1/*
2 * Copyright (c) 2009, 2016, 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
26package java.nio.file;
27
28import java.util.Set;
29import java.util.EnumSet;
30import java.security.SecureRandom;
31import java.io.IOException;
32import java.nio.file.attribute.FileAttribute;
33import java.nio.file.attribute.PosixFilePermission;
34import java.nio.file.attribute.PosixFilePermissions;
35import static java.nio.file.attribute.PosixFilePermission.*;
36import sun.security.action.GetPropertyAction;
37
38
39/**
40 * Helper class to support creation of temporary files and directories with
41 * initial attributes.
42 */
43
44class TempFileHelper {
45    private TempFileHelper() { }
46
47    // temporary directory location
48    private static final Path tmpdir =
49        Paths.get(GetPropertyAction.privilegedGetProperty("java.io.tmpdir"));
50
51    private static final boolean isPosix =
52        FileSystems.getDefault().supportedFileAttributeViews().contains("posix");
53
54    // file name generation, same as java.io.File for now
55    private static final SecureRandom random = new SecureRandom();
56    private static Path generatePath(String prefix, String suffix, Path dir) {
57        long n = random.nextLong();
58        String s = prefix + Long.toUnsignedString(n) + suffix;
59        Path name = dir.getFileSystem().getPath(s);
60        // the generated name should be a simple file name
61        if (name.getParent() != null)
62            throw new IllegalArgumentException("Invalid prefix or suffix");
63        return dir.resolve(name);
64    }
65
66    // default file and directory permissions (lazily initialized)
67    private static class PosixPermissions {
68        static final FileAttribute<Set<PosixFilePermission>> filePermissions =
69            PosixFilePermissions.asFileAttribute(EnumSet.of(OWNER_READ, OWNER_WRITE));
70        static final FileAttribute<Set<PosixFilePermission>> dirPermissions =
71            PosixFilePermissions.asFileAttribute(EnumSet
72                .of(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE));
73    }
74
75    /**
76     * Creates a file or directory in the given directory (or in the
77     * temporary directory if dir is {@code null}).
78     */
79    private static Path create(Path dir,
80                               String prefix,
81                               String suffix,
82                               boolean createDirectory,
83                               FileAttribute<?>[] attrs)
84        throws IOException
85    {
86        if (prefix == null)
87            prefix = "";
88        if (suffix == null)
89            suffix = (createDirectory) ? "" : ".tmp";
90        if (dir == null)
91            dir = tmpdir;
92
93        // in POSIX environments use default file and directory permissions
94        // if initial permissions not given by caller.
95        if (isPosix && (dir.getFileSystem() == FileSystems.getDefault())) {
96            if (attrs.length == 0) {
97                // no attributes so use default permissions
98                attrs = new FileAttribute<?>[1];
99                attrs[0] = (createDirectory) ? PosixPermissions.dirPermissions :
100                                               PosixPermissions.filePermissions;
101            } else {
102                // check if posix permissions given; if not use default
103                boolean hasPermissions = false;
104                for (int i=0; i<attrs.length; i++) {
105                    if (attrs[i].name().equals("posix:permissions")) {
106                        hasPermissions = true;
107                        break;
108                    }
109                }
110                if (!hasPermissions) {
111                    FileAttribute<?>[] copy = new FileAttribute<?>[attrs.length+1];
112                    System.arraycopy(attrs, 0, copy, 0, attrs.length);
113                    attrs = copy;
114                    attrs[attrs.length-1] = (createDirectory) ?
115                        PosixPermissions.dirPermissions :
116                        PosixPermissions.filePermissions;
117                }
118            }
119        }
120
121        // loop generating random names until file or directory can be created
122        SecurityManager sm = System.getSecurityManager();
123        for (;;) {
124            Path f;
125            try {
126                f = generatePath(prefix, suffix, dir);
127            } catch (InvalidPathException e) {
128                // don't reveal temporary directory location
129                if (sm != null)
130                    throw new IllegalArgumentException("Invalid prefix or suffix");
131                throw e;
132            }
133            try {
134                if (createDirectory) {
135                    return Files.createDirectory(f, attrs);
136                } else {
137                    return Files.createFile(f, attrs);
138                }
139            } catch (SecurityException e) {
140                // don't reveal temporary directory location
141                if (dir == tmpdir && sm != null)
142                    throw new SecurityException("Unable to create temporary file or directory");
143                throw e;
144            } catch (FileAlreadyExistsException e) {
145                // ignore
146            }
147        }
148    }
149
150    /**
151     * Creates a temporary file in the given directory, or in the
152     * temporary directory if dir is {@code null}.
153     */
154    static Path createTempFile(Path dir,
155                               String prefix,
156                               String suffix,
157                               FileAttribute<?>[] attrs)
158        throws IOException
159    {
160        return create(dir, prefix, suffix, false, attrs);
161    }
162
163    /**
164     * Creates a temporary directory in the given directory, or in the
165     * temporary directory if dir is {@code null}.
166     */
167    static Path createTempDirectory(Path dir,
168                                    String prefix,
169                                    FileAttribute<?>[] attrs)
170        throws IOException
171    {
172        return create(dir, prefix, null, true, attrs);
173    }
174}
175