Bug#32757: hang with sql_mode set when setting some global variables

If setting a system-variable provided by a plug-in failed, no OK or
error was sent in some cases, hanging the client. We now send an error
in the case from the ticket (integer-argument out of range in STRICT
mode). We also provide a semi-generic fallback message for possible
future cases like this where an error is signalled, but no message is
sent to the client. The error/warning handling is unified so it's the
same again for variables provided by plugins and those in the server
proper.


mysql-test/r/plugin.result:
  show that on out-of-range values, plugin interface throws errors
  in STRICT mode and warnings otherwise.
mysql-test/t/plugin.test:
  show that on out-of-range values, plugin interface throws errors
  in STRICT mode and warnings otherwise.
sql/set_var.cc:
  - handle signedness of values used in warnings
  - in STRICT mode, throw errors rather than warnings
sql/sql_parse.cc:
  If sql_set_variables() returns with an error but no message
  was sent to the client, send a semi-generic one so the session
  won't hang and we won't fail silently.
sql/sql_plugin.cc:
  throw a warning if more than just block-size was corrected
  (or an error in STRICT mode). use functions from set_var
  for uniform behaviour of server- and plug-in variables.
storage/example/ha_example.cc:
  Add a ULONG system variable to example plugin so
  we can test integers in the plugin-interface without
  having to depend on the presence of innobase.

mysql-test/r/plugin.result

@@ -27,3 +27,30 @@ SET GLOBAL example_enum_var= e2;
 SET GLOBAL example_enum_var= impossible;
 ERROR 42000: Variable 'enum_var' can't be set to the value of 'impossible'
 UNINSTALL PLUGIN example;
+INSTALL PLUGIN example SONAME 'ha_example.so';
+select @@session.sql_mode into @old_sql_mode;
+set session sql_mode='';
+set global example_ulong_var=500;
+select @@global.example_ulong_var;
+@@global.example_ulong_var
+500
+set global example_ulong_var=1111;
+Warnings:
+Warning	1292	Truncated incorrect ulong_var value: '1111'
+select @@global.example_ulong_var;
+@@global.example_ulong_var
+1000
+set session sql_mode='STRICT_ALL_TABLES';
+set global example_ulong_var=500;
+select @@global.example_ulong_var;
+@@global.example_ulong_var
+500
+set global example_ulong_var=1111;
+ERROR 42000: Variable 'ulong_var' can't be set to the value of '1111'
+select @@global.example_ulong_var;
+@@global.example_ulong_var
+500
+set session sql_mode=@old_sql_mode;
+set session old=bla;
+ERROR HY000: Variable 'old' is a read only variable
+UNINSTALL PLUGIN example;

mysql-test/t/plugin.test

@@ -39,3 +39,38 @@ SET GLOBAL example_enum_var= e2;
 SET GLOBAL example_enum_var= impossible;
 
 UNINSTALL PLUGIN example;
+
+
+
+#
+# Bug #32757 hang with sql_mode set when setting some global variables
+#
+INSTALL PLUGIN example SONAME 'ha_example.so';
+
+select @@session.sql_mode into @old_sql_mode;
+
+# first, try normal sql_mode (no error, send OK)
+set session sql_mode='';
+set global example_ulong_var=500;
+select @@global.example_ulong_var;
+# overflow -- correct value, but throw warning
+set global example_ulong_var=1111;
+select @@global.example_ulong_var;
+
+# now, try STRICT (error occurrs, no message is sent, so send default)
+set session sql_mode='STRICT_ALL_TABLES';
+set global example_ulong_var=500;
+select @@global.example_ulong_var;
+# overflow -- throw warning, do NOT change value
+--error ER_WRONG_VALUE_FOR_VAR
+set global example_ulong_var=1111;
+select @@global.example_ulong_var;
+
+set session sql_mode=@old_sql_mode;
+
+# finally, show that conditions that already raised an error are not
+# adversely affected (error was already sent, do nothing)
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+set session old=bla;
+
+UNINSTALL PLUGIN example;

sql/set_var.cc

@@ -123,7 +123,8 @@ 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);
+bool throw_bounds_warning(THD *thd, bool fixed, bool unsignd,
+                          const char *name, longlong val);
 static KEY_CACHE *create_key_cache(const char *name, uint length);
 void fix_sql_mode_var(THD *thd, enum_var_type type);
 static uchar *get_error_count(THD *thd);
@@ -1106,13 +1107,29 @@ static void fix_server_id(THD *thd, enum_var_type type)
 }
 
 
-static void throw_bounds_warning(THD *thd, const char *name, ulonglong num)
+bool throw_bounds_warning(THD *thd, bool fixed, bool unsignd,
+                          const char *name, longlong val)
 {
-  char buf[22];
-  push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                      ER_TRUNCATED_WRONG_VALUE,
-                      ER(ER_TRUNCATED_WRONG_VALUE), name,
-                      ullstr(num, buf));
+  if (fixed)
+  {
+    char buf[22];
+
+    if (unsignd)
+      ullstr((ulonglong) val, buf);
+    else
+      llstr(val, buf);
+
+    if (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES)
+    {
+      my_error(ER_WRONG_VALUE_FOR_VAR, MYF(0), name, buf);
+      return TRUE;
+    }
+
+    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                        ER_TRUNCATED_WRONG_VALUE,
+                        ER(ER_TRUNCATED_WRONG_VALUE), name, buf);
+  }
+  return FALSE;
 }
 
 static ulonglong fix_unsigned(THD *thd, ulonglong num,
@@ -1121,8 +1138,7 @@ static ulonglong fix_unsigned(THD *thd, ulonglong num,
   bool fixed= FALSE;
   ulonglong out= getopt_ull_limit_value(num, option_limits, &fixed);
 
-  if (fixed)
-    throw_bounds_warning(thd, option_limits->name, num);
+  throw_bounds_warning(thd, fixed, TRUE, option_limits->name, (longlong) num);
   return out;
 }
 
@@ -1165,7 +1181,8 @@ bool sys_var_long_ptr_global::update(THD *thd, set_var *var)
     if (tmp > ULONG_MAX)
     {
       tmp= ULONG_MAX;
-      throw_bounds_warning(thd, name, var->save_result.ulonglong_value);
+      throw_bounds_warning(thd, TRUE, TRUE, name,
+                           (longlong) var->save_result.ulonglong_value);
     }
 #endif
     *value= (ulong) tmp;
@@ -1250,7 +1267,7 @@ bool sys_var_thd_ulong::update(THD *thd, set_var *var)
   /* Don't use bigger value than given with --maximum-variable-name=.. */
   if ((ulong) tmp > max_system_variables.*offset)
   {
-    throw_bounds_warning(thd, name, tmp);
+    throw_bounds_warning(thd, TRUE, TRUE, name, (longlong) tmp);
     tmp= max_system_variables.*offset;
   }
 
@@ -1260,7 +1277,7 @@ bool sys_var_thd_ulong::update(THD *thd, set_var *var)
   else if (tmp > ULONG_MAX)
   {
     tmp= ULONG_MAX;
-    throw_bounds_warning(thd, name, var->save_result.ulonglong_value);
+    throw_bounds_warning(thd, TRUE, TRUE, name, (longlong) var->save_result.ulonglong_value);
   }
 #endif
 

sql/sql_parse.cc

@@ -3185,6 +3185,18 @@ mysql_execute_command(THD *thd)
       thd->one_shot_set|= lex->one_shot_set;
       send_ok(thd);
     }
+    else
+    {
+      /*
+        We encountered some sort of error, but no message was sent.
+        Send something semi-generic here since we don't know which
+        assignment in the list caused the error.
+      */
+      if (!thd->is_error())
+        my_error(ER_WRONG_ARGUMENTS,MYF(0),"SET");
+      goto error;
+    }
+
     break;
   }
 

sql/sql_plugin.cc

@@ -210,6 +210,8 @@ static void reap_plugins(void);
 
 /* declared in set_var.cc */
 extern sys_var *intern_find_sys_var(const char *str, uint length, bool no_error);
+extern bool throw_bounds_warning(THD *thd, bool fixed, bool unsignd,
+                                 const char *name, longlong val);
 
 #ifdef EMBEDDED_LIBRARY
 /* declared in sql_base.cc */
@@ -1888,16 +1890,8 @@ static int check_func_int(THD *thd, struct st_mysql_sys_var *var,
   else
     *(int *)save= (int) getopt_ll_limit_value(tmp, &options, &fixed);
 
-  if (fixed)
-  {
-    char buf[22];
-    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                        ER_TRUNCATED_WRONG_VALUE,
-                        ER(ER_TRUNCATED_WRONG_VALUE), var->name,
-                        ullstr(tmp, buf));
-  }
-  return (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES) &&
-         (*(int *)save != (int) tmp);
+  return throw_bounds_warning(thd, fixed, var->flags & PLUGIN_VAR_UNSIGNED,
+                              var->name, (longlong) tmp);
 }
 
 
@@ -1916,16 +1910,8 @@ static int check_func_long(THD *thd, struct st_mysql_sys_var *var,
   else
     *(long *)save= (long) getopt_ll_limit_value(tmp, &options, &fixed);
 
-  if (fixed)
-  {
-    char buf[22];
-    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                        ER_TRUNCATED_WRONG_VALUE,
-                        ER(ER_TRUNCATED_WRONG_VALUE), var->name,
-                        ullstr(tmp, buf));
-  }
-  return (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES) &&
-         (*(long *)save != (long) tmp);
+  return throw_bounds_warning(thd, fixed, var->flags & PLUGIN_VAR_UNSIGNED,
+                              var->name, (longlong) tmp);
 }
 
 
@@ -1937,7 +1923,6 @@ static int check_func_longlong(THD *thd, struct st_mysql_sys_var *var,
   struct my_option options;
   value->val_int(value, &tmp);
   plugin_opt_set_limits(&options, var);
-  *(ulonglong *)save= getopt_ull_limit_value(tmp, &options, &fixed);
 
   if (var->flags & PLUGIN_VAR_UNSIGNED)
     *(ulonglong *)save= getopt_ull_limit_value((ulonglong) tmp, &options,
@@ -1945,16 +1930,8 @@ static int check_func_longlong(THD *thd, struct st_mysql_sys_var *var,
   else
     *(longlong *)save= getopt_ll_limit_value(tmp, &options, &fixed);
 
-  if (fixed)
-  {
-    char buf[22];
-    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
-                        ER_TRUNCATED_WRONG_VALUE,
-                        ER(ER_TRUNCATED_WRONG_VALUE), var->name,
-                        ullstr(tmp, buf));
-  }
-  return (thd->variables.sql_mode & MODE_STRICT_ALL_TABLES) &&
-         (*(long long *)save != tmp);
+  return throw_bounds_warning(thd, fixed, var->flags & PLUGIN_VAR_UNSIGNED,
+                              var->name, (longlong) tmp);
 }
 
 static int check_func_str(THD *thd, struct st_mysql_sys_var *var,

storage/example/ha_example.cc

@@ -849,6 +849,7 @@ struct st_mysql_storage_engine example_storage_engine=
 { MYSQL_HANDLERTON_INTERFACE_VERSION };
 
 static ulong srv_enum_var= 0;
+static ulong srv_ulong_var= 0;
 
 const char *enum_var_names[]=
 {
@@ -871,8 +872,21 @@ static MYSQL_SYSVAR_ENUM(
   0,                              // def
   &enum_var_typelib);             // typelib
 
+static MYSQL_SYSVAR_ULONG(
+  ulong_var,
+  srv_ulong_var,
+  PLUGIN_VAR_RQCMDARG,
+  "0..1000",
+  NULL,
+  NULL,
+  8,
+  0,
+  1000,
+  0);
+
 static struct st_mysql_sys_var* example_system_variables[]= {
   MYSQL_SYSVAR(enum_var),
+  MYSQL_SYSVAR(ulong_var),
   NULL
 };