Re: group video?
On Sun, Aug 15, 1999 at 01:55:12PM -0600, Bdale Garbee wrote:
> Do we want/need a group 'video' to hold all the video4linux devices? In the
> same way that groups like audio, cdrom, dialout, etc are used to control
> permissions to a specific group of users, I'm thinking that making the video
> devices root/video/0660 would make things like xawtv easier to run.
>
> As the makedev maintainer, I'll be happy to update makedev if there is
> agreement.
>
> Bdale
Your posting made me wonder about the proper setup for the scsi generic
devices.
I have /dev/scd0 as a read-only CDROM, and /dev/scd1 as a cd writer.
freefall /dev $ ll scd{0,1}
brw-rw---- 1 root cdrom 11, 0 Mar 22 20:51 scd0
brw-rw---- 1 root cdrom 11, 1 Mar 22 20:51 scd1
To rip CD's, cdparanoia needs access to the scsi generic devices. I
tried permissions of:
freefall /dev $ ll sg*
crw-r----- 1 root cdrom 21, 0 Mar 22 20:51 sg0
crw-r----- 1 root cdrom 21, 1 Mar 22 20:51 sg1
crw-r----- 1 root cdrom 21, 10 Mar 22 20:51 sg10
crw-r----- 1 root cdrom 21, 11 Mar 22 20:51 sg11
crw-r----- 1 root cdrom 21, 12 Mar 22 20:51 sg12
crw-r----- 1 root cdrom 21, 13 Mar 22 20:51 sg13
crw-r----- 1 root cdrom 21, 14 Mar 22 20:51 sg14
crw-r----- 1 root cdrom 21, 15 Mar 22 20:51 sg15
crw-r----- 1 root cdrom 21, 16 Mar 22 20:51 sg16
crw-r----- 1 root cdrom 21, 2 Mar 22 20:51 sg2
crw-r----- 1 root cdrom 21, 3 Mar 22 20:51 sg3
crw-r----- 1 root cdrom 21, 4 Mar 22 20:51 sg4
crw-r----- 1 root cdrom 21, 5 Mar 22 20:51 sg5
crw-r----- 1 root cdrom 21, 6 Mar 22 20:51 sg6
crw-r----- 1 root cdrom 21, 7 Mar 22 20:51 sg7
crw-r----- 1 root cdrom 21, 8 Mar 22 20:51 sg8
crw-r----- 1 root cdrom 21, 9 Mar 22 20:51 sg9
But cdparanoia won't run as a normal user in group cdrom (it will run as
root):
/dev/cdrom exists but isn't accessible. By default,
cdparanoia stops searching for an accessible drive here.
Consider using -s to force a more complete autosense
of the machine.
More information about /dev/cdrom:
Checking /dev/cdrom for cdrom...
Testing /dev/cdrom for cooked ioctl() interface
/dev/scd0 is not a cooked ioctl CDROM.
Testing /dev/cdrom for SCSI interface
No generic SCSI device found to match CDROM device /dev/scd0
If I change the permissions on all the sg devices to group rw, I can
run cdparanoia as a normal user in group cdrom. But I don't want to
have all the scsi generic devices writeable by everyone in group cdrom.
And setting just the correct scsi devices to be writeable is dangerous,
because modifying the devices on the scsi bus may cause the generic
devices to point to different physical devices. That is, if I make the
scsi generic device for the cdrom writeable, it may be the scsi generic
device for a hard drive after some hardware modifications.
Does anyone see a problem with my /dev setup? Does cdparanoia really
need write permission to a cdrom drive in order to find it?
--
Lee Bradshaw lee@sectionIV.com (preferred)
Alantro Communications lee@alantro.com
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