# A hostname can either be a short hostname or a FQDN.
# hostname_fqdn=true
# hostname_fqdn=false
# hostname_fqdn=server
# A value of server means just what the server says, don't manipulate it.
# This could lead to an inconsistent hostname on a DHCPv4 and DHCPv6 network
# where the DHCPv4 hostname is short and the DHCPv6 has an FQDN.
# DHCPv6 has no hostname option.
# RFC4702 section 3.1 says FQDN should be prefered over hostname.
#
# As such, the default is hostname_fqdn=true so that a consistent hostname
# is always assigned.
: ${hostname_fqdn:=true}
# If we used to set the hostname, but relinquish control of it, we should
# reset to the default value.
: ${hostname_default=}
# Some systems don't have hostname(1)
_hostname()
{
if [ -z "${1+x}" ]; then
if [ -r /proc/sys/kernel/hostname ]; then
read name </proc/sys/kernel/hostname && echo "$name"
elif command -v hostname >/dev/null 2>/dev/null; then
hostname
elif sysctl kern.hostname >/dev/null 2>&1; then
sysctl -n kern.hostname
elif sysctl kernel.hostname >/dev/null 2>&1; then
sysctl -n kernel.hostname
else
return 1
fi
return $?
fi
if [ -w /proc/sys/kernel/hostname ]; then
echo "$1" >/proc/sys/kernel/hostname
elif [ -n "$1" ] && command -v hostname >/dev/null 2>&1; then
hostname "$1"
elif sysctl kern.hostname >/dev/null 2>&1; then
sysctl -w "kern.hostname=$1" >/dev/null
elif sysctl kernel.hostname >/dev/null 2>&1; then
sysctl -w "kernel.hostname=$1" >/dev/null
else
# May fail to set a blank hostname
hostname "$1"
fi
}
is_default_hostname()
{
case "$1" in
""|"$hostname_default"|localhost|localhost.localdomain)
return 0;;
esac
return 1
}
need_hostname()
{
# Always load the hostname variable for future use
hostname="$(_hostname)"
is_default_hostname "$hostname" && return 0
case "$force_hostname" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) return 0;;
esac
if [ -n "$old_fqdn" ]; then
if ${hfqdn} || ! ${hshort}; then
[ "$hostname" = "$old_fqdn" ]
else
[ "$hostname" = "${old_fqdn%%.*}" ]
fi
elif [ -n "$old_host_name" ]; then
if ${hfqdn}; then
if [ -n "$old_domain_name" ] &&
[ "$old_host_name" = "${old_host_name#*.}" ]
then
[ "$hostname" = \
"$old_host_name.$old_domain_name" ]
else
[ "$hostname" = "$old_host_name" ]
fi
elif ${hshort}; then
[ "$hostname" = "${old_host_name%%.*}" ]
else
[ "$hostname" = "$old_host_name" ]
fi
else
# No old hostname
false
fi
}
try_hostname()
{
[ "$hostname" = "$1" ] && return 0
if valid_domainname "$1"; then
syslog info "Setting hostname: $1"
_hostname "$1"
else
syslog err "Invalid hostname: $1"
fi
}
set_hostname()
{
hfqdn=false
hshort=false
case "$hostname_fqdn" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) hfqdn=true;;
""|[Ss][Ee][Rr][Vv][Ee][Rr]) ;;
*) hshort=true;;
esac
need_hostname || return 0
if [ -n "$new_fqdn" ]; then
if ${hfqdn} || ! ${hshort}; then
try_hostname "$new_fqdn"
else
try_hostname "${new_fqdn%%.*}"
fi
elif [ -n "$new_host_name" ]; then
if ${hfqdn}; then
if [ -n "$new_domain_name" ] &&
[ "$new_host_name" = "${new_host_name#*.}" ]
then
try_hostname "$new_host_name.$new_domain_name"
else
try_hostname "$new_host_name"
fi
elif ${hshort}; then
try_hostname "${new_host_name%%.*}"
else
try_hostname "$new_host_name"
fi
elif ! is_default_hostname "$hostname"; then
try_hostname "$hostname_default"
fi
}
# For ease of use, map DHCP6 names onto our DHCP4 names
case "$reason" in
BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6)
new_fqdn="$new_dhcp6_fqdn"
old_fqdn="$old_dhcp6_fqdn"
;;
esac
if $if_configured && $if_up && [ "$reason" != ROUTERADVERT ]; then
set_hostname
fi
