#include <linux/module.h>
#include <linux/init.h>
#include <linux/relay.h>
#include <linux/debugfs.h>

static char *TEXT="hello world\n";
static struct rchan *channel_id;
static struct dentry *logdir;

static int lremove_buf_file(struct dentry *dentry)
{
  debugfs_remove(dentry);
  return 0;
}

static struct dentry *lcreate_buf_file(const char *filename,
				       struct dentry *parent, int mode, struct rchan_buf *buf, int *is_global)
{
  return debugfs_create_file(filename, mode, parent, buf,
			     &relay_file_operations);
}

static int lsubbuf_start(struct rchan_buf *buf, void *subbuf, void *prev_subbuf,
			 unsigned int prev_padding)
{
  return 1; // bufferchange can occur
}

struct rchan_callbacks cb = {
  subbuf_start:  lsubbuf_start,
  create_buf_file: lcreate_buf_file,
  remove_buf_file: lremove_buf_file,
};

static int __init mod_init(void)
{
  int i;

  logdir = debugfs_create_dir("relay", NULL);
  if( logdir==NULL ) {
    return -EIO;
  }

  channel_id = relay_open( "logfile", logdir, 32, 4, &cb );
  for( i=0; i<20; i++ ) { // Probehalber fuellen wir die Buffer
    relay_write( channel_id, TEXT, strlen(TEXT)+1 );
  }
  return 0;
}

static void __exit mod_exit(void)
{
  relay_close( channel_id );
  debugfs_remove( logdir );
}

module_init( mod_init );
module_exit( mod_exit );

MODULE_LICENSE("GPL");