1 files changed, 136 insertions, 0 deletions
diff --git a/defpager/defpager.c b/defpager/defpager.c
new file mode 100644
index 00000000..3a824cf1
--- /dev/null
+++ b/defpager/defpager.c
@@ -0,0 +1,136 @@
+/* Default pager for GNU Hurd.
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   Written by Thomas Bushnell, n/BSG.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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, or (at
+   your option) any later version.
+
+   The GNU Hurd 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 <hurd/pager.h>
+#include <hurd/store.h>
+
+struct user_pager_info 
+{
+  /* Size of the object */
+  vm_size_t size;
+
+  /* One entry for each page of the object. */
+  off_t *map;
+};
+
+/* Expand the P->map as necessary to handle an incoming request of the
+   page at ADDR. */
+static inline void
+expand_map (struct user_pager_info *p, vm_offset_t addr)
+{
+  /* See if this is beyond the current extent */
+  if (page >= pager->size)
+    {
+      off_t *newmap;
+      vm_size_t newsize;
+
+      newsize = page + vm_page_size;
+      newmap = realloc (pager->map, size / vm_page_size * sizeof (off_t));
+
+      bzero (pager->map + pager->size / vm_page_size * sizeof (off_t),
+	     (newsize - pager->size) / vm_page_size * sizeof (off_t));
+      pager->size = newsize;
+      pager->map = newmap;
+    }
+}
+
+error_t
+pager_read_page (struct user_pager_info *pager,
+		 vm_offset_t page,
+		 vm_address_t *buf,
+		 int *write_lock)
+{
+  int pfn = page / vm_page_size;
+  size_t nread;
+  
+  /* We never request write locks. */
+  *write_lock = 0;
+
+  expand_map (pager, page);
+
+  if (!pager->map[pfn])
+    vm_allocate (mach_task_self (), buf, vm_page_size, 1);
+  else
+    {
+      store_read (backing_store, pager->map[pfn], vm_page_size, 
+		  (void **)buf, &nread);
+      if (nread != vm_page_size)
+	{
+	  munmap ((caddr_t) *buf, nread);
+	  return EIO;
+	}
+    }
+  return 0;
+}
+
+      
+error_t
+pager_write_page (struct user_pager_info *pager,
+		  vm_offset_t page,
+		  vm_address_t buf)
+{
+  int pfn = page / vm_page_size;
+  size_t nwritten;
+  
+  expand_map (pager, page);
+  
+  if (!pager->map[pfn])
+    pager->map[pfn] = allocate_backing_page ();
+  
+  /* No more backing store.  Oh dear. */
+  if (!pager->map[pfn])
+    return EIO;
+  
+  err = store_write (backing_store, pager->map[pfn], (void *) buf, 
+		     vm_page_size, &nwritten);
+  if (!err && nwritten != vm_page_size)
+    err = EIO;
+  return err;
+}
+
+error_t
+pager_unlock_page (struct user_pager_info *pager,
+		   vm_offset_t address)
+{
+  return 0;
+}
+
+error_t
+pager_report_extent (struct user_pager_info *pager,
+		     vm_address_t *offset,
+		     vm_size_t *size)
+{
+  *offset = 0;
+  *size = pager->size;
+  return 0;
+}
+
+void
+pager_clear_user_data (struct user_pager_info *pager)
+{
+  return_backing_pages (pager->map, pager->size / vm_page_size);
+  free (pager->map);
+}
+
+void
+pager_dropweak (struct user_pager_info *pager)
+{
+}