tree a073dadfaa7529739187ae7264abc21b881c8b97
parent 11a3aeeae3dc887b889d4086d4d26d95c324c08d
author Tom Cherry <tomcherry@google.com> 1501620623 -0700
committer Tom Cherry <tomcherry@google.com> 1502744859 -0700

init: use Result<T> for builtin functions

We currently throw out the return values from builtin functions and
occasionally log errors with no supporting context.  This change uses
the newly introduced Result<T> class to communicate a successful result
or an error back to callers in order to print an error with clear
context when a builtin fails.

Example:

init: Command 'write /sys/class/leds/vibrator/trigger transient' action=init (/init.rc:245) took 0ms and failed: Unable to write to file '/sys/class/leds/vibrator/trigger': open() failed: No such file or directory

Test: boot bullhead
Merged-In: Idc18f331d2d646629c6093c1e0f2996cf9b42aec
Change-Id: Idc18f331d2d646629c6093c1e0f2996cf9b42aec