commit c88619fdecc799c38a95df5489a4fa09de09e71e
author Milton D. Miller II <miltonm@us.ibm.com> Wed Mar 02 18:28:54 2016 -0600
committer Milton D. Miller II <miltonm@us.ibm.com> Fri Mar 04 11:25:38 2016 -0600
tree 52eea1931c3441e518a347c76b14076e8d3ffb90
parent c77c92ac0fe2b2fa48d36190cee934359960d88e

init: Add a hook to download files

Add a hook to run a shell command line that is stored in a u-boot
environment variable.  Only execute this command if the previously
established options file has a keyword trigger.  Do not even consider
the option if a build option flag is not set to y.

This allows one to specify at u-boot commands that would download
a read-only file system into memory for execution this boot instead
of needing to create a custom initramfs to netboot or specifing
debug-init-sh, entering the password, and doing the download from
the shell.

If the u-boot environment variable is empty or missing but both
the build variable is set and the keyword trigger are set print
a diagnostic message.  If the command fails invoke standard
debug_takeover for corrective action.

An example script:
fw_setenv openbmcinitdownload 'cp /proc/net/pnp /run/resolv.conf ; ln -snf ../run/resolv.conf /etc/resolv.conf ; wget -O /run/image-rofs http://server.example.com/path/image-test-rofs'