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 <linux/uaccess.h> 18 #include <asm/io.h> 19 20 extern wait_queue_head_t log_wait; 21 22 static int kmsg_open(struct inode * inode, struct file * file) 23 { 24 return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC); 25 } 26 27 static int kmsg_release(struct inode * inode, struct file * file) 28 { 29 (void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_PROC); 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 { 36 if ((file->f_flags & O_NONBLOCK) && 37 !do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC)) 38 return -EAGAIN; 39 return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_PROC); 40 } 41 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_PROC)) 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 59 static int __init proc_kmsg_init(void) 60 { 61 proc_create("kmsg", S_IRUSR, NULL, &proc_kmsg_operations); 62 return 0; 63 } 64 fs_initcall(proc_kmsg_init); 65