[PATCH 5/8] posix: Do not clobber errno by atfork handlers

[Florian Weimer]

* Adhemerval Zanella via Libc-alpha:

> Checked on x86_64-linux-gnu.
> ---
>  posix/fork.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/posix/fork.c b/posix/fork.c
> index 4c9e60f187..7f27fb8338 100644
> --- a/posix/fork.c
> +++ b/posix/fork.c
> @@ -68,7 +68,7 @@ __libc_fork (void)
>      }
>  
>    pid_t pid = _Fork ();
> -
> +  int save_errno = errno;
>    if (pid == 0)
>      {
>        /* Reset the lock state in the multi-threaded case.  */
> @@ -107,6 +107,8 @@ __libc_fork (void)
>    __run_fork_handlers (pid == 0 ? atfork_run_child : atfork_run_parent,
>  		       multiple_threads);
>  
> +  if (pid < 0)
> +    __set_errno (save_errno);
>    return pid;
>  }
>  weak_alias (__libc_fork, __fork)

Why is this condition correct?  Shouldn't it be pid >= 0?

I wonder if this should be part of __run_fork_handlers, so that fork
handlers always observe the original errno value.

Thanks,
Florian