[v2] vfork_launcher undefined behaviour

[gitmodimo]

In my application stating of multiple processes with vfork_launcher causes exception:

terminate called after throwing an instance of 'boost::wrapexcept<boost::system::system_error>'
  what():  assign: Bad file descriptor [system:9 at ...aarch64-buildroot-linux-gnu/sysroot/usr/include/boost/asio/detail/impl/reactive_descriptor_service.ipp:120:5 in function 'boost::system::error_code boost::asio::detail::reactive_descriptor_service::assign(boost::asio::detail::reactive_descriptor_service::implementation_type&, const native_handle_type&, boost::system::error_code&)']

It seems it is caused by undefined behaviour triggered by child process memory modification. After vfork it is forbidden to modify any memory contents except vfrok return value :

pid = ::vfork();
if (pid == -1)
{
    ...
}
else if (pid == 0)
{
    ctx.notify_fork(BOOST_PROCESS_V2_ASIO_NAMESPACE::execution_context::fork_child);//undefined behaviour??
    ec = detail::on_exec_setup(*this, executable, argv, inits...);
    if (!ec)
        close_all_fds(ec);//undefined behaviour??
    if (!ec)
        ::execve(executable.c_str(), const_cast<char * const *>(argv), const_cast<char * const *>(env));

    BOOST_PROCESS_V2_ASSIGN_EC(ec, errno, system_category())
    detail::on_exec_error(*this, executable, argv, ec, inits...);
    ::exit(EXIT_FAILURE);
    return basic_process<Executor>{exec};
}
ctx.notify_fork(BOOST_PROCESS_V2_ASIO_NAMESPACE::execution_context::fork_parent);

To fix this I removed notify_fork. It seems completely unnecessary since we execve and we do not hold any io_context. Or am I missing something?
Also close_all_fds also modifies memory but it seems there is no problem with that.

[gitmodimo]

Also since child process uses parent's memory we should use _exit instead of exit. Otherwise we will mess up parents process state.
This patch fixed all my issues for now.

0001-Fix-vfork_launcher.patch