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>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
114 .c_iflag = ICRNL | IXON,
115 .c_oflag = OPOST | ONLCR,
116 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
117 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
118 ECHOCTL | ECHOKE | IEXTEN,
124 EXPORT_SYMBOL(tty_std_termios);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex);
135 EXPORT_SYMBOL(tty_mutex);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock);
140 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
141 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
142 ssize_t redirected_tty_write(struct file *, const char __user *,
144 static unsigned int tty_poll(struct file *, poll_table *);
145 static int tty_open(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd, struct file *filp, int on);
154 static int tty_fasync(int fd, struct file *filp, int on);
155 static void release_tty(struct tty_struct *tty, int idx);
156 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
157 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
160 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct *alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct *tty)
187 put_device(tty->dev);
188 kfree(tty->write_buf);
189 tty_buffer_free_all(tty);
190 tty->magic = 0xDEADDEAD;
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 /* FIXME: Review locking here. The tty_lock never covered any race
862 between a new association and proc_clear_tty but possible we need
863 to protect against this anyway */
864 struct task_struct *tsk = current;
865 disassociate_ctty(0);
871 * stop_tty - propagate flow control
874 * Perform flow control to the driver. For PTY/TTY pairs we
875 * must also propagate the TIOCKPKT status. May be called
876 * on an already stopped device and will not re-call the driver
879 * This functionality is used by both the line disciplines for
880 * halting incoming flow and by the driver. It may therefore be
881 * called from any context, may be under the tty atomic_write_lock
885 * Uses the tty control lock internally
888 void stop_tty(struct tty_struct *tty)
891 spin_lock_irqsave(&tty->ctrl_lock, flags);
893 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
897 if (tty->link && tty->link->packet) {
898 tty->ctrl_status &= ~TIOCPKT_START;
899 tty->ctrl_status |= TIOCPKT_STOP;
900 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
902 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
904 (tty->ops->stop)(tty);
907 EXPORT_SYMBOL(stop_tty);
910 * start_tty - propagate flow control
913 * Start a tty that has been stopped if at all possible. Perform
914 * any necessary wakeups and propagate the TIOCPKT status. If this
915 * is the tty was previous stopped and is being started then the
916 * driver start method is invoked and the line discipline woken.
922 void start_tty(struct tty_struct *tty)
925 spin_lock_irqsave(&tty->ctrl_lock, flags);
926 if (!tty->stopped || tty->flow_stopped) {
927 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
931 if (tty->link && tty->link->packet) {
932 tty->ctrl_status &= ~TIOCPKT_STOP;
933 tty->ctrl_status |= TIOCPKT_START;
934 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
936 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
938 (tty->ops->start)(tty);
939 /* If we have a running line discipline it may need kicking */
943 EXPORT_SYMBOL(start_tty);
946 * tty_read - read method for tty device files
947 * @file: pointer to tty file
949 * @count: size of user buffer
952 * Perform the read system call function on this terminal device. Checks
953 * for hung up devices before calling the line discipline method.
956 * Locks the line discipline internally while needed. Multiple
957 * read calls may be outstanding in parallel.
960 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
964 struct inode *inode = file->f_path.dentry->d_inode;
965 struct tty_struct *tty = file_tty(file);
966 struct tty_ldisc *ld;
968 if (tty_paranoia_check(tty, inode, "tty_read"))
970 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
973 /* We want to wait for the line discipline to sort out in this
975 ld = tty_ldisc_ref_wait(tty);
977 i = (ld->ops->read)(tty, file, buf, count);
982 inode->i_atime = current_fs_time(inode->i_sb);
986 void tty_write_unlock(struct tty_struct *tty)
987 __releases(&tty->atomic_write_lock)
989 mutex_unlock(&tty->atomic_write_lock);
990 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
993 int tty_write_lock(struct tty_struct *tty, int ndelay)
994 __acquires(&tty->atomic_write_lock)
996 if (!mutex_trylock(&tty->atomic_write_lock)) {
999 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1000 return -ERESTARTSYS;
1006 * Split writes up in sane blocksizes to avoid
1007 * denial-of-service type attacks
1009 static inline ssize_t do_tty_write(
1010 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1011 struct tty_struct *tty,
1013 const char __user *buf,
1016 ssize_t ret, written = 0;
1019 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1024 * We chunk up writes into a temporary buffer. This
1025 * simplifies low-level drivers immensely, since they
1026 * don't have locking issues and user mode accesses.
1028 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1031 * The default chunk-size is 2kB, because the NTTY
1032 * layer has problems with bigger chunks. It will
1033 * claim to be able to handle more characters than
1036 * FIXME: This can probably go away now except that 64K chunks
1037 * are too likely to fail unless switched to vmalloc...
1040 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1045 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1046 if (tty->write_cnt < chunk) {
1047 unsigned char *buf_chunk;
1052 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1057 kfree(tty->write_buf);
1058 tty->write_cnt = chunk;
1059 tty->write_buf = buf_chunk;
1062 /* Do the write .. */
1064 size_t size = count;
1068 if (copy_from_user(tty->write_buf, buf, size))
1070 ret = write(tty, file, tty->write_buf, size);
1079 if (signal_pending(current))
1084 struct inode *inode = file->f_path.dentry->d_inode;
1085 inode->i_mtime = current_fs_time(inode->i_sb);
1089 tty_write_unlock(tty);
1094 * tty_write_message - write a message to a certain tty, not just the console.
1095 * @tty: the destination tty_struct
1096 * @msg: the message to write
1098 * This is used for messages that need to be redirected to a specific tty.
1099 * We don't put it into the syslog queue right now maybe in the future if
1102 * We must still hold the BTM and test the CLOSING flag for the moment.
1105 void tty_write_message(struct tty_struct *tty, char *msg)
1108 mutex_lock(&tty->atomic_write_lock);
1110 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1112 tty->ops->write(tty, msg, strlen(msg));
1115 tty_write_unlock(tty);
1122 * tty_write - write method for tty device file
1123 * @file: tty file pointer
1124 * @buf: user data to write
1125 * @count: bytes to write
1128 * Write data to a tty device via the line discipline.
1131 * Locks the line discipline as required
1132 * Writes to the tty driver are serialized by the atomic_write_lock
1133 * and are then processed in chunks to the device. The line discipline
1134 * write method will not be invoked in parallel for each device.
1137 static ssize_t tty_write(struct file *file, const char __user *buf,
1138 size_t count, loff_t *ppos)
1140 struct inode *inode = file->f_path.dentry->d_inode;
1141 struct tty_struct *tty = file_tty(file);
1142 struct tty_ldisc *ld;
1145 if (tty_paranoia_check(tty, inode, "tty_write"))
1147 if (!tty || !tty->ops->write ||
1148 (test_bit(TTY_IO_ERROR, &tty->flags)))
1150 /* Short term debug to catch buggy drivers */
1151 if (tty->ops->write_room == NULL)
1152 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1154 ld = tty_ldisc_ref_wait(tty);
1155 if (!ld->ops->write)
1158 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1159 tty_ldisc_deref(ld);
1163 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1164 size_t count, loff_t *ppos)
1166 struct file *p = NULL;
1168 spin_lock(&redirect_lock);
1173 spin_unlock(&redirect_lock);
1177 res = vfs_write(p, buf, count, &p->f_pos);
1181 return tty_write(file, buf, count, ppos);
1184 static char ptychar[] = "pqrstuvwxyzabcde";
1187 * pty_line_name - generate name for a pty
1188 * @driver: the tty driver in use
1189 * @index: the minor number
1190 * @p: output buffer of at least 6 bytes
1192 * Generate a name from a driver reference and write it to the output
1197 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1199 int i = index + driver->name_base;
1200 /* ->name is initialized to "ttyp", but "tty" is expected */
1201 sprintf(p, "%s%c%x",
1202 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1203 ptychar[i >> 4 & 0xf], i & 0xf);
1207 * tty_line_name - generate name for a tty
1208 * @driver: the tty driver in use
1209 * @index: the minor number
1210 * @p: output buffer of at least 7 bytes
1212 * Generate a name from a driver reference and write it to the output
1217 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1219 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1220 strcpy(p, driver->name);
1222 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1226 * tty_driver_lookup_tty() - find an existing tty, if any
1227 * @driver: the driver for the tty
1228 * @idx: the minor number
1230 * Return the tty, if found or ERR_PTR() otherwise.
1232 * Locking: tty_mutex must be held. If tty is found, the mutex must
1233 * be held until the 'fast-open' is also done. Will change once we
1234 * have refcounting in the driver and per driver locking
1236 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1237 struct inode *inode, int idx)
1239 if (driver->ops->lookup)
1240 return driver->ops->lookup(driver, inode, idx);
1242 return driver->ttys[idx];
1246 * tty_init_termios - helper for termios setup
1247 * @tty: the tty to set up
1249 * Initialise the termios structures for this tty. Thus runs under
1250 * the tty_mutex currently so we can be relaxed about ordering.
1253 int tty_init_termios(struct tty_struct *tty)
1255 struct ktermios *tp;
1256 int idx = tty->index;
1258 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1259 tty->termios = tty->driver->init_termios;
1261 /* Check for lazy saved data */
1262 tp = tty->driver->termios[idx];
1266 tty->termios = tty->driver->init_termios;
1268 /* Compatibility until drivers always set this */
1269 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1270 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1273 EXPORT_SYMBOL_GPL(tty_init_termios);
1275 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1277 int ret = tty_init_termios(tty);
1281 tty_driver_kref_get(driver);
1283 driver->ttys[tty->index] = tty;
1286 EXPORT_SYMBOL_GPL(tty_standard_install);
1289 * tty_driver_install_tty() - install a tty entry in the driver
1290 * @driver: the driver for the tty
1293 * Install a tty object into the driver tables. The tty->index field
1294 * will be set by the time this is called. This method is responsible
1295 * for ensuring any need additional structures are allocated and
1298 * Locking: tty_mutex for now
1300 static int tty_driver_install_tty(struct tty_driver *driver,
1301 struct tty_struct *tty)
1303 return driver->ops->install ? driver->ops->install(driver, tty) :
1304 tty_standard_install(driver, tty);
1308 * tty_driver_remove_tty() - remove a tty from the driver tables
1309 * @driver: the driver for the tty
1310 * @idx: the minor number
1312 * Remvoe a tty object from the driver tables. The tty->index field
1313 * will be set by the time this is called.
1315 * Locking: tty_mutex for now
1317 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1319 if (driver->ops->remove)
1320 driver->ops->remove(driver, tty);
1322 driver->ttys[tty->index] = NULL;
1326 * tty_reopen() - fast re-open of an open tty
1327 * @tty - the tty to open
1329 * Return 0 on success, -errno on error.
1331 * Locking: tty_mutex must be held from the time the tty was found
1332 * till this open completes.
1334 static int tty_reopen(struct tty_struct *tty)
1336 struct tty_driver *driver = tty->driver;
1338 if (test_bit(TTY_CLOSING, &tty->flags) ||
1339 test_bit(TTY_HUPPING, &tty->flags) ||
1340 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1343 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1344 driver->subtype == PTY_TYPE_MASTER) {
1346 * special case for PTY masters: only one open permitted,
1347 * and the slave side open count is incremented as well.
1356 mutex_lock(&tty->ldisc_mutex);
1357 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1358 mutex_unlock(&tty->ldisc_mutex);
1364 * tty_init_dev - initialise a tty device
1365 * @driver: tty driver we are opening a device on
1366 * @idx: device index
1367 * @ret_tty: returned tty structure
1369 * Prepare a tty device. This may not be a "new" clean device but
1370 * could also be an active device. The pty drivers require special
1371 * handling because of this.
1374 * The function is called under the tty_mutex, which
1375 * protects us from the tty struct or driver itself going away.
1377 * On exit the tty device has the line discipline attached and
1378 * a reference count of 1. If a pair was created for pty/tty use
1379 * and the other was a pty master then it too has a reference count of 1.
1381 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1382 * failed open. The new code protects the open with a mutex, so it's
1383 * really quite straightforward. The mutex locking can probably be
1384 * relaxed for the (most common) case of reopening a tty.
1387 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1389 struct tty_struct *tty;
1393 * First time open is complex, especially for PTY devices.
1394 * This code guarantees that either everything succeeds and the
1395 * TTY is ready for operation, or else the table slots are vacated
1396 * and the allocated memory released. (Except that the termios
1397 * and locked termios may be retained.)
1400 if (!try_module_get(driver->owner))
1401 return ERR_PTR(-ENODEV);
1403 tty = alloc_tty_struct();
1406 goto err_module_put;
1408 initialize_tty_struct(tty, driver, idx);
1411 retval = tty_driver_install_tty(driver, tty);
1413 goto err_deinit_tty;
1416 tty->port = driver->ports[idx];
1418 WARN_RATELIMIT(!tty->port,
1419 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1420 __func__, tty->driver->name);
1423 * Structures all installed ... call the ldisc open routines.
1424 * If we fail here just call release_tty to clean up. No need
1425 * to decrement the use counts, as release_tty doesn't care.
1427 retval = tty_ldisc_setup(tty, tty->link);
1429 goto err_release_tty;
1430 /* Return the tty locked so that it cannot vanish under the caller */
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 */
1444 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1445 "clearing slot %d\n", idx);
1446 release_tty(tty, idx);
1447 return ERR_PTR(retval);
1450 void tty_free_termios(struct tty_struct *tty)
1452 struct ktermios *tp;
1453 int idx = tty->index;
1455 /* If the port is going to reset then it has no termios to save */
1456 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1459 /* Stash the termios data */
1460 tp = tty->driver->termios[idx];
1462 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1464 pr_warn("tty: no memory to save termios state.\n");
1467 tty->driver->termios[idx] = tp;
1471 EXPORT_SYMBOL(tty_free_termios);
1475 * release_one_tty - release tty structure memory
1476 * @kref: kref of tty we are obliterating
1478 * Releases memory associated with a tty structure, and clears out the
1479 * driver table slots. This function is called when a device is no longer
1480 * in use. It also gets called when setup of a device fails.
1483 * takes the file list lock internally when working on the list
1484 * of ttys that the driver keeps.
1486 * This method gets called from a work queue so that the driver private
1487 * cleanup ops can sleep (needed for USB at least)
1489 static void release_one_tty(struct work_struct *work)
1491 struct tty_struct *tty =
1492 container_of(work, struct tty_struct, hangup_work);
1493 struct tty_driver *driver = tty->driver;
1495 if (tty->ops->cleanup)
1496 tty->ops->cleanup(tty);
1499 tty_driver_kref_put(driver);
1500 module_put(driver->owner);
1502 spin_lock(&tty_files_lock);
1503 list_del_init(&tty->tty_files);
1504 spin_unlock(&tty_files_lock);
1507 put_pid(tty->session);
1508 free_tty_struct(tty);
1511 static void queue_release_one_tty(struct kref *kref)
1513 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1515 /* The hangup queue is now free so we can reuse it rather than
1516 waste a chunk of memory for each port */
1517 INIT_WORK(&tty->hangup_work, release_one_tty);
1518 schedule_work(&tty->hangup_work);
1522 * tty_kref_put - release a tty kref
1525 * Release a reference to a tty device and if need be let the kref
1526 * layer destruct the object for us
1529 void tty_kref_put(struct tty_struct *tty)
1532 kref_put(&tty->kref, queue_release_one_tty);
1534 EXPORT_SYMBOL(tty_kref_put);
1537 * release_tty - release tty structure memory
1539 * Release both @tty and a possible linked partner (think pty pair),
1540 * and decrement the refcount of the backing module.
1544 * takes the file list lock internally when working on the list
1545 * of ttys that the driver keeps.
1548 static void release_tty(struct tty_struct *tty, int idx)
1550 /* This should always be true but check for the moment */
1551 WARN_ON(tty->index != idx);
1552 WARN_ON(!mutex_is_locked(&tty_mutex));
1553 if (tty->ops->shutdown)
1554 tty->ops->shutdown(tty);
1555 tty_free_termios(tty);
1556 tty_driver_remove_tty(tty->driver, tty);
1559 tty_kref_put(tty->link);
1564 * tty_release_checks - check a tty before real release
1565 * @tty: tty to check
1566 * @o_tty: link of @tty (if any)
1567 * @idx: index of the tty
1569 * Performs some paranoid checking before true release of the @tty.
1570 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1572 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1575 #ifdef TTY_PARANOIA_CHECK
1576 if (idx < 0 || idx >= tty->driver->num) {
1577 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1578 __func__, tty->name);
1582 /* not much to check for devpts */
1583 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1586 if (tty != tty->driver->ttys[idx]) {
1587 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1588 __func__, idx, tty->name);
1591 if (tty->driver->other) {
1592 if (o_tty != tty->driver->other->ttys[idx]) {
1593 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1594 __func__, idx, tty->name);
1597 if (o_tty->link != tty) {
1598 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1607 * tty_release - vfs callback for close
1608 * @inode: inode of tty
1609 * @filp: file pointer for handle to tty
1611 * Called the last time each file handle is closed that references
1612 * this tty. There may however be several such references.
1615 * Takes bkl. See tty_release_dev
1617 * Even releasing the tty structures is a tricky business.. We have
1618 * to be very careful that the structures are all released at the
1619 * same time, as interrupts might otherwise get the wrong pointers.
1621 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1622 * lead to double frees or releasing memory still in use.
1625 int tty_release(struct inode *inode, struct file *filp)
1627 struct tty_struct *tty = file_tty(filp);
1628 struct tty_struct *o_tty;
1629 int pty_master, tty_closing, o_tty_closing, do_sleep;
1634 if (tty_paranoia_check(tty, inode, __func__))
1638 check_tty_count(tty, __func__);
1640 __tty_fasync(-1, filp, 0);
1643 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1644 tty->driver->subtype == PTY_TYPE_MASTER);
1645 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1646 /* Review: parallel close */
1649 if (tty_release_checks(tty, o_tty, idx)) {
1654 #ifdef TTY_DEBUG_HANGUP
1655 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1656 tty_name(tty, buf), tty->count);
1659 if (tty->ops->close)
1660 tty->ops->close(tty, filp);
1664 * Sanity check: if tty->count is going to zero, there shouldn't be
1665 * any waiters on tty->read_wait or tty->write_wait. We test the
1666 * wait queues and kick everyone out _before_ actually starting to
1667 * close. This ensures that we won't block while releasing the tty
1670 * The test for the o_tty closing is necessary, since the master and
1671 * slave sides may close in any order. If the slave side closes out
1672 * first, its count will be one, since the master side holds an open.
1673 * Thus this test wouldn't be triggered at the time the slave closes,
1676 * Note that it's possible for the tty to be opened again while we're
1677 * flushing out waiters. By recalculating the closing flags before
1678 * each iteration we avoid any problems.
1681 /* Guard against races with tty->count changes elsewhere and
1682 opens on /dev/tty */
1684 mutex_lock(&tty_mutex);
1685 tty_lock_pair(tty, o_tty);
1686 tty_closing = tty->count <= 1;
1687 o_tty_closing = o_tty &&
1688 (o_tty->count <= (pty_master ? 1 : 0));
1692 if (waitqueue_active(&tty->read_wait)) {
1693 wake_up_poll(&tty->read_wait, POLLIN);
1696 if (waitqueue_active(&tty->write_wait)) {
1697 wake_up_poll(&tty->write_wait, POLLOUT);
1701 if (o_tty_closing) {
1702 if (waitqueue_active(&o_tty->read_wait)) {
1703 wake_up_poll(&o_tty->read_wait, POLLIN);
1706 if (waitqueue_active(&o_tty->write_wait)) {
1707 wake_up_poll(&o_tty->write_wait, POLLOUT);
1714 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1715 __func__, tty_name(tty, buf));
1716 tty_unlock_pair(tty, o_tty);
1717 mutex_unlock(&tty_mutex);
1722 * The closing flags are now consistent with the open counts on
1723 * both sides, and we've completed the last operation that could
1724 * block, so it's safe to proceed with closing.
1726 * We must *not* drop the tty_mutex until we ensure that a further
1727 * entry into tty_open can not pick up this tty.
1730 if (--o_tty->count < 0) {
1731 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1732 __func__, o_tty->count, tty_name(o_tty, buf));
1736 if (--tty->count < 0) {
1737 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1738 __func__, tty->count, tty_name(tty, buf));
1743 * We've decremented tty->count, so we need to remove this file
1744 * descriptor off the tty->tty_files list; this serves two
1746 * - check_tty_count sees the correct number of file descriptors
1747 * associated with this tty.
1748 * - do_tty_hangup no longer sees this file descriptor as
1749 * something that needs to be handled for hangups.
1754 * Perform some housekeeping before deciding whether to return.
1756 * Set the TTY_CLOSING flag if this was the last open. In the
1757 * case of a pty we may have to wait around for the other side
1758 * to close, and TTY_CLOSING makes sure we can't be reopened.
1761 set_bit(TTY_CLOSING, &tty->flags);
1763 set_bit(TTY_CLOSING, &o_tty->flags);
1766 * If _either_ side is closing, make sure there aren't any
1767 * processes that still think tty or o_tty is their controlling
1770 if (tty_closing || o_tty_closing) {
1771 read_lock(&tasklist_lock);
1772 session_clear_tty(tty->session);
1774 session_clear_tty(o_tty->session);
1775 read_unlock(&tasklist_lock);
1778 mutex_unlock(&tty_mutex);
1779 tty_unlock_pair(tty, o_tty);
1780 /* At this point the TTY_CLOSING flag should ensure a dead tty
1781 cannot be re-opened by a racing opener */
1783 /* check whether both sides are closing ... */
1784 if (!tty_closing || (o_tty && !o_tty_closing))
1787 #ifdef TTY_DEBUG_HANGUP
1788 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1791 * Ask the line discipline code to release its structures
1793 tty_ldisc_release(tty, o_tty);
1795 * The release_tty function takes care of the details of clearing
1796 * the slots and preserving the termios structure. The tty_unlock_pair
1797 * should be safe as we keep a kref while the tty is locked (so the
1798 * unlock never unlocks a freed tty).
1800 mutex_lock(&tty_mutex);
1801 release_tty(tty, idx);
1802 mutex_unlock(&tty_mutex);
1804 /* Make this pty number available for reallocation */
1806 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 * We need to move to returning a refcounted object from all the lookup
1820 * paths including this one.
1822 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1824 struct tty_struct *tty;
1826 if (device != MKDEV(TTYAUX_MAJOR, 0))
1829 tty = get_current_tty();
1831 return ERR_PTR(-ENXIO);
1833 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1836 /* FIXME: we put a reference and return a TTY! */
1837 /* This is only safe because the caller holds tty_mutex */
1842 * tty_lookup_driver - lookup a tty driver for a given device file
1843 * @device: device number
1844 * @filp: file pointer to tty
1845 * @noctty: set if the device should not become a controlling tty
1846 * @index: index for the device in the @return driver
1847 * @return: driver for this inode (with increased refcount)
1849 * If @return is not erroneous, the caller is responsible to decrement the
1850 * refcount by tty_driver_kref_put.
1852 * Locking: tty_mutex protects get_tty_driver
1854 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1855 int *noctty, int *index)
1857 struct tty_driver *driver;
1861 case MKDEV(TTY_MAJOR, 0): {
1862 extern struct tty_driver *console_driver;
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
1911 * Note: the tty_unlock/lock cases without a ref are only safe due to
1915 static int tty_open(struct inode *inode, struct file *filp)
1917 struct tty_struct *tty;
1919 struct tty_driver *driver = NULL;
1921 dev_t device = inode->i_rdev;
1922 unsigned saved_flags = filp->f_flags;
1924 nonseekable_open(inode, filp);
1927 retval = tty_alloc_file(filp);
1931 noctty = filp->f_flags & O_NOCTTY;
1935 mutex_lock(&tty_mutex);
1936 /* This is protected by the tty_mutex */
1937 tty = tty_open_current_tty(device, filp);
1939 retval = PTR_ERR(tty);
1942 driver = tty_lookup_driver(device, filp, &noctty, &index);
1943 if (IS_ERR(driver)) {
1944 retval = PTR_ERR(driver);
1948 /* check whether we're reopening an existing tty */
1949 tty = tty_driver_lookup_tty(driver, inode, index);
1951 retval = PTR_ERR(tty);
1958 retval = tty_reopen(tty);
1961 tty = ERR_PTR(retval);
1963 } else /* Returns with the tty_lock held for now */
1964 tty = tty_init_dev(driver, index);
1966 mutex_unlock(&tty_mutex);
1968 tty_driver_kref_put(driver);
1970 retval = PTR_ERR(tty);
1974 tty_add_file(tty, filp);
1976 check_tty_count(tty, __func__);
1977 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1978 tty->driver->subtype == PTY_TYPE_MASTER)
1980 #ifdef TTY_DEBUG_HANGUP
1981 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1984 retval = tty->ops->open(tty, filp);
1987 filp->f_flags = saved_flags;
1989 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1990 !capable(CAP_SYS_ADMIN))
1994 #ifdef TTY_DEBUG_HANGUP
1995 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
1998 tty_unlock(tty); /* need to call tty_release without BTM */
1999 tty_release(inode, filp);
2000 if (retval != -ERESTARTSYS)
2003 if (signal_pending(current))
2008 * Need to reset f_op in case a hangup happened.
2010 if (filp->f_op == &hung_up_tty_fops)
2011 filp->f_op = &tty_fops;
2017 mutex_lock(&tty_mutex);
2019 spin_lock_irq(¤t->sighand->siglock);
2021 current->signal->leader &&
2022 !current->signal->tty &&
2023 tty->session == NULL)
2024 __proc_set_tty(current, tty);
2025 spin_unlock_irq(¤t->sighand->siglock);
2027 mutex_unlock(&tty_mutex);
2030 mutex_unlock(&tty_mutex);
2031 /* after locks to avoid deadlock */
2032 if (!IS_ERR_OR_NULL(driver))
2033 tty_driver_kref_put(driver);
2035 tty_free_file(filp);
2042 * tty_poll - check tty status
2043 * @filp: file being polled
2044 * @wait: poll wait structures to update
2046 * Call the line discipline polling method to obtain the poll
2047 * status of the device.
2049 * Locking: locks called line discipline but ldisc poll method
2050 * may be re-entered freely by other callers.
2053 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2055 struct tty_struct *tty = file_tty(filp);
2056 struct tty_ldisc *ld;
2059 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2062 ld = tty_ldisc_ref_wait(tty);
2064 ret = (ld->ops->poll)(tty, filp, wait);
2065 tty_ldisc_deref(ld);
2069 static int __tty_fasync(int fd, struct file *filp, int on)
2071 struct tty_struct *tty = file_tty(filp);
2072 unsigned long flags;
2075 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2078 retval = fasync_helper(fd, filp, on, &tty->fasync);
2085 if (!waitqueue_active(&tty->read_wait))
2086 tty->minimum_to_wake = 1;
2087 spin_lock_irqsave(&tty->ctrl_lock, flags);
2090 type = PIDTYPE_PGID;
2092 pid = task_pid(current);
2096 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2097 retval = __f_setown(filp, pid, type, 0);
2102 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2103 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2110 static int tty_fasync(int fd, struct file *filp, int on)
2112 struct tty_struct *tty = file_tty(filp);
2116 retval = __tty_fasync(fd, filp, on);
2123 * tiocsti - fake input character
2124 * @tty: tty to fake input into
2125 * @p: pointer to character
2127 * Fake input to a tty device. Does the necessary locking and
2130 * FIXME: does not honour flow control ??
2133 * Called functions take tty_ldisc_lock
2134 * current->signal->tty check is safe without locks
2136 * FIXME: may race normal receive processing
2139 static int tiocsti(struct tty_struct *tty, char __user *p)
2142 struct tty_ldisc *ld;
2144 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2146 if (get_user(ch, p))
2148 tty_audit_tiocsti(tty, ch);
2149 ld = tty_ldisc_ref_wait(tty);
2150 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2151 tty_ldisc_deref(ld);
2156 * tiocgwinsz - implement window query ioctl
2158 * @arg: user buffer for result
2160 * Copies the kernel idea of the window size into the user buffer.
2162 * Locking: tty->termios_mutex is taken to ensure the winsize data
2166 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2170 mutex_lock(&tty->termios_mutex);
2171 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2172 mutex_unlock(&tty->termios_mutex);
2174 return err ? -EFAULT: 0;
2178 * tty_do_resize - resize event
2179 * @tty: tty being resized
2180 * @rows: rows (character)
2181 * @cols: cols (character)
2183 * Update the termios variables and send the necessary signals to
2184 * peform a terminal resize correctly
2187 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2190 unsigned long flags;
2193 mutex_lock(&tty->termios_mutex);
2194 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2196 /* Get the PID values and reference them so we can
2197 avoid holding the tty ctrl lock while sending signals */
2198 spin_lock_irqsave(&tty->ctrl_lock, flags);
2199 pgrp = get_pid(tty->pgrp);
2200 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2203 kill_pgrp(pgrp, SIGWINCH, 1);
2208 mutex_unlock(&tty->termios_mutex);
2213 * tiocswinsz - implement window size set ioctl
2214 * @tty; tty side of tty
2215 * @arg: user buffer for result
2217 * Copies the user idea of the window size to the kernel. Traditionally
2218 * this is just advisory information but for the Linux console it
2219 * actually has driver level meaning and triggers a VC resize.
2222 * Driver dependent. The default do_resize method takes the
2223 * tty termios mutex and ctrl_lock. The console takes its own lock
2224 * then calls into the default method.
2227 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2229 struct winsize tmp_ws;
2230 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2233 if (tty->ops->resize)
2234 return tty->ops->resize(tty, &tmp_ws);
2236 return tty_do_resize(tty, &tmp_ws);
2240 * tioccons - allow admin to move logical console
2241 * @file: the file to become console
2243 * Allow the administrator to move the redirected console device
2245 * Locking: uses redirect_lock to guard the redirect information
2248 static int tioccons(struct file *file)
2250 if (!capable(CAP_SYS_ADMIN))
2252 if (file->f_op->write == redirected_tty_write) {
2254 spin_lock(&redirect_lock);
2257 spin_unlock(&redirect_lock);
2262 spin_lock(&redirect_lock);
2264 spin_unlock(&redirect_lock);
2269 spin_unlock(&redirect_lock);
2274 * fionbio - non blocking ioctl
2275 * @file: file to set blocking value
2276 * @p: user parameter
2278 * Historical tty interfaces had a blocking control ioctl before
2279 * the generic functionality existed. This piece of history is preserved
2280 * in the expected tty API of posix OS's.
2282 * Locking: none, the open file handle ensures it won't go away.
2285 static int fionbio(struct file *file, int __user *p)
2289 if (get_user(nonblock, p))
2292 spin_lock(&file->f_lock);
2294 file->f_flags |= O_NONBLOCK;
2296 file->f_flags &= ~O_NONBLOCK;
2297 spin_unlock(&file->f_lock);
2302 * tiocsctty - set controlling tty
2303 * @tty: tty structure
2304 * @arg: user argument
2306 * This ioctl is used to manage job control. It permits a session
2307 * leader to set this tty as the controlling tty for the session.
2310 * Takes tty_mutex() to protect tty instance
2311 * Takes tasklist_lock internally to walk sessions
2312 * Takes ->siglock() when updating signal->tty
2315 static int tiocsctty(struct tty_struct *tty, int arg)
2318 if (current->signal->leader && (task_session(current) == tty->session))
2321 mutex_lock(&tty_mutex);
2323 * The process must be a session leader and
2324 * not have a controlling tty already.
2326 if (!current->signal->leader || current->signal->tty) {
2333 * This tty is already the controlling
2334 * tty for another session group!
2336 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2340 read_lock(&tasklist_lock);
2341 session_clear_tty(tty->session);
2342 read_unlock(&tasklist_lock);
2348 proc_set_tty(current, tty);
2350 mutex_unlock(&tty_mutex);
2355 * tty_get_pgrp - return a ref counted pgrp pid
2358 * Returns a refcounted instance of the pid struct for the process
2359 * group controlling the tty.
2362 struct pid *tty_get_pgrp(struct tty_struct *tty)
2364 unsigned long flags;
2367 spin_lock_irqsave(&tty->ctrl_lock, flags);
2368 pgrp = get_pid(tty->pgrp);
2369 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2373 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2376 * tiocgpgrp - get process group
2377 * @tty: tty passed by user
2378 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2381 * Obtain the process group of the tty. If there is no process group
2384 * Locking: none. Reference to current->signal->tty is safe.
2387 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2392 * (tty == real_tty) is a cheap way of
2393 * testing if the tty is NOT a master pty.
2395 if (tty == real_tty && current->signal->tty != real_tty)
2397 pid = tty_get_pgrp(real_tty);
2398 ret = put_user(pid_vnr(pid), p);
2404 * tiocspgrp - attempt to set process group
2405 * @tty: tty passed by user
2406 * @real_tty: tty side device matching tty passed by user
2409 * Set the process group of the tty to the session passed. Only
2410 * permitted where the tty session is our session.
2412 * Locking: RCU, ctrl lock
2415 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2419 int retval = tty_check_change(real_tty);
2420 unsigned long flags;
2426 if (!current->signal->tty ||
2427 (current->signal->tty != real_tty) ||
2428 (real_tty->session != task_session(current)))
2430 if (get_user(pgrp_nr, p))
2435 pgrp = find_vpid(pgrp_nr);
2440 if (session_of_pgrp(pgrp) != task_session(current))
2443 spin_lock_irqsave(&tty->ctrl_lock, flags);
2444 put_pid(real_tty->pgrp);
2445 real_tty->pgrp = get_pid(pgrp);
2446 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2453 * tiocgsid - get session id
2454 * @tty: tty passed by user
2455 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2456 * @p: pointer to returned session id
2458 * Obtain the session id of the tty. If there is no session
2461 * Locking: none. Reference to current->signal->tty is safe.
2464 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2467 * (tty == real_tty) is a cheap way of
2468 * testing if the tty is NOT a master pty.
2470 if (tty == real_tty && current->signal->tty != real_tty)
2472 if (!real_tty->session)
2474 return put_user(pid_vnr(real_tty->session), p);
2478 * tiocsetd - set line discipline
2480 * @p: pointer to user data
2482 * Set the line discipline according to user request.
2484 * Locking: see tty_set_ldisc, this function is just a helper
2487 static int tiocsetd(struct tty_struct *tty, int __user *p)
2492 if (get_user(ldisc, p))
2495 ret = tty_set_ldisc(tty, ldisc);
2501 * send_break - performed time break
2502 * @tty: device to break on
2503 * @duration: timeout in mS
2505 * Perform a timed break on hardware that lacks its own driver level
2506 * timed break functionality.
2509 * atomic_write_lock serializes
2513 static int send_break(struct tty_struct *tty, unsigned int duration)
2517 if (tty->ops->break_ctl == NULL)
2520 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2521 retval = tty->ops->break_ctl(tty, duration);
2523 /* Do the work ourselves */
2524 if (tty_write_lock(tty, 0) < 0)
2526 retval = tty->ops->break_ctl(tty, -1);
2529 if (!signal_pending(current))
2530 msleep_interruptible(duration);
2531 retval = tty->ops->break_ctl(tty, 0);
2533 tty_write_unlock(tty);
2534 if (signal_pending(current))
2541 * tty_tiocmget - get modem status
2543 * @file: user file pointer
2544 * @p: pointer to result
2546 * Obtain the modem status bits from the tty driver if the feature
2547 * is supported. Return -EINVAL if it is not available.
2549 * Locking: none (up to the driver)
2552 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2554 int retval = -EINVAL;
2556 if (tty->ops->tiocmget) {
2557 retval = tty->ops->tiocmget(tty);
2560 retval = put_user(retval, p);
2566 * tty_tiocmset - set modem status
2568 * @cmd: command - clear bits, set bits or set all
2569 * @p: pointer to desired bits
2571 * Set the modem status bits from the tty driver if the feature
2572 * is supported. Return -EINVAL if it is not available.
2574 * Locking: none (up to the driver)
2577 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2581 unsigned int set, clear, val;
2583 if (tty->ops->tiocmset == NULL)
2586 retval = get_user(val, p);
2602 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2603 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2604 return tty->ops->tiocmset(tty, set, clear);
2607 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2609 int retval = -EINVAL;
2610 struct serial_icounter_struct icount;
2611 memset(&icount, 0, sizeof(icount));
2612 if (tty->ops->get_icount)
2613 retval = tty->ops->get_icount(tty, &icount);
2616 if (copy_to_user(arg, &icount, sizeof(icount)))
2621 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2623 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2624 tty->driver->subtype == PTY_TYPE_MASTER)
2628 EXPORT_SYMBOL(tty_pair_get_tty);
2630 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2632 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2633 tty->driver->subtype == PTY_TYPE_MASTER)
2637 EXPORT_SYMBOL(tty_pair_get_pty);
2640 * Split this up, as gcc can choke on it otherwise..
2642 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2644 struct tty_struct *tty = file_tty(file);
2645 struct tty_struct *real_tty;
2646 void __user *p = (void __user *)arg;
2648 struct tty_ldisc *ld;
2649 struct inode *inode = file->f_dentry->d_inode;
2651 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2654 real_tty = tty_pair_get_tty(tty);
2657 * Factor out some common prep work
2665 retval = tty_check_change(tty);
2668 if (cmd != TIOCCBRK) {
2669 tty_wait_until_sent(tty, 0);
2670 if (signal_pending(current))
2681 return tiocsti(tty, p);
2683 return tiocgwinsz(real_tty, p);
2685 return tiocswinsz(real_tty, p);
2687 return real_tty != tty ? -EINVAL : tioccons(file);
2689 return fionbio(file, p);
2691 set_bit(TTY_EXCLUSIVE, &tty->flags);
2694 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2697 if (current->signal->tty != tty)
2702 return tiocsctty(tty, arg);
2704 return tiocgpgrp(tty, real_tty, p);
2706 return tiocspgrp(tty, real_tty, p);
2708 return tiocgsid(tty, real_tty, p);
2710 return put_user(tty->ldisc->ops->num, (int __user *)p);
2712 return tiocsetd(tty, p);
2714 if (!capable(CAP_SYS_ADMIN))
2720 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2721 return put_user(ret, (unsigned int __user *)p);
2726 case TIOCSBRK: /* Turn break on, unconditionally */
2727 if (tty->ops->break_ctl)
2728 return tty->ops->break_ctl(tty, -1);
2730 case TIOCCBRK: /* Turn break off, unconditionally */
2731 if (tty->ops->break_ctl)
2732 return tty->ops->break_ctl(tty, 0);
2734 case TCSBRK: /* SVID version: non-zero arg --> no break */
2735 /* non-zero arg means wait for all output data
2736 * to be sent (performed above) but don't send break.
2737 * This is used by the tcdrain() termios function.
2740 return send_break(tty, 250);
2742 case TCSBRKP: /* support for POSIX tcsendbreak() */
2743 return send_break(tty, arg ? arg*100 : 250);
2746 return tty_tiocmget(tty, p);
2750 return tty_tiocmset(tty, cmd, p);
2752 retval = tty_tiocgicount(tty, p);
2753 /* For the moment allow fall through to the old method */
2754 if (retval != -EINVAL)
2761 /* flush tty buffer and allow ldisc to process ioctl */
2762 tty_buffer_flush(tty);
2767 if (tty->ops->ioctl) {
2768 retval = (tty->ops->ioctl)(tty, cmd, arg);
2769 if (retval != -ENOIOCTLCMD)
2772 ld = tty_ldisc_ref_wait(tty);
2774 if (ld->ops->ioctl) {
2775 retval = ld->ops->ioctl(tty, file, cmd, arg);
2776 if (retval == -ENOIOCTLCMD)
2779 tty_ldisc_deref(ld);
2783 #ifdef CONFIG_COMPAT
2784 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2787 struct inode *inode = file->f_dentry->d_inode;
2788 struct tty_struct *tty = file_tty(file);
2789 struct tty_ldisc *ld;
2790 int retval = -ENOIOCTLCMD;
2792 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2795 if (tty->ops->compat_ioctl) {
2796 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2797 if (retval != -ENOIOCTLCMD)
2801 ld = tty_ldisc_ref_wait(tty);
2802 if (ld->ops->compat_ioctl)
2803 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2805 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2806 tty_ldisc_deref(ld);
2813 * This implements the "Secure Attention Key" --- the idea is to
2814 * prevent trojan horses by killing all processes associated with this
2815 * tty when the user hits the "Secure Attention Key". Required for
2816 * super-paranoid applications --- see the Orange Book for more details.
2818 * This code could be nicer; ideally it should send a HUP, wait a few
2819 * seconds, then send a INT, and then a KILL signal. But you then
2820 * have to coordinate with the init process, since all processes associated
2821 * with the current tty must be dead before the new getty is allowed
2824 * Now, if it would be correct ;-/ The current code has a nasty hole -
2825 * it doesn't catch files in flight. We may send the descriptor to ourselves
2826 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2828 * Nasty bug: do_SAK is being called in interrupt context. This can
2829 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2831 void __do_SAK(struct tty_struct *tty)
2836 struct task_struct *g, *p;
2837 struct pid *session;
2840 struct fdtable *fdt;
2844 session = tty->session;
2846 tty_ldisc_flush(tty);
2848 tty_driver_flush_buffer(tty);
2850 read_lock(&tasklist_lock);
2851 /* Kill the entire session */
2852 do_each_pid_task(session, PIDTYPE_SID, p) {
2853 printk(KERN_NOTICE "SAK: killed process %d"
2854 " (%s): task_session(p)==tty->session\n",
2855 task_pid_nr(p), p->comm);
2856 send_sig(SIGKILL, p, 1);
2857 } while_each_pid_task(session, PIDTYPE_SID, p);
2858 /* Now kill any processes that happen to have the
2861 do_each_thread(g, p) {
2862 if (p->signal->tty == tty) {
2863 printk(KERN_NOTICE "SAK: killed process %d"
2864 " (%s): task_session(p)==tty->session\n",
2865 task_pid_nr(p), p->comm);
2866 send_sig(SIGKILL, p, 1);
2872 * We don't take a ref to the file, so we must
2873 * hold ->file_lock instead.
2875 spin_lock(&p->files->file_lock);
2876 fdt = files_fdtable(p->files);
2877 for (i = 0; i < fdt->max_fds; i++) {
2878 filp = fcheck_files(p->files, i);
2881 if (filp->f_op->read == tty_read &&
2882 file_tty(filp) == tty) {
2883 printk(KERN_NOTICE "SAK: killed process %d"
2884 " (%s): fd#%d opened to the tty\n",
2885 task_pid_nr(p), p->comm, i);
2886 force_sig(SIGKILL, p);
2890 spin_unlock(&p->files->file_lock);
2893 } while_each_thread(g, p);
2894 read_unlock(&tasklist_lock);
2898 static void do_SAK_work(struct work_struct *work)
2900 struct tty_struct *tty =
2901 container_of(work, struct tty_struct, SAK_work);
2906 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2907 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2908 * the values which we write to it will be identical to the values which it
2909 * already has. --akpm
2911 void do_SAK(struct tty_struct *tty)
2915 schedule_work(&tty->SAK_work);
2918 EXPORT_SYMBOL(do_SAK);
2920 static int dev_match_devt(struct device *dev, void *data)
2923 return dev->devt == *devt;
2926 /* Must put_device() after it's unused! */
2927 static struct device *tty_get_device(struct tty_struct *tty)
2929 dev_t devt = tty_devnum(tty);
2930 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2935 * initialize_tty_struct
2936 * @tty: tty to initialize
2938 * This subroutine initializes a tty structure that has been newly
2941 * Locking: none - tty in question must not be exposed at this point
2944 void initialize_tty_struct(struct tty_struct *tty,
2945 struct tty_driver *driver, int idx)
2947 memset(tty, 0, sizeof(struct tty_struct));
2948 kref_init(&tty->kref);
2949 tty->magic = TTY_MAGIC;
2950 tty_ldisc_init(tty);
2951 tty->session = NULL;
2953 tty->overrun_time = jiffies;
2954 tty_buffer_init(tty);
2955 mutex_init(&tty->legacy_mutex);
2956 mutex_init(&tty->termios_mutex);
2957 mutex_init(&tty->ldisc_mutex);
2958 init_waitqueue_head(&tty->write_wait);
2959 init_waitqueue_head(&tty->read_wait);
2960 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2961 mutex_init(&tty->atomic_read_lock);
2962 mutex_init(&tty->atomic_write_lock);
2963 mutex_init(&tty->output_lock);
2964 mutex_init(&tty->echo_lock);
2965 spin_lock_init(&tty->read_lock);
2966 spin_lock_init(&tty->ctrl_lock);
2967 INIT_LIST_HEAD(&tty->tty_files);
2968 INIT_WORK(&tty->SAK_work, do_SAK_work);
2970 tty->driver = driver;
2971 tty->ops = driver->ops;
2973 tty_line_name(driver, idx, tty->name);
2974 tty->dev = tty_get_device(tty);
2978 * deinitialize_tty_struct
2979 * @tty: tty to deinitialize
2981 * This subroutine deinitializes a tty structure that has been newly
2982 * allocated but tty_release cannot be called on that yet.
2984 * Locking: none - tty in question must not be exposed at this point
2986 void deinitialize_tty_struct(struct tty_struct *tty)
2988 tty_ldisc_deinit(tty);
2992 * tty_put_char - write one character to a tty
2996 * Write one byte to the tty using the provided put_char method
2997 * if present. Returns the number of characters successfully output.
2999 * Note: the specific put_char operation in the driver layer may go
3000 * away soon. Don't call it directly, use this method
3003 int tty_put_char(struct tty_struct *tty, unsigned char ch)
3005 if (tty->ops->put_char)
3006 return tty->ops->put_char(tty, ch);
3007 return tty->ops->write(tty, &ch, 1);
3009 EXPORT_SYMBOL_GPL(tty_put_char);
3011 struct class *tty_class;
3013 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3014 unsigned int index, unsigned int count)
3016 /* init here, since reused cdevs cause crashes */
3017 cdev_init(&driver->cdevs[index], &tty_fops);
3018 driver->cdevs[index].owner = driver->owner;
3019 return cdev_add(&driver->cdevs[index], dev, count);
3023 * tty_register_device - register a tty device
3024 * @driver: the tty driver that describes the tty device
3025 * @index: the index in the tty driver for this tty device
3026 * @device: a struct device that is associated with this tty device.
3027 * This field is optional, if there is no known struct device
3028 * for this tty device it can be set to NULL safely.
3030 * Returns a pointer to the struct device for this tty device
3031 * (or ERR_PTR(-EFOO) on error).
3033 * This call is required to be made to register an individual tty device
3034 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3035 * that bit is not set, this function should not be called by a tty
3041 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3042 struct device *device)
3044 return tty_register_device_attr(driver, index, device, NULL, NULL);
3046 EXPORT_SYMBOL(tty_register_device);
3049 * tty_register_device_attr - register a tty device
3050 * @driver: the tty driver that describes the tty device
3051 * @index: the index in the tty driver for this tty device
3052 * @device: a struct device that is associated with this tty device.
3053 * This field is optional, if there is no known struct device
3054 * for this tty device it can be set to NULL safely.
3055 * @drvdata: Driver data to be set to device.
3056 * @attr_grp: Attribute group to be set on device.
3058 * Returns a pointer to the struct device for this tty device
3059 * (or ERR_PTR(-EFOO) on error).
3061 * This call is required to be made to register an individual tty device
3062 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3063 * that bit is not set, this function should not be called by a tty
3068 struct device *tty_register_device_attr(struct tty_driver *driver,
3069 unsigned index, struct device *device,
3071 const struct attribute_group **attr_grp)
3074 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3075 struct device *dev = NULL;
3076 int retval = -ENODEV;
3079 if (index >= driver->num) {
3080 printk(KERN_ERR "Attempt to register invalid tty line number "
3082 return ERR_PTR(-EINVAL);
3085 if (driver->type == TTY_DRIVER_TYPE_PTY)
3086 pty_line_name(driver, index, name);
3088 tty_line_name(driver, index, name);
3090 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3091 retval = tty_cdev_add(driver, devt, index, 1);
3097 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3104 dev->class = tty_class;
3105 dev->parent = device;
3106 dev_set_name(dev, "%s", name);
3107 dev->groups = attr_grp;
3108 dev_set_drvdata(dev, drvdata);
3110 retval = device_register(dev);
3119 cdev_del(&driver->cdevs[index]);
3120 return ERR_PTR(retval);
3122 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3125 * tty_unregister_device - unregister a tty device
3126 * @driver: the tty driver that describes the tty device
3127 * @index: the index in the tty driver for this tty device
3129 * If a tty device is registered with a call to tty_register_device() then
3130 * this function must be called when the tty device is gone.
3135 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3137 device_destroy(tty_class,
3138 MKDEV(driver->major, driver->minor_start) + index);
3139 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3140 cdev_del(&driver->cdevs[index]);
3142 EXPORT_SYMBOL(tty_unregister_device);
3145 * __tty_alloc_driver -- allocate tty driver
3146 * @lines: count of lines this driver can handle at most
3147 * @owner: module which is repsonsible for this driver
3148 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3150 * This should not be called directly, some of the provided macros should be
3151 * used instead. Use IS_ERR and friends on @retval.
3153 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3154 unsigned long flags)
3156 struct tty_driver *driver;
3157 unsigned int cdevs = 1;
3160 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3161 return ERR_PTR(-EINVAL);
3163 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3165 return ERR_PTR(-ENOMEM);
3167 kref_init(&driver->kref);
3168 driver->magic = TTY_DRIVER_MAGIC;
3169 driver->num = lines;
3170 driver->owner = owner;
3171 driver->flags = flags;
3173 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3174 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3176 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3178 if (!driver->ttys || !driver->termios) {
3184 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3185 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3187 if (!driver->ports) {
3194 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3195 if (!driver->cdevs) {
3202 kfree(driver->ports);
3203 kfree(driver->ttys);
3204 kfree(driver->termios);
3206 return ERR_PTR(err);
3208 EXPORT_SYMBOL(__tty_alloc_driver);
3210 static void destruct_tty_driver(struct kref *kref)
3212 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3214 struct ktermios *tp;
3216 if (driver->flags & TTY_DRIVER_INSTALLED) {
3218 * Free the termios and termios_locked structures because
3219 * we don't want to get memory leaks when modular tty
3220 * drivers are removed from the kernel.
3222 for (i = 0; i < driver->num; i++) {
3223 tp = driver->termios[i];
3225 driver->termios[i] = NULL;
3228 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3229 tty_unregister_device(driver, i);
3231 proc_tty_unregister_driver(driver);
3232 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3233 cdev_del(&driver->cdevs[0]);
3235 kfree(driver->cdevs);
3236 kfree(driver->ports);
3237 kfree(driver->termios);
3238 kfree(driver->ttys);
3242 void tty_driver_kref_put(struct tty_driver *driver)
3244 kref_put(&driver->kref, destruct_tty_driver);
3246 EXPORT_SYMBOL(tty_driver_kref_put);
3248 void tty_set_operations(struct tty_driver *driver,
3249 const struct tty_operations *op)
3253 EXPORT_SYMBOL(tty_set_operations);
3255 void put_tty_driver(struct tty_driver *d)
3257 tty_driver_kref_put(d);
3259 EXPORT_SYMBOL(put_tty_driver);
3262 * Called by a tty driver to register itself.
3264 int tty_register_driver(struct tty_driver *driver)
3271 if (!driver->major) {
3272 error = alloc_chrdev_region(&dev, driver->minor_start,
3273 driver->num, driver->name);
3275 driver->major = MAJOR(dev);
3276 driver->minor_start = MINOR(dev);
3279 dev = MKDEV(driver->major, driver->minor_start);
3280 error = register_chrdev_region(dev, driver->num, driver->name);
3285 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3286 error = tty_cdev_add(driver, dev, 0, driver->num);
3288 goto err_unreg_char;
3291 mutex_lock(&tty_mutex);
3292 list_add(&driver->tty_drivers, &tty_drivers);
3293 mutex_unlock(&tty_mutex);
3295 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3296 for (i = 0; i < driver->num; i++) {
3297 d = tty_register_device(driver, i, NULL);
3300 goto err_unreg_devs;
3304 proc_tty_register_driver(driver);
3305 driver->flags |= TTY_DRIVER_INSTALLED;
3309 for (i--; i >= 0; i--)
3310 tty_unregister_device(driver, i);
3312 mutex_lock(&tty_mutex);
3313 list_del(&driver->tty_drivers);
3314 mutex_unlock(&tty_mutex);
3317 unregister_chrdev_region(dev, driver->num);
3321 EXPORT_SYMBOL(tty_register_driver);
3324 * Called by a tty driver to unregister itself.
3326 int tty_unregister_driver(struct tty_driver *driver)
3330 if (driver->refcount)
3333 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3335 mutex_lock(&tty_mutex);
3336 list_del(&driver->tty_drivers);
3337 mutex_unlock(&tty_mutex);
3341 EXPORT_SYMBOL(tty_unregister_driver);
3343 dev_t tty_devnum(struct tty_struct *tty)
3345 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3347 EXPORT_SYMBOL(tty_devnum);
3349 void proc_clear_tty(struct task_struct *p)
3351 unsigned long flags;
3352 struct tty_struct *tty;
3353 spin_lock_irqsave(&p->sighand->siglock, flags);
3354 tty = p->signal->tty;
3355 p->signal->tty = NULL;
3356 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3360 /* Called under the sighand lock */
3362 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3365 unsigned long flags;
3366 /* We should not have a session or pgrp to put here but.... */
3367 spin_lock_irqsave(&tty->ctrl_lock, flags);
3368 put_pid(tty->session);
3370 tty->pgrp = get_pid(task_pgrp(tsk));
3371 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3372 tty->session = get_pid(task_session(tsk));
3373 if (tsk->signal->tty) {
3374 printk(KERN_DEBUG "tty not NULL!!\n");
3375 tty_kref_put(tsk->signal->tty);
3378 put_pid(tsk->signal->tty_old_pgrp);
3379 tsk->signal->tty = tty_kref_get(tty);
3380 tsk->signal->tty_old_pgrp = NULL;
3383 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3385 spin_lock_irq(&tsk->sighand->siglock);
3386 __proc_set_tty(tsk, tty);
3387 spin_unlock_irq(&tsk->sighand->siglock);
3390 struct tty_struct *get_current_tty(void)
3392 struct tty_struct *tty;
3393 unsigned long flags;
3395 spin_lock_irqsave(¤t->sighand->siglock, flags);
3396 tty = tty_kref_get(current->signal->tty);
3397 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3400 EXPORT_SYMBOL_GPL(get_current_tty);
3402 void tty_default_fops(struct file_operations *fops)
3408 * Initialize the console device. This is called *early*, so
3409 * we can't necessarily depend on lots of kernel help here.
3410 * Just do some early initializations, and do the complex setup
3413 void __init console_init(void)
3417 /* Setup the default TTY line discipline. */
3421 * set up the console device so that later boot sequences can
3422 * inform about problems etc..
3424 call = __con_initcall_start;
3425 while (call < __con_initcall_end) {
3431 static char *tty_devnode(struct device *dev, umode_t *mode)
3435 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3436 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3441 static int __init tty_class_init(void)
3443 tty_class = class_create(THIS_MODULE, "tty");
3444 if (IS_ERR(tty_class))
3445 return PTR_ERR(tty_class);
3446 tty_class->devnode = tty_devnode;
3450 postcore_initcall(tty_class_init);
3452 /* 3/2004 jmc: why do these devices exist? */
3453 static struct cdev tty_cdev, console_cdev;
3455 static ssize_t show_cons_active(struct device *dev,
3456 struct device_attribute *attr, char *buf)
3458 struct console *cs[16];
3464 for_each_console(c) {
3469 if ((c->flags & CON_ENABLED) == 0)
3472 if (i >= ARRAY_SIZE(cs))
3476 count += sprintf(buf + count, "%s%d%c",
3477 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3482 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3484 static struct device *consdev;
3486 void console_sysfs_notify(void)
3489 sysfs_notify(&consdev->kobj, NULL, "active");
3493 * Ok, now we can initialize the rest of the tty devices and can count
3494 * on memory allocations, interrupts etc..
3496 int __init tty_init(void)
3498 cdev_init(&tty_cdev, &tty_fops);
3499 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3500 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3501 panic("Couldn't register /dev/tty driver\n");
3502 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3504 cdev_init(&console_cdev, &console_fops);
3505 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3506 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3507 panic("Couldn't register /dev/console driver\n");
3508 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3510 if (IS_ERR(consdev))
3513 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3516 vty_init(&console_fops);