[RFC PATCH 2/2] meta: add isar-cfg-hostname recipe for setting the hostname

[claudius.heine.ext@siemens.com]

From: Claudius Heine <ch@denx.de>

The isar-cfg-hostname recipe is a central point to set the hostname
for images. It provides the `CFG_HOSTNAME` variables, which can be set
from any `.conf` file or via `isar-cfg-hostname.bbappend` to the
hostname that should be used. The default is 'isar'.

Signed-off-by: Claudius Heine <ch@denx.de>
---
 meta-isar/conf/local.conf.sample                 |  2 +-
 meta-isar/recipes-app/example-raw/files/postinst |  2 --
 .../isar-cfg-hostname/files/postinst.tmpl        |  8 ++++++++
 .../isar-cfg-hostname/isar-cfg-hostname.bb       | 16 ++++++++++++++++
 4 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100644 meta/recipes-support/isar-cfg-hostname/files/postinst.tmpl
 create mode 100644 meta/recipes-support/isar-cfg-hostname/isar-cfg-hostname.bb

diff --git a/meta-isar/conf/local.conf.sample b/meta-isar/conf/local.conf.sample
index a2bdd7e..ddd15a4 100644
--- a/meta-isar/conf/local.conf.sample
+++ b/meta-isar/conf/local.conf.sample
@@ -162,7 +162,7 @@ CONF_VERSION = "1"
 #
 # The default list of extra packages to be installed.
 IMAGE_INSTALL = "hello-isar example-raw example-module-${KERNEL_NAME} enable-fsck \
-                 isar-cfg-rootpw"
+                 isar-cfg-rootpw isar-cfg-hostname"
 
 #
 # Enable cross-compilation support
diff --git a/meta-isar/recipes-app/example-raw/files/postinst b/meta-isar/recipes-app/example-raw/files/postinst
index f48d993..a28afa3 100644
--- a/meta-isar/recipes-app/example-raw/files/postinst
+++ b/meta-isar/recipes-app/example-raw/files/postinst
@@ -14,5 +14,3 @@ if ! getent passwd isar >/dev/null; then
 fi
 
 chown -R isar:isar /var/lib/isar
-
-echo "isar" > /etc/hostname
diff --git a/meta/recipes-support/isar-cfg-hostname/files/postinst.tmpl b/meta/recipes-support/isar-cfg-hostname/files/postinst.tmpl
new file mode 100644
index 0000000..b46433b
--- /dev/null
+++ b/meta/recipes-support/isar-cfg-hostname/files/postinst.tmpl
@@ -0,0 +1,8 @@
+#!/bin/sh
+set -e
+if [ ! -e "/etc/hostname"  ]; then
+    echo "${CFG_HOSTNAME}" > /etc/hostname
+else
+    echo "/etc/hostname already exists, error" >&2
+    exit -1
+fi
diff --git a/meta/recipes-support/isar-cfg-hostname/isar-cfg-hostname.bb b/meta/recipes-support/isar-cfg-hostname/isar-cfg-hostname.bb
new file mode 100644
index 0000000..aa41f73
--- /dev/null
+++ b/meta/recipes-support/isar-cfg-hostname/isar-cfg-hostname.bb
@@ -0,0 +1,16 @@
+# This software is a part of ISAR.
+
+DESCRIPTION = "Isar configuration package for hostname"
+MAINTAINER = "isar-users <isar-users@googlegroups.com>"
+
+SRC_URI = "file://postinst.tmpl"
+
+TEMPLATE_FILES = "postinst.tmpl"
+TEMPLATE_VARS = "CFG_HOSTNAME"
+CFG_HOSTNAME ??= "isar"
+
+inherit dpkg-raw
+
+do_install() {
+    echo "intentionally left blank"
+}
-- 
2.20.1