Initial revision

1 files changed, 103 insertions, 0 deletions

diff --git a/libdiskfs/rdwr-internal.c b/libdiskfs/rdwr-internal.c
new file mode 100644
index 00000000..b8f23c67
--- /dev/null
+++ b/libdiskfs/rdwr-internal.c
@@ -0,0 +1,103 @@
+/* 
+   Copyright (C) 1994 Free Software Foundation
+
+   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, 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 "priv.h"
+
+/* Actually read or write a file.  The file size must already permit
+   the requested access.  NP is the file to read/write.  DATA is a buffer
+   to write from or fill on read.  OFFSET is the absolute address (-1
+   not permitted here); AMT is the size of the read/write to perform;
+   DIR is set for writing and clear for reading.  The inode must
+   be locked.  */
+static error_t
+io_rdwr (struct inode *np,
+	 char *data,
+	 int offset, 
+	 int amt, 
+	 int dir)
+{
+  char *window;
+  int winoff;
+  int cc;
+  memory_object_t memobj;
+  int err;
+
+  if (dir)
+    assert (!readonly);
+
+  if (!readonly)
+    {
+      if (!(err = catch_exception ()))
+	{
+	  if (dir)
+	    np->di->di_mtime = wallclock->seconds;
+	  else
+	    np->di->di_atime = wallclock->seconds;
+	  end_catch_exception ();
+	}
+      else
+	return err;
+    }
+  else
+    err = 0;
+  
+  memobj = get_filemap (np);
+  mach_port_insert_right (mach_task_self (), memobj, memobj,
+			  MACH_MSG_TYPE_MAKE_SEND);
+  
+  while (amt > 0)
+    {
+      winoff = trunc_page (offset);
+
+      window = 0;
+      /* We map in 8 pages at a time.  Where'd that come from?  Well, the
+	 vax has a 1024 pagesize and with 8k blocks that seems like a
+	 reasonable number. */
+      err = vm_map (mach_task_self (), (u_int *)&window, 8 * __vm_page_size, 
+		    0, 1, memobj, winoff, 0, VM_PROT_READ|VM_PROT_WRITE, 
+		    VM_PROT_READ|VM_PROT_WRITE, VM_INHERIT_NONE);
+      assert (!err);
+      register_memory_fault_area (get_filemap_pager_struct (np), winoff,
+				  window, 8 * __vm_page_size);
+      
+      if ((offset - winoff) + amt > 8 * __vm_page_size)
+	cc = 8 * __vm_page_size - (offset - winoff);
+      else
+	cc = amt;
+      
+      if (!(err = catch_exception ()))
+	{
+	  if (dir)
+	    bcopy (data, window + (offset - winoff), cc);
+	  else
+	    bcopy (window + (offset - winoff), data, cc);
+	  end_catch_exception ();
+	}
+
+      vm_deallocate (mach_task_self (), (u_int) window, 8 * __vm_page_size);
+      unregister_memory_fault_area (window, 8 * __vm_page_size);
+      if (err)
+	break;
+      amt -= cc;
+      offset += cc;
+      data += cc;
+    }
+  assert (amt == 0 || err);
+
+  mach_port_deallocate (mach_task_self (), memobj);
+  return err;
+}