[__hostame] Simplify and revert hostnamectl to be a last resort

cdist/conf/type/__hostname/explorer/persistent_hostname

@@ -1,66 +0,0 @@
-#!/bin/sh
-#
-# 2019 Dennis Camera (dennis.camera at ssrq-sds-fds.ch)
-#
-# This file is part of cdist.
-#
-# cdist is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# cdist is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with cdist. If not, see <http://www.gnu.org/licenses/>.
-#
-#
-# Retrieve the persistent hostname
-#
-
-# Firstly, check hostnamectl if available.
-if command -v hostnamectl >/dev/null 2>&1
-then
-	hostnamectl status --static && exit 0
-fi
-
-# In case hostnamectl is missing or failed:
-# Fall back to alternative OS-specific approaches.
-case $("$__explorer/os")
-in
-	alpine|archlinux|coreos|debian|devuan|ubuntu)
-		test -f /etc/hostname && cat /etc/hostname
-		;;
-	centos|fedora|redhat|scientific)
-		test -f /etc/sysconfig/network \
-			&& (. /etc/sysconfig/network && echo "$HOSTNAME")
-		;;
-	freebsd)
-		(. /etc/rc.conf && echo "$hostname")
-		;;
-	gentoo)
-		(. /etc/conf.d/hostname && echo "$hostname")
-		;;
-	macosx)
-		scutil --get HostName 2>/dev/null
-		;;
-	netbsd)
-		if grep -q '^hostname=' /etc/rc.conf
-		then
-			(. /etc/rc.conf && echo "$hostname")
-		elif [ -f /etc/myname ]
-		then
-			# Fall back to /etc/myname file
-			cat /etc/myname
-		fi
-		;;
-	openbsd)
-		cat /etc/myname
-		;;
-	suse)
-		cat /etc/HOSTNAME 2>/dev/null
-		;;
-esac

cdist/conf/type/__hostname/gencode-remote

@@ -22,17 +22,17 @@
 
 os=$(cat "$__global/explorer/os")
 name_running=$(cat "$__global/explorer/hostname")
-name_config=$(cat "$__object/explorer/persistent_hostname")
 has_hostnamectl=$(cat "$__object/explorer/has_hostnamectl")
 
 
-if [ -f "$__object/parameter/name" ]; then
+if test -s "$__object/parameter/name"
-    name_should="$(cat "$__object/parameter/name")"
+then
+    name_should=$(cat "$__object/parameter/name")
 else
     case $os
     in
         # RedHat-derivatives and BSDs
-        centos|fedora|redhat|scientific|freebsd|netbsd|openbsd)
+        centos|fedora|redhat|scientific|freebsd|macosx|netbsd|openbsd)
             # Hostname is FQDN
             name_should="${__target_host}"
         ;;
@@ -43,66 +43,49 @@ else
     esac
 fi
 
+
 ################################################################################
-# Check if the hostname is already correct
+# Check if the (running) hostname is already correct
 #
-if [ "$name_running" = "$name_should" ] \
+test "$name_running" != "$name_should" || exit 0
-  && [ -z "$name_config" -o "$name_config" = "$name_should" ]
+
-then
-    exit 0
-fi
 
 ################################################################################
 # Setup hostname
 #
 echo 'changed' >>"$__messages_out"
 
-
+# Use the good old way to set the hostname.
-# First try to set the hostname using hostnamectl, if available.
-if [ -n "$has_hostnamectl" ]; then
-    # Allow hostnamectl to fail silently.
-    # Who the fuck invented a tool that needs dbus to set the hostname anyway…
-
-    # NOTE: We write the static hostname to /etc/hostname first in case
-    #       hostnamectl fails. Fallback-code below will then adjust the running
-    #       hostname below.
-    echo "echo '$name_should' >/etc/hostname"
-
-    echo "hostnamectl set-hostname '$name_should' && exit 0"
-fi
-
-# Use the good old way to set the hostname. Also if hostnamectl fails.
 case $os
 in
-    alpine|archlinux|debian|devuan|ubuntu)
+    alpine|debian|devuan|ubuntu)
-        echo "echo '$name_should' >/etc/hostname"
+        echo 'hostname -F /etc/hostname'
-        echo "hostname -F /etc/hostname"
     ;;
-    coreos|openbmc-phosphor)
+    archlinux|centos|fedora|redhat|scientific|freebsd|netbsd|gentoo)
-        # NOTE: systemd-only distros have the hostname already written above.
-        #       But since hostamectl failed, we update the running hostname
-        #       manually.
-        echo "hostname -F /etc/hostname"
-        ;;
-    gentoo)
-        # NOTE: Writing the hostname to file is done in the manifest for OpenRC.
-        #       For systemd hostnamectl should take care of that.
         echo "hostname '$name_should'"
     ;;
     macosx)
         echo "scutil --set HostName '$name_should'"
     ;;
+    openbsd)
+        echo 'hostname -F /etc/myname'
+    ;;
     suse)
-        # We write into /etc/HOSTNAME for backwards-compatibility.  Modern SuSE
-        # has hostnamectl anyway and symlinks /etc/HOSTNAME to /etc/hostname.
-        echo "echo '$name_should' >/etc/HOSTNAME"
         echo 'hostname -F /etc/HOSTNAME'
     ;;
-    centos|fedora|freebsd|netbsd|openbsd|redhat|scientific)
-        # NOTE: Writing the hostname to file is done in the manifest.
-        echo "hostname '$name_should'"
-    ;;
     *)
-        echo "echo 'Unsupported OS: $os' >&2; exit 1"
+        # Fall back to set the hostname using hostnamectl, if available.
+        if test -n "$has_hostnamectl"
+        then
+            # Don't use hostnamectl as the primary means to set the hostname for
+            # systemd systems, because it cannot be trusted to work reliably and
+            # exit with non-zero when it fails.
+            # Who invented a tool that needs dbus to set the hostname anyway…
+
+            echo "hostnamectl set-hostname \"\$(cat /etc/hostname)\""
+            echo "test \"\$(hostname)\" = \"\$(cat /etc/hostname)\" || hostname -F /etc/hostname"
+        else
+            printf "echo 'Unsupported OS: %s' >&2\nexit 1\n" "$os"
+        fi
     ;;
 esac

cdist/conf/type/__hostname/manifest

@@ -20,18 +20,25 @@
 # along with cdist. If not, see <http://www.gnu.org/licenses/>.
 #
 
+onchange_cmd="echo changed >>'$__messages_out'"
+
 not_supported() {
     echo "Your operating system ($os) is currently not supported by this type (${__type##*/})." >&2
     echo "Please contribute an implementation for it if you can." >&2
     exit 1
 }
 
+set_hostname_systemd() {
+    echo "$1" | __file /etc/hostname --source - --onchange "$onchange_cmd"
+}
 
 os=$(cat "$__global/explorer/os")
 max_len=$(cat "$__object/explorer/max_len")
+has_hostnamectl=$(cat "$__object/explorer/has_hostnamectl")
 
-if [ -f "$__object/parameter/name" ]; then
+if test -s "$__object/parameter/name"
-    name_should="$(cat "$__object/parameter/name")"
+then
+    name_should=$(cat "$__object/parameter/name")
 else
     case $os
     in
@@ -55,12 +62,31 @@ fi
 
 case $os
 in
-    archlinux|debian|suse|ubuntu|devuan|coreos|alpine|macosx)
+    alpine|debian|devuan|ubuntu)
+        echo "$name_should" \
+            | __file /etc/hostname --source - --onchange "$onchange_cmd"
+    ;;
+    macosx)
         # handled in gencode-remote
         :
     ;;
+    archlinux)
+        if test -n "$has_hostnamectl"
+        then
+            set_hostname_systemd "$name_should"
+        else
+            # Only for ancient ArchLinux, write to /etc/rc.conf on pre-systemd
+            # versions.
+            __key_value sysconfig-hostname \
+                --file /etc/rc.conf \
+                --delimiter '=' --exact_delimiter \
+                --key 'HOSTNAME' \
+                --value "\"$name_should\"" \
+                --onchange "$onchange_cmd"
+        fi
+        ;;
     centos|fedora|redhat|scientific)
-        if test -z "$(cat "$__object/explorer/has_hostnamectl")"
+        if test -z "$has_hostnamectl"
         then
             # Only write to /etc/sysconfig/network on non-systemd versions.
             # On systemd-based versions this entry is ignored.
@@ -68,11 +94,14 @@ in
                 --file /etc/sysconfig/network \
                 --delimiter '=' --exact_delimiter \
                 --key HOSTNAME \
-                --value "\"$name_should\""
+                --value "\"$name_should\"" \
+                --onchange "$onchange_cmd"
+        else
+            set_hostname_systemd "$name_should"
         fi
     ;;
     gentoo)
-        if test -z "$(cat "$__object/explorer/has_hostnamectl")"
+        if test -z "$has_hostnamectl"
         then
             # Only write to /etc/conf.d/hostname on OpenRC-based installations.
             # On systemd use hostnamectl(1) in gencode-remote.
@@ -81,6 +110,8 @@ in
                 --delimiter '=' --exact_delimiter \
                 --key 'hostname' \
                 --value "\"$name_should\""
+        else
+            set_hostname_systemd "$name_should"
         fi
     ;;
     freebsd)
@@ -88,22 +119,37 @@ in
             --file /etc/rc.conf \
             --delimiter '=' --exact_delimiter \
             --key 'hostname' \
-            --value "\"$name_should\""
+            --value "\"$name_should\"" \
+            --onchange "$onchange_cmd"
     ;;
     netbsd)
         __key_value rcconf-hostname \
             --file /etc/rc.conf \
             --delimiter '=' --exact_delimiter \
             --key 'hostname' \
-            --value "\"$name_should\""
+            --value "\"$name_should\"" \
+            --onchange "$onchange_cmd"
+
         # To avoid confusion, ensure that the hostname is only stored once
         __file /etc/myname --state absent
     ;;
     openbsd)
-        echo "$name_should" | __file /etc/myname --source -
+        echo "$name_should" \
+            | __file /etc/myname --source - --onchange "$onchange_cmd"
+    ;;
+    suse)
+        # We write into /etc/HOSTNAME for backwards-compatibility.  Modern SuSE
+        # has hostnamectl anyway and symlinks /etc/HOSTNAME to /etc/hostname.
+        echo "$name_should" \
+            | __file /etc/HOSTNAME --source - --onchange "$onchange_cmd"
     ;;
     *)
-        # On other operating systems we fall back to hostnamectl if available…
+        # On other operating systems we fall back to systemd's hostnamectl if available…
-        test -n "$(cat "$__object/explorer/has_hostnamectl")" || not_supported
+        if test -n "$has_hostnamectl"
+        then
+            set_hostname_systemd "$name_should"
+        else
+            not_supported
+        fi
     ;;
 esac