2 * linux/drivers/char/tty_io.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
9 * or rs-channels. It also implements echoing, cooked mode etc.
11 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
13 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
14 * tty_struct and tty_queue structures. Previously there was an array
15 * of 256 tty_struct's which was statically allocated, and the
16 * tty_queue structures were allocated at boot time. Both are now
17 * dynamically allocated only when the tty is open.
19 * Also restructured routines so that there is more of a separation
20 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
21 * the low-level tty routines (serial.c, pty.c, console.c). This
22 * makes for cleaner and more compact code. -TYT, 9/17/92
24 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
25 * which can be dynamically activated and de-activated by the line
26 * discipline handling modules (like SLIP).
28 * NOTE: pay no attention to the line discipline code (yet); its
29 * interface is still subject to change in this version...
32 * Added functionality to the OPOST tty handling. No delays, but all
33 * other bits should be there.
34 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
36 * Rewrote canonical mode and added more termios flags.
37 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
39 * Reorganized FASYNC support so mouse code can share it.
40 * -- ctm@ardi.com, 9Sep95
42 * New TIOCLINUX variants added.
43 * -- mj@k332.feld.cvut.cz, 19-Nov-95
45 * Restrict vt switching via ioctl()
46 * -- grif@cs.ucr.edu, 5-Dec-95
48 * Move console and virtual terminal code to more appropriate files,
49 * implement CONFIG_VT and generalize console device interface.
50 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
52 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
53 * -- Bill Hawes <whawes@star.net>, June 97
55 * Added devfs support.
56 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
58 * Added support for a Unix98-style ptmx device.
59 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
61 * Reduced memory usage for older ARM systems
62 * -- Russell King <rmk@arm.linux.org.uk>
64 * Move do_SAK() into process context. Less stack use in devfs functions.
65 * alloc_tty_struct() always uses kmalloc()
66 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
69 #include <linux/types.h>
70 #include <linux/major.h>
71 #include <linux/errno.h>
72 #include <linux/signal.h>
73 #include <linux/fcntl.h>
74 #include <linux/sched.h>
75 #include <linux/interrupt.h>
76 #include <linux/tty.h>
77 #include <linux/tty_driver.h>
78 #include <linux/tty_flip.h>
79 #include <linux/devpts_fs.h>
80 #include <linux/file.h>
81 #include <linux/fdtable.h>
82 #include <linux/console.h>
83 #include <linux/timer.h>
84 #include <linux/ctype.h>
87 #include <linux/string.h>
88 #include <linux/slab.h>
89 #include <linux/poll.h>
90 #include <linux/proc_fs.h>
91 #include <linux/init.h>
92 #include <linux/module.h>
93 #include <linux/smp_lock.h>
94 #include <linux/device.h>
95 #include <linux/wait.h>
96 #include <linux/bitops.h>
97 #include <linux/delay.h>
98 #include <linux/seq_file.h>
100 #include <linux/uaccess.h>
101 #include <asm/system.h>
103 #include <linux/kbd_kern.h>
104 #include <linux/vt_kern.h>
105 #include <linux/selection.h>
107 #include <linux/kmod.h>
108 #include <linux/nsproxy.h>
110 #undef TTY_DEBUG_HANGUP
112 #define TTY_PARANOIA_CHECK 1
113 #define CHECK_TTY_COUNT 1
115 struct ktermios tty_std_termios = { /* for the benefit of tty drivers */
116 .c_iflag = ICRNL | IXON,
117 .c_oflag = OPOST | ONLCR,
118 .c_cflag = B38400 | CS8 | CREAD | HUPCL,
119 .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK |
120 ECHOCTL | ECHOKE | IEXTEN,
126 EXPORT_SYMBOL(tty_std_termios);
128 /* This list gets poked at by procfs and various bits of boot up code. This
129 could do with some rationalisation such as pulling the tty proc function
132 LIST_HEAD(tty_drivers); /* linked list of tty drivers */
134 /* Mutex to protect creating and releasing a tty. This is shared with
135 vt.c for deeply disgusting hack reasons */
136 DEFINE_MUTEX(tty_mutex);
137 EXPORT_SYMBOL(tty_mutex);
139 /* Spinlock to protect the tty->tty_files list */
140 DEFINE_SPINLOCK(tty_files_lock);
142 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
143 static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *);
144 ssize_t redirected_tty_write(struct file *, const char __user *,
146 static unsigned int tty_poll(struct file *, poll_table *);
147 static int tty_open(struct inode *, struct file *);
148 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
150 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
153 #define tty_compat_ioctl NULL
155 static int __tty_fasync(int fd, struct file *filp, int on);
156 static int tty_fasync(int fd, struct file *filp, int on);
157 static void release_tty(struct tty_struct *tty, int idx);
158 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
159 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
162 * alloc_tty_struct - allocate a tty object
164 * Return a new empty tty structure. The data fields have not
165 * been initialized in any way but has been zeroed
170 struct tty_struct *alloc_tty_struct(void)
172 return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
176 * free_tty_struct - free a disused tty
177 * @tty: tty struct to free
179 * Free the write buffers, tty queue and tty memory itself.
181 * Locking: none. Must be called after tty is definitely unused
184 void free_tty_struct(struct tty_struct *tty)
186 kfree(tty->write_buf);
187 tty_buffer_free_all(tty);
191 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
194 * tty_name - return tty naming
195 * @tty: tty structure
196 * @buf: buffer for output
198 * Convert a tty structure into a name. The name reflects the kernel
199 * naming policy and if udev is in use may not reflect user space
204 char *tty_name(struct tty_struct *tty, char *buf)
206 if (!tty) /* Hmm. NULL pointer. That's fun. */
207 strcpy(buf, "NULL tty");
209 strcpy(buf, tty->name);
213 EXPORT_SYMBOL(tty_name);
215 int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
218 #ifdef TTY_PARANOIA_CHECK
221 "null TTY for (%d:%d) in %s\n",
222 imajor(inode), iminor(inode), routine);
225 if (tty->magic != TTY_MAGIC) {
227 "bad magic number for tty struct (%d:%d) in %s\n",
228 imajor(inode), iminor(inode), routine);
235 static int check_tty_count(struct tty_struct *tty, const char *routine)
237 #ifdef CHECK_TTY_COUNT
241 spin_lock(&tty_files_lock);
242 list_for_each(p, &tty->tty_files) {
245 spin_unlock(&tty_files_lock);
246 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
247 tty->driver->subtype == PTY_TYPE_SLAVE &&
248 tty->link && tty->link->count)
250 if (tty->count != count) {
251 printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) "
252 "!= #fd's(%d) in %s\n",
253 tty->name, tty->count, count, routine);
261 * get_tty_driver - find device of a tty
262 * @dev_t: device identifier
263 * @index: returns the index of the tty
265 * This routine returns a tty driver structure, given a device number
266 * and also passes back the index number.
268 * Locking: caller must hold tty_mutex
271 static struct tty_driver *get_tty_driver(dev_t device, int *index)
273 struct tty_driver *p;
275 list_for_each_entry(p, &tty_drivers, tty_drivers) {
276 dev_t base = MKDEV(p->major, p->minor_start);
277 if (device < base || device >= base + p->num)
279 *index = device - base;
280 return tty_driver_kref_get(p);
285 #ifdef CONFIG_CONSOLE_POLL
288 * tty_find_polling_driver - find device of a polled tty
289 * @name: name string to match
290 * @line: pointer to resulting tty line nr
292 * This routine returns a tty driver structure, given a name
293 * and the condition that the tty driver is capable of polled
296 struct tty_driver *tty_find_polling_driver(char *name, int *line)
298 struct tty_driver *p, *res = NULL;
303 for (str = name; *str; str++)
304 if ((*str >= '0' && *str <= '9') || *str == ',')
310 tty_line = simple_strtoul(str, &str, 10);
312 mutex_lock(&tty_mutex);
313 /* Search through the tty devices to look for a match */
314 list_for_each_entry(p, &tty_drivers, tty_drivers) {
315 if (strncmp(name, p->name, len) != 0)
323 if (tty_line >= 0 && tty_line <= p->num && p->ops &&
324 p->ops->poll_init && !p->ops->poll_init(p, tty_line, stp)) {
325 res = tty_driver_kref_get(p);
330 mutex_unlock(&tty_mutex);
334 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
338 * tty_check_change - check for POSIX terminal changes
341 * If we try to write to, or set the state of, a terminal and we're
342 * not in the foreground, send a SIGTTOU. If the signal is blocked or
343 * ignored, go ahead and perform the operation. (POSIX 7.2)
348 int tty_check_change(struct tty_struct *tty)
353 if (current->signal->tty != tty)
356 spin_lock_irqsave(&tty->ctrl_lock, flags);
359 printk(KERN_WARNING "tty_check_change: tty->pgrp == NULL!\n");
362 if (task_pgrp(current) == tty->pgrp)
364 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
365 if (is_ignored(SIGTTOU))
367 if (is_current_pgrp_orphaned()) {
371 kill_pgrp(task_pgrp(current), SIGTTOU, 1);
372 set_thread_flag(TIF_SIGPENDING);
377 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
381 EXPORT_SYMBOL(tty_check_change);
383 static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
384 size_t count, loff_t *ppos)
389 static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
390 size_t count, loff_t *ppos)
395 /* No kernel lock held - none needed ;) */
396 static unsigned int hung_up_tty_poll(struct file *filp, poll_table *wait)
398 return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM;
401 static long hung_up_tty_ioctl(struct file *file, unsigned int cmd,
404 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
407 static long hung_up_tty_compat_ioctl(struct file *file,
408 unsigned int cmd, unsigned long arg)
410 return cmd == TIOCSPGRP ? -ENOTTY : -EIO;
413 static const struct file_operations tty_fops = {
418 .unlocked_ioctl = tty_ioctl,
419 .compat_ioctl = tty_compat_ioctl,
421 .release = tty_release,
422 .fasync = tty_fasync,
425 static const struct file_operations console_fops = {
428 .write = redirected_tty_write,
430 .unlocked_ioctl = tty_ioctl,
431 .compat_ioctl = tty_compat_ioctl,
433 .release = tty_release,
434 .fasync = tty_fasync,
437 static const struct file_operations hung_up_tty_fops = {
439 .read = hung_up_tty_read,
440 .write = hung_up_tty_write,
441 .poll = hung_up_tty_poll,
442 .unlocked_ioctl = hung_up_tty_ioctl,
443 .compat_ioctl = hung_up_tty_compat_ioctl,
444 .release = tty_release,
447 static DEFINE_SPINLOCK(redirect_lock);
448 static struct file *redirect;
451 * tty_wakeup - request more data
454 * Internal and external helper for wakeups of tty. This function
455 * informs the line discipline if present that the driver is ready
456 * to receive more output data.
459 void tty_wakeup(struct tty_struct *tty)
461 struct tty_ldisc *ld;
463 if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) {
464 ld = tty_ldisc_ref(tty);
466 if (ld->ops->write_wakeup)
467 ld->ops->write_wakeup(tty);
471 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
474 EXPORT_SYMBOL_GPL(tty_wakeup);
477 * __tty_hangup - actual handler for hangup events
480 * This can be called by the "eventd" kernel thread. That is process
481 * synchronous but doesn't hold any locks, so we need to make sure we
482 * have the appropriate locks for what we're doing.
484 * The hangup event clears any pending redirections onto the hung up
485 * device. It ensures future writes will error and it does the needed
486 * line discipline hangup and signal delivery. The tty object itself
491 * redirect lock for undoing redirection
492 * file list lock for manipulating list of ttys
493 * tty_ldisc_lock from called functions
494 * termios_mutex resetting termios data
495 * tasklist_lock to walk task list for hangup event
496 * ->siglock to protect ->signal/->sighand
498 void __tty_hangup(struct tty_struct *tty)
500 struct file *cons_filp = NULL;
501 struct file *filp, *f = NULL;
502 struct task_struct *p;
503 int closecount = 0, n;
511 spin_lock(&redirect_lock);
512 if (redirect && redirect->private_data == tty) {
516 spin_unlock(&redirect_lock);
520 /* inuse_filps is protected by the single tty lock,
521 this really needs to change if we want to flush the
522 workqueue with the lock held */
523 check_tty_count(tty, "tty_hangup");
525 spin_lock(&tty_files_lock);
526 /* This breaks for file handles being sent over AF_UNIX sockets ? */
527 list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) {
528 if (filp->f_op->write == redirected_tty_write)
530 if (filp->f_op->write != tty_write)
533 __tty_fasync(-1, filp, 0); /* can't block */
534 filp->f_op = &hung_up_tty_fops;
536 spin_unlock(&tty_files_lock);
538 tty_ldisc_hangup(tty);
540 read_lock(&tasklist_lock);
542 do_each_pid_task(tty->session, PIDTYPE_SID, p) {
543 spin_lock_irq(&p->sighand->siglock);
544 if (p->signal->tty == tty) {
545 p->signal->tty = NULL;
546 /* We defer the dereferences outside fo
550 if (!p->signal->leader) {
551 spin_unlock_irq(&p->sighand->siglock);
554 __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
555 __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
556 put_pid(p->signal->tty_old_pgrp); /* A noop */
557 spin_lock_irqsave(&tty->ctrl_lock, flags);
559 p->signal->tty_old_pgrp = get_pid(tty->pgrp);
560 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
561 spin_unlock_irq(&p->sighand->siglock);
562 } while_each_pid_task(tty->session, PIDTYPE_SID, p);
564 read_unlock(&tasklist_lock);
566 spin_lock_irqsave(&tty->ctrl_lock, flags);
567 clear_bit(TTY_THROTTLED, &tty->flags);
568 clear_bit(TTY_PUSH, &tty->flags);
569 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
570 put_pid(tty->session);
574 tty->ctrl_status = 0;
575 set_bit(TTY_HUPPED, &tty->flags);
576 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
578 /* Account for the p->signal references we killed */
583 * If one of the devices matches a console pointer, we
584 * cannot just call hangup() because that will cause
585 * tty->count and state->count to go out of sync.
586 * So we just call close() the right number of times.
590 for (n = 0; n < closecount; n++)
591 tty->ops->close(tty, cons_filp);
592 } else if (tty->ops->hangup)
593 (tty->ops->hangup)(tty);
595 * We don't want to have driver/ldisc interactions beyond
596 * the ones we did here. The driver layer expects no
597 * calls after ->hangup() from the ldisc side. However we
598 * can't yet guarantee all that.
600 set_bit(TTY_HUPPED, &tty->flags);
601 tty_ldisc_enable(tty);
609 static void do_tty_hangup(struct work_struct *work)
611 struct tty_struct *tty =
612 container_of(work, struct tty_struct, hangup_work);
618 * tty_hangup - trigger a hangup event
619 * @tty: tty to hangup
621 * A carrier loss (virtual or otherwise) has occurred on this like
622 * schedule a hangup sequence to run after this event.
625 void tty_hangup(struct tty_struct *tty)
627 #ifdef TTY_DEBUG_HANGUP
629 printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf));
631 schedule_work(&tty->hangup_work);
634 EXPORT_SYMBOL(tty_hangup);
637 * tty_vhangup - process vhangup
638 * @tty: tty to hangup
640 * The user has asked via system call for the terminal to be hung up.
641 * We do this synchronously so that when the syscall returns the process
642 * is complete. That guarantee is necessary for security reasons.
645 void tty_vhangup(struct tty_struct *tty)
647 #ifdef TTY_DEBUG_HANGUP
650 printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
655 EXPORT_SYMBOL(tty_vhangup);
659 * tty_vhangup_self - process vhangup for own ctty
661 * Perform a vhangup on the current controlling tty
664 void tty_vhangup_self(void)
666 struct tty_struct *tty;
668 tty = get_current_tty();
676 * tty_hung_up_p - was tty hung up
677 * @filp: file pointer of tty
679 * Return true if the tty has been subject to a vhangup or a carrier
683 int tty_hung_up_p(struct file *filp)
685 return (filp->f_op == &hung_up_tty_fops);
688 EXPORT_SYMBOL(tty_hung_up_p);
690 static void session_clear_tty(struct pid *session)
692 struct task_struct *p;
693 do_each_pid_task(session, PIDTYPE_SID, p) {
695 } while_each_pid_task(session, PIDTYPE_SID, p);
699 * disassociate_ctty - disconnect controlling tty
700 * @on_exit: true if exiting so need to "hang up" the session
702 * This function is typically called only by the session leader, when
703 * it wants to disassociate itself from its controlling tty.
705 * It performs the following functions:
706 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
707 * (2) Clears the tty from being controlling the session
708 * (3) Clears the controlling tty for all processes in the
711 * The argument on_exit is set to 1 if called when a process is
712 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
715 * BTM is taken for hysterical raisins, and held when
716 * called from no_tty().
717 * tty_mutex is taken to protect tty
718 * ->siglock is taken to protect ->signal/->sighand
719 * tasklist_lock is taken to walk process list for sessions
720 * ->siglock is taken to protect ->signal/->sighand
723 void disassociate_ctty(int on_exit)
725 struct tty_struct *tty;
726 struct pid *tty_pgrp = NULL;
728 if (!current->signal->leader)
731 tty = get_current_tty();
733 tty_pgrp = get_pid(tty->pgrp);
735 if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
739 } else if (on_exit) {
740 struct pid *old_pgrp;
741 spin_lock_irq(¤t->sighand->siglock);
742 old_pgrp = current->signal->tty_old_pgrp;
743 current->signal->tty_old_pgrp = NULL;
744 spin_unlock_irq(¤t->sighand->siglock);
746 kill_pgrp(old_pgrp, SIGHUP, on_exit);
747 kill_pgrp(old_pgrp, SIGCONT, on_exit);
753 kill_pgrp(tty_pgrp, SIGHUP, on_exit);
755 kill_pgrp(tty_pgrp, SIGCONT, on_exit);
759 spin_lock_irq(¤t->sighand->siglock);
760 put_pid(current->signal->tty_old_pgrp);
761 current->signal->tty_old_pgrp = NULL;
762 spin_unlock_irq(¤t->sighand->siglock);
764 tty = get_current_tty();
767 spin_lock_irqsave(&tty->ctrl_lock, flags);
768 put_pid(tty->session);
772 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
775 #ifdef TTY_DEBUG_HANGUP
776 printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
781 /* Now clear signal->tty under the lock */
782 read_lock(&tasklist_lock);
783 session_clear_tty(task_session(current));
784 read_unlock(&tasklist_lock);
789 * no_tty - Ensure the current process does not have a controlling tty
793 struct task_struct *tsk = current;
795 disassociate_ctty(0);
802 * stop_tty - propagate flow control
805 * Perform flow control to the driver. For PTY/TTY pairs we
806 * must also propagate the TIOCKPKT status. May be called
807 * on an already stopped device and will not re-call the driver
810 * This functionality is used by both the line disciplines for
811 * halting incoming flow and by the driver. It may therefore be
812 * called from any context, may be under the tty atomic_write_lock
816 * Uses the tty control lock internally
819 void stop_tty(struct tty_struct *tty)
822 spin_lock_irqsave(&tty->ctrl_lock, flags);
824 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
828 if (tty->link && tty->link->packet) {
829 tty->ctrl_status &= ~TIOCPKT_START;
830 tty->ctrl_status |= TIOCPKT_STOP;
831 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
833 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
835 (tty->ops->stop)(tty);
838 EXPORT_SYMBOL(stop_tty);
841 * start_tty - propagate flow control
844 * Start a tty that has been stopped if at all possible. Perform
845 * any necessary wakeups and propagate the TIOCPKT status. If this
846 * is the tty was previous stopped and is being started then the
847 * driver start method is invoked and the line discipline woken.
853 void start_tty(struct tty_struct *tty)
856 spin_lock_irqsave(&tty->ctrl_lock, flags);
857 if (!tty->stopped || tty->flow_stopped) {
858 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
862 if (tty->link && tty->link->packet) {
863 tty->ctrl_status &= ~TIOCPKT_STOP;
864 tty->ctrl_status |= TIOCPKT_START;
865 wake_up_interruptible_poll(&tty->link->read_wait, POLLIN);
867 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
869 (tty->ops->start)(tty);
870 /* If we have a running line discipline it may need kicking */
874 EXPORT_SYMBOL(start_tty);
877 * tty_read - read method for tty device files
878 * @file: pointer to tty file
880 * @count: size of user buffer
883 * Perform the read system call function on this terminal device. Checks
884 * for hung up devices before calling the line discipline method.
887 * Locks the line discipline internally while needed. Multiple
888 * read calls may be outstanding in parallel.
891 static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
895 struct tty_struct *tty;
897 struct tty_ldisc *ld;
899 tty = file->private_data;
900 inode = file->f_path.dentry->d_inode;
901 if (tty_paranoia_check(tty, inode, "tty_read"))
903 if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags)))
906 /* We want to wait for the line discipline to sort out in this
908 ld = tty_ldisc_ref_wait(tty);
910 i = (ld->ops->read)(tty, file, buf, count);
915 inode->i_atime = current_fs_time(inode->i_sb);
919 void tty_write_unlock(struct tty_struct *tty)
921 mutex_unlock(&tty->atomic_write_lock);
922 wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
925 int tty_write_lock(struct tty_struct *tty, int ndelay)
927 if (!mutex_trylock(&tty->atomic_write_lock)) {
930 if (mutex_lock_interruptible(&tty->atomic_write_lock))
937 * Split writes up in sane blocksizes to avoid
938 * denial-of-service type attacks
940 static inline ssize_t do_tty_write(
941 ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t),
942 struct tty_struct *tty,
944 const char __user *buf,
947 ssize_t ret, written = 0;
950 ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
955 * We chunk up writes into a temporary buffer. This
956 * simplifies low-level drivers immensely, since they
957 * don't have locking issues and user mode accesses.
959 * But if TTY_NO_WRITE_SPLIT is set, we should use a
962 * The default chunk-size is 2kB, because the NTTY
963 * layer has problems with bigger chunks. It will
964 * claim to be able to handle more characters than
967 * FIXME: This can probably go away now except that 64K chunks
968 * are too likely to fail unless switched to vmalloc...
971 if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags))
976 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
977 if (tty->write_cnt < chunk) {
978 unsigned char *buf_chunk;
983 buf_chunk = kmalloc(chunk, GFP_KERNEL);
988 kfree(tty->write_buf);
989 tty->write_cnt = chunk;
990 tty->write_buf = buf_chunk;
993 /* Do the write .. */
999 if (copy_from_user(tty->write_buf, buf, size))
1001 ret = write(tty, file, tty->write_buf, size);
1010 if (signal_pending(current))
1015 struct inode *inode = file->f_path.dentry->d_inode;
1016 inode->i_mtime = current_fs_time(inode->i_sb);
1020 tty_write_unlock(tty);
1025 * tty_write_message - write a message to a certain tty, not just the console.
1026 * @tty: the destination tty_struct
1027 * @msg: the message to write
1029 * This is used for messages that need to be redirected to a specific tty.
1030 * We don't put it into the syslog queue right now maybe in the future if
1033 * We must still hold the BTM and test the CLOSING flag for the moment.
1036 void tty_write_message(struct tty_struct *tty, char *msg)
1039 mutex_lock(&tty->atomic_write_lock);
1041 if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags)) {
1043 tty->ops->write(tty, msg, strlen(msg));
1046 tty_write_unlock(tty);
1053 * tty_write - write method for tty device file
1054 * @file: tty file pointer
1055 * @buf: user data to write
1056 * @count: bytes to write
1059 * Write data to a tty device via the line discipline.
1062 * Locks the line discipline as required
1063 * Writes to the tty driver are serialized by the atomic_write_lock
1064 * and are then processed in chunks to the device. The line discipline
1065 * write method will not be invoked in parallel for each device.
1068 static ssize_t tty_write(struct file *file, const char __user *buf,
1069 size_t count, loff_t *ppos)
1071 struct tty_struct *tty;
1072 struct inode *inode = file->f_path.dentry->d_inode;
1074 struct tty_ldisc *ld;
1076 tty = file->private_data;
1077 if (tty_paranoia_check(tty, inode, "tty_write"))
1079 if (!tty || !tty->ops->write ||
1080 (test_bit(TTY_IO_ERROR, &tty->flags)))
1082 /* Short term debug to catch buggy drivers */
1083 if (tty->ops->write_room == NULL)
1084 printk(KERN_ERR "tty driver %s lacks a write_room method.\n",
1086 ld = tty_ldisc_ref_wait(tty);
1087 if (!ld->ops->write)
1090 ret = do_tty_write(ld->ops->write, tty, file, buf, count);
1091 tty_ldisc_deref(ld);
1095 ssize_t redirected_tty_write(struct file *file, const char __user *buf,
1096 size_t count, loff_t *ppos)
1098 struct file *p = NULL;
1100 spin_lock(&redirect_lock);
1105 spin_unlock(&redirect_lock);
1109 res = vfs_write(p, buf, count, &p->f_pos);
1113 return tty_write(file, buf, count, ppos);
1116 static char ptychar[] = "pqrstuvwxyzabcde";
1119 * pty_line_name - generate name for a pty
1120 * @driver: the tty driver in use
1121 * @index: the minor number
1122 * @p: output buffer of at least 6 bytes
1124 * Generate a name from a driver reference and write it to the output
1129 static void pty_line_name(struct tty_driver *driver, int index, char *p)
1131 int i = index + driver->name_base;
1132 /* ->name is initialized to "ttyp", but "tty" is expected */
1133 sprintf(p, "%s%c%x",
1134 driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name,
1135 ptychar[i >> 4 & 0xf], i & 0xf);
1139 * tty_line_name - generate name for a tty
1140 * @driver: the tty driver in use
1141 * @index: the minor number
1142 * @p: output buffer of at least 7 bytes
1144 * Generate a name from a driver reference and write it to the output
1149 static void tty_line_name(struct tty_driver *driver, int index, char *p)
1151 sprintf(p, "%s%d", driver->name, index + driver->name_base);
1155 * tty_driver_lookup_tty() - find an existing tty, if any
1156 * @driver: the driver for the tty
1157 * @idx: the minor number
1159 * Return the tty, if found or ERR_PTR() otherwise.
1161 * Locking: tty_mutex must be held. If tty is found, the mutex must
1162 * be held until the 'fast-open' is also done. Will change once we
1163 * have refcounting in the driver and per driver locking
1165 static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver,
1166 struct inode *inode, int idx)
1168 struct tty_struct *tty;
1170 if (driver->ops->lookup)
1171 return driver->ops->lookup(driver, inode, idx);
1173 tty = driver->ttys[idx];
1178 * tty_init_termios - helper for termios setup
1179 * @tty: the tty to set up
1181 * Initialise the termios structures for this tty. Thus runs under
1182 * the tty_mutex currently so we can be relaxed about ordering.
1185 int tty_init_termios(struct tty_struct *tty)
1187 struct ktermios *tp;
1188 int idx = tty->index;
1190 tp = tty->driver->termios[idx];
1192 tp = kzalloc(sizeof(struct ktermios[2]), GFP_KERNEL);
1195 memcpy(tp, &tty->driver->init_termios,
1196 sizeof(struct ktermios));
1197 tty->driver->termios[idx] = tp;
1200 tty->termios_locked = tp + 1;
1202 /* Compatibility until drivers always set this */
1203 tty->termios->c_ispeed = tty_termios_input_baud_rate(tty->termios);
1204 tty->termios->c_ospeed = tty_termios_baud_rate(tty->termios);
1207 EXPORT_SYMBOL_GPL(tty_init_termios);
1210 * tty_driver_install_tty() - install a tty entry in the driver
1211 * @driver: the driver for the tty
1214 * Install a tty object into the driver tables. The tty->index field
1215 * will be set by the time this is called. This method is responsible
1216 * for ensuring any need additional structures are allocated and
1219 * Locking: tty_mutex for now
1221 static int tty_driver_install_tty(struct tty_driver *driver,
1222 struct tty_struct *tty)
1224 int idx = tty->index;
1227 if (driver->ops->install) {
1228 ret = driver->ops->install(driver, tty);
1232 if (tty_init_termios(tty) == 0) {
1233 tty_driver_kref_get(driver);
1235 driver->ttys[idx] = tty;
1242 * tty_driver_remove_tty() - remove a tty from the driver tables
1243 * @driver: the driver for the tty
1244 * @idx: the minor number
1246 * Remvoe a tty object from the driver tables. The tty->index field
1247 * will be set by the time this is called.
1249 * Locking: tty_mutex for now
1251 static void tty_driver_remove_tty(struct tty_driver *driver,
1252 struct tty_struct *tty)
1254 if (driver->ops->remove)
1255 driver->ops->remove(driver, tty);
1257 driver->ttys[tty->index] = NULL;
1261 * tty_reopen() - fast re-open of an open tty
1262 * @tty - the tty to open
1264 * Return 0 on success, -errno on error.
1266 * Locking: tty_mutex must be held from the time the tty was found
1267 * till this open completes.
1269 static int tty_reopen(struct tty_struct *tty)
1271 struct tty_driver *driver = tty->driver;
1273 if (test_bit(TTY_CLOSING, &tty->flags))
1276 if (driver->type == TTY_DRIVER_TYPE_PTY &&
1277 driver->subtype == PTY_TYPE_MASTER) {
1279 * special case for PTY masters: only one open permitted,
1280 * and the slave side open count is incremented as well.
1288 tty->driver = driver; /* N.B. why do this every time?? */
1290 mutex_lock(&tty->ldisc_mutex);
1291 WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
1292 mutex_unlock(&tty->ldisc_mutex);
1298 * tty_init_dev - initialise a tty device
1299 * @driver: tty driver we are opening a device on
1300 * @idx: device index
1301 * @ret_tty: returned tty structure
1302 * @first_ok: ok to open a new device (used by ptmx)
1304 * Prepare a tty device. This may not be a "new" clean device but
1305 * could also be an active device. The pty drivers require special
1306 * handling because of this.
1309 * The function is called under the tty_mutex, which
1310 * protects us from the tty struct or driver itself going away.
1312 * On exit the tty device has the line discipline attached and
1313 * a reference count of 1. If a pair was created for pty/tty use
1314 * and the other was a pty master then it too has a reference count of 1.
1316 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1317 * failed open. The new code protects the open with a mutex, so it's
1318 * really quite straightforward. The mutex locking can probably be
1319 * relaxed for the (most common) case of reopening a tty.
1322 struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
1325 struct tty_struct *tty;
1328 /* Check if pty master is being opened multiple times */
1329 if (driver->subtype == PTY_TYPE_MASTER &&
1330 (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
1331 return ERR_PTR(-EIO);
1335 * First time open is complex, especially for PTY devices.
1336 * This code guarantees that either everything succeeds and the
1337 * TTY is ready for operation, or else the table slots are vacated
1338 * and the allocated memory released. (Except that the termios
1339 * and locked termios may be retained.)
1342 if (!try_module_get(driver->owner))
1343 return ERR_PTR(-ENODEV);
1345 tty = alloc_tty_struct();
1348 initialize_tty_struct(tty, driver, idx);
1350 retval = tty_driver_install_tty(driver, tty);
1352 free_tty_struct(tty);
1353 module_put(driver->owner);
1354 return ERR_PTR(retval);
1358 * Structures all installed ... call the ldisc open routines.
1359 * If we fail here just call release_tty to clean up. No need
1360 * to decrement the use counts, as release_tty doesn't care.
1362 retval = tty_ldisc_setup(tty, tty->link);
1364 goto release_mem_out;
1368 module_put(driver->owner);
1369 return ERR_PTR(-ENOMEM);
1371 /* call the tty release_tty routine to clean out this slot */
1373 if (printk_ratelimit())
1374 printk(KERN_INFO "tty_init_dev: ldisc open failed, "
1375 "clearing slot %d\n", idx);
1376 release_tty(tty, idx);
1377 return ERR_PTR(retval);
1380 void tty_free_termios(struct tty_struct *tty)
1382 struct ktermios *tp;
1383 int idx = tty->index;
1384 /* Kill this flag and push into drivers for locking etc */
1385 if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
1386 /* FIXME: Locking on ->termios array */
1388 tty->driver->termios[idx] = NULL;
1392 EXPORT_SYMBOL(tty_free_termios);
1394 void tty_shutdown(struct tty_struct *tty)
1396 tty_driver_remove_tty(tty->driver, tty);
1397 tty_free_termios(tty);
1399 EXPORT_SYMBOL(tty_shutdown);
1402 * release_one_tty - release tty structure memory
1403 * @kref: kref of tty we are obliterating
1405 * Releases memory associated with a tty structure, and clears out the
1406 * driver table slots. This function is called when a device is no longer
1407 * in use. It also gets called when setup of a device fails.
1410 * tty_mutex - sometimes only
1411 * takes the file list lock internally when working on the list
1412 * of ttys that the driver keeps.
1414 * This method gets called from a work queue so that the driver private
1415 * cleanup ops can sleep (needed for USB at least)
1417 static void release_one_tty(struct work_struct *work)
1419 struct tty_struct *tty =
1420 container_of(work, struct tty_struct, hangup_work);
1421 struct tty_driver *driver = tty->driver;
1423 if (tty->ops->cleanup)
1424 tty->ops->cleanup(tty);
1427 tty_driver_kref_put(driver);
1428 module_put(driver->owner);
1430 spin_lock(&tty_files_lock);
1431 list_del_init(&tty->tty_files);
1432 spin_unlock(&tty_files_lock);
1435 put_pid(tty->session);
1436 free_tty_struct(tty);
1439 static void queue_release_one_tty(struct kref *kref)
1441 struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
1443 if (tty->ops->shutdown)
1444 tty->ops->shutdown(tty);
1448 /* The hangup queue is now free so we can reuse it rather than
1449 waste a chunk of memory for each port */
1450 INIT_WORK(&tty->hangup_work, release_one_tty);
1451 schedule_work(&tty->hangup_work);
1455 * tty_kref_put - release a tty kref
1458 * Release a reference to a tty device and if need be let the kref
1459 * layer destruct the object for us
1462 void tty_kref_put(struct tty_struct *tty)
1465 kref_put(&tty->kref, queue_release_one_tty);
1467 EXPORT_SYMBOL(tty_kref_put);
1470 * release_tty - release tty structure memory
1472 * Release both @tty and a possible linked partner (think pty pair),
1473 * and decrement the refcount of the backing module.
1476 * tty_mutex - sometimes only
1477 * takes the file list lock internally when working on the list
1478 * of ttys that the driver keeps.
1479 * FIXME: should we require tty_mutex is held here ??
1482 static void release_tty(struct tty_struct *tty, int idx)
1484 /* This should always be true but check for the moment */
1485 WARN_ON(tty->index != idx);
1488 tty_kref_put(tty->link);
1493 * tty_release - vfs callback for close
1494 * @inode: inode of tty
1495 * @filp: file pointer for handle to tty
1497 * Called the last time each file handle is closed that references
1498 * this tty. There may however be several such references.
1501 * Takes bkl. See tty_release_dev
1503 * Even releasing the tty structures is a tricky business.. We have
1504 * to be very careful that the structures are all released at the
1505 * same time, as interrupts might otherwise get the wrong pointers.
1507 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1508 * lead to double frees or releasing memory still in use.
1511 int tty_release(struct inode *inode, struct file *filp)
1513 struct tty_struct *tty, *o_tty;
1514 int pty_master, tty_closing, o_tty_closing, do_sleep;
1519 tty = filp->private_data;
1520 if (tty_paranoia_check(tty, inode, "tty_release_dev"))
1524 check_tty_count(tty, "tty_release_dev");
1526 __tty_fasync(-1, filp, 0);
1529 pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1530 tty->driver->subtype == PTY_TYPE_MASTER);
1531 devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0;
1534 #ifdef TTY_PARANOIA_CHECK
1535 if (idx < 0 || idx >= tty->driver->num) {
1536 printk(KERN_DEBUG "tty_release_dev: bad idx when trying to "
1537 "free (%s)\n", tty->name);
1542 if (tty != tty->driver->ttys[idx]) {
1544 printk(KERN_DEBUG "tty_release_dev: driver.table[%d] not tty "
1545 "for (%s)\n", idx, tty->name);
1548 if (tty->termios != tty->driver->termios[idx]) {
1550 printk(KERN_DEBUG "tty_release_dev: driver.termios[%d] not termios "
1558 #ifdef TTY_DEBUG_HANGUP
1559 printk(KERN_DEBUG "tty_release_dev of %s (tty count=%d)...",
1560 tty_name(tty, buf), tty->count);
1563 #ifdef TTY_PARANOIA_CHECK
1564 if (tty->driver->other &&
1565 !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) {
1566 if (o_tty != tty->driver->other->ttys[idx]) {
1568 printk(KERN_DEBUG "tty_release_dev: other->table[%d] "
1569 "not o_tty for (%s)\n",
1573 if (o_tty->termios != tty->driver->other->termios[idx]) {
1575 printk(KERN_DEBUG "tty_release_dev: other->termios[%d] "
1576 "not o_termios for (%s)\n",
1580 if (o_tty->link != tty) {
1582 printk(KERN_DEBUG "tty_release_dev: bad pty pointers\n");
1587 if (tty->ops->close)
1588 tty->ops->close(tty, filp);
1592 * Sanity check: if tty->count is going to zero, there shouldn't be
1593 * any waiters on tty->read_wait or tty->write_wait. We test the
1594 * wait queues and kick everyone out _before_ actually starting to
1595 * close. This ensures that we won't block while releasing the tty
1598 * The test for the o_tty closing is necessary, since the master and
1599 * slave sides may close in any order. If the slave side closes out
1600 * first, its count will be one, since the master side holds an open.
1601 * Thus this test wouldn't be triggered at the time the slave closes,
1604 * Note that it's possible for the tty to be opened again while we're
1605 * flushing out waiters. By recalculating the closing flags before
1606 * each iteration we avoid any problems.
1609 /* Guard against races with tty->count changes elsewhere and
1610 opens on /dev/tty */
1612 mutex_lock(&tty_mutex);
1614 tty_closing = tty->count <= 1;
1615 o_tty_closing = o_tty &&
1616 (o_tty->count <= (pty_master ? 1 : 0));
1620 if (waitqueue_active(&tty->read_wait)) {
1621 wake_up_poll(&tty->read_wait, POLLIN);
1624 if (waitqueue_active(&tty->write_wait)) {
1625 wake_up_poll(&tty->write_wait, POLLOUT);
1629 if (o_tty_closing) {
1630 if (waitqueue_active(&o_tty->read_wait)) {
1631 wake_up_poll(&o_tty->read_wait, POLLIN);
1634 if (waitqueue_active(&o_tty->write_wait)) {
1635 wake_up_poll(&o_tty->write_wait, POLLOUT);
1642 printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue "
1643 "active!\n", tty_name(tty, buf));
1645 mutex_unlock(&tty_mutex);
1650 * The closing flags are now consistent with the open counts on
1651 * both sides, and we've completed the last operation that could
1652 * block, so it's safe to proceed with closing.
1655 if (--o_tty->count < 0) {
1656 printk(KERN_WARNING "tty_release_dev: bad pty slave count "
1658 o_tty->count, tty_name(o_tty, buf));
1662 if (--tty->count < 0) {
1663 printk(KERN_WARNING "tty_release_dev: bad tty->count (%d) for %s\n",
1664 tty->count, tty_name(tty, buf));
1669 * We've decremented tty->count, so we need to remove this file
1670 * descriptor off the tty->tty_files list; this serves two
1672 * - check_tty_count sees the correct number of file descriptors
1673 * associated with this tty.
1674 * - do_tty_hangup no longer sees this file descriptor as
1675 * something that needs to be handled for hangups.
1677 spin_lock(&tty_files_lock);
1678 BUG_ON(list_empty(&filp->f_u.fu_list));
1679 list_del_init(&filp->f_u.fu_list);
1680 spin_unlock(&tty_files_lock);
1681 filp->private_data = NULL;
1684 * Perform some housekeeping before deciding whether to return.
1686 * Set the TTY_CLOSING flag if this was the last open. In the
1687 * case of a pty we may have to wait around for the other side
1688 * to close, and TTY_CLOSING makes sure we can't be reopened.
1691 set_bit(TTY_CLOSING, &tty->flags);
1693 set_bit(TTY_CLOSING, &o_tty->flags);
1696 * If _either_ side is closing, make sure there aren't any
1697 * processes that still think tty or o_tty is their controlling
1700 if (tty_closing || o_tty_closing) {
1701 read_lock(&tasklist_lock);
1702 session_clear_tty(tty->session);
1704 session_clear_tty(o_tty->session);
1705 read_unlock(&tasklist_lock);
1708 mutex_unlock(&tty_mutex);
1710 /* check whether both sides are closing ... */
1711 if (!tty_closing || (o_tty && !o_tty_closing)) {
1716 #ifdef TTY_DEBUG_HANGUP
1717 printk(KERN_DEBUG "freeing tty structure...");
1720 * Ask the line discipline code to release its structures
1722 tty_ldisc_release(tty, o_tty);
1724 * The release_tty function takes care of the details of clearing
1725 * the slots and preserving the termios structure.
1727 release_tty(tty, idx);
1729 /* Make this pty number available for reallocation */
1731 devpts_kill_index(inode, idx);
1737 * tty_open - open a tty device
1738 * @inode: inode of device file
1739 * @filp: file pointer to tty
1741 * tty_open and tty_release keep up the tty count that contains the
1742 * number of opens done on a tty. We cannot use the inode-count, as
1743 * different inodes might point to the same tty.
1745 * Open-counting is needed for pty masters, as well as for keeping
1746 * track of serial lines: DTR is dropped when the last close happens.
1747 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1749 * The termios state of a pty is reset on first open so that
1750 * settings don't persist across reuse.
1752 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1753 * tty->count should protect the rest.
1754 * ->siglock protects ->signal/->sighand
1757 static int tty_open(struct inode *inode, struct file *filp)
1759 struct tty_struct *tty = NULL;
1761 struct tty_driver *driver;
1763 dev_t device = inode->i_rdev;
1764 unsigned saved_flags = filp->f_flags;
1766 nonseekable_open(inode, filp);
1769 noctty = filp->f_flags & O_NOCTTY;
1773 mutex_lock(&tty_mutex);
1776 if (device == MKDEV(TTYAUX_MAJOR, 0)) {
1777 tty = get_current_tty();
1780 mutex_unlock(&tty_mutex);
1783 driver = tty_driver_kref_get(tty->driver);
1785 filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
1787 /* FIXME: Should we take a driver reference ? */
1792 if (device == MKDEV(TTY_MAJOR, 0)) {
1793 extern struct tty_driver *console_driver;
1794 driver = tty_driver_kref_get(console_driver);
1800 if (device == MKDEV(TTYAUX_MAJOR, 1)) {
1801 struct tty_driver *console_driver = console_device(&index);
1802 if (console_driver) {
1803 driver = tty_driver_kref_get(console_driver);
1805 /* Don't let /dev/console block */
1806 filp->f_flags |= O_NONBLOCK;
1812 mutex_unlock(&tty_mutex);
1816 driver = get_tty_driver(device, &index);
1819 mutex_unlock(&tty_mutex);
1824 /* check whether we're reopening an existing tty */
1825 tty = tty_driver_lookup_tty(driver, inode, index);
1829 mutex_unlock(&tty_mutex);
1830 return PTR_ERR(tty);
1835 retval = tty_reopen(tty);
1837 tty = ERR_PTR(retval);
1839 tty = tty_init_dev(driver, index, 0);
1841 mutex_unlock(&tty_mutex);
1842 tty_driver_kref_put(driver);
1845 return PTR_ERR(tty);
1848 filp->private_data = tty;
1849 BUG_ON(list_empty(&filp->f_u.fu_list));
1850 file_sb_list_del(filp); /* __dentry_open has put it on the sb list */
1851 spin_lock(&tty_files_lock);
1852 list_add(&filp->f_u.fu_list, &tty->tty_files);
1853 spin_unlock(&tty_files_lock);
1854 check_tty_count(tty, "tty_open");
1855 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
1856 tty->driver->subtype == PTY_TYPE_MASTER)
1858 #ifdef TTY_DEBUG_HANGUP
1859 printk(KERN_DEBUG "opening %s...", tty->name);
1863 retval = tty->ops->open(tty, filp);
1867 filp->f_flags = saved_flags;
1869 if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) &&
1870 !capable(CAP_SYS_ADMIN))
1874 #ifdef TTY_DEBUG_HANGUP
1875 printk(KERN_DEBUG "error %d in opening %s...", retval,
1878 tty_unlock(); /* need to call tty_release without BTM */
1879 tty_release(inode, filp);
1880 if (retval != -ERESTARTSYS)
1883 if (signal_pending(current))
1888 * Need to reset f_op in case a hangup happened.
1891 if (filp->f_op == &hung_up_tty_fops)
1892 filp->f_op = &tty_fops;
1899 mutex_lock(&tty_mutex);
1901 spin_lock_irq(¤t->sighand->siglock);
1903 current->signal->leader &&
1904 !current->signal->tty &&
1905 tty->session == NULL)
1906 __proc_set_tty(current, tty);
1907 spin_unlock_irq(¤t->sighand->siglock);
1909 mutex_unlock(&tty_mutex);
1916 * tty_poll - check tty status
1917 * @filp: file being polled
1918 * @wait: poll wait structures to update
1920 * Call the line discipline polling method to obtain the poll
1921 * status of the device.
1923 * Locking: locks called line discipline but ldisc poll method
1924 * may be re-entered freely by other callers.
1927 static unsigned int tty_poll(struct file *filp, poll_table *wait)
1929 struct tty_struct *tty;
1930 struct tty_ldisc *ld;
1933 tty = filp->private_data;
1934 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_poll"))
1937 ld = tty_ldisc_ref_wait(tty);
1939 ret = (ld->ops->poll)(tty, filp, wait);
1940 tty_ldisc_deref(ld);
1944 static int __tty_fasync(int fd, struct file *filp, int on)
1946 struct tty_struct *tty;
1947 unsigned long flags;
1950 tty = filp->private_data;
1951 if (tty_paranoia_check(tty, filp->f_path.dentry->d_inode, "tty_fasync"))
1954 retval = fasync_helper(fd, filp, on, &tty->fasync);
1961 if (!waitqueue_active(&tty->read_wait))
1962 tty->minimum_to_wake = 1;
1963 spin_lock_irqsave(&tty->ctrl_lock, flags);
1966 type = PIDTYPE_PGID;
1968 pid = task_pid(current);
1972 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
1973 retval = __f_setown(filp, pid, type, 0);
1978 if (!tty->fasync && !waitqueue_active(&tty->read_wait))
1979 tty->minimum_to_wake = N_TTY_BUF_SIZE;
1986 static int tty_fasync(int fd, struct file *filp, int on)
1990 retval = __tty_fasync(fd, filp, on);
1996 * tiocsti - fake input character
1997 * @tty: tty to fake input into
1998 * @p: pointer to character
2000 * Fake input to a tty device. Does the necessary locking and
2003 * FIXME: does not honour flow control ??
2006 * Called functions take tty_ldisc_lock
2007 * current->signal->tty check is safe without locks
2009 * FIXME: may race normal receive processing
2012 static int tiocsti(struct tty_struct *tty, char __user *p)
2015 struct tty_ldisc *ld;
2017 if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN))
2019 if (get_user(ch, p))
2021 tty_audit_tiocsti(tty, ch);
2022 ld = tty_ldisc_ref_wait(tty);
2023 ld->ops->receive_buf(tty, &ch, &mbz, 1);
2024 tty_ldisc_deref(ld);
2029 * tiocgwinsz - implement window query ioctl
2031 * @arg: user buffer for result
2033 * Copies the kernel idea of the window size into the user buffer.
2035 * Locking: tty->termios_mutex is taken to ensure the winsize data
2039 static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
2043 mutex_lock(&tty->termios_mutex);
2044 err = copy_to_user(arg, &tty->winsize, sizeof(*arg));
2045 mutex_unlock(&tty->termios_mutex);
2047 return err ? -EFAULT: 0;
2051 * tty_do_resize - resize event
2052 * @tty: tty being resized
2053 * @rows: rows (character)
2054 * @cols: cols (character)
2056 * Update the termios variables and send the necessary signals to
2057 * peform a terminal resize correctly
2060 int tty_do_resize(struct tty_struct *tty, struct winsize *ws)
2063 unsigned long flags;
2066 mutex_lock(&tty->termios_mutex);
2067 if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
2069 /* Get the PID values and reference them so we can
2070 avoid holding the tty ctrl lock while sending signals */
2071 spin_lock_irqsave(&tty->ctrl_lock, flags);
2072 pgrp = get_pid(tty->pgrp);
2073 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2076 kill_pgrp(pgrp, SIGWINCH, 1);
2081 mutex_unlock(&tty->termios_mutex);
2086 * tiocswinsz - implement window size set ioctl
2087 * @tty; tty side of tty
2088 * @arg: user buffer for result
2090 * Copies the user idea of the window size to the kernel. Traditionally
2091 * this is just advisory information but for the Linux console it
2092 * actually has driver level meaning and triggers a VC resize.
2095 * Driver dependant. The default do_resize method takes the
2096 * tty termios mutex and ctrl_lock. The console takes its own lock
2097 * then calls into the default method.
2100 static int tiocswinsz(struct tty_struct *tty, struct winsize __user *arg)
2102 struct winsize tmp_ws;
2103 if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
2106 if (tty->ops->resize)
2107 return tty->ops->resize(tty, &tmp_ws);
2109 return tty_do_resize(tty, &tmp_ws);
2113 * tioccons - allow admin to move logical console
2114 * @file: the file to become console
2116 * Allow the adminstrator to move the redirected console device
2118 * Locking: uses redirect_lock to guard the redirect information
2121 static int tioccons(struct file *file)
2123 if (!capable(CAP_SYS_ADMIN))
2125 if (file->f_op->write == redirected_tty_write) {
2127 spin_lock(&redirect_lock);
2130 spin_unlock(&redirect_lock);
2135 spin_lock(&redirect_lock);
2137 spin_unlock(&redirect_lock);
2142 spin_unlock(&redirect_lock);
2147 * fionbio - non blocking ioctl
2148 * @file: file to set blocking value
2149 * @p: user parameter
2151 * Historical tty interfaces had a blocking control ioctl before
2152 * the generic functionality existed. This piece of history is preserved
2153 * in the expected tty API of posix OS's.
2155 * Locking: none, the open file handle ensures it won't go away.
2158 static int fionbio(struct file *file, int __user *p)
2162 if (get_user(nonblock, p))
2165 spin_lock(&file->f_lock);
2167 file->f_flags |= O_NONBLOCK;
2169 file->f_flags &= ~O_NONBLOCK;
2170 spin_unlock(&file->f_lock);
2175 * tiocsctty - set controlling tty
2176 * @tty: tty structure
2177 * @arg: user argument
2179 * This ioctl is used to manage job control. It permits a session
2180 * leader to set this tty as the controlling tty for the session.
2183 * Takes tty_mutex() to protect tty instance
2184 * Takes tasklist_lock internally to walk sessions
2185 * Takes ->siglock() when updating signal->tty
2188 static int tiocsctty(struct tty_struct *tty, int arg)
2191 if (current->signal->leader && (task_session(current) == tty->session))
2194 mutex_lock(&tty_mutex);
2196 * The process must be a session leader and
2197 * not have a controlling tty already.
2199 if (!current->signal->leader || current->signal->tty) {
2206 * This tty is already the controlling
2207 * tty for another session group!
2209 if (arg == 1 && capable(CAP_SYS_ADMIN)) {
2213 read_lock(&tasklist_lock);
2214 session_clear_tty(tty->session);
2215 read_unlock(&tasklist_lock);
2221 proc_set_tty(current, tty);
2223 mutex_unlock(&tty_mutex);
2228 * tty_get_pgrp - return a ref counted pgrp pid
2231 * Returns a refcounted instance of the pid struct for the process
2232 * group controlling the tty.
2235 struct pid *tty_get_pgrp(struct tty_struct *tty)
2237 unsigned long flags;
2240 spin_lock_irqsave(&tty->ctrl_lock, flags);
2241 pgrp = get_pid(tty->pgrp);
2242 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2246 EXPORT_SYMBOL_GPL(tty_get_pgrp);
2249 * tiocgpgrp - get process group
2250 * @tty: tty passed by user
2251 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2254 * Obtain the process group of the tty. If there is no process group
2257 * Locking: none. Reference to current->signal->tty is safe.
2260 static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2265 * (tty == real_tty) is a cheap way of
2266 * testing if the tty is NOT a master pty.
2268 if (tty == real_tty && current->signal->tty != real_tty)
2270 pid = tty_get_pgrp(real_tty);
2271 ret = put_user(pid_vnr(pid), p);
2277 * tiocspgrp - attempt to set process group
2278 * @tty: tty passed by user
2279 * @real_tty: tty side device matching tty passed by user
2282 * Set the process group of the tty to the session passed. Only
2283 * permitted where the tty session is our session.
2285 * Locking: RCU, ctrl lock
2288 static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2292 int retval = tty_check_change(real_tty);
2293 unsigned long flags;
2299 if (!current->signal->tty ||
2300 (current->signal->tty != real_tty) ||
2301 (real_tty->session != task_session(current)))
2303 if (get_user(pgrp_nr, p))
2308 pgrp = find_vpid(pgrp_nr);
2313 if (session_of_pgrp(pgrp) != task_session(current))
2316 spin_lock_irqsave(&tty->ctrl_lock, flags);
2317 put_pid(real_tty->pgrp);
2318 real_tty->pgrp = get_pid(pgrp);
2319 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
2326 * tiocgsid - get session id
2327 * @tty: tty passed by user
2328 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2329 * @p: pointer to returned session id
2331 * Obtain the session id of the tty. If there is no session
2334 * Locking: none. Reference to current->signal->tty is safe.
2337 static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
2340 * (tty == real_tty) is a cheap way of
2341 * testing if the tty is NOT a master pty.
2343 if (tty == real_tty && current->signal->tty != real_tty)
2345 if (!real_tty->session)
2347 return put_user(pid_vnr(real_tty->session), p);
2351 * tiocsetd - set line discipline
2353 * @p: pointer to user data
2355 * Set the line discipline according to user request.
2357 * Locking: see tty_set_ldisc, this function is just a helper
2360 static int tiocsetd(struct tty_struct *tty, int __user *p)
2365 if (get_user(ldisc, p))
2368 ret = tty_set_ldisc(tty, ldisc);
2374 * send_break - performed time break
2375 * @tty: device to break on
2376 * @duration: timeout in mS
2378 * Perform a timed break on hardware that lacks its own driver level
2379 * timed break functionality.
2382 * atomic_write_lock serializes
2386 static int send_break(struct tty_struct *tty, unsigned int duration)
2390 if (tty->ops->break_ctl == NULL)
2393 if (tty->driver->flags & TTY_DRIVER_HARDWARE_BREAK)
2394 retval = tty->ops->break_ctl(tty, duration);
2396 /* Do the work ourselves */
2397 if (tty_write_lock(tty, 0) < 0)
2399 retval = tty->ops->break_ctl(tty, -1);
2402 if (!signal_pending(current))
2403 msleep_interruptible(duration);
2404 retval = tty->ops->break_ctl(tty, 0);
2406 tty_write_unlock(tty);
2407 if (signal_pending(current))
2414 * tty_tiocmget - get modem status
2416 * @file: user file pointer
2417 * @p: pointer to result
2419 * Obtain the modem status bits from the tty driver if the feature
2420 * is supported. Return -EINVAL if it is not available.
2422 * Locking: none (up to the driver)
2425 static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p)
2427 int retval = -EINVAL;
2429 if (tty->ops->tiocmget) {
2430 retval = tty->ops->tiocmget(tty, file);
2433 retval = put_user(retval, p);
2439 * tty_tiocmset - set modem status
2441 * @file: user file pointer
2442 * @cmd: command - clear bits, set bits or set all
2443 * @p: pointer to desired bits
2445 * Set the modem status bits from the tty driver if the feature
2446 * is supported. Return -EINVAL if it is not available.
2448 * Locking: none (up to the driver)
2451 static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd,
2455 unsigned int set, clear, val;
2457 if (tty->ops->tiocmset == NULL)
2460 retval = get_user(val, p);
2476 set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2477 clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP;
2478 return tty->ops->tiocmset(tty, file, set, clear);
2481 struct tty_struct *tty_pair_get_tty(struct tty_struct *tty)
2483 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2484 tty->driver->subtype == PTY_TYPE_MASTER)
2488 EXPORT_SYMBOL(tty_pair_get_tty);
2490 struct tty_struct *tty_pair_get_pty(struct tty_struct *tty)
2492 if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
2493 tty->driver->subtype == PTY_TYPE_MASTER)
2497 EXPORT_SYMBOL(tty_pair_get_pty);
2500 * Split this up, as gcc can choke on it otherwise..
2502 long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
2504 struct tty_struct *tty, *real_tty;
2505 void __user *p = (void __user *)arg;
2507 struct tty_ldisc *ld;
2508 struct inode *inode = file->f_dentry->d_inode;
2510 tty = file->private_data;
2511 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2514 real_tty = tty_pair_get_tty(tty);
2517 * Factor out some common prep work
2525 retval = tty_check_change(tty);
2528 if (cmd != TIOCCBRK) {
2529 tty_wait_until_sent(tty, 0);
2530 if (signal_pending(current))
2541 return tiocsti(tty, p);
2543 return tiocgwinsz(real_tty, p);
2545 return tiocswinsz(real_tty, p);
2547 return real_tty != tty ? -EINVAL : tioccons(file);
2549 return fionbio(file, p);
2551 set_bit(TTY_EXCLUSIVE, &tty->flags);
2554 clear_bit(TTY_EXCLUSIVE, &tty->flags);
2557 if (current->signal->tty != tty)
2562 return tiocsctty(tty, arg);
2564 return tiocgpgrp(tty, real_tty, p);
2566 return tiocspgrp(tty, real_tty, p);
2568 return tiocgsid(tty, real_tty, p);
2570 return put_user(tty->ldisc->ops->num, (int __user *)p);
2572 return tiocsetd(tty, p);
2576 case TIOCSBRK: /* Turn break on, unconditionally */
2577 if (tty->ops->break_ctl)
2578 return tty->ops->break_ctl(tty, -1);
2580 case TIOCCBRK: /* Turn break off, unconditionally */
2581 if (tty->ops->break_ctl)
2582 return tty->ops->break_ctl(tty, 0);
2584 case TCSBRK: /* SVID version: non-zero arg --> no break */
2585 /* non-zero arg means wait for all output data
2586 * to be sent (performed above) but don't send break.
2587 * This is used by the tcdrain() termios function.
2590 return send_break(tty, 250);
2592 case TCSBRKP: /* support for POSIX tcsendbreak() */
2593 return send_break(tty, arg ? arg*100 : 250);
2596 return tty_tiocmget(tty, file, p);
2600 return tty_tiocmset(tty, file, cmd, p);
2605 /* flush tty buffer and allow ldisc to process ioctl */
2606 tty_buffer_flush(tty);
2611 if (tty->ops->ioctl) {
2612 retval = (tty->ops->ioctl)(tty, file, cmd, arg);
2613 if (retval != -ENOIOCTLCMD)
2616 ld = tty_ldisc_ref_wait(tty);
2618 if (ld->ops->ioctl) {
2619 retval = ld->ops->ioctl(tty, file, cmd, arg);
2620 if (retval == -ENOIOCTLCMD)
2623 tty_ldisc_deref(ld);
2627 #ifdef CONFIG_COMPAT
2628 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
2631 struct inode *inode = file->f_dentry->d_inode;
2632 struct tty_struct *tty = file->private_data;
2633 struct tty_ldisc *ld;
2634 int retval = -ENOIOCTLCMD;
2636 if (tty_paranoia_check(tty, inode, "tty_ioctl"))
2639 if (tty->ops->compat_ioctl) {
2640 retval = (tty->ops->compat_ioctl)(tty, file, cmd, arg);
2641 if (retval != -ENOIOCTLCMD)
2645 ld = tty_ldisc_ref_wait(tty);
2646 if (ld->ops->compat_ioctl)
2647 retval = ld->ops->compat_ioctl(tty, file, cmd, arg);
2648 tty_ldisc_deref(ld);
2655 * This implements the "Secure Attention Key" --- the idea is to
2656 * prevent trojan horses by killing all processes associated with this
2657 * tty when the user hits the "Secure Attention Key". Required for
2658 * super-paranoid applications --- see the Orange Book for more details.
2660 * This code could be nicer; ideally it should send a HUP, wait a few
2661 * seconds, then send a INT, and then a KILL signal. But you then
2662 * have to coordinate with the init process, since all processes associated
2663 * with the current tty must be dead before the new getty is allowed
2666 * Now, if it would be correct ;-/ The current code has a nasty hole -
2667 * it doesn't catch files in flight. We may send the descriptor to ourselves
2668 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2670 * Nasty bug: do_SAK is being called in interrupt context. This can
2671 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2673 void __do_SAK(struct tty_struct *tty)
2678 struct task_struct *g, *p;
2679 struct pid *session;
2682 struct fdtable *fdt;
2686 session = tty->session;
2688 tty_ldisc_flush(tty);
2690 tty_driver_flush_buffer(tty);
2692 read_lock(&tasklist_lock);
2693 /* Kill the entire session */
2694 do_each_pid_task(session, PIDTYPE_SID, p) {
2695 printk(KERN_NOTICE "SAK: killed process %d"
2696 " (%s): task_session(p)==tty->session\n",
2697 task_pid_nr(p), p->comm);
2698 send_sig(SIGKILL, p, 1);
2699 } while_each_pid_task(session, PIDTYPE_SID, p);
2700 /* Now kill any processes that happen to have the
2703 do_each_thread(g, p) {
2704 if (p->signal->tty == tty) {
2705 printk(KERN_NOTICE "SAK: killed process %d"
2706 " (%s): task_session(p)==tty->session\n",
2707 task_pid_nr(p), p->comm);
2708 send_sig(SIGKILL, p, 1);
2714 * We don't take a ref to the file, so we must
2715 * hold ->file_lock instead.
2717 spin_lock(&p->files->file_lock);
2718 fdt = files_fdtable(p->files);
2719 for (i = 0; i < fdt->max_fds; i++) {
2720 filp = fcheck_files(p->files, i);
2723 if (filp->f_op->read == tty_read &&
2724 filp->private_data == tty) {
2725 printk(KERN_NOTICE "SAK: killed process %d"
2726 " (%s): fd#%d opened to the tty\n",
2727 task_pid_nr(p), p->comm, i);
2728 force_sig(SIGKILL, p);
2732 spin_unlock(&p->files->file_lock);
2735 } while_each_thread(g, p);
2736 read_unlock(&tasklist_lock);
2740 static void do_SAK_work(struct work_struct *work)
2742 struct tty_struct *tty =
2743 container_of(work, struct tty_struct, SAK_work);
2748 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2749 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2750 * the values which we write to it will be identical to the values which it
2751 * already has. --akpm
2753 void do_SAK(struct tty_struct *tty)
2757 schedule_work(&tty->SAK_work);
2760 EXPORT_SYMBOL(do_SAK);
2763 * initialize_tty_struct
2764 * @tty: tty to initialize
2766 * This subroutine initializes a tty structure that has been newly
2769 * Locking: none - tty in question must not be exposed at this point
2772 void initialize_tty_struct(struct tty_struct *tty,
2773 struct tty_driver *driver, int idx)
2775 memset(tty, 0, sizeof(struct tty_struct));
2776 kref_init(&tty->kref);
2777 tty->magic = TTY_MAGIC;
2778 tty_ldisc_init(tty);
2779 tty->session = NULL;
2781 tty->overrun_time = jiffies;
2782 tty->buf.head = tty->buf.tail = NULL;
2783 tty_buffer_init(tty);
2784 mutex_init(&tty->termios_mutex);
2785 mutex_init(&tty->ldisc_mutex);
2786 init_waitqueue_head(&tty->write_wait);
2787 init_waitqueue_head(&tty->read_wait);
2788 INIT_WORK(&tty->hangup_work, do_tty_hangup);
2789 mutex_init(&tty->atomic_read_lock);
2790 mutex_init(&tty->atomic_write_lock);
2791 mutex_init(&tty->output_lock);
2792 mutex_init(&tty->echo_lock);
2793 spin_lock_init(&tty->read_lock);
2794 spin_lock_init(&tty->ctrl_lock);
2795 INIT_LIST_HEAD(&tty->tty_files);
2796 INIT_WORK(&tty->SAK_work, do_SAK_work);
2798 tty->driver = driver;
2799 tty->ops = driver->ops;
2801 tty_line_name(driver, idx, tty->name);
2805 * tty_put_char - write one character to a tty
2809 * Write one byte to the tty using the provided put_char method
2810 * if present. Returns the number of characters successfully output.
2812 * Note: the specific put_char operation in the driver layer may go
2813 * away soon. Don't call it directly, use this method
2816 int tty_put_char(struct tty_struct *tty, unsigned char ch)
2818 if (tty->ops->put_char)
2819 return tty->ops->put_char(tty, ch);
2820 return tty->ops->write(tty, &ch, 1);
2822 EXPORT_SYMBOL_GPL(tty_put_char);
2824 struct class *tty_class;
2827 * tty_register_device - register a tty device
2828 * @driver: the tty driver that describes the tty device
2829 * @index: the index in the tty driver for this tty device
2830 * @device: a struct device that is associated with this tty device.
2831 * This field is optional, if there is no known struct device
2832 * for this tty device it can be set to NULL safely.
2834 * Returns a pointer to the struct device for this tty device
2835 * (or ERR_PTR(-EFOO) on error).
2837 * This call is required to be made to register an individual tty device
2838 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2839 * that bit is not set, this function should not be called by a tty
2845 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
2846 struct device *device)
2849 dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
2851 if (index >= driver->num) {
2852 printk(KERN_ERR "Attempt to register invalid tty line number "
2854 return ERR_PTR(-EINVAL);
2857 if (driver->type == TTY_DRIVER_TYPE_PTY)
2858 pty_line_name(driver, index, name);
2860 tty_line_name(driver, index, name);
2862 return device_create(tty_class, device, dev, NULL, name);
2864 EXPORT_SYMBOL(tty_register_device);
2867 * tty_unregister_device - unregister a tty device
2868 * @driver: the tty driver that describes the tty device
2869 * @index: the index in the tty driver for this tty device
2871 * If a tty device is registered with a call to tty_register_device() then
2872 * this function must be called when the tty device is gone.
2877 void tty_unregister_device(struct tty_driver *driver, unsigned index)
2879 device_destroy(tty_class,
2880 MKDEV(driver->major, driver->minor_start) + index);
2882 EXPORT_SYMBOL(tty_unregister_device);
2884 struct tty_driver *alloc_tty_driver(int lines)
2886 struct tty_driver *driver;
2888 driver = kzalloc(sizeof(struct tty_driver), GFP_KERNEL);
2890 kref_init(&driver->kref);
2891 driver->magic = TTY_DRIVER_MAGIC;
2892 driver->num = lines;
2893 /* later we'll move allocation of tables here */
2897 EXPORT_SYMBOL(alloc_tty_driver);
2899 static void destruct_tty_driver(struct kref *kref)
2901 struct tty_driver *driver = container_of(kref, struct tty_driver, kref);
2903 struct ktermios *tp;
2906 if (driver->flags & TTY_DRIVER_INSTALLED) {
2908 * Free the termios and termios_locked structures because
2909 * we don't want to get memory leaks when modular tty
2910 * drivers are removed from the kernel.
2912 for (i = 0; i < driver->num; i++) {
2913 tp = driver->termios[i];
2915 driver->termios[i] = NULL;
2918 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV))
2919 tty_unregister_device(driver, i);
2922 proc_tty_unregister_driver(driver);
2923 driver->ttys = NULL;
2924 driver->termios = NULL;
2926 cdev_del(&driver->cdev);
2931 void tty_driver_kref_put(struct tty_driver *driver)
2933 kref_put(&driver->kref, destruct_tty_driver);
2935 EXPORT_SYMBOL(tty_driver_kref_put);
2937 void tty_set_operations(struct tty_driver *driver,
2938 const struct tty_operations *op)
2942 EXPORT_SYMBOL(tty_set_operations);
2944 void put_tty_driver(struct tty_driver *d)
2946 tty_driver_kref_put(d);
2948 EXPORT_SYMBOL(put_tty_driver);
2951 * Called by a tty driver to register itself.
2953 int tty_register_driver(struct tty_driver *driver)
2960 if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM) && driver->num) {
2961 p = kzalloc(driver->num * 2 * sizeof(void *), GFP_KERNEL);
2966 if (!driver->major) {
2967 error = alloc_chrdev_region(&dev, driver->minor_start,
2968 driver->num, driver->name);
2970 driver->major = MAJOR(dev);
2971 driver->minor_start = MINOR(dev);
2974 dev = MKDEV(driver->major, driver->minor_start);
2975 error = register_chrdev_region(dev, driver->num, driver->name);
2983 driver->ttys = (struct tty_struct **)p;
2984 driver->termios = (struct ktermios **)(p + driver->num);
2986 driver->ttys = NULL;
2987 driver->termios = NULL;
2990 cdev_init(&driver->cdev, &tty_fops);
2991 driver->cdev.owner = driver->owner;
2992 error = cdev_add(&driver->cdev, dev, driver->num);
2994 unregister_chrdev_region(dev, driver->num);
2995 driver->ttys = NULL;
2996 driver->termios = NULL;
3001 mutex_lock(&tty_mutex);
3002 list_add(&driver->tty_drivers, &tty_drivers);
3003 mutex_unlock(&tty_mutex);
3005 if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) {
3006 for (i = 0; i < driver->num; i++)
3007 tty_register_device(driver, i, NULL);
3009 proc_tty_register_driver(driver);
3010 driver->flags |= TTY_DRIVER_INSTALLED;
3014 EXPORT_SYMBOL(tty_register_driver);
3017 * Called by a tty driver to unregister itself.
3019 int tty_unregister_driver(struct tty_driver *driver)
3023 if (driver->refcount)
3026 unregister_chrdev_region(MKDEV(driver->major, driver->minor_start),
3028 mutex_lock(&tty_mutex);
3029 list_del(&driver->tty_drivers);
3030 mutex_unlock(&tty_mutex);
3034 EXPORT_SYMBOL(tty_unregister_driver);
3036 dev_t tty_devnum(struct tty_struct *tty)
3038 return MKDEV(tty->driver->major, tty->driver->minor_start) + tty->index;
3040 EXPORT_SYMBOL(tty_devnum);
3042 void proc_clear_tty(struct task_struct *p)
3044 unsigned long flags;
3045 struct tty_struct *tty;
3046 spin_lock_irqsave(&p->sighand->siglock, flags);
3047 tty = p->signal->tty;
3048 p->signal->tty = NULL;
3049 spin_unlock_irqrestore(&p->sighand->siglock, flags);
3053 /* Called under the sighand lock */
3055 static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3058 unsigned long flags;
3059 /* We should not have a session or pgrp to put here but.... */
3060 spin_lock_irqsave(&tty->ctrl_lock, flags);
3061 put_pid(tty->session);
3063 tty->pgrp = get_pid(task_pgrp(tsk));
3064 spin_unlock_irqrestore(&tty->ctrl_lock, flags);
3065 tty->session = get_pid(task_session(tsk));
3066 if (tsk->signal->tty) {
3067 printk(KERN_DEBUG "tty not NULL!!\n");
3068 tty_kref_put(tsk->signal->tty);
3071 put_pid(tsk->signal->tty_old_pgrp);
3072 tsk->signal->tty = tty_kref_get(tty);
3073 tsk->signal->tty_old_pgrp = NULL;
3076 static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
3078 spin_lock_irq(&tsk->sighand->siglock);
3079 __proc_set_tty(tsk, tty);
3080 spin_unlock_irq(&tsk->sighand->siglock);
3083 struct tty_struct *get_current_tty(void)
3085 struct tty_struct *tty;
3086 unsigned long flags;
3088 spin_lock_irqsave(¤t->sighand->siglock, flags);
3089 tty = tty_kref_get(current->signal->tty);
3090 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
3093 EXPORT_SYMBOL_GPL(get_current_tty);
3095 void tty_default_fops(struct file_operations *fops)
3101 * Initialize the console device. This is called *early*, so
3102 * we can't necessarily depend on lots of kernel help here.
3103 * Just do some early initializations, and do the complex setup
3106 void __init console_init(void)
3110 /* Setup the default TTY line discipline. */
3114 * set up the console device so that later boot sequences can
3115 * inform about problems etc..
3117 call = __con_initcall_start;
3118 while (call < __con_initcall_end) {
3124 static char *tty_devnode(struct device *dev, mode_t *mode)
3128 if (dev->devt == MKDEV(TTYAUX_MAJOR, 0) ||
3129 dev->devt == MKDEV(TTYAUX_MAJOR, 2))
3134 static int __init tty_class_init(void)
3136 tty_class = class_create(THIS_MODULE, "tty");
3137 if (IS_ERR(tty_class))
3138 return PTR_ERR(tty_class);
3139 tty_class->devnode = tty_devnode;
3143 postcore_initcall(tty_class_init);
3145 /* 3/2004 jmc: why do these devices exist? */
3147 static struct cdev tty_cdev, console_cdev;
3150 * Ok, now we can initialize the rest of the tty devices and can count
3151 * on memory allocations, interrupts etc..
3153 int __init tty_init(void)
3155 cdev_init(&tty_cdev, &tty_fops);
3156 if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
3157 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
3158 panic("Couldn't register /dev/tty driver\n");
3159 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
3162 cdev_init(&console_cdev, &console_fops);
3163 if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
3164 register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
3165 panic("Couldn't register /dev/console driver\n");
3166 device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
3170 vty_init(&console_fops);