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 (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26 /* Copyright (c) 1988 AT&T */
27 /* All Rights Reserved */
28
29 #include "lint.h"
30 #include <sys/types.h>
31 #include <dirent.h>
32 #include <sys/param.h>
33 #include <limits.h>
34 #include <errno.h>
35 #include <stdlib.h>
36 #include <unistd.h>
37 #include <string.h>
38
39 /*
40 * Canonicalize the path given in file_name, resolving away all symbolic link
41 * components. Store the result into the buffer named by resolved_name, which
42 * must be long enough (PATH_MAX bytes will suffice). Returns NULL
43 * on failure and resolved_name on success. On failure, to maintain
44 * compatibility with the past, the contents of file_name will be copied
45 * into resolved_name.
46 */
47 static char *
realpath_impl(const char * file_name,char * resolved_name)48 realpath_impl(const char *file_name, char *resolved_name)
49 {
50 char cwd[PATH_MAX];
51 int len;
52
53 if (file_name == NULL) {
54 errno = EINVAL;
55 return (NULL);
56 }
57
58 /*
59 * Call resolvepath() to resolve all the symlinks in file_name,
60 * eliminate embedded "." components, and collapse embedded ".."
61 * components. We may be left with leading ".." components.
62 */
63 if ((len = resolvepath(file_name, resolved_name, PATH_MAX)) < 0) {
64 (void) strlcpy(resolved_name, file_name, PATH_MAX);
65 return (NULL); /* errno set by resolvepath() */
66 }
67
68 if (len >= PATH_MAX) /* "can't happen" */
69 len = PATH_MAX - 1;
70 resolved_name[len] = '\0';
71
72 if (*resolved_name == '/') /* nothing more to do */
73 return (resolved_name);
74
75 /*
76 * Prepend the current working directory to the relative path.
77 * If the relative path is not empty (or "."), collapse all of the
78 * resulting embedded ".." components with trailing cwd components.
79 * We know that getcwd() returns a path name free of symlinks.
80 */
81 if (getcwd(cwd, sizeof (cwd)) == NULL) {
82 (void) strlcpy(resolved_name, file_name, PATH_MAX);
83 return (NULL); /* errno set by getcwd() */
84 }
85
86 if (len != 0 && strcmp(resolved_name, ".") != 0) {
87 char *relpath = resolved_name;
88 char *endcwd = cwd + strlen(cwd);
89
90 /*
91 * Eliminate ".." components from the relative path
92 * left-to-right, components from cwd right-to-left.
93 */
94 relpath[len++] = '/';
95 while (len >= 3 && strncmp(relpath, "../", 3) == 0) {
96 relpath += 3;
97 len -= 3;
98 while (*--endcwd != '/')
99 continue;
100 }
101 if (len == 0) {
102 /* the relative path was all ".." components */
103 *endcwd = '\0';
104 } else {
105 /* there are non-null components on both sides */
106 relpath[--len] = '\0';
107 *endcwd++ = '/';
108 if (endcwd + len >= cwd + PATH_MAX) {
109 (void) strlcpy(resolved_name,
110 file_name, PATH_MAX);
111 errno = ENAMETOOLONG;
112 return (NULL);
113 }
114 (void) strcpy(endcwd, relpath);
115 }
116 }
117
118 (void) strcpy(resolved_name, cwd);
119 return (resolved_name);
120 }
121
122 /*
123 * Canonicalize the path given in file_name, resolving away all symbolic link
124 * components. If resolved_name is a null pointer, return a malloc()d
125 * buffer containing the result, else store the result into resolved_name
126 * and return resolved_name. Return NULL on failure.
127 */
128 char *
realpath(const char * file_name,char * resolved_name)129 realpath(const char *file_name, char *resolved_name)
130 {
131 char buffer[PATH_MAX];
132
133 if (resolved_name != NULL)
134 return (realpath_impl(file_name, resolved_name));
135
136 if (realpath_impl(file_name, buffer) != NULL)
137 return (strdup(buffer));
138
139 return (NULL);
140 }
141
142 /*
143 * GNU extension.
144 */
145 char *
canonicalize_file_name(const char * path)146 canonicalize_file_name(const char *path)
147 {
148 return (realpath(path, NULL));
149 }
150