v3: Fix mingw build. [patchew] v2: Probe /dev/null to save LOC. [Eric] Mention "new glibc + old kernel" in commit message. [Kevin, Daniel, Eric, Christian]
This fixes the image opening failure reported by Andrew Baumann: > I'm running a recent Linux build of qemu on Windows Subsystem for Linux (WSL) > which doesn't appear to implement file locking: > > $ qemu-system-aarch64 ... -drive file=test.vhdx,if=none,id=hd0 -device > virtio-blk-pci,drive=hd0 > qemu-system-aarch64: -drive file=test.vhdx,if=none,id=hd0: Failed to unlock > byte 100 > qemu-system-aarch64: -drive file=test.vhdx,if=none,id=hd0: Failed to unlock > byte 100 > qemu-system-aarch64: -drive file=test.vhdx,if=none,id=hd0: Failed to lock > byte 100 It appears to be that the binary is built for Linux targets, but the WSL runtime doesn't recognize the ops (-EINVAL). This is also a practical problem for Linux considering it's possible to run QEMU which is built against a new glibc on an old kernel that doesn't have OFD API. Convert to runtime check to cope with that. Fam Zheng (2): osdep: Add runtime OFD lock detection file-posix: Do runtime check for ofd lock API block/file-posix.c | 19 +++++++-------- include/qemu/osdep.h | 1 + util/osdep.c | 66 ++++++++++++++++++++++++++++++++++++++++++++-------- 3 files changed, 65 insertions(+), 21 deletions(-) -- 2.13.4