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From: Martin Buchholz <martinrb@google.com>
Date: Wed, 12 Sep 2018 19:46:00 -0000
Message-ID: <CA+kOe0-CvUou3Au4y+niES8OnspG==mVE6YKbQXpAZ-wmcPPDw@mail.gmail.com>
Subject: Re: system and popen fail in case of big application
To: Zack Weinberg <zackw@panix.com>
Cc: adhemerval.zanella@linaro.org, GNU C Library <libc-alpha@sourceware.org>
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On Wed, Sep 12, 2018 at 9:29 AM, Zack Weinberg <zackw@panix.com> wrote:
> I don't want to encourage people to use posix_spawn because
> posix_spawn is a badly designed API.  It's difficult to use correctly.
> It's *tedious* to use correctly, which means people won't bother.  It
> can't do everything you might want to do on the child side (witness
> the discussion of adding an extension to let it do chdir()).  Its
> behavior in case of errors is underspecified.  And it might be
> implemented in terms of fork, which means it doesn't guarantee to
> solve Sergey's problem.

I seem to be in agreement with Zack's eloquent post.  From java's
point of view, we need to avoid the momentary doubling of memory
caused by fork()ing a huge process, and we need to be able to specify
a working directory for the child.  One strategy is to use posix_spawn
to start a small helper process which then in turn execs the real
child after necessary set up (including chdir).