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Commit 6db4063c authored by Antonino A. Daplas's avatar Antonino A. Daplas Committed by Linus Torvalds
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[PATCH] VT binding: Add sysfs control to the VT layer 



Add sysfs control to the VT layer.  A new sysfs class, 'vtconsole', and class
devices 'vtcon[n]' are added.  Each class device file has the following
attributes:

/sys/class/vtconsole/vtcon[n]/name - read-only attribute showing the
                                     name of the current backend

/sys/class/vtconsole/vtcon[n]/bind - read/write attribute
             where: 0 - backend is unbound/unbind backend from the VT layer
                    1 - backend is bound/bind backend to the VT layer

In addition, if any of the consoles are in KD_GRAPHICS mode, binding and
unbinding will not succeed.  KD_GRAPHICS mode usually indicates that the
underlying console hardware is used for other purposes other than displaying
text (ie X).  This feature should prevent binding/unbinding from interfering
with a graphics application using the VT.

[akpm@osdl.org: warning fixes]
Signed-off-by: default avatarAntonino Daplas <adaplas@pol.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 79062a0d

drivers/char/vt.c

+232 −147
Original line number Diff line number Diff line
@@ -100,12 +100,14 @@ 


#define MAX_NR_CON_DRIVER 16



#define CON_DRIVER_FLAG_BIND 1

#define CON_DRIVER_FLAG_MODULE 1

#define CON_DRIVER_FLAG_INIT 2



struct con_driver {

	const struct consw *con;

	const char *desc;

	struct class_device *class_dev;

	int node;

	int first;

	int last;

	int flag;
@@ -2685,6 +2687,25 @@ int __init vty_init(void) 
}



#ifndef VT_SINGLE_DRIVER

#include <linux/device.h>



static struct class *vtconsole_class;



static int con_is_graphics(const struct consw *csw, int first, int last)

{

	int i, retval = 0;



	for (i = first; i <= last; i++) {

		struct vc_data *vc = vc_cons[i].d;



		if (vc && vc->vc_mode == KD_GRAPHICS) {

			retval = 1;

			break;

		}

	}



	return retval;

}



static int bind_con_driver(const struct consw *csw, int first, int last,

			   int deflt)
@@ -2805,7 +2826,7 @@ static int unbind_con_driver(const struct consw *csw, int first, int last, 
		con_driver = &registered_con_driver[i];



		if (con_driver->con == csw &&

		    con_driver->flag & CON_DRIVER_FLAG_BIND) {

		    con_driver->flag & CON_DRIVER_FLAG_MODULE) {

			retval = 0;

			break;

		}
@@ -2816,12 +2837,14 @@ static int unbind_con_driver(const struct consw *csw, int first, int last, 
		goto err;

	}



	retval = -ENODEV;



	/* check if backup driver exists */

	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {

		con_back = &registered_con_driver[i];



		if (con_back->con &&

		    !(con_back->flag & CON_DRIVER_FLAG_BIND)) {

		    !(con_back->flag & CON_DRIVER_FLAG_MODULE)) {

			defcsw = con_back->con;

			retval = 0;

			break;
@@ -2849,21 +2872,177 @@ static int unbind_con_driver(const struct consw *csw, int first, int last, 
	}



	if (!con_is_bound(defcsw)) {

		const struct consw *defconsw = conswitchp;



		defcsw->con_startup();

		con_back->flag |= CON_DRIVER_FLAG_INIT;

		/*

		 * vgacon may change the default driver to point

		 * to dummycon, we restore it here...

		 */

		conswitchp = defconsw;

	}



	if (!con_is_bound(csw))

		con_driver->flag &= ~CON_DRIVER_FLAG_INIT;



	release_console_sem();

	retval = bind_con_driver(defcsw, first, last, deflt);

	/* ignore return value, binding should not fail */

	bind_con_driver(defcsw, first, last, deflt);

err:

	module_put(owner);

	return retval;



}



static int vt_bind(struct con_driver *con)

{

	const struct consw *defcsw = NULL, *csw = NULL;

	int i, more = 1, first = -1, last = -1, deflt = 0;



 	if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE) ||

	    con_is_graphics(con->con, con->first, con->last))

		goto err;



	csw = con->con;



	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {

		struct con_driver *con = &registered_con_driver[i];



		if (con->con && !(con->flag & CON_DRIVER_FLAG_MODULE)) {

			defcsw = con->con;

			break;

		}

	}



	if (!defcsw)

		goto err;



	while (more) {

		more = 0;



		for (i = con->first; i <= con->last; i++) {

			if (con_driver_map[i] == defcsw) {

				if (first == -1)

					first = i;

				last = i;

				more = 1;

			} else if (first != -1)

				break;

		}



		if (first == 0 && last == MAX_NR_CONSOLES -1)

			deflt = 1;



		if (first != -1)

			bind_con_driver(csw, first, last, deflt);



		first = -1;

		last = -1;

		deflt = 0;

	}



err:

	return 0;

}



static int vt_unbind(struct con_driver *con)

{

	const struct consw *csw = NULL;

	int i, more = 1, first = -1, last = -1, deflt = 0;



 	if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE) ||

	    con_is_graphics(con->con, con->first, con->last))

		goto err;



	csw = con->con;



	while (more) {

		more = 0;



		for (i = con->first; i <= con->last; i++) {

			if (con_driver_map[i] == csw) {

				if (first == -1)

					first = i;

				last = i;

				more = 1;

			} else if (first != -1)

				break;

		}



		if (first == 0 && last == MAX_NR_CONSOLES -1)

			deflt = 1;



		if (first != -1)

			unbind_con_driver(csw, first, last, deflt);



		first = -1;

		last = -1;

		deflt = 0;

	}



err:

	return 0;

}



static ssize_t store_bind(struct class_device *class_device,

			  const char *buf, size_t count)

{

	struct con_driver *con = class_get_devdata(class_device);

	int bind = simple_strtoul(buf, NULL, 0);



	if (bind)

		vt_bind(con);

	else

		vt_unbind(con);



	return count;

}



static ssize_t show_bind(struct class_device *class_device, char *buf)

{

	struct con_driver *con = class_get_devdata(class_device);

	int bind = con_is_bound(con->con);



	return snprintf(buf, PAGE_SIZE, "%i\n", bind);

}



static ssize_t show_name(struct class_device *class_device, char *buf)

{

	struct con_driver *con = class_get_devdata(class_device);



	return snprintf(buf, PAGE_SIZE, "%s %s\n",

			(con->flag & CON_DRIVER_FLAG_MODULE) ? "(M)" : "(S)",

			 con->desc);



}



static struct class_device_attribute class_device_attrs[] = {

	__ATTR(bind, S_IRUGO|S_IWUSR, show_bind, store_bind),

	__ATTR(name, S_IRUGO, show_name, NULL),

};



static int vtconsole_init_class_device(struct con_driver *con)

{

	int i;



	class_set_devdata(con->class_dev, con);

	for (i = 0; i < ARRAY_SIZE(class_device_attrs); i++)

		class_device_create_file(con->class_dev,

					 &class_device_attrs[i]);



	return 0;

}



static void vtconsole_deinit_class_device(struct con_driver *con)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(class_device_attrs); i++)

		class_device_remove_file(con->class_dev,

					 &class_device_attrs[i]);

}



/**

 * con_is_bound - checks if driver is bound to the console

 * @csw: console driver
@@ -2934,7 +3113,8 @@ int register_con_driver(const struct consw *csw, int first, int last) 
		if (con_driver->con == NULL) {

			con_driver->con = csw;

			con_driver->desc = desc;

			con_driver->flag = CON_DRIVER_FLAG_BIND |

			con_driver->node = i;

			con_driver->flag = CON_DRIVER_FLAG_MODULE |

			                   CON_DRIVER_FLAG_INIT;

			con_driver->first = first;

			con_driver->last = last;
@@ -2943,6 +3123,22 @@ int register_con_driver(const struct consw *csw, int first, int last) 
		}

	}



	if (retval)

		goto err;



	con_driver->class_dev = class_device_create(vtconsole_class, NULL,

						    MKDEV(0, con_driver->node),

						    NULL, "vtcon%i",

						    con_driver->node);



	if (IS_ERR(con_driver->class_dev)) {

		printk(KERN_WARNING "Unable to create class_device for %s; "

		       "errno = %ld\n", con_driver->desc,

		       PTR_ERR(con_driver->class_dev));

		con_driver->class_dev = NULL;

	} else {

		vtconsole_init_class_device(con_driver);

	}

err:

	release_console_sem();

	module_put(owner);
@@ -2975,9 +3171,14 @@ int unregister_con_driver(const struct consw *csw) 
		struct con_driver *con_driver = &registered_con_driver[i];



		if (con_driver->con == csw &&

		    con_driver->flag & CON_DRIVER_FLAG_BIND) {

		    con_driver->flag & CON_DRIVER_FLAG_MODULE) {

			vtconsole_deinit_class_device(con_driver);

			class_device_destroy(vtconsole_class,

					     MKDEV(0, con_driver->node));

			con_driver->con = NULL;

			con_driver->desc = NULL;

			con_driver->class_dev = NULL;

			con_driver->node = 0;

			con_driver->flag = 0;

			con_driver->first = 0;

			con_driver->last = 0;
@@ -2985,7 +3186,6 @@ int unregister_con_driver(const struct consw *csw) 
			break;

		}

	}



err:

	release_console_sem();

	return retval;
@@ -3006,7 +3206,7 @@ int take_over_console(const struct consw *csw, int first, int last, int deflt) 
	err = register_con_driver(csw, first, last);



	if (!err)

		err = bind_con_driver(csw, first, last, deflt);

		bind_con_driver(csw, first, last, deflt);



	return err;

}
@@ -3020,159 +3220,44 @@ void give_up_console(const struct consw *csw) 
	unregister_con_driver(csw);

}



/*

 * this function is intended to be called by the tty layer only

 */

int vt_bind(int index)

static int __init vtconsole_class_init(void)

{

	const struct consw *defcsw = NULL, *csw = NULL;

	struct con_driver *con;

	int i, more = 1, first = -1, last = -1, deflt = 0;



	if (index >= MAX_NR_CON_DRIVER)

		goto err;



	con = &registered_con_driver[index];



 	if (!con->con || !(con->flag & CON_DRIVER_FLAG_BIND))

		goto err;

	int i;



	csw = con->con;

	vtconsole_class = class_create(THIS_MODULE, "vtconsole");

	if (IS_ERR(vtconsole_class)) {

		printk(KERN_WARNING "Unable to create vt console class; "

		       "errno = %ld\n", PTR_ERR(vtconsole_class));

		vtconsole_class = NULL;

	}



	/* Add system drivers to sysfs */

	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {

		struct con_driver *con = &registered_con_driver[i];



		if (con->con && !(con->flag & CON_DRIVER_FLAG_BIND)) {

			defcsw = con->con;

			break;

		}

	}



	if (!defcsw)

		goto err;



	while (more) {

		more = 0;



		for (i = con->first; i <= con->last; i++) {

			if (con_driver_map[i] == defcsw) {

				if (first == -1)

					first = i;

				last = i;

				more = 1;

			} else if (first != -1)

				break;

		}



		if (first == 0 && last == MAX_NR_CONSOLES -1)

			deflt = 1;



		if (first != -1)

			bind_con_driver(csw, first, last, deflt);



		first = -1;

		last = -1;

		deflt = 0;

	}



err:

	return 0;

		if (con->con && !con->class_dev) {

			con->class_dev =

				class_device_create(vtconsole_class, NULL,

						    MKDEV(0, con->node), NULL,

						    "vtcon%i", con->node);



			if (IS_ERR(con->class_dev)) {

				printk(KERN_WARNING "Unable to create "

				       "class_device for %s; errno = %ld\n",

				       con->desc, PTR_ERR(con->class_dev));

				con->class_dev = NULL;

			} else {

				vtconsole_init_class_device(con);

			}



/*

 * this function is intended to be called by the tty layer only

 */

int vt_unbind(int index)

{

	const struct consw *csw = NULL;

	struct con_driver *con;

	int i, more = 1, first = -1, last = -1, deflt = 0;



	if (index >= MAX_NR_CON_DRIVER)

		goto err;



	con = &registered_con_driver[index];



 	if (!con->con || !(con->flag & CON_DRIVER_FLAG_BIND))

		goto err;



	csw = con->con;



	while (more) {

		more = 0;



		for (i = con->first; i <= con->last; i++) {

			if (con_driver_map[i] == csw) {

				if (first == -1)

					first = i;

				last = i;

				more = 1;

			} else if (first != -1)

				break;

		}



		if (first == 0 && last == MAX_NR_CONSOLES -1)

			deflt = 1;



		if (first != -1)

			unbind_con_driver(csw, first, last, deflt);



		first = -1;

		last = -1;

		deflt = 0;

	}



err:

	return 0;

}

#else

int vt_bind(int index)

{

	return 0;

}

postcore_initcall(vtconsole_class_init);



int vt_unbind(int index)

{

	return 0;

}

#endif



/*

 * this function is intended to be called by the tty layer only

 */

int vt_show_drivers(char *buf)

{

	int i, j, read, offset = 0, cnt = PAGE_SIZE;



	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {

		struct con_driver *con_driver = &registered_con_driver[i];



		if (con_driver->con != NULL) {

			int sys = 0;



			if (con_driver->flag & CON_DRIVER_FLAG_BIND) {

				sys = 2;



				for (j = 0; j < MAX_NR_CONSOLES; j++) {

					if (con_driver_map[j] ==

					    con_driver->con) {

						sys = 1;

						break;

					}

				}

			}



			read = snprintf(buf + offset, cnt, "%i %s: %s\n",

					i, (sys) ? ((sys == 1) ? "B" : "U") :

					"S", con_driver->desc);

			offset += read;

			cnt -= read;

		}

	}



	return offset;

}



/*

 *	Screen blanking

 */