New memory malloc malloc library, based on GNU malloc.

1 files changed, 71 insertions, 0 deletions

diff --git a/mmalloc/detach.c b/mmalloc/detach.c
new file mode 100644
index 0000000..69661bc
--- /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 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; either version 2 of the License, or
+(at your option) any later version.
+
+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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+
+#include <fcntl.h>
+#include "mmalloc.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)
+  void *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.top)) == NULL)
+	{
+	  /* Update the original malloc descriptor with any changes */
+	  *(struct mdesc *) md = mtemp;
+	}
+      else
+	{
+	  if (mtemp.flags & MMALLOC_DEVZERO)
+	    {
+	      (void) close (mtemp.fd);
+	    }
+	  md = NULL;
+	}
+    }
+
+  return (md);
+}
+
+
+