| Message ID | 20190307142822.8531-2-philmd@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | OpenBSD: Let QEMU 4.0 be usable from OpenBSD 6.0 and onwards | expand |
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 = fcntl(fd, F_GETFL); assert(f != -1); f = fcntl(fd, F_SETFL, f | O_NONBLOCK); +#ifdef __OpenBSD__ + if (f == -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/null, + * because they will never block anyway. + */ + assert(errno == ENODEV); + } +#else assert(f != -1); +#endif } int socket_set_fast_reuse(int fd)
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 != -1" failed: file "util/oslib-posix.c", line 247, function "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 <peter.maydell@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> --- util/oslib-posix.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)