Commit 6db4063c authored by Antonino A. Daplas's avatar Antonino A. Daplas Committed by Linus Torvalds

[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
......@@ -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;
}
/*
* 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 (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);
}
}
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
*/
......
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