From 0341a4d0fdd2a0a3d9e2bb3a9afef9f8292c8502 Mon Sep 17 00:00:00 2001
From: Karl Dahlke <eklhad@comcast.net>
Date: Mon, 28 Apr 2008 02:14:25 -0700
Subject: [PATCH] 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: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/char/vt.c | 8 ++++++++
include/linux/notifier.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 9b58b894f8237..df4c3ead9e2b7 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -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 @@ static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int co
tc = vc->vc_translate[vc->vc_toggle_meta ? (c | 0x80) : c];
}
+ param.c = tc;
+ if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE,
+ ¶m) == 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
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index f4df40038f0c4..20dfed590183c 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -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 */
--
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