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sys/kern/subr_kdb.c:

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Modify the "alternate break sequence" detecting state
	machine so that only a contiguous invocation of the
	break sequence is accepted.  The old implementation
	did not reset the state machine when detecting an
	unexpected character.

	While here, use an enum for the states of the machine
	instead of magic numbers.bmitted by:

Sponsored by:	Spectra Logic Corporation
This commit is contained in:
Justin T. Gibbs 2011-06-14 21:37:25 +00:00
parent 144b716627
commit 583bef3863
1 changed files with 23 additions and 8 deletions
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31
sys/kern/subr_kdb.c
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@ -244,29 +244,44 @@ kdb_reboot(void)
#define KEY_CRTLP 16 /* ^P */
#define KEY_CRTLR 18 /* ^R */
/* States of th KDB "alternate break sequence" detecting state machine. */
enum {
KDB_ALT_BREAK_SEEN_NONE,
KDB_ALT_BREAK_SEEN_CR,
KDB_ALT_BREAK_SEEN_CR_TILDE,
};
int
kdb_alt_break(int key, int *state)
{
int brk;
/* All states transition to KDB_ALT_BREAK_SEEN_CR on a CR. */
if (key == KEY_CR) {
*state = KDB_ALT_BREAK_SEEN_CR;
return (0);
}
brk = 0;
switch (*state) {
case 0:
if (key == KEY_CR)
*state = 1;
break;
case 1:
case KDB_ALT_BREAK_SEEN_CR:
*state = KDB_ALT_BREAK_SEEN_NONE;
if (key == KEY_TILDE)
*state = 2;
*state = KDB_ALT_BREAK_SEEN_CR_TILDE;
break;
case 2:
case KDB_ALT_BREAK_SEEN_CR_TILDE:
*state = KDB_ALT_BREAK_SEEN_NONE;
if (key == KEY_CRTLB)
brk = KDB_REQ_DEBUGGER;
else if (key == KEY_CRTLP)
brk = KDB_REQ_PANIC;
else if (key == KEY_CRTLR)
brk = KDB_REQ_REBOOT;
*state = 0;
break;
case KDB_ALT_BREAK_SEEN_NONE:
default:
*state = KDB_ALT_BREAK_SEEN_NONE;
break;
}
return (brk);
}