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 18 static int ctrlchar_sysrq_key; 19 20 static void 21 ctrlchar_handle_sysrq(struct work_struct *work) 22 { 23 handle_sysrq(ctrlchar_sysrq_key); 24 } 25 26 static 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 */ 41 unsigned int 42 ctrlchar_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 } 74