Bug#22943 syscall pruning in libmysql

 - Set the timeout values only where needed


sql/mysql_priv.h:
  Add new functions for setting read and write timeout on "net"
sql/mysqld.cc:
  - Move the setting of "read_timeout" to the value of "connect_timeout" to
    just before 'check_connection' which is the function where we want
    to use the different timeout
  - With the new functions to set timeout on "net", there is no need to
    specifically set the default wait_timeout on windows.
sql/net_serv.cc:
  Add new functions for setting read and write timeout of "net, when
  server is compiled not to use alarms it will set the write/read timeout
  directly on connection using 'vio_timeout'(using setsockopt if socket)
sql/repl_failsafe.cc:
  Put unused code within "#if NOT_USED"
sql/set_var.cc:
  Use 'net_set_*_timeout' when adjusting timeout value
  on the current connection
sql/slave.cc:
  The read timeout used when connecting to master server is set
  using 'mysql_options' in 'connect_to_master' function
sql/sql_parse.cc:
  - Set read and write timeout values to "connect_timeout" during
  connect phase
  - Use "read_timeout" value during sslaccept phase, since this is during
  connect phase it implies "connect-timeout"
  - Set read and write timeout value back to default after connect phase
  - Set "read_timeout" to "wait_timeout" while waiting for client.
sql/sql_repl.cc:
  Set "read_timeout" to "wait_timeout" while ask other mysqld to send file
sql-common/client.c:
  Call 'vio_timeout' to set up the read and write timeout's for the
  newly created connection. It only need to be done once at connect time.
vio/vio.c:
  Use 'vio_timeout' for setting timeout also on an SSL connection
  since they both use sockets
vio/viossl.c:
  Remove 'vio_ssl_timeout' function

1 files changed, 25 insertions, 12 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 07064113209..808e08e4b21 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -867,7 +867,7 @@ static int check_connection(THD *thd)
       return(ER_HANDSHAKE_ERROR);
     }
     DBUG_PRINT("info", ("IO layer change in progress..."));
-    if (sslaccept(ssl_acceptor_fd, net->vio, thd->variables.net_wait_timeout))
+    if (sslaccept(ssl_acceptor_fd, net->vio, net->read_timeout))
     {
       DBUG_PRINT("error", ("Failed to read user information (pkt_len= %lu)",
 			   pkt_len));
@@ -897,7 +897,6 @@ static int check_connection(THD *thd)
   if ((thd->client_capabilities & CLIENT_TRANSACTIONS) &&
       opt_using_transactions)
     net->return_status= &thd->server_status;
-  net->read_timeout=(uint) thd->variables.net_read_timeout;
 
   char *user= end;
   char *passwd= strend(user)+1;
@@ -1029,6 +1028,10 @@ pthread_handler_decl(handle_one_connection,arg)
     NET *net= &thd->net;
     thd->thread_stack= (char*) &thd;
 
+    /* Use "connect_timeout" value during connection phase */
+    net_set_read_timeout(net, connect_timeout);
+    net_set_write_timeout(net, connect_timeout);
+
     if ((error=check_connection(thd)))
     {						// Wrong permissions
       if (error > 0)
@@ -1058,6 +1061,11 @@ pthread_handler_decl(handle_one_connection,arg)
       if (thd->query_error)
 	thd->killed= 1;
     }
+
+    /* Connect completed, set read/write timeouts back to tdefault */
+    net_set_read_timeout(net, thd->variables.net_read_timeout);
+    net_set_write_timeout(net, thd->variables.net_write_timeout);
+
     while (!net->error && net->vio != 0 && !thd->killed)
     {
       if (do_command(thd))
@@ -1261,7 +1269,7 @@ err:
 #ifndef EMBEDDED_LIBRARY
 
 /*
-  Read one command from socket and execute it (query or simple command).
+  Read one command from connection and execute it (query or simple command).
   This function is called in loop from thread function.
   SYNOPSIS
     do_command()
@@ -1272,24 +1280,26 @@ err:
 
 bool do_command(THD *thd)
 {
-  char *packet;
-  uint old_timeout;
+  char *packet= 0;
   ulong packet_length;
-  NET *net;
+  NET *net= &thd->net;
   enum enum_server_command command;
   DBUG_ENTER("do_command");
 
-  net= &thd->net;
   /*
     indicator of uninitialized lex => normal flow of errors handling
     (see my_message_sql)
   */
   thd->lex->current_select= 0;
 
-  packet=0;
-  old_timeout=net->read_timeout;
-  // Wait max for 8 hours
-  net->read_timeout=(uint) thd->variables.net_wait_timeout;
+  /*
+    This thread will do a blocking read from the client which
+    will be interrupted when the next command is received from
+    the client, the connection is closed or "net_wait_timeout"
+    number of seconds has passed
+  */
+  net_set_read_timeout(net, thd->variables.net_wait_timeout);
+
   thd->clear_error();				// Clear error message
 
   net_new_transaction(net);
@@ -1318,7 +1328,10 @@ bool do_command(THD *thd)
 		       vio_description(net->vio), command,
 		       command_name[command]));
   }
-  net->read_timeout=old_timeout;		// restore it
+
+  /* Restore read timeout value */
+  net_set_read_timeout(net, thd->variables.net_read_timeout);
+
   /*
     packet_length contains length of data, as it was stored in packet
     header. In case of malformed header, packet_length can be zero.