Pre-flight Check: Detect z/OSMF state

[1000TurquoisePogs]

This pre-flight check is to ensure that if z/OSMF is required by configuration, that Zowe does not start if z/OSMF is not started, ready, and working.

This could be situations such as if APIML is on and set to use z/OSMF as an authentication provider.

Potentially, somehow, extensions could alert Zowe that they also need z/OSMF, although such a design doesnt exist yet, potentially it could be said within manifest.yaml or by environment variable output during the validate/configure stages of startup.
I would save that for a separate epic.

In this epic, we can use network communication to detect if z/OSMF is running and healthy. Go to expected URLs we will use, see if the HTTP code is good, certificates are good, etc.

Error and tell the user to start z/OSMF if it appears it's not there,
or if z/OSMF if it appears to be unhealthy,
or if the certificates aren't working with zowe's truststore configuration.

[Martin-Zeithaml]

The z/OSMF status can be obtained from control blocks, see REXX example. This can be easily implemented as binary:

/* REXX                                                               */

/* Decimal addresses                                                  */
/* 16         -> CVT                                                  */
/* CVT  + 140 -> ECVT                                                 */
/* ECVT + 976 -> IZUGSP                                               */

CVT@ = c2d(storage(d2x(16),4))
ECVT@ = c2d(storage(d2x(CVT@ + 140),4))
IZUGSP@ = c2d(Storage(d2x(ECVT@ + 976),4))

IZUGSP_STATUS = c2x(storage(d2x(IZUGSP@+8),1))
if bitand(IZUGSP_STATUS, '80') = '80' then do
  IZUGSP_LEN = c2d(storage(d2x(IZUGSP@+10),2))
  if IZUGSP_LEN > 0 then do
    IZUGSP_URI = storage(d2x(IZUGSP@+12),IZUGSP_LEN)
      say IZUGSP_URI
      exit 0
  end
end

exit 1