From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:46178) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1u0l-0004Wt-Kz for qemu-devel@nongnu.org; Thu, 07 Mar 2019 09:28:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h1u0j-0008B7-Ky for qemu-devel@nongnu.org; Thu, 07 Mar 2019 09:28:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35960) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h1u0h-00086J-Pg for qemu-devel@nongnu.org; Thu, 07 Mar 2019 09:28:37 -0500 From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Thu, 7 Mar 2019 15:28:21 +0100 Message-Id: <20190307142822.8531-2-philmd@redhat.com> In-Reply-To: <20190307142822.8531-1-philmd@redhat.com> References: <20190307142822.8531-1-philmd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v3 1/2] oslib-posix: Ignore fcntl("/dev/null", F_SETFL, O_NONBLOCK) failure List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Brad Smith , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , "Michael S . Tsirkin" Previous to OpenBSD 6.3 [1], fcntl(F_SETFL) is not permitted on memory devices. Trying this call sets errno to ENODEV ("not a memory device"): 19 ENODEV Operation not supported by device. An attempt was made to apply an inappropriate function to a device, for example, trying to read a write-only device such as a printer. Do not assert fcntl failures in this specific case (errno set to ENODEV) on OpenBSD. This fixes: $ lm32-softmmu/qemu-system-lm32 assertion "f !=3D -1" failed: file "util/oslib-posix.c", line 247, func= tion "qemu_set_nonblock" Abort trap (core dumped) [1] The fix seems https://github.com/openbsd/src/commit/c2a35b387f9d3c "fcntl(F_SETFL) invokes the FIONBIO and FIOASYNC ioctls internally, so the memory devices (/dev/null, /dev/zero, etc) need to permit them." Reviewed-by: Peter Maydell Reviewed-by: Michael S. Tsirkin Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- util/oslib-posix.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 37c5854b9c..326d92dcd2 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -244,7 +244,19 @@ void qemu_set_nonblock(int fd) f =3D fcntl(fd, F_GETFL); assert(f !=3D -1); f =3D fcntl(fd, F_SETFL, f | O_NONBLOCK); +#ifdef __OpenBSD__ + if (f =3D=3D -1) { + /* + * Previous to OpenBSD 6.3, fcntl(F_SETFL) is not permitted on + * memory devices and sets errno to ENODEV. + * It's OK if we fail to set O_NONBLOCK on devices like /dev/nul= l, + * because they will never block anyway. + */ + assert(errno =3D=3D ENODEV); + } +#else assert(f !=3D -1); +#endif } =20 int socket_set_fast_reuse(int fd) --=20 2.20.1