/etc/dhcpcd.sh is in dhcpcd 1:3.2.3-9ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 | #!/bin/bash
#
# This is a sample /etc/dhcpc/dhcpcd.sh script.
# /etc/dhcpc/dhcpcd.sh script is executed by dhcpcd daemon
# any time it configures or shuts down interface.
# The following parameters are passed to dhcpcd.sh script:
# $1 = HostInfoFilePath, e.g "/var/lib/dhcpc/dhcpcd-eth0.info"
# $2 = "up" if interface has been configured with the same
# IP address as before reboot;
# $2 = "down" if interface has been shut down;
# $2 = "new" if interface has been configured with new IP address;
#
# This script sources /var/lib/dhcpc/dhcpcd-<interface>.info which defines
# a set of variables.
# NOTE THAT THE DATA IN SOME OF THESE VARIABLES COME FROM
# UNTRUSTED SOURCES AND ARE UNCHECKED.
# The variables in question are HOSTNAME, DOMAIN, NISDOMAIN,
# ROOTPATH DNSSEARCH and DHCPSNAME. Enough quoting is done to ensure that
# execution of this script is safe, but beware if you pass the value of any of
# these variables to another shell or perl script - there is nothing to
# stop an attacker putting dangerous characters in these variables.
#
# This is important: if noglob not set a filename expansion metachar may be
# included in one of the variables set in the info file and executed
# if that variable is used.
# Try this to see the effect:
# TEST='*'; echo $TEST
set -o noglob
# Sanity checks
if [ $# -lt 2 ]; then
logger -s -p local0.err -t dhcpcd.sh "wrong usage"
exit 1
fi
hostinfo="$1"
state="$2"
# Reading HostInfo file for configuration parameters
if ! [ -f ${hostinfo} ]; then
logger -s -p local0.err -t dhcpcd.sh "No hostinfo file"
exit 1
fi
. ${hostinfo}
write_resolv_info()
{
dnsservs=${DNSSERVERS}
r=""
[ "$dnsservs" != "" ] && [ "$DNSSEARCH" != "" ] && r="${r}search $DNSSEARCH
"
[ "$dnsservs" != "" ] && [ "$DNSSEARCH" == "" ] && [ "$DNSDOMAIN" != "" ] && r="${r}search $DNSDOMAIN
"
for serv in $dnsservs; do
r="${r}nameserver $serv
"
done
if [ -x /sbin/resolvconf ] ; then
echo -n "$r" | /sbin/resolvconf -a "$INTERFACE"
else
# set /etc/dhcpc/resolv.conf for compatiblity with older packages
echo -n "$r" >| /etc/dhcpc/resolv.conf
chmod 644 /etc/dhcpc/resolv.conf
fi
}
delete_resolv_info()
{
if [ -x /sbin/resolvconf ] ; then
/sbin/resolvconf -d "$INTERFACE"
fi
}
case ${state} in
up) logger -s -p local0.info -t dhcpcd.sh "interface ${INTERFACE} has been configured with old IP=${IPADDR}"
write_resolv_info
# ==== Put your code for the case interface has been brought up with old IP address here
# ==== End
;;
new) logger -s -p local0.info -t dhcpcd.sh "interface ${INTERFACE} has been configured with new IP=${IPADDR}"
write_resolv_info
# ==== Put your code for the case interface has been brought up with new IP address here
# ==== End
;;
down) logger -s -p local0.info -t dhcpcd.sh "interface ${INTERFACE} has been brought down"
delete_resolv_info
# ==== Put your code for the case interface has been shut down here
# ==== End
;;
esac
exit 0
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