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 static int tty_release(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
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;
509 /* inuse_filps is protected by the single kernel lock */
512 spin_lock(&redirect_lock);
513 if (redirect && redirect->private_data == tty) {
517 spin_unlock(&redirect_lock);
519 check_tty_count(tty, "do_tty_hangup");
521 /* This breaks for file handles being sent over AF_UNIX sockets ? */
522 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
523 if (filp->f_op->write == redirected_tty_write)
525 if (filp->f_op->write != tty_write)
528 tty_fasync(-1, filp, 0); /* can't block */
529 filp->f_op = &hung_up_tty_fops;
533 tty_ldisc_hangup(tty);
535 read_lock(&tasklist_lock);
537 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
538 spin_lock_irq(&p->sighand->siglock);
539 if (p->signal->tty == tty) {
540 p->signal->tty = NULL;
541 /* We defer the dereferences outside fo
545 if (!p->signal->leader) {
546 spin_unlock_irq(&p->sighand->siglock);
549 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
550 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
551 put_pid(p->signal->tty_old_pgrp); /* A noop */
552 spin_lock_irqsave(&tty->ctrl_lock, flags);
554 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
555 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
556 spin_unlock_irq(&p->sighand->siglock);
557 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
559 read_unlock(&tasklist_lock);
561 spin_lock_irqsave(&tty->ctrl_lock, flags);
562 clear_bit(TTY_THROTTLED, &tty->flags);
563 clear_bit(TTY_PUSH, &tty->flags);
564 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
565 put_pid(tty->session);
569 tty->ctrl_status = 0;
570 set_bit(TTY_HUPPED, &tty->flags);
571 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
573 /* Account for the p->signal references we killed */
578 * If one of the devices matches a console pointer, we
579 * cannot just call hangup() because that will cause
580 * tty->count and state->count to go out of sync.
581 * So we just call close() the right number of times.
585 for (n = 0; n < closecount; n++)
586 tty->ops->close(tty, cons_filp);
587 } else if (tty->ops->hangup)
588 (tty->ops->hangup)(tty);
590 * We don't want to have driver/ldisc interactions beyond
591 * the ones we did here. The driver layer expects no
592 * calls after ->hangup() from the ldisc side. However we
593 * can't yet guarantee all that.
595 set_bit(TTY_HUPPED, &tty->flags);
596 tty_ldisc_enable(tty);
603 * tty_hangup - trigger a hangup event
604 * @tty: tty to hangup
606 * A carrier loss (virtual or otherwise) has occurred on this like
607 * schedule a hangup sequence to run after this event.
610 void tty_hangup(struct tty_struct *tty)
612 #ifdef TTY_DEBUG_HANGUP
614 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
616 schedule_work(&tty->hangup_work);
619 EXPORT_SYMBOL(tty_hangup);
622 * tty_vhangup - process vhangup
623 * @tty: tty to hangup
625 * The user has asked via system call for the terminal to be hung up.
626 * We do this synchronously so that when the syscall returns the process
627 * is complete. That guarantee is necessary for security reasons.
630 void tty_vhangup(struct tty_struct *tty)
632 #ifdef TTY_DEBUG_HANGUP
635 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
637 do_tty_hangup(&tty->hangup_work);
640 EXPORT_SYMBOL(tty_vhangup);
643 * tty_vhangup_self - process vhangup for own ctty
645 * Perform a vhangup on the current controlling tty
648 void tty_vhangup_self(void)
650 struct tty_struct *tty;
652 tty = get_current_tty();
660 * tty_hung_up_p - was tty hung up
661 * @filp: file pointer of tty
663 * Return true if the tty has been subject to a vhangup or a carrier
667 int tty_hung_up_p(struct file *filp)
669 return (filp->f_op == &hung_up_tty_fops);
672 EXPORT_SYMBOL(tty_hung_up_p);
674 static void session_clear_tty(struct pid *session)
676 struct task_struct *p;
677 do_each_pid_task(session, PIDTYPE_SID, p) {
679 } while_each_pid_task(session, PIDTYPE_SID, p);
683 * disassociate_ctty - disconnect controlling tty
684 * @on_exit: true if exiting so need to "hang up" the session
686 * This function is typically called only by the session leader, when
687 * it wants to disassociate itself from its controlling tty.
689 * It performs the following functions:
690 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
691 * (2) Clears the tty from being controlling the session
692 * (3) Clears the controlling tty for all processes in the
695 * The argument on_exit is set to 1 if called when a process is
696 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
699 * BKL is taken for hysterical raisins
700 * tty_mutex is taken to protect tty
701 * ->siglock is taken to protect ->signal/->sighand
702 * tasklist_lock is taken to walk process list for sessions
703 * ->siglock is taken to protect ->signal/->sighand
706 void disassociate_ctty(int on_exit)
708 struct tty_struct *tty;
709 struct pid *tty_pgrp = NULL;
712 tty = get_current_tty();
714 tty_pgrp = get_pid(tty->pgrp);
716 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
720 } else if (on_exit) {
721 struct pid *old_pgrp;
722 spin_lock_irq(¤t->sighand->siglock);
723 old_pgrp = current->signal->tty_old_pgrp;
724 current->signal->tty_old_pgrp = NULL;
725 spin_unlock_irq(¤t->sighand->siglock);
727 kill_pgrp(old_pgrp, SIGHUP, on_exit);
728 kill_pgrp(old_pgrp, SIGCONT, on_exit);
734 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
736 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
740 spin_lock_irq(¤t->sighand->siglock);
741 put_pid(current->signal->tty_old_pgrp);
742 current->signal->tty_old_pgrp = NULL;
743 spin_unlock_irq(¤t->sighand->siglock);
745 tty = get_current_tty();
748 spin_lock_irqsave(&tty->ctrl_lock, flags);
749 put_pid(tty->session);
753 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
756 #ifdef TTY_DEBUG_HANGUP
757 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
762 /* Now clear signal->tty under the lock */
763 read_lock(&tasklist_lock);
764 session_clear_tty(task_session(current));
765 read_unlock(&tasklist_lock);
770 * no_tty - Ensure the current process does not have a controlling tty
774 struct task_struct *tsk = current;
776 if (tsk->signal->leader)
777 disassociate_ctty(0);
784 * stop_tty - propagate flow control
787 * Perform flow control to the driver. For PTY/TTY pairs we
788 * must also propagate the TIOCKPKT status. May be called
789 * on an already stopped device and will not re-call the driver
792 * This functionality is used by both the line disciplines for
793 * halting incoming flow and by the driver. It may therefore be
794 * called from any context, may be under the tty atomic_write_lock
798 * Uses the tty control lock internally
801 void stop_tty(struct tty_struct *tty)
804 spin_lock_irqsave(&tty->ctrl_lock, flags);
806 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
810 if (tty->link && tty->link->packet) {
811 tty->ctrl_status &= ~TIOCPKT_START;
812 tty->ctrl_status |= TIOCPKT_STOP;
813 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
815 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
817 (tty->ops->stop)(tty);
820 EXPORT_SYMBOL(stop_tty);
823 * start_tty - propagate flow control
826 * Start a tty that has been stopped if at all possible. Perform
827 * any necessary wakeups and propagate the TIOCPKT status. If this
828 * is the tty was previous stopped and is being started then the
829 * driver start method is invoked and the line discipline woken.
835 void start_tty(struct tty_struct *tty)
838 spin_lock_irqsave(&tty->ctrl_lock, flags);
839 if (!tty->stopped || tty->flow_stopped) {
840 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
844 if (tty->link && tty->link->packet) {
845 tty->ctrl_status &= ~TIOCPKT_STOP;
846 tty->ctrl_status |= TIOCPKT_START;
847 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
849 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
851 (tty->ops->start)(tty);
852 /* If we have a running line discipline it may need kicking */
856 EXPORT_SYMBOL(start_tty);
859 * tty_read - read method for tty device files
860 * @file: pointer to tty file
862 * @count: size of user buffer
865 * Perform the read system call function on this terminal device. Checks
866 * for hung up devices before calling the line discipline method.
869 * Locks the line discipline internally while needed. Multiple
870 * read calls may be outstanding in parallel.
873 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
877 struct tty_struct *tty;
879 struct tty_ldisc *ld;
881 tty = (struct tty_struct *)file->private_data;
882 inode = file->f_path.dentry->d_inode;
883 if (tty_paranoia_check(tty, inode, "tty_read"))
885 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
888 /* We want to wait for the line discipline to sort out in this
890 ld = tty_ldisc_ref_wait(tty);
892 i = (ld->ops->read)(tty, file, buf, count);
897 inode->i_atime = current_fs_time(inode->i_sb);
901 void tty_write_unlock(struct tty_struct *tty)
903 mutex_unlock(&tty->atomic_write_lock);
904 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
907 int tty_write_lock(struct tty_struct *tty, int ndelay)
909 if (!mutex_trylock(&tty->atomic_write_lock)) {
912 if (mutex_lock_interruptible(&tty->atomic_write_lock))
919 * Split writes up in sane blocksizes to avoid
920 * denial-of-service type attacks
922 static inline ssize_t do_tty_write(
923 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
924 struct tty_struct *tty,
926 const char __user *buf,
929 ssize_t ret, written = 0;
932 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
937 * We chunk up writes into a temporary buffer. This
938 * simplifies low-level drivers immensely, since they
939 * don't have locking issues and user mode accesses.
941 * But if TTY_NO_WRITE_SPLIT is set, we should use a
944 * The default chunk-size is 2kB, because the NTTY
945 * layer has problems with bigger chunks. It will
946 * claim to be able to handle more characters than
949 * FIXME: This can probably go away now except that 64K chunks
950 * are too likely to fail unless switched to vmalloc...
953 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
958 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
959 if (tty->write_cnt < chunk) {
960 unsigned char *buf_chunk;
965 buf_chunk = kmalloc(chunk, GFP_KERNEL);
970 kfree(tty->write_buf);
971 tty->write_cnt = chunk;
972 tty->write_buf = buf_chunk;
975 /* Do the write .. */
981 if (copy_from_user(tty->write_buf, buf, size))
983 ret = write(tty, file, tty->write_buf, size);
992 if (signal_pending(current))
997 struct inode *inode = file->f_path.dentry->d_inode;
998 inode->i_mtime = current_fs_time(inode->i_sb);
1002 tty_write_unlock(tty);
1007 * tty_write_message - write a message to a certain tty, not just the console.
1008 * @tty: the destination tty_struct
1009 * @msg: the message to write
1011 * This is used for messages that need to be redirected to a specific tty.
1012 * We don't put it into the syslog queue right now maybe in the future if
1015 * We must still hold the BKL and test the CLOSING flag for the moment.
1018 void tty_write_message(struct tty_struct *tty, char *msg)
1022 mutex_lock(&tty->atomic_write_lock);
1023 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
1024 tty->ops->write(tty, msg, strlen(msg));
1025 tty_write_unlock(tty);
1033 * tty_write - write method for tty device file
1034 * @file: tty file pointer
1035 * @buf: user data to write
1036 * @count: bytes to write
1039 * Write data to a tty device via the line discipline.
1042 * Locks the line discipline as required
1043 * Writes to the tty driver are serialized by the atomic_write_lock
1044 * and are then processed in chunks to the device. The line discipline
1045 * write method will not be invoked in parallel for each device.
1048 static ssize_t tty_write(struct file *file, const char __user *buf,
1049 size_t count, loff_t *ppos)
1051 struct tty_struct *tty;
1052 struct inode *inode = file->f_path.dentry->d_inode;
1054 struct tty_ldisc *ld;
1056 tty = (struct tty_struct *)file->private_data;
1057 if (tty_paranoia_check(tty, inode, "tty_write"))
1059 if (!tty || !tty->ops->write ||
1060 (test_bit(TTY_IO_ERROR, &tty->flags)))
1062 /* Short term debug to catch buggy drivers */
1063 if (tty->ops->write_room == NULL)
1064 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1066 ld = tty_ldisc_ref_wait(tty);
1067 if (!ld->ops->write)
1070 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1071 tty_ldisc_deref(ld);
1075 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1076 size_t count, loff_t *ppos)
1078 struct file *p = NULL;
1080 spin_lock(&redirect_lock);
1085 spin_unlock(&redirect_lock);
1089 res = vfs_write(p, buf, count, &p->f_pos);
1093 return tty_write(file, buf, count, ppos);
1096 static char ptychar[] = "pqrstuvwxyzabcde";
1099 * pty_line_name - generate name for a pty
1100 * @driver: the tty driver in use
1101 * @index: the minor number
1102 * @p: output buffer of at least 6 bytes
1104 * Generate a name from a driver reference and write it to the output
1109 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1111 int i = index + driver->name_base;
1112 /* ->name is initialized to "ttyp", but "tty" is expected */
1113 sprintf(p, "%s%c%x",
1114 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1115 ptychar[i >> 4 & 0xf], i & 0xf);
1119 * tty_line_name - generate name for a tty
1120 * @driver: the tty driver in use
1121 * @index: the minor number
1122 * @p: output buffer of at least 7 bytes
1124 * Generate a name from a driver reference and write it to the output
1129 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1131 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1135 * tty_driver_lookup_tty() - find an existing tty, if any
1136 * @driver: the driver for the tty
1137 * @idx: the minor number
1139 * Return the tty, if found or ERR_PTR() otherwise.
1141 * Locking: tty_mutex must be held. If tty is found, the mutex must
1142 * be held until the 'fast-open' is also done. Will change once we
1143 * have refcounting in the driver and per driver locking
1145 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1146 struct inode *inode, int idx)
1148 struct tty_struct *tty;
1150 if (driver->ops->lookup)
1151 return driver->ops->lookup(driver, inode, idx);
1153 tty = driver->ttys[idx];
1158 * tty_init_termios - helper for termios setup
1159 * @tty: the tty to set up
1161 * Initialise the termios structures for this tty. Thus runs under
1162 * the tty_mutex currently so we can be relaxed about ordering.
1165 int tty_init_termios(struct tty_struct *tty)
1167 struct ktermios *tp;
1168 int idx = tty->index;
1170 tp = tty->driver->termios[idx];
1172 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1175 memcpy(tp, &tty->driver->init_termios,
1176 sizeof(struct ktermios));
1177 tty->driver->termios[idx] = tp;
1180 tty->termios_locked = tp + 1;
1182 /* Compatibility until drivers always set this */
1183 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1184 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1187 EXPORT_SYMBOL_GPL(tty_init_termios);
1190 * tty_driver_install_tty() - install a tty entry in the driver
1191 * @driver: the driver for the tty
1194 * Install a tty object into the driver tables. The tty->index field
1195 * will be set by the time this is called. This method is responsible
1196 * for ensuring any need additional structures are allocated and
1199 * Locking: tty_mutex for now
1201 static int tty_driver_install_tty(struct tty_driver *driver,
1202 struct tty_struct *tty)
1204 int idx = tty->index;
1206 if (driver->ops->install)
1207 return driver->ops->install(driver, tty);
1209 if (tty_init_termios(tty) == 0) {
1210 tty_driver_kref_get(driver);
1212 driver->ttys[idx] = tty;
1219 * tty_driver_remove_tty() - remove a tty from the driver tables
1220 * @driver: the driver for the tty
1221 * @idx: the minor number
1223 * Remvoe a tty object from the driver tables. The tty->index field
1224 * will be set by the time this is called.
1226 * Locking: tty_mutex for now
1228 static void tty_driver_remove_tty(struct tty_driver *driver,
1229 struct tty_struct *tty)
1231 if (driver->ops->remove)
1232 driver->ops->remove(driver, tty);
1234 driver->ttys[tty->index] = NULL;
1238 * tty_reopen() - fast re-open of an open tty
1239 * @tty - the tty to open
1241 * Return 0 on success, -errno on error.
1243 * Locking: tty_mutex must be held from the time the tty was found
1244 * till this open completes.
1246 static int tty_reopen(struct tty_struct *tty)
1248 struct tty_driver *driver = tty->driver;
1250 if (test_bit(TTY_CLOSING, &tty->flags))
1253 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1254 driver->subtype == PTY_TYPE_MASTER) {
1256 * special case for PTY masters: only one open permitted,
1257 * and the slave side open count is incremented as well.
1265 tty->driver = driver; /* N.B. why do this every time?? */
1267 mutex_lock(&tty->ldisc_mutex);
1268 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1269 mutex_unlock(&tty->ldisc_mutex);
1275 * tty_init_dev - initialise a tty device
1276 * @driver: tty driver we are opening a device on
1277 * @idx: device index
1278 * @ret_tty: returned tty structure
1279 * @first_ok: ok to open a new device (used by ptmx)
1281 * Prepare a tty device. This may not be a "new" clean device but
1282 * could also be an active device. The pty drivers require special
1283 * handling because of this.
1286 * The function is called under the tty_mutex, which
1287 * protects us from the tty struct or driver itself going away.
1289 * On exit the tty device has the line discipline attached and
1290 * a reference count of 1. If a pair was created for pty/tty use
1291 * and the other was a pty master then it too has a reference count of 1.
1293 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1294 * failed open. The new code protects the open with a mutex, so it's
1295 * really quite straightforward. The mutex locking can probably be
1296 * relaxed for the (most common) case of reopening a tty.
1299 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1302 struct tty_struct *tty;
1305 /* Check if pty master is being opened multiple times */
1306 if (driver->subtype == PTY_TYPE_MASTER &&
1307 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok)
1308 return ERR_PTR(-EIO);
1311 * First time open is complex, especially for PTY devices.
1312 * This code guarantees that either everything succeeds and the
1313 * TTY is ready for operation, or else the table slots are vacated
1314 * and the allocated memory released. (Except that the termios
1315 * and locked termios may be retained.)
1318 if (!try_module_get(driver->owner))
1319 return ERR_PTR(-ENODEV);
1321 tty = alloc_tty_struct();
1324 initialize_tty_struct(tty, driver, idx);
1326 retval = tty_driver_install_tty(driver, tty);
1328 free_tty_struct(tty);
1329 module_put(driver->owner);
1330 return ERR_PTR(retval);
1334 * Structures all installed ... call the ldisc open routines.
1335 * If we fail here just call release_tty to clean up. No need
1336 * to decrement the use counts, as release_tty doesn't care.
1339 retval = tty_ldisc_setup(tty, tty->link);
1341 goto release_mem_out;
1345 module_put(driver->owner);
1346 return ERR_PTR(-ENOMEM);
1348 /* call the tty release_tty routine to clean out this slot */
1350 if (printk_ratelimit())
1351 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1352 "clearing slot %d\n", idx);
1353 release_tty(tty, idx);
1354 return ERR_PTR(retval);
1357 void tty_free_termios(struct tty_struct *tty)
1359 struct ktermios *tp;
1360 int idx = tty->index;
1361 /* Kill this flag and push into drivers for locking etc */
1362 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1363 /* FIXME: Locking on ->termios array */
1365 tty->driver->termios[idx] = NULL;
1369 EXPORT_SYMBOL(tty_free_termios);
1371 void tty_shutdown(struct tty_struct *tty)
1373 tty_driver_remove_tty(tty->driver, tty);
1374 tty_free_termios(tty);
1376 EXPORT_SYMBOL(tty_shutdown);
1379 * release_one_tty - release tty structure memory
1380 * @kref: kref of tty we are obliterating
1382 * Releases memory associated with a tty structure, and clears out the
1383 * driver table slots. This function is called when a device is no longer
1384 * in use. It also gets called when setup of a device fails.
1387 * tty_mutex - sometimes only
1388 * takes the file list lock internally when working on the list
1389 * of ttys that the driver keeps.
1391 * This method gets called from a work queue so that the driver private
1392 * cleanup ops can sleep (needed for USB at least)
1394 static void release_one_tty(struct work_struct *work)
1396 struct tty_struct *tty =
1397 container_of(work, struct tty_struct, hangup_work);
1398 struct tty_driver *driver = tty->driver;
1400 if (tty->ops->cleanup)
1401 tty->ops->cleanup(tty);
1404 tty_driver_kref_put(driver);
1405 module_put(driver->owner);
1408 list_del_init(&tty->tty_files);
1411 free_tty_struct(tty);
1414 static void queue_release_one_tty(struct kref *kref)
1416 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1418 if (tty->ops->shutdown)
1419 tty->ops->shutdown(tty);
1423 /* The hangup queue is now free so we can reuse it rather than
1424 waste a chunk of memory for each port */
1425 INIT_WORK(&tty->hangup_work, release_one_tty);
1426 schedule_work(&tty->hangup_work);
1430 * tty_kref_put - release a tty kref
1433 * Release a reference to a tty device and if need be let the kref
1434 * layer destruct the object for us
1437 void tty_kref_put(struct tty_struct *tty)
1440 kref_put(&tty->kref, queue_release_one_tty);
1442 EXPORT_SYMBOL(tty_kref_put);
1445 * release_tty - release tty structure memory
1447 * Release both @tty and a possible linked partner (think pty pair),
1448 * and decrement the refcount of the backing module.
1451 * tty_mutex - sometimes only
1452 * takes the file list lock internally when working on the list
1453 * of ttys that the driver keeps.
1454 * FIXME: should we require tty_mutex is held here ??
1457 static void release_tty(struct tty_struct *tty, int idx)
1459 /* This should always be true but check for the moment */
1460 WARN_ON(tty->index != idx);
1463 tty_kref_put(tty->link);
1468 * Even releasing the tty structures is a tricky business.. We have
1469 * to be very careful that the structures are all released at the
1470 * same time, as interrupts might otherwise get the wrong pointers.
1472 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1473 * lead to double frees or releasing memory still in use.
1475 void tty_release_dev(struct file *filp)
1477 struct tty_struct *tty, *o_tty;
1478 int pty_master, tty_closing, o_tty_closing, do_sleep;
1482 struct inode *inode;
1484 inode = filp->f_path.dentry->d_inode;
1485 tty = (struct tty_struct *)filp->private_data;
1486 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1489 check_tty_count(tty, "tty_release_dev");
1491 tty_fasync(-1, filp, 0);
1494 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1495 tty->driver->subtype == PTY_TYPE_MASTER);
1496 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1499 #ifdef TTY_PARANOIA_CHECK
1500 if (idx < 0 || idx >= tty->driver->num) {
1501 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1502 "free (%s)\n", tty->name);
1506 if (tty != tty->driver->ttys[idx]) {
1507 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1508 "for (%s)\n", idx, tty->name);
1511 if (tty->termios != tty->driver->termios[idx]) {
1512 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1520 #ifdef TTY_DEBUG_HANGUP
1521 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1522 tty_name(tty, buf), tty->count);
1525 #ifdef TTY_PARANOIA_CHECK
1526 if (tty->driver->other &&
1527 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1528 if (o_tty != tty->driver->other->ttys[idx]) {
1529 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1530 "not o_tty for (%s)\n",
1534 if (o_tty->termios != tty->driver->other->termios[idx]) {
1535 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1536 "not o_termios for (%s)\n",
1540 if (o_tty->link != tty) {
1541 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1546 if (tty->ops->close)
1547 tty->ops->close(tty, filp);
1550 * Sanity check: if tty->count is going to zero, there shouldn't be
1551 * any waiters on tty->read_wait or tty->write_wait. We test the
1552 * wait queues and kick everyone out _before_ actually starting to
1553 * close. This ensures that we won't block while releasing the tty
1556 * The test for the o_tty closing is necessary, since the master and
1557 * slave sides may close in any order. If the slave side closes out
1558 * first, its count will be one, since the master side holds an open.
1559 * Thus this test wouldn't be triggered at the time the slave closes,
1562 * Note that it's possible for the tty to be opened again while we're
1563 * flushing out waiters. By recalculating the closing flags before
1564 * each iteration we avoid any problems.
1567 /* Guard against races with tty->count changes elsewhere and
1568 opens on /dev/tty */
1570 mutex_lock(&tty_mutex);
1571 tty_closing = tty->count <= 1;
1572 o_tty_closing = o_tty &&
1573 (o_tty->count <= (pty_master ? 1 : 0));
1577 if (waitqueue_active(&tty->read_wait)) {
1578 wake_up_poll(&tty->read_wait, POLLIN);
1581 if (waitqueue_active(&tty->write_wait)) {
1582 wake_up_poll(&tty->write_wait, POLLOUT);
1586 if (o_tty_closing) {
1587 if (waitqueue_active(&o_tty->read_wait)) {
1588 wake_up_poll(&o_tty->read_wait, POLLIN);
1591 if (waitqueue_active(&o_tty->write_wait)) {
1592 wake_up_poll(&o_tty->write_wait, POLLOUT);
1599 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1600 "active!\n", tty_name(tty, buf));
1601 mutex_unlock(&tty_mutex);
1606 * The closing flags are now consistent with the open counts on
1607 * both sides, and we've completed the last operation that could
1608 * block, so it's safe to proceed with closing.
1611 if (--o_tty->count < 0) {
1612 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1614 o_tty->count, tty_name(o_tty, buf));
1618 if (--tty->count < 0) {
1619 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1620 tty->count, tty_name(tty, buf));
1625 * We've decremented tty->count, so we need to remove this file
1626 * descriptor off the tty->tty_files list; this serves two
1628 * - check_tty_count sees the correct number of file descriptors
1629 * associated with this tty.
1630 * - do_tty_hangup no longer sees this file descriptor as
1631 * something that needs to be handled for hangups.
1634 filp->private_data = NULL;
1637 * Perform some housekeeping before deciding whether to return.
1639 * Set the TTY_CLOSING flag if this was the last open. In the
1640 * case of a pty we may have to wait around for the other side
1641 * to close, and TTY_CLOSING makes sure we can't be reopened.
1644 set_bit(TTY_CLOSING, &tty->flags);
1646 set_bit(TTY_CLOSING, &o_tty->flags);
1649 * If _either_ side is closing, make sure there aren't any
1650 * processes that still think tty or o_tty is their controlling
1653 if (tty_closing || o_tty_closing) {
1654 read_lock(&tasklist_lock);
1655 session_clear_tty(tty->session);
1657 session_clear_tty(o_tty->session);
1658 read_unlock(&tasklist_lock);
1661 mutex_unlock(&tty_mutex);
1663 /* check whether both sides are closing ... */
1664 if (!tty_closing || (o_tty && !o_tty_closing))
1667 #ifdef TTY_DEBUG_HANGUP
1668 printk(KERN_DEBUG "freeing tty structure...");
1671 * Ask the line discipline code to release its structures
1673 tty_ldisc_release(tty, o_tty);
1675 * The release_tty function takes care of the details of clearing
1676 * the slots and preserving the termios structure.
1678 release_tty(tty, idx);
1680 /* Make this pty number available for reallocation */
1682 devpts_kill_index(inode, idx);
1686 * __tty_open - open a tty device
1687 * @inode: inode of device file
1688 * @filp: file pointer to tty
1690 * tty_open and tty_release keep up the tty count that contains the
1691 * number of opens done on a tty. We cannot use the inode-count, as
1692 * different inodes might point to the same tty.
1694 * Open-counting is needed for pty masters, as well as for keeping
1695 * track of serial lines: DTR is dropped when the last close happens.
1696 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1698 * The termios state of a pty is reset on first open so that
1699 * settings don't persist across reuse.
1701 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1702 * tty->count should protect the rest.
1703 * ->siglock protects ->signal/->sighand
1706 static int __tty_open(struct inode *inode, struct file *filp)
1708 struct tty_struct *tty = NULL;
1710 struct tty_driver *driver;
1712 dev_t device = inode->i_rdev;
1713 unsigned saved_flags = filp->f_flags;
1715 nonseekable_open(inode, filp);
1718 noctty = filp->f_flags & O_NOCTTY;
1722 mutex_lock(&tty_mutex);
1724 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1725 tty = get_current_tty();
1727 mutex_unlock(&tty_mutex);
1730 driver = tty_driver_kref_get(tty->driver);
1732 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1734 /* FIXME: Should we take a driver reference ? */
1739 if (device == MKDEV(TTY_MAJOR, 0)) {
1740 extern struct tty_driver *console_driver;
1741 driver = tty_driver_kref_get(console_driver);
1747 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1748 struct tty_driver *console_driver = console_device(&index);
1749 if (console_driver) {
1750 driver = tty_driver_kref_get(console_driver);
1752 /* Don't let /dev/console block */
1753 filp->f_flags |= O_NONBLOCK;
1758 mutex_unlock(&tty_mutex);
1762 driver = get_tty_driver(device, &index);
1764 mutex_unlock(&tty_mutex);
1769 /* check whether we're reopening an existing tty */
1770 tty = tty_driver_lookup_tty(driver, inode, index);
1773 mutex_unlock(&tty_mutex);
1774 return PTR_ERR(tty);
1779 retval = tty_reopen(tty);
1781 tty = ERR_PTR(retval);
1783 tty = tty_init_dev(driver, index, 0);
1785 mutex_unlock(&tty_mutex);
1786 tty_driver_kref_put(driver);
1788 return PTR_ERR(tty);
1790 filp->private_data = tty;
1791 file_move(filp, &tty->tty_files);
1792 check_tty_count(tty, "tty_open");
1793 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1794 tty->driver->subtype == PTY_TYPE_MASTER)
1796 #ifdef TTY_DEBUG_HANGUP
1797 printk(KERN_DEBUG "opening %s...", tty->name);
1801 retval = tty->ops->open(tty, filp);
1805 filp->f_flags = saved_flags;
1807 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1808 !capable(CAP_SYS_ADMIN))
1812 #ifdef TTY_DEBUG_HANGUP
1813 printk(KERN_DEBUG "error %d in opening %s...", retval,
1816 tty_release_dev(filp);
1817 if (retval != -ERESTARTSYS)
1819 if (signal_pending(current))
1823 * Need to reset f_op in case a hangup happened.
1825 if (filp->f_op == &hung_up_tty_fops)
1826 filp->f_op = &tty_fops;
1830 mutex_lock(&tty_mutex);
1831 spin_lock_irq(¤t->sighand->siglock);
1833 current->signal->leader &&
1834 !current->signal->tty &&
1835 tty->session == NULL)
1836 __proc_set_tty(current, tty);
1837 spin_unlock_irq(¤t->sighand->siglock);
1838 mutex_unlock(&tty_mutex);
1842 /* BKL pushdown: scary code avoidance wrapper */
1843 static int tty_open(struct inode *inode, struct file *filp)
1848 ret = __tty_open(inode, filp);
1857 * tty_release - vfs callback for close
1858 * @inode: inode of tty
1859 * @filp: file pointer for handle to tty
1861 * Called the last time each file handle is closed that references
1862 * this tty. There may however be several such references.
1865 * Takes bkl. See tty_release_dev
1868 static int tty_release(struct inode *inode, struct file *filp)
1871 tty_release_dev(filp);
1877 * tty_poll - check tty status
1878 * @filp: file being polled
1879 * @wait: poll wait structures to update
1881 * Call the line discipline polling method to obtain the poll
1882 * status of the device.
1884 * Locking: locks called line discipline but ldisc poll method
1885 * may be re-entered freely by other callers.
1888 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1890 struct tty_struct *tty;
1891 struct tty_ldisc *ld;
1894 tty = (struct tty_struct *)filp->private_data;
1895 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1898 ld = tty_ldisc_ref_wait(tty);
1900 ret = (ld->ops->poll)(tty, filp, wait);
1901 tty_ldisc_deref(ld);
1905 static int tty_fasync(int fd, struct file *filp, int on)
1907 struct tty_struct *tty;
1908 unsigned long flags;
1912 tty = (struct tty_struct *)filp->private_data;
1913 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1916 retval = fasync_helper(fd, filp, on, &tty->fasync);
1923 if (!waitqueue_active(&tty->read_wait))
1924 tty->minimum_to_wake = 1;
1925 spin_lock_irqsave(&tty->ctrl_lock, flags);
1928 type = PIDTYPE_PGID;
1930 pid = task_pid(current);
1933 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1934 retval = __f_setown(filp, pid, type, 0);
1938 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
1939 tty->minimum_to_wake = N_TTY_BUF_SIZE;
1948 * tiocsti - fake input character
1949 * @tty: tty to fake input into
1950 * @p: pointer to character
1952 * Fake input to a tty device. Does the necessary locking and
1955 * FIXME: does not honour flow control ??
1958 * Called functions take tty_ldisc_lock
1959 * current->signal->tty check is safe without locks
1961 * FIXME: may race normal receive processing
1964 static int tiocsti(struct tty_struct *tty, char __user *p)
1967 struct tty_ldisc *ld;
1969 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
1971 if (get_user(ch, p))
1973 tty_audit_tiocsti(tty, ch);
1974 ld = tty_ldisc_ref_wait(tty);
1975 ld->ops->receive_buf(tty, &ch, &mbz, 1);
1976 tty_ldisc_deref(ld);
1981 * tiocgwinsz - implement window query ioctl
1983 * @arg: user buffer for result
1985 * Copies the kernel idea of the window size into the user buffer.
1987 * Locking: tty->termios_mutex is taken to ensure the winsize data
1991 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
1995 mutex_lock(&tty->termios_mutex);
1996 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
1997 mutex_unlock(&tty->termios_mutex);
1999 return err ? -EFAULT: 0;
2003 * tty_do_resize - resize event
2004 * @tty: tty being resized
2005 * @rows: rows (character)
2006 * @cols: cols (character)
2008 * Update the termios variables and send the neccessary signals to
2009 * peform a terminal resize correctly
2012 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2015 unsigned long flags;
2018 mutex_lock(&tty->termios_mutex);
2019 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2021 /* Get the PID values and reference them so we can
2022 avoid holding the tty ctrl lock while sending signals */
2023 spin_lock_irqsave(&tty->ctrl_lock, flags);
2024 pgrp = get_pid(tty->pgrp);
2025 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2028 kill_pgrp(pgrp, SIGWINCH, 1);
2033 mutex_unlock(&tty->termios_mutex);
2038 * tiocswinsz - implement window size set ioctl
2039 * @tty; tty side of tty
2040 * @arg: user buffer for result
2042 * Copies the user idea of the window size to the kernel. Traditionally
2043 * this is just advisory information but for the Linux console it
2044 * actually has driver level meaning and triggers a VC resize.
2047 * Driver dependant. The default do_resize method takes the
2048 * tty termios mutex and ctrl_lock. The console takes its own lock
2049 * then calls into the default method.
2052 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2054 struct winsize tmp_ws;
2055 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2058 if (tty->ops->resize)
2059 return tty->ops->resize(tty, &tmp_ws);
2061 return tty_do_resize(tty, &tmp_ws);
2065 * tioccons - allow admin to move logical console
2066 * @file: the file to become console
2068 * Allow the adminstrator to move the redirected console device
2070 * Locking: uses redirect_lock to guard the redirect information
2073 static int tioccons(struct file *file)
2075 if (!capable(CAP_SYS_ADMIN))
2077 if (file->f_op->write == redirected_tty_write) {
2079 spin_lock(&redirect_lock);
2082 spin_unlock(&redirect_lock);
2087 spin_lock(&redirect_lock);
2089 spin_unlock(&redirect_lock);
2094 spin_unlock(&redirect_lock);
2099 * fionbio - non blocking ioctl
2100 * @file: file to set blocking value
2101 * @p: user parameter
2103 * Historical tty interfaces had a blocking control ioctl before
2104 * the generic functionality existed. This piece of history is preserved
2105 * in the expected tty API of posix OS's.
2107 * Locking: none, the open file handle ensures it won't go away.
2110 static int fionbio(struct file *file, int __user *p)
2114 if (get_user(nonblock, p))
2117 spin_lock(&file->f_lock);
2119 file->f_flags |= O_NONBLOCK;
2121 file->f_flags &= ~O_NONBLOCK;
2122 spin_unlock(&file->f_lock);
2127 * tiocsctty - set controlling tty
2128 * @tty: tty structure
2129 * @arg: user argument
2131 * This ioctl is used to manage job control. It permits a session
2132 * leader to set this tty as the controlling tty for the session.
2135 * Takes tty_mutex() to protect tty instance
2136 * Takes tasklist_lock internally to walk sessions
2137 * Takes ->siglock() when updating signal->tty
2140 static int tiocsctty(struct tty_struct *tty, int arg)
2143 if (current->signal->leader && (task_session(current) == tty->session))
2146 mutex_lock(&tty_mutex);
2148 * The process must be a session leader and
2149 * not have a controlling tty already.
2151 if (!current->signal->leader || current->signal->tty) {
2158 * This tty is already the controlling
2159 * tty for another session group!
2161 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2165 read_lock(&tasklist_lock);
2166 session_clear_tty(tty->session);
2167 read_unlock(&tasklist_lock);
2173 proc_set_tty(current, tty);
2175 mutex_unlock(&tty_mutex);
2180 * tty_get_pgrp - return a ref counted pgrp pid
2183 * Returns a refcounted instance of the pid struct for the process
2184 * group controlling the tty.
2187 struct pid *tty_get_pgrp(struct tty_struct *tty)
2189 unsigned long flags;
2192 spin_lock_irqsave(&tty->ctrl_lock, flags);
2193 pgrp = get_pid(tty->pgrp);
2194 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2198 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2201 * tiocgpgrp - get process group
2202 * @tty: tty passed by user
2203 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2206 * Obtain the process group of the tty. If there is no process group
2209 * Locking: none. Reference to current->signal->tty is safe.
2212 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2217 * (tty == real_tty) is a cheap way of
2218 * testing if the tty is NOT a master pty.
2220 if (tty == real_tty && current->signal->tty != real_tty)
2222 pid = tty_get_pgrp(real_tty);
2223 ret = put_user(pid_vnr(pid), p);
2229 * tiocspgrp - attempt to set process group
2230 * @tty: tty passed by user
2231 * @real_tty: tty side device matching tty passed by user
2234 * Set the process group of the tty to the session passed. Only
2235 * permitted where the tty session is our session.
2237 * Locking: RCU, ctrl lock
2240 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2244 int retval = tty_check_change(real_tty);
2245 unsigned long flags;
2251 if (!current->signal->tty ||
2252 (current->signal->tty != real_tty) ||
2253 (real_tty->session != task_session(current)))
2255 if (get_user(pgrp_nr, p))
2260 pgrp = find_vpid(pgrp_nr);
2265 if (session_of_pgrp(pgrp) != task_session(current))
2268 spin_lock_irqsave(&tty->ctrl_lock, flags);
2269 put_pid(real_tty->pgrp);
2270 real_tty->pgrp = get_pid(pgrp);
2271 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2278 * tiocgsid - get session id
2279 * @tty: tty passed by user
2280 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2281 * @p: pointer to returned session id
2283 * Obtain the session id of the tty. If there is no session
2286 * Locking: none. Reference to current->signal->tty is safe.
2289 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2292 * (tty == real_tty) is a cheap way of
2293 * testing if the tty is NOT a master pty.
2295 if (tty == real_tty && current->signal->tty != real_tty)
2297 if (!real_tty->session)
2299 return put_user(pid_vnr(real_tty->session), p);
2303 * tiocsetd - set line discipline
2305 * @p: pointer to user data
2307 * Set the line discipline according to user request.
2309 * Locking: see tty_set_ldisc, this function is just a helper
2312 static int tiocsetd(struct tty_struct *tty, int __user *p)
2317 if (get_user(ldisc, p))
2321 ret = tty_set_ldisc(tty, ldisc);
2328 * send_break - performed time break
2329 * @tty: device to break on
2330 * @duration: timeout in mS
2332 * Perform a timed break on hardware that lacks its own driver level
2333 * timed break functionality.
2336 * atomic_write_lock serializes
2340 static int send_break(struct tty_struct *tty, unsigned int duration)
2344 if (tty->ops->break_ctl == NULL)
2347 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2348 retval = tty->ops->break_ctl(tty, duration);
2350 /* Do the work ourselves */
2351 if (tty_write_lock(tty, 0) < 0)
2353 retval = tty->ops->break_ctl(tty, -1);
2356 if (!signal_pending(current))
2357 msleep_interruptible(duration);
2358 retval = tty->ops->break_ctl(tty, 0);
2360 tty_write_unlock(tty);
2361 if (signal_pending(current))
2368 * tty_tiocmget - get modem status
2370 * @file: user file pointer
2371 * @p: pointer to result
2373 * Obtain the modem status bits from the tty driver if the feature
2374 * is supported. Return -EINVAL if it is not available.
2376 * Locking: none (up to the driver)
2379 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2381 int retval = -EINVAL;
2383 if (tty->ops->tiocmget) {
2384 retval = tty->ops->tiocmget(tty, file);
2387 retval = put_user(retval, p);
2393 * tty_tiocmset - set modem status
2395 * @file: user file pointer
2396 * @cmd: command - clear bits, set bits or set all
2397 * @p: pointer to desired bits
2399 * Set the modem status bits from the tty driver if the feature
2400 * is supported. Return -EINVAL if it is not available.
2402 * Locking: none (up to the driver)
2405 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2409 unsigned int set, clear, val;
2411 if (tty->ops->tiocmset == NULL)
2414 retval = get_user(val, p);
2430 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2431 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2432 return tty->ops->tiocmset(tty, file, set, clear);
2435 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2437 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2438 tty->driver->subtype == PTY_TYPE_MASTER)
2442 EXPORT_SYMBOL(tty_pair_get_tty);
2444 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2446 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2447 tty->driver->subtype == PTY_TYPE_MASTER)
2451 EXPORT_SYMBOL(tty_pair_get_pty);
2454 * Split this up, as gcc can choke on it otherwise..
2456 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2458 struct tty_struct *tty, *real_tty;
2459 void __user *p = (void __user *)arg;
2461 struct tty_ldisc *ld;
2462 struct inode *inode = file->f_dentry->d_inode;
2464 tty = (struct tty_struct *)file->private_data;
2465 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2468 real_tty = tty_pair_get_tty(tty);
2471 * Factor out some common prep work
2479 retval = tty_check_change(tty);
2482 if (cmd != TIOCCBRK) {
2483 tty_wait_until_sent(tty, 0);
2484 if (signal_pending(current))
2495 return tiocsti(tty, p);
2497 return tiocgwinsz(real_tty, p);
2499 return tiocswinsz(real_tty, p);
2501 return real_tty != tty ? -EINVAL : tioccons(file);
2503 return fionbio(file, p);
2505 set_bit(TTY_EXCLUSIVE, &tty->flags);
2508 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2511 if (current->signal->tty != tty)
2516 return tiocsctty(tty, arg);
2518 return tiocgpgrp(tty, real_tty, p);
2520 return tiocspgrp(tty, real_tty, p);
2522 return tiocgsid(tty, real_tty, p);
2524 return put_user(tty->ldisc->ops->num, (int __user *)p);
2526 return tiocsetd(tty, p);
2530 case TIOCSBRK: /* Turn break on, unconditionally */
2531 if (tty->ops->break_ctl)
2532 return tty->ops->break_ctl(tty, -1);
2534 case TIOCCBRK: /* Turn break off, unconditionally */
2535 if (tty->ops->break_ctl)
2536 return tty->ops->break_ctl(tty, 0);
2538 case TCSBRK: /* SVID version: non-zero arg --> no break */
2539 /* non-zero arg means wait for all output data
2540 * to be sent (performed above) but don't send break.
2541 * This is used by the tcdrain() termios function.
2544 return send_break(tty, 250);
2546 case TCSBRKP: /* support for POSIX tcsendbreak() */
2547 return send_break(tty, arg ? arg*100 : 250);
2550 return tty_tiocmget(tty, file, p);
2554 return tty_tiocmset(tty, file, cmd, p);
2559 /* flush tty buffer and allow ldisc to process ioctl */
2560 tty_buffer_flush(tty);
2565 if (tty->ops->ioctl) {
2566 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2567 if (retval != -ENOIOCTLCMD)
2570 ld = tty_ldisc_ref_wait(tty);
2572 if (ld->ops->ioctl) {
2573 retval = ld->ops->ioctl(tty, file, cmd, arg);
2574 if (retval == -ENOIOCTLCMD)
2577 tty_ldisc_deref(ld);
2581 #ifdef CONFIG_COMPAT
2582 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2585 struct inode *inode = file->f_dentry->d_inode;
2586 struct tty_struct *tty = file->private_data;
2587 struct tty_ldisc *ld;
2588 int retval = -ENOIOCTLCMD;
2590 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2593 if (tty->ops->compat_ioctl) {
2594 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2595 if (retval != -ENOIOCTLCMD)
2599 ld = tty_ldisc_ref_wait(tty);
2600 if (ld->ops->compat_ioctl)
2601 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2602 tty_ldisc_deref(ld);
2609 * This implements the "Secure Attention Key" --- the idea is to
2610 * prevent trojan horses by killing all processes associated with this
2611 * tty when the user hits the "Secure Attention Key". Required for
2612 * super-paranoid applications --- see the Orange Book for more details.
2614 * This code could be nicer; ideally it should send a HUP, wait a few
2615 * seconds, then send a INT, and then a KILL signal. But you then
2616 * have to coordinate with the init process, since all processes associated
2617 * with the current tty must be dead before the new getty is allowed
2620 * Now, if it would be correct ;-/ The current code has a nasty hole -
2621 * it doesn't catch files in flight. We may send the descriptor to ourselves
2622 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2624 * Nasty bug: do_SAK is being called in interrupt context. This can
2625 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2627 void __do_SAK(struct tty_struct *tty)
2632 struct task_struct *g, *p;
2633 struct pid *session;
2636 struct fdtable *fdt;
2640 session = tty->session;
2642 tty_ldisc_flush(tty);
2644 tty_driver_flush_buffer(tty);
2646 read_lock(&tasklist_lock);
2647 /* Kill the entire session */
2648 do_each_pid_task(session, PIDTYPE_SID, p) {
2649 printk(KERN_NOTICE "SAK: killed process %d"
2650 " (%s): task_session(p)==tty->session\n",
2651 task_pid_nr(p), p->comm);
2652 send_sig(SIGKILL, p, 1);
2653 } while_each_pid_task(session, PIDTYPE_SID, p);
2654 /* Now kill any processes that happen to have the
2657 do_each_thread(g, p) {
2658 if (p->signal->tty == tty) {
2659 printk(KERN_NOTICE "SAK: killed process %d"
2660 " (%s): task_session(p)==tty->session\n",
2661 task_pid_nr(p), p->comm);
2662 send_sig(SIGKILL, p, 1);
2668 * We don't take a ref to the file, so we must
2669 * hold ->file_lock instead.
2671 spin_lock(&p->files->file_lock);
2672 fdt = files_fdtable(p->files);
2673 for (i = 0; i < fdt->max_fds; i++) {
2674 filp = fcheck_files(p->files, i);
2677 if (filp->f_op->read == tty_read &&
2678 filp->private_data == tty) {
2679 printk(KERN_NOTICE "SAK: killed process %d"
2680 " (%s): fd#%d opened to the tty\n",
2681 task_pid_nr(p), p->comm, i);
2682 force_sig(SIGKILL, p);
2686 spin_unlock(&p->files->file_lock);
2689 } while_each_thread(g, p);
2690 read_unlock(&tasklist_lock);
2694 static void do_SAK_work(struct work_struct *work)
2696 struct tty_struct *tty =
2697 container_of(work, struct tty_struct, SAK_work);
2702 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2703 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2704 * the values which we write to it will be identical to the values which it
2705 * already has. --akpm
2707 void do_SAK(struct tty_struct *tty)
2711 schedule_work(&tty->SAK_work);
2714 EXPORT_SYMBOL(do_SAK);
2717 * initialize_tty_struct
2718 * @tty: tty to initialize
2720 * This subroutine initializes a tty structure that has been newly
2723 * Locking: none - tty in question must not be exposed at this point
2726 void initialize_tty_struct(struct tty_struct *tty,
2727 struct tty_driver *driver, int idx)
2729 memset(tty, 0, sizeof(struct tty_struct));
2730 kref_init(&tty->kref);
2731 tty->magic = TTY_MAGIC;
2732 tty_ldisc_init(tty);
2733 tty->session = NULL;
2735 tty->overrun_time = jiffies;
2736 tty->buf.head = tty->buf.tail = NULL;
2737 tty_buffer_init(tty);
2738 mutex_init(&tty->termios_mutex);
2739 mutex_init(&tty->ldisc_mutex);
2740 init_waitqueue_head(&tty->write_wait);
2741 init_waitqueue_head(&tty->read_wait);
2742 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2743 mutex_init(&tty->atomic_read_lock);
2744 mutex_init(&tty->atomic_write_lock);
2745 mutex_init(&tty->output_lock);
2746 mutex_init(&tty->echo_lock);
2747 spin_lock_init(&tty->read_lock);
2748 spin_lock_init(&tty->ctrl_lock);
2749 INIT_LIST_HEAD(&tty->tty_files);
2750 INIT_WORK(&tty->SAK_work, do_SAK_work);
2752 tty->driver = driver;
2753 tty->ops = driver->ops;
2755 tty_line_name(driver, idx, tty->name);
2759 * tty_put_char - write one character to a tty
2763 * Write one byte to the tty using the provided put_char method
2764 * if present. Returns the number of characters successfully output.
2766 * Note: the specific put_char operation in the driver layer may go
2767 * away soon. Don't call it directly, use this method
2770 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2772 if (tty->ops->put_char)
2773 return tty->ops->put_char(tty, ch);
2774 return tty->ops->write(tty, &ch, 1);
2776 EXPORT_SYMBOL_GPL(tty_put_char);
2778 struct class *tty_class;
2781 * tty_register_device - register a tty device
2782 * @driver: the tty driver that describes the tty device
2783 * @index: the index in the tty driver for this tty device
2784 * @device: a struct device that is associated with this tty device.
2785 * This field is optional, if there is no known struct device
2786 * for this tty device it can be set to NULL safely.
2788 * Returns a pointer to the struct device for this tty device
2789 * (or ERR_PTR(-EFOO) on error).
2791 * This call is required to be made to register an individual tty device
2792 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2793 * that bit is not set, this function should not be called by a tty
2799 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2800 struct device *device)
2803 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2805 if (index >= driver->num) {
2806 printk(KERN_ERR "Attempt to register invalid tty line number "
2808 return ERR_PTR(-EINVAL);
2811 if (driver->type == TTY_DRIVER_TYPE_PTY)
2812 pty_line_name(driver, index, name);
2814 tty_line_name(driver, index, name);
2816 return device_create(tty_class, device, dev, NULL, name);
2818 EXPORT_SYMBOL(tty_register_device);
2821 * tty_unregister_device - unregister a tty device
2822 * @driver: the tty driver that describes the tty device
2823 * @index: the index in the tty driver for this tty device
2825 * If a tty device is registered with a call to tty_register_device() then
2826 * this function must be called when the tty device is gone.
2831 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2833 device_destroy(tty_class,
2834 MKDEV(driver->major, driver->minor_start) + index);
2836 EXPORT_SYMBOL(tty_unregister_device);
2838 struct tty_driver *alloc_tty_driver(int lines)
2840 struct tty_driver *driver;
2842 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2844 kref_init(&driver->kref);
2845 driver->magic = TTY_DRIVER_MAGIC;
2846 driver->num = lines;
2847 /* later we'll move allocation of tables here */
2851 EXPORT_SYMBOL(alloc_tty_driver);
2853 static void destruct_tty_driver(struct kref *kref)
2855 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2857 struct ktermios *tp;
2860 if (driver->flags & TTY_DRIVER_INSTALLED) {
2862 * Free the termios and termios_locked structures because
2863 * we don't want to get memory leaks when modular tty
2864 * drivers are removed from the kernel.
2866 for (i = 0; i < driver->num; i++) {
2867 tp = driver->termios[i];
2869 driver->termios[i] = NULL;
2872 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2873 tty_unregister_device(driver, i);
2876 proc_tty_unregister_driver(driver);
2877 driver->ttys = NULL;
2878 driver->termios = NULL;
2880 cdev_del(&driver->cdev);
2885 void tty_driver_kref_put(struct tty_driver *driver)
2887 kref_put(&driver->kref, destruct_tty_driver);
2889 EXPORT_SYMBOL(tty_driver_kref_put);
2891 void tty_set_operations(struct tty_driver *driver,
2892 const struct tty_operations *op)
2896 EXPORT_SYMBOL(tty_set_operations);
2898 void put_tty_driver(struct tty_driver *d)
2900 tty_driver_kref_put(d);
2902 EXPORT_SYMBOL(put_tty_driver);
2905 * Called by a tty driver to register itself.
2907 int tty_register_driver(struct tty_driver *driver)
2914 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2915 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2920 if (!driver->major) {
2921 error = alloc_chrdev_region(&dev, driver->minor_start,
2922 driver->num, driver->name);
2924 driver->major = MAJOR(dev);
2925 driver->minor_start = MINOR(dev);
2928 dev = MKDEV(driver->major, driver->minor_start);
2929 error = register_chrdev_region(dev, driver->num, driver->name);
2937 driver->ttys = (struct tty_struct **)p;
2938 driver->termios = (struct ktermios **)(p + driver->num);
2940 driver->ttys = NULL;
2941 driver->termios = NULL;
2944 cdev_init(&driver->cdev, &tty_fops);
2945 driver->cdev.owner = driver->owner;
2946 error = cdev_add(&driver->cdev, dev, driver->num);
2948 unregister_chrdev_region(dev, driver->num);
2949 driver->ttys = NULL;
2950 driver->termios = NULL;
2955 mutex_lock(&tty_mutex);
2956 list_add(&driver->tty_drivers, &tty_drivers);
2957 mutex_unlock(&tty_mutex);
2959 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
2960 for (i = 0; i < driver->num; i++)
2961 tty_register_device(driver, i, NULL);
2963 proc_tty_register_driver(driver);
2964 driver->flags |= TTY_DRIVER_INSTALLED;
2968 EXPORT_SYMBOL(tty_register_driver);
2971 * Called by a tty driver to unregister itself.
2973 int tty_unregister_driver(struct tty_driver *driver)
2977 if (driver->refcount)
2980 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
2982 mutex_lock(&tty_mutex);
2983 list_del(&driver->tty_drivers);
2984 mutex_unlock(&tty_mutex);
2988 EXPORT_SYMBOL(tty_unregister_driver);
2990 dev_t tty_devnum(struct tty_struct *tty)
2992 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
2994 EXPORT_SYMBOL(tty_devnum);
2996 void proc_clear_tty(struct task_struct *p)
2998 unsigned long flags;
2999 struct tty_struct *tty;
3000 spin_lock_irqsave(&p->sighand->siglock, flags);
3001 tty = p->signal->tty;
3002 p->signal->tty = NULL;
3003 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3007 /* Called under the sighand lock */
3009 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3012 unsigned long flags;
3013 /* We should not have a session or pgrp to put here but.... */
3014 spin_lock_irqsave(&tty->ctrl_lock, flags);
3015 put_pid(tty->session);
3017 tty->pgrp = get_pid(task_pgrp(tsk));
3018 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3019 tty->session = get_pid(task_session(tsk));
3020 if (tsk->signal->tty) {
3021 printk(KERN_DEBUG "tty not NULL!!\n");
3022 tty_kref_put(tsk->signal->tty);
3025 put_pid(tsk->signal->tty_old_pgrp);
3026 tsk->signal->tty = tty_kref_get(tty);
3027 tsk->signal->tty_old_pgrp = NULL;
3030 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3032 spin_lock_irq(&tsk->sighand->siglock);
3033 __proc_set_tty(tsk, tty);
3034 spin_unlock_irq(&tsk->sighand->siglock);
3037 struct tty_struct *get_current_tty(void)
3039 struct tty_struct *tty;
3040 unsigned long flags;
3042 spin_lock_irqsave(¤t->sighand->siglock, flags);
3043 tty = tty_kref_get(current->signal->tty);
3044 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3047 EXPORT_SYMBOL_GPL(get_current_tty);
3049 void tty_default_fops(struct file_operations *fops)
3055 * Initialize the console device. This is called *early*, so
3056 * we can't necessarily depend on lots of kernel help here.
3057 * Just do some early initializations, and do the complex setup
3060 void __init console_init(void)
3064 /* Setup the default TTY line discipline. */
3068 * set up the console device so that later boot sequences can
3069 * inform about problems etc..
3071 call = __con_initcall_start;
3072 while (call < __con_initcall_end) {
3078 static char *tty_devnode(struct device *dev, mode_t *mode)
3082 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3083 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3088 static int __init tty_class_init(void)
3090 tty_class = class_create(THIS_MODULE, "tty");
3091 if (IS_ERR(tty_class))
3092 return PTR_ERR(tty_class);
3093 tty_class->devnode = tty_devnode;
3097 postcore_initcall(tty_class_init);
3099 /* 3/2004 jmc: why do these devices exist? */
3101 static struct cdev tty_cdev, console_cdev;
3104 * Ok, now we can initialize the rest of the tty devices and can count
3105 * on memory allocations, interrupts etc..
3107 static int __init tty_init(void)
3109 cdev_init(&tty_cdev, &tty_fops);
3110 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3111 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3112 panic("Couldn't register /dev/tty driver\n");
3113 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3116 cdev_init(&console_cdev, &console_fops);
3117 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3118 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3119 panic("Couldn't register /dev/console driver\n");
3120 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3124 vty_init(&console_fops);
3128 module_init(tty_init);