From: Date: February 27 2006 3:37pm
Subject: bk commit into 5.0 tree (msvensson:1.2088) BUG#2845
List-Archive: http://lists.mysql.com/commits/3191
X-Bug: 2845
Message-Id: <20060227143730.B271C207825@localhost.localdomain>

Below is the list of changes that have just been committed into a local
5.0 repository of msvensson. When msvensson does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2088 06/02/27 15:37:23 msvensson@neptunus.(none) +1 -0
  BUG#2845 client fails to reconnect if using TCP/IP
   - Use 'poll' if available
   - Check that sd <= FD_SETSIZE if using 'select'
   - Handle case when 'net_data_is_ready' returns -1, ie. sd > FD_SETSIZE and 'select' is used 

  sql/net_serv.cc
    1.86 06/02/27 15:37:18 msvensson@neptunus.(none) +25 -4
    Use 'poll' in favor of 'select' if avaliable
    This is to avoid the limitation with 'select' only being able to handle fd's with numbers <= 1024 as default.
    If 'poll' is not available use 'select' but check that we are not having a number higher than FD_SETSIZE
    Handle the case when 'net_data_is_ready' can't check if there is data to read, since the sd number is too high

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	msvensson
# Host:	neptunus.(none)
# Root:	/home/msvensson/mysql/mysql-5.0

--- 1.85/sql/net_serv.cc	2006-02-16 12:02:34 +01:00
+++ 1.86/sql/net_serv.cc	2006-02-27 15:37:18 +01:00
@@ -208,23 +208,40 @@
   RETURN VALUES
     0	No data to read
     1	Data or EOF to read
+    -1  Don't know if data is ready or not
 */
 
-static my_bool net_data_is_ready(my_socket sd)
+static int net_data_is_ready(my_socket sd)
 {
+#ifdef HAVE_POLL
+  struct pollfd ufds;
+  int res;
+
+  ufds.fd= sd;
+  ufds.events= POLLIN | POLLPRI;
+  if (!(res= poll(&ufds, 1, 0)))
+    return 0;
+  if (res < 0 || !(ufds.revents & (POLLIN | POLLPRI)))
+    return 0;
+  return 1;
+#else
   fd_set sfds;
   struct timeval tv;
   int res;
 
+  if (sd >= FD_SETSIZE)
+    return -1;
+
   FD_ZERO(&sfds);
   FD_SET(sd, &sfds);
 
   tv.tv_sec= tv.tv_usec= 0;
 
   if ((res= select(sd+1, &sfds, NULL, NULL, &tv)) < 0)
-    return FALSE;
+    return 0;
   else
     return test(res ? FD_ISSET(sd, &sfds) : 0);
+#endif
 }
 
 
@@ -251,10 +268,10 @@
 
 void net_clear(NET *net)
 {
-  int count;
+  int count, ready;
   DBUG_ENTER("net_clear");
 #if !defined(EMBEDDED_LIBRARY)
-  while(net_data_is_ready(net->vio->sd))
+  while((ready= net_data_is_ready(net->vio->sd)) != 0)
   {
     /* The socket is ready */
     if ((count= vio_read(net->vio, (char*) (net->buff),
@@ -269,6 +286,10 @@
     }
     else
     {
+      /* No data to read and 'net_data_is_ready' returned "dont't know" */
+      if (ready == -1)
+        break;
+§
       DBUG_PRINT("info",("socket ready but only EOF to read - disconnected"));
       net->error= 2;
       break;