console: add /proc/consoles (23308ba5) · Commits · 戴 / test

Documentation/filesystems/proc.txt

+24 −0

Original line number	Diff line number	Diff line
		@@ -1181,6 +1181,30 @@ Table 1-12: Files in /proc/fs/ext4/<devname>
		mb_groups details of multiblock allocator buddy cache of free blocks
		..............................................................................

		2.0 /proc/consoles
		------------------
		Shows registered system console lines.

		To see which character device lines are currently used for the system console
		/dev/console, you may simply look into the file /proc/consoles:

		> cat /proc/consoles
		tty0 -WU (ECp) 4:7
		ttyS0 -W- (Ep) 4:64

		The columns are:

		device name of the device
		operations R = can do read operations
		W = can do write operations
		U = can do unblank
		flags E = it is enabled
		C = it is prefered console
		B = it is primary boot console
		p = it is used for printk buffer
		b = it is not a TTY but a Braille device
		a = it is safe to use when cpu is offline
		major:minor major and minor number of the device separated by a colon

		------------------------------------------------------------------------------
		Summary

fs/proc/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@ proc-y += devices.o
		proc-y += interrupts.o
		proc-y += loadavg.o
		proc-y += meminfo.o
		proc-y += proc_console.o
		proc-y += stat.o
		proc-y += uptime.o
		proc-y += version.o

fs/proc/proc_console.c

0 → 100644

+114 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (c) 2010 Werner Fink, Jiri Slaby
		*
		* Licensed under GPLv2
		*/

		#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;
		int len;
		dev_t dev = 0;

		if (con->device) {
		const struct tty_driver *driver;
		int index;
		driver = con->device(con, &index);
		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_printf(m, "%s%d%n", con->name, con->index, &len);
		len = 21 - len;
		if (len < 1)
		len = 1;
		seq_printf(m, "%*c%c%c%c (%s)", len, ' ', con->read ? 'R' : '-',
		con->write ? 'W' : '-', con->unblank ? 'U' : '-',
		flags);
		if (dev)
		seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));

		seq_printf(m, "\n");

		return 0;
		}

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

		acquire_console_sem();
		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 con->next;
		}

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

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

		static int consoles_open(struct inode inode, struct file file)
		{
		return seq_open(file, &consoles_op);
		}

		static const struct file_operations proc_consoles_operations = {
		.open = consoles_open,
		.read = seq_read,
		.llseek = seq_lseek,
		.release = seq_release,
		};

		static int register_proc_consoles(void)
		{
		proc_create("consoles", 0, NULL, &proc_consoles_operations);
		return 0;
		}
		module_init(register_proc_consoles);

Admin message