1 files changed, 101 insertions, 0 deletions
diff --git a/mysys/my_lockmem.c b/mysys/my_lockmem.c
new file mode 100644
index 00000000..45f16bac
--- /dev/null
+++ b/mysys/my_lockmem.c
@@ -0,0 +1,101 @@
+/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2022, MariaDB Corporation.
+
+   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 02110-1335  USA */
+
+/* Alloc a block of locked memory (memory protected against swap) */
+
+#include "mysys_priv.h"
+#include "mysys_err.h"
+#include "aligned.h"
+#include <my_list.h>
+
+#ifdef HAVE_MLOCK
+
+struct st_mem_list
+{
+  LIST list;
+  uchar *page;
+  uint size;
+};
+
+LIST *mem_list;
+
+uchar *my_malloc_lock(size_t size, myf MyFlags)
+{
+  int success;
+  uint pagesize= my_system_page_size;
+  uchar *ptr;
+  struct st_mem_list *element;
+  DBUG_ENTER("my_malloc_lock");
+
+  size=((size-1) & ~(pagesize-1))+pagesize;
+  if (!(ptr=aligned_malloc(size,pagesize)))
+  {
+    if (MyFlags & (MY_FAE+MY_WME))
+      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_FATAL), size);
+    DBUG_RETURN(0);
+  }
+  success = mlock((uchar*) ptr,size);
+  if (success != 0 && geteuid() == 0)
+  {
+    DBUG_PRINT("warning",("Failed to lock memory. errno %d\n",
+			  errno));
+    fprintf(stderr, "Warning: Failed to lock memory. errno %d\n",
+	    errno);
+  }
+  else
+  {
+    /* Add block in a list for munlock */
+    if (!(element=(struct st_mem_list*) my_malloc(sizeof(*element),MyFlags)))
+    {
+      (void) munlock((uchar*) ptr,size);
+      free(ptr);
+      DBUG_RETURN(0);
+    }
+    element->list.data=(uchar*) element;
+    element->page=ptr;
+    element->size=size;
+    mysql_mutex_lock(&THR_LOCK_malloc);
+    mem_list=list_add(mem_list,&element->list);
+    mysql_mutex_unlock(&THR_LOCK_malloc);
+    update_malloc_size((longlong) size, 0);
+  }
+  DBUG_RETURN(ptr);
+}
+
+
+void my_free_lock(uchar *ptr)
+{
+  LIST *list;
+  struct st_mem_list *element=0;
+
+  mysql_mutex_lock(&THR_LOCK_malloc);
+  for (list=mem_list ; list ; list=list->next)
+  {
+    element=(struct st_mem_list*) list->data;
+    if (ptr == element->page)
+    {						/* Found locked mem */
+      (void) munlock((uchar*) ptr,element->size);
+      mem_list=list_delete(mem_list,list);
+      update_malloc_size(- (longlong) element->size, 0);
+      break;
+    }
+  }
+  mysql_mutex_unlock(&THR_LOCK_malloc);
+  my_free(element);
+  aligned_free(ptr);				/* Free even if not locked */
+}
+
+#endif /* HAVE_MLOCK */