提交 0341a4d0 编写于 作者: K Karl Dahlke 提交者: Linus Torvalds

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: NSamuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 f7440b0e
......@@ -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,
&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
......
......@@ -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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