diff options
Diffstat (limited to 'drivers/s390/char/ctrlchar.c')
-rw-r--r-- | drivers/s390/char/ctrlchar.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/drivers/s390/char/ctrlchar.c b/drivers/s390/char/ctrlchar.c new file mode 100644 index 000000000..8de2deb17 --- /dev/null +++ b/drivers/s390/char/ctrlchar.c @@ -0,0 +1,72 @@ +/* + * Unified handling of special chars. + * + * Copyright IBM Corp. 2001 + * 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 void +ctrlchar_handle_sysrq(struct work_struct *work) +{ + handle_sysrq(ctrlchar_sysrq_key); +} + +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]; + 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; +} |