[JENKINS-23273] Make sure instance is always running after upgrade

Changed the chown logic so is only skipped if the configured user and
the owner are the same of the name param (default jenkins)

This way the chown is skipped in the majority of the unneeded cases and
installations while we make sure upgrades still work

rpm/build/SPECS/jenkins.spec

@@ -76,22 +76,46 @@ rm -rf "%{buildroot}"
 /usr/sbin/useradd -g %{name} -s /bin/false -r -c "@@SUMMARY@@" \
 	-d "%{workdir}" %{name} &>/dev/null || :
 
+  # Used to decide later if we should perform a chown in case JENKINS_INSTALL_SKIP_CHOWN is false
+  # Check if a previous installation exists, if so use the configured JENKINS_USER to generate a files file for later use
+  # And check the JENKINS_HOME value and existing owners of work, log and cache dir, need to to this check
+  # here because the %files directive overwrites folder owners, I have not found a simple way to make the
+  # files directive to use JENKINS_USER as owner.
+  if [ -f "/etc/sysconfig/%{name}" ]; then
+      . /etc/sysconfig/%{name}
+      touch /tmp/cacheowner
+      ls -ld /var/cache/%{name} | awk 'NR==1 {print $3}' > /tmp/cacheowner
+      touch /tmp/logowner
+      ls -ld /var/log/%{name} | awk 'NR==1 {print $3}' >  /tmp/logowner
+      touch /tmp/workdirowner
+      ls -ld ${JENKINS_HOME:-%{workdir}}| awk 'NR==1 {print $3}'  > /tmp/workdirowner
+  fi
+
 %post
 /sbin/chkconfig --add %{name}
 
 # Ensure the right ownership on files only if not owned by JENKINS_USER
 . /etc/sysconfig/%{name}
 if test x"$JENKINS_INSTALL_SKIP_CHOWN" != "xtrue"; then
-    owner=$(ls -ld /var/cache/%{name} | awk 'NR==1 {print $3}')
-    if [ "$owner" != "${JENKINS_USER:-%{name}}" ] ; then
+    if [ -f "/tmp/cacheowner" ]; then
+      cacheOwner=$(cat /tmp/cacheowner)
+      rm -f /tmp/cacheowner
+    fi
+    if [ "${JENKINS_USER:-%{name}}" != "%{name}" ] || [ "${cacheOwner:-%{name}}" != "${JENKINS_USER:-%{name}}" ] ; then
         chown -R ${JENKINS_USER:-%{name}} /var/cache/%{name}
     fi
-    owner=$(ls -ld /var/log/%{name} | awk 'NR==1 {print $3}')
-    if [ "$owner" != "${JENKINS_USER:-%{name}}" ] ; then
+    if [ -f "/tmp/logowner" ]; then
+      logOwner=$(cat /tmp/logowner)
+      rm -f /tmp/logowner
+    fi
+    if [ "${JENKINS_USER:-%{name}}" != "%{name}" ] || [ "${logOwner:-%{name}}" != "${JENKINS_USER:-%{name}}" ] ; then
         chown -R ${JENKINS_USER:-%{name}} /var/log/%{name}
     fi
-    owner=$(ls -ld ${JENKINS_HOME:-%{workdir}}| awk 'NR==1 {print $3}')
-    if [ "$owner" != "${JENKINS_USER:-%{name}}" ] ; then
+    if [ -f "/tmp/workdirowner" ]; then
+      workdirOwner=$(cat /tmp/workdirowner)
+      rm -f /tmp/workdirowner
+    fi
+    if [ "${JENKINS_USER:-%{name}}" != "%{name}" ] || [ "${workdirOwner:-%{name}}" != "${JENKINS_USER:-%{name}}" ] ; then
         chown -R ${JENKINS_USER:-%{name}} ${JENKINS_HOME:-%{workdir}}
     fi
 fi