2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
100 #include <asm/system.h>
102 #include <linux/kbd_kern.h>
103 #include <linux/vt_kern.h>
104 #include <linux/selection.h>
106 #include <linux/kmod.h>
107 #include <linux/nsproxy.h>
109 #undef TTY_DEBUG_HANGUP
111 #define TTY_PARANOIA_CHECK 1
112 #define CHECK_TTY_COUNT 1
114 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
115 .c_iflag = ICRNL | IXON,
116 .c_oflag = OPOST | ONLCR,
117 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
118 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
119 ECHOCTL | ECHOKE | IEXTEN,
125 EXPORT_SYMBOL(tty_std_termios);
127 /* This list gets poked at by procfs and various bits of boot up code. This
128 could do with some rationalisation such as pulling the tty proc function
131 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
133 /* Mutex to protect creating and releasing a tty. This is shared with
134 vt.c for deeply disgusting hack reasons */
135 DEFINE_MUTEX(tty_mutex);
136 EXPORT_SYMBOL(tty_mutex);
138 /* Spinlock to protect the tty->tty_files list */
139 DEFINE_SPINLOCK(tty_files_lock);
141 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
142 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
143 ssize_t redirected_tty_write(struct file *, const char __user *,
145 static unsigned int tty_poll(struct file *, poll_table *);
146 static int tty_open(struct inode *, struct file *);
147 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
149 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
152 #define tty_compat_ioctl NULL
154 static int __tty_fasync(int fd, struct file *filp, int on);
155 static int tty_fasync(int fd, struct file *filp, int on);
156 static void release_tty(struct tty_struct *tty, int idx);
157 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
158 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
161 * alloc_tty_struct - allocate a tty object
163 * Return a new empty tty structure. The data fields have not
164 * been initialized in any way but has been zeroed
169 struct tty_struct *alloc_tty_struct(void)
171 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
175 * free_tty_struct - free a disused tty
176 * @tty: tty struct to free
178 * Free the write buffers, tty queue and tty memory itself.
180 * Locking: none. Must be called after tty is definitely unused
183 void free_tty_struct(struct tty_struct *tty)
186 put_device(tty->dev);
187 kfree(tty->write_buf);
188 tty_buffer_free_all(tty);
192 static inline struct tty_struct *file_tty(struct file *file)
194 return ((struct tty_file_private *)file->private_data)->tty;
197 int tty_alloc_file(struct file *file)
199 struct tty_file_private *priv;
201 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
205 file->private_data = priv;
210 /* Associate a new file with the tty structure */
211 void tty_add_file(struct tty_struct *tty, struct file *file)
213 struct tty_file_private *priv = file->private_data;
218 spin_lock(&tty_files_lock);
219 list_add(&priv->list, &tty->tty_files);
220 spin_unlock(&tty_files_lock);
224 * tty_free_file - free file->private_data
226 * This shall be used only for fail path handling when tty_add_file was not
229 void tty_free_file(struct file *file)
231 struct tty_file_private *priv = file->private_data;
233 file->private_data = NULL;
237 /* Delete file from its tty */
238 void tty_del_file(struct file *file)
240 struct tty_file_private *priv = file->private_data;
242 spin_lock(&tty_files_lock);
243 list_del(&priv->list);
244 spin_unlock(&tty_files_lock);
249 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
252 * tty_name - return tty naming
253 * @tty: tty structure
254 * @buf: buffer for output
256 * Convert a tty structure into a name. The name reflects the kernel
257 * naming policy and if udev is in use may not reflect user space
262 char *tty_name(struct tty_struct *tty, char *buf)
264 if (!tty) /* Hmm. NULL pointer. That's fun. */
265 strcpy(buf, "NULL tty");
267 strcpy(buf, tty->name);
271 EXPORT_SYMBOL(tty_name);
273 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
276 #ifdef TTY_PARANOIA_CHECK
279 "null TTY for (%d:%d) in %s\n",
280 imajor(inode), iminor(inode), routine);
283 if (tty->magic != TTY_MAGIC) {
285 "bad magic number for tty struct (%d:%d) in %s\n",
286 imajor(inode), iminor(inode), routine);
293 static int check_tty_count(struct tty_struct *tty, const char *routine)
295 #ifdef CHECK_TTY_COUNT
299 spin_lock(&tty_files_lock);
300 list_for_each(p, &tty->tty_files) {
303 spin_unlock(&tty_files_lock);
304 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
305 tty->driver->subtype == PTY_TYPE_SLAVE &&
306 tty->link && tty->link->count)
308 if (tty->count != count) {
309 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
310 "!= #fd's(%d) in %s\n",
311 tty->name, tty->count, count, routine);
319 * get_tty_driver - find device of a tty
320 * @dev_t: device identifier
321 * @index: returns the index of the tty
323 * This routine returns a tty driver structure, given a device number
324 * and also passes back the index number.
326 * Locking: caller must hold tty_mutex
329 static struct tty_driver *get_tty_driver(dev_t device, int *index)
331 struct tty_driver *p;
333 list_for_each_entry(p, &tty_drivers, tty_drivers) {
334 dev_t base = MKDEV(p->major, p->minor_start);
335 if (device < base || device >= base + p->num)
337 *index = device - base;
338 return tty_driver_kref_get(p);
343 #ifdef CONFIG_CONSOLE_POLL
346 * tty_find_polling_driver - find device of a polled tty
347 * @name: name string to match
348 * @line: pointer to resulting tty line nr
350 * This routine returns a tty driver structure, given a name
351 * and the condition that the tty driver is capable of polled
354 struct tty_driver *tty_find_polling_driver(char *name, int *line)
356 struct tty_driver *p, *res = NULL;
361 for (str = name; *str; str++)
362 if ((*str >= '0' && *str <= '9') || *str == ',')
368 tty_line = simple_strtoul(str, &str, 10);
370 mutex_lock(&tty_mutex);
371 /* Search through the tty devices to look for a match */
372 list_for_each_entry(p, &tty_drivers, tty_drivers) {
373 if (strncmp(name, p->name, len) != 0)
381 if (tty_line >= 0 && tty_line < p->num && p->ops &&
382 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
383 res = tty_driver_kref_get(p);
388 mutex_unlock(&tty_mutex);
392 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
396 * tty_check_change - check for POSIX terminal changes
399 * If we try to write to, or set the state of, a terminal and we're
400 * not in the foreground, send a SIGTTOU. If the signal is blocked or
401 * ignored, go ahead and perform the operation. (POSIX 7.2)
406 int tty_check_change(struct tty_struct *tty)
411 if (current->signal->tty != tty)
414 spin_lock_irqsave(&tty->ctrl_lock, flags);
417 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
420 if (task_pgrp(current) == tty->pgrp)
422 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
423 if (is_ignored(SIGTTOU))
425 if (is_current_pgrp_orphaned()) {
429 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
430 set_thread_flag(TIF_SIGPENDING);
435 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
439 EXPORT_SYMBOL(tty_check_change);
441 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
442 size_t count, loff_t *ppos)
447 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
448 size_t count, loff_t *ppos)
453 /* No kernel lock held - none needed ;) */
454 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
456 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
459 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
462 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
465 static long hung_up_tty_compat_ioctl(struct file *file,
466 unsigned int cmd, unsigned long arg)
468 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
471 static const struct file_operations tty_fops = {
476 .unlocked_ioctl = tty_ioctl,
477 .compat_ioctl = tty_compat_ioctl,
479 .release = tty_release,
480 .fasync = tty_fasync,
483 static const struct file_operations console_fops = {
486 .write = redirected_tty_write,
488 .unlocked_ioctl = tty_ioctl,
489 .compat_ioctl = tty_compat_ioctl,
491 .release = tty_release,
492 .fasync = tty_fasync,
495 static const struct file_operations hung_up_tty_fops = {
497 .read = hung_up_tty_read,
498 .write = hung_up_tty_write,
499 .poll = hung_up_tty_poll,
500 .unlocked_ioctl = hung_up_tty_ioctl,
501 .compat_ioctl = hung_up_tty_compat_ioctl,
502 .release = tty_release,
505 static DEFINE_SPINLOCK(redirect_lock);
506 static struct file *redirect;
509 * tty_wakeup - request more data
512 * Internal and external helper for wakeups of tty. This function
513 * informs the line discipline if present that the driver is ready
514 * to receive more output data.
517 void tty_wakeup(struct tty_struct *tty)
519 struct tty_ldisc *ld;
521 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
522 ld = tty_ldisc_ref(tty);
524 if (ld->ops->write_wakeup)
525 ld->ops->write_wakeup(tty);
529 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
532 EXPORT_SYMBOL_GPL(tty_wakeup);
535 * __tty_hangup - actual handler for hangup events
538 * This can be called by the "eventd" kernel thread. That is process
539 * synchronous but doesn't hold any locks, so we need to make sure we
540 * have the appropriate locks for what we're doing.
542 * The hangup event clears any pending redirections onto the hung up
543 * device. It ensures future writes will error and it does the needed
544 * line discipline hangup and signal delivery. The tty object itself
549 * redirect lock for undoing redirection
550 * file list lock for manipulating list of ttys
551 * tty_ldisc_lock from called functions
552 * termios_mutex resetting termios data
553 * tasklist_lock to walk task list for hangup event
554 * ->siglock to protect ->signal/->sighand
556 void __tty_hangup(struct tty_struct *tty)
558 struct file *cons_filp = NULL;
559 struct file *filp, *f = NULL;
560 struct task_struct *p;
561 struct tty_file_private *priv;
562 int closecount = 0, n;
570 spin_lock(&redirect_lock);
571 if (redirect && file_tty(redirect) == tty) {
575 spin_unlock(&redirect_lock);
579 /* some functions below drop BTM, so we need this bit */
580 set_bit(TTY_HUPPING, &tty->flags);
582 /* inuse_filps is protected by the single tty lock,
583 this really needs to change if we want to flush the
584 workqueue with the lock held */
585 check_tty_count(tty, "tty_hangup");
587 spin_lock(&tty_files_lock);
588 /* This breaks for file handles being sent over AF_UNIX sockets ? */
589 list_for_each_entry(priv, &tty->tty_files, list) {
591 if (filp->f_op->write == redirected_tty_write)
593 if (filp->f_op->write != tty_write)
596 __tty_fasync(-1, filp, 0); /* can't block */
597 filp->f_op = &hung_up_tty_fops;
599 spin_unlock(&tty_files_lock);
602 * it drops BTM and thus races with reopen
603 * we protect the race by TTY_HUPPING
605 tty_ldisc_hangup(tty);
607 read_lock(&tasklist_lock);
609 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
610 spin_lock_irq(&p->sighand->siglock);
611 if (p->signal->tty == tty) {
612 p->signal->tty = NULL;
613 /* We defer the dereferences outside fo
617 if (!p->signal->leader) {
618 spin_unlock_irq(&p->sighand->siglock);
621 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
622 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
623 put_pid(p->signal->tty_old_pgrp); /* A noop */
624 spin_lock_irqsave(&tty->ctrl_lock, flags);
626 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
627 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
628 spin_unlock_irq(&p->sighand->siglock);
629 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
631 read_unlock(&tasklist_lock);
633 spin_lock_irqsave(&tty->ctrl_lock, flags);
634 clear_bit(TTY_THROTTLED, &tty->flags);
635 clear_bit(TTY_PUSH, &tty->flags);
636 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
637 put_pid(tty->session);
641 tty->ctrl_status = 0;
642 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
644 /* Account for the p->signal references we killed */
649 * If one of the devices matches a console pointer, we
650 * cannot just call hangup() because that will cause
651 * tty->count and state->count to go out of sync.
652 * So we just call close() the right number of times.
656 for (n = 0; n < closecount; n++)
657 tty->ops->close(tty, cons_filp);
658 } else if (tty->ops->hangup)
659 (tty->ops->hangup)(tty);
661 * We don't want to have driver/ldisc interactions beyond
662 * the ones we did here. The driver layer expects no
663 * calls after ->hangup() from the ldisc side. However we
664 * can't yet guarantee all that.
666 set_bit(TTY_HUPPED, &tty->flags);
667 clear_bit(TTY_HUPPING, &tty->flags);
668 tty_ldisc_enable(tty);
676 static void do_tty_hangup(struct work_struct *work)
678 struct tty_struct *tty =
679 container_of(work, struct tty_struct, hangup_work);
685 * tty_hangup - trigger a hangup event
686 * @tty: tty to hangup
688 * A carrier loss (virtual or otherwise) has occurred on this like
689 * schedule a hangup sequence to run after this event.
692 void tty_hangup(struct tty_struct *tty)
694 #ifdef TTY_DEBUG_HANGUP
696 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
698 schedule_work(&tty->hangup_work);
701 EXPORT_SYMBOL(tty_hangup);
704 * tty_vhangup - process vhangup
705 * @tty: tty to hangup
707 * The user has asked via system call for the terminal to be hung up.
708 * We do this synchronously so that when the syscall returns the process
709 * is complete. That guarantee is necessary for security reasons.
712 void tty_vhangup(struct tty_struct *tty)
714 #ifdef TTY_DEBUG_HANGUP
717 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
722 EXPORT_SYMBOL(tty_vhangup);
726 * tty_vhangup_self - process vhangup for own ctty
728 * Perform a vhangup on the current controlling tty
731 void tty_vhangup_self(void)
733 struct tty_struct *tty;
735 tty = get_current_tty();
743 * tty_hung_up_p - was tty hung up
744 * @filp: file pointer of tty
746 * Return true if the tty has been subject to a vhangup or a carrier
750 int tty_hung_up_p(struct file *filp)
752 return (filp->f_op == &hung_up_tty_fops);
755 EXPORT_SYMBOL(tty_hung_up_p);
757 static void session_clear_tty(struct pid *session)
759 struct task_struct *p;
760 do_each_pid_task(session, PIDTYPE_SID, p) {
762 } while_each_pid_task(session, PIDTYPE_SID, p);
766 * disassociate_ctty - disconnect controlling tty
767 * @on_exit: true if exiting so need to "hang up" the session
769 * This function is typically called only by the session leader, when
770 * it wants to disassociate itself from its controlling tty.
772 * It performs the following functions:
773 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
774 * (2) Clears the tty from being controlling the session
775 * (3) Clears the controlling tty for all processes in the
778 * The argument on_exit is set to 1 if called when a process is
779 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
782 * BTM is taken for hysterical raisins, and held when
783 * called from no_tty().
784 * tty_mutex is taken to protect tty
785 * ->siglock is taken to protect ->signal/->sighand
786 * tasklist_lock is taken to walk process list for sessions
787 * ->siglock is taken to protect ->signal/->sighand
790 void disassociate_ctty(int on_exit)
792 struct tty_struct *tty;
794 if (!current->signal->leader)
797 tty = get_current_tty();
799 struct pid *tty_pgrp = get_pid(tty->pgrp);
801 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
806 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
808 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
811 } else if (on_exit) {
812 struct pid *old_pgrp;
813 spin_lock_irq(¤t->sighand->siglock);
814 old_pgrp = current->signal->tty_old_pgrp;
815 current->signal->tty_old_pgrp = NULL;
816 spin_unlock_irq(¤t->sighand->siglock);
818 kill_pgrp(old_pgrp, SIGHUP, on_exit);
819 kill_pgrp(old_pgrp, SIGCONT, on_exit);
825 spin_lock_irq(¤t->sighand->siglock);
826 put_pid(current->signal->tty_old_pgrp);
827 current->signal->tty_old_pgrp = NULL;
828 spin_unlock_irq(¤t->sighand->siglock);
830 tty = get_current_tty();
833 spin_lock_irqsave(&tty->ctrl_lock, flags);
834 put_pid(tty->session);
838 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
841 #ifdef TTY_DEBUG_HANGUP
842 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
847 /* Now clear signal->tty under the lock */
848 read_lock(&tasklist_lock);
849 session_clear_tty(task_session(current));
850 read_unlock(&tasklist_lock);
855 * no_tty - Ensure the current process does not have a controlling tty
859 struct task_struct *tsk = current;
861 disassociate_ctty(0);
868 * stop_tty - propagate flow control
871 * Perform flow control to the driver. For PTY/TTY pairs we
872 * must also propagate the TIOCKPKT status. May be called
873 * on an already stopped device and will not re-call the driver
876 * This functionality is used by both the line disciplines for
877 * halting incoming flow and by the driver. It may therefore be
878 * called from any context, may be under the tty atomic_write_lock
882 * Uses the tty control lock internally
885 void stop_tty(struct tty_struct *tty)
888 spin_lock_irqsave(&tty->ctrl_lock, flags);
890 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
894 if (tty->link && tty->link->packet) {
895 tty->ctrl_status &= ~TIOCPKT_START;
896 tty->ctrl_status |= TIOCPKT_STOP;
897 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
899 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
901 (tty->ops->stop)(tty);
904 EXPORT_SYMBOL(stop_tty);
907 * start_tty - propagate flow control
910 * Start a tty that has been stopped if at all possible. Perform
911 * any necessary wakeups and propagate the TIOCPKT status. If this
912 * is the tty was previous stopped and is being started then the
913 * driver start method is invoked and the line discipline woken.
919 void start_tty(struct tty_struct *tty)
922 spin_lock_irqsave(&tty->ctrl_lock, flags);
923 if (!tty->stopped || tty->flow_stopped) {
924 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
928 if (tty->link && tty->link->packet) {
929 tty->ctrl_status &= ~TIOCPKT_STOP;
930 tty->ctrl_status |= TIOCPKT_START;
931 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
933 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
935 (tty->ops->start)(tty);
936 /* If we have a running line discipline it may need kicking */
940 EXPORT_SYMBOL(start_tty);
943 * tty_read - read method for tty device files
944 * @file: pointer to tty file
946 * @count: size of user buffer
949 * Perform the read system call function on this terminal device. Checks
950 * for hung up devices before calling the line discipline method.
953 * Locks the line discipline internally while needed. Multiple
954 * read calls may be outstanding in parallel.
957 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
961 struct inode *inode = file->f_path.dentry->d_inode;
962 struct tty_struct *tty = file_tty(file);
963 struct tty_ldisc *ld;
965 if (tty_paranoia_check(tty, inode, "tty_read"))
967 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
970 /* We want to wait for the line discipline to sort out in this
972 ld = tty_ldisc_ref_wait(tty);
974 i = (ld->ops->read)(tty, file, buf, count);
979 inode->i_atime = current_fs_time(inode->i_sb);
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))
1081 struct inode *inode = file->f_path.dentry->d_inode;
1082 inode->i_mtime = current_fs_time(inode->i_sb);
1086 tty_write_unlock(tty);
1091 * tty_write_message - write a message to a certain tty, not just the console.
1092 * @tty: the destination tty_struct
1093 * @msg: the message to write
1095 * This is used for messages that need to be redirected to a specific tty.
1096 * We don't put it into the syslog queue right now maybe in the future if
1099 * We must still hold the BTM and test the CLOSING flag for the moment.
1102 void tty_write_message(struct tty_struct *tty, char *msg)
1105 mutex_lock(&tty->atomic_write_lock);
1107 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1109 tty->ops->write(tty, msg, strlen(msg));
1112 tty_write_unlock(tty);
1119 * tty_write - write method for tty device file
1120 * @file: tty file pointer
1121 * @buf: user data to write
1122 * @count: bytes to write
1125 * Write data to a tty device via the line discipline.
1128 * Locks the line discipline as required
1129 * Writes to the tty driver are serialized by the atomic_write_lock
1130 * and are then processed in chunks to the device. The line discipline
1131 * write method will not be invoked in parallel for each device.
1134 static ssize_t tty_write(struct file *file, const char __user *buf,
1135 size_t count, loff_t *ppos)
1137 struct inode *inode = file->f_path.dentry->d_inode;
1138 struct tty_struct *tty = file_tty(file);
1139 struct tty_ldisc *ld;
1142 if (tty_paranoia_check(tty, inode, "tty_write"))
1144 if (!tty || !tty->ops->write ||
1145 (test_bit(TTY_IO_ERROR, &tty->flags)))
1147 /* Short term debug to catch buggy drivers */
1148 if (tty->ops->write_room == NULL)
1149 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1151 ld = tty_ldisc_ref_wait(tty);
1152 if (!ld->ops->write)
1155 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1156 tty_ldisc_deref(ld);
1160 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1161 size_t count, loff_t *ppos)
1163 struct file *p = NULL;
1165 spin_lock(&redirect_lock);
1170 spin_unlock(&redirect_lock);
1174 res = vfs_write(p, buf, count, &p->f_pos);
1178 return tty_write(file, buf, count, ppos);
1181 static char ptychar[] = "pqrstuvwxyzabcde";
1184 * pty_line_name - generate name for a pty
1185 * @driver: the tty driver in use
1186 * @index: the minor number
1187 * @p: output buffer of at least 6 bytes
1189 * Generate a name from a driver reference and write it to the output
1194 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1196 int i = index + driver->name_base;
1197 /* ->name is initialized to "ttyp", but "tty" is expected */
1198 sprintf(p, "%s%c%x",
1199 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1200 ptychar[i >> 4 & 0xf], i & 0xf);
1204 * tty_line_name - generate name for a tty
1205 * @driver: the tty driver in use
1206 * @index: the minor number
1207 * @p: output buffer of at least 7 bytes
1209 * Generate a name from a driver reference and write it to the output
1214 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1216 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1220 * tty_driver_lookup_tty() - find an existing tty, if any
1221 * @driver: the driver for the tty
1222 * @idx: the minor number
1224 * Return the tty, if found or ERR_PTR() otherwise.
1226 * Locking: tty_mutex must be held. If tty is found, the mutex must
1227 * be held until the 'fast-open' is also done. Will change once we
1228 * have refcounting in the driver and per driver locking
1230 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1231 struct inode *inode, int idx)
1233 struct tty_struct *tty;
1235 if (driver->ops->lookup)
1236 return driver->ops->lookup(driver, inode, idx);
1238 tty = driver->ttys[idx];
1243 * tty_init_termios - helper for termios setup
1244 * @tty: the tty to set up
1246 * Initialise the termios structures for this tty. Thus runs under
1247 * the tty_mutex currently so we can be relaxed about ordering.
1250 int tty_init_termios(struct tty_struct *tty)
1252 struct ktermios *tp;
1253 int idx = tty->index;
1255 tp = tty->driver->termios[idx];
1257 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1260 memcpy(tp, &tty->driver->init_termios,
1261 sizeof(struct ktermios));
1262 tty->driver->termios[idx] = tp;
1265 tty->termios_locked = tp + 1;
1267 /* Compatibility until drivers always set this */
1268 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1269 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1272 EXPORT_SYMBOL_GPL(tty_init_termios);
1275 * tty_driver_install_tty() - install a tty entry in the driver
1276 * @driver: the driver for the tty
1279 * Install a tty object into the driver tables. The tty->index field
1280 * will be set by the time this is called. This method is responsible
1281 * for ensuring any need additional structures are allocated and
1284 * Locking: tty_mutex for now
1286 static int tty_driver_install_tty(struct tty_driver *driver,
1287 struct tty_struct *tty)
1289 int idx = tty->index;
1292 if (driver->ops->install) {
1293 ret = driver->ops->install(driver, tty);
1297 if (tty_init_termios(tty) == 0) {
1298 tty_driver_kref_get(driver);
1300 driver->ttys[idx] = tty;
1307 * tty_driver_remove_tty() - remove a tty from the driver tables
1308 * @driver: the driver for the tty
1309 * @idx: the minor number
1311 * Remvoe a tty object from the driver tables. The tty->index field
1312 * will be set by the time this is called.
1314 * Locking: tty_mutex for now
1316 void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty)
1318 if (driver->ops->remove)
1319 driver->ops->remove(driver, tty);
1321 driver->ttys[tty->index] = NULL;
1325 * tty_reopen() - fast re-open of an open tty
1326 * @tty - the tty to open
1328 * Return 0 on success, -errno on error.
1330 * Locking: tty_mutex must be held from the time the tty was found
1331 * till this open completes.
1333 static int tty_reopen(struct tty_struct *tty)
1335 struct tty_driver *driver = tty->driver;
1337 if (test_bit(TTY_CLOSING, &tty->flags) ||
1338 test_bit(TTY_HUPPING, &tty->flags) ||
1339 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1342 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1343 driver->subtype == PTY_TYPE_MASTER) {
1345 * special case for PTY masters: only one open permitted,
1346 * and the slave side open count is incremented as well.
1354 tty->driver = driver; /* N.B. why do this every time?? */
1356 mutex_lock(&tty->ldisc_mutex);
1357 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1358 mutex_unlock(&tty->ldisc_mutex);
1364 * tty_init_dev - initialise a tty device
1365 * @driver: tty driver we are opening a device on
1366 * @idx: device index
1367 * @ret_tty: returned tty structure
1368 * @first_ok: ok to open a new device (used by ptmx)
1370 * Prepare a tty device. This may not be a "new" clean device but
1371 * could also be an active device. The pty drivers require special
1372 * handling because of this.
1375 * The function is called under the tty_mutex, which
1376 * protects us from the tty struct or driver itself going away.
1378 * On exit the tty device has the line discipline attached and
1379 * a reference count of 1. If a pair was created for pty/tty use
1380 * and the other was a pty master then it too has a reference count of 1.
1382 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1383 * failed open. The new code protects the open with a mutex, so it's
1384 * really quite straightforward. The mutex locking can probably be
1385 * relaxed for the (most common) case of reopening a tty.
1388 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1391 struct tty_struct *tty;
1394 /* Check if pty master is being opened multiple times */
1395 if (driver->subtype == PTY_TYPE_MASTER &&
1396 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1397 return ERR_PTR(-EIO);
1401 * First time open is complex, especially for PTY devices.
1402 * This code guarantees that either everything succeeds and the
1403 * TTY is ready for operation, or else the table slots are vacated
1404 * and the allocated memory released. (Except that the termios
1405 * and locked termios may be retained.)
1408 if (!try_module_get(driver->owner))
1409 return ERR_PTR(-ENODEV);
1411 tty = alloc_tty_struct();
1414 goto err_module_put;
1416 initialize_tty_struct(tty, driver, idx);
1418 retval = tty_driver_install_tty(driver, tty);
1420 goto err_deinit_tty;
1423 * Structures all installed ... call the ldisc open routines.
1424 * If we fail here just call release_tty to clean up. No need
1425 * to decrement the use counts, as release_tty doesn't care.
1427 retval = tty_ldisc_setup(tty, tty->link);
1429 goto err_release_tty;
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 */
1441 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1442 "clearing slot %d\n", idx);
1443 release_tty(tty, idx);
1444 return ERR_PTR(retval);
1447 void tty_free_termios(struct tty_struct *tty)
1449 struct ktermios *tp;
1450 int idx = tty->index;
1451 /* Kill this flag and push into drivers for locking etc */
1452 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1453 /* FIXME: Locking on ->termios array */
1455 tty->driver->termios[idx] = NULL;
1459 EXPORT_SYMBOL(tty_free_termios);
1461 void tty_shutdown(struct tty_struct *tty)
1463 tty_driver_remove_tty(tty->driver, tty);
1464 tty_free_termios(tty);
1466 EXPORT_SYMBOL(tty_shutdown);
1469 * release_one_tty - release tty structure memory
1470 * @kref: kref of tty we are obliterating
1472 * Releases memory associated with a tty structure, and clears out the
1473 * driver table slots. This function is called when a device is no longer
1474 * in use. It also gets called when setup of a device fails.
1477 * tty_mutex - sometimes only
1478 * takes the file list lock internally when working on the list
1479 * of ttys that the driver keeps.
1481 * This method gets called from a work queue so that the driver private
1482 * cleanup ops can sleep (needed for USB at least)
1484 static void release_one_tty(struct work_struct *work)
1486 struct tty_struct *tty =
1487 container_of(work, struct tty_struct, hangup_work);
1488 struct tty_driver *driver = tty->driver;
1490 if (tty->ops->cleanup)
1491 tty->ops->cleanup(tty);
1494 tty_driver_kref_put(driver);
1495 module_put(driver->owner);
1497 spin_lock(&tty_files_lock);
1498 list_del_init(&tty->tty_files);
1499 spin_unlock(&tty_files_lock);
1502 put_pid(tty->session);
1503 free_tty_struct(tty);
1506 static void queue_release_one_tty(struct kref *kref)
1508 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1510 if (tty->ops->shutdown)
1511 tty->ops->shutdown(tty);
1515 /* The hangup queue is now free so we can reuse it rather than
1516 waste a chunk of memory for each port */
1517 INIT_WORK(&tty->hangup_work, release_one_tty);
1518 schedule_work(&tty->hangup_work);
1522 * tty_kref_put - release a tty kref
1525 * Release a reference to a tty device and if need be let the kref
1526 * layer destruct the object for us
1529 void tty_kref_put(struct tty_struct *tty)
1532 kref_put(&tty->kref, queue_release_one_tty);
1534 EXPORT_SYMBOL(tty_kref_put);
1537 * release_tty - release tty structure memory
1539 * Release both @tty and a possible linked partner (think pty pair),
1540 * and decrement the refcount of the backing module.
1543 * tty_mutex - sometimes only
1544 * takes the file list lock internally when working on the list
1545 * of ttys that the driver keeps.
1546 * FIXME: should we require tty_mutex is held here ??
1549 static void release_tty(struct tty_struct *tty, int idx)
1551 /* This should always be true but check for the moment */
1552 WARN_ON(tty->index != idx);
1555 tty_kref_put(tty->link);
1560 * tty_release - vfs callback for close
1561 * @inode: inode of tty
1562 * @filp: file pointer for handle to tty
1564 * Called the last time each file handle is closed that references
1565 * this tty. There may however be several such references.
1568 * Takes bkl. See tty_release_dev
1570 * Even releasing the tty structures is a tricky business.. We have
1571 * to be very careful that the structures are all released at the
1572 * same time, as interrupts might otherwise get the wrong pointers.
1574 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1575 * lead to double frees or releasing memory still in use.
1578 int tty_release(struct inode *inode, struct file *filp)
1580 struct tty_struct *tty = file_tty(filp);
1581 struct tty_struct *o_tty;
1582 int pty_master, tty_closing, o_tty_closing, do_sleep;
1587 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1591 check_tty_count(tty, "tty_release_dev");
1593 __tty_fasync(-1, filp, 0);
1596 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1597 tty->driver->subtype == PTY_TYPE_MASTER);
1598 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1601 #ifdef TTY_PARANOIA_CHECK
1602 if (idx < 0 || idx >= tty->driver->num) {
1603 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1604 "free (%s)\n", tty->name);
1609 if (tty != tty->driver->ttys[idx]) {
1611 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1612 "for (%s)\n", idx, tty->name);
1615 if (tty->termios != tty->driver->termios[idx]) {
1617 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1625 #ifdef TTY_DEBUG_HANGUP
1626 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1627 tty_name(tty, buf), tty->count);
1630 #ifdef TTY_PARANOIA_CHECK
1631 if (tty->driver->other &&
1632 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1633 if (o_tty != tty->driver->other->ttys[idx]) {
1635 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1636 "not o_tty for (%s)\n",
1640 if (o_tty->termios != tty->driver->other->termios[idx]) {
1642 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1643 "not o_termios for (%s)\n",
1647 if (o_tty->link != tty) {
1649 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1654 if (tty->ops->close)
1655 tty->ops->close(tty, filp);
1659 * Sanity check: if tty->count is going to zero, there shouldn't be
1660 * any waiters on tty->read_wait or tty->write_wait. We test the
1661 * wait queues and kick everyone out _before_ actually starting to
1662 * close. This ensures that we won't block while releasing the tty
1665 * The test for the o_tty closing is necessary, since the master and
1666 * slave sides may close in any order. If the slave side closes out
1667 * first, its count will be one, since the master side holds an open.
1668 * Thus this test wouldn't be triggered at the time the slave closes,
1671 * Note that it's possible for the tty to be opened again while we're
1672 * flushing out waiters. By recalculating the closing flags before
1673 * each iteration we avoid any problems.
1676 /* Guard against races with tty->count changes elsewhere and
1677 opens on /dev/tty */
1679 mutex_lock(&tty_mutex);
1681 tty_closing = tty->count <= 1;
1682 o_tty_closing = o_tty &&
1683 (o_tty->count <= (pty_master ? 1 : 0));
1687 if (waitqueue_active(&tty->read_wait)) {
1688 wake_up_poll(&tty->read_wait, POLLIN);
1691 if (waitqueue_active(&tty->write_wait)) {
1692 wake_up_poll(&tty->write_wait, POLLOUT);
1696 if (o_tty_closing) {
1697 if (waitqueue_active(&o_tty->read_wait)) {
1698 wake_up_poll(&o_tty->read_wait, POLLIN);
1701 if (waitqueue_active(&o_tty->write_wait)) {
1702 wake_up_poll(&o_tty->write_wait, POLLOUT);
1709 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1710 "active!\n", tty_name(tty, buf));
1712 mutex_unlock(&tty_mutex);
1717 * The closing flags are now consistent with the open counts on
1718 * both sides, and we've completed the last operation that could
1719 * block, so it's safe to proceed with closing.
1722 if (--o_tty->count < 0) {
1723 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1725 o_tty->count, tty_name(o_tty, buf));
1729 if (--tty->count < 0) {
1730 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1731 tty->count, tty_name(tty, buf));
1736 * We've decremented tty->count, so we need to remove this file
1737 * descriptor off the tty->tty_files list; this serves two
1739 * - check_tty_count sees the correct number of file descriptors
1740 * associated with this tty.
1741 * - do_tty_hangup no longer sees this file descriptor as
1742 * something that needs to be handled for hangups.
1747 * Perform some housekeeping before deciding whether to return.
1749 * Set the TTY_CLOSING flag if this was the last open. In the
1750 * case of a pty we may have to wait around for the other side
1751 * to close, and TTY_CLOSING makes sure we can't be reopened.
1754 set_bit(TTY_CLOSING, &tty->flags);
1756 set_bit(TTY_CLOSING, &o_tty->flags);
1759 * If _either_ side is closing, make sure there aren't any
1760 * processes that still think tty or o_tty is their controlling
1763 if (tty_closing || o_tty_closing) {
1764 read_lock(&tasklist_lock);
1765 session_clear_tty(tty->session);
1767 session_clear_tty(o_tty->session);
1768 read_unlock(&tasklist_lock);
1771 mutex_unlock(&tty_mutex);
1773 /* check whether both sides are closing ... */
1774 if (!tty_closing || (o_tty && !o_tty_closing)) {
1779 #ifdef TTY_DEBUG_HANGUP
1780 printk(KERN_DEBUG "freeing tty structure...");
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.
1790 release_tty(tty, idx);
1792 /* Make this pty number available for reallocation */
1794 devpts_kill_index(inode, idx);
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 static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
1810 struct tty_struct *tty;
1812 if (device != MKDEV(TTYAUX_MAJOR, 0))
1815 tty = get_current_tty();
1817 return ERR_PTR(-ENXIO);
1819 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1822 /* FIXME: we put a reference and return a TTY! */
1827 * tty_lookup_driver - lookup a tty driver for a given device file
1828 * @device: device number
1829 * @filp: file pointer to tty
1830 * @noctty: set if the device should not become a controlling tty
1831 * @index: index for the device in the @return driver
1832 * @return: driver for this inode (with increased refcount)
1834 * If @return is not erroneous, the caller is responsible to decrement the
1835 * refcount by tty_driver_kref_put.
1837 * Locking: tty_mutex protects get_tty_driver
1839 static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
1840 int *noctty, int *index)
1842 struct tty_driver *driver;
1846 case MKDEV(TTY_MAJOR, 0): {
1847 extern struct tty_driver *console_driver;
1848 driver = tty_driver_kref_get(console_driver);
1849 *index = fg_console;
1854 case MKDEV(TTYAUX_MAJOR, 1): {
1855 struct tty_driver *console_driver = console_device(index);
1856 if (console_driver) {
1857 driver = tty_driver_kref_get(console_driver);
1859 /* Don't let /dev/console block */
1860 filp->f_flags |= O_NONBLOCK;
1865 return ERR_PTR(-ENODEV);
1868 driver = get_tty_driver(device, index);
1870 return ERR_PTR(-ENODEV);
1877 * tty_open - open a tty device
1878 * @inode: inode of device file
1879 * @filp: file pointer to tty
1881 * tty_open and tty_release keep up the tty count that contains the
1882 * number of opens done on a tty. We cannot use the inode-count, as
1883 * different inodes might point to the same tty.
1885 * Open-counting is needed for pty masters, as well as for keeping
1886 * track of serial lines: DTR is dropped when the last close happens.
1887 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1889 * The termios state of a pty is reset on first open so that
1890 * settings don't persist across reuse.
1892 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1893 * tty->count should protect the rest.
1894 * ->siglock protects ->signal/->sighand
1897 static int tty_open(struct inode *inode, struct file *filp)
1899 struct tty_struct *tty;
1901 struct tty_driver *driver = NULL;
1903 dev_t device = inode->i_rdev;
1904 unsigned saved_flags = filp->f_flags;
1906 nonseekable_open(inode, filp);
1909 retval = tty_alloc_file(filp);
1913 noctty = filp->f_flags & O_NOCTTY;
1917 mutex_lock(&tty_mutex);
1920 tty = tty_open_current_tty(device, filp);
1922 retval = PTR_ERR(tty);
1925 driver = tty_lookup_driver(device, filp, &noctty, &index);
1926 if (IS_ERR(driver)) {
1927 retval = PTR_ERR(driver);
1931 /* check whether we're reopening an existing tty */
1932 tty = tty_driver_lookup_tty(driver, inode, index);
1934 retval = PTR_ERR(tty);
1940 retval = tty_reopen(tty);
1942 tty = ERR_PTR(retval);
1944 tty = tty_init_dev(driver, index, 0);
1946 mutex_unlock(&tty_mutex);
1948 tty_driver_kref_put(driver);
1951 retval = PTR_ERR(tty);
1955 tty_add_file(tty, filp);
1957 check_tty_count(tty, "tty_open");
1958 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1959 tty->driver->subtype == PTY_TYPE_MASTER)
1961 #ifdef TTY_DEBUG_HANGUP
1962 printk(KERN_DEBUG "opening %s...", tty->name);
1965 retval = tty->ops->open(tty, filp);
1968 filp->f_flags = saved_flags;
1970 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1971 !capable(CAP_SYS_ADMIN))
1975 #ifdef TTY_DEBUG_HANGUP
1976 printk(KERN_DEBUG "error %d in opening %s...", retval,
1979 tty_unlock(); /* need to call tty_release without BTM */
1980 tty_release(inode, filp);
1981 if (retval != -ERESTARTSYS)
1984 if (signal_pending(current))
1989 * Need to reset f_op in case a hangup happened.
1992 if (filp->f_op == &hung_up_tty_fops)
1993 filp->f_op = &tty_fops;
2000 mutex_lock(&tty_mutex);
2002 spin_lock_irq(¤t->sighand->siglock);
2004 current->signal->leader &&
2005 !current->signal->tty &&
2006 tty->session == NULL)
2007 __proc_set_tty(current, tty);
2008 spin_unlock_irq(¤t->sighand->siglock);
2010 mutex_unlock(&tty_mutex);
2014 mutex_unlock(&tty_mutex);
2015 /* after locks to avoid deadlock */
2016 if (!IS_ERR_OR_NULL(driver))
2017 tty_driver_kref_put(driver);
2019 tty_free_file(filp);
2026 * tty_poll - check tty status
2027 * @filp: file being polled
2028 * @wait: poll wait structures to update
2030 * Call the line discipline polling method to obtain the poll
2031 * status of the device.
2033 * Locking: locks called line discipline but ldisc poll method
2034 * may be re-entered freely by other callers.
2037 static unsigned int tty_poll(struct file *filp, poll_table *wait)
2039 struct tty_struct *tty = file_tty(filp);
2040 struct tty_ldisc *ld;
2043 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
2046 ld = tty_ldisc_ref_wait(tty);
2048 ret = (ld->ops->poll)(tty, filp, wait);
2049 tty_ldisc_deref(ld);
2053 static int __tty_fasync(int fd, struct file *filp, int on)
2055 struct tty_struct *tty = file_tty(filp);
2056 unsigned long flags;
2059 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
2062 retval = fasync_helper(fd, filp, on, &tty->fasync);
2069 if (!waitqueue_active(&tty->read_wait))
2070 tty->minimum_to_wake = 1;
2071 spin_lock_irqsave(&tty->ctrl_lock, flags);
2074 type = PIDTYPE_PGID;
2076 pid = task_pid(current);
2080 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2081 retval = __f_setown(filp, pid, type, 0);
2086 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2087 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2094 static int tty_fasync(int fd, struct file *filp, int on)
2098 retval = __tty_fasync(fd, filp, on);
2104 * tiocsti - fake input character
2105 * @tty: tty to fake input into
2106 * @p: pointer to character
2108 * Fake input to a tty device. Does the necessary locking and
2111 * FIXME: does not honour flow control ??
2114 * Called functions take tty_ldisc_lock
2115 * current->signal->tty check is safe without locks
2117 * FIXME: may race normal receive processing
2120 static int tiocsti(struct tty_struct *tty, char __user *p)
2123 struct tty_ldisc *ld;
2125 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2127 if (get_user(ch, p))
2129 tty_audit_tiocsti(tty, ch);
2130 ld = tty_ldisc_ref_wait(tty);
2131 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2132 tty_ldisc_deref(ld);
2137 * tiocgwinsz - implement window query ioctl
2139 * @arg: user buffer for result
2141 * Copies the kernel idea of the window size into the user buffer.
2143 * Locking: tty->termios_mutex is taken to ensure the winsize data
2147 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2151 mutex_lock(&tty->termios_mutex);
2152 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2153 mutex_unlock(&tty->termios_mutex);
2155 return err ? -EFAULT: 0;
2159 * tty_do_resize - resize event
2160 * @tty: tty being resized
2161 * @rows: rows (character)
2162 * @cols: cols (character)
2164 * Update the termios variables and send the necessary signals to
2165 * peform a terminal resize correctly
2168 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2171 unsigned long flags;
2174 mutex_lock(&tty->termios_mutex);
2175 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2177 /* Get the PID values and reference them so we can
2178 avoid holding the tty ctrl lock while sending signals */
2179 spin_lock_irqsave(&tty->ctrl_lock, flags);
2180 pgrp = get_pid(tty->pgrp);
2181 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2184 kill_pgrp(pgrp, SIGWINCH, 1);
2189 mutex_unlock(&tty->termios_mutex);
2194 * tiocswinsz - implement window size set ioctl
2195 * @tty; tty side of tty
2196 * @arg: user buffer for result
2198 * Copies the user idea of the window size to the kernel. Traditionally
2199 * this is just advisory information but for the Linux console it
2200 * actually has driver level meaning and triggers a VC resize.
2203 * Driver dependent. The default do_resize method takes the
2204 * tty termios mutex and ctrl_lock. The console takes its own lock
2205 * then calls into the default method.
2208 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2210 struct winsize tmp_ws;
2211 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2214 if (tty->ops->resize)
2215 return tty->ops->resize(tty, &tmp_ws);
2217 return tty_do_resize(tty, &tmp_ws);
2221 * tioccons - allow admin to move logical console
2222 * @file: the file to become console
2224 * Allow the administrator to move the redirected console device
2226 * Locking: uses redirect_lock to guard the redirect information
2229 static int tioccons(struct file *file)
2231 if (!capable(CAP_SYS_ADMIN))
2233 if (file->f_op->write == redirected_tty_write) {
2235 spin_lock(&redirect_lock);
2238 spin_unlock(&redirect_lock);
2243 spin_lock(&redirect_lock);
2245 spin_unlock(&redirect_lock);
2250 spin_unlock(&redirect_lock);
2255 * fionbio - non blocking ioctl
2256 * @file: file to set blocking value
2257 * @p: user parameter
2259 * Historical tty interfaces had a blocking control ioctl before
2260 * the generic functionality existed. This piece of history is preserved
2261 * in the expected tty API of posix OS's.
2263 * Locking: none, the open file handle ensures it won't go away.
2266 static int fionbio(struct file *file, int __user *p)
2270 if (get_user(nonblock, p))
2273 spin_lock(&file->f_lock);
2275 file->f_flags |= O_NONBLOCK;
2277 file->f_flags &= ~O_NONBLOCK;
2278 spin_unlock(&file->f_lock);
2283 * tiocsctty - set controlling tty
2284 * @tty: tty structure
2285 * @arg: user argument
2287 * This ioctl is used to manage job control. It permits a session
2288 * leader to set this tty as the controlling tty for the session.
2291 * Takes tty_mutex() to protect tty instance
2292 * Takes tasklist_lock internally to walk sessions
2293 * Takes ->siglock() when updating signal->tty
2296 static int tiocsctty(struct tty_struct *tty, int arg)
2299 if (current->signal->leader && (task_session(current) == tty->session))
2302 mutex_lock(&tty_mutex);
2304 * The process must be a session leader and
2305 * not have a controlling tty already.
2307 if (!current->signal->leader || current->signal->tty) {
2314 * This tty is already the controlling
2315 * tty for another session group!
2317 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2321 read_lock(&tasklist_lock);
2322 session_clear_tty(tty->session);
2323 read_unlock(&tasklist_lock);
2329 proc_set_tty(current, tty);
2331 mutex_unlock(&tty_mutex);
2336 * tty_get_pgrp - return a ref counted pgrp pid
2339 * Returns a refcounted instance of the pid struct for the process
2340 * group controlling the tty.
2343 struct pid *tty_get_pgrp(struct tty_struct *tty)
2345 unsigned long flags;
2348 spin_lock_irqsave(&tty->ctrl_lock, flags);
2349 pgrp = get_pid(tty->pgrp);
2350 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2354 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2357 * tiocgpgrp - get process group
2358 * @tty: tty passed by user
2359 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2362 * Obtain the process group of the tty. If there is no process group
2365 * Locking: none. Reference to current->signal->tty is safe.
2368 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2373 * (tty == real_tty) is a cheap way of
2374 * testing if the tty is NOT a master pty.
2376 if (tty == real_tty && current->signal->tty != real_tty)
2378 pid = tty_get_pgrp(real_tty);
2379 ret = put_user(pid_vnr(pid), p);
2385 * tiocspgrp - attempt to set process group
2386 * @tty: tty passed by user
2387 * @real_tty: tty side device matching tty passed by user
2390 * Set the process group of the tty to the session passed. Only
2391 * permitted where the tty session is our session.
2393 * Locking: RCU, ctrl lock
2396 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2400 int retval = tty_check_change(real_tty);
2401 unsigned long flags;
2407 if (!current->signal->tty ||
2408 (current->signal->tty != real_tty) ||
2409 (real_tty->session != task_session(current)))
2411 if (get_user(pgrp_nr, p))
2416 pgrp = find_vpid(pgrp_nr);
2421 if (session_of_pgrp(pgrp) != task_session(current))
2424 spin_lock_irqsave(&tty->ctrl_lock, flags);
2425 put_pid(real_tty->pgrp);
2426 real_tty->pgrp = get_pid(pgrp);
2427 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2434 * tiocgsid - get session id
2435 * @tty: tty passed by user
2436 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2437 * @p: pointer to returned session id
2439 * Obtain the session id of the tty. If there is no session
2442 * Locking: none. Reference to current->signal->tty is safe.
2445 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2448 * (tty == real_tty) is a cheap way of
2449 * testing if the tty is NOT a master pty.
2451 if (tty == real_tty && current->signal->tty != real_tty)
2453 if (!real_tty->session)
2455 return put_user(pid_vnr(real_tty->session), p);
2459 * tiocsetd - set line discipline
2461 * @p: pointer to user data
2463 * Set the line discipline according to user request.
2465 * Locking: see tty_set_ldisc, this function is just a helper
2468 static int tiocsetd(struct tty_struct *tty, int __user *p)
2473 if (get_user(ldisc, p))
2476 ret = tty_set_ldisc(tty, ldisc);
2482 * send_break - performed time break
2483 * @tty: device to break on
2484 * @duration: timeout in mS
2486 * Perform a timed break on hardware that lacks its own driver level
2487 * timed break functionality.
2490 * atomic_write_lock serializes
2494 static int send_break(struct tty_struct *tty, unsigned int duration)
2498 if (tty->ops->break_ctl == NULL)
2501 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2502 retval = tty->ops->break_ctl(tty, duration);
2504 /* Do the work ourselves */
2505 if (tty_write_lock(tty, 0) < 0)
2507 retval = tty->ops->break_ctl(tty, -1);
2510 if (!signal_pending(current))
2511 msleep_interruptible(duration);
2512 retval = tty->ops->break_ctl(tty, 0);
2514 tty_write_unlock(tty);
2515 if (signal_pending(current))
2522 * tty_tiocmget - get modem status
2524 * @file: user file pointer
2525 * @p: pointer to result
2527 * Obtain the modem status bits from the tty driver if the feature
2528 * is supported. Return -EINVAL if it is not available.
2530 * Locking: none (up to the driver)
2533 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2535 int retval = -EINVAL;
2537 if (tty->ops->tiocmget) {
2538 retval = tty->ops->tiocmget(tty);
2541 retval = put_user(retval, p);
2547 * tty_tiocmset - set modem status
2549 * @cmd: command - clear bits, set bits or set all
2550 * @p: pointer to desired bits
2552 * Set the modem status bits from the tty driver if the feature
2553 * is supported. Return -EINVAL if it is not available.
2555 * Locking: none (up to the driver)
2558 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2562 unsigned int set, clear, val;
2564 if (tty->ops->tiocmset == NULL)
2567 retval = get_user(val, p);
2583 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2584 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2585 return tty->ops->tiocmset(tty, set, clear);
2588 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2590 int retval = -EINVAL;
2591 struct serial_icounter_struct icount;
2592 memset(&icount, 0, sizeof(icount));
2593 if (tty->ops->get_icount)
2594 retval = tty->ops->get_icount(tty, &icount);
2597 if (copy_to_user(arg, &icount, sizeof(icount)))
2602 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2604 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2605 tty->driver->subtype == PTY_TYPE_MASTER)
2609 EXPORT_SYMBOL(tty_pair_get_tty);
2611 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2613 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2614 tty->driver->subtype == PTY_TYPE_MASTER)
2618 EXPORT_SYMBOL(tty_pair_get_pty);
2621 * Split this up, as gcc can choke on it otherwise..
2623 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2625 struct tty_struct *tty = file_tty(file);
2626 struct tty_struct *real_tty;
2627 void __user *p = (void __user *)arg;
2629 struct tty_ldisc *ld;
2630 struct inode *inode = file->f_dentry->d_inode;
2632 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2635 real_tty = tty_pair_get_tty(tty);
2638 * Factor out some common prep work
2646 retval = tty_check_change(tty);
2649 if (cmd != TIOCCBRK) {
2650 tty_wait_until_sent(tty, 0);
2651 if (signal_pending(current))
2662 return tiocsti(tty, p);
2664 return tiocgwinsz(real_tty, p);
2666 return tiocswinsz(real_tty, p);
2668 return real_tty != tty ? -EINVAL : tioccons(file);
2670 return fionbio(file, p);
2672 set_bit(TTY_EXCLUSIVE, &tty->flags);
2675 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2678 if (current->signal->tty != tty)
2683 return tiocsctty(tty, arg);
2685 return tiocgpgrp(tty, real_tty, p);
2687 return tiocspgrp(tty, real_tty, p);
2689 return tiocgsid(tty, real_tty, p);
2691 return put_user(tty->ldisc->ops->num, (int __user *)p);
2693 return tiocsetd(tty, p);
2695 if (!capable(CAP_SYS_ADMIN))
2701 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2702 return put_user(ret, (unsigned int __user *)p);
2707 case TIOCSBRK: /* Turn break on, unconditionally */
2708 if (tty->ops->break_ctl)
2709 return tty->ops->break_ctl(tty, -1);
2711 case TIOCCBRK: /* Turn break off, unconditionally */
2712 if (tty->ops->break_ctl)
2713 return tty->ops->break_ctl(tty, 0);
2715 case TCSBRK: /* SVID version: non-zero arg --> no break */
2716 /* non-zero arg means wait for all output data
2717 * to be sent (performed above) but don't send break.
2718 * This is used by the tcdrain() termios function.
2721 return send_break(tty, 250);
2723 case TCSBRKP: /* support for POSIX tcsendbreak() */
2724 return send_break(tty, arg ? arg*100 : 250);
2727 return tty_tiocmget(tty, p);
2731 return tty_tiocmset(tty, cmd, p);
2733 retval = tty_tiocgicount(tty, p);
2734 /* For the moment allow fall through to the old method */
2735 if (retval != -EINVAL)
2742 /* flush tty buffer and allow ldisc to process ioctl */
2743 tty_buffer_flush(tty);
2748 if (tty->ops->ioctl) {
2749 retval = (tty->ops->ioctl)(tty, cmd, arg);
2750 if (retval != -ENOIOCTLCMD)
2753 ld = tty_ldisc_ref_wait(tty);
2755 if (ld->ops->ioctl) {
2756 retval = ld->ops->ioctl(tty, file, cmd, arg);
2757 if (retval == -ENOIOCTLCMD)
2760 tty_ldisc_deref(ld);
2764 #ifdef CONFIG_COMPAT
2765 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2768 struct inode *inode = file->f_dentry->d_inode;
2769 struct tty_struct *tty = file_tty(file);
2770 struct tty_ldisc *ld;
2771 int retval = -ENOIOCTLCMD;
2773 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2776 if (tty->ops->compat_ioctl) {
2777 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2778 if (retval != -ENOIOCTLCMD)
2782 ld = tty_ldisc_ref_wait(tty);
2783 if (ld->ops->compat_ioctl)
2784 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2786 retval = n_tty_compat_ioctl_helper(tty, file, cmd, arg);
2787 tty_ldisc_deref(ld);
2794 * This implements the "Secure Attention Key" --- the idea is to
2795 * prevent trojan horses by killing all processes associated with this
2796 * tty when the user hits the "Secure Attention Key". Required for
2797 * super-paranoid applications --- see the Orange Book for more details.
2799 * This code could be nicer; ideally it should send a HUP, wait a few
2800 * seconds, then send a INT, and then a KILL signal. But you then
2801 * have to coordinate with the init process, since all processes associated
2802 * with the current tty must be dead before the new getty is allowed
2805 * Now, if it would be correct ;-/ The current code has a nasty hole -
2806 * it doesn't catch files in flight. We may send the descriptor to ourselves
2807 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2809 * Nasty bug: do_SAK is being called in interrupt context. This can
2810 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2812 void __do_SAK(struct tty_struct *tty)
2817 struct task_struct *g, *p;
2818 struct pid *session;
2821 struct fdtable *fdt;
2825 session = tty->session;
2827 tty_ldisc_flush(tty);
2829 tty_driver_flush_buffer(tty);
2831 read_lock(&tasklist_lock);
2832 /* Kill the entire session */
2833 do_each_pid_task(session, PIDTYPE_SID, p) {
2834 printk(KERN_NOTICE "SAK: killed process %d"
2835 " (%s): task_session(p)==tty->session\n",
2836 task_pid_nr(p), p->comm);
2837 send_sig(SIGKILL, p, 1);
2838 } while_each_pid_task(session, PIDTYPE_SID, p);
2839 /* Now kill any processes that happen to have the
2842 do_each_thread(g, p) {
2843 if (p->signal->tty == tty) {
2844 printk(KERN_NOTICE "SAK: killed process %d"
2845 " (%s): task_session(p)==tty->session\n",
2846 task_pid_nr(p), p->comm);
2847 send_sig(SIGKILL, p, 1);
2853 * We don't take a ref to the file, so we must
2854 * hold ->file_lock instead.
2856 spin_lock(&p->files->file_lock);
2857 fdt = files_fdtable(p->files);
2858 for (i = 0; i < fdt->max_fds; i++) {
2859 filp = fcheck_files(p->files, i);
2862 if (filp->f_op->read == tty_read &&
2863 file_tty(filp) == tty) {
2864 printk(KERN_NOTICE "SAK: killed process %d"
2865 " (%s): fd#%d opened to the tty\n",
2866 task_pid_nr(p), p->comm, i);
2867 force_sig(SIGKILL, p);
2871 spin_unlock(&p->files->file_lock);
2874 } while_each_thread(g, p);
2875 read_unlock(&tasklist_lock);
2879 static void do_SAK_work(struct work_struct *work)
2881 struct tty_struct *tty =
2882 container_of(work, struct tty_struct, SAK_work);
2887 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2888 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2889 * the values which we write to it will be identical to the values which it
2890 * already has. --akpm
2892 void do_SAK(struct tty_struct *tty)
2896 schedule_work(&tty->SAK_work);
2899 EXPORT_SYMBOL(do_SAK);
2901 static int dev_match_devt(struct device *dev, void *data)
2904 return dev->devt == *devt;
2907 /* Must put_device() after it's unused! */
2908 static struct device *tty_get_device(struct tty_struct *tty)
2910 dev_t devt = tty_devnum(tty);
2911 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2916 * initialize_tty_struct
2917 * @tty: tty to initialize
2919 * This subroutine initializes a tty structure that has been newly
2922 * Locking: none - tty in question must not be exposed at this point
2925 void initialize_tty_struct(struct tty_struct *tty,
2926 struct tty_driver *driver, int idx)
2928 memset(tty, 0, sizeof(struct tty_struct));
2929 kref_init(&tty->kref);
2930 tty->magic = TTY_MAGIC;
2931 tty_ldisc_init(tty);
2932 tty->session = NULL;
2934 tty->overrun_time = jiffies;
2935 tty->buf.head = tty->buf.tail = NULL;
2936 tty_buffer_init(tty);
2937 mutex_init(&tty->termios_mutex);
2938 mutex_init(&tty->ldisc_mutex);
2939 init_waitqueue_head(&tty->write_wait);
2940 init_waitqueue_head(&tty->read_wait);
2941 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2942 mutex_init(&tty->atomic_read_lock);
2943 mutex_init(&tty->atomic_write_lock);
2944 mutex_init(&tty->output_lock);
2945 mutex_init(&tty->echo_lock);
2946 spin_lock_init(&tty->read_lock);
2947 spin_lock_init(&tty->ctrl_lock);
2948 INIT_LIST_HEAD(&tty->tty_files);
2949 INIT_WORK(&tty->SAK_work, do_SAK_work);
2951 tty->driver = driver;
2952 tty->ops = driver->ops;
2954 tty_line_name(driver, idx, tty->name);
2955 tty->dev = tty_get_device(tty);
2959 * deinitialize_tty_struct
2960 * @tty: tty to deinitialize
2962 * This subroutine deinitializes a tty structure that has been newly
2963 * allocated but tty_release cannot be called on that yet.
2965 * Locking: none - tty in question must not be exposed at this point
2967 void deinitialize_tty_struct(struct tty_struct *tty)
2969 tty_ldisc_deinit(tty);
2973 * tty_put_char - write one character to a tty
2977 * Write one byte to the tty using the provided put_char method
2978 * if present. Returns the number of characters successfully output.
2980 * Note: the specific put_char operation in the driver layer may go
2981 * away soon. Don't call it directly, use this method
2984 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2986 if (tty->ops->put_char)
2987 return tty->ops->put_char(tty, ch);
2988 return tty->ops->write(tty, &ch, 1);
2990 EXPORT_SYMBOL_GPL(tty_put_char);
2992 struct class *tty_class;
2995 * tty_register_device - register a tty device
2996 * @driver: the tty driver that describes the tty device
2997 * @index: the index in the tty driver for this tty device
2998 * @device: a struct device that is associated with this tty device.
2999 * This field is optional, if there is no known struct device
3000 * for this tty device it can be set to NULL safely.
3002 * Returns a pointer to the struct device for this tty device
3003 * (or ERR_PTR(-EFOO) on error).
3005 * This call is required to be made to register an individual tty device
3006 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3007 * that bit is not set, this function should not be called by a tty
3013 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
3014 struct device *device)
3017 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
3019 if (index >= driver->num) {
3020 printk(KERN_ERR "Attempt to register invalid tty line number "
3022 return ERR_PTR(-EINVAL);
3025 if (driver->type == TTY_DRIVER_TYPE_PTY)
3026 pty_line_name(driver, index, name);
3028 tty_line_name(driver, index, name);
3030 return device_create(tty_class, device, dev, NULL, name);
3032 EXPORT_SYMBOL(tty_register_device);
3035 * tty_unregister_device - unregister a tty device
3036 * @driver: the tty driver that describes the tty device
3037 * @index: the index in the tty driver for this tty device
3039 * If a tty device is registered with a call to tty_register_device() then
3040 * this function must be called when the tty device is gone.
3045 void tty_unregister_device(struct tty_driver *driver, unsigned index)
3047 device_destroy(tty_class,
3048 MKDEV(driver->major, driver->minor_start) + index);
3050 EXPORT_SYMBOL(tty_unregister_device);
3052 struct tty_driver *alloc_tty_driver(int lines)
3054 struct tty_driver *driver;
3056 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
3058 kref_init(&driver->kref);
3059 driver->magic = TTY_DRIVER_MAGIC;
3060 driver->num = lines;
3061 /* later we'll move allocation of tables here */
3065 EXPORT_SYMBOL(alloc_tty_driver);
3067 static void destruct_tty_driver(struct kref *kref)
3069 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3071 struct ktermios *tp;
3074 if (driver->flags & TTY_DRIVER_INSTALLED) {
3076 * Free the termios and termios_locked structures because
3077 * we don't want to get memory leaks when modular tty
3078 * drivers are removed from the kernel.
3080 for (i = 0; i < driver->num; i++) {
3081 tp = driver->termios[i];
3083 driver->termios[i] = NULL;
3086 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3087 tty_unregister_device(driver, i);
3090 proc_tty_unregister_driver(driver);
3091 driver->ttys = NULL;
3092 driver->termios = NULL;
3094 cdev_del(&driver->cdev);
3099 void tty_driver_kref_put(struct tty_driver *driver)
3101 kref_put(&driver->kref, destruct_tty_driver);
3103 EXPORT_SYMBOL(tty_driver_kref_put);
3105 void tty_set_operations(struct tty_driver *driver,
3106 const struct tty_operations *op)
3110 EXPORT_SYMBOL(tty_set_operations);
3112 void put_tty_driver(struct tty_driver *d)
3114 tty_driver_kref_put(d);
3116 EXPORT_SYMBOL(put_tty_driver);
3119 * Called by a tty driver to register itself.
3121 int tty_register_driver(struct tty_driver *driver)
3129 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3130 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3135 if (!driver->major) {
3136 error = alloc_chrdev_region(&dev, driver->minor_start,
3137 driver->num, driver->name);
3139 driver->major = MAJOR(dev);
3140 driver->minor_start = MINOR(dev);
3143 dev = MKDEV(driver->major, driver->minor_start);
3144 error = register_chrdev_region(dev, driver->num, driver->name);
3152 driver->ttys = (struct tty_struct **)p;
3153 driver->termios = (struct ktermios **)(p + driver->num);
3155 driver->ttys = NULL;
3156 driver->termios = NULL;
3159 cdev_init(&driver->cdev, &tty_fops);
3160 driver->cdev.owner = driver->owner;
3161 error = cdev_add(&driver->cdev, dev, driver->num);
3163 unregister_chrdev_region(dev, driver->num);
3164 driver->ttys = NULL;
3165 driver->termios = NULL;
3170 mutex_lock(&tty_mutex);
3171 list_add(&driver->tty_drivers, &tty_drivers);
3172 mutex_unlock(&tty_mutex);
3174 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3175 for (i = 0; i < driver->num; i++) {
3176 d = tty_register_device(driver, i, NULL);
3183 proc_tty_register_driver(driver);
3184 driver->flags |= TTY_DRIVER_INSTALLED;
3188 for (i--; i >= 0; i--)
3189 tty_unregister_device(driver, i);
3191 mutex_lock(&tty_mutex);
3192 list_del(&driver->tty_drivers);
3193 mutex_unlock(&tty_mutex);
3195 unregister_chrdev_region(dev, driver->num);
3196 driver->ttys = NULL;
3197 driver->termios = NULL;
3202 EXPORT_SYMBOL(tty_register_driver);
3205 * Called by a tty driver to unregister itself.
3207 int tty_unregister_driver(struct tty_driver *driver)
3211 if (driver->refcount)
3214 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3216 mutex_lock(&tty_mutex);
3217 list_del(&driver->tty_drivers);
3218 mutex_unlock(&tty_mutex);
3222 EXPORT_SYMBOL(tty_unregister_driver);
3224 dev_t tty_devnum(struct tty_struct *tty)
3226 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3228 EXPORT_SYMBOL(tty_devnum);
3230 void proc_clear_tty(struct task_struct *p)
3232 unsigned long flags;
3233 struct tty_struct *tty;
3234 spin_lock_irqsave(&p->sighand->siglock, flags);
3235 tty = p->signal->tty;
3236 p->signal->tty = NULL;
3237 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3241 /* Called under the sighand lock */
3243 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3246 unsigned long flags;
3247 /* We should not have a session or pgrp to put here but.... */
3248 spin_lock_irqsave(&tty->ctrl_lock, flags);
3249 put_pid(tty->session);
3251 tty->pgrp = get_pid(task_pgrp(tsk));
3252 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3253 tty->session = get_pid(task_session(tsk));
3254 if (tsk->signal->tty) {
3255 printk(KERN_DEBUG "tty not NULL!!\n");
3256 tty_kref_put(tsk->signal->tty);
3259 put_pid(tsk->signal->tty_old_pgrp);
3260 tsk->signal->tty = tty_kref_get(tty);
3261 tsk->signal->tty_old_pgrp = NULL;
3264 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3266 spin_lock_irq(&tsk->sighand->siglock);
3267 __proc_set_tty(tsk, tty);
3268 spin_unlock_irq(&tsk->sighand->siglock);
3271 struct tty_struct *get_current_tty(void)
3273 struct tty_struct *tty;
3274 unsigned long flags;
3276 spin_lock_irqsave(¤t->sighand->siglock, flags);
3277 tty = tty_kref_get(current->signal->tty);
3278 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3281 EXPORT_SYMBOL_GPL(get_current_tty);
3283 void tty_default_fops(struct file_operations *fops)
3289 * Initialize the console device. This is called *early*, so
3290 * we can't necessarily depend on lots of kernel help here.
3291 * Just do some early initializations, and do the complex setup
3294 void __init console_init(void)
3298 /* Setup the default TTY line discipline. */
3302 * set up the console device so that later boot sequences can
3303 * inform about problems etc..
3305 call = __con_initcall_start;
3306 while (call < __con_initcall_end) {
3312 static char *tty_devnode(struct device *dev, mode_t *mode)
3316 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3317 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3322 static int __init tty_class_init(void)
3324 tty_class = class_create(THIS_MODULE, "tty");
3325 if (IS_ERR(tty_class))
3326 return PTR_ERR(tty_class);
3327 tty_class->devnode = tty_devnode;
3331 postcore_initcall(tty_class_init);
3333 /* 3/2004 jmc: why do these devices exist? */
3334 static struct cdev tty_cdev, console_cdev;
3336 static ssize_t show_cons_active(struct device *dev,
3337 struct device_attribute *attr, char *buf)
3339 struct console *cs[16];
3345 for_each_console(c) {
3350 if ((c->flags & CON_ENABLED) == 0)
3353 if (i >= ARRAY_SIZE(cs))
3357 count += sprintf(buf + count, "%s%d%c",
3358 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3363 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3365 static struct device *consdev;
3367 void console_sysfs_notify(void)
3370 sysfs_notify(&consdev->kobj, NULL, "active");
3374 * Ok, now we can initialize the rest of the tty devices and can count
3375 * on memory allocations, interrupts etc..
3377 int __init tty_init(void)
3379 cdev_init(&tty_cdev, &tty_fops);
3380 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3381 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3382 panic("Couldn't register /dev/tty driver\n");
3383 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3385 cdev_init(&console_cdev, &console_fops);
3386 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3387 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3388 panic("Couldn't register /dev/console driver\n");
3389 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3391 if (IS_ERR(consdev))
3394 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3397 vty_init(&console_fops);