[Tarantool-patches] [PATCH 1/5] popen: Introduce a backend engine

[Cyrill Gorcunov]

On Fri, Nov 29, 2019 at 08:52:14AM +0300, Konstantin Osipov wrote:
> * Cyrill Gorcunov <gorcunov at gmail.com> [19/11/28 23:46]:
> >  - environment variables are flushed to zero, should we provide
> >    a way to adjust it (via options) or inherit it instead?
> 
> Yes. You can take a look at Python Popen api for inspiration.

Will do, thanks!

> 
> >  - popen_kill always send SIGKILL, should not we provide a
> >    portable way to customize signal sedning (say symbolic
> >    names for signals and pass them here)?
> 
> Again, you could take a look at Python - they have kill()
> and terminate(), which allows for platform-agnostics hard and soft 
> termination. Sending Unix signals to processes can be done by signal()
> system call, so you don't need to worry about providing an API
> for it in Popen, as long as you expose the child pid in the api.
> 
> >  - for native mode we don't do additional processing of arguments
> >    thus only plain name of elf executable will be working, we
> >    should provide a way for argv explicit passing or
> >    do analyze @command for arguments by hands;
> 
> >  - need to consider a case where we will be using piping for
> >    descriptors (for example we might be writting into stdin
> >    of a child from another pipe, for this sake we could use
> >    splice() syscall which gonna be a way faster than copying
> >    data inside kernel between process). Still the question
> >    is -- do we really need it? Since we use interanal flags
> >    in popen handle this should not be a big problem to extend
> >    this interfaces.
> 
> Not in the first version for sure. 

Yup. But you know I think of a future enhancement, and if I not
missing something obvious there still enough place in @flags
so we will be able to mark every stdX as a pipe and handle
accordingly.

> >  	title_free(main_argc, main_argv);
> >  
> > +	popen_fini();
> 
> The convention is to use new/delete for functions which
> allocate + initialize and destroy + deallocate an object.
> 
> create/destroy for functions which initialize/destroy an object
> but do not handle memory management.
> 
> init/free for functions which initialize/destroy libraries and
> subsystems. Please stick to it.

Sure, thanks!

	Cyrill