bk commit into 5.0 tree (msvensson:1.2088) BUG#2845

[msvensson]

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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;