https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2013, 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.io;

import java.net.URI;
import java.nio.file.InvalidPathException;
import java.security.*;
import java.util.Enumeration;
import java.util.List;
import java.util.ArrayList;
import java.util.Vector;
import java.util.Collections;

import sun.nio.fs.DefaultFileSystemProvider;
import sun.security.util.SecurityConstants;


This class represents access to a file or directory.  A FilePermission consists
of a pathname and a set of actions valid for that pathname.


Pathname is the pathname of the file or directory granted the specified
actions. A pathname that ends in "/*" (where "/" is
the file separator character, File.separatorChar) indicates
all the files and directories contained in that directory. A pathname
that ends with "/-" indicates (recursively) all files
and subdirectories contained in that directory. Such a pathname is called
a wildcard pathname. Otherwise, it's a simple pathname.

 A pathname consisting of the special token "<<ALL FILES>>" matches any file.


Note: A pathname consisting of a single "*" indicates all the files
in the current directory, while a pathname consisting of a single "-"
indicates all the files in the current directory and
(recursively) all files and subdirectories contained in the current
directory.


The actions to be granted are passed to the constructor in a string containing
a list of one or more comma-separated keywords. The possible keywords are
"read", "write", "execute", "delete", and "readlink". Their meaning is
defined as follows:


   
 read 
 read permission
   
 write 
 write permission
   
 execute
   
 execute permission. Allows Runtime.exec to
        be called. Corresponds to SecurityManager.checkExec.
   
 delete
   
 delete permission. Allows File.delete to
        be called. Corresponds to SecurityManager.checkDelete.
   
 readlink
   
 read link permission. Allows the target of a
        symbolic link to be read by invoking the 
        readSymbolicLink method. 



The actions string is converted to lowercase before processing.

 Be careful when granting FilePermissions. Think about the implications of granting read and especially write access to various files and directories. The "<<ALL FILES>>" permission with write action is especially dangerous. This grants permission to write to the entire file system. One thing this effectively allows is replacement of the system binary, including the JVM runtime environment. 
Please note: Code can always read a file from the same
directory it's in (or a subdirectory of that directory); it does not
need explicit permission to do so.

Author:Marianne Mueller, Roland Schemers
See Also:
Since:1.2
@serialexclude
/**
 * This class represents access to a file or directory.  A FilePermission consists
 * of a pathname and a set of actions valid for that pathname.
 * <P>
 * Pathname is the pathname of the file or directory granted the specified
 * actions. A pathname that ends in "/*" (where "/" is
 * the file separator character, <code>File.separatorChar</code>) indicates
 * all the files and directories contained in that directory. A pathname
 * that ends with "/-" indicates (recursively) all files
 * and subdirectories contained in that directory. Such a pathname is called
 * a wildcard pathname. Otherwise, it's a simple pathname.
 * <P>
 * A pathname consisting of the special token {@literal "<<ALL FILES>>"}
 * matches <b>any</b> file.
 * <P>
 * Note: A pathname consisting of a single "*" indicates all the files
 * in the current directory, while a pathname consisting of a single "-"
 * indicates all the files in the current directory and
 * (recursively) all files and subdirectories contained in the current
 * directory.
 * <P>
 * The actions to be granted are passed to the constructor in a string containing
 * a list of one or more comma-separated keywords. The possible keywords are
 * "read", "write", "execute", "delete", and "readlink". Their meaning is
 * defined as follows:
 *
 * <DL>
 *    <DT> read <DD> read permission
 *    <DT> write <DD> write permission
 *    <DT> execute
 *    <DD> execute permission. Allows <code>Runtime.exec</code> to
 *         be called. Corresponds to <code>SecurityManager.checkExec</code>.
 *    <DT> delete
 *    <DD> delete permission. Allows <code>File.delete</code> to
 *         be called. Corresponds to <code>SecurityManager.checkDelete</code>.
 *    <DT> readlink
 *    <DD> read link permission. Allows the target of a
 *         <a href="../nio/file/package-summary.html#links">symbolic link</a>
 *         to be read by invoking the {@link java.nio.file.Files#readSymbolicLink
 *         readSymbolicLink } method.
 * </DL>
 * <P>
 * The actions string is converted to lowercase before processing.
 * <P>
 * Be careful when granting FilePermissions. Think about the implications
 * of granting read and especially write access to various files and
 * directories. The {@literal "<<ALL FILES>>"} permission with write action is
 * especially dangerous. This grants permission to write to the entire
 * file system. One thing this effectively allows is replacement of the
 * system binary, including the JVM runtime environment.
 *
 * <p>Please note: Code can always read a file from the same
 * directory it's in (or a subdirectory of that directory); it does not
 * need explicit permission to do so.
 *
 * @see java.security.Permission
 * @see java.security.Permissions
 * @see java.security.PermissionCollection
 *
 *
 * @author Marianne Mueller
 * @author Roland Schemers
 * @since 1.2
 *
 * @serial exclude
 */

public final class FilePermission extends Permission implements Serializable {

    
Execute action.

/**
     * Execute action.
     */
    private final static int EXECUTE = 0x1;
    
Write action.

/**
     * Write action.
     */
    private final static int WRITE   = 0x2;
    
Read action.

/**
     * Read action.
     */
    private final static int READ    = 0x4;
    
Delete action.

/**
     * Delete action.
     */
    private final static int DELETE  = 0x8;
    
Read link action.

/**
     * Read link action.
     */
    private final static int READLINK    = 0x10;

    
All actions (read,write,execute,delete,readlink)

/**
     * All actions (read,write,execute,delete,readlink)
     */
    private final static int ALL     = READ|WRITE|EXECUTE|DELETE|READLINK;
    
No actions.

/**
     * No actions.
     */
    private final static int NONE    = 0x0;

    // the actions mask
    private transient int mask;

    // does path indicate a directory? (wildcard or recursive)
    private transient boolean directory;

    // is it a recursive directory specification?
    private transient boolean recursive;

    
the actions string.

@serial
/**
     * the actions string.
     *
     * @serial
     */
    private String actions; // Left null as long as possible, then
                            // created and re-used in the getAction function.

    // canonicalized dir path. In the case of
    // directories, it is the name "/blah/*" or "/blah/-" without
    // the last character (the "*" or "-").

    private transient String cpath;

    private transient boolean allFiles; // whether this is <<ALL FILES>>
    private transient boolean invalid;  // whether input path is invalid

    // static Strings used by init(int mask)
    private static final char RECURSIVE_CHAR = '-';
    private static final char WILD_CHAR = '*';

/*
    public String toString()
    {
        StringBuffer sb = new StringBuffer();
        sb.append("***\n");
        sb.append("cpath = "+cpath+"\n");
        sb.append("mask = "+mask+"\n");
        sb.append("actions = "+getActions()+"\n");
        sb.append("directory = "+directory+"\n");
        sb.append("recursive = "+recursive+"\n");
        sb.append("***\n");
        return sb.toString();
    }
*/

    private static final long serialVersionUID = 7930732926638008763L;

    
Always use the internal default file system, in case it was modified
with java.nio.file.spi.DefaultFileSystemProvider.

/**
     * Always use the internal default file system, in case it was modified
     * with java.nio.file.spi.DefaultFileSystemProvider.
     */
    private static final java.nio.file.FileSystem builtInFS =
            DefaultFileSystemProvider.create()
                    .getFileSystem(URI.create("file:///"));

    
initialize a FilePermission object. Common to all constructors.
Also called during de-serialization.

Params:
  • mask – the actions mask to use.
/**
     * initialize a FilePermission object. Common to all constructors.
     * Also called during de-serialization.
     *
     * @param mask the actions mask to use.
     *
     */
    private void init(int mask) {
        if ((mask & ALL) != mask)
                throw new IllegalArgumentException("invalid actions mask");

        if (mask == NONE)
                throw new IllegalArgumentException("invalid actions mask");

        if ((cpath = getName()) == null)
                throw new NullPointerException("name can't be null");

        this.mask = mask;

        if (cpath.equals("<<ALL FILES>>")) {
            allFiles = true;
            directory = true;
            recursive = true;
            cpath = "";
            return;
        }

        // Validate path by platform's default file system
        // Note: this check does not apply during FilePermission
        // class initialization.
        if (builtInFS != null) {
            try {
                String name = cpath.endsWith("*") ?
                        cpath.substring(0, cpath.length() - 1) + "-" : cpath;
                builtInFS.getPath(new File(name).getPath());
            } catch (InvalidPathException ipe) {
                invalid = true;
                return;
            }
        }

        // store only the canonical cpath if possible
        cpath = AccessController.doPrivileged(new PrivilegedAction<String>() {
            public String run() {
                try {
                    String path = cpath;
                    if (cpath.endsWith("*")) {
                        // call getCanonicalPath with a path with wildcard character
                        // replaced to avoid calling it with paths that are
                        // intended to match all entries in a directory
                        path = path.substring(0, path.length()-1) + "-";
                        path = new File(path).getCanonicalPath();
                        return path.substring(0, path.length()-1) + "*";
                    } else {
                        return new File(path).getCanonicalPath();
                    }
                } catch (IOException ioe) {
                    return cpath;
                }
            }
        });

        int len = cpath.length();
        char last = ((len > 0) ? cpath.charAt(len - 1) : 0);

        if (last == RECURSIVE_CHAR &&
            cpath.charAt(len - 2) == File.separatorChar) {
            directory = true;
            recursive = true;
            cpath = cpath.substring(0, --len);
        } else if (last == WILD_CHAR &&
            cpath.charAt(len - 2) == File.separatorChar) {
            directory = true;
            //recursive = false;
            cpath = cpath.substring(0, --len);
        } else {
            // overkill since they are initialized to false, but
            // commented out here to remind us...
            //directory = false;
            //recursive = false;
        }

        // XXX: at this point the path should be absolute. die if it isn't?
    }

    
Creates a new FilePermission object with the specified actions.
path is the pathname of a file or directory, and actions
contains a comma-separated list of the desired actions granted on the
file or directory. Possible actions are
"read", "write", "execute", "delete", and "readlink".

A pathname that ends in "/*" (where "/" is
the file separator character, File.separatorChar)
indicates all the files and directories contained in that directory.
A pathname that ends with "/-" indicates (recursively) all files and
subdirectories contained in that directory. The special pathname
"<<ALL FILES>>" matches any file.

A pathname consisting of a single "*" indicates all the files
in the current directory, while a pathname consisting of a single "-"
indicates all the files in the current directory and
(recursively) all files and subdirectories contained in the current
directory.

A pathname containing an empty string represents an empty path.

Params:
  • path – the pathname of the file/directory.
  • actions – the action string.
Throws:
/**
     * Creates a new FilePermission object with the specified actions.
     * <i>path</i> is the pathname of a file or directory, and <i>actions</i>
     * contains a comma-separated list of the desired actions granted on the
     * file or directory. Possible actions are
     * "read", "write", "execute", "delete", and "readlink".
     *
     * <p>A pathname that ends in "/*" (where "/" is
     * the file separator character, <code>File.separatorChar</code>)
     * indicates all the files and directories contained in that directory.
     * A pathname that ends with "/-" indicates (recursively) all files and
     * subdirectories contained in that directory. The special pathname
     * "&lt;&lt;ALL FILES&gt;&gt;" matches any file.
     *
     * <p>A pathname consisting of a single "*" indicates all the files
     * in the current directory, while a pathname consisting of a single "-"
     * indicates all the files in the current directory and
     * (recursively) all files and subdirectories contained in the current
     * directory.
     *
     * <p>A pathname containing an empty string represents an empty path.
     *
     * @param path the pathname of the file/directory.
     * @param actions the action string.
     *
     * @throws IllegalArgumentException
     *          If actions is <code>null</code>, empty or contains an action
     *          other than the specified possible actions.
     */
    public FilePermission(String path, String actions) {
        super(path);
        init(getMask(actions));
    }

    
Creates a new FilePermission object using an action mask.
More efficient than the FilePermission(String, String) constructor.
Can be used from within
code that needs to create a FilePermission object to pass into the
implies method.

Params:
  • path – the pathname of the file/directory.
  • mask – the action mask to use.
/**
     * Creates a new FilePermission object using an action mask.
     * More efficient than the FilePermission(String, String) constructor.
     * Can be used from within
     * code that needs to create a FilePermission object to pass into the
     * <code>implies</code> method.
     *
     * @param path the pathname of the file/directory.
     * @param mask the action mask to use.
     */

    // package private for use by the FilePermissionCollection add method
    FilePermission(String path, int mask) {
        super(path);
        init(mask);
    }

    
Checks if this FilePermission object "implies" the specified permission.


More specifically, this method returns true if:

    

  •  p is an instanceof FilePermission,

  •  p's actions are a proper subset of this
object's actions, and

  •  p's pathname is implied by this object's
     pathname. For example, "/tmp/*" implies "/tmp/foo", since
     "/tmp/*" encompasses all files in the "/tmp" directory,
     including the one named "foo".




Precisely, a simple pathname implies another simple pathname
if and only if they are equal. A simple pathname never implies
a wildcard pathname. A wildcard pathname implies another wildcard
pathname if and only if all simple pathnames implied by the latter
are implied by the former. A wildcard pathname implies a simple
pathname if and only if

    
    
  • if the wildcard flag is "*", the simple pathname's path
    must be right inside the wildcard pathname's path.
    
  • if the wildcard flag is "-", the simple pathname's path
    must be recursively inside the wildcard pathname's path.



 "<<ALL FILES>>" implies every other pathname. No pathname, except for "<<ALL FILES>>" itself, implies "<<ALL FILES>>". 
Params:
  • p – the permission to check against.
Returns:true if the specified permission is not
                 null and is implied by this object,
                 false otherwise.
/**
     * Checks if this FilePermission object "implies" the specified permission.
     * <P>
     * More specifically, this method returns true if:
     * <ul>
     * <li> <i>p</i> is an instanceof FilePermission,
     * <li> <i>p</i>'s actions are a proper subset of this
     * object's actions, and
     * <li> <i>p</i>'s pathname is implied by this object's
     *      pathname. For example, "/tmp/*" implies "/tmp/foo", since
     *      "/tmp/*" encompasses all files in the "/tmp" directory,
     *      including the one named "foo".
     * </ul>
     * <P>
     * Precisely, a simple pathname implies another simple pathname
     * if and only if they are equal. A simple pathname never implies
     * a wildcard pathname. A wildcard pathname implies another wildcard
     * pathname if and only if all simple pathnames implied by the latter
     * are implied by the former. A wildcard pathname implies a simple
     * pathname if and only if
     * <ul>
     *     <li>if the wildcard flag is "*", the simple pathname's path
     *     must be right inside the wildcard pathname's path.
     *     <li>if the wildcard flag is "-", the simple pathname's path
     *     must be recursively inside the wildcard pathname's path.
     * </ul>
     * <P>
     * {@literal "<<ALL FILES>>"} implies every other pathname. No pathname,
     * except for {@literal "<<ALL FILES>>"} itself, implies
     * {@literal "<<ALL FILES>>"}.
     *
     * @param p the permission to check against.
     *
     * @return <code>true</code> if the specified permission is not
     *                  <code>null</code> and is implied by this object,
     *                  <code>false</code> otherwise.
     */
    public boolean implies(Permission p) {
        if (!(p instanceof FilePermission))
            return false;

        FilePermission that = (FilePermission) p;

        // we get the effective mask. i.e., the "and" of this and that.
        // They must be equal to that.mask for implies to return true.

        return ((this.mask & that.mask) == that.mask) && impliesIgnoreMask(that);
    }

    
Checks if the Permission's actions are a proper subset of the
this object's actions. Returns the effective mask iff the
this FilePermission's path also implies that FilePermission's path.

Params:
  • that – the FilePermission to check against.
Returns:the effective mask
/**
     * Checks if the Permission's actions are a proper subset of the
     * this object's actions. Returns the effective mask iff the
     * this FilePermission's path also implies that FilePermission's path.
     *
     * @param that the FilePermission to check against.
     * @return the effective mask
     */
    boolean impliesIgnoreMask(FilePermission that) {
        if (this == that) {
            return true;
        }
        if (allFiles) {
            return true;
        }
        if (this.invalid || that.invalid) {
            return false;
        }
        if (that.allFiles) {
            return false;
        }
        if (this.directory) {
            if (this.recursive) {
                // make sure that.path is longer then path so
                // something like /foo/- does not imply /foo
                if (that.directory) {
                    return (that.cpath.length() >= this.cpath.length()) &&
                            that.cpath.startsWith(this.cpath);
                }  else {
                    return ((that.cpath.length() > this.cpath.length()) &&
                        that.cpath.startsWith(this.cpath));
                }
            } else {
                if (that.directory) {
                    // if the permission passed in is a directory
                    // specification, make sure that a non-recursive
                    // permission (i.e., this object) can't imply a recursive
                    // permission.
                    if (that.recursive)
                        return false;
                    else
                        return (this.cpath.equals(that.cpath));
                } else {
                    int last = that.cpath.lastIndexOf(File.separatorChar);
                    if (last == -1)
                        return false;
                    else {
                        // this.cpath.equals(that.cpath.substring(0, last+1));
                        // Use regionMatches to avoid creating new string
                        return (this.cpath.length() == (last + 1)) &&
                            this.cpath.regionMatches(0, that.cpath, 0, last+1);
                    }
                }
            }
        } else if (that.directory) {
            // if this is NOT recursive/wildcarded,
            // do not let it imply a recursive/wildcarded permission
            return false;
        } else {
            return (this.cpath.equals(that.cpath));
        }
    }

    
Checks two FilePermission objects for equality. Checks that obj is
a FilePermission, and has the same pathname and actions as this object.

Params:
  • obj – the object we are testing for equality with this object.
Implementation Note:More specifically, two pathnames are the same if and only if they have the same wildcard flag and their npath are equal. Or they are both "<<ALL FILES>>".
Returns:true if obj is a FilePermission, and has the same
         pathname and actions as this FilePermission object,
         false otherwise.
/**
     * Checks two FilePermission objects for equality. Checks that <i>obj</i> is
     * a FilePermission, and has the same pathname and actions as this object.
     *
     * @implNote More specifically, two pathnames are the same if and only if
     * they have the same wildcard flag and their
     * {@code npath} are equal. Or they are both {@literal "<<ALL FILES>>"}.
     *
     * @param obj the object we are testing for equality with this object.
     * @return <code>true</code> if obj is a FilePermission, and has the same
     *          pathname and actions as this FilePermission object,
     *          <code>false</code> otherwise.
     */
    public boolean equals(Object obj) {
        if (obj == this)
            return true;

        if (! (obj instanceof FilePermission))
            return false;

        FilePermission that = (FilePermission) obj;

        if (this.invalid || that.invalid) {
            return false;
        }
        return (this.mask == that.mask) &&
            (this.allFiles == that.allFiles) &&
            this.cpath.equals(that.cpath) &&
            (this.directory == that.directory) &&
            (this.recursive == that.recursive);
    }

    
Returns the hash code value for this object.

Returns:a hash code value for this object.
/**
     * Returns the hash code value for this object.
     *
     * @return a hash code value for this object.
     */
    public int hashCode() {
        return 0;
    }

    
Converts an actions String to an actions mask.

Params:
  • actions – the action string.
Returns:the actions mask.
/**
     * Converts an actions String to an actions mask.
     *
     * @param actions the action string.
     * @return the actions mask.
     */
    private static int getMask(String actions) {
        int mask = NONE;

        // Null action valid?
        if (actions == null) {
            return mask;
        }

        // Use object identity comparison against known-interned strings for
        // performance benefit (these values are used heavily within the JDK).
        if (actions == SecurityConstants.FILE_READ_ACTION) {
            return READ;
        } else if (actions == SecurityConstants.FILE_WRITE_ACTION) {
            return WRITE;
        } else if (actions == SecurityConstants.FILE_EXECUTE_ACTION) {
            return EXECUTE;
        } else if (actions == SecurityConstants.FILE_DELETE_ACTION) {
            return DELETE;
        } else if (actions == SecurityConstants.FILE_READLINK_ACTION) {
            return READLINK;
        }

        char[] a = actions.toCharArray();

        int i = a.length - 1;
        if (i < 0)
            return mask;

        while (i != -1) {
            char c;

            // skip whitespace
            while ((i!=-1) && ((c = a[i]) == ' ' ||
                               c == '\r' ||
                               c == '\n' ||
                               c == '\f' ||
                               c == '\t'))
                i--;

            // check for the known strings
            int matchlen;

            if (i >= 3 && (a[i-3] == 'r' || a[i-3] == 'R') &&
                          (a[i-2] == 'e' || a[i-2] == 'E') &&
                          (a[i-1] == 'a' || a[i-1] == 'A') &&
                          (a[i] == 'd' || a[i] == 'D'))
            {
                matchlen = 4;
                mask |= READ;

            } else if (i >= 4 && (a[i-4] == 'w' || a[i-4] == 'W') &&
                                 (a[i-3] == 'r' || a[i-3] == 'R') &&
                                 (a[i-2] == 'i' || a[i-2] == 'I') &&
                                 (a[i-1] == 't' || a[i-1] == 'T') &&
                                 (a[i] == 'e' || a[i] == 'E'))
            {
                matchlen = 5;
                mask |= WRITE;

            } else if (i >= 6 && (a[i-6] == 'e' || a[i-6] == 'E') &&
                                 (a[i-5] == 'x' || a[i-5] == 'X') &&
                                 (a[i-4] == 'e' || a[i-4] == 'E') &&
                                 (a[i-3] == 'c' || a[i-3] == 'C') &&
                                 (a[i-2] == 'u' || a[i-2] == 'U') &&
                                 (a[i-1] == 't' || a[i-1] == 'T') &&
                                 (a[i] == 'e' || a[i] == 'E'))
            {
                matchlen = 7;
                mask |= EXECUTE;

            } else if (i >= 5 && (a[i-5] == 'd' || a[i-5] == 'D') &&
                                 (a[i-4] == 'e' || a[i-4] == 'E') &&
                                 (a[i-3] == 'l' || a[i-3] == 'L') &&
                                 (a[i-2] == 'e' || a[i-2] == 'E') &&
                                 (a[i-1] == 't' || a[i-1] == 'T') &&
                                 (a[i] == 'e' || a[i] == 'E'))
            {
                matchlen = 6;
                mask |= DELETE;

            } else if (i >= 7 && (a[i-7] == 'r' || a[i-7] == 'R') &&
                                 (a[i-6] == 'e' || a[i-6] == 'E') &&
                                 (a[i-5] == 'a' || a[i-5] == 'A') &&
                                 (a[i-4] == 'd' || a[i-4] == 'D') &&
                                 (a[i-3] == 'l' || a[i-3] == 'L') &&
                                 (a[i-2] == 'i' || a[i-2] == 'I') &&
                                 (a[i-1] == 'n' || a[i-1] == 'N') &&
                                 (a[i] == 'k' || a[i] == 'K'))
            {
                matchlen = 8;
                mask |= READLINK;

            } else {
                // parse error
                throw new IllegalArgumentException(
                        "invalid permission: " + actions);
            }

            // make sure we didn't just match the tail of a word
            // like "ackbarfaccept".  Also, skip to the comma.
            boolean seencomma = false;
            while (i >= matchlen && !seencomma) {
                switch(a[i-matchlen]) {
                case ',':
                    seencomma = true;
                    break;
                case ' ': case '\r': case '\n':
                case '\f': case '\t':
                    break;
                default:
                    throw new IllegalArgumentException(
                            "invalid permission: " + actions);
                }
                i--;
            }

            // point i at the location of the comma minus one (or -1).
            i -= matchlen;
        }

        return mask;
    }

    
Return the current action mask. Used by the FilePermissionCollection.

Returns:the actions mask.
/**
     * Return the current action mask. Used by the FilePermissionCollection.
     *
     * @return the actions mask.
     */
    int getMask() {
        return mask;
    }

    
Return the canonical string representation of the actions.
Always returns present actions in the following order:
read, write, execute, delete, readlink.

Returns:the canonical string representation of the actions.
/**
     * Return the canonical string representation of the actions.
     * Always returns present actions in the following order:
     * read, write, execute, delete, readlink.
     *
     * @return the canonical string representation of the actions.
     */
    private static String getActions(int mask) {
        StringBuilder sb = new StringBuilder();
        boolean comma = false;

        if ((mask & READ) == READ) {
            comma = true;
            sb.append("read");
        }

        if ((mask & WRITE) == WRITE) {
            if (comma) sb.append(',');
            else comma = true;
            sb.append("write");
        }

        if ((mask & EXECUTE) == EXECUTE) {
            if (comma) sb.append(',');
            else comma = true;
            sb.append("execute");
        }

        if ((mask & DELETE) == DELETE) {
            if (comma) sb.append(',');
            else comma = true;
            sb.append("delete");
        }

        if ((mask & READLINK) == READLINK) {
            if (comma) sb.append(',');
            else comma = true;
            sb.append("readlink");
        }

        return sb.toString();
    }

    
Returns the "canonical string representation" of the actions.
That is, this method always returns present actions in the following order:
read, write, execute, delete, readlink. For example, if this FilePermission
object allows both write and read actions, a call to getActions
will return the string "read,write".

Returns:the canonical string representation of the actions.
/**
     * Returns the "canonical string representation" of the actions.
     * That is, this method always returns present actions in the following order:
     * read, write, execute, delete, readlink. For example, if this FilePermission
     * object allows both write and read actions, a call to <code>getActions</code>
     * will return the string "read,write".
     *
     * @return the canonical string representation of the actions.
     */
    public String getActions() {
        if (actions == null)
            actions = getActions(this.mask);

        return actions;
    }

    
Returns a new PermissionCollection object for storing FilePermission
objects.


FilePermission objects must be stored in a manner that allows them
to be inserted into the collection in any order, but that also enables the
PermissionCollection implies
method to be implemented in an efficient (and consistent) manner.

For example, if you have two FilePermissions:

    

  1.   "/tmp/-", "read"

  2.   "/tmp/scratch/foo", "write"



and you are calling the implies method with the FilePermission:

  "/tmp/scratch/foo", "read,write",


then the implies function must
take into account both the "/tmp/-" and "/tmp/scratch/foo"
permissions, so the effective permission is "read,write",
and implies returns true. The "implies" semantics for
FilePermissions are handled properly by the PermissionCollection object
returned by this newPermissionCollection method.

Returns:a new PermissionCollection object suitable for storing
FilePermissions.
/**
     * Returns a new PermissionCollection object for storing FilePermission
     * objects.
     * <p>
     * FilePermission objects must be stored in a manner that allows them
     * to be inserted into the collection in any order, but that also enables the
     * PermissionCollection <code>implies</code>
     * method to be implemented in an efficient (and consistent) manner.
     *
     * <p>For example, if you have two FilePermissions:
     * <OL>
     * <LI>  <code>"/tmp/-", "read"</code>
     * <LI>  <code>"/tmp/scratch/foo", "write"</code>
     * </OL>
     *
     * <p>and you are calling the <code>implies</code> method with the FilePermission:
     *
     * <pre>
     *   "/tmp/scratch/foo", "read,write",
     * </pre>
     *
     * then the <code>implies</code> function must
     * take into account both the "/tmp/-" and "/tmp/scratch/foo"
     * permissions, so the effective permission is "read,write",
     * and <code>implies</code> returns true. The "implies" semantics for
     * FilePermissions are handled properly by the PermissionCollection object
     * returned by this <code>newPermissionCollection</code> method.
     *
     * @return a new PermissionCollection object suitable for storing
     * FilePermissions.
     */
    public PermissionCollection newPermissionCollection() {
        return new FilePermissionCollection();
    }

    
WriteObject is called to save the state of the FilePermission
to a stream. The actions are serialized, and the superclass
takes care of the name.

/**
     * WriteObject is called to save the state of the FilePermission
     * to a stream. The actions are serialized, and the superclass
     * takes care of the name.
     */
    private void writeObject(ObjectOutputStream s)
        throws IOException
    {
        // Write out the actions. The superclass takes care of the name
        // call getActions to make sure actions field is initialized
        if (actions == null)
            getActions();
        s.defaultWriteObject();
    }

    
readObject is called to restore the state of the FilePermission from
a stream.

/**
     * readObject is called to restore the state of the FilePermission from
     * a stream.
     */
    private void readObject(ObjectInputStream s)
         throws IOException, ClassNotFoundException
    {
        // Read in the actions, then restore everything else by calling init.
        s.defaultReadObject();
        init(getMask(actions));
    }
}


A FilePermissionCollection stores a set of FilePermission permissions.
FilePermission objects
must be stored in a manner that allows them to be inserted in any
order, but enable the implies function to evaluate the implies
method.
For example, if you have two FilePermissions:

    

  1.  "/tmp/-", "read"

  2.  "/tmp/scratch/foo", "write"


And you are calling the implies function with the FilePermission:
"/tmp/scratch/foo", "read,write", then the implies function must
take into account both the /tmp/- and /tmp/scratch/foo
permissions, so the effective permission is "read,write".

Author:Marianne Mueller, Roland Schemers
See Also:
@serialinclude
/**
 * A FilePermissionCollection stores a set of FilePermission permissions.
 * FilePermission objects
 * must be stored in a manner that allows them to be inserted in any
 * order, but enable the implies function to evaluate the implies
 * method.
 * For example, if you have two FilePermissions:
 * <OL>
 * <LI> "/tmp/-", "read"
 * <LI> "/tmp/scratch/foo", "write"
 * </OL>
 * And you are calling the implies function with the FilePermission:
 * "/tmp/scratch/foo", "read,write", then the implies function must
 * take into account both the /tmp/- and /tmp/scratch/foo
 * permissions, so the effective permission is "read,write".
 *
 * @see java.security.Permission
 * @see java.security.Permissions
 * @see java.security.PermissionCollection
 *
 *
 * @author Marianne Mueller
 * @author Roland Schemers
 *
 * @serial include
 *
 */

final class FilePermissionCollection extends PermissionCollection
    implements Serializable
{
    // Not serialized; see serialization section at end of class
    private transient List<Permission> perms;

    
Create an empty FilePermissionCollection object.

/**
     * Create an empty FilePermissionCollection object.
     */
    public FilePermissionCollection() {
        perms = new ArrayList<>();
    }

    
Adds a permission to the FilePermissionCollection. The key for the hash is
permission.path.

Params:
  • permission – the Permission object to add.
Throws:
/**
     * Adds a permission to the FilePermissionCollection. The key for the hash is
     * permission.path.
     *
     * @param permission the Permission object to add.
     *
     * @exception IllegalArgumentException - if the permission is not a
     *                                       FilePermission
     *
     * @exception SecurityException - if this FilePermissionCollection object
     *                                has been marked readonly
     */
    public void add(Permission permission) {
        if (! (permission instanceof FilePermission))
            throw new IllegalArgumentException("invalid permission: "+
                                               permission);
        if (isReadOnly())
            throw new SecurityException(
                "attempt to add a Permission to a readonly PermissionCollection");

        synchronized (this) {
            perms.add(permission);
        }
    }

    
Check and see if this set of permissions implies the permissions
expressed in "permission".

Params:
  • permission – the Permission object to compare
Returns:true if "permission" is a proper subset of a permission in
the set, false if not.
/**
     * Check and see if this set of permissions implies the permissions
     * expressed in "permission".
     *
     * @param permission the Permission object to compare
     *
     * @return true if "permission" is a proper subset of a permission in
     * the set, false if not.
     */
    public boolean implies(Permission permission) {
        if (! (permission instanceof FilePermission))
            return false;

        FilePermission fp = (FilePermission) permission;

        int desired = fp.getMask();
        int effective = 0;
        int needed = desired;

        synchronized (this) {
            int len = perms.size();
            for (int i = 0; i < len; i++) {
                FilePermission x = (FilePermission) perms.get(i);
                if (((needed & x.getMask()) != 0) && x.impliesIgnoreMask(fp)) {
                    effective |=  x.getMask();
                    if ((effective & desired) == desired)
                        return true;
                    needed = (desired ^ effective);
                }
            }
        }
        return false;
    }

    
Returns an enumeration of all the FilePermission objects in the
container.

Returns:an enumeration of all the FilePermission objects.
/**
     * Returns an enumeration of all the FilePermission objects in the
     * container.
     *
     * @return an enumeration of all the FilePermission objects.
     */
    public Enumeration<Permission> elements() {
        // Convert Iterator into Enumeration
        synchronized (this) {
            return Collections.enumeration(perms);
        }
    }

    private static final long serialVersionUID = 2202956749081564585L;

    // Need to maintain serialization interoperability with earlier releases,
    // which had the serializable field:
    //    private Vector permissions;

    
@serialFieldpermissions java.util.Vector
    A list of FilePermission objects.
/**
     * @serialField permissions java.util.Vector
     *     A list of FilePermission objects.
     */
    private static final ObjectStreamField[] serialPersistentFields = {
        new ObjectStreamField("permissions", Vector.class),
    };

    
@serialData"permissions" field (a Vector containing the FilePermissions).
/**
     * @serialData "permissions" field (a Vector containing the FilePermissions).
     */
    /*
     * Writes the contents of the perms field out as a Vector for
     * serialization compatibility with earlier releases.
     */
    private void writeObject(ObjectOutputStream out) throws IOException {
        // Don't call out.defaultWriteObject()

        // Write out Vector
        Vector<Permission> permissions = new Vector<>(perms.size());
        synchronized (this) {
            permissions.addAll(perms);
        }

        ObjectOutputStream.PutField pfields = out.putFields();
        pfields.put("permissions", permissions);
        out.writeFields();
    }

    /*
     * Reads in a Vector of FilePermissions and saves them in the perms field.
     */
    private void readObject(ObjectInputStream in)
        throws IOException, ClassNotFoundException
    {
        // Don't call defaultReadObject()

        // Read in serialized fields
        ObjectInputStream.GetField gfields = in.readFields();

        // Get the one we want
        @SuppressWarnings("unchecked")
        Vector<Permission> permissions = (Vector<Permission>)gfields.get("permissions", null);
        perms = new ArrayList<>(permissions.size());
        for (Permission perm : permissions) {
            perms.add(perm);
        }
    }
}