linux-imx

// 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;