blob: bd4b5a740ff1b9de6492f5da9adaf7e500d35b25 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/proc/kmsg.c
3 *
4 * Copyright (C) 1992 by Linus Torvalds
5 *
6 */
7
8#include <linux/types.h>
9#include <linux/errno.h>
10#include <linux/time.h>
11#include <linux/kernel.h>
12#include <linux/poll.h>
Alexey Dobriyanae048112008-10-04 14:39:12 +040013#include <linux/proc_fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/fs.h>
Kees Cook00234592010-02-03 15:36:43 -080015#include <linux/syslog.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
17#include <asm/uaccess.h>
18#include <asm/io.h>
19
20extern wait_queue_head_t log_wait;
21
Linus Torvalds1da177e2005-04-16 15:20:36 -070022static int kmsg_open(struct inode * inode, struct file * file)
23{
Kees Cookd78ca3c2010-02-03 15:37:13 -080024 return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_FILE);
Linus Torvalds1da177e2005-04-16 15:20:36 -070025}
26
27static int kmsg_release(struct inode * inode, struct file * file)
28{
Kees Cookd78ca3c2010-02-03 15:37:13 -080029 (void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_FILE);
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 return 0;
31}
32
33static ssize_t kmsg_read(struct file *file, char __user *buf,
34 size_t count, loff_t *ppos)
35{
Kees Cook00234592010-02-03 15:36:43 -080036 if ((file->f_flags & O_NONBLOCK) &&
Kees Cookd78ca3c2010-02-03 15:37:13 -080037 !do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_FILE))
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 return -EAGAIN;
Kees Cookd78ca3c2010-02-03 15:37:13 -080039 return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_FILE);
Linus Torvalds1da177e2005-04-16 15:20:36 -070040}
41
42static unsigned int kmsg_poll(struct file *file, poll_table *wait)
43{
44 poll_wait(file, &log_wait, wait);
Kees Cookd78ca3c2010-02-03 15:37:13 -080045 if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_FILE))
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 return POLLIN | POLLRDNORM;
47 return 0;
48}
49
50
Alexey Dobriyanae048112008-10-04 14:39:12 +040051static const struct file_operations proc_kmsg_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070052 .read = kmsg_read,
53 .poll = kmsg_poll,
54 .open = kmsg_open,
55 .release = kmsg_release,
Frederic Weisbecker41775e22010-03-30 02:24:54 +020056 .llseek = generic_file_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -070057};
Alexey Dobriyanae048112008-10-04 14:39:12 +040058
59static int __init proc_kmsg_init(void)
60{
61 proc_create("kmsg", S_IRUSR, NULL, &proc_kmsg_operations);
62 return 0;
63}
64module_init(proc_kmsg_init);