1 // SPDX-License-Identifier: GPL-2.0
3 * Unified handling of special chars.
5 * Copyright IBM Corp. 2001
10 #include <linux/stddef.h>
11 #include <asm/errno.h>
12 #include <linux/sysrq.h>
13 #include <linux/ctype.h>
17 #ifdef CONFIG_MAGIC_SYSRQ
18 static struct sysrq_work ctrlchar_sysrq;
21 ctrlchar_handle_sysrq(struct work_struct *work)
23 struct sysrq_work *sysrq = container_of(work, struct sysrq_work, work);
25 handle_sysrq(sysrq->key);
28 void schedule_sysrq_work(struct sysrq_work *sw)
30 INIT_WORK(&sw->work, ctrlchar_handle_sysrq);
31 schedule_work(&sw->work);
37 * Check for special chars at start of input.
39 * @param buf Console input buffer.
40 * @param len Length of valid data in buffer.
41 * @param tty The tty struct for this console.
42 * @return CTRLCHAR_NONE, if nothing matched,
43 * CTRLCHAR_SYSRQ, if sysrq was encountered
44 * otherwise char to be inserted logically or'ed
48 ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty)
50 if ((len < 2) || (len > 3))
53 /* hat is 0xb1 in codepage 037 (US etc.) and thus */
54 /* converted to 0x5e in ascii ('^') */
55 if ((buf[0] != '^') && (buf[0] != '\252'))
58 #ifdef CONFIG_MAGIC_SYSRQ
60 if (len == 3 && buf[1] == '-') {
61 ctrlchar_sysrq.key = buf[2];
62 schedule_sysrq_work(&ctrlchar_sysrq);
63 return CTRLCHAR_SYSRQ;
70 switch (tolower(buf[1])) {
72 return INTR_CHAR(tty) | CTRLCHAR_CTRL;
74 return EOF_CHAR(tty) | CTRLCHAR_CTRL;
76 return SUSP_CHAR(tty) | CTRLCHAR_CTRL;