? tools/man2tcl
? unix/linux-ix86
? unix/buffer.tcl
Index: ChangeLog
===================================================================
RCS file: /cvsroot/tcl/tcl/ChangeLog,v
retrieving revision 1.491
diff -u -r1.491 ChangeLog
--- ChangeLog	2001/07/06 22:03:11	1.491
+++ ChangeLog	2001/07/17 17:46:01
@@ -1,3 +1,13 @@
+2001-07-17  Andreas Kupries <andreas_kupries@users.sourceforge.net>
+
+	* generic/tclIO.c (GetInput): Fixed [SF #427196]. Memory was
+	  overwritten because a buffer was used after a change of the
+	  requested buffersize together with that requested buffersize and
+	  not its actual size, which was smaller. Note that the continous
+	  reuse of the smaller buffer negatively impacts performance. The
+	  system never allocates a buffer with the newly requested bigger
+	  buffersize.
+
 2001-07-06  Mo DeJong  <mdejong@redhat.com>
 
 	* win/configure: Regen.
Index: generic/tclIO.c
===================================================================
RCS file: /cvsroot/tcl/tcl/generic/tclIO.c,v
retrieving revision 1.30
diff -u -r1.30 tclIO.c
--- generic/tclIO.c	2001/05/19 16:59:04	1.30
+++ generic/tclIO.c	2001/07/17 17:46:01
@@ -4999,7 +4999,21 @@
 	}
         bufPtr->nextPtr = (ChannelBuffer *) NULL;
 
-        toRead = statePtr->bufSize;
+	/* SF #427196: Use the actual size of the buffer to determine
+	 * the number of bytes to read from the channel and not the
+	 * size for new buffers. They can be different if the
+	 * buffersize was changed between reads.
+	 *
+	 * Note: This affects performance negatively if the buffersize
+	 * was extended but this small buffer is reused for all
+	 * subsequent reads. The system never uses buffers with the
+	 * requested bigger size in that case. An adjunct patch could
+	 * try and delete all unused buffers it encounters and which
+	 * are smaller than the formally requested buffersize.
+	 */
+
+	toRead = bufPtr->bufLength - bufPtr->nextAdded;
+
         if (statePtr->inQueueTail == NULL) {
             statePtr->inQueueHead = bufPtr;
         } else {