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