Re: [tpop3d-discuss]Corrupted TOP response with PIPELINING and tpop3d 1.5.3

[Chris Lightfoot]

On Wed, Feb 02, 2005 at 07:22:57PM +0100, Martin Blapp wrote:
> 
> Hi,
> 
> > i'm just trying to reproduce this locally -- can you
> > confirm that this scriptlet should show the problem:
> >
> > perl -MIO::Socket -e '$s = new IO::Socket::INET("localhost:9000");
>       $s->print("user USERNAME\r\n");
>       $s->getline();
>       $s->print("pass PASSWORD\r\n");
>       $s->getline(); $s->print("LIST\r\n");
>       for ($i = 1; $i < 2000; ++$i) {
>               $j=1 + $i%500;
>               $s->print("top $j 0\r\n");
>        }
>       $s->print("quit\r\n");
>       while (defined($_ = $s->getline())) { print $_; }'
> >
> > (replace USERNAME and PASSWORD as appropriate)
> 
> Why modulo $i%500  Just use $i ... its easier to debug afterwords.

oh -- the test mailbox only had about 500 mails in it.

> Yes it should trigger the problem.

ok... i can't reproduce it here, so it must be timing
dependent :(

that said there are definitely problems in the buffering
code. Can you try the following patch:

diff -u -r1.7 buffer.c
--- buffer.c    6 Nov 2003 01:19:27 -0000       1.7
+++ buffer.c    2 Feb 2005 18:24:22 -0000
@@ -208,10 +224,18 @@
 
 /* buffer_get_push_ptr BUFFER LEN
  * Return a pointer to part of BUFFER to which new data can be written. On
- * return, LEN indicates how many contiguous bytes may be written. */
+ * return, *LEN indicates how many contiguous bytes may be written. */
 char *buffer_get_push_ptr(buffer B, size_t *len) {
     assert(B);
-    *len = B->len - B->put;
+
+    if (B->put >= B->get) {
+        *len = B->len - B->put;
+        if (B->get == 0)
+            --*len;
+    } else if (B->put < B->get) {
+        *len = B->get - B->put - 1;
+    }
+    
     return B->buf + B->put;
 }
 

and tell me if it helps?

-- 
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