 130 (void) memmove(left, s + 1, left_len + 1); 131 if (resolved[resolved_len - 1] != '/') { 132 if (resolved_len + 1 >= PATH_MAX) { 133 errno = ENAMETOOLONG; 134 return (NULL); 135 } 136 resolved[resolved_len++] = '/'; 137 resolved[resolved_len] = '\0'; 138 } 139 if (next_token[0] == '\0') 140 continue; 141 else if (strcmp(next_token, ".") == 0) 142 continue; 143 else if (strcmp(next_token, "..") == 0) { 144 /* 145 * Strip the last path component except when we have 146 * single "/" 147 */ 148 if (resolved_len > 1) { 149 resolved[resolved_len - 1] = '\0'; 150 q = strrchr(resolved, '/') + 1; 151 *q = '\0'; 152 resolved_len = q - resolved; 153 } 154 continue; 155 } 156 157 /* 158 * Append the next path component and lstat() it. If 159 * lstat() fails we still can return successfully if 160 * there are no more path components left. 161 */ 162 resolved_len = strlcat(resolved, next_token, PATH_MAX); 163 if (resolved_len >= PATH_MAX) { 164 errno = ENAMETOOLONG; 165 return (NULL); 166 } 167 168 /* 169 * DEVINFO: Check if link points into /devices and resolve 170 * without causing attach if that is the case - there are no 171 * further symlinks in /devices. 172 */ 173 if (strcmp(resolved, "/devices") == 0) { 174 resolved[resolved_len] = '/'; 175 resolved_len = strlcat(resolved, left, sizeof (left)); 176 left_len = 0; 177 continue; 178 } 179 180 if (lstat(resolved, &sb) != 0) { 181 if (errno == ENOENT && p == NULL) { 182 errno = serrno; 183 return (resolved); 184 } 185 return (NULL); 186 } 187 188 if (S_ISLNK(sb.st_mode)) { 189 if (symlinks++ > MAXSYMLINKS) { 190 errno = ELOOP; 191 return (NULL); 192 } 193 slen = readlink(resolved, symlink, 194 sizeof (symlink) - 1); 195 if (slen < 0) 196 return (NULL); 197 symlink[slen] = '\0'; 198 199 if (symlink[0] == '/') { 200 resolved[1] = 0; 201 resolved_len = 1; 202 } else if (resolved_len > 1) { 203 /* Strip the last path component. */ 204 resolved[resolved_len - 1] = '\0'; 205 q = strrchr(resolved, '/') + 1; 206 *q = '\0'; 207 resolved_len = q - resolved; 208 } 209 210 /* 211 * If there are any path components left, then 212 * append them to symlink. The result is placed 213 * in `left'. 214 */ 215 if (p != NULL) { 216 if (symlink[slen - 1] != '/') { 217 if (slen + 1 >= sizeof (symlink)) { 218 errno = ENAMETOOLONG; 219 return (NULL); 220 } 221 symlink[slen] = '/'; 222 symlink[slen + 1] = 0; 223 } 224 left_len = strlcat(symlink, left, 225 sizeof (left)); 226 if (left_len >= sizeof (left)) { 227 errno = ENAMETOOLONG; 228 return (NULL); 229 } 230 } 231 left_len = strlcpy(left, symlink, sizeof (left)); 232 } 233 } 234 235 /* 236 * Remove trailing slash except when the resolved pathname 237 * is a single "/". 238 */ 239 if (resolved_len > 1 && resolved[resolved_len - 1] == '/') 240 resolved[resolved_len - 1] = '\0'; 241 return (resolved); 242 } 243