// SPDX-License-Identifier: GPL-2.0/* *  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_SYSRQstatic struct sysrq_work ctrlchar_sysrq; static voidctrlchar_handle_sysrq(struct work_struct *work){	struct sysrq_work *sysrq = container_of(work, struct sysrq_work, work); 	handle_sysrq(sysrq->key);} void schedule_sysrq_work(struct sysrq_work *sw){	INIT_WORK(&sw->work, ctrlchar_handle_sysrq);	schedule_work(&sw->work);}#endif  /** * ctrlchar_handle - check for special chars at start of input * * @buf: console input buffer * @len: length of valid data in buffer * @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 intctrlchar_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_sysrq_work(&ctrlchar_sysrq);		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;}