[Nix-dev] Make wrappers be binaries instead of shell scripts?

[Shea Levy]

Some time ago I had an idea for a ‘wrapper interpreter’, seems like execline might be similar. No reason we can’t have such a thing.

> On Nov 18, 2014, at 9:02 AM, Thomas Tuegel <ttuegel at gmail.com> wrote:
> 
> On Tue, Nov 18, 2014 at 7:32 AM, Wout Mertens <wout.mertens at gmail.com> wrote:
>> Hi all,
>> 
>> I'm wondering if it wouldn't be better to make the application wrapper
>> scripts generated by makeWrapper be binaries that do the environment
>> massaging and config in binary code before exec() ing the wrapped program.
>> 
>> The advantages would be that the wrapper itself loads very fast since all
>> the shell init and shell parsing is skipped. You also get precise control
>> over the execv() call or other desired factors.
> 
> I was discussing this on #nixos yesterday in light of a long standing
> bug in our wrapper for Hoogle. Hoogle requires its arguments in a very
> specific order, so it has a custom wrapper which had a bug because I
> didn't fully understand the vagaries of $@ versus "$@" in bash. My
> point being, I think precision is the stronger argument here.
> 
>> The disadvantages are that you can't read what a wrapper does and the
>> wrapper file is bigger (about 4KB in my tests for a simple execv()).
> 
> The middle ground here would be to use something like execline [1]
> which avoids the overhead of loading a traditional shell, but still
> reads a human-inspectable script.
> 
>> Thoughts?
>> 
>> Wout.
>> 
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> 
> [1] http://skarnet.org/software/execline/
> 
> -- 
> Thomas Tuegel
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