Messages in this thread Patch in this message | | | Date | Fri, 15 Feb 2008 18:25:16 +0100 | From | Samuel Thibault <> | Subject | [PATCH] VT notifier extension for accessibility |
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Some accessibility modules need to be able to catch the output on the console before the VT interpretation, and possibly swallow it.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> From: Karl Dahlke <eklhad@comcast.net>
--- include/linux/notifier.h 2008-02-15 08:44:10.000000000 -0500 +++ include/linux/notifier.h.new 2008-02-15 09:58:00.000000000 -0500 @@ -247,6 +247,7 @@ extern struct blocking_notifier_head reb #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 */ --- drivers/char/vt.c 2008-02-15 08:43:35.000000000 -0500 +++ drivers/char/vt.c.new 2008-02-15 10:11:14.000000000 -0500 @@ -2053,6 +2053,7 @@ static int do_con_write(struct tty_struc 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; @@ -2112,6 +2113,8 @@ static int do_con_write(struct tty_struc if (IS_FG(vc)) hide_cursor(vc); + param.vc = vc; + while (!tty->stopped && count) { int orig = *buf; c = orig; @@ -2200,6 +2203,10 @@ 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, ¶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
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