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 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 #pragma ident "%Z%%M% %I% %E% SMI" 31 32 #include "lint.h" 33 #include <sys/types.h> 34 #include <dirent.h> 35 #include <sys/param.h> 36 #include <limits.h> 37 #include <errno.h> 38 #include <stdlib.h> 39 #include <unistd.h> 40 #include <string.h> 41 42 /* 43 * Canonicalize the path given in file_name, resolving away all symbolic link 44 * components. Store the result into the buffer named by resolved_name, which 45 * must be long enough (MAXPATHLEN bytes will suffice). Returns NULL 46 * on failure and resolved_name on success. On failure, to maintain 47 * compatibility with the past, the contents of file_name will be copied 48 * into resolved_name. 49 */ 50 char * 51 realpath(const char *file_name, char *resolved_name) 52 { 53 char cwd[PATH_MAX]; 54 int len; 55 56 if (file_name == NULL || resolved_name == NULL) { 57 errno = EINVAL; 58 return (NULL); 59 } 60 61 /* 62 * Call resolvepath() to resolve all the symlinks in file_name, 63 * eliminate embedded "." components, and collapse embedded ".." 64 * components. We may be left with leading ".." components. 65 */ 66 if ((len = resolvepath(file_name, resolved_name, PATH_MAX)) < 0) { 67 (void) strlcpy(resolved_name, file_name, PATH_MAX); 68 return (NULL); /* errno set by resolvepath() */ 69 } 70 71 if (len >= PATH_MAX) /* "can't happen" */ 72 len = PATH_MAX - 1; 73 resolved_name[len] = '\0'; 74 75 if (*resolved_name == '/') /* nothing more to do */ 76 return (resolved_name); 77 78 /* 79 * Prepend the current working directory to the relative path. 80 * If the relative path is not empty (or "."), collapse all of the 81 * resulting embedded ".." components with trailing cwd components. 82 * We know that getcwd() returns a path name free of symlinks. 83 */ 84 if (getcwd(cwd, sizeof (cwd)) == NULL) { 85 (void) strlcpy(resolved_name, file_name, PATH_MAX); 86 return (NULL); /* errno set by getcwd() */ 87 } 88 89 if (len != 0 && strcmp(resolved_name, ".") != 0) { 90 char *relpath = resolved_name; 91 char *endcwd = cwd + strlen(cwd); 92 93 /* 94 * Eliminate ".." components from the relative path 95 * left-to-right, components from cwd right-to-left. 96 */ 97 relpath[len++] = '/'; 98 while (len >= 3 && strncmp(relpath, "../", 3) == 0) { 99 relpath += 3; 100 len -= 3; 101 while (*--endcwd != '/') 102 continue; 103 } 104 if (len == 0) { 105 /* the relative path was all ".." components */ 106 *endcwd = '\0'; 107 } else { 108 /* there are non-null components on both sides */ 109 relpath[--len] = '\0'; 110 *endcwd++ = '/'; 111 if (endcwd + len >= cwd + PATH_MAX) { 112 (void) strlcpy(resolved_name, 113 file_name, PATH_MAX); 114 errno = ENAMETOOLONG; 115 return (NULL); 116 } 117 (void) strcpy(endcwd, relpath); 118 } 119 } 120 121 (void) strcpy(resolved_name, cwd); 122 return (resolved_name); 123 } 124