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>
98 #include <linux/uaccess.h>
99 #include <asm/system.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
114 .c_iflag = ICRNL | IXON,
115 .c_oflag = OPOST | ONLCR,
116 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
117 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
118 ECHOCTL | ECHOKE | IEXTEN,
124 EXPORT_SYMBOL(tty_std_termios);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex);
135 EXPORT_SYMBOL(tty_mutex);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock);
140 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
141 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
142 ssize_t redirected_tty_write(struct file *, const char __user *,
144 static unsigned int tty_poll(struct file *, poll_table *);
145 static int tty_open(struct inode *, struct file *);
146 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
148 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd, struct file *filp, int on);
154 static int tty_fasync(int fd, struct file *filp, int on);
155 static void release_tty(struct tty_struct *tty, int idx);
156 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
157 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
160 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct *alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct *tty)
185 put_device(tty->dev);
186 kfree(tty->write_buf);
187 tty_buffer_free_all(tty);
191 static inline struct tty_struct *file_tty(struct file *file)
193 return ((struct tty_file_private *)file->private_data)->tty;
196 /* Associate a new file with the tty structure */
197 int tty_add_file(struct tty_struct *tty, struct file *file)
199 struct tty_file_private *priv;
201 priv = kmalloc(sizeof(*priv), GFP_KERNEL);
207 file->private_data = priv;
209 spin_lock(&tty_files_lock);
210 list_add(&priv->list, &tty->tty_files);
211 spin_unlock(&tty_files_lock);
216 /* Delete file from its tty */
217 void tty_del_file(struct file *file)
219 struct tty_file_private *priv = file->private_data;
221 spin_lock(&tty_files_lock);
222 list_del(&priv->list);
223 spin_unlock(&tty_files_lock);
224 file->private_data = NULL;
229 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
232 * tty_name - return tty naming
233 * @tty: tty structure
234 * @buf: buffer for output
236 * Convert a tty structure into a name. The name reflects the kernel
237 * naming policy and if udev is in use may not reflect user space
242 char *tty_name(struct tty_struct *tty, char *buf)
244 if (!tty) /* Hmm. NULL pointer. That's fun. */
245 strcpy(buf, "NULL tty");
247 strcpy(buf, tty->name);
251 EXPORT_SYMBOL(tty_name);
253 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
256 #ifdef TTY_PARANOIA_CHECK
259 "null TTY for (%d:%d) in %s\n",
260 imajor(inode), iminor(inode), routine);
263 if (tty->magic != TTY_MAGIC) {
265 "bad magic number for tty struct (%d:%d) in %s\n",
266 imajor(inode), iminor(inode), routine);
273 static int check_tty_count(struct tty_struct *tty, const char *routine)
275 #ifdef CHECK_TTY_COUNT
279 spin_lock(&tty_files_lock);
280 list_for_each(p, &tty->tty_files) {
283 spin_unlock(&tty_files_lock);
284 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
285 tty->driver->subtype == PTY_TYPE_SLAVE &&
286 tty->link && tty->link->count)
288 if (tty->count != count) {
289 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
290 "!= #fd's(%d) in %s\n",
291 tty->name, tty->count, count, routine);
299 * get_tty_driver - find device of a tty
300 * @dev_t: device identifier
301 * @index: returns the index of the tty
303 * This routine returns a tty driver structure, given a device number
304 * and also passes back the index number.
306 * Locking: caller must hold tty_mutex
309 static struct tty_driver *get_tty_driver(dev_t device, int *index)
311 struct tty_driver *p;
313 list_for_each_entry(p, &tty_drivers, tty_drivers) {
314 dev_t base = MKDEV(p->major, p->minor_start);
315 if (device < base || device >= base + p->num)
317 *index = device - base;
318 return tty_driver_kref_get(p);
323 #ifdef CONFIG_CONSOLE_POLL
326 * tty_find_polling_driver - find device of a polled tty
327 * @name: name string to match
328 * @line: pointer to resulting tty line nr
330 * This routine returns a tty driver structure, given a name
331 * and the condition that the tty driver is capable of polled
334 struct tty_driver *tty_find_polling_driver(char *name, int *line)
336 struct tty_driver *p, *res = NULL;
341 for (str = name; *str; str++)
342 if ((*str >= '0' && *str <= '9') || *str == ',')
348 tty_line = simple_strtoul(str, &str, 10);
350 mutex_lock(&tty_mutex);
351 /* Search through the tty devices to look for a match */
352 list_for_each_entry(p, &tty_drivers, tty_drivers) {
353 if (strncmp(name, p->name, len) != 0)
361 if (tty_line >= 0 && tty_line < p->num && p->ops &&
362 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
363 res = tty_driver_kref_get(p);
368 mutex_unlock(&tty_mutex);
372 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
376 * tty_check_change - check for POSIX terminal changes
379 * If we try to write to, or set the state of, a terminal and we're
380 * not in the foreground, send a SIGTTOU. If the signal is blocked or
381 * ignored, go ahead and perform the operation. (POSIX 7.2)
386 int tty_check_change(struct tty_struct *tty)
391 if (current->signal->tty != tty)
394 spin_lock_irqsave(&tty->ctrl_lock, flags);
397 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
400 if (task_pgrp(current) == tty->pgrp)
402 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
403 if (is_ignored(SIGTTOU))
405 if (is_current_pgrp_orphaned()) {
409 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
410 set_thread_flag(TIF_SIGPENDING);
415 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
419 EXPORT_SYMBOL(tty_check_change);
421 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
422 size_t count, loff_t *ppos)
427 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
428 size_t count, loff_t *ppos)
433 /* No kernel lock held - none needed ;) */
434 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
436 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
439 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
442 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
445 static long hung_up_tty_compat_ioctl(struct file *file,
446 unsigned int cmd, unsigned long arg)
448 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
451 static const struct file_operations tty_fops = {
456 .unlocked_ioctl = tty_ioctl,
457 .compat_ioctl = tty_compat_ioctl,
459 .release = tty_release,
460 .fasync = tty_fasync,
463 static const struct file_operations console_fops = {
466 .write = redirected_tty_write,
468 .unlocked_ioctl = tty_ioctl,
469 .compat_ioctl = tty_compat_ioctl,
471 .release = tty_release,
472 .fasync = tty_fasync,
475 static const struct file_operations hung_up_tty_fops = {
477 .read = hung_up_tty_read,
478 .write = hung_up_tty_write,
479 .poll = hung_up_tty_poll,
480 .unlocked_ioctl = hung_up_tty_ioctl,
481 .compat_ioctl = hung_up_tty_compat_ioctl,
482 .release = tty_release,
485 static DEFINE_SPINLOCK(redirect_lock);
486 static struct file *redirect;
489 * tty_wakeup - request more data
492 * Internal and external helper for wakeups of tty. This function
493 * informs the line discipline if present that the driver is ready
494 * to receive more output data.
497 void tty_wakeup(struct tty_struct *tty)
499 struct tty_ldisc *ld;
501 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
502 ld = tty_ldisc_ref(tty);
504 if (ld->ops->write_wakeup)
505 ld->ops->write_wakeup(tty);
509 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
512 EXPORT_SYMBOL_GPL(tty_wakeup);
515 * __tty_hangup - actual handler for hangup events
518 * This can be called by the "eventd" kernel thread. That is process
519 * synchronous but doesn't hold any locks, so we need to make sure we
520 * have the appropriate locks for what we're doing.
522 * The hangup event clears any pending redirections onto the hung up
523 * device. It ensures future writes will error and it does the needed
524 * line discipline hangup and signal delivery. The tty object itself
529 * redirect lock for undoing redirection
530 * file list lock for manipulating list of ttys
531 * tty_ldisc_lock from called functions
532 * termios_mutex resetting termios data
533 * tasklist_lock to walk task list for hangup event
534 * ->siglock to protect ->signal/->sighand
536 void __tty_hangup(struct tty_struct *tty)
538 struct file *cons_filp = NULL;
539 struct file *filp, *f = NULL;
540 struct task_struct *p;
541 struct tty_file_private *priv;
542 int closecount = 0, n;
550 spin_lock(&redirect_lock);
551 if (redirect && file_tty(redirect) == tty) {
555 spin_unlock(&redirect_lock);
559 /* some functions below drop BTM, so we need this bit */
560 set_bit(TTY_HUPPING, &tty->flags);
562 /* inuse_filps is protected by the single tty lock,
563 this really needs to change if we want to flush the
564 workqueue with the lock held */
565 check_tty_count(tty, "tty_hangup");
567 spin_lock(&tty_files_lock);
568 /* This breaks for file handles being sent over AF_UNIX sockets ? */
569 list_for_each_entry(priv, &tty->tty_files, list) {
571 if (filp->f_op->write == redirected_tty_write)
573 if (filp->f_op->write != tty_write)
576 __tty_fasync(-1, filp, 0); /* can't block */
577 filp->f_op = &hung_up_tty_fops;
579 spin_unlock(&tty_files_lock);
582 * it drops BTM and thus races with reopen
583 * we protect the race by TTY_HUPPING
585 tty_ldisc_hangup(tty);
587 read_lock(&tasklist_lock);
589 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
590 spin_lock_irq(&p->sighand->siglock);
591 if (p->signal->tty == tty) {
592 p->signal->tty = NULL;
593 /* We defer the dereferences outside fo
597 if (!p->signal->leader) {
598 spin_unlock_irq(&p->sighand->siglock);
601 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
602 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
603 put_pid(p->signal->tty_old_pgrp); /* A noop */
604 spin_lock_irqsave(&tty->ctrl_lock, flags);
606 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
607 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
608 spin_unlock_irq(&p->sighand->siglock);
609 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
611 read_unlock(&tasklist_lock);
613 spin_lock_irqsave(&tty->ctrl_lock, flags);
614 clear_bit(TTY_THROTTLED, &tty->flags);
615 clear_bit(TTY_PUSH, &tty->flags);
616 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
617 put_pid(tty->session);
621 tty->ctrl_status = 0;
622 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
624 /* Account for the p->signal references we killed */
629 * If one of the devices matches a console pointer, we
630 * cannot just call hangup() because that will cause
631 * tty->count and state->count to go out of sync.
632 * So we just call close() the right number of times.
636 for (n = 0; n < closecount; n++)
637 tty->ops->close(tty, cons_filp);
638 } else if (tty->ops->hangup)
639 (tty->ops->hangup)(tty);
641 * We don't want to have driver/ldisc interactions beyond
642 * the ones we did here. The driver layer expects no
643 * calls after ->hangup() from the ldisc side. However we
644 * can't yet guarantee all that.
646 set_bit(TTY_HUPPED, &tty->flags);
647 clear_bit(TTY_HUPPING, &tty->flags);
648 tty_ldisc_enable(tty);
656 static void do_tty_hangup(struct work_struct *work)
658 struct tty_struct *tty =
659 container_of(work, struct tty_struct, hangup_work);
665 * tty_hangup - trigger a hangup event
666 * @tty: tty to hangup
668 * A carrier loss (virtual or otherwise) has occurred on this like
669 * schedule a hangup sequence to run after this event.
672 void tty_hangup(struct tty_struct *tty)
674 #ifdef TTY_DEBUG_HANGUP
676 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
678 schedule_work(&tty->hangup_work);
681 EXPORT_SYMBOL(tty_hangup);
684 * tty_vhangup - process vhangup
685 * @tty: tty to hangup
687 * The user has asked via system call for the terminal to be hung up.
688 * We do this synchronously so that when the syscall returns the process
689 * is complete. That guarantee is necessary for security reasons.
692 void tty_vhangup(struct tty_struct *tty)
694 #ifdef TTY_DEBUG_HANGUP
697 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
702 EXPORT_SYMBOL(tty_vhangup);
706 * tty_vhangup_self - process vhangup for own ctty
708 * Perform a vhangup on the current controlling tty
711 void tty_vhangup_self(void)
713 struct tty_struct *tty;
715 tty = get_current_tty();
723 * tty_hung_up_p - was tty hung up
724 * @filp: file pointer of tty
726 * Return true if the tty has been subject to a vhangup or a carrier
730 int tty_hung_up_p(struct file *filp)
732 return (filp->f_op == &hung_up_tty_fops);
735 EXPORT_SYMBOL(tty_hung_up_p);
737 static void session_clear_tty(struct pid *session)
739 struct task_struct *p;
740 do_each_pid_task(session, PIDTYPE_SID, p) {
742 } while_each_pid_task(session, PIDTYPE_SID, p);
746 * disassociate_ctty - disconnect controlling tty
747 * @on_exit: true if exiting so need to "hang up" the session
749 * This function is typically called only by the session leader, when
750 * it wants to disassociate itself from its controlling tty.
752 * It performs the following functions:
753 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
754 * (2) Clears the tty from being controlling the session
755 * (3) Clears the controlling tty for all processes in the
758 * The argument on_exit is set to 1 if called when a process is
759 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
762 * BTM is taken for hysterical raisins, and held when
763 * called from no_tty().
764 * tty_mutex is taken to protect tty
765 * ->siglock is taken to protect ->signal/->sighand
766 * tasklist_lock is taken to walk process list for sessions
767 * ->siglock is taken to protect ->signal/->sighand
770 void disassociate_ctty(int on_exit)
772 struct tty_struct *tty;
773 struct pid *tty_pgrp = NULL;
775 if (!current->signal->leader)
778 tty = get_current_tty();
780 tty_pgrp = get_pid(tty->pgrp);
782 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
786 } else if (on_exit) {
787 struct pid *old_pgrp;
788 spin_lock_irq(¤t->sighand->siglock);
789 old_pgrp = current->signal->tty_old_pgrp;
790 current->signal->tty_old_pgrp = NULL;
791 spin_unlock_irq(¤t->sighand->siglock);
793 kill_pgrp(old_pgrp, SIGHUP, on_exit);
794 kill_pgrp(old_pgrp, SIGCONT, on_exit);
800 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
802 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
806 spin_lock_irq(¤t->sighand->siglock);
807 put_pid(current->signal->tty_old_pgrp);
808 current->signal->tty_old_pgrp = NULL;
809 spin_unlock_irq(¤t->sighand->siglock);
811 tty = get_current_tty();
814 spin_lock_irqsave(&tty->ctrl_lock, flags);
815 put_pid(tty->session);
819 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
822 #ifdef TTY_DEBUG_HANGUP
823 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
828 /* Now clear signal->tty under the lock */
829 read_lock(&tasklist_lock);
830 session_clear_tty(task_session(current));
831 read_unlock(&tasklist_lock);
836 * no_tty - Ensure the current process does not have a controlling tty
840 struct task_struct *tsk = current;
842 disassociate_ctty(0);
849 * stop_tty - propagate flow control
852 * Perform flow control to the driver. For PTY/TTY pairs we
853 * must also propagate the TIOCKPKT status. May be called
854 * on an already stopped device and will not re-call the driver
857 * This functionality is used by both the line disciplines for
858 * halting incoming flow and by the driver. It may therefore be
859 * called from any context, may be under the tty atomic_write_lock
863 * Uses the tty control lock internally
866 void stop_tty(struct tty_struct *tty)
869 spin_lock_irqsave(&tty->ctrl_lock, flags);
871 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
875 if (tty->link && tty->link->packet) {
876 tty->ctrl_status &= ~TIOCPKT_START;
877 tty->ctrl_status |= TIOCPKT_STOP;
878 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
880 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
882 (tty->ops->stop)(tty);
885 EXPORT_SYMBOL(stop_tty);
888 * start_tty - propagate flow control
891 * Start a tty that has been stopped if at all possible. Perform
892 * any necessary wakeups and propagate the TIOCPKT status. If this
893 * is the tty was previous stopped and is being started then the
894 * driver start method is invoked and the line discipline woken.
900 void start_tty(struct tty_struct *tty)
903 spin_lock_irqsave(&tty->ctrl_lock, flags);
904 if (!tty->stopped || tty->flow_stopped) {
905 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
909 if (tty->link && tty->link->packet) {
910 tty->ctrl_status &= ~TIOCPKT_STOP;
911 tty->ctrl_status |= TIOCPKT_START;
912 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
914 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
916 (tty->ops->start)(tty);
917 /* If we have a running line discipline it may need kicking */
921 EXPORT_SYMBOL(start_tty);
924 * tty_read - read method for tty device files
925 * @file: pointer to tty file
927 * @count: size of user buffer
930 * Perform the read system call function on this terminal device. Checks
931 * for hung up devices before calling the line discipline method.
934 * Locks the line discipline internally while needed. Multiple
935 * read calls may be outstanding in parallel.
938 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
942 struct inode *inode = file->f_path.dentry->d_inode;
943 struct tty_struct *tty = file_tty(file);
944 struct tty_ldisc *ld;
946 if (tty_paranoia_check(tty, inode, "tty_read"))
948 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
951 /* We want to wait for the line discipline to sort out in this
953 ld = tty_ldisc_ref_wait(tty);
955 i = (ld->ops->read)(tty, file, buf, count);
960 inode->i_atime = current_fs_time(inode->i_sb);
964 void tty_write_unlock(struct tty_struct *tty)
966 mutex_unlock(&tty->atomic_write_lock);
967 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
970 int tty_write_lock(struct tty_struct *tty, int ndelay)
972 if (!mutex_trylock(&tty->atomic_write_lock)) {
975 if (mutex_lock_interruptible(&tty->atomic_write_lock))
982 * Split writes up in sane blocksizes to avoid
983 * denial-of-service type attacks
985 static inline ssize_t do_tty_write(
986 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
987 struct tty_struct *tty,
989 const char __user *buf,
992 ssize_t ret, written = 0;
995 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
1000 * We chunk up writes into a temporary buffer. This
1001 * simplifies low-level drivers immensely, since they
1002 * don't have locking issues and user mode accesses.
1004 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1007 * The default chunk-size is 2kB, because the NTTY
1008 * layer has problems with bigger chunks. It will
1009 * claim to be able to handle more characters than
1012 * FIXME: This can probably go away now except that 64K chunks
1013 * are too likely to fail unless switched to vmalloc...
1016 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
1021 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1022 if (tty->write_cnt < chunk) {
1023 unsigned char *buf_chunk;
1028 buf_chunk = kmalloc(chunk, GFP_KERNEL);
1033 kfree(tty->write_buf);
1034 tty->write_cnt = chunk;
1035 tty->write_buf = buf_chunk;
1038 /* Do the write .. */
1040 size_t size = count;
1044 if (copy_from_user(tty->write_buf, buf, size))
1046 ret = write(tty, file, tty->write_buf, size);
1055 if (signal_pending(current))
1060 struct inode *inode = file->f_path.dentry->d_inode;
1061 inode->i_mtime = current_fs_time(inode->i_sb);
1065 tty_write_unlock(tty);
1070 * tty_write_message - write a message to a certain tty, not just the console.
1071 * @tty: the destination tty_struct
1072 * @msg: the message to write
1074 * This is used for messages that need to be redirected to a specific tty.
1075 * We don't put it into the syslog queue right now maybe in the future if
1078 * We must still hold the BTM and test the CLOSING flag for the moment.
1081 void tty_write_message(struct tty_struct *tty, char *msg)
1084 mutex_lock(&tty->atomic_write_lock);
1086 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1088 tty->ops->write(tty, msg, strlen(msg));
1091 tty_write_unlock(tty);
1098 * tty_write - write method for tty device file
1099 * @file: tty file pointer
1100 * @buf: user data to write
1101 * @count: bytes to write
1104 * Write data to a tty device via the line discipline.
1107 * Locks the line discipline as required
1108 * Writes to the tty driver are serialized by the atomic_write_lock
1109 * and are then processed in chunks to the device. The line discipline
1110 * write method will not be invoked in parallel for each device.
1113 static ssize_t tty_write(struct file *file, const char __user *buf,
1114 size_t count, loff_t *ppos)
1116 struct inode *inode = file->f_path.dentry->d_inode;
1117 struct tty_struct *tty = file_tty(file);
1118 struct tty_ldisc *ld;
1121 if (tty_paranoia_check(tty, inode, "tty_write"))
1123 if (!tty || !tty->ops->write ||
1124 (test_bit(TTY_IO_ERROR, &tty->flags)))
1126 /* Short term debug to catch buggy drivers */
1127 if (tty->ops->write_room == NULL)
1128 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1130 ld = tty_ldisc_ref_wait(tty);
1131 if (!ld->ops->write)
1134 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1135 tty_ldisc_deref(ld);
1139 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1140 size_t count, loff_t *ppos)
1142 struct file *p = NULL;
1144 spin_lock(&redirect_lock);
1149 spin_unlock(&redirect_lock);
1153 res = vfs_write(p, buf, count, &p->f_pos);
1157 return tty_write(file, buf, count, ppos);
1160 static char ptychar[] = "pqrstuvwxyzabcde";
1163 * pty_line_name - generate name for a pty
1164 * @driver: the tty driver in use
1165 * @index: the minor number
1166 * @p: output buffer of at least 6 bytes
1168 * Generate a name from a driver reference and write it to the output
1173 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1175 int i = index + driver->name_base;
1176 /* ->name is initialized to "ttyp", but "tty" is expected */
1177 sprintf(p, "%s%c%x",
1178 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1179 ptychar[i >> 4 & 0xf], i & 0xf);
1183 * tty_line_name - generate name for a tty
1184 * @driver: the tty driver in use
1185 * @index: the minor number
1186 * @p: output buffer of at least 7 bytes
1188 * Generate a name from a driver reference and write it to the output
1193 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1195 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1199 * tty_driver_lookup_tty() - find an existing tty, if any
1200 * @driver: the driver for the tty
1201 * @idx: the minor number
1203 * Return the tty, if found or ERR_PTR() otherwise.
1205 * Locking: tty_mutex must be held. If tty is found, the mutex must
1206 * be held until the 'fast-open' is also done. Will change once we
1207 * have refcounting in the driver and per driver locking
1209 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1210 struct inode *inode, int idx)
1212 struct tty_struct *tty;
1214 if (driver->ops->lookup)
1215 return driver->ops->lookup(driver, inode, idx);
1217 tty = driver->ttys[idx];
1222 * tty_init_termios - helper for termios setup
1223 * @tty: the tty to set up
1225 * Initialise the termios structures for this tty. Thus runs under
1226 * the tty_mutex currently so we can be relaxed about ordering.
1229 int tty_init_termios(struct tty_struct *tty)
1231 struct ktermios *tp;
1232 int idx = tty->index;
1234 tp = tty->driver->termios[idx];
1236 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1239 memcpy(tp, &tty->driver->init_termios,
1240 sizeof(struct ktermios));
1241 tty->driver->termios[idx] = tp;
1244 tty->termios_locked = tp + 1;
1246 /* Compatibility until drivers always set this */
1247 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1248 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1251 EXPORT_SYMBOL_GPL(tty_init_termios);
1254 * tty_driver_install_tty() - install a tty entry in the driver
1255 * @driver: the driver for the tty
1258 * Install a tty object into the driver tables. The tty->index field
1259 * will be set by the time this is called. This method is responsible
1260 * for ensuring any need additional structures are allocated and
1263 * Locking: tty_mutex for now
1265 static int tty_driver_install_tty(struct tty_driver *driver,
1266 struct tty_struct *tty)
1268 int idx = tty->index;
1271 if (driver->ops->install) {
1272 ret = driver->ops->install(driver, tty);
1276 if (tty_init_termios(tty) == 0) {
1277 tty_driver_kref_get(driver);
1279 driver->ttys[idx] = tty;
1286 * tty_driver_remove_tty() - remove a tty from the driver tables
1287 * @driver: the driver for the tty
1288 * @idx: the minor number
1290 * Remvoe a tty object from the driver tables. The tty->index field
1291 * will be set by the time this is called.
1293 * Locking: tty_mutex for now
1295 static void tty_driver_remove_tty(struct tty_driver *driver,
1296 struct tty_struct *tty)
1298 if (driver->ops->remove)
1299 driver->ops->remove(driver, tty);
1301 driver->ttys[tty->index] = NULL;
1305 * tty_reopen() - fast re-open of an open tty
1306 * @tty - the tty to open
1308 * Return 0 on success, -errno on error.
1310 * Locking: tty_mutex must be held from the time the tty was found
1311 * till this open completes.
1313 static int tty_reopen(struct tty_struct *tty)
1315 struct tty_driver *driver = tty->driver;
1317 if (test_bit(TTY_CLOSING, &tty->flags) ||
1318 test_bit(TTY_HUPPING, &tty->flags) ||
1319 test_bit(TTY_LDISC_CHANGING, &tty->flags))
1322 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1323 driver->subtype == PTY_TYPE_MASTER) {
1325 * special case for PTY masters: only one open permitted,
1326 * and the slave side open count is incremented as well.
1334 tty->driver = driver; /* N.B. why do this every time?? */
1336 mutex_lock(&tty->ldisc_mutex);
1337 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1338 mutex_unlock(&tty->ldisc_mutex);
1344 * tty_init_dev - initialise a tty device
1345 * @driver: tty driver we are opening a device on
1346 * @idx: device index
1347 * @ret_tty: returned tty structure
1348 * @first_ok: ok to open a new device (used by ptmx)
1350 * Prepare a tty device. This may not be a "new" clean device but
1351 * could also be an active device. The pty drivers require special
1352 * handling because of this.
1355 * The function is called under the tty_mutex, which
1356 * protects us from the tty struct or driver itself going away.
1358 * On exit the tty device has the line discipline attached and
1359 * a reference count of 1. If a pair was created for pty/tty use
1360 * and the other was a pty master then it too has a reference count of 1.
1362 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1363 * failed open. The new code protects the open with a mutex, so it's
1364 * really quite straightforward. The mutex locking can probably be
1365 * relaxed for the (most common) case of reopening a tty.
1368 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1371 struct tty_struct *tty;
1374 /* Check if pty master is being opened multiple times */
1375 if (driver->subtype == PTY_TYPE_MASTER &&
1376 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1377 return ERR_PTR(-EIO);
1381 * First time open is complex, especially for PTY devices.
1382 * This code guarantees that either everything succeeds and the
1383 * TTY is ready for operation, or else the table slots are vacated
1384 * and the allocated memory released. (Except that the termios
1385 * and locked termios may be retained.)
1388 if (!try_module_get(driver->owner))
1389 return ERR_PTR(-ENODEV);
1391 tty = alloc_tty_struct();
1394 goto err_module_put;
1396 initialize_tty_struct(tty, driver, idx);
1398 retval = tty_driver_install_tty(driver, tty);
1400 goto err_deinit_tty;
1403 * Structures all installed ... call the ldisc open routines.
1404 * If we fail here just call release_tty to clean up. No need
1405 * to decrement the use counts, as release_tty doesn't care.
1407 retval = tty_ldisc_setup(tty, tty->link);
1409 goto err_release_tty;
1413 deinitialize_tty_struct(tty);
1414 free_tty_struct(tty);
1416 module_put(driver->owner);
1417 return ERR_PTR(retval);
1419 /* call the tty release_tty routine to clean out this slot */
1421 if (printk_ratelimit())
1422 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1423 "clearing slot %d\n", idx);
1424 release_tty(tty, idx);
1425 return ERR_PTR(retval);
1428 void tty_free_termios(struct tty_struct *tty)
1430 struct ktermios *tp;
1431 int idx = tty->index;
1432 /* Kill this flag and push into drivers for locking etc */
1433 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1434 /* FIXME: Locking on ->termios array */
1436 tty->driver->termios[idx] = NULL;
1440 EXPORT_SYMBOL(tty_free_termios);
1442 void tty_shutdown(struct tty_struct *tty)
1444 tty_driver_remove_tty(tty->driver, tty);
1445 tty_free_termios(tty);
1447 EXPORT_SYMBOL(tty_shutdown);
1450 * release_one_tty - release tty structure memory
1451 * @kref: kref of tty we are obliterating
1453 * Releases memory associated with a tty structure, and clears out the
1454 * driver table slots. This function is called when a device is no longer
1455 * in use. It also gets called when setup of a device fails.
1458 * tty_mutex - sometimes only
1459 * takes the file list lock internally when working on the list
1460 * of ttys that the driver keeps.
1462 * This method gets called from a work queue so that the driver private
1463 * cleanup ops can sleep (needed for USB at least)
1465 static void release_one_tty(struct work_struct *work)
1467 struct tty_struct *tty =
1468 container_of(work, struct tty_struct, hangup_work);
1469 struct tty_driver *driver = tty->driver;
1471 if (tty->ops->cleanup)
1472 tty->ops->cleanup(tty);
1475 tty_driver_kref_put(driver);
1476 module_put(driver->owner);
1478 spin_lock(&tty_files_lock);
1479 list_del_init(&tty->tty_files);
1480 spin_unlock(&tty_files_lock);
1483 put_pid(tty->session);
1484 free_tty_struct(tty);
1487 static void queue_release_one_tty(struct kref *kref)
1489 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1491 if (tty->ops->shutdown)
1492 tty->ops->shutdown(tty);
1496 /* The hangup queue is now free so we can reuse it rather than
1497 waste a chunk of memory for each port */
1498 INIT_WORK(&tty->hangup_work, release_one_tty);
1499 schedule_work(&tty->hangup_work);
1503 * tty_kref_put - release a tty kref
1506 * Release a reference to a tty device and if need be let the kref
1507 * layer destruct the object for us
1510 void tty_kref_put(struct tty_struct *tty)
1513 kref_put(&tty->kref, queue_release_one_tty);
1515 EXPORT_SYMBOL(tty_kref_put);
1518 * release_tty - release tty structure memory
1520 * Release both @tty and a possible linked partner (think pty pair),
1521 * and decrement the refcount of the backing module.
1524 * tty_mutex - sometimes only
1525 * takes the file list lock internally when working on the list
1526 * of ttys that the driver keeps.
1527 * FIXME: should we require tty_mutex is held here ??
1530 static void release_tty(struct tty_struct *tty, int idx)
1532 /* This should always be true but check for the moment */
1533 WARN_ON(tty->index != idx);
1536 tty_kref_put(tty->link);
1541 * tty_release - vfs callback for close
1542 * @inode: inode of tty
1543 * @filp: file pointer for handle to tty
1545 * Called the last time each file handle is closed that references
1546 * this tty. There may however be several such references.
1549 * Takes bkl. See tty_release_dev
1551 * Even releasing the tty structures is a tricky business.. We have
1552 * to be very careful that the structures are all released at the
1553 * same time, as interrupts might otherwise get the wrong pointers.
1555 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1556 * lead to double frees or releasing memory still in use.
1559 int tty_release(struct inode *inode, struct file *filp)
1561 struct tty_struct *tty = file_tty(filp);
1562 struct tty_struct *o_tty;
1563 int pty_master, tty_closing, o_tty_closing, do_sleep;
1568 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1572 check_tty_count(tty, "tty_release_dev");
1574 __tty_fasync(-1, filp, 0);
1577 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1578 tty->driver->subtype == PTY_TYPE_MASTER);
1579 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1582 #ifdef TTY_PARANOIA_CHECK
1583 if (idx < 0 || idx >= tty->driver->num) {
1584 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1585 "free (%s)\n", tty->name);
1590 if (tty != tty->driver->ttys[idx]) {
1592 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1593 "for (%s)\n", idx, tty->name);
1596 if (tty->termios != tty->driver->termios[idx]) {
1598 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1606 #ifdef TTY_DEBUG_HANGUP
1607 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1608 tty_name(tty, buf), tty->count);
1611 #ifdef TTY_PARANOIA_CHECK
1612 if (tty->driver->other &&
1613 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1614 if (o_tty != tty->driver->other->ttys[idx]) {
1616 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1617 "not o_tty for (%s)\n",
1621 if (o_tty->termios != tty->driver->other->termios[idx]) {
1623 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1624 "not o_termios for (%s)\n",
1628 if (o_tty->link != tty) {
1630 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1635 if (tty->ops->close)
1636 tty->ops->close(tty, filp);
1640 * Sanity check: if tty->count is going to zero, there shouldn't be
1641 * any waiters on tty->read_wait or tty->write_wait. We test the
1642 * wait queues and kick everyone out _before_ actually starting to
1643 * close. This ensures that we won't block while releasing the tty
1646 * The test for the o_tty closing is necessary, since the master and
1647 * slave sides may close in any order. If the slave side closes out
1648 * first, its count will be one, since the master side holds an open.
1649 * Thus this test wouldn't be triggered at the time the slave closes,
1652 * Note that it's possible for the tty to be opened again while we're
1653 * flushing out waiters. By recalculating the closing flags before
1654 * each iteration we avoid any problems.
1657 /* Guard against races with tty->count changes elsewhere and
1658 opens on /dev/tty */
1660 mutex_lock(&tty_mutex);
1662 tty_closing = tty->count <= 1;
1663 o_tty_closing = o_tty &&
1664 (o_tty->count <= (pty_master ? 1 : 0));
1668 if (waitqueue_active(&tty->read_wait)) {
1669 wake_up_poll(&tty->read_wait, POLLIN);
1672 if (waitqueue_active(&tty->write_wait)) {
1673 wake_up_poll(&tty->write_wait, POLLOUT);
1677 if (o_tty_closing) {
1678 if (waitqueue_active(&o_tty->read_wait)) {
1679 wake_up_poll(&o_tty->read_wait, POLLIN);
1682 if (waitqueue_active(&o_tty->write_wait)) {
1683 wake_up_poll(&o_tty->write_wait, POLLOUT);
1690 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1691 "active!\n", tty_name(tty, buf));
1693 mutex_unlock(&tty_mutex);
1698 * The closing flags are now consistent with the open counts on
1699 * both sides, and we've completed the last operation that could
1700 * block, so it's safe to proceed with closing.
1703 if (--o_tty->count < 0) {
1704 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1706 o_tty->count, tty_name(o_tty, buf));
1710 if (--tty->count < 0) {
1711 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1712 tty->count, tty_name(tty, buf));
1717 * We've decremented tty->count, so we need to remove this file
1718 * descriptor off the tty->tty_files list; this serves two
1720 * - check_tty_count sees the correct number of file descriptors
1721 * associated with this tty.
1722 * - do_tty_hangup no longer sees this file descriptor as
1723 * something that needs to be handled for hangups.
1728 * Perform some housekeeping before deciding whether to return.
1730 * Set the TTY_CLOSING flag if this was the last open. In the
1731 * case of a pty we may have to wait around for the other side
1732 * to close, and TTY_CLOSING makes sure we can't be reopened.
1735 set_bit(TTY_CLOSING, &tty->flags);
1737 set_bit(TTY_CLOSING, &o_tty->flags);
1740 * If _either_ side is closing, make sure there aren't any
1741 * processes that still think tty or o_tty is their controlling
1744 if (tty_closing || o_tty_closing) {
1745 read_lock(&tasklist_lock);
1746 session_clear_tty(tty->session);
1748 session_clear_tty(o_tty->session);
1749 read_unlock(&tasklist_lock);
1752 mutex_unlock(&tty_mutex);
1754 /* check whether both sides are closing ... */
1755 if (!tty_closing || (o_tty && !o_tty_closing)) {
1760 #ifdef TTY_DEBUG_HANGUP
1761 printk(KERN_DEBUG "freeing tty structure...");
1764 * Ask the line discipline code to release its structures
1766 tty_ldisc_release(tty, o_tty);
1768 * The release_tty function takes care of the details of clearing
1769 * the slots and preserving the termios structure.
1771 release_tty(tty, idx);
1773 /* Make this pty number available for reallocation */
1775 devpts_kill_index(inode, idx);
1781 * tty_open - open a tty device
1782 * @inode: inode of device file
1783 * @filp: file pointer to tty
1785 * tty_open and tty_release keep up the tty count that contains the
1786 * number of opens done on a tty. We cannot use the inode-count, as
1787 * different inodes might point to the same tty.
1789 * Open-counting is needed for pty masters, as well as for keeping
1790 * track of serial lines: DTR is dropped when the last close happens.
1791 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1793 * The termios state of a pty is reset on first open so that
1794 * settings don't persist across reuse.
1796 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1797 * tty->count should protect the rest.
1798 * ->siglock protects ->signal/->sighand
1801 static int tty_open(struct inode *inode, struct file *filp)
1803 struct tty_struct *tty = NULL;
1805 struct tty_driver *driver;
1807 dev_t device = inode->i_rdev;
1808 unsigned saved_flags = filp->f_flags;
1810 nonseekable_open(inode, filp);
1813 noctty = filp->f_flags & O_NOCTTY;
1817 mutex_lock(&tty_mutex);
1820 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1821 tty = get_current_tty();
1824 mutex_unlock(&tty_mutex);
1827 driver = tty_driver_kref_get(tty->driver);
1829 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1831 /* FIXME: Should we take a driver reference ? */
1836 if (device == MKDEV(TTY_MAJOR, 0)) {
1837 extern struct tty_driver *console_driver;
1838 driver = tty_driver_kref_get(console_driver);
1844 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1845 struct tty_driver *console_driver = console_device(&index);
1846 if (console_driver) {
1847 driver = tty_driver_kref_get(console_driver);
1849 /* Don't let /dev/console block */
1850 filp->f_flags |= O_NONBLOCK;
1856 mutex_unlock(&tty_mutex);
1860 driver = get_tty_driver(device, &index);
1863 mutex_unlock(&tty_mutex);
1868 /* check whether we're reopening an existing tty */
1869 tty = tty_driver_lookup_tty(driver, inode, index);
1873 mutex_unlock(&tty_mutex);
1874 return PTR_ERR(tty);
1879 retval = tty_reopen(tty);
1881 tty = ERR_PTR(retval);
1883 tty = tty_init_dev(driver, index, 0);
1885 mutex_unlock(&tty_mutex);
1886 tty_driver_kref_put(driver);
1889 return PTR_ERR(tty);
1892 retval = tty_add_file(tty, filp);
1895 tty_release(inode, filp);
1899 check_tty_count(tty, "tty_open");
1900 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1901 tty->driver->subtype == PTY_TYPE_MASTER)
1903 #ifdef TTY_DEBUG_HANGUP
1904 printk(KERN_DEBUG "opening %s...", tty->name);
1907 retval = tty->ops->open(tty, filp);
1910 filp->f_flags = saved_flags;
1912 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1913 !capable(CAP_SYS_ADMIN))
1917 #ifdef TTY_DEBUG_HANGUP
1918 printk(KERN_DEBUG "error %d in opening %s...", retval,
1921 tty_unlock(); /* need to call tty_release without BTM */
1922 tty_release(inode, filp);
1923 if (retval != -ERESTARTSYS)
1926 if (signal_pending(current))
1931 * Need to reset f_op in case a hangup happened.
1934 if (filp->f_op == &hung_up_tty_fops)
1935 filp->f_op = &tty_fops;
1942 mutex_lock(&tty_mutex);
1944 spin_lock_irq(¤t->sighand->siglock);
1946 current->signal->leader &&
1947 !current->signal->tty &&
1948 tty->session == NULL)
1949 __proc_set_tty(current, tty);
1950 spin_unlock_irq(¤t->sighand->siglock);
1952 mutex_unlock(&tty_mutex);
1959 * tty_poll - check tty status
1960 * @filp: file being polled
1961 * @wait: poll wait structures to update
1963 * Call the line discipline polling method to obtain the poll
1964 * status of the device.
1966 * Locking: locks called line discipline but ldisc poll method
1967 * may be re-entered freely by other callers.
1970 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1972 struct tty_struct *tty = file_tty(filp);
1973 struct tty_ldisc *ld;
1976 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1979 ld = tty_ldisc_ref_wait(tty);
1981 ret = (ld->ops->poll)(tty, filp, wait);
1982 tty_ldisc_deref(ld);
1986 static int __tty_fasync(int fd, struct file *filp, int on)
1988 struct tty_struct *tty = file_tty(filp);
1989 unsigned long flags;
1992 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1995 retval = fasync_helper(fd, filp, on, &tty->fasync);
2002 if (!waitqueue_active(&tty->read_wait))
2003 tty->minimum_to_wake = 1;
2004 spin_lock_irqsave(&tty->ctrl_lock, flags);
2007 type = PIDTYPE_PGID;
2009 pid = task_pid(current);
2013 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2014 retval = __f_setown(filp, pid, type, 0);
2019 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
2020 tty->minimum_to_wake = N_TTY_BUF_SIZE;
2027 static int tty_fasync(int fd, struct file *filp, int on)
2031 retval = __tty_fasync(fd, filp, on);
2037 * tiocsti - fake input character
2038 * @tty: tty to fake input into
2039 * @p: pointer to character
2041 * Fake input to a tty device. Does the necessary locking and
2044 * FIXME: does not honour flow control ??
2047 * Called functions take tty_ldisc_lock
2048 * current->signal->tty check is safe without locks
2050 * FIXME: may race normal receive processing
2053 static int tiocsti(struct tty_struct *tty, char __user *p)
2056 struct tty_ldisc *ld;
2058 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2060 if (get_user(ch, p))
2062 tty_audit_tiocsti(tty, ch);
2063 ld = tty_ldisc_ref_wait(tty);
2064 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2065 tty_ldisc_deref(ld);
2070 * tiocgwinsz - implement window query ioctl
2072 * @arg: user buffer for result
2074 * Copies the kernel idea of the window size into the user buffer.
2076 * Locking: tty->termios_mutex is taken to ensure the winsize data
2080 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2084 mutex_lock(&tty->termios_mutex);
2085 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2086 mutex_unlock(&tty->termios_mutex);
2088 return err ? -EFAULT: 0;
2092 * tty_do_resize - resize event
2093 * @tty: tty being resized
2094 * @rows: rows (character)
2095 * @cols: cols (character)
2097 * Update the termios variables and send the necessary signals to
2098 * peform a terminal resize correctly
2101 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2104 unsigned long flags;
2107 mutex_lock(&tty->termios_mutex);
2108 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2110 /* Get the PID values and reference them so we can
2111 avoid holding the tty ctrl lock while sending signals */
2112 spin_lock_irqsave(&tty->ctrl_lock, flags);
2113 pgrp = get_pid(tty->pgrp);
2114 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2117 kill_pgrp(pgrp, SIGWINCH, 1);
2122 mutex_unlock(&tty->termios_mutex);
2127 * tiocswinsz - implement window size set ioctl
2128 * @tty; tty side of tty
2129 * @arg: user buffer for result
2131 * Copies the user idea of the window size to the kernel. Traditionally
2132 * this is just advisory information but for the Linux console it
2133 * actually has driver level meaning and triggers a VC resize.
2136 * Driver dependent. The default do_resize method takes the
2137 * tty termios mutex and ctrl_lock. The console takes its own lock
2138 * then calls into the default method.
2141 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2143 struct winsize tmp_ws;
2144 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2147 if (tty->ops->resize)
2148 return tty->ops->resize(tty, &tmp_ws);
2150 return tty_do_resize(tty, &tmp_ws);
2154 * tioccons - allow admin to move logical console
2155 * @file: the file to become console
2157 * Allow the administrator to move the redirected console device
2159 * Locking: uses redirect_lock to guard the redirect information
2162 static int tioccons(struct file *file)
2164 if (!capable(CAP_SYS_ADMIN))
2166 if (file->f_op->write == redirected_tty_write) {
2168 spin_lock(&redirect_lock);
2171 spin_unlock(&redirect_lock);
2176 spin_lock(&redirect_lock);
2178 spin_unlock(&redirect_lock);
2183 spin_unlock(&redirect_lock);
2188 * fionbio - non blocking ioctl
2189 * @file: file to set blocking value
2190 * @p: user parameter
2192 * Historical tty interfaces had a blocking control ioctl before
2193 * the generic functionality existed. This piece of history is preserved
2194 * in the expected tty API of posix OS's.
2196 * Locking: none, the open file handle ensures it won't go away.
2199 static int fionbio(struct file *file, int __user *p)
2203 if (get_user(nonblock, p))
2206 spin_lock(&file->f_lock);
2208 file->f_flags |= O_NONBLOCK;
2210 file->f_flags &= ~O_NONBLOCK;
2211 spin_unlock(&file->f_lock);
2216 * tiocsctty - set controlling tty
2217 * @tty: tty structure
2218 * @arg: user argument
2220 * This ioctl is used to manage job control. It permits a session
2221 * leader to set this tty as the controlling tty for the session.
2224 * Takes tty_mutex() to protect tty instance
2225 * Takes tasklist_lock internally to walk sessions
2226 * Takes ->siglock() when updating signal->tty
2229 static int tiocsctty(struct tty_struct *tty, int arg)
2232 if (current->signal->leader && (task_session(current) == tty->session))
2235 mutex_lock(&tty_mutex);
2237 * The process must be a session leader and
2238 * not have a controlling tty already.
2240 if (!current->signal->leader || current->signal->tty) {
2247 * This tty is already the controlling
2248 * tty for another session group!
2250 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2254 read_lock(&tasklist_lock);
2255 session_clear_tty(tty->session);
2256 read_unlock(&tasklist_lock);
2262 proc_set_tty(current, tty);
2264 mutex_unlock(&tty_mutex);
2269 * tty_get_pgrp - return a ref counted pgrp pid
2272 * Returns a refcounted instance of the pid struct for the process
2273 * group controlling the tty.
2276 struct pid *tty_get_pgrp(struct tty_struct *tty)
2278 unsigned long flags;
2281 spin_lock_irqsave(&tty->ctrl_lock, flags);
2282 pgrp = get_pid(tty->pgrp);
2283 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2287 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2290 * tiocgpgrp - get process group
2291 * @tty: tty passed by user
2292 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2295 * Obtain the process group of the tty. If there is no process group
2298 * Locking: none. Reference to current->signal->tty is safe.
2301 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2306 * (tty == real_tty) is a cheap way of
2307 * testing if the tty is NOT a master pty.
2309 if (tty == real_tty && current->signal->tty != real_tty)
2311 pid = tty_get_pgrp(real_tty);
2312 ret = put_user(pid_vnr(pid), p);
2318 * tiocspgrp - attempt to set process group
2319 * @tty: tty passed by user
2320 * @real_tty: tty side device matching tty passed by user
2323 * Set the process group of the tty to the session passed. Only
2324 * permitted where the tty session is our session.
2326 * Locking: RCU, ctrl lock
2329 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2333 int retval = tty_check_change(real_tty);
2334 unsigned long flags;
2340 if (!current->signal->tty ||
2341 (current->signal->tty != real_tty) ||
2342 (real_tty->session != task_session(current)))
2344 if (get_user(pgrp_nr, p))
2349 pgrp = find_vpid(pgrp_nr);
2354 if (session_of_pgrp(pgrp) != task_session(current))
2357 spin_lock_irqsave(&tty->ctrl_lock, flags);
2358 put_pid(real_tty->pgrp);
2359 real_tty->pgrp = get_pid(pgrp);
2360 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2367 * tiocgsid - get session id
2368 * @tty: tty passed by user
2369 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2370 * @p: pointer to returned session id
2372 * Obtain the session id of the tty. If there is no session
2375 * Locking: none. Reference to current->signal->tty is safe.
2378 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2381 * (tty == real_tty) is a cheap way of
2382 * testing if the tty is NOT a master pty.
2384 if (tty == real_tty && current->signal->tty != real_tty)
2386 if (!real_tty->session)
2388 return put_user(pid_vnr(real_tty->session), p);
2392 * tiocsetd - set line discipline
2394 * @p: pointer to user data
2396 * Set the line discipline according to user request.
2398 * Locking: see tty_set_ldisc, this function is just a helper
2401 static int tiocsetd(struct tty_struct *tty, int __user *p)
2406 if (get_user(ldisc, p))
2409 ret = tty_set_ldisc(tty, ldisc);
2415 * send_break - performed time break
2416 * @tty: device to break on
2417 * @duration: timeout in mS
2419 * Perform a timed break on hardware that lacks its own driver level
2420 * timed break functionality.
2423 * atomic_write_lock serializes
2427 static int send_break(struct tty_struct *tty, unsigned int duration)
2431 if (tty->ops->break_ctl == NULL)
2434 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2435 retval = tty->ops->break_ctl(tty, duration);
2437 /* Do the work ourselves */
2438 if (tty_write_lock(tty, 0) < 0)
2440 retval = tty->ops->break_ctl(tty, -1);
2443 if (!signal_pending(current))
2444 msleep_interruptible(duration);
2445 retval = tty->ops->break_ctl(tty, 0);
2447 tty_write_unlock(tty);
2448 if (signal_pending(current))
2455 * tty_tiocmget - get modem status
2457 * @file: user file pointer
2458 * @p: pointer to result
2460 * Obtain the modem status bits from the tty driver if the feature
2461 * is supported. Return -EINVAL if it is not available.
2463 * Locking: none (up to the driver)
2466 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
2468 int retval = -EINVAL;
2470 if (tty->ops->tiocmget) {
2471 retval = tty->ops->tiocmget(tty);
2474 retval = put_user(retval, p);
2480 * tty_tiocmset - set modem status
2482 * @cmd: command - clear bits, set bits or set all
2483 * @p: pointer to desired bits
2485 * Set the modem status bits from the tty driver if the feature
2486 * is supported. Return -EINVAL if it is not available.
2488 * Locking: none (up to the driver)
2491 static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
2495 unsigned int set, clear, val;
2497 if (tty->ops->tiocmset == NULL)
2500 retval = get_user(val, p);
2516 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2517 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2518 return tty->ops->tiocmset(tty, set, clear);
2521 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
2523 int retval = -EINVAL;
2524 struct serial_icounter_struct icount;
2525 memset(&icount, 0, sizeof(icount));
2526 if (tty->ops->get_icount)
2527 retval = tty->ops->get_icount(tty, &icount);
2530 if (copy_to_user(arg, &icount, sizeof(icount)))
2535 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2537 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2538 tty->driver->subtype == PTY_TYPE_MASTER)
2542 EXPORT_SYMBOL(tty_pair_get_tty);
2544 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2546 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2547 tty->driver->subtype == PTY_TYPE_MASTER)
2551 EXPORT_SYMBOL(tty_pair_get_pty);
2554 * Split this up, as gcc can choke on it otherwise..
2556 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2558 struct tty_struct *tty = file_tty(file);
2559 struct tty_struct *real_tty;
2560 void __user *p = (void __user *)arg;
2562 struct tty_ldisc *ld;
2563 struct inode *inode = file->f_dentry->d_inode;
2565 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2568 real_tty = tty_pair_get_tty(tty);
2571 * Factor out some common prep work
2579 retval = tty_check_change(tty);
2582 if (cmd != TIOCCBRK) {
2583 tty_wait_until_sent(tty, 0);
2584 if (signal_pending(current))
2595 return tiocsti(tty, p);
2597 return tiocgwinsz(real_tty, p);
2599 return tiocswinsz(real_tty, p);
2601 return real_tty != tty ? -EINVAL : tioccons(file);
2603 return fionbio(file, p);
2605 set_bit(TTY_EXCLUSIVE, &tty->flags);
2608 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2611 if (current->signal->tty != tty)
2616 return tiocsctty(tty, arg);
2618 return tiocgpgrp(tty, real_tty, p);
2620 return tiocspgrp(tty, real_tty, p);
2622 return tiocgsid(tty, real_tty, p);
2624 return put_user(tty->ldisc->ops->num, (int __user *)p);
2626 return tiocsetd(tty, p);
2628 if (!capable(CAP_SYS_ADMIN))
2634 unsigned int ret = new_encode_dev(tty_devnum(real_tty));
2635 return put_user(ret, (unsigned int __user *)p);
2640 case TIOCSBRK: /* Turn break on, unconditionally */
2641 if (tty->ops->break_ctl)
2642 return tty->ops->break_ctl(tty, -1);
2644 case TIOCCBRK: /* Turn break off, unconditionally */
2645 if (tty->ops->break_ctl)
2646 return tty->ops->break_ctl(tty, 0);
2648 case TCSBRK: /* SVID version: non-zero arg --> no break */
2649 /* non-zero arg means wait for all output data
2650 * to be sent (performed above) but don't send break.
2651 * This is used by the tcdrain() termios function.
2654 return send_break(tty, 250);
2656 case TCSBRKP: /* support for POSIX tcsendbreak() */
2657 return send_break(tty, arg ? arg*100 : 250);
2660 return tty_tiocmget(tty, p);
2664 return tty_tiocmset(tty, cmd, p);
2666 retval = tty_tiocgicount(tty, p);
2667 /* For the moment allow fall through to the old method */
2668 if (retval != -EINVAL)
2675 /* flush tty buffer and allow ldisc to process ioctl */
2676 tty_buffer_flush(tty);
2681 if (tty->ops->ioctl) {
2682 retval = (tty->ops->ioctl)(tty, cmd, arg);
2683 if (retval != -ENOIOCTLCMD)
2686 ld = tty_ldisc_ref_wait(tty);
2688 if (ld->ops->ioctl) {
2689 retval = ld->ops->ioctl(tty, file, cmd, arg);
2690 if (retval == -ENOIOCTLCMD)
2693 tty_ldisc_deref(ld);
2697 #ifdef CONFIG_COMPAT
2698 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2701 struct inode *inode = file->f_dentry->d_inode;
2702 struct tty_struct *tty = file_tty(file);
2703 struct tty_ldisc *ld;
2704 int retval = -ENOIOCTLCMD;
2706 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2709 if (tty->ops->compat_ioctl) {
2710 retval = (tty->ops->compat_ioctl)(tty, cmd, arg);
2711 if (retval != -ENOIOCTLCMD)
2715 ld = tty_ldisc_ref_wait(tty);
2716 if (ld->ops->compat_ioctl)
2717 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2718 tty_ldisc_deref(ld);
2725 * This implements the "Secure Attention Key" --- the idea is to
2726 * prevent trojan horses by killing all processes associated with this
2727 * tty when the user hits the "Secure Attention Key". Required for
2728 * super-paranoid applications --- see the Orange Book for more details.
2730 * This code could be nicer; ideally it should send a HUP, wait a few
2731 * seconds, then send a INT, and then a KILL signal. But you then
2732 * have to coordinate with the init process, since all processes associated
2733 * with the current tty must be dead before the new getty is allowed
2736 * Now, if it would be correct ;-/ The current code has a nasty hole -
2737 * it doesn't catch files in flight. We may send the descriptor to ourselves
2738 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2740 * Nasty bug: do_SAK is being called in interrupt context. This can
2741 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2743 void __do_SAK(struct tty_struct *tty)
2748 struct task_struct *g, *p;
2749 struct pid *session;
2752 struct fdtable *fdt;
2756 session = tty->session;
2758 tty_ldisc_flush(tty);
2760 tty_driver_flush_buffer(tty);
2762 read_lock(&tasklist_lock);
2763 /* Kill the entire session */
2764 do_each_pid_task(session, PIDTYPE_SID, p) {
2765 printk(KERN_NOTICE "SAK: killed process %d"
2766 " (%s): task_session(p)==tty->session\n",
2767 task_pid_nr(p), p->comm);
2768 send_sig(SIGKILL, p, 1);
2769 } while_each_pid_task(session, PIDTYPE_SID, p);
2770 /* Now kill any processes that happen to have the
2773 do_each_thread(g, p) {
2774 if (p->signal->tty == tty) {
2775 printk(KERN_NOTICE "SAK: killed process %d"
2776 " (%s): task_session(p)==tty->session\n",
2777 task_pid_nr(p), p->comm);
2778 send_sig(SIGKILL, p, 1);
2784 * We don't take a ref to the file, so we must
2785 * hold ->file_lock instead.
2787 spin_lock(&p->files->file_lock);
2788 fdt = files_fdtable(p->files);
2789 for (i = 0; i < fdt->max_fds; i++) {
2790 filp = fcheck_files(p->files, i);
2793 if (filp->f_op->read == tty_read &&
2794 file_tty(filp) == tty) {
2795 printk(KERN_NOTICE "SAK: killed process %d"
2796 " (%s): fd#%d opened to the tty\n",
2797 task_pid_nr(p), p->comm, i);
2798 force_sig(SIGKILL, p);
2802 spin_unlock(&p->files->file_lock);
2805 } while_each_thread(g, p);
2806 read_unlock(&tasklist_lock);
2810 static void do_SAK_work(struct work_struct *work)
2812 struct tty_struct *tty =
2813 container_of(work, struct tty_struct, SAK_work);
2818 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2819 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2820 * the values which we write to it will be identical to the values which it
2821 * already has. --akpm
2823 void do_SAK(struct tty_struct *tty)
2827 schedule_work(&tty->SAK_work);
2830 EXPORT_SYMBOL(do_SAK);
2832 static int dev_match_devt(struct device *dev, void *data)
2835 return dev->devt == *devt;
2838 /* Must put_device() after it's unused! */
2839 static struct device *tty_get_device(struct tty_struct *tty)
2841 dev_t devt = tty_devnum(tty);
2842 return class_find_device(tty_class, NULL, &devt, dev_match_devt);
2847 * initialize_tty_struct
2848 * @tty: tty to initialize
2850 * This subroutine initializes a tty structure that has been newly
2853 * Locking: none - tty in question must not be exposed at this point
2856 void initialize_tty_struct(struct tty_struct *tty,
2857 struct tty_driver *driver, int idx)
2859 memset(tty, 0, sizeof(struct tty_struct));
2860 kref_init(&tty->kref);
2861 tty->magic = TTY_MAGIC;
2862 tty_ldisc_init(tty);
2863 tty->session = NULL;
2865 tty->overrun_time = jiffies;
2866 tty->buf.head = tty->buf.tail = NULL;
2867 tty_buffer_init(tty);
2868 mutex_init(&tty->termios_mutex);
2869 mutex_init(&tty->ldisc_mutex);
2870 init_waitqueue_head(&tty->write_wait);
2871 init_waitqueue_head(&tty->read_wait);
2872 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2873 mutex_init(&tty->atomic_read_lock);
2874 mutex_init(&tty->atomic_write_lock);
2875 mutex_init(&tty->output_lock);
2876 mutex_init(&tty->echo_lock);
2877 spin_lock_init(&tty->read_lock);
2878 spin_lock_init(&tty->ctrl_lock);
2879 INIT_LIST_HEAD(&tty->tty_files);
2880 INIT_WORK(&tty->SAK_work, do_SAK_work);
2882 tty->driver = driver;
2883 tty->ops = driver->ops;
2885 tty_line_name(driver, idx, tty->name);
2886 tty->dev = tty_get_device(tty);
2890 * deinitialize_tty_struct
2891 * @tty: tty to deinitialize
2893 * This subroutine deinitializes a tty structure that has been newly
2894 * allocated but tty_release cannot be called on that yet.
2896 * Locking: none - tty in question must not be exposed at this point
2898 void deinitialize_tty_struct(struct tty_struct *tty)
2900 tty_ldisc_deinit(tty);
2904 * tty_put_char - write one character to a tty
2908 * Write one byte to the tty using the provided put_char method
2909 * if present. Returns the number of characters successfully output.
2911 * Note: the specific put_char operation in the driver layer may go
2912 * away soon. Don't call it directly, use this method
2915 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2917 if (tty->ops->put_char)
2918 return tty->ops->put_char(tty, ch);
2919 return tty->ops->write(tty, &ch, 1);
2921 EXPORT_SYMBOL_GPL(tty_put_char);
2923 struct class *tty_class;
2926 * tty_register_device - register a tty device
2927 * @driver: the tty driver that describes the tty device
2928 * @index: the index in the tty driver for this tty device
2929 * @device: a struct device that is associated with this tty device.
2930 * This field is optional, if there is no known struct device
2931 * for this tty device it can be set to NULL safely.
2933 * Returns a pointer to the struct device for this tty device
2934 * (or ERR_PTR(-EFOO) on error).
2936 * This call is required to be made to register an individual tty device
2937 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2938 * that bit is not set, this function should not be called by a tty
2944 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2945 struct device *device)
2948 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2950 if (index >= driver->num) {
2951 printk(KERN_ERR "Attempt to register invalid tty line number "
2953 return ERR_PTR(-EINVAL);
2956 if (driver->type == TTY_DRIVER_TYPE_PTY)
2957 pty_line_name(driver, index, name);
2959 tty_line_name(driver, index, name);
2961 return device_create(tty_class, device, dev, NULL, name);
2963 EXPORT_SYMBOL(tty_register_device);
2966 * tty_unregister_device - unregister a tty device
2967 * @driver: the tty driver that describes the tty device
2968 * @index: the index in the tty driver for this tty device
2970 * If a tty device is registered with a call to tty_register_device() then
2971 * this function must be called when the tty device is gone.
2976 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2978 device_destroy(tty_class,
2979 MKDEV(driver->major, driver->minor_start) + index);
2981 EXPORT_SYMBOL(tty_unregister_device);
2983 struct tty_driver *alloc_tty_driver(int lines)
2985 struct tty_driver *driver;
2987 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2989 kref_init(&driver->kref);
2990 driver->magic = TTY_DRIVER_MAGIC;
2991 driver->num = lines;
2992 /* later we'll move allocation of tables here */
2996 EXPORT_SYMBOL(alloc_tty_driver);
2998 static void destruct_tty_driver(struct kref *kref)
3000 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
3002 struct ktermios *tp;
3005 if (driver->flags & TTY_DRIVER_INSTALLED) {
3007 * Free the termios and termios_locked structures because
3008 * we don't want to get memory leaks when modular tty
3009 * drivers are removed from the kernel.
3011 for (i = 0; i < driver->num; i++) {
3012 tp = driver->termios[i];
3014 driver->termios[i] = NULL;
3017 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
3018 tty_unregister_device(driver, i);
3021 proc_tty_unregister_driver(driver);
3022 driver->ttys = NULL;
3023 driver->termios = NULL;
3025 cdev_del(&driver->cdev);
3030 void tty_driver_kref_put(struct tty_driver *driver)
3032 kref_put(&driver->kref, destruct_tty_driver);
3034 EXPORT_SYMBOL(tty_driver_kref_put);
3036 void tty_set_operations(struct tty_driver *driver,
3037 const struct tty_operations *op)
3041 EXPORT_SYMBOL(tty_set_operations);
3043 void put_tty_driver(struct tty_driver *d)
3045 tty_driver_kref_put(d);
3047 EXPORT_SYMBOL(put_tty_driver);
3050 * Called by a tty driver to register itself.
3052 int tty_register_driver(struct tty_driver *driver)
3060 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
3061 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
3066 if (!driver->major) {
3067 error = alloc_chrdev_region(&dev, driver->minor_start,
3068 driver->num, driver->name);
3070 driver->major = MAJOR(dev);
3071 driver->minor_start = MINOR(dev);
3074 dev = MKDEV(driver->major, driver->minor_start);
3075 error = register_chrdev_region(dev, driver->num, driver->name);
3083 driver->ttys = (struct tty_struct **)p;
3084 driver->termios = (struct ktermios **)(p + driver->num);
3086 driver->ttys = NULL;
3087 driver->termios = NULL;
3090 cdev_init(&driver->cdev, &tty_fops);
3091 driver->cdev.owner = driver->owner;
3092 error = cdev_add(&driver->cdev, dev, driver->num);
3094 unregister_chrdev_region(dev, driver->num);
3095 driver->ttys = NULL;
3096 driver->termios = NULL;
3101 mutex_lock(&tty_mutex);
3102 list_add(&driver->tty_drivers, &tty_drivers);
3103 mutex_unlock(&tty_mutex);
3105 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3106 for (i = 0; i < driver->num; i++) {
3107 d = tty_register_device(driver, i, NULL);
3114 proc_tty_register_driver(driver);
3115 driver->flags |= TTY_DRIVER_INSTALLED;
3119 for (i--; i >= 0; i--)
3120 tty_unregister_device(driver, i);
3122 mutex_lock(&tty_mutex);
3123 list_del(&driver->tty_drivers);
3124 mutex_unlock(&tty_mutex);
3126 unregister_chrdev_region(dev, driver->num);
3127 driver->ttys = NULL;
3128 driver->termios = NULL;
3133 EXPORT_SYMBOL(tty_register_driver);
3136 * Called by a tty driver to unregister itself.
3138 int tty_unregister_driver(struct tty_driver *driver)
3142 if (driver->refcount)
3145 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3147 mutex_lock(&tty_mutex);
3148 list_del(&driver->tty_drivers);
3149 mutex_unlock(&tty_mutex);
3153 EXPORT_SYMBOL(tty_unregister_driver);
3155 dev_t tty_devnum(struct tty_struct *tty)
3157 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3159 EXPORT_SYMBOL(tty_devnum);
3161 void proc_clear_tty(struct task_struct *p)
3163 unsigned long flags;
3164 struct tty_struct *tty;
3165 spin_lock_irqsave(&p->sighand->siglock, flags);
3166 tty = p->signal->tty;
3167 p->signal->tty = NULL;
3168 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3172 /* Called under the sighand lock */
3174 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3177 unsigned long flags;
3178 /* We should not have a session or pgrp to put here but.... */
3179 spin_lock_irqsave(&tty->ctrl_lock, flags);
3180 put_pid(tty->session);
3182 tty->pgrp = get_pid(task_pgrp(tsk));
3183 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3184 tty->session = get_pid(task_session(tsk));
3185 if (tsk->signal->tty) {
3186 printk(KERN_DEBUG "tty not NULL!!\n");
3187 tty_kref_put(tsk->signal->tty);
3190 put_pid(tsk->signal->tty_old_pgrp);
3191 tsk->signal->tty = tty_kref_get(tty);
3192 tsk->signal->tty_old_pgrp = NULL;
3195 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3197 spin_lock_irq(&tsk->sighand->siglock);
3198 __proc_set_tty(tsk, tty);
3199 spin_unlock_irq(&tsk->sighand->siglock);
3202 struct tty_struct *get_current_tty(void)
3204 struct tty_struct *tty;
3205 unsigned long flags;
3207 spin_lock_irqsave(¤t->sighand->siglock, flags);
3208 tty = tty_kref_get(current->signal->tty);
3209 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3212 EXPORT_SYMBOL_GPL(get_current_tty);
3214 void tty_default_fops(struct file_operations *fops)
3220 * Initialize the console device. This is called *early*, so
3221 * we can't necessarily depend on lots of kernel help here.
3222 * Just do some early initializations, and do the complex setup
3225 void __init console_init(void)
3229 /* Setup the default TTY line discipline. */
3233 * set up the console device so that later boot sequences can
3234 * inform about problems etc..
3236 call = __con_initcall_start;
3237 while (call < __con_initcall_end) {
3243 static char *tty_devnode(struct device *dev, mode_t *mode)
3247 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3248 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3253 static int __init tty_class_init(void)
3255 tty_class = class_create(THIS_MODULE, "tty");
3256 if (IS_ERR(tty_class))
3257 return PTR_ERR(tty_class);
3258 tty_class->devnode = tty_devnode;
3262 postcore_initcall(tty_class_init);
3264 /* 3/2004 jmc: why do these devices exist? */
3265 static struct cdev tty_cdev, console_cdev;
3267 static ssize_t show_cons_active(struct device *dev,
3268 struct device_attribute *attr, char *buf)
3270 struct console *cs[16];
3276 for_each_console(c) {
3281 if ((c->flags & CON_ENABLED) == 0)
3284 if (i >= ARRAY_SIZE(cs))
3288 count += sprintf(buf + count, "%s%d%c",
3289 cs[i]->name, cs[i]->index, i ? ' ':'\n');
3294 static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
3296 static struct device *consdev;
3298 void console_sysfs_notify(void)
3301 sysfs_notify(&consdev->kobj, NULL, "active");
3305 * Ok, now we can initialize the rest of the tty devices and can count
3306 * on memory allocations, interrupts etc..
3308 int __init tty_init(void)
3310 cdev_init(&tty_cdev, &tty_fops);
3311 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3312 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3313 panic("Couldn't register /dev/tty driver\n");
3314 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
3316 cdev_init(&console_cdev, &console_fops);
3317 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3318 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3319 panic("Couldn't register /dev/console driver\n");
3320 consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3322 if (IS_ERR(consdev))
3325 WARN_ON(device_create_file(consdev, &dev_attr_active) < 0);
3328 vty_init(&console_fops);