Subject: Re: [linux-audio-user] audio cdrom permissions
From: Paul Perkins (speaker-to-vegetables_AT_pobox.com)
Date: Wed May 21 2003 - 14:59:41 EEST
I don't see any more permissions problems here. I have seen a particular
drive/motherboard combo where reading the Table of Contents (TOC) of an
audio CD would not work. I swapped drives (different brands of el cheapo
CDRW) between two machines, after which both systems could read & rip
audio! You might have a similar situation, not a software configuration
problem but an incompatibility among the drive, the motherboard, and the
device driver software. There could be a work-around, but I have no idea
what it would be. For what it's worth, the machine where the problem
showed up identifies its IDE interface (via lspci -v) as a "VIA
Technologies, Inc. VT82C586B".
Good luck.
Paul
On Mon, 2003-05-19 at 16:56, derek holzer wrote:
> 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
> >>
> >>
>
>
-- sigmotto: Liberty is theft.
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