devfs and bpf owner, group, and mode
freebsd-questions-local at be-well.ilk.org
Wed Nov 9 14:28:28 GMT 2005
David Kelly <dkelly at hiwaay.net> writes:
> I'm having problems in 5.4 getting automatic ownership and mode correct
> on /dev/bpf2. Added this to /etc/devfs.conf:
> # Allow group tcpdump to use bpf*
> own bpf0 root:tcpdump
> perm bpf0 0660
> own bpf1 root:tcpdump
> perm bpf1 0660
> own bpf2 root:tcpdump
> perm bpf2 0660
> And this to /etc/devfs.rules:
> add path 'bpf*' mode 0660 group tcpdump
> The intent is to allow members of group "tcpdump" to use /dev/bpf2
> without being root. The above creates /dev/bpf as desired at boot
> but some time later /dev/bpf2 disappears.
> System has two NICs, xl0 and fxp0. At this time fxp0 is not being used.
> Vlan0 is configured (as a VLAN of course) on xl0, and thats where I need
> /dev/bpf2 for tcpdump to see what my stuff is doing.
> If missing, /dev/bpf2 is created automatically when tcpdump opens, but
> its not created with the same ownership and mode as during reboot.
> Suspect my problem is related to [devfsrules_bpf=5] or the fact I
> haven't informed the system to apply this rule to the /dev filesystem.
Good guess. I'm still on my first cup of coffee, and might have taken
a few more minutes to spot that.
> So where is the 'i' that I've failed to dot?
try adding 'devfs_system_ruleset="devfsrules_bpf"' to rc.conf.
To apply it before reboot would be something roughly like
'devfs /dev ruleset devfsrules_bpf'.
Lowell Gilbert, embedded/networking software engineer, Boston area
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