Ben Lindstrom | b4df15d | 2000-10-15 00:17:36 +0000 | [diff] [blame] | 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 1.4 1998/05/18 09:55:19 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 | * S_ISLNK compatibility |
| 49 | */ |
| 50 | #ifndef S_ISLNK |
| 51 | #define S_ISLNK(m) ((m & 0170000) == 0120000) |
| 52 | #endif |
| 53 | |
| 54 | /* |
Ben Lindstrom | 6557152 | 2000-11-16 02:46:20 +0000 | [diff] [blame^] | 55 | * MAXSYMLINKS |
| 56 | */ |
| 57 | #ifndef MAXSYMLINKS |
| 58 | #define MAXSYMLINKS 5 |
| 59 | #endif |
| 60 | |
| 61 | /* |
Ben Lindstrom | b4df15d | 2000-10-15 00:17:36 +0000 | [diff] [blame] | 62 | * char *realpath(const char *path, char resolved_path[MAXPATHLEN]); |
| 63 | * |
| 64 | * Find the real name of path, by removing all ".", ".." and symlink |
| 65 | * components. Returns (resolved) on success, or (NULL) on failure, |
| 66 | * in which case the path which caused trouble is left in (resolved). |
| 67 | */ |
| 68 | char * |
| 69 | realpath(const char *path, char *resolved) |
| 70 | { |
| 71 | struct stat sb; |
| 72 | int fd, n, rootd, serrno = 0; |
| 73 | char *p, *q, wbuf[MAXPATHLEN], start[MAXPATHLEN]; |
| 74 | int symlinks = 0; |
| 75 | |
| 76 | /* Save the starting point. */ |
| 77 | getcwd(start,MAXPATHLEN); |
| 78 | if ((fd = open(".", O_RDONLY)) < 0) { |
| 79 | (void)strcpy(resolved, "."); |
| 80 | return (NULL); |
| 81 | } |
| 82 | close(fd); |
| 83 | |
| 84 | /* |
| 85 | * Find the dirname and basename from the path to be resolved. |
| 86 | * Change directory to the dirname component. |
| 87 | * lstat the basename part. |
| 88 | * if it is a symlink, read in the value and loop. |
| 89 | * if it is a directory, then change to that directory. |
| 90 | * get the current directory name and append the basename. |
| 91 | */ |
| 92 | (void)strncpy(resolved, path, MAXPATHLEN - 1); |
| 93 | resolved[MAXPATHLEN - 1] = '\0'; |
| 94 | loop: |
| 95 | q = strrchr(resolved, '/'); |
| 96 | if (q != NULL) { |
| 97 | p = q + 1; |
| 98 | if (q == resolved) |
| 99 | q = "/"; |
| 100 | else { |
| 101 | do { |
| 102 | --q; |
| 103 | } while (q > resolved && *q == '/'); |
| 104 | q[1] = '\0'; |
| 105 | q = resolved; |
| 106 | } |
| 107 | if (chdir(q) < 0) |
| 108 | goto err1; |
| 109 | } else |
| 110 | p = resolved; |
| 111 | |
| 112 | /* Deal with the last component. */ |
| 113 | if (lstat(p, &sb) == 0) { |
| 114 | if (S_ISLNK(sb.st_mode)) { |
| 115 | if (++symlinks > MAXSYMLINKS) { |
| 116 | serrno = ELOOP; |
| 117 | goto err1; |
| 118 | } |
| 119 | n = readlink(p, resolved, MAXPATHLEN-1); |
| 120 | if (n < 0) |
| 121 | goto err1; |
| 122 | resolved[n] = '\0'; |
| 123 | goto loop; |
| 124 | } |
| 125 | if (S_ISDIR(sb.st_mode)) { |
| 126 | if (chdir(p) < 0) |
| 127 | goto err1; |
| 128 | p = ""; |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | /* |
| 133 | * Save the last component name and get the full pathname of |
| 134 | * the current directory. |
| 135 | */ |
| 136 | (void)strcpy(wbuf, p); |
| 137 | if (getcwd(resolved, MAXPATHLEN) == 0) |
| 138 | goto err1; |
| 139 | |
| 140 | /* |
| 141 | * Join the two strings together, ensuring that the right thing |
| 142 | * happens if the last component is empty, or the dirname is root. |
| 143 | */ |
| 144 | if (resolved[0] == '/' && resolved[1] == '\0') |
| 145 | rootd = 1; |
| 146 | else |
| 147 | rootd = 0; |
| 148 | |
| 149 | if (*wbuf) { |
| 150 | if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) { |
| 151 | serrno = ENAMETOOLONG; |
| 152 | goto err1; |
| 153 | } |
| 154 | if (rootd == 0) |
| 155 | (void)strcat(resolved, "/"); |
| 156 | (void)strcat(resolved, wbuf); |
| 157 | } |
| 158 | |
| 159 | /* Go back to where we came from. */ |
| 160 | if (chdir(start) < 0) { |
| 161 | serrno = errno; |
| 162 | goto err2; |
| 163 | } |
| 164 | return (resolved); |
| 165 | |
| 166 | err1: chdir(start); |
| 167 | err2: errno = serrno; |
| 168 | return (NULL); |
| 169 | } |
| 170 | #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */ |