file locking

[rd235]

File locking is not currently supported in vuos
Unfortunately there are many file locking APIs: fcntl, flock...

[andriyolo]

I have some questions regarding this feature implementation:

• when a locking SC should be virtualized? Always, in some cases (and what would these be?), ...
• how can we define such cases? Using a system like vufs to virtualize only the locking SCs which use a file descriptor of a file in the virtualized tree?
• what locking SCs should be virtualized? All, just the ones that shouldn't be allowed, ... ?
• where does the code should be placed? In a (sub)module, as part of VUOS, ... ?

These are the first questions that come to mind when thinking about this feature.
I'd be happy to at least write a first implementation for this functionality but I need more info about it and some tips on how to start.

[andriyolo]

PR #21 addresses this