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);
1170 p = get_file(redirect);
1171 spin_unlock(&redirect_lock);
1175 res = vfs_write(p, buf, count, &p->f_pos);
1179 return tty_write(file, buf, count, ppos);
1182 static char ptychar[] = "pqrstuvwxyzabcde";
1185 * pty_line_name - generate name for a pty
1186 * @driver: the tty driver in use
1187 * @index: the minor number
1188 * @p: output buffer of at least 6 bytes
1190 * Generate a name from a driver reference and write it to the output
1195 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1197 int i = index + driver->name_base;
1198 /* ->name is initialized to "ttyp", but "tty" is expected */
1199 sprintf(p, "%s%c%x",
1200 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1201 ptychar[i >> 4 & 0xf], i & 0xf);
1205 * tty_line_name - generate name for a tty
1206 * @driver: the tty driver in use
1207 * @index: the minor number
1208 * @p: output buffer of at least 7 bytes
1210 * Generate a name from a driver reference and write it to the output
1215 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1217 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1218 strcpy(p, driver->name);
1220 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1224 * tty_driver_lookup_tty() - find an existing tty, if any
1225 * @driver: the driver for the tty
1226 * @idx: the minor number
1228 * Return the tty, if found or ERR_PTR() otherwise.
1230 * Locking: tty_mutex must be held. If tty is found, the mutex must
1231 * be held until the 'fast-open' is also done. Will change once we
1232 * have refcounting in the driver and per driver locking
1234 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1235 struct inode *inode, int idx)
1237 if (driver->ops->lookup)
1238 return driver->ops->lookup(driver, inode, idx);
1240 return driver->ttys[idx];
1244 * tty_init_termios - helper for termios setup
1245 * @tty: the tty to set up
1247 * Initialise the termios structures for this tty. Thus runs under
1248 * the tty_mutex currently so we can be relaxed about ordering.
1251 int tty_init_termios(struct tty_struct *tty)
1253 struct ktermios *tp;
1254 int idx = tty->index;
1256 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1257 tty->termios = tty->driver->init_termios;
1259 /* Check for lazy saved data */
1260 tp = tty->driver->termios[idx];
1264 tty->termios = tty->driver->init_termios;
1266 /* Compatibility until drivers always set this */
1267 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1268 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1271 EXPORT_SYMBOL_GPL(tty_init_termios);
1273 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1275 int ret = tty_init_termios(tty);
1279 tty_driver_kref_get(driver);
1281 driver->ttys[tty->index] = tty;
1284 EXPORT_SYMBOL_GPL(tty_standard_install);
1287 * tty_driver_install_tty() - install a tty entry in the driver
1288 * @driver: the driver for the tty
1291 * Install a tty object into the driver tables. The tty->index field
1292 * will be set by the time this is called. This method is responsible
1293 * for ensuring any need additional structures are allocated and
1296 * Locking: tty_mutex for now
1298 static int tty_driver_install_tty(struct tty_driver *driver,
1299 struct tty_struct *tty)
1301 return driver->ops->install ? driver->ops->install(driver, tty) :
1302 tty_standard_install(driver, tty);
1306 * tty_driver_remove_tty() - remove a tty from the driver tables
1307 * @driver: the driver for the tty
1308 * @idx: the minor number
1310 * Remvoe a tty object from the driver tables. The tty->index field
1311 * will be set by the time this is called.
1313 * Locking: tty_mutex for now
1315 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1317 if (driver->ops->remove)
1318 driver->ops->remove(driver, tty);
1320 driver->ttys[tty->index] = NULL;
1324 * tty_reopen() - fast re-open of an open tty
1325 * @tty - the tty to open
1327 * Return 0 on success, -errno on error.
1329 * Locking: tty_mutex must be held from the time the tty was found
1330 * till this open completes.
1332 static int tty_reopen(struct tty_struct *tty)
1334 struct tty_driver *driver = tty->driver;
1336 if (test_bit(TTY_CLOSING, &tty->flags) ||
1337 test_bit(TTY_HUPPING, &tty->flags) ||
1338 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1341 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1342 driver->subtype == PTY_TYPE_MASTER) {
1344 * special case for PTY masters: only one open permitted,
1345 * and the slave side open count is incremented as well.
1354 mutex_lock(&tty->ldisc_mutex);
1355 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1356 mutex_unlock(&tty->ldisc_mutex);
1362 * tty_init_dev - initialise a tty device
1363 * @driver: tty driver we are opening a device on
1364 * @idx: device index
1365 * @ret_tty: returned tty structure
1367 * Prepare a tty device. This may not be a "new" clean device but
1368 * could also be an active device. The pty drivers require special
1369 * handling because of this.
1372 * The function is called under the tty_mutex, which
1373 * protects us from the tty struct or driver itself going away.
1375 * On exit the tty device has the line discipline attached and
1376 * a reference count of 1. If a pair was created for pty/tty use
1377 * and the other was a pty master then it too has a reference count of 1.
1379 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1380 * failed open. The new code protects the open with a mutex, so it's
1381 * really quite straightforward. The mutex locking can probably be
1382 * relaxed for the (most common) case of reopening a tty.
1385 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1387 struct tty_struct *tty;
1391 * First time open is complex, especially for PTY devices.
1392 * This code guarantees that either everything succeeds and the
1393 * TTY is ready for operation, or else the table slots are vacated
1394 * and the allocated memory released. (Except that the termios
1395 * and locked termios may be retained.)
1398 if (!try_module_get(driver->owner))
1399 return ERR_PTR(-ENODEV);
1401 tty = alloc_tty_struct();
1404 goto err_module_put;
1406 initialize_tty_struct(tty, driver, idx);
1409 retval = tty_driver_install_tty(driver, tty);
1411 goto err_deinit_tty;
1414 tty->port = driver->ports[idx];
1416 WARN_RATELIMIT(!tty->port,
1417 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1418 __func__, tty->driver->name);
1421 * Structures all installed ... call the ldisc open routines.
1422 * If we fail here just call release_tty to clean up. No need
1423 * to decrement the use counts, as release_tty doesn't care.
1425 retval = tty_ldisc_setup(tty, tty->link);
1427 goto err_release_tty;
1428 /* Return the tty locked so that it cannot vanish under the caller */
1433 deinitialize_tty_struct(tty);
1434 free_tty_struct(tty);
1436 module_put(driver->owner);
1437 return ERR_PTR(retval);
1439 /* call the tty release_tty routine to clean out this slot */
1442 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1443 "clearing slot %d\n", idx);
1444 release_tty(tty, idx);
1445 return ERR_PTR(retval);
1448 void tty_free_termios(struct tty_struct *tty)
1450 struct ktermios *tp;
1451 int idx = tty->index;
1453 /* If the port is going to reset then it has no termios to save */
1454 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1457 /* Stash the termios data */
1458 tp = tty->driver->termios[idx];
1460 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1462 pr_warn("tty: no memory to save termios state.\n");
1465 tty->driver->termios[idx] = tp;
1469 EXPORT_SYMBOL(tty_free_termios);
1473 * release_one_tty - release tty structure memory
1474 * @kref: kref of tty we are obliterating
1476 * Releases memory associated with a tty structure, and clears out the
1477 * driver table slots. This function is called when a device is no longer
1478 * in use. It also gets called when setup of a device fails.
1481 * takes the file list lock internally when working on the list
1482 * of ttys that the driver keeps.
1484 * This method gets called from a work queue so that the driver private
1485 * cleanup ops can sleep (needed for USB at least)
1487 static void release_one_tty(struct work_struct *work)
1489 struct tty_struct *tty =
1490 container_of(work, struct tty_struct, hangup_work);
1491 struct tty_driver *driver = tty->driver;
1493 if (tty->ops->cleanup)
1494 tty->ops->cleanup(tty);
1497 tty_driver_kref_put(driver);
1498 module_put(driver->owner);
1500 spin_lock(&tty_files_lock);
1501 list_del_init(&tty->tty_files);
1502 spin_unlock(&tty_files_lock);
1505 put_pid(tty->session);
1506 free_tty_struct(tty);
1509 static void queue_release_one_tty(struct kref *kref)
1511 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1513 /* The hangup queue is now free so we can reuse it rather than
1514 waste a chunk of memory for each port */
1515 INIT_WORK(&tty->hangup_work, release_one_tty);
1516 schedule_work(&tty->hangup_work);
1520 * tty_kref_put - release a tty kref
1523 * Release a reference to a tty device and if need be let the kref
1524 * layer destruct the object for us
1527 void tty_kref_put(struct tty_struct *tty)
1530 kref_put(&tty->kref, queue_release_one_tty);
1532 EXPORT_SYMBOL(tty_kref_put);
1535 * release_tty - release tty structure memory
1537 * Release both @tty and a possible linked partner (think pty pair),
1538 * and decrement the refcount of the backing module.
1542 * takes the file list lock internally when working on the list
1543 * of ttys that the driver keeps.
1546 static void release_tty(struct tty_struct *tty, int idx)
1548 /* This should always be true but check for the moment */
1549 WARN_ON(tty->index != idx);
1550 WARN_ON(!mutex_is_locked(&tty_mutex));
1551 if (tty->ops->shutdown)
1552 tty->ops->shutdown(tty);
1553 tty_free_termios(tty);
1554 tty_driver_remove_tty(tty->driver, tty);
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->driver->other) {
1590 if (o_tty != tty->driver->other->ttys[idx]) {
1591 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1592 __func__, idx, tty->name);
1595 if (o_tty->link != tty) {
1596 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1605 * tty_release - vfs callback for close
1606 * @inode: inode of tty
1607 * @filp: file pointer for handle to tty
1609 * Called the last time each file handle is closed that references
1610 * this tty. There may however be several such references.
1613 * Takes bkl. See tty_release_dev
1615 * Even releasing the tty structures is a tricky business.. We have
1616 * to be very careful that the structures are all released at the
1617 * same time, as interrupts might otherwise get the wrong pointers.
1619 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1620 * lead to double frees or releasing memory still in use.
1623 int tty_release(struct inode *inode, struct file *filp)
1625 struct tty_struct *tty = file_tty(filp);
1626 struct tty_struct *o_tty;
1627 int pty_master, tty_closing, o_tty_closing, do_sleep;
1632 if (tty_paranoia_check(tty, inode, __func__))
1636 check_tty_count(tty, __func__);
1638 __tty_fasync(-1, filp, 0);
1641 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1642 tty->driver->subtype == PTY_TYPE_MASTER);
1643 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1644 /* Review: parallel close */
1647 if (tty_release_checks(tty, o_tty, idx)) {
1652 #ifdef TTY_DEBUG_HANGUP
1653 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1654 tty_name(tty, buf), tty->count);
1657 if (tty->ops->close)
1658 tty->ops->close(tty, filp);
1662 * Sanity check: if tty->count is going to zero, there shouldn't be
1663 * any waiters on tty->read_wait or tty->write_wait. We test the
1664 * wait queues and kick everyone out _before_ actually starting to
1665 * close. This ensures that we won't block while releasing the tty
1668 * The test for the o_tty closing is necessary, since the master and
1669 * slave sides may close in any order. If the slave side closes out
1670 * first, its count will be one, since the master side holds an open.
1671 * Thus this test wouldn't be triggered at the time the slave closes,
1674 * Note that it's possible for the tty to be opened again while we're
1675 * flushing out waiters. By recalculating the closing flags before
1676 * each iteration we avoid any problems.
1679 /* Guard against races with tty->count changes elsewhere and
1680 opens on /dev/tty */
1682 mutex_lock(&tty_mutex);
1683 tty_lock_pair(tty, o_tty);
1684 tty_closing = tty->count <= 1;
1685 o_tty_closing = o_tty &&
1686 (o_tty->count <= (pty_master ? 1 : 0));
1690 if (waitqueue_active(&tty->read_wait)) {
1691 wake_up_poll(&tty->read_wait, POLLIN);
1694 if (waitqueue_active(&tty->write_wait)) {
1695 wake_up_poll(&tty->write_wait, POLLOUT);
1699 if (o_tty_closing) {
1700 if (waitqueue_active(&o_tty->read_wait)) {
1701 wake_up_poll(&o_tty->read_wait, POLLIN);
1704 if (waitqueue_active(&o_tty->write_wait)) {
1705 wake_up_poll(&o_tty->write_wait, POLLOUT);
1712 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1713 __func__, tty_name(tty, buf));
1714 tty_unlock_pair(tty, o_tty);
1715 mutex_unlock(&tty_mutex);
1720 * The closing flags are now consistent with the open counts on
1721 * both sides, and we've completed the last operation that could
1722 * block, so it's safe to proceed with closing.
1724 * We must *not* drop the tty_mutex until we ensure that a further
1725 * entry into tty_open can not pick up this tty.
1728 if (--o_tty->count < 0) {
1729 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1730 __func__, o_tty->count, tty_name(o_tty, buf));
1734 if (--tty->count < 0) {
1735 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1736 __func__, tty->count, tty_name(tty, buf));
1741 * We've decremented tty->count, so we need to remove this file
1742 * descriptor off the tty->tty_files list; this serves two
1744 * - check_tty_count sees the correct number of file descriptors
1745 * associated with this tty.
1746 * - do_tty_hangup no longer sees this file descriptor as
1747 * something that needs to be handled for hangups.
1752 * Perform some housekeeping before deciding whether to return.
1754 * Set the TTY_CLOSING flag if this was the last open. In the
1755 * case of a pty we may have to wait around for the other side
1756 * to close, and TTY_CLOSING makes sure we can't be reopened.
1759 set_bit(TTY_CLOSING, &tty->flags);
1761 set_bit(TTY_CLOSING, &o_tty->flags);
1764 * If _either_ side is closing, make sure there aren't any
1765 * processes that still think tty or o_tty is their controlling
1768 if (tty_closing || o_tty_closing) {
1769 read_lock(&tasklist_lock);
1770 session_clear_tty(tty->session);
1772 session_clear_tty(o_tty->session);
1773 read_unlock(&tasklist_lock);
1776 mutex_unlock(&tty_mutex);
1777 tty_unlock_pair(tty, o_tty);
1778 /* At this point the TTY_CLOSING flag should ensure a dead tty
1779 cannot be re-opened by a racing opener */
1781 /* check whether both sides are closing ... */
1782 if (!tty_closing || (o_tty && !o_tty_closing))
1785 #ifdef TTY_DEBUG_HANGUP
1786 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1789 * Ask the line discipline code to release its structures
1791 tty_ldisc_release(tty, o_tty);
1793 * The release_tty function takes care of the details of clearing
1794 * the slots and preserving the termios structure. The tty_unlock_pair
1795 * should be safe as we keep a kref while the tty is locked (so the
1796 * unlock never unlocks a freed tty).
1798 mutex_lock(&tty_mutex);
1799 release_tty(tty, idx);
1800 mutex_unlock(&tty_mutex);
1802 /* Make this pty number available for reallocation */
1804 devpts_kill_index(inode, idx);
1809 * tty_open_current_tty - get tty of current task for open
1810 * @device: device number
1811 * @filp: file pointer to tty
1812 * @return: tty of the current task iff @device is /dev/tty
1814 * We cannot return driver and index like for the other nodes because
1815 * devpts will not work then. It expects inodes to be from devpts FS.
1817 * We need to move to returning a refcounted object from all the lookup
1818 * paths including this one.
1820 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1822 struct tty_struct *tty;
1824 if (device != MKDEV(TTYAUX_MAJOR, 0))
1827 tty = get_current_tty();
1829 return ERR_PTR(-ENXIO);
1831 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1834 /* FIXME: we put a reference and return a TTY! */
1835 /* This is only safe because the caller holds tty_mutex */
1840 * tty_lookup_driver - lookup a tty driver for a given device file
1841 * @device: device number
1842 * @filp: file pointer to tty
1843 * @noctty: set if the device should not become a controlling tty
1844 * @index: index for the device in the @return driver
1845 * @return: driver for this inode (with increased refcount)
1847 * If @return is not erroneous, the caller is responsible to decrement the
1848 * refcount by tty_driver_kref_put.
1850 * Locking: tty_mutex protects get_tty_driver
1852 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1853 int *noctty, int *index)
1855 struct tty_driver *driver;
1859 case MKDEV(TTY_MAJOR, 0): {
1860 extern struct tty_driver *console_driver;
1861 driver = tty_driver_kref_get(console_driver);
1862 *index = fg_console;
1867 case MKDEV(TTYAUX_MAJOR, 1): {
1868 struct tty_driver *console_driver = console_device(index);
1869 if (console_driver) {
1870 driver = tty_driver_kref_get(console_driver);
1872 /* Don't let /dev/console block */
1873 filp->f_flags |= O_NONBLOCK;
1878 return ERR_PTR(-ENODEV);
1881 driver = get_tty_driver(device, index);
1883 return ERR_PTR(-ENODEV);
1890 * tty_open - open a tty device
1891 * @inode: inode of device file
1892 * @filp: file pointer to tty
1894 * tty_open and tty_release keep up the tty count that contains the
1895 * number of opens done on a tty. We cannot use the inode-count, as
1896 * different inodes might point to the same tty.
1898 * Open-counting is needed for pty masters, as well as for keeping
1899 * track of serial lines: DTR is dropped when the last close happens.
1900 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1902 * The termios state of a pty is reset on first open so that
1903 * settings don't persist across reuse.
1905 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1906 * tty->count should protect the rest.
1907 * ->siglock protects ->signal/->sighand
1909 * Note: the tty_unlock/lock cases without a ref are only safe due to
1913 static int tty_open(struct inode *inode, struct file *filp)
1915 struct tty_struct *tty;
1917 struct tty_driver *driver = NULL;
1919 dev_t device = inode->i_rdev;
1920 unsigned saved_flags = filp->f_flags;
1922 nonseekable_open(inode, filp);
1925 retval = tty_alloc_file(filp);
1929 noctty = filp->f_flags & O_NOCTTY;
1933 mutex_lock(&tty_mutex);
1934 /* This is protected by the 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);
1956 retval = tty_reopen(tty);
1959 tty = ERR_PTR(retval);
1961 } else /* Returns with the tty_lock held for now */
1962 tty = tty_init_dev(driver, index);
1964 mutex_unlock(&tty_mutex);
1966 tty_driver_kref_put(driver);
1968 retval = PTR_ERR(tty);
1972 tty_add_file(tty, filp);
1974 check_tty_count(tty, __func__);
1975 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1976 tty->driver->subtype == PTY_TYPE_MASTER)
1978 #ifdef TTY_DEBUG_HANGUP
1979 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1982 retval = tty->ops->open(tty, filp);
1985 filp->f_flags = saved_flags;
1987 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1988 !capable(CAP_SYS_ADMIN))
1992 #ifdef TTY_DEBUG_HANGUP
1993 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
1996 tty_unlock(tty); /* need to call tty_release without BTM */
1997 tty_release(inode, filp);
1998 if (retval != -ERESTARTSYS)
2001 if (signal_pending(current))
2006 * Need to reset f_op in case a hangup happened.
2008 if (filp->f_op == &hung_up_tty_fops)
2009 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);
2028 mutex_unlock(&tty_mutex);
2029 /* after locks to avoid deadlock */
2030 if (!IS_ERR_OR_NULL(driver))
2031 tty_driver_kref_put(driver);
2033 tty_free_file(filp);
2040 * tty_poll - check tty status
2041 * @filp: file being polled
2042 * @wait: poll wait structures to update
2044 * Call the line discipline polling method to obtain the poll
2045 * status of the device.
2047 * Locking: locks called line discipline but ldisc poll method
2048 * may be re-entered freely by other callers.
2051 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2053 struct tty_struct *tty = file_tty(filp);
2054 struct tty_ldisc *ld;
2057 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2060 ld = tty_ldisc_ref_wait(tty);
2062 ret = (ld->ops->poll)(tty, filp, wait);
2063 tty_ldisc_deref(ld);
2067 static int __tty_fasync(int fd, struct file *filp, int on)
2069 struct tty_struct *tty = file_tty(filp);
2070 unsigned long flags;
2073 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2076 retval = fasync_helper(fd, filp, on, &tty->fasync);
2083 if (!waitqueue_active(&tty->read_wait))
2084 tty->minimum_to_wake = 1;
2085 spin_lock_irqsave(&tty->ctrl_lock, flags);
2088 type = PIDTYPE_PGID;
2090 pid = task_pid(current);
2094 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2095 retval = __f_setown(filp, pid, type, 0);
2100 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2101 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2108 static int tty_fasync(int fd, struct file *filp, int on)
2110 struct tty_struct *tty = file_tty(filp);
2114 retval = __tty_fasync(fd, filp, on);
2121 * tiocsti - fake input character
2122 * @tty: tty to fake input into
2123 * @p: pointer to character
2125 * Fake input to a tty device. Does the necessary locking and
2128 * FIXME: does not honour flow control ??
2131 * Called functions take tty_ldisc_lock
2132 * current->signal->tty check is safe without locks
2134 * FIXME: may race normal receive processing
2137 static int tiocsti(struct tty_struct *tty, char __user *p)
2140 struct tty_ldisc *ld;
2142 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2144 if (get_user(ch, p))
2146 tty_audit_tiocsti(tty, ch);
2147 ld = tty_ldisc_ref_wait(tty);
2148 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2149 tty_ldisc_deref(ld);
2154 * tiocgwinsz - implement window query ioctl
2156 * @arg: user buffer for result
2158 * Copies the kernel idea of the window size into the user buffer.
2160 * Locking: tty->termios_mutex is taken to ensure the winsize data
2164 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2168 mutex_lock(&tty->termios_mutex);
2169 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2170 mutex_unlock(&tty->termios_mutex);
2172 return err ? -EFAULT: 0;
2176 * tty_do_resize - resize event
2177 * @tty: tty being resized
2178 * @rows: rows (character)
2179 * @cols: cols (character)
2181 * Update the termios variables and send the necessary signals to
2182 * peform a terminal resize correctly
2185 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2188 unsigned long flags;
2191 mutex_lock(&tty->termios_mutex);
2192 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2194 /* Get the PID values and reference them so we can
2195 avoid holding the tty ctrl lock while sending signals */
2196 spin_lock_irqsave(&tty->ctrl_lock, flags);
2197 pgrp = get_pid(tty->pgrp);
2198 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2201 kill_pgrp(pgrp, SIGWINCH, 1);
2206 mutex_unlock(&tty->termios_mutex);
2211 * tiocswinsz - implement window size set ioctl
2212 * @tty; tty side of tty
2213 * @arg: user buffer for result
2215 * Copies the user idea of the window size to the kernel. Traditionally
2216 * this is just advisory information but for the Linux console it
2217 * actually has driver level meaning and triggers a VC resize.
2220 * Driver dependent. The default do_resize method takes the
2221 * tty termios mutex and ctrl_lock. The console takes its own lock
2222 * then calls into the default method.
2225 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2227 struct winsize tmp_ws;
2228 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2231 if (tty->ops->resize)
2232 return tty->ops->resize(tty, &tmp_ws);
2234 return tty_do_resize(tty, &tmp_ws);
2238 * tioccons - allow admin to move logical console
2239 * @file: the file to become console
2241 * Allow the administrator to move the redirected console device
2243 * Locking: uses redirect_lock to guard the redirect information
2246 static int tioccons(struct file *file)
2248 if (!capable(CAP_SYS_ADMIN))
2250 if (file->f_op->write == redirected_tty_write) {
2252 spin_lock(&redirect_lock);
2255 spin_unlock(&redirect_lock);
2260 spin_lock(&redirect_lock);
2262 spin_unlock(&redirect_lock);
2265 redirect = get_file(file);
2266 spin_unlock(&redirect_lock);
2271 * fionbio - non blocking ioctl
2272 * @file: file to set blocking value
2273 * @p: user parameter
2275 * Historical tty interfaces had a blocking control ioctl before
2276 * the generic functionality existed. This piece of history is preserved
2277 * in the expected tty API of posix OS's.
2279 * Locking: none, the open file handle ensures it won't go away.
2282 static int fionbio(struct file *file, int __user *p)
2286 if (get_user(nonblock, p))
2289 spin_lock(&file->f_lock);
2291 file->f_flags |= O_NONBLOCK;
2293 file->f_flags &= ~O_NONBLOCK;
2294 spin_unlock(&file->f_lock);
2299 * tiocsctty - set controlling tty
2300 * @tty: tty structure
2301 * @arg: user argument
2303 * This ioctl is used to manage job control. It permits a session
2304 * leader to set this tty as the controlling tty for the session.
2307 * Takes tty_mutex() to protect tty instance
2308 * Takes tasklist_lock internally to walk sessions
2309 * Takes ->siglock() when updating signal->tty
2312 static int tiocsctty(struct tty_struct *tty, int arg)
2315 if (current->signal->leader && (task_session(current) == tty->session))
2318 mutex_lock(&tty_mutex);
2320 * The process must be a session leader and
2321 * not have a controlling tty already.
2323 if (!current->signal->leader || current->signal->tty) {
2330 * This tty is already the controlling
2331 * tty for another session group!
2333 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2337 read_lock(&tasklist_lock);
2338 session_clear_tty(tty->session);
2339 read_unlock(&tasklist_lock);
2345 proc_set_tty(current, tty);
2347 mutex_unlock(&tty_mutex);
2352 * tty_get_pgrp - return a ref counted pgrp pid
2355 * Returns a refcounted instance of the pid struct for the process
2356 * group controlling the tty.
2359 struct pid *tty_get_pgrp(struct tty_struct *tty)
2361 unsigned long flags;
2364 spin_lock_irqsave(&tty->ctrl_lock, flags);
2365 pgrp = get_pid(tty->pgrp);
2366 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2370 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2373 * tiocgpgrp - get process group
2374 * @tty: tty passed by user
2375 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2378 * Obtain the process group of the tty. If there is no process group
2381 * Locking: none. Reference to current->signal->tty is safe.
2384 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2389 * (tty == real_tty) is a cheap way of
2390 * testing if the tty is NOT a master pty.
2392 if (tty == real_tty && current->signal->tty != real_tty)
2394 pid = tty_get_pgrp(real_tty);
2395 ret = put_user(pid_vnr(pid), p);
2401 * tiocspgrp - attempt to set process group
2402 * @tty: tty passed by user
2403 * @real_tty: tty side device matching tty passed by user
2406 * Set the process group of the tty to the session passed. Only
2407 * permitted where the tty session is our session.
2409 * Locking: RCU, ctrl lock
2412 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2416 int retval = tty_check_change(real_tty);
2417 unsigned long flags;
2423 if (!current->signal->tty ||
2424 (current->signal->tty != real_tty) ||
2425 (real_tty->session != task_session(current)))
2427 if (get_user(pgrp_nr, p))
2432 pgrp = find_vpid(pgrp_nr);
2437 if (session_of_pgrp(pgrp) != task_session(current))
2440 spin_lock_irqsave(&tty->ctrl_lock, flags);
2441 put_pid(real_tty->pgrp);
2442 real_tty->pgrp = get_pid(pgrp);
2443 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2450 * tiocgsid - get session id
2451 * @tty: tty passed by user
2452 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2453 * @p: pointer to returned session id
2455 * Obtain the session id of the tty. If there is no session
2458 * Locking: none. Reference to current->signal->tty is safe.
2461 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2464 * (tty == real_tty) is a cheap way of
2465 * testing if the tty is NOT a master pty.
2467 if (tty == real_tty && current->signal->tty != real_tty)
2469 if (!real_tty->session)
2471 return put_user(pid_vnr(real_tty->session), p);
2475 * tiocsetd - set line discipline
2477 * @p: pointer to user data
2479 * Set the line discipline according to user request.
2481 * Locking: see tty_set_ldisc, this function is just a helper
2484 static int tiocsetd(struct tty_struct *tty, int __user *p)
2489 if (get_user(ldisc, p))
2492 ret = tty_set_ldisc(tty, ldisc);
2498 * send_break - performed time break
2499 * @tty: device to break on
2500 * @duration: timeout in mS
2502 * Perform a timed break on hardware that lacks its own driver level
2503 * timed break functionality.
2506 * atomic_write_lock serializes
2510 static int send_break(struct tty_struct *tty, unsigned int duration)
2514 if (tty->ops->break_ctl == NULL)
2517 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2518 retval = tty->ops->break_ctl(tty, duration);
2520 /* Do the work ourselves */
2521 if (tty_write_lock(tty, 0) < 0)
2523 retval = tty->ops->break_ctl(tty, -1);
2526 if (!signal_pending(current))
2527 msleep_interruptible(duration);
2528 retval = tty->ops->break_ctl(tty, 0);
2530 tty_write_unlock(tty);
2531 if (signal_pending(current))
2538 * tty_tiocmget - get modem status
2540 * @file: user file pointer
2541 * @p: pointer to result
2543 * Obtain the modem status bits from the tty driver if the feature
2544 * is supported. Return -EINVAL if it is not available.
2546 * Locking: none (up to the driver)
2549 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2551 int retval = -EINVAL;
2553 if (tty->ops->tiocmget) {
2554 retval = tty->ops->tiocmget(tty);
2557 retval = put_user(retval, p);
2563 * tty_tiocmset - set modem status
2565 * @cmd: command - clear bits, set bits or set all
2566 * @p: pointer to desired bits
2568 * Set the modem status bits from the tty driver if the feature
2569 * is supported. Return -EINVAL if it is not available.
2571 * Locking: none (up to the driver)
2574 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2578 unsigned int set, clear, val;
2580 if (tty->ops->tiocmset == NULL)
2583 retval = get_user(val, p);
2599 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2600 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2601 return tty->ops->tiocmset(tty, set, clear);
2604 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2606 int retval = -EINVAL;
2607 struct serial_icounter_struct icount;
2608 memset(&icount, 0, sizeof(icount));
2609 if (tty->ops->get_icount)
2610 retval = tty->ops->get_icount(tty, &icount);
2613 if (copy_to_user(arg, &icount, sizeof(icount)))
2618 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2620 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2621 tty->driver->subtype == PTY_TYPE_MASTER)
2625 EXPORT_SYMBOL(tty_pair_get_tty);
2627 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2629 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2630 tty->driver->subtype == PTY_TYPE_MASTER)
2634 EXPORT_SYMBOL(tty_pair_get_pty);
2637 * Split this up, as gcc can choke on it otherwise..
2639 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2641 struct tty_struct *tty = file_tty(file);
2642 struct tty_struct *real_tty;
2643 void __user *p = (void __user *)arg;
2645 struct tty_ldisc *ld;
2646 struct inode *inode = file->f_dentry->d_inode;
2648 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2651 real_tty = tty_pair_get_tty(tty);
2654 * Factor out some common prep work
2662 retval = tty_check_change(tty);
2665 if (cmd != TIOCCBRK) {
2666 tty_wait_until_sent(tty, 0);
2667 if (signal_pending(current))
2678 return tiocsti(tty, p);
2680 return tiocgwinsz(real_tty, p);
2682 return tiocswinsz(real_tty, p);
2684 return real_tty != tty ? -EINVAL : tioccons(file);
2686 return fionbio(file, p);
2688 set_bit(TTY_EXCLUSIVE, &tty->flags);
2691 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2694 if (current->signal->tty != tty)
2699 return tiocsctty(tty, arg);
2701 return tiocgpgrp(tty, real_tty, p);
2703 return tiocspgrp(tty, real_tty, p);
2705 return tiocgsid(tty, real_tty, p);
2707 return put_user(tty->ldisc->ops->num, (int __user *)p);
2709 return tiocsetd(tty, p);
2711 if (!capable(CAP_SYS_ADMIN))
2717 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2718 return put_user(ret, (unsigned int __user *)p);
2723 case TIOCSBRK: /* Turn break on, unconditionally */
2724 if (tty->ops->break_ctl)
2725 return tty->ops->break_ctl(tty, -1);
2727 case TIOCCBRK: /* Turn break off, unconditionally */
2728 if (tty->ops->break_ctl)
2729 return tty->ops->break_ctl(tty, 0);
2731 case TCSBRK: /* SVID version: non-zero arg --> no break */
2732 /* non-zero arg means wait for all output data
2733 * to be sent (performed above) but don't send break.
2734 * This is used by the tcdrain() termios function.
2737 return send_break(tty, 250);
2739 case TCSBRKP: /* support for POSIX tcsendbreak() */
2740 return send_break(tty, arg ? arg*100 : 250);
2743 return tty_tiocmget(tty, p);
2747 return tty_tiocmset(tty, cmd, p);
2749 retval = tty_tiocgicount(tty, p);
2750 /* For the moment allow fall through to the old method */
2751 if (retval != -EINVAL)
2758 /* flush tty buffer and allow ldisc to process ioctl */
2759 tty_buffer_flush(tty);
2764 if (tty->ops->ioctl) {
2765 retval = (tty->ops->ioctl)(tty, cmd, arg);
2766 if (retval != -ENOIOCTLCMD)
2769 ld = tty_ldisc_ref_wait(tty);
2771 if (ld->ops->ioctl) {
2772 retval = ld->ops->ioctl(tty, file, cmd, arg);
2773 if (retval == -ENOIOCTLCMD)
2776 tty_ldisc_deref(ld);
2780 #ifdef CONFIG_COMPAT
2781 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2784 struct inode *inode = file->f_dentry->d_inode;
2785 struct tty_struct *tty = file_tty(file);
2786 struct tty_ldisc *ld;
2787 int retval = -ENOIOCTLCMD;
2789 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2792 if (tty->ops->compat_ioctl) {
2793 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2794 if (retval != -ENOIOCTLCMD)
2798 ld = tty_ldisc_ref_wait(tty);
2799 if (ld->ops->compat_ioctl)
2800 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2802 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2803 tty_ldisc_deref(ld);
2809 static int this_tty(const void *t, struct file *file, unsigned fd)
2811 if (likely(file->f_op->read != tty_read))
2813 return file_tty(file) != t ? 0 : fd + 1;
2817 * This implements the "Secure Attention Key" --- the idea is to
2818 * prevent trojan horses by killing all processes associated with this
2819 * tty when the user hits the "Secure Attention Key". Required for
2820 * super-paranoid applications --- see the Orange Book for more details.
2822 * This code could be nicer; ideally it should send a HUP, wait a few
2823 * seconds, then send a INT, and then a KILL signal. But you then
2824 * have to coordinate with the init process, since all processes associated
2825 * with the current tty must be dead before the new getty is allowed
2828 * Now, if it would be correct ;-/ The current code has a nasty hole -
2829 * it doesn't catch files in flight. We may send the descriptor to ourselves
2830 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2832 * Nasty bug: do_SAK is being called in interrupt context. This can
2833 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2835 void __do_SAK(struct tty_struct *tty)
2840 struct task_struct *g, *p;
2841 struct pid *session;
2846 session = tty->session;
2848 tty_ldisc_flush(tty);
2850 tty_driver_flush_buffer(tty);
2852 read_lock(&tasklist_lock);
2853 /* Kill the entire session */
2854 do_each_pid_task(session, PIDTYPE_SID, p) {
2855 printk(KERN_NOTICE "SAK: killed process %d"
2856 " (%s): task_session(p)==tty->session\n",
2857 task_pid_nr(p), p->comm);
2858 send_sig(SIGKILL, p, 1);
2859 } while_each_pid_task(session, PIDTYPE_SID, p);
2860 /* Now kill any processes that happen to have the
2863 do_each_thread(g, p) {
2864 if (p->signal->tty == tty) {
2865 printk(KERN_NOTICE "SAK: killed process %d"
2866 " (%s): task_session(p)==tty->session\n",
2867 task_pid_nr(p), p->comm);
2868 send_sig(SIGKILL, p, 1);
2872 i = iterate_fd(p->files, 0, this_tty, tty);
2874 printk(KERN_NOTICE "SAK: killed process %d"
2875 " (%s): fd#%d opened to the tty\n",
2876 task_pid_nr(p), p->comm, i - 1);
2877 force_sig(SIGKILL, p);
2880 } while_each_thread(g, p);
2881 read_unlock(&tasklist_lock);
2885 static void do_SAK_work(struct work_struct *work)
2887 struct tty_struct *tty =
2888 container_of(work, struct tty_struct, SAK_work);
2893 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2894 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2895 * the values which we write to it will be identical to the values which it
2896 * already has. --akpm
2898 void do_SAK(struct tty_struct *tty)
2902 schedule_work(&tty->SAK_work);
2905 EXPORT_SYMBOL(do_SAK);
2907 static int dev_match_devt(struct device *dev, void *data)
2910 return dev->devt == *devt;
2913 /* Must put_device() after it's unused! */
2914 static struct device *tty_get_device(struct tty_struct *tty)
2916 dev_t devt = tty_devnum(tty);
2917 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2922 * initialize_tty_struct
2923 * @tty: tty to initialize
2925 * This subroutine initializes a tty structure that has been newly
2928 * Locking: none - tty in question must not be exposed at this point
2931 void initialize_tty_struct(struct tty_struct *tty,
2932 struct tty_driver *driver, int idx)
2934 memset(tty, 0, sizeof(struct tty_struct));
2935 kref_init(&tty->kref);
2936 tty->magic = TTY_MAGIC;
2937 tty_ldisc_init(tty);
2938 tty->session = NULL;
2940 tty->overrun_time = jiffies;
2941 tty_buffer_init(tty);
2942 mutex_init(&tty->legacy_mutex);
2943 mutex_init(&tty->termios_mutex);
2944 mutex_init(&tty->ldisc_mutex);
2945 init_waitqueue_head(&tty->write_wait);
2946 init_waitqueue_head(&tty->read_wait);
2947 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2948 mutex_init(&tty->atomic_read_lock);
2949 mutex_init(&tty->atomic_write_lock);
2950 mutex_init(&tty->output_lock);
2951 mutex_init(&tty->echo_lock);
2952 spin_lock_init(&tty->read_lock);
2953 spin_lock_init(&tty->ctrl_lock);
2954 INIT_LIST_HEAD(&tty->tty_files);
2955 INIT_WORK(&tty->SAK_work, do_SAK_work);
2957 tty->driver = driver;
2958 tty->ops = driver->ops;
2960 tty_line_name(driver, idx, tty->name);
2961 tty->dev = tty_get_device(tty);
2965 * deinitialize_tty_struct
2966 * @tty: tty to deinitialize
2968 * This subroutine deinitializes a tty structure that has been newly
2969 * allocated but tty_release cannot be called on that yet.
2971 * Locking: none - tty in question must not be exposed at this point
2973 void deinitialize_tty_struct(struct tty_struct *tty)
2975 tty_ldisc_deinit(tty);
2979 * tty_put_char - write one character to a tty
2983 * Write one byte to the tty using the provided put_char method
2984 * if present. Returns the number of characters successfully output.
2986 * Note: the specific put_char operation in the driver layer may go
2987 * away soon. Don't call it directly, use this method
2990 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2992 if (tty->ops->put_char)
2993 return tty->ops->put_char(tty, ch);
2994 return tty->ops->write(tty, &ch, 1);
2996 EXPORT_SYMBOL_GPL(tty_put_char);
2998 struct class *tty_class;
3000 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
3001 unsigned int index, unsigned int count)
3003 /* init here, since reused cdevs cause crashes */
3004 cdev_init(&driver->cdevs[index], &tty_fops);
3005 driver->cdevs[index].owner = driver->owner;
3006 return cdev_add(&driver->cdevs[index], dev, count);
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)
3031 return tty_register_device_attr(driver, index, device, NULL, NULL);
3033 EXPORT_SYMBOL(tty_register_device);
3035 static void tty_device_create_release(struct device *dev)
3037 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3042 * tty_register_device_attr - register a tty device
3043 * @driver: the tty driver that describes the tty device
3044 * @index: the index in the tty driver for this tty device
3045 * @device: a struct device that is associated with this tty device.
3046 * This field is optional, if there is no known struct device
3047 * for this tty device it can be set to NULL safely.
3048 * @drvdata: Driver data to be set to device.
3049 * @attr_grp: Attribute group to be set on device.
3051 * Returns a pointer to the struct device for this tty device
3052 * (or ERR_PTR(-EFOO) on error).
3054 * This call is required to be made to register an individual tty device
3055 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3056 * that bit is not set, this function should not be called by a tty
3061 struct device *tty_register_device_attr(struct tty_driver *driver,
3062 unsigned index, struct device *device,
3064 const struct attribute_group **attr_grp)
3067 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3068 struct device *dev = NULL;
3069 int retval = -ENODEV;
3072 if (index >= driver->num) {
3073 printk(KERN_ERR "Attempt to register invalid tty line number "
3075 return ERR_PTR(-EINVAL);
3078 if (driver->type == TTY_DRIVER_TYPE_PTY)
3079 pty_line_name(driver, index, name);
3081 tty_line_name(driver, index, name);
3083 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3084 retval = tty_cdev_add(driver, devt, index, 1);
3090 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3097 dev->class = tty_class;
3098 dev->parent = device;
3099 dev->release = tty_device_create_release;
3100 dev_set_name(dev, "%s", name);
3101 dev->groups = attr_grp;
3102 dev_set_drvdata(dev, drvdata);
3104 retval = device_register(dev);
3113 cdev_del(&driver->cdevs[index]);
3114 return ERR_PTR(retval);
3116 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3119 * tty_unregister_device - unregister a tty device
3120 * @driver: the tty driver that describes the tty device
3121 * @index: the index in the tty driver for this tty device
3123 * If a tty device is registered with a call to tty_register_device() then
3124 * this function must be called when the tty device is gone.
3129 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3131 device_destroy(tty_class,
3132 MKDEV(driver->major, driver->minor_start) + index);
3133 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3134 cdev_del(&driver->cdevs[index]);
3136 EXPORT_SYMBOL(tty_unregister_device);
3139 * __tty_alloc_driver -- allocate tty driver
3140 * @lines: count of lines this driver can handle at most
3141 * @owner: module which is repsonsible for this driver
3142 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3144 * This should not be called directly, some of the provided macros should be
3145 * used instead. Use IS_ERR and friends on @retval.
3147 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3148 unsigned long flags)
3150 struct tty_driver *driver;
3151 unsigned int cdevs = 1;
3154 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3155 return ERR_PTR(-EINVAL);
3157 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3159 return ERR_PTR(-ENOMEM);
3161 kref_init(&driver->kref);
3162 driver->magic = TTY_DRIVER_MAGIC;
3163 driver->num = lines;
3164 driver->owner = owner;
3165 driver->flags = flags;
3167 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3168 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3170 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3172 if (!driver->ttys || !driver->termios) {
3178 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3179 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3181 if (!driver->ports) {
3188 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3189 if (!driver->cdevs) {
3196 kfree(driver->ports);
3197 kfree(driver->ttys);
3198 kfree(driver->termios);
3200 return ERR_PTR(err);
3202 EXPORT_SYMBOL(__tty_alloc_driver);
3204 static void destruct_tty_driver(struct kref *kref)
3206 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3208 struct ktermios *tp;
3210 if (driver->flags & TTY_DRIVER_INSTALLED) {
3212 * Free the termios and termios_locked structures because
3213 * we don't want to get memory leaks when modular tty
3214 * drivers are removed from the kernel.
3216 for (i = 0; i < driver->num; i++) {
3217 tp = driver->termios[i];
3219 driver->termios[i] = NULL;
3222 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3223 tty_unregister_device(driver, i);
3225 proc_tty_unregister_driver(driver);
3226 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3227 cdev_del(&driver->cdevs[0]);
3229 kfree(driver->cdevs);
3230 kfree(driver->ports);
3231 kfree(driver->termios);
3232 kfree(driver->ttys);
3236 void tty_driver_kref_put(struct tty_driver *driver)
3238 kref_put(&driver->kref, destruct_tty_driver);
3240 EXPORT_SYMBOL(tty_driver_kref_put);
3242 void tty_set_operations(struct tty_driver *driver,
3243 const struct tty_operations *op)
3247 EXPORT_SYMBOL(tty_set_operations);
3249 void put_tty_driver(struct tty_driver *d)
3251 tty_driver_kref_put(d);
3253 EXPORT_SYMBOL(put_tty_driver);
3256 * Called by a tty driver to register itself.
3258 int tty_register_driver(struct tty_driver *driver)
3265 if (!driver->major) {
3266 error = alloc_chrdev_region(&dev, driver->minor_start,
3267 driver->num, driver->name);
3269 driver->major = MAJOR(dev);
3270 driver->minor_start = MINOR(dev);
3273 dev = MKDEV(driver->major, driver->minor_start);
3274 error = register_chrdev_region(dev, driver->num, driver->name);
3279 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3280 error = tty_cdev_add(driver, dev, 0, driver->num);
3282 goto err_unreg_char;
3285 mutex_lock(&tty_mutex);
3286 list_add(&driver->tty_drivers, &tty_drivers);
3287 mutex_unlock(&tty_mutex);
3289 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3290 for (i = 0; i < driver->num; i++) {
3291 d = tty_register_device(driver, i, NULL);
3294 goto err_unreg_devs;
3298 proc_tty_register_driver(driver);
3299 driver->flags |= TTY_DRIVER_INSTALLED;
3303 for (i--; i >= 0; i--)
3304 tty_unregister_device(driver, i);
3306 mutex_lock(&tty_mutex);
3307 list_del(&driver->tty_drivers);
3308 mutex_unlock(&tty_mutex);
3311 unregister_chrdev_region(dev, driver->num);
3315 EXPORT_SYMBOL(tty_register_driver);
3318 * Called by a tty driver to unregister itself.
3320 int tty_unregister_driver(struct tty_driver *driver)
3324 if (driver->refcount)
3327 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3329 mutex_lock(&tty_mutex);
3330 list_del(&driver->tty_drivers);
3331 mutex_unlock(&tty_mutex);
3335 EXPORT_SYMBOL(tty_unregister_driver);
3337 dev_t tty_devnum(struct tty_struct *tty)
3339 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3341 EXPORT_SYMBOL(tty_devnum);
3343 void proc_clear_tty(struct task_struct *p)
3345 unsigned long flags;
3346 struct tty_struct *tty;
3347 spin_lock_irqsave(&p->sighand->siglock, flags);
3348 tty = p->signal->tty;
3349 p->signal->tty = NULL;
3350 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3354 /* Called under the sighand lock */
3356 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3359 unsigned long flags;
3360 /* We should not have a session or pgrp to put here but.... */
3361 spin_lock_irqsave(&tty->ctrl_lock, flags);
3362 put_pid(tty->session);
3364 tty->pgrp = get_pid(task_pgrp(tsk));
3365 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3366 tty->session = get_pid(task_session(tsk));
3367 if (tsk->signal->tty) {
3368 printk(KERN_DEBUG "tty not NULL!!\n");
3369 tty_kref_put(tsk->signal->tty);
3372 put_pid(tsk->signal->tty_old_pgrp);
3373 tsk->signal->tty = tty_kref_get(tty);
3374 tsk->signal->tty_old_pgrp = NULL;
3377 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3379 spin_lock_irq(&tsk->sighand->siglock);
3380 __proc_set_tty(tsk, tty);
3381 spin_unlock_irq(&tsk->sighand->siglock);
3384 struct tty_struct *get_current_tty(void)
3386 struct tty_struct *tty;
3387 unsigned long flags;
3389 spin_lock_irqsave(¤t->sighand->siglock, flags);
3390 tty = tty_kref_get(current->signal->tty);
3391 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3394 EXPORT_SYMBOL_GPL(get_current_tty);
3396 void tty_default_fops(struct file_operations *fops)
3402 * Initialize the console device. This is called *early*, so
3403 * we can't necessarily depend on lots of kernel help here.
3404 * Just do some early initializations, and do the complex setup
3407 void __init console_init(void)
3411 /* Setup the default TTY line discipline. */
3415 * set up the console device so that later boot sequences can
3416 * inform about problems etc..
3418 call = __con_initcall_start;
3419 while (call < __con_initcall_end) {
3425 static char *tty_devnode(struct device *dev, umode_t *mode)
3429 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3430 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3435 static int __init tty_class_init(void)
3437 tty_class = class_create(THIS_MODULE, "tty");
3438 if (IS_ERR(tty_class))
3439 return PTR_ERR(tty_class);
3440 tty_class->devnode = tty_devnode;
3444 postcore_initcall(tty_class_init);
3446 /* 3/2004 jmc: why do these devices exist? */
3447 static struct cdev tty_cdev, console_cdev;
3449 static ssize_t show_cons_active(struct device *dev,
3450 struct device_attribute *attr, char *buf)
3452 struct console *cs[16];
3458 for_each_console(c) {
3463 if ((c->flags & CON_ENABLED) == 0)
3466 if (i >= ARRAY_SIZE(cs))
3470 count += sprintf(buf + count, "%s%d%c",
3471 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3476 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3478 static struct device *consdev;
3480 void console_sysfs_notify(void)
3483 sysfs_notify(&consdev->kobj, NULL, "active");
3487 * Ok, now we can initialize the rest of the tty devices and can count
3488 * on memory allocations, interrupts etc..
3490 int __init tty_init(void)
3492 cdev_init(&tty_cdev, &tty_fops);
3493 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3494 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3495 panic("Couldn't register /dev/tty driver\n");
3496 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3498 cdev_init(&console_cdev, &console_fops);
3499 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3500 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3501 panic("Couldn't register /dev/console driver\n");
3502 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3504 if (IS_ERR(consdev))
3507 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3510 vty_init(&console_fops);