Initial revision

1 files changed, 85 insertions, 0 deletions

diff --git a/libdiskfs/io-read.c b/libdiskfs/io-read.c
new file mode 100644
index 00000000..e6623457
--- /dev/null
+++ b/libdiskfs/io-read.c
@@ -0,0 +1,85 @@
+/* 
+   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"
+
+/* Implement io_read as described in <hurd/io.defs>. */
+error_t
+diskfs_S_io_read (struct protid *cred,
+		  char **data,
+		  unsigned int *datalen,
+		  off_t offset,
+		  int maxread)
+{
+  struct node *np;
+  int err;
+  int off = offset;
+  char *buf;
+  int ourbuf = 0;
+
+  if (!cred)
+    return EOPNOTSUPP;
+  
+  np = cred->po->np;
+  if (!(cred->po->openstat & O_READ))
+    return EBADF;
+  if (maxread < 0)
+    return EINVAL;
+  
+  mutex_lock (&np->i_toplock);
+
+  if (err = ioserver_get_conch (&np->i_conch))
+    {
+      mutex_unlock (&np->i_toplock);
+      return err;
+    }
+  
+  if (off == -1)
+    off = cred->po->filepointer;
+  
+  if (!(err = catch_exception ()))
+    {
+      if (off + maxread > np->di->di_size)
+	maxread = np->di->di_size - off;
+      end_catch_exception ();
+    }
+  
+  if (!err)
+    {
+      if (maxread > *datalen)
+	{
+	  ourbuf = 1;
+	  vm_allocate (mach_task_self (), (u_int *) &buf, maxread, 1);
+	  *data = buf;
+	}
+      else
+	buf = *data;
+
+      *datalen = maxread;
+      if (maxread)
+	err = io_rdwr (np, buf, off, maxread, 0);
+      else
+	err = 0;
+      if (offset == -1 && !err)
+	cred->po->filepointer += *datalen;
+      if (err && ourbuf)
+	vm_deallocate (mach_task_self (), (u_int) buf, maxread);
+    }
+  
+  mutex_unlock (&np->i_toplock);
+  return err;
+}