Bug#17261 Passing a variable from a stored procedure to UDF crashes mysqld

 - Pass "buffers[i]" to val_str() in udf_handler::fix_fields insteead of NULL.
 - Add testcase for UDF that will load and run the udf_example functions 
   if available

mysql-test/include/have_udf.inc

+#
+# To check if the udf_example.so is available,
+# try to load one function from it.
+#
+#
+--require r/have_udf.require
+--disable_abort_on_error
+CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so';
+--disable_query_log
+DROP FUNCTION metaphon;
+--enable_query_log
+--enable_abort_on_error

mysql-test/r/have_udf.require

+CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so';

mysql-test/r/udf.result

+drop table if exists t1;
+CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so';
+CREATE FUNCTION myfunc_double RETURNS REAL SONAME 'udf_example.so';
+CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME 'udf_example.so';
+ERROR HY000: Can't find function 'myfunc_int_init' in library
+CREATE FUNCTION sequence RETURNS INTEGER SONAME "udf_example.so";
+CREATE FUNCTION lookup RETURNS STRING SONAME 'udf_example.so';
+CREATE FUNCTION reverse_lookup
+RETURNS STRING SONAME 'udf_example.so';
+CREATE AGGREGATE FUNCTION avgcost
+RETURNS REAL SONAME 'udf_example.so';
+select myfunc_double();
+ERROR HY000: myfunc_double must have at least on argument
+select myfunc_double(1);
+myfunc_double(1)
+49.00
+select myfunc_double(78654);
+myfunc_double(78654)
+54.00
+select myfunc_int();
+ERROR 42000: FUNCTION test.myfunc_int does not exist
+select lookup();
+ERROR HY000: Wrong arguments to lookup;  Use the source
+select lookup("127.0.0.1");
+lookup("127.0.0.1")
+127.0.0.1
+select lookup(127,0,0,1);
+ERROR HY000: Wrong arguments to lookup;  Use the source
+select lookup("localhost");
+lookup("localhost")
+127.0.0.1
+select reverse_lookup();
+ERROR HY000: Wrong number of arguments to reverse_lookup;  Use the source
+select reverse_lookup("127.0.0.1");
+reverse_lookup("127.0.0.1")
+localhost
+select reverse_lookup(127,0,0,1);
+reverse_lookup(127,0,0,1)
+localhost
+select reverse_lookup("localhost");
+reverse_lookup("localhost")
+NULL
+select avgcost();
+ERROR HY000: wrong number of arguments: AVGCOST() requires two arguments
+select avgcost(100,23.76);
+ERROR HY000: wrong argument type: AVGCOST() requires an INT and a REAL
+create table t1(sum int, price float(24));
+insert into t1 values(100, 50.00), (100, 100.00);
+select avgcost(sum, price) from t1;
+avgcost(sum, price)
+75.0000
+delete from t1;
+insert into t1 values(100, 54.33), (200, 199.99);
+select avgcost(sum, price) from t1;
+avgcost(sum, price)
+151.4367
+drop table t1;
+select metaphon('hello');
+metaphon('hello')
+HL
+CREATE PROCEDURE `XXX1`(in testval varchar(10))
+begin 
+select metaphon(testval); 
+end//
+call XXX1('hello');
+metaphon(testval)
+HL
+drop procedure xxx1;
+CREATE PROCEDURE `XXX2`()
+begin 
+declare testval varchar(10);
+set testval = 'hello';
+select metaphon(testval); 
+end//
+call XXX2();
+metaphon(testval)
+HL
+drop procedure xxx2;
+DROP FUNCTION metaphon;
+DROP FUNCTION myfunc_double;
+DROP FUNCTION myfunc_int;
+ERROR 42000: FUNCTION test.myfunc_int does not exist
+DROP FUNCTION sequence;
+DROP FUNCTION lookup;
+DROP FUNCTION reverse_lookup;
+DROP FUNCTION avgcost;

mysql-test/t/udf.test

+--source include/have_udf.inc
+#
+# To run this tests you need to compile "sql/udf_example.cc" into
+# udf_example.so and setup LD_LIBRARY_PATH to point out where 
+# the library are.
+#
+
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+# 
+# Create the example functions from udf_example
+#
+
+CREATE FUNCTION metaphon RETURNS STRING SONAME 'udf_example.so';
+CREATE FUNCTION myfunc_double RETURNS REAL SONAME 'udf_example.so';
+
+# myfunc_int does not have a myfunc_int_init function and can 
+# not be loaded unless server is started with --allow-suspicious-udfs
+--error 1127
+CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME 'udf_example.so';
+CREATE FUNCTION sequence RETURNS INTEGER SONAME "udf_example.so";
+CREATE FUNCTION lookup RETURNS STRING SONAME 'udf_example.so';
+CREATE FUNCTION reverse_lookup
+        RETURNS STRING SONAME 'udf_example.so';
+CREATE AGGREGATE FUNCTION avgcost
+        RETURNS REAL SONAME 'udf_example.so';
+
+select myfunc_double();
+select myfunc_double(1);
+select myfunc_double(78654);
+select myfunc_int();
+select lookup();
+select lookup("127.0.0.1");
+select lookup(127,0,0,1);
+select lookup("localhost");
+select reverse_lookup();
+select reverse_lookup("127.0.0.1");
+select reverse_lookup(127,0,0,1);
+select reverse_lookup("localhost");
+select avgcost();
+select avgcost(100,23.76);
+create table t1(sum int, price float(24));
+insert into t1 values(100, 50.00), (100, 100.00);
+select avgcost(sum, price) from t1;
+delete from t1;
+insert into t1 values(100, 54.33), (200, 199.99);
+select avgcost(sum, price) from t1;
+drop table t1;
+
+#------------------------------------------------------------------------
+# BUG#17261 Passing a variable from a stored procedure to UDF crashes mysqld
+#------------------------------------------------------------------------
+
+select metaphon('hello'); 
+
+delimiter //;
+CREATE PROCEDURE `XXX1`(in testval varchar(10))
+begin 
+select metaphon(testval); 
+end//
+delimiter ;//
+
+call XXX1('hello');
+drop procedure xxx1;
+
+delimiter //;
+CREATE PROCEDURE `XXX2`()
+begin 
+declare testval varchar(10);
+set testval = 'hello';
+select metaphon(testval); 
+end//
+delimiter ;//
+
+call XXX2();
+drop procedure xxx2;
+
+
+# 
+# Drop the example functions from udf_example
+#
+
+DROP FUNCTION metaphon;
+DROP FUNCTION myfunc_double;
+--error 1305
+DROP FUNCTION myfunc_int;
+DROP FUNCTION sequence;
+DROP FUNCTION lookup;
+DROP FUNCTION reverse_lookup;
+DROP FUNCTION avgcost;
+

sql/item_func.cc

@@ -2606,7 +2606,7 @@ udf_handler::fix_fields(THD *thd, Item_result_field *func,
       switch(arguments[i]->type()) {
       case Item::STRING_ITEM:			// Constant string !
       {
-	String *res=arguments[i]->val_str((String *) 0);
+	String *res=arguments[i]->val_str(&buffers[i]);
 	if (arguments[i]->null_value)
 	  continue;
 	f_args.args[i]=    (char*) res->ptr();

sql/udf_example.cc

@@ -518,7 +518,7 @@ my_bool myfunc_double_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
 {
   if (!args->arg_count)
   {
-    strcpy(message,"myfunc_double must have at least on argument");
+    strcpy(message,"myfunc_double must have at least one argument");
     return 1;
   }
   /*