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authorKay Sievers <kay.sievers@vrfy.org>2010-12-01 18:51:05 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2010-12-16 16:15:34 -0800
commitfbc92a3455577ab17615cbcb91826399061bd789 (patch)
tree0f47703d9d3b40969e007a6d27a1b603cdff43da /drivers/tty
parent35c64e5d13c3d7d8c4ad061ad5e20498b9160c24 (diff)
tty: add 'active' sysfs attribute to tty0 and console device
tty: add 'active' sysfs attribute to tty0 and console device Userspace can query the actual virtual console, and the configured console devices behind /dev/tt0 and /dev/console. The last entry in the list of devices is the active device, analog to the console= kernel command line option. The attribute supports poll(), which is raised when the virtual console is changed or /dev/console is reconfigured. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> index 0000000..b138b66
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/tty_io.c47
-rw-r--r--drivers/tty/vt/vt.c23
2 files changed, 65 insertions, 5 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index c05c5af5aa04..be5ab4ac0b93 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3232,9 +3232,45 @@ static int __init tty_class_init(void)
postcore_initcall(tty_class_init);
/* 3/2004 jmc: why do these devices exist? */
-
static struct cdev tty_cdev, console_cdev;
+static ssize_t show_cons_active(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct console *cs[16];
+ int i = 0;
+ struct console *c;
+ ssize_t count = 0;
+
+ acquire_console_sem();
+ for (c = console_drivers; c; c = c->next) {
+ if (!c->device)
+ continue;
+ if (!c->write)
+ continue;
+ if ((c->flags & CON_ENABLED) == 0)
+ continue;
+ cs[i++] = c;
+ if (i >= ARRAY_SIZE(cs))
+ break;
+ }
+ while (i--)
+ count += sprintf(buf + count, "%s%d%c",
+ cs[i]->name, cs[i]->index, i ? ' ':'\n');
+ release_console_sem();
+
+ return count;
+}
+static DEVICE_ATTR(active, S_IRUGO, show_cons_active, NULL);
+
+static struct device *consdev;
+
+void console_sysfs_notify(void)
+{
+ if (consdev)
+ sysfs_notify(&consdev->kobj, NULL, "active");
+}
+
/*
* Ok, now we can initialize the rest of the tty devices and can count
* on memory allocations, interrupts etc..
@@ -3245,15 +3281,18 @@ int __init tty_init(void)
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)
panic("Couldn't register /dev/tty driver\n");
- device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL,
- "tty");
+ device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty");
cdev_init(&console_cdev, &console_fops);
if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0)
panic("Couldn't register /dev/console driver\n");
- device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
+ consdev = device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL,
"console");
+ if (IS_ERR(consdev))
+ consdev = NULL;
+ else
+ device_create_file(consdev, &dev_attr_active);
#ifdef CONFIG_VT
vty_init(&console_fops);
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index a8ec48ed14d9..76407eca9ab0 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -236,6 +236,14 @@ enum {
};
/*
+ * /sys/class/tty/tty0/
+ *
+ * the attribute 'active' contains the name of the current vc
+ * console and it supports poll() to detect vc switches
+ */
+static struct device *tty0dev;
+
+/*
* Notifier list for console events.
*/
static ATOMIC_NOTIFIER_HEAD(vt_notifier_list);
@@ -688,6 +696,8 @@ void redraw_screen(struct vc_data *vc, int is_switch)
save_screen(old_vc);
set_origin(old_vc);
}
+ if (tty0dev)
+ sysfs_notify(&tty0dev->kobj, NULL, "active");
} else {
hide_cursor(vc);
redraw = 1;
@@ -2967,13 +2977,24 @@ static const struct tty_operations con_ops = {
static struct cdev vc0_cdev;
+static ssize_t show_tty_active(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "tty%d\n", fg_console + 1);
+}
+static DEVICE_ATTR(active, S_IRUGO, show_tty_active, NULL);
+
int __init vty_init(const struct file_operations *console_fops)
{
cdev_init(&vc0_cdev, console_fops);
if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
panic("Couldn't register /dev/tty0 driver\n");
- device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
+ tty0dev = device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0");
+ if (IS_ERR(tty0dev))
+ tty0dev = NULL;
+ else
+ device_create_file(tty0dev, &dev_attr_active);
vcs_init();