Bug#11761576 54082: HANDLE_SEGFAULT MAKES USE OF UNSAFE FUNCTIONS

handle_segfault is the signal handler code of mysqld.  however, it makes
calls to potentially unsafe functions localtime_r, fprintf, fflush.

1 files changed, 73 insertions, 0 deletions

diff --git a/sql/sys_vars.cc b/sql/sys_vars.cc
index 7a04015dc93..65cc4d4c4ab 100644
--- a/sql/sys_vars.cc
+++ b/sql/sys_vars.cc
@@ -49,6 +49,8 @@
 #include "../storage/perfschema/pfs_server.h"
 #endif /* WITH_PERFSCHEMA_STORAGE_ENGINE */
 
+TYPELIB bool_typelib={ array_elements(bool_values)-1, "", bool_values, 0 };
+
 /*
   This forward declaration is needed because including sql_base.h
   causes further includes.  [TODO] Eliminate this forward declaration
@@ -56,6 +58,77 @@
 */
 extern void close_thread_tables(THD *thd);
 
+
+static bool update_buffer_size(THD *thd, KEY_CACHE *key_cache,
+                               ptrdiff_t offset, ulonglong new_value)
+{
+  bool error= false;
+  DBUG_ASSERT(offset == offsetof(KEY_CACHE, param_buff_size));
+
+  if (new_value == 0)
+  {
+    if (key_cache == dflt_key_cache)
+    {
+      my_error(ER_WARN_CANT_DROP_DEFAULT_KEYCACHE, MYF(0));
+      return true;
+    }
+
+    if (key_cache->key_cache_inited)            // If initied
+    {
+      /*
+        Move tables using this key cache to the default key cache
+        and clear the old key cache.
+      */
+      key_cache->in_init= 1;
+      mysql_mutex_unlock(&LOCK_global_system_variables);
+      key_cache->param_buff_size= 0;
+      ha_resize_key_cache(key_cache);
+      ha_change_key_cache(key_cache, dflt_key_cache);
+      /*
+        We don't delete the key cache as some running threads my still be in
+        the key cache code with a pointer to the deleted (empty) key cache
+      */
+      mysql_mutex_lock(&LOCK_global_system_variables);
+      key_cache->in_init= 0;
+    }
+    return error;
+  }
+
+  key_cache->param_buff_size= new_value;
+
+  /* If key cache didn't exist initialize it, else resize it */
+  key_cache->in_init= 1;
+  mysql_mutex_unlock(&LOCK_global_system_variables);
+
+  if (!key_cache->key_cache_inited)
+    error= ha_init_key_cache(0, key_cache);
+  else
+    error= ha_resize_key_cache(key_cache);
+
+  mysql_mutex_lock(&LOCK_global_system_variables);
+  key_cache->in_init= 0;
+
+  return error;
+}
+
+static bool update_keycache_param(THD *thd, KEY_CACHE *key_cache,
+                                  ptrdiff_t offset, ulonglong new_value)
+{
+  bool error= false;
+  DBUG_ASSERT(offset != offsetof(KEY_CACHE, param_buff_size));
+
+  keycache_var(key_cache, offset)= new_value;
+
+  key_cache->in_init= 1;
+  mysql_mutex_unlock(&LOCK_global_system_variables);
+  error= ha_resize_key_cache(key_cache);
+
+  mysql_mutex_lock(&LOCK_global_system_variables);
+  key_cache->in_init= 0;
+
+  return error;
+}
+
 /*
   The rule for this file: everything should be 'static'. When a sys_var
   variable or a function from this file is - in very rare cases - needed