2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
98 #include <linux/uaccess.h>
99 #include <asm/system.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
114 .c_iflag
= ICRNL
| IXON
,
115 .c_oflag
= OPOST
| ONLCR
,
116 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
117 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
118 ECHOCTL
| ECHOKE
| IEXTEN
,
124 EXPORT_SYMBOL(tty_std_termios
);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex
);
135 EXPORT_SYMBOL(tty_mutex
);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock
);
140 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
141 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
142 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
144 static unsigned int tty_poll(struct file
*, poll_table
*);
145 static int tty_open(struct inode
*, struct file
*);
146 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
148 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd
, struct file
*filp
, int on
);
154 static int tty_fasync(int fd
, struct file
*filp
, int on
);
155 static void release_tty(struct tty_struct
*tty
, int idx
);
156 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
157 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
160 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct
*alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct
*tty
)
185 put_device(tty
->dev
);
186 kfree(tty
->write_buf
);
187 tty_buffer_free_all(tty
);
191 static inline struct tty_struct
*file_tty(struct file
*file
)
193 return ((struct tty_file_private
*)file
->private_data
)->tty
;
196 int tty_alloc_file(struct file
*file
)
198 struct tty_file_private
*priv
;
200 priv
= kmalloc(sizeof(*priv
), GFP_KERNEL
);
204 file
->private_data
= priv
;
209 /* Associate a new file with the tty structure */
210 void tty_add_file(struct tty_struct
*tty
, struct file
*file
)
212 struct tty_file_private
*priv
= file
->private_data
;
217 spin_lock(&tty_files_lock
);
218 list_add(&priv
->list
, &tty
->tty_files
);
219 spin_unlock(&tty_files_lock
);
223 * tty_free_file - free file->private_data
225 * This shall be used only for fail path handling when tty_add_file was not
228 void tty_free_file(struct file
*file
)
230 struct tty_file_private
*priv
= file
->private_data
;
232 file
->private_data
= NULL
;
236 /* Delete file from its tty */
237 void tty_del_file(struct file
*file
)
239 struct tty_file_private
*priv
= file
->private_data
;
241 spin_lock(&tty_files_lock
);
242 list_del(&priv
->list
);
243 spin_unlock(&tty_files_lock
);
248 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
251 * tty_name - return tty naming
252 * @tty: tty structure
253 * @buf: buffer for output
255 * Convert a tty structure into a name. The name reflects the kernel
256 * naming policy and if udev is in use may not reflect user space
261 char *tty_name(struct tty_struct
*tty
, char *buf
)
263 if (!tty
) /* Hmm. NULL pointer. That's fun. */
264 strcpy(buf
, "NULL tty");
266 strcpy(buf
, tty
->name
);
270 EXPORT_SYMBOL(tty_name
);
272 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
275 #ifdef TTY_PARANOIA_CHECK
278 "null TTY for (%d:%d) in %s\n",
279 imajor(inode
), iminor(inode
), routine
);
282 if (tty
->magic
!= TTY_MAGIC
) {
284 "bad magic number for tty struct (%d:%d) in %s\n",
285 imajor(inode
), iminor(inode
), routine
);
292 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
294 #ifdef CHECK_TTY_COUNT
298 spin_lock(&tty_files_lock
);
299 list_for_each(p
, &tty
->tty_files
) {
302 spin_unlock(&tty_files_lock
);
303 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
304 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
305 tty
->link
&& tty
->link
->count
)
307 if (tty
->count
!= count
) {
308 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
309 "!= #fd's(%d) in %s\n",
310 tty
->name
, tty
->count
, count
, routine
);
318 * get_tty_driver - find device of a tty
319 * @dev_t: device identifier
320 * @index: returns the index of the tty
322 * This routine returns a tty driver structure, given a device number
323 * and also passes back the index number.
325 * Locking: caller must hold tty_mutex
328 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
330 struct tty_driver
*p
;
332 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
333 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
334 if (device
< base
|| device
>= base
+ p
->num
)
336 *index
= device
- base
;
337 return tty_driver_kref_get(p
);
342 #ifdef CONFIG_CONSOLE_POLL
345 * tty_find_polling_driver - find device of a polled tty
346 * @name: name string to match
347 * @line: pointer to resulting tty line nr
349 * This routine returns a tty driver structure, given a name
350 * and the condition that the tty driver is capable of polled
353 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
355 struct tty_driver
*p
, *res
= NULL
;
360 for (str
= name
; *str
; str
++)
361 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
367 tty_line
= simple_strtoul(str
, &str
, 10);
369 mutex_lock(&tty_mutex
);
370 /* Search through the tty devices to look for a match */
371 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
372 if (strncmp(name
, p
->name
, len
) != 0)
380 if (tty_line
>= 0 && tty_line
< p
->num
&& p
->ops
&&
381 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
382 res
= tty_driver_kref_get(p
);
387 mutex_unlock(&tty_mutex
);
391 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
395 * tty_check_change - check for POSIX terminal changes
398 * If we try to write to, or set the state of, a terminal and we're
399 * not in the foreground, send a SIGTTOU. If the signal is blocked or
400 * ignored, go ahead and perform the operation. (POSIX 7.2)
405 int tty_check_change(struct tty_struct
*tty
)
410 if (current
->signal
->tty
!= tty
)
413 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
416 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
419 if (task_pgrp(current
) == tty
->pgrp
)
421 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
422 if (is_ignored(SIGTTOU
))
424 if (is_current_pgrp_orphaned()) {
428 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
429 set_thread_flag(TIF_SIGPENDING
);
434 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
438 EXPORT_SYMBOL(tty_check_change
);
440 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
441 size_t count
, loff_t
*ppos
)
446 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
447 size_t count
, loff_t
*ppos
)
452 /* No kernel lock held - none needed ;) */
453 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
455 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
458 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
461 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
464 static long hung_up_tty_compat_ioctl(struct file
*file
,
465 unsigned int cmd
, unsigned long arg
)
467 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
470 static const struct file_operations tty_fops
= {
475 .unlocked_ioctl
= tty_ioctl
,
476 .compat_ioctl
= tty_compat_ioctl
,
478 .release
= tty_release
,
479 .fasync
= tty_fasync
,
482 static const struct file_operations console_fops
= {
485 .write
= redirected_tty_write
,
487 .unlocked_ioctl
= tty_ioctl
,
488 .compat_ioctl
= tty_compat_ioctl
,
490 .release
= tty_release
,
491 .fasync
= tty_fasync
,
494 static const struct file_operations hung_up_tty_fops
= {
496 .read
= hung_up_tty_read
,
497 .write
= hung_up_tty_write
,
498 .poll
= hung_up_tty_poll
,
499 .unlocked_ioctl
= hung_up_tty_ioctl
,
500 .compat_ioctl
= hung_up_tty_compat_ioctl
,
501 .release
= tty_release
,
504 static DEFINE_SPINLOCK(redirect_lock
);
505 static struct file
*redirect
;
508 * tty_wakeup - request more data
511 * Internal and external helper for wakeups of tty. This function
512 * informs the line discipline if present that the driver is ready
513 * to receive more output data.
516 void tty_wakeup(struct tty_struct
*tty
)
518 struct tty_ldisc
*ld
;
520 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
521 ld
= tty_ldisc_ref(tty
);
523 if (ld
->ops
->write_wakeup
)
524 ld
->ops
->write_wakeup(tty
);
528 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
531 EXPORT_SYMBOL_GPL(tty_wakeup
);
534 * __tty_hangup - actual handler for hangup events
537 * This can be called by the "eventd" kernel thread. That is process
538 * synchronous but doesn't hold any locks, so we need to make sure we
539 * have the appropriate locks for what we're doing.
541 * The hangup event clears any pending redirections onto the hung up
542 * device. It ensures future writes will error and it does the needed
543 * line discipline hangup and signal delivery. The tty object itself
548 * redirect lock for undoing redirection
549 * file list lock for manipulating list of ttys
550 * tty_ldisc_lock from called functions
551 * termios_mutex resetting termios data
552 * tasklist_lock to walk task list for hangup event
553 * ->siglock to protect ->signal/->sighand
555 void __tty_hangup(struct tty_struct
*tty
)
557 struct file
*cons_filp
= NULL
;
558 struct file
*filp
, *f
= NULL
;
559 struct task_struct
*p
;
560 struct tty_file_private
*priv
;
561 int closecount
= 0, n
;
569 spin_lock(&redirect_lock
);
570 if (redirect
&& file_tty(redirect
) == tty
) {
574 spin_unlock(&redirect_lock
);
578 /* some functions below drop BTM, so we need this bit */
579 set_bit(TTY_HUPPING
, &tty
->flags
);
581 /* inuse_filps is protected by the single tty lock,
582 this really needs to change if we want to flush the
583 workqueue with the lock held */
584 check_tty_count(tty
, "tty_hangup");
586 spin_lock(&tty_files_lock
);
587 /* This breaks for file handles being sent over AF_UNIX sockets ? */
588 list_for_each_entry(priv
, &tty
->tty_files
, list
) {
590 if (filp
->f_op
->write
== redirected_tty_write
)
592 if (filp
->f_op
->write
!= tty_write
)
595 __tty_fasync(-1, filp
, 0); /* can't block */
596 filp
->f_op
= &hung_up_tty_fops
;
598 spin_unlock(&tty_files_lock
);
601 * it drops BTM and thus races with reopen
602 * we protect the race by TTY_HUPPING
604 tty_ldisc_hangup(tty
);
606 read_lock(&tasklist_lock
);
608 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
609 spin_lock_irq(&p
->sighand
->siglock
);
610 if (p
->signal
->tty
== tty
) {
611 p
->signal
->tty
= NULL
;
612 /* We defer the dereferences outside fo
616 if (!p
->signal
->leader
) {
617 spin_unlock_irq(&p
->sighand
->siglock
);
620 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
621 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
622 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
623 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
625 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
626 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
627 spin_unlock_irq(&p
->sighand
->siglock
);
628 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
630 read_unlock(&tasklist_lock
);
632 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
633 clear_bit(TTY_THROTTLED
, &tty
->flags
);
634 clear_bit(TTY_PUSH
, &tty
->flags
);
635 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
636 put_pid(tty
->session
);
640 tty
->ctrl_status
= 0;
641 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
643 /* Account for the p->signal references we killed */
648 * If one of the devices matches a console pointer, we
649 * cannot just call hangup() because that will cause
650 * tty->count and state->count to go out of sync.
651 * So we just call close() the right number of times.
655 for (n
= 0; n
< closecount
; n
++)
656 tty
->ops
->close(tty
, cons_filp
);
657 } else if (tty
->ops
->hangup
)
658 (tty
->ops
->hangup
)(tty
);
660 * We don't want to have driver/ldisc interactions beyond
661 * the ones we did here. The driver layer expects no
662 * calls after ->hangup() from the ldisc side. However we
663 * can't yet guarantee all that.
665 set_bit(TTY_HUPPED
, &tty
->flags
);
666 clear_bit(TTY_HUPPING
, &tty
->flags
);
667 tty_ldisc_enable(tty
);
675 static void do_tty_hangup(struct work_struct
*work
)
677 struct tty_struct
*tty
=
678 container_of(work
, struct tty_struct
, hangup_work
);
684 * tty_hangup - trigger a hangup event
685 * @tty: tty to hangup
687 * A carrier loss (virtual or otherwise) has occurred on this like
688 * schedule a hangup sequence to run after this event.
691 void tty_hangup(struct tty_struct
*tty
)
693 #ifdef TTY_DEBUG_HANGUP
695 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
697 schedule_work(&tty
->hangup_work
);
700 EXPORT_SYMBOL(tty_hangup
);
703 * tty_vhangup - process vhangup
704 * @tty: tty to hangup
706 * The user has asked via system call for the terminal to be hung up.
707 * We do this synchronously so that when the syscall returns the process
708 * is complete. That guarantee is necessary for security reasons.
711 void tty_vhangup(struct tty_struct
*tty
)
713 #ifdef TTY_DEBUG_HANGUP
716 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
721 EXPORT_SYMBOL(tty_vhangup
);
725 * tty_vhangup_self - process vhangup for own ctty
727 * Perform a vhangup on the current controlling tty
730 void tty_vhangup_self(void)
732 struct tty_struct
*tty
;
734 tty
= get_current_tty();
742 * tty_hung_up_p - was tty hung up
743 * @filp: file pointer of tty
745 * Return true if the tty has been subject to a vhangup or a carrier
749 int tty_hung_up_p(struct file
*filp
)
751 return (filp
->f_op
== &hung_up_tty_fops
);
754 EXPORT_SYMBOL(tty_hung_up_p
);
756 static void session_clear_tty(struct pid
*session
)
758 struct task_struct
*p
;
759 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
761 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
765 * disassociate_ctty - disconnect controlling tty
766 * @on_exit: true if exiting so need to "hang up" the session
768 * This function is typically called only by the session leader, when
769 * it wants to disassociate itself from its controlling tty.
771 * It performs the following functions:
772 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
773 * (2) Clears the tty from being controlling the session
774 * (3) Clears the controlling tty for all processes in the
777 * The argument on_exit is set to 1 if called when a process is
778 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
781 * BTM is taken for hysterical raisins, and held when
782 * called from no_tty().
783 * tty_mutex is taken to protect tty
784 * ->siglock is taken to protect ->signal/->sighand
785 * tasklist_lock is taken to walk process list for sessions
786 * ->siglock is taken to protect ->signal/->sighand
789 void disassociate_ctty(int on_exit
)
791 struct tty_struct
*tty
;
792 struct pid
*tty_pgrp
= NULL
;
794 if (!current
->signal
->leader
)
797 tty
= get_current_tty();
799 tty_pgrp
= get_pid(tty
->pgrp
);
801 if (tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
805 } else if (on_exit
) {
806 struct pid
*old_pgrp
;
807 spin_lock_irq(¤t
->sighand
->siglock
);
808 old_pgrp
= current
->signal
->tty_old_pgrp
;
809 current
->signal
->tty_old_pgrp
= NULL
;
810 spin_unlock_irq(¤t
->sighand
->siglock
);
812 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
813 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
819 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
821 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
825 spin_lock_irq(¤t
->sighand
->siglock
);
826 put_pid(current
->signal
->tty_old_pgrp
);
827 current
->signal
->tty_old_pgrp
= NULL
;
828 spin_unlock_irq(¤t
->sighand
->siglock
);
830 tty
= get_current_tty();
833 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
834 put_pid(tty
->session
);
838 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
841 #ifdef TTY_DEBUG_HANGUP
842 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
847 /* Now clear signal->tty under the lock */
848 read_lock(&tasklist_lock
);
849 session_clear_tty(task_session(current
));
850 read_unlock(&tasklist_lock
);
855 * no_tty - Ensure the current process does not have a controlling tty
859 struct task_struct
*tsk
= current
;
861 disassociate_ctty(0);
868 * stop_tty - propagate flow control
871 * Perform flow control to the driver. For PTY/TTY pairs we
872 * must also propagate the TIOCKPKT status. May be called
873 * on an already stopped device and will not re-call the driver
876 * This functionality is used by both the line disciplines for
877 * halting incoming flow and by the driver. It may therefore be
878 * called from any context, may be under the tty atomic_write_lock
882 * Uses the tty control lock internally
885 void stop_tty(struct tty_struct
*tty
)
888 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
890 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
894 if (tty
->link
&& tty
->link
->packet
) {
895 tty
->ctrl_status
&= ~TIOCPKT_START
;
896 tty
->ctrl_status
|= TIOCPKT_STOP
;
897 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
899 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
901 (tty
->ops
->stop
)(tty
);
904 EXPORT_SYMBOL(stop_tty
);
907 * start_tty - propagate flow control
910 * Start a tty that has been stopped if at all possible. Perform
911 * any necessary wakeups and propagate the TIOCPKT status. If this
912 * is the tty was previous stopped and is being started then the
913 * driver start method is invoked and the line discipline woken.
919 void start_tty(struct tty_struct
*tty
)
922 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
923 if (!tty
->stopped
|| tty
->flow_stopped
) {
924 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
928 if (tty
->link
&& tty
->link
->packet
) {
929 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
930 tty
->ctrl_status
|= TIOCPKT_START
;
931 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
933 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
935 (tty
->ops
->start
)(tty
);
936 /* If we have a running line discipline it may need kicking */
940 EXPORT_SYMBOL(start_tty
);
943 * tty_read - read method for tty device files
944 * @file: pointer to tty file
946 * @count: size of user buffer
949 * Perform the read system call function on this terminal device. Checks
950 * for hung up devices before calling the line discipline method.
953 * Locks the line discipline internally while needed. Multiple
954 * read calls may be outstanding in parallel.
957 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
961 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
962 struct tty_struct
*tty
= file_tty(file
);
963 struct tty_ldisc
*ld
;
965 if (tty_paranoia_check(tty
, inode
, "tty_read"))
967 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
970 /* We want to wait for the line discipline to sort out in this
972 ld
= tty_ldisc_ref_wait(tty
);
974 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
979 inode
->i_atime
= current_fs_time(inode
->i_sb
);
983 void tty_write_unlock(struct tty_struct
*tty
)
984 __releases(&tty
->atomic_write_lock
)
986 mutex_unlock(&tty
->atomic_write_lock
);
987 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
990 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
991 __acquires(&tty
->atomic_write_lock
)
993 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
996 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
1003 * Split writes up in sane blocksizes to avoid
1004 * denial-of-service type attacks
1006 static inline ssize_t
do_tty_write(
1007 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1008 struct tty_struct
*tty
,
1010 const char __user
*buf
,
1013 ssize_t ret
, written
= 0;
1016 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
1021 * We chunk up writes into a temporary buffer. This
1022 * simplifies low-level drivers immensely, since they
1023 * don't have locking issues and user mode accesses.
1025 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1028 * The default chunk-size is 2kB, because the NTTY
1029 * layer has problems with bigger chunks. It will
1030 * claim to be able to handle more characters than
1033 * FIXME: This can probably go away now except that 64K chunks
1034 * are too likely to fail unless switched to vmalloc...
1037 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1042 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1043 if (tty
->write_cnt
< chunk
) {
1044 unsigned char *buf_chunk
;
1049 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
1054 kfree(tty
->write_buf
);
1055 tty
->write_cnt
= chunk
;
1056 tty
->write_buf
= buf_chunk
;
1059 /* Do the write .. */
1061 size_t size
= count
;
1065 if (copy_from_user(tty
->write_buf
, buf
, size
))
1067 ret
= write(tty
, file
, tty
->write_buf
, size
);
1076 if (signal_pending(current
))
1081 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1082 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1086 tty_write_unlock(tty
);
1091 * tty_write_message - write a message to a certain tty, not just the console.
1092 * @tty: the destination tty_struct
1093 * @msg: the message to write
1095 * This is used for messages that need to be redirected to a specific tty.
1096 * We don't put it into the syslog queue right now maybe in the future if
1099 * We must still hold the BTM and test the CLOSING flag for the moment.
1102 void tty_write_message(struct tty_struct
*tty
, char *msg
)
1105 mutex_lock(&tty
->atomic_write_lock
);
1107 if (tty
->ops
->write
&& !test_bit(TTY_CLOSING
, &tty
->flags
)) {
1109 tty
->ops
->write(tty
, msg
, strlen(msg
));
1112 tty_write_unlock(tty
);
1119 * tty_write - write method for tty device file
1120 * @file: tty file pointer
1121 * @buf: user data to write
1122 * @count: bytes to write
1125 * Write data to a tty device via the line discipline.
1128 * Locks the line discipline as required
1129 * Writes to the tty driver are serialized by the atomic_write_lock
1130 * and are then processed in chunks to the device. The line discipline
1131 * write method will not be invoked in parallel for each device.
1134 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1135 size_t count
, loff_t
*ppos
)
1137 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1138 struct tty_struct
*tty
= file_tty(file
);
1139 struct tty_ldisc
*ld
;
1142 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1144 if (!tty
|| !tty
->ops
->write
||
1145 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1147 /* Short term debug to catch buggy drivers */
1148 if (tty
->ops
->write_room
== NULL
)
1149 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1151 ld
= tty_ldisc_ref_wait(tty
);
1152 if (!ld
->ops
->write
)
1155 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1156 tty_ldisc_deref(ld
);
1160 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1161 size_t count
, loff_t
*ppos
)
1163 struct file
*p
= NULL
;
1165 spin_lock(&redirect_lock
);
1170 spin_unlock(&redirect_lock
);
1174 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1178 return tty_write(file
, buf
, count
, ppos
);
1181 static char ptychar
[] = "pqrstuvwxyzabcde";
1184 * pty_line_name - generate name for a pty
1185 * @driver: the tty driver in use
1186 * @index: the minor number
1187 * @p: output buffer of at least 6 bytes
1189 * Generate a name from a driver reference and write it to the output
1194 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1196 int i
= index
+ driver
->name_base
;
1197 /* ->name is initialized to "ttyp", but "tty" is expected */
1198 sprintf(p
, "%s%c%x",
1199 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1200 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1204 * tty_line_name - generate name for a tty
1205 * @driver: the tty driver in use
1206 * @index: the minor number
1207 * @p: output buffer of at least 7 bytes
1209 * Generate a name from a driver reference and write it to the output
1214 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1216 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1220 * tty_driver_lookup_tty() - find an existing tty, if any
1221 * @driver: the driver for the tty
1222 * @idx: the minor number
1224 * Return the tty, if found or ERR_PTR() otherwise.
1226 * Locking: tty_mutex must be held. If tty is found, the mutex must
1227 * be held until the 'fast-open' is also done. Will change once we
1228 * have refcounting in the driver and per driver locking
1230 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1231 struct inode
*inode
, int idx
)
1233 struct tty_struct
*tty
;
1235 if (driver
->ops
->lookup
)
1236 return driver
->ops
->lookup(driver
, inode
, idx
);
1238 tty
= driver
->ttys
[idx
];
1243 * tty_init_termios - helper for termios setup
1244 * @tty: the tty to set up
1246 * Initialise the termios structures for this tty. Thus runs under
1247 * the tty_mutex currently so we can be relaxed about ordering.
1250 int tty_init_termios(struct tty_struct
*tty
)
1252 struct ktermios
*tp
;
1253 int idx
= tty
->index
;
1255 tp
= tty
->driver
->termios
[idx
];
1257 tp
= kzalloc(sizeof(struct ktermios
[2]), GFP_KERNEL
);
1260 memcpy(tp
, &tty
->driver
->init_termios
,
1261 sizeof(struct ktermios
));
1262 tty
->driver
->termios
[idx
] = tp
;
1265 tty
->termios_locked
= tp
+ 1;
1267 /* Compatibility until drivers always set this */
1268 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1269 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1272 EXPORT_SYMBOL_GPL(tty_init_termios
);
1275 * tty_driver_install_tty() - install a tty entry in the driver
1276 * @driver: the driver for the tty
1279 * Install a tty object into the driver tables. The tty->index field
1280 * will be set by the time this is called. This method is responsible
1281 * for ensuring any need additional structures are allocated and
1284 * Locking: tty_mutex for now
1286 static int tty_driver_install_tty(struct tty_driver
*driver
,
1287 struct tty_struct
*tty
)
1289 int idx
= tty
->index
;
1292 if (driver
->ops
->install
) {
1293 ret
= driver
->ops
->install(driver
, tty
);
1297 if (tty_init_termios(tty
) == 0) {
1298 tty_driver_kref_get(driver
);
1300 driver
->ttys
[idx
] = tty
;
1307 * tty_driver_remove_tty() - remove a tty from the driver tables
1308 * @driver: the driver for the tty
1309 * @idx: the minor number
1311 * Remvoe a tty object from the driver tables. The tty->index field
1312 * will be set by the time this is called.
1314 * Locking: tty_mutex for now
1316 void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1318 if (driver
->ops
->remove
)
1319 driver
->ops
->remove(driver
, tty
);
1321 driver
->ttys
[tty
->index
] = NULL
;
1325 * tty_reopen() - fast re-open of an open tty
1326 * @tty - the tty to open
1328 * Return 0 on success, -errno on error.
1330 * Locking: tty_mutex must be held from the time the tty was found
1331 * till this open completes.
1333 static int tty_reopen(struct tty_struct
*tty
)
1335 struct tty_driver
*driver
= tty
->driver
;
1337 if (test_bit(TTY_CLOSING
, &tty
->flags
) ||
1338 test_bit(TTY_HUPPING
, &tty
->flags
) ||
1339 test_bit(TTY_LDISC_CHANGING
, &tty
->flags
))
1342 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1343 driver
->subtype
== PTY_TYPE_MASTER
) {
1345 * special case for PTY masters: only one open permitted,
1346 * and the slave side open count is incremented as well.
1354 tty
->driver
= driver
; /* N.B. why do this every time?? */
1356 mutex_lock(&tty
->ldisc_mutex
);
1357 WARN_ON(!test_bit(TTY_LDISC
, &tty
->flags
));
1358 mutex_unlock(&tty
->ldisc_mutex
);
1364 * tty_init_dev - initialise a tty device
1365 * @driver: tty driver we are opening a device on
1366 * @idx: device index
1367 * @ret_tty: returned tty structure
1368 * @first_ok: ok to open a new device (used by ptmx)
1370 * Prepare a tty device. This may not be a "new" clean device but
1371 * could also be an active device. The pty drivers require special
1372 * handling because of this.
1375 * The function is called under the tty_mutex, which
1376 * protects us from the tty struct or driver itself going away.
1378 * On exit the tty device has the line discipline attached and
1379 * a reference count of 1. If a pair was created for pty/tty use
1380 * and the other was a pty master then it too has a reference count of 1.
1382 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1383 * failed open. The new code protects the open with a mutex, so it's
1384 * really quite straightforward. The mutex locking can probably be
1385 * relaxed for the (most common) case of reopening a tty.
1388 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
,
1391 struct tty_struct
*tty
;
1394 /* Check if pty master is being opened multiple times */
1395 if (driver
->subtype
== PTY_TYPE_MASTER
&&
1396 (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && !first_ok
) {
1397 return ERR_PTR(-EIO
);
1401 * First time open is complex, especially for PTY devices.
1402 * This code guarantees that either everything succeeds and the
1403 * TTY is ready for operation, or else the table slots are vacated
1404 * and the allocated memory released. (Except that the termios
1405 * and locked termios may be retained.)
1408 if (!try_module_get(driver
->owner
))
1409 return ERR_PTR(-ENODEV
);
1411 tty
= alloc_tty_struct();
1414 goto err_module_put
;
1416 initialize_tty_struct(tty
, driver
, idx
);
1418 retval
= tty_driver_install_tty(driver
, tty
);
1420 goto err_deinit_tty
;
1423 * Structures all installed ... call the ldisc open routines.
1424 * If we fail here just call release_tty to clean up. No need
1425 * to decrement the use counts, as release_tty doesn't care.
1427 retval
= tty_ldisc_setup(tty
, tty
->link
);
1429 goto err_release_tty
;
1433 deinitialize_tty_struct(tty
);
1434 free_tty_struct(tty
);
1436 module_put(driver
->owner
);
1437 return ERR_PTR(retval
);
1439 /* call the tty release_tty routine to clean out this slot */
1441 if (printk_ratelimit())
1442 printk(KERN_INFO
"tty_init_dev: ldisc open failed, "
1443 "clearing slot %d\n", idx
);
1444 release_tty(tty
, idx
);
1445 return ERR_PTR(retval
);
1448 void tty_free_termios(struct tty_struct
*tty
)
1450 struct ktermios
*tp
;
1451 int idx
= tty
->index
;
1452 /* Kill this flag and push into drivers for locking etc */
1453 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
1454 /* FIXME: Locking on ->termios array */
1456 tty
->driver
->termios
[idx
] = NULL
;
1460 EXPORT_SYMBOL(tty_free_termios
);
1462 void tty_shutdown(struct tty_struct
*tty
)
1464 tty_driver_remove_tty(tty
->driver
, tty
);
1465 tty_free_termios(tty
);
1467 EXPORT_SYMBOL(tty_shutdown
);
1470 * release_one_tty - release tty structure memory
1471 * @kref: kref of tty we are obliterating
1473 * Releases memory associated with a tty structure, and clears out the
1474 * driver table slots. This function is called when a device is no longer
1475 * in use. It also gets called when setup of a device fails.
1478 * tty_mutex - sometimes only
1479 * takes the file list lock internally when working on the list
1480 * of ttys that the driver keeps.
1482 * This method gets called from a work queue so that the driver private
1483 * cleanup ops can sleep (needed for USB at least)
1485 static void release_one_tty(struct work_struct
*work
)
1487 struct tty_struct
*tty
=
1488 container_of(work
, struct tty_struct
, hangup_work
);
1489 struct tty_driver
*driver
= tty
->driver
;
1491 if (tty
->ops
->cleanup
)
1492 tty
->ops
->cleanup(tty
);
1495 tty_driver_kref_put(driver
);
1496 module_put(driver
->owner
);
1498 spin_lock(&tty_files_lock
);
1499 list_del_init(&tty
->tty_files
);
1500 spin_unlock(&tty_files_lock
);
1503 put_pid(tty
->session
);
1504 free_tty_struct(tty
);
1507 static void queue_release_one_tty(struct kref
*kref
)
1509 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1511 if (tty
->ops
->shutdown
)
1512 tty
->ops
->shutdown(tty
);
1516 /* The hangup queue is now free so we can reuse it rather than
1517 waste a chunk of memory for each port */
1518 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1519 schedule_work(&tty
->hangup_work
);
1523 * tty_kref_put - release a tty kref
1526 * Release a reference to a tty device and if need be let the kref
1527 * layer destruct the object for us
1530 void tty_kref_put(struct tty_struct
*tty
)
1533 kref_put(&tty
->kref
, queue_release_one_tty
);
1535 EXPORT_SYMBOL(tty_kref_put
);
1538 * release_tty - release tty structure memory
1540 * Release both @tty and a possible linked partner (think pty pair),
1541 * and decrement the refcount of the backing module.
1544 * tty_mutex - sometimes only
1545 * takes the file list lock internally when working on the list
1546 * of ttys that the driver keeps.
1547 * FIXME: should we require tty_mutex is held here ??
1550 static void release_tty(struct tty_struct
*tty
, int idx
)
1552 /* This should always be true but check for the moment */
1553 WARN_ON(tty
->index
!= idx
);
1556 tty_kref_put(tty
->link
);
1561 * tty_release - vfs callback for close
1562 * @inode: inode of tty
1563 * @filp: file pointer for handle to tty
1565 * Called the last time each file handle is closed that references
1566 * this tty. There may however be several such references.
1569 * Takes bkl. See tty_release_dev
1571 * Even releasing the tty structures is a tricky business.. We have
1572 * to be very careful that the structures are all released at the
1573 * same time, as interrupts might otherwise get the wrong pointers.
1575 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1576 * lead to double frees or releasing memory still in use.
1579 int tty_release(struct inode
*inode
, struct file
*filp
)
1581 struct tty_struct
*tty
= file_tty(filp
);
1582 struct tty_struct
*o_tty
;
1583 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1588 if (tty_paranoia_check(tty
, inode
, "tty_release_dev"))
1592 check_tty_count(tty
, "tty_release_dev");
1594 __tty_fasync(-1, filp
, 0);
1597 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1598 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1599 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
1602 #ifdef TTY_PARANOIA_CHECK
1603 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1604 printk(KERN_DEBUG
"tty_release_dev: bad idx when trying to "
1605 "free (%s)\n", tty
->name
);
1610 if (tty
!= tty
->driver
->ttys
[idx
]) {
1612 printk(KERN_DEBUG
"tty_release_dev: driver.table[%d] not tty "
1613 "for (%s)\n", idx
, tty
->name
);
1616 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
1618 printk(KERN_DEBUG
"tty_release_dev: driver.termios[%d] not termios "
1626 #ifdef TTY_DEBUG_HANGUP
1627 printk(KERN_DEBUG
"tty_release_dev of %s (tty count=%d)...",
1628 tty_name(tty
, buf
), tty
->count
);
1631 #ifdef TTY_PARANOIA_CHECK
1632 if (tty
->driver
->other
&&
1633 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
1634 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1636 printk(KERN_DEBUG
"tty_release_dev: other->table[%d] "
1637 "not o_tty for (%s)\n",
1641 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
1643 printk(KERN_DEBUG
"tty_release_dev: other->termios[%d] "
1644 "not o_termios for (%s)\n",
1648 if (o_tty
->link
!= tty
) {
1650 printk(KERN_DEBUG
"tty_release_dev: bad pty pointers\n");
1655 if (tty
->ops
->close
)
1656 tty
->ops
->close(tty
, filp
);
1660 * Sanity check: if tty->count is going to zero, there shouldn't be
1661 * any waiters on tty->read_wait or tty->write_wait. We test the
1662 * wait queues and kick everyone out _before_ actually starting to
1663 * close. This ensures that we won't block while releasing the tty
1666 * The test for the o_tty closing is necessary, since the master and
1667 * slave sides may close in any order. If the slave side closes out
1668 * first, its count will be one, since the master side holds an open.
1669 * Thus this test wouldn't be triggered at the time the slave closes,
1672 * Note that it's possible for the tty to be opened again while we're
1673 * flushing out waiters. By recalculating the closing flags before
1674 * each iteration we avoid any problems.
1677 /* Guard against races with tty->count changes elsewhere and
1678 opens on /dev/tty */
1680 mutex_lock(&tty_mutex
);
1682 tty_closing
= tty
->count
<= 1;
1683 o_tty_closing
= o_tty
&&
1684 (o_tty
->count
<= (pty_master
? 1 : 0));
1688 if (waitqueue_active(&tty
->read_wait
)) {
1689 wake_up_poll(&tty
->read_wait
, POLLIN
);
1692 if (waitqueue_active(&tty
->write_wait
)) {
1693 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1697 if (o_tty_closing
) {
1698 if (waitqueue_active(&o_tty
->read_wait
)) {
1699 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1702 if (waitqueue_active(&o_tty
->write_wait
)) {
1703 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1710 printk(KERN_WARNING
"tty_release_dev: %s: read/write wait queue "
1711 "active!\n", tty_name(tty
, buf
));
1713 mutex_unlock(&tty_mutex
);
1718 * The closing flags are now consistent with the open counts on
1719 * both sides, and we've completed the last operation that could
1720 * block, so it's safe to proceed with closing.
1723 if (--o_tty
->count
< 0) {
1724 printk(KERN_WARNING
"tty_release_dev: bad pty slave count "
1726 o_tty
->count
, tty_name(o_tty
, buf
));
1730 if (--tty
->count
< 0) {
1731 printk(KERN_WARNING
"tty_release_dev: bad tty->count (%d) for %s\n",
1732 tty
->count
, tty_name(tty
, buf
));
1737 * We've decremented tty->count, so we need to remove this file
1738 * descriptor off the tty->tty_files list; this serves two
1740 * - check_tty_count sees the correct number of file descriptors
1741 * associated with this tty.
1742 * - do_tty_hangup no longer sees this file descriptor as
1743 * something that needs to be handled for hangups.
1748 * Perform some housekeeping before deciding whether to return.
1750 * Set the TTY_CLOSING flag if this was the last open. In the
1751 * case of a pty we may have to wait around for the other side
1752 * to close, and TTY_CLOSING makes sure we can't be reopened.
1755 set_bit(TTY_CLOSING
, &tty
->flags
);
1757 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1760 * If _either_ side is closing, make sure there aren't any
1761 * processes that still think tty or o_tty is their controlling
1764 if (tty_closing
|| o_tty_closing
) {
1765 read_lock(&tasklist_lock
);
1766 session_clear_tty(tty
->session
);
1768 session_clear_tty(o_tty
->session
);
1769 read_unlock(&tasklist_lock
);
1772 mutex_unlock(&tty_mutex
);
1774 /* check whether both sides are closing ... */
1775 if (!tty_closing
|| (o_tty
&& !o_tty_closing
)) {
1780 #ifdef TTY_DEBUG_HANGUP
1781 printk(KERN_DEBUG
"freeing tty structure...");
1784 * Ask the line discipline code to release its structures
1786 tty_ldisc_release(tty
, o_tty
);
1788 * The release_tty function takes care of the details of clearing
1789 * the slots and preserving the termios structure.
1791 release_tty(tty
, idx
);
1793 /* Make this pty number available for reallocation */
1795 devpts_kill_index(inode
, idx
);
1801 * tty_open - open a tty device
1802 * @inode: inode of device file
1803 * @filp: file pointer to tty
1805 * tty_open and tty_release keep up the tty count that contains the
1806 * number of opens done on a tty. We cannot use the inode-count, as
1807 * different inodes might point to the same tty.
1809 * Open-counting is needed for pty masters, as well as for keeping
1810 * track of serial lines: DTR is dropped when the last close happens.
1811 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1813 * The termios state of a pty is reset on first open so that
1814 * settings don't persist across reuse.
1816 * Locking: tty_mutex protects tty, get_tty_driver and tty_init_dev work.
1817 * tty->count should protect the rest.
1818 * ->siglock protects ->signal/->sighand
1821 static int tty_open(struct inode
*inode
, struct file
*filp
)
1823 struct tty_struct
*tty
= NULL
;
1825 struct tty_driver
*driver
;
1827 dev_t device
= inode
->i_rdev
;
1828 unsigned saved_flags
= filp
->f_flags
;
1830 nonseekable_open(inode
, filp
);
1833 retval
= tty_alloc_file(filp
);
1837 noctty
= filp
->f_flags
& O_NOCTTY
;
1841 mutex_lock(&tty_mutex
);
1844 if (device
== MKDEV(TTYAUX_MAJOR
, 0)) {
1845 tty
= get_current_tty();
1848 mutex_unlock(&tty_mutex
);
1849 tty_free_file(filp
);
1852 driver
= tty_driver_kref_get(tty
->driver
);
1854 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1856 /* FIXME: Should we take a driver reference ? */
1861 if (device
== MKDEV(TTY_MAJOR
, 0)) {
1862 extern struct tty_driver
*console_driver
;
1863 driver
= tty_driver_kref_get(console_driver
);
1869 if (device
== MKDEV(TTYAUX_MAJOR
, 1)) {
1870 struct tty_driver
*console_driver
= console_device(&index
);
1871 if (console_driver
) {
1872 driver
= tty_driver_kref_get(console_driver
);
1874 /* Don't let /dev/console block */
1875 filp
->f_flags
|= O_NONBLOCK
;
1881 mutex_unlock(&tty_mutex
);
1882 tty_free_file(filp
);
1886 driver
= get_tty_driver(device
, &index
);
1889 mutex_unlock(&tty_mutex
);
1890 tty_free_file(filp
);
1895 /* check whether we're reopening an existing tty */
1896 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
1900 mutex_unlock(&tty_mutex
);
1901 tty_driver_kref_put(driver
);
1902 tty_free_file(filp
);
1903 return PTR_ERR(tty
);
1908 retval
= tty_reopen(tty
);
1910 tty
= ERR_PTR(retval
);
1912 tty
= tty_init_dev(driver
, index
, 0);
1914 mutex_unlock(&tty_mutex
);
1915 tty_driver_kref_put(driver
);
1918 tty_free_file(filp
);
1919 return PTR_ERR(tty
);
1922 tty_add_file(tty
, filp
);
1924 check_tty_count(tty
, "tty_open");
1925 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1926 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1928 #ifdef TTY_DEBUG_HANGUP
1929 printk(KERN_DEBUG
"opening %s...", tty
->name
);
1932 retval
= tty
->ops
->open(tty
, filp
);
1935 filp
->f_flags
= saved_flags
;
1937 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1938 !capable(CAP_SYS_ADMIN
))
1942 #ifdef TTY_DEBUG_HANGUP
1943 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
1946 tty_unlock(); /* need to call tty_release without BTM */
1947 tty_release(inode
, filp
);
1948 if (retval
!= -ERESTARTSYS
)
1951 if (signal_pending(current
))
1956 * Need to reset f_op in case a hangup happened.
1959 if (filp
->f_op
== &hung_up_tty_fops
)
1960 filp
->f_op
= &tty_fops
;
1967 mutex_lock(&tty_mutex
);
1969 spin_lock_irq(¤t
->sighand
->siglock
);
1971 current
->signal
->leader
&&
1972 !current
->signal
->tty
&&
1973 tty
->session
== NULL
)
1974 __proc_set_tty(current
, tty
);
1975 spin_unlock_irq(¤t
->sighand
->siglock
);
1977 mutex_unlock(&tty_mutex
);
1984 * tty_poll - check tty status
1985 * @filp: file being polled
1986 * @wait: poll wait structures to update
1988 * Call the line discipline polling method to obtain the poll
1989 * status of the device.
1991 * Locking: locks called line discipline but ldisc poll method
1992 * may be re-entered freely by other callers.
1995 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
1997 struct tty_struct
*tty
= file_tty(filp
);
1998 struct tty_ldisc
*ld
;
2001 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2004 ld
= tty_ldisc_ref_wait(tty
);
2006 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
2007 tty_ldisc_deref(ld
);
2011 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2013 struct tty_struct
*tty
= file_tty(filp
);
2014 unsigned long flags
;
2017 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2020 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2027 if (!waitqueue_active(&tty
->read_wait
))
2028 tty
->minimum_to_wake
= 1;
2029 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2032 type
= PIDTYPE_PGID
;
2034 pid
= task_pid(current
);
2038 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2039 retval
= __f_setown(filp
, pid
, type
, 0);
2044 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2045 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2052 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2056 retval
= __tty_fasync(fd
, filp
, on
);
2062 * tiocsti - fake input character
2063 * @tty: tty to fake input into
2064 * @p: pointer to character
2066 * Fake input to a tty device. Does the necessary locking and
2069 * FIXME: does not honour flow control ??
2072 * Called functions take tty_ldisc_lock
2073 * current->signal->tty check is safe without locks
2075 * FIXME: may race normal receive processing
2078 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2081 struct tty_ldisc
*ld
;
2083 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2085 if (get_user(ch
, p
))
2087 tty_audit_tiocsti(tty
, ch
);
2088 ld
= tty_ldisc_ref_wait(tty
);
2089 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2090 tty_ldisc_deref(ld
);
2095 * tiocgwinsz - implement window query ioctl
2097 * @arg: user buffer for result
2099 * Copies the kernel idea of the window size into the user buffer.
2101 * Locking: tty->termios_mutex is taken to ensure the winsize data
2105 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2109 mutex_lock(&tty
->termios_mutex
);
2110 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2111 mutex_unlock(&tty
->termios_mutex
);
2113 return err
? -EFAULT
: 0;
2117 * tty_do_resize - resize event
2118 * @tty: tty being resized
2119 * @rows: rows (character)
2120 * @cols: cols (character)
2122 * Update the termios variables and send the necessary signals to
2123 * peform a terminal resize correctly
2126 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2129 unsigned long flags
;
2132 mutex_lock(&tty
->termios_mutex
);
2133 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2135 /* Get the PID values and reference them so we can
2136 avoid holding the tty ctrl lock while sending signals */
2137 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2138 pgrp
= get_pid(tty
->pgrp
);
2139 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2142 kill_pgrp(pgrp
, SIGWINCH
, 1);
2147 mutex_unlock(&tty
->termios_mutex
);
2152 * tiocswinsz - implement window size set ioctl
2153 * @tty; tty side of tty
2154 * @arg: user buffer for result
2156 * Copies the user idea of the window size to the kernel. Traditionally
2157 * this is just advisory information but for the Linux console it
2158 * actually has driver level meaning and triggers a VC resize.
2161 * Driver dependent. The default do_resize method takes the
2162 * tty termios mutex and ctrl_lock. The console takes its own lock
2163 * then calls into the default method.
2166 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2168 struct winsize tmp_ws
;
2169 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2172 if (tty
->ops
->resize
)
2173 return tty
->ops
->resize(tty
, &tmp_ws
);
2175 return tty_do_resize(tty
, &tmp_ws
);
2179 * tioccons - allow admin to move logical console
2180 * @file: the file to become console
2182 * Allow the administrator to move the redirected console device
2184 * Locking: uses redirect_lock to guard the redirect information
2187 static int tioccons(struct file
*file
)
2189 if (!capable(CAP_SYS_ADMIN
))
2191 if (file
->f_op
->write
== redirected_tty_write
) {
2193 spin_lock(&redirect_lock
);
2196 spin_unlock(&redirect_lock
);
2201 spin_lock(&redirect_lock
);
2203 spin_unlock(&redirect_lock
);
2208 spin_unlock(&redirect_lock
);
2213 * fionbio - non blocking ioctl
2214 * @file: file to set blocking value
2215 * @p: user parameter
2217 * Historical tty interfaces had a blocking control ioctl before
2218 * the generic functionality existed. This piece of history is preserved
2219 * in the expected tty API of posix OS's.
2221 * Locking: none, the open file handle ensures it won't go away.
2224 static int fionbio(struct file
*file
, int __user
*p
)
2228 if (get_user(nonblock
, p
))
2231 spin_lock(&file
->f_lock
);
2233 file
->f_flags
|= O_NONBLOCK
;
2235 file
->f_flags
&= ~O_NONBLOCK
;
2236 spin_unlock(&file
->f_lock
);
2241 * tiocsctty - set controlling tty
2242 * @tty: tty structure
2243 * @arg: user argument
2245 * This ioctl is used to manage job control. It permits a session
2246 * leader to set this tty as the controlling tty for the session.
2249 * Takes tty_mutex() to protect tty instance
2250 * Takes tasklist_lock internally to walk sessions
2251 * Takes ->siglock() when updating signal->tty
2254 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2257 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2260 mutex_lock(&tty_mutex
);
2262 * The process must be a session leader and
2263 * not have a controlling tty already.
2265 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2272 * This tty is already the controlling
2273 * tty for another session group!
2275 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2279 read_lock(&tasklist_lock
);
2280 session_clear_tty(tty
->session
);
2281 read_unlock(&tasklist_lock
);
2287 proc_set_tty(current
, tty
);
2289 mutex_unlock(&tty_mutex
);
2294 * tty_get_pgrp - return a ref counted pgrp pid
2297 * Returns a refcounted instance of the pid struct for the process
2298 * group controlling the tty.
2301 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2303 unsigned long flags
;
2306 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2307 pgrp
= get_pid(tty
->pgrp
);
2308 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2312 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2315 * tiocgpgrp - get process group
2316 * @tty: tty passed by user
2317 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2320 * Obtain the process group of the tty. If there is no process group
2323 * Locking: none. Reference to current->signal->tty is safe.
2326 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2331 * (tty == real_tty) is a cheap way of
2332 * testing if the tty is NOT a master pty.
2334 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2336 pid
= tty_get_pgrp(real_tty
);
2337 ret
= put_user(pid_vnr(pid
), p
);
2343 * tiocspgrp - attempt to set process group
2344 * @tty: tty passed by user
2345 * @real_tty: tty side device matching tty passed by user
2348 * Set the process group of the tty to the session passed. Only
2349 * permitted where the tty session is our session.
2351 * Locking: RCU, ctrl lock
2354 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2358 int retval
= tty_check_change(real_tty
);
2359 unsigned long flags
;
2365 if (!current
->signal
->tty
||
2366 (current
->signal
->tty
!= real_tty
) ||
2367 (real_tty
->session
!= task_session(current
)))
2369 if (get_user(pgrp_nr
, p
))
2374 pgrp
= find_vpid(pgrp_nr
);
2379 if (session_of_pgrp(pgrp
) != task_session(current
))
2382 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2383 put_pid(real_tty
->pgrp
);
2384 real_tty
->pgrp
= get_pid(pgrp
);
2385 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2392 * tiocgsid - get session id
2393 * @tty: tty passed by user
2394 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2395 * @p: pointer to returned session id
2397 * Obtain the session id of the tty. If there is no session
2400 * Locking: none. Reference to current->signal->tty is safe.
2403 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2406 * (tty == real_tty) is a cheap way of
2407 * testing if the tty is NOT a master pty.
2409 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2411 if (!real_tty
->session
)
2413 return put_user(pid_vnr(real_tty
->session
), p
);
2417 * tiocsetd - set line discipline
2419 * @p: pointer to user data
2421 * Set the line discipline according to user request.
2423 * Locking: see tty_set_ldisc, this function is just a helper
2426 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2431 if (get_user(ldisc
, p
))
2434 ret
= tty_set_ldisc(tty
, ldisc
);
2440 * send_break - performed time break
2441 * @tty: device to break on
2442 * @duration: timeout in mS
2444 * Perform a timed break on hardware that lacks its own driver level
2445 * timed break functionality.
2448 * atomic_write_lock serializes
2452 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2456 if (tty
->ops
->break_ctl
== NULL
)
2459 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2460 retval
= tty
->ops
->break_ctl(tty
, duration
);
2462 /* Do the work ourselves */
2463 if (tty_write_lock(tty
, 0) < 0)
2465 retval
= tty
->ops
->break_ctl(tty
, -1);
2468 if (!signal_pending(current
))
2469 msleep_interruptible(duration
);
2470 retval
= tty
->ops
->break_ctl(tty
, 0);
2472 tty_write_unlock(tty
);
2473 if (signal_pending(current
))
2480 * tty_tiocmget - get modem status
2482 * @file: user file pointer
2483 * @p: pointer to result
2485 * Obtain the modem status bits from the tty driver if the feature
2486 * is supported. Return -EINVAL if it is not available.
2488 * Locking: none (up to the driver)
2491 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2493 int retval
= -EINVAL
;
2495 if (tty
->ops
->tiocmget
) {
2496 retval
= tty
->ops
->tiocmget(tty
);
2499 retval
= put_user(retval
, p
);
2505 * tty_tiocmset - set modem status
2507 * @cmd: command - clear bits, set bits or set all
2508 * @p: pointer to desired bits
2510 * Set the modem status bits from the tty driver if the feature
2511 * is supported. Return -EINVAL if it is not available.
2513 * Locking: none (up to the driver)
2516 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2520 unsigned int set
, clear
, val
;
2522 if (tty
->ops
->tiocmset
== NULL
)
2525 retval
= get_user(val
, p
);
2541 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2542 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2543 return tty
->ops
->tiocmset(tty
, set
, clear
);
2546 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2548 int retval
= -EINVAL
;
2549 struct serial_icounter_struct icount
;
2550 memset(&icount
, 0, sizeof(icount
));
2551 if (tty
->ops
->get_icount
)
2552 retval
= tty
->ops
->get_icount(tty
, &icount
);
2555 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2560 struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2562 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2563 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2567 EXPORT_SYMBOL(tty_pair_get_tty
);
2569 struct tty_struct
*tty_pair_get_pty(struct tty_struct
*tty
)
2571 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2572 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2576 EXPORT_SYMBOL(tty_pair_get_pty
);
2579 * Split this up, as gcc can choke on it otherwise..
2581 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2583 struct tty_struct
*tty
= file_tty(file
);
2584 struct tty_struct
*real_tty
;
2585 void __user
*p
= (void __user
*)arg
;
2587 struct tty_ldisc
*ld
;
2588 struct inode
*inode
= file
->f_dentry
->d_inode
;
2590 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2593 real_tty
= tty_pair_get_tty(tty
);
2596 * Factor out some common prep work
2604 retval
= tty_check_change(tty
);
2607 if (cmd
!= TIOCCBRK
) {
2608 tty_wait_until_sent(tty
, 0);
2609 if (signal_pending(current
))
2620 return tiocsti(tty
, p
);
2622 return tiocgwinsz(real_tty
, p
);
2624 return tiocswinsz(real_tty
, p
);
2626 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2628 return fionbio(file
, p
);
2630 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2633 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2636 if (current
->signal
->tty
!= tty
)
2641 return tiocsctty(tty
, arg
);
2643 return tiocgpgrp(tty
, real_tty
, p
);
2645 return tiocspgrp(tty
, real_tty
, p
);
2647 return tiocgsid(tty
, real_tty
, p
);
2649 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2651 return tiocsetd(tty
, p
);
2653 if (!capable(CAP_SYS_ADMIN
))
2659 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2660 return put_user(ret
, (unsigned int __user
*)p
);
2665 case TIOCSBRK
: /* Turn break on, unconditionally */
2666 if (tty
->ops
->break_ctl
)
2667 return tty
->ops
->break_ctl(tty
, -1);
2669 case TIOCCBRK
: /* Turn break off, unconditionally */
2670 if (tty
->ops
->break_ctl
)
2671 return tty
->ops
->break_ctl(tty
, 0);
2673 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2674 /* non-zero arg means wait for all output data
2675 * to be sent (performed above) but don't send break.
2676 * This is used by the tcdrain() termios function.
2679 return send_break(tty
, 250);
2681 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2682 return send_break(tty
, arg
? arg
*100 : 250);
2685 return tty_tiocmget(tty
, p
);
2689 return tty_tiocmset(tty
, cmd
, p
);
2691 retval
= tty_tiocgicount(tty
, p
);
2692 /* For the moment allow fall through to the old method */
2693 if (retval
!= -EINVAL
)
2700 /* flush tty buffer and allow ldisc to process ioctl */
2701 tty_buffer_flush(tty
);
2706 if (tty
->ops
->ioctl
) {
2707 retval
= (tty
->ops
->ioctl
)(tty
, cmd
, arg
);
2708 if (retval
!= -ENOIOCTLCMD
)
2711 ld
= tty_ldisc_ref_wait(tty
);
2713 if (ld
->ops
->ioctl
) {
2714 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2715 if (retval
== -ENOIOCTLCMD
)
2718 tty_ldisc_deref(ld
);
2722 #ifdef CONFIG_COMPAT
2723 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2726 struct inode
*inode
= file
->f_dentry
->d_inode
;
2727 struct tty_struct
*tty
= file_tty(file
);
2728 struct tty_ldisc
*ld
;
2729 int retval
= -ENOIOCTLCMD
;
2731 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2734 if (tty
->ops
->compat_ioctl
) {
2735 retval
= (tty
->ops
->compat_ioctl
)(tty
, cmd
, arg
);
2736 if (retval
!= -ENOIOCTLCMD
)
2740 ld
= tty_ldisc_ref_wait(tty
);
2741 if (ld
->ops
->compat_ioctl
)
2742 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2743 tty_ldisc_deref(ld
);
2750 * This implements the "Secure Attention Key" --- the idea is to
2751 * prevent trojan horses by killing all processes associated with this
2752 * tty when the user hits the "Secure Attention Key". Required for
2753 * super-paranoid applications --- see the Orange Book for more details.
2755 * This code could be nicer; ideally it should send a HUP, wait a few
2756 * seconds, then send a INT, and then a KILL signal. But you then
2757 * have to coordinate with the init process, since all processes associated
2758 * with the current tty must be dead before the new getty is allowed
2761 * Now, if it would be correct ;-/ The current code has a nasty hole -
2762 * it doesn't catch files in flight. We may send the descriptor to ourselves
2763 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2765 * Nasty bug: do_SAK is being called in interrupt context. This can
2766 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2768 void __do_SAK(struct tty_struct
*tty
)
2773 struct task_struct
*g
, *p
;
2774 struct pid
*session
;
2777 struct fdtable
*fdt
;
2781 session
= tty
->session
;
2783 tty_ldisc_flush(tty
);
2785 tty_driver_flush_buffer(tty
);
2787 read_lock(&tasklist_lock
);
2788 /* Kill the entire session */
2789 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2790 printk(KERN_NOTICE
"SAK: killed process %d"
2791 " (%s): task_session(p)==tty->session\n",
2792 task_pid_nr(p
), p
->comm
);
2793 send_sig(SIGKILL
, p
, 1);
2794 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2795 /* Now kill any processes that happen to have the
2798 do_each_thread(g
, p
) {
2799 if (p
->signal
->tty
== tty
) {
2800 printk(KERN_NOTICE
"SAK: killed process %d"
2801 " (%s): task_session(p)==tty->session\n",
2802 task_pid_nr(p
), p
->comm
);
2803 send_sig(SIGKILL
, p
, 1);
2809 * We don't take a ref to the file, so we must
2810 * hold ->file_lock instead.
2812 spin_lock(&p
->files
->file_lock
);
2813 fdt
= files_fdtable(p
->files
);
2814 for (i
= 0; i
< fdt
->max_fds
; i
++) {
2815 filp
= fcheck_files(p
->files
, i
);
2818 if (filp
->f_op
->read
== tty_read
&&
2819 file_tty(filp
) == tty
) {
2820 printk(KERN_NOTICE
"SAK: killed process %d"
2821 " (%s): fd#%d opened to the tty\n",
2822 task_pid_nr(p
), p
->comm
, i
);
2823 force_sig(SIGKILL
, p
);
2827 spin_unlock(&p
->files
->file_lock
);
2830 } while_each_thread(g
, p
);
2831 read_unlock(&tasklist_lock
);
2835 static void do_SAK_work(struct work_struct
*work
)
2837 struct tty_struct
*tty
=
2838 container_of(work
, struct tty_struct
, SAK_work
);
2843 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2844 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2845 * the values which we write to it will be identical to the values which it
2846 * already has. --akpm
2848 void do_SAK(struct tty_struct
*tty
)
2852 schedule_work(&tty
->SAK_work
);
2855 EXPORT_SYMBOL(do_SAK
);
2857 static int dev_match_devt(struct device
*dev
, void *data
)
2860 return dev
->devt
== *devt
;
2863 /* Must put_device() after it's unused! */
2864 static struct device
*tty_get_device(struct tty_struct
*tty
)
2866 dev_t devt
= tty_devnum(tty
);
2867 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2872 * initialize_tty_struct
2873 * @tty: tty to initialize
2875 * This subroutine initializes a tty structure that has been newly
2878 * Locking: none - tty in question must not be exposed at this point
2881 void initialize_tty_struct(struct tty_struct
*tty
,
2882 struct tty_driver
*driver
, int idx
)
2884 memset(tty
, 0, sizeof(struct tty_struct
));
2885 kref_init(&tty
->kref
);
2886 tty
->magic
= TTY_MAGIC
;
2887 tty_ldisc_init(tty
);
2888 tty
->session
= NULL
;
2890 tty
->overrun_time
= jiffies
;
2891 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
2892 tty_buffer_init(tty
);
2893 mutex_init(&tty
->termios_mutex
);
2894 mutex_init(&tty
->ldisc_mutex
);
2895 init_waitqueue_head(&tty
->write_wait
);
2896 init_waitqueue_head(&tty
->read_wait
);
2897 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2898 mutex_init(&tty
->atomic_read_lock
);
2899 mutex_init(&tty
->atomic_write_lock
);
2900 mutex_init(&tty
->output_lock
);
2901 mutex_init(&tty
->echo_lock
);
2902 spin_lock_init(&tty
->read_lock
);
2903 spin_lock_init(&tty
->ctrl_lock
);
2904 INIT_LIST_HEAD(&tty
->tty_files
);
2905 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2907 tty
->driver
= driver
;
2908 tty
->ops
= driver
->ops
;
2910 tty_line_name(driver
, idx
, tty
->name
);
2911 tty
->dev
= tty_get_device(tty
);
2915 * deinitialize_tty_struct
2916 * @tty: tty to deinitialize
2918 * This subroutine deinitializes a tty structure that has been newly
2919 * allocated but tty_release cannot be called on that yet.
2921 * Locking: none - tty in question must not be exposed at this point
2923 void deinitialize_tty_struct(struct tty_struct
*tty
)
2925 tty_ldisc_deinit(tty
);
2929 * tty_put_char - write one character to a tty
2933 * Write one byte to the tty using the provided put_char method
2934 * if present. Returns the number of characters successfully output.
2936 * Note: the specific put_char operation in the driver layer may go
2937 * away soon. Don't call it directly, use this method
2940 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2942 if (tty
->ops
->put_char
)
2943 return tty
->ops
->put_char(tty
, ch
);
2944 return tty
->ops
->write(tty
, &ch
, 1);
2946 EXPORT_SYMBOL_GPL(tty_put_char
);
2948 struct class *tty_class
;
2951 * tty_register_device - register a tty device
2952 * @driver: the tty driver that describes the tty device
2953 * @index: the index in the tty driver for this tty device
2954 * @device: a struct device that is associated with this tty device.
2955 * This field is optional, if there is no known struct device
2956 * for this tty device it can be set to NULL safely.
2958 * Returns a pointer to the struct device for this tty device
2959 * (or ERR_PTR(-EFOO) on error).
2961 * This call is required to be made to register an individual tty device
2962 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
2963 * that bit is not set, this function should not be called by a tty
2969 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
2970 struct device
*device
)
2973 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
2975 if (index
>= driver
->num
) {
2976 printk(KERN_ERR
"Attempt to register invalid tty line number "
2978 return ERR_PTR(-EINVAL
);
2981 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
2982 pty_line_name(driver
, index
, name
);
2984 tty_line_name(driver
, index
, name
);
2986 return device_create(tty_class
, device
, dev
, NULL
, name
);
2988 EXPORT_SYMBOL(tty_register_device
);
2991 * tty_unregister_device - unregister a tty device
2992 * @driver: the tty driver that describes the tty device
2993 * @index: the index in the tty driver for this tty device
2995 * If a tty device is registered with a call to tty_register_device() then
2996 * this function must be called when the tty device is gone.
3001 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3003 device_destroy(tty_class
,
3004 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3006 EXPORT_SYMBOL(tty_unregister_device
);
3008 struct tty_driver
*alloc_tty_driver(int lines
)
3010 struct tty_driver
*driver
;
3012 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3014 kref_init(&driver
->kref
);
3015 driver
->magic
= TTY_DRIVER_MAGIC
;
3016 driver
->num
= lines
;
3017 /* later we'll move allocation of tables here */
3021 EXPORT_SYMBOL(alloc_tty_driver
);
3023 static void destruct_tty_driver(struct kref
*kref
)
3025 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3027 struct ktermios
*tp
;
3030 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3032 * Free the termios and termios_locked structures because
3033 * we don't want to get memory leaks when modular tty
3034 * drivers are removed from the kernel.
3036 for (i
= 0; i
< driver
->num
; i
++) {
3037 tp
= driver
->termios
[i
];
3039 driver
->termios
[i
] = NULL
;
3042 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3043 tty_unregister_device(driver
, i
);
3046 proc_tty_unregister_driver(driver
);
3047 driver
->ttys
= NULL
;
3048 driver
->termios
= NULL
;
3050 cdev_del(&driver
->cdev
);
3055 void tty_driver_kref_put(struct tty_driver
*driver
)
3057 kref_put(&driver
->kref
, destruct_tty_driver
);
3059 EXPORT_SYMBOL(tty_driver_kref_put
);
3061 void tty_set_operations(struct tty_driver
*driver
,
3062 const struct tty_operations
*op
)
3066 EXPORT_SYMBOL(tty_set_operations
);
3068 void put_tty_driver(struct tty_driver
*d
)
3070 tty_driver_kref_put(d
);
3072 EXPORT_SYMBOL(put_tty_driver
);
3075 * Called by a tty driver to register itself.
3077 int tty_register_driver(struct tty_driver
*driver
)
3085 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
3086 p
= kzalloc(driver
->num
* 2 * sizeof(void *), GFP_KERNEL
);
3091 if (!driver
->major
) {
3092 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3093 driver
->num
, driver
->name
);
3095 driver
->major
= MAJOR(dev
);
3096 driver
->minor_start
= MINOR(dev
);
3099 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3100 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3108 driver
->ttys
= (struct tty_struct
**)p
;
3109 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
3111 driver
->ttys
= NULL
;
3112 driver
->termios
= NULL
;
3115 cdev_init(&driver
->cdev
, &tty_fops
);
3116 driver
->cdev
.owner
= driver
->owner
;
3117 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
3119 unregister_chrdev_region(dev
, driver
->num
);
3120 driver
->ttys
= NULL
;
3121 driver
->termios
= NULL
;
3126 mutex_lock(&tty_mutex
);
3127 list_add(&driver
->tty_drivers
, &tty_drivers
);
3128 mutex_unlock(&tty_mutex
);
3130 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3131 for (i
= 0; i
< driver
->num
; i
++) {
3132 d
= tty_register_device(driver
, i
, NULL
);
3139 proc_tty_register_driver(driver
);
3140 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3144 for (i
--; i
>= 0; i
--)
3145 tty_unregister_device(driver
, i
);
3147 mutex_lock(&tty_mutex
);
3148 list_del(&driver
->tty_drivers
);
3149 mutex_unlock(&tty_mutex
);
3151 unregister_chrdev_region(dev
, driver
->num
);
3152 driver
->ttys
= NULL
;
3153 driver
->termios
= NULL
;
3158 EXPORT_SYMBOL(tty_register_driver
);
3161 * Called by a tty driver to unregister itself.
3163 int tty_unregister_driver(struct tty_driver
*driver
)
3167 if (driver
->refcount
)
3170 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3172 mutex_lock(&tty_mutex
);
3173 list_del(&driver
->tty_drivers
);
3174 mutex_unlock(&tty_mutex
);
3178 EXPORT_SYMBOL(tty_unregister_driver
);
3180 dev_t
tty_devnum(struct tty_struct
*tty
)
3182 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3184 EXPORT_SYMBOL(tty_devnum
);
3186 void proc_clear_tty(struct task_struct
*p
)
3188 unsigned long flags
;
3189 struct tty_struct
*tty
;
3190 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
3191 tty
= p
->signal
->tty
;
3192 p
->signal
->tty
= NULL
;
3193 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
3197 /* Called under the sighand lock */
3199 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3202 unsigned long flags
;
3203 /* We should not have a session or pgrp to put here but.... */
3204 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3205 put_pid(tty
->session
);
3207 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3208 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3209 tty
->session
= get_pid(task_session(tsk
));
3210 if (tsk
->signal
->tty
) {
3211 printk(KERN_DEBUG
"tty not NULL!!\n");
3212 tty_kref_put(tsk
->signal
->tty
);
3215 put_pid(tsk
->signal
->tty_old_pgrp
);
3216 tsk
->signal
->tty
= tty_kref_get(tty
);
3217 tsk
->signal
->tty_old_pgrp
= NULL
;
3220 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3222 spin_lock_irq(&tsk
->sighand
->siglock
);
3223 __proc_set_tty(tsk
, tty
);
3224 spin_unlock_irq(&tsk
->sighand
->siglock
);
3227 struct tty_struct
*get_current_tty(void)
3229 struct tty_struct
*tty
;
3230 unsigned long flags
;
3232 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
3233 tty
= tty_kref_get(current
->signal
->tty
);
3234 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
3237 EXPORT_SYMBOL_GPL(get_current_tty
);
3239 void tty_default_fops(struct file_operations
*fops
)
3245 * Initialize the console device. This is called *early*, so
3246 * we can't necessarily depend on lots of kernel help here.
3247 * Just do some early initializations, and do the complex setup
3250 void __init
console_init(void)
3254 /* Setup the default TTY line discipline. */
3258 * set up the console device so that later boot sequences can
3259 * inform about problems etc..
3261 call
= __con_initcall_start
;
3262 while (call
< __con_initcall_end
) {
3268 static char *tty_devnode(struct device
*dev
, mode_t
*mode
)
3272 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3273 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3278 static int __init
tty_class_init(void)
3280 tty_class
= class_create(THIS_MODULE
, "tty");
3281 if (IS_ERR(tty_class
))
3282 return PTR_ERR(tty_class
);
3283 tty_class
->devnode
= tty_devnode
;
3287 postcore_initcall(tty_class_init
);
3289 /* 3/2004 jmc: why do these devices exist? */
3290 static struct cdev tty_cdev
, console_cdev
;
3292 static ssize_t
show_cons_active(struct device
*dev
,
3293 struct device_attribute
*attr
, char *buf
)
3295 struct console
*cs
[16];
3301 for_each_console(c
) {
3306 if ((c
->flags
& CON_ENABLED
) == 0)
3309 if (i
>= ARRAY_SIZE(cs
))
3313 count
+= sprintf(buf
+ count
, "%s%d%c",
3314 cs
[i
]->name
, cs
[i
]->index
, i
? ' ':'\n');
3319 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3321 static struct device
*consdev
;
3323 void console_sysfs_notify(void)
3326 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3330 * Ok, now we can initialize the rest of the tty devices and can count
3331 * on memory allocations, interrupts etc..
3333 int __init
tty_init(void)
3335 cdev_init(&tty_cdev
, &tty_fops
);
3336 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3337 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3338 panic("Couldn't register /dev/tty driver\n");
3339 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3341 cdev_init(&console_cdev
, &console_fops
);
3342 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3343 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3344 panic("Couldn't register /dev/console driver\n");
3345 consdev
= device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3347 if (IS_ERR(consdev
))
3350 WARN_ON(device_create_file(consdev
, &dev_attr_active
) < 0);
3353 vty_init(&console_fops
);