Fix #5, Remove OS_OpenCreate file status check in SC_LoadDefaultTables

[thnkslprpt]

Checklist

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution

• Fixes Use OS_stat to verify file existence #5
  • Call to OS_OpenCreate() in the SC_LoadDefaultTables() function converted to OS_stat().

Testing performed
GitHub CI actions (incl. Build + Run, Unit Tests etc.) all passing successfully.

Expected behavior changes
Simplifies function and eases future maintenance.

Contributor Info
Avi Weiss @thnkslprpt

[jphickey]

I'm not convinced this check should even be in there at all - no matter which function is used, its a race condition, due to the difference between the time of check and time of use.

That is, CFE_TBL_Load() will open the file again, and it should handle the error if it is not able to open it. SC should just check for that possible result - it shouldn't do its own check to avoid that result, because any such attempt would be incomplete and a race condition.

As this change set stands right now, while OS_stat() is lighter weight, it only verifies that the file exists, it does not verify that the file is readable.

I think we should simplify this, and remove this extra check.

[thnkslprpt]

I'm not convinced this check should even be in there at all...

Great!
Updated.

[jphickey]

I like this simplification, but we need to check if this affects any of the build verification tests.

I think we should merge it but we need to note this may need a corresponding test update to go with it.

[jphickey]

Thanks for the update, I still think we should merge this one. Will bring it up at the next review.