[PATCH 2/2] virtio: console: Disable lseek(2) for port file operations

Amit Shah
2010-09-16T09:13:09Z

The ports are char devices; do not have seeking capabilities.  Calling
nonseekable_open() from the fops_open() call and setting the llseek fops
pointer to no_llseek ensures an lseek() call from userspace returns
-ESPIPE.

Signed-off-by: Amit Shah <amit.shah at redhat.com>
CC: Arnd Bergmann <arnd at arndb.de>
---
 drivers/char/virtio_console.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 2dbcd41..28718a9 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -798,6 +798,8 @@ static int port_fops_open(struct inode *inode, struct file
*filp)
 	reclaim_consumed_buffers(port);
 	spin_unlock_irq(&port->outvq_lock);

+	nonseekable_open(inode, filp);
+
 	/* Notify host of port being opened */
 	send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);

@@ -829,6 +831,7 @@ static const struct file_operations port_fops = {
 	.poll  = port_fops_poll,
 	.release = port_fops_release,
 	.fasync = port_fops_fasync,
+	.llseek = no_llseek,
 };

 /*
--
1.7.2.3