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() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
68 #include <linux/types.h>
69 #include <linux/major.h>
70 #include <linux/errno.h>
71 #include <linux/signal.h>
72 #include <linux/fcntl.h>
73 #include <linux/sched.h>
74 #include <linux/interrupt.h>
75 #include <linux/tty.h>
76 #include <linux/tty_driver.h>
77 #include <linux/tty_flip.h>
78 #include <linux/devpts_fs.h>
79 #include <linux/file.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/smp_lock.h>
92 #include <linux/device.h>
93 #include <linux/idr.h>
94 #include <linux/wait.h>
95 #include <linux/bitops.h>
96 #include <linux/delay.h>
98 #include <asm/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>
107 #undef TTY_DEBUG_HANGUP
109 #define TTY_PARANOIA_CHECK 1
110 #define CHECK_TTY_COUNT 1
112 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
113 .c_iflag
= ICRNL
| IXON
,
114 .c_oflag
= OPOST
| ONLCR
,
115 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
116 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
117 ECHOCTL
| ECHOKE
| IEXTEN
,
123 EXPORT_SYMBOL(tty_std_termios
);
125 /* This list gets poked at by procfs and various bits of boot up code. This
126 could do with some rationalisation such as pulling the tty proc function
129 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
131 /* Mutex to protect creating and releasing a tty. This is shared with
132 vt.c for deeply disgusting hack reasons */
133 DEFINE_MUTEX(tty_mutex
);
134 EXPORT_SYMBOL(tty_mutex
);
136 #ifdef CONFIG_UNIX98_PTYS
137 extern struct tty_driver
*ptm_driver
; /* Unix98 pty masters; for /dev/ptmx */
138 extern int pty_limit
; /* Config limit on Unix98 ptys */
139 static DEFINE_IDR(allocated_ptys
);
140 static DECLARE_MUTEX(allocated_ptys_lock
);
141 static int ptmx_open(struct inode
*, struct file
*);
144 extern void disable_early_printk(void);
146 static void initialize_tty_struct(struct tty_struct
*tty
);
148 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
149 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
150 ssize_t
redirected_tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
151 static unsigned int tty_poll(struct file
*, poll_table
*);
152 static int tty_open(struct inode
*, struct file
*);
153 static int tty_release(struct inode
*, struct file
*);
154 int tty_ioctl(struct inode
* inode
, struct file
* file
,
155 unsigned int cmd
, unsigned long arg
);
156 static int tty_fasync(int fd
, struct file
* filp
, int on
);
157 static void release_tty(struct tty_struct
*tty
, int idx
);
158 static struct pid
*__proc_set_tty(struct task_struct
*tsk
,
159 struct tty_struct
*tty
);
162 * alloc_tty_struct - allocate a tty object
164 * Return a new empty tty structure. The data fields have not
165 * been initialized in any way but has been zeroed
170 static struct tty_struct
*alloc_tty_struct(void)
172 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
175 static void tty_buffer_free_all(struct tty_struct
*);
178 * free_tty_struct - free a disused tty
179 * @tty: tty struct to free
181 * Free the write buffers, tty queue and tty memory itself.
183 * Locking: none. Must be called after tty is definitely unused
186 static inline void free_tty_struct(struct tty_struct
*tty
)
188 kfree(tty
->write_buf
);
189 tty_buffer_free_all(tty
);
193 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
196 * tty_name - return tty naming
197 * @tty: tty structure
198 * @buf: buffer for output
200 * Convert a tty structure into a name. The name reflects the kernel
201 * naming policy and if udev is in use may not reflect user space
206 char *tty_name(struct tty_struct
*tty
, char *buf
)
208 if (!tty
) /* Hmm. NULL pointer. That's fun. */
209 strcpy(buf
, "NULL tty");
211 strcpy(buf
, tty
->name
);
215 EXPORT_SYMBOL(tty_name
);
217 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
220 #ifdef TTY_PARANOIA_CHECK
223 "null TTY for (%d:%d) in %s\n",
224 imajor(inode
), iminor(inode
), routine
);
227 if (tty
->magic
!= TTY_MAGIC
) {
229 "bad magic number for tty struct (%d:%d) in %s\n",
230 imajor(inode
), iminor(inode
), routine
);
237 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
239 #ifdef CHECK_TTY_COUNT
244 list_for_each(p
, &tty
->tty_files
) {
248 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
249 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
250 tty
->link
&& tty
->link
->count
)
252 if (tty
->count
!= count
) {
253 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
254 "!= #fd's(%d) in %s\n",
255 tty
->name
, tty
->count
, count
, routine
);
263 * Tty buffer allocation management
267 * tty_buffer_free_all - free buffers used by a tty
268 * @tty: tty to free from
270 * Remove all the buffers pending on a tty whether queued with data
271 * or in the free ring. Must be called when the tty is no longer in use
276 static void tty_buffer_free_all(struct tty_struct
*tty
)
278 struct tty_buffer
*thead
;
279 while((thead
= tty
->buf
.head
) != NULL
) {
280 tty
->buf
.head
= thead
->next
;
283 while((thead
= tty
->buf
.free
) != NULL
) {
284 tty
->buf
.free
= thead
->next
;
287 tty
->buf
.tail
= NULL
;
288 tty
->buf
.memory_used
= 0;
292 * tty_buffer_init - prepare a tty buffer structure
293 * @tty: tty to initialise
295 * Set up the initial state of the buffer management for a tty device.
296 * Must be called before the other tty buffer functions are used.
301 static void tty_buffer_init(struct tty_struct
*tty
)
303 spin_lock_init(&tty
->buf
.lock
);
304 tty
->buf
.head
= NULL
;
305 tty
->buf
.tail
= NULL
;
306 tty
->buf
.free
= NULL
;
307 tty
->buf
.memory_used
= 0;
311 * tty_buffer_alloc - allocate a tty buffer
313 * @size: desired size (characters)
315 * Allocate a new tty buffer to hold the desired number of characters.
316 * Return NULL if out of memory or the allocation would exceed the
319 * Locking: Caller must hold tty->buf.lock
322 static struct tty_buffer
*tty_buffer_alloc(struct tty_struct
*tty
, size_t size
)
324 struct tty_buffer
*p
;
326 if (tty
->buf
.memory_used
+ size
> 65536)
328 p
= kmalloc(sizeof(struct tty_buffer
) + 2 * size
, GFP_ATOMIC
);
336 p
->char_buf_ptr
= (char *)(p
->data
);
337 p
->flag_buf_ptr
= (unsigned char *)p
->char_buf_ptr
+ size
;
338 tty
->buf
.memory_used
+= size
;
343 * tty_buffer_free - free a tty buffer
344 * @tty: tty owning the buffer
345 * @b: the buffer to free
347 * Free a tty buffer, or add it to the free list according to our
350 * Locking: Caller must hold tty->buf.lock
353 static void tty_buffer_free(struct tty_struct
*tty
, struct tty_buffer
*b
)
355 /* Dumb strategy for now - should keep some stats */
356 tty
->buf
.memory_used
-= b
->size
;
357 WARN_ON(tty
->buf
.memory_used
< 0);
362 b
->next
= tty
->buf
.free
;
368 * tty_buffer_find - find a free tty buffer
369 * @tty: tty owning the buffer
370 * @size: characters wanted
372 * Locate an existing suitable tty buffer or if we are lacking one then
373 * allocate a new one. We round our buffers off in 256 character chunks
374 * to get better allocation behaviour.
376 * Locking: Caller must hold tty->buf.lock
379 static struct tty_buffer
*tty_buffer_find(struct tty_struct
*tty
, size_t size
)
381 struct tty_buffer
**tbh
= &tty
->buf
.free
;
382 while((*tbh
) != NULL
) {
383 struct tty_buffer
*t
= *tbh
;
384 if(t
->size
>= size
) {
390 tty
->buf
.memory_used
+= t
->size
;
393 tbh
= &((*tbh
)->next
);
395 /* Round the buffer size out */
396 size
= (size
+ 0xFF) & ~ 0xFF;
397 return tty_buffer_alloc(tty
, size
);
398 /* Should possibly check if this fails for the largest buffer we
399 have queued and recycle that ? */
403 * tty_buffer_request_room - grow tty buffer if needed
404 * @tty: tty structure
405 * @size: size desired
407 * Make at least size bytes of linear space available for the tty
408 * buffer. If we fail return the size we managed to find.
410 * Locking: Takes tty->buf.lock
412 int tty_buffer_request_room(struct tty_struct
*tty
, size_t size
)
414 struct tty_buffer
*b
, *n
;
418 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
420 /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
421 remove this conditional if its worth it. This would be invisible
423 if ((b
= tty
->buf
.tail
) != NULL
)
424 left
= b
->size
- b
->used
;
429 /* This is the slow path - looking for new buffers to use */
430 if ((n
= tty_buffer_find(tty
, size
)) != NULL
) {
441 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
444 EXPORT_SYMBOL_GPL(tty_buffer_request_room
);
447 * tty_insert_flip_string - Add characters to the tty buffer
448 * @tty: tty structure
452 * Queue a series of bytes to the tty buffering. All the characters
453 * passed are marked as without error. Returns the number added.
455 * Locking: Called functions may take tty->buf.lock
458 int tty_insert_flip_string(struct tty_struct
*tty
, const unsigned char *chars
,
463 int space
= tty_buffer_request_room(tty
, size
- copied
);
464 struct tty_buffer
*tb
= tty
->buf
.tail
;
465 /* If there is no space then tb may be NULL */
466 if(unlikely(space
== 0))
468 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
469 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
473 /* There is a small chance that we need to split the data over
474 several buffers. If this is the case we must loop */
475 } while (unlikely(size
> copied
));
478 EXPORT_SYMBOL(tty_insert_flip_string
);
481 * tty_insert_flip_string_flags - Add characters to the tty buffer
482 * @tty: tty structure
487 * Queue a series of bytes to the tty buffering. For each character
488 * the flags array indicates the status of the character. Returns the
491 * Locking: Called functions may take tty->buf.lock
494 int tty_insert_flip_string_flags(struct tty_struct
*tty
,
495 const unsigned char *chars
, const char *flags
, size_t size
)
499 int space
= tty_buffer_request_room(tty
, size
- copied
);
500 struct tty_buffer
*tb
= tty
->buf
.tail
;
501 /* If there is no space then tb may be NULL */
502 if(unlikely(space
== 0))
504 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
505 memcpy(tb
->flag_buf_ptr
+ tb
->used
, flags
, space
);
510 /* There is a small chance that we need to split the data over
511 several buffers. If this is the case we must loop */
512 } while (unlikely(size
> copied
));
515 EXPORT_SYMBOL(tty_insert_flip_string_flags
);
518 * tty_schedule_flip - push characters to ldisc
519 * @tty: tty to push from
521 * Takes any pending buffers and transfers their ownership to the
522 * ldisc side of the queue. It then schedules those characters for
523 * processing by the line discipline.
525 * Locking: Takes tty->buf.lock
528 void tty_schedule_flip(struct tty_struct
*tty
)
531 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
532 if (tty
->buf
.tail
!= NULL
)
533 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
534 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
535 schedule_delayed_work(&tty
->buf
.work
, 1);
537 EXPORT_SYMBOL(tty_schedule_flip
);
540 * tty_prepare_flip_string - make room for characters
542 * @chars: return pointer for character write area
543 * @size: desired size
545 * Prepare a block of space in the buffer for data. Returns the length
546 * available and buffer pointer to the space which is now allocated and
547 * accounted for as ready for normal characters. This is used for drivers
548 * that need their own block copy routines into the buffer. There is no
549 * guarantee the buffer is a DMA target!
551 * Locking: May call functions taking tty->buf.lock
554 int tty_prepare_flip_string(struct tty_struct
*tty
, unsigned char **chars
, size_t size
)
556 int space
= tty_buffer_request_room(tty
, size
);
558 struct tty_buffer
*tb
= tty
->buf
.tail
;
559 *chars
= tb
->char_buf_ptr
+ tb
->used
;
560 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
566 EXPORT_SYMBOL_GPL(tty_prepare_flip_string
);
569 * tty_prepare_flip_string_flags - make room for characters
571 * @chars: return pointer for character write area
572 * @flags: return pointer for status flag write area
573 * @size: desired size
575 * Prepare a block of space in the buffer for data. Returns the length
576 * available and buffer pointer to the space which is now allocated and
577 * accounted for as ready for characters. This is used for drivers
578 * that need their own block copy routines into the buffer. There is no
579 * guarantee the buffer is a DMA target!
581 * Locking: May call functions taking tty->buf.lock
584 int tty_prepare_flip_string_flags(struct tty_struct
*tty
, unsigned char **chars
, char **flags
, size_t size
)
586 int space
= tty_buffer_request_room(tty
, size
);
588 struct tty_buffer
*tb
= tty
->buf
.tail
;
589 *chars
= tb
->char_buf_ptr
+ tb
->used
;
590 *flags
= tb
->flag_buf_ptr
+ tb
->used
;
596 EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags
);
601 * tty_set_termios_ldisc - set ldisc field
602 * @tty: tty structure
603 * @num: line discipline number
605 * This is probably overkill for real world processors but
606 * they are not on hot paths so a little discipline won't do
609 * Locking: takes termios_mutex
612 static void tty_set_termios_ldisc(struct tty_struct
*tty
, int num
)
614 mutex_lock(&tty
->termios_mutex
);
615 tty
->termios
->c_line
= num
;
616 mutex_unlock(&tty
->termios_mutex
);
620 * This guards the refcounted line discipline lists. The lock
621 * must be taken with irqs off because there are hangup path
622 * callers who will do ldisc lookups and cannot sleep.
625 static DEFINE_SPINLOCK(tty_ldisc_lock
);
626 static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait
);
627 static struct tty_ldisc tty_ldiscs
[NR_LDISCS
]; /* line disc dispatch table */
630 * tty_register_ldisc - install a line discipline
631 * @disc: ldisc number
632 * @new_ldisc: pointer to the ldisc object
634 * Installs a new line discipline into the kernel. The discipline
635 * is set up as unreferenced and then made available to the kernel
636 * from this point onwards.
639 * takes tty_ldisc_lock to guard against ldisc races
642 int tty_register_ldisc(int disc
, struct tty_ldisc
*new_ldisc
)
647 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
650 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
651 tty_ldiscs
[disc
] = *new_ldisc
;
652 tty_ldiscs
[disc
].num
= disc
;
653 tty_ldiscs
[disc
].flags
|= LDISC_FLAG_DEFINED
;
654 tty_ldiscs
[disc
].refcount
= 0;
655 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
659 EXPORT_SYMBOL(tty_register_ldisc
);
662 * tty_unregister_ldisc - unload a line discipline
663 * @disc: ldisc number
664 * @new_ldisc: pointer to the ldisc object
666 * Remove a line discipline from the kernel providing it is not
670 * takes tty_ldisc_lock to guard against ldisc races
673 int tty_unregister_ldisc(int disc
)
678 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
681 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
682 if (tty_ldiscs
[disc
].refcount
)
685 tty_ldiscs
[disc
].flags
&= ~LDISC_FLAG_DEFINED
;
686 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
690 EXPORT_SYMBOL(tty_unregister_ldisc
);
693 * tty_ldisc_get - take a reference to an ldisc
694 * @disc: ldisc number
696 * Takes a reference to a line discipline. Deals with refcounts and
697 * module locking counts. Returns NULL if the discipline is not available.
698 * Returns a pointer to the discipline and bumps the ref count if it is
702 * takes tty_ldisc_lock to guard against ldisc races
705 struct tty_ldisc
*tty_ldisc_get(int disc
)
708 struct tty_ldisc
*ld
;
710 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
713 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
715 ld
= &tty_ldiscs
[disc
];
716 /* Check the entry is defined */
717 if(ld
->flags
& LDISC_FLAG_DEFINED
)
719 /* If the module is being unloaded we can't use it */
720 if (!try_module_get(ld
->owner
))
727 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
731 EXPORT_SYMBOL_GPL(tty_ldisc_get
);
734 * tty_ldisc_put - drop ldisc reference
735 * @disc: ldisc number
737 * Drop a reference to a line discipline. Manage refcounts and
738 * module usage counts
741 * takes tty_ldisc_lock to guard against ldisc races
744 void tty_ldisc_put(int disc
)
746 struct tty_ldisc
*ld
;
749 BUG_ON(disc
< N_TTY
|| disc
>= NR_LDISCS
);
751 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
752 ld
= &tty_ldiscs
[disc
];
753 BUG_ON(ld
->refcount
== 0);
755 module_put(ld
->owner
);
756 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
759 EXPORT_SYMBOL_GPL(tty_ldisc_put
);
762 * tty_ldisc_assign - set ldisc on a tty
763 * @tty: tty to assign
764 * @ld: line discipline
766 * Install an instance of a line discipline into a tty structure. The
767 * ldisc must have a reference count above zero to ensure it remains/
768 * The tty instance refcount starts at zero.
771 * Caller must hold references
774 static void tty_ldisc_assign(struct tty_struct
*tty
, struct tty_ldisc
*ld
)
777 tty
->ldisc
.refcount
= 0;
781 * tty_ldisc_try - internal helper
784 * Make a single attempt to grab and bump the refcount on
785 * the tty ldisc. Return 0 on failure or 1 on success. This is
786 * used to implement both the waiting and non waiting versions
789 * Locking: takes tty_ldisc_lock
792 static int tty_ldisc_try(struct tty_struct
*tty
)
795 struct tty_ldisc
*ld
;
798 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
800 if(test_bit(TTY_LDISC
, &tty
->flags
))
805 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
810 * tty_ldisc_ref_wait - wait for the tty ldisc
813 * Dereference the line discipline for the terminal and take a
814 * reference to it. If the line discipline is in flux then
815 * wait patiently until it changes.
817 * Note: Must not be called from an IRQ/timer context. The caller
818 * must also be careful not to hold other locks that will deadlock
819 * against a discipline change, such as an existing ldisc reference
820 * (which we check for)
822 * Locking: call functions take tty_ldisc_lock
825 struct tty_ldisc
*tty_ldisc_ref_wait(struct tty_struct
*tty
)
827 /* wait_event is a macro */
828 wait_event(tty_ldisc_wait
, tty_ldisc_try(tty
));
829 if(tty
->ldisc
.refcount
== 0)
830 printk(KERN_ERR
"tty_ldisc_ref_wait\n");
834 EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait
);
837 * tty_ldisc_ref - get the tty ldisc
840 * Dereference the line discipline for the terminal and take a
841 * reference to it. If the line discipline is in flux then
842 * return NULL. Can be called from IRQ and timer functions.
844 * Locking: called functions take tty_ldisc_lock
847 struct tty_ldisc
*tty_ldisc_ref(struct tty_struct
*tty
)
849 if(tty_ldisc_try(tty
))
854 EXPORT_SYMBOL_GPL(tty_ldisc_ref
);
857 * tty_ldisc_deref - free a tty ldisc reference
858 * @ld: reference to free up
860 * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
861 * be called in IRQ context.
863 * Locking: takes tty_ldisc_lock
866 void tty_ldisc_deref(struct tty_ldisc
*ld
)
872 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
873 if(ld
->refcount
== 0)
874 printk(KERN_ERR
"tty_ldisc_deref: no references.\n");
877 if(ld
->refcount
== 0)
878 wake_up(&tty_ldisc_wait
);
879 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
882 EXPORT_SYMBOL_GPL(tty_ldisc_deref
);
885 * tty_ldisc_enable - allow ldisc use
886 * @tty: terminal to activate ldisc on
888 * Set the TTY_LDISC flag when the line discipline can be called
889 * again. Do neccessary wakeups for existing sleepers.
891 * Note: nobody should set this bit except via this function. Clearing
892 * directly is allowed.
895 static void tty_ldisc_enable(struct tty_struct
*tty
)
897 set_bit(TTY_LDISC
, &tty
->flags
);
898 wake_up(&tty_ldisc_wait
);
902 * tty_set_ldisc - set line discipline
903 * @tty: the terminal to set
904 * @ldisc: the line discipline
906 * Set the discipline of a tty line. Must be called from a process
909 * Locking: takes tty_ldisc_lock.
910 * called functions take termios_mutex
913 static int tty_set_ldisc(struct tty_struct
*tty
, int ldisc
)
916 struct tty_ldisc o_ldisc
;
920 struct tty_ldisc
*ld
;
921 struct tty_struct
*o_tty
;
923 if ((ldisc
< N_TTY
) || (ldisc
>= NR_LDISCS
))
928 ld
= tty_ldisc_get(ldisc
);
929 /* Eduardo Blanco <ejbs@cs.cs.com.uy> */
930 /* Cyrus Durgin <cider@speakeasy.org> */
932 request_module("tty-ldisc-%d", ldisc
);
933 ld
= tty_ldisc_get(ldisc
);
939 * No more input please, we are switching. The new ldisc
940 * will update this value in the ldisc open function
943 tty
->receive_room
= 0;
946 * Problem: What do we do if this blocks ?
949 tty_wait_until_sent(tty
, 0);
951 if (tty
->ldisc
.num
== ldisc
) {
952 tty_ldisc_put(ldisc
);
956 o_ldisc
= tty
->ldisc
;
960 * Make sure we don't change while someone holds a
961 * reference to the line discipline. The TTY_LDISC bit
962 * prevents anyone taking a reference once it is clear.
963 * We need the lock to avoid racing reference takers.
966 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
967 if (tty
->ldisc
.refcount
|| (o_tty
&& o_tty
->ldisc
.refcount
)) {
968 if(tty
->ldisc
.refcount
) {
969 /* Free the new ldisc we grabbed. Must drop the lock
971 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
972 tty_ldisc_put(ldisc
);
974 * There are several reasons we may be busy, including
975 * random momentary I/O traffic. We must therefore
976 * retry. We could distinguish between blocking ops
977 * and retries if we made tty_ldisc_wait() smarter. That
978 * is up for discussion.
980 if (wait_event_interruptible(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0) < 0)
984 if(o_tty
&& o_tty
->ldisc
.refcount
) {
985 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
986 tty_ldisc_put(ldisc
);
987 if (wait_event_interruptible(tty_ldisc_wait
, o_tty
->ldisc
.refcount
== 0) < 0)
993 /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */
995 if (!test_bit(TTY_LDISC
, &tty
->flags
)) {
996 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
997 tty_ldisc_put(ldisc
);
998 ld
= tty_ldisc_ref_wait(tty
);
1003 clear_bit(TTY_LDISC
, &tty
->flags
);
1005 clear_bit(TTY_LDISC
, &o_tty
->flags
);
1006 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1009 * From this point on we know nobody has an ldisc
1010 * usage reference, nor can they obtain one until
1011 * we say so later on.
1014 work
= cancel_delayed_work(&tty
->buf
.work
);
1016 * Wait for ->hangup_work and ->buf.work handlers to terminate
1019 flush_scheduled_work();
1020 /* Shutdown the current discipline. */
1021 if (tty
->ldisc
.close
)
1022 (tty
->ldisc
.close
)(tty
);
1024 /* Now set up the new line discipline. */
1025 tty_ldisc_assign(tty
, ld
);
1026 tty_set_termios_ldisc(tty
, ldisc
);
1027 if (tty
->ldisc
.open
)
1028 retval
= (tty
->ldisc
.open
)(tty
);
1030 tty_ldisc_put(ldisc
);
1031 /* There is an outstanding reference here so this is safe */
1032 tty_ldisc_assign(tty
, tty_ldisc_get(o_ldisc
.num
));
1033 tty_set_termios_ldisc(tty
, tty
->ldisc
.num
);
1034 if (tty
->ldisc
.open
&& (tty
->ldisc
.open(tty
) < 0)) {
1035 tty_ldisc_put(o_ldisc
.num
);
1036 /* This driver is always present */
1037 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
1038 tty_set_termios_ldisc(tty
, N_TTY
);
1039 if (tty
->ldisc
.open
) {
1040 int r
= tty
->ldisc
.open(tty
);
1043 panic("Couldn't open N_TTY ldisc for "
1045 tty_name(tty
, buf
), r
);
1049 /* At this point we hold a reference to the new ldisc and a
1050 a reference to the old ldisc. If we ended up flipping back
1051 to the existing ldisc we have two references to it */
1053 if (tty
->ldisc
.num
!= o_ldisc
.num
&& tty
->driver
->set_ldisc
)
1054 tty
->driver
->set_ldisc(tty
);
1056 tty_ldisc_put(o_ldisc
.num
);
1059 * Allow ldisc referencing to occur as soon as the driver
1060 * ldisc callback completes.
1063 tty_ldisc_enable(tty
);
1065 tty_ldisc_enable(o_tty
);
1067 /* Restart it in case no characters kick it off. Safe if
1070 schedule_delayed_work(&tty
->buf
.work
, 1);
1075 * get_tty_driver - find device of a tty
1076 * @dev_t: device identifier
1077 * @index: returns the index of the tty
1079 * This routine returns a tty driver structure, given a device number
1080 * and also passes back the index number.
1082 * Locking: caller must hold tty_mutex
1085 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
1087 struct tty_driver
*p
;
1089 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
1090 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
1091 if (device
< base
|| device
>= base
+ p
->num
)
1093 *index
= device
- base
;
1100 * tty_check_change - check for POSIX terminal changes
1101 * @tty: tty to check
1103 * If we try to write to, or set the state of, a terminal and we're
1104 * not in the foreground, send a SIGTTOU. If the signal is blocked or
1105 * ignored, go ahead and perform the operation. (POSIX 7.2)
1110 int tty_check_change(struct tty_struct
* tty
)
1112 if (current
->signal
->tty
!= tty
)
1115 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
1118 if (task_pgrp(current
) == tty
->pgrp
)
1120 if (is_ignored(SIGTTOU
))
1122 if (is_current_pgrp_orphaned())
1124 (void) kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
1125 return -ERESTARTSYS
;
1128 EXPORT_SYMBOL(tty_check_change
);
1130 static ssize_t
hung_up_tty_read(struct file
* file
, char __user
* buf
,
1131 size_t count
, loff_t
*ppos
)
1136 static ssize_t
hung_up_tty_write(struct file
* file
, const char __user
* buf
,
1137 size_t count
, loff_t
*ppos
)
1142 /* No kernel lock held - none needed ;) */
1143 static unsigned int hung_up_tty_poll(struct file
* filp
, poll_table
* wait
)
1145 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
1148 static int hung_up_tty_ioctl(struct inode
* inode
, struct file
* file
,
1149 unsigned int cmd
, unsigned long arg
)
1151 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
1154 static const struct file_operations tty_fops
= {
1155 .llseek
= no_llseek
,
1161 .release
= tty_release
,
1162 .fasync
= tty_fasync
,
1165 #ifdef CONFIG_UNIX98_PTYS
1166 static const struct file_operations ptmx_fops
= {
1167 .llseek
= no_llseek
,
1173 .release
= tty_release
,
1174 .fasync
= tty_fasync
,
1178 static const struct file_operations console_fops
= {
1179 .llseek
= no_llseek
,
1181 .write
= redirected_tty_write
,
1185 .release
= tty_release
,
1186 .fasync
= tty_fasync
,
1189 static const struct file_operations hung_up_tty_fops
= {
1190 .llseek
= no_llseek
,
1191 .read
= hung_up_tty_read
,
1192 .write
= hung_up_tty_write
,
1193 .poll
= hung_up_tty_poll
,
1194 .ioctl
= hung_up_tty_ioctl
,
1195 .release
= tty_release
,
1198 static DEFINE_SPINLOCK(redirect_lock
);
1199 static struct file
*redirect
;
1202 * tty_wakeup - request more data
1205 * Internal and external helper for wakeups of tty. This function
1206 * informs the line discipline if present that the driver is ready
1207 * to receive more output data.
1210 void tty_wakeup(struct tty_struct
*tty
)
1212 struct tty_ldisc
*ld
;
1214 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
1215 ld
= tty_ldisc_ref(tty
);
1217 if(ld
->write_wakeup
)
1218 ld
->write_wakeup(tty
);
1219 tty_ldisc_deref(ld
);
1222 wake_up_interruptible(&tty
->write_wait
);
1225 EXPORT_SYMBOL_GPL(tty_wakeup
);
1228 * tty_ldisc_flush - flush line discipline queue
1231 * Flush the line discipline queue (if any) for this tty. If there
1232 * is no line discipline active this is a no-op.
1235 void tty_ldisc_flush(struct tty_struct
*tty
)
1237 struct tty_ldisc
*ld
= tty_ldisc_ref(tty
);
1239 if(ld
->flush_buffer
)
1240 ld
->flush_buffer(tty
);
1241 tty_ldisc_deref(ld
);
1245 EXPORT_SYMBOL_GPL(tty_ldisc_flush
);
1248 * tty_reset_termios - reset terminal state
1249 * @tty: tty to reset
1251 * Restore a terminal to the driver default state
1254 static void tty_reset_termios(struct tty_struct
*tty
)
1256 mutex_lock(&tty
->termios_mutex
);
1257 *tty
->termios
= tty
->driver
->init_termios
;
1258 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1259 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1260 mutex_unlock(&tty
->termios_mutex
);
1264 * do_tty_hangup - actual handler for hangup events
1267 * This can be called by the "eventd" kernel thread. That is process
1268 * synchronous but doesn't hold any locks, so we need to make sure we
1269 * have the appropriate locks for what we're doing.
1271 * The hangup event clears any pending redirections onto the hung up
1272 * device. It ensures future writes will error and it does the needed
1273 * line discipline hangup and signal delivery. The tty object itself
1278 * redirect lock for undoing redirection
1279 * file list lock for manipulating list of ttys
1280 * tty_ldisc_lock from called functions
1281 * termios_mutex resetting termios data
1282 * tasklist_lock to walk task list for hangup event
1283 * ->siglock to protect ->signal/->sighand
1285 static void do_tty_hangup(struct work_struct
*work
)
1287 struct tty_struct
*tty
=
1288 container_of(work
, struct tty_struct
, hangup_work
);
1289 struct file
* cons_filp
= NULL
;
1290 struct file
*filp
, *f
= NULL
;
1291 struct task_struct
*p
;
1292 struct tty_ldisc
*ld
;
1293 int closecount
= 0, n
;
1298 /* inuse_filps is protected by the single kernel lock */
1301 spin_lock(&redirect_lock
);
1302 if (redirect
&& redirect
->private_data
== tty
) {
1306 spin_unlock(&redirect_lock
);
1308 check_tty_count(tty
, "do_tty_hangup");
1310 /* This breaks for file handles being sent over AF_UNIX sockets ? */
1311 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
1312 if (filp
->f_op
->write
== redirected_tty_write
)
1314 if (filp
->f_op
->write
!= tty_write
)
1317 tty_fasync(-1, filp
, 0); /* can't block */
1318 filp
->f_op
= &hung_up_tty_fops
;
1322 /* FIXME! What are the locking issues here? This may me overdoing things..
1323 * this question is especially important now that we've removed the irqlock. */
1325 ld
= tty_ldisc_ref(tty
);
1326 if(ld
!= NULL
) /* We may have no line discipline at this point */
1328 if (ld
->flush_buffer
)
1329 ld
->flush_buffer(tty
);
1330 if (tty
->driver
->flush_buffer
)
1331 tty
->driver
->flush_buffer(tty
);
1332 if ((test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) &&
1334 ld
->write_wakeup(tty
);
1339 /* FIXME: Once we trust the LDISC code better we can wait here for
1340 ldisc completion and fix the driver call race */
1342 wake_up_interruptible(&tty
->write_wait
);
1343 wake_up_interruptible(&tty
->read_wait
);
1346 * Shutdown the current line discipline, and reset it to
1349 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1350 tty_reset_termios(tty
);
1352 /* Defer ldisc switch */
1353 /* tty_deferred_ldisc_switch(N_TTY);
1355 This should get done automatically when the port closes and
1356 tty_release is called */
1358 read_lock(&tasklist_lock
);
1360 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
1361 spin_lock_irq(&p
->sighand
->siglock
);
1362 if (p
->signal
->tty
== tty
)
1363 p
->signal
->tty
= NULL
;
1364 if (!p
->signal
->leader
) {
1365 spin_unlock_irq(&p
->sighand
->siglock
);
1368 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
1369 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
1370 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
1372 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
1373 spin_unlock_irq(&p
->sighand
->siglock
);
1374 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
1376 read_unlock(&tasklist_lock
);
1379 tty
->session
= NULL
;
1381 tty
->ctrl_status
= 0;
1383 * If one of the devices matches a console pointer, we
1384 * cannot just call hangup() because that will cause
1385 * tty->count and state->count to go out of sync.
1386 * So we just call close() the right number of times.
1389 if (tty
->driver
->close
)
1390 for (n
= 0; n
< closecount
; n
++)
1391 tty
->driver
->close(tty
, cons_filp
);
1392 } else if (tty
->driver
->hangup
)
1393 (tty
->driver
->hangup
)(tty
);
1395 /* We don't want to have driver/ldisc interactions beyond
1396 the ones we did here. The driver layer expects no
1397 calls after ->hangup() from the ldisc side. However we
1398 can't yet guarantee all that */
1400 set_bit(TTY_HUPPED
, &tty
->flags
);
1402 tty_ldisc_enable(tty
);
1403 tty_ldisc_deref(ld
);
1411 * tty_hangup - trigger a hangup event
1412 * @tty: tty to hangup
1414 * A carrier loss (virtual or otherwise) has occurred on this like
1415 * schedule a hangup sequence to run after this event.
1418 void tty_hangup(struct tty_struct
* tty
)
1420 #ifdef TTY_DEBUG_HANGUP
1423 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
1425 schedule_work(&tty
->hangup_work
);
1428 EXPORT_SYMBOL(tty_hangup
);
1431 * tty_vhangup - process vhangup
1432 * @tty: tty to hangup
1434 * The user has asked via system call for the terminal to be hung up.
1435 * We do this synchronously so that when the syscall returns the process
1436 * is complete. That guarantee is neccessary for security reasons.
1439 void tty_vhangup(struct tty_struct
* tty
)
1441 #ifdef TTY_DEBUG_HANGUP
1444 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
1446 do_tty_hangup(&tty
->hangup_work
);
1448 EXPORT_SYMBOL(tty_vhangup
);
1451 * tty_hung_up_p - was tty hung up
1452 * @filp: file pointer of tty
1454 * Return true if the tty has been subject to a vhangup or a carrier
1458 int tty_hung_up_p(struct file
* filp
)
1460 return (filp
->f_op
== &hung_up_tty_fops
);
1463 EXPORT_SYMBOL(tty_hung_up_p
);
1465 static void session_clear_tty(struct pid
*session
)
1467 struct task_struct
*p
;
1468 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
1470 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
1474 * disassociate_ctty - disconnect controlling tty
1475 * @on_exit: true if exiting so need to "hang up" the session
1477 * This function is typically called only by the session leader, when
1478 * it wants to disassociate itself from its controlling tty.
1480 * It performs the following functions:
1481 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
1482 * (2) Clears the tty from being controlling the session
1483 * (3) Clears the controlling tty for all processes in the
1486 * The argument on_exit is set to 1 if called when a process is
1487 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
1490 * BKL is taken for hysterical raisins
1491 * tty_mutex is taken to protect tty
1492 * ->siglock is taken to protect ->signal/->sighand
1493 * tasklist_lock is taken to walk process list for sessions
1494 * ->siglock is taken to protect ->signal/->sighand
1497 void disassociate_ctty(int on_exit
)
1499 struct tty_struct
*tty
;
1500 struct pid
*tty_pgrp
= NULL
;
1504 mutex_lock(&tty_mutex
);
1505 tty
= get_current_tty();
1507 tty_pgrp
= get_pid(tty
->pgrp
);
1508 mutex_unlock(&tty_mutex
);
1509 /* XXX: here we race, there is nothing protecting tty */
1510 if (on_exit
&& tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
1512 } else if (on_exit
) {
1513 struct pid
*old_pgrp
;
1514 spin_lock_irq(¤t
->sighand
->siglock
);
1515 old_pgrp
= current
->signal
->tty_old_pgrp
;
1516 current
->signal
->tty_old_pgrp
= NULL
;
1517 spin_unlock_irq(¤t
->sighand
->siglock
);
1519 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
1520 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
1523 mutex_unlock(&tty_mutex
);
1528 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
1530 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
1534 spin_lock_irq(¤t
->sighand
->siglock
);
1535 tty_pgrp
= current
->signal
->tty_old_pgrp
;
1536 current
->signal
->tty_old_pgrp
= 0;
1537 spin_unlock_irq(¤t
->sighand
->siglock
);
1540 mutex_lock(&tty_mutex
);
1541 /* It is possible that do_tty_hangup has free'd this tty */
1542 tty
= get_current_tty();
1544 put_pid(tty
->session
);
1546 tty
->session
= NULL
;
1549 #ifdef TTY_DEBUG_HANGUP
1550 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
1554 mutex_unlock(&tty_mutex
);
1556 /* Now clear signal->tty under the lock */
1557 read_lock(&tasklist_lock
);
1558 session_clear_tty(task_session(current
));
1559 read_unlock(&tasklist_lock
);
1565 * stop_tty - propogate flow control
1568 * Perform flow control to the driver. For PTY/TTY pairs we
1569 * must also propogate the TIOCKPKT status. May be called
1570 * on an already stopped device and will not re-call the driver
1573 * This functionality is used by both the line disciplines for
1574 * halting incoming flow and by the driver. It may therefore be
1575 * called from any context, may be under the tty atomic_write_lock
1579 * Broken. Relies on BKL which is unsafe here.
1582 void stop_tty(struct tty_struct
*tty
)
1587 if (tty
->link
&& tty
->link
->packet
) {
1588 tty
->ctrl_status
&= ~TIOCPKT_START
;
1589 tty
->ctrl_status
|= TIOCPKT_STOP
;
1590 wake_up_interruptible(&tty
->link
->read_wait
);
1592 if (tty
->driver
->stop
)
1593 (tty
->driver
->stop
)(tty
);
1596 EXPORT_SYMBOL(stop_tty
);
1599 * start_tty - propogate flow control
1600 * @tty: tty to start
1602 * Start a tty that has been stopped if at all possible. Perform
1603 * any neccessary wakeups and propogate the TIOCPKT status. If this
1604 * is the tty was previous stopped and is being started then the
1605 * driver start method is invoked and the line discipline woken.
1608 * Broken. Relies on BKL which is unsafe here.
1611 void start_tty(struct tty_struct
*tty
)
1613 if (!tty
->stopped
|| tty
->flow_stopped
)
1616 if (tty
->link
&& tty
->link
->packet
) {
1617 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
1618 tty
->ctrl_status
|= TIOCPKT_START
;
1619 wake_up_interruptible(&tty
->link
->read_wait
);
1621 if (tty
->driver
->start
)
1622 (tty
->driver
->start
)(tty
);
1624 /* If we have a running line discipline it may need kicking */
1628 EXPORT_SYMBOL(start_tty
);
1631 * tty_read - read method for tty device files
1632 * @file: pointer to tty file
1634 * @count: size of user buffer
1637 * Perform the read system call function on this terminal device. Checks
1638 * for hung up devices before calling the line discipline method.
1641 * Locks the line discipline internally while needed
1642 * For historical reasons the line discipline read method is
1643 * invoked under the BKL. This will go away in time so do not rely on it
1644 * in new code. Multiple read calls may be outstanding in parallel.
1647 static ssize_t
tty_read(struct file
* file
, char __user
* buf
, size_t count
,
1651 struct tty_struct
* tty
;
1652 struct inode
*inode
;
1653 struct tty_ldisc
*ld
;
1655 tty
= (struct tty_struct
*)file
->private_data
;
1656 inode
= file
->f_path
.dentry
->d_inode
;
1657 if (tty_paranoia_check(tty
, inode
, "tty_read"))
1659 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1662 /* We want to wait for the line discipline to sort out in this
1664 ld
= tty_ldisc_ref_wait(tty
);
1667 i
= (ld
->read
)(tty
,file
,buf
,count
);
1670 tty_ldisc_deref(ld
);
1673 inode
->i_atime
= current_fs_time(inode
->i_sb
);
1678 * Split writes up in sane blocksizes to avoid
1679 * denial-of-service type attacks
1681 static inline ssize_t
do_tty_write(
1682 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1683 struct tty_struct
*tty
,
1685 const char __user
*buf
,
1688 ssize_t ret
= 0, written
= 0;
1691 /* FIXME: O_NDELAY ... */
1692 if (mutex_lock_interruptible(&tty
->atomic_write_lock
)) {
1693 return -ERESTARTSYS
;
1697 * We chunk up writes into a temporary buffer. This
1698 * simplifies low-level drivers immensely, since they
1699 * don't have locking issues and user mode accesses.
1701 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1704 * The default chunk-size is 2kB, because the NTTY
1705 * layer has problems with bigger chunks. It will
1706 * claim to be able to handle more characters than
1709 * FIXME: This can probably go away now except that 64K chunks
1710 * are too likely to fail unless switched to vmalloc...
1713 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1718 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1719 if (tty
->write_cnt
< chunk
) {
1725 buf
= kmalloc(chunk
, GFP_KERNEL
);
1727 mutex_unlock(&tty
->atomic_write_lock
);
1730 kfree(tty
->write_buf
);
1731 tty
->write_cnt
= chunk
;
1732 tty
->write_buf
= buf
;
1735 /* Do the write .. */
1737 size_t size
= count
;
1741 if (copy_from_user(tty
->write_buf
, buf
, size
))
1744 ret
= write(tty
, file
, tty
->write_buf
, size
);
1754 if (signal_pending(current
))
1759 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1760 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1763 mutex_unlock(&tty
->atomic_write_lock
);
1769 * tty_write - write method for tty device file
1770 * @file: tty file pointer
1771 * @buf: user data to write
1772 * @count: bytes to write
1775 * Write data to a tty device via the line discipline.
1778 * Locks the line discipline as required
1779 * Writes to the tty driver are serialized by the atomic_write_lock
1780 * and are then processed in chunks to the device. The line discipline
1781 * write method will not be involked in parallel for each device
1782 * The line discipline write method is called under the big
1783 * kernel lock for historical reasons. New code should not rely on this.
1786 static ssize_t
tty_write(struct file
* file
, const char __user
* buf
, size_t count
,
1789 struct tty_struct
* tty
;
1790 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1792 struct tty_ldisc
*ld
;
1794 tty
= (struct tty_struct
*)file
->private_data
;
1795 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1797 if (!tty
|| !tty
->driver
->write
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1800 ld
= tty_ldisc_ref_wait(tty
);
1804 ret
= do_tty_write(ld
->write
, tty
, file
, buf
, count
);
1805 tty_ldisc_deref(ld
);
1809 ssize_t
redirected_tty_write(struct file
* file
, const char __user
* buf
, size_t count
,
1812 struct file
*p
= NULL
;
1814 spin_lock(&redirect_lock
);
1819 spin_unlock(&redirect_lock
);
1823 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1828 return tty_write(file
, buf
, count
, ppos
);
1831 static char ptychar
[] = "pqrstuvwxyzabcde";
1834 * pty_line_name - generate name for a pty
1835 * @driver: the tty driver in use
1836 * @index: the minor number
1837 * @p: output buffer of at least 6 bytes
1839 * Generate a name from a driver reference and write it to the output
1844 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1846 int i
= index
+ driver
->name_base
;
1847 /* ->name is initialized to "ttyp", but "tty" is expected */
1848 sprintf(p
, "%s%c%x",
1849 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1850 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1854 * pty_line_name - generate name for a tty
1855 * @driver: the tty driver in use
1856 * @index: the minor number
1857 * @p: output buffer of at least 7 bytes
1859 * Generate a name from a driver reference and write it to the output
1864 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1866 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1870 * init_dev - initialise a tty device
1871 * @driver: tty driver we are opening a device on
1872 * @idx: device index
1873 * @tty: returned tty structure
1875 * Prepare a tty device. This may not be a "new" clean device but
1876 * could also be an active device. The pty drivers require special
1877 * handling because of this.
1880 * The function is called under the tty_mutex, which
1881 * protects us from the tty struct or driver itself going away.
1883 * On exit the tty device has the line discipline attached and
1884 * a reference count of 1. If a pair was created for pty/tty use
1885 * and the other was a pty master then it too has a reference count of 1.
1887 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1888 * failed open. The new code protects the open with a mutex, so it's
1889 * really quite straightforward. The mutex locking can probably be
1890 * relaxed for the (most common) case of reopening a tty.
1893 static int init_dev(struct tty_driver
*driver
, int idx
,
1894 struct tty_struct
**ret_tty
)
1896 struct tty_struct
*tty
, *o_tty
;
1897 struct ktermios
*tp
, **tp_loc
, *o_tp
, **o_tp_loc
;
1898 struct ktermios
*ltp
, **ltp_loc
, *o_ltp
, **o_ltp_loc
;
1901 /* check whether we're reopening an existing tty */
1902 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1903 tty
= devpts_get_tty(idx
);
1904 if (tty
&& driver
->subtype
== PTY_TYPE_MASTER
)
1907 tty
= driver
->ttys
[idx
];
1909 if (tty
) goto fast_track
;
1912 * First time open is complex, especially for PTY devices.
1913 * This code guarantees that either everything succeeds and the
1914 * TTY is ready for operation, or else the table slots are vacated
1915 * and the allocated memory released. (Except that the termios
1916 * and locked termios may be retained.)
1919 if (!try_module_get(driver
->owner
)) {
1928 tty
= alloc_tty_struct();
1931 initialize_tty_struct(tty
);
1932 tty
->driver
= driver
;
1934 tty_line_name(driver
, idx
, tty
->name
);
1936 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1937 tp_loc
= &tty
->termios
;
1938 ltp_loc
= &tty
->termios_locked
;
1940 tp_loc
= &driver
->termios
[idx
];
1941 ltp_loc
= &driver
->termios_locked
[idx
];
1945 tp
= (struct ktermios
*) kmalloc(sizeof(struct ktermios
),
1949 *tp
= driver
->init_termios
;
1953 ltp
= (struct ktermios
*) kmalloc(sizeof(struct ktermios
),
1957 memset(ltp
, 0, sizeof(struct ktermios
));
1960 if (driver
->type
== TTY_DRIVER_TYPE_PTY
) {
1961 o_tty
= alloc_tty_struct();
1964 initialize_tty_struct(o_tty
);
1965 o_tty
->driver
= driver
->other
;
1967 tty_line_name(driver
->other
, idx
, o_tty
->name
);
1969 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1970 o_tp_loc
= &o_tty
->termios
;
1971 o_ltp_loc
= &o_tty
->termios_locked
;
1973 o_tp_loc
= &driver
->other
->termios
[idx
];
1974 o_ltp_loc
= &driver
->other
->termios_locked
[idx
];
1978 o_tp
= (struct ktermios
*)
1979 kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1982 *o_tp
= driver
->other
->init_termios
;
1986 o_ltp
= (struct ktermios
*)
1987 kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
1990 memset(o_ltp
, 0, sizeof(struct ktermios
));
1994 * Everything allocated ... set up the o_tty structure.
1996 if (!(driver
->other
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
1997 driver
->other
->ttys
[idx
] = o_tty
;
2003 o_tty
->termios
= *o_tp_loc
;
2004 o_tty
->termios_locked
= *o_ltp_loc
;
2005 driver
->other
->refcount
++;
2006 if (driver
->subtype
== PTY_TYPE_MASTER
)
2009 /* Establish the links in both directions */
2015 * All structures have been allocated, so now we install them.
2016 * Failures after this point use release_tty to clean up, so
2017 * there's no need to null out the local pointers.
2019 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2020 driver
->ttys
[idx
] = tty
;
2027 tty
->termios
= *tp_loc
;
2028 tty
->termios_locked
= *ltp_loc
;
2029 /* Compatibility until drivers always set this */
2030 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
2031 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
2036 * Structures all installed ... call the ldisc open routines.
2037 * If we fail here just call release_tty to clean up. No need
2038 * to decrement the use counts, as release_tty doesn't care.
2041 if (tty
->ldisc
.open
) {
2042 retval
= (tty
->ldisc
.open
)(tty
);
2044 goto release_mem_out
;
2046 if (o_tty
&& o_tty
->ldisc
.open
) {
2047 retval
= (o_tty
->ldisc
.open
)(o_tty
);
2049 if (tty
->ldisc
.close
)
2050 (tty
->ldisc
.close
)(tty
);
2051 goto release_mem_out
;
2053 tty_ldisc_enable(o_tty
);
2055 tty_ldisc_enable(tty
);
2059 * This fast open can be used if the tty is already open.
2060 * No memory is allocated, and the only failures are from
2061 * attempting to open a closing tty or attempting multiple
2062 * opens on a pty master.
2065 if (test_bit(TTY_CLOSING
, &tty
->flags
)) {
2069 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2070 driver
->subtype
== PTY_TYPE_MASTER
) {
2072 * special case for PTY masters: only one open permitted,
2073 * and the slave side open count is incremented as well.
2082 tty
->driver
= driver
; /* N.B. why do this every time?? */
2085 if(!test_bit(TTY_LDISC
, &tty
->flags
))
2086 printk(KERN_ERR
"init_dev but no ldisc\n");
2090 /* All paths come through here to release the mutex */
2094 /* Release locally allocated memory ... nothing placed in slots */
2098 free_tty_struct(o_tty
);
2101 free_tty_struct(tty
);
2104 module_put(driver
->owner
);
2108 /* call the tty release_tty routine to clean out this slot */
2110 if (printk_ratelimit())
2111 printk(KERN_INFO
"init_dev: ldisc open failed, "
2112 "clearing slot %d\n", idx
);
2113 release_tty(tty
, idx
);
2118 * release_one_tty - release tty structure memory
2120 * Releases memory associated with a tty structure, and clears out the
2121 * driver table slots. This function is called when a device is no longer
2122 * in use. It also gets called when setup of a device fails.
2125 * tty_mutex - sometimes only
2126 * takes the file list lock internally when working on the list
2127 * of ttys that the driver keeps.
2128 * FIXME: should we require tty_mutex is held here ??
2130 static void release_one_tty(struct tty_struct
*tty
, int idx
)
2132 int devpts
= tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
;
2133 struct ktermios
*tp
;
2136 tty
->driver
->ttys
[idx
] = NULL
;
2138 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
2141 tty
->driver
->termios
[idx
] = NULL
;
2144 tp
= tty
->termios_locked
;
2146 tty
->driver
->termios_locked
[idx
] = NULL
;
2152 tty
->driver
->refcount
--;
2155 list_del_init(&tty
->tty_files
);
2158 free_tty_struct(tty
);
2162 * release_tty - release tty structure memory
2164 * Release both @tty and a possible linked partner (think pty pair),
2165 * and decrement the refcount of the backing module.
2168 * tty_mutex - sometimes only
2169 * takes the file list lock internally when working on the list
2170 * of ttys that the driver keeps.
2171 * FIXME: should we require tty_mutex is held here ??
2173 static void release_tty(struct tty_struct
*tty
, int idx
)
2175 struct tty_driver
*driver
= tty
->driver
;
2178 release_one_tty(tty
->link
, idx
);
2179 release_one_tty(tty
, idx
);
2180 module_put(driver
->owner
);
2184 * Even releasing the tty structures is a tricky business.. We have
2185 * to be very careful that the structures are all released at the
2186 * same time, as interrupts might otherwise get the wrong pointers.
2188 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
2189 * lead to double frees or releasing memory still in use.
2191 static void release_dev(struct file
* filp
)
2193 struct tty_struct
*tty
, *o_tty
;
2194 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
2198 unsigned long flags
;
2200 tty
= (struct tty_struct
*)filp
->private_data
;
2201 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "release_dev"))
2204 check_tty_count(tty
, "release_dev");
2206 tty_fasync(-1, filp
, 0);
2209 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2210 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2211 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
2214 #ifdef TTY_PARANOIA_CHECK
2215 if (idx
< 0 || idx
>= tty
->driver
->num
) {
2216 printk(KERN_DEBUG
"release_dev: bad idx when trying to "
2217 "free (%s)\n", tty
->name
);
2220 if (!(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2221 if (tty
!= tty
->driver
->ttys
[idx
]) {
2222 printk(KERN_DEBUG
"release_dev: driver.table[%d] not tty "
2223 "for (%s)\n", idx
, tty
->name
);
2226 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
2227 printk(KERN_DEBUG
"release_dev: driver.termios[%d] not termios "
2232 if (tty
->termios_locked
!= tty
->driver
->termios_locked
[idx
]) {
2233 printk(KERN_DEBUG
"release_dev: driver.termios_locked[%d] not "
2234 "termios_locked for (%s)\n",
2241 #ifdef TTY_DEBUG_HANGUP
2242 printk(KERN_DEBUG
"release_dev of %s (tty count=%d)...",
2243 tty_name(tty
, buf
), tty
->count
);
2246 #ifdef TTY_PARANOIA_CHECK
2247 if (tty
->driver
->other
&&
2248 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2249 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
2250 printk(KERN_DEBUG
"release_dev: other->table[%d] "
2251 "not o_tty for (%s)\n",
2255 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
2256 printk(KERN_DEBUG
"release_dev: other->termios[%d] "
2257 "not o_termios for (%s)\n",
2261 if (o_tty
->termios_locked
!=
2262 tty
->driver
->other
->termios_locked
[idx
]) {
2263 printk(KERN_DEBUG
"release_dev: other->termios_locked["
2264 "%d] not o_termios_locked for (%s)\n",
2268 if (o_tty
->link
!= tty
) {
2269 printk(KERN_DEBUG
"release_dev: bad pty pointers\n");
2274 if (tty
->driver
->close
)
2275 tty
->driver
->close(tty
, filp
);
2278 * Sanity check: if tty->count is going to zero, there shouldn't be
2279 * any waiters on tty->read_wait or tty->write_wait. We test the
2280 * wait queues and kick everyone out _before_ actually starting to
2281 * close. This ensures that we won't block while releasing the tty
2284 * The test for the o_tty closing is necessary, since the master and
2285 * slave sides may close in any order. If the slave side closes out
2286 * first, its count will be one, since the master side holds an open.
2287 * Thus this test wouldn't be triggered at the time the slave closes,
2290 * Note that it's possible for the tty to be opened again while we're
2291 * flushing out waiters. By recalculating the closing flags before
2292 * each iteration we avoid any problems.
2295 /* Guard against races with tty->count changes elsewhere and
2296 opens on /dev/tty */
2298 mutex_lock(&tty_mutex
);
2299 tty_closing
= tty
->count
<= 1;
2300 o_tty_closing
= o_tty
&&
2301 (o_tty
->count
<= (pty_master
? 1 : 0));
2305 if (waitqueue_active(&tty
->read_wait
)) {
2306 wake_up(&tty
->read_wait
);
2309 if (waitqueue_active(&tty
->write_wait
)) {
2310 wake_up(&tty
->write_wait
);
2314 if (o_tty_closing
) {
2315 if (waitqueue_active(&o_tty
->read_wait
)) {
2316 wake_up(&o_tty
->read_wait
);
2319 if (waitqueue_active(&o_tty
->write_wait
)) {
2320 wake_up(&o_tty
->write_wait
);
2327 printk(KERN_WARNING
"release_dev: %s: read/write wait queue "
2328 "active!\n", tty_name(tty
, buf
));
2329 mutex_unlock(&tty_mutex
);
2334 * The closing flags are now consistent with the open counts on
2335 * both sides, and we've completed the last operation that could
2336 * block, so it's safe to proceed with closing.
2339 if (--o_tty
->count
< 0) {
2340 printk(KERN_WARNING
"release_dev: bad pty slave count "
2342 o_tty
->count
, tty_name(o_tty
, buf
));
2346 if (--tty
->count
< 0) {
2347 printk(KERN_WARNING
"release_dev: bad tty->count (%d) for %s\n",
2348 tty
->count
, tty_name(tty
, buf
));
2353 * We've decremented tty->count, so we need to remove this file
2354 * descriptor off the tty->tty_files list; this serves two
2356 * - check_tty_count sees the correct number of file descriptors
2357 * associated with this tty.
2358 * - do_tty_hangup no longer sees this file descriptor as
2359 * something that needs to be handled for hangups.
2362 filp
->private_data
= NULL
;
2365 * Perform some housekeeping before deciding whether to return.
2367 * Set the TTY_CLOSING flag if this was the last open. In the
2368 * case of a pty we may have to wait around for the other side
2369 * to close, and TTY_CLOSING makes sure we can't be reopened.
2372 set_bit(TTY_CLOSING
, &tty
->flags
);
2374 set_bit(TTY_CLOSING
, &o_tty
->flags
);
2377 * If _either_ side is closing, make sure there aren't any
2378 * processes that still think tty or o_tty is their controlling
2381 if (tty_closing
|| o_tty_closing
) {
2382 read_lock(&tasklist_lock
);
2383 session_clear_tty(tty
->session
);
2385 session_clear_tty(o_tty
->session
);
2386 read_unlock(&tasklist_lock
);
2389 mutex_unlock(&tty_mutex
);
2391 /* check whether both sides are closing ... */
2392 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
2395 #ifdef TTY_DEBUG_HANGUP
2396 printk(KERN_DEBUG
"freeing tty structure...");
2399 * Prevent flush_to_ldisc() from rescheduling the work for later. Then
2400 * kill any delayed work. As this is the final close it does not
2401 * race with the set_ldisc code path.
2403 clear_bit(TTY_LDISC
, &tty
->flags
);
2404 cancel_delayed_work(&tty
->buf
.work
);
2407 * Wait for ->hangup_work and ->buf.work handlers to terminate
2410 flush_scheduled_work();
2413 * Wait for any short term users (we know they are just driver
2414 * side waiters as the file is closing so user count on the file
2417 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2418 while(tty
->ldisc
.refcount
)
2420 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2421 wait_event(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0);
2422 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2424 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2426 * Shutdown the current line discipline, and reset it to N_TTY.
2427 * N.B. why reset ldisc when we're releasing the memory??
2429 * FIXME: this MUST get fixed for the new reflocking
2431 if (tty
->ldisc
.close
)
2432 (tty
->ldisc
.close
)(tty
);
2433 tty_ldisc_put(tty
->ldisc
.num
);
2436 * Switch the line discipline back
2438 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
2439 tty_set_termios_ldisc(tty
,N_TTY
);
2441 /* FIXME: could o_tty be in setldisc here ? */
2442 clear_bit(TTY_LDISC
, &o_tty
->flags
);
2443 if (o_tty
->ldisc
.close
)
2444 (o_tty
->ldisc
.close
)(o_tty
);
2445 tty_ldisc_put(o_tty
->ldisc
.num
);
2446 tty_ldisc_assign(o_tty
, tty_ldisc_get(N_TTY
));
2447 tty_set_termios_ldisc(o_tty
,N_TTY
);
2450 * The release_tty function takes care of the details of clearing
2451 * the slots and preserving the termios structure.
2453 release_tty(tty
, idx
);
2455 #ifdef CONFIG_UNIX98_PTYS
2456 /* Make this pty number available for reallocation */
2458 down(&allocated_ptys_lock
);
2459 idr_remove(&allocated_ptys
, idx
);
2460 up(&allocated_ptys_lock
);
2467 * tty_open - open a tty device
2468 * @inode: inode of device file
2469 * @filp: file pointer to tty
2471 * tty_open and tty_release keep up the tty count that contains the
2472 * number of opens done on a tty. We cannot use the inode-count, as
2473 * different inodes might point to the same tty.
2475 * Open-counting is needed for pty masters, as well as for keeping
2476 * track of serial lines: DTR is dropped when the last close happens.
2477 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2479 * The termios state of a pty is reset on first open so that
2480 * settings don't persist across reuse.
2482 * Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
2483 * tty->count should protect the rest.
2484 * ->siglock protects ->signal/->sighand
2487 static int tty_open(struct inode
* inode
, struct file
* filp
)
2489 struct tty_struct
*tty
;
2491 struct tty_driver
*driver
;
2493 dev_t device
= inode
->i_rdev
;
2494 unsigned short saved_flags
= filp
->f_flags
;
2495 struct pid
*old_pgrp
;
2497 nonseekable_open(inode
, filp
);
2500 noctty
= filp
->f_flags
& O_NOCTTY
;
2504 mutex_lock(&tty_mutex
);
2506 if (device
== MKDEV(TTYAUX_MAJOR
,0)) {
2507 tty
= get_current_tty();
2509 mutex_unlock(&tty_mutex
);
2512 driver
= tty
->driver
;
2514 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
2519 if (device
== MKDEV(TTY_MAJOR
,0)) {
2520 extern struct tty_driver
*console_driver
;
2521 driver
= console_driver
;
2527 if (device
== MKDEV(TTYAUX_MAJOR
,1)) {
2528 driver
= console_device(&index
);
2530 /* Don't let /dev/console block */
2531 filp
->f_flags
|= O_NONBLOCK
;
2535 mutex_unlock(&tty_mutex
);
2539 driver
= get_tty_driver(device
, &index
);
2541 mutex_unlock(&tty_mutex
);
2545 retval
= init_dev(driver
, index
, &tty
);
2546 mutex_unlock(&tty_mutex
);
2550 filp
->private_data
= tty
;
2551 file_move(filp
, &tty
->tty_files
);
2552 check_tty_count(tty
, "tty_open");
2553 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2554 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2556 #ifdef TTY_DEBUG_HANGUP
2557 printk(KERN_DEBUG
"opening %s...", tty
->name
);
2560 if (tty
->driver
->open
)
2561 retval
= tty
->driver
->open(tty
, filp
);
2565 filp
->f_flags
= saved_flags
;
2567 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) && !capable(CAP_SYS_ADMIN
))
2571 #ifdef TTY_DEBUG_HANGUP
2572 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
2576 if (retval
!= -ERESTARTSYS
)
2578 if (signal_pending(current
))
2582 * Need to reset f_op in case a hangup happened.
2584 if (filp
->f_op
== &hung_up_tty_fops
)
2585 filp
->f_op
= &tty_fops
;
2590 mutex_lock(&tty_mutex
);
2591 spin_lock_irq(¤t
->sighand
->siglock
);
2593 current
->signal
->leader
&&
2594 !current
->signal
->tty
&&
2595 tty
->session
== NULL
)
2596 old_pgrp
= __proc_set_tty(current
, tty
);
2597 spin_unlock_irq(¤t
->sighand
->siglock
);
2598 mutex_unlock(&tty_mutex
);
2603 #ifdef CONFIG_UNIX98_PTYS
2605 * ptmx_open - open a unix 98 pty master
2606 * @inode: inode of device file
2607 * @filp: file pointer to tty
2609 * Allocate a unix98 pty master device from the ptmx driver.
2611 * Locking: tty_mutex protects theinit_dev work. tty->count should
2613 * allocated_ptys_lock handles the list of free pty numbers
2616 static int ptmx_open(struct inode
* inode
, struct file
* filp
)
2618 struct tty_struct
*tty
;
2623 nonseekable_open(inode
, filp
);
2625 /* find a device that is not in use. */
2626 down(&allocated_ptys_lock
);
2627 if (!idr_pre_get(&allocated_ptys
, GFP_KERNEL
)) {
2628 up(&allocated_ptys_lock
);
2631 idr_ret
= idr_get_new(&allocated_ptys
, NULL
, &index
);
2633 up(&allocated_ptys_lock
);
2634 if (idr_ret
== -EAGAIN
)
2638 if (index
>= pty_limit
) {
2639 idr_remove(&allocated_ptys
, index
);
2640 up(&allocated_ptys_lock
);
2643 up(&allocated_ptys_lock
);
2645 mutex_lock(&tty_mutex
);
2646 retval
= init_dev(ptm_driver
, index
, &tty
);
2647 mutex_unlock(&tty_mutex
);
2652 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
2653 filp
->private_data
= tty
;
2654 file_move(filp
, &tty
->tty_files
);
2657 if (devpts_pty_new(tty
->link
))
2660 check_tty_count(tty
, "tty_open");
2661 retval
= ptm_driver
->open(tty
, filp
);
2668 down(&allocated_ptys_lock
);
2669 idr_remove(&allocated_ptys
, index
);
2670 up(&allocated_ptys_lock
);
2676 * tty_release - vfs callback for close
2677 * @inode: inode of tty
2678 * @filp: file pointer for handle to tty
2680 * Called the last time each file handle is closed that references
2681 * this tty. There may however be several such references.
2684 * Takes bkl. See release_dev
2687 static int tty_release(struct inode
* inode
, struct file
* filp
)
2696 * tty_poll - check tty status
2697 * @filp: file being polled
2698 * @wait: poll wait structures to update
2700 * Call the line discipline polling method to obtain the poll
2701 * status of the device.
2703 * Locking: locks called line discipline but ldisc poll method
2704 * may be re-entered freely by other callers.
2707 static unsigned int tty_poll(struct file
* filp
, poll_table
* wait
)
2709 struct tty_struct
* tty
;
2710 struct tty_ldisc
*ld
;
2713 tty
= (struct tty_struct
*)filp
->private_data
;
2714 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2717 ld
= tty_ldisc_ref_wait(tty
);
2719 ret
= (ld
->poll
)(tty
, filp
, wait
);
2720 tty_ldisc_deref(ld
);
2724 static int tty_fasync(int fd
, struct file
* filp
, int on
)
2726 struct tty_struct
* tty
;
2729 tty
= (struct tty_struct
*)filp
->private_data
;
2730 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2733 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2740 if (!waitqueue_active(&tty
->read_wait
))
2741 tty
->minimum_to_wake
= 1;
2744 type
= PIDTYPE_PGID
;
2746 pid
= task_pid(current
);
2749 retval
= __f_setown(filp
, pid
, type
, 0);
2753 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2754 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2760 * tiocsti - fake input character
2761 * @tty: tty to fake input into
2762 * @p: pointer to character
2764 * Fake input to a tty device. Does the neccessary locking and
2767 * FIXME: does not honour flow control ??
2770 * Called functions take tty_ldisc_lock
2771 * current->signal->tty check is safe without locks
2773 * FIXME: may race normal receive processing
2776 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2779 struct tty_ldisc
*ld
;
2781 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2783 if (get_user(ch
, p
))
2785 ld
= tty_ldisc_ref_wait(tty
);
2786 ld
->receive_buf(tty
, &ch
, &mbz
, 1);
2787 tty_ldisc_deref(ld
);
2792 * tiocgwinsz - implement window query ioctl
2794 * @arg: user buffer for result
2796 * Copies the kernel idea of the window size into the user buffer.
2798 * Locking: tty->termios_mutex is taken to ensure the winsize data
2802 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
* arg
)
2806 mutex_lock(&tty
->termios_mutex
);
2807 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2808 mutex_unlock(&tty
->termios_mutex
);
2810 return err
? -EFAULT
: 0;
2814 * tiocswinsz - implement window size set ioctl
2816 * @arg: user buffer for result
2818 * Copies the user idea of the window size to the kernel. Traditionally
2819 * this is just advisory information but for the Linux console it
2820 * actually has driver level meaning and triggers a VC resize.
2823 * Called function use the console_sem is used to ensure we do
2824 * not try and resize the console twice at once.
2825 * The tty->termios_mutex is used to ensure we don't double
2826 * resize and get confused. Lock order - tty->termios_mutex before
2830 static int tiocswinsz(struct tty_struct
*tty
, struct tty_struct
*real_tty
,
2831 struct winsize __user
* arg
)
2833 struct winsize tmp_ws
;
2835 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2838 mutex_lock(&tty
->termios_mutex
);
2839 if (!memcmp(&tmp_ws
, &tty
->winsize
, sizeof(*arg
)))
2843 if (tty
->driver
->type
== TTY_DRIVER_TYPE_CONSOLE
) {
2844 if (vc_lock_resize(tty
->driver_data
, tmp_ws
.ws_col
,
2846 mutex_unlock(&tty
->termios_mutex
);
2852 kill_pgrp(tty
->pgrp
, SIGWINCH
, 1);
2853 if ((real_tty
->pgrp
!= tty
->pgrp
) && real_tty
->pgrp
)
2854 kill_pgrp(real_tty
->pgrp
, SIGWINCH
, 1);
2855 tty
->winsize
= tmp_ws
;
2856 real_tty
->winsize
= tmp_ws
;
2858 mutex_unlock(&tty
->termios_mutex
);
2863 * tioccons - allow admin to move logical console
2864 * @file: the file to become console
2866 * Allow the adminstrator to move the redirected console device
2868 * Locking: uses redirect_lock to guard the redirect information
2871 static int tioccons(struct file
*file
)
2873 if (!capable(CAP_SYS_ADMIN
))
2875 if (file
->f_op
->write
== redirected_tty_write
) {
2877 spin_lock(&redirect_lock
);
2880 spin_unlock(&redirect_lock
);
2885 spin_lock(&redirect_lock
);
2887 spin_unlock(&redirect_lock
);
2892 spin_unlock(&redirect_lock
);
2897 * fionbio - non blocking ioctl
2898 * @file: file to set blocking value
2899 * @p: user parameter
2901 * Historical tty interfaces had a blocking control ioctl before
2902 * the generic functionality existed. This piece of history is preserved
2903 * in the expected tty API of posix OS's.
2905 * Locking: none, the open fle handle ensures it won't go away.
2908 static int fionbio(struct file
*file
, int __user
*p
)
2912 if (get_user(nonblock
, p
))
2916 file
->f_flags
|= O_NONBLOCK
;
2918 file
->f_flags
&= ~O_NONBLOCK
;
2923 * tiocsctty - set controlling tty
2924 * @tty: tty structure
2925 * @arg: user argument
2927 * This ioctl is used to manage job control. It permits a session
2928 * leader to set this tty as the controlling tty for the session.
2931 * Takes tty_mutex() to protect tty instance
2932 * Takes tasklist_lock internally to walk sessions
2933 * Takes ->siglock() when updating signal->tty
2936 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2939 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2942 mutex_lock(&tty_mutex
);
2944 * The process must be a session leader and
2945 * not have a controlling tty already.
2947 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2954 * This tty is already the controlling
2955 * tty for another session group!
2957 if ((arg
== 1) && capable(CAP_SYS_ADMIN
)) {
2961 read_lock(&tasklist_lock
);
2962 session_clear_tty(tty
->session
);
2963 read_unlock(&tasklist_lock
);
2969 proc_set_tty(current
, tty
);
2971 mutex_unlock(&tty_mutex
);
2976 * tiocgpgrp - get process group
2977 * @tty: tty passed by user
2978 * @real_tty: tty side of the tty pased by the user if a pty else the tty
2981 * Obtain the process group of the tty. If there is no process group
2984 * Locking: none. Reference to current->signal->tty is safe.
2987 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2990 * (tty == real_tty) is a cheap way of
2991 * testing if the tty is NOT a master pty.
2993 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2995 return put_user(pid_nr(real_tty
->pgrp
), p
);
2999 * tiocspgrp - attempt to set process group
3000 * @tty: tty passed by user
3001 * @real_tty: tty side device matching tty passed by user
3004 * Set the process group of the tty to the session passed. Only
3005 * permitted where the tty session is our session.
3010 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3014 int retval
= tty_check_change(real_tty
);
3020 if (!current
->signal
->tty
||
3021 (current
->signal
->tty
!= real_tty
) ||
3022 (real_tty
->session
!= task_session(current
)))
3024 if (get_user(pgrp_nr
, p
))
3029 pgrp
= find_pid(pgrp_nr
);
3034 if (session_of_pgrp(pgrp
) != task_session(current
))
3037 put_pid(real_tty
->pgrp
);
3038 real_tty
->pgrp
= get_pid(pgrp
);
3045 * tiocgsid - get session id
3046 * @tty: tty passed by user
3047 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3048 * @p: pointer to returned session id
3050 * Obtain the session id of the tty. If there is no session
3053 * Locking: none. Reference to current->signal->tty is safe.
3056 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3059 * (tty == real_tty) is a cheap way of
3060 * testing if the tty is NOT a master pty.
3062 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3064 if (!real_tty
->session
)
3066 return put_user(pid_nr(real_tty
->session
), p
);
3070 * tiocsetd - set line discipline
3072 * @p: pointer to user data
3074 * Set the line discipline according to user request.
3076 * Locking: see tty_set_ldisc, this function is just a helper
3079 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
3083 if (get_user(ldisc
, p
))
3085 return tty_set_ldisc(tty
, ldisc
);
3089 * send_break - performed time break
3090 * @tty: device to break on
3091 * @duration: timeout in mS
3093 * Perform a timed break on hardware that lacks its own driver level
3094 * timed break functionality.
3097 * atomic_write_lock serializes
3101 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
3103 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
3105 tty
->driver
->break_ctl(tty
, -1);
3106 if (!signal_pending(current
)) {
3107 msleep_interruptible(duration
);
3109 tty
->driver
->break_ctl(tty
, 0);
3110 mutex_unlock(&tty
->atomic_write_lock
);
3111 if (signal_pending(current
))
3117 * tiocmget - get modem status
3119 * @file: user file pointer
3120 * @p: pointer to result
3122 * Obtain the modem status bits from the tty driver if the feature
3123 * is supported. Return -EINVAL if it is not available.
3125 * Locking: none (up to the driver)
3128 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
3130 int retval
= -EINVAL
;
3132 if (tty
->driver
->tiocmget
) {
3133 retval
= tty
->driver
->tiocmget(tty
, file
);
3136 retval
= put_user(retval
, p
);
3142 * tiocmset - set modem status
3144 * @file: user file pointer
3145 * @cmd: command - clear bits, set bits or set all
3146 * @p: pointer to desired bits
3148 * Set the modem status bits from the tty driver if the feature
3149 * is supported. Return -EINVAL if it is not available.
3151 * Locking: none (up to the driver)
3154 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
3157 int retval
= -EINVAL
;
3159 if (tty
->driver
->tiocmset
) {
3160 unsigned int set
, clear
, val
;
3162 retval
= get_user(val
, p
);
3180 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3181 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3183 retval
= tty
->driver
->tiocmset(tty
, file
, set
, clear
);
3189 * Split this up, as gcc can choke on it otherwise..
3191 int tty_ioctl(struct inode
* inode
, struct file
* file
,
3192 unsigned int cmd
, unsigned long arg
)
3194 struct tty_struct
*tty
, *real_tty
;
3195 void __user
*p
= (void __user
*)arg
;
3197 struct tty_ldisc
*ld
;
3199 tty
= (struct tty_struct
*)file
->private_data
;
3200 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3203 /* CHECKME: is this safe as one end closes ? */
3206 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
3207 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
3208 real_tty
= tty
->link
;
3211 * Break handling by driver
3213 if (!tty
->driver
->break_ctl
) {
3217 if (tty
->driver
->ioctl
)
3218 return tty
->driver
->ioctl(tty
, file
, cmd
, arg
);
3221 /* These two ioctl's always return success; even if */
3222 /* the driver doesn't support them. */
3225 if (!tty
->driver
->ioctl
)
3227 retval
= tty
->driver
->ioctl(tty
, file
, cmd
, arg
);
3228 if (retval
== -ENOIOCTLCMD
)
3235 * Factor out some common prep work
3243 retval
= tty_check_change(tty
);
3246 if (cmd
!= TIOCCBRK
) {
3247 tty_wait_until_sent(tty
, 0);
3248 if (signal_pending(current
))
3256 return tiocsti(tty
, p
);
3258 return tiocgwinsz(tty
, p
);
3260 return tiocswinsz(tty
, real_tty
, p
);
3262 return real_tty
!=tty
? -EINVAL
: tioccons(file
);
3264 return fionbio(file
, p
);
3266 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3269 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3272 if (current
->signal
->tty
!= tty
)
3274 if (current
->signal
->leader
)
3275 disassociate_ctty(0);
3276 proc_clear_tty(current
);
3279 return tiocsctty(tty
, arg
);
3281 return tiocgpgrp(tty
, real_tty
, p
);
3283 return tiocspgrp(tty
, real_tty
, p
);
3285 return tiocgsid(tty
, real_tty
, p
);
3287 /* FIXME: check this is ok */
3288 return put_user(tty
->ldisc
.num
, (int __user
*)p
);
3290 return tiocsetd(tty
, p
);
3293 return tioclinux(tty
, arg
);
3298 case TIOCSBRK
: /* Turn break on, unconditionally */
3299 tty
->driver
->break_ctl(tty
, -1);
3302 case TIOCCBRK
: /* Turn break off, unconditionally */
3303 tty
->driver
->break_ctl(tty
, 0);
3305 case TCSBRK
: /* SVID version: non-zero arg --> no break */
3306 /* non-zero arg means wait for all output data
3307 * to be sent (performed above) but don't send break.
3308 * This is used by the tcdrain() termios function.
3311 return send_break(tty
, 250);
3313 case TCSBRKP
: /* support for POSIX tcsendbreak() */
3314 return send_break(tty
, arg
? arg
*100 : 250);
3317 return tty_tiocmget(tty
, file
, p
);
3322 return tty_tiocmset(tty
, file
, cmd
, p
);
3324 if (tty
->driver
->ioctl
) {
3325 retval
= (tty
->driver
->ioctl
)(tty
, file
, cmd
, arg
);
3326 if (retval
!= -ENOIOCTLCMD
)
3329 ld
= tty_ldisc_ref_wait(tty
);
3332 retval
= ld
->ioctl(tty
, file
, cmd
, arg
);
3333 if (retval
== -ENOIOCTLCMD
)
3336 tty_ldisc_deref(ld
);
3342 * This implements the "Secure Attention Key" --- the idea is to
3343 * prevent trojan horses by killing all processes associated with this
3344 * tty when the user hits the "Secure Attention Key". Required for
3345 * super-paranoid applications --- see the Orange Book for more details.
3347 * This code could be nicer; ideally it should send a HUP, wait a few
3348 * seconds, then send a INT, and then a KILL signal. But you then
3349 * have to coordinate with the init process, since all processes associated
3350 * with the current tty must be dead before the new getty is allowed
3353 * Now, if it would be correct ;-/ The current code has a nasty hole -
3354 * it doesn't catch files in flight. We may send the descriptor to ourselves
3355 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3357 * Nasty bug: do_SAK is being called in interrupt context. This can
3358 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3360 void __do_SAK(struct tty_struct
*tty
)
3365 struct task_struct
*g
, *p
;
3366 struct pid
*session
;
3369 struct fdtable
*fdt
;
3373 session
= tty
->session
;
3375 tty_ldisc_flush(tty
);
3377 if (tty
->driver
->flush_buffer
)
3378 tty
->driver
->flush_buffer(tty
);
3380 read_lock(&tasklist_lock
);
3381 /* Kill the entire session */
3382 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
3383 printk(KERN_NOTICE
"SAK: killed process %d"
3384 " (%s): process_session(p)==tty->session\n",
3386 send_sig(SIGKILL
, p
, 1);
3387 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
3388 /* Now kill any processes that happen to have the
3391 do_each_thread(g
, p
) {
3392 if (p
->signal
->tty
== tty
) {
3393 printk(KERN_NOTICE
"SAK: killed process %d"
3394 " (%s): process_session(p)==tty->session\n",
3396 send_sig(SIGKILL
, p
, 1);
3402 * We don't take a ref to the file, so we must
3403 * hold ->file_lock instead.
3405 spin_lock(&p
->files
->file_lock
);
3406 fdt
= files_fdtable(p
->files
);
3407 for (i
=0; i
< fdt
->max_fds
; i
++) {
3408 filp
= fcheck_files(p
->files
, i
);
3411 if (filp
->f_op
->read
== tty_read
&&
3412 filp
->private_data
== tty
) {
3413 printk(KERN_NOTICE
"SAK: killed process %d"
3414 " (%s): fd#%d opened to the tty\n",
3415 p
->pid
, p
->comm
, i
);
3416 force_sig(SIGKILL
, p
);
3420 spin_unlock(&p
->files
->file_lock
);
3423 } while_each_thread(g
, p
);
3424 read_unlock(&tasklist_lock
);
3428 static void do_SAK_work(struct work_struct
*work
)
3430 struct tty_struct
*tty
=
3431 container_of(work
, struct tty_struct
, SAK_work
);
3436 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3437 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3438 * the values which we write to it will be identical to the values which it
3439 * already has. --akpm
3441 void do_SAK(struct tty_struct
*tty
)
3445 schedule_work(&tty
->SAK_work
);
3448 EXPORT_SYMBOL(do_SAK
);
3452 * @work: tty structure passed from work queue.
3454 * This routine is called out of the software interrupt to flush data
3455 * from the buffer chain to the line discipline.
3457 * Locking: holds tty->buf.lock to guard buffer list. Drops the lock
3458 * while invoking the line discipline receive_buf method. The
3459 * receive_buf method is single threaded for each tty instance.
3462 static void flush_to_ldisc(struct work_struct
*work
)
3464 struct tty_struct
*tty
=
3465 container_of(work
, struct tty_struct
, buf
.work
.work
);
3466 unsigned long flags
;
3467 struct tty_ldisc
*disc
;
3468 struct tty_buffer
*tbuf
, *head
;
3470 unsigned char *flag_buf
;
3472 disc
= tty_ldisc_ref(tty
);
3473 if (disc
== NULL
) /* !TTY_LDISC */
3476 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3477 head
= tty
->buf
.head
;
3479 tty
->buf
.head
= NULL
;
3481 int count
= head
->commit
- head
->read
;
3483 if (head
->next
== NULL
)
3487 tty_buffer_free(tty
, tbuf
);
3490 if (!tty
->receive_room
) {
3491 schedule_delayed_work(&tty
->buf
.work
, 1);
3494 if (count
> tty
->receive_room
)
3495 count
= tty
->receive_room
;
3496 char_buf
= head
->char_buf_ptr
+ head
->read
;
3497 flag_buf
= head
->flag_buf_ptr
+ head
->read
;
3498 head
->read
+= count
;
3499 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3500 disc
->receive_buf(tty
, char_buf
, flag_buf
, count
);
3501 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3503 tty
->buf
.head
= head
;
3505 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3507 tty_ldisc_deref(disc
);
3511 * tty_flip_buffer_push - terminal
3514 * Queue a push of the terminal flip buffers to the line discipline. This
3515 * function must not be called from IRQ context if tty->low_latency is set.
3517 * In the event of the queue being busy for flipping the work will be
3518 * held off and retried later.
3520 * Locking: tty buffer lock. Driver locks in low latency mode.
3523 void tty_flip_buffer_push(struct tty_struct
*tty
)
3525 unsigned long flags
;
3526 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3527 if (tty
->buf
.tail
!= NULL
)
3528 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
3529 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3531 if (tty
->low_latency
)
3532 flush_to_ldisc(&tty
->buf
.work
.work
);
3534 schedule_delayed_work(&tty
->buf
.work
, 1);
3537 EXPORT_SYMBOL(tty_flip_buffer_push
);
3541 * initialize_tty_struct
3542 * @tty: tty to initialize
3544 * This subroutine initializes a tty structure that has been newly
3547 * Locking: none - tty in question must not be exposed at this point
3550 static void initialize_tty_struct(struct tty_struct
*tty
)
3552 memset(tty
, 0, sizeof(struct tty_struct
));
3553 tty
->magic
= TTY_MAGIC
;
3554 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
3555 tty
->session
= NULL
;
3557 tty
->overrun_time
= jiffies
;
3558 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
3559 tty_buffer_init(tty
);
3560 INIT_DELAYED_WORK(&tty
->buf
.work
, flush_to_ldisc
);
3561 init_MUTEX(&tty
->buf
.pty_sem
);
3562 mutex_init(&tty
->termios_mutex
);
3563 init_waitqueue_head(&tty
->write_wait
);
3564 init_waitqueue_head(&tty
->read_wait
);
3565 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
3566 mutex_init(&tty
->atomic_read_lock
);
3567 mutex_init(&tty
->atomic_write_lock
);
3568 spin_lock_init(&tty
->read_lock
);
3569 INIT_LIST_HEAD(&tty
->tty_files
);
3570 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
3574 * The default put_char routine if the driver did not define one.
3577 static void tty_default_put_char(struct tty_struct
*tty
, unsigned char ch
)
3579 tty
->driver
->write(tty
, &ch
, 1);
3582 static struct class *tty_class
;
3585 * tty_register_device - register a tty device
3586 * @driver: the tty driver that describes the tty device
3587 * @index: the index in the tty driver for this tty device
3588 * @device: a struct device that is associated with this tty device.
3589 * This field is optional, if there is no known struct device
3590 * for this tty device it can be set to NULL safely.
3592 * Returns a pointer to the struct device for this tty device
3593 * (or ERR_PTR(-EFOO) on error).
3595 * This call is required to be made to register an individual tty device
3596 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3597 * that bit is not set, this function should not be called by a tty
3603 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3604 struct device
*device
)
3607 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3609 if (index
>= driver
->num
) {
3610 printk(KERN_ERR
"Attempt to register invalid tty line number "
3612 return ERR_PTR(-EINVAL
);
3615 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3616 pty_line_name(driver
, index
, name
);
3618 tty_line_name(driver
, index
, name
);
3620 return device_create(tty_class
, device
, dev
, name
);
3624 * tty_unregister_device - unregister a tty device
3625 * @driver: the tty driver that describes the tty device
3626 * @index: the index in the tty driver for this tty device
3628 * If a tty device is registered with a call to tty_register_device() then
3629 * this function must be called when the tty device is gone.
3634 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3636 device_destroy(tty_class
, MKDEV(driver
->major
, driver
->minor_start
) + index
);
3639 EXPORT_SYMBOL(tty_register_device
);
3640 EXPORT_SYMBOL(tty_unregister_device
);
3642 struct tty_driver
*alloc_tty_driver(int lines
)
3644 struct tty_driver
*driver
;
3646 driver
= kmalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3648 memset(driver
, 0, sizeof(struct tty_driver
));
3649 driver
->magic
= TTY_DRIVER_MAGIC
;
3650 driver
->num
= lines
;
3651 /* later we'll move allocation of tables here */
3656 void put_tty_driver(struct tty_driver
*driver
)
3661 void tty_set_operations(struct tty_driver
*driver
,
3662 const struct tty_operations
*op
)
3664 driver
->open
= op
->open
;
3665 driver
->close
= op
->close
;
3666 driver
->write
= op
->write
;
3667 driver
->put_char
= op
->put_char
;
3668 driver
->flush_chars
= op
->flush_chars
;
3669 driver
->write_room
= op
->write_room
;
3670 driver
->chars_in_buffer
= op
->chars_in_buffer
;
3671 driver
->ioctl
= op
->ioctl
;
3672 driver
->set_termios
= op
->set_termios
;
3673 driver
->throttle
= op
->throttle
;
3674 driver
->unthrottle
= op
->unthrottle
;
3675 driver
->stop
= op
->stop
;
3676 driver
->start
= op
->start
;
3677 driver
->hangup
= op
->hangup
;
3678 driver
->break_ctl
= op
->break_ctl
;
3679 driver
->flush_buffer
= op
->flush_buffer
;
3680 driver
->set_ldisc
= op
->set_ldisc
;
3681 driver
->wait_until_sent
= op
->wait_until_sent
;
3682 driver
->send_xchar
= op
->send_xchar
;
3683 driver
->read_proc
= op
->read_proc
;
3684 driver
->write_proc
= op
->write_proc
;
3685 driver
->tiocmget
= op
->tiocmget
;
3686 driver
->tiocmset
= op
->tiocmset
;
3690 EXPORT_SYMBOL(alloc_tty_driver
);
3691 EXPORT_SYMBOL(put_tty_driver
);
3692 EXPORT_SYMBOL(tty_set_operations
);
3695 * Called by a tty driver to register itself.
3697 int tty_register_driver(struct tty_driver
*driver
)
3704 if (driver
->flags
& TTY_DRIVER_INSTALLED
)
3707 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
3708 p
= kmalloc(driver
->num
* 3 * sizeof(void *), GFP_KERNEL
);
3711 memset(p
, 0, driver
->num
* 3 * sizeof(void *));
3714 if (!driver
->major
) {
3715 error
= alloc_chrdev_region(&dev
, driver
->minor_start
, driver
->num
,
3716 (char*)driver
->name
);
3718 driver
->major
= MAJOR(dev
);
3719 driver
->minor_start
= MINOR(dev
);
3722 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3723 error
= register_chrdev_region(dev
, driver
->num
,
3724 (char*)driver
->name
);
3732 driver
->ttys
= (struct tty_struct
**)p
;
3733 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
3734 driver
->termios_locked
= (struct ktermios
**)(p
+ driver
->num
* 2);
3736 driver
->ttys
= NULL
;
3737 driver
->termios
= NULL
;
3738 driver
->termios_locked
= NULL
;
3741 cdev_init(&driver
->cdev
, &tty_fops
);
3742 driver
->cdev
.owner
= driver
->owner
;
3743 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
3745 unregister_chrdev_region(dev
, driver
->num
);
3746 driver
->ttys
= NULL
;
3747 driver
->termios
= driver
->termios_locked
= NULL
;
3752 if (!driver
->put_char
)
3753 driver
->put_char
= tty_default_put_char
;
3755 list_add(&driver
->tty_drivers
, &tty_drivers
);
3757 if ( !(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
) ) {
3758 for(i
= 0; i
< driver
->num
; i
++)
3759 tty_register_device(driver
, i
, NULL
);
3761 proc_tty_register_driver(driver
);
3765 EXPORT_SYMBOL(tty_register_driver
);
3768 * Called by a tty driver to unregister itself.
3770 int tty_unregister_driver(struct tty_driver
*driver
)
3773 struct ktermios
*tp
;
3776 if (driver
->refcount
)
3779 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3782 list_del(&driver
->tty_drivers
);
3785 * Free the termios and termios_locked structures because
3786 * we don't want to get memory leaks when modular tty
3787 * drivers are removed from the kernel.
3789 for (i
= 0; i
< driver
->num
; i
++) {
3790 tp
= driver
->termios
[i
];
3792 driver
->termios
[i
] = NULL
;
3795 tp
= driver
->termios_locked
[i
];
3797 driver
->termios_locked
[i
] = NULL
;
3800 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3801 tty_unregister_device(driver
, i
);
3804 proc_tty_unregister_driver(driver
);
3805 driver
->ttys
= NULL
;
3806 driver
->termios
= driver
->termios_locked
= NULL
;
3808 cdev_del(&driver
->cdev
);
3811 EXPORT_SYMBOL(tty_unregister_driver
);
3813 dev_t
tty_devnum(struct tty_struct
*tty
)
3815 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3817 EXPORT_SYMBOL(tty_devnum
);
3819 void proc_clear_tty(struct task_struct
*p
)
3821 spin_lock_irq(&p
->sighand
->siglock
);
3822 p
->signal
->tty
= NULL
;
3823 spin_unlock_irq(&p
->sighand
->siglock
);
3825 EXPORT_SYMBOL(proc_clear_tty
);
3827 static struct pid
*__proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3829 struct pid
*old_pgrp
;
3831 tty
->session
= get_pid(task_session(tsk
));
3832 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3834 old_pgrp
= tsk
->signal
->tty_old_pgrp
;
3835 tsk
->signal
->tty
= tty
;
3836 tsk
->signal
->tty_old_pgrp
= NULL
;
3840 void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3842 struct pid
*old_pgrp
;
3844 spin_lock_irq(&tsk
->sighand
->siglock
);
3845 old_pgrp
= __proc_set_tty(tsk
, tty
);
3846 spin_unlock_irq(&tsk
->sighand
->siglock
);
3851 struct tty_struct
*get_current_tty(void)
3853 struct tty_struct
*tty
;
3854 WARN_ON_ONCE(!mutex_is_locked(&tty_mutex
));
3855 tty
= current
->signal
->tty
;
3857 * session->tty can be changed/cleared from under us, make sure we
3858 * issue the load. The obtained pointer, when not NULL, is valid as
3859 * long as we hold tty_mutex.
3864 EXPORT_SYMBOL_GPL(get_current_tty
);
3867 * Initialize the console device. This is called *early*, so
3868 * we can't necessarily depend on lots of kernel help here.
3869 * Just do some early initializations, and do the complex setup
3872 void __init
console_init(void)
3876 /* Setup the default TTY line discipline. */
3877 (void) tty_register_ldisc(N_TTY
, &tty_ldisc_N_TTY
);
3880 * set up the console device so that later boot sequences can
3881 * inform about problems etc..
3883 #ifdef CONFIG_EARLY_PRINTK
3884 disable_early_printk();
3886 call
= __con_initcall_start
;
3887 while (call
< __con_initcall_end
) {
3894 extern int vty_init(void);
3897 static int __init
tty_class_init(void)
3899 tty_class
= class_create(THIS_MODULE
, "tty");
3900 if (IS_ERR(tty_class
))
3901 return PTR_ERR(tty_class
);
3905 postcore_initcall(tty_class_init
);
3907 /* 3/2004 jmc: why do these devices exist? */
3909 static struct cdev tty_cdev
, console_cdev
;
3910 #ifdef CONFIG_UNIX98_PTYS
3911 static struct cdev ptmx_cdev
;
3914 static struct cdev vc0_cdev
;
3918 * Ok, now we can initialize the rest of the tty devices and can count
3919 * on memory allocations, interrupts etc..
3921 static int __init
tty_init(void)
3923 cdev_init(&tty_cdev
, &tty_fops
);
3924 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3925 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3926 panic("Couldn't register /dev/tty driver\n");
3927 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), "tty");
3929 cdev_init(&console_cdev
, &console_fops
);
3930 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3931 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3932 panic("Couldn't register /dev/console driver\n");
3933 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), "console");
3935 #ifdef CONFIG_UNIX98_PTYS
3936 cdev_init(&ptmx_cdev
, &ptmx_fops
);
3937 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
3938 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
3939 panic("Couldn't register /dev/ptmx driver\n");
3940 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), "ptmx");
3944 cdev_init(&vc0_cdev
, &console_fops
);
3945 if (cdev_add(&vc0_cdev
, MKDEV(TTY_MAJOR
, 0), 1) ||
3946 register_chrdev_region(MKDEV(TTY_MAJOR
, 0), 1, "/dev/vc/0") < 0)
3947 panic("Couldn't register /dev/tty0 driver\n");
3948 device_create(tty_class
, NULL
, MKDEV(TTY_MAJOR
, 0), "tty0");
3954 module_init(tty_init
);