fs/proc/kmsg.c

   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/fs.h>
  14
  15 #include <asm/uaccess.h>
  16 #include <asm/io.h>
  17
  18 #include "internal.h"
  19
  20 extern wait_queue_head_t log_wait;
  21
  22 extern int do_syslog(int type, char __user *bug, int count);
  23
  24 static int kmsg_open(struct inode * inode, struct file * file)
  25 {
  26         return do_syslog(1,NULL,0);
  27 }
  28
  29 static int kmsg_release(struct inode * inode, struct file * file)
  30 {
  31         (void) do_syslog(0,NULL,0);
  32         return 0;
  33 }
  34
  35 static ssize_t kmsg_read(struct file *file, char __user *buf,
  36                          size_t count, loff_t *ppos)
  37 {
  38         if ((file->f_flags & O_NONBLOCK) && !do_syslog(9, NULL, 0))
  39                 return -EAGAIN;
  40         return do_syslog(2, buf, count);
  41 }
  42
  43 static unsigned int kmsg_poll(struct file *file, poll_table *wait)
  44 {
  45         poll_wait(file, &log_wait, wait);
  46         if (do_syslog(9, NULL, 0))
  47                 return POLLIN | POLLRDNORM;
  48         return 0;
  49 }
  50
  51
  52 const struct file_operations proc_kmsg_operations = {
  53         .read           = kmsg_read,
  54         .poll           = kmsg_poll,
  55         .open           = kmsg_open,
  56         .release        = kmsg_release,
  57 };