[linux-block.git] / fs / proc / consoles.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2010 Werner Fink, Jiri Slaby
 */

#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/tty_driver.h>

/*
 * This is handler for /proc/consoles
 */
static int show_console_dev(struct seq_file *m, void *v)
{
	static const struct {
		short flag;
		char name;
	} con_flags[] = {
		{ CON_ENABLED,		'E' },
		{ CON_CONSDEV,		'C' },
		{ CON_BOOT,		'B' },
		{ CON_PRINTBUFFER,	'p' },
		{ CON_BRL,		'b' },
		{ CON_ANYTIME,		'a' },
	};
	char flags[ARRAY_SIZE(con_flags) + 1];
	struct console *con = v;
	unsigned int a;
	dev_t dev = 0;

	if (con->device) {
		const struct tty_driver *driver;
		int index;

		/*
		 * Take console_lock to serialize device() callback with
		 * other console operations. For example, fg_console is
		 * modified under console_lock when switching vt.
		 */
		console_lock();
		driver = con->device(con, &index);
		console_unlock();

		if (driver) {
			dev = MKDEV(driver->major, driver->minor_start);
			dev += index;
		}
	}

	for (a = 0; a < ARRAY_SIZE(con_flags); a++)
		flags[a] = (con->flags & con_flags[a].flag) ?
			con_flags[a].name : ' ';
	flags[a] = 0;

	seq_setwidth(m, 21 - 1);
	seq_printf(m, "%s%d", con->name, con->index);
	seq_pad(m, ' ');
	seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
			con->write ? 'W' : '-', con->unblank ? 'U' : '-',
			flags);
	if (dev)
		seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));

	seq_putc(m, '\n');
	return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	struct console *con;
	loff_t off = 0;

	/*
	 * Hold the console_list_lock to guarantee safe traversal of the
	 * console list. SRCU cannot be used because there is no
	 * place to store the SRCU cookie.
	 */
	console_list_lock();
	for_each_console(con)
		if (off++ == *pos)
			break;

	return con;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct console *con = v;

	++*pos;
	return hlist_entry_safe(con->node.next, struct console, node);
}

static void c_stop(struct seq_file *m, void *v)
{
	console_list_unlock();
}

static const struct seq_operations consoles_op = {
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= show_console_dev
};

static int __init proc_consoles_init(void)
{
	proc_create_seq("consoles", 0, NULL, &consoles_op);
	return 0;
}
fs_initcall(proc_consoles_init);
Commit	Line	Data
f50a7f3d	1	// SPDX-License-Identifier: GPL-2.0-only
23308ba5 JS	2	/*
23308ba5 JS	3	* Copyright (c) 2010 Werner Fink, Jiri Slaby
23308ba5 JS	4	*/
	5
	6	#include <linux/console.h>
	7	#include <linux/kernel.h>
	8	#include <linux/proc_fs.h>
	9	#include <linux/seq_file.h>
	10	#include <linux/tty_driver.h>
	11
	12	/*
	13	* This is handler for /proc/consoles
	14	*/
	15	static int show_console_dev(struct seq_file m, void v)
	16	{
	17	static const struct {
	18	short flag;
	19	char name;
	20	} con_flags[] = {
	21	{ CON_ENABLED, 'E' },
	22	{ CON_CONSDEV, 'C' },
	23	{ CON_BOOT, 'B' },
	24	{ CON_PRINTBUFFER, 'p' },
	25	{ CON_BRL, 'b' },
	26	{ CON_ANYTIME, 'a' },
	27	};
	28	char flags[ARRAY_SIZE(con_flags) + 1];
	29	struct console *con = v;
	30	unsigned int a;
23308ba5 JS	31	dev_t dev = 0;
	32
	33	if (con->device) {
	34	const struct tty_driver *driver;
	35	int index;
28de287a JO	36
	37	/*
	38	* Take console_lock to serialize device() callback with
	39	* other console operations. For example, fg_console is
	40	* modified under console_lock when switching vt.
	41	*/
	42	console_lock();
23308ba5	43	driver = con->device(con, &index);
28de287a JO	44	console_unlock();
28de287a JO	45
23308ba5 JS	46	if (driver) {
	47	dev = MKDEV(driver->major, driver->minor_start);
	48	dev += index;
	49	}
	50	}
	51
	52	for (a = 0; a < ARRAY_SIZE(con_flags); a++)
	53	flags[a] = (con->flags & con_flags[a].flag) ?
	54	con_flags[a].name : ' ';
	55	flags[a] = 0;
	56
652586df TH	57	seq_setwidth(m, 21 - 1);
	58	seq_printf(m, "%s%d", con->name, con->index);
	59	seq_pad(m, ' ');
	60	seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
23308ba5 JS	61	con->write ? 'W' : '-', con->unblank ? 'U' : '-',
	62	flags);
	63	if (dev)
	64	seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));
	65
4bf8ba81	66	seq_putc(m, '\n');
23308ba5 JS	67	return 0;
	68	}
	69
	70	static void c_start(struct seq_file m, loff_t *pos)
	71	{
	72	struct console *con;
	73	loff_t off = 0;
	74
8b5dd400	75	/*
28de287a	76	* Hold the console_list_lock to guarantee safe traversal of the
8b5dd400 JO	77	* console list. SRCU cannot be used because there is no
	78	* place to store the SRCU cookie.
	79	*/
28de287a	80	console_list_lock();
23308ba5 JS	81	for_each_console(con)
	82	if (off++ == *pos)
	83	break;
	84
	85	return con;
	86	}
	87
	88	static void c_next(struct seq_file m, void v, loff_t pos)
	89	{
	90	struct console *con = v;
d9a4af56	91
23308ba5	92	++*pos;
d9a4af56	93	return hlist_entry_safe(con->node.next, struct console, node);
23308ba5 JS	94	}
	95
	96	static void c_stop(struct seq_file m, void v)
	97	{
28de287a	98	console_list_unlock();
23308ba5 JS	99	}
	100
	101	static const struct seq_operations consoles_op = {
	102	.start = c_start,
	103	.next = c_next,
	104	.stop = c_stop,
	105	.show = show_console_dev
	106	};
	107
bf33cbdf	108	static int __init proc_consoles_init(void)
23308ba5	109	{
fddda2b7	110	proc_create_seq("consoles", 0, NULL, &consoles_op);
23308ba5 JS	111	return 0;
23308ba5 JS	112	}
abaf3787	113	fs_initcall(proc_consoles_init);