#!/usr/bin/sh
# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
# ex: ts=8 sw=4 sts=4 et filetype=sh
#
PATH=/usr/sbin:/usr/bin:/sbin:/bin
# File to start dhclient requests on different interfaces in parallel
. /lib/dracut-lib.sh
. /lib/net-lib.sh
netif=$1
do_vlan=$2
arg=$3
# Run dhclient in parallel
do_dhclient() {
local _COUNT=0
local _timeout
local _DHCPRETRY
_timeout=$(getarg rd.net.timeout.dhcp=)
_DHCPRETRY=$(getargnum 1 1 1000000000 rd.net.dhcp.retry=)
while [ $_COUNT -lt "$_DHCPRETRY" ]; do
info "Starting dhcp for interface $netif"
dhclient "$arg" \
${_timeout:+--timeout "$_timeout"} \
-q \
-1 \
-cf /etc/dhclient.conf \
-pf /tmp/dhclient."$netif".pid \
-lf /tmp/dhclient."$netif".lease \
"$netif" &
wait $! 2> /dev/null
# wait will return the return value of dhclient
retv=$?
# dhclient and hence wait returned success, 0.
if [ $retv -eq 0 ]; then
return 0
fi
# If dhclient exited before wait was called, or it was killed by
# another thread for interface whose DHCP succeeded, then it will not
# find the process with that pid and return error code 127. In that
# case we need to check if /tmp/dhclient.$netif.lease exists. If it
# does, it means dhclient finished executing before wait was called,
# and it was successful (return 0). If /tmp/dhclient.$netif.lease
# does not exist, then it means dhclient was killed by another thread
# or it finished execution but failed dhcp on that interface.
if [ $retv -eq 127 ]; then
pid=$(cat /tmp/dhclient."$netif".pid)
info "PID $pid was not found by wait for $netif"
if [ -e /tmp/dhclient."$netif".lease ]; then
info "PID $pid not found but DHCP successful on $netif"
return 0
fi
fi
_COUNT=$((_COUNT + 1))
[ $_COUNT -lt "$_DHCPRETRY" ] && sleep 1
done
warn "dhcp for interface $netif failed"
# nuke those files since we failed; we might retry dhcp again if it's e.g.
# `ip=dhcp,dhcp6` and we check for the PID file earlier
rm -f /tmp/dhclient."$netif".pid /tmp/dhclient."$netif".lease
return 1
}
do_dhclient
ret=$?
# setup nameserver
for s in "$dns1" "$dns2" $(getargs nameserver); do
[ -n "$s" ] || continue
echo nameserver "$s" >> /tmp/net."$netif".resolv.conf
done
if [ $ret -eq 0 ]; then
: > /tmp/net."${netif}".up
if [ -z "$do_vlan" ] && [ -e /sys/class/net/"${netif}"/address ]; then
: > "/tmp/net.$(cat /sys/class/net/"${netif}"/address).up"
fi
# Check if DHCP also suceeded on another interface before this one.
# We will always use the first one on which DHCP succeeded, by using
# a commom file $IFNETFILE, to synchronize between threads.
# Consider the race condition in which multiple threads
# corresponding to different interfaces may try to read $IFNETFILE
# and find it does not exist; they may all end up thinking they are the
# first to succeed (hence more than one thread may end up writing to
# $IFNETFILE). To take care of this, instead of checking if $IFNETFILE
# exists to determine if we are the first, we create a symbolic link
# in $IFNETFILE, pointing to the interface name ($netif), thus storing
# the interface name in the link pointer.
# Creating a link will fail, if the link already exists, hence kernel
# will take care of allowing only first thread to create link, which
# takes care of the race condition for us. Subsequent threads will fail.
# Also, the link points to the interface name, which will tell us which
# interface succeeded.
if ln -s "$netif" "$IFNETFILE" 2> /dev/null; then
intf=$(readlink "$IFNETFILE")
if [ -e /tmp/dhclient."$intf".lease ]; then
info "DHCP successful on interface $intf"
# Kill all existing dhclient calls for other interfaces, since we
# already got one successful interface
npid=$(cat /tmp/dhclient."$netif".pid)
pidlist=$(pgrep dhclient)
for pid in $pidlist; do
[ "$pid" -eq "$npid" ] && continue
kill -9 "$pid" > /dev/null 2>&1
done
else
echo "ERROR! $IFNETFILE exists but /tmp/dhclient.$intf.lease does not exist!!!"
fi
else
info "DHCP success on $netif, and also on $intf"
exit 0
fi
exit $ret
fi
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