[Buildroot] [PATCH 1/2] iperf: fix build on !MMU platforms

[Arnout Vandecappelle <arnout@mind.be>]

On 05/07/12 22:47, Peter Korsgaard wrote:
>>>>>> "Thomas" == Thomas Petazzoni<thomas.petazzoni@free-electrons.com>  writes:
>
>   Thomas>  Build tested on sh2a and blackfin architectures.
>
> Thanks. Have you sent these patches upstream?
>
>   Thomas>  ++++ b/src/Listener.cpp
>   Thomas>  +@@ -679,7 +679,11 @@
>   Thomas>  +     pid_t pid;
>   Thomas>  +
>   Thomas>  +     /* Create a child process&  if successful, exit from the parent process */
>   Thomas>  ++#ifndef HAVE_FORK
>   Thomas>  ++    if ( (pid = vfork()) == -1 ) {
>   Thomas>  ++#else
>   Thomas>  +     if ( (pid = fork()) == -1 ) {
>   Thomas>  ++#endif
>   Thomas>  +         fprintf( stderr, "error in first child create\n");
>   Thomas>  +         exit(0);
>
> I believe you aren't allowed to call exit() after vfork (but should use
> _exit() instead).
>
> http://unix.stackexchange.com/questions/5364/why-should-a-child-of-a-vfork-or-fork-call-exit-instead-of-exit

  This particular exit is OK, because it is in the error case.
It's the one below that is not OK.  Or rather, nothing is OK, because
the child process after a vfork is not supposed to do anything except
exec() or _exit() - it certainly shouldn't return from the function.
In fact, on Linux the parent process is suspended until the child either
_exit()s or exec()s, so it doesn't daemonize at all.

  I'm not sure how you can daemonize in a posixly-correct way on a NOMMU
target.  But since we're running on Linux, we can just use daemon(),
right?  Both glibc and uclibc define it AFAIK.

  Regards,
  Arnout

-- 
Arnout Vandecappelle                               arnout at mind be
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Essensium/Mind                                     http://www.mind.be
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