Added support for max_allowed_packet in option files read by mysql_option()

Extended max_allowed_packet for clients to 1G
Fixed bug in sending compressed rows >= 16M
Fix bug in skiping too long packets from clients.
Added checking of wrong command number sent by client.


include/mysql.h:
  Added max_allowed_packet as option parameter.
include/mysql_com.h:
  Added COM_END to be able to check for wrong commands.
libmysql/libmysql.c:
  Extended max_allowed_packet for clients to 1G
  Added support for max_allowed_packet in option files read by mysql_option()
mysys/my_compress.c:
  Debugging output
sql/net_pkg.cc:
  Fixed wrong handling of blobs >= 16M
sql/net_serv.cc:
  Changed MAX_THREE_BYTES -> MAX_PACKET_LENGTH
  More DEBUG output and more comments
  Fixed bug in sending compressed rows >= 16M
  Optimized sending of big packets (fewer memcpy and compress data in bigger blocks)
  Fix bug in skiping too long packets from clients.
  (old code didn't always work for big packets)
sql/sql_class.h:
  Changed type of variable
sql/sql_parse.cc:
  Added checking of wrong command number sent by client.
  Changed handling of too big packets to make code safer
tests/big_record.pl:
  E

1 files changed, 149 insertions, 84 deletions

diff --git a/sql/net_serv.cc b/sql/net_serv.cc
index 49454c9df2c..19f68e0b631 100644
--- a/sql/net_serv.cc
+++ b/sql/net_serv.cc
@@ -73,9 +73,9 @@ extern pthread_mutex_t LOCK_bytes_sent , LOCK_bytes_received;
 #include "thr_alarm.h"
 
 #define TEST_BLOCKING		8
-#define MAX_THREE_BYTES (256L*256L*256L-1)
+#define MAX_PACKET_LENGTH (256L*256L*256L-1)
 
-static int net_write_buff(NET *net,const char *packet,ulong len);
+static my_bool net_write_buff(NET *net,const char *packet,ulong len);
 
 
 	/* Init with packet info */
@@ -131,12 +131,16 @@ static my_bool net_realloc(NET *net, ulong length)
 {
   uchar *buff;
   ulong pkt_length;
+  DBUG_ENTER("net_realloc");
+  DBUG_PRINT("enter",("length: %lu", length));
+
   if (length >= net->max_packet_size)
   {
-    DBUG_PRINT("error",("Packet too large (%lu)", length));
+    DBUG_PRINT("error",("Packet too large. Max sixe: %lu",
+			net->max_packet_size));
     net->error=1;
     net->last_errno=ER_NET_PACKET_TOO_LARGE;
-    return 1;
+    DBUG_RETURN(1);
   }
   pkt_length = (length+IO_SIZE-1) & ~(IO_SIZE-1); 
   /*
@@ -151,11 +155,11 @@ static my_bool net_realloc(NET *net, ulong length)
 #ifdef MYSQL_SERVER
     net->last_errno=ER_OUT_OF_RESOURCES;
 #endif
-    return 1;
+    DBUG_RETURN(1);
   }
   net->buff=net->write_pos=buff;
   net->buff_end=buff+(net->max_packet=pkt_length);
-  return 0;
+  DBUG_RETURN(0);
 }
 
 	/* Remove unwanted characters from connection */
@@ -217,13 +221,13 @@ my_net_write(NET *net,const char *packet,ulong len)
 {
   uchar buff[NET_HEADER_SIZE];
   /*
-    Big packets are handled by splitting them in packets of MAX_THREE_BYTES
-    length. The last packet is always a packet that is < MAX_THREE_BYTES.
-    (The last packet may even have a lengt of 0)
+    Big packets are handled by splitting them in packets of MAX_PACKET_LENGTH
+    length. The last packet is always a packet that is < MAX_PACKET_LENGTH.
+    (The last packet may even have a length of 0)
   */
-  while (len >= MAX_THREE_BYTES)
+  while (len >= MAX_PACKET_LENGTH)
   {
-    const ulong z_size = MAX_THREE_BYTES;
+    const ulong z_size = MAX_PACKET_LENGTH;
     int3store(buff, z_size);
     buff[3]= (uchar) net->pkt_nr++;
     if (net_write_buff(net, (char*) buff, NET_HEADER_SIZE) ||
@@ -238,7 +242,7 @@ my_net_write(NET *net,const char *packet,ulong len)
   if (net_write_buff(net,(char*) buff,NET_HEADER_SIZE))
     return 1;
   DBUG_DUMP("packet_header",(char*) buff,NET_HEADER_SIZE);
-  return net_write_buff(net,packet,len);
+  return test(net_write_buff(net,packet,len));
 }
 
 /*
@@ -256,64 +260,107 @@ net_write_command(NET *net,uchar command,const char *packet,ulong len)
   ulong length=len+1;				/* 1 extra byte for command */
   uchar buff[NET_HEADER_SIZE+1];
   uint header_size=NET_HEADER_SIZE+1;
+  DBUG_ENTER("net_write_command");
+  DBUG_PRINT("enter",("length: %lu", len));
+
   buff[4]=command;				/* For first packet */
 
-  if (length >= MAX_THREE_BYTES)
+  if (length >= MAX_PACKET_LENGTH)
   {
     /* Take into account that we have the command in the first header */
-    len= MAX_THREE_BYTES -1;
+    len= MAX_PACKET_LENGTH -1;
     do
     {
-      int3store(buff, MAX_THREE_BYTES);
+      int3store(buff, MAX_PACKET_LENGTH);
       buff[3]= (uchar) net->pkt_nr++;
       if (net_write_buff(net,(char*) buff, header_size) ||
 	  net_write_buff(net,packet,len))
-	return 1;
+	DBUG_RETURN(1);
       packet+= len;
-      length-= MAX_THREE_BYTES;
-      len=MAX_THREE_BYTES;
-      header_size=NET_HEADER_SIZE;
-    } while (length >= MAX_THREE_BYTES);
+      length-= MAX_PACKET_LENGTH;
+      len= MAX_PACKET_LENGTH;
+      header_size= NET_HEADER_SIZE;
+    } while (length >= MAX_PACKET_LENGTH);
     len=length;					/* Data left to be written */
   }
   int3store(buff,length);
   buff[3]= (uchar) net->pkt_nr++;
-  return test(net_write_buff(net,(char*) buff,header_size) ||
-	      net_write_buff(net,packet,len) || net_flush(net));
+  DBUG_RETURN(test(net_write_buff(net,(char*) buff,header_size) ||
+		   net_write_buff(net,packet,len) || net_flush(net)));
 }
 
 /*
   Caching the data in a local buffer before sending it.
-  One can force the buffer to be flushed with 'net_flush'.
 
+  SYNOPSIS
+    net_write_buff()
+    net		Network handler
+    packet	Packet to send
+    len		Length of packet
+
+  DESCRIPTION
+    Fill up net->buffer and send it to the client when full.
+
+    If the rest of the to-be-sent-packet is bigger than buffer,
+    send it in one big block (to avoid copying to internal buffer).
+    If not, copy the rest of the data to the buffer and return without
+    sending data.
+
+  NOTES
+    The cached buffer can be sent as it is with 'net_flush()'.
+
+    In this code we have to be careful to not send a packet longer than
+    MAX_PACKET_LENGTH to net_real_write() if we are using the compressed protocol
+    as we store the length of the compressed packet in 3 bytes.
+
+  RETURN
+  0	ok
+  1
 */
 
-static int
+static my_bool
 net_write_buff(NET *net,const char *packet,ulong len)
 {
-  ulong left_length=(ulong) (net->buff_end - net->write_pos);
+  ulong left_length;
+  if (net->compress && net->max_packet > MAX_PACKET_LENGTH)
+    left_length= MAX_PACKET_LENGTH - (net->write_pos - net->buff);
+  else
+    left_length= (ulong) (net->buff_end - net->write_pos);
 
   if (len > left_length)
   {
-    memcpy((char*) net->write_pos,packet,left_length);
-    if (net_real_write(net,(char*) net->buff,net->max_packet))
-      return 1;
-    net->write_pos=net->buff;
-    packet+=left_length;
-    len-= left_length;
-    left_length= net->max_packet;
-
-    /* Send out rest of the blocks as full sized blocks */
-    while (len > left_length)
+    if (net->write_pos != net->buff)
     {
-      if (net_real_write(net, packet, left_length))
+      /* Fill up already used packet and write it */
+      memcpy((char*) net->write_pos,packet,left_length);
+      if (net_real_write(net,(char*) net->buff, 
+			 (ulong) (net->write_pos - net->buff) + left_length))
 	return 1;
+      net->write_pos= net->buff;
       packet+= left_length;
       len-= left_length;
     }
+    if (net->compress)
+    {
+      /*
+	We can't have bigger packets than 16M with compression
+	Because the uncompressed length is stored in 3 bytes
+      */
+      left_length= MAX_PACKET_LENGTH;
+      while (len > left_length)
+      {
+	if (net_real_write(net, packet, left_length))
+	  return 1;
+	packet+= left_length;
+	len-= left_length;
+      }
+    }
+    if (len > net->max_packet)
+      return net_real_write(net, packet, len) ? 1 : 0;
+    /* Send out rest of the blocks as full sized blocks */
   }
   memcpy((char*) net->write_pos,packet,len);
-  net->write_pos+=len;
+  net->write_pos+= len;
   return 0;
 }
 
@@ -364,11 +411,7 @@ net_real_write(NET *net,const char *packet,ulong len)
     memcpy(b+header_length,packet,len);
 
     if (my_compress((byte*) b+header_length,&len,&complen))
-    {
-      DBUG_PRINT("warning",
-		 ("Compression error; Continuing without compression"));
       complen=0;
-    }
     int3store(&b[NET_HEADER_SIZE],complen);
     int3store(b,len);
     b[3]=(uchar) (net->compress_pkt_nr++);
@@ -469,28 +512,15 @@ net_real_write(NET *net,const char *packet,ulong len)
 *****************************************************************************/
 
 #ifndef NO_ALARM
-/*
-  Help function to clear the commuication buffer when we get a too
-  big packet
-*/
 
-static void my_net_skip_rest(NET *net, uint32 remain, thr_alarm_t *alarmed)
+static my_bool net_safe_read(NET *net, char *buff, uint32 length,
+			     thr_alarm_t *alarmed)
 {
-  ALARM alarm_buff;
   uint retry_count=0;
-  my_bool old_mode;
-  uint32 old=remain;
-
-  if (!thr_alarm_in_use(&alarmed))
-  {
-    if (!thr_alarm(alarmed,net->read_timeout,&alarm_buff) ||
-	vio_blocking(net->vio, TRUE, &old_mode) < 0)
-      return;					/* Can't setup, abort */
-  }
-  while (remain > 0)
+  while (length > 0)
   {
-    ulong length;
-    if ((int) (length=vio_read(net->vio,(char*) net->buff,remain)) <= 0L)
+    int tmp;
+    if ((tmp=vio_read(net->vio,(char*) net->buff, length)) <= 0)
     {
       my_bool interrupted = vio_should_retry(net->vio);
       if (!thr_got_alarm(&alarmed) && interrupted)
@@ -498,17 +528,60 @@ static void my_net_skip_rest(NET *net, uint32 remain, thr_alarm_t *alarmed)
 	if (retry_count++ < net->retry_count)
 	  continue;
       }
-      return;
+      return 1;
     }
-    remain -= (uint32) length;
-    if (!remain && old==MAX_THREE_BYTES && 
-	(length=vio_read(net->vio,(char*) net->buff,NET_HEADER_SIZE)))
+    length-= tmp;
+  }
+  return 0;
+}
+
+/*
+  Help function to clear the commuication buffer when we get a too big packet.
+
+  SYNOPSIS
+    my_net_skip_rest()
+    net		Communication handle
+    remain	Bytes to read
+    alarmed	Parameter for thr_alarm()
+    alarm_buff	Parameter for thr_alarm()
+
+  RETURN VALUES
+   0	Was able to read the whole packet
+   1	Got mailformed packet from client
+*/
+
+static my_bool my_net_skip_rest(NET *net, uint32 remain, thr_alarm_t *alarmed,
+				ALARM *alarm_buff)
+{
+  uint32 old=remain;
+  DBUG_ENTER("my_net_skip_rest");
+  DBUG_PRINT("enter",("bytes_to_skip: %u", (uint) remain));
+
+  if (!thr_alarm_in_use(&alarmed))
+  {
+    my_bool old_mode;
+    if (!thr_alarm(alarmed,net->read_timeout, alarm_buff) ||
+	vio_blocking(net->vio, TRUE, &old_mode) < 0)
+      DBUG_RETURN(1);				/* Can't setup, abort */
+  }
+  for (;;)
+  {
+    while (remain > 0)
     {
-      old=remain= uint3korr(net->buff);
-      net->pkt_nr++;
+      uint length= min(remain, net->max_packet);
+      if (net_safe_read(net, (char*) net->buff, length, alarmed))
+	DBUG_RETURN(1);
+      statistic_add(bytes_received, length, &LOCK_bytes_received);
+      remain -= (uint32) length;
     }
-    statistic_add(bytes_received,length,&LOCK_bytes_received);
+    if (old != MAX_PACKET_LENGTH)
+      break;
+    if (net_safe_read(net, (char*) net->buff, NET_HEADER_SIZE, alarmed))
+      DBUG_RETURN(1);
+    old=remain= uint3korr(net->buff);
+    net->pkt_nr++;
   }
+  DBUG_RETURN(0);
 }
 #endif /* NO_ALARM */
 
@@ -607,9 +680,8 @@ my_real_read(NET *net, ulong *complen)
 	    continue;
 	  }
 #endif
-	  DBUG_PRINT("error",("Couldn't read packet: remain: %lu  errno: %d  length: %ld  alarmed: %d",
-			      remain,vio_errno(net->vio), length,
-			      thr_got_alarm(&alarmed)));
+	  DBUG_PRINT("error",("Couldn't read packet: remain: %u  errno: %d  length: %ld",
+			      remain, vio_errno(net->vio), length));
 	  len= packet_error;
 	  net->error=2;				/* Close socket */
 #ifdef MYSQL_SERVER
@@ -667,19 +739,12 @@ my_real_read(NET *net, ulong *complen)
 	{
 	  if (net_realloc(net,helping))
 	  {
-#ifdef MYSQL_SERVER
-#ifndef NO_ALARM
-	    if (net->compress)
-	    {
-	      len= packet_error;
-	      goto end;
-	    }
-	    my_net_skip_rest(net, (uint32) len, &alarmed);
-	    len=0;
-#endif
-#else
-	    len= packet_error;          /* Return error */
+#if defined(MYSQL_SERVER) && !defined(NO_ALARM)
+	    if (!net->compress &&
+		!my_net_skip_rest(net, (uint32) len, &alarmed, &alarm_buff))
+	      net->error= 3;		/* Successfully skiped packet */
 #endif
+	    len= packet_error;          /* Return error and close connection */
 	    goto end;
 	  }
 	}
@@ -723,7 +788,7 @@ my_net_read(NET *net)
   {
 #endif
     len = my_real_read(net,&complen);
-    if (len == MAX_THREE_BYTES)
+    if (len == MAX_PACKET_LENGTH)
     {
       /* First packet of a multi-packet.  Concatenate the packets */
       ulong save_pos = net->where_b;
@@ -733,7 +798,7 @@ my_net_read(NET *net)
 	net->where_b += len;
 	total_length += len;
 	len = my_real_read(net,&complen);
-      } while (len == MAX_THREE_BYTES);
+      } while (len == MAX_PACKET_LENGTH);
       if (len != packet_error)
 	len+= total_length;
       net->where_b = save_pos;
@@ -791,7 +856,7 @@ my_net_read(NET *net)
 	  else
 	    start_of_packet+= read_length + NET_HEADER_SIZE;
 
-	  if (read_length != MAX_THREE_BYTES)	    /* last package */
+	  if (read_length != MAX_PACKET_LENGTH)	/* last package */
 	  {
 	    multi_byte_packet= 0;		/* No last zero len packet */
 	    break;