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 extern wait_queue_head_t log_wait;
  19
  20 extern int do_syslog(int type, char __user *bug, int count);
  21
  22 static int kmsg_open(struct inode * inode, struct file * file)
  23 {
  24         return do_syslog(1,NULL,0);
  25 }
  26
  27 static int kmsg_release(struct inode * inode, struct file * file)
  28 {
  29         (void) do_syslog(0,NULL,0);
  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) && !do_syslog(9, NULL, 0))
  37                 return -EAGAIN;
  38         return do_syslog(2, buf, count);
  39 }
  40
  41 static unsigned int kmsg_poll(struct file *file, poll_table *wait)
  42 {
  43         poll_wait(file, &log_wait, wait);
  44         if (do_syslog(9, NULL, 0))
  45                 return POLLIN | POLLRDNORM;
  46         return 0;
  47 }
  48
  49
  50 const struct file_operations proc_kmsg_operations = {
  51         .read           = kmsg_read,
  52         .poll           = kmsg_poll,
  53         .open           = kmsg_open,
  54         .release        = kmsg_release,
  55 };