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>
99 #include <linux/serial.h>
101 #include <linux/uaccess.h>
102 #include <asm/system.h>
104 #include <linux/kbd_kern.h>
105 #include <linux/vt_kern.h>
106 #include <linux/selection.h>
108 #include <linux/kmod.h>
109 #include <linux/nsproxy.h>
111 #undef TTY_DEBUG_HANGUP
113 #define TTY_PARANOIA_CHECK 1
114 #define CHECK_TTY_COUNT 1
116 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
117 .c_iflag = ICRNL | IXON,
118 .c_oflag = OPOST | ONLCR,
119 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
120 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
121 ECHOCTL | ECHOKE | IEXTEN,
127 EXPORT_SYMBOL(tty_std_termios);
129 /* This list gets poked at by procfs and various bits of boot up code. This
130 could do with some rationalisation such as pulling the tty proc function
133 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
135 /* Mutex to protect creating and releasing a tty. This is shared with
136 vt.c for deeply disgusting hack reasons */
137 DEFINE_MUTEX(tty_mutex);
138 EXPORT_SYMBOL(tty_mutex);
140 /* Spinlock to protect the tty->tty_files list */
141 DEFINE_SPINLOCK(tty_files_lock);
143 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
144 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
145 ssize_t redirected_tty_write(struct file *, const char __user *,
147 static unsigned int tty_poll(struct file *, poll_table *);
148 static int tty_open(struct inode *, struct file *);
149 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
151 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
154 #define tty_compat_ioctl NULL
156 static int __tty_fasync(int fd, struct file *filp, int on);
157 static int tty_fasync(int fd, struct file *filp, int on);
158 static void release_tty(struct tty_struct *tty, int idx);
159 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
160 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
163 * alloc_tty_struct - allocate a tty object
165 * Return a new empty tty structure. The data fields have not
166 * been initialized in any way but has been zeroed
171 struct tty_struct *alloc_tty_struct(void)
173 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
177 * free_tty_struct - free a disused tty
178 * @tty: tty struct to free
180 * Free the write buffers, tty queue and tty memory itself.
182 * Locking: none. Must be called after tty is definitely unused
185 void free_tty_struct(struct tty_struct *tty)
188 put_device(tty->dev);
189 kfree(tty->write_buf);
190 tty_buffer_free_all(tty);
194 static inline struct tty_struct *file_tty(struct file *file)
196 return ((struct tty_file_private *)file->private_data)->tty;
199 /* Associate a new file with the tty structure */
200 int tty_add_file(struct tty_struct *tty, struct file *file)
202 struct tty_file_private *priv;
204 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
210 file->private_data = priv;
212 spin_lock(&tty_files_lock);
213 list_add(&priv->list, &tty->tty_files);
214 spin_unlock(&tty_files_lock);
219 /* Delete file from its tty */
220 void tty_del_file(struct file *file)
222 struct tty_file_private *priv = file->private_data;
224 spin_lock(&tty_files_lock);
225 list_del(&priv->list);
226 spin_unlock(&tty_files_lock);
227 file->private_data = NULL;
232 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
235 * tty_name - return tty naming
236 * @tty: tty structure
237 * @buf: buffer for output
239 * Convert a tty structure into a name. The name reflects the kernel
240 * naming policy and if udev is in use may not reflect user space
245 char *tty_name(struct tty_struct *tty, char *buf)
247 if (!tty) /* Hmm. NULL pointer. That's fun. */
248 strcpy(buf, "NULL tty");
250 strcpy(buf, tty->name);
254 EXPORT_SYMBOL(tty_name);
256 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
259 #ifdef TTY_PARANOIA_CHECK
262 "null TTY for (%d:%d) in %s\n",
263 imajor(inode), iminor(inode), routine);
266 if (tty->magic != TTY_MAGIC) {
268 "bad magic number for tty struct (%d:%d) in %s\n",
269 imajor(inode), iminor(inode), routine);
276 static int check_tty_count(struct tty_struct *tty, const char *routine)
278 #ifdef CHECK_TTY_COUNT
282 spin_lock(&tty_files_lock);
283 list_for_each(p, &tty->tty_files) {
286 spin_unlock(&tty_files_lock);
287 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
288 tty->driver->subtype == PTY_TYPE_SLAVE &&
289 tty->link && tty->link->count)
291 if (tty->count != count) {
292 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
293 "!= #fd's(%d) in %s\n",
294 tty->name, tty->count, count, routine);
302 * get_tty_driver - find device of a tty
303 * @dev_t: device identifier
304 * @index: returns the index of the tty
306 * This routine returns a tty driver structure, given a device number
307 * and also passes back the index number.
309 * Locking: caller must hold tty_mutex
312 static struct tty_driver *get_tty_driver(dev_t device, int *index)
314 struct tty_driver *p;
316 list_for_each_entry(p, &tty_drivers, tty_drivers) {
317 dev_t base = MKDEV(p->major, p->minor_start);
318 if (device < base || device >= base + p->num)
320 *index = device - base;
321 return tty_driver_kref_get(p);
326 #ifdef CONFIG_CONSOLE_POLL
329 * tty_find_polling_driver - find device of a polled tty
330 * @name: name string to match
331 * @line: pointer to resulting tty line nr
333 * This routine returns a tty driver structure, given a name
334 * and the condition that the tty driver is capable of polled
337 struct tty_driver *tty_find_polling_driver(char *name, int *line)
339 struct tty_driver *p, *res = NULL;
344 for (str = name; *str; str++)
345 if ((*str >= '0' && *str <= '9') || *str == ',')
351 tty_line = simple_strtoul(str, &str, 10);
353 mutex_lock(&tty_mutex);
354 /* Search through the tty devices to look for a match */
355 list_for_each_entry(p, &tty_drivers, tty_drivers) {
356 if (strncmp(name, p->name, len) != 0)
364 if (tty_line >= 0 && tty_line < p->num && p->ops &&
365 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
366 res = tty_driver_kref_get(p);
371 mutex_unlock(&tty_mutex);
375 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
379 * tty_check_change - check for POSIX terminal changes
382 * If we try to write to, or set the state of, a terminal and we're
383 * not in the foreground, send a SIGTTOU. If the signal is blocked or
384 * ignored, go ahead and perform the operation. (POSIX 7.2)
389 int tty_check_change(struct tty_struct *tty)
394 if (current->signal->tty != tty)
397 spin_lock_irqsave(&tty->ctrl_lock, flags);
400 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
403 if (task_pgrp(current) == tty->pgrp)
405 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
406 if (is_ignored(SIGTTOU))
408 if (is_current_pgrp_orphaned()) {
412 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
413 set_thread_flag(TIF_SIGPENDING);
418 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
422 EXPORT_SYMBOL(tty_check_change);
424 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
425 size_t count, loff_t *ppos)
430 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
431 size_t count, loff_t *ppos)
436 /* No kernel lock held - none needed ;) */
437 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
439 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
442 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
445 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
448 static long hung_up_tty_compat_ioctl(struct file *file,
449 unsigned int cmd, unsigned long arg)
451 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
454 static const struct file_operations tty_fops = {
459 .unlocked_ioctl = tty_ioctl,
460 .compat_ioctl = tty_compat_ioctl,
462 .release = tty_release,
463 .fasync = tty_fasync,
466 static const struct file_operations console_fops = {
469 .write = redirected_tty_write,
471 .unlocked_ioctl = tty_ioctl,
472 .compat_ioctl = tty_compat_ioctl,
474 .release = tty_release,
475 .fasync = tty_fasync,
478 static const struct file_operations hung_up_tty_fops = {
480 .read = hung_up_tty_read,
481 .write = hung_up_tty_write,
482 .poll = hung_up_tty_poll,
483 .unlocked_ioctl = hung_up_tty_ioctl,
484 .compat_ioctl = hung_up_tty_compat_ioctl,
485 .release = tty_release,
488 static DEFINE_SPINLOCK(redirect_lock);
489 static struct file *redirect;
492 * tty_wakeup - request more data
495 * Internal and external helper for wakeups of tty. This function
496 * informs the line discipline if present that the driver is ready
497 * to receive more output data.
500 void tty_wakeup(struct tty_struct *tty)
502 struct tty_ldisc *ld;
504 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
505 ld = tty_ldisc_ref(tty);
507 if (ld->ops->write_wakeup)
508 ld->ops->write_wakeup(tty);
512 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
515 EXPORT_SYMBOL_GPL(tty_wakeup);
518 * __tty_hangup - actual handler for hangup events
521 * This can be called by the "eventd" kernel thread. That is process
522 * synchronous but doesn't hold any locks, so we need to make sure we
523 * have the appropriate locks for what we're doing.
525 * The hangup event clears any pending redirections onto the hung up
526 * device. It ensures future writes will error and it does the needed
527 * line discipline hangup and signal delivery. The tty object itself
532 * redirect lock for undoing redirection
533 * file list lock for manipulating list of ttys
534 * tty_ldisc_lock from called functions
535 * termios_mutex resetting termios data
536 * tasklist_lock to walk task list for hangup event
537 * ->siglock to protect ->signal/->sighand
539 void __tty_hangup(struct tty_struct *tty)
541 struct file *cons_filp = NULL;
542 struct file *filp, *f = NULL;
543 struct task_struct *p;
544 struct tty_file_private *priv;
545 int closecount = 0, n;
553 spin_lock(&redirect_lock);
554 if (redirect && file_tty(redirect) == tty) {
558 spin_unlock(&redirect_lock);
562 /* inuse_filps is protected by the single tty lock,
563 this really needs to change if we want to flush the
564 workqueue with the lock held */
565 check_tty_count(tty, "tty_hangup");
567 spin_lock(&tty_files_lock);
568 /* This breaks for file handles being sent over AF_UNIX sockets ? */
569 list_for_each_entry(priv, &tty->tty_files, list) {
571 if (filp->f_op->write == redirected_tty_write)
573 if (filp->f_op->write != tty_write)
576 __tty_fasync(-1, filp, 0); /* can't block */
577 filp->f_op = &hung_up_tty_fops;
579 spin_unlock(&tty_files_lock);
581 tty_ldisc_hangup(tty);
583 read_lock(&tasklist_lock);
585 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
586 spin_lock_irq(&p->sighand->siglock);
587 if (p->signal->tty == tty) {
588 p->signal->tty = NULL;
589 /* We defer the dereferences outside fo
593 if (!p->signal->leader) {
594 spin_unlock_irq(&p->sighand->siglock);
597 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
598 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
599 put_pid(p->signal->tty_old_pgrp); /* A noop */
600 spin_lock_irqsave(&tty->ctrl_lock, flags);
602 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
603 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
604 spin_unlock_irq(&p->sighand->siglock);
605 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
607 read_unlock(&tasklist_lock);
609 spin_lock_irqsave(&tty->ctrl_lock, flags);
610 clear_bit(TTY_THROTTLED, &tty->flags);
611 clear_bit(TTY_PUSH, &tty->flags);
612 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
613 put_pid(tty->session);
617 tty->ctrl_status = 0;
618 set_bit(TTY_HUPPED, &tty->flags);
619 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
621 /* Account for the p->signal references we killed */
626 * If one of the devices matches a console pointer, we
627 * cannot just call hangup() because that will cause
628 * tty->count and state->count to go out of sync.
629 * So we just call close() the right number of times.
633 for (n = 0; n < closecount; n++)
634 tty->ops->close(tty, cons_filp);
635 } else if (tty->ops->hangup)
636 (tty->ops->hangup)(tty);
638 * We don't want to have driver/ldisc interactions beyond
639 * the ones we did here. The driver layer expects no
640 * calls after ->hangup() from the ldisc side. However we
641 * can't yet guarantee all that.
643 set_bit(TTY_HUPPED, &tty->flags);
644 tty_ldisc_enable(tty);
652 static void do_tty_hangup(struct work_struct *work)
654 struct tty_struct *tty =
655 container_of(work, struct tty_struct, hangup_work);
661 * tty_hangup - trigger a hangup event
662 * @tty: tty to hangup
664 * A carrier loss (virtual or otherwise) has occurred on this like
665 * schedule a hangup sequence to run after this event.
668 void tty_hangup(struct tty_struct *tty)
670 #ifdef TTY_DEBUG_HANGUP
672 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
674 schedule_work(&tty->hangup_work);
677 EXPORT_SYMBOL(tty_hangup);
680 * tty_vhangup - process vhangup
681 * @tty: tty to hangup
683 * The user has asked via system call for the terminal to be hung up.
684 * We do this synchronously so that when the syscall returns the process
685 * is complete. That guarantee is necessary for security reasons.
688 void tty_vhangup(struct tty_struct *tty)
690 #ifdef TTY_DEBUG_HANGUP
693 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
698 EXPORT_SYMBOL(tty_vhangup);
702 * tty_vhangup_self - process vhangup for own ctty
704 * Perform a vhangup on the current controlling tty
707 void tty_vhangup_self(void)
709 struct tty_struct *tty;
711 tty = get_current_tty();
719 * tty_hung_up_p - was tty hung up
720 * @filp: file pointer of tty
722 * Return true if the tty has been subject to a vhangup or a carrier
726 int tty_hung_up_p(struct file *filp)
728 return (filp->f_op == &hung_up_tty_fops);
731 EXPORT_SYMBOL(tty_hung_up_p);
733 static void session_clear_tty(struct pid *session)
735 struct task_struct *p;
736 do_each_pid_task(session, PIDTYPE_SID, p) {
738 } while_each_pid_task(session, PIDTYPE_SID, p);
742 * disassociate_ctty - disconnect controlling tty
743 * @on_exit: true if exiting so need to "hang up" the session
745 * This function is typically called only by the session leader, when
746 * it wants to disassociate itself from its controlling tty.
748 * It performs the following functions:
749 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
750 * (2) Clears the tty from being controlling the session
751 * (3) Clears the controlling tty for all processes in the
754 * The argument on_exit is set to 1 if called when a process is
755 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
758 * BTM is taken for hysterical raisins, and held when
759 * called from no_tty().
760 * tty_mutex is taken to protect tty
761 * ->siglock is taken to protect ->signal/->sighand
762 * tasklist_lock is taken to walk process list for sessions
763 * ->siglock is taken to protect ->signal/->sighand
766 void disassociate_ctty(int on_exit)
768 struct tty_struct *tty;
769 struct pid *tty_pgrp = NULL;
771 if (!current->signal->leader)
774 tty = get_current_tty();
776 tty_pgrp = get_pid(tty->pgrp);
778 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
782 } else if (on_exit) {
783 struct pid *old_pgrp;
784 spin_lock_irq(¤t->sighand->siglock);
785 old_pgrp = current->signal->tty_old_pgrp;
786 current->signal->tty_old_pgrp = NULL;
787 spin_unlock_irq(¤t->sighand->siglock);
789 kill_pgrp(old_pgrp, SIGHUP, on_exit);
790 kill_pgrp(old_pgrp, SIGCONT, on_exit);
796 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
798 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
802 spin_lock_irq(¤t->sighand->siglock);
803 put_pid(current->signal->tty_old_pgrp);
804 current->signal->tty_old_pgrp = NULL;
805 spin_unlock_irq(¤t->sighand->siglock);
807 tty = get_current_tty();
810 spin_lock_irqsave(&tty->ctrl_lock, flags);
811 put_pid(tty->session);
815 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
818 #ifdef TTY_DEBUG_HANGUP
819 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
824 /* Now clear signal->tty under the lock */
825 read_lock(&tasklist_lock);
826 session_clear_tty(task_session(current));
827 read_unlock(&tasklist_lock);
832 * no_tty - Ensure the current process does not have a controlling tty
836 struct task_struct *tsk = current;
838 disassociate_ctty(0);
845 * stop_tty - propagate flow control
848 * Perform flow control to the driver. For PTY/TTY pairs we
849 * must also propagate the TIOCKPKT status. May be called
850 * on an already stopped device and will not re-call the driver
853 * This functionality is used by both the line disciplines for
854 * halting incoming flow and by the driver. It may therefore be
855 * called from any context, may be under the tty atomic_write_lock
859 * Uses the tty control lock internally
862 void stop_tty(struct tty_struct *tty)
865 spin_lock_irqsave(&tty->ctrl_lock, flags);
867 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
871 if (tty->link && tty->link->packet) {
872 tty->ctrl_status &= ~TIOCPKT_START;
873 tty->ctrl_status |= TIOCPKT_STOP;
874 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
876 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
878 (tty->ops->stop)(tty);
881 EXPORT_SYMBOL(stop_tty);
884 * start_tty - propagate flow control
887 * Start a tty that has been stopped if at all possible. Perform
888 * any necessary wakeups and propagate the TIOCPKT status. If this
889 * is the tty was previous stopped and is being started then the
890 * driver start method is invoked and the line discipline woken.
896 void start_tty(struct tty_struct *tty)
899 spin_lock_irqsave(&tty->ctrl_lock, flags);
900 if (!tty->stopped || tty->flow_stopped) {
901 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
905 if (tty->link && tty->link->packet) {
906 tty->ctrl_status &= ~TIOCPKT_STOP;
907 tty->ctrl_status |= TIOCPKT_START;
908 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
910 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
912 (tty->ops->start)(tty);
913 /* If we have a running line discipline it may need kicking */
917 EXPORT_SYMBOL(start_tty);
920 * tty_read - read method for tty device files
921 * @file: pointer to tty file
923 * @count: size of user buffer
926 * Perform the read system call function on this terminal device. Checks
927 * for hung up devices before calling the line discipline method.
930 * Locks the line discipline internally while needed. Multiple
931 * read calls may be outstanding in parallel.
934 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
938 struct inode *inode = file->f_path.dentry->d_inode;
939 struct tty_struct *tty = file_tty(file);
940 struct tty_ldisc *ld;
942 if (tty_paranoia_check(tty, inode, "tty_read"))
944 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
947 /* We want to wait for the line discipline to sort out in this
949 ld = tty_ldisc_ref_wait(tty);
951 i = (ld->ops->read)(tty, file, buf, count);
956 inode->i_atime = current_fs_time(inode->i_sb);
960 void tty_write_unlock(struct tty_struct *tty)
962 mutex_unlock(&tty->atomic_write_lock);
963 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
966 int tty_write_lock(struct tty_struct *tty, int ndelay)
968 if (!mutex_trylock(&tty->atomic_write_lock)) {
971 if (mutex_lock_interruptible(&tty->atomic_write_lock))
978 * Split writes up in sane blocksizes to avoid
979 * denial-of-service type attacks
981 static inline ssize_t do_tty_write(
982 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
983 struct tty_struct *tty,
985 const char __user *buf,
988 ssize_t ret, written = 0;
991 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
996 * We chunk up writes into a temporary buffer. This
997 * simplifies low-level drivers immensely, since they
998 * don't have locking issues and user mode accesses.
1000 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1003 * The default chunk-size is 2kB, because the NTTY
1004 * layer has problems with bigger chunks. It will
1005 * claim to be able to handle more characters than
1008 * FIXME: This can probably go away now except that 64K chunks
1009 * are too likely to fail unless switched to vmalloc...
1012 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1017 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1018 if (tty->write_cnt < chunk) {
1019 unsigned char *buf_chunk;
1024 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1029 kfree(tty->write_buf);
1030 tty->write_cnt = chunk;
1031 tty->write_buf = buf_chunk;
1034 /* Do the write .. */
1036 size_t size = count;
1040 if (copy_from_user(tty->write_buf, buf, size))
1042 ret = write(tty, file, tty->write_buf, size);
1051 if (signal_pending(current))
1056 struct inode *inode = file->f_path.dentry->d_inode;
1057 inode->i_mtime = current_fs_time(inode->i_sb);
1061 tty_write_unlock(tty);
1066 * tty_write_message - write a message to a certain tty, not just the console.
1067 * @tty: the destination tty_struct
1068 * @msg: the message to write
1070 * This is used for messages that need to be redirected to a specific tty.
1071 * We don't put it into the syslog queue right now maybe in the future if
1074 * We must still hold the BTM and test the CLOSING flag for the moment.
1077 void tty_write_message(struct tty_struct *tty, char *msg)
1080 mutex_lock(&tty->atomic_write_lock);
1082 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1084 tty->ops->write(tty, msg, strlen(msg));
1087 tty_write_unlock(tty);
1094 * tty_write - write method for tty device file
1095 * @file: tty file pointer
1096 * @buf: user data to write
1097 * @count: bytes to write
1100 * Write data to a tty device via the line discipline.
1103 * Locks the line discipline as required
1104 * Writes to the tty driver are serialized by the atomic_write_lock
1105 * and are then processed in chunks to the device. The line discipline
1106 * write method will not be invoked in parallel for each device.
1109 static ssize_t tty_write(struct file *file, const char __user *buf,
1110 size_t count, loff_t *ppos)
1112 struct inode *inode = file->f_path.dentry->d_inode;
1113 struct tty_struct *tty = file_tty(file);
1114 struct tty_ldisc *ld;
1117 if (tty_paranoia_check(tty, inode, "tty_write"))
1119 if (!tty || !tty->ops->write ||
1120 (test_bit(TTY_IO_ERROR, &tty->flags)))
1122 /* Short term debug to catch buggy drivers */
1123 if (tty->ops->write_room == NULL)
1124 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1126 ld = tty_ldisc_ref_wait(tty);
1127 if (!ld->ops->write)
1130 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1131 tty_ldisc_deref(ld);
1135 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1136 size_t count, loff_t *ppos)
1138 struct file *p = NULL;
1140 spin_lock(&redirect_lock);
1145 spin_unlock(&redirect_lock);
1149 res = vfs_write(p, buf, count, &p->f_pos);
1153 return tty_write(file, buf, count, ppos);
1156 static char ptychar[] = "pqrstuvwxyzabcde";
1159 * pty_line_name - generate name for a pty
1160 * @driver: the tty driver in use
1161 * @index: the minor number
1162 * @p: output buffer of at least 6 bytes
1164 * Generate a name from a driver reference and write it to the output
1169 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1171 int i = index + driver->name_base;
1172 /* ->name is initialized to "ttyp", but "tty" is expected */
1173 sprintf(p, "%s%c%x",
1174 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1175 ptychar[i >> 4 & 0xf], i & 0xf);
1179 * tty_line_name - generate name for a tty
1180 * @driver: the tty driver in use
1181 * @index: the minor number
1182 * @p: output buffer of at least 7 bytes
1184 * Generate a name from a driver reference and write it to the output
1189 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1191 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1195 * tty_driver_lookup_tty() - find an existing tty, if any
1196 * @driver: the driver for the tty
1197 * @idx: the minor number
1199 * Return the tty, if found or ERR_PTR() otherwise.
1201 * Locking: tty_mutex must be held. If tty is found, the mutex must
1202 * be held until the 'fast-open' is also done. Will change once we
1203 * have refcounting in the driver and per driver locking
1205 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1206 struct inode *inode, int idx)
1208 struct tty_struct *tty;
1210 if (driver->ops->lookup)
1211 return driver->ops->lookup(driver, inode, idx);
1213 tty = driver->ttys[idx];
1218 * tty_init_termios - helper for termios setup
1219 * @tty: the tty to set up
1221 * Initialise the termios structures for this tty. Thus runs under
1222 * the tty_mutex currently so we can be relaxed about ordering.
1225 int tty_init_termios(struct tty_struct *tty)
1227 struct ktermios *tp;
1228 int idx = tty->index;
1230 tp = tty->driver->termios[idx];
1232 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1235 memcpy(tp, &tty->driver->init_termios,
1236 sizeof(struct ktermios));
1237 tty->driver->termios[idx] = tp;
1240 tty->termios_locked = tp + 1;
1242 /* Compatibility until drivers always set this */
1243 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1244 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1247 EXPORT_SYMBOL_GPL(tty_init_termios);
1250 * tty_driver_install_tty() - install a tty entry in the driver
1251 * @driver: the driver for the tty
1254 * Install a tty object into the driver tables. The tty->index field
1255 * will be set by the time this is called. This method is responsible
1256 * for ensuring any need additional structures are allocated and
1259 * Locking: tty_mutex for now
1261 static int tty_driver_install_tty(struct tty_driver *driver,
1262 struct tty_struct *tty)
1264 int idx = tty->index;
1267 if (driver->ops->install) {
1268 ret = driver->ops->install(driver, tty);
1272 if (tty_init_termios(tty) == 0) {
1273 tty_driver_kref_get(driver);
1275 driver->ttys[idx] = tty;
1282 * tty_driver_remove_tty() - remove a tty from the driver tables
1283 * @driver: the driver for the tty
1284 * @idx: the minor number
1286 * Remvoe a tty object from the driver tables. The tty->index field
1287 * will be set by the time this is called.
1289 * Locking: tty_mutex for now
1291 static void tty_driver_remove_tty(struct tty_driver *driver,
1292 struct tty_struct *tty)
1294 if (driver->ops->remove)
1295 driver->ops->remove(driver, tty);
1297 driver->ttys[tty->index] = NULL;
1301 * tty_reopen() - fast re-open of an open tty
1302 * @tty - the tty to open
1304 * Return 0 on success, -errno on error.
1306 * Locking: tty_mutex must be held from the time the tty was found
1307 * till this open completes.
1309 static int tty_reopen(struct tty_struct *tty)
1311 struct tty_driver *driver = tty->driver;
1313 if (test_bit(TTY_CLOSING, &tty->flags))
1316 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1317 driver->subtype == PTY_TYPE_MASTER) {
1319 * special case for PTY masters: only one open permitted,
1320 * and the slave side open count is incremented as well.
1328 tty->driver = driver; /* N.B. why do this every time?? */
1330 mutex_lock(&tty->ldisc_mutex);
1331 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1332 mutex_unlock(&tty->ldisc_mutex);
1338 * tty_init_dev - initialise a tty device
1339 * @driver: tty driver we are opening a device on
1340 * @idx: device index
1341 * @ret_tty: returned tty structure
1342 * @first_ok: ok to open a new device (used by ptmx)
1344 * Prepare a tty device. This may not be a "new" clean device but
1345 * could also be an active device. The pty drivers require special
1346 * handling because of this.
1349 * The function is called under the tty_mutex, which
1350 * protects us from the tty struct or driver itself going away.
1352 * On exit the tty device has the line discipline attached and
1353 * a reference count of 1. If a pair was created for pty/tty use
1354 * and the other was a pty master then it too has a reference count of 1.
1356 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1357 * failed open. The new code protects the open with a mutex, so it's
1358 * really quite straightforward. The mutex locking can probably be
1359 * relaxed for the (most common) case of reopening a tty.
1362 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1365 struct tty_struct *tty;
1368 /* Check if pty master is being opened multiple times */
1369 if (driver->subtype == PTY_TYPE_MASTER &&
1370 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1371 return ERR_PTR(-EIO);
1375 * First time open is complex, especially for PTY devices.
1376 * This code guarantees that either everything succeeds and the
1377 * TTY is ready for operation, or else the table slots are vacated
1378 * and the allocated memory released. (Except that the termios
1379 * and locked termios may be retained.)
1382 if (!try_module_get(driver->owner))
1383 return ERR_PTR(-ENODEV);
1385 tty = alloc_tty_struct();
1388 initialize_tty_struct(tty, driver, idx);
1390 retval = tty_driver_install_tty(driver, tty);
1392 free_tty_struct(tty);
1393 module_put(driver->owner);
1394 return ERR_PTR(retval);
1398 * Structures all installed ... call the ldisc open routines.
1399 * If we fail here just call release_tty to clean up. No need
1400 * to decrement the use counts, as release_tty doesn't care.
1402 retval = tty_ldisc_setup(tty, tty->link);
1404 goto release_mem_out;
1408 module_put(driver->owner);
1409 return ERR_PTR(-ENOMEM);
1411 /* call the tty release_tty routine to clean out this slot */
1413 if (printk_ratelimit())
1414 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1415 "clearing slot %d\n", idx);
1416 release_tty(tty, idx);
1417 return ERR_PTR(retval);
1420 void tty_free_termios(struct tty_struct *tty)
1422 struct ktermios *tp;
1423 int idx = tty->index;
1424 /* Kill this flag and push into drivers for locking etc */
1425 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1426 /* FIXME: Locking on ->termios array */
1428 tty->driver->termios[idx] = NULL;
1432 EXPORT_SYMBOL(tty_free_termios);
1434 void tty_shutdown(struct tty_struct *tty)
1436 tty_driver_remove_tty(tty->driver, tty);
1437 tty_free_termios(tty);
1439 EXPORT_SYMBOL(tty_shutdown);
1442 * release_one_tty - release tty structure memory
1443 * @kref: kref of tty we are obliterating
1445 * Releases memory associated with a tty structure, and clears out the
1446 * driver table slots. This function is called when a device is no longer
1447 * in use. It also gets called when setup of a device fails.
1450 * tty_mutex - sometimes only
1451 * takes the file list lock internally when working on the list
1452 * of ttys that the driver keeps.
1454 * This method gets called from a work queue so that the driver private
1455 * cleanup ops can sleep (needed for USB at least)
1457 static void release_one_tty(struct work_struct *work)
1459 struct tty_struct *tty =
1460 container_of(work, struct tty_struct, hangup_work);
1461 struct tty_driver *driver = tty->driver;
1463 if (tty->ops->cleanup)
1464 tty->ops->cleanup(tty);
1467 tty_driver_kref_put(driver);
1468 module_put(driver->owner);
1470 spin_lock(&tty_files_lock);
1471 list_del_init(&tty->tty_files);
1472 spin_unlock(&tty_files_lock);
1475 put_pid(tty->session);
1476 free_tty_struct(tty);
1479 static void queue_release_one_tty(struct kref *kref)
1481 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1483 if (tty->ops->shutdown)
1484 tty->ops->shutdown(tty);
1488 /* The hangup queue is now free so we can reuse it rather than
1489 waste a chunk of memory for each port */
1490 INIT_WORK(&tty->hangup_work, release_one_tty);
1491 schedule_work(&tty->hangup_work);
1495 * tty_kref_put - release a tty kref
1498 * Release a reference to a tty device and if need be let the kref
1499 * layer destruct the object for us
1502 void tty_kref_put(struct tty_struct *tty)
1505 kref_put(&tty->kref, queue_release_one_tty);
1507 EXPORT_SYMBOL(tty_kref_put);
1510 * release_tty - release tty structure memory
1512 * Release both @tty and a possible linked partner (think pty pair),
1513 * and decrement the refcount of the backing module.
1516 * tty_mutex - sometimes only
1517 * takes the file list lock internally when working on the list
1518 * of ttys that the driver keeps.
1519 * FIXME: should we require tty_mutex is held here ??
1522 static void release_tty(struct tty_struct *tty, int idx)
1524 /* This should always be true but check for the moment */
1525 WARN_ON(tty->index != idx);
1528 tty_kref_put(tty->link);
1533 * tty_release - vfs callback for close
1534 * @inode: inode of tty
1535 * @filp: file pointer for handle to tty
1537 * Called the last time each file handle is closed that references
1538 * this tty. There may however be several such references.
1541 * Takes bkl. See tty_release_dev
1543 * Even releasing the tty structures is a tricky business.. We have
1544 * to be very careful that the structures are all released at the
1545 * same time, as interrupts might otherwise get the wrong pointers.
1547 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1548 * lead to double frees or releasing memory still in use.
1551 int tty_release(struct inode *inode, struct file *filp)
1553 struct tty_struct *tty = file_tty(filp);
1554 struct tty_struct *o_tty;
1555 int pty_master, tty_closing, o_tty_closing, do_sleep;
1560 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1564 check_tty_count(tty, "tty_release_dev");
1566 __tty_fasync(-1, filp, 0);
1569 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1570 tty->driver->subtype == PTY_TYPE_MASTER);
1571 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1574 #ifdef TTY_PARANOIA_CHECK
1575 if (idx < 0 || idx >= tty->driver->num) {
1576 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1577 "free (%s)\n", tty->name);
1582 if (tty != tty->driver->ttys[idx]) {
1584 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1585 "for (%s)\n", idx, tty->name);
1588 if (tty->termios != tty->driver->termios[idx]) {
1590 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1598 #ifdef TTY_DEBUG_HANGUP
1599 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1600 tty_name(tty, buf), tty->count);
1603 #ifdef TTY_PARANOIA_CHECK
1604 if (tty->driver->other &&
1605 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1606 if (o_tty != tty->driver->other->ttys[idx]) {
1608 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1609 "not o_tty for (%s)\n",
1613 if (o_tty->termios != tty->driver->other->termios[idx]) {
1615 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1616 "not o_termios for (%s)\n",
1620 if (o_tty->link != tty) {
1622 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1627 if (tty->ops->close)
1628 tty->ops->close(tty, filp);
1632 * Sanity check: if tty->count is going to zero, there shouldn't be
1633 * any waiters on tty->read_wait or tty->write_wait. We test the
1634 * wait queues and kick everyone out _before_ actually starting to
1635 * close. This ensures that we won't block while releasing the tty
1638 * The test for the o_tty closing is necessary, since the master and
1639 * slave sides may close in any order. If the slave side closes out
1640 * first, its count will be one, since the master side holds an open.
1641 * Thus this test wouldn't be triggered at the time the slave closes,
1644 * Note that it's possible for the tty to be opened again while we're
1645 * flushing out waiters. By recalculating the closing flags before
1646 * each iteration we avoid any problems.
1649 /* Guard against races with tty->count changes elsewhere and
1650 opens on /dev/tty */
1652 mutex_lock(&tty_mutex);
1654 tty_closing = tty->count <= 1;
1655 o_tty_closing = o_tty &&
1656 (o_tty->count <= (pty_master ? 1 : 0));
1660 if (waitqueue_active(&tty->read_wait)) {
1661 wake_up_poll(&tty->read_wait, POLLIN);
1664 if (waitqueue_active(&tty->write_wait)) {
1665 wake_up_poll(&tty->write_wait, POLLOUT);
1669 if (o_tty_closing) {
1670 if (waitqueue_active(&o_tty->read_wait)) {
1671 wake_up_poll(&o_tty->read_wait, POLLIN);
1674 if (waitqueue_active(&o_tty->write_wait)) {
1675 wake_up_poll(&o_tty->write_wait, POLLOUT);
1682 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1683 "active!\n", tty_name(tty, buf));
1685 mutex_unlock(&tty_mutex);
1690 * The closing flags are now consistent with the open counts on
1691 * both sides, and we've completed the last operation that could
1692 * block, so it's safe to proceed with closing.
1695 if (--o_tty->count < 0) {
1696 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1698 o_tty->count, tty_name(o_tty, buf));
1702 if (--tty->count < 0) {
1703 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1704 tty->count, tty_name(tty, buf));
1709 * We've decremented tty->count, so we need to remove this file
1710 * descriptor off the tty->tty_files list; this serves two
1712 * - check_tty_count sees the correct number of file descriptors
1713 * associated with this tty.
1714 * - do_tty_hangup no longer sees this file descriptor as
1715 * something that needs to be handled for hangups.
1720 * Perform some housekeeping before deciding whether to return.
1722 * Set the TTY_CLOSING flag if this was the last open. In the
1723 * case of a pty we may have to wait around for the other side
1724 * to close, and TTY_CLOSING makes sure we can't be reopened.
1727 set_bit(TTY_CLOSING, &tty->flags);
1729 set_bit(TTY_CLOSING, &o_tty->flags);
1732 * If _either_ side is closing, make sure there aren't any
1733 * processes that still think tty or o_tty is their controlling
1736 if (tty_closing || o_tty_closing) {
1737 read_lock(&tasklist_lock);
1738 session_clear_tty(tty->session);
1740 session_clear_tty(o_tty->session);
1741 read_unlock(&tasklist_lock);
1744 mutex_unlock(&tty_mutex);
1746 /* check whether both sides are closing ... */
1747 if (!tty_closing || (o_tty && !o_tty_closing)) {
1752 #ifdef TTY_DEBUG_HANGUP
1753 printk(KERN_DEBUG "freeing tty structure...");
1756 * Ask the line discipline code to release its structures
1758 tty_ldisc_release(tty, o_tty);
1760 * The release_tty function takes care of the details of clearing
1761 * the slots and preserving the termios structure.
1763 release_tty(tty, idx);
1765 /* Make this pty number available for reallocation */
1767 devpts_kill_index(inode, idx);
1773 * tty_open - open a tty device
1774 * @inode: inode of device file
1775 * @filp: file pointer to tty
1777 * tty_open and tty_release keep up the tty count that contains the
1778 * number of opens done on a tty. We cannot use the inode-count, as
1779 * different inodes might point to the same tty.
1781 * Open-counting is needed for pty masters, as well as for keeping
1782 * track of serial lines: DTR is dropped when the last close happens.
1783 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1785 * The termios state of a pty is reset on first open so that
1786 * settings don't persist across reuse.
1788 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1789 * tty->count should protect the rest.
1790 * ->siglock protects ->signal/->sighand
1793 static int tty_open(struct inode *inode, struct file *filp)
1795 struct tty_struct *tty = NULL;
1797 struct tty_driver *driver;
1799 dev_t device = inode->i_rdev;
1800 unsigned saved_flags = filp->f_flags;
1802 nonseekable_open(inode, filp);
1805 noctty = filp->f_flags & O_NOCTTY;
1809 mutex_lock(&tty_mutex);
1812 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1813 tty = get_current_tty();
1816 mutex_unlock(&tty_mutex);
1819 driver = tty_driver_kref_get(tty->driver);
1821 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1823 /* FIXME: Should we take a driver reference ? */
1828 if (device == MKDEV(TTY_MAJOR, 0)) {
1829 extern struct tty_driver *console_driver;
1830 driver = tty_driver_kref_get(console_driver);
1836 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1837 struct tty_driver *console_driver = console_device(&index);
1838 if (console_driver) {
1839 driver = tty_driver_kref_get(console_driver);
1841 /* Don't let /dev/console block */
1842 filp->f_flags |= O_NONBLOCK;
1848 mutex_unlock(&tty_mutex);
1852 driver = get_tty_driver(device, &index);
1855 mutex_unlock(&tty_mutex);
1860 /* check whether we're reopening an existing tty */
1861 tty = tty_driver_lookup_tty(driver, inode, index);
1865 mutex_unlock(&tty_mutex);
1866 return PTR_ERR(tty);
1871 retval = tty_reopen(tty);
1873 tty = ERR_PTR(retval);
1875 tty = tty_init_dev(driver, index, 0);
1877 mutex_unlock(&tty_mutex);
1878 tty_driver_kref_put(driver);
1881 return PTR_ERR(tty);
1884 retval = tty_add_file(tty, filp);
1890 check_tty_count(tty, "tty_open");
1891 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1892 tty->driver->subtype == PTY_TYPE_MASTER)
1894 #ifdef TTY_DEBUG_HANGUP
1895 printk(KERN_DEBUG "opening %s...", tty->name);
1899 retval = tty->ops->open(tty, filp);
1903 filp->f_flags = saved_flags;
1905 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1906 !capable(CAP_SYS_ADMIN))
1910 #ifdef TTY_DEBUG_HANGUP
1911 printk(KERN_DEBUG "error %d in opening %s...", retval,
1914 tty_unlock(); /* need to call tty_release without BTM */
1915 tty_release(inode, filp);
1916 if (retval != -ERESTARTSYS)
1919 if (signal_pending(current))
1924 * Need to reset f_op in case a hangup happened.
1927 if (filp->f_op == &hung_up_tty_fops)
1928 filp->f_op = &tty_fops;
1935 mutex_lock(&tty_mutex);
1937 spin_lock_irq(¤t->sighand->siglock);
1939 current->signal->leader &&
1940 !current->signal->tty &&
1941 tty->session == NULL)
1942 __proc_set_tty(current, tty);
1943 spin_unlock_irq(¤t->sighand->siglock);
1945 mutex_unlock(&tty_mutex);
1952 * tty_poll - check tty status
1953 * @filp: file being polled
1954 * @wait: poll wait structures to update
1956 * Call the line discipline polling method to obtain the poll
1957 * status of the device.
1959 * Locking: locks called line discipline but ldisc poll method
1960 * may be re-entered freely by other callers.
1963 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1965 struct tty_struct *tty = file_tty(filp);
1966 struct tty_ldisc *ld;
1969 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1972 ld = tty_ldisc_ref_wait(tty);
1974 ret = (ld->ops->poll)(tty, filp, wait);
1975 tty_ldisc_deref(ld);
1979 static int __tty_fasync(int fd, struct file *filp, int on)
1981 struct tty_struct *tty = file_tty(filp);
1982 unsigned long flags;
1985 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1988 retval = fasync_helper(fd, filp, on, &tty->fasync);
1995 if (!waitqueue_active(&tty->read_wait))
1996 tty->minimum_to_wake = 1;
1997 spin_lock_irqsave(&tty->ctrl_lock, flags);
2000 type = PIDTYPE_PGID;
2002 pid = task_pid(current);
2006 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2007 retval = __f_setown(filp, pid, type, 0);
2012 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2013 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2020 static int tty_fasync(int fd, struct file *filp, int on)
2024 retval = __tty_fasync(fd, filp, on);
2030 * tiocsti - fake input character
2031 * @tty: tty to fake input into
2032 * @p: pointer to character
2034 * Fake input to a tty device. Does the necessary locking and
2037 * FIXME: does not honour flow control ??
2040 * Called functions take tty_ldisc_lock
2041 * current->signal->tty check is safe without locks
2043 * FIXME: may race normal receive processing
2046 static int tiocsti(struct tty_struct *tty, char __user *p)
2049 struct tty_ldisc *ld;
2051 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2053 if (get_user(ch, p))
2055 tty_audit_tiocsti(tty, ch);
2056 ld = tty_ldisc_ref_wait(tty);
2057 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2058 tty_ldisc_deref(ld);
2063 * tiocgwinsz - implement window query ioctl
2065 * @arg: user buffer for result
2067 * Copies the kernel idea of the window size into the user buffer.
2069 * Locking: tty->termios_mutex is taken to ensure the winsize data
2073 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2077 mutex_lock(&tty->termios_mutex);
2078 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2079 mutex_unlock(&tty->termios_mutex);
2081 return err ? -EFAULT: 0;
2085 * tty_do_resize - resize event
2086 * @tty: tty being resized
2087 * @rows: rows (character)
2088 * @cols: cols (character)
2090 * Update the termios variables and send the necessary signals to
2091 * peform a terminal resize correctly
2094 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2097 unsigned long flags;
2100 mutex_lock(&tty->termios_mutex);
2101 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2103 /* Get the PID values and reference them so we can
2104 avoid holding the tty ctrl lock while sending signals */
2105 spin_lock_irqsave(&tty->ctrl_lock, flags);
2106 pgrp = get_pid(tty->pgrp);
2107 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2110 kill_pgrp(pgrp, SIGWINCH, 1);
2115 mutex_unlock(&tty->termios_mutex);
2120 * tiocswinsz - implement window size set ioctl
2121 * @tty; tty side of tty
2122 * @arg: user buffer for result
2124 * Copies the user idea of the window size to the kernel. Traditionally
2125 * this is just advisory information but for the Linux console it
2126 * actually has driver level meaning and triggers a VC resize.
2129 * Driver dependant. The default do_resize method takes the
2130 * tty termios mutex and ctrl_lock. The console takes its own lock
2131 * then calls into the default method.
2134 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2136 struct winsize tmp_ws;
2137 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2140 if (tty->ops->resize)
2141 return tty->ops->resize(tty, &tmp_ws);
2143 return tty_do_resize(tty, &tmp_ws);
2147 * tioccons - allow admin to move logical console
2148 * @file: the file to become console
2150 * Allow the adminstrator to move the redirected console device
2152 * Locking: uses redirect_lock to guard the redirect information
2155 static int tioccons(struct file *file)
2157 if (!capable(CAP_SYS_ADMIN))
2159 if (file->f_op->write == redirected_tty_write) {
2161 spin_lock(&redirect_lock);
2164 spin_unlock(&redirect_lock);
2169 spin_lock(&redirect_lock);
2171 spin_unlock(&redirect_lock);
2176 spin_unlock(&redirect_lock);
2181 * fionbio - non blocking ioctl
2182 * @file: file to set blocking value
2183 * @p: user parameter
2185 * Historical tty interfaces had a blocking control ioctl before
2186 * the generic functionality existed. This piece of history is preserved
2187 * in the expected tty API of posix OS's.
2189 * Locking: none, the open file handle ensures it won't go away.
2192 static int fionbio(struct file *file, int __user *p)
2196 if (get_user(nonblock, p))
2199 spin_lock(&file->f_lock);
2201 file->f_flags |= O_NONBLOCK;
2203 file->f_flags &= ~O_NONBLOCK;
2204 spin_unlock(&file->f_lock);
2209 * tiocsctty - set controlling tty
2210 * @tty: tty structure
2211 * @arg: user argument
2213 * This ioctl is used to manage job control. It permits a session
2214 * leader to set this tty as the controlling tty for the session.
2217 * Takes tty_mutex() to protect tty instance
2218 * Takes tasklist_lock internally to walk sessions
2219 * Takes ->siglock() when updating signal->tty
2222 static int tiocsctty(struct tty_struct *tty, int arg)
2225 if (current->signal->leader && (task_session(current) == tty->session))
2228 mutex_lock(&tty_mutex);
2230 * The process must be a session leader and
2231 * not have a controlling tty already.
2233 if (!current->signal->leader || current->signal->tty) {
2240 * This tty is already the controlling
2241 * tty for another session group!
2243 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2247 read_lock(&tasklist_lock);
2248 session_clear_tty(tty->session);
2249 read_unlock(&tasklist_lock);
2255 proc_set_tty(current, tty);
2257 mutex_unlock(&tty_mutex);
2262 * tty_get_pgrp - return a ref counted pgrp pid
2265 * Returns a refcounted instance of the pid struct for the process
2266 * group controlling the tty.
2269 struct pid *tty_get_pgrp(struct tty_struct *tty)
2271 unsigned long flags;
2274 spin_lock_irqsave(&tty->ctrl_lock, flags);
2275 pgrp = get_pid(tty->pgrp);
2276 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2280 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2283 * tiocgpgrp - get process group
2284 * @tty: tty passed by user
2285 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2288 * Obtain the process group of the tty. If there is no process group
2291 * Locking: none. Reference to current->signal->tty is safe.
2294 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2299 * (tty == real_tty) is a cheap way of
2300 * testing if the tty is NOT a master pty.
2302 if (tty == real_tty && current->signal->tty != real_tty)
2304 pid = tty_get_pgrp(real_tty);
2305 ret = put_user(pid_vnr(pid), p);
2311 * tiocspgrp - attempt to set process group
2312 * @tty: tty passed by user
2313 * @real_tty: tty side device matching tty passed by user
2316 * Set the process group of the tty to the session passed. Only
2317 * permitted where the tty session is our session.
2319 * Locking: RCU, ctrl lock
2322 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2326 int retval = tty_check_change(real_tty);
2327 unsigned long flags;
2333 if (!current->signal->tty ||
2334 (current->signal->tty != real_tty) ||
2335 (real_tty->session != task_session(current)))
2337 if (get_user(pgrp_nr, p))
2342 pgrp = find_vpid(pgrp_nr);
2347 if (session_of_pgrp(pgrp) != task_session(current))
2350 spin_lock_irqsave(&tty->ctrl_lock, flags);
2351 put_pid(real_tty->pgrp);
2352 real_tty->pgrp = get_pid(pgrp);
2353 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2360 * tiocgsid - get session id
2361 * @tty: tty passed by user
2362 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2363 * @p: pointer to returned session id
2365 * Obtain the session id of the tty. If there is no session
2368 * Locking: none. Reference to current->signal->tty is safe.
2371 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2374 * (tty == real_tty) is a cheap way of
2375 * testing if the tty is NOT a master pty.
2377 if (tty == real_tty && current->signal->tty != real_tty)
2379 if (!real_tty->session)
2381 return put_user(pid_vnr(real_tty->session), p);
2385 * tiocsetd - set line discipline
2387 * @p: pointer to user data
2389 * Set the line discipline according to user request.
2391 * Locking: see tty_set_ldisc, this function is just a helper
2394 static int tiocsetd(struct tty_struct *tty, int __user *p)
2399 if (get_user(ldisc, p))
2402 ret = tty_set_ldisc(tty, ldisc);
2408 * send_break - performed time break
2409 * @tty: device to break on
2410 * @duration: timeout in mS
2412 * Perform a timed break on hardware that lacks its own driver level
2413 * timed break functionality.
2416 * atomic_write_lock serializes
2420 static int send_break(struct tty_struct *tty, unsigned int duration)
2424 if (tty->ops->break_ctl == NULL)
2427 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2428 retval = tty->ops->break_ctl(tty, duration);
2430 /* Do the work ourselves */
2431 if (tty_write_lock(tty, 0) < 0)
2433 retval = tty->ops->break_ctl(tty, -1);
2436 if (!signal_pending(current))
2437 msleep_interruptible(duration);
2438 retval = tty->ops->break_ctl(tty, 0);
2440 tty_write_unlock(tty);
2441 if (signal_pending(current))
2448 * tty_tiocmget - get modem status
2450 * @file: user file pointer
2451 * @p: pointer to result
2453 * Obtain the modem status bits from the tty driver if the feature
2454 * is supported. Return -EINVAL if it is not available.
2456 * Locking: none (up to the driver)
2459 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2461 int retval = -EINVAL;
2463 if (tty->ops->tiocmget) {
2464 retval = tty->ops->tiocmget(tty, file);
2467 retval = put_user(retval, p);
2473 * tty_tiocmset - set modem status
2475 * @file: user file pointer
2476 * @cmd: command - clear bits, set bits or set all
2477 * @p: pointer to desired bits
2479 * Set the modem status bits from the tty driver if the feature
2480 * is supported. Return -EINVAL if it is not available.
2482 * Locking: none (up to the driver)
2485 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2489 unsigned int set, clear, val;
2491 if (tty->ops->tiocmset == NULL)
2494 retval = get_user(val, p);
2510 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2511 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2512 return tty->ops->tiocmset(tty, file, set, clear);
2515 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2517 int retval = -EINVAL;
2518 struct serial_icounter_struct icount;
2519 memset(&icount, 0, sizeof(icount));
2520 if (tty->ops->get_icount)
2521 retval = tty->ops->get_icount(tty, &icount);
2524 if (copy_to_user(arg, &icount, sizeof(icount)))
2529 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2531 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2532 tty->driver->subtype == PTY_TYPE_MASTER)
2536 EXPORT_SYMBOL(tty_pair_get_tty);
2538 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2540 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2541 tty->driver->subtype == PTY_TYPE_MASTER)
2545 EXPORT_SYMBOL(tty_pair_get_pty);
2548 * Split this up, as gcc can choke on it otherwise..
2550 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2552 struct tty_struct *tty = file_tty(file);
2553 struct tty_struct *real_tty;
2554 void __user *p = (void __user *)arg;
2556 struct tty_ldisc *ld;
2557 struct inode *inode = file->f_dentry->d_inode;
2559 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2562 real_tty = tty_pair_get_tty(tty);
2565 * Factor out some common prep work
2573 retval = tty_check_change(tty);
2576 if (cmd != TIOCCBRK) {
2577 tty_wait_until_sent(tty, 0);
2578 if (signal_pending(current))
2589 return tiocsti(tty, p);
2591 return tiocgwinsz(real_tty, p);
2593 return tiocswinsz(real_tty, p);
2595 return real_tty != tty ? -EINVAL : tioccons(file);
2597 return fionbio(file, p);
2599 set_bit(TTY_EXCLUSIVE, &tty->flags);
2602 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2605 if (current->signal->tty != tty)
2610 return tiocsctty(tty, arg);
2612 return tiocgpgrp(tty, real_tty, p);
2614 return tiocspgrp(tty, real_tty, p);
2616 return tiocgsid(tty, real_tty, p);
2618 return put_user(tty->ldisc->ops->num, (int __user *)p);
2620 return tiocsetd(tty, p);
2624 case TIOCSBRK: /* Turn break on, unconditionally */
2625 if (tty->ops->break_ctl)
2626 return tty->ops->break_ctl(tty, -1);
2628 case TIOCCBRK: /* Turn break off, unconditionally */
2629 if (tty->ops->break_ctl)
2630 return tty->ops->break_ctl(tty, 0);
2632 case TCSBRK: /* SVID version: non-zero arg --> no break */
2633 /* non-zero arg means wait for all output data
2634 * to be sent (performed above) but don't send break.
2635 * This is used by the tcdrain() termios function.
2638 return send_break(tty, 250);
2640 case TCSBRKP: /* support for POSIX tcsendbreak() */
2641 return send_break(tty, arg ? arg*100 : 250);
2644 return tty_tiocmget(tty, file, p);
2648 return tty_tiocmset(tty, file, cmd, p);
2650 retval = tty_tiocgicount(tty, p);
2651 /* For the moment allow fall through to the old method */
2652 if (retval != -EINVAL)
2659 /* flush tty buffer and allow ldisc to process ioctl */
2660 tty_buffer_flush(tty);
2665 if (tty->ops->ioctl) {
2666 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2667 if (retval != -ENOIOCTLCMD)
2670 ld = tty_ldisc_ref_wait(tty);
2672 if (ld->ops->ioctl) {
2673 retval = ld->ops->ioctl(tty, file, cmd, arg);
2674 if (retval == -ENOIOCTLCMD)
2677 tty_ldisc_deref(ld);
2681 #ifdef CONFIG_COMPAT
2682 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2685 struct inode *inode = file->f_dentry->d_inode;
2686 struct tty_struct *tty = file_tty(file);
2687 struct tty_ldisc *ld;
2688 int retval = -ENOIOCTLCMD;
2690 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2693 if (tty->ops->compat_ioctl) {
2694 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2695 if (retval != -ENOIOCTLCMD)
2699 ld = tty_ldisc_ref_wait(tty);
2700 if (ld->ops->compat_ioctl)
2701 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2702 tty_ldisc_deref(ld);
2709 * This implements the "Secure Attention Key" --- the idea is to
2710 * prevent trojan horses by killing all processes associated with this
2711 * tty when the user hits the "Secure Attention Key". Required for
2712 * super-paranoid applications --- see the Orange Book for more details.
2714 * This code could be nicer; ideally it should send a HUP, wait a few
2715 * seconds, then send a INT, and then a KILL signal. But you then
2716 * have to coordinate with the init process, since all processes associated
2717 * with the current tty must be dead before the new getty is allowed
2720 * Now, if it would be correct ;-/ The current code has a nasty hole -
2721 * it doesn't catch files in flight. We may send the descriptor to ourselves
2722 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2724 * Nasty bug: do_SAK is being called in interrupt context. This can
2725 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2727 void __do_SAK(struct tty_struct *tty)
2732 struct task_struct *g, *p;
2733 struct pid *session;
2736 struct fdtable *fdt;
2740 session = tty->session;
2742 tty_ldisc_flush(tty);
2744 tty_driver_flush_buffer(tty);
2746 read_lock(&tasklist_lock);
2747 /* Kill the entire session */
2748 do_each_pid_task(session, PIDTYPE_SID, p) {
2749 printk(KERN_NOTICE "SAK: killed process %d"
2750 " (%s): task_session(p)==tty->session\n",
2751 task_pid_nr(p), p->comm);
2752 send_sig(SIGKILL, p, 1);
2753 } while_each_pid_task(session, PIDTYPE_SID, p);
2754 /* Now kill any processes that happen to have the
2757 do_each_thread(g, p) {
2758 if (p->signal->tty == tty) {
2759 printk(KERN_NOTICE "SAK: killed process %d"
2760 " (%s): task_session(p)==tty->session\n",
2761 task_pid_nr(p), p->comm);
2762 send_sig(SIGKILL, p, 1);
2768 * We don't take a ref to the file, so we must
2769 * hold ->file_lock instead.
2771 spin_lock(&p->files->file_lock);
2772 fdt = files_fdtable(p->files);
2773 for (i = 0; i < fdt->max_fds; i++) {
2774 filp = fcheck_files(p->files, i);
2777 if (filp->f_op->read == tty_read &&
2778 file_tty(filp) == tty) {
2779 printk(KERN_NOTICE "SAK: killed process %d"
2780 " (%s): fd#%d opened to the tty\n",
2781 task_pid_nr(p), p->comm, i);
2782 force_sig(SIGKILL, p);
2786 spin_unlock(&p->files->file_lock);
2789 } while_each_thread(g, p);
2790 read_unlock(&tasklist_lock);
2794 static void do_SAK_work(struct work_struct *work)
2796 struct tty_struct *tty =
2797 container_of(work, struct tty_struct, SAK_work);
2802 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2803 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2804 * the values which we write to it will be identical to the values which it
2805 * already has. --akpm
2807 void do_SAK(struct tty_struct *tty)
2811 schedule_work(&tty->SAK_work);
2814 EXPORT_SYMBOL(do_SAK);
2816 static int dev_match_devt(struct device *dev, void *data)
2819 return dev->devt == *devt;
2822 /* Must put_device() after it's unused! */
2823 static struct device *tty_get_device(struct tty_struct *tty)
2825 dev_t devt = tty_devnum(tty);
2826 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2831 * initialize_tty_struct
2832 * @tty: tty to initialize
2834 * This subroutine initializes a tty structure that has been newly
2837 * Locking: none - tty in question must not be exposed at this point
2840 void initialize_tty_struct(struct tty_struct *tty,
2841 struct tty_driver *driver, int idx)
2843 memset(tty, 0, sizeof(struct tty_struct));
2844 kref_init(&tty->kref);
2845 tty->magic = TTY_MAGIC;
2846 tty_ldisc_init(tty);
2847 tty->session = NULL;
2849 tty->overrun_time = jiffies;
2850 tty->buf.head = tty->buf.tail = NULL;
2851 tty_buffer_init(tty);
2852 mutex_init(&tty->termios_mutex);
2853 mutex_init(&tty->ldisc_mutex);
2854 init_waitqueue_head(&tty->write_wait);
2855 init_waitqueue_head(&tty->read_wait);
2856 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2857 mutex_init(&tty->atomic_read_lock);
2858 mutex_init(&tty->atomic_write_lock);
2859 mutex_init(&tty->output_lock);
2860 mutex_init(&tty->echo_lock);
2861 spin_lock_init(&tty->read_lock);
2862 spin_lock_init(&tty->ctrl_lock);
2863 INIT_LIST_HEAD(&tty->tty_files);
2864 INIT_WORK(&tty->SAK_work, do_SAK_work);
2866 tty->driver = driver;
2867 tty->ops = driver->ops;
2869 tty_line_name(driver, idx, tty->name);
2870 tty->dev = tty_get_device(tty);
2874 * tty_put_char - write one character to a tty
2878 * Write one byte to the tty using the provided put_char method
2879 * if present. Returns the number of characters successfully output.
2881 * Note: the specific put_char operation in the driver layer may go
2882 * away soon. Don't call it directly, use this method
2885 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2887 if (tty->ops->put_char)
2888 return tty->ops->put_char(tty, ch);
2889 return tty->ops->write(tty, &ch, 1);
2891 EXPORT_SYMBOL_GPL(tty_put_char);
2893 struct class *tty_class;
2896 * tty_register_device - register a tty device
2897 * @driver: the tty driver that describes the tty device
2898 * @index: the index in the tty driver for this tty device
2899 * @device: a struct device that is associated with this tty device.
2900 * This field is optional, if there is no known struct device
2901 * for this tty device it can be set to NULL safely.
2903 * Returns a pointer to the struct device for this tty device
2904 * (or ERR_PTR(-EFOO) on error).
2906 * This call is required to be made to register an individual tty device
2907 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2908 * that bit is not set, this function should not be called by a tty
2914 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2915 struct device *device)
2918 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2920 if (index >= driver->num) {
2921 printk(KERN_ERR "Attempt to register invalid tty line number "
2923 return ERR_PTR(-EINVAL);
2926 if (driver->type == TTY_DRIVER_TYPE_PTY)
2927 pty_line_name(driver, index, name);
2929 tty_line_name(driver, index, name);
2931 return device_create(tty_class, device, dev, NULL, name);
2933 EXPORT_SYMBOL(tty_register_device);
2936 * tty_unregister_device - unregister a tty device
2937 * @driver: the tty driver that describes the tty device
2938 * @index: the index in the tty driver for this tty device
2940 * If a tty device is registered with a call to tty_register_device() then
2941 * this function must be called when the tty device is gone.
2946 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2948 device_destroy(tty_class,
2949 MKDEV(driver->major, driver->minor_start) + index);
2951 EXPORT_SYMBOL(tty_unregister_device);
2953 struct tty_driver *alloc_tty_driver(int lines)
2955 struct tty_driver *driver;
2957 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2959 kref_init(&driver->kref);
2960 driver->magic = TTY_DRIVER_MAGIC;
2961 driver->num = lines;
2962 /* later we'll move allocation of tables here */
2966 EXPORT_SYMBOL(alloc_tty_driver);
2968 static void destruct_tty_driver(struct kref *kref)
2970 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2972 struct ktermios *tp;
2975 if (driver->flags & TTY_DRIVER_INSTALLED) {
2977 * Free the termios and termios_locked structures because
2978 * we don't want to get memory leaks when modular tty
2979 * drivers are removed from the kernel.
2981 for (i = 0; i < driver->num; i++) {
2982 tp = driver->termios[i];
2984 driver->termios[i] = NULL;
2987 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2988 tty_unregister_device(driver, i);
2991 proc_tty_unregister_driver(driver);
2992 driver->ttys = NULL;
2993 driver->termios = NULL;
2995 cdev_del(&driver->cdev);
3000 void tty_driver_kref_put(struct tty_driver *driver)
3002 kref_put(&driver->kref, destruct_tty_driver);
3004 EXPORT_SYMBOL(tty_driver_kref_put);
3006 void tty_set_operations(struct tty_driver *driver,
3007 const struct tty_operations *op)
3011 EXPORT_SYMBOL(tty_set_operations);
3013 void put_tty_driver(struct tty_driver *d)
3015 tty_driver_kref_put(d);
3017 EXPORT_SYMBOL(put_tty_driver);
3020 * Called by a tty driver to register itself.
3022 int tty_register_driver(struct tty_driver *driver)
3030 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3031 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3036 if (!driver->major) {
3037 error = alloc_chrdev_region(&dev, driver->minor_start,
3038 driver->num, driver->name);
3040 driver->major = MAJOR(dev);
3041 driver->minor_start = MINOR(dev);
3044 dev = MKDEV(driver->major, driver->minor_start);
3045 error = register_chrdev_region(dev, driver->num, driver->name);
3053 driver->ttys = (struct tty_struct **)p;
3054 driver->termios = (struct ktermios **)(p + driver->num);
3056 driver->ttys = NULL;
3057 driver->termios = NULL;
3060 cdev_init(&driver->cdev, &tty_fops);
3061 driver->cdev.owner = driver->owner;
3062 error = cdev_add(&driver->cdev, dev, driver->num);
3064 unregister_chrdev_region(dev, driver->num);
3065 driver->ttys = NULL;
3066 driver->termios = NULL;
3071 mutex_lock(&tty_mutex);
3072 list_add(&driver->tty_drivers, &tty_drivers);
3073 mutex_unlock(&tty_mutex);
3075 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3076 for (i = 0; i < driver->num; i++) {
3077 d = tty_register_device(driver, i, NULL);
3084 proc_tty_register_driver(driver);
3085 driver->flags |= TTY_DRIVER_INSTALLED;
3089 for (i--; i >= 0; i--)
3090 tty_unregister_device(driver, i);
3092 mutex_lock(&tty_mutex);
3093 list_del(&driver->tty_drivers);
3094 mutex_unlock(&tty_mutex);
3096 unregister_chrdev_region(dev, driver->num);
3097 driver->ttys = NULL;
3098 driver->termios = NULL;
3103 EXPORT_SYMBOL(tty_register_driver);
3106 * Called by a tty driver to unregister itself.
3108 int tty_unregister_driver(struct tty_driver *driver)
3112 if (driver->refcount)
3115 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3117 mutex_lock(&tty_mutex);
3118 list_del(&driver->tty_drivers);
3119 mutex_unlock(&tty_mutex);
3123 EXPORT_SYMBOL(tty_unregister_driver);
3125 dev_t tty_devnum(struct tty_struct *tty)
3127 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3129 EXPORT_SYMBOL(tty_devnum);
3131 void proc_clear_tty(struct task_struct *p)
3133 unsigned long flags;
3134 struct tty_struct *tty;
3135 spin_lock_irqsave(&p->sighand->siglock, flags);
3136 tty = p->signal->tty;
3137 p->signal->tty = NULL;
3138 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3142 /* Called under the sighand lock */
3144 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3147 unsigned long flags;
3148 /* We should not have a session or pgrp to put here but.... */
3149 spin_lock_irqsave(&tty->ctrl_lock, flags);
3150 put_pid(tty->session);
3152 tty->pgrp = get_pid(task_pgrp(tsk));
3153 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3154 tty->session = get_pid(task_session(tsk));
3155 if (tsk->signal->tty) {
3156 printk(KERN_DEBUG "tty not NULL!!\n");
3157 tty_kref_put(tsk->signal->tty);
3160 put_pid(tsk->signal->tty_old_pgrp);
3161 tsk->signal->tty = tty_kref_get(tty);
3162 tsk->signal->tty_old_pgrp = NULL;
3165 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3167 spin_lock_irq(&tsk->sighand->siglock);
3168 __proc_set_tty(tsk, tty);
3169 spin_unlock_irq(&tsk->sighand->siglock);
3172 struct tty_struct *get_current_tty(void)
3174 struct tty_struct *tty;
3175 unsigned long flags;
3177 spin_lock_irqsave(¤t->sighand->siglock, flags);
3178 tty = tty_kref_get(current->signal->tty);
3179 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3182 EXPORT_SYMBOL_GPL(get_current_tty);
3184 void tty_default_fops(struct file_operations *fops)
3190 * Initialize the console device. This is called *early*, so
3191 * we can't necessarily depend on lots of kernel help here.
3192 * Just do some early initializations, and do the complex setup
3195 void __init console_init(void)
3199 /* Setup the default TTY line discipline. */
3203 * set up the console device so that later boot sequences can
3204 * inform about problems etc..
3206 call = __con_initcall_start;
3207 while (call < __con_initcall_end) {
3213 static char *tty_devnode(struct device *dev, mode_t *mode)
3217 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3218 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3223 static int __init tty_class_init(void)
3225 tty_class = class_create(THIS_MODULE, "tty");
3226 if (IS_ERR(tty_class))
3227 return PTR_ERR(tty_class);
3228 tty_class->devnode = tty_devnode;
3232 postcore_initcall(tty_class_init);
3234 /* 3/2004 jmc: why do these devices exist? */
3236 static struct cdev tty_cdev, console_cdev;
3239 * Ok, now we can initialize the rest of the tty devices and can count
3240 * on memory allocations, interrupts etc..
3242 int __init tty_init(void)
3244 cdev_init(&tty_cdev, &tty_fops);
3245 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3246 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3247 panic("Couldn't register /dev/tty driver\n");
3248 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3251 cdev_init(&console_cdev, &console_fops);
3252 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3253 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3254 panic("Couldn't register /dev/console driver\n");
3255 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3259 vty_init(&console_fops);