Fix for conc-68: SELECT fails with "Got packet bigger than 'max_allowed_packet'" on a table with longblob column with fields greater than 15MB

libmariadb/net.c

@@ -41,6 +41,7 @@
    See bug conc-57
 */
 #undef net_buffer_length
+
 #undef max_allowed_packet
 ulong max_allowed_packet=1024L * 1024L * 1024L;
 ulong net_read_timeout=  NET_READ_TIMEOUT;
@@ -113,9 +114,9 @@ int my_net_init(NET *net, Vio* vio)
 {
   if (!(net->buff=(uchar*) my_malloc(net_buffer_length,MYF(MY_WME | MY_ZEROFILL))))
     return 1;
-  if (net_buffer_length > max_allowed_packet)
+//  if (net_buffer_length > max_allowed_packet)
-    max_allowed_packet=net_buffer_length;
+//    max_allowed_packet=net_buffer_length;
-  net->max_packet_size= 0xFFFFFF;
+  max_allowed_packet= net->max_packet_size= MAX(net_buffer_length, max_allowed_packet);
   net->buff_end=net->buff+(net->max_packet=net_buffer_length);
   net->vio = vio;
   net->error=0; net->return_status=0;
@@ -654,8 +655,7 @@ my_real_read(NET *net, size_t *complen)
 	/* The necessary size of net->buff */
 	if (helping >= net->max_packet)
 	{
-	  /* We must allocate one extra byte for the end null */
+	  if (net_realloc(net,helping))
-	  if (net_realloc(net,helping + 1))
 	  {
 #ifdef MYSQL_SERVER
 	    if (i == 1)
@@ -699,6 +699,7 @@ ulong my_net_read(NET *net)
       {
         length+= len;
         net->where_b+= (unsigned long)len;
+        len= my_real_read(net, &complen);
       } while (len == MAX_PACKET_LENGTH);
       net->where_b= last_pos;
       if (len != packet_error)

unittest/libmariadb/basic-t.c

@@ -30,6 +30,72 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "my_test.h"
 #include "ma_common.h"
 
+static int test_conc68(MYSQL *mysql)
+{
+  int rc;
+  MYSQL_RES *res;
+  MYSQL_ROW row;
+
+  rc= mysql_query(mysql, "DROP TABLE IF EXISTS t1");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_query(mysql, "CREATE TABLE t1 (a LONGBLOB)");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_query(mysql, "INSERT INTO t1 VALUES (REPEAT('A', 1024 * 1024 * 20))");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_query(mysql, "SELECT a FROM t1");
+  check_mysql_rc(rc, mysql);
+
+  if (!(res= mysql_store_result(mysql)))
+  {
+    diag("Error: %s", mysql_error(mysql));
+    return FAIL;
+  }
+
+  row= mysql_fetch_row(res);
+  FAIL_IF(strlen(row[0]) != 1024 * 1024 * 20, "Wrong length");
+  mysql_free_result(res);
+
+  return OK;
+}
+
+static int test_conc66(MYSQL *my)
+{
+  MYSQL *mysql= mysql_init(NULL);
+  int rc;
+  FILE *fp;
+
+  fp= fopen("./my.cnf", "w");
+  fprintf(fp, "[conc-66]\nuser=conc-66\npassword=\"my#pass;word\"");
+  fclose(fp);
+
+  rc= mysql_query(my, "GRANT ALL ON test.* to 'conc-66'@'%' identified by 'my#pass;word'");
+  check_mysql_rc(rc, mysql);
+  rc= mysql_query(my, "FLUSH PRIVILEGES");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_options(mysql, MYSQL_READ_DEFAULT_GROUP, "conc-66");
+  check_mysql_rc(rc, mysql);
+  rc= mysql_options(mysql, MYSQL_READ_DEFAULT_FILE, "./my.cnf");
+  check_mysql_rc(rc, mysql);
+
+  rc= mysql_real_connect(mysql, hostname, NULL, NULL, schema,
+                         port, socketname, 0);
+  if (!rc) {
+    diag("Error: %s\n", mysql_error(mysql));
+    mysql_close(mysql);
+    return FAIL;
+  }
+  mysql_close(mysql);
+
+  rc= mysql_query(my, "DROP USER 'conc-66'");
+  check_mysql_rc(rc, mysql);
+
+  return OK; 
+}
+
 static int basic_connect(MYSQL *mysql)
 {
   MYSQL_ROW row;
@@ -555,6 +621,8 @@ static int test_compressed(MYSQL *my)
 }
 
 struct my_tests_st my_tests[] = {
+  {"test_conc68", test_conc68, TEST_CONNECTION_DEFAULT, 0,  NULL,  NULL},
+  {"test_conc66", test_conc66, TEST_CONNECTION_NEW, 0,  NULL,  NULL},
   {"test_compressed", test_compressed, TEST_CONNECTION_NONE, 0,  NULL,  NULL},
   {"test_reconnect_maxpackage", test_reconnect_maxpackage, TEST_CONNECTION_NONE, 0,  NULL,  NULL},
   {"basic_connect", basic_connect, TEST_CONNECTION_NONE, 0,  NULL,  NULL},