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 init_dev and 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 #ifdef CONFIG_UNIX98_PTYS
140 extern struct tty_driver
*ptm_driver
; /* Unix98 pty masters; for /dev/ptmx */
141 static int ptmx_open(struct inode
*, struct file
*);
144 static void initialize_tty_struct(struct tty_struct
*tty
);
146 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
147 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
148 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
150 static unsigned int tty_poll(struct file
*, poll_table
*);
151 static int tty_open(struct inode
*, struct file
*);
152 static int tty_release(struct inode
*, struct file
*);
153 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
155 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
158 #define tty_compat_ioctl NULL
160 static int tty_fasync(int fd
, struct file
*filp
, int on
);
161 static void release_tty(struct tty_struct
*tty
, int idx
);
162 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
163 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
166 * alloc_tty_struct - allocate a tty object
168 * Return a new empty tty structure. The data fields have not
169 * been initialized in any way but has been zeroed
174 static struct tty_struct
*alloc_tty_struct(void)
176 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
180 * free_tty_struct - free a disused tty
181 * @tty: tty struct to free
183 * Free the write buffers, tty queue and tty memory itself.
185 * Locking: none. Must be called after tty is definitely unused
188 static inline void free_tty_struct(struct tty_struct
*tty
)
190 kfree(tty
->write_buf
);
191 tty_buffer_free_all(tty
);
195 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
198 * tty_name - return tty naming
199 * @tty: tty structure
200 * @buf: buffer for output
202 * Convert a tty structure into a name. The name reflects the kernel
203 * naming policy and if udev is in use may not reflect user space
208 char *tty_name(struct tty_struct
*tty
, char *buf
)
210 if (!tty
) /* Hmm. NULL pointer. That's fun. */
211 strcpy(buf
, "NULL tty");
213 strcpy(buf
, tty
->name
);
217 EXPORT_SYMBOL(tty_name
);
219 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
222 #ifdef TTY_PARANOIA_CHECK
225 "null TTY for (%d:%d) in %s\n",
226 imajor(inode
), iminor(inode
), routine
);
229 if (tty
->magic
!= TTY_MAGIC
) {
231 "bad magic number for tty struct (%d:%d) in %s\n",
232 imajor(inode
), iminor(inode
), routine
);
239 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
241 #ifdef CHECK_TTY_COUNT
246 list_for_each(p
, &tty
->tty_files
) {
250 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
251 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
252 tty
->link
&& tty
->link
->count
)
254 if (tty
->count
!= count
) {
255 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
256 "!= #fd's(%d) in %s\n",
257 tty
->name
, tty
->count
, count
, routine
);
265 * get_tty_driver - find device of a tty
266 * @dev_t: device identifier
267 * @index: returns the index of the tty
269 * This routine returns a tty driver structure, given a device number
270 * and also passes back the index number.
272 * Locking: caller must hold tty_mutex
275 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
277 struct tty_driver
*p
;
279 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
280 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
281 if (device
< base
|| device
>= base
+ p
->num
)
283 *index
= device
- base
;
289 #ifdef CONFIG_CONSOLE_POLL
292 * tty_find_polling_driver - find device of a polled tty
293 * @name: name string to match
294 * @line: pointer to resulting tty line nr
296 * This routine returns a tty driver structure, given a name
297 * and the condition that the tty driver is capable of polled
300 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
302 struct tty_driver
*p
, *res
= NULL
;
307 for (str
= name
; *str
; str
++)
308 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
314 tty_line
= simple_strtoul(str
, &str
, 10);
316 mutex_lock(&tty_mutex
);
317 /* Search through the tty devices to look for a match */
318 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
319 if (strncmp(name
, p
->name
, len
) != 0)
326 if (tty_line
>= 0 && tty_line
<= p
->num
&& p
->ops
&&
327 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, str
)) {
333 mutex_unlock(&tty_mutex
);
337 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
341 * tty_check_change - check for POSIX terminal changes
344 * If we try to write to, or set the state of, a terminal and we're
345 * not in the foreground, send a SIGTTOU. If the signal is blocked or
346 * ignored, go ahead and perform the operation. (POSIX 7.2)
351 int tty_check_change(struct tty_struct
*tty
)
356 if (current
->signal
->tty
!= tty
)
359 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
362 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
365 if (task_pgrp(current
) == tty
->pgrp
)
367 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
368 if (is_ignored(SIGTTOU
))
370 if (is_current_pgrp_orphaned()) {
374 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
375 set_thread_flag(TIF_SIGPENDING
);
380 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
384 EXPORT_SYMBOL(tty_check_change
);
386 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
387 size_t count
, loff_t
*ppos
)
392 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
393 size_t count
, loff_t
*ppos
)
398 /* No kernel lock held - none needed ;) */
399 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
401 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
404 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
407 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
410 static long hung_up_tty_compat_ioctl(struct file
*file
,
411 unsigned int cmd
, unsigned long arg
)
413 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
416 static const struct file_operations tty_fops
= {
421 .unlocked_ioctl
= tty_ioctl
,
422 .compat_ioctl
= tty_compat_ioctl
,
424 .release
= tty_release
,
425 .fasync
= tty_fasync
,
428 #ifdef CONFIG_UNIX98_PTYS
429 static const struct file_operations ptmx_fops
= {
434 .unlocked_ioctl
= tty_ioctl
,
435 .compat_ioctl
= tty_compat_ioctl
,
437 .release
= tty_release
,
438 .fasync
= tty_fasync
,
442 static const struct file_operations console_fops
= {
445 .write
= redirected_tty_write
,
447 .unlocked_ioctl
= tty_ioctl
,
448 .compat_ioctl
= tty_compat_ioctl
,
450 .release
= tty_release
,
451 .fasync
= tty_fasync
,
454 static const struct file_operations hung_up_tty_fops
= {
456 .read
= hung_up_tty_read
,
457 .write
= hung_up_tty_write
,
458 .poll
= hung_up_tty_poll
,
459 .unlocked_ioctl
= hung_up_tty_ioctl
,
460 .compat_ioctl
= hung_up_tty_compat_ioctl
,
461 .release
= tty_release
,
464 static DEFINE_SPINLOCK(redirect_lock
);
465 static struct file
*redirect
;
468 * tty_wakeup - request more data
471 * Internal and external helper for wakeups of tty. This function
472 * informs the line discipline if present that the driver is ready
473 * to receive more output data.
476 void tty_wakeup(struct tty_struct
*tty
)
478 struct tty_ldisc
*ld
;
480 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
481 ld
= tty_ldisc_ref(tty
);
483 if (ld
->ops
->write_wakeup
)
484 ld
->ops
->write_wakeup(tty
);
488 wake_up_interruptible(&tty
->write_wait
);
491 EXPORT_SYMBOL_GPL(tty_wakeup
);
494 * tty_ldisc_flush - flush line discipline queue
497 * Flush the line discipline queue (if any) for this tty. If there
498 * is no line discipline active this is a no-op.
501 void tty_ldisc_flush(struct tty_struct
*tty
)
503 struct tty_ldisc
*ld
= tty_ldisc_ref(tty
);
505 if (ld
->ops
->flush_buffer
)
506 ld
->ops
->flush_buffer(tty
);
509 tty_buffer_flush(tty
);
512 EXPORT_SYMBOL_GPL(tty_ldisc_flush
);
515 * tty_reset_termios - reset terminal state
518 * Restore a terminal to the driver default state
521 static void tty_reset_termios(struct tty_struct
*tty
)
523 mutex_lock(&tty
->termios_mutex
);
524 *tty
->termios
= tty
->driver
->init_termios
;
525 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
526 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
527 mutex_unlock(&tty
->termios_mutex
);
531 * do_tty_hangup - actual handler for hangup events
534 * This can be called by the "eventd" kernel thread. That is process
535 * synchronous but doesn't hold any locks, so we need to make sure we
536 * have the appropriate locks for what we're doing.
538 * The hangup event clears any pending redirections onto the hung up
539 * device. It ensures future writes will error and it does the needed
540 * line discipline hangup and signal delivery. The tty object itself
545 * redirect lock for undoing redirection
546 * file list lock for manipulating list of ttys
547 * tty_ldisc_lock from called functions
548 * termios_mutex resetting termios data
549 * tasklist_lock to walk task list for hangup event
550 * ->siglock to protect ->signal/->sighand
552 static void do_tty_hangup(struct work_struct
*work
)
554 struct tty_struct
*tty
=
555 container_of(work
, struct tty_struct
, hangup_work
);
556 struct file
*cons_filp
= NULL
;
557 struct file
*filp
, *f
= NULL
;
558 struct task_struct
*p
;
559 struct tty_ldisc
*ld
;
560 int closecount
= 0, n
;
567 /* inuse_filps is protected by the single kernel lock */
570 spin_lock(&redirect_lock
);
571 if (redirect
&& redirect
->private_data
== tty
) {
575 spin_unlock(&redirect_lock
);
577 check_tty_count(tty
, "do_tty_hangup");
579 /* This breaks for file handles being sent over AF_UNIX sockets ? */
580 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
581 if (filp
->f_op
->write
== redirected_tty_write
)
583 if (filp
->f_op
->write
!= tty_write
)
586 tty_fasync(-1, filp
, 0); /* can't block */
587 filp
->f_op
= &hung_up_tty_fops
;
591 * FIXME! What are the locking issues here? This may me overdoing
592 * things... This question is especially important now that we've
593 * removed the irqlock.
595 ld
= tty_ldisc_ref(tty
);
597 /* We may have no line discipline at this point */
598 if (ld
->ops
->flush_buffer
)
599 ld
->ops
->flush_buffer(tty
);
600 tty_driver_flush_buffer(tty
);
601 if ((test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) &&
602 ld
->ops
->write_wakeup
)
603 ld
->ops
->write_wakeup(tty
);
605 ld
->ops
->hangup(tty
);
608 * FIXME: Once we trust the LDISC code better we can wait here for
609 * ldisc completion and fix the driver call race
611 wake_up_interruptible(&tty
->write_wait
);
612 wake_up_interruptible(&tty
->read_wait
);
614 * Shutdown the current line discipline, and reset it to
617 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
618 tty_reset_termios(tty
);
619 /* Defer ldisc switch */
620 /* tty_deferred_ldisc_switch(N_TTY);
622 This should get done automatically when the port closes and
623 tty_release is called */
625 read_lock(&tasklist_lock
);
627 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
628 spin_lock_irq(&p
->sighand
->siglock
);
629 if (p
->signal
->tty
== tty
) {
630 p
->signal
->tty
= NULL
;
631 /* We defer the dereferences outside fo
635 if (!p
->signal
->leader
) {
636 spin_unlock_irq(&p
->sighand
->siglock
);
639 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
640 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
641 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
642 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
644 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
645 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
646 spin_unlock_irq(&p
->sighand
->siglock
);
647 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
649 read_unlock(&tasklist_lock
);
651 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
653 put_pid(tty
->session
);
657 tty
->ctrl_status
= 0;
658 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
660 /* Account for the p->signal references we killed */
665 * If one of the devices matches a console pointer, we
666 * cannot just call hangup() because that will cause
667 * tty->count and state->count to go out of sync.
668 * So we just call close() the right number of times.
672 for (n
= 0; n
< closecount
; n
++)
673 tty
->ops
->close(tty
, cons_filp
);
674 } else if (tty
->ops
->hangup
)
675 (tty
->ops
->hangup
)(tty
);
677 * We don't want to have driver/ldisc interactions beyond
678 * the ones we did here. The driver layer expects no
679 * calls after ->hangup() from the ldisc side. However we
680 * can't yet guarantee all that.
682 set_bit(TTY_HUPPED
, &tty
->flags
);
684 tty_ldisc_enable(tty
);
693 * tty_hangup - trigger a hangup event
694 * @tty: tty to hangup
696 * A carrier loss (virtual or otherwise) has occurred on this like
697 * schedule a hangup sequence to run after this event.
700 void tty_hangup(struct tty_struct
*tty
)
702 #ifdef TTY_DEBUG_HANGUP
704 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
706 schedule_work(&tty
->hangup_work
);
709 EXPORT_SYMBOL(tty_hangup
);
712 * tty_vhangup - process vhangup
713 * @tty: tty to hangup
715 * The user has asked via system call for the terminal to be hung up.
716 * We do this synchronously so that when the syscall returns the process
717 * is complete. That guarantee is necessary for security reasons.
720 void tty_vhangup(struct tty_struct
*tty
)
722 #ifdef TTY_DEBUG_HANGUP
725 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
727 do_tty_hangup(&tty
->hangup_work
);
730 EXPORT_SYMBOL(tty_vhangup
);
733 * tty_hung_up_p - was tty hung up
734 * @filp: file pointer of tty
736 * Return true if the tty has been subject to a vhangup or a carrier
740 int tty_hung_up_p(struct file
*filp
)
742 return (filp
->f_op
== &hung_up_tty_fops
);
745 EXPORT_SYMBOL(tty_hung_up_p
);
747 static void session_clear_tty(struct pid
*session
)
749 struct task_struct
*p
;
750 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
752 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
756 * disassociate_ctty - disconnect controlling tty
757 * @on_exit: true if exiting so need to "hang up" the session
759 * This function is typically called only by the session leader, when
760 * it wants to disassociate itself from its controlling tty.
762 * It performs the following functions:
763 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
764 * (2) Clears the tty from being controlling the session
765 * (3) Clears the controlling tty for all processes in the
768 * The argument on_exit is set to 1 if called when a process is
769 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
772 * BKL is taken for hysterical raisins
773 * tty_mutex is taken to protect tty
774 * ->siglock is taken to protect ->signal/->sighand
775 * tasklist_lock is taken to walk process list for sessions
776 * ->siglock is taken to protect ->signal/->sighand
779 void disassociate_ctty(int on_exit
)
781 struct tty_struct
*tty
;
782 struct pid
*tty_pgrp
= NULL
;
785 mutex_lock(&tty_mutex
);
786 tty
= get_current_tty();
788 tty_pgrp
= get_pid(tty
->pgrp
);
789 mutex_unlock(&tty_mutex
);
791 if (on_exit
&& tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
795 } else if (on_exit
) {
796 struct pid
*old_pgrp
;
797 spin_lock_irq(¤t
->sighand
->siglock
);
798 old_pgrp
= current
->signal
->tty_old_pgrp
;
799 current
->signal
->tty_old_pgrp
= NULL
;
800 spin_unlock_irq(¤t
->sighand
->siglock
);
802 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
803 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
806 mutex_unlock(&tty_mutex
);
810 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
812 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
816 spin_lock_irq(¤t
->sighand
->siglock
);
817 put_pid(current
->signal
->tty_old_pgrp
);
818 current
->signal
->tty_old_pgrp
= NULL
;
819 spin_unlock_irq(¤t
->sighand
->siglock
);
821 mutex_lock(&tty_mutex
);
822 tty
= get_current_tty();
825 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
826 put_pid(tty
->session
);
830 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
833 #ifdef TTY_DEBUG_HANGUP
834 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
838 mutex_unlock(&tty_mutex
);
840 /* Now clear signal->tty under the lock */
841 read_lock(&tasklist_lock
);
842 session_clear_tty(task_session(current
));
843 read_unlock(&tasklist_lock
);
848 * no_tty - Ensure the current process does not have a controlling tty
852 struct task_struct
*tsk
= current
;
854 if (tsk
->signal
->leader
)
855 disassociate_ctty(0);
862 * stop_tty - propagate flow control
865 * Perform flow control to the driver. For PTY/TTY pairs we
866 * must also propagate the TIOCKPKT status. May be called
867 * on an already stopped device and will not re-call the driver
870 * This functionality is used by both the line disciplines for
871 * halting incoming flow and by the driver. It may therefore be
872 * called from any context, may be under the tty atomic_write_lock
876 * Uses the tty control lock internally
879 void stop_tty(struct tty_struct
*tty
)
882 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
884 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
888 if (tty
->link
&& tty
->link
->packet
) {
889 tty
->ctrl_status
&= ~TIOCPKT_START
;
890 tty
->ctrl_status
|= TIOCPKT_STOP
;
891 wake_up_interruptible(&tty
->link
->read_wait
);
893 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
895 (tty
->ops
->stop
)(tty
);
898 EXPORT_SYMBOL(stop_tty
);
901 * start_tty - propagate flow control
904 * Start a tty that has been stopped if at all possible. Perform
905 * any necessary wakeups and propagate the TIOCPKT status. If this
906 * is the tty was previous stopped and is being started then the
907 * driver start method is invoked and the line discipline woken.
913 void start_tty(struct tty_struct
*tty
)
916 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
917 if (!tty
->stopped
|| tty
->flow_stopped
) {
918 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
922 if (tty
->link
&& tty
->link
->packet
) {
923 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
924 tty
->ctrl_status
|= TIOCPKT_START
;
925 wake_up_interruptible(&tty
->link
->read_wait
);
927 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
929 (tty
->ops
->start
)(tty
);
930 /* If we have a running line discipline it may need kicking */
934 EXPORT_SYMBOL(start_tty
);
937 * tty_read - read method for tty device files
938 * @file: pointer to tty file
940 * @count: size of user buffer
943 * Perform the read system call function on this terminal device. Checks
944 * for hung up devices before calling the line discipline method.
947 * Locks the line discipline internally while needed. Multiple
948 * read calls may be outstanding in parallel.
951 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
955 struct tty_struct
*tty
;
957 struct tty_ldisc
*ld
;
959 tty
= (struct tty_struct
*)file
->private_data
;
960 inode
= file
->f_path
.dentry
->d_inode
;
961 if (tty_paranoia_check(tty
, inode
, "tty_read"))
963 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
966 /* We want to wait for the line discipline to sort out in this
968 ld
= tty_ldisc_ref_wait(tty
);
970 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
975 inode
->i_atime
= current_fs_time(inode
->i_sb
);
979 void tty_write_unlock(struct tty_struct
*tty
)
981 mutex_unlock(&tty
->atomic_write_lock
);
982 wake_up_interruptible(&tty
->write_wait
);
985 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
987 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
990 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
997 * Split writes up in sane blocksizes to avoid
998 * denial-of-service type attacks
1000 static inline ssize_t
do_tty_write(
1001 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1002 struct tty_struct
*tty
,
1004 const char __user
*buf
,
1007 ssize_t ret
, written
= 0;
1010 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
1015 * We chunk up writes into a temporary buffer. This
1016 * simplifies low-level drivers immensely, since they
1017 * don't have locking issues and user mode accesses.
1019 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1022 * The default chunk-size is 2kB, because the NTTY
1023 * layer has problems with bigger chunks. It will
1024 * claim to be able to handle more characters than
1027 * FIXME: This can probably go away now except that 64K chunks
1028 * are too likely to fail unless switched to vmalloc...
1031 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1036 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1037 if (tty
->write_cnt
< chunk
) {
1043 buf
= kmalloc(chunk
, GFP_KERNEL
);
1048 kfree(tty
->write_buf
);
1049 tty
->write_cnt
= chunk
;
1050 tty
->write_buf
= buf
;
1053 /* Do the write .. */
1055 size_t size
= count
;
1059 if (copy_from_user(tty
->write_buf
, buf
, size
))
1061 ret
= write(tty
, file
, tty
->write_buf
, size
);
1070 if (signal_pending(current
))
1075 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1076 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1080 tty_write_unlock(tty
);
1086 * tty_write - write method for tty device file
1087 * @file: tty file pointer
1088 * @buf: user data to write
1089 * @count: bytes to write
1092 * Write data to a tty device via the line discipline.
1095 * Locks the line discipline as required
1096 * Writes to the tty driver are serialized by the atomic_write_lock
1097 * and are then processed in chunks to the device. The line discipline
1098 * write method will not be involked in parallel for each device
1099 * The line discipline write method is called under the big
1100 * kernel lock for historical reasons. New code should not rely on this.
1103 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1104 size_t count
, loff_t
*ppos
)
1106 struct tty_struct
*tty
;
1107 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1109 struct tty_ldisc
*ld
;
1111 tty
= (struct tty_struct
*)file
->private_data
;
1112 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1114 if (!tty
|| !tty
->ops
->write
||
1115 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1117 /* Short term debug to catch buggy drivers */
1118 if (tty
->ops
->write_room
== NULL
)
1119 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1121 ld
= tty_ldisc_ref_wait(tty
);
1122 if (!ld
->ops
->write
)
1125 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1126 tty_ldisc_deref(ld
);
1130 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1131 size_t count
, loff_t
*ppos
)
1133 struct file
*p
= NULL
;
1135 spin_lock(&redirect_lock
);
1140 spin_unlock(&redirect_lock
);
1144 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1148 return tty_write(file
, buf
, count
, ppos
);
1151 static char ptychar
[] = "pqrstuvwxyzabcde";
1154 * pty_line_name - generate name for a pty
1155 * @driver: the tty driver in use
1156 * @index: the minor number
1157 * @p: output buffer of at least 6 bytes
1159 * Generate a name from a driver reference and write it to the output
1164 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1166 int i
= index
+ driver
->name_base
;
1167 /* ->name is initialized to "ttyp", but "tty" is expected */
1168 sprintf(p
, "%s%c%x",
1169 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1170 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1174 * pty_line_name - generate name for a tty
1175 * @driver: the tty driver in use
1176 * @index: the minor number
1177 * @p: output buffer of at least 7 bytes
1179 * Generate a name from a driver reference and write it to the output
1184 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1186 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1190 * init_dev - initialise a tty device
1191 * @driver: tty driver we are opening a device on
1192 * @idx: device index
1193 * @tty: returned tty structure
1195 * Prepare a tty device. This may not be a "new" clean device but
1196 * could also be an active device. The pty drivers require special
1197 * handling because of this.
1200 * The function is called under the tty_mutex, which
1201 * protects us from the tty struct or driver itself going away.
1203 * On exit the tty device has the line discipline attached and
1204 * a reference count of 1. If a pair was created for pty/tty use
1205 * and the other was a pty master then it too has a reference count of 1.
1207 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1208 * failed open. The new code protects the open with a mutex, so it's
1209 * really quite straightforward. The mutex locking can probably be
1210 * relaxed for the (most common) case of reopening a tty.
1213 static int init_dev(struct tty_driver
*driver
, int idx
,
1214 struct tty_struct
**ret_tty
)
1216 struct tty_struct
*tty
, *o_tty
;
1217 struct ktermios
*tp
, **tp_loc
, *o_tp
, **o_tp_loc
;
1218 struct ktermios
*ltp
, **ltp_loc
, *o_ltp
, **o_ltp_loc
;
1221 /* check whether we're reopening an existing tty */
1222 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1223 tty
= devpts_get_tty(idx
);
1225 * If we don't have a tty here on a slave open, it's because
1226 * the master already started the close process and there's
1227 * no relation between devpts file and tty anymore.
1229 if (!tty
&& driver
->subtype
== PTY_TYPE_SLAVE
) {
1234 * It's safe from now on because init_dev() is called with
1235 * tty_mutex held and release_dev() won't change tty->count
1236 * or tty->flags without having to grab tty_mutex
1238 if (tty
&& driver
->subtype
== PTY_TYPE_MASTER
)
1241 tty
= driver
->ttys
[idx
];
1243 if (tty
) goto fast_track
;
1246 * First time open is complex, especially for PTY devices.
1247 * This code guarantees that either everything succeeds and the
1248 * TTY is ready for operation, or else the table slots are vacated
1249 * and the allocated memory released. (Except that the termios
1250 * and locked termios may be retained.)
1253 if (!try_module_get(driver
->owner
)) {
1262 tty
= alloc_tty_struct();
1265 initialize_tty_struct(tty
);
1266 tty
->driver
= driver
;
1267 tty
->ops
= driver
->ops
;
1269 tty_line_name(driver
, idx
, tty
->name
);
1271 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1272 tp_loc
= &tty
->termios
;
1273 ltp_loc
= &tty
->termios_locked
;
1275 tp_loc
= &driver
->termios
[idx
];
1276 ltp_loc
= &driver
->termios_locked
[idx
];
1280 tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1283 *tp
= driver
->init_termios
;
1287 ltp
= kzalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1292 if (driver
->type
== TTY_DRIVER_TYPE_PTY
) {
1293 o_tty
= alloc_tty_struct();
1296 if (!try_module_get(driver
->other
->owner
)) {
1297 /* This cannot in fact currently happen */
1298 free_tty_struct(o_tty
);
1302 initialize_tty_struct(o_tty
);
1303 o_tty
->driver
= driver
->other
;
1304 o_tty
->ops
= driver
->ops
;
1306 tty_line_name(driver
->other
, idx
, o_tty
->name
);
1308 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1309 o_tp_loc
= &o_tty
->termios
;
1310 o_ltp_loc
= &o_tty
->termios_locked
;
1312 o_tp_loc
= &driver
->other
->termios
[idx
];
1313 o_ltp_loc
= &driver
->other
->termios_locked
[idx
];
1317 o_tp
= kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1320 *o_tp
= driver
->other
->init_termios
;
1324 o_ltp
= kzalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1330 * Everything allocated ... set up the o_tty structure.
1332 if (!(driver
->other
->flags
& TTY_DRIVER_DEVPTS_MEM
))
1333 driver
->other
->ttys
[idx
] = o_tty
;
1338 o_tty
->termios
= *o_tp_loc
;
1339 o_tty
->termios_locked
= *o_ltp_loc
;
1340 driver
->other
->refcount
++;
1341 if (driver
->subtype
== PTY_TYPE_MASTER
)
1344 /* Establish the links in both directions */
1350 * All structures have been allocated, so now we install them.
1351 * Failures after this point use release_tty to clean up, so
1352 * there's no need to null out the local pointers.
1354 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
))
1355 driver
->ttys
[idx
] = tty
;
1361 tty
->termios
= *tp_loc
;
1362 tty
->termios_locked
= *ltp_loc
;
1363 /* Compatibility until drivers always set this */
1364 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1365 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1370 * Structures all installed ... call the ldisc open routines.
1371 * If we fail here just call release_tty to clean up. No need
1372 * to decrement the use counts, as release_tty doesn't care.
1375 retval
= tty_ldisc_setup(tty
, o_tty
);
1378 goto release_mem_out
;
1382 * This fast open can be used if the tty is already open.
1383 * No memory is allocated, and the only failures are from
1384 * attempting to open a closing tty or attempting multiple
1385 * opens on a pty master.
1388 if (test_bit(TTY_CLOSING
, &tty
->flags
)) {
1392 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1393 driver
->subtype
== PTY_TYPE_MASTER
) {
1395 * special case for PTY masters: only one open permitted,
1396 * and the slave side open count is incremented as well.
1405 tty
->driver
= driver
; /* N.B. why do this every time?? */
1408 if (!test_bit(TTY_LDISC
, &tty
->flags
))
1409 printk(KERN_ERR
"init_dev but no ldisc\n");
1413 /* All paths come through here to release the mutex */
1417 /* Release locally allocated memory ... nothing placed in slots */
1421 module_put(o_tty
->driver
->owner
);
1422 free_tty_struct(o_tty
);
1426 free_tty_struct(tty
);
1429 module_put(driver
->owner
);
1433 /* call the tty release_tty routine to clean out this slot */
1435 if (printk_ratelimit())
1436 printk(KERN_INFO
"init_dev: ldisc open failed, "
1437 "clearing slot %d\n", idx
);
1438 release_tty(tty
, idx
);
1443 * release_one_tty - release tty structure memory
1444 * @kref: kref of tty we are obliterating
1446 * Releases memory associated with a tty structure, and clears out the
1447 * driver table slots. This function is called when a device is no longer
1448 * in use. It also gets called when setup of a device fails.
1451 * tty_mutex - sometimes only
1452 * takes the file list lock internally when working on the list
1453 * of ttys that the driver keeps.
1455 static void release_one_tty(struct kref
*kref
)
1457 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1458 struct tty_driver
*driver
= tty
->driver
;
1459 int devpts
= tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
;
1460 struct ktermios
*tp
;
1461 int idx
= tty
->index
;
1464 tty
->driver
->ttys
[idx
] = NULL
;
1466 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
1467 /* FIXME: Locking on ->termios array */
1470 tty
->driver
->termios
[idx
] = NULL
;
1473 tp
= tty
->termios_locked
;
1475 tty
->driver
->termios_locked
[idx
] = NULL
;
1481 /* FIXME: locking on tty->driver->refcount */
1482 tty
->driver
->refcount
--;
1483 module_put(driver
->owner
);
1486 list_del_init(&tty
->tty_files
);
1489 free_tty_struct(tty
);
1493 * tty_kref_put - release a tty kref
1496 * Release a reference to a tty device and if need be let the kref
1497 * layer destruct the object for us
1500 void tty_kref_put(struct tty_struct
*tty
)
1503 kref_put(&tty
->kref
, release_one_tty
);
1505 EXPORT_SYMBOL(tty_kref_put
);
1508 * release_tty - release tty structure memory
1510 * Release both @tty and a possible linked partner (think pty pair),
1511 * and decrement the refcount of the backing module.
1514 * tty_mutex - sometimes only
1515 * takes the file list lock internally when working on the list
1516 * of ttys that the driver keeps.
1517 * FIXME: should we require tty_mutex is held here ??
1520 static void release_tty(struct tty_struct
*tty
, int idx
)
1522 /* This should always be true but check for the moment */
1523 WARN_ON(tty
->index
!= idx
);
1526 tty_kref_put(tty
->link
);
1531 * Even releasing the tty structures is a tricky business.. We have
1532 * to be very careful that the structures are all released at the
1533 * same time, as interrupts might otherwise get the wrong pointers.
1535 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1536 * lead to double frees or releasing memory still in use.
1538 static void release_dev(struct file
*filp
)
1540 struct tty_struct
*tty
, *o_tty
;
1541 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1546 tty
= (struct tty_struct
*)filp
->private_data
;
1547 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
,
1551 check_tty_count(tty
, "release_dev");
1553 tty_fasync(-1, filp
, 0);
1556 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1557 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1558 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
1561 #ifdef TTY_PARANOIA_CHECK
1562 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1563 printk(KERN_DEBUG
"release_dev: bad idx when trying to "
1564 "free (%s)\n", tty
->name
);
1567 if (!(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
1568 if (tty
!= tty
->driver
->ttys
[idx
]) {
1569 printk(KERN_DEBUG
"release_dev: driver.table[%d] not tty "
1570 "for (%s)\n", idx
, tty
->name
);
1573 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
1574 printk(KERN_DEBUG
"release_dev: driver.termios[%d] not termios "
1579 if (tty
->termios_locked
!= tty
->driver
->termios_locked
[idx
]) {
1580 printk(KERN_DEBUG
"release_dev: driver.termios_locked[%d] not "
1581 "termios_locked for (%s)\n",
1588 #ifdef TTY_DEBUG_HANGUP
1589 printk(KERN_DEBUG
"release_dev of %s (tty count=%d)...",
1590 tty_name(tty
, buf
), tty
->count
);
1593 #ifdef TTY_PARANOIA_CHECK
1594 if (tty
->driver
->other
&&
1595 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
1596 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1597 printk(KERN_DEBUG
"release_dev: other->table[%d] "
1598 "not o_tty for (%s)\n",
1602 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
1603 printk(KERN_DEBUG
"release_dev: other->termios[%d] "
1604 "not o_termios for (%s)\n",
1608 if (o_tty
->termios_locked
!=
1609 tty
->driver
->other
->termios_locked
[idx
]) {
1610 printk(KERN_DEBUG
"release_dev: other->termios_locked["
1611 "%d] not o_termios_locked for (%s)\n",
1615 if (o_tty
->link
!= tty
) {
1616 printk(KERN_DEBUG
"release_dev: bad pty pointers\n");
1621 if (tty
->ops
->close
)
1622 tty
->ops
->close(tty
, filp
);
1625 * Sanity check: if tty->count is going to zero, there shouldn't be
1626 * any waiters on tty->read_wait or tty->write_wait. We test the
1627 * wait queues and kick everyone out _before_ actually starting to
1628 * close. This ensures that we won't block while releasing the tty
1631 * The test for the o_tty closing is necessary, since the master and
1632 * slave sides may close in any order. If the slave side closes out
1633 * first, its count will be one, since the master side holds an open.
1634 * Thus this test wouldn't be triggered at the time the slave closes,
1637 * Note that it's possible for the tty to be opened again while we're
1638 * flushing out waiters. By recalculating the closing flags before
1639 * each iteration we avoid any problems.
1642 /* Guard against races with tty->count changes elsewhere and
1643 opens on /dev/tty */
1645 mutex_lock(&tty_mutex
);
1646 tty_closing
= tty
->count
<= 1;
1647 o_tty_closing
= o_tty
&&
1648 (o_tty
->count
<= (pty_master
? 1 : 0));
1652 if (waitqueue_active(&tty
->read_wait
)) {
1653 wake_up(&tty
->read_wait
);
1656 if (waitqueue_active(&tty
->write_wait
)) {
1657 wake_up(&tty
->write_wait
);
1661 if (o_tty_closing
) {
1662 if (waitqueue_active(&o_tty
->read_wait
)) {
1663 wake_up(&o_tty
->read_wait
);
1666 if (waitqueue_active(&o_tty
->write_wait
)) {
1667 wake_up(&o_tty
->write_wait
);
1674 printk(KERN_WARNING
"release_dev: %s: read/write wait queue "
1675 "active!\n", tty_name(tty
, buf
));
1676 mutex_unlock(&tty_mutex
);
1681 * The closing flags are now consistent with the open counts on
1682 * both sides, and we've completed the last operation that could
1683 * block, so it's safe to proceed with closing.
1686 if (--o_tty
->count
< 0) {
1687 printk(KERN_WARNING
"release_dev: bad pty slave count "
1689 o_tty
->count
, tty_name(o_tty
, buf
));
1693 if (--tty
->count
< 0) {
1694 printk(KERN_WARNING
"release_dev: bad tty->count (%d) for %s\n",
1695 tty
->count
, tty_name(tty
, buf
));
1700 * We've decremented tty->count, so we need to remove this file
1701 * descriptor off the tty->tty_files list; this serves two
1703 * - check_tty_count sees the correct number of file descriptors
1704 * associated with this tty.
1705 * - do_tty_hangup no longer sees this file descriptor as
1706 * something that needs to be handled for hangups.
1709 filp
->private_data
= NULL
;
1712 * Perform some housekeeping before deciding whether to return.
1714 * Set the TTY_CLOSING flag if this was the last open. In the
1715 * case of a pty we may have to wait around for the other side
1716 * to close, and TTY_CLOSING makes sure we can't be reopened.
1719 set_bit(TTY_CLOSING
, &tty
->flags
);
1721 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1724 * If _either_ side is closing, make sure there aren't any
1725 * processes that still think tty or o_tty is their controlling
1728 if (tty_closing
|| o_tty_closing
) {
1729 read_lock(&tasklist_lock
);
1730 session_clear_tty(tty
->session
);
1732 session_clear_tty(o_tty
->session
);
1733 read_unlock(&tasklist_lock
);
1736 mutex_unlock(&tty_mutex
);
1738 /* check whether both sides are closing ... */
1739 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
1742 #ifdef TTY_DEBUG_HANGUP
1743 printk(KERN_DEBUG
"freeing tty structure...");
1746 * Ask the line discipline code to release its structures
1748 tty_ldisc_release(tty
, o_tty
);
1750 * The release_tty function takes care of the details of clearing
1751 * the slots and preserving the termios structure.
1753 release_tty(tty
, idx
);
1755 /* Make this pty number available for reallocation */
1757 devpts_kill_index(idx
);
1761 * tty_open - open a tty device
1762 * @inode: inode of device file
1763 * @filp: file pointer to tty
1765 * tty_open and tty_release keep up the tty count that contains the
1766 * number of opens done on a tty. We cannot use the inode-count, as
1767 * different inodes might point to the same tty.
1769 * Open-counting is needed for pty masters, as well as for keeping
1770 * track of serial lines: DTR is dropped when the last close happens.
1771 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1773 * The termios state of a pty is reset on first open so that
1774 * settings don't persist across reuse.
1776 * Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
1777 * tty->count should protect the rest.
1778 * ->siglock protects ->signal/->sighand
1781 static int __tty_open(struct inode
*inode
, struct file
*filp
)
1783 struct tty_struct
*tty
;
1785 struct tty_driver
*driver
;
1787 dev_t device
= inode
->i_rdev
;
1788 unsigned short saved_flags
= filp
->f_flags
;
1790 nonseekable_open(inode
, filp
);
1793 noctty
= filp
->f_flags
& O_NOCTTY
;
1797 mutex_lock(&tty_mutex
);
1799 if (device
== MKDEV(TTYAUX_MAJOR
, 0)) {
1800 tty
= get_current_tty();
1802 mutex_unlock(&tty_mutex
);
1805 driver
= tty
->driver
;
1807 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1809 /* FIXME: Should we take a driver reference ? */
1814 if (device
== MKDEV(TTY_MAJOR
, 0)) {
1815 extern struct tty_driver
*console_driver
;
1816 driver
= console_driver
;
1822 if (device
== MKDEV(TTYAUX_MAJOR
, 1)) {
1823 driver
= console_device(&index
);
1825 /* Don't let /dev/console block */
1826 filp
->f_flags
|= O_NONBLOCK
;
1830 mutex_unlock(&tty_mutex
);
1834 driver
= get_tty_driver(device
, &index
);
1836 mutex_unlock(&tty_mutex
);
1840 retval
= init_dev(driver
, index
, &tty
);
1841 mutex_unlock(&tty_mutex
);
1845 filp
->private_data
= tty
;
1846 file_move(filp
, &tty
->tty_files
);
1847 check_tty_count(tty
, "tty_open");
1848 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1849 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1851 #ifdef TTY_DEBUG_HANGUP
1852 printk(KERN_DEBUG
"opening %s...", tty
->name
);
1856 retval
= tty
->ops
->open(tty
, filp
);
1860 filp
->f_flags
= saved_flags
;
1862 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1863 !capable(CAP_SYS_ADMIN
))
1867 #ifdef TTY_DEBUG_HANGUP
1868 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
1872 if (retval
!= -ERESTARTSYS
)
1874 if (signal_pending(current
))
1878 * Need to reset f_op in case a hangup happened.
1880 if (filp
->f_op
== &hung_up_tty_fops
)
1881 filp
->f_op
= &tty_fops
;
1885 mutex_lock(&tty_mutex
);
1886 spin_lock_irq(¤t
->sighand
->siglock
);
1888 current
->signal
->leader
&&
1889 !current
->signal
->tty
&&
1890 tty
->session
== NULL
)
1891 __proc_set_tty(current
, tty
);
1892 spin_unlock_irq(¤t
->sighand
->siglock
);
1893 mutex_unlock(&tty_mutex
);
1897 /* BKL pushdown: scary code avoidance wrapper */
1898 static int tty_open(struct inode
*inode
, struct file
*filp
)
1903 ret
= __tty_open(inode
, filp
);
1910 #ifdef CONFIG_UNIX98_PTYS
1912 * ptmx_open - open a unix 98 pty master
1913 * @inode: inode of device file
1914 * @filp: file pointer to tty
1916 * Allocate a unix98 pty master device from the ptmx driver.
1918 * Locking: tty_mutex protects theinit_dev work. tty->count should
1920 * allocated_ptys_lock handles the list of free pty numbers
1923 static int __ptmx_open(struct inode
*inode
, struct file
*filp
)
1925 struct tty_struct
*tty
;
1929 nonseekable_open(inode
, filp
);
1931 /* find a device that is not in use. */
1932 index
= devpts_new_index();
1936 mutex_lock(&tty_mutex
);
1937 retval
= init_dev(ptm_driver
, index
, &tty
);
1938 mutex_unlock(&tty_mutex
);
1943 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
1944 filp
->private_data
= tty
;
1945 file_move(filp
, &tty
->tty_files
);
1947 retval
= devpts_pty_new(tty
->link
);
1951 check_tty_count(tty
, "ptmx_open");
1952 retval
= ptm_driver
->ops
->open(tty
, filp
);
1959 devpts_kill_index(index
);
1963 static int ptmx_open(struct inode
*inode
, struct file
*filp
)
1968 ret
= __ptmx_open(inode
, filp
);
1975 * tty_release - vfs callback for close
1976 * @inode: inode of tty
1977 * @filp: file pointer for handle to tty
1979 * Called the last time each file handle is closed that references
1980 * this tty. There may however be several such references.
1983 * Takes bkl. See release_dev
1986 static int tty_release(struct inode
*inode
, struct file
*filp
)
1995 * tty_poll - check tty status
1996 * @filp: file being polled
1997 * @wait: poll wait structures to update
1999 * Call the line discipline polling method to obtain the poll
2000 * status of the device.
2002 * Locking: locks called line discipline but ldisc poll method
2003 * may be re-entered freely by other callers.
2006 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2008 struct tty_struct
*tty
;
2009 struct tty_ldisc
*ld
;
2012 tty
= (struct tty_struct
*)filp
->private_data
;
2013 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2016 ld
= tty_ldisc_ref_wait(tty
);
2018 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
2019 tty_ldisc_deref(ld
);
2023 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2025 struct tty_struct
*tty
;
2026 unsigned long flags
;
2030 tty
= (struct tty_struct
*)filp
->private_data
;
2031 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2034 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2041 if (!waitqueue_active(&tty
->read_wait
))
2042 tty
->minimum_to_wake
= 1;
2043 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2046 type
= PIDTYPE_PGID
;
2048 pid
= task_pid(current
);
2051 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2052 retval
= __f_setown(filp
, pid
, type
, 0);
2056 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2057 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2066 * tiocsti - fake input character
2067 * @tty: tty to fake input into
2068 * @p: pointer to character
2070 * Fake input to a tty device. Does the necessary locking and
2073 * FIXME: does not honour flow control ??
2076 * Called functions take tty_ldisc_lock
2077 * current->signal->tty check is safe without locks
2079 * FIXME: may race normal receive processing
2082 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2085 struct tty_ldisc
*ld
;
2087 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2089 if (get_user(ch
, p
))
2091 ld
= tty_ldisc_ref_wait(tty
);
2092 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2093 tty_ldisc_deref(ld
);
2098 * tiocgwinsz - implement window query ioctl
2100 * @arg: user buffer for result
2102 * Copies the kernel idea of the window size into the user buffer.
2104 * Locking: tty->termios_mutex is taken to ensure the winsize data
2108 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2112 mutex_lock(&tty
->termios_mutex
);
2113 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2114 mutex_unlock(&tty
->termios_mutex
);
2116 return err
? -EFAULT
: 0;
2120 * tty_do_resize - resize event
2121 * @tty: tty being resized
2122 * @real_tty: real tty (not the same as tty if using a pty/tty pair)
2123 * @rows: rows (character)
2124 * @cols: cols (character)
2126 * Update the termios variables and send the neccessary signals to
2127 * peform a terminal resize correctly
2130 int tty_do_resize(struct tty_struct
*tty
, struct tty_struct
*real_tty
,
2133 struct pid
*pgrp
, *rpgrp
;
2134 unsigned long flags
;
2136 /* For a PTY we need to lock the tty side */
2137 mutex_lock(&real_tty
->termios_mutex
);
2138 if (!memcmp(ws
, &real_tty
->winsize
, sizeof(*ws
)))
2140 /* Get the PID values and reference them so we can
2141 avoid holding the tty ctrl lock while sending signals */
2142 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2143 pgrp
= get_pid(tty
->pgrp
);
2144 rpgrp
= get_pid(real_tty
->pgrp
);
2145 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2148 kill_pgrp(pgrp
, SIGWINCH
, 1);
2149 if (rpgrp
!= pgrp
&& rpgrp
)
2150 kill_pgrp(rpgrp
, SIGWINCH
, 1);
2156 real_tty
->winsize
= *ws
;
2158 mutex_unlock(&real_tty
->termios_mutex
);
2163 * tiocswinsz - implement window size set ioctl
2165 * @arg: user buffer for result
2167 * Copies the user idea of the window size to the kernel. Traditionally
2168 * this is just advisory information but for the Linux console it
2169 * actually has driver level meaning and triggers a VC resize.
2172 * Driver dependant. The default do_resize method takes the
2173 * tty termios mutex and ctrl_lock. The console takes its own lock
2174 * then calls into the default method.
2177 static int tiocswinsz(struct tty_struct
*tty
, struct tty_struct
*real_tty
,
2178 struct winsize __user
*arg
)
2180 struct winsize tmp_ws
;
2181 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2184 if (tty
->ops
->resize
)
2185 return tty
->ops
->resize(tty
, real_tty
, &tmp_ws
);
2187 return tty_do_resize(tty
, real_tty
, &tmp_ws
);
2191 * tioccons - allow admin to move logical console
2192 * @file: the file to become console
2194 * Allow the adminstrator to move the redirected console device
2196 * Locking: uses redirect_lock to guard the redirect information
2199 static int tioccons(struct file
*file
)
2201 if (!capable(CAP_SYS_ADMIN
))
2203 if (file
->f_op
->write
== redirected_tty_write
) {
2205 spin_lock(&redirect_lock
);
2208 spin_unlock(&redirect_lock
);
2213 spin_lock(&redirect_lock
);
2215 spin_unlock(&redirect_lock
);
2220 spin_unlock(&redirect_lock
);
2225 * fionbio - non blocking ioctl
2226 * @file: file to set blocking value
2227 * @p: user parameter
2229 * Historical tty interfaces had a blocking control ioctl before
2230 * the generic functionality existed. This piece of history is preserved
2231 * in the expected tty API of posix OS's.
2233 * Locking: none, the open fle handle ensures it won't go away.
2236 static int fionbio(struct file
*file
, int __user
*p
)
2240 if (get_user(nonblock
, p
))
2243 /* file->f_flags is still BKL protected in the fs layer - vomit */
2246 file
->f_flags
|= O_NONBLOCK
;
2248 file
->f_flags
&= ~O_NONBLOCK
;
2254 * tiocsctty - set controlling tty
2255 * @tty: tty structure
2256 * @arg: user argument
2258 * This ioctl is used to manage job control. It permits a session
2259 * leader to set this tty as the controlling tty for the session.
2262 * Takes tty_mutex() to protect tty instance
2263 * Takes tasklist_lock internally to walk sessions
2264 * Takes ->siglock() when updating signal->tty
2267 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2270 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2273 mutex_lock(&tty_mutex
);
2275 * The process must be a session leader and
2276 * not have a controlling tty already.
2278 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2285 * This tty is already the controlling
2286 * tty for another session group!
2288 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2292 read_lock(&tasklist_lock
);
2293 session_clear_tty(tty
->session
);
2294 read_unlock(&tasklist_lock
);
2300 proc_set_tty(current
, tty
);
2302 mutex_unlock(&tty_mutex
);
2307 * tty_get_pgrp - return a ref counted pgrp pid
2310 * Returns a refcounted instance of the pid struct for the process
2311 * group controlling the tty.
2314 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2316 unsigned long flags
;
2319 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2320 pgrp
= get_pid(tty
->pgrp
);
2321 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2325 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2328 * tiocgpgrp - get process group
2329 * @tty: tty passed by user
2330 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2333 * Obtain the process group of the tty. If there is no process group
2336 * Locking: none. Reference to current->signal->tty is safe.
2339 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2344 * (tty == real_tty) is a cheap way of
2345 * testing if the tty is NOT a master pty.
2347 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2349 pid
= tty_get_pgrp(real_tty
);
2350 ret
= put_user(pid_vnr(pid
), p
);
2356 * tiocspgrp - attempt to set process group
2357 * @tty: tty passed by user
2358 * @real_tty: tty side device matching tty passed by user
2361 * Set the process group of the tty to the session passed. Only
2362 * permitted where the tty session is our session.
2364 * Locking: RCU, ctrl lock
2367 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2371 int retval
= tty_check_change(real_tty
);
2372 unsigned long flags
;
2378 if (!current
->signal
->tty
||
2379 (current
->signal
->tty
!= real_tty
) ||
2380 (real_tty
->session
!= task_session(current
)))
2382 if (get_user(pgrp_nr
, p
))
2387 pgrp
= find_vpid(pgrp_nr
);
2392 if (session_of_pgrp(pgrp
) != task_session(current
))
2395 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2396 put_pid(real_tty
->pgrp
);
2397 real_tty
->pgrp
= get_pid(pgrp
);
2398 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2405 * tiocgsid - get session id
2406 * @tty: tty passed by user
2407 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2408 * @p: pointer to returned session id
2410 * Obtain the session id of the tty. If there is no session
2413 * Locking: none. Reference to current->signal->tty is safe.
2416 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2419 * (tty == real_tty) is a cheap way of
2420 * testing if the tty is NOT a master pty.
2422 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2424 if (!real_tty
->session
)
2426 return put_user(pid_vnr(real_tty
->session
), p
);
2430 * tiocsetd - set line discipline
2432 * @p: pointer to user data
2434 * Set the line discipline according to user request.
2436 * Locking: see tty_set_ldisc, this function is just a helper
2439 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2444 if (get_user(ldisc
, p
))
2448 ret
= tty_set_ldisc(tty
, ldisc
);
2455 * send_break - performed time break
2456 * @tty: device to break on
2457 * @duration: timeout in mS
2459 * Perform a timed break on hardware that lacks its own driver level
2460 * timed break functionality.
2463 * atomic_write_lock serializes
2467 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2471 if (tty
->ops
->break_ctl
== NULL
)
2474 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2475 retval
= tty
->ops
->break_ctl(tty
, duration
);
2477 /* Do the work ourselves */
2478 if (tty_write_lock(tty
, 0) < 0)
2480 retval
= tty
->ops
->break_ctl(tty
, -1);
2483 if (!signal_pending(current
))
2484 msleep_interruptible(duration
);
2485 retval
= tty
->ops
->break_ctl(tty
, 0);
2487 tty_write_unlock(tty
);
2488 if (signal_pending(current
))
2495 * tty_tiocmget - get modem status
2497 * @file: user file pointer
2498 * @p: pointer to result
2500 * Obtain the modem status bits from the tty driver if the feature
2501 * is supported. Return -EINVAL if it is not available.
2503 * Locking: none (up to the driver)
2506 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
2508 int retval
= -EINVAL
;
2510 if (tty
->ops
->tiocmget
) {
2511 retval
= tty
->ops
->tiocmget(tty
, file
);
2514 retval
= put_user(retval
, p
);
2520 * tty_tiocmset - set modem status
2522 * @file: user file pointer
2523 * @cmd: command - clear bits, set bits or set all
2524 * @p: pointer to desired bits
2526 * Set the modem status bits from the tty driver if the feature
2527 * is supported. Return -EINVAL if it is not available.
2529 * Locking: none (up to the driver)
2532 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
2536 unsigned int set
, clear
, val
;
2538 if (tty
->ops
->tiocmset
== NULL
)
2541 retval
= get_user(val
, p
);
2557 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2558 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2559 return tty
->ops
->tiocmset(tty
, file
, set
, clear
);
2563 * Split this up, as gcc can choke on it otherwise..
2565 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2567 struct tty_struct
*tty
, *real_tty
;
2568 void __user
*p
= (void __user
*)arg
;
2570 struct tty_ldisc
*ld
;
2571 struct inode
*inode
= file
->f_dentry
->d_inode
;
2573 tty
= (struct tty_struct
*)file
->private_data
;
2574 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2578 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2579 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2580 real_tty
= tty
->link
;
2584 * Factor out some common prep work
2592 retval
= tty_check_change(tty
);
2595 if (cmd
!= TIOCCBRK
) {
2596 tty_wait_until_sent(tty
, 0);
2597 if (signal_pending(current
))
2608 return tiocsti(tty
, p
);
2610 return tiocgwinsz(real_tty
, p
);
2612 return tiocswinsz(tty
, real_tty
, p
);
2614 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2616 return fionbio(file
, p
);
2618 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2621 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2624 if (current
->signal
->tty
!= tty
)
2629 return tiocsctty(tty
, arg
);
2631 return tiocgpgrp(tty
, real_tty
, p
);
2633 return tiocspgrp(tty
, real_tty
, p
);
2635 return tiocgsid(tty
, real_tty
, p
);
2637 return put_user(tty
->ldisc
.ops
->num
, (int __user
*)p
);
2639 return tiocsetd(tty
, p
);
2643 case TIOCSBRK
: /* Turn break on, unconditionally */
2644 if (tty
->ops
->break_ctl
)
2645 return tty
->ops
->break_ctl(tty
, -1);
2647 case TIOCCBRK
: /* Turn break off, unconditionally */
2648 if (tty
->ops
->break_ctl
)
2649 return tty
->ops
->break_ctl(tty
, 0);
2651 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2652 /* non-zero arg means wait for all output data
2653 * to be sent (performed above) but don't send break.
2654 * This is used by the tcdrain() termios function.
2657 return send_break(tty
, 250);
2659 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2660 return send_break(tty
, arg
? arg
*100 : 250);
2663 return tty_tiocmget(tty
, file
, p
);
2667 return tty_tiocmset(tty
, file
, cmd
, p
);
2672 /* flush tty buffer and allow ldisc to process ioctl */
2673 tty_buffer_flush(tty
);
2678 if (tty
->ops
->ioctl
) {
2679 retval
= (tty
->ops
->ioctl
)(tty
, file
, cmd
, arg
);
2680 if (retval
!= -ENOIOCTLCMD
)
2683 ld
= tty_ldisc_ref_wait(tty
);
2685 if (ld
->ops
->ioctl
) {
2686 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2687 if (retval
== -ENOIOCTLCMD
)
2690 tty_ldisc_deref(ld
);
2694 #ifdef CONFIG_COMPAT
2695 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2698 struct inode
*inode
= file
->f_dentry
->d_inode
;
2699 struct tty_struct
*tty
= file
->private_data
;
2700 struct tty_ldisc
*ld
;
2701 int retval
= -ENOIOCTLCMD
;
2703 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2706 if (tty
->ops
->compat_ioctl
) {
2707 retval
= (tty
->ops
->compat_ioctl
)(tty
, file
, cmd
, arg
);
2708 if (retval
!= -ENOIOCTLCMD
)
2712 ld
= tty_ldisc_ref_wait(tty
);
2713 if (ld
->ops
->compat_ioctl
)
2714 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2715 tty_ldisc_deref(ld
);
2722 * This implements the "Secure Attention Key" --- the idea is to
2723 * prevent trojan horses by killing all processes associated with this
2724 * tty when the user hits the "Secure Attention Key". Required for
2725 * super-paranoid applications --- see the Orange Book for more details.
2727 * This code could be nicer; ideally it should send a HUP, wait a few
2728 * seconds, then send a INT, and then a KILL signal. But you then
2729 * have to coordinate with the init process, since all processes associated
2730 * with the current tty must be dead before the new getty is allowed
2733 * Now, if it would be correct ;-/ The current code has a nasty hole -
2734 * it doesn't catch files in flight. We may send the descriptor to ourselves
2735 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2737 * Nasty bug: do_SAK is being called in interrupt context. This can
2738 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2740 void __do_SAK(struct tty_struct
*tty
)
2745 struct task_struct
*g
, *p
;
2746 struct pid
*session
;
2749 struct fdtable
*fdt
;
2753 session
= tty
->session
;
2755 tty_ldisc_flush(tty
);
2757 tty_driver_flush_buffer(tty
);
2759 read_lock(&tasklist_lock
);
2760 /* Kill the entire session */
2761 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2762 printk(KERN_NOTICE
"SAK: killed process %d"
2763 " (%s): task_session_nr(p)==tty->session\n",
2764 task_pid_nr(p
), p
->comm
);
2765 send_sig(SIGKILL
, p
, 1);
2766 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2767 /* Now kill any processes that happen to have the
2770 do_each_thread(g
, p
) {
2771 if (p
->signal
->tty
== tty
) {
2772 printk(KERN_NOTICE
"SAK: killed process %d"
2773 " (%s): task_session_nr(p)==tty->session\n",
2774 task_pid_nr(p
), p
->comm
);
2775 send_sig(SIGKILL
, p
, 1);
2781 * We don't take a ref to the file, so we must
2782 * hold ->file_lock instead.
2784 spin_lock(&p
->files
->file_lock
);
2785 fdt
= files_fdtable(p
->files
);
2786 for (i
= 0; i
< fdt
->max_fds
; i
++) {
2787 filp
= fcheck_files(p
->files
, i
);
2790 if (filp
->f_op
->read
== tty_read
&&
2791 filp
->private_data
== tty
) {
2792 printk(KERN_NOTICE
"SAK: killed process %d"
2793 " (%s): fd#%d opened to the tty\n",
2794 task_pid_nr(p
), p
->comm
, i
);
2795 force_sig(SIGKILL
, p
);
2799 spin_unlock(&p
->files
->file_lock
);
2802 } while_each_thread(g
, p
);
2803 read_unlock(&tasklist_lock
);
2807 static void do_SAK_work(struct work_struct
*work
)
2809 struct tty_struct
*tty
=
2810 container_of(work
, struct tty_struct
, SAK_work
);
2815 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2816 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2817 * the values which we write to it will be identical to the values which it
2818 * already has. --akpm
2820 void do_SAK(struct tty_struct
*tty
)
2824 schedule_work(&tty
->SAK_work
);
2827 EXPORT_SYMBOL(do_SAK
);
2830 * initialize_tty_struct
2831 * @tty: tty to initialize
2833 * This subroutine initializes a tty structure that has been newly
2836 * Locking: none - tty in question must not be exposed at this point
2839 static void initialize_tty_struct(struct tty_struct
*tty
)
2841 memset(tty
, 0, sizeof(struct tty_struct
));
2842 kref_init(&tty
->kref
);
2843 tty
->magic
= TTY_MAGIC
;
2844 tty_ldisc_init(tty
);
2845 tty
->session
= NULL
;
2847 tty
->overrun_time
= jiffies
;
2848 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
2849 tty_buffer_init(tty
);
2850 mutex_init(&tty
->termios_mutex
);
2851 init_waitqueue_head(&tty
->write_wait
);
2852 init_waitqueue_head(&tty
->read_wait
);
2853 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2854 mutex_init(&tty
->atomic_read_lock
);
2855 mutex_init(&tty
->atomic_write_lock
);
2856 spin_lock_init(&tty
->read_lock
);
2857 spin_lock_init(&tty
->ctrl_lock
);
2858 INIT_LIST_HEAD(&tty
->tty_files
);
2859 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2863 * tty_put_char - write one character to a tty
2867 * Write one byte to the tty using the provided put_char method
2868 * if present. Returns the number of characters successfully output.
2870 * Note: the specific put_char operation in the driver layer may go
2871 * away soon. Don't call it directly, use this method
2874 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2876 if (tty
->ops
->put_char
)
2877 return tty
->ops
->put_char(tty
, ch
);
2878 return tty
->ops
->write(tty
, &ch
, 1);
2881 EXPORT_SYMBOL_GPL(tty_put_char
);
2883 static struct class *tty_class
;
2886 * tty_register_device - register a tty device
2887 * @driver: the tty driver that describes the tty device
2888 * @index: the index in the tty driver for this tty device
2889 * @device: a struct device that is associated with this tty device.
2890 * This field is optional, if there is no known struct device
2891 * for this tty device it can be set to NULL safely.
2893 * Returns a pointer to the struct device for this tty device
2894 * (or ERR_PTR(-EFOO) on error).
2896 * This call is required to be made to register an individual tty device
2897 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2898 * that bit is not set, this function should not be called by a tty
2904 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2905 struct device
*device
)
2908 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2910 if (index
>= driver
->num
) {
2911 printk(KERN_ERR
"Attempt to register invalid tty line number "
2913 return ERR_PTR(-EINVAL
);
2916 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2917 pty_line_name(driver
, index
, name
);
2919 tty_line_name(driver
, index
, name
);
2921 return device_create_drvdata(tty_class
, device
, dev
, NULL
, name
);
2925 * tty_unregister_device - unregister a tty device
2926 * @driver: the tty driver that describes the tty device
2927 * @index: the index in the tty driver for this tty device
2929 * If a tty device is registered with a call to tty_register_device() then
2930 * this function must be called when the tty device is gone.
2935 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
2937 device_destroy(tty_class
,
2938 MKDEV(driver
->major
, driver
->minor_start
) + index
);
2941 EXPORT_SYMBOL(tty_register_device
);
2942 EXPORT_SYMBOL(tty_unregister_device
);
2944 struct tty_driver
*alloc_tty_driver(int lines
)
2946 struct tty_driver
*driver
;
2948 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
2950 driver
->magic
= TTY_DRIVER_MAGIC
;
2951 driver
->num
= lines
;
2952 /* later we'll move allocation of tables here */
2957 void put_tty_driver(struct tty_driver
*driver
)
2962 void tty_set_operations(struct tty_driver
*driver
,
2963 const struct tty_operations
*op
)
2968 EXPORT_SYMBOL(alloc_tty_driver
);
2969 EXPORT_SYMBOL(put_tty_driver
);
2970 EXPORT_SYMBOL(tty_set_operations
);
2973 * Called by a tty driver to register itself.
2975 int tty_register_driver(struct tty_driver
*driver
)
2982 if (driver
->flags
& TTY_DRIVER_INSTALLED
)
2985 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
2986 p
= kzalloc(driver
->num
* 3 * sizeof(void *), GFP_KERNEL
);
2991 if (!driver
->major
) {
2992 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
2993 driver
->num
, driver
->name
);
2995 driver
->major
= MAJOR(dev
);
2996 driver
->minor_start
= MINOR(dev
);
2999 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3000 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3008 driver
->ttys
= (struct tty_struct
**)p
;
3009 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
3010 driver
->termios_locked
= (struct ktermios
**)
3011 (p
+ driver
->num
* 2);
3013 driver
->ttys
= NULL
;
3014 driver
->termios
= NULL
;
3015 driver
->termios_locked
= NULL
;
3018 cdev_init(&driver
->cdev
, &tty_fops
);
3019 driver
->cdev
.owner
= driver
->owner
;
3020 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
3022 unregister_chrdev_region(dev
, driver
->num
);
3023 driver
->ttys
= NULL
;
3024 driver
->termios
= driver
->termios_locked
= NULL
;
3029 mutex_lock(&tty_mutex
);
3030 list_add(&driver
->tty_drivers
, &tty_drivers
);
3031 mutex_unlock(&tty_mutex
);
3033 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3034 for (i
= 0; i
< driver
->num
; i
++)
3035 tty_register_device(driver
, i
, NULL
);
3037 proc_tty_register_driver(driver
);
3041 EXPORT_SYMBOL(tty_register_driver
);
3044 * Called by a tty driver to unregister itself.
3046 int tty_unregister_driver(struct tty_driver
*driver
)
3049 struct ktermios
*tp
;
3052 if (driver
->refcount
)
3055 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3057 mutex_lock(&tty_mutex
);
3058 list_del(&driver
->tty_drivers
);
3059 mutex_unlock(&tty_mutex
);
3062 * Free the termios and termios_locked structures because
3063 * we don't want to get memory leaks when modular tty
3064 * drivers are removed from the kernel.
3066 for (i
= 0; i
< driver
->num
; i
++) {
3067 tp
= driver
->termios
[i
];
3069 driver
->termios
[i
] = NULL
;
3072 tp
= driver
->termios_locked
[i
];
3074 driver
->termios_locked
[i
] = NULL
;
3077 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3078 tty_unregister_device(driver
, i
);
3081 proc_tty_unregister_driver(driver
);
3082 driver
->ttys
= NULL
;
3083 driver
->termios
= driver
->termios_locked
= NULL
;
3085 cdev_del(&driver
->cdev
);
3088 EXPORT_SYMBOL(tty_unregister_driver
);
3090 dev_t
tty_devnum(struct tty_struct
*tty
)
3092 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3094 EXPORT_SYMBOL(tty_devnum
);
3096 void proc_clear_tty(struct task_struct
*p
)
3098 struct tty_struct
*tty
;
3099 spin_lock_irq(&p
->sighand
->siglock
);
3100 tty
= p
->signal
->tty
;
3101 p
->signal
->tty
= NULL
;
3102 spin_unlock_irq(&p
->sighand
->siglock
);
3106 /* Called under the sighand lock */
3108 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3111 unsigned long flags
;
3112 /* We should not have a session or pgrp to put here but.... */
3113 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3114 put_pid(tty
->session
);
3116 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3117 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3118 tty
->session
= get_pid(task_session(tsk
));
3119 if (tsk
->signal
->tty
) {
3120 printk(KERN_DEBUG
"tty not NULL!!\n");
3121 tty_kref_put(tsk
->signal
->tty
);
3124 put_pid(tsk
->signal
->tty_old_pgrp
);
3125 tsk
->signal
->tty
= tty_kref_get(tty
);
3126 tsk
->signal
->tty_old_pgrp
= NULL
;
3129 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3131 spin_lock_irq(&tsk
->sighand
->siglock
);
3132 __proc_set_tty(tsk
, tty
);
3133 spin_unlock_irq(&tsk
->sighand
->siglock
);
3136 struct tty_struct
*get_current_tty(void)
3138 struct tty_struct
*tty
;
3139 WARN_ON_ONCE(!mutex_is_locked(&tty_mutex
));
3140 tty
= tty_kref_get(current
->signal
->tty
);
3142 * session->tty can be changed/cleared from under us, make sure we
3143 * issue the load. The obtained pointer, when not NULL, is valid as
3144 * long as we hold tty_mutex.
3149 EXPORT_SYMBOL_GPL(get_current_tty
);
3152 * Initialize the console device. This is called *early*, so
3153 * we can't necessarily depend on lots of kernel help here.
3154 * Just do some early initializations, and do the complex setup
3157 void __init
console_init(void)
3161 /* Setup the default TTY line discipline. */
3165 * set up the console device so that later boot sequences can
3166 * inform about problems etc..
3168 call
= __con_initcall_start
;
3169 while (call
< __con_initcall_end
) {
3175 static int __init
tty_class_init(void)
3177 tty_class
= class_create(THIS_MODULE
, "tty");
3178 if (IS_ERR(tty_class
))
3179 return PTR_ERR(tty_class
);
3183 postcore_initcall(tty_class_init
);
3185 /* 3/2004 jmc: why do these devices exist? */
3187 static struct cdev tty_cdev
, console_cdev
;
3188 #ifdef CONFIG_UNIX98_PTYS
3189 static struct cdev ptmx_cdev
;
3192 static struct cdev vc0_cdev
;
3196 * Ok, now we can initialize the rest of the tty devices and can count
3197 * on memory allocations, interrupts etc..
3199 static int __init
tty_init(void)
3201 cdev_init(&tty_cdev
, &tty_fops
);
3202 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3203 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3204 panic("Couldn't register /dev/tty driver\n");
3205 device_create_drvdata(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
,
3208 cdev_init(&console_cdev
, &console_fops
);
3209 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3210 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3211 panic("Couldn't register /dev/console driver\n");
3212 device_create_drvdata(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3215 #ifdef CONFIG_UNIX98_PTYS
3216 cdev_init(&ptmx_cdev
, &ptmx_fops
);
3217 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
3218 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
3219 panic("Couldn't register /dev/ptmx driver\n");
3220 device_create_drvdata(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), NULL
, "ptmx");
3224 cdev_init(&vc0_cdev
, &console_fops
);
3225 if (cdev_add(&vc0_cdev
, MKDEV(TTY_MAJOR
, 0), 1) ||
3226 register_chrdev_region(MKDEV(TTY_MAJOR
, 0), 1, "/dev/vc/0") < 0)
3227 panic("Couldn't register /dev/tty0 driver\n");
3228 device_create_drvdata(tty_class
, NULL
, MKDEV(TTY_MAJOR
, 0), NULL
, "tty0");
3234 module_init(tty_init
);