JDK8/Java8源码在线阅读
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* accompanied this code).
*
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*
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package java.io;
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.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.
* <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. A pathname consisting of
* the special token "<<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 "<<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.
*/
private final static int EXECUTE = 0x1;
/**
* Write action.
*/
private final static int WRITE = 0x2;
/**
* Read action.
*/
private final static int READ = 0x4;
/**
* Delete action.
*/
private final static int DELETE = 0x8;
/**
* Read link action.
*/
private final static int READLINK = 0x10;
/**
* All actions (read,write,execute,delete,readlink)
*/
private final static int ALL = READ|WRITE|EXECUTE|DELETE|READLINK;
/**
* 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
*/
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;
// 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;
/**
* 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>>")) {
directory = true;
recursive = true;
cpath = "";
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.
* <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
* "<<ALL FILES>>" 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
* <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.
* <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>
*
* @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.
*
* @param that the FilePermission to check against.
* @return the effective mask
*/
boolean impliesIgnoreMask(FilePermission that) {
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 <i>obj</i> is
* a FilePermission, and has the same pathname and actions as this object.
*
* @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;
return (this.mask == that.mask) &&
this.cpath.equals(that.cpath) &&
(this.directory == that.directory) &&
(this.recursive == that.recursive);
}
/**
* 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.
*
* @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.
*
* @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.
*
* @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 <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.
* <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.
*/
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.
*/
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:
* <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.
*/
public FilePermissionCollection() {
perms = new ArrayList<>();
}
/**
* 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".
*
* @param permission the Permission object to compare
*
* @return true if "permission" is a proper subset of a permission in
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