ctrlchar.c
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/*
* Unified handling of special chars.
*
* Copyright IBM Corp. 2001
* Author(s): Fritz Elfert <felfert@millenux.com> <elfert@de.ibm.com>
*
*/
#include <linux/stddef.h>
#include <asm/errno.h>
#include <linux/sysrq.h>
#include <linux/ctype.h>
#include "ctrlchar.h"
#ifdef CONFIG_MAGIC_SYSRQ
static int ctrlchar_sysrq_key;
static void
ctrlchar_handle_sysrq(struct work_struct *work)
{
handle_sysrq(ctrlchar_sysrq_key);
}
static DECLARE_WORK(ctrlchar_work, ctrlchar_handle_sysrq);
#endif
/**
* Check for special chars at start of input.
*
* @param buf Console input buffer.
* @param len Length of valid data in buffer.
* @param tty The tty struct for this console.
* @return CTRLCHAR_NONE, if nothing matched,
* CTRLCHAR_SYSRQ, if sysrq was encountered
* otherwise char to be inserted logically or'ed
* with CTRLCHAR_CTRL
*/
unsigned int
ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty)
{
if ((len < 2) || (len > 3))
return CTRLCHAR_NONE;
/* hat is 0xb1 in codepage 037 (US etc.) and thus */
/* converted to 0x5e in ascii ('^') */
if ((buf[0] != '^') && (buf[0] != '\252'))
return CTRLCHAR_NONE;
#ifdef CONFIG_MAGIC_SYSRQ
/* racy */
if (len == 3 && buf[1] == '-') {
ctrlchar_sysrq_key = buf[2];
schedule_work(&ctrlchar_work);
return CTRLCHAR_SYSRQ;
}
#endif
if (len != 2)
return CTRLCHAR_NONE;
switch (tolower(buf[1])) {
case 'c':
return INTR_CHAR(tty) | CTRLCHAR_CTRL;
case 'd':
return EOF_CHAR(tty) | CTRLCHAR_CTRL;
case 'z':
return SUSP_CHAR(tty) | CTRLCHAR_CTRL;
}
return CTRLCHAR_NONE;
}