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 /* Spinlock to protect the tty->tty_files list */
140 DEFINE_SPINLOCK(tty_files_lock);
142 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
143 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
144 ssize_t redirected_tty_write(struct file *, const char __user *,
146 static unsigned int tty_poll(struct file *, poll_table *);
147 static int tty_open(struct inode *, struct file *);
148 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 #define tty_compat_ioctl NULL
155 static int __tty_fasync(int fd, struct file *filp, int on);
156 static int tty_fasync(int fd, struct file *filp, int on);
157 static void release_tty(struct tty_struct *tty, int idx);
158 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
159 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
162 * alloc_tty_struct - allocate a tty object
164 * Return a new empty tty structure. The data fields have not
165 * been initialized in any way but has been zeroed
170 struct tty_struct *alloc_tty_struct(void)
172 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
176 * free_tty_struct - free a disused tty
177 * @tty: tty struct to free
179 * Free the write buffers, tty queue and tty memory itself.
181 * Locking: none. Must be called after tty is definitely unused
184 void free_tty_struct(struct tty_struct *tty)
186 kfree(tty->write_buf);
187 tty_buffer_free_all(tty);
191 static inline struct tty_struct *file_tty(struct file *file)
193 return ((struct tty_file_private *)file->private_data)->tty;
196 /* Associate a new file with the tty structure */
197 void tty_add_file(struct tty_struct *tty, struct file *file)
199 struct tty_file_private *priv;
201 /* XXX: must implement proper error handling in callers */
202 priv = kmalloc(sizeof(*priv), GFP_KERNEL|__GFP_NOFAIL);
206 file->private_data = priv;
208 spin_lock(&tty_files_lock);
209 list_add(&priv->list, &tty->tty_files);
210 spin_unlock(&tty_files_lock);
213 /* Delete file from its tty */
214 void tty_del_file(struct file *file)
216 struct tty_file_private *priv = file->private_data;
218 spin_lock(&tty_files_lock);
219 list_del(&priv->list);
220 spin_unlock(&tty_files_lock);
221 file->private_data = NULL;
226 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
229 * tty_name - return tty naming
230 * @tty: tty structure
231 * @buf: buffer for output
233 * Convert a tty structure into a name. The name reflects the kernel
234 * naming policy and if udev is in use may not reflect user space
239 char *tty_name(struct tty_struct *tty, char *buf)
241 if (!tty) /* Hmm. NULL pointer. That's fun. */
242 strcpy(buf, "NULL tty");
244 strcpy(buf, tty->name);
248 EXPORT_SYMBOL(tty_name);
250 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
253 #ifdef TTY_PARANOIA_CHECK
256 "null TTY for (%d:%d) in %s\n",
257 imajor(inode), iminor(inode), routine);
260 if (tty->magic != TTY_MAGIC) {
262 "bad magic number for tty struct (%d:%d) in %s\n",
263 imajor(inode), iminor(inode), routine);
270 static int check_tty_count(struct tty_struct *tty, const char *routine)
272 #ifdef CHECK_TTY_COUNT
276 spin_lock(&tty_files_lock);
277 list_for_each(p, &tty->tty_files) {
280 spin_unlock(&tty_files_lock);
281 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
282 tty->driver->subtype == PTY_TYPE_SLAVE &&
283 tty->link && tty->link->count)
285 if (tty->count != count) {
286 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
287 "!= #fd's(%d) in %s\n",
288 tty->name, tty->count, count, routine);
296 * get_tty_driver - find device of a tty
297 * @dev_t: device identifier
298 * @index: returns the index of the tty
300 * This routine returns a tty driver structure, given a device number
301 * and also passes back the index number.
303 * Locking: caller must hold tty_mutex
306 static struct tty_driver *get_tty_driver(dev_t device, int *index)
308 struct tty_driver *p;
310 list_for_each_entry(p, &tty_drivers, tty_drivers) {
311 dev_t base = MKDEV(p->major, p->minor_start);
312 if (device < base || device >= base + p->num)
314 *index = device - base;
315 return tty_driver_kref_get(p);
320 #ifdef CONFIG_CONSOLE_POLL
323 * tty_find_polling_driver - find device of a polled tty
324 * @name: name string to match
325 * @line: pointer to resulting tty line nr
327 * This routine returns a tty driver structure, given a name
328 * and the condition that the tty driver is capable of polled
331 struct tty_driver *tty_find_polling_driver(char *name, int *line)
333 struct tty_driver *p, *res = NULL;
338 for (str = name; *str; str++)
339 if ((*str >= '0' && *str <= '9') || *str == ',')
345 tty_line = simple_strtoul(str, &str, 10);
347 mutex_lock(&tty_mutex);
348 /* Search through the tty devices to look for a match */
349 list_for_each_entry(p, &tty_drivers, tty_drivers) {
350 if (strncmp(name, p->name, len) != 0)
358 if (tty_line >= 0 && tty_line < p->num && p->ops &&
359 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
360 res = tty_driver_kref_get(p);
365 mutex_unlock(&tty_mutex);
369 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
373 * tty_check_change - check for POSIX terminal changes
376 * If we try to write to, or set the state of, a terminal and we're
377 * not in the foreground, send a SIGTTOU. If the signal is blocked or
378 * ignored, go ahead and perform the operation. (POSIX 7.2)
383 int tty_check_change(struct tty_struct *tty)
388 if (current->signal->tty != tty)
391 spin_lock_irqsave(&tty->ctrl_lock, flags);
394 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
397 if (task_pgrp(current) == tty->pgrp)
399 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
400 if (is_ignored(SIGTTOU))
402 if (is_current_pgrp_orphaned()) {
406 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
407 set_thread_flag(TIF_SIGPENDING);
412 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
416 EXPORT_SYMBOL(tty_check_change);
418 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
419 size_t count, loff_t *ppos)
424 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
425 size_t count, loff_t *ppos)
430 /* No kernel lock held - none needed ;) */
431 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
433 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
436 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
439 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
442 static long hung_up_tty_compat_ioctl(struct file *file,
443 unsigned int cmd, unsigned long arg)
445 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
448 static const struct file_operations tty_fops = {
453 .unlocked_ioctl = tty_ioctl,
454 .compat_ioctl = tty_compat_ioctl,
456 .release = tty_release,
457 .fasync = tty_fasync,
460 static const struct file_operations console_fops = {
463 .write = redirected_tty_write,
465 .unlocked_ioctl = tty_ioctl,
466 .compat_ioctl = tty_compat_ioctl,
468 .release = tty_release,
469 .fasync = tty_fasync,
472 static const struct file_operations hung_up_tty_fops = {
474 .read = hung_up_tty_read,
475 .write = hung_up_tty_write,
476 .poll = hung_up_tty_poll,
477 .unlocked_ioctl = hung_up_tty_ioctl,
478 .compat_ioctl = hung_up_tty_compat_ioctl,
479 .release = tty_release,
482 static DEFINE_SPINLOCK(redirect_lock);
483 static struct file *redirect;
486 * tty_wakeup - request more data
489 * Internal and external helper for wakeups of tty. This function
490 * informs the line discipline if present that the driver is ready
491 * to receive more output data.
494 void tty_wakeup(struct tty_struct *tty)
496 struct tty_ldisc *ld;
498 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
499 ld = tty_ldisc_ref(tty);
501 if (ld->ops->write_wakeup)
502 ld->ops->write_wakeup(tty);
506 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
509 EXPORT_SYMBOL_GPL(tty_wakeup);
512 * __tty_hangup - actual handler for hangup events
515 * This can be called by the "eventd" kernel thread. That is process
516 * synchronous but doesn't hold any locks, so we need to make sure we
517 * have the appropriate locks for what we're doing.
519 * The hangup event clears any pending redirections onto the hung up
520 * device. It ensures future writes will error and it does the needed
521 * line discipline hangup and signal delivery. The tty object itself
526 * redirect lock for undoing redirection
527 * file list lock for manipulating list of ttys
528 * tty_ldisc_lock from called functions
529 * termios_mutex resetting termios data
530 * tasklist_lock to walk task list for hangup event
531 * ->siglock to protect ->signal/->sighand
533 void __tty_hangup(struct tty_struct *tty)
535 struct file *cons_filp = NULL;
536 struct file *filp, *f = NULL;
537 struct task_struct *p;
538 struct tty_file_private *priv;
539 int closecount = 0, n;
547 spin_lock(&redirect_lock);
548 if (redirect && file_tty(redirect) == tty) {
552 spin_unlock(&redirect_lock);
556 /* inuse_filps is protected by the single tty lock,
557 this really needs to change if we want to flush the
558 workqueue with the lock held */
559 check_tty_count(tty, "tty_hangup");
561 spin_lock(&tty_files_lock);
562 /* This breaks for file handles being sent over AF_UNIX sockets ? */
563 list_for_each_entry(priv, &tty->tty_files, list) {
565 if (filp->f_op->write == redirected_tty_write)
567 if (filp->f_op->write != tty_write)
570 __tty_fasync(-1, filp, 0); /* can't block */
571 filp->f_op = &hung_up_tty_fops;
573 spin_unlock(&tty_files_lock);
575 tty_ldisc_hangup(tty);
577 read_lock(&tasklist_lock);
579 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
580 spin_lock_irq(&p->sighand->siglock);
581 if (p->signal->tty == tty) {
582 p->signal->tty = NULL;
583 /* We defer the dereferences outside fo
587 if (!p->signal->leader) {
588 spin_unlock_irq(&p->sighand->siglock);
591 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
592 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
593 put_pid(p->signal->tty_old_pgrp); /* A noop */
594 spin_lock_irqsave(&tty->ctrl_lock, flags);
596 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
597 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
598 spin_unlock_irq(&p->sighand->siglock);
599 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
601 read_unlock(&tasklist_lock);
603 spin_lock_irqsave(&tty->ctrl_lock, flags);
604 clear_bit(TTY_THROTTLED, &tty->flags);
605 clear_bit(TTY_PUSH, &tty->flags);
606 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
607 put_pid(tty->session);
611 tty->ctrl_status = 0;
612 set_bit(TTY_HUPPED, &tty->flags);
613 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
615 /* Account for the p->signal references we killed */
620 * If one of the devices matches a console pointer, we
621 * cannot just call hangup() because that will cause
622 * tty->count and state->count to go out of sync.
623 * So we just call close() the right number of times.
627 for (n = 0; n < closecount; n++)
628 tty->ops->close(tty, cons_filp);
629 } else if (tty->ops->hangup)
630 (tty->ops->hangup)(tty);
632 * We don't want to have driver/ldisc interactions beyond
633 * the ones we did here. The driver layer expects no
634 * calls after ->hangup() from the ldisc side. However we
635 * can't yet guarantee all that.
637 set_bit(TTY_HUPPED, &tty->flags);
638 tty_ldisc_enable(tty);
646 static void do_tty_hangup(struct work_struct *work)
648 struct tty_struct *tty =
649 container_of(work, struct tty_struct, hangup_work);
655 * tty_hangup - trigger a hangup event
656 * @tty: tty to hangup
658 * A carrier loss (virtual or otherwise) has occurred on this like
659 * schedule a hangup sequence to run after this event.
662 void tty_hangup(struct tty_struct *tty)
664 #ifdef TTY_DEBUG_HANGUP
666 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
668 schedule_work(&tty->hangup_work);
671 EXPORT_SYMBOL(tty_hangup);
674 * tty_vhangup - process vhangup
675 * @tty: tty to hangup
677 * The user has asked via system call for the terminal to be hung up.
678 * We do this synchronously so that when the syscall returns the process
679 * is complete. That guarantee is necessary for security reasons.
682 void tty_vhangup(struct tty_struct *tty)
684 #ifdef TTY_DEBUG_HANGUP
687 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
692 EXPORT_SYMBOL(tty_vhangup);
696 * tty_vhangup_self - process vhangup for own ctty
698 * Perform a vhangup on the current controlling tty
701 void tty_vhangup_self(void)
703 struct tty_struct *tty;
705 tty = get_current_tty();
713 * tty_hung_up_p - was tty hung up
714 * @filp: file pointer of tty
716 * Return true if the tty has been subject to a vhangup or a carrier
720 int tty_hung_up_p(struct file *filp)
722 return (filp->f_op == &hung_up_tty_fops);
725 EXPORT_SYMBOL(tty_hung_up_p);
727 static void session_clear_tty(struct pid *session)
729 struct task_struct *p;
730 do_each_pid_task(session, PIDTYPE_SID, p) {
732 } while_each_pid_task(session, PIDTYPE_SID, p);
736 * disassociate_ctty - disconnect controlling tty
737 * @on_exit: true if exiting so need to "hang up" the session
739 * This function is typically called only by the session leader, when
740 * it wants to disassociate itself from its controlling tty.
742 * It performs the following functions:
743 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
744 * (2) Clears the tty from being controlling the session
745 * (3) Clears the controlling tty for all processes in the
748 * The argument on_exit is set to 1 if called when a process is
749 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
752 * BTM is taken for hysterical raisins, and held when
753 * called from no_tty().
754 * tty_mutex is taken to protect tty
755 * ->siglock is taken to protect ->signal/->sighand
756 * tasklist_lock is taken to walk process list for sessions
757 * ->siglock is taken to protect ->signal/->sighand
760 void disassociate_ctty(int on_exit)
762 struct tty_struct *tty;
763 struct pid *tty_pgrp = NULL;
765 if (!current->signal->leader)
768 tty = get_current_tty();
770 tty_pgrp = get_pid(tty->pgrp);
772 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
776 } else if (on_exit) {
777 struct pid *old_pgrp;
778 spin_lock_irq(¤t->sighand->siglock);
779 old_pgrp = current->signal->tty_old_pgrp;
780 current->signal->tty_old_pgrp = NULL;
781 spin_unlock_irq(¤t->sighand->siglock);
783 kill_pgrp(old_pgrp, SIGHUP, on_exit);
784 kill_pgrp(old_pgrp, SIGCONT, on_exit);
790 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
792 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
796 spin_lock_irq(¤t->sighand->siglock);
797 put_pid(current->signal->tty_old_pgrp);
798 current->signal->tty_old_pgrp = NULL;
799 spin_unlock_irq(¤t->sighand->siglock);
801 tty = get_current_tty();
804 spin_lock_irqsave(&tty->ctrl_lock, flags);
805 put_pid(tty->session);
809 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
812 #ifdef TTY_DEBUG_HANGUP
813 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
818 /* Now clear signal->tty under the lock */
819 read_lock(&tasklist_lock);
820 session_clear_tty(task_session(current));
821 read_unlock(&tasklist_lock);
826 * no_tty - Ensure the current process does not have a controlling tty
830 struct task_struct *tsk = current;
832 disassociate_ctty(0);
839 * stop_tty - propagate flow control
842 * Perform flow control to the driver. For PTY/TTY pairs we
843 * must also propagate the TIOCKPKT status. May be called
844 * on an already stopped device and will not re-call the driver
847 * This functionality is used by both the line disciplines for
848 * halting incoming flow and by the driver. It may therefore be
849 * called from any context, may be under the tty atomic_write_lock
853 * Uses the tty control lock internally
856 void stop_tty(struct tty_struct *tty)
859 spin_lock_irqsave(&tty->ctrl_lock, flags);
861 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
865 if (tty->link && tty->link->packet) {
866 tty->ctrl_status &= ~TIOCPKT_START;
867 tty->ctrl_status |= TIOCPKT_STOP;
868 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
870 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
872 (tty->ops->stop)(tty);
875 EXPORT_SYMBOL(stop_tty);
878 * start_tty - propagate flow control
881 * Start a tty that has been stopped if at all possible. Perform
882 * any necessary wakeups and propagate the TIOCPKT status. If this
883 * is the tty was previous stopped and is being started then the
884 * driver start method is invoked and the line discipline woken.
890 void start_tty(struct tty_struct *tty)
893 spin_lock_irqsave(&tty->ctrl_lock, flags);
894 if (!tty->stopped || tty->flow_stopped) {
895 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
899 if (tty->link && tty->link->packet) {
900 tty->ctrl_status &= ~TIOCPKT_STOP;
901 tty->ctrl_status |= TIOCPKT_START;
902 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
904 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
906 (tty->ops->start)(tty);
907 /* If we have a running line discipline it may need kicking */
911 EXPORT_SYMBOL(start_tty);
914 * tty_read - read method for tty device files
915 * @file: pointer to tty file
917 * @count: size of user buffer
920 * Perform the read system call function on this terminal device. Checks
921 * for hung up devices before calling the line discipline method.
924 * Locks the line discipline internally while needed. Multiple
925 * read calls may be outstanding in parallel.
928 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
932 struct inode *inode = file->f_path.dentry->d_inode;
933 struct tty_struct *tty = file_tty(file);
934 struct tty_ldisc *ld;
936 if (tty_paranoia_check(tty, inode, "tty_read"))
938 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
941 /* We want to wait for the line discipline to sort out in this
943 ld = tty_ldisc_ref_wait(tty);
945 i = (ld->ops->read)(tty, file, buf, count);
950 inode->i_atime = current_fs_time(inode->i_sb);
954 void tty_write_unlock(struct tty_struct *tty)
956 mutex_unlock(&tty->atomic_write_lock);
957 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
960 int tty_write_lock(struct tty_struct *tty, int ndelay)
962 if (!mutex_trylock(&tty->atomic_write_lock)) {
965 if (mutex_lock_interruptible(&tty->atomic_write_lock))
972 * Split writes up in sane blocksizes to avoid
973 * denial-of-service type attacks
975 static inline ssize_t do_tty_write(
976 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
977 struct tty_struct *tty,
979 const char __user *buf,
982 ssize_t ret, written = 0;
985 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
990 * We chunk up writes into a temporary buffer. This
991 * simplifies low-level drivers immensely, since they
992 * don't have locking issues and user mode accesses.
994 * But if TTY_NO_WRITE_SPLIT is set, we should use a
997 * The default chunk-size is 2kB, because the NTTY
998 * layer has problems with bigger chunks. It will
999 * claim to be able to handle more characters than
1002 * FIXME: This can probably go away now except that 64K chunks
1003 * are too likely to fail unless switched to vmalloc...
1006 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1011 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1012 if (tty->write_cnt < chunk) {
1013 unsigned char *buf_chunk;
1018 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1023 kfree(tty->write_buf);
1024 tty->write_cnt = chunk;
1025 tty->write_buf = buf_chunk;
1028 /* Do the write .. */
1030 size_t size = count;
1034 if (copy_from_user(tty->write_buf, buf, size))
1036 ret = write(tty, file, tty->write_buf, size);
1045 if (signal_pending(current))
1050 struct inode *inode = file->f_path.dentry->d_inode;
1051 inode->i_mtime = current_fs_time(inode->i_sb);
1055 tty_write_unlock(tty);
1060 * tty_write_message - write a message to a certain tty, not just the console.
1061 * @tty: the destination tty_struct
1062 * @msg: the message to write
1064 * This is used for messages that need to be redirected to a specific tty.
1065 * We don't put it into the syslog queue right now maybe in the future if
1068 * We must still hold the BTM and test the CLOSING flag for the moment.
1071 void tty_write_message(struct tty_struct *tty, char *msg)
1074 mutex_lock(&tty->atomic_write_lock);
1076 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1078 tty->ops->write(tty, msg, strlen(msg));
1081 tty_write_unlock(tty);
1088 * tty_write - write method for tty device file
1089 * @file: tty file pointer
1090 * @buf: user data to write
1091 * @count: bytes to write
1094 * Write data to a tty device via the line discipline.
1097 * Locks the line discipline as required
1098 * Writes to the tty driver are serialized by the atomic_write_lock
1099 * and are then processed in chunks to the device. The line discipline
1100 * write method will not be invoked in parallel for each device.
1103 static ssize_t tty_write(struct file *file, const char __user *buf,
1104 size_t count, loff_t *ppos)
1106 struct inode *inode = file->f_path.dentry->d_inode;
1107 struct tty_struct *tty = file_tty(file);
1108 struct tty_ldisc *ld;
1111 if (tty_paranoia_check(tty, inode, "tty_write"))
1113 if (!tty || !tty->ops->write ||
1114 (test_bit(TTY_IO_ERROR, &tty->flags)))
1116 /* Short term debug to catch buggy drivers */
1117 if (tty->ops->write_room == NULL)
1118 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1120 ld = tty_ldisc_ref_wait(tty);
1121 if (!ld->ops->write)
1124 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1125 tty_ldisc_deref(ld);
1129 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1130 size_t count, loff_t *ppos)
1132 struct file *p = NULL;
1134 spin_lock(&redirect_lock);
1139 spin_unlock(&redirect_lock);
1143 res = vfs_write(p, buf, count, &p->f_pos);
1147 return tty_write(file, buf, count, ppos);
1150 static char ptychar[] = "pqrstuvwxyzabcde";
1153 * pty_line_name - generate name for a pty
1154 * @driver: the tty driver in use
1155 * @index: the minor number
1156 * @p: output buffer of at least 6 bytes
1158 * Generate a name from a driver reference and write it to the output
1163 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1165 int i = index + driver->name_base;
1166 /* ->name is initialized to "ttyp", but "tty" is expected */
1167 sprintf(p, "%s%c%x",
1168 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1169 ptychar[i >> 4 & 0xf], i & 0xf);
1173 * tty_line_name - generate name for a tty
1174 * @driver: the tty driver in use
1175 * @index: the minor number
1176 * @p: output buffer of at least 7 bytes
1178 * Generate a name from a driver reference and write it to the output
1183 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1185 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1189 * tty_driver_lookup_tty() - find an existing tty, if any
1190 * @driver: the driver for the tty
1191 * @idx: the minor number
1193 * Return the tty, if found or ERR_PTR() otherwise.
1195 * Locking: tty_mutex must be held. If tty is found, the mutex must
1196 * be held until the 'fast-open' is also done. Will change once we
1197 * have refcounting in the driver and per driver locking
1199 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1200 struct inode *inode, int idx)
1202 struct tty_struct *tty;
1204 if (driver->ops->lookup)
1205 return driver->ops->lookup(driver, inode, idx);
1207 tty = driver->ttys[idx];
1212 * tty_init_termios - helper for termios setup
1213 * @tty: the tty to set up
1215 * Initialise the termios structures for this tty. Thus runs under
1216 * the tty_mutex currently so we can be relaxed about ordering.
1219 int tty_init_termios(struct tty_struct *tty)
1221 struct ktermios *tp;
1222 int idx = tty->index;
1224 tp = tty->driver->termios[idx];
1226 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1229 memcpy(tp, &tty->driver->init_termios,
1230 sizeof(struct ktermios));
1231 tty->driver->termios[idx] = tp;
1234 tty->termios_locked = tp + 1;
1236 /* Compatibility until drivers always set this */
1237 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1238 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1241 EXPORT_SYMBOL_GPL(tty_init_termios);
1244 * tty_driver_install_tty() - install a tty entry in the driver
1245 * @driver: the driver for the tty
1248 * Install a tty object into the driver tables. The tty->index field
1249 * will be set by the time this is called. This method is responsible
1250 * for ensuring any need additional structures are allocated and
1253 * Locking: tty_mutex for now
1255 static int tty_driver_install_tty(struct tty_driver *driver,
1256 struct tty_struct *tty)
1258 int idx = tty->index;
1261 if (driver->ops->install) {
1262 ret = driver->ops->install(driver, tty);
1266 if (tty_init_termios(tty) == 0) {
1267 tty_driver_kref_get(driver);
1269 driver->ttys[idx] = tty;
1276 * tty_driver_remove_tty() - remove a tty from the driver tables
1277 * @driver: the driver for the tty
1278 * @idx: the minor number
1280 * Remvoe a tty object from the driver tables. The tty->index field
1281 * will be set by the time this is called.
1283 * Locking: tty_mutex for now
1285 static void tty_driver_remove_tty(struct tty_driver *driver,
1286 struct tty_struct *tty)
1288 if (driver->ops->remove)
1289 driver->ops->remove(driver, tty);
1291 driver->ttys[tty->index] = NULL;
1295 * tty_reopen() - fast re-open of an open tty
1296 * @tty - the tty to open
1298 * Return 0 on success, -errno on error.
1300 * Locking: tty_mutex must be held from the time the tty was found
1301 * till this open completes.
1303 static int tty_reopen(struct tty_struct *tty)
1305 struct tty_driver *driver = tty->driver;
1307 if (test_bit(TTY_CLOSING, &tty->flags) ||
1308 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1311 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1312 driver->subtype == PTY_TYPE_MASTER) {
1314 * special case for PTY masters: only one open permitted,
1315 * and the slave side open count is incremented as well.
1323 tty->driver = driver; /* N.B. why do this every time?? */
1325 mutex_lock(&tty->ldisc_mutex);
1326 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1327 mutex_unlock(&tty->ldisc_mutex);
1333 * tty_init_dev - initialise a tty device
1334 * @driver: tty driver we are opening a device on
1335 * @idx: device index
1336 * @ret_tty: returned tty structure
1337 * @first_ok: ok to open a new device (used by ptmx)
1339 * Prepare a tty device. This may not be a "new" clean device but
1340 * could also be an active device. The pty drivers require special
1341 * handling because of this.
1344 * The function is called under the tty_mutex, which
1345 * protects us from the tty struct or driver itself going away.
1347 * On exit the tty device has the line discipline attached and
1348 * a reference count of 1. If a pair was created for pty/tty use
1349 * and the other was a pty master then it too has a reference count of 1.
1351 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1352 * failed open. The new code protects the open with a mutex, so it's
1353 * really quite straightforward. The mutex locking can probably be
1354 * relaxed for the (most common) case of reopening a tty.
1357 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1360 struct tty_struct *tty;
1363 /* Check if pty master is being opened multiple times */
1364 if (driver->subtype == PTY_TYPE_MASTER &&
1365 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1366 return ERR_PTR(-EIO);
1370 * First time open is complex, especially for PTY devices.
1371 * This code guarantees that either everything succeeds and the
1372 * TTY is ready for operation, or else the table slots are vacated
1373 * and the allocated memory released. (Except that the termios
1374 * and locked termios may be retained.)
1377 if (!try_module_get(driver->owner))
1378 return ERR_PTR(-ENODEV);
1380 tty = alloc_tty_struct();
1383 initialize_tty_struct(tty, driver, idx);
1385 retval = tty_driver_install_tty(driver, tty);
1387 free_tty_struct(tty);
1388 module_put(driver->owner);
1389 return ERR_PTR(retval);
1393 * Structures all installed ... call the ldisc open routines.
1394 * If we fail here just call release_tty to clean up. No need
1395 * to decrement the use counts, as release_tty doesn't care.
1397 retval = tty_ldisc_setup(tty, tty->link);
1399 goto release_mem_out;
1403 module_put(driver->owner);
1404 return ERR_PTR(-ENOMEM);
1406 /* call the tty release_tty routine to clean out this slot */
1408 if (printk_ratelimit())
1409 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1410 "clearing slot %d\n", idx);
1411 release_tty(tty, idx);
1412 return ERR_PTR(retval);
1415 void tty_free_termios(struct tty_struct *tty)
1417 struct ktermios *tp;
1418 int idx = tty->index;
1419 /* Kill this flag and push into drivers for locking etc */
1420 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1421 /* FIXME: Locking on ->termios array */
1423 tty->driver->termios[idx] = NULL;
1427 EXPORT_SYMBOL(tty_free_termios);
1429 void tty_shutdown(struct tty_struct *tty)
1431 tty_driver_remove_tty(tty->driver, tty);
1432 tty_free_termios(tty);
1434 EXPORT_SYMBOL(tty_shutdown);
1437 * release_one_tty - release tty structure memory
1438 * @kref: kref of tty we are obliterating
1440 * Releases memory associated with a tty structure, and clears out the
1441 * driver table slots. This function is called when a device is no longer
1442 * in use. It also gets called when setup of a device fails.
1445 * tty_mutex - sometimes only
1446 * takes the file list lock internally when working on the list
1447 * of ttys that the driver keeps.
1449 * This method gets called from a work queue so that the driver private
1450 * cleanup ops can sleep (needed for USB at least)
1452 static void release_one_tty(struct work_struct *work)
1454 struct tty_struct *tty =
1455 container_of(work, struct tty_struct, hangup_work);
1456 struct tty_driver *driver = tty->driver;
1458 if (tty->ops->cleanup)
1459 tty->ops->cleanup(tty);
1462 tty_driver_kref_put(driver);
1463 module_put(driver->owner);
1465 spin_lock(&tty_files_lock);
1466 list_del_init(&tty->tty_files);
1467 spin_unlock(&tty_files_lock);
1470 put_pid(tty->session);
1471 free_tty_struct(tty);
1474 static void queue_release_one_tty(struct kref *kref)
1476 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1478 if (tty->ops->shutdown)
1479 tty->ops->shutdown(tty);
1483 /* The hangup queue is now free so we can reuse it rather than
1484 waste a chunk of memory for each port */
1485 INIT_WORK(&tty->hangup_work, release_one_tty);
1486 schedule_work(&tty->hangup_work);
1490 * tty_kref_put - release a tty kref
1493 * Release a reference to a tty device and if need be let the kref
1494 * layer destruct the object for us
1497 void tty_kref_put(struct tty_struct *tty)
1500 kref_put(&tty->kref, queue_release_one_tty);
1502 EXPORT_SYMBOL(tty_kref_put);
1505 * release_tty - release tty structure memory
1507 * Release both @tty and a possible linked partner (think pty pair),
1508 * and decrement the refcount of the backing module.
1511 * tty_mutex - sometimes only
1512 * takes the file list lock internally when working on the list
1513 * of ttys that the driver keeps.
1514 * FIXME: should we require tty_mutex is held here ??
1517 static void release_tty(struct tty_struct *tty, int idx)
1519 /* This should always be true but check for the moment */
1520 WARN_ON(tty->index != idx);
1523 tty_kref_put(tty->link);
1528 * tty_release - vfs callback for close
1529 * @inode: inode of tty
1530 * @filp: file pointer for handle to tty
1532 * Called the last time each file handle is closed that references
1533 * this tty. There may however be several such references.
1536 * Takes bkl. See tty_release_dev
1538 * Even releasing the tty structures is a tricky business.. We have
1539 * to be very careful that the structures are all released at the
1540 * same time, as interrupts might otherwise get the wrong pointers.
1542 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1543 * lead to double frees or releasing memory still in use.
1546 int tty_release(struct inode *inode, struct file *filp)
1548 struct tty_struct *tty = file_tty(filp);
1549 struct tty_struct *o_tty;
1550 int pty_master, tty_closing, o_tty_closing, do_sleep;
1555 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1559 check_tty_count(tty, "tty_release_dev");
1561 __tty_fasync(-1, filp, 0);
1564 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1565 tty->driver->subtype == PTY_TYPE_MASTER);
1566 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1569 #ifdef TTY_PARANOIA_CHECK
1570 if (idx < 0 || idx >= tty->driver->num) {
1571 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1572 "free (%s)\n", tty->name);
1577 if (tty != tty->driver->ttys[idx]) {
1579 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1580 "for (%s)\n", idx, tty->name);
1583 if (tty->termios != tty->driver->termios[idx]) {
1585 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1593 #ifdef TTY_DEBUG_HANGUP
1594 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1595 tty_name(tty, buf), tty->count);
1598 #ifdef TTY_PARANOIA_CHECK
1599 if (tty->driver->other &&
1600 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1601 if (o_tty != tty->driver->other->ttys[idx]) {
1603 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1604 "not o_tty for (%s)\n",
1608 if (o_tty->termios != tty->driver->other->termios[idx]) {
1610 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1611 "not o_termios for (%s)\n",
1615 if (o_tty->link != tty) {
1617 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1622 if (tty->ops->close)
1623 tty->ops->close(tty, filp);
1627 * Sanity check: if tty->count is going to zero, there shouldn't be
1628 * any waiters on tty->read_wait or tty->write_wait. We test the
1629 * wait queues and kick everyone out _before_ actually starting to
1630 * close. This ensures that we won't block while releasing the tty
1633 * The test for the o_tty closing is necessary, since the master and
1634 * slave sides may close in any order. If the slave side closes out
1635 * first, its count will be one, since the master side holds an open.
1636 * Thus this test wouldn't be triggered at the time the slave closes,
1639 * Note that it's possible for the tty to be opened again while we're
1640 * flushing out waiters. By recalculating the closing flags before
1641 * each iteration we avoid any problems.
1644 /* Guard against races with tty->count changes elsewhere and
1645 opens on /dev/tty */
1647 mutex_lock(&tty_mutex);
1649 tty_closing = tty->count <= 1;
1650 o_tty_closing = o_tty &&
1651 (o_tty->count <= (pty_master ? 1 : 0));
1655 if (waitqueue_active(&tty->read_wait)) {
1656 wake_up_poll(&tty->read_wait, POLLIN);
1659 if (waitqueue_active(&tty->write_wait)) {
1660 wake_up_poll(&tty->write_wait, POLLOUT);
1664 if (o_tty_closing) {
1665 if (waitqueue_active(&o_tty->read_wait)) {
1666 wake_up_poll(&o_tty->read_wait, POLLIN);
1669 if (waitqueue_active(&o_tty->write_wait)) {
1670 wake_up_poll(&o_tty->write_wait, POLLOUT);
1677 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1678 "active!\n", tty_name(tty, buf));
1680 mutex_unlock(&tty_mutex);
1685 * The closing flags are now consistent with the open counts on
1686 * both sides, and we've completed the last operation that could
1687 * block, so it's safe to proceed with closing.
1690 if (--o_tty->count < 0) {
1691 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1693 o_tty->count, tty_name(o_tty, buf));
1697 if (--tty->count < 0) {
1698 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1699 tty->count, tty_name(tty, buf));
1704 * We've decremented tty->count, so we need to remove this file
1705 * descriptor off the tty->tty_files list; this serves two
1707 * - check_tty_count sees the correct number of file descriptors
1708 * associated with this tty.
1709 * - do_tty_hangup no longer sees this file descriptor as
1710 * something that needs to be handled for hangups.
1715 * Perform some housekeeping before deciding whether to return.
1717 * Set the TTY_CLOSING flag if this was the last open. In the
1718 * case of a pty we may have to wait around for the other side
1719 * to close, and TTY_CLOSING makes sure we can't be reopened.
1722 set_bit(TTY_CLOSING, &tty->flags);
1724 set_bit(TTY_CLOSING, &o_tty->flags);
1727 * If _either_ side is closing, make sure there aren't any
1728 * processes that still think tty or o_tty is their controlling
1731 if (tty_closing || o_tty_closing) {
1732 read_lock(&tasklist_lock);
1733 session_clear_tty(tty->session);
1735 session_clear_tty(o_tty->session);
1736 read_unlock(&tasklist_lock);
1739 mutex_unlock(&tty_mutex);
1741 /* check whether both sides are closing ... */
1742 if (!tty_closing || (o_tty && !o_tty_closing)) {
1747 #ifdef TTY_DEBUG_HANGUP
1748 printk(KERN_DEBUG "freeing tty structure...");
1751 * Ask the line discipline code to release its structures
1753 tty_ldisc_release(tty, o_tty);
1755 * The release_tty function takes care of the details of clearing
1756 * the slots and preserving the termios structure.
1758 release_tty(tty, idx);
1760 /* Make this pty number available for reallocation */
1762 devpts_kill_index(inode, idx);
1768 * tty_open - open a tty device
1769 * @inode: inode of device file
1770 * @filp: file pointer to tty
1772 * tty_open and tty_release keep up the tty count that contains the
1773 * number of opens done on a tty. We cannot use the inode-count, as
1774 * different inodes might point to the same tty.
1776 * Open-counting is needed for pty masters, as well as for keeping
1777 * track of serial lines: DTR is dropped when the last close happens.
1778 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1780 * The termios state of a pty is reset on first open so that
1781 * settings don't persist across reuse.
1783 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1784 * tty->count should protect the rest.
1785 * ->siglock protects ->signal/->sighand
1788 static int tty_open(struct inode *inode, struct file *filp)
1790 struct tty_struct *tty = NULL;
1792 struct tty_driver *driver;
1794 dev_t device = inode->i_rdev;
1795 unsigned saved_flags = filp->f_flags;
1797 nonseekable_open(inode, filp);
1800 noctty = filp->f_flags & O_NOCTTY;
1804 mutex_lock(&tty_mutex);
1807 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1808 tty = get_current_tty();
1811 mutex_unlock(&tty_mutex);
1814 driver = tty_driver_kref_get(tty->driver);
1816 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1818 /* FIXME: Should we take a driver reference ? */
1823 if (device == MKDEV(TTY_MAJOR, 0)) {
1824 extern struct tty_driver *console_driver;
1825 driver = tty_driver_kref_get(console_driver);
1831 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1832 struct tty_driver *console_driver = console_device(&index);
1833 if (console_driver) {
1834 driver = tty_driver_kref_get(console_driver);
1836 /* Don't let /dev/console block */
1837 filp->f_flags |= O_NONBLOCK;
1843 mutex_unlock(&tty_mutex);
1847 driver = get_tty_driver(device, &index);
1850 mutex_unlock(&tty_mutex);
1855 /* check whether we're reopening an existing tty */
1856 tty = tty_driver_lookup_tty(driver, inode, index);
1860 mutex_unlock(&tty_mutex);
1861 return PTR_ERR(tty);
1866 retval = tty_reopen(tty);
1868 tty = ERR_PTR(retval);
1870 tty = tty_init_dev(driver, index, 0);
1872 mutex_unlock(&tty_mutex);
1873 tty_driver_kref_put(driver);
1876 return PTR_ERR(tty);
1879 tty_add_file(tty, filp);
1881 check_tty_count(tty, "tty_open");
1882 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1883 tty->driver->subtype == PTY_TYPE_MASTER)
1885 #ifdef TTY_DEBUG_HANGUP
1886 printk(KERN_DEBUG "opening %s...", tty->name);
1890 retval = tty->ops->open(tty, filp);
1894 filp->f_flags = saved_flags;
1896 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1897 !capable(CAP_SYS_ADMIN))
1901 #ifdef TTY_DEBUG_HANGUP
1902 printk(KERN_DEBUG "error %d in opening %s...", retval,
1905 tty_unlock(); /* need to call tty_release without BTM */
1906 tty_release(inode, filp);
1907 if (retval != -ERESTARTSYS)
1910 if (signal_pending(current))
1915 * Need to reset f_op in case a hangup happened.
1918 if (filp->f_op == &hung_up_tty_fops)
1919 filp->f_op = &tty_fops;
1926 mutex_lock(&tty_mutex);
1928 spin_lock_irq(¤t->sighand->siglock);
1930 current->signal->leader &&
1931 !current->signal->tty &&
1932 tty->session == NULL)
1933 __proc_set_tty(current, tty);
1934 spin_unlock_irq(¤t->sighand->siglock);
1936 mutex_unlock(&tty_mutex);
1943 * tty_poll - check tty status
1944 * @filp: file being polled
1945 * @wait: poll wait structures to update
1947 * Call the line discipline polling method to obtain the poll
1948 * status of the device.
1950 * Locking: locks called line discipline but ldisc poll method
1951 * may be re-entered freely by other callers.
1954 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1956 struct tty_struct *tty = file_tty(filp);
1957 struct tty_ldisc *ld;
1960 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1963 ld = tty_ldisc_ref_wait(tty);
1965 ret = (ld->ops->poll)(tty, filp, wait);
1966 tty_ldisc_deref(ld);
1970 static int __tty_fasync(int fd, struct file *filp, int on)
1972 struct tty_struct *tty = file_tty(filp);
1973 unsigned long flags;
1976 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1979 retval = fasync_helper(fd, filp, on, &tty->fasync);
1986 if (!waitqueue_active(&tty->read_wait))
1987 tty->minimum_to_wake = 1;
1988 spin_lock_irqsave(&tty->ctrl_lock, flags);
1991 type = PIDTYPE_PGID;
1993 pid = task_pid(current);
1997 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1998 retval = __f_setown(filp, pid, type, 0);
2003 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2004 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2011 static int tty_fasync(int fd, struct file *filp, int on)
2015 retval = __tty_fasync(fd, filp, on);
2021 * tiocsti - fake input character
2022 * @tty: tty to fake input into
2023 * @p: pointer to character
2025 * Fake input to a tty device. Does the necessary locking and
2028 * FIXME: does not honour flow control ??
2031 * Called functions take tty_ldisc_lock
2032 * current->signal->tty check is safe without locks
2034 * FIXME: may race normal receive processing
2037 static int tiocsti(struct tty_struct *tty, char __user *p)
2040 struct tty_ldisc *ld;
2042 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2044 if (get_user(ch, p))
2046 tty_audit_tiocsti(tty, ch);
2047 ld = tty_ldisc_ref_wait(tty);
2048 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2049 tty_ldisc_deref(ld);
2054 * tiocgwinsz - implement window query ioctl
2056 * @arg: user buffer for result
2058 * Copies the kernel idea of the window size into the user buffer.
2060 * Locking: tty->termios_mutex is taken to ensure the winsize data
2064 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2068 mutex_lock(&tty->termios_mutex);
2069 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2070 mutex_unlock(&tty->termios_mutex);
2072 return err ? -EFAULT: 0;
2076 * tty_do_resize - resize event
2077 * @tty: tty being resized
2078 * @rows: rows (character)
2079 * @cols: cols (character)
2081 * Update the termios variables and send the necessary signals to
2082 * peform a terminal resize correctly
2085 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2088 unsigned long flags;
2091 mutex_lock(&tty->termios_mutex);
2092 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2094 /* Get the PID values and reference them so we can
2095 avoid holding the tty ctrl lock while sending signals */
2096 spin_lock_irqsave(&tty->ctrl_lock, flags);
2097 pgrp = get_pid(tty->pgrp);
2098 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2101 kill_pgrp(pgrp, SIGWINCH, 1);
2106 mutex_unlock(&tty->termios_mutex);
2111 * tiocswinsz - implement window size set ioctl
2112 * @tty; tty side of tty
2113 * @arg: user buffer for result
2115 * Copies the user idea of the window size to the kernel. Traditionally
2116 * this is just advisory information but for the Linux console it
2117 * actually has driver level meaning and triggers a VC resize.
2120 * Driver dependant. The default do_resize method takes the
2121 * tty termios mutex and ctrl_lock. The console takes its own lock
2122 * then calls into the default method.
2125 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2127 struct winsize tmp_ws;
2128 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2131 if (tty->ops->resize)
2132 return tty->ops->resize(tty, &tmp_ws);
2134 return tty_do_resize(tty, &tmp_ws);
2138 * tioccons - allow admin to move logical console
2139 * @file: the file to become console
2141 * Allow the adminstrator to move the redirected console device
2143 * Locking: uses redirect_lock to guard the redirect information
2146 static int tioccons(struct file *file)
2148 if (!capable(CAP_SYS_ADMIN))
2150 if (file->f_op->write == redirected_tty_write) {
2152 spin_lock(&redirect_lock);
2155 spin_unlock(&redirect_lock);
2160 spin_lock(&redirect_lock);
2162 spin_unlock(&redirect_lock);
2167 spin_unlock(&redirect_lock);
2172 * fionbio - non blocking ioctl
2173 * @file: file to set blocking value
2174 * @p: user parameter
2176 * Historical tty interfaces had a blocking control ioctl before
2177 * the generic functionality existed. This piece of history is preserved
2178 * in the expected tty API of posix OS's.
2180 * Locking: none, the open file handle ensures it won't go away.
2183 static int fionbio(struct file *file, int __user *p)
2187 if (get_user(nonblock, p))
2190 spin_lock(&file->f_lock);
2192 file->f_flags |= O_NONBLOCK;
2194 file->f_flags &= ~O_NONBLOCK;
2195 spin_unlock(&file->f_lock);
2200 * tiocsctty - set controlling tty
2201 * @tty: tty structure
2202 * @arg: user argument
2204 * This ioctl is used to manage job control. It permits a session
2205 * leader to set this tty as the controlling tty for the session.
2208 * Takes tty_mutex() to protect tty instance
2209 * Takes tasklist_lock internally to walk sessions
2210 * Takes ->siglock() when updating signal->tty
2213 static int tiocsctty(struct tty_struct *tty, int arg)
2216 if (current->signal->leader && (task_session(current) == tty->session))
2219 mutex_lock(&tty_mutex);
2221 * The process must be a session leader and
2222 * not have a controlling tty already.
2224 if (!current->signal->leader || current->signal->tty) {
2231 * This tty is already the controlling
2232 * tty for another session group!
2234 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2238 read_lock(&tasklist_lock);
2239 session_clear_tty(tty->session);
2240 read_unlock(&tasklist_lock);
2246 proc_set_tty(current, tty);
2248 mutex_unlock(&tty_mutex);
2253 * tty_get_pgrp - return a ref counted pgrp pid
2256 * Returns a refcounted instance of the pid struct for the process
2257 * group controlling the tty.
2260 struct pid *tty_get_pgrp(struct tty_struct *tty)
2262 unsigned long flags;
2265 spin_lock_irqsave(&tty->ctrl_lock, flags);
2266 pgrp = get_pid(tty->pgrp);
2267 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2271 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2274 * tiocgpgrp - get process group
2275 * @tty: tty passed by user
2276 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2279 * Obtain the process group of the tty. If there is no process group
2282 * Locking: none. Reference to current->signal->tty is safe.
2285 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2290 * (tty == real_tty) is a cheap way of
2291 * testing if the tty is NOT a master pty.
2293 if (tty == real_tty && current->signal->tty != real_tty)
2295 pid = tty_get_pgrp(real_tty);
2296 ret = put_user(pid_vnr(pid), p);
2302 * tiocspgrp - attempt to set process group
2303 * @tty: tty passed by user
2304 * @real_tty: tty side device matching tty passed by user
2307 * Set the process group of the tty to the session passed. Only
2308 * permitted where the tty session is our session.
2310 * Locking: RCU, ctrl lock
2313 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2317 int retval = tty_check_change(real_tty);
2318 unsigned long flags;
2324 if (!current->signal->tty ||
2325 (current->signal->tty != real_tty) ||
2326 (real_tty->session != task_session(current)))
2328 if (get_user(pgrp_nr, p))
2333 pgrp = find_vpid(pgrp_nr);
2338 if (session_of_pgrp(pgrp) != task_session(current))
2341 spin_lock_irqsave(&tty->ctrl_lock, flags);
2342 put_pid(real_tty->pgrp);
2343 real_tty->pgrp = get_pid(pgrp);
2344 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2351 * tiocgsid - get session id
2352 * @tty: tty passed by user
2353 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2354 * @p: pointer to returned session id
2356 * Obtain the session id of the tty. If there is no session
2359 * Locking: none. Reference to current->signal->tty is safe.
2362 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2365 * (tty == real_tty) is a cheap way of
2366 * testing if the tty is NOT a master pty.
2368 if (tty == real_tty && current->signal->tty != real_tty)
2370 if (!real_tty->session)
2372 return put_user(pid_vnr(real_tty->session), p);
2376 * tiocsetd - set line discipline
2378 * @p: pointer to user data
2380 * Set the line discipline according to user request.
2382 * Locking: see tty_set_ldisc, this function is just a helper
2385 static int tiocsetd(struct tty_struct *tty, int __user *p)
2390 if (get_user(ldisc, p))
2393 ret = tty_set_ldisc(tty, ldisc);
2399 * send_break - performed time break
2400 * @tty: device to break on
2401 * @duration: timeout in mS
2403 * Perform a timed break on hardware that lacks its own driver level
2404 * timed break functionality.
2407 * atomic_write_lock serializes
2411 static int send_break(struct tty_struct *tty, unsigned int duration)
2415 if (tty->ops->break_ctl == NULL)
2418 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2419 retval = tty->ops->break_ctl(tty, duration);
2421 /* Do the work ourselves */
2422 if (tty_write_lock(tty, 0) < 0)
2424 retval = tty->ops->break_ctl(tty, -1);
2427 if (!signal_pending(current))
2428 msleep_interruptible(duration);
2429 retval = tty->ops->break_ctl(tty, 0);
2431 tty_write_unlock(tty);
2432 if (signal_pending(current))
2439 * tty_tiocmget - get modem status
2441 * @file: user file pointer
2442 * @p: pointer to result
2444 * Obtain the modem status bits from the tty driver if the feature
2445 * is supported. Return -EINVAL if it is not available.
2447 * Locking: none (up to the driver)
2450 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2452 int retval = -EINVAL;
2454 if (tty->ops->tiocmget) {
2455 retval = tty->ops->tiocmget(tty, file);
2458 retval = put_user(retval, p);
2464 * tty_tiocmset - set modem status
2466 * @file: user file pointer
2467 * @cmd: command - clear bits, set bits or set all
2468 * @p: pointer to desired bits
2470 * Set the modem status bits from the tty driver if the feature
2471 * is supported. Return -EINVAL if it is not available.
2473 * Locking: none (up to the driver)
2476 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2480 unsigned int set, clear, val;
2482 if (tty->ops->tiocmset == NULL)
2485 retval = get_user(val, p);
2501 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2502 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2503 return tty->ops->tiocmset(tty, file, set, clear);
2506 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2508 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2509 tty->driver->subtype == PTY_TYPE_MASTER)
2513 EXPORT_SYMBOL(tty_pair_get_tty);
2515 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2517 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2518 tty->driver->subtype == PTY_TYPE_MASTER)
2522 EXPORT_SYMBOL(tty_pair_get_pty);
2525 * Split this up, as gcc can choke on it otherwise..
2527 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2529 struct tty_struct *tty = file_tty(file);
2530 struct tty_struct *real_tty;
2531 void __user *p = (void __user *)arg;
2533 struct tty_ldisc *ld;
2534 struct inode *inode = file->f_dentry->d_inode;
2536 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2539 real_tty = tty_pair_get_tty(tty);
2542 * Factor out some common prep work
2550 retval = tty_check_change(tty);
2553 if (cmd != TIOCCBRK) {
2554 tty_wait_until_sent(tty, 0);
2555 if (signal_pending(current))
2566 return tiocsti(tty, p);
2568 return tiocgwinsz(real_tty, p);
2570 return tiocswinsz(real_tty, p);
2572 return real_tty != tty ? -EINVAL : tioccons(file);
2574 return fionbio(file, p);
2576 set_bit(TTY_EXCLUSIVE, &tty->flags);
2579 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2582 if (current->signal->tty != tty)
2587 return tiocsctty(tty, arg);
2589 return tiocgpgrp(tty, real_tty, p);
2591 return tiocspgrp(tty, real_tty, p);
2593 return tiocgsid(tty, real_tty, p);
2595 return put_user(tty->ldisc->ops->num, (int __user *)p);
2597 return tiocsetd(tty, p);
2601 case TIOCSBRK: /* Turn break on, unconditionally */
2602 if (tty->ops->break_ctl)
2603 return tty->ops->break_ctl(tty, -1);
2605 case TIOCCBRK: /* Turn break off, unconditionally */
2606 if (tty->ops->break_ctl)
2607 return tty->ops->break_ctl(tty, 0);
2609 case TCSBRK: /* SVID version: non-zero arg --> no break */
2610 /* non-zero arg means wait for all output data
2611 * to be sent (performed above) but don't send break.
2612 * This is used by the tcdrain() termios function.
2615 return send_break(tty, 250);
2617 case TCSBRKP: /* support for POSIX tcsendbreak() */
2618 return send_break(tty, arg ? arg*100 : 250);
2621 return tty_tiocmget(tty, file, p);
2625 return tty_tiocmset(tty, file, cmd, p);
2630 /* flush tty buffer and allow ldisc to process ioctl */
2631 tty_buffer_flush(tty);
2636 if (tty->ops->ioctl) {
2637 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2638 if (retval != -ENOIOCTLCMD)
2641 ld = tty_ldisc_ref_wait(tty);
2643 if (ld->ops->ioctl) {
2644 retval = ld->ops->ioctl(tty, file, cmd, arg);
2645 if (retval == -ENOIOCTLCMD)
2648 tty_ldisc_deref(ld);
2652 #ifdef CONFIG_COMPAT
2653 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2656 struct inode *inode = file->f_dentry->d_inode;
2657 struct tty_struct *tty = file_tty(file);
2658 struct tty_ldisc *ld;
2659 int retval = -ENOIOCTLCMD;
2661 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2664 if (tty->ops->compat_ioctl) {
2665 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2666 if (retval != -ENOIOCTLCMD)
2670 ld = tty_ldisc_ref_wait(tty);
2671 if (ld->ops->compat_ioctl)
2672 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2673 tty_ldisc_deref(ld);
2680 * This implements the "Secure Attention Key" --- the idea is to
2681 * prevent trojan horses by killing all processes associated with this
2682 * tty when the user hits the "Secure Attention Key". Required for
2683 * super-paranoid applications --- see the Orange Book for more details.
2685 * This code could be nicer; ideally it should send a HUP, wait a few
2686 * seconds, then send a INT, and then a KILL signal. But you then
2687 * have to coordinate with the init process, since all processes associated
2688 * with the current tty must be dead before the new getty is allowed
2691 * Now, if it would be correct ;-/ The current code has a nasty hole -
2692 * it doesn't catch files in flight. We may send the descriptor to ourselves
2693 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2695 * Nasty bug: do_SAK is being called in interrupt context. This can
2696 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2698 void __do_SAK(struct tty_struct *tty)
2703 struct task_struct *g, *p;
2704 struct pid *session;
2707 struct fdtable *fdt;
2711 session = tty->session;
2713 tty_ldisc_flush(tty);
2715 tty_driver_flush_buffer(tty);
2717 read_lock(&tasklist_lock);
2718 /* Kill the entire session */
2719 do_each_pid_task(session, PIDTYPE_SID, p) {
2720 printk(KERN_NOTICE "SAK: killed process %d"
2721 " (%s): task_session(p)==tty->session\n",
2722 task_pid_nr(p), p->comm);
2723 send_sig(SIGKILL, p, 1);
2724 } while_each_pid_task(session, PIDTYPE_SID, p);
2725 /* Now kill any processes that happen to have the
2728 do_each_thread(g, p) {
2729 if (p->signal->tty == tty) {
2730 printk(KERN_NOTICE "SAK: killed process %d"
2731 " (%s): task_session(p)==tty->session\n",
2732 task_pid_nr(p), p->comm);
2733 send_sig(SIGKILL, p, 1);
2739 * We don't take a ref to the file, so we must
2740 * hold ->file_lock instead.
2742 spin_lock(&p->files->file_lock);
2743 fdt = files_fdtable(p->files);
2744 for (i = 0; i < fdt->max_fds; i++) {
2745 filp = fcheck_files(p->files, i);
2748 if (filp->f_op->read == tty_read &&
2749 file_tty(filp) == tty) {
2750 printk(KERN_NOTICE "SAK: killed process %d"
2751 " (%s): fd#%d opened to the tty\n",
2752 task_pid_nr(p), p->comm, i);
2753 force_sig(SIGKILL, p);
2757 spin_unlock(&p->files->file_lock);
2760 } while_each_thread(g, p);
2761 read_unlock(&tasklist_lock);
2765 static void do_SAK_work(struct work_struct *work)
2767 struct tty_struct *tty =
2768 container_of(work, struct tty_struct, SAK_work);
2773 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2774 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2775 * the values which we write to it will be identical to the values which it
2776 * already has. --akpm
2778 void do_SAK(struct tty_struct *tty)
2782 schedule_work(&tty->SAK_work);
2785 EXPORT_SYMBOL(do_SAK);
2788 * initialize_tty_struct
2789 * @tty: tty to initialize
2791 * This subroutine initializes a tty structure that has been newly
2794 * Locking: none - tty in question must not be exposed at this point
2797 void initialize_tty_struct(struct tty_struct *tty,
2798 struct tty_driver *driver, int idx)
2800 memset(tty, 0, sizeof(struct tty_struct));
2801 kref_init(&tty->kref);
2802 tty->magic = TTY_MAGIC;
2803 tty_ldisc_init(tty);
2804 tty->session = NULL;
2806 tty->overrun_time = jiffies;
2807 tty->buf.head = tty->buf.tail = NULL;
2808 tty_buffer_init(tty);
2809 mutex_init(&tty->termios_mutex);
2810 mutex_init(&tty->ldisc_mutex);
2811 init_waitqueue_head(&tty->write_wait);
2812 init_waitqueue_head(&tty->read_wait);
2813 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2814 mutex_init(&tty->atomic_read_lock);
2815 mutex_init(&tty->atomic_write_lock);
2816 mutex_init(&tty->output_lock);
2817 mutex_init(&tty->echo_lock);
2818 spin_lock_init(&tty->read_lock);
2819 spin_lock_init(&tty->ctrl_lock);
2820 INIT_LIST_HEAD(&tty->tty_files);
2821 INIT_WORK(&tty->SAK_work, do_SAK_work);
2823 tty->driver = driver;
2824 tty->ops = driver->ops;
2826 tty_line_name(driver, idx, tty->name);
2830 * tty_put_char - write one character to a tty
2834 * Write one byte to the tty using the provided put_char method
2835 * if present. Returns the number of characters successfully output.
2837 * Note: the specific put_char operation in the driver layer may go
2838 * away soon. Don't call it directly, use this method
2841 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2843 if (tty->ops->put_char)
2844 return tty->ops->put_char(tty, ch);
2845 return tty->ops->write(tty, &ch, 1);
2847 EXPORT_SYMBOL_GPL(tty_put_char);
2849 struct class *tty_class;
2852 * tty_register_device - register a tty device
2853 * @driver: the tty driver that describes the tty device
2854 * @index: the index in the tty driver for this tty device
2855 * @device: a struct device that is associated with this tty device.
2856 * This field is optional, if there is no known struct device
2857 * for this tty device it can be set to NULL safely.
2859 * Returns a pointer to the struct device for this tty device
2860 * (or ERR_PTR(-EFOO) on error).
2862 * This call is required to be made to register an individual tty device
2863 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2864 * that bit is not set, this function should not be called by a tty
2870 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2871 struct device *device)
2874 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2876 if (index >= driver->num) {
2877 printk(KERN_ERR "Attempt to register invalid tty line number "
2879 return ERR_PTR(-EINVAL);
2882 if (driver->type == TTY_DRIVER_TYPE_PTY)
2883 pty_line_name(driver, index, name);
2885 tty_line_name(driver, index, name);
2887 return device_create(tty_class, device, dev, NULL, name);
2889 EXPORT_SYMBOL(tty_register_device);
2892 * tty_unregister_device - unregister a tty device
2893 * @driver: the tty driver that describes the tty device
2894 * @index: the index in the tty driver for this tty device
2896 * If a tty device is registered with a call to tty_register_device() then
2897 * this function must be called when the tty device is gone.
2902 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2904 device_destroy(tty_class,
2905 MKDEV(driver->major, driver->minor_start) + index);
2907 EXPORT_SYMBOL(tty_unregister_device);
2909 struct tty_driver *alloc_tty_driver(int lines)
2911 struct tty_driver *driver;
2913 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2915 kref_init(&driver->kref);
2916 driver->magic = TTY_DRIVER_MAGIC;
2917 driver->num = lines;
2918 /* later we'll move allocation of tables here */
2922 EXPORT_SYMBOL(alloc_tty_driver);
2924 static void destruct_tty_driver(struct kref *kref)
2926 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2928 struct ktermios *tp;
2931 if (driver->flags & TTY_DRIVER_INSTALLED) {
2933 * Free the termios and termios_locked structures because
2934 * we don't want to get memory leaks when modular tty
2935 * drivers are removed from the kernel.
2937 for (i = 0; i < driver->num; i++) {
2938 tp = driver->termios[i];
2940 driver->termios[i] = NULL;
2943 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2944 tty_unregister_device(driver, i);
2947 proc_tty_unregister_driver(driver);
2948 driver->ttys = NULL;
2949 driver->termios = NULL;
2951 cdev_del(&driver->cdev);
2956 void tty_driver_kref_put(struct tty_driver *driver)
2958 kref_put(&driver->kref, destruct_tty_driver);
2960 EXPORT_SYMBOL(tty_driver_kref_put);
2962 void tty_set_operations(struct tty_driver *driver,
2963 const struct tty_operations *op)
2967 EXPORT_SYMBOL(tty_set_operations);
2969 void put_tty_driver(struct tty_driver *d)
2971 tty_driver_kref_put(d);
2973 EXPORT_SYMBOL(put_tty_driver);
2976 * Called by a tty driver to register itself.
2978 int tty_register_driver(struct tty_driver *driver)
2985 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2986 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2991 if (!driver->major) {
2992 error = alloc_chrdev_region(&dev, driver->minor_start,
2993 driver->num, driver->name);
2995 driver->major = MAJOR(dev);
2996 driver->minor_start = MINOR(dev);
2999 dev = MKDEV(driver->major, driver->minor_start);
3000 error = register_chrdev_region(dev, driver->num, driver->name);
3008 driver->ttys = (struct tty_struct **)p;
3009 driver->termios = (struct ktermios **)(p + driver->num);
3011 driver->ttys = NULL;
3012 driver->termios = NULL;
3015 cdev_init(&driver->cdev, &tty_fops);
3016 driver->cdev.owner = driver->owner;
3017 error = cdev_add(&driver->cdev, dev, driver->num);
3019 unregister_chrdev_region(dev, driver->num);
3020 driver->ttys = NULL;
3021 driver->termios = NULL;
3026 mutex_lock(&tty_mutex);
3027 list_add(&driver->tty_drivers, &tty_drivers);
3028 mutex_unlock(&tty_mutex);
3030 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3031 for (i = 0; i < driver->num; i++)
3032 tty_register_device(driver, i, NULL);
3034 proc_tty_register_driver(driver);
3035 driver->flags |= TTY_DRIVER_INSTALLED;
3039 EXPORT_SYMBOL(tty_register_driver);
3042 * Called by a tty driver to unregister itself.
3044 int tty_unregister_driver(struct tty_driver *driver)
3048 if (driver->refcount)
3051 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3053 mutex_lock(&tty_mutex);
3054 list_del(&driver->tty_drivers);
3055 mutex_unlock(&tty_mutex);
3059 EXPORT_SYMBOL(tty_unregister_driver);
3061 dev_t tty_devnum(struct tty_struct *tty)
3063 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3065 EXPORT_SYMBOL(tty_devnum);
3067 void proc_clear_tty(struct task_struct *p)
3069 unsigned long flags;
3070 struct tty_struct *tty;
3071 spin_lock_irqsave(&p->sighand->siglock, flags);
3072 tty = p->signal->tty;
3073 p->signal->tty = NULL;
3074 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3078 /* Called under the sighand lock */
3080 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3083 unsigned long flags;
3084 /* We should not have a session or pgrp to put here but.... */
3085 spin_lock_irqsave(&tty->ctrl_lock, flags);
3086 put_pid(tty->session);
3088 tty->pgrp = get_pid(task_pgrp(tsk));
3089 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3090 tty->session = get_pid(task_session(tsk));
3091 if (tsk->signal->tty) {
3092 printk(KERN_DEBUG "tty not NULL!!\n");
3093 tty_kref_put(tsk->signal->tty);
3096 put_pid(tsk->signal->tty_old_pgrp);
3097 tsk->signal->tty = tty_kref_get(tty);
3098 tsk->signal->tty_old_pgrp = NULL;
3101 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3103 spin_lock_irq(&tsk->sighand->siglock);
3104 __proc_set_tty(tsk, tty);
3105 spin_unlock_irq(&tsk->sighand->siglock);
3108 struct tty_struct *get_current_tty(void)
3110 struct tty_struct *tty;
3111 unsigned long flags;
3113 spin_lock_irqsave(¤t->sighand->siglock, flags);
3114 tty = tty_kref_get(current->signal->tty);
3115 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3118 EXPORT_SYMBOL_GPL(get_current_tty);
3120 void tty_default_fops(struct file_operations *fops)
3126 * Initialize the console device. This is called *early*, so
3127 * we can't necessarily depend on lots of kernel help here.
3128 * Just do some early initializations, and do the complex setup
3131 void __init console_init(void)
3135 /* Setup the default TTY line discipline. */
3139 * set up the console device so that later boot sequences can
3140 * inform about problems etc..
3142 call = __con_initcall_start;
3143 while (call < __con_initcall_end) {
3149 static char *tty_devnode(struct device *dev, mode_t *mode)
3153 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3154 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3159 static int __init tty_class_init(void)
3161 tty_class = class_create(THIS_MODULE, "tty");
3162 if (IS_ERR(tty_class))
3163 return PTR_ERR(tty_class);
3164 tty_class->devnode = tty_devnode;
3168 postcore_initcall(tty_class_init);
3170 /* 3/2004 jmc: why do these devices exist? */
3172 static struct cdev tty_cdev, console_cdev;
3175 * Ok, now we can initialize the rest of the tty devices and can count
3176 * on memory allocations, interrupts etc..
3178 int __init tty_init(void)
3180 cdev_init(&tty_cdev, &tty_fops);
3181 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3182 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3183 panic("Couldn't register /dev/tty driver\n");
3184 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3187 cdev_init(&console_cdev, &console_fops);
3188 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3189 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3190 panic("Couldn't register /dev/console driver\n");
3191 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3195 vty_init(&console_fops);