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authorPeter Hurley <peter@hurleysoftware.com>2016-01-10 08:45:10 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-28 22:58:02 +0300
commitf557474ca3a23800dffb790846bcb121fa046c71 (patch)
tree0a77a92c9d977bc31a35567afab4c2a268eb6436 /drivers/tty/tty_io.c
parentbee6741ca022f051ea1b46e16fb2ff0097643181 (diff)
downloadlinux-f557474ca3a23800dffb790846bcb121fa046c71.tar.xz
tty: Add fasync() hung up file operation
VFS uses a two-stage check-and-call method for invoking file_operations methods, without explicitly snapshotting either the file_operations ptr or the function ptr. Since the tty core is one of the few VFS users that changes the f_op file_operations ptr of the file descriptor (when the tty has been hung up), and since the likelihood of the compiler generating a reload of either f_op or the function ptr is basically nil, just define a hung up fasync() file operation that returns an error. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_io.c')
-rw-r--r--drivers/tty/tty_io.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 7533ab1abe72..0140c8669ada 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -468,6 +468,11 @@ static long hung_up_tty_compat_ioctl(struct file *file,
return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
}
+static int hung_up_tty_fasync(int fd, struct file *file, int on)
+{
+ return -ENOTTY;
+}
+
static const struct file_operations tty_fops = {
.llseek = no_llseek,
.read = tty_read,
@@ -500,6 +505,7 @@ static const struct file_operations hung_up_tty_fops = {
.unlocked_ioctl = hung_up_tty_ioctl,
.compat_ioctl = hung_up_tty_compat_ioctl,
.release = tty_release,
+ .fasync = hung_up_tty_fasync,
};
static DEFINE_SPINLOCK(redirect_lock);