1 files changed, 75 insertions, 0 deletions

diff --git a/drivers/s390/char/ctrlchar.c b/drivers/s390/char/ctrlchar.c
new file mode 100644
index 000000000000..be463242cf0f
--- /dev/null
+++ b/drivers/s390/char/ctrlchar.c
@@ -0,0 +1,75 @@
+/*
+ *  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/config.h>
+#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(void *tty)
+{
+        handle_sysrq(ctrlchar_sysrq_key, NULL, (struct tty_struct *) tty);
+}
+
+static DECLARE_WORK(ctrlchar_work, ctrlchar_handle_sysrq, 0);
+#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];
+                ctrlchar_work.data = 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;
+}