Input: implement SysRq as a separate input handler
Instead of keeping SysRq support inside of legacy keyboard driver split
it out into a separate input handler (filter). This stops most SysRq input
events from leaking into evdev clients (some events, such as first SysRq
scancode - not keycode - event, are still leaked into both legacy keyboard
and evdev).
[martinez.javier@gmail.com: fix compile error when CONFIG_MAGIC_SYSRQ is
not defined]
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 59de252..193f9c2 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -1,7 +1,4 @@
-/* -*- linux-c -*-
- *
- * $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
- *
+/*
* Linux Magic System Request Key Hacks
*
* (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
@@ -10,8 +7,13 @@
* (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
* overhauled to use key registration
* based upon discusions in irc://irc.openprojects.net/#kernelnewbies
+ *
+ * Copyright (c) 2010 Dmitry Torokhov
+ * Input handler conversion
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
@@ -39,33 +41,34 @@
#include <linux/hrtimer.h>
#include <linux/oom.h>
#include <linux/slab.h>
+#include <linux/input.h>
#include <asm/ptrace.h>
#include <asm/irq_regs.h>
/* Whether we react on sysrq keys or just ignore them */
-int __read_mostly __sysrq_enabled = 1;
+static int __read_mostly sysrq_enabled = 1;
+static bool __read_mostly sysrq_always_enabled;
-static int __read_mostly sysrq_always_enabled;
-
-int sysrq_on(void)
+static bool sysrq_on(void)
{
- return __sysrq_enabled || sysrq_always_enabled;
+ return sysrq_enabled || sysrq_always_enabled;
}
/*
* A value of 1 means 'all', other nonzero values are an op mask:
*/
-static inline int sysrq_on_mask(int mask)
+static bool sysrq_on_mask(int mask)
{
- return sysrq_always_enabled || __sysrq_enabled == 1 ||
- (__sysrq_enabled & mask);
+ return sysrq_always_enabled ||
+ sysrq_enabled == 1 ||
+ (sysrq_enabled & mask);
}
static int __init sysrq_always_enabled_setup(char *str)
{
- sysrq_always_enabled = 1;
- printk(KERN_INFO "debug: sysrq always enabled.\n");
+ sysrq_always_enabled = true;
+ pr_info("sysrq always enabled.\n");
return 1;
}
@@ -76,6 +79,7 @@
static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
{
int i;
+
i = key - '0';
console_loglevel = 7;
printk("Loglevel set to %d\n", i);
@@ -101,7 +105,7 @@
.enable_mask = SYSRQ_ENABLE_KEYBOARD,
};
#else
-#define sysrq_SAK_op (*(struct sysrq_key_op *)0)
+#define sysrq_SAK_op (*(struct sysrq_key_op *)NULL)
#endif
#ifdef CONFIG_VT
@@ -119,7 +123,7 @@
.enable_mask = SYSRQ_ENABLE_KEYBOARD,
};
#else
-#define sysrq_unraw_op (*(struct sysrq_key_op *)0)
+#define sysrq_unraw_op (*(struct sysrq_key_op *)NULL)
#endif /* CONFIG_VT */
static void sysrq_handle_crash(int key, struct tty_struct *tty)
@@ -195,7 +199,7 @@
.action_msg = "Show Locks Held",
};
#else
-#define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
+#define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL)
#endif
#ifdef CONFIG_SMP
@@ -298,7 +302,7 @@
.enable_mask = SYSRQ_ENABLE_DUMP,
};
#else
-#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)0)
+#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL)
#endif
static void sysrq_handle_showmem(int key, struct tty_struct *tty)
@@ -477,6 +481,7 @@
i = sysrq_key_table_key2index(key);
if (i != -1)
op_p = sysrq_key_table[i];
+
return op_p;
}
@@ -488,11 +493,7 @@
sysrq_key_table[i] = op_p;
}
-/*
- * This is the non-locking version of handle_sysrq. It must/can only be called
- * by sysrq key handlers, as they are inside of the lock
- */
-void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
+static void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
{
struct sysrq_key_op *op_p;
int orig_log_level;
@@ -544,10 +545,6 @@
spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
}
-/*
- * This function is called by the keyboard handler when SysRq is pressed
- * and any other keycode arrives.
- */
void handle_sysrq(int key, struct tty_struct *tty)
{
if (sysrq_on())
@@ -555,10 +552,177 @@
}
EXPORT_SYMBOL(handle_sysrq);
+#ifdef CONFIG_INPUT
+
+/* Simple translation table for the SysRq keys */
+static const unsigned char sysrq_xlate[KEY_MAX + 1] =
+ "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */
+ "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */
+ "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */
+ "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */
+ "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */
+ "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */
+ "\r\000/"; /* 0x60 - 0x6f */
+
+static bool sysrq_down;
+static int sysrq_alt_use;
+static int sysrq_alt;
+
+static bool sysrq_filter(struct input_handle *handle, unsigned int type,
+ unsigned int code, int value)
+{
+ if (type != EV_KEY)
+ goto out;
+
+ switch (code) {
+
+ case KEY_LEFTALT:
+ case KEY_RIGHTALT:
+ if (value)
+ sysrq_alt = code;
+ else if (sysrq_down && code == sysrq_alt_use)
+ sysrq_down = false;
+ break;
+
+ case KEY_SYSRQ:
+ if (value == 1 && sysrq_alt) {
+ sysrq_down = true;
+ sysrq_alt_use = sysrq_alt;
+ }
+ break;
+
+ default:
+ if (sysrq_down && value && value != 2)
+ __handle_sysrq(sysrq_xlate[code], NULL, 1);
+ break;
+ }
+
+out:
+ return sysrq_down;
+}
+
+static int sysrq_connect(struct input_handler *handler,
+ struct input_dev *dev,
+ const struct input_device_id *id)
+{
+ struct input_handle *handle;
+ int error;
+
+ sysrq_down = false;
+ sysrq_alt = 0;
+
+ handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
+ if (!handle)
+ return -ENOMEM;
+
+ handle->dev = dev;
+ handle->handler = handler;
+ handle->name = "sysrq";
+
+ error = input_register_handle(handle);
+ if (error) {
+ pr_err("Failed to register input sysrq handler, error %d\n",
+ error);
+ goto err_free;
+ }
+
+ error = input_open_device(handle);
+ if (error) {
+ pr_err("Failed to open input device, error %d\n", error);
+ goto err_unregister;
+ }
+
+ return 0;
+
+ err_unregister:
+ input_unregister_handle(handle);
+ err_free:
+ kfree(handle);
+ return error;
+}
+
+static void sysrq_disconnect(struct input_handle *handle)
+{
+ input_close_device(handle);
+ input_unregister_handle(handle);
+ kfree(handle);
+}
+
+/*
+ * We are matching on KEY_LEFTALT insteard of KEY_SYSRQ because not all
+ * keyboards have SysRq ikey predefined and so user may add it to keymap
+ * later, but we expect all such keyboards to have left alt.
+ */
+static const struct input_device_id sysrq_ids[] = {
+ {
+ .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+ INPUT_DEVICE_ID_MATCH_KEYBIT,
+ .evbit = { BIT_MASK(EV_KEY) },
+ .keybit = { BIT_MASK(KEY_LEFTALT) },
+ },
+ { },
+};
+
+static struct input_handler sysrq_handler = {
+ .filter = sysrq_filter,
+ .connect = sysrq_connect,
+ .disconnect = sysrq_disconnect,
+ .name = "sysrq",
+ .id_table = sysrq_ids,
+};
+
+static bool sysrq_handler_registered;
+
+static inline void sysrq_register_handler(void)
+{
+ int error;
+
+ error = input_register_handler(&sysrq_handler);
+ if (error)
+ pr_err("Failed to register input handler, error %d", error);
+ else
+ sysrq_handler_registered = true;
+}
+
+static inline void sysrq_unregister_handler(void)
+{
+ if (sysrq_handler_registered) {
+ input_unregister_handler(&sysrq_handler);
+ sysrq_handler_registered = false;
+ }
+}
+
+#else
+
+static inline void sysrq_register_handler(void)
+{
+}
+
+static inline void sysrq_unregister_handler(void)
+{
+}
+
+#endif /* CONFIG_INPUT */
+
+int sysrq_toggle_support(int enable_mask)
+{
+ bool was_enabled = sysrq_on();
+
+ sysrq_enabled = enable_mask;
+
+ if (was_enabled != sysrq_on()) {
+ if (sysrq_on())
+ sysrq_register_handler();
+ else
+ sysrq_unregister_handler();
+ }
+
+ return 0;
+}
+
static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
struct sysrq_key_op *remove_op_p)
{
-
int retval;
unsigned long flags;
@@ -599,6 +763,7 @@
return -EFAULT;
__handle_sysrq(c, NULL, 0);
}
+
return count;
}
@@ -606,10 +771,28 @@
.write = write_sysrq_trigger,
};
+static void sysrq_init_procfs(void)
+{
+ if (!proc_create("sysrq-trigger", S_IWUSR, NULL,
+ &proc_sysrq_trigger_operations))
+ pr_err("Failed to register proc interface\n");
+}
+
+#else
+
+static inline void sysrq_init_procfs(void)
+{
+}
+
+#endif /* CONFIG_PROC_FS */
+
static int __init sysrq_init(void)
{
- proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations);
+ sysrq_init_procfs();
+
+ if (sysrq_on())
+ sysrq_register_handler();
+
return 0;
}
module_init(sysrq_init);
-#endif