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 static void initialize_tty_struct(struct tty_struct
*tty
);
146 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
147 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
148 ssize_t
redirected_tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
149 static unsigned int tty_poll(struct file
*, poll_table
*);
150 static int tty_open(struct inode
*, struct file
*);
151 static int tty_release(struct inode
*, struct file
*);
152 int tty_ioctl(struct inode
* inode
, struct file
* file
,
153 unsigned int cmd
, unsigned long arg
);
155 static long tty_compat_ioctl(struct file
* file
, unsigned int cmd
,
158 #define tty_compat_ioctl NULL
160 static int tty_fasync(int fd
, struct file
* filp
, int on
);
161 static void release_tty(struct tty_struct
*tty
, int idx
);
162 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
163 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
166 * alloc_tty_struct - allocate a tty object
168 * Return a new empty tty structure. The data fields have not
169 * been initialized in any way but has been zeroed
174 static struct tty_struct
*alloc_tty_struct(void)
176 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
179 static void tty_buffer_free_all(struct tty_struct
*);
182 * free_tty_struct - free a disused tty
183 * @tty: tty struct to free
185 * Free the write buffers, tty queue and tty memory itself.
187 * Locking: none. Must be called after tty is definitely unused
190 static inline void free_tty_struct(struct tty_struct
*tty
)
192 kfree(tty
->write_buf
);
193 tty_buffer_free_all(tty
);
197 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
200 * tty_name - return tty naming
201 * @tty: tty structure
202 * @buf: buffer for output
204 * Convert a tty structure into a name. The name reflects the kernel
205 * naming policy and if udev is in use may not reflect user space
210 char *tty_name(struct tty_struct
*tty
, char *buf
)
212 if (!tty
) /* Hmm. NULL pointer. That's fun. */
213 strcpy(buf
, "NULL tty");
215 strcpy(buf
, tty
->name
);
219 EXPORT_SYMBOL(tty_name
);
221 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
224 #ifdef TTY_PARANOIA_CHECK
227 "null TTY for (%d:%d) in %s\n",
228 imajor(inode
), iminor(inode
), routine
);
231 if (tty
->magic
!= TTY_MAGIC
) {
233 "bad magic number for tty struct (%d:%d) in %s\n",
234 imajor(inode
), iminor(inode
), routine
);
241 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
243 #ifdef CHECK_TTY_COUNT
248 list_for_each(p
, &tty
->tty_files
) {
252 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
253 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
254 tty
->link
&& tty
->link
->count
)
256 if (tty
->count
!= count
) {
257 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
258 "!= #fd's(%d) in %s\n",
259 tty
->name
, tty
->count
, count
, routine
);
267 * Tty buffer allocation management
271 * tty_buffer_free_all - free buffers used by a tty
272 * @tty: tty to free from
274 * Remove all the buffers pending on a tty whether queued with data
275 * or in the free ring. Must be called when the tty is no longer in use
280 static void tty_buffer_free_all(struct tty_struct
*tty
)
282 struct tty_buffer
*thead
;
283 while((thead
= tty
->buf
.head
) != NULL
) {
284 tty
->buf
.head
= thead
->next
;
287 while((thead
= tty
->buf
.free
) != NULL
) {
288 tty
->buf
.free
= thead
->next
;
291 tty
->buf
.tail
= NULL
;
292 tty
->buf
.memory_used
= 0;
296 * tty_buffer_init - prepare a tty buffer structure
297 * @tty: tty to initialise
299 * Set up the initial state of the buffer management for a tty device.
300 * Must be called before the other tty buffer functions are used.
305 static void tty_buffer_init(struct tty_struct
*tty
)
307 spin_lock_init(&tty
->buf
.lock
);
308 tty
->buf
.head
= NULL
;
309 tty
->buf
.tail
= NULL
;
310 tty
->buf
.free
= NULL
;
311 tty
->buf
.memory_used
= 0;
315 * tty_buffer_alloc - allocate a tty buffer
317 * @size: desired size (characters)
319 * Allocate a new tty buffer to hold the desired number of characters.
320 * Return NULL if out of memory or the allocation would exceed the
323 * Locking: Caller must hold tty->buf.lock
326 static struct tty_buffer
*tty_buffer_alloc(struct tty_struct
*tty
, size_t size
)
328 struct tty_buffer
*p
;
330 if (tty
->buf
.memory_used
+ size
> 65536)
332 p
= kmalloc(sizeof(struct tty_buffer
) + 2 * size
, GFP_ATOMIC
);
340 p
->char_buf_ptr
= (char *)(p
->data
);
341 p
->flag_buf_ptr
= (unsigned char *)p
->char_buf_ptr
+ size
;
342 tty
->buf
.memory_used
+= size
;
347 * tty_buffer_free - free a tty buffer
348 * @tty: tty owning the buffer
349 * @b: the buffer to free
351 * Free a tty buffer, or add it to the free list according to our
354 * Locking: Caller must hold tty->buf.lock
357 static void tty_buffer_free(struct tty_struct
*tty
, struct tty_buffer
*b
)
359 /* Dumb strategy for now - should keep some stats */
360 tty
->buf
.memory_used
-= b
->size
;
361 WARN_ON(tty
->buf
.memory_used
< 0);
366 b
->next
= tty
->buf
.free
;
372 * tty_buffer_flush - flush full tty buffers
375 * flush all the buffers containing receive data
380 static void tty_buffer_flush(struct tty_struct
*tty
)
382 struct tty_buffer
*thead
;
385 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
386 while((thead
= tty
->buf
.head
) != NULL
) {
387 tty
->buf
.head
= thead
->next
;
388 tty_buffer_free(tty
, thead
);
390 tty
->buf
.tail
= NULL
;
391 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
395 * tty_buffer_find - find a free tty buffer
396 * @tty: tty owning the buffer
397 * @size: characters wanted
399 * Locate an existing suitable tty buffer or if we are lacking one then
400 * allocate a new one. We round our buffers off in 256 character chunks
401 * to get better allocation behaviour.
403 * Locking: Caller must hold tty->buf.lock
406 static struct tty_buffer
*tty_buffer_find(struct tty_struct
*tty
, size_t size
)
408 struct tty_buffer
**tbh
= &tty
->buf
.free
;
409 while((*tbh
) != NULL
) {
410 struct tty_buffer
*t
= *tbh
;
411 if(t
->size
>= size
) {
417 tty
->buf
.memory_used
+= t
->size
;
420 tbh
= &((*tbh
)->next
);
422 /* Round the buffer size out */
423 size
= (size
+ 0xFF) & ~ 0xFF;
424 return tty_buffer_alloc(tty
, size
);
425 /* Should possibly check if this fails for the largest buffer we
426 have queued and recycle that ? */
430 * tty_buffer_request_room - grow tty buffer if needed
431 * @tty: tty structure
432 * @size: size desired
434 * Make at least size bytes of linear space available for the tty
435 * buffer. If we fail return the size we managed to find.
437 * Locking: Takes tty->buf.lock
439 int tty_buffer_request_room(struct tty_struct
*tty
, size_t size
)
441 struct tty_buffer
*b
, *n
;
445 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
447 /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
448 remove this conditional if its worth it. This would be invisible
450 if ((b
= tty
->buf
.tail
) != NULL
)
451 left
= b
->size
- b
->used
;
456 /* This is the slow path - looking for new buffers to use */
457 if ((n
= tty_buffer_find(tty
, size
)) != NULL
) {
468 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
471 EXPORT_SYMBOL_GPL(tty_buffer_request_room
);
474 * tty_insert_flip_string - Add characters to the tty buffer
475 * @tty: tty structure
479 * Queue a series of bytes to the tty buffering. All the characters
480 * passed are marked as without error. Returns the number added.
482 * Locking: Called functions may take tty->buf.lock
485 int tty_insert_flip_string(struct tty_struct
*tty
, const unsigned char *chars
,
490 int space
= tty_buffer_request_room(tty
, size
- copied
);
491 struct tty_buffer
*tb
= tty
->buf
.tail
;
492 /* If there is no space then tb may be NULL */
493 if(unlikely(space
== 0))
495 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
496 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
500 /* There is a small chance that we need to split the data over
501 several buffers. If this is the case we must loop */
502 } while (unlikely(size
> copied
));
505 EXPORT_SYMBOL(tty_insert_flip_string
);
508 * tty_insert_flip_string_flags - Add characters to the tty buffer
509 * @tty: tty structure
514 * Queue a series of bytes to the tty buffering. For each character
515 * the flags array indicates the status of the character. Returns the
518 * Locking: Called functions may take tty->buf.lock
521 int tty_insert_flip_string_flags(struct tty_struct
*tty
,
522 const unsigned char *chars
, const char *flags
, size_t size
)
526 int space
= tty_buffer_request_room(tty
, size
- copied
);
527 struct tty_buffer
*tb
= tty
->buf
.tail
;
528 /* If there is no space then tb may be NULL */
529 if(unlikely(space
== 0))
531 memcpy(tb
->char_buf_ptr
+ tb
->used
, chars
, space
);
532 memcpy(tb
->flag_buf_ptr
+ tb
->used
, flags
, space
);
537 /* There is a small chance that we need to split the data over
538 several buffers. If this is the case we must loop */
539 } while (unlikely(size
> copied
));
542 EXPORT_SYMBOL(tty_insert_flip_string_flags
);
545 * tty_schedule_flip - push characters to ldisc
546 * @tty: tty to push from
548 * Takes any pending buffers and transfers their ownership to the
549 * ldisc side of the queue. It then schedules those characters for
550 * processing by the line discipline.
552 * Locking: Takes tty->buf.lock
555 void tty_schedule_flip(struct tty_struct
*tty
)
558 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
559 if (tty
->buf
.tail
!= NULL
)
560 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
561 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
562 schedule_delayed_work(&tty
->buf
.work
, 1);
564 EXPORT_SYMBOL(tty_schedule_flip
);
567 * tty_prepare_flip_string - make room for characters
569 * @chars: return pointer for character write area
570 * @size: desired size
572 * Prepare a block of space in the buffer for data. Returns the length
573 * available and buffer pointer to the space which is now allocated and
574 * accounted for as ready for normal characters. This is used for drivers
575 * that need their own block copy routines into the buffer. There is no
576 * guarantee the buffer is a DMA target!
578 * Locking: May call functions taking tty->buf.lock
581 int tty_prepare_flip_string(struct tty_struct
*tty
, unsigned char **chars
, size_t size
)
583 int space
= tty_buffer_request_room(tty
, size
);
585 struct tty_buffer
*tb
= tty
->buf
.tail
;
586 *chars
= tb
->char_buf_ptr
+ tb
->used
;
587 memset(tb
->flag_buf_ptr
+ tb
->used
, TTY_NORMAL
, space
);
593 EXPORT_SYMBOL_GPL(tty_prepare_flip_string
);
596 * tty_prepare_flip_string_flags - make room for characters
598 * @chars: return pointer for character write area
599 * @flags: return pointer for status flag write area
600 * @size: desired size
602 * Prepare a block of space in the buffer for data. Returns the length
603 * available and buffer pointer to the space which is now allocated and
604 * accounted for as ready for characters. This is used for drivers
605 * that need their own block copy routines into the buffer. There is no
606 * guarantee the buffer is a DMA target!
608 * Locking: May call functions taking tty->buf.lock
611 int tty_prepare_flip_string_flags(struct tty_struct
*tty
, unsigned char **chars
, char **flags
, size_t size
)
613 int space
= tty_buffer_request_room(tty
, size
);
615 struct tty_buffer
*tb
= tty
->buf
.tail
;
616 *chars
= tb
->char_buf_ptr
+ tb
->used
;
617 *flags
= tb
->flag_buf_ptr
+ tb
->used
;
623 EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags
);
628 * tty_set_termios_ldisc - set ldisc field
629 * @tty: tty structure
630 * @num: line discipline number
632 * This is probably overkill for real world processors but
633 * they are not on hot paths so a little discipline won't do
636 * Locking: takes termios_mutex
639 static void tty_set_termios_ldisc(struct tty_struct
*tty
, int num
)
641 mutex_lock(&tty
->termios_mutex
);
642 tty
->termios
->c_line
= num
;
643 mutex_unlock(&tty
->termios_mutex
);
647 * This guards the refcounted line discipline lists. The lock
648 * must be taken with irqs off because there are hangup path
649 * callers who will do ldisc lookups and cannot sleep.
652 static DEFINE_SPINLOCK(tty_ldisc_lock
);
653 static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait
);
654 static struct tty_ldisc tty_ldiscs
[NR_LDISCS
]; /* line disc dispatch table */
657 * tty_register_ldisc - install a line discipline
658 * @disc: ldisc number
659 * @new_ldisc: pointer to the ldisc object
661 * Installs a new line discipline into the kernel. The discipline
662 * is set up as unreferenced and then made available to the kernel
663 * from this point onwards.
666 * takes tty_ldisc_lock to guard against ldisc races
669 int tty_register_ldisc(int disc
, struct tty_ldisc
*new_ldisc
)
674 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
677 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
678 tty_ldiscs
[disc
] = *new_ldisc
;
679 tty_ldiscs
[disc
].num
= disc
;
680 tty_ldiscs
[disc
].flags
|= LDISC_FLAG_DEFINED
;
681 tty_ldiscs
[disc
].refcount
= 0;
682 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
686 EXPORT_SYMBOL(tty_register_ldisc
);
689 * tty_unregister_ldisc - unload a line discipline
690 * @disc: ldisc number
691 * @new_ldisc: pointer to the ldisc object
693 * Remove a line discipline from the kernel providing it is not
697 * takes tty_ldisc_lock to guard against ldisc races
700 int tty_unregister_ldisc(int disc
)
705 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
708 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
709 if (tty_ldiscs
[disc
].refcount
)
712 tty_ldiscs
[disc
].flags
&= ~LDISC_FLAG_DEFINED
;
713 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
717 EXPORT_SYMBOL(tty_unregister_ldisc
);
720 * tty_ldisc_get - take a reference to an ldisc
721 * @disc: ldisc number
723 * Takes a reference to a line discipline. Deals with refcounts and
724 * module locking counts. Returns NULL if the discipline is not available.
725 * Returns a pointer to the discipline and bumps the ref count if it is
729 * takes tty_ldisc_lock to guard against ldisc races
732 struct tty_ldisc
*tty_ldisc_get(int disc
)
735 struct tty_ldisc
*ld
;
737 if (disc
< N_TTY
|| disc
>= NR_LDISCS
)
740 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
742 ld
= &tty_ldiscs
[disc
];
743 /* Check the entry is defined */
744 if(ld
->flags
& LDISC_FLAG_DEFINED
)
746 /* If the module is being unloaded we can't use it */
747 if (!try_module_get(ld
->owner
))
754 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
758 EXPORT_SYMBOL_GPL(tty_ldisc_get
);
761 * tty_ldisc_put - drop ldisc reference
762 * @disc: ldisc number
764 * Drop a reference to a line discipline. Manage refcounts and
765 * module usage counts
768 * takes tty_ldisc_lock to guard against ldisc races
771 void tty_ldisc_put(int disc
)
773 struct tty_ldisc
*ld
;
776 BUG_ON(disc
< N_TTY
|| disc
>= NR_LDISCS
);
778 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
779 ld
= &tty_ldiscs
[disc
];
780 BUG_ON(ld
->refcount
== 0);
782 module_put(ld
->owner
);
783 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
786 EXPORT_SYMBOL_GPL(tty_ldisc_put
);
789 * tty_ldisc_assign - set ldisc on a tty
790 * @tty: tty to assign
791 * @ld: line discipline
793 * Install an instance of a line discipline into a tty structure. The
794 * ldisc must have a reference count above zero to ensure it remains/
795 * The tty instance refcount starts at zero.
798 * Caller must hold references
801 static void tty_ldisc_assign(struct tty_struct
*tty
, struct tty_ldisc
*ld
)
804 tty
->ldisc
.refcount
= 0;
808 * tty_ldisc_try - internal helper
811 * Make a single attempt to grab and bump the refcount on
812 * the tty ldisc. Return 0 on failure or 1 on success. This is
813 * used to implement both the waiting and non waiting versions
816 * Locking: takes tty_ldisc_lock
819 static int tty_ldisc_try(struct tty_struct
*tty
)
822 struct tty_ldisc
*ld
;
825 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
827 if(test_bit(TTY_LDISC
, &tty
->flags
))
832 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
837 * tty_ldisc_ref_wait - wait for 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 * wait patiently until it changes.
844 * Note: Must not be called from an IRQ/timer context. The caller
845 * must also be careful not to hold other locks that will deadlock
846 * against a discipline change, such as an existing ldisc reference
847 * (which we check for)
849 * Locking: call functions take tty_ldisc_lock
852 struct tty_ldisc
*tty_ldisc_ref_wait(struct tty_struct
*tty
)
854 /* wait_event is a macro */
855 wait_event(tty_ldisc_wait
, tty_ldisc_try(tty
));
856 if(tty
->ldisc
.refcount
== 0)
857 printk(KERN_ERR
"tty_ldisc_ref_wait\n");
861 EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait
);
864 * tty_ldisc_ref - get the tty ldisc
867 * Dereference the line discipline for the terminal and take a
868 * reference to it. If the line discipline is in flux then
869 * return NULL. Can be called from IRQ and timer functions.
871 * Locking: called functions take tty_ldisc_lock
874 struct tty_ldisc
*tty_ldisc_ref(struct tty_struct
*tty
)
876 if(tty_ldisc_try(tty
))
881 EXPORT_SYMBOL_GPL(tty_ldisc_ref
);
884 * tty_ldisc_deref - free a tty ldisc reference
885 * @ld: reference to free up
887 * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
888 * be called in IRQ context.
890 * Locking: takes tty_ldisc_lock
893 void tty_ldisc_deref(struct tty_ldisc
*ld
)
899 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
900 if(ld
->refcount
== 0)
901 printk(KERN_ERR
"tty_ldisc_deref: no references.\n");
904 if(ld
->refcount
== 0)
905 wake_up(&tty_ldisc_wait
);
906 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
909 EXPORT_SYMBOL_GPL(tty_ldisc_deref
);
912 * tty_ldisc_enable - allow ldisc use
913 * @tty: terminal to activate ldisc on
915 * Set the TTY_LDISC flag when the line discipline can be called
916 * again. Do neccessary wakeups for existing sleepers.
918 * Note: nobody should set this bit except via this function. Clearing
919 * directly is allowed.
922 static void tty_ldisc_enable(struct tty_struct
*tty
)
924 set_bit(TTY_LDISC
, &tty
->flags
);
925 wake_up(&tty_ldisc_wait
);
929 * tty_set_ldisc - set line discipline
930 * @tty: the terminal to set
931 * @ldisc: the line discipline
933 * Set the discipline of a tty line. Must be called from a process
936 * Locking: takes tty_ldisc_lock.
937 * called functions take termios_mutex
940 static int tty_set_ldisc(struct tty_struct
*tty
, int ldisc
)
943 struct tty_ldisc o_ldisc
;
947 struct tty_ldisc
*ld
;
948 struct tty_struct
*o_tty
;
950 if ((ldisc
< N_TTY
) || (ldisc
>= NR_LDISCS
))
955 ld
= tty_ldisc_get(ldisc
);
956 /* Eduardo Blanco <ejbs@cs.cs.com.uy> */
957 /* Cyrus Durgin <cider@speakeasy.org> */
959 request_module("tty-ldisc-%d", ldisc
);
960 ld
= tty_ldisc_get(ldisc
);
966 * Problem: What do we do if this blocks ?
969 tty_wait_until_sent(tty
, 0);
971 if (tty
->ldisc
.num
== ldisc
) {
972 tty_ldisc_put(ldisc
);
977 * No more input please, we are switching. The new ldisc
978 * will update this value in the ldisc open function
981 tty
->receive_room
= 0;
983 o_ldisc
= tty
->ldisc
;
987 * Make sure we don't change while someone holds a
988 * reference to the line discipline. The TTY_LDISC bit
989 * prevents anyone taking a reference once it is clear.
990 * We need the lock to avoid racing reference takers.
993 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
994 if (tty
->ldisc
.refcount
|| (o_tty
&& o_tty
->ldisc
.refcount
)) {
995 if(tty
->ldisc
.refcount
) {
996 /* Free the new ldisc we grabbed. Must drop the lock
998 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
999 tty_ldisc_put(ldisc
);
1001 * There are several reasons we may be busy, including
1002 * random momentary I/O traffic. We must therefore
1003 * retry. We could distinguish between blocking ops
1004 * and retries if we made tty_ldisc_wait() smarter. That
1005 * is up for discussion.
1007 if (wait_event_interruptible(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0) < 0)
1008 return -ERESTARTSYS
;
1011 if(o_tty
&& o_tty
->ldisc
.refcount
) {
1012 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1013 tty_ldisc_put(ldisc
);
1014 if (wait_event_interruptible(tty_ldisc_wait
, o_tty
->ldisc
.refcount
== 0) < 0)
1015 return -ERESTARTSYS
;
1020 /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */
1022 if (!test_bit(TTY_LDISC
, &tty
->flags
)) {
1023 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1024 tty_ldisc_put(ldisc
);
1025 ld
= tty_ldisc_ref_wait(tty
);
1026 tty_ldisc_deref(ld
);
1030 clear_bit(TTY_LDISC
, &tty
->flags
);
1032 clear_bit(TTY_LDISC
, &o_tty
->flags
);
1033 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
1036 * From this point on we know nobody has an ldisc
1037 * usage reference, nor can they obtain one until
1038 * we say so later on.
1041 work
= cancel_delayed_work(&tty
->buf
.work
);
1043 * Wait for ->hangup_work and ->buf.work handlers to terminate
1046 flush_scheduled_work();
1047 /* Shutdown the current discipline. */
1048 if (tty
->ldisc
.close
)
1049 (tty
->ldisc
.close
)(tty
);
1051 /* Now set up the new line discipline. */
1052 tty_ldisc_assign(tty
, ld
);
1053 tty_set_termios_ldisc(tty
, ldisc
);
1054 if (tty
->ldisc
.open
)
1055 retval
= (tty
->ldisc
.open
)(tty
);
1057 tty_ldisc_put(ldisc
);
1058 /* There is an outstanding reference here so this is safe */
1059 tty_ldisc_assign(tty
, tty_ldisc_get(o_ldisc
.num
));
1060 tty_set_termios_ldisc(tty
, tty
->ldisc
.num
);
1061 if (tty
->ldisc
.open
&& (tty
->ldisc
.open(tty
) < 0)) {
1062 tty_ldisc_put(o_ldisc
.num
);
1063 /* This driver is always present */
1064 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
1065 tty_set_termios_ldisc(tty
, N_TTY
);
1066 if (tty
->ldisc
.open
) {
1067 int r
= tty
->ldisc
.open(tty
);
1070 panic("Couldn't open N_TTY ldisc for "
1072 tty_name(tty
, buf
), r
);
1076 /* At this point we hold a reference to the new ldisc and a
1077 a reference to the old ldisc. If we ended up flipping back
1078 to the existing ldisc we have two references to it */
1080 if (tty
->ldisc
.num
!= o_ldisc
.num
&& tty
->driver
->set_ldisc
)
1081 tty
->driver
->set_ldisc(tty
);
1083 tty_ldisc_put(o_ldisc
.num
);
1086 * Allow ldisc referencing to occur as soon as the driver
1087 * ldisc callback completes.
1090 tty_ldisc_enable(tty
);
1092 tty_ldisc_enable(o_tty
);
1094 /* Restart it in case no characters kick it off. Safe if
1097 schedule_delayed_work(&tty
->buf
.work
, 1);
1102 * get_tty_driver - find device of a tty
1103 * @dev_t: device identifier
1104 * @index: returns the index of the tty
1106 * This routine returns a tty driver structure, given a device number
1107 * and also passes back the index number.
1109 * Locking: caller must hold tty_mutex
1112 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
1114 struct tty_driver
*p
;
1116 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
1117 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
1118 if (device
< base
|| device
>= base
+ p
->num
)
1120 *index
= device
- base
;
1127 * tty_check_change - check for POSIX terminal changes
1128 * @tty: tty to check
1130 * If we try to write to, or set the state of, a terminal and we're
1131 * not in the foreground, send a SIGTTOU. If the signal is blocked or
1132 * ignored, go ahead and perform the operation. (POSIX 7.2)
1137 int tty_check_change(struct tty_struct
* tty
)
1139 if (current
->signal
->tty
!= tty
)
1142 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
1145 if (task_pgrp(current
) == tty
->pgrp
)
1147 if (is_ignored(SIGTTOU
))
1149 if (is_current_pgrp_orphaned())
1151 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
1152 set_thread_flag(TIF_SIGPENDING
);
1153 return -ERESTARTSYS
;
1156 EXPORT_SYMBOL(tty_check_change
);
1158 static ssize_t
hung_up_tty_read(struct file
* file
, char __user
* buf
,
1159 size_t count
, loff_t
*ppos
)
1164 static ssize_t
hung_up_tty_write(struct file
* file
, const char __user
* buf
,
1165 size_t count
, loff_t
*ppos
)
1170 /* No kernel lock held - none needed ;) */
1171 static unsigned int hung_up_tty_poll(struct file
* filp
, poll_table
* wait
)
1173 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
1176 static long hung_up_tty_ioctl(struct file
* file
,
1177 unsigned int cmd
, unsigned long arg
)
1179 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
1182 static const struct file_operations tty_fops
= {
1183 .llseek
= no_llseek
,
1188 .compat_ioctl
= tty_compat_ioctl
,
1190 .release
= tty_release
,
1191 .fasync
= tty_fasync
,
1194 #ifdef CONFIG_UNIX98_PTYS
1195 static const struct file_operations ptmx_fops
= {
1196 .llseek
= no_llseek
,
1201 .compat_ioctl
= tty_compat_ioctl
,
1203 .release
= tty_release
,
1204 .fasync
= tty_fasync
,
1208 static const struct file_operations console_fops
= {
1209 .llseek
= no_llseek
,
1211 .write
= redirected_tty_write
,
1214 .compat_ioctl
= tty_compat_ioctl
,
1216 .release
= tty_release
,
1217 .fasync
= tty_fasync
,
1220 static const struct file_operations hung_up_tty_fops
= {
1221 .llseek
= no_llseek
,
1222 .read
= hung_up_tty_read
,
1223 .write
= hung_up_tty_write
,
1224 .poll
= hung_up_tty_poll
,
1225 .unlocked_ioctl
= hung_up_tty_ioctl
,
1226 .compat_ioctl
= hung_up_tty_ioctl
,
1227 .release
= tty_release
,
1230 static DEFINE_SPINLOCK(redirect_lock
);
1231 static struct file
*redirect
;
1234 * tty_wakeup - request more data
1237 * Internal and external helper for wakeups of tty. This function
1238 * informs the line discipline if present that the driver is ready
1239 * to receive more output data.
1242 void tty_wakeup(struct tty_struct
*tty
)
1244 struct tty_ldisc
*ld
;
1246 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
1247 ld
= tty_ldisc_ref(tty
);
1249 if(ld
->write_wakeup
)
1250 ld
->write_wakeup(tty
);
1251 tty_ldisc_deref(ld
);
1254 wake_up_interruptible(&tty
->write_wait
);
1257 EXPORT_SYMBOL_GPL(tty_wakeup
);
1260 * tty_ldisc_flush - flush line discipline queue
1263 * Flush the line discipline queue (if any) for this tty. If there
1264 * is no line discipline active this is a no-op.
1267 void tty_ldisc_flush(struct tty_struct
*tty
)
1269 struct tty_ldisc
*ld
= tty_ldisc_ref(tty
);
1271 if(ld
->flush_buffer
)
1272 ld
->flush_buffer(tty
);
1273 tty_ldisc_deref(ld
);
1275 tty_buffer_flush(tty
);
1278 EXPORT_SYMBOL_GPL(tty_ldisc_flush
);
1281 * tty_reset_termios - reset terminal state
1282 * @tty: tty to reset
1284 * Restore a terminal to the driver default state
1287 static void tty_reset_termios(struct tty_struct
*tty
)
1289 mutex_lock(&tty
->termios_mutex
);
1290 *tty
->termios
= tty
->driver
->init_termios
;
1291 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1292 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1293 mutex_unlock(&tty
->termios_mutex
);
1297 * do_tty_hangup - actual handler for hangup events
1300 * This can be called by the "eventd" kernel thread. That is process
1301 * synchronous but doesn't hold any locks, so we need to make sure we
1302 * have the appropriate locks for what we're doing.
1304 * The hangup event clears any pending redirections onto the hung up
1305 * device. It ensures future writes will error and it does the needed
1306 * line discipline hangup and signal delivery. The tty object itself
1311 * redirect lock for undoing redirection
1312 * file list lock for manipulating list of ttys
1313 * tty_ldisc_lock from called functions
1314 * termios_mutex resetting termios data
1315 * tasklist_lock to walk task list for hangup event
1316 * ->siglock to protect ->signal/->sighand
1318 static void do_tty_hangup(struct work_struct
*work
)
1320 struct tty_struct
*tty
=
1321 container_of(work
, struct tty_struct
, hangup_work
);
1322 struct file
* cons_filp
= NULL
;
1323 struct file
*filp
, *f
= NULL
;
1324 struct task_struct
*p
;
1325 struct tty_ldisc
*ld
;
1326 int closecount
= 0, n
;
1331 /* inuse_filps is protected by the single kernel lock */
1334 spin_lock(&redirect_lock
);
1335 if (redirect
&& redirect
->private_data
== tty
) {
1339 spin_unlock(&redirect_lock
);
1341 check_tty_count(tty
, "do_tty_hangup");
1343 /* This breaks for file handles being sent over AF_UNIX sockets ? */
1344 list_for_each_entry(filp
, &tty
->tty_files
, f_u
.fu_list
) {
1345 if (filp
->f_op
->write
== redirected_tty_write
)
1347 if (filp
->f_op
->write
!= tty_write
)
1350 tty_fasync(-1, filp
, 0); /* can't block */
1351 filp
->f_op
= &hung_up_tty_fops
;
1355 /* FIXME! What are the locking issues here? This may me overdoing things..
1356 * this question is especially important now that we've removed the irqlock. */
1358 ld
= tty_ldisc_ref(tty
);
1359 if(ld
!= NULL
) /* We may have no line discipline at this point */
1361 if (ld
->flush_buffer
)
1362 ld
->flush_buffer(tty
);
1363 if (tty
->driver
->flush_buffer
)
1364 tty
->driver
->flush_buffer(tty
);
1365 if ((test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) &&
1367 ld
->write_wakeup(tty
);
1372 /* FIXME: Once we trust the LDISC code better we can wait here for
1373 ldisc completion and fix the driver call race */
1375 wake_up_interruptible(&tty
->write_wait
);
1376 wake_up_interruptible(&tty
->read_wait
);
1379 * Shutdown the current line discipline, and reset it to
1382 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
)
1383 tty_reset_termios(tty
);
1385 /* Defer ldisc switch */
1386 /* tty_deferred_ldisc_switch(N_TTY);
1388 This should get done automatically when the port closes and
1389 tty_release is called */
1391 read_lock(&tasklist_lock
);
1393 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
1394 spin_lock_irq(&p
->sighand
->siglock
);
1395 if (p
->signal
->tty
== tty
)
1396 p
->signal
->tty
= NULL
;
1397 if (!p
->signal
->leader
) {
1398 spin_unlock_irq(&p
->sighand
->siglock
);
1401 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
1402 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
1403 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
1405 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
1406 spin_unlock_irq(&p
->sighand
->siglock
);
1407 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
1409 read_unlock(&tasklist_lock
);
1412 put_pid(tty
->session
);
1414 tty
->session
= NULL
;
1416 tty
->ctrl_status
= 0;
1418 * If one of the devices matches a console pointer, we
1419 * cannot just call hangup() because that will cause
1420 * tty->count and state->count to go out of sync.
1421 * So we just call close() the right number of times.
1424 if (tty
->driver
->close
)
1425 for (n
= 0; n
< closecount
; n
++)
1426 tty
->driver
->close(tty
, cons_filp
);
1427 } else if (tty
->driver
->hangup
)
1428 (tty
->driver
->hangup
)(tty
);
1430 /* We don't want to have driver/ldisc interactions beyond
1431 the ones we did here. The driver layer expects no
1432 calls after ->hangup() from the ldisc side. However we
1433 can't yet guarantee all that */
1435 set_bit(TTY_HUPPED
, &tty
->flags
);
1437 tty_ldisc_enable(tty
);
1438 tty_ldisc_deref(ld
);
1446 * tty_hangup - trigger a hangup event
1447 * @tty: tty to hangup
1449 * A carrier loss (virtual or otherwise) has occurred on this like
1450 * schedule a hangup sequence to run after this event.
1453 void tty_hangup(struct tty_struct
* tty
)
1455 #ifdef TTY_DEBUG_HANGUP
1458 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
1460 schedule_work(&tty
->hangup_work
);
1463 EXPORT_SYMBOL(tty_hangup
);
1466 * tty_vhangup - process vhangup
1467 * @tty: tty to hangup
1469 * The user has asked via system call for the terminal to be hung up.
1470 * We do this synchronously so that when the syscall returns the process
1471 * is complete. That guarantee is neccessary for security reasons.
1474 void tty_vhangup(struct tty_struct
* tty
)
1476 #ifdef TTY_DEBUG_HANGUP
1479 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
1481 do_tty_hangup(&tty
->hangup_work
);
1483 EXPORT_SYMBOL(tty_vhangup
);
1486 * tty_hung_up_p - was tty hung up
1487 * @filp: file pointer of tty
1489 * Return true if the tty has been subject to a vhangup or a carrier
1493 int tty_hung_up_p(struct file
* filp
)
1495 return (filp
->f_op
== &hung_up_tty_fops
);
1498 EXPORT_SYMBOL(tty_hung_up_p
);
1500 static void session_clear_tty(struct pid
*session
)
1502 struct task_struct
*p
;
1503 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
1505 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
1509 * disassociate_ctty - disconnect controlling tty
1510 * @on_exit: true if exiting so need to "hang up" the session
1512 * This function is typically called only by the session leader, when
1513 * it wants to disassociate itself from its controlling tty.
1515 * It performs the following functions:
1516 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
1517 * (2) Clears the tty from being controlling the session
1518 * (3) Clears the controlling tty for all processes in the
1521 * The argument on_exit is set to 1 if called when a process is
1522 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
1525 * BKL is taken for hysterical raisins
1526 * tty_mutex is taken to protect tty
1527 * ->siglock is taken to protect ->signal/->sighand
1528 * tasklist_lock is taken to walk process list for sessions
1529 * ->siglock is taken to protect ->signal/->sighand
1532 void disassociate_ctty(int on_exit
)
1534 struct tty_struct
*tty
;
1535 struct pid
*tty_pgrp
= NULL
;
1539 mutex_lock(&tty_mutex
);
1540 tty
= get_current_tty();
1542 tty_pgrp
= get_pid(tty
->pgrp
);
1543 mutex_unlock(&tty_mutex
);
1544 /* XXX: here we race, there is nothing protecting tty */
1545 if (on_exit
&& tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
1547 } else if (on_exit
) {
1548 struct pid
*old_pgrp
;
1549 spin_lock_irq(¤t
->sighand
->siglock
);
1550 old_pgrp
= current
->signal
->tty_old_pgrp
;
1551 current
->signal
->tty_old_pgrp
= NULL
;
1552 spin_unlock_irq(¤t
->sighand
->siglock
);
1554 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
1555 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
1558 mutex_unlock(&tty_mutex
);
1563 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
1565 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
1569 spin_lock_irq(¤t
->sighand
->siglock
);
1570 put_pid(current
->signal
->tty_old_pgrp
);
1571 current
->signal
->tty_old_pgrp
= NULL
;
1572 spin_unlock_irq(¤t
->sighand
->siglock
);
1574 mutex_lock(&tty_mutex
);
1575 /* It is possible that do_tty_hangup has free'd this tty */
1576 tty
= get_current_tty();
1578 put_pid(tty
->session
);
1580 tty
->session
= NULL
;
1583 #ifdef TTY_DEBUG_HANGUP
1584 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
1588 mutex_unlock(&tty_mutex
);
1590 /* Now clear signal->tty under the lock */
1591 read_lock(&tasklist_lock
);
1592 session_clear_tty(task_session(current
));
1593 read_unlock(&tasklist_lock
);
1599 * no_tty - Ensure the current process does not have a controlling tty
1603 struct task_struct
*tsk
= current
;
1604 if (tsk
->signal
->leader
)
1605 disassociate_ctty(0);
1606 proc_clear_tty(tsk
);
1611 * stop_tty - propagate flow control
1614 * Perform flow control to the driver. For PTY/TTY pairs we
1615 * must also propagate the TIOCKPKT status. May be called
1616 * on an already stopped device and will not re-call the driver
1619 * This functionality is used by both the line disciplines for
1620 * halting incoming flow and by the driver. It may therefore be
1621 * called from any context, may be under the tty atomic_write_lock
1625 * Broken. Relies on BKL which is unsafe here.
1628 void stop_tty(struct tty_struct
*tty
)
1633 if (tty
->link
&& tty
->link
->packet
) {
1634 tty
->ctrl_status
&= ~TIOCPKT_START
;
1635 tty
->ctrl_status
|= TIOCPKT_STOP
;
1636 wake_up_interruptible(&tty
->link
->read_wait
);
1638 if (tty
->driver
->stop
)
1639 (tty
->driver
->stop
)(tty
);
1642 EXPORT_SYMBOL(stop_tty
);
1645 * start_tty - propagate flow control
1646 * @tty: tty to start
1648 * Start a tty that has been stopped if at all possible. Perform
1649 * any neccessary wakeups and propagate the TIOCPKT status. If this
1650 * is the tty was previous stopped and is being started then the
1651 * driver start method is invoked and the line discipline woken.
1654 * Broken. Relies on BKL which is unsafe here.
1657 void start_tty(struct tty_struct
*tty
)
1659 if (!tty
->stopped
|| tty
->flow_stopped
)
1662 if (tty
->link
&& tty
->link
->packet
) {
1663 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
1664 tty
->ctrl_status
|= TIOCPKT_START
;
1665 wake_up_interruptible(&tty
->link
->read_wait
);
1667 if (tty
->driver
->start
)
1668 (tty
->driver
->start
)(tty
);
1670 /* If we have a running line discipline it may need kicking */
1674 EXPORT_SYMBOL(start_tty
);
1677 * tty_read - read method for tty device files
1678 * @file: pointer to tty file
1680 * @count: size of user buffer
1683 * Perform the read system call function on this terminal device. Checks
1684 * for hung up devices before calling the line discipline method.
1687 * Locks the line discipline internally while needed
1688 * For historical reasons the line discipline read method is
1689 * invoked under the BKL. This will go away in time so do not rely on it
1690 * in new code. Multiple read calls may be outstanding in parallel.
1693 static ssize_t
tty_read(struct file
* file
, char __user
* buf
, size_t count
,
1697 struct tty_struct
* tty
;
1698 struct inode
*inode
;
1699 struct tty_ldisc
*ld
;
1701 tty
= (struct tty_struct
*)file
->private_data
;
1702 inode
= file
->f_path
.dentry
->d_inode
;
1703 if (tty_paranoia_check(tty
, inode
, "tty_read"))
1705 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1708 /* We want to wait for the line discipline to sort out in this
1710 ld
= tty_ldisc_ref_wait(tty
);
1713 i
= (ld
->read
)(tty
,file
,buf
,count
);
1716 tty_ldisc_deref(ld
);
1719 inode
->i_atime
= current_fs_time(inode
->i_sb
);
1724 * Split writes up in sane blocksizes to avoid
1725 * denial-of-service type attacks
1727 static inline ssize_t
do_tty_write(
1728 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1729 struct tty_struct
*tty
,
1731 const char __user
*buf
,
1734 ssize_t ret
= 0, written
= 0;
1737 /* FIXME: O_NDELAY ... */
1738 if (mutex_lock_interruptible(&tty
->atomic_write_lock
)) {
1739 return -ERESTARTSYS
;
1743 * We chunk up writes into a temporary buffer. This
1744 * simplifies low-level drivers immensely, since they
1745 * don't have locking issues and user mode accesses.
1747 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1750 * The default chunk-size is 2kB, because the NTTY
1751 * layer has problems with bigger chunks. It will
1752 * claim to be able to handle more characters than
1755 * FIXME: This can probably go away now except that 64K chunks
1756 * are too likely to fail unless switched to vmalloc...
1759 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1764 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1765 if (tty
->write_cnt
< chunk
) {
1771 buf
= kmalloc(chunk
, GFP_KERNEL
);
1773 mutex_unlock(&tty
->atomic_write_lock
);
1776 kfree(tty
->write_buf
);
1777 tty
->write_cnt
= chunk
;
1778 tty
->write_buf
= buf
;
1781 /* Do the write .. */
1783 size_t size
= count
;
1787 if (copy_from_user(tty
->write_buf
, buf
, size
))
1790 ret
= write(tty
, file
, tty
->write_buf
, size
);
1800 if (signal_pending(current
))
1805 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1806 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1809 mutex_unlock(&tty
->atomic_write_lock
);
1815 * tty_write - write method for tty device file
1816 * @file: tty file pointer
1817 * @buf: user data to write
1818 * @count: bytes to write
1821 * Write data to a tty device via the line discipline.
1824 * Locks the line discipline as required
1825 * Writes to the tty driver are serialized by the atomic_write_lock
1826 * and are then processed in chunks to the device. The line discipline
1827 * write method will not be involked in parallel for each device
1828 * The line discipline write method is called under the big
1829 * kernel lock for historical reasons. New code should not rely on this.
1832 static ssize_t
tty_write(struct file
* file
, const char __user
* buf
, size_t count
,
1835 struct tty_struct
* tty
;
1836 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1838 struct tty_ldisc
*ld
;
1840 tty
= (struct tty_struct
*)file
->private_data
;
1841 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1843 if (!tty
|| !tty
->driver
->write
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1846 ld
= tty_ldisc_ref_wait(tty
);
1850 ret
= do_tty_write(ld
->write
, tty
, file
, buf
, count
);
1851 tty_ldisc_deref(ld
);
1855 ssize_t
redirected_tty_write(struct file
* file
, const char __user
* buf
, size_t count
,
1858 struct file
*p
= NULL
;
1860 spin_lock(&redirect_lock
);
1865 spin_unlock(&redirect_lock
);
1869 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1874 return tty_write(file
, buf
, count
, ppos
);
1877 static char ptychar
[] = "pqrstuvwxyzabcde";
1880 * pty_line_name - generate name for a pty
1881 * @driver: the tty driver in use
1882 * @index: the minor number
1883 * @p: output buffer of at least 6 bytes
1885 * Generate a name from a driver reference and write it to the output
1890 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1892 int i
= index
+ driver
->name_base
;
1893 /* ->name is initialized to "ttyp", but "tty" is expected */
1894 sprintf(p
, "%s%c%x",
1895 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1896 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1900 * pty_line_name - generate name for a tty
1901 * @driver: the tty driver in use
1902 * @index: the minor number
1903 * @p: output buffer of at least 7 bytes
1905 * Generate a name from a driver reference and write it to the output
1910 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1912 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1916 * init_dev - initialise a tty device
1917 * @driver: tty driver we are opening a device on
1918 * @idx: device index
1919 * @tty: returned tty structure
1921 * Prepare a tty device. This may not be a "new" clean device but
1922 * could also be an active device. The pty drivers require special
1923 * handling because of this.
1926 * The function is called under the tty_mutex, which
1927 * protects us from the tty struct or driver itself going away.
1929 * On exit the tty device has the line discipline attached and
1930 * a reference count of 1. If a pair was created for pty/tty use
1931 * and the other was a pty master then it too has a reference count of 1.
1933 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1934 * failed open. The new code protects the open with a mutex, so it's
1935 * really quite straightforward. The mutex locking can probably be
1936 * relaxed for the (most common) case of reopening a tty.
1939 static int init_dev(struct tty_driver
*driver
, int idx
,
1940 struct tty_struct
**ret_tty
)
1942 struct tty_struct
*tty
, *o_tty
;
1943 struct ktermios
*tp
, **tp_loc
, *o_tp
, **o_tp_loc
;
1944 struct ktermios
*ltp
, **ltp_loc
, *o_ltp
, **o_ltp_loc
;
1947 /* check whether we're reopening an existing tty */
1948 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1949 tty
= devpts_get_tty(idx
);
1951 * If we don't have a tty here on a slave open, it's because
1952 * the master already started the close process and there's
1953 * no relation between devpts file and tty anymore.
1955 if (!tty
&& driver
->subtype
== PTY_TYPE_SLAVE
) {
1960 * It's safe from now on because init_dev() is called with
1961 * tty_mutex held and release_dev() won't change tty->count
1962 * or tty->flags without having to grab tty_mutex
1964 if (tty
&& driver
->subtype
== PTY_TYPE_MASTER
)
1967 tty
= driver
->ttys
[idx
];
1969 if (tty
) goto fast_track
;
1972 * First time open is complex, especially for PTY devices.
1973 * This code guarantees that either everything succeeds and the
1974 * TTY is ready for operation, or else the table slots are vacated
1975 * and the allocated memory released. (Except that the termios
1976 * and locked termios may be retained.)
1979 if (!try_module_get(driver
->owner
)) {
1988 tty
= alloc_tty_struct();
1991 initialize_tty_struct(tty
);
1992 tty
->driver
= driver
;
1994 tty_line_name(driver
, idx
, tty
->name
);
1996 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
1997 tp_loc
= &tty
->termios
;
1998 ltp_loc
= &tty
->termios_locked
;
2000 tp_loc
= &driver
->termios
[idx
];
2001 ltp_loc
= &driver
->termios_locked
[idx
];
2005 tp
= (struct ktermios
*) kmalloc(sizeof(struct ktermios
),
2009 *tp
= driver
->init_termios
;
2013 ltp
= (struct ktermios
*) kmalloc(sizeof(struct ktermios
),
2017 memset(ltp
, 0, sizeof(struct ktermios
));
2020 if (driver
->type
== TTY_DRIVER_TYPE_PTY
) {
2021 o_tty
= alloc_tty_struct();
2024 initialize_tty_struct(o_tty
);
2025 o_tty
->driver
= driver
->other
;
2027 tty_line_name(driver
->other
, idx
, o_tty
->name
);
2029 if (driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) {
2030 o_tp_loc
= &o_tty
->termios
;
2031 o_ltp_loc
= &o_tty
->termios_locked
;
2033 o_tp_loc
= &driver
->other
->termios
[idx
];
2034 o_ltp_loc
= &driver
->other
->termios_locked
[idx
];
2038 o_tp
= (struct ktermios
*)
2039 kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2042 *o_tp
= driver
->other
->init_termios
;
2046 o_ltp
= (struct ktermios
*)
2047 kmalloc(sizeof(struct ktermios
), GFP_KERNEL
);
2050 memset(o_ltp
, 0, sizeof(struct ktermios
));
2054 * Everything allocated ... set up the o_tty structure.
2056 if (!(driver
->other
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2057 driver
->other
->ttys
[idx
] = o_tty
;
2063 o_tty
->termios
= *o_tp_loc
;
2064 o_tty
->termios_locked
= *o_ltp_loc
;
2065 driver
->other
->refcount
++;
2066 if (driver
->subtype
== PTY_TYPE_MASTER
)
2069 /* Establish the links in both directions */
2075 * All structures have been allocated, so now we install them.
2076 * Failures after this point use release_tty to clean up, so
2077 * there's no need to null out the local pointers.
2079 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2080 driver
->ttys
[idx
] = tty
;
2087 tty
->termios
= *tp_loc
;
2088 tty
->termios_locked
= *ltp_loc
;
2089 /* Compatibility until drivers always set this */
2090 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
2091 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
2096 * Structures all installed ... call the ldisc open routines.
2097 * If we fail here just call release_tty to clean up. No need
2098 * to decrement the use counts, as release_tty doesn't care.
2101 if (tty
->ldisc
.open
) {
2102 retval
= (tty
->ldisc
.open
)(tty
);
2104 goto release_mem_out
;
2106 if (o_tty
&& o_tty
->ldisc
.open
) {
2107 retval
= (o_tty
->ldisc
.open
)(o_tty
);
2109 if (tty
->ldisc
.close
)
2110 (tty
->ldisc
.close
)(tty
);
2111 goto release_mem_out
;
2113 tty_ldisc_enable(o_tty
);
2115 tty_ldisc_enable(tty
);
2119 * This fast open can be used if the tty is already open.
2120 * No memory is allocated, and the only failures are from
2121 * attempting to open a closing tty or attempting multiple
2122 * opens on a pty master.
2125 if (test_bit(TTY_CLOSING
, &tty
->flags
)) {
2129 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2130 driver
->subtype
== PTY_TYPE_MASTER
) {
2132 * special case for PTY masters: only one open permitted,
2133 * and the slave side open count is incremented as well.
2142 tty
->driver
= driver
; /* N.B. why do this every time?? */
2145 if(!test_bit(TTY_LDISC
, &tty
->flags
))
2146 printk(KERN_ERR
"init_dev but no ldisc\n");
2150 /* All paths come through here to release the mutex */
2154 /* Release locally allocated memory ... nothing placed in slots */
2158 free_tty_struct(o_tty
);
2161 free_tty_struct(tty
);
2164 module_put(driver
->owner
);
2168 /* call the tty release_tty routine to clean out this slot */
2170 if (printk_ratelimit())
2171 printk(KERN_INFO
"init_dev: ldisc open failed, "
2172 "clearing slot %d\n", idx
);
2173 release_tty(tty
, idx
);
2178 * release_one_tty - release tty structure memory
2180 * Releases memory associated with a tty structure, and clears out the
2181 * driver table slots. This function is called when a device is no longer
2182 * in use. It also gets called when setup of a device fails.
2185 * tty_mutex - sometimes only
2186 * takes the file list lock internally when working on the list
2187 * of ttys that the driver keeps.
2188 * FIXME: should we require tty_mutex is held here ??
2190 static void release_one_tty(struct tty_struct
*tty
, int idx
)
2192 int devpts
= tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
;
2193 struct ktermios
*tp
;
2196 tty
->driver
->ttys
[idx
] = NULL
;
2198 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
2201 tty
->driver
->termios
[idx
] = NULL
;
2204 tp
= tty
->termios_locked
;
2206 tty
->driver
->termios_locked
[idx
] = NULL
;
2212 tty
->driver
->refcount
--;
2215 list_del_init(&tty
->tty_files
);
2218 free_tty_struct(tty
);
2222 * release_tty - release tty structure memory
2224 * Release both @tty and a possible linked partner (think pty pair),
2225 * and decrement the refcount of the backing module.
2228 * tty_mutex - sometimes only
2229 * takes the file list lock internally when working on the list
2230 * of ttys that the driver keeps.
2231 * FIXME: should we require tty_mutex is held here ??
2233 static void release_tty(struct tty_struct
*tty
, int idx
)
2235 struct tty_driver
*driver
= tty
->driver
;
2238 release_one_tty(tty
->link
, idx
);
2239 release_one_tty(tty
, idx
);
2240 module_put(driver
->owner
);
2244 * Even releasing the tty structures is a tricky business.. We have
2245 * to be very careful that the structures are all released at the
2246 * same time, as interrupts might otherwise get the wrong pointers.
2248 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
2249 * lead to double frees or releasing memory still in use.
2251 static void release_dev(struct file
* filp
)
2253 struct tty_struct
*tty
, *o_tty
;
2254 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
2258 unsigned long flags
;
2260 tty
= (struct tty_struct
*)filp
->private_data
;
2261 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "release_dev"))
2264 check_tty_count(tty
, "release_dev");
2266 tty_fasync(-1, filp
, 0);
2269 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2270 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
2271 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
2274 #ifdef TTY_PARANOIA_CHECK
2275 if (idx
< 0 || idx
>= tty
->driver
->num
) {
2276 printk(KERN_DEBUG
"release_dev: bad idx when trying to "
2277 "free (%s)\n", tty
->name
);
2280 if (!(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2281 if (tty
!= tty
->driver
->ttys
[idx
]) {
2282 printk(KERN_DEBUG
"release_dev: driver.table[%d] not tty "
2283 "for (%s)\n", idx
, tty
->name
);
2286 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
2287 printk(KERN_DEBUG
"release_dev: driver.termios[%d] not termios "
2292 if (tty
->termios_locked
!= tty
->driver
->termios_locked
[idx
]) {
2293 printk(KERN_DEBUG
"release_dev: driver.termios_locked[%d] not "
2294 "termios_locked for (%s)\n",
2301 #ifdef TTY_DEBUG_HANGUP
2302 printk(KERN_DEBUG
"release_dev of %s (tty count=%d)...",
2303 tty_name(tty
, buf
), tty
->count
);
2306 #ifdef TTY_PARANOIA_CHECK
2307 if (tty
->driver
->other
&&
2308 !(tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)) {
2309 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
2310 printk(KERN_DEBUG
"release_dev: other->table[%d] "
2311 "not o_tty for (%s)\n",
2315 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
2316 printk(KERN_DEBUG
"release_dev: other->termios[%d] "
2317 "not o_termios for (%s)\n",
2321 if (o_tty
->termios_locked
!=
2322 tty
->driver
->other
->termios_locked
[idx
]) {
2323 printk(KERN_DEBUG
"release_dev: other->termios_locked["
2324 "%d] not o_termios_locked for (%s)\n",
2328 if (o_tty
->link
!= tty
) {
2329 printk(KERN_DEBUG
"release_dev: bad pty pointers\n");
2334 if (tty
->driver
->close
)
2335 tty
->driver
->close(tty
, filp
);
2338 * Sanity check: if tty->count is going to zero, there shouldn't be
2339 * any waiters on tty->read_wait or tty->write_wait. We test the
2340 * wait queues and kick everyone out _before_ actually starting to
2341 * close. This ensures that we won't block while releasing the tty
2344 * The test for the o_tty closing is necessary, since the master and
2345 * slave sides may close in any order. If the slave side closes out
2346 * first, its count will be one, since the master side holds an open.
2347 * Thus this test wouldn't be triggered at the time the slave closes,
2350 * Note that it's possible for the tty to be opened again while we're
2351 * flushing out waiters. By recalculating the closing flags before
2352 * each iteration we avoid any problems.
2355 /* Guard against races with tty->count changes elsewhere and
2356 opens on /dev/tty */
2358 mutex_lock(&tty_mutex
);
2359 tty_closing
= tty
->count
<= 1;
2360 o_tty_closing
= o_tty
&&
2361 (o_tty
->count
<= (pty_master
? 1 : 0));
2365 if (waitqueue_active(&tty
->read_wait
)) {
2366 wake_up(&tty
->read_wait
);
2369 if (waitqueue_active(&tty
->write_wait
)) {
2370 wake_up(&tty
->write_wait
);
2374 if (o_tty_closing
) {
2375 if (waitqueue_active(&o_tty
->read_wait
)) {
2376 wake_up(&o_tty
->read_wait
);
2379 if (waitqueue_active(&o_tty
->write_wait
)) {
2380 wake_up(&o_tty
->write_wait
);
2387 printk(KERN_WARNING
"release_dev: %s: read/write wait queue "
2388 "active!\n", tty_name(tty
, buf
));
2389 mutex_unlock(&tty_mutex
);
2394 * The closing flags are now consistent with the open counts on
2395 * both sides, and we've completed the last operation that could
2396 * block, so it's safe to proceed with closing.
2399 if (--o_tty
->count
< 0) {
2400 printk(KERN_WARNING
"release_dev: bad pty slave count "
2402 o_tty
->count
, tty_name(o_tty
, buf
));
2406 if (--tty
->count
< 0) {
2407 printk(KERN_WARNING
"release_dev: bad tty->count (%d) for %s\n",
2408 tty
->count
, tty_name(tty
, buf
));
2413 * We've decremented tty->count, so we need to remove this file
2414 * descriptor off the tty->tty_files list; this serves two
2416 * - check_tty_count sees the correct number of file descriptors
2417 * associated with this tty.
2418 * - do_tty_hangup no longer sees this file descriptor as
2419 * something that needs to be handled for hangups.
2422 filp
->private_data
= NULL
;
2425 * Perform some housekeeping before deciding whether to return.
2427 * Set the TTY_CLOSING flag if this was the last open. In the
2428 * case of a pty we may have to wait around for the other side
2429 * to close, and TTY_CLOSING makes sure we can't be reopened.
2432 set_bit(TTY_CLOSING
, &tty
->flags
);
2434 set_bit(TTY_CLOSING
, &o_tty
->flags
);
2437 * If _either_ side is closing, make sure there aren't any
2438 * processes that still think tty or o_tty is their controlling
2441 if (tty_closing
|| o_tty_closing
) {
2442 read_lock(&tasklist_lock
);
2443 session_clear_tty(tty
->session
);
2445 session_clear_tty(o_tty
->session
);
2446 read_unlock(&tasklist_lock
);
2449 mutex_unlock(&tty_mutex
);
2451 /* check whether both sides are closing ... */
2452 if (!tty_closing
|| (o_tty
&& !o_tty_closing
))
2455 #ifdef TTY_DEBUG_HANGUP
2456 printk(KERN_DEBUG
"freeing tty structure...");
2459 * Prevent flush_to_ldisc() from rescheduling the work for later. Then
2460 * kill any delayed work. As this is the final close it does not
2461 * race with the set_ldisc code path.
2463 clear_bit(TTY_LDISC
, &tty
->flags
);
2464 cancel_delayed_work(&tty
->buf
.work
);
2467 * Wait for ->hangup_work and ->buf.work handlers to terminate
2470 flush_scheduled_work();
2473 * Wait for any short term users (we know they are just driver
2474 * side waiters as the file is closing so user count on the file
2477 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2478 while(tty
->ldisc
.refcount
)
2480 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2481 wait_event(tty_ldisc_wait
, tty
->ldisc
.refcount
== 0);
2482 spin_lock_irqsave(&tty_ldisc_lock
, flags
);
2484 spin_unlock_irqrestore(&tty_ldisc_lock
, flags
);
2486 * Shutdown the current line discipline, and reset it to N_TTY.
2487 * N.B. why reset ldisc when we're releasing the memory??
2489 * FIXME: this MUST get fixed for the new reflocking
2491 if (tty
->ldisc
.close
)
2492 (tty
->ldisc
.close
)(tty
);
2493 tty_ldisc_put(tty
->ldisc
.num
);
2496 * Switch the line discipline back
2498 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
2499 tty_set_termios_ldisc(tty
,N_TTY
);
2501 /* FIXME: could o_tty be in setldisc here ? */
2502 clear_bit(TTY_LDISC
, &o_tty
->flags
);
2503 if (o_tty
->ldisc
.close
)
2504 (o_tty
->ldisc
.close
)(o_tty
);
2505 tty_ldisc_put(o_tty
->ldisc
.num
);
2506 tty_ldisc_assign(o_tty
, tty_ldisc_get(N_TTY
));
2507 tty_set_termios_ldisc(o_tty
,N_TTY
);
2510 * The release_tty function takes care of the details of clearing
2511 * the slots and preserving the termios structure.
2513 release_tty(tty
, idx
);
2515 #ifdef CONFIG_UNIX98_PTYS
2516 /* Make this pty number available for reallocation */
2518 down(&allocated_ptys_lock
);
2519 idr_remove(&allocated_ptys
, idx
);
2520 up(&allocated_ptys_lock
);
2527 * tty_open - open a tty device
2528 * @inode: inode of device file
2529 * @filp: file pointer to tty
2531 * tty_open and tty_release keep up the tty count that contains the
2532 * number of opens done on a tty. We cannot use the inode-count, as
2533 * different inodes might point to the same tty.
2535 * Open-counting is needed for pty masters, as well as for keeping
2536 * track of serial lines: DTR is dropped when the last close happens.
2537 * (This is not done solely through tty->count, now. - Ted 1/27/92)
2539 * The termios state of a pty is reset on first open so that
2540 * settings don't persist across reuse.
2542 * Locking: tty_mutex protects tty, get_tty_driver and init_dev work.
2543 * tty->count should protect the rest.
2544 * ->siglock protects ->signal/->sighand
2547 static int tty_open(struct inode
* inode
, struct file
* filp
)
2549 struct tty_struct
*tty
;
2551 struct tty_driver
*driver
;
2553 dev_t device
= inode
->i_rdev
;
2554 unsigned short saved_flags
= filp
->f_flags
;
2556 nonseekable_open(inode
, filp
);
2559 noctty
= filp
->f_flags
& O_NOCTTY
;
2563 mutex_lock(&tty_mutex
);
2565 if (device
== MKDEV(TTYAUX_MAJOR
,0)) {
2566 tty
= get_current_tty();
2568 mutex_unlock(&tty_mutex
);
2571 driver
= tty
->driver
;
2573 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
2578 if (device
== MKDEV(TTY_MAJOR
,0)) {
2579 extern struct tty_driver
*console_driver
;
2580 driver
= console_driver
;
2586 if (device
== MKDEV(TTYAUX_MAJOR
,1)) {
2587 driver
= console_device(&index
);
2589 /* Don't let /dev/console block */
2590 filp
->f_flags
|= O_NONBLOCK
;
2594 mutex_unlock(&tty_mutex
);
2598 driver
= get_tty_driver(device
, &index
);
2600 mutex_unlock(&tty_mutex
);
2604 retval
= init_dev(driver
, index
, &tty
);
2605 mutex_unlock(&tty_mutex
);
2609 filp
->private_data
= tty
;
2610 file_move(filp
, &tty
->tty_files
);
2611 check_tty_count(tty
, "tty_open");
2612 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2613 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2615 #ifdef TTY_DEBUG_HANGUP
2616 printk(KERN_DEBUG
"opening %s...", tty
->name
);
2619 if (tty
->driver
->open
)
2620 retval
= tty
->driver
->open(tty
, filp
);
2624 filp
->f_flags
= saved_flags
;
2626 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) && !capable(CAP_SYS_ADMIN
))
2630 #ifdef TTY_DEBUG_HANGUP
2631 printk(KERN_DEBUG
"error %d in opening %s...", retval
,
2635 if (retval
!= -ERESTARTSYS
)
2637 if (signal_pending(current
))
2641 * Need to reset f_op in case a hangup happened.
2643 if (filp
->f_op
== &hung_up_tty_fops
)
2644 filp
->f_op
= &tty_fops
;
2648 mutex_lock(&tty_mutex
);
2649 spin_lock_irq(¤t
->sighand
->siglock
);
2651 current
->signal
->leader
&&
2652 !current
->signal
->tty
&&
2653 tty
->session
== NULL
)
2654 __proc_set_tty(current
, tty
);
2655 spin_unlock_irq(¤t
->sighand
->siglock
);
2656 mutex_unlock(&tty_mutex
);
2660 #ifdef CONFIG_UNIX98_PTYS
2662 * ptmx_open - open a unix 98 pty master
2663 * @inode: inode of device file
2664 * @filp: file pointer to tty
2666 * Allocate a unix98 pty master device from the ptmx driver.
2668 * Locking: tty_mutex protects theinit_dev work. tty->count should
2670 * allocated_ptys_lock handles the list of free pty numbers
2673 static int ptmx_open(struct inode
* inode
, struct file
* filp
)
2675 struct tty_struct
*tty
;
2680 nonseekable_open(inode
, filp
);
2682 /* find a device that is not in use. */
2683 down(&allocated_ptys_lock
);
2684 if (!idr_pre_get(&allocated_ptys
, GFP_KERNEL
)) {
2685 up(&allocated_ptys_lock
);
2688 idr_ret
= idr_get_new(&allocated_ptys
, NULL
, &index
);
2690 up(&allocated_ptys_lock
);
2691 if (idr_ret
== -EAGAIN
)
2695 if (index
>= pty_limit
) {
2696 idr_remove(&allocated_ptys
, index
);
2697 up(&allocated_ptys_lock
);
2700 up(&allocated_ptys_lock
);
2702 mutex_lock(&tty_mutex
);
2703 retval
= init_dev(ptm_driver
, index
, &tty
);
2704 mutex_unlock(&tty_mutex
);
2709 set_bit(TTY_PTY_LOCK
, &tty
->flags
); /* LOCK THE SLAVE */
2710 filp
->private_data
= tty
;
2711 file_move(filp
, &tty
->tty_files
);
2714 if (devpts_pty_new(tty
->link
))
2717 check_tty_count(tty
, "tty_open");
2718 retval
= ptm_driver
->open(tty
, filp
);
2725 down(&allocated_ptys_lock
);
2726 idr_remove(&allocated_ptys
, index
);
2727 up(&allocated_ptys_lock
);
2733 * tty_release - vfs callback for close
2734 * @inode: inode of tty
2735 * @filp: file pointer for handle to tty
2737 * Called the last time each file handle is closed that references
2738 * this tty. There may however be several such references.
2741 * Takes bkl. See release_dev
2744 static int tty_release(struct inode
* inode
, struct file
* filp
)
2753 * tty_poll - check tty status
2754 * @filp: file being polled
2755 * @wait: poll wait structures to update
2757 * Call the line discipline polling method to obtain the poll
2758 * status of the device.
2760 * Locking: locks called line discipline but ldisc poll method
2761 * may be re-entered freely by other callers.
2764 static unsigned int tty_poll(struct file
* filp
, poll_table
* wait
)
2766 struct tty_struct
* tty
;
2767 struct tty_ldisc
*ld
;
2770 tty
= (struct tty_struct
*)filp
->private_data
;
2771 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2774 ld
= tty_ldisc_ref_wait(tty
);
2776 ret
= (ld
->poll
)(tty
, filp
, wait
);
2777 tty_ldisc_deref(ld
);
2781 static int tty_fasync(int fd
, struct file
* filp
, int on
)
2783 struct tty_struct
* tty
;
2786 tty
= (struct tty_struct
*)filp
->private_data
;
2787 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2790 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2797 if (!waitqueue_active(&tty
->read_wait
))
2798 tty
->minimum_to_wake
= 1;
2801 type
= PIDTYPE_PGID
;
2803 pid
= task_pid(current
);
2806 retval
= __f_setown(filp
, pid
, type
, 0);
2810 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2811 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2817 * tiocsti - fake input character
2818 * @tty: tty to fake input into
2819 * @p: pointer to character
2821 * Fake input to a tty device. Does the neccessary locking and
2824 * FIXME: does not honour flow control ??
2827 * Called functions take tty_ldisc_lock
2828 * current->signal->tty check is safe without locks
2830 * FIXME: may race normal receive processing
2833 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2836 struct tty_ldisc
*ld
;
2838 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2840 if (get_user(ch
, p
))
2842 ld
= tty_ldisc_ref_wait(tty
);
2843 ld
->receive_buf(tty
, &ch
, &mbz
, 1);
2844 tty_ldisc_deref(ld
);
2849 * tiocgwinsz - implement window query ioctl
2851 * @arg: user buffer for result
2853 * Copies the kernel idea of the window size into the user buffer.
2855 * Locking: tty->termios_mutex is taken to ensure the winsize data
2859 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
* arg
)
2863 mutex_lock(&tty
->termios_mutex
);
2864 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2865 mutex_unlock(&tty
->termios_mutex
);
2867 return err
? -EFAULT
: 0;
2871 * tiocswinsz - implement window size set ioctl
2873 * @arg: user buffer for result
2875 * Copies the user idea of the window size to the kernel. Traditionally
2876 * this is just advisory information but for the Linux console it
2877 * actually has driver level meaning and triggers a VC resize.
2880 * Called function use the console_sem is used to ensure we do
2881 * not try and resize the console twice at once.
2882 * The tty->termios_mutex is used to ensure we don't double
2883 * resize and get confused. Lock order - tty->termios_mutex before
2887 static int tiocswinsz(struct tty_struct
*tty
, struct tty_struct
*real_tty
,
2888 struct winsize __user
* arg
)
2890 struct winsize tmp_ws
;
2892 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2895 mutex_lock(&tty
->termios_mutex
);
2896 if (!memcmp(&tmp_ws
, &tty
->winsize
, sizeof(*arg
)))
2900 if (tty
->driver
->type
== TTY_DRIVER_TYPE_CONSOLE
) {
2901 if (vc_lock_resize(tty
->driver_data
, tmp_ws
.ws_col
,
2903 mutex_unlock(&tty
->termios_mutex
);
2909 kill_pgrp(tty
->pgrp
, SIGWINCH
, 1);
2910 if ((real_tty
->pgrp
!= tty
->pgrp
) && real_tty
->pgrp
)
2911 kill_pgrp(real_tty
->pgrp
, SIGWINCH
, 1);
2912 tty
->winsize
= tmp_ws
;
2913 real_tty
->winsize
= tmp_ws
;
2915 mutex_unlock(&tty
->termios_mutex
);
2920 * tioccons - allow admin to move logical console
2921 * @file: the file to become console
2923 * Allow the adminstrator to move the redirected console device
2925 * Locking: uses redirect_lock to guard the redirect information
2928 static int tioccons(struct file
*file
)
2930 if (!capable(CAP_SYS_ADMIN
))
2932 if (file
->f_op
->write
== redirected_tty_write
) {
2934 spin_lock(&redirect_lock
);
2937 spin_unlock(&redirect_lock
);
2942 spin_lock(&redirect_lock
);
2944 spin_unlock(&redirect_lock
);
2949 spin_unlock(&redirect_lock
);
2954 * fionbio - non blocking ioctl
2955 * @file: file to set blocking value
2956 * @p: user parameter
2958 * Historical tty interfaces had a blocking control ioctl before
2959 * the generic functionality existed. This piece of history is preserved
2960 * in the expected tty API of posix OS's.
2962 * Locking: none, the open fle handle ensures it won't go away.
2965 static int fionbio(struct file
*file
, int __user
*p
)
2969 if (get_user(nonblock
, p
))
2973 file
->f_flags
|= O_NONBLOCK
;
2975 file
->f_flags
&= ~O_NONBLOCK
;
2980 * tiocsctty - set controlling tty
2981 * @tty: tty structure
2982 * @arg: user argument
2984 * This ioctl is used to manage job control. It permits a session
2985 * leader to set this tty as the controlling tty for the session.
2988 * Takes tty_mutex() to protect tty instance
2989 * Takes tasklist_lock internally to walk sessions
2990 * Takes ->siglock() when updating signal->tty
2993 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2996 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2999 mutex_lock(&tty_mutex
);
3001 * The process must be a session leader and
3002 * not have a controlling tty already.
3004 if (!current
->signal
->leader
|| current
->signal
->tty
) {
3011 * This tty is already the controlling
3012 * tty for another session group!
3014 if ((arg
== 1) && capable(CAP_SYS_ADMIN
)) {
3018 read_lock(&tasklist_lock
);
3019 session_clear_tty(tty
->session
);
3020 read_unlock(&tasklist_lock
);
3026 proc_set_tty(current
, tty
);
3028 mutex_unlock(&tty_mutex
);
3033 * tiocgpgrp - get process group
3034 * @tty: tty passed by user
3035 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3038 * Obtain the process group of the tty. If there is no process group
3041 * Locking: none. Reference to current->signal->tty is safe.
3044 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3047 * (tty == real_tty) is a cheap way of
3048 * testing if the tty is NOT a master pty.
3050 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3052 return put_user(pid_nr(real_tty
->pgrp
), p
);
3056 * tiocspgrp - attempt to set process group
3057 * @tty: tty passed by user
3058 * @real_tty: tty side device matching tty passed by user
3061 * Set the process group of the tty to the session passed. Only
3062 * permitted where the tty session is our session.
3067 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3071 int retval
= tty_check_change(real_tty
);
3077 if (!current
->signal
->tty
||
3078 (current
->signal
->tty
!= real_tty
) ||
3079 (real_tty
->session
!= task_session(current
)))
3081 if (get_user(pgrp_nr
, p
))
3086 pgrp
= find_pid(pgrp_nr
);
3091 if (session_of_pgrp(pgrp
) != task_session(current
))
3094 put_pid(real_tty
->pgrp
);
3095 real_tty
->pgrp
= get_pid(pgrp
);
3102 * tiocgsid - get session id
3103 * @tty: tty passed by user
3104 * @real_tty: tty side of the tty pased by the user if a pty else the tty
3105 * @p: pointer to returned session id
3107 * Obtain the session id of the tty. If there is no session
3110 * Locking: none. Reference to current->signal->tty is safe.
3113 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
3116 * (tty == real_tty) is a cheap way of
3117 * testing if the tty is NOT a master pty.
3119 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
3121 if (!real_tty
->session
)
3123 return put_user(pid_nr(real_tty
->session
), p
);
3127 * tiocsetd - set line discipline
3129 * @p: pointer to user data
3131 * Set the line discipline according to user request.
3133 * Locking: see tty_set_ldisc, this function is just a helper
3136 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
3140 if (get_user(ldisc
, p
))
3142 return tty_set_ldisc(tty
, ldisc
);
3146 * send_break - performed time break
3147 * @tty: device to break on
3148 * @duration: timeout in mS
3150 * Perform a timed break on hardware that lacks its own driver level
3151 * timed break functionality.
3154 * atomic_write_lock serializes
3158 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
3160 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
3162 tty
->driver
->break_ctl(tty
, -1);
3163 if (!signal_pending(current
)) {
3164 msleep_interruptible(duration
);
3166 tty
->driver
->break_ctl(tty
, 0);
3167 mutex_unlock(&tty
->atomic_write_lock
);
3168 if (signal_pending(current
))
3174 * tiocmget - get modem status
3176 * @file: user file pointer
3177 * @p: pointer to result
3179 * Obtain the modem status bits from the tty driver if the feature
3180 * is supported. Return -EINVAL if it is not available.
3182 * Locking: none (up to the driver)
3185 static int tty_tiocmget(struct tty_struct
*tty
, struct file
*file
, int __user
*p
)
3187 int retval
= -EINVAL
;
3189 if (tty
->driver
->tiocmget
) {
3190 retval
= tty
->driver
->tiocmget(tty
, file
);
3193 retval
= put_user(retval
, p
);
3199 * tiocmset - set modem status
3201 * @file: user file pointer
3202 * @cmd: command - clear bits, set bits or set all
3203 * @p: pointer to desired bits
3205 * Set the modem status bits from the tty driver if the feature
3206 * is supported. Return -EINVAL if it is not available.
3208 * Locking: none (up to the driver)
3211 static int tty_tiocmset(struct tty_struct
*tty
, struct file
*file
, unsigned int cmd
,
3214 int retval
= -EINVAL
;
3216 if (tty
->driver
->tiocmset
) {
3217 unsigned int set
, clear
, val
;
3219 retval
= get_user(val
, p
);
3237 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3238 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
3240 retval
= tty
->driver
->tiocmset(tty
, file
, set
, clear
);
3246 * Split this up, as gcc can choke on it otherwise..
3248 int tty_ioctl(struct inode
* inode
, struct file
* file
,
3249 unsigned int cmd
, unsigned long arg
)
3251 struct tty_struct
*tty
, *real_tty
;
3252 void __user
*p
= (void __user
*)arg
;
3254 struct tty_ldisc
*ld
;
3256 tty
= (struct tty_struct
*)file
->private_data
;
3257 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3260 /* CHECKME: is this safe as one end closes ? */
3263 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
3264 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
3265 real_tty
= tty
->link
;
3268 * Break handling by driver
3270 if (!tty
->driver
->break_ctl
) {
3274 if (tty
->driver
->ioctl
)
3275 return tty
->driver
->ioctl(tty
, file
, cmd
, arg
);
3278 /* These two ioctl's always return success; even if */
3279 /* the driver doesn't support them. */
3282 if (!tty
->driver
->ioctl
)
3284 retval
= tty
->driver
->ioctl(tty
, file
, cmd
, arg
);
3285 if (retval
== -ENOIOCTLCMD
)
3292 * Factor out some common prep work
3300 retval
= tty_check_change(tty
);
3303 if (cmd
!= TIOCCBRK
) {
3304 tty_wait_until_sent(tty
, 0);
3305 if (signal_pending(current
))
3313 return tiocsti(tty
, p
);
3315 return tiocgwinsz(tty
, p
);
3317 return tiocswinsz(tty
, real_tty
, p
);
3319 return real_tty
!=tty
? -EINVAL
: tioccons(file
);
3321 return fionbio(file
, p
);
3323 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3326 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
3329 if (current
->signal
->tty
!= tty
)
3334 return tiocsctty(tty
, arg
);
3336 return tiocgpgrp(tty
, real_tty
, p
);
3338 return tiocspgrp(tty
, real_tty
, p
);
3340 return tiocgsid(tty
, real_tty
, p
);
3342 /* FIXME: check this is ok */
3343 return put_user(tty
->ldisc
.num
, (int __user
*)p
);
3345 return tiocsetd(tty
, p
);
3348 return tioclinux(tty
, arg
);
3353 case TIOCSBRK
: /* Turn break on, unconditionally */
3354 tty
->driver
->break_ctl(tty
, -1);
3357 case TIOCCBRK
: /* Turn break off, unconditionally */
3358 tty
->driver
->break_ctl(tty
, 0);
3360 case TCSBRK
: /* SVID version: non-zero arg --> no break */
3361 /* non-zero arg means wait for all output data
3362 * to be sent (performed above) but don't send break.
3363 * This is used by the tcdrain() termios function.
3366 return send_break(tty
, 250);
3368 case TCSBRKP
: /* support for POSIX tcsendbreak() */
3369 return send_break(tty
, arg
? arg
*100 : 250);
3372 return tty_tiocmget(tty
, file
, p
);
3377 return tty_tiocmset(tty
, file
, cmd
, p
);
3382 /* flush tty buffer and allow ldisc to process ioctl */
3383 tty_buffer_flush(tty
);
3388 if (tty
->driver
->ioctl
) {
3389 retval
= (tty
->driver
->ioctl
)(tty
, file
, cmd
, arg
);
3390 if (retval
!= -ENOIOCTLCMD
)
3393 ld
= tty_ldisc_ref_wait(tty
);
3396 retval
= ld
->ioctl(tty
, file
, cmd
, arg
);
3397 if (retval
== -ENOIOCTLCMD
)
3400 tty_ldisc_deref(ld
);
3404 #ifdef CONFIG_COMPAT
3405 static long tty_compat_ioctl(struct file
* file
, unsigned int cmd
,
3408 struct inode
*inode
= file
->f_dentry
->d_inode
;
3409 struct tty_struct
*tty
= file
->private_data
;
3410 struct tty_ldisc
*ld
;
3411 int retval
= -ENOIOCTLCMD
;
3413 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
3416 if (tty
->driver
->compat_ioctl
) {
3417 retval
= (tty
->driver
->compat_ioctl
)(tty
, file
, cmd
, arg
);
3418 if (retval
!= -ENOIOCTLCMD
)
3422 ld
= tty_ldisc_ref_wait(tty
);
3423 if (ld
->compat_ioctl
)
3424 retval
= ld
->compat_ioctl(tty
, file
, cmd
, arg
);
3425 tty_ldisc_deref(ld
);
3432 * This implements the "Secure Attention Key" --- the idea is to
3433 * prevent trojan horses by killing all processes associated with this
3434 * tty when the user hits the "Secure Attention Key". Required for
3435 * super-paranoid applications --- see the Orange Book for more details.
3437 * This code could be nicer; ideally it should send a HUP, wait a few
3438 * seconds, then send a INT, and then a KILL signal. But you then
3439 * have to coordinate with the init process, since all processes associated
3440 * with the current tty must be dead before the new getty is allowed
3443 * Now, if it would be correct ;-/ The current code has a nasty hole -
3444 * it doesn't catch files in flight. We may send the descriptor to ourselves
3445 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
3447 * Nasty bug: do_SAK is being called in interrupt context. This can
3448 * deadlock. We punt it up to process context. AKPM - 16Mar2001
3450 void __do_SAK(struct tty_struct
*tty
)
3455 struct task_struct
*g
, *p
;
3456 struct pid
*session
;
3459 struct fdtable
*fdt
;
3463 session
= tty
->session
;
3465 tty_ldisc_flush(tty
);
3467 if (tty
->driver
->flush_buffer
)
3468 tty
->driver
->flush_buffer(tty
);
3470 read_lock(&tasklist_lock
);
3471 /* Kill the entire session */
3472 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
3473 printk(KERN_NOTICE
"SAK: killed process %d"
3474 " (%s): process_session(p)==tty->session\n",
3476 send_sig(SIGKILL
, p
, 1);
3477 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
3478 /* Now kill any processes that happen to have the
3481 do_each_thread(g
, p
) {
3482 if (p
->signal
->tty
== tty
) {
3483 printk(KERN_NOTICE
"SAK: killed process %d"
3484 " (%s): process_session(p)==tty->session\n",
3486 send_sig(SIGKILL
, p
, 1);
3492 * We don't take a ref to the file, so we must
3493 * hold ->file_lock instead.
3495 spin_lock(&p
->files
->file_lock
);
3496 fdt
= files_fdtable(p
->files
);
3497 for (i
=0; i
< fdt
->max_fds
; i
++) {
3498 filp
= fcheck_files(p
->files
, i
);
3501 if (filp
->f_op
->read
== tty_read
&&
3502 filp
->private_data
== tty
) {
3503 printk(KERN_NOTICE
"SAK: killed process %d"
3504 " (%s): fd#%d opened to the tty\n",
3505 p
->pid
, p
->comm
, i
);
3506 force_sig(SIGKILL
, p
);
3510 spin_unlock(&p
->files
->file_lock
);
3513 } while_each_thread(g
, p
);
3514 read_unlock(&tasklist_lock
);
3518 static void do_SAK_work(struct work_struct
*work
)
3520 struct tty_struct
*tty
=
3521 container_of(work
, struct tty_struct
, SAK_work
);
3526 * The tq handling here is a little racy - tty->SAK_work may already be queued.
3527 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
3528 * the values which we write to it will be identical to the values which it
3529 * already has. --akpm
3531 void do_SAK(struct tty_struct
*tty
)
3535 schedule_work(&tty
->SAK_work
);
3538 EXPORT_SYMBOL(do_SAK
);
3542 * @work: tty structure passed from work queue.
3544 * This routine is called out of the software interrupt to flush data
3545 * from the buffer chain to the line discipline.
3547 * Locking: holds tty->buf.lock to guard buffer list. Drops the lock
3548 * while invoking the line discipline receive_buf method. The
3549 * receive_buf method is single threaded for each tty instance.
3552 static void flush_to_ldisc(struct work_struct
*work
)
3554 struct tty_struct
*tty
=
3555 container_of(work
, struct tty_struct
, buf
.work
.work
);
3556 unsigned long flags
;
3557 struct tty_ldisc
*disc
;
3558 struct tty_buffer
*tbuf
, *head
;
3560 unsigned char *flag_buf
;
3562 disc
= tty_ldisc_ref(tty
);
3563 if (disc
== NULL
) /* !TTY_LDISC */
3566 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3567 head
= tty
->buf
.head
;
3569 tty
->buf
.head
= NULL
;
3571 int count
= head
->commit
- head
->read
;
3573 if (head
->next
== NULL
)
3577 tty_buffer_free(tty
, tbuf
);
3580 if (!tty
->receive_room
) {
3581 schedule_delayed_work(&tty
->buf
.work
, 1);
3584 if (count
> tty
->receive_room
)
3585 count
= tty
->receive_room
;
3586 char_buf
= head
->char_buf_ptr
+ head
->read
;
3587 flag_buf
= head
->flag_buf_ptr
+ head
->read
;
3588 head
->read
+= count
;
3589 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3590 disc
->receive_buf(tty
, char_buf
, flag_buf
, count
);
3591 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3593 tty
->buf
.head
= head
;
3595 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3597 tty_ldisc_deref(disc
);
3601 * tty_flip_buffer_push - terminal
3604 * Queue a push of the terminal flip buffers to the line discipline. This
3605 * function must not be called from IRQ context if tty->low_latency is set.
3607 * In the event of the queue being busy for flipping the work will be
3608 * held off and retried later.
3610 * Locking: tty buffer lock. Driver locks in low latency mode.
3613 void tty_flip_buffer_push(struct tty_struct
*tty
)
3615 unsigned long flags
;
3616 spin_lock_irqsave(&tty
->buf
.lock
, flags
);
3617 if (tty
->buf
.tail
!= NULL
)
3618 tty
->buf
.tail
->commit
= tty
->buf
.tail
->used
;
3619 spin_unlock_irqrestore(&tty
->buf
.lock
, flags
);
3621 if (tty
->low_latency
)
3622 flush_to_ldisc(&tty
->buf
.work
.work
);
3624 schedule_delayed_work(&tty
->buf
.work
, 1);
3627 EXPORT_SYMBOL(tty_flip_buffer_push
);
3631 * initialize_tty_struct
3632 * @tty: tty to initialize
3634 * This subroutine initializes a tty structure that has been newly
3637 * Locking: none - tty in question must not be exposed at this point
3640 static void initialize_tty_struct(struct tty_struct
*tty
)
3642 memset(tty
, 0, sizeof(struct tty_struct
));
3643 tty
->magic
= TTY_MAGIC
;
3644 tty_ldisc_assign(tty
, tty_ldisc_get(N_TTY
));
3645 tty
->session
= NULL
;
3647 tty
->overrun_time
= jiffies
;
3648 tty
->buf
.head
= tty
->buf
.tail
= NULL
;
3649 tty_buffer_init(tty
);
3650 INIT_DELAYED_WORK(&tty
->buf
.work
, flush_to_ldisc
);
3651 init_MUTEX(&tty
->buf
.pty_sem
);
3652 mutex_init(&tty
->termios_mutex
);
3653 init_waitqueue_head(&tty
->write_wait
);
3654 init_waitqueue_head(&tty
->read_wait
);
3655 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
3656 mutex_init(&tty
->atomic_read_lock
);
3657 mutex_init(&tty
->atomic_write_lock
);
3658 spin_lock_init(&tty
->read_lock
);
3659 INIT_LIST_HEAD(&tty
->tty_files
);
3660 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
3664 * The default put_char routine if the driver did not define one.
3667 static void tty_default_put_char(struct tty_struct
*tty
, unsigned char ch
)
3669 tty
->driver
->write(tty
, &ch
, 1);
3672 static struct class *tty_class
;
3675 * tty_register_device - register a tty device
3676 * @driver: the tty driver that describes the tty device
3677 * @index: the index in the tty driver for this tty device
3678 * @device: a struct device that is associated with this tty device.
3679 * This field is optional, if there is no known struct device
3680 * for this tty device it can be set to NULL safely.
3682 * Returns a pointer to the struct device for this tty device
3683 * (or ERR_PTR(-EFOO) on error).
3685 * This call is required to be made to register an individual tty device
3686 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3687 * that bit is not set, this function should not be called by a tty
3693 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3694 struct device
*device
)
3697 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3699 if (index
>= driver
->num
) {
3700 printk(KERN_ERR
"Attempt to register invalid tty line number "
3702 return ERR_PTR(-EINVAL
);
3705 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3706 pty_line_name(driver
, index
, name
);
3708 tty_line_name(driver
, index
, name
);
3710 return device_create(tty_class
, device
, dev
, name
);
3714 * tty_unregister_device - unregister a tty device
3715 * @driver: the tty driver that describes the tty device
3716 * @index: the index in the tty driver for this tty device
3718 * If a tty device is registered with a call to tty_register_device() then
3719 * this function must be called when the tty device is gone.
3724 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3726 device_destroy(tty_class
, MKDEV(driver
->major
, driver
->minor_start
) + index
);
3729 EXPORT_SYMBOL(tty_register_device
);
3730 EXPORT_SYMBOL(tty_unregister_device
);
3732 struct tty_driver
*alloc_tty_driver(int lines
)
3734 struct tty_driver
*driver
;
3736 driver
= kmalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3738 memset(driver
, 0, sizeof(struct tty_driver
));
3739 driver
->magic
= TTY_DRIVER_MAGIC
;
3740 driver
->num
= lines
;
3741 /* later we'll move allocation of tables here */
3746 void put_tty_driver(struct tty_driver
*driver
)
3751 void tty_set_operations(struct tty_driver
*driver
,
3752 const struct tty_operations
*op
)
3754 driver
->open
= op
->open
;
3755 driver
->close
= op
->close
;
3756 driver
->write
= op
->write
;
3757 driver
->put_char
= op
->put_char
;
3758 driver
->flush_chars
= op
->flush_chars
;
3759 driver
->write_room
= op
->write_room
;
3760 driver
->chars_in_buffer
= op
->chars_in_buffer
;
3761 driver
->ioctl
= op
->ioctl
;
3762 driver
->compat_ioctl
= op
->compat_ioctl
;
3763 driver
->set_termios
= op
->set_termios
;
3764 driver
->throttle
= op
->throttle
;
3765 driver
->unthrottle
= op
->unthrottle
;
3766 driver
->stop
= op
->stop
;
3767 driver
->start
= op
->start
;
3768 driver
->hangup
= op
->hangup
;
3769 driver
->break_ctl
= op
->break_ctl
;
3770 driver
->flush_buffer
= op
->flush_buffer
;
3771 driver
->set_ldisc
= op
->set_ldisc
;
3772 driver
->wait_until_sent
= op
->wait_until_sent
;
3773 driver
->send_xchar
= op
->send_xchar
;
3774 driver
->read_proc
= op
->read_proc
;
3775 driver
->write_proc
= op
->write_proc
;
3776 driver
->tiocmget
= op
->tiocmget
;
3777 driver
->tiocmset
= op
->tiocmset
;
3781 EXPORT_SYMBOL(alloc_tty_driver
);
3782 EXPORT_SYMBOL(put_tty_driver
);
3783 EXPORT_SYMBOL(tty_set_operations
);
3786 * Called by a tty driver to register itself.
3788 int tty_register_driver(struct tty_driver
*driver
)
3795 if (driver
->flags
& TTY_DRIVER_INSTALLED
)
3798 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
3799 p
= kzalloc(driver
->num
* 3 * sizeof(void *), GFP_KERNEL
);
3804 if (!driver
->major
) {
3805 error
= alloc_chrdev_region(&dev
, driver
->minor_start
, driver
->num
,
3808 driver
->major
= MAJOR(dev
);
3809 driver
->minor_start
= MINOR(dev
);
3812 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3813 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3821 driver
->ttys
= (struct tty_struct
**)p
;
3822 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
3823 driver
->termios_locked
= (struct ktermios
**)(p
+ driver
->num
* 2);
3825 driver
->ttys
= NULL
;
3826 driver
->termios
= NULL
;
3827 driver
->termios_locked
= NULL
;
3830 cdev_init(&driver
->cdev
, &tty_fops
);
3831 driver
->cdev
.owner
= driver
->owner
;
3832 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
3834 unregister_chrdev_region(dev
, driver
->num
);
3835 driver
->ttys
= NULL
;
3836 driver
->termios
= driver
->termios_locked
= NULL
;
3841 if (!driver
->put_char
)
3842 driver
->put_char
= tty_default_put_char
;
3844 mutex_lock(&tty_mutex
);
3845 list_add(&driver
->tty_drivers
, &tty_drivers
);
3846 mutex_unlock(&tty_mutex
);
3848 if ( !(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
) ) {
3849 for(i
= 0; i
< driver
->num
; i
++)
3850 tty_register_device(driver
, i
, NULL
);
3852 proc_tty_register_driver(driver
);
3856 EXPORT_SYMBOL(tty_register_driver
);
3859 * Called by a tty driver to unregister itself.
3861 int tty_unregister_driver(struct tty_driver
*driver
)
3864 struct ktermios
*tp
;
3867 if (driver
->refcount
)
3870 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3872 mutex_lock(&tty_mutex
);
3873 list_del(&driver
->tty_drivers
);
3874 mutex_unlock(&tty_mutex
);
3877 * Free the termios and termios_locked structures because
3878 * we don't want to get memory leaks when modular tty
3879 * drivers are removed from the kernel.
3881 for (i
= 0; i
< driver
->num
; i
++) {
3882 tp
= driver
->termios
[i
];
3884 driver
->termios
[i
] = NULL
;
3887 tp
= driver
->termios_locked
[i
];
3889 driver
->termios_locked
[i
] = NULL
;
3892 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3893 tty_unregister_device(driver
, i
);
3896 proc_tty_unregister_driver(driver
);
3897 driver
->ttys
= NULL
;
3898 driver
->termios
= driver
->termios_locked
= NULL
;
3900 cdev_del(&driver
->cdev
);
3903 EXPORT_SYMBOL(tty_unregister_driver
);
3905 dev_t
tty_devnum(struct tty_struct
*tty
)
3907 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3909 EXPORT_SYMBOL(tty_devnum
);
3911 void proc_clear_tty(struct task_struct
*p
)
3913 spin_lock_irq(&p
->sighand
->siglock
);
3914 p
->signal
->tty
= NULL
;
3915 spin_unlock_irq(&p
->sighand
->siglock
);
3917 EXPORT_SYMBOL(proc_clear_tty
);
3919 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3922 /* We should not have a session or pgrp to here but.... */
3923 put_pid(tty
->session
);
3925 tty
->session
= get_pid(task_session(tsk
));
3926 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3928 put_pid(tsk
->signal
->tty_old_pgrp
);
3929 tsk
->signal
->tty
= tty
;
3930 tsk
->signal
->tty_old_pgrp
= NULL
;
3933 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3935 spin_lock_irq(&tsk
->sighand
->siglock
);
3936 __proc_set_tty(tsk
, tty
);
3937 spin_unlock_irq(&tsk
->sighand
->siglock
);
3940 struct tty_struct
*get_current_tty(void)
3942 struct tty_struct
*tty
;
3943 WARN_ON_ONCE(!mutex_is_locked(&tty_mutex
));
3944 tty
= current
->signal
->tty
;
3946 * session->tty can be changed/cleared from under us, make sure we
3947 * issue the load. The obtained pointer, when not NULL, is valid as
3948 * long as we hold tty_mutex.
3953 EXPORT_SYMBOL_GPL(get_current_tty
);
3956 * Initialize the console device. This is called *early*, so
3957 * we can't necessarily depend on lots of kernel help here.
3958 * Just do some early initializations, and do the complex setup
3961 void __init
console_init(void)
3965 /* Setup the default TTY line discipline. */
3966 (void) tty_register_ldisc(N_TTY
, &tty_ldisc_N_TTY
);
3969 * set up the console device so that later boot sequences can
3970 * inform about problems etc..
3972 call
= __con_initcall_start
;
3973 while (call
< __con_initcall_end
) {
3980 extern int vty_init(void);
3983 static int __init
tty_class_init(void)
3985 tty_class
= class_create(THIS_MODULE
, "tty");
3986 if (IS_ERR(tty_class
))
3987 return PTR_ERR(tty_class
);
3991 postcore_initcall(tty_class_init
);
3993 /* 3/2004 jmc: why do these devices exist? */
3995 static struct cdev tty_cdev
, console_cdev
;
3996 #ifdef CONFIG_UNIX98_PTYS
3997 static struct cdev ptmx_cdev
;
4000 static struct cdev vc0_cdev
;
4004 * Ok, now we can initialize the rest of the tty devices and can count
4005 * on memory allocations, interrupts etc..
4007 static int __init
tty_init(void)
4009 cdev_init(&tty_cdev
, &tty_fops
);
4010 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
4011 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
4012 panic("Couldn't register /dev/tty driver\n");
4013 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), "tty");
4015 cdev_init(&console_cdev
, &console_fops
);
4016 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
4017 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
4018 panic("Couldn't register /dev/console driver\n");
4019 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), "console");
4021 #ifdef CONFIG_UNIX98_PTYS
4022 cdev_init(&ptmx_cdev
, &ptmx_fops
);
4023 if (cdev_add(&ptmx_cdev
, MKDEV(TTYAUX_MAJOR
, 2), 1) ||
4024 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 2), 1, "/dev/ptmx") < 0)
4025 panic("Couldn't register /dev/ptmx driver\n");
4026 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 2), "ptmx");
4030 cdev_init(&vc0_cdev
, &console_fops
);
4031 if (cdev_add(&vc0_cdev
, MKDEV(TTY_MAJOR
, 0), 1) ||
4032 register_chrdev_region(MKDEV(TTY_MAJOR
, 0), 1, "/dev/vc/0") < 0)
4033 panic("Couldn't register /dev/tty0 driver\n");
4034 device_create(tty_class
, NULL
, MKDEV(TTY_MAJOR
, 0), "tty0");
4040 module_init(tty_init
);