[patch #2951] FileChannelImpl read/write(buff, offset, length) fails when buff.length == 0

[Stephen Crawley]

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 of the project: classpath.




/**************************************************************************/
[patch #2951] Full Item Snapshot:

URL: <http://savannah.gnu.org/patch/?func=detailitem&item_id=2951>
Project: classpath
Submitted by: Stephen Crawley
On: Mon 04/19/04 at 15:27

Category:  None
Priority:  5 - Normal
Resolution:  None
Assigned to:  None
Originator Email:  
Status:  Open


Summary:  FileChannelImpl read/write(buff, offset, length) fails when 
buff.length == 0

Original Submission:  The current native implementation of the 3 argument read 
and write methods of gnu.java.nio.channel.FileChannelImpl
throw an IOException with message "Unexpected JNI error"
when the buff argument has zero length.  This can happen
if an application tries to read or write an zero length
byte array with a File{Input,Output}Stream.  The problem
is that the native methods don't check the length arg
before making the JNI GetByteArrayElements call.  The
latter call then fails ...

The bugs are exercised by these Mauve testcases:
  gnu.testlet.java.io.FileOutputStream.write
  gnu.testlet.java.io.FileInputStream.read

The obvious fix is to have the native methods test for
length == 0 explicitly.  Suggested ChangeLog entries:

2004-04-20 Stephen Crawley <address@hidden>
  * native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c 
(Java_gnu_java_nio_channels_FileChannelImpl_read___3BII) :
  check for length == 0
  *  native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c 
(Java_gnu_java_nio_channels_FileChannelImpl_write___3BII)
  ditto









File Attachments
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Date: Mon 04/19/04 at 15:27  Name: diffs  Size: 1KB   By: crawley

http://savannah.gnu.org/patch/download.php?item_id=2951&amp;item_file_id=3124






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