Need help with rc.d script

[Ian Smith]

In freebsd-questions Digest, Vol 701, Issue 2, Message: 18
On Mon, 06 Nov 2017 18:32:17 -0500 Ernie Luzar <luzar722 at gmail.com> wrote:

 > I wrote this sh script today for dynamic dns ip updates.
 > When I use service dynip start command it just hangs there.
 > Need pointer to what I am doing wrong.

I'm going to cut to things that might be problematic ..

 > Script started on Mon Nov  6 18:19:18 2017
 > /root/bin >cat /usr/local/bin/dynip
 > #!/bin/sh
[..]
 >    elapse_time="10"
 > 
 >    # Find the NIC device name of the NIC connected to the public internet.
 >    # The default interface obtained from route command is the one connected
 >    # to the public internet.
 >    #
 >    nic_devicename="$(route get -inet default 2> /dev/null | \
 >    grep -o "interface.*" | cut -d ' ' -f 2)"

You do not need the outermost double quotes here, and sh could think the 
first one ends at the next one encountered (on "interface).

 >    ##echo "nic_devicename = ${nic_devicename}"
 > 
 > 
 >    # Get the IP address assigned to that NIC device name.
 >    #
 >    nic_ip="$(ifconfig $nic_devicename inet | \
 >    grep -o "inet.*" | cut -d ' ' -f 2)"

Ditto, just not needed, or you can likely use single quotes for'inet.*'

 >    #echo "nic_ip1 = ${nic_ip}"
 > 
 > 
 >    # On start up get the last recorded ip address in use and populate 
 > variable
 >    # with its value.
 >    #
 >    if [ -f "${prev_ip_file}" ]; then
 >       prev_ip="$(cat ${prev_ip_file})"
 >    else
 >       prev_ip="0.0.0.0"
 >       echo "${prev_ip}" > ${prev_ip_file}
 >    fi
 >    #echo "prev_ip = $prev_ip"
 > 
 >    # This is the continuous loop checking the current ip address to
 >    # to determin if it changed.
 >    while [ 1 ]; do

More portable (for any shell) is 'while true; do' .. 

 >      # Get the IP address assigned to that NIC device name.
 >      nic_ip="$(ifconfig $nic_devicename inet | \
 >      grep -o "inet.*" | cut -d ' ' -f 2)"
 >      #echo "nic_ip2 = ${nic_ip}"
 > 
 >      if [ "${prev_ip}" != "${nic_ip}" ]; then
 >        # Update dynamic DNS hosting site with new ip address.
 >        website="https://dynamicdns.park-your-domain.com/update?"
 >        dyn_host="host=home-fbsd&domain=host.xxxxxxx.com"
 >        password="&password=a3e0ffc2274746b29ceaf126d59e51c1"
 >        url="$website$dyn_host$password"
 >        #echo "$url"
 >        /usr/local/bin/wget -O /var/log/namecheap.dynip.update.log -q "$url"
 >        #echo "rtn-code = $?"
 >        if [ $? -ne 0 ]; then
 >          echo "Error: /usr/local/bin/wget command failed."
 >          exit 3
 >        fi
 >      #echo "${nic_ip}" > ${prev_ip_file}
 >      prev_ip="${nic_ip}"
 >      fi
 >      sleep ${elapse_time}
 >    done

You do NOT need to use daemon, all you need to do is replace done with

    done &

and perhaps test to be clear that's working,

    echo "dynip script done"
    exit 0

So that the script and so run_rc_command will complete, leaving the 
"while .. done &" subshell running in background.

cheers, Ian