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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
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> | |
ae048112 | 14 | #include <linux/proc_fs.h> |
1da177e4 | 15 | #include <linux/fs.h> |
00234592 | 16 | #include <linux/syslog.h> |
1da177e4 | 17 | |
1da177e4 LT |
18 | #include <asm/io.h> |
19 | ||
20 | extern wait_queue_head_t log_wait; | |
21 | ||
1da177e4 LT |
22 | static int kmsg_open(struct inode * inode, struct file * file) |
23 | { | |
637241a9 | 24 | return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC); |
1da177e4 LT |
25 | } |
26 | ||
27 | static int kmsg_release(struct inode * inode, struct file * file) | |
28 | { | |
637241a9 | 29 | (void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_PROC); |
1da177e4 LT |
30 | return 0; |
31 | } | |
32 | ||
33 | static ssize_t kmsg_read(struct file *file, char __user *buf, | |
34 | size_t count, loff_t *ppos) | |
35 | { | |
00234592 | 36 | if ((file->f_flags & O_NONBLOCK) && |
637241a9 | 37 | !do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC)) |
1da177e4 | 38 | return -EAGAIN; |
637241a9 | 39 | return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_PROC); |
1da177e4 LT |
40 | } |
41 | ||
076ccb76 | 42 | static __poll_t kmsg_poll(struct file *file, poll_table *wait) |
1da177e4 LT |
43 | { |
44 | poll_wait(file, &log_wait, wait); | |
637241a9 | 45 | if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC)) |
a9a08845 | 46 | return EPOLLIN | EPOLLRDNORM; |
1da177e4 LT |
47 | return 0; |
48 | } | |
49 | ||
50 | ||
97a32539 | 51 | static const struct proc_ops kmsg_proc_ops = { |
d919b33d | 52 | .proc_flags = PROC_ENTRY_PERMANENT, |
97a32539 AD |
53 | .proc_read = kmsg_read, |
54 | .proc_poll = kmsg_poll, | |
55 | .proc_open = kmsg_open, | |
56 | .proc_release = kmsg_release, | |
57 | .proc_lseek = generic_file_llseek, | |
1da177e4 | 58 | }; |
ae048112 AD |
59 | |
60 | static int __init proc_kmsg_init(void) | |
61 | { | |
97a32539 | 62 | proc_create("kmsg", S_IRUSR, NULL, &kmsg_proc_ops); |
ae048112 AD |
63 | return 0; |
64 | } | |
abaf3787 | 65 | fs_initcall(proc_kmsg_init); |