cannot get real hostname when launching shell script at boot with launchd - macos

Question

I'm trying to run a shell script at boot with launchd, via a plist file in /Library/LaunchDaemons (on 10.8.x, if that matters):
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>testD</string>
<key>ProgramArguments</key>
<array>
<string>/Users/lfriedman/cuda-stuff/sw/gpgpu/build/scripts/testing/testD.sh</string>
</array>
<key>RunAtLoad</key>
<true/>
<key>KeepAlive</key>
<true/>
<key>UserName</key>
<string>lfriedman</string>
<key>AbandonProcessGroup</key>
<false/>
<key>StandardOutPath</key>
<string>/tmp/testD.out</string>
<key>StandardErrorPath</key>
<string>/tmp/testD.err</string>
</dict>
</plist>
Inside the shell script is a call to 'hostname -s'. If I run the script manually, everything works fine. If I run the script via cron, everything works fine. However, when it runs at boot via launchd the value returned from 'hostname -s' is always (erroneously) returned as 'localhost', rather than the actual hostname of the system. If I tweak the plist to run the script at a time other than at bootup, it also does the right thing and returns the actual short hostname of the system. This leads me to think that there's some sort of race condition going on where launchd is firing off its jobs before the network subsystem of the OS is fully running.
Is there some special way to ensure that the OS is "fully" booted before launchd runs a job? Or a way to force a delay inside the plist file before the program is invoked?

Answer 1

Unfortunately, launchd doesn't have a way of setting dependencies, so you'll need to have the delay in your script. In a shell script, an easy way to check for networking is:
#!/bin/bash
# Example Daemon Starter
. /etc/rc.common
CheckForNetwork
while [ "${NETWORKUP}" != "-YES-" ]
do
sleep 5
NETWORKUP=
CheckForNetwork
done
# Now do what you need to do.
You can see more info at the following link:
http://blog.slaunchaman.com/2010/07/01/how-to-run-a-launchdaemon-that-requires-networking/