1 /* 2 * Copyright (c) 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Jan-Simon Pendry. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 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 the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include "includes.h" 31 32 #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char *rcsid = "$OpenBSD: realpath.c,v 1.7 2002/05/24 21:22:37 deraadt Exp $"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/param.h> 39 #include <sys/stat.h> 40 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 47 /* 48 * MAXSYMLINKS 49 */ 50 #ifndef MAXSYMLINKS 51 #define MAXSYMLINKS 5 52 #endif 53 54 /* 55 * char *realpath(const char *path, char resolved_path[MAXPATHLEN]); 56 * 57 * Find the real name of path, by removing all ".", ".." and symlink 58 * components. Returns (resolved) on success, or (NULL) on failure, 59 * in which case the path which caused trouble is left in (resolved). 60 */ 61 char * 62 realpath(const char *path, char *resolved) 63 { 64 struct stat sb; 65 int fd, n, rootd, serrno = 0; 66 char *p, *q, wbuf[MAXPATHLEN], start[MAXPATHLEN]; 67 int symlinks = 0; 68 69 /* Save the starting point. */ 70 getcwd(start,MAXPATHLEN); 71 if ((fd = open(".", O_RDONLY)) < 0) { 72 (void)strlcpy(resolved, ".", MAXPATHLEN); 73 return (NULL); 74 } 75 close(fd); 76 77 /* Convert "." -> "" to optimize away a needless lstat() and chdir() */ 78 if (path[0] == '.' && path[1] == '\0') 79 path = ""; 80 81 /* 82 * Find the dirname and basename from the path to be resolved. 83 * Change directory to the dirname component. 84 * lstat the basename part. 85 * if it is a symlink, read in the value and loop. 86 * if it is a directory, then change to that directory. 87 * get the current directory name and append the basename. 88 */ 89 strlcpy(resolved, path, MAXPATHLEN); 90 loop: 91 q = strrchr(resolved, '/'); 92 if (q != NULL) { 93 p = q + 1; 94 if (q == resolved) 95 q = "/"; 96 else { 97 do { 98 --q; 99 } while (q > resolved && *q == '/'); 100 q[1] = '\0'; 101 q = resolved; 102 } 103 if (chdir(q) < 0) 104 goto err1; 105 } else 106 p = resolved; 107 108 /* Deal with the last component. */ 109 if (*p != '\0' && lstat(p, &sb) == 0) { 110 if (S_ISLNK(sb.st_mode)) { 111 if (++symlinks > MAXSYMLINKS) { 112 serrno = ELOOP; 113 goto err1; 114 } 115 n = readlink(p, resolved, MAXPATHLEN-1); 116 if (n < 0) 117 goto err1; 118 resolved[n] = '\0'; 119 goto loop; 120 } 121 if (S_ISDIR(sb.st_mode)) { 122 if (chdir(p) < 0) 123 goto err1; 124 p = ""; 125 } 126 } 127 128 /* 129 * Save the last component name and get the full pathname of 130 * the current directory. 131 */ 132 (void)strlcpy(wbuf, p, sizeof wbuf); 133 if (getcwd(resolved, MAXPATHLEN) == 0) 134 goto err1; 135 136 /* 137 * Join the two strings together, ensuring that the right thing 138 * happens if the last component is empty, or the dirname is root. 139 */ 140 if (resolved[0] == '/' && resolved[1] == '\0') 141 rootd = 1; 142 else 143 rootd = 0; 144 145 if (*wbuf) { 146 if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) { 147 serrno = ENAMETOOLONG; 148 goto err1; 149 } 150 if (rootd == 0) 151 (void)strcat(resolved, "/"); 152 (void)strcat(resolved, wbuf); 153 } 154 155 /* Go back to where we came from. */ 156 if (chdir(start) < 0) { 157 serrno = errno; 158 goto err2; 159 } 160 return (resolved); 161 162 err1: chdir(start); 163 err2: errno = serrno; 164 return (NULL); 165 } 166 #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */ 167 168 #pragma ident "%Z%%M% %I% %E% SMI" 169