Bug#31177: Server variables can't be set to their current values

additional fixes for BDB and correct assignment of both signed
and unsigned 64-bit data to unsigned system variables


mysql-test/r/ps_2myisam.result:
  account for UNSIGNED_FLAG
mysql-test/r/ps_3innodb.result:
  account for UNSIGNED_FLAG
mysql-test/r/ps_4heap.result:
  account for UNSIGNED_FLAG
mysql-test/r/ps_5merge.result:
  account for UNSIGNED_FLAG
mysql-test/r/ps_6bdb.result:
  account for UNSIGNED_FLAG
mysql-test/r/ps_7ndb.result:
  account for UNSIGNED_FLAG
mysys/my_getopt.c:
  We have correct signed/unsigned information now, so we no longer
  need to err on the side of caution.
sql/item_func.cc:
  Copy unsigned info over from entry so the item's data
  correctly describe it.
sql/mysqld.cc:
  BDB log buffer size: default can't be less than minimum
sql/set_var.cc:
  Handle signedness of in-values correctly when assigning to
  unsigned types, all the way up to 64-bit. Use handler from
  all three unsigned sysvar types.
sql/set_var.h:
  thd_ulonglong: Override default check with one for unsigned types

4 files changed, 28 insertions, 9 deletions

diff --git a/sql/item_func.cc b/sql/item_func.cc
index 2ee9973c785..019df9176c9 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4597,6 +4597,8 @@ void Item_func_get_user_var::fix_length_and_dec()
 
   if (var_entry)
   {
+    unsigned_flag= var_entry->unsigned_flag;
+
     collation.set(var_entry->collation);
     switch (var_entry->type) {
     case REAL_RESULT:
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 3900f74da7e..23a05485796 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -5679,7 +5679,7 @@ log and this option does nothing anymore.",
   {"bdb_log_buffer_size", OPT_BDB_LOG_BUFFER_SIZE,
    "The buffer that is allocated to cache index and rows for BDB tables.",
    (gptr*) &berkeley_log_buffer_size, (gptr*) &berkeley_log_buffer_size, 0,
-   GET_ULONG, REQUIRED_ARG, 0, 256*1024L, ULONG_MAX, 0, 1024, 0},
+   GET_ULONG, REQUIRED_ARG, 256*1024L, 256*1024L, ULONG_MAX, 0, 1024, 0},
   {"bdb_max_lock", OPT_BDB_MAX_LOCK,
    "The maximum number of locks you can have active on a BDB table.",
    (gptr*) &berkeley_max_lock, (gptr*) &berkeley_max_lock, 0, GET_ULONG,
diff --git a/sql/set_var.cc b/sql/set_var.cc
index 84b3f92c1ca..58b9b93b17f 100644
--- a/sql/set_var.cc
+++ b/sql/set_var.cc
@@ -115,6 +115,7 @@ static void fix_trans_mem_root(THD *thd, enum_var_type type);
 static void fix_server_id(THD *thd, enum_var_type type);
 static ulonglong fix_unsigned(THD *thd, ulonglong num,
                               const struct my_option *option_limits);
+static bool get_unsigned(THD *thd, set_var *var);
 static void throw_bounds_warning(THD *thd, const char *name, ulonglong num);
 static KEY_CACHE *create_key_cache(const char *name, uint length);
 void fix_sql_mode_var(THD *thd, enum_var_type type);
@@ -1471,6 +1472,18 @@ static ulonglong fix_unsigned(THD *thd, ulonglong num,
   return out;
 }
 
+static bool get_unsigned(THD *thd, set_var *var)
+{
+  if (var->value->unsigned_flag)
+    var->save_result.ulonglong_value= (ulonglong) var->value->val_int();
+  else
+  {
+    longlong v= var->value->val_int();
+    var->save_result.ulonglong_value= (ulonglong) ((v < 0) ? 0 : v);
+  }
+  return 0;
+}
+
 
 sys_var_long_ptr::
 sys_var_long_ptr(const char *name_arg, ulong *value_ptr_arg,
@@ -1482,9 +1495,7 @@ sys_var_long_ptr(const char *name_arg, ulong *value_ptr_arg,
 
 bool sys_var_long_ptr_global::check(THD *thd, set_var *var)
 {
-  longlong v= var->value->val_int();
-  var->save_result.ulonglong_value= v < 0 ? 0 : v;
-  return 0;
+  return get_unsigned(thd, var);
 }
 
 bool sys_var_long_ptr_global::update(THD *thd, set_var *var)
@@ -1497,9 +1508,9 @@ bool sys_var_long_ptr_global::update(THD *thd, set_var *var)
   {
 #if SIZEOF_LONG < SIZEOF_LONG_LONG
     /* Avoid overflows on 32 bit systems */
-    if (tmp > (ulonglong) ~(ulong) 0)
+    if (tmp > ULONG_MAX)
     {
-      tmp= ((ulonglong) ~(ulong) 0);
+      tmp= ULONG_MAX;
       throw_bounds_warning(thd, name, var->save_result.ulonglong_value);
     }
 #endif
@@ -1567,7 +1578,7 @@ byte *sys_var_enum::value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
 
 bool sys_var_thd_ulong::check(THD *thd, set_var *var)
 {
-  return (sys_var_thd::check(thd, var) ||
+  return (get_unsigned(thd, var) ||
           (check_func && (*check_func)(thd, var)));
 }
 
@@ -1585,9 +1596,9 @@ bool sys_var_thd_ulong::update(THD *thd, set_var *var)
   if (option_limits)
     tmp= (ulong) fix_unsigned(thd, tmp, option_limits);
 #if SIZEOF_LONG < SIZEOF_LONG_LONG
-  else if (tmp > (ulonglong) ~(ulong) 0)
+  else if (tmp > ULONG_MAX)
   {
-    tmp= ((ulonglong) ~(ulong) 0);
+    tmp= ULONG_MAX;
     throw_bounds_warning(thd, name, var->save_result.ulonglong_value);
   }
 #endif
@@ -1667,6 +1678,11 @@ byte *sys_var_thd_ha_rows::value_ptr(THD *thd, enum_var_type type,
   return (byte*) &(thd->variables.*offset);
 }
 
+bool sys_var_thd_ulonglong::check(THD *thd, set_var *var)
+{
+  return get_unsigned(thd, var);
+}
+
 bool sys_var_thd_ulonglong::update(THD *thd,  set_var *var)
 {
   ulonglong tmp= var->save_result.ulonglong_value;
diff --git a/sql/set_var.h b/sql/set_var.h
index 7b3f864f44c..93402e21258 100644
--- a/sql/set_var.h
+++ b/sql/set_var.h
@@ -365,6 +365,7 @@ public:
   void set_default(THD *thd, enum_var_type type);
   SHOW_TYPE show_type() { return SHOW_LONGLONG; }
   byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base);
+  bool check(THD *thd, set_var *var);
   bool check_default(enum_var_type type)
   {
     return type == OPT_GLOBAL && !option_limits;