B #163: Enable services on upgrade

Also enables support for Alpine post-upgrade script with warning
if it's necessary to run update-conf to apply new version of files
in /etc:

```
...
Executing one-context-6.1.80-r0.20210809gitbcd3c5b.post-upgrade
WARNING: Run update-conf to process any updated one-context files in /etc!
Executing busybox-1.33.1-r2.trigger
Executing eudev-3.2.10-r0.trigger
OK: 148 MiB in 118 packages

$ update-conf -l
//etc/one-context.d/loc-09-timezone
//etc/one-context.d/loc-30-console
//etc/one-context.d/loc-10-network
//etc/one-context.d/loc-16-gen-env
```

Closes #163

pkg/postinstall

@@ -47,6 +47,12 @@ elif which rc-update >/dev/null 2>&1; then
         rc-update add "${S}" boot >/dev/null 2>&1
     done
 
+    # When existing file is changed, the new one might be created with
+    # .apk-new suffix. Such files need to be processed by update-conf.
+    if update-conf -al | grep -q context; then
+        echo 'WARNING: Run update-conf to process any updated one-context files in /etc!' >&2
+    fi
+
 elif [ -x /bin/freebsd-version ]; then
     :
 

pkg/postupgrade

@@ -1,7 +1,56 @@
 #!/usr/bin/env bash
 
+# Reload udev rules
 udevadm control --reload >/dev/null 2>&1 || :
 
-if which systemctl >/dev/null 2>&1 && [ -d /etc/systemd ]; then
+### Enable services ########################################
+
+SERVICES=${SERVICES:-one-context-local one-context-online one-context}
+
+if which systemctl >/dev/null 2>&1 && \
+    [ -d /etc/systemd ] && \
+    [ -f /usr/lib/systemd/system/one-context.service ];
+then
     systemctl daemon-reload >/dev/null 2>&1 || :
+
+    for S in ${SERVICES}; do
+        systemctl enable "${S}.service" >/dev/null 2>&1
+    done
+fi
+
+if which chkconfig >/dev/null 2>&1; then
+    for S in ${SERVICES}; do
+        chkconfig --add "${S}" >/dev/null 2>&1
+    done
+
+    # EL6: refresh initramfs via dracut for growroot module
+    if [ -f /usr/share/dracut/modules.d/50growroot/install ]; then
+        for I in $(find /boot -name 'initramfs-*.img'); do
+            KERNEL_VERS=$(echo "${I}" | sed -e 's/.*initramfs-\(.*\)\.img/\1/')
+            dracut -f "${I}" "${KERNEL_VERS}" || :
+        done
+    fi
+
+elif which update-rc.d >/dev/null 2>&1; then
+    for S in ${SERVICES}; do
+        update-rc.d "${S}" enable   >/dev/null 2>&1
+        update-rc.d "${S}" defaults >/dev/null 2>&1
+    done
+
+elif which rc-update >/dev/null 2>&1; then
+    for S in ${SERVICES}; do
+        rc-update add "${S}" boot >/dev/null 2>&1
+    done
+
+    # When existing file is changed, the new one might be created with
+    # .apk-new suffix. Such files need to be processed by update-conf.
+    if update-conf -al | grep -q context; then
+        echo 'WARNING: Run update-conf to process any updated one-context files in /etc!' >&2
+    fi
+
+elif [ -x /bin/freebsd-version ]; then
+    :
+
+else
+    echo 'WARNING: Contextualization service not enabled automatically' >&2
 fi

targets.sh

@@ -136,7 +136,7 @@ case "${TARGET}" in
         POSTIN=${POSTINST:-pkg/postinstall}
         PREUN=${PREUN:-pkg/preuninstall}
         POSTUN=${POSTUN:-pkg/postuninstall}
-        POSTUP=${POSTUP:-}  # FPM 1.9.3 bug: https://github.com/jordansissel/fpm/blob/v1.9.3/lib/fpm/package/apk.rb#L149
+        POSTUP=${POSTUP:-pkg/postupgrade}
         ;;
 
     'iso')