[Qemu-devel] Re: [PATCH] osdep: Fix runtime failure on older Linux kernels

[Paolo Bonzini <pbonzini@redhat.com>]

On 12/18/2009 10:45 AM, Andre Przywara wrote:
> If QEMU finds newer kernel header files on compilation time, it will use
> advertised features like pipe2 or SOCK_CLOEXEC by just doing a compile test.
> If later the executables are executed on an older kernel (<2.6.27,
> like Xen Dom0 2.6.18), then QEMU will fail on opening sockets and creating
> pipes and returns the rather unspecific "qemu_init_main_loop failed".
> This patch fixes this by checking the return values of these calls
> for EINVAL and ENOSYS and falling back to the older versions automatically.

Agreed, most other apps that use *_CLOEXEC do this (including glibc 
itself and gnulib; the notable exception is APR and there were quite 
some flames about this).

Paolo