mmalloc from last version to be included in gdb.

[ocaml-ancient.git] / mmalloc / detach.c

diff --git a/mmalloc/detach.c b/mmalloc/detach.c
new file mode 100644 (file)
index 0000000..1780679
--- /dev/null
+++ b/mmalloc/detach.c
@@ -0,0 +1,71 @@
+/* Finish access to a mmap'd malloc managed region.
+   Copyright 1992 Free Software Foundation, Inc.
+
+   Contributed by Fred Fish at Cygnus Support.   fnf@cygnus.com
+
+This file is part of the GNU C Library.
+
+The GNU C 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.
+
+The GNU C 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 the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+#include <sys/types.h>
+#include "mmprivate.h"
+
+/* Terminate access to a mmalloc managed region by unmapping all memory pages
+   associated with the region, and closing the file descriptor if it is one
+   that we opened.
+
+   Returns NULL on success.
+
+   Returns the malloc descriptor on failure, which can subsequently be used
+   for further action, such as obtaining more information about the nature of
+   the failure by examining the preserved errno value.
+
+   Note that the malloc descriptor that we are using is currently located in
+   region we are about to unmap, so we first make a local copy of it on the
+   stack and use the copy. */
+
+PTR
+mmalloc_detach (md)
+     PTR md;
+{
+  struct mdesc mtemp;
+
+  if (md != NULL)
+    {
+
+      mtemp = *(struct mdesc *) md;
+      
+      /* Now unmap all the pages associated with this region by asking for a
+        negative increment equal to the current size of the region. */
+      
+      if ((mtemp.morecore (&mtemp, mtemp.base - mtemp.breakval)) == NULL)
+       {
+         /* Deallocating failed.  Update the original malloc descriptor
+            with any changes */
+         *(struct mdesc *) md = mtemp;
+       }
+      else
+       {
+         if (mtemp.flags & MMALLOC_DEVZERO)
+           {
+             close (mtemp.fd);
+           }
+         md = NULL;
+       }
+    }
+
+  return (md);
+}