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// 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_NBCON, 'N' },
{ 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->flags & CON_NBCON) || 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)
__acquires(&console_mutex)
{
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)
__releases(&console_mutex)
{
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);
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