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path: root/drivers/s390/char/ctrlchar.c
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Diffstat (limited to 'drivers/s390/char/ctrlchar.c')
-rw-r--r--drivers/s390/char/ctrlchar.c72
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;
+}