|DHCPCD-RUN-HOOKS(8)||System Manager's Manual||DHCPCD-RUN-HOOKS(8)|
dhcpcd-run-hooksis used by dhcpcd(8) to run any system and user defined hook scripts. System hook scripts are found in /usr/lib/dhcpcd/dhcpcd-hooks and the user defined hooks are /etc/dhcpcd.enter-hook. and /etc/dhcpcd.exit-hook. The default install supplies hook scripts for configuring /etc/resolv.conf and the hostname. Your distribution may have included other hook scripts to say configure ntp or ypbind. A test hook is also supplied that simply echos the dhcp variables to the console from DISCOVER message.
The hooks scripts are loaded into the current shell rather than
executed in their own process. This allows each hook script, such as
/etc/dhcpcd.enter-hook to customise environment
variables or provide alternative functions to hooks further down the chain.
As such, using the shell builtins
exec or similar will cause
dhcpcd-run-hooks to exit at that point.
dhcpcd-run-hooks is invoked,
$interface is set to the interface that
dhcpcd is run on and
is to the reason why
dhcpcd-run-hooks was invoked.
DHCP information to be configured is held in variables starting with the
word new_ and old DHCP information to be removed is held in variables
starting with the word old_.
dhcpcd can display the
full list of variables it knows how about by using the
Here's a list of reasons why
dhcpcd-run-hooks could be invoked:
- dhcpcd is starting up and any pre-initialisation should be done.
- dhcpcd has detected the carrier is up. This is generally just a notification and no action need be taken.
- dhcpcd lost the carrier. The cable may have been unplugged or association to the wireless point lost.
- dhcpcd informed a DHCP server about it's address and obtained other configuration details.
- dhcpcd obtained a new lease from a DHCP server.
- dhcpcd renewed it's lease.
- dhcpcd has rebound to a new DHCP server.
- dhcpcd successfully requested a lease from a DHCP server.
- dhcpcd assigned a delegated prefix to the interface.
- dhcpcd obtained an IPV4LL address, or one was removed.
- dhcpcd has been configured with a static configuration which has not been obtained from a DHCP server.
- dhcpcd is monitoring the interface for a 3rd party to give it an IP address.
- dhcpcd failed to contact any DHCP servers but was able to use an old lease.
- dhcpcd's lease or state expired and it failed to obtain a new one.
- dhcpcd received a NAK from the DHCP server. This should be treated as EXPIRE.
- dhcpcd has been instructed to reconfigure an interface.
- dhcpcd has received an IPv6 Router Advertisement, or one has expired.
- dhcpcd stopped running on the interface.
- dhcpcd has stopped entirely.
- The interface has been removed.
- dhcpcd failed to operate on the interface. This normally happens when dhcpcd does not support the raw interface, which means it cannot work as a DHCP or ZeroConf client. Static configuration and DHCP INFORM is still allowed.
- dhcpcd has been asked to dump the last lease for the interface.
- dhcpcd received an OFFER from a DHCP server but will not configure the interface. This is primarily used to test the variables are filled correctly for the script to process them.
dhcpcdwill clear the environment variables aside from
$RC_SVCNAME. The following variables will then be set, along with any protocol supplied ones.
- the name of the interface.
- the protocol that triggered the event.
- as described above.
- the pid of
- the link status of
$interfacepreference, lower is better.
$interfaceis wireless, otherwise
- the name of the SSID the
interfaceis connected to.
- A list of interfaces, in order of preference.
interfaceis up, otherwise
interfaceis down, otherwise
- Address family waiting for, as defined in dhcpcd.conf(5).
- the name of the profile selected from dhcpcd.conf(5).
- space separated list of delegated prefixes.
dhcpcd-run-hooksruns, it loads /etc/dhcpcd.enter-hook and any scripts found in /usr/lib/dhcpcd/dhcpcd-hooks in a lexical order and then finally /etc/dhcpcd.exit-hook
dhcpcdwill validate the content of each option against its encoding. For string, ascii, raw or binhex encoding it's up to the user to validate it for the intended purpose.
When used in a shell script, each variable must be quoted correctly.
|February 20, 2018||Linux 5.4.2-arch1-1|