Re: cdrecord suddenly doesn't allow burning

[Andreas Janssen <andreas.janssen@bigfoot.com>]

Hello

Joris Huizer (<joris_huizer@yahoo.com>) wrote:

> Well that idea about cdrecord seems to be the case
> indeed. However, I did
> chown root:cdrom cdrecord.mmap
> chown root:cdrom cdrecord.shm
> 
> And ls -l /usr/bin/cdrecord* now gives me:
> -rws--x---    1 root     cdrom         142 Jul 10
> 14:16 /usr/bin/cdrecord
> -rwxr-xr-x    1 root     cdrom        307K Jul 10
> 14:16 /usr/bin/cdrecord.mmap
> -rwxr-xr-x    1 root     cdrom        307K Jul 10
> 14:16 /usr/bin/cdrecord.shm


> I was allready in the cdrom group so I tried the
> following. I did chmod +r /usr/bin/cdrecord - and now
> running cdrecord results in:
> 
> jorishuizer@debian:~$ cdrecord -v -eject -force -immed
> speed=1 dev=0,0,0 cd_image
> Cdrecord 2.01a16 (i686-pc-linux-gnu) Copyright (C)
> 1995-2003 Jörg Schilling
> TOC Type: 1 = CD-ROM
> cdrecord.mmap: Operation not permitted. WARNING:
> Cannot do mlockall(2).
> cdrecord.mmap: WARNING: This causes a high risk for
> buffer underruns.
> cdrecord.mmap: Operation not permitted. WARNING:
> Cannot set RR-scheduler
> cdrecord.mmap: Permission denied. WARNING: Cannot set
> priority using setpriority().
> cdrecord.mmap: WARNING: This causes a high risk for
> buffer underruns.
> scsidev: '0,0,0'
> scsibus: 0 target: 0 lun: 0
> cdrecord.mmap: Permission denied. Cannot open
> '/dev/sg0'. Cannot open SCSI driver.
> cdrecord.mmap: For possible targets try 'cdrecord
> -scanbus'. Make sure you are root.
> cdrecord.mmap: For possible transport specifiers try
> 'cdrecord dev=help'.
> cdrecord.mmap: Also make sure that you have loaded the
> sg driver and the driver for
> cdrecord.mmap: SCSI hardware, eg. ide-scsi if you run
> IDE/ATAPI drives over
> cdrecord.mmap: ide-scsi emulation. Read
> /usr/share/doc/cdrecord/README.ATAPI.setup!
> 
> ?? now what should I do ? Should I change /dev/sg0 to
> the cdrom group too ? :-s

Yes, you should change that Set them to cdrom group and make them
read-writable for the group.

BTW, please correct me if I am wrong, but I think if you want to run
cdrecord suid root, setting the suid bit on the /usr/bin/cdrecord
script will not work (as suid bits on scripts are ignored). Instead,
you will have to set the suid bit on the binaries. 

best regards
        Andreas Janssen

-- 
Andreas Janssen
andreas.janssen@bigfoot.com
PGP-Key-ID: 0xDC801674
Registered Linux User #267976