1 /*
2 * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.io;
27
28 import java.security.AccessController;
29 import sun.security.action.GetPropertyAction;
30
31
32 class UnixFileSystem extends FileSystem {
33
34 private final char slash;
35 private final char colon;
36 private final String javaHome;
37
38 public UnixFileSystem() {
39 slash = AccessController.doPrivileged(
40 new GetPropertyAction("file.separator")).charAt(0);
41 colon = AccessController.doPrivileged(
42 new GetPropertyAction("path.separator")).charAt(0);
43 javaHome = AccessController.doPrivileged(
44 new GetPropertyAction("java.home"));
45 }
46
47
48 /* -- Normalization and construction -- */
49
50 public char getSeparator() {
51 return slash;
52 }
53
54 public char getPathSeparator() {
55 return colon;
56 }
57
58 /* A normal Unix pathname contains no duplicate slashes and does not end
59 with a slash. It may be the empty string. */
60
61 /* Normalize the given pathname, whose length is len, starting at the given
62 offset; everything before this offset is already normal. */
63 private String normalize(String pathname, int len, int off) {
64 if (len == 0) return pathname;
65 int n = len;
66 while ((n > 0) && (pathname.charAt(n - 1) == '/')) n--;
67 if (n == 0) return "/";
68 StringBuffer sb = new StringBuffer(pathname.length());
69 if (off > 0) sb.append(pathname.substring(0, off));
70 char prevChar = 0;
71 for (int i = off; i < n; i++) {
72 char c = pathname.charAt(i);
73 if ((prevChar == '/') && (c == '/')) continue;
74 sb.append(c);
75 prevChar = c;
76 }
77 return sb.toString();
78 }
79
80 /* Check that the given pathname is normal. If not, invoke the real
81 normalizer on the part of the pathname that requires normalization.
82 This way we iterate through the whole pathname string only once. */
83 public String normalize(String pathname) {
84 int n = pathname.length();
85 char prevChar = 0;
86 for (int i = 0; i < n; i++) {
87 char c = pathname.charAt(i);
88 if ((prevChar == '/') && (c == '/'))
89 return normalize(pathname, n, i - 1);
90 prevChar = c;
91 }
92 if (prevChar == '/') return normalize(pathname, n, n - 1);
93 return pathname;
94 }
95
96 public int prefixLength(String pathname) {
97 if (pathname.length() == 0) return 0;
98 return (pathname.charAt(0) == '/') ? 1 : 0;
99 }
100
101 public String resolve(String parent, String child) {
102 if (child.equals("")) return parent;
103 if (child.charAt(0) == '/') {
104 if (parent.equals("/")) return child;
105 return parent + child;
106 }
107 if (parent.equals("/")) return parent + child;
108 return parent + '/' + child;
109 }
110
111 public String getDefaultParent() {
112 return "/";
113 }
114
115 public String fromURIPath(String path) {
116 String p = path;
117 if (p.endsWith("/") && (p.length() > 1)) {
118 // "/foo/" --> "/foo", but "/" --> "/"
119 p = p.substring(0, p.length() - 1);
120 }
121 return p;
122 }
123
124
125 /* -- Path operations -- */
126
127 public boolean isAbsolute(File f) {
128 return (f.getPrefixLength() != 0);
129 }
130
131 public String resolve(File f) {
132 if (isAbsolute(f)) return f.getPath();
133 return resolve(System.getProperty("user.dir"), f.getPath());
134 }
135
136 // Caches for canonicalization results to improve startup performance.
137 // The first cache handles repeated canonicalizations of the same path
138 // name. The prefix cache handles repeated canonicalizations within the
139 // same directory, and must not create results differing from the true
140 // canonicalization algorithm in canonicalize_md.c. For this reason the
141 // prefix cache is conservative and is not used for complex path names.
142 private ExpiringCache cache = new ExpiringCache();
143 // On Unix symlinks can jump anywhere in the file system, so we only
144 // treat prefixes in java.home as trusted and cacheable in the
145 // canonicalization algorithm
146 private ExpiringCache javaHomePrefixCache = new ExpiringCache();
147
148 public String canonicalize(String path) throws IOException {
149 if (!useCanonCaches) {
150 return canonicalize0(path);
151 } else {
152 String res = cache.get(path);
153 if (res == null) {
154 String dir = null;
155 String resDir = null;
156 if (useCanonPrefixCache) {
157 // Note that this can cause symlinks that should
158 // be resolved to a destination directory to be
159 // resolved to the directory they're contained in
160 dir = parentOrNull(path);
161 if (dir != null) {
162 resDir = javaHomePrefixCache.get(dir);
163 if (resDir != null) {
164 // Hit only in prefix cache; full path is canonical
165 String filename = path.substring(1 + dir.length());
166 res = resDir + slash + filename;
167 cache.put(dir + slash + filename, res);
168 }
169 }
170 }
171 if (res == null) {
172 res = canonicalize0(path);
173 cache.put(path, res);
174 if (useCanonPrefixCache &&
175 dir != null && dir.startsWith(javaHome)) {
176 resDir = parentOrNull(res);
177 // Note that we don't allow a resolved symlink
178 // to elsewhere in java.home to pollute the
179 // prefix cache (java.home prefix cache could
180 // just as easily be a set at this point)
181 if (resDir != null && resDir.equals(dir)) {
182 File f = new File(res);
183 if (f.exists() && !f.isDirectory()) {
184 javaHomePrefixCache.put(dir, resDir);
185 }
186 }
187 }
188 }
189 }
190 return res;
191 }
192 }
193 private native String canonicalize0(String path) throws IOException;
194 // Best-effort attempt to get parent of this path; used for
195 // optimization of filename canonicalization. This must return null for
196 // any cases where the code in canonicalize_md.c would throw an
197 // exception or otherwise deal with non-simple pathnames like handling
198 // of "." and "..". It may conservatively return null in other
199 // situations as well. Returning null will cause the underlying
200 // (expensive) canonicalization routine to be called.
201 static String parentOrNull(String path) {
202 if (path == null) return null;
203 char sep = File.separatorChar;
204 int last = path.length() - 1;
205 int idx = last;
206 int adjacentDots = 0;
207 int nonDotCount = 0;
208 while (idx > 0) {
209 char c = path.charAt(idx);
210 if (c == '.') {
211 if (++adjacentDots >= 2) {
212 // Punt on pathnames containing . and ..
213 return null;
214 }
215 } else if (c == sep) {
216 if (adjacentDots == 1 && nonDotCount == 0) {
217 // Punt on pathnames containing . and ..
218 return null;
219 }
220 if (idx == 0 ||
221 idx >= last - 1 ||
222 path.charAt(idx - 1) == sep) {
223 // Punt on pathnames containing adjacent slashes
224 // toward the end
225 return null;
226 }
227 return path.substring(0, idx);
228 } else {
229 ++nonDotCount;
230 adjacentDots = 0;
231 }
232 --idx;
233 }
234 return null;
235 }
236
237 /* -- Attribute accessors -- */
238
239 public native int getBooleanAttributes0(File f);
240
241 public int getBooleanAttributes(File f) {
242 int rv = getBooleanAttributes0(f);
243 String name = f.getName();
244 boolean hidden = (name.length() > 0) && (name.charAt(0) == '.');
245 return rv | (hidden ? BA_HIDDEN : 0);
246 }
247
248 public native boolean checkAccess(File f, int access);
249 public native long getLastModifiedTime(File f);
250 public native long getLength(File f);
251 public native boolean setPermission(File f, int access, boolean enable, boolean owneronly);
252
253 /* -- File operations -- */
254
255 public native boolean createFileExclusively(String path)
256 throws IOException;
257 public boolean delete(File f) {
258 // Keep canonicalization caches in sync after file deletion
259 // and renaming operations. Could be more clever than this
260 // (i.e., only remove/update affected entries) but probably
261 // not worth it since these entries expire after 30 seconds
262 // anyway.
263 cache.clear();
264 javaHomePrefixCache.clear();
265 return delete0(f);
266 }
267 private native boolean delete0(File f);
268 public native String[] list(File f);
269 public native boolean createDirectory(File f);
270 public boolean rename(File f1, File f2) {
271 // Keep canonicalization caches in sync after file deletion
272 // and renaming operations. Could be more clever than this
273 // (i.e., only remove/update affected entries) but probably
274 // not worth it since these entries expire after 30 seconds
275 // anyway.
276 cache.clear();
277 javaHomePrefixCache.clear();
278 return rename0(f1, f2);
279 }
280 private native boolean rename0(File f1, File f2);
281 public native boolean setLastModifiedTime(File f, long time);
282 public native boolean setReadOnly(File f);
283
284
285 /* -- Filesystem interface -- */
286
287 public File[] listRoots() {
288 try {
289 SecurityManager security = System.getSecurityManager();
290 if (security != null) {
291 security.checkRead("/");
292 }
293 return new File[] { new File("/") };
294 } catch (SecurityException x) {
295 return new File[0];
296 }
297 }
298
299 /* -- Disk usage -- */
300 public native long getSpace(File f, int t);
301
302 /* -- Basic infrastructure -- */
303
304 public int compare(File f1, File f2) {
305 return f1.getPath().compareTo(f2.getPath());
306 }
307
308 public int hashCode(File f) {
309 return f.getPath().hashCode() ^ 1234321;
310 }
311
312
313 private static native void initIDs();
314
315 static {
316 initIDs();
317 }
318
319 }