Bug#11766191:INVALID MEMORY READ IN DO_DIV_MOD WITH DOUBLY ASSIGNED VARIABLES

Bug#12608543: CRASHES WITH DECIMALS AND STATEMENT NEEDS TO BE REPREPARED ERRORS

Backporting these two fixes to 5.1 
Added unittest to test my_decimal construtor and assignment operators

sql/my_decimal.h:
  Added constructor and assignment operators for my_decimal
unittest/my_decimal/my_decimal-t.cc:
  Added test to check constructor and assignment operators for my_decimal

configure.in

@@ -2877,7 +2877,7 @@ fi
 AC_CONFIG_FILES(Makefile extra/Makefile mysys/Makefile dnl
  unittest/Makefile unittest/mytap/Makefile unittest/mytap/t/Makefile dnl
  unittest/mysys/Makefile unittest/strings/Makefile dnl
- unittest/examples/Makefile dnl
+ unittest/examples/Makefile unittest/my_decimal/Makefile dnl
  strings/Makefile regex/Makefile storage/Makefile dnl
  man/Makefile BUILD/Makefile vio/Makefile dnl
  libmysql/Makefile libmysql_r/Makefile client/Makefile dnl

sql/item_cmpfunc.cc

@@ -2077,7 +2077,6 @@ void Item_func_interval::fix_length_and_dec()
             if (dec != &range->dec)
             {
               range->dec= *dec;
-              range->dec.fix_buffer_pointer();
             }
           }
           else

sql/my_decimal.h

 /*
-   Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -111,6 +111,31 @@ class my_decimal :public decimal_t
 #endif
 
 public:
+  my_decimal(const my_decimal &rhs) : decimal_t(rhs)
+  {
+#if !defined(DBUG_OFF)
+    foo1= test_value;
+    foo2= test_value;
+#endif
+    for (uint i= 0; i < DECIMAL_BUFF_LENGTH; i++)
+      buffer[i]= rhs.buffer[i];
+    fix_buffer_pointer();
+  }
+
+  my_decimal& operator=(const my_decimal &rhs)
+  {
+#if !defined(DBUG_OFF)
+    foo1= test_value;
+    foo2= test_value;
+#endif
+    if (this == &rhs)
+      return *this;
+    decimal_t::operator=(rhs);
+    for (uint i= 0; i < DECIMAL_BUFF_LENGTH; i++)
+      buffer[i]= rhs.buffer[i];
+    fix_buffer_pointer();
+    return *this;
+  }
 
   void init()
   {
@@ -147,8 +172,6 @@ class my_decimal :public decimal_t
   void swap(my_decimal &rhs)
   {
     swap_variables(my_decimal, *this, rhs);
-    /* Swap the buffer pointers back */
-    swap_variables(decimal_digit_t *, buf, rhs.buf);
   }
 };
 

sql/sql_analyse.cc

 /*
-   Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -523,9 +523,6 @@ void field_decimal::add()
   {
     found = 1;
     min_arg = max_arg = sum[0] = *dec;
-    min_arg.fix_buffer_pointer();
-    max_arg.fix_buffer_pointer();
-    sum[0].fix_buffer_pointer();
     my_decimal_mul(E_DEC_FATAL_ERROR, sum_sqr, dec, dec);
     cur_sum= 0;
     min_length = max_length = length;
@@ -547,12 +544,10 @@ void field_decimal::add()
     if (my_decimal_cmp(dec, &min_arg) < 0)
     {
       min_arg= *dec;
-      min_arg.fix_buffer_pointer();
     }
     if (my_decimal_cmp(dec, &max_arg) > 0)
     {
       max_arg= *dec;
-      max_arg.fix_buffer_pointer();
     }
   }
 }

strings/decimal.c

-/* Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights
+ * reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -14,8 +15,6 @@
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */
 
-#line 18 "decimal.c"
-
 /*
 =======================================================================
   NOTE: this library implements SQL standard "exact numeric" type

unittest/Makefile.am

-# Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2006, 2013, Oracle and/or its affiliates. All rights reserved.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -13,12 +13,12 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
-SUBDIRS      = mytap . mysys examples strings
+SUBDIRS      = mytap . mysys examples strings my_decimal
 
 EXTRA_DIST = unit.pl
 CLEANFILES = unit
 
-unittests = mytap mysys strings @mysql_se_unittest_dirs@  @mysql_pg_unittest_dirs@
+unittests = mytap mysys strings my_decimal @mysql_se_unittest_dirs@  @mysql_pg_unittest_dirs@
 
 test:
 	perl unit.pl run $(unittests)

unittest/my_decimal/Makefile.am

+# Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+AM_CPPFLAGS      = @ZLIB_INCLUDES@ -I$(top_builddir)/include 
+AM_CPPFLAGS     += -I$(top_srcdir)/include -I$(top_srcdir)/unittest/mytap
+AM_CPPFLAGS     += -I$(top_srcdir)/sql
+
+LDADD 		= $(top_builddir)/unittest/mytap/libmytap.a \
+		  $(top_builddir)/mysys/libmysys.a \
+		  $(top_builddir)/strings/libmystrings.a \
+		  $(top_builddir)/dbug/libdbug.a \
+		  $(top_builddir)/mysys/libmysys.a \
+		  $(top_builddir)/strings/libmystrings.a
+
+my_decimal_t_SOURCES = my_decimal-t.cc
+
+noinst_PROGRAMS  = my_decimal-t
+
+# Don't update the files from bitkeeper
+%::SCCS/s.%

unittest/my_decimal/my_decimal-t.cc

+/* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */
+
+#include "my_config.h"
+#include "config.h"
+#include <tap.h>
+#include <my_global.h>
+#include <my_sys.h>
+#include <m_string.h>
+#include <sql_string.h>
+#include <my_decimal.h>
+
+
+
+/*
+  Test my_decimal constuctor and assignement operators
+*/
+static int
+test_copy_and_compare()
+{
+  my_decimal d1,d2;
+
+  ulonglong val= 42;
+
+  ok(ulonglong2decimal(val,&d1) == 0, "Pass");
+  d2= d1;
+  my_decimal d3(d1);
+
+  ok(my_decimal_cmp(&d1, &d2) == 0, "Pass");
+  ok(my_decimal_cmp(&d2, &d3) == 0, "Pass");
+  ok(my_decimal_cmp(&d3, &d1) == 0,"Pass");
+
+  ulonglong val1, val2, val3;
+  ok(decimal2ulonglong(&d1, &val1) == 0, "Pass");
+  ok(decimal2ulonglong(&d2, &val2) == 0,"Pass");
+  ok(decimal2ulonglong(&d3, &val3) == 0,"Pass");
+
+  ok(val == val1,"Pass");
+  ok(val == val2,"Pass");
+  ok(val == val3,"Pass");
+
+  // The CTOR/operator=() generated by the compiler would fail here:
+  val= 45;
+  ok(ulonglong2decimal(val, &d1) == 0,"Pass");
+  ok(my_decimal_cmp(&d1, &d2) == 1,"Pass");
+  ok(my_decimal_cmp(&d1, &d3) == 1,"Pass");
+
+  return 0;
+
+}
+
+int main()
+{
+  plan(13);
+  diag("Testing my_decimal constructor and assignment operators");
+
+  test_copy_and_compare();
+  
+  return exit_status();
+}