From:	sos AT prospect DOT com DOT ru (Sergey Okhapkin)
Subject:	RE: spawn memory leak?
7 Jun 1998 13:36:59 -0700 :
Message-ID:	<01BD9273.355A3300.cygnus.cygwin32.developers@sos>
To:	"'Tim Newsham'" <newsham AT lava DOT net>
Cc:	"cygwin32-developers AT cygnus DOT com" <cygwin32-developers AT cygnus DOT com>

Tim Newsham wrote:
> For those who cry "this only works for cygwin processes!", yes, true,
> but it is better than not working at all.  BUT... there seems to be
> a way to do close-on-exec even when spawn()'ing non cygwin programs:
>
>     foreach close-on-exec fd
>         save old handle flags
>         set handle flag to non-inheritable
>     build new fd table for child process without entries for these fd's
>     CreateProcess, passing down new table (not simply passing dup of 
parents)
>     foreach close-on-exec fd
>         set handle flag to saved value
>
> this of course only works on systems that support the 
SetHandleInformation
> call, but imo, its better than not supporting it on any system at all.
>

I see another simple solution - functions pinfo::init_from_exec() and 
hinfo_vec::dup_for_exec() should be removed, and 
hinfo_vec::linearize_fd_array() should be modified to ignore fds with 
close_on_exec set. The single line will be modified (hinfo.cc, line 413):

from
      if (vec[i].is_open ())
to
      if (vec[i].is_open () && !vec[i].h->get_close_on_exec ())

This will solve a problem with a failing spawn()/exec() also. But one more 
problem will arise - the os handles of these fds will be inheritted by 
spawned child :-( Probably, it would be better to leave linearize_fd_array 
unchanged an handle these fds in a child's delinearization code?

--
Sergey Okhapkin, http://www.lexa.ru/sos
Moscow, Russia

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