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 /* Associate a new file with the tty structure */
198 int tty_add_file(struct tty_struct *tty, struct file *file)
200 struct tty_file_private *priv;
202 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
208 file->private_data = priv;
210 spin_lock(&tty_files_lock);
211 list_add(&priv->list, &tty->tty_files);
212 spin_unlock(&tty_files_lock);
217 /* Delete file from its tty */
218 void tty_del_file(struct file *file)
220 struct tty_file_private *priv = file->private_data;
222 spin_lock(&tty_files_lock);
223 list_del(&priv->list);
224 spin_unlock(&tty_files_lock);
225 file->private_data = NULL;
230 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
233 * tty_name - return tty naming
234 * @tty: tty structure
235 * @buf: buffer for output
237 * Convert a tty structure into a name. The name reflects the kernel
238 * naming policy and if udev is in use may not reflect user space
243 char *tty_name(struct tty_struct *tty, char *buf)
245 if (!tty) /* Hmm. NULL pointer. That's fun. */
246 strcpy(buf, "NULL tty");
248 strcpy(buf, tty->name);
252 EXPORT_SYMBOL(tty_name);
254 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
257 #ifdef TTY_PARANOIA_CHECK
260 "null TTY for (%d:%d) in %s\n",
261 imajor(inode), iminor(inode), routine);
264 if (tty->magic != TTY_MAGIC) {
266 "bad magic number for tty struct (%d:%d) in %s\n",
267 imajor(inode), iminor(inode), routine);
274 static int check_tty_count(struct tty_struct *tty, const char *routine)
276 #ifdef CHECK_TTY_COUNT
280 spin_lock(&tty_files_lock);
281 list_for_each(p, &tty->tty_files) {
284 spin_unlock(&tty_files_lock);
285 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
286 tty->driver->subtype == PTY_TYPE_SLAVE &&
287 tty->link && tty->link->count)
289 if (tty->count != count) {
290 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
291 "!= #fd's(%d) in %s\n",
292 tty->name, tty->count, count, routine);
300 * get_tty_driver - find device of a tty
301 * @dev_t: device identifier
302 * @index: returns the index of the tty
304 * This routine returns a tty driver structure, given a device number
305 * and also passes back the index number.
307 * Locking: caller must hold tty_mutex
310 static struct tty_driver *get_tty_driver(dev_t device, int *index)
312 struct tty_driver *p;
314 list_for_each_entry(p, &tty_drivers, tty_drivers) {
315 dev_t base = MKDEV(p->major, p->minor_start);
316 if (device < base || device >= base + p->num)
318 *index = device - base;
319 return tty_driver_kref_get(p);
324 #ifdef CONFIG_CONSOLE_POLL
327 * tty_find_polling_driver - find device of a polled tty
328 * @name: name string to match
329 * @line: pointer to resulting tty line nr
331 * This routine returns a tty driver structure, given a name
332 * and the condition that the tty driver is capable of polled
335 struct tty_driver *tty_find_polling_driver(char *name, int *line)
337 struct tty_driver *p, *res = NULL;
342 for (str = name; *str; str++)
343 if ((*str >= '0' && *str <= '9') || *str == ',')
349 tty_line = simple_strtoul(str, &str, 10);
351 mutex_lock(&tty_mutex);
352 /* Search through the tty devices to look for a match */
353 list_for_each_entry(p, &tty_drivers, tty_drivers) {
354 if (strncmp(name, p->name, len) != 0)
362 if (tty_line >= 0 && tty_line < p->num && p->ops &&
363 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
364 res = tty_driver_kref_get(p);
369 mutex_unlock(&tty_mutex);
373 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
377 * tty_check_change - check for POSIX terminal changes
380 * If we try to write to, or set the state of, a terminal and we're
381 * not in the foreground, send a SIGTTOU. If the signal is blocked or
382 * ignored, go ahead and perform the operation. (POSIX 7.2)
387 int tty_check_change(struct tty_struct *tty)
392 if (current->signal->tty != tty)
395 spin_lock_irqsave(&tty->ctrl_lock, flags);
398 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
401 if (task_pgrp(current) == tty->pgrp)
403 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
404 if (is_ignored(SIGTTOU))
406 if (is_current_pgrp_orphaned()) {
410 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
411 set_thread_flag(TIF_SIGPENDING);
416 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
420 EXPORT_SYMBOL(tty_check_change);
422 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
423 size_t count, loff_t *ppos)
428 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
429 size_t count, loff_t *ppos)
434 /* No kernel lock held - none needed ;) */
435 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
437 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
440 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
443 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
446 static long hung_up_tty_compat_ioctl(struct file *file,
447 unsigned int cmd, unsigned long arg)
449 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
452 static const struct file_operations tty_fops = {
457 .unlocked_ioctl = tty_ioctl,
458 .compat_ioctl = tty_compat_ioctl,
460 .release = tty_release,
461 .fasync = tty_fasync,
464 static const struct file_operations console_fops = {
467 .write = redirected_tty_write,
469 .unlocked_ioctl = tty_ioctl,
470 .compat_ioctl = tty_compat_ioctl,
472 .release = tty_release,
473 .fasync = tty_fasync,
476 static const struct file_operations hung_up_tty_fops = {
478 .read = hung_up_tty_read,
479 .write = hung_up_tty_write,
480 .poll = hung_up_tty_poll,
481 .unlocked_ioctl = hung_up_tty_ioctl,
482 .compat_ioctl = hung_up_tty_compat_ioctl,
483 .release = tty_release,
486 static DEFINE_SPINLOCK(redirect_lock);
487 static struct file *redirect;
490 * tty_wakeup - request more data
493 * Internal and external helper for wakeups of tty. This function
494 * informs the line discipline if present that the driver is ready
495 * to receive more output data.
498 void tty_wakeup(struct tty_struct *tty)
500 struct tty_ldisc *ld;
502 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
503 ld = tty_ldisc_ref(tty);
505 if (ld->ops->write_wakeup)
506 ld->ops->write_wakeup(tty);
510 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
513 EXPORT_SYMBOL_GPL(tty_wakeup);
516 * __tty_hangup - actual handler for hangup events
519 * This can be called by the "eventd" kernel thread. That is process
520 * synchronous but doesn't hold any locks, so we need to make sure we
521 * have the appropriate locks for what we're doing.
523 * The hangup event clears any pending redirections onto the hung up
524 * device. It ensures future writes will error and it does the needed
525 * line discipline hangup and signal delivery. The tty object itself
530 * redirect lock for undoing redirection
531 * file list lock for manipulating list of ttys
532 * tty_ldisc_lock from called functions
533 * termios_mutex resetting termios data
534 * tasklist_lock to walk task list for hangup event
535 * ->siglock to protect ->signal/->sighand
537 void __tty_hangup(struct tty_struct *tty)
539 struct file *cons_filp = NULL;
540 struct file *filp, *f = NULL;
541 struct task_struct *p;
542 struct tty_file_private *priv;
543 int closecount = 0, n;
551 spin_lock(&redirect_lock);
552 if (redirect && file_tty(redirect) == tty) {
556 spin_unlock(&redirect_lock);
560 /* some functions below drop BTM, so we need this bit */
561 set_bit(TTY_HUPPING, &tty->flags);
563 /* inuse_filps is protected by the single tty lock,
564 this really needs to change if we want to flush the
565 workqueue with the lock held */
566 check_tty_count(tty, "tty_hangup");
568 spin_lock(&tty_files_lock);
569 /* This breaks for file handles being sent over AF_UNIX sockets ? */
570 list_for_each_entry(priv, &tty->tty_files, list) {
572 if (filp->f_op->write == redirected_tty_write)
574 if (filp->f_op->write != tty_write)
577 __tty_fasync(-1, filp, 0); /* can't block */
578 filp->f_op = &hung_up_tty_fops;
580 spin_unlock(&tty_files_lock);
583 * it drops BTM and thus races with reopen
584 * we protect the race by TTY_HUPPING
586 tty_ldisc_hangup(tty);
588 read_lock(&tasklist_lock);
590 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
591 spin_lock_irq(&p->sighand->siglock);
592 if (p->signal->tty == tty) {
593 p->signal->tty = NULL;
594 /* We defer the dereferences outside fo
598 if (!p->signal->leader) {
599 spin_unlock_irq(&p->sighand->siglock);
602 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
603 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
604 put_pid(p->signal->tty_old_pgrp); /* A noop */
605 spin_lock_irqsave(&tty->ctrl_lock, flags);
607 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
608 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
609 spin_unlock_irq(&p->sighand->siglock);
610 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
612 read_unlock(&tasklist_lock);
614 spin_lock_irqsave(&tty->ctrl_lock, flags);
615 clear_bit(TTY_THROTTLED, &tty->flags);
616 clear_bit(TTY_PUSH, &tty->flags);
617 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
618 put_pid(tty->session);
622 tty->ctrl_status = 0;
623 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
625 /* Account for the p->signal references we killed */
630 * If one of the devices matches a console pointer, we
631 * cannot just call hangup() because that will cause
632 * tty->count and state->count to go out of sync.
633 * So we just call close() the right number of times.
637 for (n = 0; n < closecount; n++)
638 tty->ops->close(tty, cons_filp);
639 } else if (tty->ops->hangup)
640 (tty->ops->hangup)(tty);
642 * We don't want to have driver/ldisc interactions beyond
643 * the ones we did here. The driver layer expects no
644 * calls after ->hangup() from the ldisc side. However we
645 * can't yet guarantee all that.
647 set_bit(TTY_HUPPED, &tty->flags);
648 clear_bit(TTY_HUPPING, &tty->flags);
649 tty_ldisc_enable(tty);
657 static void do_tty_hangup(struct work_struct *work)
659 struct tty_struct *tty =
660 container_of(work, struct tty_struct, hangup_work);
666 * tty_hangup - trigger a hangup event
667 * @tty: tty to hangup
669 * A carrier loss (virtual or otherwise) has occurred on this like
670 * schedule a hangup sequence to run after this event.
673 void tty_hangup(struct tty_struct *tty)
675 #ifdef TTY_DEBUG_HANGUP
677 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
679 schedule_work(&tty->hangup_work);
682 EXPORT_SYMBOL(tty_hangup);
685 * tty_vhangup - process vhangup
686 * @tty: tty to hangup
688 * The user has asked via system call for the terminal to be hung up.
689 * We do this synchronously so that when the syscall returns the process
690 * is complete. That guarantee is necessary for security reasons.
693 void tty_vhangup(struct tty_struct *tty)
695 #ifdef TTY_DEBUG_HANGUP
698 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
703 EXPORT_SYMBOL(tty_vhangup);
707 * tty_vhangup_self - process vhangup for own ctty
709 * Perform a vhangup on the current controlling tty
712 void tty_vhangup_self(void)
714 struct tty_struct *tty;
716 tty = get_current_tty();
724 * tty_hung_up_p - was tty hung up
725 * @filp: file pointer of tty
727 * Return true if the tty has been subject to a vhangup or a carrier
731 int tty_hung_up_p(struct file *filp)
733 return (filp->f_op == &hung_up_tty_fops);
736 EXPORT_SYMBOL(tty_hung_up_p);
738 static void session_clear_tty(struct pid *session)
740 struct task_struct *p;
741 do_each_pid_task(session, PIDTYPE_SID, p) {
743 } while_each_pid_task(session, PIDTYPE_SID, p);
747 * disassociate_ctty - disconnect controlling tty
748 * @on_exit: true if exiting so need to "hang up" the session
750 * This function is typically called only by the session leader, when
751 * it wants to disassociate itself from its controlling tty.
753 * It performs the following functions:
754 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
755 * (2) Clears the tty from being controlling the session
756 * (3) Clears the controlling tty for all processes in the
759 * The argument on_exit is set to 1 if called when a process is
760 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
763 * BTM is taken for hysterical raisins, and held when
764 * called from no_tty().
765 * tty_mutex is taken to protect tty
766 * ->siglock is taken to protect ->signal/->sighand
767 * tasklist_lock is taken to walk process list for sessions
768 * ->siglock is taken to protect ->signal/->sighand
771 void disassociate_ctty(int on_exit)
773 struct tty_struct *tty;
774 struct pid *tty_pgrp = NULL;
776 if (!current->signal->leader)
779 tty = get_current_tty();
781 tty_pgrp = get_pid(tty->pgrp);
783 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
787 } else if (on_exit) {
788 struct pid *old_pgrp;
789 spin_lock_irq(¤t->sighand->siglock);
790 old_pgrp = current->signal->tty_old_pgrp;
791 current->signal->tty_old_pgrp = NULL;
792 spin_unlock_irq(¤t->sighand->siglock);
794 kill_pgrp(old_pgrp, SIGHUP, on_exit);
795 kill_pgrp(old_pgrp, SIGCONT, on_exit);
801 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
803 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
807 spin_lock_irq(¤t->sighand->siglock);
808 put_pid(current->signal->tty_old_pgrp);
809 current->signal->tty_old_pgrp = NULL;
810 spin_unlock_irq(¤t->sighand->siglock);
812 tty = get_current_tty();
815 spin_lock_irqsave(&tty->ctrl_lock, flags);
816 put_pid(tty->session);
820 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
823 #ifdef TTY_DEBUG_HANGUP
824 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
829 /* Now clear signal->tty under the lock */
830 read_lock(&tasklist_lock);
831 session_clear_tty(task_session(current));
832 read_unlock(&tasklist_lock);
837 * no_tty - Ensure the current process does not have a controlling tty
841 struct task_struct *tsk = current;
843 disassociate_ctty(0);
850 * stop_tty - propagate flow control
853 * Perform flow control to the driver. For PTY/TTY pairs we
854 * must also propagate the TIOCKPKT status. May be called
855 * on an already stopped device and will not re-call the driver
858 * This functionality is used by both the line disciplines for
859 * halting incoming flow and by the driver. It may therefore be
860 * called from any context, may be under the tty atomic_write_lock
864 * Uses the tty control lock internally
867 void stop_tty(struct tty_struct *tty)
870 spin_lock_irqsave(&tty->ctrl_lock, flags);
872 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
876 if (tty->link && tty->link->packet) {
877 tty->ctrl_status &= ~TIOCPKT_START;
878 tty->ctrl_status |= TIOCPKT_STOP;
879 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
881 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
883 (tty->ops->stop)(tty);
886 EXPORT_SYMBOL(stop_tty);
889 * start_tty - propagate flow control
892 * Start a tty that has been stopped if at all possible. Perform
893 * any necessary wakeups and propagate the TIOCPKT status. If this
894 * is the tty was previous stopped and is being started then the
895 * driver start method is invoked and the line discipline woken.
901 void start_tty(struct tty_struct *tty)
904 spin_lock_irqsave(&tty->ctrl_lock, flags);
905 if (!tty->stopped || tty->flow_stopped) {
906 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
910 if (tty->link && tty->link->packet) {
911 tty->ctrl_status &= ~TIOCPKT_STOP;
912 tty->ctrl_status |= TIOCPKT_START;
913 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
915 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
917 (tty->ops->start)(tty);
918 /* If we have a running line discipline it may need kicking */
922 EXPORT_SYMBOL(start_tty);
925 * tty_read - read method for tty device files
926 * @file: pointer to tty file
928 * @count: size of user buffer
931 * Perform the read system call function on this terminal device. Checks
932 * for hung up devices before calling the line discipline method.
935 * Locks the line discipline internally while needed. Multiple
936 * read calls may be outstanding in parallel.
939 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
943 struct inode *inode = file->f_path.dentry->d_inode;
944 struct tty_struct *tty = file_tty(file);
945 struct tty_ldisc *ld;
947 if (tty_paranoia_check(tty, inode, "tty_read"))
949 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
952 /* We want to wait for the line discipline to sort out in this
954 ld = tty_ldisc_ref_wait(tty);
956 i = (ld->ops->read)(tty, file, buf, count);
961 inode->i_atime = current_fs_time(inode->i_sb);
965 void tty_write_unlock(struct tty_struct *tty)
966 __releases(&tty->atomic_write_lock)
968 mutex_unlock(&tty->atomic_write_lock);
969 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
972 int tty_write_lock(struct tty_struct *tty, int ndelay)
973 __acquires(&tty->atomic_write_lock)
975 if (!mutex_trylock(&tty->atomic_write_lock)) {
978 if (mutex_lock_interruptible(&tty->atomic_write_lock))
985 * Split writes up in sane blocksizes to avoid
986 * denial-of-service type attacks
988 static inline ssize_t do_tty_write(
989 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
990 struct tty_struct *tty,
992 const char __user *buf,
995 ssize_t ret, written = 0;
998 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1003 * We chunk up writes into a temporary buffer. This
1004 * simplifies low-level drivers immensely, since they
1005 * don't have locking issues and user mode accesses.
1007 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1010 * The default chunk-size is 2kB, because the NTTY
1011 * layer has problems with bigger chunks. It will
1012 * claim to be able to handle more characters than
1015 * FIXME: This can probably go away now except that 64K chunks
1016 * are too likely to fail unless switched to vmalloc...
1019 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1024 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1025 if (tty->write_cnt < chunk) {
1026 unsigned char *buf_chunk;
1031 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1036 kfree(tty->write_buf);
1037 tty->write_cnt = chunk;
1038 tty->write_buf = buf_chunk;
1041 /* Do the write .. */
1043 size_t size = count;
1047 if (copy_from_user(tty->write_buf, buf, size))
1049 ret = write(tty, file, tty->write_buf, size);
1058 if (signal_pending(current))
1063 struct inode *inode = file->f_path.dentry->d_inode;
1064 inode->i_mtime = current_fs_time(inode->i_sb);
1068 tty_write_unlock(tty);
1073 * tty_write_message - write a message to a certain tty, not just the console.
1074 * @tty: the destination tty_struct
1075 * @msg: the message to write
1077 * This is used for messages that need to be redirected to a specific tty.
1078 * We don't put it into the syslog queue right now maybe in the future if
1081 * We must still hold the BTM and test the CLOSING flag for the moment.
1084 void tty_write_message(struct tty_struct *tty, char *msg)
1087 mutex_lock(&tty->atomic_write_lock);
1089 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1091 tty->ops->write(tty, msg, strlen(msg));
1094 tty_write_unlock(tty);
1101 * tty_write - write method for tty device file
1102 * @file: tty file pointer
1103 * @buf: user data to write
1104 * @count: bytes to write
1107 * Write data to a tty device via the line discipline.
1110 * Locks the line discipline as required
1111 * Writes to the tty driver are serialized by the atomic_write_lock
1112 * and are then processed in chunks to the device. The line discipline
1113 * write method will not be invoked in parallel for each device.
1116 static ssize_t tty_write(struct file *file, const char __user *buf,
1117 size_t count, loff_t *ppos)
1119 struct inode *inode = file->f_path.dentry->d_inode;
1120 struct tty_struct *tty = file_tty(file);
1121 struct tty_ldisc *ld;
1124 if (tty_paranoia_check(tty, inode, "tty_write"))
1126 if (!tty || !tty->ops->write ||
1127 (test_bit(TTY_IO_ERROR, &tty->flags)))
1129 /* Short term debug to catch buggy drivers */
1130 if (tty->ops->write_room == NULL)
1131 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1133 ld = tty_ldisc_ref_wait(tty);
1134 if (!ld->ops->write)
1137 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1138 tty_ldisc_deref(ld);
1142 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1143 size_t count, loff_t *ppos)
1145 struct file *p = NULL;
1147 spin_lock(&redirect_lock);
1152 spin_unlock(&redirect_lock);
1156 res = vfs_write(p, buf, count, &p->f_pos);
1160 return tty_write(file, buf, count, ppos);
1163 static char ptychar[] = "pqrstuvwxyzabcde";
1166 * pty_line_name - generate name for a pty
1167 * @driver: the tty driver in use
1168 * @index: the minor number
1169 * @p: output buffer of at least 6 bytes
1171 * Generate a name from a driver reference and write it to the output
1176 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1178 int i = index + driver->name_base;
1179 /* ->name is initialized to "ttyp", but "tty" is expected */
1180 sprintf(p, "%s%c%x",
1181 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1182 ptychar[i >> 4 & 0xf], i & 0xf);
1186 * tty_line_name - generate name for a tty
1187 * @driver: the tty driver in use
1188 * @index: the minor number
1189 * @p: output buffer of at least 7 bytes
1191 * Generate a name from a driver reference and write it to the output
1196 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1198 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1202 * tty_driver_lookup_tty() - find an existing tty, if any
1203 * @driver: the driver for the tty
1204 * @idx: the minor number
1206 * Return the tty, if found or ERR_PTR() otherwise.
1208 * Locking: tty_mutex must be held. If tty is found, the mutex must
1209 * be held until the 'fast-open' is also done. Will change once we
1210 * have refcounting in the driver and per driver locking
1212 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1213 struct inode *inode, int idx)
1215 struct tty_struct *tty;
1217 if (driver->ops->lookup)
1218 return driver->ops->lookup(driver, inode, idx);
1220 tty = driver->ttys[idx];
1225 * tty_init_termios - helper for termios setup
1226 * @tty: the tty to set up
1228 * Initialise the termios structures for this tty. Thus runs under
1229 * the tty_mutex currently so we can be relaxed about ordering.
1232 int tty_init_termios(struct tty_struct *tty)
1234 struct ktermios *tp;
1235 int idx = tty->index;
1237 tp = tty->driver->termios[idx];
1239 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1242 memcpy(tp, &tty->driver->init_termios,
1243 sizeof(struct ktermios));
1244 tty->driver->termios[idx] = tp;
1247 tty->termios_locked = tp + 1;
1249 /* Compatibility until drivers always set this */
1250 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1251 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1254 EXPORT_SYMBOL_GPL(tty_init_termios);
1257 * tty_driver_install_tty() - install a tty entry in the driver
1258 * @driver: the driver for the tty
1261 * Install a tty object into the driver tables. The tty->index field
1262 * will be set by the time this is called. This method is responsible
1263 * for ensuring any need additional structures are allocated and
1266 * Locking: tty_mutex for now
1268 static int tty_driver_install_tty(struct tty_driver *driver,
1269 struct tty_struct *tty)
1271 int idx = tty->index;
1274 if (driver->ops->install) {
1275 ret = driver->ops->install(driver, tty);
1279 if (tty_init_termios(tty) == 0) {
1280 tty_driver_kref_get(driver);
1282 driver->ttys[idx] = tty;
1289 * tty_driver_remove_tty() - remove a tty from the driver tables
1290 * @driver: the driver for the tty
1291 * @idx: the minor number
1293 * Remvoe a tty object from the driver tables. The tty->index field
1294 * will be set by the time this is called.
1296 * Locking: tty_mutex for now
1298 static void tty_driver_remove_tty(struct tty_driver *driver,
1299 struct tty_struct *tty)
1301 if (driver->ops->remove)
1302 driver->ops->remove(driver, tty);
1304 driver->ttys[tty->index] = NULL;
1308 * tty_reopen() - fast re-open of an open tty
1309 * @tty - the tty to open
1311 * Return 0 on success, -errno on error.
1313 * Locking: tty_mutex must be held from the time the tty was found
1314 * till this open completes.
1316 static int tty_reopen(struct tty_struct *tty)
1318 struct tty_driver *driver = tty->driver;
1320 if (test_bit(TTY_CLOSING, &tty->flags) ||
1321 test_bit(TTY_HUPPING, &tty->flags) ||
1322 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1325 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1326 driver->subtype == PTY_TYPE_MASTER) {
1328 * special case for PTY masters: only one open permitted,
1329 * and the slave side open count is incremented as well.
1337 tty->driver = driver; /* N.B. why do this every time?? */
1339 mutex_lock(&tty->ldisc_mutex);
1340 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1341 mutex_unlock(&tty->ldisc_mutex);
1347 * tty_init_dev - initialise a tty device
1348 * @driver: tty driver we are opening a device on
1349 * @idx: device index
1350 * @ret_tty: returned tty structure
1351 * @first_ok: ok to open a new device (used by ptmx)
1353 * Prepare a tty device. This may not be a "new" clean device but
1354 * could also be an active device. The pty drivers require special
1355 * handling because of this.
1358 * The function is called under the tty_mutex, which
1359 * protects us from the tty struct or driver itself going away.
1361 * On exit the tty device has the line discipline attached and
1362 * a reference count of 1. If a pair was created for pty/tty use
1363 * and the other was a pty master then it too has a reference count of 1.
1365 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1366 * failed open. The new code protects the open with a mutex, so it's
1367 * really quite straightforward. The mutex locking can probably be
1368 * relaxed for the (most common) case of reopening a tty.
1371 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1374 struct tty_struct *tty;
1377 /* Check if pty master is being opened multiple times */
1378 if (driver->subtype == PTY_TYPE_MASTER &&
1379 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1380 return ERR_PTR(-EIO);
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);
1401 retval = tty_driver_install_tty(driver, tty);
1403 goto err_deinit_tty;
1406 * Structures all installed ... call the ldisc open routines.
1407 * If we fail here just call release_tty to clean up. No need
1408 * to decrement the use counts, as release_tty doesn't care.
1410 retval = tty_ldisc_setup(tty, tty->link);
1412 goto err_release_tty;
1416 deinitialize_tty_struct(tty);
1417 free_tty_struct(tty);
1419 module_put(driver->owner);
1420 return ERR_PTR(retval);
1422 /* call the tty release_tty routine to clean out this slot */
1424 printk_ratelimited(KERN_INFO "tty_init_dev: ldisc open failed, "
1425 "clearing slot %d\n", idx);
1426 release_tty(tty, idx);
1427 return ERR_PTR(retval);
1430 void tty_free_termios(struct tty_struct *tty)
1432 struct ktermios *tp;
1433 int idx = tty->index;
1434 /* Kill this flag and push into drivers for locking etc */
1435 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1436 /* FIXME: Locking on ->termios array */
1438 tty->driver->termios[idx] = NULL;
1442 EXPORT_SYMBOL(tty_free_termios);
1444 void tty_shutdown(struct tty_struct *tty)
1446 tty_driver_remove_tty(tty->driver, tty);
1447 tty_free_termios(tty);
1449 EXPORT_SYMBOL(tty_shutdown);
1452 * release_one_tty - release tty structure memory
1453 * @kref: kref of tty we are obliterating
1455 * Releases memory associated with a tty structure, and clears out the
1456 * driver table slots. This function is called when a device is no longer
1457 * in use. It also gets called when setup of a device fails.
1460 * tty_mutex - sometimes only
1461 * takes the file list lock internally when working on the list
1462 * of ttys that the driver keeps.
1464 * This method gets called from a work queue so that the driver private
1465 * cleanup ops can sleep (needed for USB at least)
1467 static void release_one_tty(struct work_struct *work)
1469 struct tty_struct *tty =
1470 container_of(work, struct tty_struct, hangup_work);
1471 struct tty_driver *driver = tty->driver;
1473 if (tty->ops->cleanup)
1474 tty->ops->cleanup(tty);
1477 tty_driver_kref_put(driver);
1478 module_put(driver->owner);
1480 spin_lock(&tty_files_lock);
1481 list_del_init(&tty->tty_files);
1482 spin_unlock(&tty_files_lock);
1485 put_pid(tty->session);
1486 free_tty_struct(tty);
1489 static void queue_release_one_tty(struct kref *kref)
1491 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1493 if (tty->ops->shutdown)
1494 tty->ops->shutdown(tty);
1498 /* The hangup queue is now free so we can reuse it rather than
1499 waste a chunk of memory for each port */
1500 INIT_WORK(&tty->hangup_work, release_one_tty);
1501 schedule_work(&tty->hangup_work);
1505 * tty_kref_put - release a tty kref
1508 * Release a reference to a tty device and if need be let the kref
1509 * layer destruct the object for us
1512 void tty_kref_put(struct tty_struct *tty)
1515 kref_put(&tty->kref, queue_release_one_tty);
1517 EXPORT_SYMBOL(tty_kref_put);
1520 * release_tty - release tty structure memory
1522 * Release both @tty and a possible linked partner (think pty pair),
1523 * and decrement the refcount of the backing module.
1526 * tty_mutex - sometimes only
1527 * takes the file list lock internally when working on the list
1528 * of ttys that the driver keeps.
1529 * FIXME: should we require tty_mutex is held here ??
1532 static void release_tty(struct tty_struct *tty, int idx)
1534 /* This should always be true but check for the moment */
1535 WARN_ON(tty->index != idx);
1538 tty_kref_put(tty->link);
1543 * tty_release - vfs callback for close
1544 * @inode: inode of tty
1545 * @filp: file pointer for handle to tty
1547 * Called the last time each file handle is closed that references
1548 * this tty. There may however be several such references.
1551 * Takes bkl. See tty_release_dev
1553 * Even releasing the tty structures is a tricky business.. We have
1554 * to be very careful that the structures are all released at the
1555 * same time, as interrupts might otherwise get the wrong pointers.
1557 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1558 * lead to double frees or releasing memory still in use.
1561 int tty_release(struct inode *inode, struct file *filp)
1563 struct tty_struct *tty = file_tty(filp);
1564 struct tty_struct *o_tty;
1565 int pty_master, tty_closing, o_tty_closing, do_sleep;
1570 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1574 check_tty_count(tty, "tty_release_dev");
1576 __tty_fasync(-1, filp, 0);
1579 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1580 tty->driver->subtype == PTY_TYPE_MASTER);
1581 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1584 #ifdef TTY_PARANOIA_CHECK
1585 if (idx < 0 || idx >= tty->driver->num) {
1586 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1587 "free (%s)\n", tty->name);
1592 if (tty != tty->driver->ttys[idx]) {
1594 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1595 "for (%s)\n", idx, tty->name);
1598 if (tty->termios != tty->driver->termios[idx]) {
1600 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1608 #ifdef TTY_DEBUG_HANGUP
1609 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1610 tty_name(tty, buf), tty->count);
1613 #ifdef TTY_PARANOIA_CHECK
1614 if (tty->driver->other &&
1615 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1616 if (o_tty != tty->driver->other->ttys[idx]) {
1618 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1619 "not o_tty for (%s)\n",
1623 if (o_tty->termios != tty->driver->other->termios[idx]) {
1625 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1626 "not o_termios for (%s)\n",
1630 if (o_tty->link != tty) {
1632 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1637 if (tty->ops->close)
1638 tty->ops->close(tty, filp);
1642 * Sanity check: if tty->count is going to zero, there shouldn't be
1643 * any waiters on tty->read_wait or tty->write_wait. We test the
1644 * wait queues and kick everyone out _before_ actually starting to
1645 * close. This ensures that we won't block while releasing the tty
1648 * The test for the o_tty closing is necessary, since the master and
1649 * slave sides may close in any order. If the slave side closes out
1650 * first, its count will be one, since the master side holds an open.
1651 * Thus this test wouldn't be triggered at the time the slave closes,
1654 * Note that it's possible for the tty to be opened again while we're
1655 * flushing out waiters. By recalculating the closing flags before
1656 * each iteration we avoid any problems.
1659 /* Guard against races with tty->count changes elsewhere and
1660 opens on /dev/tty */
1662 mutex_lock(&tty_mutex);
1664 tty_closing = tty->count <= 1;
1665 o_tty_closing = o_tty &&
1666 (o_tty->count <= (pty_master ? 1 : 0));
1670 if (waitqueue_active(&tty->read_wait)) {
1671 wake_up_poll(&tty->read_wait, POLLIN);
1674 if (waitqueue_active(&tty->write_wait)) {
1675 wake_up_poll(&tty->write_wait, POLLOUT);
1679 if (o_tty_closing) {
1680 if (waitqueue_active(&o_tty->read_wait)) {
1681 wake_up_poll(&o_tty->read_wait, POLLIN);
1684 if (waitqueue_active(&o_tty->write_wait)) {
1685 wake_up_poll(&o_tty->write_wait, POLLOUT);
1692 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1693 "active!\n", tty_name(tty, buf));
1695 mutex_unlock(&tty_mutex);
1700 * The closing flags are now consistent with the open counts on
1701 * both sides, and we've completed the last operation that could
1702 * block, so it's safe to proceed with closing.
1705 if (--o_tty->count < 0) {
1706 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1708 o_tty->count, tty_name(o_tty, buf));
1712 if (--tty->count < 0) {
1713 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1714 tty->count, tty_name(tty, buf));
1719 * We've decremented tty->count, so we need to remove this file
1720 * descriptor off the tty->tty_files list; this serves two
1722 * - check_tty_count sees the correct number of file descriptors
1723 * associated with this tty.
1724 * - do_tty_hangup no longer sees this file descriptor as
1725 * something that needs to be handled for hangups.
1730 * Perform some housekeeping before deciding whether to return.
1732 * Set the TTY_CLOSING flag if this was the last open. In the
1733 * case of a pty we may have to wait around for the other side
1734 * to close, and TTY_CLOSING makes sure we can't be reopened.
1737 set_bit(TTY_CLOSING, &tty->flags);
1739 set_bit(TTY_CLOSING, &o_tty->flags);
1742 * If _either_ side is closing, make sure there aren't any
1743 * processes that still think tty or o_tty is their controlling
1746 if (tty_closing || o_tty_closing) {
1747 read_lock(&tasklist_lock);
1748 session_clear_tty(tty->session);
1750 session_clear_tty(o_tty->session);
1751 read_unlock(&tasklist_lock);
1754 mutex_unlock(&tty_mutex);
1756 /* check whether both sides are closing ... */
1757 if (!tty_closing || (o_tty && !o_tty_closing)) {
1762 #ifdef TTY_DEBUG_HANGUP
1763 printk(KERN_DEBUG "freeing tty structure...");
1766 * Ask the line discipline code to release its structures
1768 tty_ldisc_release(tty, o_tty);
1770 * The release_tty function takes care of the details of clearing
1771 * the slots and preserving the termios structure.
1773 release_tty(tty, idx);
1775 /* Make this pty number available for reallocation */
1777 devpts_kill_index(inode, idx);
1783 * tty_open - open a tty device
1784 * @inode: inode of device file
1785 * @filp: file pointer to tty
1787 * tty_open and tty_release keep up the tty count that contains the
1788 * number of opens done on a tty. We cannot use the inode-count, as
1789 * different inodes might point to the same tty.
1791 * Open-counting is needed for pty masters, as well as for keeping
1792 * track of serial lines: DTR is dropped when the last close happens.
1793 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1795 * The termios state of a pty is reset on first open so that
1796 * settings don't persist across reuse.
1798 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1799 * tty->count should protect the rest.
1800 * ->siglock protects ->signal/->sighand
1803 static int tty_open(struct inode *inode, struct file *filp)
1805 struct tty_struct *tty = NULL;
1807 struct tty_driver *driver;
1809 dev_t device = inode->i_rdev;
1810 unsigned saved_flags = filp->f_flags;
1812 nonseekable_open(inode, filp);
1815 noctty = filp->f_flags & O_NOCTTY;
1819 mutex_lock(&tty_mutex);
1822 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1823 tty = get_current_tty();
1826 mutex_unlock(&tty_mutex);
1829 driver = tty_driver_kref_get(tty->driver);
1831 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1833 /* FIXME: Should we take a driver reference ? */
1838 if (device == MKDEV(TTY_MAJOR, 0)) {
1839 extern struct tty_driver *console_driver;
1840 driver = tty_driver_kref_get(console_driver);
1846 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1847 struct tty_driver *console_driver = console_device(&index);
1848 if (console_driver) {
1849 driver = tty_driver_kref_get(console_driver);
1851 /* Don't let /dev/console block */
1852 filp->f_flags |= O_NONBLOCK;
1858 mutex_unlock(&tty_mutex);
1862 driver = get_tty_driver(device, &index);
1865 mutex_unlock(&tty_mutex);
1870 /* check whether we're reopening an existing tty */
1871 tty = tty_driver_lookup_tty(driver, inode, index);
1875 mutex_unlock(&tty_mutex);
1876 return PTR_ERR(tty);
1881 retval = tty_reopen(tty);
1883 tty = ERR_PTR(retval);
1885 tty = tty_init_dev(driver, index, 0);
1887 mutex_unlock(&tty_mutex);
1888 tty_driver_kref_put(driver);
1891 return PTR_ERR(tty);
1894 retval = tty_add_file(tty, filp);
1897 tty_release(inode, filp);
1901 check_tty_count(tty, "tty_open");
1902 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1903 tty->driver->subtype == PTY_TYPE_MASTER)
1905 #ifdef TTY_DEBUG_HANGUP
1906 printk(KERN_DEBUG "opening %s...", tty->name);
1909 retval = tty->ops->open(tty, filp);
1912 filp->f_flags = saved_flags;
1914 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1915 !capable(CAP_SYS_ADMIN))
1919 #ifdef TTY_DEBUG_HANGUP
1920 printk(KERN_DEBUG "error %d in opening %s...", retval,
1923 tty_unlock(); /* need to call tty_release without BTM */
1924 tty_release(inode, filp);
1925 if (retval != -ERESTARTSYS)
1928 if (signal_pending(current))
1933 * Need to reset f_op in case a hangup happened.
1936 if (filp->f_op == &hung_up_tty_fops)
1937 filp->f_op = &tty_fops;
1944 mutex_lock(&tty_mutex);
1946 spin_lock_irq(¤t->sighand->siglock);
1948 current->signal->leader &&
1949 !current->signal->tty &&
1950 tty->session == NULL)
1951 __proc_set_tty(current, tty);
1952 spin_unlock_irq(¤t->sighand->siglock);
1954 mutex_unlock(&tty_mutex);
1961 * tty_poll - check tty status
1962 * @filp: file being polled
1963 * @wait: poll wait structures to update
1965 * Call the line discipline polling method to obtain the poll
1966 * status of the device.
1968 * Locking: locks called line discipline but ldisc poll method
1969 * may be re-entered freely by other callers.
1972 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1974 struct tty_struct *tty = file_tty(filp);
1975 struct tty_ldisc *ld;
1978 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1981 ld = tty_ldisc_ref_wait(tty);
1983 ret = (ld->ops->poll)(tty, filp, wait);
1984 tty_ldisc_deref(ld);
1988 static int __tty_fasync(int fd, struct file *filp, int on)
1990 struct tty_struct *tty = file_tty(filp);
1991 unsigned long flags;
1994 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1997 retval = fasync_helper(fd, filp, on, &tty->fasync);
2004 if (!waitqueue_active(&tty->read_wait))
2005 tty->minimum_to_wake = 1;
2006 spin_lock_irqsave(&tty->ctrl_lock, flags);
2009 type = PIDTYPE_PGID;
2011 pid = task_pid(current);
2015 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2016 retval = __f_setown(filp, pid, type, 0);
2021 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2022 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2029 static int tty_fasync(int fd, struct file *filp, int on)
2033 retval = __tty_fasync(fd, filp, on);
2039 * tiocsti - fake input character
2040 * @tty: tty to fake input into
2041 * @p: pointer to character
2043 * Fake input to a tty device. Does the necessary locking and
2046 * FIXME: does not honour flow control ??
2049 * Called functions take tty_ldisc_lock
2050 * current->signal->tty check is safe without locks
2052 * FIXME: may race normal receive processing
2055 static int tiocsti(struct tty_struct *tty, char __user *p)
2058 struct tty_ldisc *ld;
2060 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2062 if (get_user(ch, p))
2064 tty_audit_tiocsti(tty, ch);
2065 ld = tty_ldisc_ref_wait(tty);
2066 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2067 tty_ldisc_deref(ld);
2072 * tiocgwinsz - implement window query ioctl
2074 * @arg: user buffer for result
2076 * Copies the kernel idea of the window size into the user buffer.
2078 * Locking: tty->termios_mutex is taken to ensure the winsize data
2082 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2086 mutex_lock(&tty->termios_mutex);
2087 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2088 mutex_unlock(&tty->termios_mutex);
2090 return err ? -EFAULT: 0;
2094 * tty_do_resize - resize event
2095 * @tty: tty being resized
2096 * @rows: rows (character)
2097 * @cols: cols (character)
2099 * Update the termios variables and send the necessary signals to
2100 * peform a terminal resize correctly
2103 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2106 unsigned long flags;
2109 mutex_lock(&tty->termios_mutex);
2110 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2112 /* Get the PID values and reference them so we can
2113 avoid holding the tty ctrl lock while sending signals */
2114 spin_lock_irqsave(&tty->ctrl_lock, flags);
2115 pgrp = get_pid(tty->pgrp);
2116 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2119 kill_pgrp(pgrp, SIGWINCH, 1);
2124 mutex_unlock(&tty->termios_mutex);
2129 * tiocswinsz - implement window size set ioctl
2130 * @tty; tty side of tty
2131 * @arg: user buffer for result
2133 * Copies the user idea of the window size to the kernel. Traditionally
2134 * this is just advisory information but for the Linux console it
2135 * actually has driver level meaning and triggers a VC resize.
2138 * Driver dependent. The default do_resize method takes the
2139 * tty termios mutex and ctrl_lock. The console takes its own lock
2140 * then calls into the default method.
2143 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2145 struct winsize tmp_ws;
2146 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2149 if (tty->ops->resize)
2150 return tty->ops->resize(tty, &tmp_ws);
2152 return tty_do_resize(tty, &tmp_ws);
2156 * tioccons - allow admin to move logical console
2157 * @file: the file to become console
2159 * Allow the administrator to move the redirected console device
2161 * Locking: uses redirect_lock to guard the redirect information
2164 static int tioccons(struct file *file)
2166 if (!capable(CAP_SYS_ADMIN))
2168 if (file->f_op->write == redirected_tty_write) {
2170 spin_lock(&redirect_lock);
2173 spin_unlock(&redirect_lock);
2178 spin_lock(&redirect_lock);
2180 spin_unlock(&redirect_lock);
2185 spin_unlock(&redirect_lock);
2190 * fionbio - non blocking ioctl
2191 * @file: file to set blocking value
2192 * @p: user parameter
2194 * Historical tty interfaces had a blocking control ioctl before
2195 * the generic functionality existed. This piece of history is preserved
2196 * in the expected tty API of posix OS's.
2198 * Locking: none, the open file handle ensures it won't go away.
2201 static int fionbio(struct file *file, int __user *p)
2205 if (get_user(nonblock, p))
2208 spin_lock(&file->f_lock);
2210 file->f_flags |= O_NONBLOCK;
2212 file->f_flags &= ~O_NONBLOCK;
2213 spin_unlock(&file->f_lock);
2218 * tiocsctty - set controlling tty
2219 * @tty: tty structure
2220 * @arg: user argument
2222 * This ioctl is used to manage job control. It permits a session
2223 * leader to set this tty as the controlling tty for the session.
2226 * Takes tty_mutex() to protect tty instance
2227 * Takes tasklist_lock internally to walk sessions
2228 * Takes ->siglock() when updating signal->tty
2231 static int tiocsctty(struct tty_struct *tty, int arg)
2234 if (current->signal->leader && (task_session(current) == tty->session))
2237 mutex_lock(&tty_mutex);
2239 * The process must be a session leader and
2240 * not have a controlling tty already.
2242 if (!current->signal->leader || current->signal->tty) {
2249 * This tty is already the controlling
2250 * tty for another session group!
2252 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2256 read_lock(&tasklist_lock);
2257 session_clear_tty(tty->session);
2258 read_unlock(&tasklist_lock);
2264 proc_set_tty(current, tty);
2266 mutex_unlock(&tty_mutex);
2271 * tty_get_pgrp - return a ref counted pgrp pid
2274 * Returns a refcounted instance of the pid struct for the process
2275 * group controlling the tty.
2278 struct pid *tty_get_pgrp(struct tty_struct *tty)
2280 unsigned long flags;
2283 spin_lock_irqsave(&tty->ctrl_lock, flags);
2284 pgrp = get_pid(tty->pgrp);
2285 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2289 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2292 * tiocgpgrp - get process group
2293 * @tty: tty passed by user
2294 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2297 * Obtain the process group of the tty. If there is no process group
2300 * Locking: none. Reference to current->signal->tty is safe.
2303 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2308 * (tty == real_tty) is a cheap way of
2309 * testing if the tty is NOT a master pty.
2311 if (tty == real_tty && current->signal->tty != real_tty)
2313 pid = tty_get_pgrp(real_tty);
2314 ret = put_user(pid_vnr(pid), p);
2320 * tiocspgrp - attempt to set process group
2321 * @tty: tty passed by user
2322 * @real_tty: tty side device matching tty passed by user
2325 * Set the process group of the tty to the session passed. Only
2326 * permitted where the tty session is our session.
2328 * Locking: RCU, ctrl lock
2331 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2335 int retval = tty_check_change(real_tty);
2336 unsigned long flags;
2342 if (!current->signal->tty ||
2343 (current->signal->tty != real_tty) ||
2344 (real_tty->session != task_session(current)))
2346 if (get_user(pgrp_nr, p))
2351 pgrp = find_vpid(pgrp_nr);
2356 if (session_of_pgrp(pgrp) != task_session(current))
2359 spin_lock_irqsave(&tty->ctrl_lock, flags);
2360 put_pid(real_tty->pgrp);
2361 real_tty->pgrp = get_pid(pgrp);
2362 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2369 * tiocgsid - get session id
2370 * @tty: tty passed by user
2371 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2372 * @p: pointer to returned session id
2374 * Obtain the session id of the tty. If there is no session
2377 * Locking: none. Reference to current->signal->tty is safe.
2380 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2383 * (tty == real_tty) is a cheap way of
2384 * testing if the tty is NOT a master pty.
2386 if (tty == real_tty && current->signal->tty != real_tty)
2388 if (!real_tty->session)
2390 return put_user(pid_vnr(real_tty->session), p);
2394 * tiocsetd - set line discipline
2396 * @p: pointer to user data
2398 * Set the line discipline according to user request.
2400 * Locking: see tty_set_ldisc, this function is just a helper
2403 static int tiocsetd(struct tty_struct *tty, int __user *p)
2408 if (get_user(ldisc, p))
2411 ret = tty_set_ldisc(tty, ldisc);
2417 * send_break - performed time break
2418 * @tty: device to break on
2419 * @duration: timeout in mS
2421 * Perform a timed break on hardware that lacks its own driver level
2422 * timed break functionality.
2425 * atomic_write_lock serializes
2429 static int send_break(struct tty_struct *tty, unsigned int duration)
2433 if (tty->ops->break_ctl == NULL)
2436 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2437 retval = tty->ops->break_ctl(tty, duration);
2439 /* Do the work ourselves */
2440 if (tty_write_lock(tty, 0) < 0)
2442 retval = tty->ops->break_ctl(tty, -1);
2445 if (!signal_pending(current))
2446 msleep_interruptible(duration);
2447 retval = tty->ops->break_ctl(tty, 0);
2449 tty_write_unlock(tty);
2450 if (signal_pending(current))
2457 * tty_tiocmget - get modem status
2459 * @file: user file pointer
2460 * @p: pointer to result
2462 * Obtain the modem status bits from the tty driver if the feature
2463 * is supported. Return -EINVAL if it is not available.
2465 * Locking: none (up to the driver)
2468 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2470 int retval = -EINVAL;
2472 if (tty->ops->tiocmget) {
2473 retval = tty->ops->tiocmget(tty);
2476 retval = put_user(retval, p);
2482 * tty_tiocmset - set modem status
2484 * @cmd: command - clear bits, set bits or set all
2485 * @p: pointer to desired bits
2487 * Set the modem status bits from the tty driver if the feature
2488 * is supported. Return -EINVAL if it is not available.
2490 * Locking: none (up to the driver)
2493 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2497 unsigned int set, clear, val;
2499 if (tty->ops->tiocmset == NULL)
2502 retval = get_user(val, p);
2518 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2519 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2520 return tty->ops->tiocmset(tty, set, clear);
2523 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2525 int retval = -EINVAL;
2526 struct serial_icounter_struct icount;
2527 memset(&icount, 0, sizeof(icount));
2528 if (tty->ops->get_icount)
2529 retval = tty->ops->get_icount(tty, &icount);
2532 if (copy_to_user(arg, &icount, sizeof(icount)))
2537 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2539 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2540 tty->driver->subtype == PTY_TYPE_MASTER)
2544 EXPORT_SYMBOL(tty_pair_get_tty);
2546 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2548 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2549 tty->driver->subtype == PTY_TYPE_MASTER)
2553 EXPORT_SYMBOL(tty_pair_get_pty);
2556 * Split this up, as gcc can choke on it otherwise..
2558 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2560 struct tty_struct *tty = file_tty(file);
2561 struct tty_struct *real_tty;
2562 void __user *p = (void __user *)arg;
2564 struct tty_ldisc *ld;
2565 struct inode *inode = file->f_dentry->d_inode;
2567 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2570 real_tty = tty_pair_get_tty(tty);
2573 * Factor out some common prep work
2581 retval = tty_check_change(tty);
2584 if (cmd != TIOCCBRK) {
2585 tty_wait_until_sent(tty, 0);
2586 if (signal_pending(current))
2597 return tiocsti(tty, p);
2599 return tiocgwinsz(real_tty, p);
2601 return tiocswinsz(real_tty, p);
2603 return real_tty != tty ? -EINVAL : tioccons(file);
2605 return fionbio(file, p);
2607 set_bit(TTY_EXCLUSIVE, &tty->flags);
2610 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2613 if (current->signal->tty != tty)
2618 return tiocsctty(tty, arg);
2620 return tiocgpgrp(tty, real_tty, p);
2622 return tiocspgrp(tty, real_tty, p);
2624 return tiocgsid(tty, real_tty, p);
2626 return put_user(tty->ldisc->ops->num, (int __user *)p);
2628 return tiocsetd(tty, p);
2630 if (!capable(CAP_SYS_ADMIN))
2636 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2637 return put_user(ret, (unsigned int __user *)p);
2642 case TIOCSBRK: /* Turn break on, unconditionally */
2643 if (tty->ops->break_ctl)
2644 return tty->ops->break_ctl(tty, -1);
2646 case TIOCCBRK: /* Turn break off, unconditionally */
2647 if (tty->ops->break_ctl)
2648 return tty->ops->break_ctl(tty, 0);
2650 case TCSBRK: /* SVID version: non-zero arg --> no break */
2651 /* non-zero arg means wait for all output data
2652 * to be sent (performed above) but don't send break.
2653 * This is used by the tcdrain() termios function.
2656 return send_break(tty, 250);
2658 case TCSBRKP: /* support for POSIX tcsendbreak() */
2659 return send_break(tty, arg ? arg*100 : 250);
2662 return tty_tiocmget(tty, p);
2666 return tty_tiocmset(tty, cmd, p);
2668 retval = tty_tiocgicount(tty, p);
2669 /* For the moment allow fall through to the old method */
2670 if (retval != -EINVAL)
2677 /* flush tty buffer and allow ldisc to process ioctl */
2678 tty_buffer_flush(tty);
2683 if (tty->ops->ioctl) {
2684 retval = (tty->ops->ioctl)(tty, cmd, arg);
2685 if (retval != -ENOIOCTLCMD)
2688 ld = tty_ldisc_ref_wait(tty);
2690 if (ld->ops->ioctl) {
2691 retval = ld->ops->ioctl(tty, file, cmd, arg);
2692 if (retval == -ENOIOCTLCMD)
2695 tty_ldisc_deref(ld);
2699 #ifdef CONFIG_COMPAT
2700 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2703 struct inode *inode = file->f_dentry->d_inode;
2704 struct tty_struct *tty = file_tty(file);
2705 struct tty_ldisc *ld;
2706 int retval = -ENOIOCTLCMD;
2708 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2711 if (tty->ops->compat_ioctl) {
2712 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2713 if (retval != -ENOIOCTLCMD)
2717 ld = tty_ldisc_ref_wait(tty);
2718 if (ld->ops->compat_ioctl)
2719 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2720 tty_ldisc_deref(ld);
2727 * This implements the "Secure Attention Key" --- the idea is to
2728 * prevent trojan horses by killing all processes associated with this
2729 * tty when the user hits the "Secure Attention Key". Required for
2730 * super-paranoid applications --- see the Orange Book for more details.
2732 * This code could be nicer; ideally it should send a HUP, wait a few
2733 * seconds, then send a INT, and then a KILL signal. But you then
2734 * have to coordinate with the init process, since all processes associated
2735 * with the current tty must be dead before the new getty is allowed
2738 * Now, if it would be correct ;-/ The current code has a nasty hole -
2739 * it doesn't catch files in flight. We may send the descriptor to ourselves
2740 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2742 * Nasty bug: do_SAK is being called in interrupt context. This can
2743 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2745 void __do_SAK(struct tty_struct *tty)
2750 struct task_struct *g, *p;
2751 struct pid *session;
2754 struct fdtable *fdt;
2758 session = tty->session;
2760 tty_ldisc_flush(tty);
2762 tty_driver_flush_buffer(tty);
2764 read_lock(&tasklist_lock);
2765 /* Kill the entire session */
2766 do_each_pid_task(session, PIDTYPE_SID, p) {
2767 printk(KERN_NOTICE "SAK: killed process %d"
2768 " (%s): task_session(p)==tty->session\n",
2769 task_pid_nr(p), p->comm);
2770 send_sig(SIGKILL, p, 1);
2771 } while_each_pid_task(session, PIDTYPE_SID, p);
2772 /* Now kill any processes that happen to have the
2775 do_each_thread(g, p) {
2776 if (p->signal->tty == tty) {
2777 printk(KERN_NOTICE "SAK: killed process %d"
2778 " (%s): task_session(p)==tty->session\n",
2779 task_pid_nr(p), p->comm);
2780 send_sig(SIGKILL, p, 1);
2786 * We don't take a ref to the file, so we must
2787 * hold ->file_lock instead.
2789 spin_lock(&p->files->file_lock);
2790 fdt = files_fdtable(p->files);
2791 for (i = 0; i < fdt->max_fds; i++) {
2792 filp = fcheck_files(p->files, i);
2795 if (filp->f_op->read == tty_read &&
2796 file_tty(filp) == tty) {
2797 printk(KERN_NOTICE "SAK: killed process %d"
2798 " (%s): fd#%d opened to the tty\n",
2799 task_pid_nr(p), p->comm, i);
2800 force_sig(SIGKILL, p);
2804 spin_unlock(&p->files->file_lock);
2807 } while_each_thread(g, p);
2808 read_unlock(&tasklist_lock);
2812 static void do_SAK_work(struct work_struct *work)
2814 struct tty_struct *tty =
2815 container_of(work, struct tty_struct, SAK_work);
2820 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2821 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2822 * the values which we write to it will be identical to the values which it
2823 * already has. --akpm
2825 void do_SAK(struct tty_struct *tty)
2829 schedule_work(&tty->SAK_work);
2832 EXPORT_SYMBOL(do_SAK);
2834 static int dev_match_devt(struct device *dev, void *data)
2837 return dev->devt == *devt;
2840 /* Must put_device() after it's unused! */
2841 static struct device *tty_get_device(struct tty_struct *tty)
2843 dev_t devt = tty_devnum(tty);
2844 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2849 * initialize_tty_struct
2850 * @tty: tty to initialize
2852 * This subroutine initializes a tty structure that has been newly
2855 * Locking: none - tty in question must not be exposed at this point
2858 void initialize_tty_struct(struct tty_struct *tty,
2859 struct tty_driver *driver, int idx)
2861 memset(tty, 0, sizeof(struct tty_struct));
2862 kref_init(&tty->kref);
2863 tty->magic = TTY_MAGIC;
2864 tty_ldisc_init(tty);
2865 tty->session = NULL;
2867 tty->overrun_time = jiffies;
2868 tty->buf.head = tty->buf.tail = NULL;
2869 tty_buffer_init(tty);
2870 mutex_init(&tty->termios_mutex);
2871 mutex_init(&tty->ldisc_mutex);
2872 init_waitqueue_head(&tty->write_wait);
2873 init_waitqueue_head(&tty->read_wait);
2874 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2875 mutex_init(&tty->atomic_read_lock);
2876 mutex_init(&tty->atomic_write_lock);
2877 mutex_init(&tty->output_lock);
2878 mutex_init(&tty->echo_lock);
2879 spin_lock_init(&tty->read_lock);
2880 spin_lock_init(&tty->ctrl_lock);
2881 INIT_LIST_HEAD(&tty->tty_files);
2882 INIT_WORK(&tty->SAK_work, do_SAK_work);
2884 tty->driver = driver;
2885 tty->ops = driver->ops;
2887 tty_line_name(driver, idx, tty->name);
2888 tty->dev = tty_get_device(tty);
2892 * deinitialize_tty_struct
2893 * @tty: tty to deinitialize
2895 * This subroutine deinitializes a tty structure that has been newly
2896 * allocated but tty_release cannot be called on that yet.
2898 * Locking: none - tty in question must not be exposed at this point
2900 void deinitialize_tty_struct(struct tty_struct *tty)
2902 tty_ldisc_deinit(tty);
2906 * tty_put_char - write one character to a tty
2910 * Write one byte to the tty using the provided put_char method
2911 * if present. Returns the number of characters successfully output.
2913 * Note: the specific put_char operation in the driver layer may go
2914 * away soon. Don't call it directly, use this method
2917 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2919 if (tty->ops->put_char)
2920 return tty->ops->put_char(tty, ch);
2921 return tty->ops->write(tty, &ch, 1);
2923 EXPORT_SYMBOL_GPL(tty_put_char);
2925 struct class *tty_class;
2928 * tty_register_device - register a tty device
2929 * @driver: the tty driver that describes the tty device
2930 * @index: the index in the tty driver for this tty device
2931 * @device: a struct device that is associated with this tty device.
2932 * This field is optional, if there is no known struct device
2933 * for this tty device it can be set to NULL safely.
2935 * Returns a pointer to the struct device for this tty device
2936 * (or ERR_PTR(-EFOO) on error).
2938 * This call is required to be made to register an individual tty device
2939 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2940 * that bit is not set, this function should not be called by a tty
2946 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2947 struct device *device)
2950 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2952 if (index >= driver->num) {
2953 printk(KERN_ERR "Attempt to register invalid tty line number "
2955 return ERR_PTR(-EINVAL);
2958 if (driver->type == TTY_DRIVER_TYPE_PTY)
2959 pty_line_name(driver, index, name);
2961 tty_line_name(driver, index, name);
2963 return device_create(tty_class, device, dev, NULL, name);
2965 EXPORT_SYMBOL(tty_register_device);
2968 * tty_unregister_device - unregister a tty device
2969 * @driver: the tty driver that describes the tty device
2970 * @index: the index in the tty driver for this tty device
2972 * If a tty device is registered with a call to tty_register_device() then
2973 * this function must be called when the tty device is gone.
2978 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2980 device_destroy(tty_class,
2981 MKDEV(driver->major, driver->minor_start) + index);
2983 EXPORT_SYMBOL(tty_unregister_device);
2985 struct tty_driver *alloc_tty_driver(int lines)
2987 struct tty_driver *driver;
2989 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2991 kref_init(&driver->kref);
2992 driver->magic = TTY_DRIVER_MAGIC;
2993 driver->num = lines;
2994 /* later we'll move allocation of tables here */
2998 EXPORT_SYMBOL(alloc_tty_driver);
3000 static void destruct_tty_driver(struct kref *kref)
3002 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3004 struct ktermios *tp;
3007 if (driver->flags & TTY_DRIVER_INSTALLED) {
3009 * Free the termios and termios_locked structures because
3010 * we don't want to get memory leaks when modular tty
3011 * drivers are removed from the kernel.
3013 for (i = 0; i < driver->num; i++) {
3014 tp = driver->termios[i];
3016 driver->termios[i] = NULL;
3019 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3020 tty_unregister_device(driver, i);
3023 proc_tty_unregister_driver(driver);
3024 driver->ttys = NULL;
3025 driver->termios = NULL;
3027 cdev_del(&driver->cdev);
3032 void tty_driver_kref_put(struct tty_driver *driver)
3034 kref_put(&driver->kref, destruct_tty_driver);
3036 EXPORT_SYMBOL(tty_driver_kref_put);
3038 void tty_set_operations(struct tty_driver *driver,
3039 const struct tty_operations *op)
3043 EXPORT_SYMBOL(tty_set_operations);
3045 void put_tty_driver(struct tty_driver *d)
3047 tty_driver_kref_put(d);
3049 EXPORT_SYMBOL(put_tty_driver);
3052 * Called by a tty driver to register itself.
3054 int tty_register_driver(struct tty_driver *driver)
3062 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3063 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3068 if (!driver->major) {
3069 error = alloc_chrdev_region(&dev, driver->minor_start,
3070 driver->num, driver->name);
3072 driver->major = MAJOR(dev);
3073 driver->minor_start = MINOR(dev);
3076 dev = MKDEV(driver->major, driver->minor_start);
3077 error = register_chrdev_region(dev, driver->num, driver->name);
3085 driver->ttys = (struct tty_struct **)p;
3086 driver->termios = (struct ktermios **)(p + driver->num);
3088 driver->ttys = NULL;
3089 driver->termios = NULL;
3092 cdev_init(&driver->cdev, &tty_fops);
3093 driver->cdev.owner = driver->owner;
3094 error = cdev_add(&driver->cdev, dev, driver->num);
3096 unregister_chrdev_region(dev, driver->num);
3097 driver->ttys = NULL;
3098 driver->termios = NULL;
3103 mutex_lock(&tty_mutex);
3104 list_add(&driver->tty_drivers, &tty_drivers);
3105 mutex_unlock(&tty_mutex);
3107 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3108 for (i = 0; i < driver->num; i++) {
3109 d = tty_register_device(driver, i, NULL);
3116 proc_tty_register_driver(driver);
3117 driver->flags |= TTY_DRIVER_INSTALLED;
3121 for (i--; i >= 0; i--)
3122 tty_unregister_device(driver, i);
3124 mutex_lock(&tty_mutex);
3125 list_del(&driver->tty_drivers);
3126 mutex_unlock(&tty_mutex);
3128 unregister_chrdev_region(dev, driver->num);
3129 driver->ttys = NULL;
3130 driver->termios = NULL;
3135 EXPORT_SYMBOL(tty_register_driver);
3138 * Called by a tty driver to unregister itself.
3140 int tty_unregister_driver(struct tty_driver *driver)
3144 if (driver->refcount)
3147 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3149 mutex_lock(&tty_mutex);
3150 list_del(&driver->tty_drivers);
3151 mutex_unlock(&tty_mutex);
3155 EXPORT_SYMBOL(tty_unregister_driver);
3157 dev_t tty_devnum(struct tty_struct *tty)
3159 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3161 EXPORT_SYMBOL(tty_devnum);
3163 void proc_clear_tty(struct task_struct *p)
3165 unsigned long flags;
3166 struct tty_struct *tty;
3167 spin_lock_irqsave(&p->sighand->siglock, flags);
3168 tty = p->signal->tty;
3169 p->signal->tty = NULL;
3170 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3174 /* Called under the sighand lock */
3176 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3179 unsigned long flags;
3180 /* We should not have a session or pgrp to put here but.... */
3181 spin_lock_irqsave(&tty->ctrl_lock, flags);
3182 put_pid(tty->session);
3184 tty->pgrp = get_pid(task_pgrp(tsk));
3185 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3186 tty->session = get_pid(task_session(tsk));
3187 if (tsk->signal->tty) {
3188 printk(KERN_DEBUG "tty not NULL!!\n");
3189 tty_kref_put(tsk->signal->tty);
3192 put_pid(tsk->signal->tty_old_pgrp);
3193 tsk->signal->tty = tty_kref_get(tty);
3194 tsk->signal->tty_old_pgrp = NULL;
3197 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3199 spin_lock_irq(&tsk->sighand->siglock);
3200 __proc_set_tty(tsk, tty);
3201 spin_unlock_irq(&tsk->sighand->siglock);
3204 struct tty_struct *get_current_tty(void)
3206 struct tty_struct *tty;
3207 unsigned long flags;
3209 spin_lock_irqsave(¤t->sighand->siglock, flags);
3210 tty = tty_kref_get(current->signal->tty);
3211 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3214 EXPORT_SYMBOL_GPL(get_current_tty);
3216 void tty_default_fops(struct file_operations *fops)
3222 * Initialize the console device. This is called *early*, so
3223 * we can't necessarily depend on lots of kernel help here.
3224 * Just do some early initializations, and do the complex setup
3227 void __init console_init(void)
3231 /* Setup the default TTY line discipline. */
3235 * set up the console device so that later boot sequences can
3236 * inform about problems etc..
3238 call = __con_initcall_start;
3239 while (call < __con_initcall_end) {
3245 static char *tty_devnode(struct device *dev, mode_t *mode)
3249 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3250 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3255 static int __init tty_class_init(void)
3257 tty_class = class_create(THIS_MODULE, "tty");
3258 if (IS_ERR(tty_class))
3259 return PTR_ERR(tty_class);
3260 tty_class->devnode = tty_devnode;
3264 postcore_initcall(tty_class_init);
3266 /* 3/2004 jmc: why do these devices exist? */
3267 static struct cdev tty_cdev, console_cdev;
3269 static ssize_t show_cons_active(struct device *dev,
3270 struct device_attribute *attr, char *buf)
3272 struct console *cs[16];
3278 for_each_console(c) {
3283 if ((c->flags & CON_ENABLED) == 0)
3286 if (i >= ARRAY_SIZE(cs))
3290 count += sprintf(buf + count, "%s%d%c",
3291 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3296 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3298 static struct device *consdev;
3300 void console_sysfs_notify(void)
3303 sysfs_notify(&consdev->kobj, NULL, "active");
3307 * Ok, now we can initialize the rest of the tty devices and can count
3308 * on memory allocations, interrupts etc..
3310 int __init tty_init(void)
3312 cdev_init(&tty_cdev, &tty_fops);
3313 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3314 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3315 panic("Couldn't register /dev/tty driver\n");
3316 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3318 cdev_init(&console_cdev, &console_fops);
3319 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3320 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3321 panic("Couldn't register /dev/console driver\n");
3322 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3324 if (IS_ERR(consdev))
3327 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3330 vty_init(&console_fops);