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/*

 *  drivers/s390/char/ctrlchar.c

 *  Unified handling of special chars.

 *

 *    Copyright (C) 2001 IBM Deutschland Entwicklung GmbH, IBM Corporation

 *    Author(s): Fritz Elfert <felfert@millenux.com> <elfert@de.ibm.com>

 *

 */

#include <linux/config.h>

#include <linux/stddef.h>

#include <linux/sysrq.h>

#include <linux/ctype.h>

#include <linux/interrupt.h>

#include "ctrlchar.h"

#ifdef CONFIG_MAGIC_SYSRQ

static int ctrlchar_sysrq_key;

static struct tq_struct ctrlchar_tq;

static void

ctrlchar_handle_sysrq(void *tty)

{

        handle_sysrq(ctrlchar_sysrq_key, NULL, NULL, (struct tty_struct*) tty);

}

#endif

void

ctrlchar_init(void)

{

#ifdef CONFIG_MAGIC_SYSRQ

        static int init_done = 0;

        if (init_done++)

                return;

        INIT_LIST_HEAD(&ctrlchar_tq.list);

        ctrlchar_tq.sync = 0;

        ctrlchar_tq.routine = (void (*)(void *)) 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];

                ctrlchar_tq.data = tty;

                queue_task(&ctrlchar_tq, &tq_immediate);

                mark_bh(IMMEDIATE_BH);

                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;

}