The second argument to ioctl() can be defined as a different type by different libc implementations, and can be a different size on different architectures depending on what type it is defined as. For example, glibc defines it as `unsigned long` which may have a different size on 32-bit vs. 64-bit architectures, and musl libc defines it as `int`.
The Rust libc crate exposes a type `libc::Ioctl` which is defined as the appropriate integer type for the given libc implementation. Using this type for the request argument to `libc::ioctl()` ensures code will compile correctly regardless of architecture and libc implementation. Also, because ioctl request numbers are defined to be 32 bits (regardless of the fact that `unsigned long` might sometimes take 64 bits on some architectures), this patch changes the Rust representation of the bcachefs ioctl numbers to u32 instead of u64. Signed-off-by: Thomas Bertschinger <[email protected]> --- bch_bindgen/src/libbcachefs_wrapper.h | 4 ++-- src/wrappers/handle.rs | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/bch_bindgen/src/libbcachefs_wrapper.h b/bch_bindgen/src/libbcachefs_wrapper.h index bc4658f..128592c 100644 --- a/bch_bindgen/src/libbcachefs_wrapper.h +++ b/bch_bindgen/src/libbcachefs_wrapper.h @@ -33,5 +33,5 @@ MARK_FIX_753(blk_mode_t, BLK_OPEN_READ); MARK_FIX_753(blk_mode_t, BLK_OPEN_WRITE); MARK_FIX_753(blk_mode_t, BLK_OPEN_EXCL); -MARK_FIX_753(__u64, BCH_IOCTL_SUBVOLUME_CREATE); -MARK_FIX_753(__u64, BCH_IOCTL_SUBVOLUME_DESTROY); +MARK_FIX_753(__u32, BCH_IOCTL_SUBVOLUME_CREATE); +MARK_FIX_753(__u32, BCH_IOCTL_SUBVOLUME_DESTROY); diff --git a/src/wrappers/handle.rs b/src/wrappers/handle.rs index 48148a8..60bdedb 100644 --- a/src/wrappers/handle.rs +++ b/src/wrappers/handle.rs @@ -22,7 +22,7 @@ impl BcachefsHandle { /// I/O control commands that can be sent to a bcachefs filesystem /// Those are non-exhaustive -#[repr(u64)] +#[repr(u32)] #[non_exhaustive] pub enum BcachefsIoctl { SubvolumeCreate = BCH_IOCTL_SUBVOLUME_CREATE, @@ -47,7 +47,7 @@ impl BcachefsHandle { /// Type-safe [`libc::ioctl`] for bcachefs filesystems pub fn ioctl(&self, request: BcachefsIoctl, payload: &BcachefsIoctlPayload) -> Result<(), Errno> { let payload_ptr: *const libc::c_void = payload.into(); - let ret = unsafe { libc::ioctl(self.inner.ioctl_fd, request as u64, payload_ptr) }; + let ret = unsafe { libc::ioctl(self.inner.ioctl_fd, request as libc::Ioctl, payload_ptr) }; if ret == -1 { Err(errno::errno()) -- 2.43.0
