117 lines
2.5 KiB
C
117 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2010 Werner Fink, Jiri Slaby
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*/
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#include <linux/console.h>
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#include <linux/kernel.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/tty_driver.h>
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/*
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* This is handler for /proc/consoles
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*/
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static int show_console_dev(struct seq_file *m, void *v)
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{
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static const struct {
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short flag;
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char name;
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} con_flags[] = {
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{ CON_ENABLED, 'E' },
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{ CON_CONSDEV, 'C' },
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{ CON_BOOT, 'B' },
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{ CON_NBCON, 'N' },
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{ CON_PRINTBUFFER, 'p' },
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{ CON_BRL, 'b' },
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{ CON_ANYTIME, 'a' },
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};
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char flags[ARRAY_SIZE(con_flags) + 1];
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struct console *con = v;
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unsigned int a;
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dev_t dev = 0;
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if (con->device) {
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const struct tty_driver *driver;
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int index;
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/*
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* Take console_lock to serialize device() callback with
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* other console operations. For example, fg_console is
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* modified under console_lock when switching vt.
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*/
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console_lock();
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driver = con->device(con, &index);
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console_unlock();
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if (driver) {
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dev = MKDEV(driver->major, driver->minor_start);
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dev += index;
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}
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}
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for (a = 0; a < ARRAY_SIZE(con_flags); a++)
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flags[a] = (con->flags & con_flags[a].flag) ?
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con_flags[a].name : ' ';
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flags[a] = 0;
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seq_setwidth(m, 21 - 1);
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seq_printf(m, "%s%d", con->name, con->index);
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seq_pad(m, ' ');
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seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
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((con->flags & CON_NBCON) || con->write) ? 'W' : '-',
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con->unblank ? 'U' : '-', flags);
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if (dev)
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seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));
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seq_putc(m, '\n');
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return 0;
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}
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static void *c_start(struct seq_file *m, loff_t *pos)
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__acquires(&console_mutex)
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{
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struct console *con;
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loff_t off = 0;
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/*
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* Hold the console_list_lock to guarantee safe traversal of the
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* console list. SRCU cannot be used because there is no
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* place to store the SRCU cookie.
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*/
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console_list_lock();
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for_each_console(con)
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if (off++ == *pos)
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break;
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return con;
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}
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static void *c_next(struct seq_file *m, void *v, loff_t *pos)
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{
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struct console *con = v;
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++*pos;
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return hlist_entry_safe(con->node.next, struct console, node);
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}
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static void c_stop(struct seq_file *m, void *v)
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__releases(&console_mutex)
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{
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console_list_unlock();
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}
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static const struct seq_operations consoles_op = {
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.start = c_start,
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.next = c_next,
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.stop = c_stop,
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.show = show_console_dev
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};
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static int __init proc_consoles_init(void)
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{
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proc_create_seq("consoles", 0, NULL, &consoles_op);
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return 0;
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}
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fs_initcall(proc_consoles_init);
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