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 * __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 void __tty_hangup(struct tty_struct *tty)
497 struct file *cons_filp = NULL;
498 struct file *filp, *f = NULL;
499 struct task_struct *p;
500 int closecount = 0, n;
508 spin_lock(&redirect_lock);
509 if (redirect && redirect->private_data == tty) {
513 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 check_tty_count(tty, "tty_hangup");
523 /* This breaks for file handles being sent over AF_UNIX sockets ? */
524 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
525 if (filp->f_op->write == redirected_tty_write)
527 if (filp->f_op->write != tty_write)
530 __tty_fasync(-1, filp, 0); /* can't block */
531 filp->f_op = &hung_up_tty_fops;
535 tty_ldisc_hangup(tty);
537 read_lock(&tasklist_lock);
539 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
540 spin_lock_irq(&p->sighand->siglock);
541 if (p->signal->tty == tty) {
542 p->signal->tty = NULL;
543 /* We defer the dereferences outside fo
547 if (!p->signal->leader) {
548 spin_unlock_irq(&p->sighand->siglock);
551 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
552 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
553 put_pid(p->signal->tty_old_pgrp); /* A noop */
554 spin_lock_irqsave(&tty->ctrl_lock, flags);
556 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
557 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
558 spin_unlock_irq(&p->sighand->siglock);
559 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
561 read_unlock(&tasklist_lock);
563 spin_lock_irqsave(&tty->ctrl_lock, flags);
564 clear_bit(TTY_THROTTLED, &tty->flags);
565 clear_bit(TTY_PUSH, &tty->flags);
566 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
567 put_pid(tty->session);
571 tty->ctrl_status = 0;
572 set_bit(TTY_HUPPED, &tty->flags);
573 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
575 /* Account for the p->signal references we killed */
580 * If one of the devices matches a console pointer, we
581 * cannot just call hangup() because that will cause
582 * tty->count and state->count to go out of sync.
583 * So we just call close() the right number of times.
587 for (n = 0; n < closecount; n++)
588 tty->ops->close(tty, cons_filp);
589 } else if (tty->ops->hangup)
590 (tty->ops->hangup)(tty);
592 * We don't want to have driver/ldisc interactions beyond
593 * the ones we did here. The driver layer expects no
594 * calls after ->hangup() from the ldisc side. However we
595 * can't yet guarantee all that.
597 set_bit(TTY_HUPPED, &tty->flags);
598 tty_ldisc_enable(tty);
606 static void do_tty_hangup(struct work_struct *work)
608 struct tty_struct *tty =
609 container_of(work, struct tty_struct, hangup_work);
615 * tty_hangup - trigger a hangup event
616 * @tty: tty to hangup
618 * A carrier loss (virtual or otherwise) has occurred on this like
619 * schedule a hangup sequence to run after this event.
622 void tty_hangup(struct tty_struct *tty)
624 #ifdef TTY_DEBUG_HANGUP
626 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
628 schedule_work(&tty->hangup_work);
631 EXPORT_SYMBOL(tty_hangup);
634 * tty_vhangup - process vhangup
635 * @tty: tty to hangup
637 * The user has asked via system call for the terminal to be hung up.
638 * We do this synchronously so that when the syscall returns the process
639 * is complete. That guarantee is necessary for security reasons.
642 void tty_vhangup(struct tty_struct *tty)
644 #ifdef TTY_DEBUG_HANGUP
647 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
652 EXPORT_SYMBOL(tty_vhangup);
656 * tty_vhangup_self - process vhangup for own ctty
658 * Perform a vhangup on the current controlling tty
661 void tty_vhangup_self(void)
663 struct tty_struct *tty;
665 tty = get_current_tty();
673 * tty_hung_up_p - was tty hung up
674 * @filp: file pointer of tty
676 * Return true if the tty has been subject to a vhangup or a carrier
680 int tty_hung_up_p(struct file *filp)
682 return (filp->f_op == &hung_up_tty_fops);
685 EXPORT_SYMBOL(tty_hung_up_p);
687 static void session_clear_tty(struct pid *session)
689 struct task_struct *p;
690 do_each_pid_task(session, PIDTYPE_SID, p) {
692 } while_each_pid_task(session, PIDTYPE_SID, p);
696 * disassociate_ctty - disconnect controlling tty
697 * @on_exit: true if exiting so need to "hang up" the session
699 * This function is typically called only by the session leader, when
700 * it wants to disassociate itself from its controlling tty.
702 * It performs the following functions:
703 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
704 * (2) Clears the tty from being controlling the session
705 * (3) Clears the controlling tty for all processes in the
708 * The argument on_exit is set to 1 if called when a process is
709 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
712 * BTM is taken for hysterical raisins, and held when
713 * called from no_tty().
714 * tty_mutex is taken to protect tty
715 * ->siglock is taken to protect ->signal/->sighand
716 * tasklist_lock is taken to walk process list for sessions
717 * ->siglock is taken to protect ->signal/->sighand
720 void disassociate_ctty(int on_exit)
722 struct tty_struct *tty;
723 struct pid *tty_pgrp = NULL;
725 if (!current->signal->leader)
728 tty = get_current_tty();
730 tty_pgrp = get_pid(tty->pgrp);
732 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
736 } else if (on_exit) {
737 struct pid *old_pgrp;
738 spin_lock_irq(¤t->sighand->siglock);
739 old_pgrp = current->signal->tty_old_pgrp;
740 current->signal->tty_old_pgrp = NULL;
741 spin_unlock_irq(¤t->sighand->siglock);
743 kill_pgrp(old_pgrp, SIGHUP, on_exit);
744 kill_pgrp(old_pgrp, SIGCONT, on_exit);
750 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
752 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
756 spin_lock_irq(¤t->sighand->siglock);
757 put_pid(current->signal->tty_old_pgrp);
758 current->signal->tty_old_pgrp = NULL;
759 spin_unlock_irq(¤t->sighand->siglock);
761 tty = get_current_tty();
764 spin_lock_irqsave(&tty->ctrl_lock, flags);
765 put_pid(tty->session);
769 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
772 #ifdef TTY_DEBUG_HANGUP
773 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
778 /* Now clear signal->tty under the lock */
779 read_lock(&tasklist_lock);
780 session_clear_tty(task_session(current));
781 read_unlock(&tasklist_lock);
786 * no_tty - Ensure the current process does not have a controlling tty
790 struct task_struct *tsk = current;
792 disassociate_ctty(0);
799 * stop_tty - propagate flow control
802 * Perform flow control to the driver. For PTY/TTY pairs we
803 * must also propagate the TIOCKPKT status. May be called
804 * on an already stopped device and will not re-call the driver
807 * This functionality is used by both the line disciplines for
808 * halting incoming flow and by the driver. It may therefore be
809 * called from any context, may be under the tty atomic_write_lock
813 * Uses the tty control lock internally
816 void stop_tty(struct tty_struct *tty)
819 spin_lock_irqsave(&tty->ctrl_lock, flags);
821 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
825 if (tty->link && tty->link->packet) {
826 tty->ctrl_status &= ~TIOCPKT_START;
827 tty->ctrl_status |= TIOCPKT_STOP;
828 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
830 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
832 (tty->ops->stop)(tty);
835 EXPORT_SYMBOL(stop_tty);
838 * start_tty - propagate flow control
841 * Start a tty that has been stopped if at all possible. Perform
842 * any necessary wakeups and propagate the TIOCPKT status. If this
843 * is the tty was previous stopped and is being started then the
844 * driver start method is invoked and the line discipline woken.
850 void start_tty(struct tty_struct *tty)
853 spin_lock_irqsave(&tty->ctrl_lock, flags);
854 if (!tty->stopped || tty->flow_stopped) {
855 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
859 if (tty->link && tty->link->packet) {
860 tty->ctrl_status &= ~TIOCPKT_STOP;
861 tty->ctrl_status |= TIOCPKT_START;
862 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
864 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
866 (tty->ops->start)(tty);
867 /* If we have a running line discipline it may need kicking */
871 EXPORT_SYMBOL(start_tty);
874 * tty_read - read method for tty device files
875 * @file: pointer to tty file
877 * @count: size of user buffer
880 * Perform the read system call function on this terminal device. Checks
881 * for hung up devices before calling the line discipline method.
884 * Locks the line discipline internally while needed. Multiple
885 * read calls may be outstanding in parallel.
888 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
892 struct tty_struct *tty;
894 struct tty_ldisc *ld;
896 tty = file->private_data;
897 inode = file->f_path.dentry->d_inode;
898 if (tty_paranoia_check(tty, inode, "tty_read"))
900 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
903 /* We want to wait for the line discipline to sort out in this
905 ld = tty_ldisc_ref_wait(tty);
907 i = (ld->ops->read)(tty, file, buf, count);
912 inode->i_atime = current_fs_time(inode->i_sb);
916 void tty_write_unlock(struct tty_struct *tty)
918 mutex_unlock(&tty->atomic_write_lock);
919 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
922 int tty_write_lock(struct tty_struct *tty, int ndelay)
924 if (!mutex_trylock(&tty->atomic_write_lock)) {
927 if (mutex_lock_interruptible(&tty->atomic_write_lock))
934 * Split writes up in sane blocksizes to avoid
935 * denial-of-service type attacks
937 static inline ssize_t do_tty_write(
938 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
939 struct tty_struct *tty,
941 const char __user *buf,
944 ssize_t ret, written = 0;
947 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
952 * We chunk up writes into a temporary buffer. This
953 * simplifies low-level drivers immensely, since they
954 * don't have locking issues and user mode accesses.
956 * But if TTY_NO_WRITE_SPLIT is set, we should use a
959 * The default chunk-size is 2kB, because the NTTY
960 * layer has problems with bigger chunks. It will
961 * claim to be able to handle more characters than
964 * FIXME: This can probably go away now except that 64K chunks
965 * are too likely to fail unless switched to vmalloc...
968 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
973 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
974 if (tty->write_cnt < chunk) {
975 unsigned char *buf_chunk;
980 buf_chunk = kmalloc(chunk, GFP_KERNEL);
985 kfree(tty->write_buf);
986 tty->write_cnt = chunk;
987 tty->write_buf = buf_chunk;
990 /* Do the write .. */
996 if (copy_from_user(tty->write_buf, buf, size))
998 ret = write(tty, file, tty->write_buf, size);
1007 if (signal_pending(current))
1012 struct inode *inode = file->f_path.dentry->d_inode;
1013 inode->i_mtime = current_fs_time(inode->i_sb);
1017 tty_write_unlock(tty);
1022 * tty_write_message - write a message to a certain tty, not just the console.
1023 * @tty: the destination tty_struct
1024 * @msg: the message to write
1026 * This is used for messages that need to be redirected to a specific tty.
1027 * We don't put it into the syslog queue right now maybe in the future if
1030 * We must still hold the BTM and test the CLOSING flag for the moment.
1033 void tty_write_message(struct tty_struct *tty, char *msg)
1036 mutex_lock(&tty->atomic_write_lock);
1038 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1040 tty->ops->write(tty, msg, strlen(msg));
1043 tty_write_unlock(tty);
1050 * tty_write - write method for tty device file
1051 * @file: tty file pointer
1052 * @buf: user data to write
1053 * @count: bytes to write
1056 * Write data to a tty device via the line discipline.
1059 * Locks the line discipline as required
1060 * Writes to the tty driver are serialized by the atomic_write_lock
1061 * and are then processed in chunks to the device. The line discipline
1062 * write method will not be invoked in parallel for each device.
1065 static ssize_t tty_write(struct file *file, const char __user *buf,
1066 size_t count, loff_t *ppos)
1068 struct tty_struct *tty;
1069 struct inode *inode = file->f_path.dentry->d_inode;
1071 struct tty_ldisc *ld;
1073 tty = file->private_data;
1074 if (tty_paranoia_check(tty, inode, "tty_write"))
1076 if (!tty || !tty->ops->write ||
1077 (test_bit(TTY_IO_ERROR, &tty->flags)))
1079 /* Short term debug to catch buggy drivers */
1080 if (tty->ops->write_room == NULL)
1081 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1083 ld = tty_ldisc_ref_wait(tty);
1084 if (!ld->ops->write)
1087 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1088 tty_ldisc_deref(ld);
1092 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1093 size_t count, loff_t *ppos)
1095 struct file *p = NULL;
1097 spin_lock(&redirect_lock);
1102 spin_unlock(&redirect_lock);
1106 res = vfs_write(p, buf, count, &p->f_pos);
1110 return tty_write(file, buf, count, ppos);
1113 static char ptychar[] = "pqrstuvwxyzabcde";
1116 * pty_line_name - generate name for a pty
1117 * @driver: the tty driver in use
1118 * @index: the minor number
1119 * @p: output buffer of at least 6 bytes
1121 * Generate a name from a driver reference and write it to the output
1126 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1128 int i = index + driver->name_base;
1129 /* ->name is initialized to "ttyp", but "tty" is expected */
1130 sprintf(p, "%s%c%x",
1131 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1132 ptychar[i >> 4 & 0xf], i & 0xf);
1136 * tty_line_name - generate name for a tty
1137 * @driver: the tty driver in use
1138 * @index: the minor number
1139 * @p: output buffer of at least 7 bytes
1141 * Generate a name from a driver reference and write it to the output
1146 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1148 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1152 * tty_driver_lookup_tty() - find an existing tty, if any
1153 * @driver: the driver for the tty
1154 * @idx: the minor number
1156 * Return the tty, if found or ERR_PTR() otherwise.
1158 * Locking: tty_mutex must be held. If tty is found, the mutex must
1159 * be held until the 'fast-open' is also done. Will change once we
1160 * have refcounting in the driver and per driver locking
1162 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1163 struct inode *inode, int idx)
1165 struct tty_struct *tty;
1167 if (driver->ops->lookup)
1168 return driver->ops->lookup(driver, inode, idx);
1170 tty = driver->ttys[idx];
1175 * tty_init_termios - helper for termios setup
1176 * @tty: the tty to set up
1178 * Initialise the termios structures for this tty. Thus runs under
1179 * the tty_mutex currently so we can be relaxed about ordering.
1182 int tty_init_termios(struct tty_struct *tty)
1184 struct ktermios *tp;
1185 int idx = tty->index;
1187 tp = tty->driver->termios[idx];
1189 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1192 memcpy(tp, &tty->driver->init_termios,
1193 sizeof(struct ktermios));
1194 tty->driver->termios[idx] = tp;
1197 tty->termios_locked = tp + 1;
1199 /* Compatibility until drivers always set this */
1200 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1201 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1204 EXPORT_SYMBOL_GPL(tty_init_termios);
1207 * tty_driver_install_tty() - install a tty entry in the driver
1208 * @driver: the driver for the tty
1211 * Install a tty object into the driver tables. The tty->index field
1212 * will be set by the time this is called. This method is responsible
1213 * for ensuring any need additional structures are allocated and
1216 * Locking: tty_mutex for now
1218 static int tty_driver_install_tty(struct tty_driver *driver,
1219 struct tty_struct *tty)
1221 int idx = tty->index;
1224 if (driver->ops->install) {
1225 ret = driver->ops->install(driver, tty);
1229 if (tty_init_termios(tty) == 0) {
1230 tty_driver_kref_get(driver);
1232 driver->ttys[idx] = tty;
1239 * tty_driver_remove_tty() - remove a tty from the driver tables
1240 * @driver: the driver for the tty
1241 * @idx: the minor number
1243 * Remvoe a tty object from the driver tables. The tty->index field
1244 * will be set by the time this is called.
1246 * Locking: tty_mutex for now
1248 static void tty_driver_remove_tty(struct tty_driver *driver,
1249 struct tty_struct *tty)
1251 if (driver->ops->remove)
1252 driver->ops->remove(driver, tty);
1254 driver->ttys[tty->index] = NULL;
1258 * tty_reopen() - fast re-open of an open tty
1259 * @tty - the tty to open
1261 * Return 0 on success, -errno on error.
1263 * Locking: tty_mutex must be held from the time the tty was found
1264 * till this open completes.
1266 static int tty_reopen(struct tty_struct *tty)
1268 struct tty_driver *driver = tty->driver;
1270 if (test_bit(TTY_CLOSING, &tty->flags))
1273 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1274 driver->subtype == PTY_TYPE_MASTER) {
1276 * special case for PTY masters: only one open permitted,
1277 * and the slave side open count is incremented as well.
1285 tty->driver = driver; /* N.B. why do this every time?? */
1287 mutex_lock(&tty->ldisc_mutex);
1288 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1289 mutex_unlock(&tty->ldisc_mutex);
1295 * tty_init_dev - initialise a tty device
1296 * @driver: tty driver we are opening a device on
1297 * @idx: device index
1298 * @ret_tty: returned tty structure
1299 * @first_ok: ok to open a new device (used by ptmx)
1301 * Prepare a tty device. This may not be a "new" clean device but
1302 * could also be an active device. The pty drivers require special
1303 * handling because of this.
1306 * The function is called under the tty_mutex, which
1307 * protects us from the tty struct or driver itself going away.
1309 * On exit the tty device has the line discipline attached and
1310 * a reference count of 1. If a pair was created for pty/tty use
1311 * and the other was a pty master then it too has a reference count of 1.
1313 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1314 * failed open. The new code protects the open with a mutex, so it's
1315 * really quite straightforward. The mutex locking can probably be
1316 * relaxed for the (most common) case of reopening a tty.
1319 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1322 struct tty_struct *tty;
1325 /* Check if pty master is being opened multiple times */
1326 if (driver->subtype == PTY_TYPE_MASTER &&
1327 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1328 return ERR_PTR(-EIO);
1332 * First time open is complex, especially for PTY devices.
1333 * This code guarantees that either everything succeeds and the
1334 * TTY is ready for operation, or else the table slots are vacated
1335 * and the allocated memory released. (Except that the termios
1336 * and locked termios may be retained.)
1339 if (!try_module_get(driver->owner))
1340 return ERR_PTR(-ENODEV);
1342 tty = alloc_tty_struct();
1345 initialize_tty_struct(tty, driver, idx);
1347 retval = tty_driver_install_tty(driver, tty);
1349 free_tty_struct(tty);
1350 module_put(driver->owner);
1351 return ERR_PTR(retval);
1355 * Structures all installed ... call the ldisc open routines.
1356 * If we fail here just call release_tty to clean up. No need
1357 * to decrement the use counts, as release_tty doesn't care.
1359 retval = tty_ldisc_setup(tty, tty->link);
1361 goto release_mem_out;
1365 module_put(driver->owner);
1366 return ERR_PTR(-ENOMEM);
1368 /* call the tty release_tty routine to clean out this slot */
1370 if (printk_ratelimit())
1371 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1372 "clearing slot %d\n", idx);
1373 release_tty(tty, idx);
1374 return ERR_PTR(retval);
1377 void tty_free_termios(struct tty_struct *tty)
1379 struct ktermios *tp;
1380 int idx = tty->index;
1381 /* Kill this flag and push into drivers for locking etc */
1382 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1383 /* FIXME: Locking on ->termios array */
1385 tty->driver->termios[idx] = NULL;
1389 EXPORT_SYMBOL(tty_free_termios);
1391 void tty_shutdown(struct tty_struct *tty)
1393 tty_driver_remove_tty(tty->driver, tty);
1394 tty_free_termios(tty);
1396 EXPORT_SYMBOL(tty_shutdown);
1399 * release_one_tty - release tty structure memory
1400 * @kref: kref of tty we are obliterating
1402 * Releases memory associated with a tty structure, and clears out the
1403 * driver table slots. This function is called when a device is no longer
1404 * in use. It also gets called when setup of a device fails.
1407 * tty_mutex - sometimes only
1408 * takes the file list lock internally when working on the list
1409 * of ttys that the driver keeps.
1411 * This method gets called from a work queue so that the driver private
1412 * cleanup ops can sleep (needed for USB at least)
1414 static void release_one_tty(struct work_struct *work)
1416 struct tty_struct *tty =
1417 container_of(work, struct tty_struct, hangup_work);
1418 struct tty_driver *driver = tty->driver;
1420 if (tty->ops->cleanup)
1421 tty->ops->cleanup(tty);
1424 tty_driver_kref_put(driver);
1425 module_put(driver->owner);
1428 list_del_init(&tty->tty_files);
1432 put_pid(tty->session);
1433 free_tty_struct(tty);
1436 static void queue_release_one_tty(struct kref *kref)
1438 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1440 if (tty->ops->shutdown)
1441 tty->ops->shutdown(tty);
1445 /* The hangup queue is now free so we can reuse it rather than
1446 waste a chunk of memory for each port */
1447 INIT_WORK(&tty->hangup_work, release_one_tty);
1448 schedule_work(&tty->hangup_work);
1452 * tty_kref_put - release a tty kref
1455 * Release a reference to a tty device and if need be let the kref
1456 * layer destruct the object for us
1459 void tty_kref_put(struct tty_struct *tty)
1462 kref_put(&tty->kref, queue_release_one_tty);
1464 EXPORT_SYMBOL(tty_kref_put);
1467 * release_tty - release tty structure memory
1469 * Release both @tty and a possible linked partner (think pty pair),
1470 * and decrement the refcount of the backing module.
1473 * tty_mutex - sometimes only
1474 * takes the file list lock internally when working on the list
1475 * of ttys that the driver keeps.
1476 * FIXME: should we require tty_mutex is held here ??
1479 static void release_tty(struct tty_struct *tty, int idx)
1481 /* This should always be true but check for the moment */
1482 WARN_ON(tty->index != idx);
1485 tty_kref_put(tty->link);
1490 * tty_release - vfs callback for close
1491 * @inode: inode of tty
1492 * @filp: file pointer for handle to tty
1494 * Called the last time each file handle is closed that references
1495 * this tty. There may however be several such references.
1498 * Takes bkl. See tty_release_dev
1500 * Even releasing the tty structures is a tricky business.. We have
1501 * to be very careful that the structures are all released at the
1502 * same time, as interrupts might otherwise get the wrong pointers.
1504 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1505 * lead to double frees or releasing memory still in use.
1508 int tty_release(struct inode *inode, struct file *filp)
1510 struct tty_struct *tty, *o_tty;
1511 int pty_master, tty_closing, o_tty_closing, do_sleep;
1516 tty = filp->private_data;
1517 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1521 check_tty_count(tty, "tty_release_dev");
1523 __tty_fasync(-1, filp, 0);
1526 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1527 tty->driver->subtype == PTY_TYPE_MASTER);
1528 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1531 #ifdef TTY_PARANOIA_CHECK
1532 if (idx < 0 || idx >= tty->driver->num) {
1533 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1534 "free (%s)\n", tty->name);
1539 if (tty != tty->driver->ttys[idx]) {
1541 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1542 "for (%s)\n", idx, tty->name);
1545 if (tty->termios != tty->driver->termios[idx]) {
1547 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1555 #ifdef TTY_DEBUG_HANGUP
1556 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1557 tty_name(tty, buf), tty->count);
1560 #ifdef TTY_PARANOIA_CHECK
1561 if (tty->driver->other &&
1562 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1563 if (o_tty != tty->driver->other->ttys[idx]) {
1565 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1566 "not o_tty for (%s)\n",
1570 if (o_tty->termios != tty->driver->other->termios[idx]) {
1572 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1573 "not o_termios for (%s)\n",
1577 if (o_tty->link != tty) {
1579 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1584 if (tty->ops->close)
1585 tty->ops->close(tty, filp);
1589 * Sanity check: if tty->count is going to zero, there shouldn't be
1590 * any waiters on tty->read_wait or tty->write_wait. We test the
1591 * wait queues and kick everyone out _before_ actually starting to
1592 * close. This ensures that we won't block while releasing the tty
1595 * The test for the o_tty closing is necessary, since the master and
1596 * slave sides may close in any order. If the slave side closes out
1597 * first, its count will be one, since the master side holds an open.
1598 * Thus this test wouldn't be triggered at the time the slave closes,
1601 * Note that it's possible for the tty to be opened again while we're
1602 * flushing out waiters. By recalculating the closing flags before
1603 * each iteration we avoid any problems.
1606 /* Guard against races with tty->count changes elsewhere and
1607 opens on /dev/tty */
1609 mutex_lock(&tty_mutex);
1611 tty_closing = tty->count <= 1;
1612 o_tty_closing = o_tty &&
1613 (o_tty->count <= (pty_master ? 1 : 0));
1617 if (waitqueue_active(&tty->read_wait)) {
1618 wake_up_poll(&tty->read_wait, POLLIN);
1621 if (waitqueue_active(&tty->write_wait)) {
1622 wake_up_poll(&tty->write_wait, POLLOUT);
1626 if (o_tty_closing) {
1627 if (waitqueue_active(&o_tty->read_wait)) {
1628 wake_up_poll(&o_tty->read_wait, POLLIN);
1631 if (waitqueue_active(&o_tty->write_wait)) {
1632 wake_up_poll(&o_tty->write_wait, POLLOUT);
1639 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1640 "active!\n", tty_name(tty, buf));
1642 mutex_unlock(&tty_mutex);
1647 * The closing flags are now consistent with the open counts on
1648 * both sides, and we've completed the last operation that could
1649 * block, so it's safe to proceed with closing.
1652 if (--o_tty->count < 0) {
1653 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1655 o_tty->count, tty_name(o_tty, buf));
1659 if (--tty->count < 0) {
1660 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1661 tty->count, tty_name(tty, buf));
1666 * We've decremented tty->count, so we need to remove this file
1667 * descriptor off the tty->tty_files list; this serves two
1669 * - check_tty_count sees the correct number of file descriptors
1670 * associated with this tty.
1671 * - do_tty_hangup no longer sees this file descriptor as
1672 * something that needs to be handled for hangups.
1675 filp->private_data = NULL;
1678 * Perform some housekeeping before deciding whether to return.
1680 * Set the TTY_CLOSING flag if this was the last open. In the
1681 * case of a pty we may have to wait around for the other side
1682 * to close, and TTY_CLOSING makes sure we can't be reopened.
1685 set_bit(TTY_CLOSING, &tty->flags);
1687 set_bit(TTY_CLOSING, &o_tty->flags);
1690 * If _either_ side is closing, make sure there aren't any
1691 * processes that still think tty or o_tty is their controlling
1694 if (tty_closing || o_tty_closing) {
1695 read_lock(&tasklist_lock);
1696 session_clear_tty(tty->session);
1698 session_clear_tty(o_tty->session);
1699 read_unlock(&tasklist_lock);
1702 mutex_unlock(&tty_mutex);
1704 /* check whether both sides are closing ... */
1705 if (!tty_closing || (o_tty && !o_tty_closing)) {
1710 #ifdef TTY_DEBUG_HANGUP
1711 printk(KERN_DEBUG "freeing tty structure...");
1714 * Ask the line discipline code to release its structures
1716 tty_ldisc_release(tty, o_tty);
1718 * The release_tty function takes care of the details of clearing
1719 * the slots and preserving the termios structure.
1721 release_tty(tty, idx);
1723 /* Make this pty number available for reallocation */
1725 devpts_kill_index(inode, idx);
1731 * tty_open - open a tty device
1732 * @inode: inode of device file
1733 * @filp: file pointer to tty
1735 * tty_open and tty_release keep up the tty count that contains the
1736 * number of opens done on a tty. We cannot use the inode-count, as
1737 * different inodes might point to the same tty.
1739 * Open-counting is needed for pty masters, as well as for keeping
1740 * track of serial lines: DTR is dropped when the last close happens.
1741 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1743 * The termios state of a pty is reset on first open so that
1744 * settings don't persist across reuse.
1746 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1747 * tty->count should protect the rest.
1748 * ->siglock protects ->signal/->sighand
1751 static int tty_open(struct inode *inode, struct file *filp)
1753 struct tty_struct *tty = NULL;
1755 struct tty_driver *driver;
1757 dev_t device = inode->i_rdev;
1758 unsigned saved_flags = filp->f_flags;
1760 nonseekable_open(inode, filp);
1763 noctty = filp->f_flags & O_NOCTTY;
1767 mutex_lock(&tty_mutex);
1770 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1771 tty = get_current_tty();
1774 mutex_unlock(&tty_mutex);
1777 driver = tty_driver_kref_get(tty->driver);
1779 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1781 /* FIXME: Should we take a driver reference ? */
1786 if (device == MKDEV(TTY_MAJOR, 0)) {
1787 extern struct tty_driver *console_driver;
1788 driver = tty_driver_kref_get(console_driver);
1794 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1795 struct tty_driver *console_driver = console_device(&index);
1796 if (console_driver) {
1797 driver = tty_driver_kref_get(console_driver);
1799 /* Don't let /dev/console block */
1800 filp->f_flags |= O_NONBLOCK;
1806 mutex_unlock(&tty_mutex);
1810 driver = get_tty_driver(device, &index);
1813 mutex_unlock(&tty_mutex);
1818 /* check whether we're reopening an existing tty */
1819 tty = tty_driver_lookup_tty(driver, inode, index);
1823 mutex_unlock(&tty_mutex);
1824 return PTR_ERR(tty);
1829 retval = tty_reopen(tty);
1831 tty = ERR_PTR(retval);
1833 tty = tty_init_dev(driver, index, 0);
1835 mutex_unlock(&tty_mutex);
1836 tty_driver_kref_put(driver);
1839 return PTR_ERR(tty);
1842 filp->private_data = tty;
1843 file_move(filp, &tty->tty_files);
1844 check_tty_count(tty, "tty_open");
1845 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1846 tty->driver->subtype == PTY_TYPE_MASTER)
1848 #ifdef TTY_DEBUG_HANGUP
1849 printk(KERN_DEBUG "opening %s...", tty->name);
1853 retval = tty->ops->open(tty, filp);
1857 filp->f_flags = saved_flags;
1859 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1860 !capable(CAP_SYS_ADMIN))
1864 #ifdef TTY_DEBUG_HANGUP
1865 printk(KERN_DEBUG "error %d in opening %s...", retval,
1868 tty_unlock(); /* need to call tty_release without BTM */
1869 tty_release(inode, filp);
1870 if (retval != -ERESTARTSYS)
1873 if (signal_pending(current))
1878 * Need to reset f_op in case a hangup happened.
1881 if (filp->f_op == &hung_up_tty_fops)
1882 filp->f_op = &tty_fops;
1889 mutex_lock(&tty_mutex);
1891 spin_lock_irq(¤t->sighand->siglock);
1893 current->signal->leader &&
1894 !current->signal->tty &&
1895 tty->session == NULL)
1896 __proc_set_tty(current, tty);
1897 spin_unlock_irq(¤t->sighand->siglock);
1899 mutex_unlock(&tty_mutex);
1906 * tty_poll - check tty status
1907 * @filp: file being polled
1908 * @wait: poll wait structures to update
1910 * Call the line discipline polling method to obtain the poll
1911 * status of the device.
1913 * Locking: locks called line discipline but ldisc poll method
1914 * may be re-entered freely by other callers.
1917 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1919 struct tty_struct *tty;
1920 struct tty_ldisc *ld;
1923 tty = filp->private_data;
1924 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1927 ld = tty_ldisc_ref_wait(tty);
1929 ret = (ld->ops->poll)(tty, filp, wait);
1930 tty_ldisc_deref(ld);
1934 static int __tty_fasync(int fd, struct file *filp, int on)
1936 struct tty_struct *tty;
1937 unsigned long flags;
1940 tty = filp->private_data;
1941 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1944 retval = fasync_helper(fd, filp, on, &tty->fasync);
1951 if (!waitqueue_active(&tty->read_wait))
1952 tty->minimum_to_wake = 1;
1953 spin_lock_irqsave(&tty->ctrl_lock, flags);
1956 type = PIDTYPE_PGID;
1958 pid = task_pid(current);
1962 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1963 retval = __f_setown(filp, pid, type, 0);
1968 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
1969 tty->minimum_to_wake = N_TTY_BUF_SIZE;
1976 static int tty_fasync(int fd, struct file *filp, int on)
1980 retval = __tty_fasync(fd, filp, on);
1986 * tiocsti - fake input character
1987 * @tty: tty to fake input into
1988 * @p: pointer to character
1990 * Fake input to a tty device. Does the necessary locking and
1993 * FIXME: does not honour flow control ??
1996 * Called functions take tty_ldisc_lock
1997 * current->signal->tty check is safe without locks
1999 * FIXME: may race normal receive processing
2002 static int tiocsti(struct tty_struct *tty, char __user *p)
2005 struct tty_ldisc *ld;
2007 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2009 if (get_user(ch, p))
2011 tty_audit_tiocsti(tty, ch);
2012 ld = tty_ldisc_ref_wait(tty);
2013 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2014 tty_ldisc_deref(ld);
2019 * tiocgwinsz - implement window query ioctl
2021 * @arg: user buffer for result
2023 * Copies the kernel idea of the window size into the user buffer.
2025 * Locking: tty->termios_mutex is taken to ensure the winsize data
2029 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2033 mutex_lock(&tty->termios_mutex);
2034 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2035 mutex_unlock(&tty->termios_mutex);
2037 return err ? -EFAULT: 0;
2041 * tty_do_resize - resize event
2042 * @tty: tty being resized
2043 * @rows: rows (character)
2044 * @cols: cols (character)
2046 * Update the termios variables and send the necessary signals to
2047 * peform a terminal resize correctly
2050 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2053 unsigned long flags;
2056 mutex_lock(&tty->termios_mutex);
2057 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2059 /* Get the PID values and reference them so we can
2060 avoid holding the tty ctrl lock while sending signals */
2061 spin_lock_irqsave(&tty->ctrl_lock, flags);
2062 pgrp = get_pid(tty->pgrp);
2063 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2066 kill_pgrp(pgrp, SIGWINCH, 1);
2071 mutex_unlock(&tty->termios_mutex);
2076 * tiocswinsz - implement window size set ioctl
2077 * @tty; tty side of tty
2078 * @arg: user buffer for result
2080 * Copies the user idea of the window size to the kernel. Traditionally
2081 * this is just advisory information but for the Linux console it
2082 * actually has driver level meaning and triggers a VC resize.
2085 * Driver dependant. The default do_resize method takes the
2086 * tty termios mutex and ctrl_lock. The console takes its own lock
2087 * then calls into the default method.
2090 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2092 struct winsize tmp_ws;
2093 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2096 if (tty->ops->resize)
2097 return tty->ops->resize(tty, &tmp_ws);
2099 return tty_do_resize(tty, &tmp_ws);
2103 * tioccons - allow admin to move logical console
2104 * @file: the file to become console
2106 * Allow the adminstrator to move the redirected console device
2108 * Locking: uses redirect_lock to guard the redirect information
2111 static int tioccons(struct file *file)
2113 if (!capable(CAP_SYS_ADMIN))
2115 if (file->f_op->write == redirected_tty_write) {
2117 spin_lock(&redirect_lock);
2120 spin_unlock(&redirect_lock);
2125 spin_lock(&redirect_lock);
2127 spin_unlock(&redirect_lock);
2132 spin_unlock(&redirect_lock);
2137 * fionbio - non blocking ioctl
2138 * @file: file to set blocking value
2139 * @p: user parameter
2141 * Historical tty interfaces had a blocking control ioctl before
2142 * the generic functionality existed. This piece of history is preserved
2143 * in the expected tty API of posix OS's.
2145 * Locking: none, the open file handle ensures it won't go away.
2148 static int fionbio(struct file *file, int __user *p)
2152 if (get_user(nonblock, p))
2155 spin_lock(&file->f_lock);
2157 file->f_flags |= O_NONBLOCK;
2159 file->f_flags &= ~O_NONBLOCK;
2160 spin_unlock(&file->f_lock);
2165 * tiocsctty - set controlling tty
2166 * @tty: tty structure
2167 * @arg: user argument
2169 * This ioctl is used to manage job control. It permits a session
2170 * leader to set this tty as the controlling tty for the session.
2173 * Takes tty_mutex() to protect tty instance
2174 * Takes tasklist_lock internally to walk sessions
2175 * Takes ->siglock() when updating signal->tty
2178 static int tiocsctty(struct tty_struct *tty, int arg)
2181 if (current->signal->leader && (task_session(current) == tty->session))
2184 mutex_lock(&tty_mutex);
2186 * The process must be a session leader and
2187 * not have a controlling tty already.
2189 if (!current->signal->leader || current->signal->tty) {
2196 * This tty is already the controlling
2197 * tty for another session group!
2199 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2203 read_lock(&tasklist_lock);
2204 session_clear_tty(tty->session);
2205 read_unlock(&tasklist_lock);
2211 proc_set_tty(current, tty);
2213 mutex_unlock(&tty_mutex);
2218 * tty_get_pgrp - return a ref counted pgrp pid
2221 * Returns a refcounted instance of the pid struct for the process
2222 * group controlling the tty.
2225 struct pid *tty_get_pgrp(struct tty_struct *tty)
2227 unsigned long flags;
2230 spin_lock_irqsave(&tty->ctrl_lock, flags);
2231 pgrp = get_pid(tty->pgrp);
2232 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2236 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2239 * tiocgpgrp - get process group
2240 * @tty: tty passed by user
2241 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2244 * Obtain the process group of the tty. If there is no process group
2247 * Locking: none. Reference to current->signal->tty is safe.
2250 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2255 * (tty == real_tty) is a cheap way of
2256 * testing if the tty is NOT a master pty.
2258 if (tty == real_tty && current->signal->tty != real_tty)
2260 pid = tty_get_pgrp(real_tty);
2261 ret = put_user(pid_vnr(pid), p);
2267 * tiocspgrp - attempt to set process group
2268 * @tty: tty passed by user
2269 * @real_tty: tty side device matching tty passed by user
2272 * Set the process group of the tty to the session passed. Only
2273 * permitted where the tty session is our session.
2275 * Locking: RCU, ctrl lock
2278 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2282 int retval = tty_check_change(real_tty);
2283 unsigned long flags;
2289 if (!current->signal->tty ||
2290 (current->signal->tty != real_tty) ||
2291 (real_tty->session != task_session(current)))
2293 if (get_user(pgrp_nr, p))
2298 pgrp = find_vpid(pgrp_nr);
2303 if (session_of_pgrp(pgrp) != task_session(current))
2306 spin_lock_irqsave(&tty->ctrl_lock, flags);
2307 put_pid(real_tty->pgrp);
2308 real_tty->pgrp = get_pid(pgrp);
2309 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2316 * tiocgsid - get session id
2317 * @tty: tty passed by user
2318 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2319 * @p: pointer to returned session id
2321 * Obtain the session id of the tty. If there is no session
2324 * Locking: none. Reference to current->signal->tty is safe.
2327 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2330 * (tty == real_tty) is a cheap way of
2331 * testing if the tty is NOT a master pty.
2333 if (tty == real_tty && current->signal->tty != real_tty)
2335 if (!real_tty->session)
2337 return put_user(pid_vnr(real_tty->session), p);
2341 * tiocsetd - set line discipline
2343 * @p: pointer to user data
2345 * Set the line discipline according to user request.
2347 * Locking: see tty_set_ldisc, this function is just a helper
2350 static int tiocsetd(struct tty_struct *tty, int __user *p)
2355 if (get_user(ldisc, p))
2358 ret = tty_set_ldisc(tty, ldisc);
2364 * send_break - performed time break
2365 * @tty: device to break on
2366 * @duration: timeout in mS
2368 * Perform a timed break on hardware that lacks its own driver level
2369 * timed break functionality.
2372 * atomic_write_lock serializes
2376 static int send_break(struct tty_struct *tty, unsigned int duration)
2380 if (tty->ops->break_ctl == NULL)
2383 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2384 retval = tty->ops->break_ctl(tty, duration);
2386 /* Do the work ourselves */
2387 if (tty_write_lock(tty, 0) < 0)
2389 retval = tty->ops->break_ctl(tty, -1);
2392 if (!signal_pending(current))
2393 msleep_interruptible(duration);
2394 retval = tty->ops->break_ctl(tty, 0);
2396 tty_write_unlock(tty);
2397 if (signal_pending(current))
2404 * tty_tiocmget - get modem status
2406 * @file: user file pointer
2407 * @p: pointer to result
2409 * Obtain the modem status bits from the tty driver if the feature
2410 * is supported. Return -EINVAL if it is not available.
2412 * Locking: none (up to the driver)
2415 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2417 int retval = -EINVAL;
2419 if (tty->ops->tiocmget) {
2420 retval = tty->ops->tiocmget(tty, file);
2423 retval = put_user(retval, p);
2429 * tty_tiocmset - set modem status
2431 * @file: user file pointer
2432 * @cmd: command - clear bits, set bits or set all
2433 * @p: pointer to desired bits
2435 * Set the modem status bits from the tty driver if the feature
2436 * is supported. Return -EINVAL if it is not available.
2438 * Locking: none (up to the driver)
2441 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2445 unsigned int set, clear, val;
2447 if (tty->ops->tiocmset == NULL)
2450 retval = get_user(val, p);
2466 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2467 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2468 return tty->ops->tiocmset(tty, file, set, clear);
2471 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2473 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2474 tty->driver->subtype == PTY_TYPE_MASTER)
2478 EXPORT_SYMBOL(tty_pair_get_tty);
2480 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2482 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2483 tty->driver->subtype == PTY_TYPE_MASTER)
2487 EXPORT_SYMBOL(tty_pair_get_pty);
2490 * Split this up, as gcc can choke on it otherwise..
2492 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2494 struct tty_struct *tty, *real_tty;
2495 void __user *p = (void __user *)arg;
2497 struct tty_ldisc *ld;
2498 struct inode *inode = file->f_dentry->d_inode;
2500 tty = file->private_data;
2501 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2504 real_tty = tty_pair_get_tty(tty);
2507 * Factor out some common prep work
2515 retval = tty_check_change(tty);
2518 if (cmd != TIOCCBRK) {
2519 tty_wait_until_sent(tty, 0);
2520 if (signal_pending(current))
2531 return tiocsti(tty, p);
2533 return tiocgwinsz(real_tty, p);
2535 return tiocswinsz(real_tty, p);
2537 return real_tty != tty ? -EINVAL : tioccons(file);
2539 return fionbio(file, p);
2541 set_bit(TTY_EXCLUSIVE, &tty->flags);
2544 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2547 if (current->signal->tty != tty)
2552 return tiocsctty(tty, arg);
2554 return tiocgpgrp(tty, real_tty, p);
2556 return tiocspgrp(tty, real_tty, p);
2558 return tiocgsid(tty, real_tty, p);
2560 return put_user(tty->ldisc->ops->num, (int __user *)p);
2562 return tiocsetd(tty, p);
2566 case TIOCSBRK: /* Turn break on, unconditionally */
2567 if (tty->ops->break_ctl)
2568 return tty->ops->break_ctl(tty, -1);
2570 case TIOCCBRK: /* Turn break off, unconditionally */
2571 if (tty->ops->break_ctl)
2572 return tty->ops->break_ctl(tty, 0);
2574 case TCSBRK: /* SVID version: non-zero arg --> no break */
2575 /* non-zero arg means wait for all output data
2576 * to be sent (performed above) but don't send break.
2577 * This is used by the tcdrain() termios function.
2580 return send_break(tty, 250);
2582 case TCSBRKP: /* support for POSIX tcsendbreak() */
2583 return send_break(tty, arg ? arg*100 : 250);
2586 return tty_tiocmget(tty, file, p);
2590 return tty_tiocmset(tty, file, cmd, p);
2595 /* flush tty buffer and allow ldisc to process ioctl */
2596 tty_buffer_flush(tty);
2601 if (tty->ops->ioctl) {
2602 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2603 if (retval != -ENOIOCTLCMD)
2606 ld = tty_ldisc_ref_wait(tty);
2608 if (ld->ops->ioctl) {
2609 retval = ld->ops->ioctl(tty, file, cmd, arg);
2610 if (retval == -ENOIOCTLCMD)
2613 tty_ldisc_deref(ld);
2617 #ifdef CONFIG_COMPAT
2618 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2621 struct inode *inode = file->f_dentry->d_inode;
2622 struct tty_struct *tty = file->private_data;
2623 struct tty_ldisc *ld;
2624 int retval = -ENOIOCTLCMD;
2626 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2629 if (tty->ops->compat_ioctl) {
2630 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2631 if (retval != -ENOIOCTLCMD)
2635 ld = tty_ldisc_ref_wait(tty);
2636 if (ld->ops->compat_ioctl)
2637 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2638 tty_ldisc_deref(ld);
2645 * This implements the "Secure Attention Key" --- the idea is to
2646 * prevent trojan horses by killing all processes associated with this
2647 * tty when the user hits the "Secure Attention Key". Required for
2648 * super-paranoid applications --- see the Orange Book for more details.
2650 * This code could be nicer; ideally it should send a HUP, wait a few
2651 * seconds, then send a INT, and then a KILL signal. But you then
2652 * have to coordinate with the init process, since all processes associated
2653 * with the current tty must be dead before the new getty is allowed
2656 * Now, if it would be correct ;-/ The current code has a nasty hole -
2657 * it doesn't catch files in flight. We may send the descriptor to ourselves
2658 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2660 * Nasty bug: do_SAK is being called in interrupt context. This can
2661 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2663 void __do_SAK(struct tty_struct *tty)
2668 struct task_struct *g, *p;
2669 struct pid *session;
2672 struct fdtable *fdt;
2676 session = tty->session;
2678 tty_ldisc_flush(tty);
2680 tty_driver_flush_buffer(tty);
2682 read_lock(&tasklist_lock);
2683 /* Kill the entire session */
2684 do_each_pid_task(session, PIDTYPE_SID, p) {
2685 printk(KERN_NOTICE "SAK: killed process %d"
2686 " (%s): task_session(p)==tty->session\n",
2687 task_pid_nr(p), p->comm);
2688 send_sig(SIGKILL, p, 1);
2689 } while_each_pid_task(session, PIDTYPE_SID, p);
2690 /* Now kill any processes that happen to have the
2693 do_each_thread(g, p) {
2694 if (p->signal->tty == tty) {
2695 printk(KERN_NOTICE "SAK: killed process %d"
2696 " (%s): task_session(p)==tty->session\n",
2697 task_pid_nr(p), p->comm);
2698 send_sig(SIGKILL, p, 1);
2704 * We don't take a ref to the file, so we must
2705 * hold ->file_lock instead.
2707 spin_lock(&p->files->file_lock);
2708 fdt = files_fdtable(p->files);
2709 for (i = 0; i < fdt->max_fds; i++) {
2710 filp = fcheck_files(p->files, i);
2713 if (filp->f_op->read == tty_read &&
2714 filp->private_data == tty) {
2715 printk(KERN_NOTICE "SAK: killed process %d"
2716 " (%s): fd#%d opened to the tty\n",
2717 task_pid_nr(p), p->comm, i);
2718 force_sig(SIGKILL, p);
2722 spin_unlock(&p->files->file_lock);
2725 } while_each_thread(g, p);
2726 read_unlock(&tasklist_lock);
2730 static void do_SAK_work(struct work_struct *work)
2732 struct tty_struct *tty =
2733 container_of(work, struct tty_struct, SAK_work);
2738 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2739 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2740 * the values which we write to it will be identical to the values which it
2741 * already has. --akpm
2743 void do_SAK(struct tty_struct *tty)
2747 schedule_work(&tty->SAK_work);
2750 EXPORT_SYMBOL(do_SAK);
2753 * initialize_tty_struct
2754 * @tty: tty to initialize
2756 * This subroutine initializes a tty structure that has been newly
2759 * Locking: none - tty in question must not be exposed at this point
2762 void initialize_tty_struct(struct tty_struct *tty,
2763 struct tty_driver *driver, int idx)
2765 memset(tty, 0, sizeof(struct tty_struct));
2766 kref_init(&tty->kref);
2767 tty->magic = TTY_MAGIC;
2768 tty_ldisc_init(tty);
2769 tty->session = NULL;
2771 tty->overrun_time = jiffies;
2772 tty->buf.head = tty->buf.tail = NULL;
2773 tty_buffer_init(tty);
2774 mutex_init(&tty->termios_mutex);
2775 mutex_init(&tty->ldisc_mutex);
2776 init_waitqueue_head(&tty->write_wait);
2777 init_waitqueue_head(&tty->read_wait);
2778 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2779 mutex_init(&tty->atomic_read_lock);
2780 mutex_init(&tty->atomic_write_lock);
2781 mutex_init(&tty->output_lock);
2782 mutex_init(&tty->echo_lock);
2783 spin_lock_init(&tty->read_lock);
2784 spin_lock_init(&tty->ctrl_lock);
2785 INIT_LIST_HEAD(&tty->tty_files);
2786 INIT_WORK(&tty->SAK_work, do_SAK_work);
2788 tty->driver = driver;
2789 tty->ops = driver->ops;
2791 tty_line_name(driver, idx, tty->name);
2795 * tty_put_char - write one character to a tty
2799 * Write one byte to the tty using the provided put_char method
2800 * if present. Returns the number of characters successfully output.
2802 * Note: the specific put_char operation in the driver layer may go
2803 * away soon. Don't call it directly, use this method
2806 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2808 if (tty->ops->put_char)
2809 return tty->ops->put_char(tty, ch);
2810 return tty->ops->write(tty, &ch, 1);
2812 EXPORT_SYMBOL_GPL(tty_put_char);
2814 struct class *tty_class;
2817 * tty_register_device - register a tty device
2818 * @driver: the tty driver that describes the tty device
2819 * @index: the index in the tty driver for this tty device
2820 * @device: a struct device that is associated with this tty device.
2821 * This field is optional, if there is no known struct device
2822 * for this tty device it can be set to NULL safely.
2824 * Returns a pointer to the struct device for this tty device
2825 * (or ERR_PTR(-EFOO) on error).
2827 * This call is required to be made to register an individual tty device
2828 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2829 * that bit is not set, this function should not be called by a tty
2835 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2836 struct device *device)
2839 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2841 if (index >= driver->num) {
2842 printk(KERN_ERR "Attempt to register invalid tty line number "
2844 return ERR_PTR(-EINVAL);
2847 if (driver->type == TTY_DRIVER_TYPE_PTY)
2848 pty_line_name(driver, index, name);
2850 tty_line_name(driver, index, name);
2852 return device_create(tty_class, device, dev, NULL, name);
2854 EXPORT_SYMBOL(tty_register_device);
2857 * tty_unregister_device - unregister a tty device
2858 * @driver: the tty driver that describes the tty device
2859 * @index: the index in the tty driver for this tty device
2861 * If a tty device is registered with a call to tty_register_device() then
2862 * this function must be called when the tty device is gone.
2867 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2869 device_destroy(tty_class,
2870 MKDEV(driver->major, driver->minor_start) + index);
2872 EXPORT_SYMBOL(tty_unregister_device);
2874 struct tty_driver *alloc_tty_driver(int lines)
2876 struct tty_driver *driver;
2878 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2880 kref_init(&driver->kref);
2881 driver->magic = TTY_DRIVER_MAGIC;
2882 driver->num = lines;
2883 /* later we'll move allocation of tables here */
2887 EXPORT_SYMBOL(alloc_tty_driver);
2889 static void destruct_tty_driver(struct kref *kref)
2891 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2893 struct ktermios *tp;
2896 if (driver->flags & TTY_DRIVER_INSTALLED) {
2898 * Free the termios and termios_locked structures because
2899 * we don't want to get memory leaks when modular tty
2900 * drivers are removed from the kernel.
2902 for (i = 0; i < driver->num; i++) {
2903 tp = driver->termios[i];
2905 driver->termios[i] = NULL;
2908 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2909 tty_unregister_device(driver, i);
2912 proc_tty_unregister_driver(driver);
2913 driver->ttys = NULL;
2914 driver->termios = NULL;
2916 cdev_del(&driver->cdev);
2921 void tty_driver_kref_put(struct tty_driver *driver)
2923 kref_put(&driver->kref, destruct_tty_driver);
2925 EXPORT_SYMBOL(tty_driver_kref_put);
2927 void tty_set_operations(struct tty_driver *driver,
2928 const struct tty_operations *op)
2932 EXPORT_SYMBOL(tty_set_operations);
2934 void put_tty_driver(struct tty_driver *d)
2936 tty_driver_kref_put(d);
2938 EXPORT_SYMBOL(put_tty_driver);
2941 * Called by a tty driver to register itself.
2943 int tty_register_driver(struct tty_driver *driver)
2950 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2951 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2956 if (!driver->major) {
2957 error = alloc_chrdev_region(&dev, driver->minor_start,
2958 driver->num, driver->name);
2960 driver->major = MAJOR(dev);
2961 driver->minor_start = MINOR(dev);
2964 dev = MKDEV(driver->major, driver->minor_start);
2965 error = register_chrdev_region(dev, driver->num, driver->name);
2973 driver->ttys = (struct tty_struct **)p;
2974 driver->termios = (struct ktermios **)(p + driver->num);
2976 driver->ttys = NULL;
2977 driver->termios = NULL;
2980 cdev_init(&driver->cdev, &tty_fops);
2981 driver->cdev.owner = driver->owner;
2982 error = cdev_add(&driver->cdev, dev, driver->num);
2984 unregister_chrdev_region(dev, driver->num);
2985 driver->ttys = NULL;
2986 driver->termios = NULL;
2991 mutex_lock(&tty_mutex);
2992 list_add(&driver->tty_drivers, &tty_drivers);
2993 mutex_unlock(&tty_mutex);
2995 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
2996 for (i = 0; i < driver->num; i++)
2997 tty_register_device(driver, i, NULL);
2999 proc_tty_register_driver(driver);
3000 driver->flags |= TTY_DRIVER_INSTALLED;
3004 EXPORT_SYMBOL(tty_register_driver);
3007 * Called by a tty driver to unregister itself.
3009 int tty_unregister_driver(struct tty_driver *driver)
3013 if (driver->refcount)
3016 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3018 mutex_lock(&tty_mutex);
3019 list_del(&driver->tty_drivers);
3020 mutex_unlock(&tty_mutex);
3024 EXPORT_SYMBOL(tty_unregister_driver);
3026 dev_t tty_devnum(struct tty_struct *tty)
3028 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3030 EXPORT_SYMBOL(tty_devnum);
3032 void proc_clear_tty(struct task_struct *p)
3034 unsigned long flags;
3035 struct tty_struct *tty;
3036 spin_lock_irqsave(&p->sighand->siglock, flags);
3037 tty = p->signal->tty;
3038 p->signal->tty = NULL;
3039 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3043 /* Called under the sighand lock */
3045 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3048 unsigned long flags;
3049 /* We should not have a session or pgrp to put here but.... */
3050 spin_lock_irqsave(&tty->ctrl_lock, flags);
3051 put_pid(tty->session);
3053 tty->pgrp = get_pid(task_pgrp(tsk));
3054 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3055 tty->session = get_pid(task_session(tsk));
3056 if (tsk->signal->tty) {
3057 printk(KERN_DEBUG "tty not NULL!!\n");
3058 tty_kref_put(tsk->signal->tty);
3061 put_pid(tsk->signal->tty_old_pgrp);
3062 tsk->signal->tty = tty_kref_get(tty);
3063 tsk->signal->tty_old_pgrp = NULL;
3066 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3068 spin_lock_irq(&tsk->sighand->siglock);
3069 __proc_set_tty(tsk, tty);
3070 spin_unlock_irq(&tsk->sighand->siglock);
3073 struct tty_struct *get_current_tty(void)
3075 struct tty_struct *tty;
3076 unsigned long flags;
3078 spin_lock_irqsave(¤t->sighand->siglock, flags);
3079 tty = tty_kref_get(current->signal->tty);
3080 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3083 EXPORT_SYMBOL_GPL(get_current_tty);
3085 void tty_default_fops(struct file_operations *fops)
3091 * Initialize the console device. This is called *early*, so
3092 * we can't necessarily depend on lots of kernel help here.
3093 * Just do some early initializations, and do the complex setup
3096 void __init console_init(void)
3100 /* Setup the default TTY line discipline. */
3104 * set up the console device so that later boot sequences can
3105 * inform about problems etc..
3107 call = __con_initcall_start;
3108 while (call < __con_initcall_end) {
3114 static char *tty_devnode(struct device *dev, mode_t *mode)
3118 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3119 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3124 static int __init tty_class_init(void)
3126 tty_class = class_create(THIS_MODULE, "tty");
3127 if (IS_ERR(tty_class))
3128 return PTR_ERR(tty_class);
3129 tty_class->devnode = tty_devnode;
3133 postcore_initcall(tty_class_init);
3135 /* 3/2004 jmc: why do these devices exist? */
3137 static struct cdev tty_cdev, console_cdev;
3140 * Ok, now we can initialize the rest of the tty devices and can count
3141 * on memory allocations, interrupts etc..
3143 int __init tty_init(void)
3145 cdev_init(&tty_cdev, &tty_fops);
3146 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3147 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3148 panic("Couldn't register /dev/tty driver\n");
3149 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3152 cdev_init(&console_cdev, &console_fops);
3153 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3154 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3155 panic("Couldn't register /dev/console driver\n");
3156 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3160 vty_init(&console_fops);