Toggling "eject" and "eject -t"

daihard · 12-25-2004, 03:39 PM

I would like to write a shell script that invokes either "eject" or "eject -t" depending upon the state of my DVD drive tray. I want to place a shortcut of the script so I can click on it to open/close the tray. How can I check the state of the tray from within the script?

Code:

#! /bin/sh

if [ <tray_is_closed> ]; then
    eject
else
    eject -t
fi

Thanks!
Dai

dizzutch · 12-25-2004, 07:07 PM

some pseudocode for ya
write an integer to a file that sets the state of the tray

Code:

read open_closed.txt into open
if [ open == 1] 
eject -t 
write 0 to open_closed.txt
else
eject
write 1 to open_closed.txt

foo_bar_foo · 12-25-2004, 10:14 PM

there is a way to get information in c
int test = (ioctl(fdcdrom, CDROM_DRIVE_STATUS));

but it's limited like it won't just open an empty drive
try this and look at linux/cdrom.h for the rest of the possible return values
i don't think you will get much farther than this -- i tried once -- but i might be wrong

Code:

#include <sys/stat.h>
#include <fcntl.h>
#include <linux/cdrom.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <stdlib.h>

int main() {
  
  int test = 0;
  int fdcdrom = open("/dev/cdrom", O_RDONLY);
		
	
  test = (ioctl(fdcdrom, CDROM_DRIVE_STATUS));
// if it's open close it
  if (test == 2) { 
                 ioctl(fdcdrom, CDROMCLOSETRAY);
                 close(fdcdrom);
                 return 0;
 } else {
// i think here it will only eject if there is a disk !
                 
                 ioctl(fdcdrom, CDROMEJECT);
                 close(fdcdrom);
                 return 0;
          }
}

daihard · 12-27-2004, 03:01 AM

Thanks guys!

I looked at both solutions. It seems like the C program is a better fit for me. Not that there's anything wrong with the first one - it's just that writing the status to a file means I always have to use that script to open/close the tray in order to keep the file content in sync with the actual state of the tray. The C program seems more flexible. I'll try that and see how it goes.

Again, I appreciate both you guys help!

Dai

[EDIT] The C program worked beautifully. The only thing I had to fix was the parameter to the open function. You have to specify O_NONBLOCK in addition to O_RDONLY in order for the ioctl function to work. I'm a happy man!