2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
100 #include <asm/system.h>
102 #include <linux/kbd_kern.h>
103 #include <linux/vt_kern.h>
104 #include <linux/selection.h>
106 #include <linux/kmod.h>
107 #include <linux/nsproxy.h>
109 #undef TTY_DEBUG_HANGUP
111 #define TTY_PARANOIA_CHECK 1
112 #define CHECK_TTY_COUNT 1
114 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
115 .c_iflag = ICRNL | IXON,
116 .c_oflag = OPOST | ONLCR,
117 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
118 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
119 ECHOCTL | ECHOKE | IEXTEN,
125 EXPORT_SYMBOL(tty_std_termios);
127 /* This list gets poked at by procfs and various bits of boot up code. This
128 could do with some rationalisation such as pulling the tty proc function
131 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
133 /* Mutex to protect creating and releasing a tty. This is shared with
134 vt.c for deeply disgusting hack reasons */
135 DEFINE_MUTEX(tty_mutex);
136 EXPORT_SYMBOL(tty_mutex);
138 /* Spinlock to protect the tty->tty_files list */
139 DEFINE_SPINLOCK(tty_files_lock);
141 bool __read_mostly console_use_vt = true;
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 int tty_alloc_file(struct file *file)
201 struct tty_file_private *priv;
203 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
207 file->private_data = priv;
212 /* Associate a new file with the tty structure */
213 void tty_add_file(struct tty_struct *tty, struct file *file)
215 struct tty_file_private *priv = file->private_data;
220 spin_lock(&tty_files_lock);
221 list_add(&priv->list, &tty->tty_files);
222 spin_unlock(&tty_files_lock);
226 * tty_free_file - free file->private_data
228 * This shall be used only for fail path handling when tty_add_file was not
231 void tty_free_file(struct file *file)
233 struct tty_file_private *priv = file->private_data;
235 file->private_data = NULL;
239 /* Delete file from its tty */
240 void tty_del_file(struct file *file)
242 struct tty_file_private *priv = file->private_data;
244 spin_lock(&tty_files_lock);
245 list_del(&priv->list);
246 spin_unlock(&tty_files_lock);
251 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
254 * tty_name - return tty naming
255 * @tty: tty structure
256 * @buf: buffer for output
258 * Convert a tty structure into a name. The name reflects the kernel
259 * naming policy and if udev is in use may not reflect user space
264 char *tty_name(struct tty_struct *tty, char *buf)
266 if (!tty) /* Hmm. NULL pointer. That's fun. */
267 strcpy(buf, "NULL tty");
269 strcpy(buf, tty->name);
273 EXPORT_SYMBOL(tty_name);
275 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
278 #ifdef TTY_PARANOIA_CHECK
281 "null TTY for (%d:%d) in %s\n",
282 imajor(inode), iminor(inode), routine);
285 if (tty->magic != TTY_MAGIC) {
287 "bad magic number for tty struct (%d:%d) in %s\n",
288 imajor(inode), iminor(inode), routine);
295 static int check_tty_count(struct tty_struct *tty, const char *routine)
297 #ifdef CHECK_TTY_COUNT
301 spin_lock(&tty_files_lock);
302 list_for_each(p, &tty->tty_files) {
305 spin_unlock(&tty_files_lock);
306 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
307 tty->driver->subtype == PTY_TYPE_SLAVE &&
308 tty->link && tty->link->count)
310 if (tty->count != count) {
311 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
312 "!= #fd's(%d) in %s\n",
313 tty->name, tty->count, count, routine);
321 * get_tty_driver - find device of a tty
322 * @dev_t: device identifier
323 * @index: returns the index of the tty
325 * This routine returns a tty driver structure, given a device number
326 * and also passes back the index number.
328 * Locking: caller must hold tty_mutex
331 static struct tty_driver *get_tty_driver(dev_t device, int *index)
333 struct tty_driver *p;
335 list_for_each_entry(p, &tty_drivers, tty_drivers) {
336 dev_t base = MKDEV(p->major, p->minor_start);
337 if (device < base || device >= base + p->num)
339 *index = device - base;
340 return tty_driver_kref_get(p);
345 #ifdef CONFIG_CONSOLE_POLL
348 * tty_find_polling_driver - find device of a polled tty
349 * @name: name string to match
350 * @line: pointer to resulting tty line nr
352 * This routine returns a tty driver structure, given a name
353 * and the condition that the tty driver is capable of polled
356 struct tty_driver *tty_find_polling_driver(char *name, int *line)
358 struct tty_driver *p, *res = NULL;
363 for (str = name; *str; str++)
364 if ((*str >= '0' && *str <= '9') || *str == ',')
370 tty_line = simple_strtoul(str, &str, 10);
372 mutex_lock(&tty_mutex);
373 /* Search through the tty devices to look for a match */
374 list_for_each_entry(p, &tty_drivers, tty_drivers) {
375 if (strncmp(name, p->name, len) != 0)
383 if (tty_line >= 0 && tty_line < p->num && p->ops &&
384 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
385 res = tty_driver_kref_get(p);
390 mutex_unlock(&tty_mutex);
394 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
398 * tty_check_change - check for POSIX terminal changes
401 * If we try to write to, or set the state of, a terminal and we're
402 * not in the foreground, send a SIGTTOU. If the signal is blocked or
403 * ignored, go ahead and perform the operation. (POSIX 7.2)
408 int tty_check_change(struct tty_struct *tty)
413 if (current->signal->tty != tty)
416 spin_lock_irqsave(&tty->ctrl_lock, flags);
419 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
422 if (task_pgrp(current) == tty->pgrp)
424 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
425 if (is_ignored(SIGTTOU))
427 if (is_current_pgrp_orphaned()) {
431 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
432 set_thread_flag(TIF_SIGPENDING);
437 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
441 EXPORT_SYMBOL(tty_check_change);
443 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
444 size_t count, loff_t *ppos)
449 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
450 size_t count, loff_t *ppos)
455 /* No kernel lock held - none needed ;) */
456 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
458 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
461 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
464 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
467 static long hung_up_tty_compat_ioctl(struct file *file,
468 unsigned int cmd, unsigned long arg)
470 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
473 static const struct file_operations tty_fops = {
478 .unlocked_ioctl = tty_ioctl,
479 .compat_ioctl = tty_compat_ioctl,
481 .release = tty_release,
482 .fasync = tty_fasync,
485 static const struct file_operations console_fops = {
488 .write = redirected_tty_write,
490 .unlocked_ioctl = tty_ioctl,
491 .compat_ioctl = tty_compat_ioctl,
493 .release = tty_release,
494 .fasync = tty_fasync,
497 static const struct file_operations hung_up_tty_fops = {
499 .read = hung_up_tty_read,
500 .write = hung_up_tty_write,
501 .poll = hung_up_tty_poll,
502 .unlocked_ioctl = hung_up_tty_ioctl,
503 .compat_ioctl = hung_up_tty_compat_ioctl,
504 .release = tty_release,
507 static DEFINE_SPINLOCK(redirect_lock);
508 static struct file *redirect;
511 * tty_wakeup - request more data
514 * Internal and external helper for wakeups of tty. This function
515 * informs the line discipline if present that the driver is ready
516 * to receive more output data.
519 void tty_wakeup(struct tty_struct *tty)
521 struct tty_ldisc *ld;
523 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
524 ld = tty_ldisc_ref(tty);
526 if (ld->ops->write_wakeup)
527 ld->ops->write_wakeup(tty);
531 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
534 EXPORT_SYMBOL_GPL(tty_wakeup);
537 * __tty_hangup - actual handler for hangup events
540 * This can be called by the "eventd" kernel thread. That is process
541 * synchronous but doesn't hold any locks, so we need to make sure we
542 * have the appropriate locks for what we're doing.
544 * The hangup event clears any pending redirections onto the hung up
545 * device. It ensures future writes will error and it does the needed
546 * line discipline hangup and signal delivery. The tty object itself
551 * redirect lock for undoing redirection
552 * file list lock for manipulating list of ttys
553 * tty_ldisc_lock from called functions
554 * termios_mutex resetting termios data
555 * tasklist_lock to walk task list for hangup event
556 * ->siglock to protect ->signal/->sighand
558 void __tty_hangup(struct tty_struct *tty)
560 struct file *cons_filp = NULL;
561 struct file *filp, *f = NULL;
562 struct task_struct *p;
563 struct tty_file_private *priv;
564 int closecount = 0, n;
572 spin_lock(&redirect_lock);
573 if (redirect && file_tty(redirect) == tty) {
577 spin_unlock(&redirect_lock);
581 /* some functions below drop BTM, so we need this bit */
582 set_bit(TTY_HUPPING, &tty->flags);
584 /* inuse_filps is protected by the single tty lock,
585 this really needs to change if we want to flush the
586 workqueue with the lock held */
587 check_tty_count(tty, "tty_hangup");
589 spin_lock(&tty_files_lock);
590 /* This breaks for file handles being sent over AF_UNIX sockets ? */
591 list_for_each_entry(priv, &tty->tty_files, list) {
593 if (filp->f_op->write == redirected_tty_write)
595 if (filp->f_op->write != tty_write)
598 __tty_fasync(-1, filp, 0); /* can't block */
599 filp->f_op = &hung_up_tty_fops;
601 spin_unlock(&tty_files_lock);
604 * it drops BTM and thus races with reopen
605 * we protect the race by TTY_HUPPING
607 tty_ldisc_hangup(tty);
609 read_lock(&tasklist_lock);
611 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
612 spin_lock_irq(&p->sighand->siglock);
613 if (p->signal->tty == tty) {
614 p->signal->tty = NULL;
615 /* We defer the dereferences outside fo
619 if (!p->signal->leader) {
620 spin_unlock_irq(&p->sighand->siglock);
623 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
624 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
625 put_pid(p->signal->tty_old_pgrp); /* A noop */
626 spin_lock_irqsave(&tty->ctrl_lock, flags);
628 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
629 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
630 spin_unlock_irq(&p->sighand->siglock);
631 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
633 read_unlock(&tasklist_lock);
635 spin_lock_irqsave(&tty->ctrl_lock, flags);
636 clear_bit(TTY_THROTTLED, &tty->flags);
637 clear_bit(TTY_PUSH, &tty->flags);
638 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
639 put_pid(tty->session);
643 tty->ctrl_status = 0;
644 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
646 /* Account for the p->signal references we killed */
651 * If one of the devices matches a console pointer, we
652 * cannot just call hangup() because that will cause
653 * tty->count and state->count to go out of sync.
654 * So we just call close() the right number of times.
658 for (n = 0; n < closecount; n++)
659 tty->ops->close(tty, cons_filp);
660 } else if (tty->ops->hangup)
661 (tty->ops->hangup)(tty);
663 * We don't want to have driver/ldisc interactions beyond
664 * the ones we did here. The driver layer expects no
665 * calls after ->hangup() from the ldisc side. However we
666 * can't yet guarantee all that.
668 set_bit(TTY_HUPPED, &tty->flags);
669 clear_bit(TTY_HUPPING, &tty->flags);
670 tty_ldisc_enable(tty);
678 static void do_tty_hangup(struct work_struct *work)
680 struct tty_struct *tty =
681 container_of(work, struct tty_struct, hangup_work);
687 * tty_hangup - trigger a hangup event
688 * @tty: tty to hangup
690 * A carrier loss (virtual or otherwise) has occurred on this like
691 * schedule a hangup sequence to run after this event.
694 void tty_hangup(struct tty_struct *tty)
696 #ifdef TTY_DEBUG_HANGUP
698 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
700 schedule_work(&tty->hangup_work);
703 EXPORT_SYMBOL(tty_hangup);
706 * tty_vhangup - process vhangup
707 * @tty: tty to hangup
709 * The user has asked via system call for the terminal to be hung up.
710 * We do this synchronously so that when the syscall returns the process
711 * is complete. That guarantee is necessary for security reasons.
714 void tty_vhangup(struct tty_struct *tty)
716 #ifdef TTY_DEBUG_HANGUP
719 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
724 EXPORT_SYMBOL(tty_vhangup);
728 * tty_vhangup_self - process vhangup for own ctty
730 * Perform a vhangup on the current controlling tty
733 void tty_vhangup_self(void)
735 struct tty_struct *tty;
737 tty = get_current_tty();
745 * tty_hung_up_p - was tty hung up
746 * @filp: file pointer of tty
748 * Return true if the tty has been subject to a vhangup or a carrier
752 int tty_hung_up_p(struct file *filp)
754 return (filp->f_op == &hung_up_tty_fops);
757 EXPORT_SYMBOL(tty_hung_up_p);
759 static void session_clear_tty(struct pid *session)
761 struct task_struct *p;
762 do_each_pid_task(session, PIDTYPE_SID, p) {
764 } while_each_pid_task(session, PIDTYPE_SID, p);
768 * disassociate_ctty - disconnect controlling tty
769 * @on_exit: true if exiting so need to "hang up" the session
771 * This function is typically called only by the session leader, when
772 * it wants to disassociate itself from its controlling tty.
774 * It performs the following functions:
775 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
776 * (2) Clears the tty from being controlling the session
777 * (3) Clears the controlling tty for all processes in the
780 * The argument on_exit is set to 1 if called when a process is
781 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
784 * BTM is taken for hysterical raisins, and held when
785 * called from no_tty().
786 * tty_mutex is taken to protect tty
787 * ->siglock is taken to protect ->signal/->sighand
788 * tasklist_lock is taken to walk process list for sessions
789 * ->siglock is taken to protect ->signal/->sighand
792 void disassociate_ctty(int on_exit)
794 struct tty_struct *tty;
796 if (!current->signal->leader)
799 tty = get_current_tty();
801 struct pid *tty_pgrp = get_pid(tty->pgrp);
803 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
808 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
810 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
813 } else if (on_exit) {
814 struct pid *old_pgrp;
815 spin_lock_irq(¤t->sighand->siglock);
816 old_pgrp = current->signal->tty_old_pgrp;
817 current->signal->tty_old_pgrp = NULL;
818 spin_unlock_irq(¤t->sighand->siglock);
820 kill_pgrp(old_pgrp, SIGHUP, on_exit);
821 kill_pgrp(old_pgrp, SIGCONT, on_exit);
827 spin_lock_irq(¤t->sighand->siglock);
828 put_pid(current->signal->tty_old_pgrp);
829 current->signal->tty_old_pgrp = NULL;
830 spin_unlock_irq(¤t->sighand->siglock);
832 tty = get_current_tty();
835 spin_lock_irqsave(&tty->ctrl_lock, flags);
836 put_pid(tty->session);
840 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
843 #ifdef TTY_DEBUG_HANGUP
844 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
849 /* Now clear signal->tty under the lock */
850 read_lock(&tasklist_lock);
851 session_clear_tty(task_session(current));
852 read_unlock(&tasklist_lock);
857 * no_tty - Ensure the current process does not have a controlling tty
861 struct task_struct *tsk = current;
863 disassociate_ctty(0);
870 * stop_tty - propagate flow control
873 * Perform flow control to the driver. For PTY/TTY pairs we
874 * must also propagate the TIOCKPKT status. May be called
875 * on an already stopped device and will not re-call the driver
878 * This functionality is used by both the line disciplines for
879 * halting incoming flow and by the driver. It may therefore be
880 * called from any context, may be under the tty atomic_write_lock
884 * Uses the tty control lock internally
887 void stop_tty(struct tty_struct *tty)
890 spin_lock_irqsave(&tty->ctrl_lock, flags);
892 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
896 if (tty->link && tty->link->packet) {
897 tty->ctrl_status &= ~TIOCPKT_START;
898 tty->ctrl_status |= TIOCPKT_STOP;
899 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
901 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
903 (tty->ops->stop)(tty);
906 EXPORT_SYMBOL(stop_tty);
909 * start_tty - propagate flow control
912 * Start a tty that has been stopped if at all possible. Perform
913 * any necessary wakeups and propagate the TIOCPKT status. If this
914 * is the tty was previous stopped and is being started then the
915 * driver start method is invoked and the line discipline woken.
921 void start_tty(struct tty_struct *tty)
924 spin_lock_irqsave(&tty->ctrl_lock, flags);
925 if (!tty->stopped || tty->flow_stopped) {
926 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
930 if (tty->link && tty->link->packet) {
931 tty->ctrl_status &= ~TIOCPKT_STOP;
932 tty->ctrl_status |= TIOCPKT_START;
933 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
935 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
937 (tty->ops->start)(tty);
938 /* If we have a running line discipline it may need kicking */
942 EXPORT_SYMBOL(start_tty);
945 * tty_read - read method for tty device files
946 * @file: pointer to tty file
948 * @count: size of user buffer
951 * Perform the read system call function on this terminal device. Checks
952 * for hung up devices before calling the line discipline method.
955 * Locks the line discipline internally while needed. Multiple
956 * read calls may be outstanding in parallel.
959 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
963 struct inode *inode = file->f_path.dentry->d_inode;
964 struct tty_struct *tty = file_tty(file);
965 struct tty_ldisc *ld;
967 if (tty_paranoia_check(tty, inode, "tty_read"))
969 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
972 /* We want to wait for the line discipline to sort out in this
974 ld = tty_ldisc_ref_wait(tty);
976 i = (ld->ops->read)(tty, file, buf, count);
981 inode->i_atime = current_fs_time(inode->i_sb);
985 void tty_write_unlock(struct tty_struct *tty)
986 __releases(&tty->atomic_write_lock)
988 mutex_unlock(&tty->atomic_write_lock);
989 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
992 int tty_write_lock(struct tty_struct *tty, int ndelay)
993 __acquires(&tty->atomic_write_lock)
995 if (!mutex_trylock(&tty->atomic_write_lock)) {
998 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1005 * Split writes up in sane blocksizes to avoid
1006 * denial-of-service type attacks
1008 static inline ssize_t do_tty_write(
1009 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1010 struct tty_struct *tty,
1012 const char __user *buf,
1015 ssize_t ret, written = 0;
1018 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1023 * We chunk up writes into a temporary buffer. This
1024 * simplifies low-level drivers immensely, since they
1025 * don't have locking issues and user mode accesses.
1027 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1030 * The default chunk-size is 2kB, because the NTTY
1031 * layer has problems with bigger chunks. It will
1032 * claim to be able to handle more characters than
1035 * FIXME: This can probably go away now except that 64K chunks
1036 * are too likely to fail unless switched to vmalloc...
1039 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1044 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1045 if (tty->write_cnt < chunk) {
1046 unsigned char *buf_chunk;
1051 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1056 kfree(tty->write_buf);
1057 tty->write_cnt = chunk;
1058 tty->write_buf = buf_chunk;
1061 /* Do the write .. */
1063 size_t size = count;
1067 if (copy_from_user(tty->write_buf, buf, size))
1069 ret = write(tty, file, tty->write_buf, size);
1078 if (signal_pending(current))
1083 struct inode *inode = file->f_path.dentry->d_inode;
1084 inode->i_mtime = current_fs_time(inode->i_sb);
1088 tty_write_unlock(tty);
1093 * tty_write_message - write a message to a certain tty, not just the console.
1094 * @tty: the destination tty_struct
1095 * @msg: the message to write
1097 * This is used for messages that need to be redirected to a specific tty.
1098 * We don't put it into the syslog queue right now maybe in the future if
1101 * We must still hold the BTM and test the CLOSING flag for the moment.
1104 void tty_write_message(struct tty_struct *tty, char *msg)
1107 mutex_lock(&tty->atomic_write_lock);
1109 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1111 tty->ops->write(tty, msg, strlen(msg));
1114 tty_write_unlock(tty);
1121 * tty_write - write method for tty device file
1122 * @file: tty file pointer
1123 * @buf: user data to write
1124 * @count: bytes to write
1127 * Write data to a tty device via the line discipline.
1130 * Locks the line discipline as required
1131 * Writes to the tty driver are serialized by the atomic_write_lock
1132 * and are then processed in chunks to the device. The line discipline
1133 * write method will not be invoked in parallel for each device.
1136 static ssize_t tty_write(struct file *file, const char __user *buf,
1137 size_t count, loff_t *ppos)
1139 struct inode *inode = file->f_path.dentry->d_inode;
1140 struct tty_struct *tty = file_tty(file);
1141 struct tty_ldisc *ld;
1144 if (tty_paranoia_check(tty, inode, "tty_write"))
1146 if (!tty || !tty->ops->write ||
1147 (test_bit(TTY_IO_ERROR, &tty->flags)))
1149 /* Short term debug to catch buggy drivers */
1150 if (tty->ops->write_room == NULL)
1151 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1153 ld = tty_ldisc_ref_wait(tty);
1154 if (!ld->ops->write)
1157 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1158 tty_ldisc_deref(ld);
1162 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1163 size_t count, loff_t *ppos)
1165 struct file *p = NULL;
1167 spin_lock(&redirect_lock);
1172 spin_unlock(&redirect_lock);
1176 res = vfs_write(p, buf, count, &p->f_pos);
1180 return tty_write(file, buf, count, ppos);
1183 static char ptychar[] = "pqrstuvwxyzabcde";
1186 * pty_line_name - generate name for a pty
1187 * @driver: the tty driver in use
1188 * @index: the minor number
1189 * @p: output buffer of at least 6 bytes
1191 * Generate a name from a driver reference and write it to the output
1196 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1198 int i = index + driver->name_base;
1199 /* ->name is initialized to "ttyp", but "tty" is expected */
1200 sprintf(p, "%s%c%x",
1201 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1202 ptychar[i >> 4 & 0xf], i & 0xf);
1206 * tty_line_name - generate name for a tty
1207 * @driver: the tty driver in use
1208 * @index: the minor number
1209 * @p: output buffer of at least 7 bytes
1211 * Generate a name from a driver reference and write it to the output
1216 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1218 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1222 * tty_driver_lookup_tty() - find an existing tty, if any
1223 * @driver: the driver for the tty
1224 * @idx: the minor number
1226 * Return the tty, if found or ERR_PTR() otherwise.
1228 * Locking: tty_mutex must be held. If tty is found, the mutex must
1229 * be held until the 'fast-open' is also done. Will change once we
1230 * have refcounting in the driver and per driver locking
1232 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1233 struct inode *inode, int idx)
1235 struct tty_struct *tty;
1237 if (driver->ops->lookup)
1238 return driver->ops->lookup(driver, inode, idx);
1240 tty = driver->ttys[idx];
1245 * tty_init_termios - helper for termios setup
1246 * @tty: the tty to set up
1248 * Initialise the termios structures for this tty. Thus runs under
1249 * the tty_mutex currently so we can be relaxed about ordering.
1252 int tty_init_termios(struct tty_struct *tty)
1254 struct ktermios *tp;
1255 int idx = tty->index;
1257 tp = tty->driver->termios[idx];
1259 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1262 memcpy(tp, &tty->driver->init_termios,
1263 sizeof(struct ktermios));
1264 tty->driver->termios[idx] = tp;
1267 tty->termios_locked = tp + 1;
1269 /* Compatibility until drivers always set this */
1270 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1271 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1274 EXPORT_SYMBOL_GPL(tty_init_termios);
1277 * tty_driver_install_tty() - install a tty entry in the driver
1278 * @driver: the driver for the tty
1281 * Install a tty object into the driver tables. The tty->index field
1282 * will be set by the time this is called. This method is responsible
1283 * for ensuring any need additional structures are allocated and
1286 * Locking: tty_mutex for now
1288 static int tty_driver_install_tty(struct tty_driver *driver,
1289 struct tty_struct *tty)
1291 int idx = tty->index;
1294 if (driver->ops->install) {
1295 ret = driver->ops->install(driver, tty);
1299 if (tty_init_termios(tty) == 0) {
1300 tty_driver_kref_get(driver);
1302 driver->ttys[idx] = tty;
1309 * tty_driver_remove_tty() - remove a tty from the driver tables
1310 * @driver: the driver for the tty
1311 * @idx: the minor number
1313 * Remvoe a tty object from the driver tables. The tty->index field
1314 * will be set by the time this is called.
1316 * Locking: tty_mutex for now
1318 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1320 if (driver->ops->remove)
1321 driver->ops->remove(driver, tty);
1323 driver->ttys[tty->index] = NULL;
1327 * tty_reopen() - fast re-open of an open tty
1328 * @tty - the tty to open
1330 * Return 0 on success, -errno on error.
1332 * Locking: tty_mutex must be held from the time the tty was found
1333 * till this open completes.
1335 static int tty_reopen(struct tty_struct *tty)
1337 struct tty_driver *driver = tty->driver;
1339 if (test_bit(TTY_CLOSING, &tty->flags) ||
1340 test_bit(TTY_HUPPING, &tty->flags) ||
1341 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1344 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1345 driver->subtype == PTY_TYPE_MASTER) {
1347 * special case for PTY masters: only one open permitted,
1348 * and the slave side open count is incremented as well.
1356 tty->driver = driver; /* N.B. why do this every time?? */
1358 mutex_lock(&tty->ldisc_mutex);
1359 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1360 mutex_unlock(&tty->ldisc_mutex);
1366 * tty_init_dev - initialise a tty device
1367 * @driver: tty driver we are opening a device on
1368 * @idx: device index
1369 * @ret_tty: returned tty structure
1370 * @first_ok: ok to open a new device (used by ptmx)
1372 * Prepare a tty device. This may not be a "new" clean device but
1373 * could also be an active device. The pty drivers require special
1374 * handling because of this.
1377 * The function is called under the tty_mutex, which
1378 * protects us from the tty struct or driver itself going away.
1380 * On exit the tty device has the line discipline attached and
1381 * a reference count of 1. If a pair was created for pty/tty use
1382 * and the other was a pty master then it too has a reference count of 1.
1384 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1385 * failed open. The new code protects the open with a mutex, so it's
1386 * really quite straightforward. The mutex locking can probably be
1387 * relaxed for the (most common) case of reopening a tty.
1390 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1393 struct tty_struct *tty;
1396 /* Check if pty master is being opened multiple times */
1397 if (driver->subtype == PTY_TYPE_MASTER &&
1398 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1399 return ERR_PTR(-EIO);
1403 * First time open is complex, especially for PTY devices.
1404 * This code guarantees that either everything succeeds and the
1405 * TTY is ready for operation, or else the table slots are vacated
1406 * and the allocated memory released. (Except that the termios
1407 * and locked termios may be retained.)
1410 if (!try_module_get(driver->owner))
1411 return ERR_PTR(-ENODEV);
1413 tty = alloc_tty_struct();
1416 goto err_module_put;
1418 initialize_tty_struct(tty, driver, idx);
1420 retval = tty_driver_install_tty(driver, tty);
1422 goto err_deinit_tty;
1425 * Structures all installed ... call the ldisc open routines.
1426 * If we fail here just call release_tty to clean up. No need
1427 * to decrement the use counts, as release_tty doesn't care.
1429 retval = tty_ldisc_setup(tty, tty->link);
1431 goto err_release_tty;
1435 deinitialize_tty_struct(tty);
1436 free_tty_struct(tty);
1438 module_put(driver->owner);
1439 return ERR_PTR(retval);
1441 /* call the tty release_tty routine to clean out this slot */
1443 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1444 "clearing slot %d\n", idx);
1445 release_tty(tty, idx);
1446 return ERR_PTR(retval);
1449 void tty_free_termios(struct tty_struct *tty)
1451 struct ktermios *tp;
1452 int idx = tty->index;
1453 /* Kill this flag and push into drivers for locking etc */
1454 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1455 /* FIXME: Locking on ->termios array */
1457 tty->driver->termios[idx] = NULL;
1461 EXPORT_SYMBOL(tty_free_termios);
1463 void tty_shutdown(struct tty_struct *tty)
1465 tty_driver_remove_tty(tty->driver, tty);
1466 tty_free_termios(tty);
1468 EXPORT_SYMBOL(tty_shutdown);
1471 * release_one_tty - release tty structure memory
1472 * @kref: kref of tty we are obliterating
1474 * Releases memory associated with a tty structure, and clears out the
1475 * driver table slots. This function is called when a device is no longer
1476 * in use. It also gets called when setup of a device fails.
1479 * tty_mutex - sometimes only
1480 * takes the file list lock internally when working on the list
1481 * of ttys that the driver keeps.
1483 * This method gets called from a work queue so that the driver private
1484 * cleanup ops can sleep (needed for USB at least)
1486 static void release_one_tty(struct work_struct *work)
1488 struct tty_struct *tty =
1489 container_of(work, struct tty_struct, hangup_work);
1490 struct tty_driver *driver = tty->driver;
1492 if (tty->ops->cleanup)
1493 tty->ops->cleanup(tty);
1496 tty_driver_kref_put(driver);
1497 module_put(driver->owner);
1499 spin_lock(&tty_files_lock);
1500 list_del_init(&tty->tty_files);
1501 spin_unlock(&tty_files_lock);
1504 put_pid(tty->session);
1505 free_tty_struct(tty);
1508 static void queue_release_one_tty(struct kref *kref)
1510 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1512 if (tty->ops->shutdown)
1513 tty->ops->shutdown(tty);
1517 /* The hangup queue is now free so we can reuse it rather than
1518 waste a chunk of memory for each port */
1519 INIT_WORK(&tty->hangup_work, release_one_tty);
1520 schedule_work(&tty->hangup_work);
1524 * tty_kref_put - release a tty kref
1527 * Release a reference to a tty device and if need be let the kref
1528 * layer destruct the object for us
1531 void tty_kref_put(struct tty_struct *tty)
1534 kref_put(&tty->kref, queue_release_one_tty);
1536 EXPORT_SYMBOL(tty_kref_put);
1539 * release_tty - release tty structure memory
1541 * Release both @tty and a possible linked partner (think pty pair),
1542 * and decrement the refcount of the backing module.
1545 * tty_mutex - sometimes only
1546 * takes the file list lock internally when working on the list
1547 * of ttys that the driver keeps.
1548 * FIXME: should we require tty_mutex is held here ??
1551 static void release_tty(struct tty_struct *tty, int idx)
1553 /* This should always be true but check for the moment */
1554 WARN_ON(tty->index != idx);
1557 tty_kref_put(tty->link);
1562 * tty_release_checks - check a tty before real release
1563 * @tty: tty to check
1564 * @o_tty: link of @tty (if any)
1565 * @idx: index of the tty
1567 * Performs some paranoid checking before true release of the @tty.
1568 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1570 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1573 #ifdef TTY_PARANOIA_CHECK
1574 if (idx < 0 || idx >= tty->driver->num) {
1575 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1576 __func__, tty->name);
1580 /* not much to check for devpts */
1581 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1584 if (tty != tty->driver->ttys[idx]) {
1585 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1586 __func__, idx, tty->name);
1589 if (tty->termios != tty->driver->termios[idx]) {
1590 printk(KERN_DEBUG "%s: driver.termios[%d] not termios for (%s)\n",
1591 __func__, idx, tty->name);
1594 if (tty->driver->other) {
1595 if (o_tty != tty->driver->other->ttys[idx]) {
1596 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1597 __func__, idx, tty->name);
1600 if (o_tty->termios != tty->driver->other->termios[idx]) {
1601 printk(KERN_DEBUG "%s: other->termios[%d] not o_termios for (%s)\n",
1602 __func__, idx, tty->name);
1605 if (o_tty->link != tty) {
1606 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1615 * tty_release - vfs callback for close
1616 * @inode: inode of tty
1617 * @filp: file pointer for handle to tty
1619 * Called the last time each file handle is closed that references
1620 * this tty. There may however be several such references.
1623 * Takes bkl. See tty_release_dev
1625 * Even releasing the tty structures is a tricky business.. We have
1626 * to be very careful that the structures are all released at the
1627 * same time, as interrupts might otherwise get the wrong pointers.
1629 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1630 * lead to double frees or releasing memory still in use.
1633 int tty_release(struct inode *inode, struct file *filp)
1635 struct tty_struct *tty = file_tty(filp);
1636 struct tty_struct *o_tty;
1637 int pty_master, tty_closing, o_tty_closing, do_sleep;
1642 if (tty_paranoia_check(tty, inode, __func__))
1646 check_tty_count(tty, __func__);
1648 __tty_fasync(-1, filp, 0);
1651 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1652 tty->driver->subtype == PTY_TYPE_MASTER);
1653 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1656 if (tty_release_checks(tty, o_tty, idx)) {
1661 #ifdef TTY_DEBUG_HANGUP
1662 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1663 tty_name(tty, buf), tty->count);
1666 if (tty->ops->close)
1667 tty->ops->close(tty, filp);
1671 * Sanity check: if tty->count is going to zero, there shouldn't be
1672 * any waiters on tty->read_wait or tty->write_wait. We test the
1673 * wait queues and kick everyone out _before_ actually starting to
1674 * close. This ensures that we won't block while releasing the tty
1677 * The test for the o_tty closing is necessary, since the master and
1678 * slave sides may close in any order. If the slave side closes out
1679 * first, its count will be one, since the master side holds an open.
1680 * Thus this test wouldn't be triggered at the time the slave closes,
1683 * Note that it's possible for the tty to be opened again while we're
1684 * flushing out waiters. By recalculating the closing flags before
1685 * each iteration we avoid any problems.
1688 /* Guard against races with tty->count changes elsewhere and
1689 opens on /dev/tty */
1691 mutex_lock(&tty_mutex);
1693 tty_closing = tty->count <= 1;
1694 o_tty_closing = o_tty &&
1695 (o_tty->count <= (pty_master ? 1 : 0));
1699 if (waitqueue_active(&tty->read_wait)) {
1700 wake_up_poll(&tty->read_wait, POLLIN);
1703 if (waitqueue_active(&tty->write_wait)) {
1704 wake_up_poll(&tty->write_wait, POLLOUT);
1708 if (o_tty_closing) {
1709 if (waitqueue_active(&o_tty->read_wait)) {
1710 wake_up_poll(&o_tty->read_wait, POLLIN);
1713 if (waitqueue_active(&o_tty->write_wait)) {
1714 wake_up_poll(&o_tty->write_wait, POLLOUT);
1721 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1722 __func__, tty_name(tty, buf));
1724 mutex_unlock(&tty_mutex);
1729 * The closing flags are now consistent with the open counts on
1730 * both sides, and we've completed the last operation that could
1731 * block, so it's safe to proceed with closing.
1734 if (--o_tty->count < 0) {
1735 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1736 __func__, o_tty->count, tty_name(o_tty, buf));
1740 if (--tty->count < 0) {
1741 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1742 __func__, tty->count, tty_name(tty, buf));
1747 * We've decremented tty->count, so we need to remove this file
1748 * descriptor off the tty->tty_files list; this serves two
1750 * - check_tty_count sees the correct number of file descriptors
1751 * associated with this tty.
1752 * - do_tty_hangup no longer sees this file descriptor as
1753 * something that needs to be handled for hangups.
1758 * Perform some housekeeping before deciding whether to return.
1760 * Set the TTY_CLOSING flag if this was the last open. In the
1761 * case of a pty we may have to wait around for the other side
1762 * to close, and TTY_CLOSING makes sure we can't be reopened.
1765 set_bit(TTY_CLOSING, &tty->flags);
1767 set_bit(TTY_CLOSING, &o_tty->flags);
1770 * If _either_ side is closing, make sure there aren't any
1771 * processes that still think tty or o_tty is their controlling
1774 if (tty_closing || o_tty_closing) {
1775 read_lock(&tasklist_lock);
1776 session_clear_tty(tty->session);
1778 session_clear_tty(o_tty->session);
1779 read_unlock(&tasklist_lock);
1782 mutex_unlock(&tty_mutex);
1784 /* check whether both sides are closing ... */
1785 if (!tty_closing || (o_tty && !o_tty_closing)) {
1790 #ifdef TTY_DEBUG_HANGUP
1791 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1794 * Ask the line discipline code to release its structures
1796 tty_ldisc_release(tty, o_tty);
1798 * The release_tty function takes care of the details of clearing
1799 * the slots and preserving the termios structure.
1801 release_tty(tty, idx);
1803 /* Make this pty number available for reallocation */
1805 devpts_kill_index(inode, idx);
1811 * tty_open_current_tty - get tty of current task for open
1812 * @device: device number
1813 * @filp: file pointer to tty
1814 * @return: tty of the current task iff @device is /dev/tty
1816 * We cannot return driver and index like for the other nodes because
1817 * devpts will not work then. It expects inodes to be from devpts FS.
1819 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1821 struct tty_struct *tty;
1823 if (device != MKDEV(TTYAUX_MAJOR, 0))
1826 tty = get_current_tty();
1828 return ERR_PTR(-ENXIO);
1830 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1833 /* FIXME: we put a reference and return a TTY! */
1838 * tty_lookup_driver - lookup a tty driver for a given device file
1839 * @device: device number
1840 * @filp: file pointer to tty
1841 * @noctty: set if the device should not become a controlling tty
1842 * @index: index for the device in the @return driver
1843 * @return: driver for this inode (with increased refcount)
1845 * If @return is not erroneous, the caller is responsible to decrement the
1846 * refcount by tty_driver_kref_put.
1848 * Locking: tty_mutex protects get_tty_driver
1850 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1851 int *noctty, int *index)
1853 struct tty_driver *driver;
1857 case MKDEV(TTY_MAJOR, 0): {
1858 extern struct tty_driver *console_driver;
1860 if (!console_use_vt)
1861 return get_tty_driver(device, index)
1862 ?: ERR_PTR(-ENODEV);
1863 driver = tty_driver_kref_get(console_driver);
1864 *index = fg_console;
1869 case MKDEV(TTYAUX_MAJOR, 1): {
1870 struct tty_driver *console_driver = console_device(index);
1871 if (console_driver) {
1872 driver = tty_driver_kref_get(console_driver);
1874 /* Don't let /dev/console block */
1875 filp->f_flags |= O_NONBLOCK;
1880 return ERR_PTR(-ENODEV);
1883 driver = get_tty_driver(device, index);
1885 return ERR_PTR(-ENODEV);
1892 * tty_open - open a tty device
1893 * @inode: inode of device file
1894 * @filp: file pointer to tty
1896 * tty_open and tty_release keep up the tty count that contains the
1897 * number of opens done on a tty. We cannot use the inode-count, as
1898 * different inodes might point to the same tty.
1900 * Open-counting is needed for pty masters, as well as for keeping
1901 * track of serial lines: DTR is dropped when the last close happens.
1902 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1904 * The termios state of a pty is reset on first open so that
1905 * settings don't persist across reuse.
1907 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1908 * tty->count should protect the rest.
1909 * ->siglock protects ->signal/->sighand
1912 static int tty_open(struct inode *inode, struct file *filp)
1914 struct tty_struct *tty;
1916 struct tty_driver *driver = NULL;
1918 dev_t device = inode->i_rdev;
1919 unsigned saved_flags = filp->f_flags;
1921 nonseekable_open(inode, filp);
1924 retval = tty_alloc_file(filp);
1928 noctty = filp->f_flags & O_NOCTTY;
1932 mutex_lock(&tty_mutex);
1935 tty = tty_open_current_tty(device, filp);
1937 retval = PTR_ERR(tty);
1940 driver = tty_lookup_driver(device, filp, &noctty, &index);
1941 if (IS_ERR(driver)) {
1942 retval = PTR_ERR(driver);
1946 /* check whether we're reopening an existing tty */
1947 tty = tty_driver_lookup_tty(driver, inode, index);
1949 retval = PTR_ERR(tty);
1955 retval = tty_reopen(tty);
1957 tty = ERR_PTR(retval);
1959 tty = tty_init_dev(driver, index, 0);
1961 mutex_unlock(&tty_mutex);
1963 tty_driver_kref_put(driver);
1966 retval = PTR_ERR(tty);
1970 tty_add_file(tty, filp);
1972 check_tty_count(tty, __func__);
1973 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1974 tty->driver->subtype == PTY_TYPE_MASTER)
1976 #ifdef TTY_DEBUG_HANGUP
1977 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1980 retval = tty->ops->open(tty, filp);
1983 filp->f_flags = saved_flags;
1985 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1986 !capable(CAP_SYS_ADMIN))
1990 #ifdef TTY_DEBUG_HANGUP
1991 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
1994 tty_unlock(); /* need to call tty_release without BTM */
1995 tty_release(inode, filp);
1996 if (retval != -ERESTARTSYS)
1999 if (signal_pending(current))
2004 * Need to reset f_op in case a hangup happened.
2007 if (filp->f_op == &hung_up_tty_fops)
2008 filp->f_op = &tty_fops;
2015 mutex_lock(&tty_mutex);
2017 spin_lock_irq(¤t->sighand->siglock);
2019 current->signal->leader &&
2020 !current->signal->tty &&
2021 tty->session == NULL)
2022 __proc_set_tty(current, tty);
2023 spin_unlock_irq(¤t->sighand->siglock);
2025 mutex_unlock(&tty_mutex);
2029 mutex_unlock(&tty_mutex);
2030 /* after locks to avoid deadlock */
2031 if (!IS_ERR_OR_NULL(driver))
2032 tty_driver_kref_put(driver);
2034 tty_free_file(filp);
2041 * tty_poll - check tty status
2042 * @filp: file being polled
2043 * @wait: poll wait structures to update
2045 * Call the line discipline polling method to obtain the poll
2046 * status of the device.
2048 * Locking: locks called line discipline but ldisc poll method
2049 * may be re-entered freely by other callers.
2052 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2054 struct tty_struct *tty = file_tty(filp);
2055 struct tty_ldisc *ld;
2058 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2061 ld = tty_ldisc_ref_wait(tty);
2063 ret = (ld->ops->poll)(tty, filp, wait);
2064 tty_ldisc_deref(ld);
2068 static int __tty_fasync(int fd, struct file *filp, int on)
2070 struct tty_struct *tty = file_tty(filp);
2071 unsigned long flags;
2074 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2077 retval = fasync_helper(fd, filp, on, &tty->fasync);
2084 if (!waitqueue_active(&tty->read_wait))
2085 tty->minimum_to_wake = 1;
2086 spin_lock_irqsave(&tty->ctrl_lock, flags);
2089 type = PIDTYPE_PGID;
2091 pid = task_pid(current);
2095 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2096 retval = __f_setown(filp, pid, type, 0);
2101 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2102 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2109 static int tty_fasync(int fd, struct file *filp, int on)
2113 retval = __tty_fasync(fd, filp, on);
2119 * tiocsti - fake input character
2120 * @tty: tty to fake input into
2121 * @p: pointer to character
2123 * Fake input to a tty device. Does the necessary locking and
2126 * FIXME: does not honour flow control ??
2129 * Called functions take tty_ldisc_lock
2130 * current->signal->tty check is safe without locks
2132 * FIXME: may race normal receive processing
2135 static int tiocsti(struct tty_struct *tty, char __user *p)
2138 struct tty_ldisc *ld;
2140 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2142 if (get_user(ch, p))
2144 tty_audit_tiocsti(tty, ch);
2145 ld = tty_ldisc_ref_wait(tty);
2146 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2147 tty_ldisc_deref(ld);
2152 * tiocgwinsz - implement window query ioctl
2154 * @arg: user buffer for result
2156 * Copies the kernel idea of the window size into the user buffer.
2158 * Locking: tty->termios_mutex is taken to ensure the winsize data
2162 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2166 mutex_lock(&tty->termios_mutex);
2167 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2168 mutex_unlock(&tty->termios_mutex);
2170 return err ? -EFAULT: 0;
2174 * tty_do_resize - resize event
2175 * @tty: tty being resized
2176 * @rows: rows (character)
2177 * @cols: cols (character)
2179 * Update the termios variables and send the necessary signals to
2180 * peform a terminal resize correctly
2183 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2186 unsigned long flags;
2189 mutex_lock(&tty->termios_mutex);
2190 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2192 /* Get the PID values and reference them so we can
2193 avoid holding the tty ctrl lock while sending signals */
2194 spin_lock_irqsave(&tty->ctrl_lock, flags);
2195 pgrp = get_pid(tty->pgrp);
2196 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2199 kill_pgrp(pgrp, SIGWINCH, 1);
2204 mutex_unlock(&tty->termios_mutex);
2209 * tiocswinsz - implement window size set ioctl
2210 * @tty; tty side of tty
2211 * @arg: user buffer for result
2213 * Copies the user idea of the window size to the kernel. Traditionally
2214 * this is just advisory information but for the Linux console it
2215 * actually has driver level meaning and triggers a VC resize.
2218 * Driver dependent. The default do_resize method takes the
2219 * tty termios mutex and ctrl_lock. The console takes its own lock
2220 * then calls into the default method.
2223 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2225 struct winsize tmp_ws;
2226 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2229 if (tty->ops->resize)
2230 return tty->ops->resize(tty, &tmp_ws);
2232 return tty_do_resize(tty, &tmp_ws);
2236 * tioccons - allow admin to move logical console
2237 * @file: the file to become console
2239 * Allow the administrator to move the redirected console device
2241 * Locking: uses redirect_lock to guard the redirect information
2244 static int tioccons(struct file *file)
2246 if (!capable(CAP_SYS_ADMIN))
2248 if (file->f_op->write == redirected_tty_write) {
2250 spin_lock(&redirect_lock);
2253 spin_unlock(&redirect_lock);
2258 spin_lock(&redirect_lock);
2260 spin_unlock(&redirect_lock);
2265 spin_unlock(&redirect_lock);
2270 * fionbio - non blocking ioctl
2271 * @file: file to set blocking value
2272 * @p: user parameter
2274 * Historical tty interfaces had a blocking control ioctl before
2275 * the generic functionality existed. This piece of history is preserved
2276 * in the expected tty API of posix OS's.
2278 * Locking: none, the open file handle ensures it won't go away.
2281 static int fionbio(struct file *file, int __user *p)
2285 if (get_user(nonblock, p))
2288 spin_lock(&file->f_lock);
2290 file->f_flags |= O_NONBLOCK;
2292 file->f_flags &= ~O_NONBLOCK;
2293 spin_unlock(&file->f_lock);
2298 * tiocsctty - set controlling tty
2299 * @tty: tty structure
2300 * @arg: user argument
2302 * This ioctl is used to manage job control. It permits a session
2303 * leader to set this tty as the controlling tty for the session.
2306 * Takes tty_mutex() to protect tty instance
2307 * Takes tasklist_lock internally to walk sessions
2308 * Takes ->siglock() when updating signal->tty
2311 static int tiocsctty(struct tty_struct *tty, int arg)
2314 if (current->signal->leader && (task_session(current) == tty->session))
2317 mutex_lock(&tty_mutex);
2319 * The process must be a session leader and
2320 * not have a controlling tty already.
2322 if (!current->signal->leader || current->signal->tty) {
2329 * This tty is already the controlling
2330 * tty for another session group!
2332 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2336 read_lock(&tasklist_lock);
2337 session_clear_tty(tty->session);
2338 read_unlock(&tasklist_lock);
2344 proc_set_tty(current, tty);
2346 mutex_unlock(&tty_mutex);
2351 * tty_get_pgrp - return a ref counted pgrp pid
2354 * Returns a refcounted instance of the pid struct for the process
2355 * group controlling the tty.
2358 struct pid *tty_get_pgrp(struct tty_struct *tty)
2360 unsigned long flags;
2363 spin_lock_irqsave(&tty->ctrl_lock, flags);
2364 pgrp = get_pid(tty->pgrp);
2365 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2369 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2372 * tiocgpgrp - get process group
2373 * @tty: tty passed by user
2374 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2377 * Obtain the process group of the tty. If there is no process group
2380 * Locking: none. Reference to current->signal->tty is safe.
2383 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2388 * (tty == real_tty) is a cheap way of
2389 * testing if the tty is NOT a master pty.
2391 if (tty == real_tty && current->signal->tty != real_tty)
2393 pid = tty_get_pgrp(real_tty);
2394 ret = put_user(pid_vnr(pid), p);
2400 * tiocspgrp - attempt to set process group
2401 * @tty: tty passed by user
2402 * @real_tty: tty side device matching tty passed by user
2405 * Set the process group of the tty to the session passed. Only
2406 * permitted where the tty session is our session.
2408 * Locking: RCU, ctrl lock
2411 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2415 int retval = tty_check_change(real_tty);
2416 unsigned long flags;
2422 if (!current->signal->tty ||
2423 (current->signal->tty != real_tty) ||
2424 (real_tty->session != task_session(current)))
2426 if (get_user(pgrp_nr, p))
2431 pgrp = find_vpid(pgrp_nr);
2436 if (session_of_pgrp(pgrp) != task_session(current))
2439 spin_lock_irqsave(&tty->ctrl_lock, flags);
2440 put_pid(real_tty->pgrp);
2441 real_tty->pgrp = get_pid(pgrp);
2442 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2449 * tiocgsid - get session id
2450 * @tty: tty passed by user
2451 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2452 * @p: pointer to returned session id
2454 * Obtain the session id of the tty. If there is no session
2457 * Locking: none. Reference to current->signal->tty is safe.
2460 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2463 * (tty == real_tty) is a cheap way of
2464 * testing if the tty is NOT a master pty.
2466 if (tty == real_tty && current->signal->tty != real_tty)
2468 if (!real_tty->session)
2470 return put_user(pid_vnr(real_tty->session), p);
2474 * tiocsetd - set line discipline
2476 * @p: pointer to user data
2478 * Set the line discipline according to user request.
2480 * Locking: see tty_set_ldisc, this function is just a helper
2483 static int tiocsetd(struct tty_struct *tty, int __user *p)
2488 if (get_user(ldisc, p))
2491 ret = tty_set_ldisc(tty, ldisc);
2497 * send_break - performed time break
2498 * @tty: device to break on
2499 * @duration: timeout in mS
2501 * Perform a timed break on hardware that lacks its own driver level
2502 * timed break functionality.
2505 * atomic_write_lock serializes
2509 static int send_break(struct tty_struct *tty, unsigned int duration)
2513 if (tty->ops->break_ctl == NULL)
2516 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2517 retval = tty->ops->break_ctl(tty, duration);
2519 /* Do the work ourselves */
2520 if (tty_write_lock(tty, 0) < 0)
2522 retval = tty->ops->break_ctl(tty, -1);
2525 if (!signal_pending(current))
2526 msleep_interruptible(duration);
2527 retval = tty->ops->break_ctl(tty, 0);
2529 tty_write_unlock(tty);
2530 if (signal_pending(current))
2537 * tty_tiocmget - get modem status
2539 * @file: user file pointer
2540 * @p: pointer to result
2542 * Obtain the modem status bits from the tty driver if the feature
2543 * is supported. Return -EINVAL if it is not available.
2545 * Locking: none (up to the driver)
2548 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2550 int retval = -EINVAL;
2552 if (tty->ops->tiocmget) {
2553 retval = tty->ops->tiocmget(tty);
2556 retval = put_user(retval, p);
2562 * tty_tiocmset - set modem status
2564 * @cmd: command - clear bits, set bits or set all
2565 * @p: pointer to desired bits
2567 * Set the modem status bits from the tty driver if the feature
2568 * is supported. Return -EINVAL if it is not available.
2570 * Locking: none (up to the driver)
2573 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2577 unsigned int set, clear, val;
2579 if (tty->ops->tiocmset == NULL)
2582 retval = get_user(val, p);
2598 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2599 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2600 return tty->ops->tiocmset(tty, set, clear);
2603 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2605 int retval = -EINVAL;
2606 struct serial_icounter_struct icount;
2607 memset(&icount, 0, sizeof(icount));
2608 if (tty->ops->get_icount)
2609 retval = tty->ops->get_icount(tty, &icount);
2612 if (copy_to_user(arg, &icount, sizeof(icount)))
2617 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2619 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2620 tty->driver->subtype == PTY_TYPE_MASTER)
2624 EXPORT_SYMBOL(tty_pair_get_tty);
2626 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2628 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2629 tty->driver->subtype == PTY_TYPE_MASTER)
2633 EXPORT_SYMBOL(tty_pair_get_pty);
2636 * Split this up, as gcc can choke on it otherwise..
2638 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2640 struct tty_struct *tty = file_tty(file);
2641 struct tty_struct *real_tty;
2642 void __user *p = (void __user *)arg;
2644 struct tty_ldisc *ld;
2645 struct inode *inode = file->f_dentry->d_inode;
2647 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2650 real_tty = tty_pair_get_tty(tty);
2653 * Factor out some common prep work
2661 retval = tty_check_change(tty);
2664 if (cmd != TIOCCBRK) {
2665 tty_wait_until_sent(tty, 0);
2666 if (signal_pending(current))
2677 return tiocsti(tty, p);
2679 return tiocgwinsz(real_tty, p);
2681 return tiocswinsz(real_tty, p);
2683 return real_tty != tty ? -EINVAL : tioccons(file);
2685 return fionbio(file, p);
2687 set_bit(TTY_EXCLUSIVE, &tty->flags);
2690 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2693 if (current->signal->tty != tty)
2698 return tiocsctty(tty, arg);
2700 return tiocgpgrp(tty, real_tty, p);
2702 return tiocspgrp(tty, real_tty, p);
2704 return tiocgsid(tty, real_tty, p);
2706 return put_user(tty->ldisc->ops->num, (int __user *)p);
2708 return tiocsetd(tty, p);
2710 if (!capable(CAP_SYS_ADMIN))
2716 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2717 return put_user(ret, (unsigned int __user *)p);
2722 case TIOCSBRK: /* Turn break on, unconditionally */
2723 if (tty->ops->break_ctl)
2724 return tty->ops->break_ctl(tty, -1);
2726 case TIOCCBRK: /* Turn break off, unconditionally */
2727 if (tty->ops->break_ctl)
2728 return tty->ops->break_ctl(tty, 0);
2730 case TCSBRK: /* SVID version: non-zero arg --> no break */
2731 /* non-zero arg means wait for all output data
2732 * to be sent (performed above) but don't send break.
2733 * This is used by the tcdrain() termios function.
2736 return send_break(tty, 250);
2738 case TCSBRKP: /* support for POSIX tcsendbreak() */
2739 return send_break(tty, arg ? arg*100 : 250);
2742 return tty_tiocmget(tty, p);
2746 return tty_tiocmset(tty, cmd, p);
2748 retval = tty_tiocgicount(tty, p);
2749 /* For the moment allow fall through to the old method */
2750 if (retval != -EINVAL)
2757 /* flush tty buffer and allow ldisc to process ioctl */
2758 tty_buffer_flush(tty);
2763 if (tty->ops->ioctl) {
2764 retval = (tty->ops->ioctl)(tty, cmd, arg);
2765 if (retval != -ENOIOCTLCMD)
2768 ld = tty_ldisc_ref_wait(tty);
2770 if (ld->ops->ioctl) {
2771 retval = ld->ops->ioctl(tty, file, cmd, arg);
2772 if (retval == -ENOIOCTLCMD)
2775 tty_ldisc_deref(ld);
2779 #ifdef CONFIG_COMPAT
2780 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2783 struct inode *inode = file->f_dentry->d_inode;
2784 struct tty_struct *tty = file_tty(file);
2785 struct tty_ldisc *ld;
2786 int retval = -ENOIOCTLCMD;
2788 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2791 if (tty->ops->compat_ioctl) {
2792 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2793 if (retval != -ENOIOCTLCMD)
2797 ld = tty_ldisc_ref_wait(tty);
2798 if (ld->ops->compat_ioctl)
2799 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2801 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2802 tty_ldisc_deref(ld);
2809 * This implements the "Secure Attention Key" --- the idea is to
2810 * prevent trojan horses by killing all processes associated with this
2811 * tty when the user hits the "Secure Attention Key". Required for
2812 * super-paranoid applications --- see the Orange Book for more details.
2814 * This code could be nicer; ideally it should send a HUP, wait a few
2815 * seconds, then send a INT, and then a KILL signal. But you then
2816 * have to coordinate with the init process, since all processes associated
2817 * with the current tty must be dead before the new getty is allowed
2820 * Now, if it would be correct ;-/ The current code has a nasty hole -
2821 * it doesn't catch files in flight. We may send the descriptor to ourselves
2822 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2824 * Nasty bug: do_SAK is being called in interrupt context. This can
2825 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2827 void __do_SAK(struct tty_struct *tty)
2832 struct task_struct *g, *p;
2833 struct pid *session;
2836 struct fdtable *fdt;
2840 session = tty->session;
2842 tty_ldisc_flush(tty);
2844 tty_driver_flush_buffer(tty);
2846 read_lock(&tasklist_lock);
2847 /* Kill the entire session */
2848 do_each_pid_task(session, PIDTYPE_SID, p) {
2849 printk(KERN_NOTICE "SAK: killed process %d"
2850 " (%s): task_session(p)==tty->session\n",
2851 task_pid_nr(p), p->comm);
2852 send_sig(SIGKILL, p, 1);
2853 } while_each_pid_task(session, PIDTYPE_SID, p);
2854 /* Now kill any processes that happen to have the
2857 do_each_thread(g, p) {
2858 if (p->signal->tty == tty) {
2859 printk(KERN_NOTICE "SAK: killed process %d"
2860 " (%s): task_session(p)==tty->session\n",
2861 task_pid_nr(p), p->comm);
2862 send_sig(SIGKILL, p, 1);
2868 * We don't take a ref to the file, so we must
2869 * hold ->file_lock instead.
2871 spin_lock(&p->files->file_lock);
2872 fdt = files_fdtable(p->files);
2873 for (i = 0; i < fdt->max_fds; i++) {
2874 filp = fcheck_files(p->files, i);
2877 if (filp->f_op->read == tty_read &&
2878 file_tty(filp) == tty) {
2879 printk(KERN_NOTICE "SAK: killed process %d"
2880 " (%s): fd#%d opened to the tty\n",
2881 task_pid_nr(p), p->comm, i);
2882 force_sig(SIGKILL, p);
2886 spin_unlock(&p->files->file_lock);
2889 } while_each_thread(g, p);
2890 read_unlock(&tasklist_lock);
2894 static void do_SAK_work(struct work_struct *work)
2896 struct tty_struct *tty =
2897 container_of(work, struct tty_struct, SAK_work);
2902 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2903 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2904 * the values which we write to it will be identical to the values which it
2905 * already has. --akpm
2907 void do_SAK(struct tty_struct *tty)
2911 schedule_work(&tty->SAK_work);
2914 EXPORT_SYMBOL(do_SAK);
2916 static int dev_match_devt(struct device *dev, void *data)
2919 return dev->devt == *devt;
2922 /* Must put_device() after it's unused! */
2923 static struct device *tty_get_device(struct tty_struct *tty)
2925 dev_t devt = tty_devnum(tty);
2926 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2931 * initialize_tty_struct
2932 * @tty: tty to initialize
2934 * This subroutine initializes a tty structure that has been newly
2937 * Locking: none - tty in question must not be exposed at this point
2940 void initialize_tty_struct(struct tty_struct *tty,
2941 struct tty_driver *driver, int idx)
2943 memset(tty, 0, sizeof(struct tty_struct));
2944 kref_init(&tty->kref);
2945 tty->magic = TTY_MAGIC;
2946 tty_ldisc_init(tty);
2947 tty->session = NULL;
2949 tty->overrun_time = jiffies;
2950 tty->buf.head = tty->buf.tail = NULL;
2951 tty_buffer_init(tty);
2952 mutex_init(&tty->termios_mutex);
2953 mutex_init(&tty->ldisc_mutex);
2954 init_waitqueue_head(&tty->write_wait);
2955 init_waitqueue_head(&tty->read_wait);
2956 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2957 mutex_init(&tty->atomic_read_lock);
2958 mutex_init(&tty->atomic_write_lock);
2959 mutex_init(&tty->output_lock);
2960 mutex_init(&tty->echo_lock);
2961 spin_lock_init(&tty->read_lock);
2962 spin_lock_init(&tty->ctrl_lock);
2963 INIT_LIST_HEAD(&tty->tty_files);
2964 INIT_WORK(&tty->SAK_work, do_SAK_work);
2966 tty->driver = driver;
2967 tty->ops = driver->ops;
2969 tty_line_name(driver, idx, tty->name);
2970 tty->dev = tty_get_device(tty);
2974 * deinitialize_tty_struct
2975 * @tty: tty to deinitialize
2977 * This subroutine deinitializes a tty structure that has been newly
2978 * allocated but tty_release cannot be called on that yet.
2980 * Locking: none - tty in question must not be exposed at this point
2982 void deinitialize_tty_struct(struct tty_struct *tty)
2984 tty_ldisc_deinit(tty);
2988 * tty_put_char - write one character to a tty
2992 * Write one byte to the tty using the provided put_char method
2993 * if present. Returns the number of characters successfully output.
2995 * Note: the specific put_char operation in the driver layer may go
2996 * away soon. Don't call it directly, use this method
2999 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3001 if (tty->ops->put_char)
3002 return tty->ops->put_char(tty, ch);
3003 return tty->ops->write(tty, &ch, 1);
3005 EXPORT_SYMBOL_GPL(tty_put_char);
3007 struct class *tty_class;
3010 * tty_register_device - register a tty device
3011 * @driver: the tty driver that describes the tty device
3012 * @index: the index in the tty driver for this tty device
3013 * @device: a struct device that is associated with this tty device.
3014 * This field is optional, if there is no known struct device
3015 * for this tty device it can be set to NULL safely.
3017 * Returns a pointer to the struct device for this tty device
3018 * (or ERR_PTR(-EFOO) on error).
3020 * This call is required to be made to register an individual tty device
3021 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3022 * that bit is not set, this function should not be called by a tty
3028 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3029 struct device *device)
3032 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
3034 if (index >= driver->num) {
3035 printk(KERN_ERR "Attempt to register invalid tty line number "
3037 return ERR_PTR(-EINVAL);
3040 if (driver->type == TTY_DRIVER_TYPE_PTY)
3041 pty_line_name(driver, index, name);
3043 tty_line_name(driver, index, name);
3045 return device_create(tty_class, device, dev, NULL, name);
3047 EXPORT_SYMBOL(tty_register_device);
3050 * tty_unregister_device - unregister a tty device
3051 * @driver: the tty driver that describes the tty device
3052 * @index: the index in the tty driver for this tty device
3054 * If a tty device is registered with a call to tty_register_device() then
3055 * this function must be called when the tty device is gone.
3060 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3062 device_destroy(tty_class,
3063 MKDEV(driver->major, driver->minor_start) + index);
3065 EXPORT_SYMBOL(tty_unregister_device);
3067 struct tty_driver *alloc_tty_driver(int lines)
3069 struct tty_driver *driver;
3071 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3073 kref_init(&driver->kref);
3074 driver->magic = TTY_DRIVER_MAGIC;
3075 driver->num = lines;
3076 /* later we'll move allocation of tables here */
3080 EXPORT_SYMBOL(alloc_tty_driver);
3082 static void destruct_tty_driver(struct kref *kref)
3084 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3086 struct ktermios *tp;
3089 if (driver->flags & TTY_DRIVER_INSTALLED) {
3091 * Free the termios and termios_locked structures because
3092 * we don't want to get memory leaks when modular tty
3093 * drivers are removed from the kernel.
3095 for (i = 0; i < driver->num; i++) {
3096 tp = driver->termios[i];
3098 driver->termios[i] = NULL;
3101 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3102 tty_unregister_device(driver, i);
3105 proc_tty_unregister_driver(driver);
3106 driver->ttys = NULL;
3107 driver->termios = NULL;
3109 cdev_del(&driver->cdev);
3114 void tty_driver_kref_put(struct tty_driver *driver)
3116 kref_put(&driver->kref, destruct_tty_driver);
3118 EXPORT_SYMBOL(tty_driver_kref_put);
3120 void tty_set_operations(struct tty_driver *driver,
3121 const struct tty_operations *op)
3125 EXPORT_SYMBOL(tty_set_operations);
3127 void put_tty_driver(struct tty_driver *d)
3129 tty_driver_kref_put(d);
3131 EXPORT_SYMBOL(put_tty_driver);
3134 * Called by a tty driver to register itself.
3136 int tty_register_driver(struct tty_driver *driver)
3144 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3145 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3150 if (!driver->major) {
3151 error = alloc_chrdev_region(&dev, driver->minor_start,
3152 driver->num, driver->name);
3154 driver->major = MAJOR(dev);
3155 driver->minor_start = MINOR(dev);
3158 dev = MKDEV(driver->major, driver->minor_start);
3159 error = register_chrdev_region(dev, driver->num, driver->name);
3167 driver->ttys = (struct tty_struct **)p;
3168 driver->termios = (struct ktermios **)(p + driver->num);
3170 driver->ttys = NULL;
3171 driver->termios = NULL;
3174 cdev_init(&driver->cdev, &tty_fops);
3175 driver->cdev.owner = driver->owner;
3176 error = cdev_add(&driver->cdev, dev, driver->num);
3178 unregister_chrdev_region(dev, driver->num);
3179 driver->ttys = NULL;
3180 driver->termios = NULL;
3185 mutex_lock(&tty_mutex);
3186 list_add(&driver->tty_drivers, &tty_drivers);
3187 mutex_unlock(&tty_mutex);
3189 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3190 for (i = 0; i < driver->num; i++) {
3191 d = tty_register_device(driver, i, NULL);
3198 proc_tty_register_driver(driver);
3199 driver->flags |= TTY_DRIVER_INSTALLED;
3203 for (i--; i >= 0; i--)
3204 tty_unregister_device(driver, i);
3206 mutex_lock(&tty_mutex);
3207 list_del(&driver->tty_drivers);
3208 mutex_unlock(&tty_mutex);
3210 unregister_chrdev_region(dev, driver->num);
3211 driver->ttys = NULL;
3212 driver->termios = NULL;
3217 EXPORT_SYMBOL(tty_register_driver);
3220 * Called by a tty driver to unregister itself.
3222 int tty_unregister_driver(struct tty_driver *driver)
3226 if (driver->refcount)
3229 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3231 mutex_lock(&tty_mutex);
3232 list_del(&driver->tty_drivers);
3233 mutex_unlock(&tty_mutex);
3237 EXPORT_SYMBOL(tty_unregister_driver);
3239 dev_t tty_devnum(struct tty_struct *tty)
3241 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3243 EXPORT_SYMBOL(tty_devnum);
3245 void proc_clear_tty(struct task_struct *p)
3247 unsigned long flags;
3248 struct tty_struct *tty;
3249 spin_lock_irqsave(&p->sighand->siglock, flags);
3250 tty = p->signal->tty;
3251 p->signal->tty = NULL;
3252 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3256 /* Called under the sighand lock */
3258 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3261 unsigned long flags;
3262 /* We should not have a session or pgrp to put here but.... */
3263 spin_lock_irqsave(&tty->ctrl_lock, flags);
3264 put_pid(tty->session);
3266 tty->pgrp = get_pid(task_pgrp(tsk));
3267 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3268 tty->session = get_pid(task_session(tsk));
3269 if (tsk->signal->tty) {
3270 printk(KERN_DEBUG "tty not NULL!!\n");
3271 tty_kref_put(tsk->signal->tty);
3274 put_pid(tsk->signal->tty_old_pgrp);
3275 tsk->signal->tty = tty_kref_get(tty);
3276 tsk->signal->tty_old_pgrp = NULL;
3279 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3281 spin_lock_irq(&tsk->sighand->siglock);
3282 __proc_set_tty(tsk, tty);
3283 spin_unlock_irq(&tsk->sighand->siglock);
3286 struct tty_struct *get_current_tty(void)
3288 struct tty_struct *tty;
3289 unsigned long flags;
3291 spin_lock_irqsave(¤t->sighand->siglock, flags);
3292 tty = tty_kref_get(current->signal->tty);
3293 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3296 EXPORT_SYMBOL_GPL(get_current_tty);
3298 void tty_default_fops(struct file_operations *fops)
3304 * Initialize the console device. This is called *early*, so
3305 * we can't necessarily depend on lots of kernel help here.
3306 * Just do some early initializations, and do the complex setup
3309 void __init console_init(void)
3313 /* Setup the default TTY line discipline. */
3317 * set up the console device so that later boot sequences can
3318 * inform about problems etc..
3320 call = __con_initcall_start;
3321 while (call < __con_initcall_end) {
3327 static char *tty_devnode(struct device *dev, umode_t *mode)
3331 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3332 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3337 static int __init tty_class_init(void)
3339 tty_class = class_create(THIS_MODULE, "tty");
3340 if (IS_ERR(tty_class))
3341 return PTR_ERR(tty_class);
3342 tty_class->devnode = tty_devnode;
3346 postcore_initcall(tty_class_init);
3348 /* 3/2004 jmc: why do these devices exist? */
3349 static struct cdev tty_cdev, console_cdev;
3351 static ssize_t show_cons_active(struct device *dev,
3352 struct device_attribute *attr, char *buf)
3354 struct console *cs[16];
3360 for_each_console(c) {
3365 if ((c->flags & CON_ENABLED) == 0)
3368 if (i >= ARRAY_SIZE(cs))
3372 count += sprintf(buf + count, "%s%d%c",
3373 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3378 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3380 static struct device *consdev;
3382 void console_sysfs_notify(void)
3385 sysfs_notify(&consdev->kobj, NULL, "active");
3389 * Ok, now we can initialize the rest of the tty devices and can count
3390 * on memory allocations, interrupts etc..
3392 int __init tty_init(void)
3394 cdev_init(&tty_cdev, &tty_fops);
3395 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3396 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3397 panic("Couldn't register /dev/tty driver\n");
3398 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3400 cdev_init(&console_cdev, &console_fops);
3401 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3402 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3403 panic("Couldn't register /dev/console driver\n");
3404 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3406 if (IS_ERR(consdev))
3409 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3413 vty_init(&console_fops);