1 files changed, 101 insertions, 0 deletions
diff --git a/mysys/my_lockmem.c b/mysys/my_lockmem.c
new file mode 100644
index 00000000000..9c77c885797
--- /dev/null
+++ b/mysys/my_lockmem.c
@@ -0,0 +1,101 @@
+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+   
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public
+   License as published by the Free Software Foundation; either
+   version 2 of the License, or (at your option) any later version.
+   
+   This library 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
+   Library General Public License for more details.
+   
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+   MA 02111-1307, USA */
+
+/* Alloc a block of locked memory */
+
+#include "mysys_priv.h"
+#include "mysys_err.h"
+#include <my_list.h>
+
+#ifdef HAVE_MLOCK
+#include <sys/mman.h>
+
+struct st_mem_list
+{
+  LIST list;
+  byte *page;
+  uint size;
+};
+
+LIST *mem_list;
+
+byte *my_malloc_lock(uint size,myf MyFlags)
+{
+  int success;
+  uint pagesize=sysconf(_SC_PAGESIZE);
+  byte *ptr;
+  struct st_mem_list *element;
+  DBUG_ENTER("my_malloc_lock");
+
+  size=((size-1) & ~(pagesize-1))+pagesize;
+  if (!(ptr=memalign(pagesize,size)))
+  {
+    if (MyFlags & (MY_FAE+MY_WME))
+      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG),size);
+    DBUG_RETURN(0);
+  }
+  success = mlock((byte*) 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((byte*) ptr,size));
+      free(ptr);
+      DBUG_RETURN(0);
+    }
+    element->list.data=(byte*) element;
+    element->page=ptr;
+    element->size=size;
+    pthread_mutex_lock(&THR_LOCK_malloc);
+    mem_list=list_add(mem_list,&element->list);
+    pthread_mutex_unlock(&THR_LOCK_malloc);
+  }
+  DBUG_RETURN(ptr);
+}
+
+
+void my_free_lock(byte *ptr,myf Myflags __attribute__((unused)))
+{
+  LIST *list;
+  struct st_mem_list *element=0;
+
+  pthread_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((byte*) ptr,element->size));
+      mem_list=list_delete(mem_list,list);
+      break;
+    }
+  }
+  pthread_mutex_unlock(&THR_LOCK_malloc);
+  if (element)
+    my_free((gptr) element,MYF(0));
+  free(ptr);					/* Free even if not locked */
+}
+
+#endif /* HAVE_MLOCK */