Vendor things

third-party/vendor/rustix/src/ioctl/linux.rs

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+//! `ioctl` opcode behavior for Linux platforms.
+
+use super::{Direction, RawOpcode};
+use consts::*;
+
+/// Compose an opcode from its component parts.
+pub(super) const fn compose_opcode(
+    dir: Direction,
+    group: RawOpcode,
+    num: RawOpcode,
+    size: RawOpcode,
+) -> RawOpcode {
+    macro_rules! mask_and_shift {
+        ($val:expr, $shift:expr, $mask:expr) => {{
+            ($val & $mask) << $shift
+        }};
+    }
+
+    let dir = match dir {
+        Direction::None => NONE,
+        Direction::Read => READ,
+        Direction::Write => WRITE,
+        Direction::ReadWrite => READ | WRITE,
+    };
+
+    mask_and_shift!(group, GROUP_SHIFT, GROUP_MASK)
+        | mask_and_shift!(num, NUM_SHIFT, NUM_MASK)
+        | mask_and_shift!(size, SIZE_SHIFT, SIZE_MASK)
+        | mask_and_shift!(dir, DIR_SHIFT, DIR_MASK)
+}
+
+const NUM_BITS: RawOpcode = 8;
+const GROUP_BITS: RawOpcode = 8;
+
+const NUM_SHIFT: RawOpcode = 0;
+const GROUP_SHIFT: RawOpcode = NUM_SHIFT + NUM_BITS;
+const SIZE_SHIFT: RawOpcode = GROUP_SHIFT + GROUP_BITS;
+const DIR_SHIFT: RawOpcode = SIZE_SHIFT + SIZE_BITS;
+
+const NUM_MASK: RawOpcode = (1 << NUM_BITS) - 1;
+const GROUP_MASK: RawOpcode = (1 << GROUP_BITS) - 1;
+const SIZE_MASK: RawOpcode = (1 << SIZE_BITS) - 1;
+const DIR_MASK: RawOpcode = (1 << DIR_BITS) - 1;
+
+#[cfg(any(
+    target_arch = "x86",
+    target_arch = "arm",
+    target_arch = "s390x",
+    target_arch = "x86_64",
+    target_arch = "aarch64",
+    target_arch = "riscv32",
+    target_arch = "riscv64",
+    target_arch = "loongarch64",
+    target_arch = "csky"
+))]
+mod consts {
+    use super::RawOpcode;
+
+    pub(super) const NONE: RawOpcode = 0;
+    pub(super) const READ: RawOpcode = 2;
+    pub(super) const WRITE: RawOpcode = 1;
+    pub(super) const SIZE_BITS: RawOpcode = 14;
+    pub(super) const DIR_BITS: RawOpcode = 2;
+}
+
+#[cfg(any(
+    target_arch = "mips",
+    target_arch = "mips32r6",
+    target_arch = "mips64",
+    target_arch = "mips64r6",
+    target_arch = "powerpc",
+    target_arch = "powerpc64",
+    target_arch = "sparc",
+    target_arch = "sparc64"
+))]
+mod consts {
+    use super::RawOpcode;
+
+    pub(super) const NONE: RawOpcode = 1;
+    pub(super) const READ: RawOpcode = 2;
+    pub(super) const WRITE: RawOpcode = 4;
+    pub(super) const SIZE_BITS: RawOpcode = 13;
+    pub(super) const DIR_BITS: RawOpcode = 3;
+}
+
+#[cfg(not(any(
+    // These have no ioctl opcodes defined in linux_raw_sys
+    // so can't use that as a known-good value for this test.
+    target_arch = "sparc",
+    target_arch = "sparc64"
+)))]
+#[test]
+fn check_known_opcodes() {
+    use crate::backend::c::{c_long, c_uint};
+    use core::mem::size_of;
+
+    // _IOR('U', 15, unsigned int)
+    assert_eq!(
+        compose_opcode(
+            Direction::Read,
+            b'U' as RawOpcode,
+            15,
+            size_of::<c_uint>() as RawOpcode
+        ),
+        linux_raw_sys::ioctl::USBDEVFS_CLAIMINTERFACE as RawOpcode
+    );
+
+    // _IOW('v', 2, long)
+    assert_eq!(
+        compose_opcode(
+            Direction::Write,
+            b'v' as RawOpcode,
+            2,
+            size_of::<c_long>() as RawOpcode
+        ),
+        linux_raw_sys::ioctl::FS_IOC_SETVERSION as RawOpcode
+    );
+}