openresolv-discuss

Hi Jeremy

On 16/11/2017 03:01, Jeremy Hansen wrote:
> I'm struggling with what I feel should be something really simple. I am 
> attempting to use resolvconf to update my resolv.conf when I connect to 
> a VPN using openvpn. I have installed your script on Slackware 14.2 
> using the SlackBuild 
> <https://slackbuilds.org/repository/14.2/network/openresolv/> available 
> on https://slackbuilds.org, passing the OPENVPN=yes option to it so it 
> will include a script (update-resolv-conf) to easily run your script 
> when the VPN connection status changes. That script seems to be 
> operating fine, but still wasn't updating my /etc/resolv.conf, so I 
> tried running the commands normally.
>
> I can get resolvconf to store the information for both devices (eth0 and 
> tun0) and can verify it using resolvconf -l, however, I can't get it to 
> update the /etc/resolv.conf. I feel like I'm missing something easy, but 
> I can't find it.
>
> I've tried variations of options, always including the -a tun0.inet, and 
> then trying the -u to force updating all "subscribers", as well as both 
> the -p and the -x options for private and exclusive. All seem to update 
> resolvconf's info, verified using resolvconf -l, but nothing seems to 
> update /etc/resolv.conf
>
> As can be seen from my output below, my eth0 device is getting its 
> address via dhcpcd.
>
> root@craven-moorhead:~# cat /etc/resolv.conf
> # Generated by dhcpcd from eth0.dhcp
> # /etc/resolv.conf.head can replace this line
> domain home
> nameserver 10.0.0.1
> # /etc/resolv.conf.tail can replace this line
> root@craven-moorhead:~# resolvconf -l
> # resolv.conf from eth0.dhcp
> # Generated by dhcpcd from eth0.dhcp
> domain home
> search home
> nameserver 10.0.0.1
>
> root@craven-moorhead:~# echo "nameserver 8.8.8.8" | resolvconf -u -a 
> tun0.inet
> root@craven-moorhead:~# resolvconf -l
> # resolv.conf from tun0.inet
> nameserver 8.8.8.8
>
> # resolv.conf from eth0.dhcp
> # Generated by dhcpcd from eth0.dhcp
> domain home
> search home
> nameserver 10.0.0.1
>
> root@craven-moorhead:~# cat /etc/resolv.conf
> # Generated by dhcpcd from eth0.dhcp
> # /etc/resolv.conf.head can replace this line
> domain home
> nameserver 10.0.0.1
> # /etc/resolv.conf.tail can replace this line
>
> I'd appreciate any help you can provide with this, and I'd be happy to 
> answer any questions you may have. Hopefully I'm just missing something 
> obvious.

OK this is identical from another user report that was sent to me 
privately. He was also a slackware user.

We discovered two problems:
1)  There were no subscriber scripts installed to the correct directory
2)  resolvconf is not in $PATH handed to dhcpcd

You can verify 1 by viewing the resovlconf file itself and look for 
LIBEXCECDIR at the top. Here's mine:
$grep LIBEXECDIR $(which resolvconf) | head -n 1
LIBEXECDIR=/libexec/resolvconf
$ ls -l /libexec/resolvconf
total 44
-r--r--r--  1 root  wheel  5681 Oct  4 01:35 dnsmasq
-r--r--r--  1 root  wheel  6812 Oct  4 01:35 libc
-r--r--r--  1 root  wheel  3646 Oct  4 01:35 named
-r--r--r--  1 root  wheel  2988 Oct  4 01:35 unbound

2, we didn't actually solve, but we can prove it because the dhcpcd hook 
script 20-resolv.conf will only write
# /etc/resolv.conf.head can replace this line
if it thinks resolvconf is not installed.
If you want to help debug it, you can create an /etc/dhcpcd.enter-hook 
like so

$ cat /etc/dhcpcd.enter-hook
( echo $PATH; type resolvconf) > /tmp/dhcpcd.resolv.log
$ cat /tmp/dhcpcd.resolv.log
/sbin:/bin:/usr/sbin:/usr/bin
resolvconf is /sbin/resolvconf

resolvconf is normally installed into /sbin, so it's always available, 
but it looks like slack installs it to /usr/sbin - is /usr on /, or is 
it a separate partition? If so, that is a potential issue.

Roy