[__hostname] Better support different versions of SuSE

cdist/conf/type/__hostname/gencode-remote

@@ -66,7 +66,7 @@ in
             "&& hostnamectl set-hostname '$name_should'" \
             "|| hostname '$name_should'"
     ;;
-    centos|fedora|redhat|scientific|freebsd|netbsd|openbsd|gentoo|slackware|void)
+    centos|fedora|redhat|scientific|freebsd|netbsd|openbsd|gentoo|void)
         echo "hostname '$name_should'"
     ;;
     macosx)
@@ -75,8 +75,11 @@ in
     solaris)
         echo "uname -S '$name_should'"
     ;;
-    suse)
+    slackware|suse|opensuse-leap)
-        echo 'hostname -F /etc/HOSTNAME'
+        # We do not read from /etc/HOSTNAME, because the running
+        # hostname is the first component only while the file contains
+        # the FQDN.
+        echo "hostname '$name_should'"
     ;;
     *)
         # Fall back to set the hostname using hostnamectl, if available.
@@ -84,11 +87,12 @@ in
         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.
+            # exit with non-zero when it fails (e.g. hostname too long,
-            # Who invented a tool that needs dbus to set the hostname anyway…
+            # D-Bus failure, etc.).
 
             echo "hostnamectl set-hostname \"\$(cat /etc/hostname)\""
-            echo "test \"\$(hostname)\" = \"\$(cat /etc/hostname)\" || hostname -F /etc/hostname"
+            echo "test \"\$(hostname)\" = \"\$(cat /etc/hostname)\"" \
+                 " || hostname -F /etc/hostname"
         else
             printf "echo 'Unsupported OS: %s' >&2\nexit 1\n" "$os"
         fi

cdist/conf/type/__hostname/manifest

@@ -31,6 +31,9 @@ set_hostname_systemd() {
 }
 
 os=$(cat "$__global/explorer/os")
+os_version=$(cat "$__global/explorer/os_version")
+os_major=$(echo "$os_version" | grep -o '^[0-9][0-9]*')
+
 max_len=$(cat "$__object/explorer/max_len")
 has_hostnamectl=$(cat "$__object/explorer/has_hostnamectl")
 
@@ -45,8 +48,21 @@ else
             # Hostname is FQDN
             name_should="${__target_host}"
         ;;
+        suse|opensuse-leap)
+            # Classic SuSE stores the FQDN in /etc/HOSTNAME, while
+            # systemd does not. The running hostname is the first
+            # component in both cases.
+            # In versions before 15.x, the FQDN is stored in /etc/hostname.
+            if test -n "$has_hostnamectl" && test "$os_major" -ge 15 \
+                    && test "$os_major" -ne 42
+            then
+                name_should="${__target_host%%.*}"
+            else
+                name_should="${__target_host}"
+            fi
+        ;;
         *)
-            # Hostname is only first component of FQDN
+            # Hostname is only first component of FQDN on all other systems.
             name_should="${__target_host%%.*}"
         ;;
     esac
@@ -127,28 +143,42 @@ in
             --key 'hostname' \
             --value "\"$name_should\""
 
-        # To avoid confusion, ensure that the hostname is only stored once
+        # To avoid confusion, ensure that the hostname is only stored once.
         __file /etc/myname --state absent
     ;;
     openbsd)
         echo "$name_should" | __file /etc/myname --source -
     ;;
     slackware)
-        # We write the FQDN into /etc/HOSTNAME.
+        # We write the FQDN into /etc/HOSTNAME.  But /etc/rc.d/rc.M will only
-        # But /etc/rc.d/rc.M will only read the first component from this file
+        # read the first component from this file and set it as the running
-        # and set it as the running hostname on boot.
+        # hostname on boot.
         echo "$name_should" | __file /etc/HOSTNAME --source -
     ;;
     solaris)
         echo "$name_should" | __file /etc/nodename --source -
     ;;
-    suse)
+    suse|opensuse-leap)
-        # We write into /etc/HOSTNAME for backwards-compatibility.  Modern SuSE
+        # Modern SuSE provides /etc/HOSTNAME as a symlink for
-        # has hostnamectl anyway and symlinks /etc/HOSTNAME to /etc/hostname.
+        # backwards-compatibility. Unfortunately it cannot be used
-        echo "$name_should" | __file /etc/HOSTNAME --source -
+        # here as __file does not follow the symlink.
+        # Therefore, we use the presence of the hostnamectl binary as
+        # an indication of which file to use.  This unfortunately does
+        # not work correctly on openSUSE 12.x which provides
+        # hostnamectl but not /etc/hostname.
+
+        if test -n "$has_hostnamectl" -a "$os_major" -gt 12
+        then
+            hostname_file='/etc/hostname'
+        else
+            hostname_file='/etc/HOSTNAME'
+        fi
+
+        echo "$name_should" | __file "$hostname_file" --source -
     ;;
     *)
-        # On other operating systems we fall back to systemd's hostnamectl if available…
+        # On other operating systems we fall back to systemd's
+        # hostnamectl if available…
         if test -n "$has_hostnamectl"
         then
             set_hostname_systemd "$name_should"