Hi,
On 1/15/19 9:04 PM, Michael S. Tsirkin wrote:
From: Li Qiang <address@hidden>
Assert that the return value is not an error. This is like commit
7e6478e7d4f for qemu_set_cloexec.
Signed-off-by: Li Qiang <address@hidden>
Reviewed-by: Thomas Huth <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
util/oslib-posix.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index c1bee2a581..4ce1ba9ca4 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -233,14 +233,18 @@ void qemu_set_block(int fd)
{
int f;
f = fcntl(fd, F_GETFL);
- fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
+ assert(f != -1);
+ f = fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
+ assert(f != -1);
}
void qemu_set_nonblock(int fd)
{
int f;
f = fcntl(fd, F_GETFL);
- fcntl(fd, F_SETFL, f | O_NONBLOCK);
+ assert(f != -1);
+ f = fcntl(fd, F_SETFL, f | O_NONBLOCK);
+ assert(f != -1);
This commit breaks OpenBSD, when trying to start QEMU I get:
assertion "f != -1" failed: file "util/oslib-posix.c", line 247,
function "qemu_set_nonblock"
Having a quick look at gdb, the last device opened is /dev/null, and
when fcntl() fails we have errno = ENODEV.
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.
Digging further I found a recent commit which could fix this problem:
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."
Brad: Do you think this might be the fix? If so, any idea what is the
first release to contain this fix? I don't know OpenBSD and can't figure
this out... Also, what would be the cleaner QEMU fix?