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Commit 0341a4d0 authored by Karl Dahlke's avatar Karl Dahlke Committed by Linus Torvalds
Browse files

VT notifier extension for accessibility 



Some accessibility modules need to be able to catch the output on the
console before the VT interpretation, and possibly swallow it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarSamuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f7440b0e

drivers/char/vt.c

+8 −0
Original line number Diff line number Diff line
@@ -2054,6 +2054,7 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co 
	unsigned long draw_from = 0, draw_to = 0;

	struct vc_data *vc;

	unsigned char vc_attr;

	struct vt_notifier_param param;

	uint8_t rescan;

	uint8_t inverse;

	uint8_t width;
@@ -2113,6 +2114,8 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co 
	if (IS_FG(vc))

		hide_cursor(vc);



	param.vc = vc;



	while (!tty->stopped && count) {

		int orig = *buf;

		c = orig;
@@ -2201,6 +2204,11 @@ rescan_last_byte: 
		    tc = vc->vc_translate[vc->vc_toggle_meta ? (c | 0x80) : c];

		}



		param.c = tc;

		if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE,

					&param) == NOTIFY_STOP)

			continue;



                /* If the original code was a control character we

                 * only allow a glyph to be displayed if the code is

                 * not normally used (such as for cursor movement) or

include/linux/notifier.h

+1 −0
Original line number Diff line number Diff line
@@ -247,6 +247,7 @@ extern struct blocking_notifier_head reboot_notifier_list; 
#define VT_DEALLOCATE		0x0002 /* Console will be deallocated */

#define VT_WRITE		0x0003 /* A char got output */

#define VT_UPDATE		0x0004 /* A bigger update occurred */

#define VT_PREWRITE		0x0005 /* A char is about to be written to the console */



#endif /* __KERNEL__ */

#endif /* _LINUX_NOTIFIER_H */