Subject: Re: [linux-audio-user] audio cdrom permissions
From: derek holzer (derek_AT_x-i.net)
Date: Mon May 19 2003 - 23:56:41 EEST
hi gang,
still tracking this problem, so let me reply to the two kind people that
have written so far. to clarify, i am trying to RIP audio, not BURN it.
it seems both folks started thinking about write permissions and not
necessarily read permissions.
devdsp_AT_mail2.inform.dk wrote:
>>The easiest way is to chmod all of these entries to 777. You need to be able to
>>write to your CD-ROM drive as a regular user, after all :)
>>
>>
i have done this, and it makes no difference. also, being a member of
group "cdrom" and "disk" doesn't make much diff, so i can't imagine that
being in "cdromwriter", as you suggest elsewhere, would change this.....
funny thing is that it ACTS like i haven't changed these permissions! as
you can see below, when i try chmod 777, it doesn't affect it, even
though i am 'su'... what am i doing wrong here?
debian:/home/derek# chmod 777 /dev/sg0
debian:/home/derek# ls -al /dev/sg0
lr-xr-xr-x 1 root root 36 May 19 22:15 /dev/sg0 ->
scsi/host0/bus0/target0/lun0/generic
Paul Perkins wrote:
>Under 2.4.x kernel (or earlier), burning CDs (and possibly ripping audio
>CDs too) needs access to the "generic scsi" device for the drive (don't
>you love those violent terms for copying data?). Conventionally called
>/dev/sg0, device (21,0). The "0" may be another number if you have
>multiple real or emulated SCSI devices. I'm not sure, but I think this
>may change in the 2.6 kernel series.
>
i do have a /dev/sr0
lr-xr-xr-x 1 root root 36 May 19 22:15 /dev/sg0 ->
scsi/host0/bus0/target0/lun0/generic
and the new permissions for its target are as follows:
debian:/# ls -al /dev/scsi/host1/bus0/target0/lun0/
total 0
drwxrwxrwx 1 root root 0 Jan 1 1970 .
drwxr-xr-x 1 root root 0 Jan 1 1970 ..
brwxrwxrwx 1 root cdrom 11, 0 Jan 1 1970 cd
crwxrwxrwx 1 root root 21, 1 Jan 1 1970 generic
once i changed the permissions sucessfully to those above, cdparanoia
gives me this when i try to Query an audio CD:
--------------begin
debian:/home/derek# cdparanoia -vQ
cdparanoia III release 9.8 (March 23, 2001)
(C) 2001 Monty <monty_AT_xiph.org> and Xiphophorus
Report bugs to paranoia_AT_xiph.org
http://www.xiph.org/paranoia/
Checking /dev/cdrom for cdrom...
Testing /dev/cdrom for cooked ioctl() interface
/dev/scsi/host1/bus0/target0/lun0/cd is not a cooked ioctl CDROM.
Testing /dev/cdrom for SCSI interface
generic device: /dev/scsi/host1/bus0/target0/lun0/generic
ioctl device: /dev/scsi/host1/bus0/target0/lun0/cd
Found an accessible SCSI CDROM drive.
Looking at revision of the SG interface in use...
SG interface version 3.1.24; OK.
CDROM model sensed sensed: TOSHIBA DVD-ROM SD-C2502 1711
Checking for SCSI emulation...
Drive is ATAPI (using SCSI host adaptor emulation)
Checking for MMC style command set...
Drive is MMC style
004: Unable to read table of contents header
Unable to open disc. Is there an audio CD in the drive?
-----------------end
so i am still not sure what the problem is....
>If some of the applications you are using are installed with set-uid,
>(perhaps on a helper program rather than the main one), that would
>explain why similar actions may only work as user root in one
>application, but work as a normal user in another application.
>
none of the apps were knowingly installed set-uid... they all came from
deb packages, though, so i know of no way to tell for certain. how to
find out? how to change?
it's stuff like this that makes me think my laptop is haunted ;-)
thanks for your suggestions,
derek
>On Sun, 2003-05-18 at 13:03, derek holzer wrote:
>
>
>>> i've been having a bit of trouble with playing and ripping CDs, maybe
>>> someone here can help?
>>>
>>> i'm running Debian on a laptop, and as root i don't have any serious
>>> problems doing either, but as a user it becomes a bit wierd... let me
>>> explain...
>>>
>>> as user, i am in groups cdrom and disk. i have set permissions as follows:
>>>
>>> in /dev:
>>> lr-xr-xr-x 1 root root 13 May 18 17:31 cdrom ->
>>> cdroms/cdrom0
>>> drwxr-xr-x 1 root root 0 Jan 1 1970 cdroms
>>>
>>> in /dev/cdroms
>>> lr-xr-xr-x 1 root root 34 Jan 1 1970 cdrom0 ->
>>> ../scsi/host1/bus0/target0/lun0/cd
>>>
>>> in /dev/scsi/host1/bus0/target0/lun0/
>>> brw-rw-rw- 1 root cdrom 11, 0 Jan 1 1970 cd
>>>
>>> i have none of these other cdrom devices listed in /dev:
>>> /dev/hdc
>>> /dev/sr0
>>> /dec/scd0
>>> but my drive appears to be ATAPI with SCSI emulation. i have added the
>>> following to my /etc/lilo.conf to reflect this:
>>> append="hdc=ide-scsi"
>>> although commenting this out doesn't seem to do much.
>>>
>>> i can rip CDs as a user with Grip, but RipperX tells me i need
>>> permission to access the CD drive [cannot open cdrom drive]. i can play
>>> CD audio with Alsaplayer, but not with XMMS. likewise, xfreecd doesn't
>>> find the drive, but workman does. very inconsistant! running cdparanoia
>>> -vQ as user gives the following:
>>>
>>> Checking /dev/cdrom for cdrom...
>>> Testing /dev/cdrom for cooked ioctl() interface
>>> /dev/scsi/host1/bus0/target0/lun0/cd is not a cooked ioctl CDROM.
>>> Testing /dev/cdrom for SCSI interface
>>> No generic SCSI device found to match CDROM device
>>> /dev/scsi/host1/bus0/target0/lun0/cd
>>>
>>> it seems that there are still some permissions to change somewhere, but
>>> i can't for the life of me figure out where!
>>>
>>> what have i missed?
>>>
>>> thanks,
>>> derek
>>
>>
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