ctrlchar.c

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/*
 *  Unified handling of special chars.
 *
 *    Copyright IBM Corp. 2001
 *    Author(s): Fritz Elfert <[email protected]> <[email protected]>
 *
 */

#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


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;
}