logfiles - get rid of external cat

[PeterPitterling]

No description provided.

[fmherschel]

@angelabriel: Here is fork vs fork (so not a real improvement in that direction), but less good to read. It's a bit more about code style.

[fmherschel]

Maybe (after testing) would be OK, if we implement the read-from-file as a function. In that case the entire code gets more readable.

[PeterPitterling]

@angelabriel: Here is fork vs fork (so not a real improvement in that direction), but less good to read. It's a bit more about code style.

There is a difference .. fork yes, but (<..) avoids execve
https://stackoverflow.com/questions/51937702/what-is-the-difference-between-cat-file-file-and-read-file-f

[fmherschel]

I have added that code change for angi (crossported) for classic I would not like to add this code change as we would need to test that with all old SLES versions a customer still could run. Even, if they run an outdated SLES version I would not like to break their environment just for code style. For angi we could trust in versions could only be SLE15SP4 and newer. So that was more easy to test.
I vote for closing this PR (done for angi in the lib (commit #71762602444853197dbc7f07231f20de68ba8f26) and reject for classic).