// SPDX-License-Identifier: GPL-2.0
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/*
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* Unified handling of special chars.
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*
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* Copyright IBM Corp. 2001
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* Author(s): Fritz Elfert <felfert@millenux.com> <elfert@de.ibm.com>
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*
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*/
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#include <linux/stddef.h>
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#include <asm/errno.h>
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#include <linux/sysrq.h>
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#include <linux/ctype.h>
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#include "ctrlchar.h"
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#ifdef CONFIG_MAGIC_SYSRQ
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static struct sysrq_work ctrlchar_sysrq;
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static void
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ctrlchar_handle_sysrq(struct work_struct *work)
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{
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struct sysrq_work *sysrq = container_of(work, struct sysrq_work, work);
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handle_sysrq(sysrq->key);
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}
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void schedule_sysrq_work(struct sysrq_work *sw)
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{
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INIT_WORK(&sw->work, ctrlchar_handle_sysrq);
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schedule_work(&sw->work);
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}
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#endif
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/**
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* Check for special chars at start of input.
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*
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* @param buf Console input buffer.
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* @param len Length of valid data in buffer.
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* @param tty The tty struct for this console.
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* @return CTRLCHAR_NONE, if nothing matched,
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* CTRLCHAR_SYSRQ, if sysrq was encountered
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* otherwise char to be inserted logically or'ed
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* with CTRLCHAR_CTRL
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*/
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unsigned int
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ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty)
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{
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if ((len < 2) || (len > 3))
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return CTRLCHAR_NONE;
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/* hat is 0xb1 in codepage 037 (US etc.) and thus */
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/* converted to 0x5e in ascii ('^') */
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if ((buf[0] != '^') && (buf[0] != '\252'))
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return CTRLCHAR_NONE;
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#ifdef CONFIG_MAGIC_SYSRQ
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/* racy */
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if (len == 3 && buf[1] == '-') {
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ctrlchar_sysrq.key = buf[2];
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schedule_sysrq_work(&ctrlchar_sysrq);
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return CTRLCHAR_SYSRQ;
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}
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#endif
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if (len != 2)
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return CTRLCHAR_NONE;
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switch (tolower(buf[1])) {
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case 'c':
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return INTR_CHAR(tty) | CTRLCHAR_CTRL;
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case 'd':
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return EOF_CHAR(tty) | CTRLCHAR_CTRL;
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case 'z':
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return SUSP_CHAR(tty) | CTRLCHAR_CTRL;
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}
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return CTRLCHAR_NONE;
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}
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