2000-11-15 18:39:22

by W. Michael Petullo

[permalink] [raw]
Subject: EJECT ioctl fails on empty SCSI CD-ROM

Apparently using the CDROMEJECT ioctl with kernel 2.4-testX fails on
a SCSI CD-ROM that does not have a disc in it. The errno returned
corresponds to the string ``No such file or directory.''

The Linux CD-ROM Standard states that CDROMEJECT opens the drive tray.
It does not mention any prerequisite such as media being present.

Is this the expected behavior? If so, I am curious to hear the rationale
behind it.

Thanks!

--
W. Michael Petullo

:wq


2000-11-15 20:36:59

by James Stevenson

[permalink] [raw]
Subject: Re: EJECT ioctl fails on empty SCSI CD-ROM


Hi

this is what i get on 2.2.17

open("/dev/scd1", O_RDONLY|O_NONBLOCK) = 3
ioctl(3, CDROMEJECT, 0xbffffc78) = 0
close(3) = 0



In local.linux-kernel-list, you wrote:
>Apparently using the CDROMEJECT ioctl with kernel 2.4-testX fails on
>a SCSI CD-ROM that does not have a disc in it. The errno returned
>corresponds to the string ``No such file or directory.''
>
>The Linux CD-ROM Standard states that CDROMEJECT opens the drive tray.
>It does not mention any prerequisite such as media being present.
>
>Is this the expected behavior? If so, I am curious to hear the rationale
>behind it.


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2000-11-15 20:52:52

by Richard B. Johnson

[permalink] [raw]
Subject: Re: EJECT ioctl fails on empty SCSI CD-ROM

On Wed, 15 Nov 2000, James Stevenson wrote:

>
> Hi
>
> this is what i get on 2.2.17
>
> open("/dev/scd1", O_RDONLY|O_NONBLOCK) = 3
> ioctl(3, CDROMEJECT, 0xbffffc78) = 0
> close(3) = 0
>
>

>
> In local.linux-kernel-list, you wrote:
> >Apparently using the CDROMEJECT ioctl with kernel 2.4-testX fails on
> >a SCSI CD-ROM that does not have a disc in it. The errno returned
> >corresponds to the string ``No such file or directory.''
> >
> >The Linux CD-ROM Standard states that CDROMEJECT opens the drive tray.
> >It does not mention any prerequisite such as media being present.
> >
> >Is this the expected behavior? If so, I am curious to hear the rationale
> >behind it.
>

Well the open fails with ENOMEDIUM (errno 123). This is hardly appropriate
since you can't insert any "media" on some machines without a paperclip.

readlink("/dev/cdrom", "", 256) = 9
open("/dev/scd0", O_RDONLY) = -1 ERRNO_123 (errno 123)



Cheers,
Dick Johnson

Penguin : Linux version 2.4.0 on an i686 machine (799.54 BogoMips).

"Memory is like gasoline. You use it up when you are running. Of
course you get it all back when you reboot..."; Actual explanation
obtained from the Micro$oft help desk.


2000-11-15 23:03:28

by Richard B. Johnson

[permalink] [raw]
Subject: Re: EJECT ioctl fails on empty SCSI CD-ROM

On Wed, 15 Nov 2000, Richard B. Johnson wrote:

> On Wed, 15 Nov 2000, James Stevenson wrote:
>
> >
> > Hi
> >
> > this is what i get on 2.2.17
> >
> > open("/dev/scd1", O_RDONLY|O_NONBLOCK) = 3
> > ioctl(3, CDROMEJECT, 0xbffffc78) = 0
> > close(3) = 0
> >
> >
> > >
> > >Is this the expected behavior? If so, I am curious to hear the rationale
> > >behind it.
> >
>
> Well the open fails with ENOMEDIUM (errno 123). This is hardly appropriate
> since you can't insert any "media" on some machines without a paperclip.
>
> readlink("/dev/cdrom", "", 256) = 9
> open("/dev/scd0", O_RDONLY) = -1 ERRNO_123 (errno 123)
>

Well, here is another 'eject'.


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

int main(int arg, char *argv[])
{
int fd;
if(((fd = open("/dev/cdrom", O_RDONLY|O_NONBLOCK)) > 0) ||
(arg > 1) && ((fd = open(argv[1], O_RDONLY|O_NONBLOCK)) > 0))
{
if(ioctl(fd, CDROMEJECT, NULL)) /* If it failed */
{
(void)ioctl(fd, CDROMRESET, NULL); /* Reset it */
(void)ioctl(fd, CDROMEJECT, NULL);
}
(void)close(fd);
exit(EXIT_SUCCESS);
}
perror("open");
exit(EXIT_FAILURE);
}


If there is no media in the drive, it fails to eject (open the tray).

open("/dev/cdrom", O_RDONLY|O_NONBLOCK) = 3
ioctl(3, CDROMEJECT, 0) = 671088642 -> error = 0
ioctl(3, 0x5312, 0) = 0 CDROMRESET
ioctl(3, CDROMEJECT, 0) = 671088642
close(3) = 0
_exit(0) = ?


I don't see an ioctl for CDROMOPENTRAY so I suppose CDROMEJECT
is the correct ioctl.

The last time I used CDROMEJECT, (Linux 2.2.17), it worked if there
was no media.

Cheers,
Dick Johnson

Penguin : Linux version 2.4.0 on an i686 machine (799.54 BogoMips).

"Memory is like gasoline. You use it up when you are running. Of
course you get it all back when you reboot..."; Actual explanation
obtained from the Micro$oft help desk.