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

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/proc/kmsg.c
 *
 *  Copyright (C) 1992  by Linus Torvalds
 *
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/fs.h>
#include <linux/syslog.h>

#include <linux/uaccess.h>
#include <asm/io.h>

extern wait_queue_head_t log_wait;

static int kmsg_open(struct inode * inode, struct file * file)
{
	return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC);
}

static int kmsg_release(struct inode * inode, struct file * file)
{
	(void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_PROC);
	return 0;
}

static ssize_t kmsg_read(struct file *file, char __user *buf,
			 size_t count, loff_t *ppos)
{
	if ((file->f_flags & O_NONBLOCK) &&
	    !do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
		return -EAGAIN;
	return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_PROC);
}

static __poll_t kmsg_poll(struct file *file, poll_table *wait)
{
	poll_wait(file, &log_wait, wait);
	if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
		return EPOLLIN | EPOLLRDNORM;
	return 0;
}


static const struct proc_ops kmsg_proc_ops = {
	.proc_flags	= PROC_ENTRY_PERMANENT,
	.proc_read	= kmsg_read,
	.proc_poll	= kmsg_poll,
	.proc_open	= kmsg_open,
	.proc_release	= kmsg_release,
	.proc_lseek	= generic_file_llseek,
};

static int __init proc_kmsg_init(void)
{
	proc_create("kmsg", S_IRUSR, NULL, &kmsg_proc_ops);
	return 0;
}
fs_initcall(proc_kmsg_init);
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* linux/fs/proc/kmsg.c
	4	*
	5	* Copyright (C) 1992 by Linus Torvalds
	6	*
	7	*/
	8
	9	#include <linux/types.h>
	10	#include <linux/errno.h>
	11	#include <linux/time.h>
	12	#include <linux/kernel.h>
	13	#include <linux/poll.h>
	14	#include <linux/proc_fs.h>
	15	#include <linux/fs.h>
	16	#include <linux/syslog.h>
	17
	18	#include <linux/uaccess.h>
	19	#include <asm/io.h>
	20
	21	extern wait_queue_head_t log_wait;
	22
	23	static int kmsg_open(struct inode * inode, struct file * file)
	24	{
	25	return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC);
	26	}
	27
	28	static int kmsg_release(struct inode * inode, struct file * file)
	29	{
	30	(void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_PROC);
	31	return 0;
	32	}
	33
	34	static ssize_t kmsg_read(struct file file, char __user buf,
	35	size_t count, loff_t *ppos)
	36	{
	37	if ((file->f_flags & O_NONBLOCK) &&
	38	!do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
	39	return -EAGAIN;
	40	return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_PROC);
	41	}
	42
	43	static __poll_t kmsg_poll(struct file file, poll_table wait)
	44	{
	45	poll_wait(file, &log_wait, wait);
	46	if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
	47	return EPOLLIN \| EPOLLRDNORM;
	48	return 0;
	49	}
	50
	51
	52	static const struct proc_ops kmsg_proc_ops = {
	53	.proc_flags = PROC_ENTRY_PERMANENT,
	54	.proc_read = kmsg_read,
	55	.proc_poll = kmsg_poll,
	56	.proc_open = kmsg_open,
	57	.proc_release = kmsg_release,
	58	.proc_lseek = generic_file_llseek,
	59	};
	60
	61	static int __init proc_kmsg_init(void)
	62	{
	63	proc_create("kmsg", S_IRUSR, NULL, &kmsg_proc_ops);
	64	return 0;
	65	}
	66	fs_initcall(proc_kmsg_init);