#if 0
#
/bin/sh << EOS
MODNAME=\`basename "$0" .c\`
set -x
gcc -O -fbuiltin -fomit-frame-pointer -fPIC -shared -o \$MODNAME.so "$0" -ldl
EOS
exit
#
#endif

#ifndef __linux
# error "Linux only"
#endif

#define _LIBC
#define _LIBC_REENTRANT
#include <errno.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <dlfcn.h>
#include <scsi/sg.h>
#include <linux/cdrom.h>

#ifdef __GNU_LIBRARY__
# if __GNU_LIBRARY__==6
#  define LIBC_SO	"libc.so.6"
# else
#  define LIBC_SO	"libc.so.5"
# endif
#else
# error "what's your libc?"
#endif

static int (*__libc_ioctl)(int f, int request, ...);

asm ("
.section	\".init\"
	call	_dev_cdrom_init
");

static _dev_cdrom_init()
{ char *env;
  uid_t uid;   
  void *libh;

    if (!(libh = dlopen (LIBC_SO,RTLD_LAZY)))
    {	fprintf (stderr,"can't dlopen(\"%s\").",LIBC_SO);
	exit (1);
    }

    if (!(__libc_ioctl = (int (*)(int,int,...))dlsym (libh,"ioctl")))
    {	fprintf (stderr,"can't link to \"ioctl\" from %s",LIBC_SO);
	exit (1);
    }

}

static int _lntox(unsigned char *p,int n,char *s)
{ static char conv[]="0123456789ABCDEF";
  int i;
    for (i=0;i<n;i++,p++,s+=3)
        s[0]=conv[(p[0]>>4)&0xF], s[1]=conv[p[0]&0xF], s[2]=' ';
  return n*3;
}

static int my_ioctl (const void *ra,int fd,int request,void *p)
{ int ret,len;
  unsigned char c;
  static char out[128];

#if 1
    if (request == SG_IO)
    { struct sg_io_hdr *arg=(struct sg_io_hdr *)p;

    	ret=(*__libc_ioctl)(fd,request,arg);
	c=arg->cmdp[0];
	if (c!=0x28	/* READ(10)		*/
	    && c!=0x2A	/* WRITE(10)		*/
	    && c!=0x00	/* TEST UNIT READY	*/
	    && c!=0x4A	/* GET NOTIFICATION	*/
	    && c!=0x1E	/* PREVENT REMOVAL	*/
	    && c!=0x5C	/* READ BUFFER CAPACITY	*/
	   )
	{  len=_lntox(arg->cmdp,10,out);
	   if (arg->dxfer_direction != SG_DXFER_NONE)
	   {   out[len-1]=arg->dxfer_direction&1?'<':'>';
	       len+=_lntox(arg->dxferp,arg->dxfer_len>16?16:arg->dxfer_len,out+len);
	       out[len++]='\n'; out[len]='\0';
	   }
	   else
	   {   out[len++]='\n';out[len]='\0';   }
	   write(2,out,len);
	}

        return ret;
    }
    else if (request == CDROM_SEND_PACKET)
    { struct cdrom_generic_command *arg=(struct cdrom_generic_command *)p;

    	ret=(*__libc_ioctl)(fd,request,arg);
	c=arg->cmd[0];
	if (c!=0x28	/* READ(10)		*/
	    && c!=0x2A	/* WRITE(10)		*/
	    && c!=0x00	/* TEST UNIT READY	*/
	    && c!=0x4A	/* GET NOTIFICATION	*/
	    && c!=0x1E	/* PREVENT REMOVAL	*/
	    && c!=0x5C	/* READ BUFFER CAPACITY	*/
	   )
	{  len=_lntox(arg->cmd,10,out);
	   if (arg->data_direction != CGC_DATA_NONE)
	   {   out[len-1]=arg->data_direction&1?'>':'<';
	       len+=_lntox(arg->buffer,arg->buflen>16?16:arg->buflen,out+len);
	       out[len++]='\n'; out[len]='\0';
	   }
	   else
	   {   out[len++]='\n';out[len]='\0';   }
	   write(2,out,len);
	}

        return ret;
    }
#endif

  return -38;
}

asm ("
.text
.type   ioctl,@function
.global ioctl
.align  4
ioctl:
        call    my_ioctl
        cmpl    $-38,%eax
        jne     1f
        jmp     *__libc_ioctl
1:      ret
.size   ioctl,.-ioctl
");