1# Set the hostname from DHCP data if required 2 3# A hostname can either be a short hostname or a FQDN. 4# hostname_fqdn=true 5# hostname_fqdn=false 6# hostname_fqdn=server 7 8# A value of server means just what the server says, don't manipulate it. 9# This could lead to an inconsistent hostname on a DHCPv4 and DHCPv6 network 10# where the DHCPv4 hostname is short and the DHCPv6 has an FQDN. 11# DHCPv6 has no hostname option. 12# RFC4702 section 3.1 says FQDN should be prefered over hostname. 13# 14# As such, the default is hostname_fqdn=true so that a consistent hostname 15# is always assigned. 16: ${hostname_fqdn:=true} 17 18# If we used to set the hostname, but relinquish control of it, we should 19# reset to the default value. 20: ${hostname_default=} 21 22# Some systems don't have hostname(1) 23_hostname() 24{ 25 if [ -z "${1+x}" ]; then 26 if [ -r /proc/sys/kernel/hostname ]; then 27 read name </proc/sys/kernel/hostname && echo "$name" 28 elif command -v hostname >/dev/null 2>/dev/null; then 29 hostname 30 elif sysctl kern.hostname >/dev/null 2>&1; then 31 sysctl -n kern.hostname 32 elif sysctl kernel.hostname >/dev/null 2>&1; then 33 sysctl -n kernel.hostname 34 else 35 return 1 36 fi 37 return $? 38 fi 39 40 if [ -w /proc/sys/kernel/hostname ]; then 41 echo "$1" >/proc/sys/kernel/hostname 42 elif [ -n "$1" ] && command -v hostname >/dev/null 2>&1; then 43 hostname "$1" 44 elif sysctl kern.hostname >/dev/null 2>&1; then 45 sysctl -w "kern.hostname=$1" >/dev/null 46 elif sysctl kernel.hostname >/dev/null 2>&1; then 47 sysctl -w "kernel.hostname=$1" >/dev/null 48 else 49 # May fail to set a blank hostname 50 hostname "$1" 51 fi 52} 53 54is_default_hostname() 55{ 56 case "$1" in 57 ""|"$hostname_default"|localhost|localhost.localdomain) 58 return 0;; 59 esac 60 return 1 61} 62 63need_hostname() 64{ 65 # Always load the hostname variable for future use 66 hostname="$(_hostname)" 67 is_default_hostname "$hostname" && return 0 68 69 case "$force_hostname" in 70 [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) return 0;; 71 esac 72 73 if [ -n "$old_fqdn" ]; then 74 if ${hfqdn} || ! ${hshort}; then 75 [ "$hostname" = "$old_fqdn" ] 76 else 77 [ "$hostname" = "${old_fqdn%%.*}" ] 78 fi 79 elif [ -n "$old_host_name" ]; then 80 if ${hfqdn}; then 81 if [ -n "$old_domain_name" ] && 82 [ "$old_host_name" = "${old_host_name#*.}" ] 83 then 84 [ "$hostname" = \ 85 "$old_host_name.$old_domain_name" ] 86 else 87 [ "$hostname" = "$old_host_name" ] 88 fi 89 elif ${hshort}; then 90 [ "$hostname" = "${old_host_name%%.*}" ] 91 else 92 [ "$hostname" = "$old_host_name" ] 93 fi 94 else 95 # No old hostname 96 false 97 fi 98} 99 100try_hostname() 101{ 102 [ "$hostname" = "$1" ] && return 0 103 if valid_domainname "$1"; then 104 syslog info "Setting hostname: $1" 105 _hostname "$1" 106 else 107 syslog err "Invalid hostname: $1" 108 fi 109} 110 111set_hostname() 112{ 113 hfqdn=false 114 hshort=false 115 case "$hostname_fqdn" in 116 [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) hfqdn=true;; 117 ""|[Ss][Ee][Rr][Vv][Ee][Rr]) ;; 118 *) hshort=true;; 119 esac 120 121 need_hostname || return 122 123 if [ -n "$new_fqdn" ]; then 124 if ${hfqdn} || ! ${hshort}; then 125 try_hostname "$new_fqdn" 126 else 127 try_hostname "${new_fqdn%%.*}" 128 fi 129 elif [ -n "$new_host_name" ]; then 130 if ${hfqdn}; then 131 if [ -n "$new_domain_name" ] && 132 [ "$new_host_name" = "${new_host_name#*.}" ] 133 then 134 try_hostname "$new_host_name.$new_domain_name" 135 else 136 try_hostname "$new_host_name" 137 fi 138 elif ${hshort}; then 139 try_hostname "${new_host_name%%.*}" 140 else 141 try_hostname "$new_host_name" 142 fi 143 elif ! is_default_hostname "$hostname"; then 144 try_hostname "$hostname_default" 145 fi 146} 147 148# For ease of use, map DHCP6 names onto our DHCP4 names 149case "$reason" in 150BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6) 151 new_fqdn="$new_dhcp6_fqdn" 152 old_fqdn="$old_dhcp6_fqdn" 153 ;; 154esac 155 156if $if_configured && $if_up && [ "$reason" != ROUTERADVERT ]; then 157 set_hostname 158fi 159