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![Linus Torvalds](/assets/img/avatar_default.png)
This is more prep-work for the upcoming pty changes. Still just code cleanup with no actual semantic changes. This removes a bunch pointless complexity by just having the slave pty side remember the dentry associated with the devpts slave rather than the inode. That allows us to remove all the "look up the dentry" code for when we want to remove it again. Together with moving the tty pointer from "inode->i_private" to "dentry->d_fsdata" and getting rid of pointless inode locking, this removes about 30 lines of code. Not only is the end result smaller, it's simpler and easier to understand. The old code, for example, depended on the d_find_alias() to not just find the dentry, but also to check that it is still hashed, which in turn validated the tty pointer in the inode. That is a _very_ roundabout way to say "invalidate the cached tty pointer when the dentry is removed". The new code just does dentry->d_fsdata = NULL; in devpts_pty_kill() instead, invalidating the tty pointer rather more directly and obviously. Don't do something complex and subtle when the obvious straightforward approach will do. The rest of the patch (ie apart from code deletion and the above tty pointer clearing) is just switching the calling convention to pass the dentry or file pointer around instead of the inode. Cc: Eric Biederman <ebiederm@xmission.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Jann Horn <jann@thejh.net> Cc: Greg KH <greg@kroah.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Florian Weimer <fw@deneb.enyo.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
877 lines
22 KiB
C
877 lines
22 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Added support for a Unix98-style ptmx device.
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* -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
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*
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <linux/fcntl.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <linux/major.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/uaccess.h>
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#include <linux/bitops.h>
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#include <linux/devpts_fs.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/poll.h>
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#undef TTY_DEBUG_HANGUP
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#ifdef TTY_DEBUG_HANGUP
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# define tty_debug_hangup(tty, f, args...) tty_debug(tty, f, ##args)
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#else
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# define tty_debug_hangup(tty, f, args...) do {} while (0)
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#endif
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#ifdef CONFIG_UNIX98_PTYS
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static struct tty_driver *ptm_driver;
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static struct tty_driver *pts_driver;
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static DEFINE_MUTEX(devpts_mutex);
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#endif
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static void pty_close(struct tty_struct *tty, struct file *filp)
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{
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BUG_ON(!tty);
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if (tty->driver->subtype == PTY_TYPE_MASTER)
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WARN_ON(tty->count > 1);
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else {
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if (test_bit(TTY_IO_ERROR, &tty->flags))
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return;
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if (tty->count > 2)
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return;
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}
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set_bit(TTY_IO_ERROR, &tty->flags);
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wake_up_interruptible(&tty->read_wait);
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wake_up_interruptible(&tty->write_wait);
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spin_lock_irq(&tty->ctrl_lock);
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tty->packet = 0;
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spin_unlock_irq(&tty->ctrl_lock);
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/* Review - krefs on tty_link ?? */
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if (!tty->link)
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return;
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set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
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tty_flip_buffer_push(tty->link->port);
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wake_up_interruptible(&tty->link->write_wait);
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if (tty->driver->subtype == PTY_TYPE_MASTER) {
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set_bit(TTY_OTHER_CLOSED, &tty->flags);
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#ifdef CONFIG_UNIX98_PTYS
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if (tty->driver == ptm_driver) {
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mutex_lock(&devpts_mutex);
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if (tty->link->driver_data)
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devpts_pty_kill(tty->link->driver_data);
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mutex_unlock(&devpts_mutex);
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}
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#endif
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tty_vhangup(tty->link);
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}
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}
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/*
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* The unthrottle routine is called by the line discipline to signal
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* that it can receive more characters. For PTY's, the TTY_THROTTLED
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* flag is always set, to force the line discipline to always call the
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* unthrottle routine when there are fewer than TTY_THRESHOLD_UNTHROTTLE
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* characters in the queue. This is necessary since each time this
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* happens, we need to wake up any sleeping processes that could be
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* (1) trying to send data to the pty, or (2) waiting in wait_until_sent()
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* for the pty buffer to be drained.
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*/
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static void pty_unthrottle(struct tty_struct *tty)
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{
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tty_wakeup(tty->link);
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set_bit(TTY_THROTTLED, &tty->flags);
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}
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/**
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* pty_write - write to a pty
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* @tty: the tty we write from
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* @buf: kernel buffer of data
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* @count: bytes to write
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*
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* Our "hardware" write method. Data is coming from the ldisc which
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* may be in a non sleeping state. We simply throw this at the other
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* end of the link as if we were an IRQ handler receiving stuff for
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* the other side of the pty/tty pair.
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*/
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static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
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{
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struct tty_struct *to = tty->link;
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if (tty->stopped)
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return 0;
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if (c > 0) {
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/* Stuff the data into the input queue of the other end */
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c = tty_insert_flip_string(to->port, buf, c);
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/* And shovel */
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if (c)
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tty_flip_buffer_push(to->port);
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}
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return c;
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}
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/**
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* pty_write_room - write space
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* @tty: tty we are writing from
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*
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* Report how many bytes the ldisc can send into the queue for
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* the other device.
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*/
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static int pty_write_room(struct tty_struct *tty)
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{
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if (tty->stopped)
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return 0;
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return tty_buffer_space_avail(tty->link->port);
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}
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/**
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* pty_chars_in_buffer - characters currently in our tx queue
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* @tty: our tty
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*
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* Report how much we have in the transmit queue. As everything is
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* instantly at the other end this is easy to implement.
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*/
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static int pty_chars_in_buffer(struct tty_struct *tty)
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{
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return 0;
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}
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/* Set the lock flag on a pty */
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static int pty_set_lock(struct tty_struct *tty, int __user *arg)
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{
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int val;
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if (get_user(val, arg))
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return -EFAULT;
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if (val)
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set_bit(TTY_PTY_LOCK, &tty->flags);
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else
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clear_bit(TTY_PTY_LOCK, &tty->flags);
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return 0;
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}
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static int pty_get_lock(struct tty_struct *tty, int __user *arg)
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{
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int locked = test_bit(TTY_PTY_LOCK, &tty->flags);
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return put_user(locked, arg);
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}
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/* Set the packet mode on a pty */
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static int pty_set_pktmode(struct tty_struct *tty, int __user *arg)
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{
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int pktmode;
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if (get_user(pktmode, arg))
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return -EFAULT;
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spin_lock_irq(&tty->ctrl_lock);
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if (pktmode) {
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if (!tty->packet) {
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tty->link->ctrl_status = 0;
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smp_mb();
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tty->packet = 1;
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}
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} else
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tty->packet = 0;
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spin_unlock_irq(&tty->ctrl_lock);
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return 0;
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}
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/* Get the packet mode of a pty */
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static int pty_get_pktmode(struct tty_struct *tty, int __user *arg)
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{
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int pktmode = tty->packet;
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return put_user(pktmode, arg);
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}
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/* Send a signal to the slave */
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static int pty_signal(struct tty_struct *tty, int sig)
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{
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struct pid *pgrp;
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if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP)
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return -EINVAL;
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if (tty->link) {
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pgrp = tty_get_pgrp(tty->link);
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if (pgrp)
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kill_pgrp(pgrp, sig, 1);
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put_pid(pgrp);
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}
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return 0;
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}
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static void pty_flush_buffer(struct tty_struct *tty)
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{
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struct tty_struct *to = tty->link;
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struct tty_ldisc *ld;
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if (!to)
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return;
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ld = tty_ldisc_ref(to);
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tty_buffer_flush(to, ld);
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if (ld)
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tty_ldisc_deref(ld);
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if (to->packet) {
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spin_lock_irq(&tty->ctrl_lock);
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tty->ctrl_status |= TIOCPKT_FLUSHWRITE;
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wake_up_interruptible(&to->read_wait);
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spin_unlock_irq(&tty->ctrl_lock);
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}
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}
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static int pty_open(struct tty_struct *tty, struct file *filp)
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{
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if (!tty || !tty->link)
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return -ENODEV;
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if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
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goto out;
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if (test_bit(TTY_PTY_LOCK, &tty->link->flags))
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goto out;
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if (tty->driver->subtype == PTY_TYPE_SLAVE && tty->link->count != 1)
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goto out;
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clear_bit(TTY_IO_ERROR, &tty->flags);
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/* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */
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clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
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clear_bit(TTY_OTHER_DONE, &tty->link->flags);
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set_bit(TTY_THROTTLED, &tty->flags);
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return 0;
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out:
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set_bit(TTY_IO_ERROR, &tty->flags);
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return -EIO;
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}
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static void pty_set_termios(struct tty_struct *tty,
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struct ktermios *old_termios)
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{
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/* See if packet mode change of state. */
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if (tty->link && tty->link->packet) {
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int extproc = (old_termios->c_lflag & EXTPROC) | L_EXTPROC(tty);
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int old_flow = ((old_termios->c_iflag & IXON) &&
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(old_termios->c_cc[VSTOP] == '\023') &&
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(old_termios->c_cc[VSTART] == '\021'));
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int new_flow = (I_IXON(tty) &&
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STOP_CHAR(tty) == '\023' &&
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START_CHAR(tty) == '\021');
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if ((old_flow != new_flow) || extproc) {
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spin_lock_irq(&tty->ctrl_lock);
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if (old_flow != new_flow) {
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tty->ctrl_status &= ~(TIOCPKT_DOSTOP | TIOCPKT_NOSTOP);
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if (new_flow)
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tty->ctrl_status |= TIOCPKT_DOSTOP;
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else
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tty->ctrl_status |= TIOCPKT_NOSTOP;
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}
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if (extproc)
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tty->ctrl_status |= TIOCPKT_IOCTL;
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spin_unlock_irq(&tty->ctrl_lock);
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wake_up_interruptible(&tty->link->read_wait);
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}
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}
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tty->termios.c_cflag &= ~(CSIZE | PARENB);
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tty->termios.c_cflag |= (CS8 | CREAD);
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}
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/**
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* pty_do_resize - resize event
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* @tty: tty being resized
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* @ws: window size being set.
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*
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* Update the termios variables and send the necessary signals to
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* peform a terminal resize correctly
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*/
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static int pty_resize(struct tty_struct *tty, struct winsize *ws)
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{
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struct pid *pgrp, *rpgrp;
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struct tty_struct *pty = tty->link;
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/* For a PTY we need to lock the tty side */
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mutex_lock(&tty->winsize_mutex);
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if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
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goto done;
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/* Signal the foreground process group of both ptys */
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pgrp = tty_get_pgrp(tty);
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rpgrp = tty_get_pgrp(pty);
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if (pgrp)
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kill_pgrp(pgrp, SIGWINCH, 1);
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if (rpgrp != pgrp && rpgrp)
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kill_pgrp(rpgrp, SIGWINCH, 1);
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put_pid(pgrp);
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put_pid(rpgrp);
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tty->winsize = *ws;
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pty->winsize = *ws; /* Never used so will go away soon */
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done:
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mutex_unlock(&tty->winsize_mutex);
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return 0;
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}
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/**
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* pty_start - start() handler
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* pty_stop - stop() handler
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* @tty: tty being flow-controlled
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*
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* Propagates the TIOCPKT status to the master pty.
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*
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* NB: only the master pty can be in packet mode so only the slave
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* needs start()/stop() handlers
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*/
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static void pty_start(struct tty_struct *tty)
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{
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unsigned long flags;
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if (tty->link && tty->link->packet) {
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spin_lock_irqsave(&tty->ctrl_lock, flags);
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tty->ctrl_status &= ~TIOCPKT_STOP;
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tty->ctrl_status |= TIOCPKT_START;
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spin_unlock_irqrestore(&tty->ctrl_lock, flags);
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wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
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}
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}
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static void pty_stop(struct tty_struct *tty)
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{
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unsigned long flags;
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if (tty->link && tty->link->packet) {
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spin_lock_irqsave(&tty->ctrl_lock, flags);
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tty->ctrl_status &= ~TIOCPKT_START;
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tty->ctrl_status |= TIOCPKT_STOP;
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spin_unlock_irqrestore(&tty->ctrl_lock, flags);
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wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
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}
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}
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/**
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* pty_common_install - set up the pty pair
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* @driver: the pty driver
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* @tty: the tty being instantiated
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* @legacy: true if this is BSD style
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*
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* Perform the initial set up for the tty/pty pair. Called from the
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* tty layer when the port is first opened.
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*
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* Locking: the caller must hold the tty_mutex
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*/
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static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
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bool legacy)
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{
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struct tty_struct *o_tty;
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struct tty_port *ports[2];
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int idx = tty->index;
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int retval = -ENOMEM;
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/* Opening the slave first has always returned -EIO */
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if (driver->subtype != PTY_TYPE_MASTER)
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return -EIO;
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ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);
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ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);
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if (!ports[0] || !ports[1])
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goto err;
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if (!try_module_get(driver->other->owner)) {
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/* This cannot in fact currently happen */
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goto err;
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}
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o_tty = alloc_tty_struct(driver->other, idx);
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if (!o_tty)
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goto err_put_module;
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tty_set_lock_subclass(o_tty);
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lockdep_set_subclass(&o_tty->termios_rwsem, TTY_LOCK_SLAVE);
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if (legacy) {
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/* We always use new tty termios data so we can do this
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the easy way .. */
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tty_init_termios(tty);
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tty_init_termios(o_tty);
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driver->other->ttys[idx] = o_tty;
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driver->ttys[idx] = tty;
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} else {
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memset(&tty->termios_locked, 0, sizeof(tty->termios_locked));
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tty->termios = driver->init_termios;
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memset(&o_tty->termios_locked, 0, sizeof(tty->termios_locked));
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o_tty->termios = driver->other->init_termios;
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}
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/*
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* Everything allocated ... set up the o_tty structure.
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*/
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tty_driver_kref_get(driver->other);
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/* Establish the links in both directions */
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tty->link = o_tty;
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o_tty->link = tty;
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tty_port_init(ports[0]);
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tty_port_init(ports[1]);
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tty_buffer_set_limit(ports[0], 8192);
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tty_buffer_set_limit(ports[1], 8192);
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o_tty->port = ports[0];
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tty->port = ports[1];
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o_tty->port->itty = o_tty;
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tty_buffer_set_lock_subclass(o_tty->port);
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tty_driver_kref_get(driver);
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tty->count++;
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o_tty->count++;
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return 0;
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err_put_module:
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module_put(driver->other->owner);
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err:
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kfree(ports[0]);
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kfree(ports[1]);
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return retval;
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}
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static void pty_cleanup(struct tty_struct *tty)
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{
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tty_port_put(tty->port);
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}
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/* Traditional BSD devices */
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#ifdef CONFIG_LEGACY_PTYS
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static int pty_install(struct tty_driver *driver, struct tty_struct *tty)
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{
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return pty_common_install(driver, tty, true);
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}
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static void pty_remove(struct tty_driver *driver, struct tty_struct *tty)
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{
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struct tty_struct *pair = tty->link;
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driver->ttys[tty->index] = NULL;
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if (pair)
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pair->driver->ttys[pair->index] = NULL;
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}
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|
|
static int pty_bsd_ioctl(struct tty_struct *tty,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
switch (cmd) {
|
|
case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
|
|
return pty_set_lock(tty, (int __user *) arg);
|
|
case TIOCGPTLCK: /* Get PT Lock status */
|
|
return pty_get_lock(tty, (int __user *)arg);
|
|
case TIOCPKT: /* Set PT packet mode */
|
|
return pty_set_pktmode(tty, (int __user *)arg);
|
|
case TIOCGPKT: /* Get PT packet mode */
|
|
return pty_get_pktmode(tty, (int __user *)arg);
|
|
case TIOCSIG: /* Send signal to other side of pty */
|
|
return pty_signal(tty, (int) arg);
|
|
case TIOCGPTN: /* TTY returns ENOTTY, but glibc expects EINVAL here */
|
|
return -EINVAL;
|
|
}
|
|
return -ENOIOCTLCMD;
|
|
}
|
|
|
|
static int legacy_count = CONFIG_LEGACY_PTY_COUNT;
|
|
/*
|
|
* not really modular, but the easiest way to keep compat with existing
|
|
* bootargs behaviour is to continue using module_param here.
|
|
*/
|
|
module_param(legacy_count, int, 0);
|
|
|
|
/*
|
|
* The master side of a pty can do TIOCSPTLCK and thus
|
|
* has pty_bsd_ioctl.
|
|
*/
|
|
static const struct tty_operations master_pty_ops_bsd = {
|
|
.install = pty_install,
|
|
.open = pty_open,
|
|
.close = pty_close,
|
|
.write = pty_write,
|
|
.write_room = pty_write_room,
|
|
.flush_buffer = pty_flush_buffer,
|
|
.chars_in_buffer = pty_chars_in_buffer,
|
|
.unthrottle = pty_unthrottle,
|
|
.ioctl = pty_bsd_ioctl,
|
|
.cleanup = pty_cleanup,
|
|
.resize = pty_resize,
|
|
.remove = pty_remove
|
|
};
|
|
|
|
static const struct tty_operations slave_pty_ops_bsd = {
|
|
.install = pty_install,
|
|
.open = pty_open,
|
|
.close = pty_close,
|
|
.write = pty_write,
|
|
.write_room = pty_write_room,
|
|
.flush_buffer = pty_flush_buffer,
|
|
.chars_in_buffer = pty_chars_in_buffer,
|
|
.unthrottle = pty_unthrottle,
|
|
.set_termios = pty_set_termios,
|
|
.cleanup = pty_cleanup,
|
|
.resize = pty_resize,
|
|
.start = pty_start,
|
|
.stop = pty_stop,
|
|
.remove = pty_remove
|
|
};
|
|
|
|
static void __init legacy_pty_init(void)
|
|
{
|
|
struct tty_driver *pty_driver, *pty_slave_driver;
|
|
|
|
if (legacy_count <= 0)
|
|
return;
|
|
|
|
pty_driver = tty_alloc_driver(legacy_count,
|
|
TTY_DRIVER_RESET_TERMIOS |
|
|
TTY_DRIVER_REAL_RAW |
|
|
TTY_DRIVER_DYNAMIC_ALLOC);
|
|
if (IS_ERR(pty_driver))
|
|
panic("Couldn't allocate pty driver");
|
|
|
|
pty_slave_driver = tty_alloc_driver(legacy_count,
|
|
TTY_DRIVER_RESET_TERMIOS |
|
|
TTY_DRIVER_REAL_RAW |
|
|
TTY_DRIVER_DYNAMIC_ALLOC);
|
|
if (IS_ERR(pty_slave_driver))
|
|
panic("Couldn't allocate pty slave driver");
|
|
|
|
pty_driver->driver_name = "pty_master";
|
|
pty_driver->name = "pty";
|
|
pty_driver->major = PTY_MASTER_MAJOR;
|
|
pty_driver->minor_start = 0;
|
|
pty_driver->type = TTY_DRIVER_TYPE_PTY;
|
|
pty_driver->subtype = PTY_TYPE_MASTER;
|
|
pty_driver->init_termios = tty_std_termios;
|
|
pty_driver->init_termios.c_iflag = 0;
|
|
pty_driver->init_termios.c_oflag = 0;
|
|
pty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
|
|
pty_driver->init_termios.c_lflag = 0;
|
|
pty_driver->init_termios.c_ispeed = 38400;
|
|
pty_driver->init_termios.c_ospeed = 38400;
|
|
pty_driver->other = pty_slave_driver;
|
|
tty_set_operations(pty_driver, &master_pty_ops_bsd);
|
|
|
|
pty_slave_driver->driver_name = "pty_slave";
|
|
pty_slave_driver->name = "ttyp";
|
|
pty_slave_driver->major = PTY_SLAVE_MAJOR;
|
|
pty_slave_driver->minor_start = 0;
|
|
pty_slave_driver->type = TTY_DRIVER_TYPE_PTY;
|
|
pty_slave_driver->subtype = PTY_TYPE_SLAVE;
|
|
pty_slave_driver->init_termios = tty_std_termios;
|
|
pty_slave_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
|
|
pty_slave_driver->init_termios.c_ispeed = 38400;
|
|
pty_slave_driver->init_termios.c_ospeed = 38400;
|
|
pty_slave_driver->other = pty_driver;
|
|
tty_set_operations(pty_slave_driver, &slave_pty_ops_bsd);
|
|
|
|
if (tty_register_driver(pty_driver))
|
|
panic("Couldn't register pty driver");
|
|
if (tty_register_driver(pty_slave_driver))
|
|
panic("Couldn't register pty slave driver");
|
|
}
|
|
#else
|
|
static inline void legacy_pty_init(void) { }
|
|
#endif
|
|
|
|
/* Unix98 devices */
|
|
#ifdef CONFIG_UNIX98_PTYS
|
|
|
|
static struct cdev ptmx_cdev;
|
|
|
|
static int pty_unix98_ioctl(struct tty_struct *tty,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
switch (cmd) {
|
|
case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
|
|
return pty_set_lock(tty, (int __user *)arg);
|
|
case TIOCGPTLCK: /* Get PT Lock status */
|
|
return pty_get_lock(tty, (int __user *)arg);
|
|
case TIOCPKT: /* Set PT packet mode */
|
|
return pty_set_pktmode(tty, (int __user *)arg);
|
|
case TIOCGPKT: /* Get PT packet mode */
|
|
return pty_get_pktmode(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;
|
|
}
|
|
|
|
/**
|
|
* ptm_unix98_lookup - find a pty master
|
|
* @driver: ptm driver
|
|
* @idx: tty index
|
|
*
|
|
* Look up a pty master device. Called under the tty_mutex for now.
|
|
* This provides our locking.
|
|
*/
|
|
|
|
static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver,
|
|
struct file *file, int idx)
|
|
{
|
|
/* Master must be open via /dev/ptmx */
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
|
|
/**
|
|
* pts_unix98_lookup - find a pty slave
|
|
* @driver: pts driver
|
|
* @idx: tty index
|
|
*
|
|
* Look up a pty master device. Called under the tty_mutex for now.
|
|
* This provides our locking for the tty pointer.
|
|
*/
|
|
|
|
static struct tty_struct *pts_unix98_lookup(struct tty_driver *driver,
|
|
struct file *file, int idx)
|
|
{
|
|
struct tty_struct *tty;
|
|
|
|
mutex_lock(&devpts_mutex);
|
|
tty = devpts_get_priv(file->f_path.dentry);
|
|
mutex_unlock(&devpts_mutex);
|
|
/* Master must be open before slave */
|
|
if (!tty)
|
|
return ERR_PTR(-EIO);
|
|
return tty;
|
|
}
|
|
|
|
static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
|
|
{
|
|
return pty_common_install(driver, tty, false);
|
|
}
|
|
|
|
/* this is called once with whichever end is closed last */
|
|
static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
|
|
{
|
|
struct pts_fs_info *fsi;
|
|
|
|
if (tty->driver->subtype == PTY_TYPE_MASTER)
|
|
fsi = tty->driver_data;
|
|
else
|
|
fsi = tty->link->driver_data;
|
|
devpts_kill_index(fsi, tty->index);
|
|
devpts_put_ref(fsi);
|
|
}
|
|
|
|
static const struct tty_operations ptm_unix98_ops = {
|
|
.lookup = ptm_unix98_lookup,
|
|
.install = pty_unix98_install,
|
|
.remove = pty_unix98_remove,
|
|
.open = pty_open,
|
|
.close = pty_close,
|
|
.write = pty_write,
|
|
.write_room = pty_write_room,
|
|
.flush_buffer = pty_flush_buffer,
|
|
.chars_in_buffer = pty_chars_in_buffer,
|
|
.unthrottle = pty_unthrottle,
|
|
.ioctl = pty_unix98_ioctl,
|
|
.resize = pty_resize,
|
|
.cleanup = pty_cleanup
|
|
};
|
|
|
|
static const struct tty_operations pty_unix98_ops = {
|
|
.lookup = pts_unix98_lookup,
|
|
.install = pty_unix98_install,
|
|
.remove = pty_unix98_remove,
|
|
.open = pty_open,
|
|
.close = pty_close,
|
|
.write = pty_write,
|
|
.write_room = pty_write_room,
|
|
.flush_buffer = pty_flush_buffer,
|
|
.chars_in_buffer = pty_chars_in_buffer,
|
|
.unthrottle = pty_unthrottle,
|
|
.set_termios = pty_set_termios,
|
|
.start = pty_start,
|
|
.stop = pty_stop,
|
|
.cleanup = pty_cleanup,
|
|
};
|
|
|
|
/**
|
|
* ptmx_open - open a unix 98 pty master
|
|
* @inode: inode of device file
|
|
* @filp: file pointer to tty
|
|
*
|
|
* Allocate a unix98 pty master device from the ptmx driver.
|
|
*
|
|
* Locking: tty_mutex protects the init_dev work. tty->count should
|
|
* protect the rest.
|
|
* allocated_ptys_lock handles the list of free pty numbers
|
|
*/
|
|
|
|
static int ptmx_open(struct inode *inode, struct file *filp)
|
|
{
|
|
struct pts_fs_info *fsi;
|
|
struct tty_struct *tty;
|
|
struct dentry *dentry;
|
|
int retval;
|
|
int index;
|
|
|
|
nonseekable_open(inode, filp);
|
|
|
|
/* We refuse fsnotify events on ptmx, since it's a shared resource */
|
|
filp->f_mode |= FMODE_NONOTIFY;
|
|
|
|
retval = tty_alloc_file(filp);
|
|
if (retval)
|
|
return retval;
|
|
|
|
fsi = devpts_get_ref(inode, filp);
|
|
retval = -ENODEV;
|
|
if (!fsi)
|
|
goto out_free_file;
|
|
|
|
/* find a device that is not in use. */
|
|
mutex_lock(&devpts_mutex);
|
|
index = devpts_new_index(fsi);
|
|
mutex_unlock(&devpts_mutex);
|
|
|
|
retval = index;
|
|
if (index < 0)
|
|
goto out_put_ref;
|
|
|
|
|
|
mutex_lock(&tty_mutex);
|
|
tty = tty_init_dev(ptm_driver, index);
|
|
/* The tty returned here is locked so we can safely
|
|
drop the mutex */
|
|
mutex_unlock(&tty_mutex);
|
|
|
|
retval = PTR_ERR(tty);
|
|
if (IS_ERR(tty))
|
|
goto out;
|
|
|
|
/*
|
|
* From here on out, the tty is "live", and the index and
|
|
* fsi will be killed/put by the tty_release()
|
|
*/
|
|
set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
|
|
tty->driver_data = fsi;
|
|
|
|
tty_add_file(tty, filp);
|
|
|
|
dentry = devpts_pty_new(fsi, index, tty->link);
|
|
if (IS_ERR(dentry)) {
|
|
retval = PTR_ERR(dentry);
|
|
goto err_release;
|
|
}
|
|
tty->link->driver_data = dentry;
|
|
|
|
retval = ptm_driver->ops->open(tty, filp);
|
|
if (retval)
|
|
goto err_release;
|
|
|
|
tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
|
|
|
|
tty_unlock(tty);
|
|
return 0;
|
|
err_release:
|
|
tty_unlock(tty);
|
|
// This will also put-ref the fsi
|
|
tty_release(inode, filp);
|
|
return retval;
|
|
out:
|
|
devpts_kill_index(fsi, index);
|
|
out_put_ref:
|
|
devpts_put_ref(fsi);
|
|
out_free_file:
|
|
tty_free_file(filp);
|
|
return retval;
|
|
}
|
|
|
|
static struct file_operations ptmx_fops;
|
|
|
|
static void __init unix98_pty_init(void)
|
|
{
|
|
ptm_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
|
|
TTY_DRIVER_RESET_TERMIOS |
|
|
TTY_DRIVER_REAL_RAW |
|
|
TTY_DRIVER_DYNAMIC_DEV |
|
|
TTY_DRIVER_DEVPTS_MEM |
|
|
TTY_DRIVER_DYNAMIC_ALLOC);
|
|
if (IS_ERR(ptm_driver))
|
|
panic("Couldn't allocate Unix98 ptm driver");
|
|
pts_driver = tty_alloc_driver(NR_UNIX98_PTY_MAX,
|
|
TTY_DRIVER_RESET_TERMIOS |
|
|
TTY_DRIVER_REAL_RAW |
|
|
TTY_DRIVER_DYNAMIC_DEV |
|
|
TTY_DRIVER_DEVPTS_MEM |
|
|
TTY_DRIVER_DYNAMIC_ALLOC);
|
|
if (IS_ERR(pts_driver))
|
|
panic("Couldn't allocate Unix98 pts driver");
|
|
|
|
ptm_driver->driver_name = "pty_master";
|
|
ptm_driver->name = "ptm";
|
|
ptm_driver->major = UNIX98_PTY_MASTER_MAJOR;
|
|
ptm_driver->minor_start = 0;
|
|
ptm_driver->type = TTY_DRIVER_TYPE_PTY;
|
|
ptm_driver->subtype = PTY_TYPE_MASTER;
|
|
ptm_driver->init_termios = tty_std_termios;
|
|
ptm_driver->init_termios.c_iflag = 0;
|
|
ptm_driver->init_termios.c_oflag = 0;
|
|
ptm_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
|
|
ptm_driver->init_termios.c_lflag = 0;
|
|
ptm_driver->init_termios.c_ispeed = 38400;
|
|
ptm_driver->init_termios.c_ospeed = 38400;
|
|
ptm_driver->other = pts_driver;
|
|
tty_set_operations(ptm_driver, &ptm_unix98_ops);
|
|
|
|
pts_driver->driver_name = "pty_slave";
|
|
pts_driver->name = "pts";
|
|
pts_driver->major = UNIX98_PTY_SLAVE_MAJOR;
|
|
pts_driver->minor_start = 0;
|
|
pts_driver->type = TTY_DRIVER_TYPE_PTY;
|
|
pts_driver->subtype = PTY_TYPE_SLAVE;
|
|
pts_driver->init_termios = tty_std_termios;
|
|
pts_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
|
|
pts_driver->init_termios.c_ispeed = 38400;
|
|
pts_driver->init_termios.c_ospeed = 38400;
|
|
pts_driver->other = ptm_driver;
|
|
tty_set_operations(pts_driver, &pty_unix98_ops);
|
|
|
|
if (tty_register_driver(ptm_driver))
|
|
panic("Couldn't register Unix98 ptm driver");
|
|
if (tty_register_driver(pts_driver))
|
|
panic("Couldn't register Unix98 pts driver");
|
|
|
|
/* Now create the /dev/ptmx special device */
|
|
tty_default_fops(&ptmx_fops);
|
|
ptmx_fops.open = ptmx_open;
|
|
|
|
cdev_init(&ptmx_cdev, &ptmx_fops);
|
|
if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) ||
|
|
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0)
|
|
panic("Couldn't register /dev/ptmx driver");
|
|
device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx");
|
|
}
|
|
|
|
#else
|
|
static inline void unix98_pty_init(void) { }
|
|
#endif
|
|
|
|
static int __init pty_init(void)
|
|
{
|
|
legacy_pty_init();
|
|
unix98_pty_init();
|
|
return 0;
|
|
}
|
|
device_initcall(pty_init);
|