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authorPhilippe Mathieu-Daudé <philmd@redhat.com>2019-03-07 15:28:21 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2019-03-11 16:33:49 +0100
commit02cdcc96be77a5fdcb1647eb399efef37c107986 (patch)
treef8a90dd5ed8e7ce40aadea738e4deb89683a4f7a /util/oslib-posix.c
parentb0c214ce4145e35a39362b8a3da88b4908ca7c71 (diff)
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oslib-posix: Ignore fcntl("/dev/null", F_SETFL, O_NONBLOCK) failure
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> Message-Id: <20190307142822.8531-2-philmd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'util/oslib-posix.c')
-rw-r--r--util/oslib-posix.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 37c5854..326d92d 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)