2 * linux/drivers/char/tty_io.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
69 #include <linux/types.h>
70 #include <linux/major.h>
71 #include <linux/errno.h>
72 #include <linux/signal.h>
73 #include <linux/fcntl.h>
74 #include <linux/sched.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/smp_lock.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
100 #include <linux/uaccess.h>
101 #include <asm/system.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
112 #define TTY_PARANOIA_CHECK 1
113 #define CHECK_TTY_COUNT 1
115 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
116 .c_iflag = ICRNL | IXON,
117 .c_oflag = OPOST | ONLCR,
118 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
119 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
120 ECHOCTL | ECHOKE | IEXTEN,
126 EXPORT_SYMBOL(tty_std_termios);
128 /* This list gets poked at by procfs and various bits of boot up code. This
129 could do with some rationalisation such as pulling the tty proc function
132 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
134 /* Mutex to protect creating and releasing a tty. This is shared with
135 vt.c for deeply disgusting hack reasons */
136 DEFINE_MUTEX(tty_mutex);
137 EXPORT_SYMBOL(tty_mutex);
139 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
140 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
141 ssize_t redirected_tty_write(struct file *, const char __user *,
143 static unsigned int tty_poll(struct file *, poll_table *);
144 static int tty_open(struct inode *, struct file *);
145 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
147 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
150 #define tty_compat_ioctl NULL
152 static int __tty_fasync(int fd, struct file *filp, int on);
153 static int tty_fasync(int fd, struct file *filp, int on);
154 static void release_tty(struct tty_struct *tty, int idx);
155 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
156 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
159 * alloc_tty_struct - allocate a tty object
161 * Return a new empty tty structure. The data fields have not
162 * been initialized in any way but has been zeroed
167 struct tty_struct *alloc_tty_struct(void)
169 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
173 * free_tty_struct - free a disused tty
174 * @tty: tty struct to free
176 * Free the write buffers, tty queue and tty memory itself.
178 * Locking: none. Must be called after tty is definitely unused
181 void free_tty_struct(struct tty_struct *tty)
183 kfree(tty->write_buf);
184 tty_buffer_free_all(tty);
188 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
191 * tty_name - return tty naming
192 * @tty: tty structure
193 * @buf: buffer for output
195 * Convert a tty structure into a name. The name reflects the kernel
196 * naming policy and if udev is in use may not reflect user space
201 char *tty_name(struct tty_struct *tty, char *buf)
203 if (!tty) /* Hmm. NULL pointer. That's fun. */
204 strcpy(buf, "NULL tty");
206 strcpy(buf, tty->name);
210 EXPORT_SYMBOL(tty_name);
212 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
215 #ifdef TTY_PARANOIA_CHECK
218 "null TTY for (%d:%d) in %s\n",
219 imajor(inode), iminor(inode), routine);
222 if (tty->magic != TTY_MAGIC) {
224 "bad magic number for tty struct (%d:%d) in %s\n",
225 imajor(inode), iminor(inode), routine);
232 static int check_tty_count(struct tty_struct *tty, const char *routine)
234 #ifdef CHECK_TTY_COUNT
239 list_for_each(p, &tty->tty_files) {
243 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
244 tty->driver->subtype == PTY_TYPE_SLAVE &&
245 tty->link && tty->link->count)
247 if (tty->count != count) {
248 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
249 "!= #fd's(%d) in %s\n",
250 tty->name, tty->count, count, routine);
258 * get_tty_driver - find device of a tty
259 * @dev_t: device identifier
260 * @index: returns the index of the tty
262 * This routine returns a tty driver structure, given a device number
263 * and also passes back the index number.
265 * Locking: caller must hold tty_mutex
268 static struct tty_driver *get_tty_driver(dev_t device, int *index)
270 struct tty_driver *p;
272 list_for_each_entry(p, &tty_drivers, tty_drivers) {
273 dev_t base = MKDEV(p->major, p->minor_start);
274 if (device < base || device >= base + p->num)
276 *index = device - base;
277 return tty_driver_kref_get(p);
282 #ifdef CONFIG_CONSOLE_POLL
285 * tty_find_polling_driver - find device of a polled tty
286 * @name: name string to match
287 * @line: pointer to resulting tty line nr
289 * This routine returns a tty driver structure, given a name
290 * and the condition that the tty driver is capable of polled
293 struct tty_driver *tty_find_polling_driver(char *name, int *line)
295 struct tty_driver *p, *res = NULL;
300 for (str = name; *str; str++)
301 if ((*str >= '0' && *str <= '9') || *str == ',')
307 tty_line = simple_strtoul(str, &str, 10);
309 mutex_lock(&tty_mutex);
310 /* Search through the tty devices to look for a match */
311 list_for_each_entry(p, &tty_drivers, tty_drivers) {
312 if (strncmp(name, p->name, len) != 0)
320 if (tty_line >= 0 && tty_line <= p->num && p->ops &&
321 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
322 res = tty_driver_kref_get(p);
327 mutex_unlock(&tty_mutex);
331 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
335 * tty_check_change - check for POSIX terminal changes
338 * If we try to write to, or set the state of, a terminal and we're
339 * not in the foreground, send a SIGTTOU. If the signal is blocked or
340 * ignored, go ahead and perform the operation. (POSIX 7.2)
345 int tty_check_change(struct tty_struct *tty)
350 if (current->signal->tty != tty)
353 spin_lock_irqsave(&tty->ctrl_lock, flags);
356 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
359 if (task_pgrp(current) == tty->pgrp)
361 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
362 if (is_ignored(SIGTTOU))
364 if (is_current_pgrp_orphaned()) {
368 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
369 set_thread_flag(TIF_SIGPENDING);
374 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
378 EXPORT_SYMBOL(tty_check_change);
380 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
381 size_t count, loff_t *ppos)
386 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
387 size_t count, loff_t *ppos)
392 /* No kernel lock held - none needed ;) */
393 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
395 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
398 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
401 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
404 static long hung_up_tty_compat_ioctl(struct file *file,
405 unsigned int cmd, unsigned long arg)
407 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
410 static const struct file_operations tty_fops = {
415 .unlocked_ioctl = tty_ioctl,
416 .compat_ioctl = tty_compat_ioctl,
418 .release = tty_release,
419 .fasync = tty_fasync,
422 static const struct file_operations console_fops = {
425 .write = redirected_tty_write,
427 .unlocked_ioctl = tty_ioctl,
428 .compat_ioctl = tty_compat_ioctl,
430 .release = tty_release,
431 .fasync = tty_fasync,
434 static const struct file_operations hung_up_tty_fops = {
436 .read = hung_up_tty_read,
437 .write = hung_up_tty_write,
438 .poll = hung_up_tty_poll,
439 .unlocked_ioctl = hung_up_tty_ioctl,
440 .compat_ioctl = hung_up_tty_compat_ioctl,
441 .release = tty_release,
444 static DEFINE_SPINLOCK(redirect_lock);
445 static struct file *redirect;
448 * tty_wakeup - request more data
451 * Internal and external helper for wakeups of tty. This function
452 * informs the line discipline if present that the driver is ready
453 * to receive more output data.
456 void tty_wakeup(struct tty_struct *tty)
458 struct tty_ldisc *ld;
460 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
461 ld = tty_ldisc_ref(tty);
463 if (ld->ops->write_wakeup)
464 ld->ops->write_wakeup(tty);
468 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
471 EXPORT_SYMBOL_GPL(tty_wakeup);
474 * do_tty_hangup - actual handler for hangup events
477 * This can be called by the "eventd" kernel thread. That is process
478 * synchronous but doesn't hold any locks, so we need to make sure we
479 * have the appropriate locks for what we're doing.
481 * The hangup event clears any pending redirections onto the hung up
482 * device. It ensures future writes will error and it does the needed
483 * line discipline hangup and signal delivery. The tty object itself
488 * redirect lock for undoing redirection
489 * file list lock for manipulating list of ttys
490 * tty_ldisc_lock from called functions
491 * termios_mutex resetting termios data
492 * tasklist_lock to walk task list for hangup event
493 * ->siglock to protect ->signal/->sighand
495 static void do_tty_hangup(struct work_struct *work)
497 struct tty_struct *tty =
498 container_of(work, struct tty_struct, hangup_work);
499 struct file *cons_filp = NULL;
500 struct file *filp, *f = NULL;
501 struct task_struct *p;
502 int closecount = 0, n;
510 spin_lock(&redirect_lock);
511 if (redirect && redirect->private_data == tty) {
515 spin_unlock(&redirect_lock);
517 /* inuse_filps is protected by the single tty lock,
518 this really needs to change if we want to flush the
519 workqueue with the lock held */
520 tty_lock_nested(); /* called with BTM held from pty_close and
522 check_tty_count(tty, "do_tty_hangup");
525 /* This breaks for file handles being sent over AF_UNIX sockets ? */
526 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
527 if (filp->f_op->write == redirected_tty_write)
529 if (filp->f_op->write != tty_write)
532 __tty_fasync(-1, filp, 0); /* can't block */
533 filp->f_op = &hung_up_tty_fops;
537 tty_ldisc_hangup(tty);
539 read_lock(&tasklist_lock);
541 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
542 spin_lock_irq(&p->sighand->siglock);
543 if (p->signal->tty == tty) {
544 p->signal->tty = NULL;
545 /* We defer the dereferences outside fo
549 if (!p->signal->leader) {
550 spin_unlock_irq(&p->sighand->siglock);
553 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
554 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
555 put_pid(p->signal->tty_old_pgrp); /* A noop */
556 spin_lock_irqsave(&tty->ctrl_lock, flags);
558 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
559 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
560 spin_unlock_irq(&p->sighand->siglock);
561 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
563 read_unlock(&tasklist_lock);
565 spin_lock_irqsave(&tty->ctrl_lock, flags);
566 clear_bit(TTY_THROTTLED, &tty->flags);
567 clear_bit(TTY_PUSH, &tty->flags);
568 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
569 put_pid(tty->session);
573 tty->ctrl_status = 0;
574 set_bit(TTY_HUPPED, &tty->flags);
575 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
577 /* Account for the p->signal references we killed */
582 * If one of the devices matches a console pointer, we
583 * cannot just call hangup() because that will cause
584 * tty->count and state->count to go out of sync.
585 * So we just call close() the right number of times.
589 for (n = 0; n < closecount; n++)
590 tty->ops->close(tty, cons_filp);
591 } else if (tty->ops->hangup)
592 (tty->ops->hangup)(tty);
594 * We don't want to have driver/ldisc interactions beyond
595 * the ones we did here. The driver layer expects no
596 * calls after ->hangup() from the ldisc side. However we
597 * can't yet guarantee all that.
599 set_bit(TTY_HUPPED, &tty->flags);
600 tty_ldisc_enable(tty);
607 * tty_hangup - trigger a hangup event
608 * @tty: tty to hangup
610 * A carrier loss (virtual or otherwise) has occurred on this like
611 * schedule a hangup sequence to run after this event.
614 void tty_hangup(struct tty_struct *tty)
616 #ifdef TTY_DEBUG_HANGUP
618 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
620 schedule_work(&tty->hangup_work);
623 EXPORT_SYMBOL(tty_hangup);
626 * tty_vhangup - process vhangup
627 * @tty: tty to hangup
629 * The user has asked via system call for the terminal to be hung up.
630 * We do this synchronously so that when the syscall returns the process
631 * is complete. That guarantee is necessary for security reasons.
634 void tty_vhangup(struct tty_struct *tty)
636 #ifdef TTY_DEBUG_HANGUP
639 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
641 do_tty_hangup(&tty->hangup_work);
644 EXPORT_SYMBOL(tty_vhangup);
647 * tty_vhangup_self - process vhangup for own ctty
649 * Perform a vhangup on the current controlling tty
652 void tty_vhangup_self(void)
654 struct tty_struct *tty;
656 tty = get_current_tty();
664 * tty_hung_up_p - was tty hung up
665 * @filp: file pointer of tty
667 * Return true if the tty has been subject to a vhangup or a carrier
671 int tty_hung_up_p(struct file *filp)
673 return (filp->f_op == &hung_up_tty_fops);
676 EXPORT_SYMBOL(tty_hung_up_p);
678 static void session_clear_tty(struct pid *session)
680 struct task_struct *p;
681 do_each_pid_task(session, PIDTYPE_SID, p) {
683 } while_each_pid_task(session, PIDTYPE_SID, p);
687 * disassociate_ctty - disconnect controlling tty
688 * @on_exit: true if exiting so need to "hang up" the session
690 * This function is typically called only by the session leader, when
691 * it wants to disassociate itself from its controlling tty.
693 * It performs the following functions:
694 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
695 * (2) Clears the tty from being controlling the session
696 * (3) Clears the controlling tty for all processes in the
699 * The argument on_exit is set to 1 if called when a process is
700 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
703 * BTM is taken for hysterical raisins, and held when
704 * called from no_tty().
705 * tty_mutex is taken to protect tty
706 * ->siglock is taken to protect ->signal/->sighand
707 * tasklist_lock is taken to walk process list for sessions
708 * ->siglock is taken to protect ->signal/->sighand
711 void disassociate_ctty(int on_exit)
713 struct tty_struct *tty;
714 struct pid *tty_pgrp = NULL;
716 if (!current->signal->leader)
719 tty = get_current_tty();
721 tty_pgrp = get_pid(tty->pgrp);
722 tty_lock_nested(); /* see above */
723 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
727 } else if (on_exit) {
728 struct pid *old_pgrp;
729 spin_lock_irq(¤t->sighand->siglock);
730 old_pgrp = current->signal->tty_old_pgrp;
731 current->signal->tty_old_pgrp = NULL;
732 spin_unlock_irq(¤t->sighand->siglock);
734 kill_pgrp(old_pgrp, SIGHUP, on_exit);
735 kill_pgrp(old_pgrp, SIGCONT, on_exit);
741 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
743 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
747 spin_lock_irq(¤t->sighand->siglock);
748 put_pid(current->signal->tty_old_pgrp);
749 current->signal->tty_old_pgrp = NULL;
750 spin_unlock_irq(¤t->sighand->siglock);
752 tty = get_current_tty();
755 spin_lock_irqsave(&tty->ctrl_lock, flags);
756 put_pid(tty->session);
760 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
763 #ifdef TTY_DEBUG_HANGUP
764 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
769 /* Now clear signal->tty under the lock */
770 read_lock(&tasklist_lock);
771 session_clear_tty(task_session(current));
772 read_unlock(&tasklist_lock);
777 * no_tty - Ensure the current process does not have a controlling tty
781 struct task_struct *tsk = current;
783 disassociate_ctty(0);
790 * stop_tty - propagate flow control
793 * Perform flow control to the driver. For PTY/TTY pairs we
794 * must also propagate the TIOCKPKT status. May be called
795 * on an already stopped device and will not re-call the driver
798 * This functionality is used by both the line disciplines for
799 * halting incoming flow and by the driver. It may therefore be
800 * called from any context, may be under the tty atomic_write_lock
804 * Uses the tty control lock internally
807 void stop_tty(struct tty_struct *tty)
810 spin_lock_irqsave(&tty->ctrl_lock, flags);
812 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
816 if (tty->link && tty->link->packet) {
817 tty->ctrl_status &= ~TIOCPKT_START;
818 tty->ctrl_status |= TIOCPKT_STOP;
819 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
821 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
823 (tty->ops->stop)(tty);
826 EXPORT_SYMBOL(stop_tty);
829 * start_tty - propagate flow control
832 * Start a tty that has been stopped if at all possible. Perform
833 * any necessary wakeups and propagate the TIOCPKT status. If this
834 * is the tty was previous stopped and is being started then the
835 * driver start method is invoked and the line discipline woken.
841 void start_tty(struct tty_struct *tty)
844 spin_lock_irqsave(&tty->ctrl_lock, flags);
845 if (!tty->stopped || tty->flow_stopped) {
846 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
850 if (tty->link && tty->link->packet) {
851 tty->ctrl_status &= ~TIOCPKT_STOP;
852 tty->ctrl_status |= TIOCPKT_START;
853 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
855 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
857 (tty->ops->start)(tty);
858 /* If we have a running line discipline it may need kicking */
862 EXPORT_SYMBOL(start_tty);
865 * tty_read - read method for tty device files
866 * @file: pointer to tty file
868 * @count: size of user buffer
871 * Perform the read system call function on this terminal device. Checks
872 * for hung up devices before calling the line discipline method.
875 * Locks the line discipline internally while needed. Multiple
876 * read calls may be outstanding in parallel.
879 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
883 struct tty_struct *tty;
885 struct tty_ldisc *ld;
887 tty = (struct tty_struct *)file->private_data;
888 inode = file->f_path.dentry->d_inode;
889 if (tty_paranoia_check(tty, inode, "tty_read"))
891 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
894 /* We want to wait for the line discipline to sort out in this
896 ld = tty_ldisc_ref_wait(tty);
898 i = (ld->ops->read)(tty, file, buf, count);
903 inode->i_atime = current_fs_time(inode->i_sb);
907 void tty_write_unlock(struct tty_struct *tty)
909 mutex_unlock(&tty->atomic_write_lock);
910 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
913 int tty_write_lock(struct tty_struct *tty, int ndelay)
915 if (!mutex_trylock(&tty->atomic_write_lock)) {
918 if (mutex_lock_interruptible(&tty->atomic_write_lock))
925 * Split writes up in sane blocksizes to avoid
926 * denial-of-service type attacks
928 static inline ssize_t do_tty_write(
929 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
930 struct tty_struct *tty,
932 const char __user *buf,
935 ssize_t ret, written = 0;
938 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
943 * We chunk up writes into a temporary buffer. This
944 * simplifies low-level drivers immensely, since they
945 * don't have locking issues and user mode accesses.
947 * But if TTY_NO_WRITE_SPLIT is set, we should use a
950 * The default chunk-size is 2kB, because the NTTY
951 * layer has problems with bigger chunks. It will
952 * claim to be able to handle more characters than
955 * FIXME: This can probably go away now except that 64K chunks
956 * are too likely to fail unless switched to vmalloc...
959 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
964 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
965 if (tty->write_cnt < chunk) {
966 unsigned char *buf_chunk;
971 buf_chunk = kmalloc(chunk, GFP_KERNEL);
976 kfree(tty->write_buf);
977 tty->write_cnt = chunk;
978 tty->write_buf = buf_chunk;
981 /* Do the write .. */
987 if (copy_from_user(tty->write_buf, buf, size))
989 ret = write(tty, file, tty->write_buf, size);
998 if (signal_pending(current))
1003 struct inode *inode = file->f_path.dentry->d_inode;
1004 inode->i_mtime = current_fs_time(inode->i_sb);
1008 tty_write_unlock(tty);
1013 * tty_write_message - write a message to a certain tty, not just the console.
1014 * @tty: the destination tty_struct
1015 * @msg: the message to write
1017 * This is used for messages that need to be redirected to a specific tty.
1018 * We don't put it into the syslog queue right now maybe in the future if
1021 * We must still hold the BTM and test the CLOSING flag for the moment.
1024 void tty_write_message(struct tty_struct *tty, char *msg)
1027 mutex_lock(&tty->atomic_write_lock);
1029 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1031 tty->ops->write(tty, msg, strlen(msg));
1034 tty_write_unlock(tty);
1041 * tty_write - write method for tty device file
1042 * @file: tty file pointer
1043 * @buf: user data to write
1044 * @count: bytes to write
1047 * Write data to a tty device via the line discipline.
1050 * Locks the line discipline as required
1051 * Writes to the tty driver are serialized by the atomic_write_lock
1052 * and are then processed in chunks to the device. The line discipline
1053 * write method will not be invoked in parallel for each device.
1056 static ssize_t tty_write(struct file *file, const char __user *buf,
1057 size_t count, loff_t *ppos)
1059 struct tty_struct *tty;
1060 struct inode *inode = file->f_path.dentry->d_inode;
1062 struct tty_ldisc *ld;
1064 tty = (struct tty_struct *)file->private_data;
1065 if (tty_paranoia_check(tty, inode, "tty_write"))
1067 if (!tty || !tty->ops->write ||
1068 (test_bit(TTY_IO_ERROR, &tty->flags)))
1070 /* Short term debug to catch buggy drivers */
1071 if (tty->ops->write_room == NULL)
1072 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1074 ld = tty_ldisc_ref_wait(tty);
1075 if (!ld->ops->write)
1078 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1079 tty_ldisc_deref(ld);
1083 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1084 size_t count, loff_t *ppos)
1086 struct file *p = NULL;
1088 spin_lock(&redirect_lock);
1093 spin_unlock(&redirect_lock);
1097 res = vfs_write(p, buf, count, &p->f_pos);
1101 return tty_write(file, buf, count, ppos);
1104 static char ptychar[] = "pqrstuvwxyzabcde";
1107 * pty_line_name - generate name for a pty
1108 * @driver: the tty driver in use
1109 * @index: the minor number
1110 * @p: output buffer of at least 6 bytes
1112 * Generate a name from a driver reference and write it to the output
1117 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1119 int i = index + driver->name_base;
1120 /* ->name is initialized to "ttyp", but "tty" is expected */
1121 sprintf(p, "%s%c%x",
1122 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1123 ptychar[i >> 4 & 0xf], i & 0xf);
1127 * tty_line_name - generate name for a tty
1128 * @driver: the tty driver in use
1129 * @index: the minor number
1130 * @p: output buffer of at least 7 bytes
1132 * Generate a name from a driver reference and write it to the output
1137 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1139 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1143 * tty_driver_lookup_tty() - find an existing tty, if any
1144 * @driver: the driver for the tty
1145 * @idx: the minor number
1147 * Return the tty, if found or ERR_PTR() otherwise.
1149 * Locking: tty_mutex must be held. If tty is found, the mutex must
1150 * be held until the 'fast-open' is also done. Will change once we
1151 * have refcounting in the driver and per driver locking
1153 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1154 struct inode *inode, int idx)
1156 struct tty_struct *tty;
1158 if (driver->ops->lookup)
1159 return driver->ops->lookup(driver, inode, idx);
1161 tty = driver->ttys[idx];
1166 * tty_init_termios - helper for termios setup
1167 * @tty: the tty to set up
1169 * Initialise the termios structures for this tty. Thus runs under
1170 * the tty_mutex currently so we can be relaxed about ordering.
1173 int tty_init_termios(struct tty_struct *tty)
1175 struct ktermios *tp;
1176 int idx = tty->index;
1178 tp = tty->driver->termios[idx];
1180 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1183 memcpy(tp, &tty->driver->init_termios,
1184 sizeof(struct ktermios));
1185 tty->driver->termios[idx] = tp;
1188 tty->termios_locked = tp + 1;
1190 /* Compatibility until drivers always set this */
1191 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1192 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1195 EXPORT_SYMBOL_GPL(tty_init_termios);
1198 * tty_driver_install_tty() - install a tty entry in the driver
1199 * @driver: the driver for the tty
1202 * Install a tty object into the driver tables. The tty->index field
1203 * will be set by the time this is called. This method is responsible
1204 * for ensuring any need additional structures are allocated and
1207 * Locking: tty_mutex for now
1209 static int tty_driver_install_tty(struct tty_driver *driver,
1210 struct tty_struct *tty)
1212 int idx = tty->index;
1215 if (driver->ops->install) {
1216 tty_lock_nested(); /* already called with BTM held */
1217 ret = driver->ops->install(driver, tty);
1222 if (tty_init_termios(tty) == 0) {
1224 tty_driver_kref_get(driver);
1226 driver->ttys[idx] = tty;
1234 * tty_driver_remove_tty() - remove a tty from the driver tables
1235 * @driver: the driver for the tty
1236 * @idx: the minor number
1238 * Remvoe a tty object from the driver tables. The tty->index field
1239 * will be set by the time this is called.
1241 * Locking: tty_mutex for now
1243 static void tty_driver_remove_tty(struct tty_driver *driver,
1244 struct tty_struct *tty)
1246 if (driver->ops->remove)
1247 driver->ops->remove(driver, tty);
1249 driver->ttys[tty->index] = NULL;
1253 * tty_reopen() - fast re-open of an open tty
1254 * @tty - the tty to open
1256 * Return 0 on success, -errno on error.
1258 * Locking: tty_mutex must be held from the time the tty was found
1259 * till this open completes.
1261 static int tty_reopen(struct tty_struct *tty)
1263 struct tty_driver *driver = tty->driver;
1265 if (test_bit(TTY_CLOSING, &tty->flags))
1268 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1269 driver->subtype == PTY_TYPE_MASTER) {
1271 * special case for PTY masters: only one open permitted,
1272 * and the slave side open count is incremented as well.
1280 tty->driver = driver; /* N.B. why do this every time?? */
1282 mutex_lock(&tty->ldisc_mutex);
1283 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1284 mutex_unlock(&tty->ldisc_mutex);
1290 * tty_init_dev - initialise a tty device
1291 * @driver: tty driver we are opening a device on
1292 * @idx: device index
1293 * @ret_tty: returned tty structure
1294 * @first_ok: ok to open a new device (used by ptmx)
1296 * Prepare a tty device. This may not be a "new" clean device but
1297 * could also be an active device. The pty drivers require special
1298 * handling because of this.
1301 * The function is called under the tty_mutex, which
1302 * protects us from the tty struct or driver itself going away.
1304 * On exit the tty device has the line discipline attached and
1305 * a reference count of 1. If a pair was created for pty/tty use
1306 * and the other was a pty master then it too has a reference count of 1.
1308 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1309 * failed open. The new code protects the open with a mutex, so it's
1310 * really quite straightforward. The mutex locking can probably be
1311 * relaxed for the (most common) case of reopening a tty.
1314 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1317 struct tty_struct *tty;
1320 tty_lock_nested(); /* always called with tty lock held already */
1322 /* Check if pty master is being opened multiple times */
1323 if (driver->subtype == PTY_TYPE_MASTER &&
1324 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1326 return ERR_PTR(-EIO);
1331 * First time open is complex, especially for PTY devices.
1332 * This code guarantees that either everything succeeds and the
1333 * TTY is ready for operation, or else the table slots are vacated
1334 * and the allocated memory released. (Except that the termios
1335 * and locked termios may be retained.)
1338 if (!try_module_get(driver->owner))
1339 return ERR_PTR(-ENODEV);
1341 tty = alloc_tty_struct();
1344 initialize_tty_struct(tty, driver, idx);
1346 retval = tty_driver_install_tty(driver, tty);
1348 free_tty_struct(tty);
1349 module_put(driver->owner);
1350 return ERR_PTR(retval);
1354 * Structures all installed ... call the ldisc open routines.
1355 * If we fail here just call release_tty to clean up. No need
1356 * to decrement the use counts, as release_tty doesn't care.
1358 retval = tty_ldisc_setup(tty, tty->link);
1360 goto release_mem_out;
1364 module_put(driver->owner);
1365 return ERR_PTR(-ENOMEM);
1367 /* call the tty release_tty routine to clean out this slot */
1369 if (printk_ratelimit())
1370 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1371 "clearing slot %d\n", idx);
1373 release_tty(tty, idx);
1375 return ERR_PTR(retval);
1378 void tty_free_termios(struct tty_struct *tty)
1380 struct ktermios *tp;
1381 int idx = tty->index;
1382 /* Kill this flag and push into drivers for locking etc */
1383 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1384 /* FIXME: Locking on ->termios array */
1386 tty->driver->termios[idx] = NULL;
1390 EXPORT_SYMBOL(tty_free_termios);
1392 void tty_shutdown(struct tty_struct *tty)
1394 tty_driver_remove_tty(tty->driver, tty);
1395 tty_free_termios(tty);
1397 EXPORT_SYMBOL(tty_shutdown);
1400 * release_one_tty - release tty structure memory
1401 * @kref: kref of tty we are obliterating
1403 * Releases memory associated with a tty structure, and clears out the
1404 * driver table slots. This function is called when a device is no longer
1405 * in use. It also gets called when setup of a device fails.
1408 * tty_mutex - sometimes only
1409 * takes the file list lock internally when working on the list
1410 * of ttys that the driver keeps.
1412 * This method gets called from a work queue so that the driver private
1413 * cleanup ops can sleep (needed for USB at least)
1415 static void release_one_tty(struct work_struct *work)
1417 struct tty_struct *tty =
1418 container_of(work, struct tty_struct, hangup_work);
1419 struct tty_driver *driver = tty->driver;
1421 if (tty->ops->cleanup)
1422 tty->ops->cleanup(tty);
1425 tty_driver_kref_put(driver);
1426 module_put(driver->owner);
1429 list_del_init(&tty->tty_files);
1433 put_pid(tty->session);
1434 free_tty_struct(tty);
1437 static void queue_release_one_tty(struct kref *kref)
1439 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1441 if (tty->ops->shutdown)
1442 tty->ops->shutdown(tty);
1446 /* The hangup queue is now free so we can reuse it rather than
1447 waste a chunk of memory for each port */
1448 INIT_WORK(&tty->hangup_work, release_one_tty);
1449 schedule_work(&tty->hangup_work);
1453 * tty_kref_put - release a tty kref
1456 * Release a reference to a tty device and if need be let the kref
1457 * layer destruct the object for us
1460 void tty_kref_put(struct tty_struct *tty)
1463 kref_put(&tty->kref, queue_release_one_tty);
1465 EXPORT_SYMBOL(tty_kref_put);
1468 * release_tty - release tty structure memory
1470 * Release both @tty and a possible linked partner (think pty pair),
1471 * and decrement the refcount of the backing module.
1474 * tty_mutex - sometimes only
1475 * takes the file list lock internally when working on the list
1476 * of ttys that the driver keeps.
1477 * FIXME: should we require tty_mutex is held here ??
1480 static void release_tty(struct tty_struct *tty, int idx)
1482 /* This should always be true but check for the moment */
1483 WARN_ON(tty->index != idx);
1486 tty_kref_put(tty->link);
1491 * tty_release - vfs callback for close
1492 * @inode: inode of tty
1493 * @filp: file pointer for handle to tty
1495 * Called the last time each file handle is closed that references
1496 * this tty. There may however be several such references.
1499 * Takes bkl. See tty_release_dev
1501 * Even releasing the tty structures is a tricky business.. We have
1502 * to be very careful that the structures are all released at the
1503 * same time, as interrupts might otherwise get the wrong pointers.
1505 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1506 * lead to double frees or releasing memory still in use.
1509 int tty_release(struct inode *inode, struct file *filp)
1511 struct tty_struct *tty, *o_tty;
1512 int pty_master, tty_closing, o_tty_closing, do_sleep;
1517 tty = (struct tty_struct *)filp->private_data;
1518 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1522 check_tty_count(tty, "tty_release_dev");
1524 __tty_fasync(-1, filp, 0);
1527 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1528 tty->driver->subtype == PTY_TYPE_MASTER);
1529 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1532 #ifdef TTY_PARANOIA_CHECK
1533 if (idx < 0 || idx >= tty->driver->num) {
1534 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1535 "free (%s)\n", tty->name);
1540 if (tty != tty->driver->ttys[idx]) {
1542 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1543 "for (%s)\n", idx, tty->name);
1546 if (tty->termios != tty->driver->termios[idx]) {
1548 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1556 #ifdef TTY_DEBUG_HANGUP
1557 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1558 tty_name(tty, buf), tty->count);
1561 #ifdef TTY_PARANOIA_CHECK
1562 if (tty->driver->other &&
1563 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1564 if (o_tty != tty->driver->other->ttys[idx]) {
1566 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1567 "not o_tty for (%s)\n",
1571 if (o_tty->termios != tty->driver->other->termios[idx]) {
1573 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1574 "not o_termios for (%s)\n",
1578 if (o_tty->link != tty) {
1580 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1585 if (tty->ops->close)
1586 tty->ops->close(tty, filp);
1590 * Sanity check: if tty->count is going to zero, there shouldn't be
1591 * any waiters on tty->read_wait or tty->write_wait. We test the
1592 * wait queues and kick everyone out _before_ actually starting to
1593 * close. This ensures that we won't block while releasing the tty
1596 * The test for the o_tty closing is necessary, since the master and
1597 * slave sides may close in any order. If the slave side closes out
1598 * first, its count will be one, since the master side holds an open.
1599 * Thus this test wouldn't be triggered at the time the slave closes,
1602 * Note that it's possible for the tty to be opened again while we're
1603 * flushing out waiters. By recalculating the closing flags before
1604 * each iteration we avoid any problems.
1607 /* Guard against races with tty->count changes elsewhere and
1608 opens on /dev/tty */
1610 mutex_lock(&tty_mutex);
1612 tty_closing = tty->count <= 1;
1613 o_tty_closing = o_tty &&
1614 (o_tty->count <= (pty_master ? 1 : 0));
1618 if (waitqueue_active(&tty->read_wait)) {
1619 wake_up_poll(&tty->read_wait, POLLIN);
1622 if (waitqueue_active(&tty->write_wait)) {
1623 wake_up_poll(&tty->write_wait, POLLOUT);
1627 if (o_tty_closing) {
1628 if (waitqueue_active(&o_tty->read_wait)) {
1629 wake_up_poll(&o_tty->read_wait, POLLIN);
1632 if (waitqueue_active(&o_tty->write_wait)) {
1633 wake_up_poll(&o_tty->write_wait, POLLOUT);
1640 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1641 "active!\n", tty_name(tty, buf));
1643 mutex_unlock(&tty_mutex);
1648 * The closing flags are now consistent with the open counts on
1649 * both sides, and we've completed the last operation that could
1650 * block, so it's safe to proceed with closing.
1653 if (--o_tty->count < 0) {
1654 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1656 o_tty->count, tty_name(o_tty, buf));
1660 if (--tty->count < 0) {
1661 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1662 tty->count, tty_name(tty, buf));
1667 * We've decremented tty->count, so we need to remove this file
1668 * descriptor off the tty->tty_files list; this serves two
1670 * - check_tty_count sees the correct number of file descriptors
1671 * associated with this tty.
1672 * - do_tty_hangup no longer sees this file descriptor as
1673 * something that needs to be handled for hangups.
1676 filp->private_data = NULL;
1679 * Perform some housekeeping before deciding whether to return.
1681 * Set the TTY_CLOSING flag if this was the last open. In the
1682 * case of a pty we may have to wait around for the other side
1683 * to close, and TTY_CLOSING makes sure we can't be reopened.
1686 set_bit(TTY_CLOSING, &tty->flags);
1688 set_bit(TTY_CLOSING, &o_tty->flags);
1691 * If _either_ side is closing, make sure there aren't any
1692 * processes that still think tty or o_tty is their controlling
1695 if (tty_closing || o_tty_closing) {
1696 read_lock(&tasklist_lock);
1697 session_clear_tty(tty->session);
1699 session_clear_tty(o_tty->session);
1700 read_unlock(&tasklist_lock);
1703 mutex_unlock(&tty_mutex);
1705 /* check whether both sides are closing ... */
1706 if (!tty_closing || (o_tty && !o_tty_closing)) {
1711 #ifdef TTY_DEBUG_HANGUP
1712 printk(KERN_DEBUG "freeing tty structure...");
1715 * Ask the line discipline code to release its structures
1717 tty_ldisc_release(tty, o_tty);
1719 * The release_tty function takes care of the details of clearing
1720 * the slots and preserving the termios structure.
1722 release_tty(tty, idx);
1724 /* Make this pty number available for reallocation */
1726 devpts_kill_index(inode, idx);
1732 * tty_open - open a tty device
1733 * @inode: inode of device file
1734 * @filp: file pointer to tty
1736 * tty_open and tty_release keep up the tty count that contains the
1737 * number of opens done on a tty. We cannot use the inode-count, as
1738 * different inodes might point to the same tty.
1740 * Open-counting is needed for pty masters, as well as for keeping
1741 * track of serial lines: DTR is dropped when the last close happens.
1742 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1744 * The termios state of a pty is reset on first open so that
1745 * settings don't persist across reuse.
1747 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1748 * tty->count should protect the rest.
1749 * ->siglock protects ->signal/->sighand
1752 static int tty_open(struct inode *inode, struct file *filp)
1754 struct tty_struct *tty = NULL;
1756 struct tty_driver *driver;
1758 dev_t device = inode->i_rdev;
1759 unsigned saved_flags = filp->f_flags;
1761 nonseekable_open(inode, filp);
1764 noctty = filp->f_flags & O_NOCTTY;
1768 mutex_lock(&tty_mutex);
1771 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1772 tty = get_current_tty();
1775 mutex_unlock(&tty_mutex);
1778 driver = tty_driver_kref_get(tty->driver);
1780 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1782 /* FIXME: Should we take a driver reference ? */
1787 if (device == MKDEV(TTY_MAJOR, 0)) {
1788 extern struct tty_driver *console_driver;
1789 driver = tty_driver_kref_get(console_driver);
1795 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1796 struct tty_driver *console_driver = console_device(&index);
1797 if (console_driver) {
1798 driver = tty_driver_kref_get(console_driver);
1800 /* Don't let /dev/console block */
1801 filp->f_flags |= O_NONBLOCK;
1807 mutex_unlock(&tty_mutex);
1811 driver = get_tty_driver(device, &index);
1814 mutex_unlock(&tty_mutex);
1819 /* check whether we're reopening an existing tty */
1820 tty = tty_driver_lookup_tty(driver, inode, index);
1824 mutex_unlock(&tty_mutex);
1825 return PTR_ERR(tty);
1830 retval = tty_reopen(tty);
1832 tty = ERR_PTR(retval);
1834 tty = tty_init_dev(driver, index, 0);
1836 mutex_unlock(&tty_mutex);
1837 tty_driver_kref_put(driver);
1840 return PTR_ERR(tty);
1843 filp->private_data = tty;
1844 file_move(filp, &tty->tty_files);
1845 check_tty_count(tty, "tty_open");
1846 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1847 tty->driver->subtype == PTY_TYPE_MASTER)
1849 #ifdef TTY_DEBUG_HANGUP
1850 printk(KERN_DEBUG "opening %s...", tty->name);
1854 retval = tty->ops->open(tty, filp);
1858 filp->f_flags = saved_flags;
1860 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1861 !capable(CAP_SYS_ADMIN))
1865 #ifdef TTY_DEBUG_HANGUP
1866 printk(KERN_DEBUG "error %d in opening %s...", retval,
1869 tty_release(inode, filp);
1870 if (retval != -ERESTARTSYS) {
1874 if (signal_pending(current)) {
1880 * Need to reset f_op in case a hangup happened.
1882 if (filp->f_op == &hung_up_tty_fops)
1883 filp->f_op = &tty_fops;
1890 mutex_lock(&tty_mutex);
1892 spin_lock_irq(¤t->sighand->siglock);
1894 current->signal->leader &&
1895 !current->signal->tty &&
1896 tty->session == NULL)
1897 __proc_set_tty(current, tty);
1898 spin_unlock_irq(¤t->sighand->siglock);
1900 mutex_unlock(&tty_mutex);
1907 * tty_poll - check tty status
1908 * @filp: file being polled
1909 * @wait: poll wait structures to update
1911 * Call the line discipline polling method to obtain the poll
1912 * status of the device.
1914 * Locking: locks called line discipline but ldisc poll method
1915 * may be re-entered freely by other callers.
1918 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1920 struct tty_struct *tty;
1921 struct tty_ldisc *ld;
1924 tty = (struct tty_struct *)filp->private_data;
1925 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1928 ld = tty_ldisc_ref_wait(tty);
1930 ret = (ld->ops->poll)(tty, filp, wait);
1931 tty_ldisc_deref(ld);
1935 static int __tty_fasync(int fd, struct file *filp, int on)
1937 struct tty_struct *tty;
1938 unsigned long flags;
1941 tty = (struct tty_struct *)filp->private_data;
1942 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1945 retval = fasync_helper(fd, filp, on, &tty->fasync);
1952 if (!waitqueue_active(&tty->read_wait))
1953 tty->minimum_to_wake = 1;
1954 spin_lock_irqsave(&tty->ctrl_lock, flags);
1957 type = PIDTYPE_PGID;
1959 pid = task_pid(current);
1963 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1964 retval = __f_setown(filp, pid, type, 0);
1969 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
1970 tty->minimum_to_wake = N_TTY_BUF_SIZE;
1977 static int tty_fasync(int fd, struct file *filp, int on)
1981 retval = __tty_fasync(fd, filp, on);
1987 * tiocsti - fake input character
1988 * @tty: tty to fake input into
1989 * @p: pointer to character
1991 * Fake input to a tty device. Does the necessary locking and
1994 * FIXME: does not honour flow control ??
1997 * Called functions take tty_ldisc_lock
1998 * current->signal->tty check is safe without locks
2000 * FIXME: may race normal receive processing
2003 static int tiocsti(struct tty_struct *tty, char __user *p)
2006 struct tty_ldisc *ld;
2008 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2010 if (get_user(ch, p))
2012 tty_audit_tiocsti(tty, ch);
2013 ld = tty_ldisc_ref_wait(tty);
2014 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2015 tty_ldisc_deref(ld);
2020 * tiocgwinsz - implement window query ioctl
2022 * @arg: user buffer for result
2024 * Copies the kernel idea of the window size into the user buffer.
2026 * Locking: tty->termios_mutex is taken to ensure the winsize data
2030 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2034 mutex_lock(&tty->termios_mutex);
2035 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2036 mutex_unlock(&tty->termios_mutex);
2038 return err ? -EFAULT: 0;
2042 * tty_do_resize - resize event
2043 * @tty: tty being resized
2044 * @rows: rows (character)
2045 * @cols: cols (character)
2047 * Update the termios variables and send the necessary signals to
2048 * peform a terminal resize correctly
2051 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2054 unsigned long flags;
2057 mutex_lock(&tty->termios_mutex);
2058 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2060 /* Get the PID values and reference them so we can
2061 avoid holding the tty ctrl lock while sending signals */
2062 spin_lock_irqsave(&tty->ctrl_lock, flags);
2063 pgrp = get_pid(tty->pgrp);
2064 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2067 kill_pgrp(pgrp, SIGWINCH, 1);
2072 mutex_unlock(&tty->termios_mutex);
2077 * tiocswinsz - implement window size set ioctl
2078 * @tty; tty side of tty
2079 * @arg: user buffer for result
2081 * Copies the user idea of the window size to the kernel. Traditionally
2082 * this is just advisory information but for the Linux console it
2083 * actually has driver level meaning and triggers a VC resize.
2086 * Driver dependant. The default do_resize method takes the
2087 * tty termios mutex and ctrl_lock. The console takes its own lock
2088 * then calls into the default method.
2091 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2093 struct winsize tmp_ws;
2094 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2097 if (tty->ops->resize)
2098 return tty->ops->resize(tty, &tmp_ws);
2100 return tty_do_resize(tty, &tmp_ws);
2104 * tioccons - allow admin to move logical console
2105 * @file: the file to become console
2107 * Allow the adminstrator to move the redirected console device
2109 * Locking: uses redirect_lock to guard the redirect information
2112 static int tioccons(struct file *file)
2114 if (!capable(CAP_SYS_ADMIN))
2116 if (file->f_op->write == redirected_tty_write) {
2118 spin_lock(&redirect_lock);
2121 spin_unlock(&redirect_lock);
2126 spin_lock(&redirect_lock);
2128 spin_unlock(&redirect_lock);
2133 spin_unlock(&redirect_lock);
2138 * fionbio - non blocking ioctl
2139 * @file: file to set blocking value
2140 * @p: user parameter
2142 * Historical tty interfaces had a blocking control ioctl before
2143 * the generic functionality existed. This piece of history is preserved
2144 * in the expected tty API of posix OS's.
2146 * Locking: none, the open file handle ensures it won't go away.
2149 static int fionbio(struct file *file, int __user *p)
2153 if (get_user(nonblock, p))
2156 spin_lock(&file->f_lock);
2158 file->f_flags |= O_NONBLOCK;
2160 file->f_flags &= ~O_NONBLOCK;
2161 spin_unlock(&file->f_lock);
2166 * tiocsctty - set controlling tty
2167 * @tty: tty structure
2168 * @arg: user argument
2170 * This ioctl is used to manage job control. It permits a session
2171 * leader to set this tty as the controlling tty for the session.
2174 * Takes tty_mutex() to protect tty instance
2175 * Takes tasklist_lock internally to walk sessions
2176 * Takes ->siglock() when updating signal->tty
2179 static int tiocsctty(struct tty_struct *tty, int arg)
2182 if (current->signal->leader && (task_session(current) == tty->session))
2185 mutex_lock(&tty_mutex);
2187 * The process must be a session leader and
2188 * not have a controlling tty already.
2190 if (!current->signal->leader || current->signal->tty) {
2197 * This tty is already the controlling
2198 * tty for another session group!
2200 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2204 read_lock(&tasklist_lock);
2205 session_clear_tty(tty->session);
2206 read_unlock(&tasklist_lock);
2212 proc_set_tty(current, tty);
2214 mutex_unlock(&tty_mutex);
2219 * tty_get_pgrp - return a ref counted pgrp pid
2222 * Returns a refcounted instance of the pid struct for the process
2223 * group controlling the tty.
2226 struct pid *tty_get_pgrp(struct tty_struct *tty)
2228 unsigned long flags;
2231 spin_lock_irqsave(&tty->ctrl_lock, flags);
2232 pgrp = get_pid(tty->pgrp);
2233 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2237 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2240 * tiocgpgrp - get process group
2241 * @tty: tty passed by user
2242 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2245 * Obtain the process group of the tty. If there is no process group
2248 * Locking: none. Reference to current->signal->tty is safe.
2251 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2256 * (tty == real_tty) is a cheap way of
2257 * testing if the tty is NOT a master pty.
2259 if (tty == real_tty && current->signal->tty != real_tty)
2261 pid = tty_get_pgrp(real_tty);
2262 ret = put_user(pid_vnr(pid), p);
2268 * tiocspgrp - attempt to set process group
2269 * @tty: tty passed by user
2270 * @real_tty: tty side device matching tty passed by user
2273 * Set the process group of the tty to the session passed. Only
2274 * permitted where the tty session is our session.
2276 * Locking: RCU, ctrl lock
2279 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2283 int retval = tty_check_change(real_tty);
2284 unsigned long flags;
2290 if (!current->signal->tty ||
2291 (current->signal->tty != real_tty) ||
2292 (real_tty->session != task_session(current)))
2294 if (get_user(pgrp_nr, p))
2299 pgrp = find_vpid(pgrp_nr);
2304 if (session_of_pgrp(pgrp) != task_session(current))
2307 spin_lock_irqsave(&tty->ctrl_lock, flags);
2308 put_pid(real_tty->pgrp);
2309 real_tty->pgrp = get_pid(pgrp);
2310 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2317 * tiocgsid - get session id
2318 * @tty: tty passed by user
2319 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2320 * @p: pointer to returned session id
2322 * Obtain the session id of the tty. If there is no session
2325 * Locking: none. Reference to current->signal->tty is safe.
2328 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2331 * (tty == real_tty) is a cheap way of
2332 * testing if the tty is NOT a master pty.
2334 if (tty == real_tty && current->signal->tty != real_tty)
2336 if (!real_tty->session)
2338 return put_user(pid_vnr(real_tty->session), p);
2342 * tiocsetd - set line discipline
2344 * @p: pointer to user data
2346 * Set the line discipline according to user request.
2348 * Locking: see tty_set_ldisc, this function is just a helper
2351 static int tiocsetd(struct tty_struct *tty, int __user *p)
2356 if (get_user(ldisc, p))
2359 ret = tty_set_ldisc(tty, ldisc);
2365 * send_break - performed time break
2366 * @tty: device to break on
2367 * @duration: timeout in mS
2369 * Perform a timed break on hardware that lacks its own driver level
2370 * timed break functionality.
2373 * atomic_write_lock serializes
2377 static int send_break(struct tty_struct *tty, unsigned int duration)
2381 if (tty->ops->break_ctl == NULL)
2384 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2385 retval = tty->ops->break_ctl(tty, duration);
2387 /* Do the work ourselves */
2388 if (tty_write_lock(tty, 0) < 0)
2390 retval = tty->ops->break_ctl(tty, -1);
2393 if (!signal_pending(current))
2394 msleep_interruptible(duration);
2395 retval = tty->ops->break_ctl(tty, 0);
2397 tty_write_unlock(tty);
2398 if (signal_pending(current))
2405 * tty_tiocmget - get modem status
2407 * @file: user file pointer
2408 * @p: pointer to result
2410 * Obtain the modem status bits from the tty driver if the feature
2411 * is supported. Return -EINVAL if it is not available.
2413 * Locking: none (up to the driver)
2416 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2418 int retval = -EINVAL;
2420 if (tty->ops->tiocmget) {
2421 retval = tty->ops->tiocmget(tty, file);
2424 retval = put_user(retval, p);
2430 * tty_tiocmset - set modem status
2432 * @file: user file pointer
2433 * @cmd: command - clear bits, set bits or set all
2434 * @p: pointer to desired bits
2436 * Set the modem status bits from the tty driver if the feature
2437 * is supported. Return -EINVAL if it is not available.
2439 * Locking: none (up to the driver)
2442 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2446 unsigned int set, clear, val;
2448 if (tty->ops->tiocmset == NULL)
2451 retval = get_user(val, p);
2467 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2468 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2469 return tty->ops->tiocmset(tty, file, set, clear);
2472 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2474 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2475 tty->driver->subtype == PTY_TYPE_MASTER)
2479 EXPORT_SYMBOL(tty_pair_get_tty);
2481 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2483 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2484 tty->driver->subtype == PTY_TYPE_MASTER)
2488 EXPORT_SYMBOL(tty_pair_get_pty);
2491 * Split this up, as gcc can choke on it otherwise..
2493 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2495 struct tty_struct *tty, *real_tty;
2496 void __user *p = (void __user *)arg;
2498 struct tty_ldisc *ld;
2499 struct inode *inode = file->f_dentry->d_inode;
2501 tty = (struct tty_struct *)file->private_data;
2502 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2505 real_tty = tty_pair_get_tty(tty);
2508 * Factor out some common prep work
2516 retval = tty_check_change(tty);
2519 if (cmd != TIOCCBRK) {
2520 tty_wait_until_sent(tty, 0);
2521 if (signal_pending(current))
2532 return tiocsti(tty, p);
2534 return tiocgwinsz(real_tty, p);
2536 return tiocswinsz(real_tty, p);
2538 return real_tty != tty ? -EINVAL : tioccons(file);
2540 return fionbio(file, p);
2542 set_bit(TTY_EXCLUSIVE, &tty->flags);
2545 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2548 if (current->signal->tty != tty)
2553 return tiocsctty(tty, arg);
2555 return tiocgpgrp(tty, real_tty, p);
2557 return tiocspgrp(tty, real_tty, p);
2559 return tiocgsid(tty, real_tty, p);
2561 return put_user(tty->ldisc->ops->num, (int __user *)p);
2563 return tiocsetd(tty, p);
2567 case TIOCSBRK: /* Turn break on, unconditionally */
2568 if (tty->ops->break_ctl)
2569 return tty->ops->break_ctl(tty, -1);
2571 case TIOCCBRK: /* Turn break off, unconditionally */
2572 if (tty->ops->break_ctl)
2573 return tty->ops->break_ctl(tty, 0);
2575 case TCSBRK: /* SVID version: non-zero arg --> no break */
2576 /* non-zero arg means wait for all output data
2577 * to be sent (performed above) but don't send break.
2578 * This is used by the tcdrain() termios function.
2581 return send_break(tty, 250);
2583 case TCSBRKP: /* support for POSIX tcsendbreak() */
2584 return send_break(tty, arg ? arg*100 : 250);
2587 return tty_tiocmget(tty, file, p);
2591 return tty_tiocmset(tty, file, cmd, p);
2596 /* flush tty buffer and allow ldisc to process ioctl */
2597 tty_buffer_flush(tty);
2602 if (tty->ops->ioctl) {
2603 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2604 if (retval != -ENOIOCTLCMD)
2607 ld = tty_ldisc_ref_wait(tty);
2609 if (ld->ops->ioctl) {
2610 retval = ld->ops->ioctl(tty, file, cmd, arg);
2611 if (retval == -ENOIOCTLCMD)
2614 tty_ldisc_deref(ld);
2618 #ifdef CONFIG_COMPAT
2619 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2622 struct inode *inode = file->f_dentry->d_inode;
2623 struct tty_struct *tty = file->private_data;
2624 struct tty_ldisc *ld;
2625 int retval = -ENOIOCTLCMD;
2627 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2630 if (tty->ops->compat_ioctl) {
2631 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2632 if (retval != -ENOIOCTLCMD)
2636 ld = tty_ldisc_ref_wait(tty);
2637 if (ld->ops->compat_ioctl)
2638 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2639 tty_ldisc_deref(ld);
2646 * This implements the "Secure Attention Key" --- the idea is to
2647 * prevent trojan horses by killing all processes associated with this
2648 * tty when the user hits the "Secure Attention Key". Required for
2649 * super-paranoid applications --- see the Orange Book for more details.
2651 * This code could be nicer; ideally it should send a HUP, wait a few
2652 * seconds, then send a INT, and then a KILL signal. But you then
2653 * have to coordinate with the init process, since all processes associated
2654 * with the current tty must be dead before the new getty is allowed
2657 * Now, if it would be correct ;-/ The current code has a nasty hole -
2658 * it doesn't catch files in flight. We may send the descriptor to ourselves
2659 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2661 * Nasty bug: do_SAK is being called in interrupt context. This can
2662 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2664 void __do_SAK(struct tty_struct *tty)
2669 struct task_struct *g, *p;
2670 struct pid *session;
2673 struct fdtable *fdt;
2677 session = tty->session;
2679 tty_ldisc_flush(tty);
2681 tty_driver_flush_buffer(tty);
2683 read_lock(&tasklist_lock);
2684 /* Kill the entire session */
2685 do_each_pid_task(session, PIDTYPE_SID, p) {
2686 printk(KERN_NOTICE "SAK: killed process %d"
2687 " (%s): task_session(p)==tty->session\n",
2688 task_pid_nr(p), p->comm);
2689 send_sig(SIGKILL, p, 1);
2690 } while_each_pid_task(session, PIDTYPE_SID, p);
2691 /* Now kill any processes that happen to have the
2694 do_each_thread(g, p) {
2695 if (p->signal->tty == tty) {
2696 printk(KERN_NOTICE "SAK: killed process %d"
2697 " (%s): task_session(p)==tty->session\n",
2698 task_pid_nr(p), p->comm);
2699 send_sig(SIGKILL, p, 1);
2705 * We don't take a ref to the file, so we must
2706 * hold ->file_lock instead.
2708 spin_lock(&p->files->file_lock);
2709 fdt = files_fdtable(p->files);
2710 for (i = 0; i < fdt->max_fds; i++) {
2711 filp = fcheck_files(p->files, i);
2714 if (filp->f_op->read == tty_read &&
2715 filp->private_data == tty) {
2716 printk(KERN_NOTICE "SAK: killed process %d"
2717 " (%s): fd#%d opened to the tty\n",
2718 task_pid_nr(p), p->comm, i);
2719 force_sig(SIGKILL, p);
2723 spin_unlock(&p->files->file_lock);
2726 } while_each_thread(g, p);
2727 read_unlock(&tasklist_lock);
2731 static void do_SAK_work(struct work_struct *work)
2733 struct tty_struct *tty =
2734 container_of(work, struct tty_struct, SAK_work);
2739 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2740 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2741 * the values which we write to it will be identical to the values which it
2742 * already has. --akpm
2744 void do_SAK(struct tty_struct *tty)
2748 schedule_work(&tty->SAK_work);
2751 EXPORT_SYMBOL(do_SAK);
2754 * initialize_tty_struct
2755 * @tty: tty to initialize
2757 * This subroutine initializes a tty structure that has been newly
2760 * Locking: none - tty in question must not be exposed at this point
2763 void initialize_tty_struct(struct tty_struct *tty,
2764 struct tty_driver *driver, int idx)
2766 memset(tty, 0, sizeof(struct tty_struct));
2767 kref_init(&tty->kref);
2768 tty->magic = TTY_MAGIC;
2769 tty_ldisc_init(tty);
2770 tty->session = NULL;
2772 tty->overrun_time = jiffies;
2773 tty->buf.head = tty->buf.tail = NULL;
2774 tty_buffer_init(tty);
2775 mutex_init(&tty->termios_mutex);
2776 mutex_init(&tty->ldisc_mutex);
2777 init_waitqueue_head(&tty->write_wait);
2778 init_waitqueue_head(&tty->read_wait);
2779 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2780 mutex_init(&tty->atomic_read_lock);
2781 mutex_init(&tty->atomic_write_lock);
2782 mutex_init(&tty->output_lock);
2783 mutex_init(&tty->echo_lock);
2784 spin_lock_init(&tty->read_lock);
2785 spin_lock_init(&tty->ctrl_lock);
2786 INIT_LIST_HEAD(&tty->tty_files);
2787 INIT_WORK(&tty->SAK_work, do_SAK_work);
2789 tty->driver = driver;
2790 tty->ops = driver->ops;
2792 tty_line_name(driver, idx, tty->name);
2796 * tty_put_char - write one character to a tty
2800 * Write one byte to the tty using the provided put_char method
2801 * if present. Returns the number of characters successfully output.
2803 * Note: the specific put_char operation in the driver layer may go
2804 * away soon. Don't call it directly, use this method
2807 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2809 if (tty->ops->put_char)
2810 return tty->ops->put_char(tty, ch);
2811 return tty->ops->write(tty, &ch, 1);
2813 EXPORT_SYMBOL_GPL(tty_put_char);
2815 struct class *tty_class;
2818 * tty_register_device - register a tty device
2819 * @driver: the tty driver that describes the tty device
2820 * @index: the index in the tty driver for this tty device
2821 * @device: a struct device that is associated with this tty device.
2822 * This field is optional, if there is no known struct device
2823 * for this tty device it can be set to NULL safely.
2825 * Returns a pointer to the struct device for this tty device
2826 * (or ERR_PTR(-EFOO) on error).
2828 * This call is required to be made to register an individual tty device
2829 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2830 * that bit is not set, this function should not be called by a tty
2836 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2837 struct device *device)
2840 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2842 if (index >= driver->num) {
2843 printk(KERN_ERR "Attempt to register invalid tty line number "
2845 return ERR_PTR(-EINVAL);
2848 if (driver->type == TTY_DRIVER_TYPE_PTY)
2849 pty_line_name(driver, index, name);
2851 tty_line_name(driver, index, name);
2853 return device_create(tty_class, device, dev, NULL, name);
2855 EXPORT_SYMBOL(tty_register_device);
2858 * tty_unregister_device - unregister a tty device
2859 * @driver: the tty driver that describes the tty device
2860 * @index: the index in the tty driver for this tty device
2862 * If a tty device is registered with a call to tty_register_device() then
2863 * this function must be called when the tty device is gone.
2868 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2870 device_destroy(tty_class,
2871 MKDEV(driver->major, driver->minor_start) + index);
2873 EXPORT_SYMBOL(tty_unregister_device);
2875 struct tty_driver *alloc_tty_driver(int lines)
2877 struct tty_driver *driver;
2879 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2881 kref_init(&driver->kref);
2882 driver->magic = TTY_DRIVER_MAGIC;
2883 driver->num = lines;
2884 /* later we'll move allocation of tables here */
2888 EXPORT_SYMBOL(alloc_tty_driver);
2890 static void destruct_tty_driver(struct kref *kref)
2892 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2894 struct ktermios *tp;
2897 if (driver->flags & TTY_DRIVER_INSTALLED) {
2899 * Free the termios and termios_locked structures because
2900 * we don't want to get memory leaks when modular tty
2901 * drivers are removed from the kernel.
2903 for (i = 0; i < driver->num; i++) {
2904 tp = driver->termios[i];
2906 driver->termios[i] = NULL;
2909 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2910 tty_unregister_device(driver, i);
2913 proc_tty_unregister_driver(driver);
2914 driver->ttys = NULL;
2915 driver->termios = NULL;
2917 cdev_del(&driver->cdev);
2922 void tty_driver_kref_put(struct tty_driver *driver)
2924 kref_put(&driver->kref, destruct_tty_driver);
2926 EXPORT_SYMBOL(tty_driver_kref_put);
2928 void tty_set_operations(struct tty_driver *driver,
2929 const struct tty_operations *op)
2933 EXPORT_SYMBOL(tty_set_operations);
2935 void put_tty_driver(struct tty_driver *d)
2937 tty_driver_kref_put(d);
2939 EXPORT_SYMBOL(put_tty_driver);
2942 * Called by a tty driver to register itself.
2944 int tty_register_driver(struct tty_driver *driver)
2951 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2952 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2957 if (!driver->major) {
2958 error = alloc_chrdev_region(&dev, driver->minor_start,
2959 driver->num, driver->name);
2961 driver->major = MAJOR(dev);
2962 driver->minor_start = MINOR(dev);
2965 dev = MKDEV(driver->major, driver->minor_start);
2966 error = register_chrdev_region(dev, driver->num, driver->name);
2974 driver->ttys = (struct tty_struct **)p;
2975 driver->termios = (struct ktermios **)(p + driver->num);
2977 driver->ttys = NULL;
2978 driver->termios = NULL;
2981 cdev_init(&driver->cdev, &tty_fops);
2982 driver->cdev.owner = driver->owner;
2983 error = cdev_add(&driver->cdev, dev, driver->num);
2985 unregister_chrdev_region(dev, driver->num);
2986 driver->ttys = NULL;
2987 driver->termios = NULL;
2992 mutex_lock(&tty_mutex);
2993 list_add(&driver->tty_drivers, &tty_drivers);
2994 mutex_unlock(&tty_mutex);
2996 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
2997 for (i = 0; i < driver->num; i++)
2998 tty_register_device(driver, i, NULL);
3000 proc_tty_register_driver(driver);
3001 driver->flags |= TTY_DRIVER_INSTALLED;
3005 EXPORT_SYMBOL(tty_register_driver);
3008 * Called by a tty driver to unregister itself.
3010 int tty_unregister_driver(struct tty_driver *driver)
3014 if (driver->refcount)
3017 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3019 mutex_lock(&tty_mutex);
3020 list_del(&driver->tty_drivers);
3021 mutex_unlock(&tty_mutex);
3025 EXPORT_SYMBOL(tty_unregister_driver);
3027 dev_t tty_devnum(struct tty_struct *tty)
3029 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3031 EXPORT_SYMBOL(tty_devnum);
3033 void proc_clear_tty(struct task_struct *p)
3035 unsigned long flags;
3036 struct tty_struct *tty;
3037 spin_lock_irqsave(&p->sighand->siglock, flags);
3038 tty = p->signal->tty;
3039 p->signal->tty = NULL;
3040 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3044 /* Called under the sighand lock */
3046 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3049 unsigned long flags;
3050 /* We should not have a session or pgrp to put here but.... */
3051 spin_lock_irqsave(&tty->ctrl_lock, flags);
3052 put_pid(tty->session);
3054 tty->pgrp = get_pid(task_pgrp(tsk));
3055 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3056 tty->session = get_pid(task_session(tsk));
3057 if (tsk->signal->tty) {
3058 printk(KERN_DEBUG "tty not NULL!!\n");
3059 tty_kref_put(tsk->signal->tty);
3062 put_pid(tsk->signal->tty_old_pgrp);
3063 tsk->signal->tty = tty_kref_get(tty);
3064 tsk->signal->tty_old_pgrp = NULL;
3067 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3069 spin_lock_irq(&tsk->sighand->siglock);
3070 __proc_set_tty(tsk, tty);
3071 spin_unlock_irq(&tsk->sighand->siglock);
3074 struct tty_struct *get_current_tty(void)
3076 struct tty_struct *tty;
3077 unsigned long flags;
3079 spin_lock_irqsave(¤t->sighand->siglock, flags);
3080 tty = tty_kref_get(current->signal->tty);
3081 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3084 EXPORT_SYMBOL_GPL(get_current_tty);
3086 void tty_default_fops(struct file_operations *fops)
3092 * Initialize the console device. This is called *early*, so
3093 * we can't necessarily depend on lots of kernel help here.
3094 * Just do some early initializations, and do the complex setup
3097 void __init console_init(void)
3101 /* Setup the default TTY line discipline. */
3105 * set up the console device so that later boot sequences can
3106 * inform about problems etc..
3108 call = __con_initcall_start;
3109 while (call < __con_initcall_end) {
3115 static char *tty_devnode(struct device *dev, mode_t *mode)
3119 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3120 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3125 static int __init tty_class_init(void)
3127 tty_class = class_create(THIS_MODULE, "tty");
3128 if (IS_ERR(tty_class))
3129 return PTR_ERR(tty_class);
3130 tty_class->devnode = tty_devnode;
3134 postcore_initcall(tty_class_init);
3136 /* 3/2004 jmc: why do these devices exist? */
3138 static struct cdev tty_cdev, console_cdev;
3141 * Ok, now we can initialize the rest of the tty devices and can count
3142 * on memory allocations, interrupts etc..
3144 int __init tty_init(void)
3146 cdev_init(&tty_cdev, &tty_fops);
3147 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3148 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3149 panic("Couldn't register /dev/tty driver\n");
3150 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3153 cdev_init(&console_cdev, &console_fops);
3154 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3155 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3156 panic("Couldn't register /dev/console driver\n");
3157 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3161 vty_init(&console_fops);