Initial Functionality

This is the first release of xrdhttp-pelican, corresponding with the initial functionality of the plugin.

The xrdhttp-pelican plugin will listen on a socket provided by the parent process and:

• Shutdown xrootd when the parent process dies.
• Update xrootd's certificate file when instructed
• Update xrootd's host certificate when instructed

The intent of the plugin is to provide a way for a parent process which has dropped privileges to shutdown and perform maintenance on the xrootd proces.