Add PEL related methods

This adds 2 methods to retrieve PEL data:
1) GetPEL - This will be for use by the PLDM handler in order to
   get a PEL from the logging daemon when the host asks for one
   based on the PEL ID.  It returns a file descriptor to the PEL
   data, which is a lot faster than returning the whole PEL (up
   to 16KB) over D-Bus.

2) GetPELFromOBMCID - This will be mostly for debug using REST/curl
   before the full Redfish event log implementation is available,
   so one can get PEL data off of the BMC when only the OpenBMC
   event log ID is known.

   A use case could be:  Enumerate /xyz/openbmc_project/logging/entry,
   and then call GetPELFromOBMCID on every event that comes back.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I92ac36cffed7fbee4f25205123c484007cbe9d63
1 file changed