linux/drivers/s390/char/ctrlchar.c
Hendrik Brueckner ab7373bf23 s390/ctrlchar: improve handling of magic sysrequests
Extract the sysrq handling from the ctrlchar_handle() into a separate
function that can be directly used by other users.

Introduce a new sysrq_work structure to embed the work_struct and to
specify the magic sysrq function to be invoked.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-08-26 17:20:44 +02:00

79 lines
1.7 KiB
C

/*
* 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 struct sysrq_work ctrlchar_sysrq;
static void
ctrlchar_handle_sysrq(struct work_struct *work)
{
struct sysrq_work *sysrq = container_of(work, struct sysrq_work, work);
handle_sysrq(sysrq->key);
}
void schedule_sysrq_work(struct sysrq_work *sw)
{
INIT_WORK(&sw->work, ctrlchar_handle_sysrq);
schedule_work(&sw->work);
}
#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_sysrq_work(&ctrlchar_sysrq);
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;
}