src/java.base/share/classes/java/nio/file/TempFileHelper.java
changeset 47216 71c04702a3d5
parent 41881 b26ea3cb64c5
child 49285 4d2e3f5abb48
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/nio/file/TempFileHelper.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2009, 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.nio.file;
+
+import java.util.Set;
+import java.util.EnumSet;
+import java.security.SecureRandom;
+import java.io.IOException;
+import java.nio.file.attribute.FileAttribute;
+import java.nio.file.attribute.PosixFilePermission;
+import java.nio.file.attribute.PosixFilePermissions;
+import static java.nio.file.attribute.PosixFilePermission.*;
+import sun.security.action.GetPropertyAction;
+
+
+/**
+ * Helper class to support creation of temporary files and directories with
+ * initial attributes.
+ */
+
+class TempFileHelper {
+    private TempFileHelper() { }
+
+    // temporary directory location
+    private static final Path tmpdir =
+        Paths.get(GetPropertyAction.privilegedGetProperty("java.io.tmpdir"));
+
+    private static final boolean isPosix =
+        FileSystems.getDefault().supportedFileAttributeViews().contains("posix");
+
+    // file name generation, same as java.io.File for now
+    private static final SecureRandom random = new SecureRandom();
+    private static Path generatePath(String prefix, String suffix, Path dir) {
+        long n = random.nextLong();
+        String s = prefix + Long.toUnsignedString(n) + suffix;
+        Path name = dir.getFileSystem().getPath(s);
+        // the generated name should be a simple file name
+        if (name.getParent() != null)
+            throw new IllegalArgumentException("Invalid prefix or suffix");
+        return dir.resolve(name);
+    }
+
+    // default file and directory permissions (lazily initialized)
+    private static class PosixPermissions {
+        static final FileAttribute<Set<PosixFilePermission>> filePermissions =
+            PosixFilePermissions.asFileAttribute(EnumSet.of(OWNER_READ, OWNER_WRITE));
+        static final FileAttribute<Set<PosixFilePermission>> dirPermissions =
+            PosixFilePermissions.asFileAttribute(EnumSet
+                .of(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE));
+    }
+
+    /**
+     * Creates a file or directory in the given directory (or in the
+     * temporary directory if dir is {@code null}).
+     */
+    private static Path create(Path dir,
+                               String prefix,
+                               String suffix,
+                               boolean createDirectory,
+                               FileAttribute<?>[] attrs)
+        throws IOException
+    {
+        if (prefix == null)
+            prefix = "";
+        if (suffix == null)
+            suffix = (createDirectory) ? "" : ".tmp";
+        if (dir == null)
+            dir = tmpdir;
+
+        // in POSIX environments use default file and directory permissions
+        // if initial permissions not given by caller.
+        if (isPosix && (dir.getFileSystem() == FileSystems.getDefault())) {
+            if (attrs.length == 0) {
+                // no attributes so use default permissions
+                attrs = new FileAttribute<?>[1];
+                attrs[0] = (createDirectory) ? PosixPermissions.dirPermissions :
+                                               PosixPermissions.filePermissions;
+            } else {
+                // check if posix permissions given; if not use default
+                boolean hasPermissions = false;
+                for (int i=0; i<attrs.length; i++) {
+                    if (attrs[i].name().equals("posix:permissions")) {
+                        hasPermissions = true;
+                        break;
+                    }
+                }
+                if (!hasPermissions) {
+                    FileAttribute<?>[] copy = new FileAttribute<?>[attrs.length+1];
+                    System.arraycopy(attrs, 0, copy, 0, attrs.length);
+                    attrs = copy;
+                    attrs[attrs.length-1] = (createDirectory) ?
+                        PosixPermissions.dirPermissions :
+                        PosixPermissions.filePermissions;
+                }
+            }
+        }
+
+        // loop generating random names until file or directory can be created
+        SecurityManager sm = System.getSecurityManager();
+        for (;;) {
+            Path f;
+            try {
+                f = generatePath(prefix, suffix, dir);
+            } catch (InvalidPathException e) {
+                // don't reveal temporary directory location
+                if (sm != null)
+                    throw new IllegalArgumentException("Invalid prefix or suffix");
+                throw e;
+            }
+            try {
+                if (createDirectory) {
+                    return Files.createDirectory(f, attrs);
+                } else {
+                    return Files.createFile(f, attrs);
+                }
+            } catch (SecurityException e) {
+                // don't reveal temporary directory location
+                if (dir == tmpdir && sm != null)
+                    throw new SecurityException("Unable to create temporary file or directory");
+                throw e;
+            } catch (FileAlreadyExistsException e) {
+                // ignore
+            }
+        }
+    }
+
+    /**
+     * Creates a temporary file in the given directory, or in the
+     * temporary directory if dir is {@code null}.
+     */
+    static Path createTempFile(Path dir,
+                               String prefix,
+                               String suffix,
+                               FileAttribute<?>[] attrs)
+        throws IOException
+    {
+        return create(dir, prefix, suffix, false, attrs);
+    }
+
+    /**
+     * Creates a temporary directory in the given directory, or in the
+     * temporary directory if dir is {@code null}.
+     */
+    static Path createTempDirectory(Path dir,
+                                    String prefix,
+                                    FileAttribute<?>[] attrs)
+        throws IOException
+    {
+        return create(dir, prefix, null, true, attrs);
+    }
+}