Re: [cp-patches] Patch: Opening RandomAccessFiles requires excessive permission

[David Daney]

Gary Benson wrote:
> Hi all,
>
> Opening a java.io.RandomAccessFile in read-only mode with a security
> manager in force requires the permission to write file descriptors.
> The attached patch fixes.  Anyone mind if I commit?
>
> Cheers,
> Gary
>
>
> ------------------------------------------------------------------------
>
> Index: ChangeLog
> ===================================================================
> RCS file: /cvsroot/classpath/classpath/ChangeLog,v
> retrieving revision 1.5764
> diff -u -r1.5764 ChangeLog
> --- ChangeLog   5 Dec 2005 13:25:00 -0000       1.5764
> +++ ChangeLog   5 Dec 2005 14:36:19 -0000
> @@ -1,3 +1,9 @@
> +2005-11-18  Gary Benson  <address@hidden>
> +
> +       * java/io/RandomAccessFile.java (RandomAccessFile): Don't create
> +       DataOutputStream for read-only files to avoid unnecessary security
> +       manager check.
> +
>  2005-12-05  Mark Wielaard  <address@hidden>
>  
>  	Fixes bug classpath/25257
> Index: java/io/RandomAccessFile.java
> ===================================================================
> RCS file: /cvsroot/classpath/classpath/java/io/RandomAccessFile.java,v
> retrieving revision 1.47
> diff -u -r1.47 RandomAccessFile.java
> --- java/io/RandomAccessFile.java       2 Jul 2005 20:32:38 -0000       1.47
> +++ java/io/RandomAccessFile.java       5 Dec 2005 14:36:19 -0000
> @@ -124,7 +124,10 @@
>  
>      ch = FileChannelImpl.create(file, fdmode);
>      fd = new FileDescriptor(ch);
> -    out = new DataOutputStream (new FileOutputStream (fd));
> +    if ((fdmode & FileChannelImpl.WRITE) != 0)
> +      out = new DataOutputStream (new FileOutputStream (fd));
> +    else
> +      out = null;
>      in = new DataInputStream (new FileInputStream (fd));
>    }
>  
> @@ -766,6 +769,9 @@
>     */
>    public void write (int oneByte) throws IOException
>    {
> +    if (out == null)
> +      throw new IOException("Bad file descriptor");
> +

The real error is that the file was opened read-only.  A message saying 
"Bad file descriptor" does not convey that information.  If the only 
reason that out can be null is that it was opened read-only, then I 
think all the exception messages should reflect that.

David Daney.