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// 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 file_operations proc_kmsg_operations = {
.read = kmsg_read,
.poll = kmsg_poll,
.open = kmsg_open,
.release = kmsg_release,
.llseek = generic_file_llseek,
};
static int __init proc_kmsg_init(void)
{
proc_create("kmsg", S_IRUSR, NULL, &proc_kmsg_operations);
return 0;
}
fs_initcall(proc_kmsg_init);
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