/* * drivers/s390/char/ctrlchar.c * Unified handling of special chars. * * Copyright (C) 2001 IBM Deutschland Entwicklung GmbH, IBM Corporation * 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_SYSRQ static int ctrlchar_sysrq_key; static struct tty_struct *sysrq_tty; static void ctrlchar_handle_sysrq(struct work_struct *work) { handle_sysrq(ctrlchar_sysrq_key, sysrq_tty); } static DECLARE_WORK(ctrlchar_work, ctrlchar_handle_sysrq); #endif /** * Check for special chars at start of input. * * @param buf Console input buffer. * @param len Length of valid data in buffer. * @param 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 int ctrlchar_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]; sysrq_tty = tty; schedule_work(&ctrlchar_work); 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; }