1 /*
   2  * Copyright (c) 2009, 2013, 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.nio.file;
  27 
  28 import java.util.Set;
  29 import java.util.EnumSet;
  30 import java.security.SecureRandom;
  31 import java.io.IOException;
  32 import java.nio.file.attribute.FileAttribute;
  33 import java.nio.file.attribute.PosixFilePermission;
  34 import java.nio.file.attribute.PosixFilePermissions;
  35 import static java.nio.file.attribute.PosixFilePermission.*;
  36 import sun.security.action.GetPropertyAction;
  37 
  38 
  39 /**
  40  * Helper class to support creation of temporary files and directories with
  41  * initial attributes.
  42  */
  43 
  44 class TempFileHelper {
  45     private TempFileHelper() { }
  46 
  47     // temporary directory location
  48     private static final Path tmpdir =
  49         Paths.get(GetPropertyAction.getProperty("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         n = (n == Long.MIN_VALUE) ? 0 : Math.abs(n);
  59         Path name = dir.getFileSystem().getPath(prefix + Long.toString(n) + suffix);
  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 }