procd, possible hotplug issue?

[Daniel Golle]

On Tue, Feb 20, 2024 at 11:47:49PM +0100, e9hack wrote:
> Am 20.02.2024 um 14:14 schrieb Paul D:
> > 
> > Could you show an example of this?
> > 
> 
> I modified /usr/lib/dnsmasq/dhcp-script.sh to see additional variables in the syslog:
> 
> --- dhcp-script.sh.orig 2024-02-14 16:22:53.000000000 +0100
> +++ dhcp-script.sh      2024-02-20 22:55:33.000000000 +0100
> @@ -50,4 +50,7 @@ esac
> 
>  json_close_array env
> 
> -[ -n "$hotplugobj" ] && ubus call hotplug.${hotplugobj} call "$(json_dump)"
> +[ -n "$hotplugobj" ] && {
> +       logger -t dhcp-script "ubus call hotplug.${hotplugobj} call \"$(json_dump)\""
> +       ubus call hotplug.${hotplugobj} call "$(json_dump)"
> +}
> 
> 
> 'logread -e 192.168.104.82' with HOSTNAME empty shows:
> Tue Feb 20 23:14:33 2024 user.notice dhcp-script: ubus call hotplug.dhcp call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=update", "HOSTNAME=" ] }"
> Tue Feb 20 23:14:33 2024 user.notice dhcp-script: ubus call hotplug.dhcp call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=update", "HOSTNAME=" ] }"
> Tue Feb 20 23:14:34 2024 user.notice nft-qos-monitor: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, HOSTNAME=WLAN-DSL9
> Tue Feb 20 23:14:34 2024 user.notice dhcp-script: ubus call hotplug.neigh call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=add" ] }"
> Tue Feb 20 23:14:34 2024 user.notice nft-qos-dynamic: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, HOSTNAME=WLAN-DSL9
> Tue Feb 20 23:14:35 2024 user.notice dhcp-script: ubus call hotplug.neigh call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=add" ] }"
> Tue Feb 20 23:14:35 2024 user.notice nft-qos-monitor: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, HOSTNAME=WLAN-DSL9
> Tue Feb 20 23:14:36 2024 user.notice nft-qos-dynamic: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, HOSTNAME=WLAN-DSL9
> 
> 'logread -e 192.168.104.84' with HOSTNAME set shows:
> Tue Feb 20 23:14:34 2024 user.notice dhcp-script: ubus call hotplug.dhcp call "{ "env": [ "MACADDR=bb:bb:bb:bb:bb:bb", "IPADDR=192.168.104.84", "ACTION=update", "HOSTNAME=raspberrypi2" ] }"
> Tue Feb 20 23:14:34 2024 user.notice dhcp-script: ubus call hotplug.neigh call "{ "env": [ "MACADDR=bb:bb:bb:bb:bb:bb", "IPADDR=192.168.104.84", "ACTION=add" ] }"
> Tue Feb 20 23:14:35 2024 user.notice dhcp-script: ubus call hotplug.neigh call "{ "env": [ "MACADDR=bb:bb:bb:bb:bb:bb", "IPADDR=192.168.104.84", "ACTION=add" ] }"
> Tue Feb 20 23:14:36 2024 user.notice nft-qos-monitor: ACTION=update, MACADDR=bb:bb:bb:bb:bb:bb, IPADDR=192.168.104.84, HOSTNAME=raspberrypi2
> Tue Feb 20 23:14:36 2024 user.notice nft-qos-dynamic: ACTION=update, MACADDR=bb:bb:bb:bb:bb:bb, IPADDR=192.168.104.84, HOSTNAME=raspberrypi2
> 
> WLAN-DSL9 is the router name:
> root at WLAN-DSL9:~# echo $HOSTNAME
> WLAN-DSL9
> 
> If I replace HOSTNAME by DHCP_HOSTNAME in /usr/lib/dnsmasq/dhcp-script.sh, /etc/hotplug.d/dhcp/00-nft-qos-monitor and /etc/hotplug.d/dhcp/01-nft-qos-dynamic, I get the following output:
> 
> Tue Feb 20 23:44:43 2024 user.notice dhcp-script: ubus call hotplug.dhcp call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=update", "DHCP_HOSTNAME=" ] }"
> Tue Feb 20 23:44:43 2024 user.notice dhcp-script: ubus call hotplug.dhcp call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=update", "DHCP_HOSTNAME=" ] }"
> Tue Feb 20 23:44:44 2024 user.notice nft-qos-monitor: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, DHCP_HOSTNAME=
> Tue Feb 20 23:44:44 2024 user.notice dhcp-script: ubus call hotplug.neigh call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=add" ] }"
> Tue Feb 20 23:44:44 2024 user.notice nft-qos-dynamic: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, DHCP_HOSTNAME=
> Tue Feb 20 23:44:45 2024 user.notice dhcp-script: ubus call hotplug.neigh call "{ "env": [ "MACADDR=aa:aa:aa:aa:aa:aa", "IPADDR=192.168.104.82", "ACTION=add" ] }"
> Tue Feb 20 23:44:45 2024 user.notice nft-qos-monitor: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, DHCP_HOSTNAME=
> Tue Feb 20 23:44:46 2024 user.notice nft-qos-dynamic: ACTION=update, MACADDR=aa:aa:aa:aa:aa:aa, IPADDR=192.168.104.82, DHCP_HOSTNAME=
> 
> If procd generates the hotplug call, it filters out empty variables. From procd hotplug-dispatch.c line 239:
> 
> 		*tmp = '\0';
> 		if (validate_envvarname(enve))
> 			continue;
> 		*tmp = '=';
> 
> 		if (!strlen(++tmp))
> 			continue;

Yep, I didn't think about empty variables when I built this...

Can you test this please:
https://github.com/openwrt/procd/pull/3


> 
> Regards,
> Hartmut
> 
> 
> 
> 
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