1 /*
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>
13 #include <linux/proc_fs.h>
14 #include <linux/fs.h>
15 #include <linux/syslog.h>
16
17 #include <asm/uaccess.h>
18 #include <asm/io.h>
19
20 extern wait_queue_head_t log_wait;
21
kmsg_open(struct inode * inode,struct file * file)22 static int kmsg_open(struct inode * inode, struct file * file)
23 {
24 return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_FILE);
25 }
26
kmsg_release(struct inode * inode,struct file * file)27 static int kmsg_release(struct inode * inode, struct file * file)
28 {
29 (void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_FILE);
30 return 0;
31 }
32
kmsg_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)33 static ssize_t kmsg_read(struct file *file, char __user *buf,
34 size_t count, loff_t *ppos)
35 {
36 if ((file->f_flags & O_NONBLOCK) &&
37 !do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_FILE))
38 return -EAGAIN;
39 return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_FILE);
40 }
41
kmsg_poll(struct file * file,poll_table * wait)42 static unsigned int kmsg_poll(struct file *file, poll_table *wait)
43 {
44 poll_wait(file, &log_wait, wait);
45 if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_FILE))
46 return POLLIN | POLLRDNORM;
47 return 0;
48 }
49
50
51 static const struct file_operations proc_kmsg_operations = {
52 .read = kmsg_read,
53 .poll = kmsg_poll,
54 .open = kmsg_open,
55 .release = kmsg_release,
56 .llseek = generic_file_llseek,
57 };
58
proc_kmsg_init(void)59 static int __init proc_kmsg_init(void)
60 {
61 proc_create("kmsg", S_IRUSR, NULL, &proc_kmsg_operations);
62 return 0;
63 }
64 module_init(proc_kmsg_init);
65