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authorhyc@symas.com <hyc@symas.com>2010-06-22 10:14:49 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-10 13:47:39 -0700
commit26df6d13406d1a53b0bda08bd712f1924affd7cd (patch)
treedb17328acbd7cac9dc20bc854509527c1c89ca01 /drivers/char/pty.c
parenta3c8ed693da9782f924223f65da9261da796e49b (diff)
tty: Add EXTPROC support for LINEMODE
This patch is against the 2.6.34 source. Paraphrased from the 1989 BSD patch by David Borman @ cray.com: These are the changes needed for the kernel to support LINEMODE in the server. There is a new bit in the termios local flag word, EXTPROC. When this bit is set, several aspects of the terminal driver are disabled. Input line editing, character echo, and mapping of signals are all disabled. This allows the telnetd to turn off these functions when in linemode, but still keep track of what state the user wants the terminal to be in. New ioctl: TIOCSIG Generate a signal to processes in the current process group of the pty. There is a new mode for packet driver, the TIOCPKT_IOCTL bit. When packet mode is turned on in the pty, and the EXTPROC bit is set, then whenever the state of the pty is changed, the next read on the master side of the pty will have the TIOCPKT_IOCTL bit set. This allows the process on the server side of the pty to know when the state of the terminal has changed; it can then issue the appropriate ioctl to retrieve the new state. Since the original BSD patches accompanied the source code for telnet I've left that reference here, but obviously the feature is useful for any remote terminal protocol, including ssh. The corresponding feature has existed in the BSD tty driver since 1989. For historical reference, a good copy of the relevant files can be found here: http://anonsvn.mit.edu/viewvc/krb5/trunk/src/appl/telnet/?pathrev=17741 Signed-off-by: Howard Chu <hyc@symas.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/char/pty.c')
-rw-r--r--drivers/char/pty.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index d83a43130df..b640ef29be1 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -171,6 +171,23 @@ static int pty_set_lock(struct tty_struct *tty, int __user *arg)
return 0;
}
+/* Send a signal to the slave */
+static int pty_signal(struct tty_struct *tty, int sig)
+{
+ unsigned long flags;
+ struct pid *pgrp;
+
+ if (tty->link) {
+ spin_lock_irqsave(&tty->link->ctrl_lock, flags);
+ pgrp = get_pid(tty->link->pgrp);
+ spin_unlock_irqrestore(&tty->link->ctrl_lock, flags);
+
+ kill_pgrp(pgrp, sig, 1);
+ put_pid(pgrp);
+ }
+ return 0;
+}
+
static void pty_flush_buffer(struct tty_struct *tty)
{
struct tty_struct *to = tty->link;
@@ -321,6 +338,8 @@ static int pty_bsd_ioctl(struct tty_struct *tty, struct file *file,
switch (cmd) {
case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
return pty_set_lock(tty, (int __user *) arg);
+ case TIOCSIG: /* Send signal to other side of pty */
+ return pty_signal(tty, (int) arg);
}
return -ENOIOCTLCMD;
}
@@ -476,6 +495,8 @@ static int pty_unix98_ioctl(struct tty_struct *tty, struct file *file,
return pty_set_lock(tty, (int __user *)arg);
case TIOCGPTN: /* Get PT Number */
return put_user(tty->index, (unsigned int __user *)arg);
+ case TIOCSIG: /* Send signal to other side of pty */
+ return pty_signal(tty, (int) arg);
}
return -ENOIOCTLCMD;