Add support for signed sysvars.

Make max_user_connections signed, with min allowed value being -1.

include/mysql/plugin.h

@@ -159,12 +159,18 @@ MARIA_DECLARE_PLUGIN__(NAME, \
 */
 enum enum_mysql_show_type
 {
-  SHOW_UNDEF, SHOW_BOOL, SHOW_INT, SHOW_LONG,
-  SHOW_LONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
+  SHOW_UNDEF, SHOW_BOOL, SHOW_UINT, SHOW_ULONG,
+  SHOW_ULONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
   SHOW_ARRAY, SHOW_FUNC, SHOW_DOUBLE,
+  SHOW_SINT, SHOW_SLONG, SHOW_SLONGLONG,
   SHOW_always_last
 };
 
+/* backward compatibility mapping. */
+#define SHOW_INT      SHOW_UINT
+#define SHOW_LONG     SHOW_ULONG
+#define SHOW_LONGLONG SHOW_ULONGLONG
+
 struct st_mysql_show_var {
   const char *name;
   char *value;

include/mysql/plugin_audit.h.pp

@@ -89,9 +89,10 @@ struct st_mysql_xid {
 typedef struct st_mysql_xid MYSQL_XID;
 enum enum_mysql_show_type
 {
-  SHOW_UNDEF, SHOW_BOOL, SHOW_INT, SHOW_LONG,
-  SHOW_LONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
+  SHOW_UNDEF, SHOW_BOOL, SHOW_UINT, SHOW_ULONG,
+  SHOW_ULONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
   SHOW_ARRAY, SHOW_FUNC, SHOW_DOUBLE,
+  SHOW_SINT, SHOW_SLONG, SHOW_SLONGLONG,
   SHOW_always_last
 };
 struct st_mysql_show_var {

include/mysql/plugin_auth.h.pp

@@ -89,9 +89,10 @@ struct st_mysql_xid {
 typedef struct st_mysql_xid MYSQL_XID;
 enum enum_mysql_show_type
 {
-  SHOW_UNDEF, SHOW_BOOL, SHOW_INT, SHOW_LONG,
-  SHOW_LONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
+  SHOW_UNDEF, SHOW_BOOL, SHOW_UINT, SHOW_ULONG,
+  SHOW_ULONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
   SHOW_ARRAY, SHOW_FUNC, SHOW_DOUBLE,
+  SHOW_SINT, SHOW_SLONG, SHOW_SLONGLONG,
   SHOW_always_last
 };
 struct st_mysql_show_var {

include/mysql/plugin_ftparser.h.pp

@@ -89,9 +89,10 @@ struct st_mysql_xid {
 typedef struct st_mysql_xid MYSQL_XID;
 enum enum_mysql_show_type
 {
-  SHOW_UNDEF, SHOW_BOOL, SHOW_INT, SHOW_LONG,
-  SHOW_LONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
+  SHOW_UNDEF, SHOW_BOOL, SHOW_UINT, SHOW_ULONG,
+  SHOW_ULONGLONG, SHOW_CHAR, SHOW_CHAR_PTR,
   SHOW_ARRAY, SHOW_FUNC, SHOW_DOUBLE,
+  SHOW_SINT, SHOW_SLONG, SHOW_SLONGLONG,
   SHOW_always_last
 };
 struct st_mysql_show_var {

mysql-test/suite/sys_vars/r/max_user_connections_basic.result

@@ -51,7 +51,7 @@ Warnings:
 Warning	1292	Truncated incorrect max_user_connections value: '-1024'
 SELECT @@global.max_user_connections;
 @@global.max_user_connections
-0
+-1
 SET @@global.max_user_connections = 4294967296;
 Warnings:
 Warning	1292	Truncated incorrect max_user_connections value: '4294967296'
@@ -59,11 +59,9 @@ SELECT @@global.max_user_connections;
 @@global.max_user_connections
 2147483647
 SET @@global.max_user_connections = -1;
-Warnings:
-Warning	1292	Truncated incorrect max_user_connections value: '-1'
 SELECT @@global.max_user_connections;
 @@global.max_user_connections
-0
+-1
 SET @@global.max_user_connections = 429496729500;
 Warnings:
 Warning	1292	Truncated incorrect max_user_connections value: '429496729500'

mysql-test/t/user_limits.test

-skip enable when max_user_connections can be negative
 #
 # Test behavior of various per-account limits (aka quotas)
 #

sql/item_func.cc

@@ -5491,16 +5491,15 @@ void Item_func_get_system_var::fix_length_and_dec()
 
   switch (var->show_type())
   {
-    case SHOW_LONG:
-    case SHOW_INT:
     case SHOW_HA_ROWS:
-      unsigned_flag= TRUE; //var->show_type() != SHOW_INT;
-      collation.set_numeric();
-      fix_char_length(MY_INT64_NUM_DECIMAL_DIGITS);
-      decimals=0;
-      break;
-    case SHOW_LONGLONG:
+    case SHOW_UINT:
+    case SHOW_ULONG:
+    case SHOW_ULONGLONG:
       unsigned_flag= TRUE;
+      /* fall through */
+    case SHOW_SINT:
+    case SHOW_SLONG:
+    case SHOW_SLONGLONG:
       collation.set_numeric();
       fix_char_length(MY_INT64_NUM_DECIMAL_DIGITS);
       decimals=0;
@@ -5535,13 +5534,11 @@ void Item_func_get_system_var::fix_length_and_dec()
       break;
     case SHOW_BOOL:
     case SHOW_MY_BOOL:
-      unsigned_flag= FALSE;
       collation.set_numeric();
       fix_char_length(1);
       decimals=0;
       break;
     case SHOW_DOUBLE:
-      unsigned_flag= FALSE;
       decimals= 6;
       collation.set_numeric();
       fix_char_length(DBL_DIG + 6);
@@ -5565,9 +5562,12 @@ enum Item_result Item_func_get_system_var::result_type() const
   {
     case SHOW_BOOL:
     case SHOW_MY_BOOL:
-    case SHOW_INT:
-    case SHOW_LONG:
-    case SHOW_LONGLONG:
+    case SHOW_SINT:
+    case SHOW_SLONG:
+    case SHOW_SLONGLONG:
+    case SHOW_UINT:
+    case SHOW_ULONG:
+    case SHOW_ULONGLONG:
     case SHOW_HA_ROWS:
       return INT_RESULT;
     case SHOW_CHAR: 
@@ -5589,9 +5589,12 @@ enum_field_types Item_func_get_system_var::field_type() const
   {
     case SHOW_BOOL:
     case SHOW_MY_BOOL:
-    case SHOW_INT:
-    case SHOW_LONG:
-    case SHOW_LONGLONG:
+    case SHOW_SINT:
+    case SHOW_SLONG:
+    case SHOW_SLONGLONG:
+    case SHOW_UINT:
+    case SHOW_ULONG:
+    case SHOW_ULONGLONG:
     case SHOW_HA_ROWS:
       return MYSQL_TYPE_LONGLONG;
     case SHOW_CHAR: 
@@ -5660,9 +5663,12 @@ longlong Item_func_get_system_var::val_int()
 
   switch (var->show_type())
   {
-    case SHOW_INT:      get_sys_var_safe (uint);
-    case SHOW_LONG:     get_sys_var_safe (ulong);
-    case SHOW_LONGLONG: get_sys_var_safe (ulonglong);
+    case SHOW_SINT:     get_sys_var_safe (int);
+    case SHOW_SLONG:    get_sys_var_safe (long);
+    case SHOW_SLONGLONG:get_sys_var_safe (longlong);
+    case SHOW_UINT:     get_sys_var_safe (uint);
+    case SHOW_ULONG:    get_sys_var_safe (ulong);
+    case SHOW_ULONGLONG:get_sys_var_safe (ulonglong);
     case SHOW_HA_ROWS:  get_sys_var_safe (ha_rows);
     case SHOW_BOOL:     get_sys_var_safe (bool);
     case SHOW_MY_BOOL:  get_sys_var_safe (my_bool);
@@ -5763,9 +5769,12 @@ String* Item_func_get_system_var::val_str(String* str)
       break;
     }
 
-    case SHOW_INT:
-    case SHOW_LONG:
-    case SHOW_LONGLONG:
+    case SHOW_SINT:
+    case SHOW_SLONG:
+    case SHOW_SLONGLONG:
+    case SHOW_UINT:
+    case SHOW_ULONG:
+    case SHOW_ULONGLONG:
     case SHOW_HA_ROWS:
     case SHOW_BOOL:
     case SHOW_MY_BOOL:
@@ -5855,9 +5864,12 @@ double Item_func_get_system_var::val_real()
         cache_present|= GET_SYS_VAR_CACHE_DOUBLE;
         return cached_dval;
       }
-    case SHOW_INT:
-    case SHOW_LONG:
-    case SHOW_LONGLONG:
+    case SHOW_SINT:
+    case SHOW_SLONG:
+    case SHOW_SLONGLONG:
+    case SHOW_UINT:
+    case SHOW_ULONG:
+    case SHOW_ULONGLONG:
     case SHOW_HA_ROWS:
     case SHOW_BOOL:
     case SHOW_MY_BOOL:

sql/set_var.cc

@@ -308,7 +308,7 @@ void sys_var::do_deprecated_warning(THD *thd)
 bool throw_bounds_warning(THD *thd, const char *name,
                           bool fixed, bool is_unsigned, longlong v)
 {
-  if (fixed || (!is_unsigned && v < 0))
+  if (fixed)
   {
     char buf[22];
 

sql/set_var.h

@@ -201,7 +201,8 @@ public:
   enum_var_type type;
   union ///< temp storage to hold a value between sys_var::check and ::update
   {
-    ulonglong ulonglong_value;          ///< for all integer, set, enum sysvars
+    ulonglong ulonglong_value;          ///< for unsigned integer, set, enum sysvars
+    longlong longlong_value;            ///< for signed integer
     double double_value;                ///< for Sys_var_double
     plugin_ref plugin;                  ///< for Sys_var_plugin
     Time_zone *time_zone;               ///< for Sys_var_tz

sql/sql_class.h

@@ -520,7 +520,7 @@ typedef struct system_variables
   ulong query_cache_type;
   ulong tx_isolation;
   ulong updatable_views_with_limit;
-  uint max_user_connections;
+  int max_user_connections;
   /**
     In slave thread we need to know in behalf of which
     thread the query is being run to replicate temp tables properly

sql/sql_connect.cc

@@ -130,7 +130,7 @@ int check_for_max_user_connections(THD *thd, USER_CONN *uc)
   /* Root is not affected by the value of max_user_connections */
   if (global_system_variables.max_user_connections &&
       !uc->user_resources.user_conn &&
-      global_system_variables.max_user_connections < (uint) uc->connections &&
+      global_system_variables.max_user_connections < uc->connections &&
       !(thd->security_ctx->master_access & SUPER_ACL))
   {
     my_error(ER_TOO_MANY_USER_CONNECTIONS, MYF(0), uc->user);

sql/sql_show.cc

@@ -2367,14 +2367,14 @@ static bool show_status_array(THD *thd, const char *wild,
         case SHOW_LONG_STATUS:
           value= ((char *) status_var + (intptr) value);
           /* fall through */
-        case SHOW_LONG:
+        case SHOW_ULONG:
         case SHOW_LONG_NOFLUSH: // the difference lies in refresh_status()
           end= int10_to_str(*(long*) value, buff, 10);
           break;
         case SHOW_LONGLONG_STATUS:
           value= ((char *) status_var + (intptr) value);
           /* fall through */
-        case SHOW_LONGLONG:
+        case SHOW_ULONGLONG:
           end= longlong10_to_str(*(longlong*) value, buff, 10);
           break;
         case SHOW_HA_ROWS:
@@ -2386,9 +2386,18 @@ static bool show_status_array(THD *thd, const char *wild,
         case SHOW_MY_BOOL:
           end= strmov(buff, *(my_bool*) value ? "ON" : "OFF");
           break;
-        case SHOW_INT:
+        case SHOW_UINT:
           end= int10_to_str((long) *(uint*) value, buff, 10);
           break;
+        case SHOW_SINT:
+          end= int10_to_str((long) *(uint*) value, buff, -10);
+          break;
+        case SHOW_SLONG:
+          end= int10_to_str(*(long*) value, buff, -10);
+          break;
+        case SHOW_SLONGLONG:
+          end= longlong10_to_str(*(longlong*) value, buff, -10);
+          break;
         case SHOW_HAVE:
         {
           SHOW_COMP_OPTION tmp= *(SHOW_COMP_OPTION*) value;

sql/sys_vars.cc

@@ -1255,7 +1255,7 @@ static Sys_var_max_user_conn Sys_max_user_connections(
        "The maximum number of active connections for a single user "
        "(0 = no limit)",
        SESSION_VAR(max_user_connections), CMD_LINE(REQUIRED_ARG),
-       VALID_RANGE(0, INT_MAX), DEFAULT(0), BLOCK_SIZE(1), NO_MUTEX_GUARD,
+       VALID_RANGE(-1, INT_MAX), DEFAULT(0), BLOCK_SIZE(1), NO_MUTEX_GUARD,
        NOT_IN_BINLOG, ON_CHECK(if_checking_enabled));
 
 static Sys_var_ulong Sys_max_tmp_tables(

sql/sys_vars.h

@@ -104,21 +104,22 @@ struct CMD_LINE
 };
 
 /**
-  Sys_var_unsigned template is used to generate Sys_var_* classes
-  for variables that represent the value as an unsigned integer.
-  They are Sys_var_uint, Sys_var_ulong, Sys_var_harows, Sys_var_ulonglong.
+  Sys_var_integer template is used to generate Sys_var_* classes
+  for variables that represent the value as an integer number.
+  They are Sys_var_uint, Sys_var_ulong, Sys_var_harows, Sys_var_ulonglong,
+  Sys_var_int.
 
   An integer variable has a minimal and maximal values, and a "block_size"
   (any valid value of the variable must be divisible by the block_size).
 
   Class specific constructor arguments: min, max, block_size
-  Backing store: uint, ulong, ha_rows, ulonglong, depending on the Sys_var_*
+  Backing store: int, uint, ulong, ha_rows, ulonglong, depending on the class
 */
 template <typename T, ulong ARGT, enum enum_mysql_show_type SHOWT>
-class Sys_var_unsigned: public sys_var
+class Sys_var_integer: public sys_var
 {
 public:
-  Sys_var_unsigned(const char *name_arg,
+  Sys_var_integer(const char *name_arg,
           const char *comment, int flag_args, ptrdiff_t off, size_t size,
           CMD_LINE getopt,
           T min_val, T max_val, T def_val, uint block_size, PolyLock *lock=0,
@@ -147,24 +148,49 @@ public:
   }
   bool do_check(THD *thd, set_var *var)
   {
-    my_bool fixed= FALSE;
+    my_bool fixed= FALSE, unused;
+    longlong v= var->value->val_int();
+
+    if ((ARGT == GET_HA_ROWS) || (ARGT == GET_UINT) ||
+        (ARGT == GET_ULONG)   || (ARGT == GET_ULL))
+    {
       ulonglong uv;
-    longlong v;
 
-    v= var->value->val_int();
-    if (var->value->unsigned_flag)
-      uv= (ulonglong) v;
+      /*
+        if the value is signed and negative,
+        and a variable is unsigned, it is set to zero
+      */
+      if ((fixed= (!var->value->unsigned_flag && v < 0)))
+        uv= 0;
       else
-      uv= (ulonglong) (v < 0 ? 0 : v);
+        uv= v;
 
       var->save_result.ulonglong_value=
-      getopt_ull_limit_value(uv, &option, &fixed);
+        getopt_ull_limit_value(uv, &option, &unused);
 
-    if (max_var_ptr() && var->save_result.ulonglong_value > *max_var_ptr())
+      if (max_var_ptr() && (T)var->save_result.ulonglong_value > *max_var_ptr())
         var->save_result.ulonglong_value= *max_var_ptr();
 
-    return throw_bounds_warning(thd, name.str,
-                                var->save_result.ulonglong_value != uv,
+      fixed= fixed || var->save_result.ulonglong_value != uv;
+    }
+    else
+    {
+      /*
+        if the value is unsigned and has the highest bit set
+        and a variable is signed, it is set to max signed value
+      */
+      if ((fixed= (var->value->unsigned_flag && v < 0)))
+        v= LONGLONG_MAX;
+
+      var->save_result.longlong_value=
+        getopt_ll_limit_value(v, &option, &unused);
+
+      if (max_var_ptr() && (T)var->save_result.longlong_value > *max_var_ptr())
+        var->save_result.longlong_value= *max_var_ptr();
+
+      fixed= fixed || var->save_result.longlong_value != v;
+    }
+    return throw_bounds_warning(thd, name.str, fixed,
                                 var->value->unsigned_flag, v);
   }
   bool session_update(THD *thd, set_var *var)
@@ -191,10 +217,11 @@ public:
   }
 };
 
-typedef Sys_var_unsigned<uint, GET_UINT, SHOW_INT> Sys_var_uint;
-typedef Sys_var_unsigned<ulong, GET_ULONG, SHOW_LONG> Sys_var_ulong;
-typedef Sys_var_unsigned<ha_rows, GET_HA_ROWS, SHOW_HA_ROWS> Sys_var_harows;
-typedef Sys_var_unsigned<ulonglong, GET_ULL, SHOW_LONGLONG> Sys_var_ulonglong;
+typedef Sys_var_integer<int, GET_INT, SHOW_SINT> Sys_var_int;
+typedef Sys_var_integer<uint, GET_UINT, SHOW_UINT> Sys_var_uint;
+typedef Sys_var_integer<ulong, GET_ULONG, SHOW_ULONG> Sys_var_ulong;
+typedef Sys_var_integer<ha_rows, GET_HA_ROWS, SHOW_HA_ROWS> Sys_var_harows;
+typedef Sys_var_integer<ulonglong, GET_ULL, SHOW_ULONGLONG> Sys_var_ulonglong;
 
 /**
   Helper class for variables that take values from a TYPELIB
@@ -883,7 +910,7 @@ public:
 
   Backing store: uint
 */
-class Sys_var_max_user_conn: public Sys_var_uint
+class Sys_var_max_user_conn: public Sys_var_int
 {
 public:
   Sys_var_max_user_conn(const char *name_arg,
@@ -895,7 +922,7 @@ public:
           on_check_function on_check_func=0,
           on_update_function on_update_func=0,
           uint deprecated_version=0, const char *substitute=0)
-    : Sys_var_uint(name_arg, comment, SESSION, off, size, getopt,
+    : Sys_var_int(name_arg, comment, SESSION, off, size, getopt,
               min_val, max_val, def_val, block_size,
               lock, binlog_status_arg, on_check_func, on_update_func,
               deprecated_version, substitute)
@@ -1779,9 +1806,10 @@ public:
 #ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
 template class List<set_var_base>;
 template class List_iterator_fast<set_var_base>;
-template class Sys_var_unsigned<uint, GET_UINT, SHOW_INT>;
-template class Sys_var_unsigned<ulong, GET_ULONG, SHOW_LONG>;
-template class Sys_var_unsigned<ha_rows, GET_HA_ROWS, SHOW_HA_ROWS>;
-template class Sys_var_unsigned<ulonglong, GET_ULL, SHOW_LONGLONG>;
+template class Sys_var_integer<int, GET_INT, SHOW_SINT>;
+template class Sys_var_integer<uint, GET_UINT, SHOW_INT>;
+template class Sys_var_integer<ulong, GET_ULONG, SHOW_LONG>;
+template class Sys_var_integer<ha_rows, GET_HA_ROWS, SHOW_HA_ROWS>;
+template class Sys_var_integer<ulonglong, GET_ULL, SHOW_LONGLONG>;
 #endif