cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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kmsg.c (1561B)

      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
     21extern wait_queue_head_t log_wait;
     22
     23static int kmsg_open(struct inode * inode, struct file * file)
     24{
     25	return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC);
     26}
     27
     28static 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
     34static 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
     43static __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
     52static 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
     61static int __init proc_kmsg_init(void)
     62{
     63	proc_create("kmsg", S_IRUSR, NULL, &kmsg_proc_ops);
     64	return 0;
     65}
     66fs_initcall(proc_kmsg_init);