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->magic = 0xDEADDEAD;
193 static inline struct tty_struct *file_tty(struct file *file)
195 return ((struct tty_file_private *)file->private_data)->tty;
198 int tty_alloc_file(struct file *file)
200 struct tty_file_private *priv;
202 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
206 file->private_data = priv;
211 /* Associate a new file with the tty structure */
212 void tty_add_file(struct tty_struct *tty, struct file *file)
214 struct tty_file_private *priv = file->private_data;
219 spin_lock(&tty_files_lock);
220 list_add(&priv->list, &tty->tty_files);
221 spin_unlock(&tty_files_lock);
225 * tty_free_file - free file->private_data
227 * This shall be used only for fail path handling when tty_add_file was not
230 void tty_free_file(struct file *file)
232 struct tty_file_private *priv = file->private_data;
234 file->private_data = NULL;
238 /* Delete file from its tty */
239 static void tty_del_file(struct file *file)
241 struct tty_file_private *priv = file->private_data;
243 spin_lock(&tty_files_lock);
244 list_del(&priv->list);
245 spin_unlock(&tty_files_lock);
250 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
253 * tty_name - return tty naming
254 * @tty: tty structure
255 * @buf: buffer for output
257 * Convert a tty structure into a name. The name reflects the kernel
258 * naming policy and if udev is in use may not reflect user space
263 char *tty_name(struct tty_struct *tty, char *buf)
265 if (!tty) /* Hmm. NULL pointer. That's fun. */
266 strcpy(buf, "NULL tty");
268 strcpy(buf, tty->name);
272 EXPORT_SYMBOL(tty_name);
274 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
277 #ifdef TTY_PARANOIA_CHECK
280 "null TTY for (%d:%d) in %s\n",
281 imajor(inode), iminor(inode), routine);
284 if (tty->magic != TTY_MAGIC) {
286 "bad magic number for tty struct (%d:%d) in %s\n",
287 imajor(inode), iminor(inode), routine);
294 static int check_tty_count(struct tty_struct *tty, const char *routine)
296 #ifdef CHECK_TTY_COUNT
300 spin_lock(&tty_files_lock);
301 list_for_each(p, &tty->tty_files) {
304 spin_unlock(&tty_files_lock);
305 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
306 tty->driver->subtype == PTY_TYPE_SLAVE &&
307 tty->link && tty->link->count)
309 if (tty->count != count) {
310 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
311 "!= #fd's(%d) in %s\n",
312 tty->name, tty->count, count, routine);
320 * get_tty_driver - find device of a tty
321 * @dev_t: device identifier
322 * @index: returns the index of the tty
324 * This routine returns a tty driver structure, given a device number
325 * and also passes back the index number.
327 * Locking: caller must hold tty_mutex
330 static struct tty_driver *get_tty_driver(dev_t device, int *index)
332 struct tty_driver *p;
334 list_for_each_entry(p, &tty_drivers, tty_drivers) {
335 dev_t base = MKDEV(p->major, p->minor_start);
336 if (device < base || device >= base + p->num)
338 *index = device - base;
339 return tty_driver_kref_get(p);
344 #ifdef CONFIG_CONSOLE_POLL
347 * tty_find_polling_driver - find device of a polled tty
348 * @name: name string to match
349 * @line: pointer to resulting tty line nr
351 * This routine returns a tty driver structure, given a name
352 * and the condition that the tty driver is capable of polled
355 struct tty_driver *tty_find_polling_driver(char *name, int *line)
357 struct tty_driver *p, *res = NULL;
362 for (str = name; *str; str++)
363 if ((*str >= '0' && *str <= '9') || *str == ',')
369 tty_line = simple_strtoul(str, &str, 10);
371 mutex_lock(&tty_mutex);
372 /* Search through the tty devices to look for a match */
373 list_for_each_entry(p, &tty_drivers, tty_drivers) {
374 if (strncmp(name, p->name, len) != 0)
382 if (tty_line >= 0 && tty_line < p->num && p->ops &&
383 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
384 res = tty_driver_kref_get(p);
389 mutex_unlock(&tty_mutex);
393 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
397 * tty_check_change - check for POSIX terminal changes
400 * If we try to write to, or set the state of, a terminal and we're
401 * not in the foreground, send a SIGTTOU. If the signal is blocked or
402 * ignored, go ahead and perform the operation. (POSIX 7.2)
407 int tty_check_change(struct tty_struct *tty)
412 if (current->signal->tty != tty)
415 spin_lock_irqsave(&tty->ctrl_lock, flags);
418 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
421 if (task_pgrp(current) == tty->pgrp)
423 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
424 if (is_ignored(SIGTTOU))
426 if (is_current_pgrp_orphaned()) {
430 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
431 set_thread_flag(TIF_SIGPENDING);
436 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
440 EXPORT_SYMBOL(tty_check_change);
442 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
443 size_t count, loff_t *ppos)
448 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
449 size_t count, loff_t *ppos)
454 /* No kernel lock held - none needed ;) */
455 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
457 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
460 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
463 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
466 static long hung_up_tty_compat_ioctl(struct file *file,
467 unsigned int cmd, unsigned long arg)
469 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
472 static const struct file_operations tty_fops = {
477 .unlocked_ioctl = tty_ioctl,
478 .compat_ioctl = tty_compat_ioctl,
480 .release = tty_release,
481 .fasync = tty_fasync,
484 static const struct file_operations console_fops = {
487 .write = redirected_tty_write,
489 .unlocked_ioctl = tty_ioctl,
490 .compat_ioctl = tty_compat_ioctl,
492 .release = tty_release,
493 .fasync = tty_fasync,
496 static const struct file_operations hung_up_tty_fops = {
498 .read = hung_up_tty_read,
499 .write = hung_up_tty_write,
500 .poll = hung_up_tty_poll,
501 .unlocked_ioctl = hung_up_tty_ioctl,
502 .compat_ioctl = hung_up_tty_compat_ioctl,
503 .release = tty_release,
506 static DEFINE_SPINLOCK(redirect_lock);
507 static struct file *redirect;
510 * tty_wakeup - request more data
513 * Internal and external helper for wakeups of tty. This function
514 * informs the line discipline if present that the driver is ready
515 * to receive more output data.
518 void tty_wakeup(struct tty_struct *tty)
520 struct tty_ldisc *ld;
522 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
523 ld = tty_ldisc_ref(tty);
525 if (ld->ops->write_wakeup)
526 ld->ops->write_wakeup(tty);
530 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
533 EXPORT_SYMBOL_GPL(tty_wakeup);
536 * __tty_hangup - actual handler for hangup events
539 * This can be called by a "kworker" kernel thread. That is process
540 * synchronous but doesn't hold any locks, so we need to make sure we
541 * have the appropriate locks for what we're doing.
543 * The hangup event clears any pending redirections onto the hung up
544 * device. It ensures future writes will error and it does the needed
545 * line discipline hangup and signal delivery. The tty object itself
550 * redirect lock for undoing redirection
551 * file list lock for manipulating list of ttys
552 * tty_ldisc_lock from called functions
553 * termios_mutex resetting termios data
554 * tasklist_lock to walk task list for hangup event
555 * ->siglock to protect ->signal/->sighand
557 static void __tty_hangup(struct tty_struct *tty)
559 struct file *cons_filp = NULL;
560 struct file *filp, *f = NULL;
561 struct task_struct *p;
562 struct tty_file_private *priv;
563 int closecount = 0, n;
571 spin_lock(&redirect_lock);
572 if (redirect && file_tty(redirect) == tty) {
576 spin_unlock(&redirect_lock);
580 /* some functions below drop BTM, so we need this bit */
581 set_bit(TTY_HUPPING, &tty->flags);
583 /* inuse_filps is protected by the single tty lock,
584 this really needs to change if we want to flush the
585 workqueue with the lock held */
586 check_tty_count(tty, "tty_hangup");
588 spin_lock(&tty_files_lock);
589 /* This breaks for file handles being sent over AF_UNIX sockets ? */
590 list_for_each_entry(priv, &tty->tty_files, list) {
592 if (filp->f_op->write == redirected_tty_write)
594 if (filp->f_op->write != tty_write)
597 __tty_fasync(-1, filp, 0); /* can't block */
598 filp->f_op = &hung_up_tty_fops;
600 spin_unlock(&tty_files_lock);
603 * it drops BTM and thus races with reopen
604 * we protect the race by TTY_HUPPING
606 tty_ldisc_hangup(tty);
608 read_lock(&tasklist_lock);
610 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
611 spin_lock_irq(&p->sighand->siglock);
612 if (p->signal->tty == tty) {
613 p->signal->tty = NULL;
614 /* We defer the dereferences outside fo
618 if (!p->signal->leader) {
619 spin_unlock_irq(&p->sighand->siglock);
622 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
623 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
624 put_pid(p->signal->tty_old_pgrp); /* A noop */
625 spin_lock_irqsave(&tty->ctrl_lock, flags);
627 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
628 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
629 spin_unlock_irq(&p->sighand->siglock);
630 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
632 read_unlock(&tasklist_lock);
634 spin_lock_irqsave(&tty->ctrl_lock, flags);
635 clear_bit(TTY_THROTTLED, &tty->flags);
636 clear_bit(TTY_PUSH, &tty->flags);
637 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
638 put_pid(tty->session);
642 tty->ctrl_status = 0;
643 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
645 /* Account for the p->signal references we killed */
650 * If one of the devices matches a console pointer, we
651 * cannot just call hangup() because that will cause
652 * tty->count and state->count to go out of sync.
653 * So we just call close() the right number of times.
657 for (n = 0; n < closecount; n++)
658 tty->ops->close(tty, cons_filp);
659 } else if (tty->ops->hangup)
660 (tty->ops->hangup)(tty);
662 * We don't want to have driver/ldisc interactions beyond
663 * the ones we did here. The driver layer expects no
664 * calls after ->hangup() from the ldisc side. However we
665 * can't yet guarantee all that.
667 set_bit(TTY_HUPPED, &tty->flags);
668 clear_bit(TTY_HUPPING, &tty->flags);
669 tty_ldisc_enable(tty);
677 static void do_tty_hangup(struct work_struct *work)
679 struct tty_struct *tty =
680 container_of(work, struct tty_struct, hangup_work);
686 * tty_hangup - trigger a hangup event
687 * @tty: tty to hangup
689 * A carrier loss (virtual or otherwise) has occurred on this like
690 * schedule a hangup sequence to run after this event.
693 void tty_hangup(struct tty_struct *tty)
695 #ifdef TTY_DEBUG_HANGUP
697 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
699 schedule_work(&tty->hangup_work);
702 EXPORT_SYMBOL(tty_hangup);
705 * tty_vhangup - process vhangup
706 * @tty: tty to hangup
708 * The user has asked via system call for the terminal to be hung up.
709 * We do this synchronously so that when the syscall returns the process
710 * is complete. That guarantee is necessary for security reasons.
713 void tty_vhangup(struct tty_struct *tty)
715 #ifdef TTY_DEBUG_HANGUP
718 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
723 EXPORT_SYMBOL(tty_vhangup);
727 * tty_vhangup_self - process vhangup for own ctty
729 * Perform a vhangup on the current controlling tty
732 void tty_vhangup_self(void)
734 struct tty_struct *tty;
736 tty = get_current_tty();
744 * tty_hung_up_p - was tty hung up
745 * @filp: file pointer of tty
747 * Return true if the tty has been subject to a vhangup or a carrier
751 int tty_hung_up_p(struct file *filp)
753 return (filp->f_op == &hung_up_tty_fops);
756 EXPORT_SYMBOL(tty_hung_up_p);
758 static void session_clear_tty(struct pid *session)
760 struct task_struct *p;
761 do_each_pid_task(session, PIDTYPE_SID, p) {
763 } while_each_pid_task(session, PIDTYPE_SID, p);
767 * disassociate_ctty - disconnect controlling tty
768 * @on_exit: true if exiting so need to "hang up" the session
770 * This function is typically called only by the session leader, when
771 * it wants to disassociate itself from its controlling tty.
773 * It performs the following functions:
774 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
775 * (2) Clears the tty from being controlling the session
776 * (3) Clears the controlling tty for all processes in the
779 * The argument on_exit is set to 1 if called when a process is
780 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
783 * BTM is taken for hysterical raisins, and held when
784 * called from no_tty().
785 * tty_mutex is taken to protect tty
786 * ->siglock is taken to protect ->signal/->sighand
787 * tasklist_lock is taken to walk process list for sessions
788 * ->siglock is taken to protect ->signal/->sighand
791 void disassociate_ctty(int on_exit)
793 struct tty_struct *tty;
795 if (!current->signal->leader)
798 tty = get_current_tty();
800 struct pid *tty_pgrp = get_pid(tty->pgrp);
802 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
807 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
809 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
812 } else if (on_exit) {
813 struct pid *old_pgrp;
814 spin_lock_irq(¤t->sighand->siglock);
815 old_pgrp = current->signal->tty_old_pgrp;
816 current->signal->tty_old_pgrp = NULL;
817 spin_unlock_irq(¤t->sighand->siglock);
819 kill_pgrp(old_pgrp, SIGHUP, on_exit);
820 kill_pgrp(old_pgrp, SIGCONT, on_exit);
826 spin_lock_irq(¤t->sighand->siglock);
827 put_pid(current->signal->tty_old_pgrp);
828 current->signal->tty_old_pgrp = NULL;
829 spin_unlock_irq(¤t->sighand->siglock);
831 tty = get_current_tty();
834 spin_lock_irqsave(&tty->ctrl_lock, flags);
835 put_pid(tty->session);
839 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
842 #ifdef TTY_DEBUG_HANGUP
843 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
848 /* Now clear signal->tty under the lock */
849 read_lock(&tasklist_lock);
850 session_clear_tty(task_session(current));
851 read_unlock(&tasklist_lock);
856 * no_tty - Ensure the current process does not have a controlling tty
860 /* FIXME: Review locking here. The tty_lock never covered any race
861 between a new association and proc_clear_tty but possible we need
862 to protect against this anyway */
863 struct task_struct *tsk = current;
864 disassociate_ctty(0);
870 * stop_tty - propagate flow control
873 * Perform flow control to the driver. For PTY/TTY pairs we
874 * must also propagate the TIOCKPKT status. May be called
875 * on an already stopped device and will not re-call the driver
878 * This functionality is used by both the line disciplines for
879 * halting incoming flow and by the driver. It may therefore be
880 * called from any context, may be under the tty atomic_write_lock
884 * Uses the tty control lock internally
887 void stop_tty(struct tty_struct *tty)
890 spin_lock_irqsave(&tty->ctrl_lock, flags);
892 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
896 if (tty->link && tty->link->packet) {
897 tty->ctrl_status &= ~TIOCPKT_START;
898 tty->ctrl_status |= TIOCPKT_STOP;
899 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
901 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
903 (tty->ops->stop)(tty);
906 EXPORT_SYMBOL(stop_tty);
909 * start_tty - propagate flow control
912 * Start a tty that has been stopped if at all possible. Perform
913 * any necessary wakeups and propagate the TIOCPKT status. If this
914 * is the tty was previous stopped and is being started then the
915 * driver start method is invoked and the line discipline woken.
921 void start_tty(struct tty_struct *tty)
924 spin_lock_irqsave(&tty->ctrl_lock, flags);
925 if (!tty->stopped || tty->flow_stopped) {
926 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
930 if (tty->link && tty->link->packet) {
931 tty->ctrl_status &= ~TIOCPKT_STOP;
932 tty->ctrl_status |= TIOCPKT_START;
933 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
935 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
937 (tty->ops->start)(tty);
938 /* If we have a running line discipline it may need kicking */
942 EXPORT_SYMBOL(start_tty);
945 * tty_read - read method for tty device files
946 * @file: pointer to tty file
948 * @count: size of user buffer
951 * Perform the read system call function on this terminal device. Checks
952 * for hung up devices before calling the line discipline method.
955 * Locks the line discipline internally while needed. Multiple
956 * read calls may be outstanding in parallel.
959 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
963 struct tty_struct *tty = file_tty(file);
964 struct tty_ldisc *ld;
966 if (tty_paranoia_check(tty, file_inode(file), "tty_read"))
968 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
971 /* We want to wait for the line discipline to sort out in this
973 ld = tty_ldisc_ref_wait(tty);
975 i = (ld->ops->read)(tty, file, buf, count);
983 void tty_write_unlock(struct tty_struct *tty)
984 __releases(&tty->atomic_write_lock)
986 mutex_unlock(&tty->atomic_write_lock);
987 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
990 int tty_write_lock(struct tty_struct *tty, int ndelay)
991 __acquires(&tty->atomic_write_lock)
993 if (!mutex_trylock(&tty->atomic_write_lock)) {
996 if (mutex_lock_interruptible(&tty->atomic_write_lock))
1003 * Split writes up in sane blocksizes to avoid
1004 * denial-of-service type attacks
1006 static inline ssize_t do_tty_write(
1007 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
1008 struct tty_struct *tty,
1010 const char __user *buf,
1013 ssize_t ret, written = 0;
1016 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1021 * We chunk up writes into a temporary buffer. This
1022 * simplifies low-level drivers immensely, since they
1023 * don't have locking issues and user mode accesses.
1025 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1028 * The default chunk-size is 2kB, because the NTTY
1029 * layer has problems with bigger chunks. It will
1030 * claim to be able to handle more characters than
1033 * FIXME: This can probably go away now except that 64K chunks
1034 * are too likely to fail unless switched to vmalloc...
1037 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1042 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1043 if (tty->write_cnt < chunk) {
1044 unsigned char *buf_chunk;
1049 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1054 kfree(tty->write_buf);
1055 tty->write_cnt = chunk;
1056 tty->write_buf = buf_chunk;
1059 /* Do the write .. */
1061 size_t size = count;
1065 if (copy_from_user(tty->write_buf, buf, size))
1067 ret = write(tty, file, tty->write_buf, size);
1076 if (signal_pending(current))
1083 tty_write_unlock(tty);
1088 * tty_write_message - write a message to a certain tty, not just the console.
1089 * @tty: the destination tty_struct
1090 * @msg: the message to write
1092 * This is used for messages that need to be redirected to a specific tty.
1093 * We don't put it into the syslog queue right now maybe in the future if
1096 * We must still hold the BTM and test the CLOSING flag for the moment.
1099 void tty_write_message(struct tty_struct *tty, char *msg)
1102 mutex_lock(&tty->atomic_write_lock);
1104 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1106 tty->ops->write(tty, msg, strlen(msg));
1109 tty_write_unlock(tty);
1116 * tty_write - write method for tty device file
1117 * @file: tty file pointer
1118 * @buf: user data to write
1119 * @count: bytes to write
1122 * Write data to a tty device via the line discipline.
1125 * Locks the line discipline as required
1126 * Writes to the tty driver are serialized by the atomic_write_lock
1127 * and are then processed in chunks to the device. The line discipline
1128 * write method will not be invoked in parallel for each device.
1131 static ssize_t tty_write(struct file *file, const char __user *buf,
1132 size_t count, loff_t *ppos)
1134 struct tty_struct *tty = file_tty(file);
1135 struct tty_ldisc *ld;
1138 if (tty_paranoia_check(tty, file_inode(file), "tty_write"))
1140 if (!tty || !tty->ops->write ||
1141 (test_bit(TTY_IO_ERROR, &tty->flags)))
1143 /* Short term debug to catch buggy drivers */
1144 if (tty->ops->write_room == NULL)
1145 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1147 ld = tty_ldisc_ref_wait(tty);
1148 if (!ld->ops->write)
1151 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1152 tty_ldisc_deref(ld);
1156 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1157 size_t count, loff_t *ppos)
1159 struct file *p = NULL;
1161 spin_lock(&redirect_lock);
1163 p = get_file(redirect);
1164 spin_unlock(&redirect_lock);
1168 res = vfs_write(p, buf, count, &p->f_pos);
1172 return tty_write(file, buf, count, ppos);
1175 static char ptychar[] = "pqrstuvwxyzabcde";
1178 * pty_line_name - generate name for a pty
1179 * @driver: the tty driver in use
1180 * @index: the minor number
1181 * @p: output buffer of at least 6 bytes
1183 * Generate a name from a driver reference and write it to the output
1188 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1190 int i = index + driver->name_base;
1191 /* ->name is initialized to "ttyp", but "tty" is expected */
1192 sprintf(p, "%s%c%x",
1193 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1194 ptychar[i >> 4 & 0xf], i & 0xf);
1198 * tty_line_name - generate name for a tty
1199 * @driver: the tty driver in use
1200 * @index: the minor number
1201 * @p: output buffer of at least 7 bytes
1203 * Generate a name from a driver reference and write it to the output
1208 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1210 if (driver->flags & TTY_DRIVER_UNNUMBERED_NODE)
1211 strcpy(p, driver->name);
1213 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1217 * tty_driver_lookup_tty() - find an existing tty, if any
1218 * @driver: the driver for the tty
1219 * @idx: the minor number
1221 * Return the tty, if found or ERR_PTR() otherwise.
1223 * Locking: tty_mutex must be held. If tty is found, the mutex must
1224 * be held until the 'fast-open' is also done. Will change once we
1225 * have refcounting in the driver and per driver locking
1227 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1228 struct inode *inode, int idx)
1230 if (driver->ops->lookup)
1231 return driver->ops->lookup(driver, inode, idx);
1233 return driver->ttys[idx];
1237 * tty_init_termios - helper for termios setup
1238 * @tty: the tty to set up
1240 * Initialise the termios structures for this tty. Thus runs under
1241 * the tty_mutex currently so we can be relaxed about ordering.
1244 int tty_init_termios(struct tty_struct *tty)
1246 struct ktermios *tp;
1247 int idx = tty->index;
1249 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1250 tty->termios = tty->driver->init_termios;
1252 /* Check for lazy saved data */
1253 tp = tty->driver->termios[idx];
1257 tty->termios = tty->driver->init_termios;
1259 /* Compatibility until drivers always set this */
1260 tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);
1261 tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);
1264 EXPORT_SYMBOL_GPL(tty_init_termios);
1266 int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty)
1268 int ret = tty_init_termios(tty);
1272 tty_driver_kref_get(driver);
1274 driver->ttys[tty->index] = tty;
1277 EXPORT_SYMBOL_GPL(tty_standard_install);
1280 * tty_driver_install_tty() - install a tty entry in the driver
1281 * @driver: the driver for the tty
1284 * Install a tty object into the driver tables. The tty->index field
1285 * will be set by the time this is called. This method is responsible
1286 * for ensuring any need additional structures are allocated and
1289 * Locking: tty_mutex for now
1291 static int tty_driver_install_tty(struct tty_driver *driver,
1292 struct tty_struct *tty)
1294 return driver->ops->install ? driver->ops->install(driver, tty) :
1295 tty_standard_install(driver, tty);
1299 * tty_driver_remove_tty() - remove a tty from the driver tables
1300 * @driver: the driver for the tty
1301 * @idx: the minor number
1303 * Remvoe a tty object from the driver tables. The tty->index field
1304 * will be set by the time this is called.
1306 * Locking: tty_mutex for now
1308 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1310 if (driver->ops->remove)
1311 driver->ops->remove(driver, tty);
1313 driver->ttys[tty->index] = NULL;
1317 * tty_reopen() - fast re-open of an open tty
1318 * @tty - the tty to open
1320 * Return 0 on success, -errno on error.
1322 * Locking: tty_mutex must be held from the time the tty was found
1323 * till this open completes.
1325 static int tty_reopen(struct tty_struct *tty)
1327 struct tty_driver *driver = tty->driver;
1329 if (test_bit(TTY_CLOSING, &tty->flags) ||
1330 test_bit(TTY_HUPPING, &tty->flags) ||
1331 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1334 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1335 driver->subtype == PTY_TYPE_MASTER) {
1337 * special case for PTY masters: only one open permitted,
1338 * and the slave side open count is incremented as well.
1347 mutex_lock(&tty->ldisc_mutex);
1348 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1349 mutex_unlock(&tty->ldisc_mutex);
1355 * tty_init_dev - initialise a tty device
1356 * @driver: tty driver we are opening a device on
1357 * @idx: device index
1358 * @ret_tty: returned tty structure
1360 * Prepare a tty device. This may not be a "new" clean device but
1361 * could also be an active device. The pty drivers require special
1362 * handling because of this.
1365 * The function is called under the tty_mutex, which
1366 * protects us from the tty struct or driver itself going away.
1368 * On exit the tty device has the line discipline attached and
1369 * a reference count of 1. If a pair was created for pty/tty use
1370 * and the other was a pty master then it too has a reference count of 1.
1372 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1373 * failed open. The new code protects the open with a mutex, so it's
1374 * really quite straightforward. The mutex locking can probably be
1375 * relaxed for the (most common) case of reopening a tty.
1378 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
1380 struct tty_struct *tty;
1384 * First time open is complex, especially for PTY devices.
1385 * This code guarantees that either everything succeeds and the
1386 * TTY is ready for operation, or else the table slots are vacated
1387 * and the allocated memory released. (Except that the termios
1388 * and locked termios may be retained.)
1391 if (!try_module_get(driver->owner))
1392 return ERR_PTR(-ENODEV);
1394 tty = alloc_tty_struct();
1397 goto err_module_put;
1399 initialize_tty_struct(tty, driver, idx);
1402 retval = tty_driver_install_tty(driver, tty);
1404 goto err_deinit_tty;
1407 tty->port = driver->ports[idx];
1409 WARN_RATELIMIT(!tty->port,
1410 "%s: %s driver does not set tty->port. This will crash the kernel later. Fix the driver!\n",
1411 __func__, tty->driver->name);
1413 tty->port->itty = tty;
1416 * Structures all installed ... call the ldisc open routines.
1417 * If we fail here just call release_tty to clean up. No need
1418 * to decrement the use counts, as release_tty doesn't care.
1420 retval = tty_ldisc_setup(tty, tty->link);
1422 goto err_release_tty;
1423 /* Return the tty locked so that it cannot vanish under the caller */
1428 deinitialize_tty_struct(tty);
1429 free_tty_struct(tty);
1431 module_put(driver->owner);
1432 return ERR_PTR(retval);
1434 /* call the tty release_tty routine to clean out this slot */
1437 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1438 "clearing slot %d\n", idx);
1439 release_tty(tty, idx);
1440 return ERR_PTR(retval);
1443 void tty_free_termios(struct tty_struct *tty)
1445 struct ktermios *tp;
1446 int idx = tty->index;
1448 /* If the port is going to reset then it has no termios to save */
1449 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)
1452 /* Stash the termios data */
1453 tp = tty->driver->termios[idx];
1455 tp = kmalloc(sizeof(struct ktermios), GFP_KERNEL);
1457 pr_warn("tty: no memory to save termios state.\n");
1460 tty->driver->termios[idx] = tp;
1464 EXPORT_SYMBOL(tty_free_termios);
1468 * release_one_tty - release tty structure memory
1469 * @kref: kref of tty we are obliterating
1471 * Releases memory associated with a tty structure, and clears out the
1472 * driver table slots. This function is called when a device is no longer
1473 * in use. It also gets called when setup of a device fails.
1476 * takes the file list lock internally when working on the list
1477 * of ttys that the driver keeps.
1479 * This method gets called from a work queue so that the driver private
1480 * cleanup ops can sleep (needed for USB at least)
1482 static void release_one_tty(struct work_struct *work)
1484 struct tty_struct *tty =
1485 container_of(work, struct tty_struct, hangup_work);
1486 struct tty_driver *driver = tty->driver;
1488 if (tty->ops->cleanup)
1489 tty->ops->cleanup(tty);
1492 tty_driver_kref_put(driver);
1493 module_put(driver->owner);
1495 spin_lock(&tty_files_lock);
1496 list_del_init(&tty->tty_files);
1497 spin_unlock(&tty_files_lock);
1500 put_pid(tty->session);
1501 free_tty_struct(tty);
1504 static void queue_release_one_tty(struct kref *kref)
1506 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1508 /* The hangup queue is now free so we can reuse it rather than
1509 waste a chunk of memory for each port */
1510 INIT_WORK(&tty->hangup_work, release_one_tty);
1511 schedule_work(&tty->hangup_work);
1515 * tty_kref_put - release a tty kref
1518 * Release a reference to a tty device and if need be let the kref
1519 * layer destruct the object for us
1522 void tty_kref_put(struct tty_struct *tty)
1525 kref_put(&tty->kref, queue_release_one_tty);
1527 EXPORT_SYMBOL(tty_kref_put);
1530 * release_tty - release tty structure memory
1532 * Release both @tty and a possible linked partner (think pty pair),
1533 * and decrement the refcount of the backing module.
1537 * takes the file list lock internally when working on the list
1538 * of ttys that the driver keeps.
1541 static void release_tty(struct tty_struct *tty, int idx)
1543 /* This should always be true but check for the moment */
1544 WARN_ON(tty->index != idx);
1545 WARN_ON(!mutex_is_locked(&tty_mutex));
1546 if (tty->ops->shutdown)
1547 tty->ops->shutdown(tty);
1548 tty_free_termios(tty);
1549 tty_driver_remove_tty(tty->driver, tty);
1550 tty->port->itty = NULL;
1553 tty_kref_put(tty->link);
1558 * tty_release_checks - check a tty before real release
1559 * @tty: tty to check
1560 * @o_tty: link of @tty (if any)
1561 * @idx: index of the tty
1563 * Performs some paranoid checking before true release of the @tty.
1564 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1566 static int tty_release_checks(struct tty_struct *tty, struct tty_struct *o_tty,
1569 #ifdef TTY_PARANOIA_CHECK
1570 if (idx < 0 || idx >= tty->driver->num) {
1571 printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
1572 __func__, tty->name);
1576 /* not much to check for devpts */
1577 if (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)
1580 if (tty != tty->driver->ttys[idx]) {
1581 printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
1582 __func__, idx, tty->name);
1585 if (tty->driver->other) {
1586 if (o_tty != tty->driver->other->ttys[idx]) {
1587 printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
1588 __func__, idx, tty->name);
1591 if (o_tty->link != tty) {
1592 printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
1601 * tty_release - vfs callback for close
1602 * @inode: inode of tty
1603 * @filp: file pointer for handle to tty
1605 * Called the last time each file handle is closed that references
1606 * this tty. There may however be several such references.
1609 * Takes bkl. See tty_release_dev
1611 * Even releasing the tty structures is a tricky business.. We have
1612 * to be very careful that the structures are all released at the
1613 * same time, as interrupts might otherwise get the wrong pointers.
1615 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1616 * lead to double frees or releasing memory still in use.
1619 int tty_release(struct inode *inode, struct file *filp)
1621 struct tty_struct *tty = file_tty(filp);
1622 struct tty_struct *o_tty;
1623 int pty_master, tty_closing, o_tty_closing, do_sleep;
1627 if (tty_paranoia_check(tty, inode, __func__))
1631 check_tty_count(tty, __func__);
1633 __tty_fasync(-1, filp, 0);
1636 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1637 tty->driver->subtype == PTY_TYPE_MASTER);
1638 /* Review: parallel close */
1641 if (tty_release_checks(tty, o_tty, idx)) {
1646 #ifdef TTY_DEBUG_HANGUP
1647 printk(KERN_DEBUG "%s: %s (tty count=%d)...\n", __func__,
1648 tty_name(tty, buf), tty->count);
1651 if (tty->ops->close)
1652 tty->ops->close(tty, filp);
1656 * Sanity check: if tty->count is going to zero, there shouldn't be
1657 * any waiters on tty->read_wait or tty->write_wait. We test the
1658 * wait queues and kick everyone out _before_ actually starting to
1659 * close. This ensures that we won't block while releasing the tty
1662 * The test for the o_tty closing is necessary, since the master and
1663 * slave sides may close in any order. If the slave side closes out
1664 * first, its count will be one, since the master side holds an open.
1665 * Thus this test wouldn't be triggered at the time the slave closes,
1668 * Note that it's possible for the tty to be opened again while we're
1669 * flushing out waiters. By recalculating the closing flags before
1670 * each iteration we avoid any problems.
1673 /* Guard against races with tty->count changes elsewhere and
1674 opens on /dev/tty */
1676 mutex_lock(&tty_mutex);
1677 tty_lock_pair(tty, o_tty);
1678 tty_closing = tty->count <= 1;
1679 o_tty_closing = o_tty &&
1680 (o_tty->count <= (pty_master ? 1 : 0));
1684 if (waitqueue_active(&tty->read_wait)) {
1685 wake_up_poll(&tty->read_wait, POLLIN);
1688 if (waitqueue_active(&tty->write_wait)) {
1689 wake_up_poll(&tty->write_wait, POLLOUT);
1693 if (o_tty_closing) {
1694 if (waitqueue_active(&o_tty->read_wait)) {
1695 wake_up_poll(&o_tty->read_wait, POLLIN);
1698 if (waitqueue_active(&o_tty->write_wait)) {
1699 wake_up_poll(&o_tty->write_wait, POLLOUT);
1706 printk(KERN_WARNING "%s: %s: read/write wait queue active!\n",
1707 __func__, tty_name(tty, buf));
1708 tty_unlock_pair(tty, o_tty);
1709 mutex_unlock(&tty_mutex);
1714 * The closing flags are now consistent with the open counts on
1715 * both sides, and we've completed the last operation that could
1716 * block, so it's safe to proceed with closing.
1718 * We must *not* drop the tty_mutex until we ensure that a further
1719 * entry into tty_open can not pick up this tty.
1722 if (--o_tty->count < 0) {
1723 printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
1724 __func__, o_tty->count, tty_name(o_tty, buf));
1728 if (--tty->count < 0) {
1729 printk(KERN_WARNING "%s: bad tty->count (%d) for %s\n",
1730 __func__, tty->count, tty_name(tty, buf));
1735 * We've decremented tty->count, so we need to remove this file
1736 * descriptor off the tty->tty_files list; this serves two
1738 * - check_tty_count sees the correct number of file descriptors
1739 * associated with this tty.
1740 * - do_tty_hangup no longer sees this file descriptor as
1741 * something that needs to be handled for hangups.
1746 * Perform some housekeeping before deciding whether to return.
1748 * Set the TTY_CLOSING flag if this was the last open. In the
1749 * case of a pty we may have to wait around for the other side
1750 * to close, and TTY_CLOSING makes sure we can't be reopened.
1753 set_bit(TTY_CLOSING, &tty->flags);
1755 set_bit(TTY_CLOSING, &o_tty->flags);
1758 * If _either_ side is closing, make sure there aren't any
1759 * processes that still think tty or o_tty is their controlling
1762 if (tty_closing || o_tty_closing) {
1763 read_lock(&tasklist_lock);
1764 session_clear_tty(tty->session);
1766 session_clear_tty(o_tty->session);
1767 read_unlock(&tasklist_lock);
1770 mutex_unlock(&tty_mutex);
1771 tty_unlock_pair(tty, o_tty);
1772 /* At this point the TTY_CLOSING flag should ensure a dead tty
1773 cannot be re-opened by a racing opener */
1775 /* check whether both sides are closing ... */
1776 if (!tty_closing || (o_tty && !o_tty_closing))
1779 #ifdef TTY_DEBUG_HANGUP
1780 printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
1783 * Ask the line discipline code to release its structures
1785 tty_ldisc_release(tty, o_tty);
1787 * The release_tty function takes care of the details of clearing
1788 * the slots and preserving the termios structure. The tty_unlock_pair
1789 * should be safe as we keep a kref while the tty is locked (so the
1790 * unlock never unlocks a freed tty).
1792 mutex_lock(&tty_mutex);
1793 release_tty(tty, idx);
1794 mutex_unlock(&tty_mutex);
1800 * tty_open_current_tty - get tty of current task for open
1801 * @device: device number
1802 * @filp: file pointer to tty
1803 * @return: tty of the current task iff @device is /dev/tty
1805 * We cannot return driver and index like for the other nodes because
1806 * devpts will not work then. It expects inodes to be from devpts FS.
1808 * We need to move to returning a refcounted object from all the lookup
1809 * paths including this one.
1811 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1813 struct tty_struct *tty;
1815 if (device != MKDEV(TTYAUX_MAJOR, 0))
1818 tty = get_current_tty();
1820 return ERR_PTR(-ENXIO);
1822 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1825 /* FIXME: we put a reference and return a TTY! */
1826 /* This is only safe because the caller holds tty_mutex */
1831 * tty_lookup_driver - lookup a tty driver for a given device file
1832 * @device: device number
1833 * @filp: file pointer to tty
1834 * @noctty: set if the device should not become a controlling tty
1835 * @index: index for the device in the @return driver
1836 * @return: driver for this inode (with increased refcount)
1838 * If @return is not erroneous, the caller is responsible to decrement the
1839 * refcount by tty_driver_kref_put.
1841 * Locking: tty_mutex protects get_tty_driver
1843 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1844 int *noctty, int *index)
1846 struct tty_driver *driver;
1850 case MKDEV(TTY_MAJOR, 0): {
1851 extern struct tty_driver *console_driver;
1852 driver = tty_driver_kref_get(console_driver);
1853 *index = fg_console;
1858 case MKDEV(TTYAUX_MAJOR, 1): {
1859 struct tty_driver *console_driver = console_device(index);
1860 if (console_driver) {
1861 driver = tty_driver_kref_get(console_driver);
1863 /* Don't let /dev/console block */
1864 filp->f_flags |= O_NONBLOCK;
1869 return ERR_PTR(-ENODEV);
1872 driver = get_tty_driver(device, index);
1874 return ERR_PTR(-ENODEV);
1881 * tty_open - open a tty device
1882 * @inode: inode of device file
1883 * @filp: file pointer to tty
1885 * tty_open and tty_release keep up the tty count that contains the
1886 * number of opens done on a tty. We cannot use the inode-count, as
1887 * different inodes might point to the same tty.
1889 * Open-counting is needed for pty masters, as well as for keeping
1890 * track of serial lines: DTR is dropped when the last close happens.
1891 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1893 * The termios state of a pty is reset on first open so that
1894 * settings don't persist across reuse.
1896 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1897 * tty->count should protect the rest.
1898 * ->siglock protects ->signal/->sighand
1900 * Note: the tty_unlock/lock cases without a ref are only safe due to
1904 static int tty_open(struct inode *inode, struct file *filp)
1906 struct tty_struct *tty;
1908 struct tty_driver *driver = NULL;
1910 dev_t device = inode->i_rdev;
1911 unsigned saved_flags = filp->f_flags;
1913 nonseekable_open(inode, filp);
1916 retval = tty_alloc_file(filp);
1920 noctty = filp->f_flags & O_NOCTTY;
1924 mutex_lock(&tty_mutex);
1925 /* This is protected by the tty_mutex */
1926 tty = tty_open_current_tty(device, filp);
1928 retval = PTR_ERR(tty);
1931 driver = tty_lookup_driver(device, filp, &noctty, &index);
1932 if (IS_ERR(driver)) {
1933 retval = PTR_ERR(driver);
1937 /* check whether we're reopening an existing tty */
1938 tty = tty_driver_lookup_tty(driver, inode, index);
1940 retval = PTR_ERR(tty);
1947 retval = tty_reopen(tty);
1950 tty = ERR_PTR(retval);
1952 } else /* Returns with the tty_lock held for now */
1953 tty = tty_init_dev(driver, index);
1955 mutex_unlock(&tty_mutex);
1957 tty_driver_kref_put(driver);
1959 retval = PTR_ERR(tty);
1963 tty_add_file(tty, filp);
1965 check_tty_count(tty, __func__);
1966 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1967 tty->driver->subtype == PTY_TYPE_MASTER)
1969 #ifdef TTY_DEBUG_HANGUP
1970 printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
1973 retval = tty->ops->open(tty, filp);
1976 filp->f_flags = saved_flags;
1978 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1979 !capable(CAP_SYS_ADMIN))
1983 #ifdef TTY_DEBUG_HANGUP
1984 printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
1987 tty_unlock(tty); /* need to call tty_release without BTM */
1988 tty_release(inode, filp);
1989 if (retval != -ERESTARTSYS)
1992 if (signal_pending(current))
1997 * Need to reset f_op in case a hangup happened.
1999 if (filp->f_op == &hung_up_tty_fops)
2000 filp->f_op = &tty_fops;
2006 mutex_lock(&tty_mutex);
2008 spin_lock_irq(¤t->sighand->siglock);
2010 current->signal->leader &&
2011 !current->signal->tty &&
2012 tty->session == NULL)
2013 __proc_set_tty(current, tty);
2014 spin_unlock_irq(¤t->sighand->siglock);
2016 mutex_unlock(&tty_mutex);
2019 mutex_unlock(&tty_mutex);
2020 /* after locks to avoid deadlock */
2021 if (!IS_ERR_OR_NULL(driver))
2022 tty_driver_kref_put(driver);
2024 tty_free_file(filp);
2031 * tty_poll - check tty status
2032 * @filp: file being polled
2033 * @wait: poll wait structures to update
2035 * Call the line discipline polling method to obtain the poll
2036 * status of the device.
2038 * Locking: locks called line discipline but ldisc poll method
2039 * may be re-entered freely by other callers.
2042 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2044 struct tty_struct *tty = file_tty(filp);
2045 struct tty_ldisc *ld;
2048 if (tty_paranoia_check(tty, file_inode(filp), "tty_poll"))
2051 ld = tty_ldisc_ref_wait(tty);
2053 ret = (ld->ops->poll)(tty, filp, wait);
2054 tty_ldisc_deref(ld);
2058 static int __tty_fasync(int fd, struct file *filp, int on)
2060 struct tty_struct *tty = file_tty(filp);
2061 unsigned long flags;
2064 if (tty_paranoia_check(tty, file_inode(filp), "tty_fasync"))
2067 retval = fasync_helper(fd, filp, on, &tty->fasync);
2074 if (!waitqueue_active(&tty->read_wait))
2075 tty->minimum_to_wake = 1;
2076 spin_lock_irqsave(&tty->ctrl_lock, flags);
2079 type = PIDTYPE_PGID;
2081 pid = task_pid(current);
2085 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2086 retval = __f_setown(filp, pid, type, 0);
2091 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2092 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2099 static int tty_fasync(int fd, struct file *filp, int on)
2101 struct tty_struct *tty = file_tty(filp);
2105 retval = __tty_fasync(fd, filp, on);
2112 * tiocsti - fake input character
2113 * @tty: tty to fake input into
2114 * @p: pointer to character
2116 * Fake input to a tty device. Does the necessary locking and
2119 * FIXME: does not honour flow control ??
2122 * Called functions take tty_ldisc_lock
2123 * current->signal->tty check is safe without locks
2125 * FIXME: may race normal receive processing
2128 static int tiocsti(struct tty_struct *tty, char __user *p)
2131 struct tty_ldisc *ld;
2133 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2135 if (get_user(ch, p))
2137 tty_audit_tiocsti(tty, ch);
2138 ld = tty_ldisc_ref_wait(tty);
2139 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2140 tty_ldisc_deref(ld);
2145 * tiocgwinsz - implement window query ioctl
2147 * @arg: user buffer for result
2149 * Copies the kernel idea of the window size into the user buffer.
2151 * Locking: tty->termios_mutex is taken to ensure the winsize data
2155 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2159 mutex_lock(&tty->termios_mutex);
2160 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2161 mutex_unlock(&tty->termios_mutex);
2163 return err ? -EFAULT: 0;
2167 * tty_do_resize - resize event
2168 * @tty: tty being resized
2169 * @rows: rows (character)
2170 * @cols: cols (character)
2172 * Update the termios variables and send the necessary signals to
2173 * peform a terminal resize correctly
2176 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2179 unsigned long flags;
2182 mutex_lock(&tty->termios_mutex);
2183 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2185 /* Get the PID values and reference them so we can
2186 avoid holding the tty ctrl lock while sending signals */
2187 spin_lock_irqsave(&tty->ctrl_lock, flags);
2188 pgrp = get_pid(tty->pgrp);
2189 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2192 kill_pgrp(pgrp, SIGWINCH, 1);
2197 mutex_unlock(&tty->termios_mutex);
2200 EXPORT_SYMBOL(tty_do_resize);
2203 * tiocswinsz - implement window size set ioctl
2204 * @tty; tty side of tty
2205 * @arg: user buffer for result
2207 * Copies the user idea of the window size to the kernel. Traditionally
2208 * this is just advisory information but for the Linux console it
2209 * actually has driver level meaning and triggers a VC resize.
2212 * Driver dependent. The default do_resize method takes the
2213 * tty termios mutex and ctrl_lock. The console takes its own lock
2214 * then calls into the default method.
2217 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2219 struct winsize tmp_ws;
2220 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2223 if (tty->ops->resize)
2224 return tty->ops->resize(tty, &tmp_ws);
2226 return tty_do_resize(tty, &tmp_ws);
2230 * tioccons - allow admin to move logical console
2231 * @file: the file to become console
2233 * Allow the administrator to move the redirected console device
2235 * Locking: uses redirect_lock to guard the redirect information
2238 static int tioccons(struct file *file)
2240 if (!capable(CAP_SYS_ADMIN))
2242 if (file->f_op->write == redirected_tty_write) {
2244 spin_lock(&redirect_lock);
2247 spin_unlock(&redirect_lock);
2252 spin_lock(&redirect_lock);
2254 spin_unlock(&redirect_lock);
2257 redirect = get_file(file);
2258 spin_unlock(&redirect_lock);
2263 * fionbio - non blocking ioctl
2264 * @file: file to set blocking value
2265 * @p: user parameter
2267 * Historical tty interfaces had a blocking control ioctl before
2268 * the generic functionality existed. This piece of history is preserved
2269 * in the expected tty API of posix OS's.
2271 * Locking: none, the open file handle ensures it won't go away.
2274 static int fionbio(struct file *file, int __user *p)
2278 if (get_user(nonblock, p))
2281 spin_lock(&file->f_lock);
2283 file->f_flags |= O_NONBLOCK;
2285 file->f_flags &= ~O_NONBLOCK;
2286 spin_unlock(&file->f_lock);
2291 * tiocsctty - set controlling tty
2292 * @tty: tty structure
2293 * @arg: user argument
2295 * This ioctl is used to manage job control. It permits a session
2296 * leader to set this tty as the controlling tty for the session.
2299 * Takes tty_mutex() to protect tty instance
2300 * Takes tasklist_lock internally to walk sessions
2301 * Takes ->siglock() when updating signal->tty
2304 static int tiocsctty(struct tty_struct *tty, int arg)
2307 if (current->signal->leader && (task_session(current) == tty->session))
2310 mutex_lock(&tty_mutex);
2312 * The process must be a session leader and
2313 * not have a controlling tty already.
2315 if (!current->signal->leader || current->signal->tty) {
2322 * This tty is already the controlling
2323 * tty for another session group!
2325 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2329 read_lock(&tasklist_lock);
2330 session_clear_tty(tty->session);
2331 read_unlock(&tasklist_lock);
2337 proc_set_tty(current, tty);
2339 mutex_unlock(&tty_mutex);
2344 * tty_get_pgrp - return a ref counted pgrp pid
2347 * Returns a refcounted instance of the pid struct for the process
2348 * group controlling the tty.
2351 struct pid *tty_get_pgrp(struct tty_struct *tty)
2353 unsigned long flags;
2356 spin_lock_irqsave(&tty->ctrl_lock, flags);
2357 pgrp = get_pid(tty->pgrp);
2358 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2362 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2365 * tiocgpgrp - get process group
2366 * @tty: tty passed by user
2367 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2370 * Obtain the process group of the tty. If there is no process group
2373 * Locking: none. Reference to current->signal->tty is safe.
2376 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2381 * (tty == real_tty) is a cheap way of
2382 * testing if the tty is NOT a master pty.
2384 if (tty == real_tty && current->signal->tty != real_tty)
2386 pid = tty_get_pgrp(real_tty);
2387 ret = put_user(pid_vnr(pid), p);
2393 * tiocspgrp - attempt to set process group
2394 * @tty: tty passed by user
2395 * @real_tty: tty side device matching tty passed by user
2398 * Set the process group of the tty to the session passed. Only
2399 * permitted where the tty session is our session.
2401 * Locking: RCU, ctrl lock
2404 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2408 int retval = tty_check_change(real_tty);
2409 unsigned long flags;
2415 if (!current->signal->tty ||
2416 (current->signal->tty != real_tty) ||
2417 (real_tty->session != task_session(current)))
2419 if (get_user(pgrp_nr, p))
2424 pgrp = find_vpid(pgrp_nr);
2429 if (session_of_pgrp(pgrp) != task_session(current))
2432 spin_lock_irqsave(&tty->ctrl_lock, flags);
2433 put_pid(real_tty->pgrp);
2434 real_tty->pgrp = get_pid(pgrp);
2435 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2442 * tiocgsid - get session id
2443 * @tty: tty passed by user
2444 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2445 * @p: pointer to returned session id
2447 * Obtain the session id of the tty. If there is no session
2450 * Locking: none. Reference to current->signal->tty is safe.
2453 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2456 * (tty == real_tty) is a cheap way of
2457 * testing if the tty is NOT a master pty.
2459 if (tty == real_tty && current->signal->tty != real_tty)
2461 if (!real_tty->session)
2463 return put_user(pid_vnr(real_tty->session), p);
2467 * tiocsetd - set line discipline
2469 * @p: pointer to user data
2471 * Set the line discipline according to user request.
2473 * Locking: see tty_set_ldisc, this function is just a helper
2476 static int tiocsetd(struct tty_struct *tty, int __user *p)
2481 if (get_user(ldisc, p))
2484 ret = tty_set_ldisc(tty, ldisc);
2490 * send_break - performed time break
2491 * @tty: device to break on
2492 * @duration: timeout in mS
2494 * Perform a timed break on hardware that lacks its own driver level
2495 * timed break functionality.
2498 * atomic_write_lock serializes
2502 static int send_break(struct tty_struct *tty, unsigned int duration)
2506 if (tty->ops->break_ctl == NULL)
2509 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2510 retval = tty->ops->break_ctl(tty, duration);
2512 /* Do the work ourselves */
2513 if (tty_write_lock(tty, 0) < 0)
2515 retval = tty->ops->break_ctl(tty, -1);
2518 if (!signal_pending(current))
2519 msleep_interruptible(duration);
2520 retval = tty->ops->break_ctl(tty, 0);
2522 tty_write_unlock(tty);
2523 if (signal_pending(current))
2530 * tty_tiocmget - get modem status
2532 * @file: user file pointer
2533 * @p: pointer to result
2535 * Obtain the modem status bits from the tty driver if the feature
2536 * is supported. Return -EINVAL if it is not available.
2538 * Locking: none (up to the driver)
2541 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2543 int retval = -EINVAL;
2545 if (tty->ops->tiocmget) {
2546 retval = tty->ops->tiocmget(tty);
2549 retval = put_user(retval, p);
2555 * tty_tiocmset - set modem status
2557 * @cmd: command - clear bits, set bits or set all
2558 * @p: pointer to desired bits
2560 * Set the modem status bits from the tty driver if the feature
2561 * is supported. Return -EINVAL if it is not available.
2563 * Locking: none (up to the driver)
2566 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2570 unsigned int set, clear, val;
2572 if (tty->ops->tiocmset == NULL)
2575 retval = get_user(val, p);
2591 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2592 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2593 return tty->ops->tiocmset(tty, set, clear);
2596 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2598 int retval = -EINVAL;
2599 struct serial_icounter_struct icount;
2600 memset(&icount, 0, sizeof(icount));
2601 if (tty->ops->get_icount)
2602 retval = tty->ops->get_icount(tty, &icount);
2605 if (copy_to_user(arg, &icount, sizeof(icount)))
2610 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2612 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2613 tty->driver->subtype == PTY_TYPE_MASTER)
2617 EXPORT_SYMBOL(tty_pair_get_tty);
2619 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2621 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2622 tty->driver->subtype == PTY_TYPE_MASTER)
2626 EXPORT_SYMBOL(tty_pair_get_pty);
2629 * Split this up, as gcc can choke on it otherwise..
2631 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2633 struct tty_struct *tty = file_tty(file);
2634 struct tty_struct *real_tty;
2635 void __user *p = (void __user *)arg;
2637 struct tty_ldisc *ld;
2639 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2642 real_tty = tty_pair_get_tty(tty);
2645 * Factor out some common prep work
2653 retval = tty_check_change(tty);
2656 if (cmd != TIOCCBRK) {
2657 tty_wait_until_sent(tty, 0);
2658 if (signal_pending(current))
2669 return tiocsti(tty, p);
2671 return tiocgwinsz(real_tty, p);
2673 return tiocswinsz(real_tty, p);
2675 return real_tty != tty ? -EINVAL : tioccons(file);
2677 return fionbio(file, p);
2679 set_bit(TTY_EXCLUSIVE, &tty->flags);
2682 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2686 int excl = test_bit(TTY_EXCLUSIVE, &tty->flags);
2687 return put_user(excl, (int __user *)p);
2690 if (current->signal->tty != tty)
2695 return tiocsctty(tty, arg);
2697 return tiocgpgrp(tty, real_tty, p);
2699 return tiocspgrp(tty, real_tty, p);
2701 return tiocgsid(tty, real_tty, p);
2703 return put_user(tty->ldisc->ops->num, (int __user *)p);
2705 return tiocsetd(tty, p);
2707 if (!capable(CAP_SYS_ADMIN))
2713 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2714 return put_user(ret, (unsigned int __user *)p);
2719 case TIOCSBRK: /* Turn break on, unconditionally */
2720 if (tty->ops->break_ctl)
2721 return tty->ops->break_ctl(tty, -1);
2723 case TIOCCBRK: /* Turn break off, unconditionally */
2724 if (tty->ops->break_ctl)
2725 return tty->ops->break_ctl(tty, 0);
2727 case TCSBRK: /* SVID version: non-zero arg --> no break */
2728 /* non-zero arg means wait for all output data
2729 * to be sent (performed above) but don't send break.
2730 * This is used by the tcdrain() termios function.
2733 return send_break(tty, 250);
2735 case TCSBRKP: /* support for POSIX tcsendbreak() */
2736 return send_break(tty, arg ? arg*100 : 250);
2739 return tty_tiocmget(tty, p);
2743 return tty_tiocmset(tty, cmd, p);
2745 retval = tty_tiocgicount(tty, p);
2746 /* For the moment allow fall through to the old method */
2747 if (retval != -EINVAL)
2754 /* flush tty buffer and allow ldisc to process ioctl */
2755 tty_buffer_flush(tty);
2760 if (tty->ops->ioctl) {
2761 retval = (tty->ops->ioctl)(tty, cmd, arg);
2762 if (retval != -ENOIOCTLCMD)
2765 ld = tty_ldisc_ref_wait(tty);
2767 if (ld->ops->ioctl) {
2768 retval = ld->ops->ioctl(tty, file, cmd, arg);
2769 if (retval == -ENOIOCTLCMD)
2772 tty_ldisc_deref(ld);
2776 #ifdef CONFIG_COMPAT
2777 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2780 struct tty_struct *tty = file_tty(file);
2781 struct tty_ldisc *ld;
2782 int retval = -ENOIOCTLCMD;
2784 if (tty_paranoia_check(tty, file_inode(file), "tty_ioctl"))
2787 if (tty->ops->compat_ioctl) {
2788 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2789 if (retval != -ENOIOCTLCMD)
2793 ld = tty_ldisc_ref_wait(tty);
2794 if (ld->ops->compat_ioctl)
2795 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2797 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2798 tty_ldisc_deref(ld);
2804 static int this_tty(const void *t, struct file *file, unsigned fd)
2806 if (likely(file->f_op->read != tty_read))
2808 return file_tty(file) != t ? 0 : fd + 1;
2812 * This implements the "Secure Attention Key" --- the idea is to
2813 * prevent trojan horses by killing all processes associated with this
2814 * tty when the user hits the "Secure Attention Key". Required for
2815 * super-paranoid applications --- see the Orange Book for more details.
2817 * This code could be nicer; ideally it should send a HUP, wait a few
2818 * seconds, then send a INT, and then a KILL signal. But you then
2819 * have to coordinate with the init process, since all processes associated
2820 * with the current tty must be dead before the new getty is allowed
2823 * Now, if it would be correct ;-/ The current code has a nasty hole -
2824 * it doesn't catch files in flight. We may send the descriptor to ourselves
2825 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2827 * Nasty bug: do_SAK is being called in interrupt context. This can
2828 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2830 void __do_SAK(struct tty_struct *tty)
2835 struct task_struct *g, *p;
2836 struct pid *session;
2841 session = tty->session;
2843 tty_ldisc_flush(tty);
2845 tty_driver_flush_buffer(tty);
2847 read_lock(&tasklist_lock);
2848 /* Kill the entire session */
2849 do_each_pid_task(session, PIDTYPE_SID, p) {
2850 printk(KERN_NOTICE "SAK: killed process %d"
2851 " (%s): task_session(p)==tty->session\n",
2852 task_pid_nr(p), p->comm);
2853 send_sig(SIGKILL, p, 1);
2854 } while_each_pid_task(session, PIDTYPE_SID, p);
2855 /* Now kill any processes that happen to have the
2858 do_each_thread(g, p) {
2859 if (p->signal->tty == tty) {
2860 printk(KERN_NOTICE "SAK: killed process %d"
2861 " (%s): task_session(p)==tty->session\n",
2862 task_pid_nr(p), p->comm);
2863 send_sig(SIGKILL, p, 1);
2867 i = iterate_fd(p->files, 0, this_tty, tty);
2869 printk(KERN_NOTICE "SAK: killed process %d"
2870 " (%s): fd#%d opened to the tty\n",
2871 task_pid_nr(p), p->comm, i - 1);
2872 force_sig(SIGKILL, p);
2875 } while_each_thread(g, p);
2876 read_unlock(&tasklist_lock);
2880 static void do_SAK_work(struct work_struct *work)
2882 struct tty_struct *tty =
2883 container_of(work, struct tty_struct, SAK_work);
2888 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2889 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2890 * the values which we write to it will be identical to the values which it
2891 * already has. --akpm
2893 void do_SAK(struct tty_struct *tty)
2897 schedule_work(&tty->SAK_work);
2900 EXPORT_SYMBOL(do_SAK);
2902 static int dev_match_devt(struct device *dev, const void *data)
2904 const dev_t *devt = data;
2905 return dev->devt == *devt;
2908 /* Must put_device() after it's unused! */
2909 static struct device *tty_get_device(struct tty_struct *tty)
2911 dev_t devt = tty_devnum(tty);
2912 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2917 * initialize_tty_struct
2918 * @tty: tty to initialize
2920 * This subroutine initializes a tty structure that has been newly
2923 * Locking: none - tty in question must not be exposed at this point
2926 void initialize_tty_struct(struct tty_struct *tty,
2927 struct tty_driver *driver, int idx)
2929 memset(tty, 0, sizeof(struct tty_struct));
2930 kref_init(&tty->kref);
2931 tty->magic = TTY_MAGIC;
2932 tty_ldisc_init(tty);
2933 tty->session = NULL;
2935 mutex_init(&tty->legacy_mutex);
2936 mutex_init(&tty->termios_mutex);
2937 mutex_init(&tty->ldisc_mutex);
2938 init_waitqueue_head(&tty->write_wait);
2939 init_waitqueue_head(&tty->read_wait);
2940 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2941 mutex_init(&tty->atomic_write_lock);
2942 spin_lock_init(&tty->ctrl_lock);
2943 INIT_LIST_HEAD(&tty->tty_files);
2944 INIT_WORK(&tty->SAK_work, do_SAK_work);
2946 tty->driver = driver;
2947 tty->ops = driver->ops;
2949 tty_line_name(driver, idx, tty->name);
2950 tty->dev = tty_get_device(tty);
2954 * deinitialize_tty_struct
2955 * @tty: tty to deinitialize
2957 * This subroutine deinitializes a tty structure that has been newly
2958 * allocated but tty_release cannot be called on that yet.
2960 * Locking: none - tty in question must not be exposed at this point
2962 void deinitialize_tty_struct(struct tty_struct *tty)
2964 tty_ldisc_deinit(tty);
2968 * tty_put_char - write one character to a tty
2972 * Write one byte to the tty using the provided put_char method
2973 * if present. Returns the number of characters successfully output.
2975 * Note: the specific put_char operation in the driver layer may go
2976 * away soon. Don't call it directly, use this method
2979 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2981 if (tty->ops->put_char)
2982 return tty->ops->put_char(tty, ch);
2983 return tty->ops->write(tty, &ch, 1);
2985 EXPORT_SYMBOL_GPL(tty_put_char);
2987 struct class *tty_class;
2989 static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
2990 unsigned int index, unsigned int count)
2992 /* init here, since reused cdevs cause crashes */
2993 cdev_init(&driver->cdevs[index], &tty_fops);
2994 driver->cdevs[index].owner = driver->owner;
2995 return cdev_add(&driver->cdevs[index], dev, count);
2999 * tty_register_device - register a tty device
3000 * @driver: the tty driver that describes the tty device
3001 * @index: the index in the tty driver for this tty device
3002 * @device: a struct device that is associated with this tty device.
3003 * This field is optional, if there is no known struct device
3004 * for this tty device it can be set to NULL safely.
3006 * Returns a pointer to the struct device for this tty device
3007 * (or ERR_PTR(-EFOO) on error).
3009 * This call is required to be made to register an individual tty device
3010 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3011 * that bit is not set, this function should not be called by a tty
3017 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3018 struct device *device)
3020 return tty_register_device_attr(driver, index, device, NULL, NULL);
3022 EXPORT_SYMBOL(tty_register_device);
3024 static void tty_device_create_release(struct device *dev)
3026 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
3031 * tty_register_device_attr - register a tty device
3032 * @driver: the tty driver that describes the tty device
3033 * @index: the index in the tty driver for this tty device
3034 * @device: a struct device that is associated with this tty device.
3035 * This field is optional, if there is no known struct device
3036 * for this tty device it can be set to NULL safely.
3037 * @drvdata: Driver data to be set to device.
3038 * @attr_grp: Attribute group to be set on device.
3040 * Returns a pointer to the struct device for this tty device
3041 * (or ERR_PTR(-EFOO) on error).
3043 * This call is required to be made to register an individual tty device
3044 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3045 * that bit is not set, this function should not be called by a tty
3050 struct device *tty_register_device_attr(struct tty_driver *driver,
3051 unsigned index, struct device *device,
3053 const struct attribute_group **attr_grp)
3056 dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
3057 struct device *dev = NULL;
3058 int retval = -ENODEV;
3061 if (index >= driver->num) {
3062 printk(KERN_ERR "Attempt to register invalid tty line number "
3064 return ERR_PTR(-EINVAL);
3067 if (driver->type == TTY_DRIVER_TYPE_PTY)
3068 pty_line_name(driver, index, name);
3070 tty_line_name(driver, index, name);
3072 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3073 retval = tty_cdev_add(driver, devt, index, 1);
3079 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
3086 dev->class = tty_class;
3087 dev->parent = device;
3088 dev->release = tty_device_create_release;
3089 dev_set_name(dev, "%s", name);
3090 dev->groups = attr_grp;
3091 dev_set_drvdata(dev, drvdata);
3093 retval = device_register(dev);
3102 cdev_del(&driver->cdevs[index]);
3103 return ERR_PTR(retval);
3105 EXPORT_SYMBOL_GPL(tty_register_device_attr);
3108 * tty_unregister_device - unregister a tty device
3109 * @driver: the tty driver that describes the tty device
3110 * @index: the index in the tty driver for this tty device
3112 * If a tty device is registered with a call to tty_register_device() then
3113 * this function must be called when the tty device is gone.
3118 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3120 device_destroy(tty_class,
3121 MKDEV(driver->major, driver->minor_start) + index);
3122 if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
3123 cdev_del(&driver->cdevs[index]);
3125 EXPORT_SYMBOL(tty_unregister_device);
3128 * __tty_alloc_driver -- allocate tty driver
3129 * @lines: count of lines this driver can handle at most
3130 * @owner: module which is repsonsible for this driver
3131 * @flags: some of TTY_DRIVER_* flags, will be set in driver->flags
3133 * This should not be called directly, some of the provided macros should be
3134 * used instead. Use IS_ERR and friends on @retval.
3136 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner,
3137 unsigned long flags)
3139 struct tty_driver *driver;
3140 unsigned int cdevs = 1;
3143 if (!lines || (flags & TTY_DRIVER_UNNUMBERED_NODE && lines > 1))
3144 return ERR_PTR(-EINVAL);
3146 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3148 return ERR_PTR(-ENOMEM);
3150 kref_init(&driver->kref);
3151 driver->magic = TTY_DRIVER_MAGIC;
3152 driver->num = lines;
3153 driver->owner = owner;
3154 driver->flags = flags;
3156 if (!(flags & TTY_DRIVER_DEVPTS_MEM)) {
3157 driver->ttys = kcalloc(lines, sizeof(*driver->ttys),
3159 driver->termios = kcalloc(lines, sizeof(*driver->termios),
3161 if (!driver->ttys || !driver->termios) {
3167 if (!(flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
3168 driver->ports = kcalloc(lines, sizeof(*driver->ports),
3170 if (!driver->ports) {
3177 driver->cdevs = kcalloc(cdevs, sizeof(*driver->cdevs), GFP_KERNEL);
3178 if (!driver->cdevs) {
3185 kfree(driver->ports);
3186 kfree(driver->ttys);
3187 kfree(driver->termios);
3189 return ERR_PTR(err);
3191 EXPORT_SYMBOL(__tty_alloc_driver);
3193 static void destruct_tty_driver(struct kref *kref)
3195 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3197 struct ktermios *tp;
3199 if (driver->flags & TTY_DRIVER_INSTALLED) {
3201 * Free the termios and termios_locked structures because
3202 * we don't want to get memory leaks when modular tty
3203 * drivers are removed from the kernel.
3205 for (i = 0; i < driver->num; i++) {
3206 tp = driver->termios[i];
3208 driver->termios[i] = NULL;
3211 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3212 tty_unregister_device(driver, i);
3214 proc_tty_unregister_driver(driver);
3215 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
3216 cdev_del(&driver->cdevs[0]);
3218 kfree(driver->cdevs);
3219 kfree(driver->ports);
3220 kfree(driver->termios);
3221 kfree(driver->ttys);
3225 void tty_driver_kref_put(struct tty_driver *driver)
3227 kref_put(&driver->kref, destruct_tty_driver);
3229 EXPORT_SYMBOL(tty_driver_kref_put);
3231 void tty_set_operations(struct tty_driver *driver,
3232 const struct tty_operations *op)
3236 EXPORT_SYMBOL(tty_set_operations);
3238 void put_tty_driver(struct tty_driver *d)
3240 tty_driver_kref_put(d);
3242 EXPORT_SYMBOL(put_tty_driver);
3245 * Called by a tty driver to register itself.
3247 int tty_register_driver(struct tty_driver *driver)
3254 if (!driver->major) {
3255 error = alloc_chrdev_region(&dev, driver->minor_start,
3256 driver->num, driver->name);
3258 driver->major = MAJOR(dev);
3259 driver->minor_start = MINOR(dev);
3262 dev = MKDEV(driver->major, driver->minor_start);
3263 error = register_chrdev_region(dev, driver->num, driver->name);
3268 if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC) {
3269 error = tty_cdev_add(driver, dev, 0, driver->num);
3271 goto err_unreg_char;
3274 mutex_lock(&tty_mutex);
3275 list_add(&driver->tty_drivers, &tty_drivers);
3276 mutex_unlock(&tty_mutex);
3278 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3279 for (i = 0; i < driver->num; i++) {
3280 d = tty_register_device(driver, i, NULL);
3283 goto err_unreg_devs;
3287 proc_tty_register_driver(driver);
3288 driver->flags |= TTY_DRIVER_INSTALLED;
3292 for (i--; i >= 0; i--)
3293 tty_unregister_device(driver, i);
3295 mutex_lock(&tty_mutex);
3296 list_del(&driver->tty_drivers);
3297 mutex_unlock(&tty_mutex);
3300 unregister_chrdev_region(dev, driver->num);
3304 EXPORT_SYMBOL(tty_register_driver);
3307 * Called by a tty driver to unregister itself.
3309 int tty_unregister_driver(struct tty_driver *driver)
3313 if (driver->refcount)
3316 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3318 mutex_lock(&tty_mutex);
3319 list_del(&driver->tty_drivers);
3320 mutex_unlock(&tty_mutex);
3324 EXPORT_SYMBOL(tty_unregister_driver);
3326 dev_t tty_devnum(struct tty_struct *tty)
3328 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3330 EXPORT_SYMBOL(tty_devnum);
3332 void proc_clear_tty(struct task_struct *p)
3334 unsigned long flags;
3335 struct tty_struct *tty;
3336 spin_lock_irqsave(&p->sighand->siglock, flags);
3337 tty = p->signal->tty;
3338 p->signal->tty = NULL;
3339 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3343 /* Called under the sighand lock */
3345 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3348 unsigned long flags;
3349 /* We should not have a session or pgrp to put here but.... */
3350 spin_lock_irqsave(&tty->ctrl_lock, flags);
3351 put_pid(tty->session);
3353 tty->pgrp = get_pid(task_pgrp(tsk));
3354 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3355 tty->session = get_pid(task_session(tsk));
3356 if (tsk->signal->tty) {
3357 printk(KERN_DEBUG "tty not NULL!!\n");
3358 tty_kref_put(tsk->signal->tty);
3361 put_pid(tsk->signal->tty_old_pgrp);
3362 tsk->signal->tty = tty_kref_get(tty);
3363 tsk->signal->tty_old_pgrp = NULL;
3366 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3368 spin_lock_irq(&tsk->sighand->siglock);
3369 __proc_set_tty(tsk, tty);
3370 spin_unlock_irq(&tsk->sighand->siglock);
3373 struct tty_struct *get_current_tty(void)
3375 struct tty_struct *tty;
3376 unsigned long flags;
3378 spin_lock_irqsave(¤t->sighand->siglock, flags);
3379 tty = tty_kref_get(current->signal->tty);
3380 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3383 EXPORT_SYMBOL_GPL(get_current_tty);
3385 void tty_default_fops(struct file_operations *fops)
3391 * Initialize the console device. This is called *early*, so
3392 * we can't necessarily depend on lots of kernel help here.
3393 * Just do some early initializations, and do the complex setup
3396 void __init console_init(void)
3400 /* Setup the default TTY line discipline. */
3404 * set up the console device so that later boot sequences can
3405 * inform about problems etc..
3407 call = __con_initcall_start;
3408 while (call < __con_initcall_end) {
3414 static char *tty_devnode(struct device *dev, umode_t *mode)
3418 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3419 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3424 static int __init tty_class_init(void)
3426 tty_class = class_create(THIS_MODULE, "tty");
3427 if (IS_ERR(tty_class))
3428 return PTR_ERR(tty_class);
3429 tty_class->devnode = tty_devnode;
3433 postcore_initcall(tty_class_init);
3435 /* 3/2004 jmc: why do these devices exist? */
3436 static struct cdev tty_cdev, console_cdev;
3438 static ssize_t show_cons_active(struct device *dev,
3439 struct device_attribute *attr, char *buf)
3441 struct console *cs[16];
3447 for_each_console(c) {
3452 if ((c->flags & CON_ENABLED) == 0)
3455 if (i >= ARRAY_SIZE(cs))
3459 count += sprintf(buf + count, "%s%d%c",
3460 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3465 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3467 static struct device *consdev;
3469 void console_sysfs_notify(void)
3472 sysfs_notify(&consdev->kobj, NULL, "active");
3476 * Ok, now we can initialize the rest of the tty devices and can count
3477 * on memory allocations, interrupts etc..
3479 int __init tty_init(void)
3481 cdev_init(&tty_cdev, &tty_fops);
3482 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3483 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3484 panic("Couldn't register /dev/tty driver\n");
3485 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3487 cdev_init(&console_cdev, &console_fops);
3488 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3489 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3490 panic("Couldn't register /dev/console driver\n");
3491 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3493 if (IS_ERR(consdev))
3496 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3499 vty_init(&console_fops);