1/*
 2 *  drivers/s390/char/ctrlchar.c
 3 *  Unified handling of special chars.
 4 *
 5 *    Copyright (C) 2001 IBM Deutschland Entwicklung GmbH, IBM Corporation
 6 *    Author(s): Fritz Elfert <felfert@millenux.com> <elfert@de.ibm.com>
 7 *
 8 */
 9
10#include <linux/stddef.h>
11#include <asm/errno.h>
12#include <linux/sysrq.h>
13#include <linux/ctype.h>
14
15#include "ctrlchar.h"
16
17#ifdef CONFIG_MAGIC_SYSRQ
18static int ctrlchar_sysrq_key;
19
20static void
21ctrlchar_handle_sysrq(struct work_struct *work)
22{
23	handle_sysrq(ctrlchar_sysrq_key);
 
 
24}
25
26static DECLARE_WORK(ctrlchar_work, ctrlchar_handle_sysrq);
 
 
 
 
27#endif
28
29
30/**
31 * Check for special chars at start of input.
 
 
 
 
32 *
33 * @param buf Console input buffer.
34 * @param len Length of valid data in buffer.
35 * @param tty The tty struct for this console.
36 * @return CTRLCHAR_NONE, if nothing matched,
37 *         CTRLCHAR_SYSRQ, if sysrq was encountered
38 *         otherwise char to be inserted logically or'ed
39 *         with CTRLCHAR_CTRL
40 */
41unsigned int
42ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty)
43{
44	if ((len < 2) || (len > 3))
45		return CTRLCHAR_NONE;
46
47	/* hat is 0xb1 in codepage 037 (US etc.) and thus */
48	/* converted to 0x5e in ascii ('^') */
49	if ((buf[0] != '^') && (buf[0] != '\252'))
50		return CTRLCHAR_NONE;
51
52#ifdef CONFIG_MAGIC_SYSRQ
53	/* racy */
54	if (len == 3 && buf[1] == '-') {
55		ctrlchar_sysrq_key = buf[2];
56		schedule_work(&ctrlchar_work);
57		return CTRLCHAR_SYSRQ;
58	}
59#endif
60
61	if (len != 2)
62		return CTRLCHAR_NONE;
63
64	switch (tolower(buf[1])) {
65	case 'c':
66		return INTR_CHAR(tty) | CTRLCHAR_CTRL;
67	case 'd':
68		return EOF_CHAR(tty)  | CTRLCHAR_CTRL;
69	case 'z':
70		return SUSP_CHAR(tty) | CTRLCHAR_CTRL;
71	}
72	return CTRLCHAR_NONE;
73}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 
 3 *  Unified handling of special chars.
 4 *
 5 *    Copyright IBM Corp. 2001
 6 *    Author(s): Fritz Elfert <felfert@millenux.com> <elfert@de.ibm.com>
 7 *
 8 */
 9
10#include <linux/stddef.h>
11#include <asm/errno.h>
12#include <linux/sysrq.h>
13#include <linux/ctype.h>
14
15#include "ctrlchar.h"
16
17#ifdef CONFIG_MAGIC_SYSRQ
18static struct sysrq_work ctrlchar_sysrq;
19
20static void
21ctrlchar_handle_sysrq(struct work_struct *work)
22{
23	struct sysrq_work *sysrq = container_of(work, struct sysrq_work, work);
24
25	handle_sysrq(sysrq->key);
26}
27
28void schedule_sysrq_work(struct sysrq_work *sw)
29{
30	INIT_WORK(&sw->work, ctrlchar_handle_sysrq);
31	schedule_work(&sw->work);
32}
33#endif
34
35
36/**
37 * ctrlchar_handle - check for special chars at start of input
38 *
39 * @buf: console input buffer
40 * @len: length of valid data in buffer
41 * @tty: the tty struct for this console
42 *
43 * Return: CTRLCHAR_NONE, if nothing matched,
 
 
 
44 *         CTRLCHAR_SYSRQ, if sysrq was encountered
45 *         otherwise char to be inserted logically or'ed
46 *         with CTRLCHAR_CTRL
47 */
48unsigned int
49ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty)
50{
51	if ((len < 2) || (len > 3))
52		return CTRLCHAR_NONE;
53
54	/* hat is 0xb1 in codepage 037 (US etc.) and thus */
55	/* converted to 0x5e in ascii ('^') */
56	if ((buf[0] != '^') && (buf[0] != '\252'))
57		return CTRLCHAR_NONE;
58
59#ifdef CONFIG_MAGIC_SYSRQ
60	/* racy */
61	if (len == 3 && buf[1] == '-') {
62		ctrlchar_sysrq.key = buf[2];
63		schedule_sysrq_work(&ctrlchar_sysrq);
64		return CTRLCHAR_SYSRQ;
65	}
66#endif
67
68	if (len != 2)
69		return CTRLCHAR_NONE;
70
71	switch (tolower(buf[1])) {
72	case 'c':
73		return INTR_CHAR(tty) | CTRLCHAR_CTRL;
74	case 'd':
75		return EOF_CHAR(tty)  | CTRLCHAR_CTRL;
76	case 'z':
77		return SUSP_CHAR(tty) | CTRLCHAR_CTRL;
78	}
79	return CTRLCHAR_NONE;
80}