chore: add vendor directory

1 files changed, 780 insertions, 0 deletions

diff --git a/vendor/rustix/src/backend/libc/thread/syscalls.rs b/vendor/rustix/src/backend/libc/thread/syscalls.rs
new file mode 100644
index 00000000..9198a7fb
--- /dev/null
+++ b/vendor/rustix/src/backend/libc/thread/syscalls.rs
@@ -0,0 +1,780 @@
+//! libc syscalls supporting `rustix::thread`.
+
+#[cfg(any(freebsdlike, linux_kernel, target_os = "fuchsia"))]
+use super::types::RawCpuSet;
+use crate::backend::c;
+use crate::backend::conv::ret;
+use crate::io;
+#[cfg(any(freebsdlike, linux_kernel, target_os = "fuchsia"))]
+use crate::pid::Pid;
+#[cfg(not(any(
+    apple,
+    freebsdlike,
+    target_os = "emscripten",
+    target_os = "espidf",
+    target_os = "haiku",
+    target_os = "openbsd",
+    target_os = "redox",
+    target_os = "vita",
+    target_os = "wasi",
+)))]
+use crate::thread::ClockId;
+#[cfg(linux_kernel)]
+use crate::thread::{Cpuid, MembarrierCommand, MembarrierQuery};
+#[cfg(not(target_os = "redox"))]
+use crate::thread::{NanosleepRelativeResult, Timespec};
+#[cfg(all(target_env = "gnu", fix_y2038))]
+use crate::timespec::LibcTimespec;
+#[cfg(not(fix_y2038))]
+use crate::timespec::{as_libc_timespec_mut_ptr, as_libc_timespec_ptr};
+#[cfg(linux_kernel)]
+use crate::utils::option_as_ptr;
+use core::mem::MaybeUninit;
+#[cfg(linux_kernel)]
+use core::sync::atomic::AtomicU32;
+#[cfg(linux_kernel)]
+use {
+    crate::backend::conv::{borrowed_fd, ret_c_int, ret_u32, ret_usize},
+    crate::fd::BorrowedFd,
+    crate::thread::futex,
+    crate::utils::as_mut_ptr,
+};
+
+#[cfg(all(target_env = "gnu", fix_y2038))]
+weak!(fn __clock_nanosleep_time64(c::clockid_t, c::c_int, *const LibcTimespec, *mut LibcTimespec) -> c::c_int);
+#[cfg(all(target_env = "gnu", fix_y2038))]
+weak!(fn __nanosleep64(*const LibcTimespec, *mut LibcTimespec) -> c::c_int);
+
+#[cfg(not(any(
+    apple,
+    target_os = "dragonfly",
+    target_os = "emscripten",
+    target_os = "espidf",
+    target_os = "freebsd", // FreeBSD 12 has clock_nanosleep, but libc targets FreeBSD 11.
+    target_os = "haiku",
+    target_os = "horizon",
+    target_os = "openbsd",
+    target_os = "redox",
+    target_os = "vita",
+    target_os = "wasi",
+)))]
+#[inline]
+pub(crate) fn clock_nanosleep_relative(id: ClockId, request: &Timespec) -> NanosleepRelativeResult {
+    // Old 32-bit version: libc has `clock_nanosleep` but it is not y2038 safe
+    // by default. But there may be a `__clock_nanosleep_time64` we can use.
+    #[cfg(fix_y2038)]
+    {
+        #[cfg(target_env = "gnu")]
+        if let Some(libc_clock_nanosleep) = __clock_nanosleep_time64.get() {
+            let flags = 0;
+            let mut remain = MaybeUninit::<LibcTimespec>::uninit();
+
+            unsafe {
+                return match libc_clock_nanosleep(
+                    id as c::clockid_t,
+                    flags,
+                    &request.clone().into(),
+                    remain.as_mut_ptr(),
+                ) {
+                    0 => NanosleepRelativeResult::Ok,
+                    err if err == io::Errno::INTR.0 => {
+                        NanosleepRelativeResult::Interrupted(remain.assume_init().into())
+                    }
+                    err => NanosleepRelativeResult::Err(io::Errno(err)),
+                };
+            }
+        }
+
+        clock_nanosleep_relative_old(id, request)
+    }
+
+    // Main version: libc is y2038 safe and has `clock_nanosleep`.
+    #[cfg(not(fix_y2038))]
+    unsafe {
+        let flags = 0;
+        let mut remain = MaybeUninit::<Timespec>::uninit();
+
+        match c::clock_nanosleep(
+            id as c::clockid_t,
+            flags,
+            as_libc_timespec_ptr(request),
+            as_libc_timespec_mut_ptr(&mut remain),
+        ) {
+            0 => NanosleepRelativeResult::Ok,
+            err if err == io::Errno::INTR.0 => {
+                NanosleepRelativeResult::Interrupted(remain.assume_init())
+            }
+            err => NanosleepRelativeResult::Err(io::Errno(err)),
+        }
+    }
+}
+
+#[cfg(all(
+    fix_y2038,
+    not(any(
+        apple,
+        target_os = "emscripten",
+        target_os = "haiku",
+        target_os = "horizon",
+        target_os = "vita"
+    ))
+))]
+fn clock_nanosleep_relative_old(
+    id: crate::clockid::ClockId,
+    request: &Timespec,
+) -> NanosleepRelativeResult {
+    let tv_sec = match request.tv_sec.try_into() {
+        Ok(tv_sec) => tv_sec,
+        Err(_) => return NanosleepRelativeResult::Err(io::Errno::OVERFLOW),
+    };
+    let tv_nsec = match request.tv_nsec.try_into() {
+        Ok(tv_nsec) => tv_nsec,
+        Err(_) => return NanosleepRelativeResult::Err(io::Errno::INVAL),
+    };
+    let old_request = c::timespec { tv_sec, tv_nsec };
+    let mut old_remain = MaybeUninit::<c::timespec>::uninit();
+    let flags = 0;
+
+    unsafe {
+        match c::clock_nanosleep(
+            id as c::clockid_t,
+            flags,
+            &old_request,
+            old_remain.as_mut_ptr(),
+        ) {
+            0 => NanosleepRelativeResult::Ok,
+            err if err == io::Errno::INTR.0 => {
+                let old_remain = old_remain.assume_init();
+                let remain = Timespec {
+                    tv_sec: old_remain.tv_sec.into(),
+                    tv_nsec: old_remain.tv_nsec.into(),
+                };
+                NanosleepRelativeResult::Interrupted(remain)
+            }
+            err => NanosleepRelativeResult::Err(io::Errno(err)),
+        }
+    }
+}
+
+#[cfg(not(any(
+    apple,
+    target_os = "dragonfly",
+    target_os = "emscripten",
+    target_os = "espidf",
+    target_os = "freebsd", // FreeBSD 12 has clock_nanosleep, but libc targets FreeBSD 11.
+    target_os = "haiku",
+    target_os = "horizon",
+    target_os = "openbsd",
+    target_os = "redox",
+    target_os = "vita",
+    target_os = "wasi",
+)))]
+#[inline]
+pub(crate) fn clock_nanosleep_absolute(id: ClockId, request: &Timespec) -> io::Result<()> {
+    // Old 32-bit version: libc has `clock_nanosleep` but it is not y2038 safe
+    // by default. But there may be a `__clock_nanosleep_time64` we can use.
+    #[cfg(fix_y2038)]
+    {
+        #[cfg(target_env = "gnu")]
+        if let Some(libc_clock_nanosleep) = __clock_nanosleep_time64.get() {
+            let flags = c::TIMER_ABSTIME;
+            unsafe {
+                return match libc_clock_nanosleep(
+                    id as c::clockid_t,
+                    flags,
+                    &request.clone().into(),
+                    core::ptr::null_mut(),
+                ) {
+                    0 => Ok(()),
+                    err => Err(io::Errno(err)),
+                };
+            }
+        }
+
+        clock_nanosleep_absolute_old(id, request)
+    }
+
+    // Main version: libc is y2038 safe and has `clock_nanosleep`.
+    #[cfg(not(fix_y2038))]
+    {
+        let flags = c::TIMER_ABSTIME;
+
+        match unsafe {
+            c::clock_nanosleep(
+                id as c::clockid_t,
+                flags as _,
+                as_libc_timespec_ptr(request),
+                core::ptr::null_mut(),
+            )
+        } {
+            0 => Ok(()),
+            err => Err(io::Errno(err)),
+        }
+    }
+}
+
+#[cfg(all(
+    fix_y2038,
+    not(any(
+        apple,
+        target_os = "emscripten",
+        target_os = "haiku",
+        target_os = "horizon",
+        target_os = "vita"
+    ))
+))]
+fn clock_nanosleep_absolute_old(id: crate::clockid::ClockId, request: &Timespec) -> io::Result<()> {
+    let flags = c::TIMER_ABSTIME;
+
+    let old_request = c::timespec {
+        tv_sec: request.tv_sec.try_into().map_err(|_| io::Errno::OVERFLOW)?,
+        tv_nsec: request.tv_nsec.try_into().map_err(|_| io::Errno::INVAL)?,
+    };
+    match unsafe {
+        c::clock_nanosleep(
+            id as c::clockid_t,
+            flags,
+            &old_request,
+            core::ptr::null_mut(),
+        )
+    } {
+        0 => Ok(()),
+        err => Err(io::Errno(err)),
+    }
+}
+
+#[cfg(not(target_os = "redox"))]
+#[inline]
+pub(crate) fn nanosleep(request: &Timespec) -> NanosleepRelativeResult {
+    // Old 32-bit version: libc has `nanosleep` but it is not y2038 safe by
+    // default. But there may be a `__nanosleep64` we can use.
+    #[cfg(fix_y2038)]
+    {
+        #[cfg(target_env = "gnu")]
+        if let Some(libc_nanosleep) = __nanosleep64.get() {
+            let mut remain = MaybeUninit::<LibcTimespec>::uninit();
+            unsafe {
+                return match ret(libc_nanosleep(&request.clone().into(), remain.as_mut_ptr())) {
+                    Ok(()) => NanosleepRelativeResult::Ok,
+                    Err(io::Errno::INTR) => {
+                        NanosleepRelativeResult::Interrupted(remain.assume_init().into())
+                    }
+                    Err(err) => NanosleepRelativeResult::Err(err),
+                };
+            }
+        }
+
+        nanosleep_old(request)
+    }
+
+    // Main version: libc is y2038 safe and has `nanosleep`.
+    #[cfg(not(fix_y2038))]
+    unsafe {
+        let mut remain = MaybeUninit::<Timespec>::uninit();
+
+        match ret(c::nanosleep(
+            as_libc_timespec_ptr(request),
+            as_libc_timespec_mut_ptr(&mut remain),
+        )) {
+            Ok(()) => NanosleepRelativeResult::Ok,
+            Err(io::Errno::INTR) => NanosleepRelativeResult::Interrupted(remain.assume_init()),
+            Err(err) => NanosleepRelativeResult::Err(err),
+        }
+    }
+}
+
+#[cfg(fix_y2038)]
+fn nanosleep_old(request: &Timespec) -> NanosleepRelativeResult {
+    let tv_sec = match request.tv_sec.try_into() {
+        Ok(tv_sec) => tv_sec,
+        Err(_) => return NanosleepRelativeResult::Err(io::Errno::OVERFLOW),
+    };
+    let tv_nsec = match request.tv_nsec.try_into() {
+        Ok(tv_nsec) => tv_nsec,
+        Err(_) => return NanosleepRelativeResult::Err(io::Errno::INVAL),
+    };
+    let old_request = c::timespec { tv_sec, tv_nsec };
+    let mut old_remain = MaybeUninit::<c::timespec>::uninit();
+
+    unsafe {
+        match ret(c::nanosleep(&old_request, old_remain.as_mut_ptr())) {
+            Ok(()) => NanosleepRelativeResult::Ok,
+            Err(io::Errno::INTR) => {
+                let old_remain = old_remain.assume_init();
+                let remain = Timespec {
+                    tv_sec: old_remain.tv_sec.into(),
+                    tv_nsec: old_remain.tv_nsec.into(),
+                };
+                NanosleepRelativeResult::Interrupted(remain)
+            }
+            Err(err) => NanosleepRelativeResult::Err(err),
+        }
+    }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+#[must_use]
+pub(crate) fn gettid() -> Pid {
+    // `gettid` wasn't supported in glibc until 2.30, and musl until 1.2.2,
+    // so use `syscall`.
+    // <https://sourceware.org/bugzilla/show_bug.cgi?id=6399#c62>
+    weak_or_syscall! {
+        fn gettid() via SYS_gettid -> c::pid_t
+    }
+
+    unsafe {
+        let tid = gettid();
+        Pid::from_raw_unchecked(tid)
+    }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setns(fd: BorrowedFd<'_>, nstype: c::c_int) -> io::Result<c::c_int> {
+    // `setns` wasn't supported in glibc until 2.14, and musl until 0.9.5,
+    // so use `syscall`.
+    weak_or_syscall! {
+        fn setns(fd: c::c_int, nstype: c::c_int) via SYS_setns -> c::c_int
+    }
+
+    unsafe { ret_c_int(setns(borrowed_fd(fd), nstype)) }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn unshare(flags: crate::thread::UnshareFlags) -> io::Result<()> {
+    unsafe { ret(c::unshare(flags.bits() as i32)) }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn capget(
+    header: &mut linux_raw_sys::general::__user_cap_header_struct,
+    data: &mut [MaybeUninit<linux_raw_sys::general::__user_cap_data_struct>],
+) -> io::Result<()> {
+    syscall! {
+        fn capget(
+            hdrp: *mut linux_raw_sys::general::__user_cap_header_struct,
+            data: *mut linux_raw_sys::general::__user_cap_data_struct
+        ) via SYS_capget -> c::c_int
+    }
+
+    unsafe {
+        ret(capget(
+            as_mut_ptr(header),
+            data.as_mut_ptr()
+                .cast::<linux_raw_sys::general::__user_cap_data_struct>(),
+        ))
+    }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn capset(
+    header: &mut linux_raw_sys::general::__user_cap_header_struct,
+    data: &[linux_raw_sys::general::__user_cap_data_struct],
+) -> io::Result<()> {
+    syscall! {
+        fn capset(
+            hdrp: *mut linux_raw_sys::general::__user_cap_header_struct,
+            data: *const linux_raw_sys::general::__user_cap_data_struct
+        ) via SYS_capset -> c::c_int
+    }
+
+    unsafe { ret(capset(as_mut_ptr(header), data.as_ptr())) }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setuid_thread(uid: crate::ugid::Uid) -> io::Result<()> {
+    syscall! {
+        fn setuid(uid: c::uid_t) via SYS_setuid -> c::c_int
+    }
+
+    unsafe { ret(setuid(uid.as_raw())) }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setresuid_thread(
+    ruid: crate::ugid::Uid,
+    euid: crate::ugid::Uid,
+    suid: crate::ugid::Uid,
+) -> io::Result<()> {
+    #[cfg(any(target_arch = "x86", target_arch = "arm", target_arch = "sparc"))]
+    const SYS: c::c_long = c::SYS_setresuid32 as c::c_long;
+    #[cfg(not(any(target_arch = "x86", target_arch = "arm", target_arch = "sparc")))]
+    const SYS: c::c_long = c::SYS_setresuid as c::c_long;
+
+    syscall! {
+        fn setresuid(ruid: c::uid_t, euid: c::uid_t, suid: c::uid_t) via SYS -> c::c_int
+    }
+
+    unsafe { ret(setresuid(ruid.as_raw(), euid.as_raw(), suid.as_raw())) }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setgid_thread(gid: crate::ugid::Gid) -> io::Result<()> {
+    syscall! {
+        fn setgid(gid: c::gid_t) via SYS_setgid -> c::c_int
+    }
+
+    unsafe { ret(setgid(gid.as_raw())) }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setresgid_thread(
+    rgid: crate::ugid::Gid,
+    egid: crate::ugid::Gid,
+    sgid: crate::ugid::Gid,
+) -> io::Result<()> {
+    #[cfg(any(target_arch = "x86", target_arch = "arm", target_arch = "sparc"))]
+    const SYS: c::c_long = c::SYS_setresgid32 as c::c_long;
+    #[cfg(not(any(target_arch = "x86", target_arch = "arm", target_arch = "sparc")))]
+    const SYS: c::c_long = c::SYS_setresgid as c::c_long;
+
+    syscall! {
+        fn setresgid(rgid: c::gid_t, egid: c::gid_t, sgid: c::gid_t) via SYS -> c::c_int
+    }
+
+    unsafe { ret(setresgid(rgid.as_raw(), egid.as_raw(), sgid.as_raw())) }
+}
+
+/// # Safety
+///
+/// The raw pointers must point to valid aligned memory.
+#[cfg(linux_kernel)]
+pub(crate) unsafe fn futex_val2(
+    uaddr: *const AtomicU32,
+    op: super::futex::Operation,
+    flags: futex::Flags,
+    val: u32,
+    val2: u32,
+    uaddr2: *const AtomicU32,
+    val3: u32,
+) -> io::Result<usize> {
+    // Pass `val2` in the least-significant bytes of the `timeout` argument.
+    // [“the kernel casts the timeout value first to unsigned long, then to
+    // uint32_t”], so we perform that exact conversion in reverse to create
+    // the pointer.
+    //
+    // [“the kernel casts the timeout value first to unsigned long, then to uint32_t”]: https://man7.org/linux/man-pages/man2/futex.2.html
+    let timeout = val2 as usize as *const Timespec;
+
+    #[cfg(all(
+        target_pointer_width = "32",
+        not(any(target_arch = "aarch64", target_arch = "x86_64"))
+    ))]
+    {
+        // TODO: Upstream this to the libc crate.
+        #[allow(non_upper_case_globals)]
+        const SYS_futex_time64: i32 = linux_raw_sys::general::__NR_futex_time64 as i32;
+
+        syscall! {
+            fn futex_time64(
+                uaddr: *const AtomicU32,
+                futex_op: c::c_int,
+                val: u32,
+                timeout: *const Timespec,
+                uaddr2: *const AtomicU32,
+                val3: u32
+            ) via SYS_futex_time64 -> c::ssize_t
+        }
+
+        ret_usize(futex_time64(
+            uaddr,
+            op as i32 | flags.bits() as i32,
+            val,
+            timeout,
+            uaddr2,
+            val3,
+        ))
+    }
+
+    #[cfg(any(
+        target_pointer_width = "64",
+        target_arch = "aarch64",
+        target_arch = "x86_64"
+    ))]
+    {
+        syscall! {
+            fn futex(
+                uaddr: *const AtomicU32,
+                futex_op: c::c_int,
+                val: u32,
+                timeout: *const Timespec,
+                uaddr2: *const AtomicU32,
+                val3: u32
+            ) via SYS_futex -> c::c_long
+        }
+
+        ret_usize(futex(
+            uaddr,
+            op as i32 | flags.bits() as i32,
+            val,
+            timeout.cast(),
+            uaddr2,
+            val3,
+        ) as isize)
+    }
+}
+
+/// # Safety
+///
+/// The raw pointers must point to valid aligned memory.
+#[cfg(linux_kernel)]
+pub(crate) unsafe fn futex_timeout(
+    uaddr: *const AtomicU32,
+    op: super::futex::Operation,
+    flags: futex::Flags,
+    val: u32,
+    timeout: Option<&Timespec>,
+    uaddr2: *const AtomicU32,
+    val3: u32,
+) -> io::Result<usize> {
+    #[cfg(all(
+        target_pointer_width = "32",
+        not(any(target_arch = "aarch64", target_arch = "x86_64"))
+    ))]
+    {
+        // TODO: Upstream this to the libc crate.
+        #[allow(non_upper_case_globals)]
+        const SYS_futex_time64: i32 = linux_raw_sys::general::__NR_futex_time64 as i32;
+
+        syscall! {
+            fn futex_time64(
+                uaddr: *const AtomicU32,
+                futex_op: c::c_int,
+                val: u32,
+                timeout: *const Timespec,
+                uaddr2: *const AtomicU32,
+                val3: u32
+            ) via SYS_futex_time64 -> c::ssize_t
+        }
+
+        ret_usize(futex_time64(
+            uaddr,
+            op as i32 | flags.bits() as i32,
+            val,
+            option_as_ptr(timeout),
+            uaddr2,
+            val3,
+        ))
+        .or_else(|err| {
+            // See the comments in `clock_gettime_via_syscall` about emulation.
+            if err == io::Errno::NOSYS {
+                futex_old_timespec(uaddr, op, flags, val, timeout, uaddr2, val3)
+            } else {
+                Err(err)
+            }
+        })
+    }
+
+    #[cfg(any(
+        target_pointer_width = "64",
+        target_arch = "aarch64",
+        target_arch = "x86_64"
+    ))]
+    {
+        syscall! {
+            fn futex(
+                uaddr: *const AtomicU32,
+                futex_op: c::c_int,
+                val: u32,
+                timeout: *const Timespec,
+                uaddr2: *const AtomicU32,
+                val3: u32
+            ) via SYS_futex -> c::c_long
+        }
+
+        ret_usize(futex(
+            uaddr,
+            op as i32 | flags.bits() as i32,
+            val,
+            option_as_ptr(timeout).cast(),
+            uaddr2,
+            val3,
+        ) as isize)
+    }
+}
+
+/// # Safety
+///
+/// The raw pointers must point to valid aligned memory.
+#[cfg(linux_kernel)]
+#[cfg(all(
+    target_pointer_width = "32",
+    not(any(target_arch = "aarch64", target_arch = "x86_64"))
+))]
+unsafe fn futex_old_timespec(
+    uaddr: *const AtomicU32,
+    op: super::futex::Operation,
+    flags: futex::Flags,
+    val: u32,
+    timeout: Option<&Timespec>,
+    uaddr2: *const AtomicU32,
+    val3: u32,
+) -> io::Result<usize> {
+    syscall! {
+        fn futex(
+            uaddr: *const AtomicU32,
+            futex_op: c::c_int,
+            val: u32,
+            timeout: *const linux_raw_sys::general::__kernel_old_timespec,
+            uaddr2: *const AtomicU32,
+            val3: u32
+        ) via SYS_futex -> c::c_long
+    }
+
+    let old_timeout = if let Some(timeout) = timeout {
+        Some(linux_raw_sys::general::__kernel_old_timespec {
+            tv_sec: timeout.tv_sec.try_into().map_err(|_| io::Errno::INVAL)?,
+            tv_nsec: timeout.tv_nsec.try_into().map_err(|_| io::Errno::INVAL)?,
+        })
+    } else {
+        None
+    };
+    ret_usize(futex(
+        uaddr,
+        op as i32 | flags.bits() as i32,
+        val,
+        option_as_ptr(old_timeout.as_ref()),
+        uaddr2,
+        val3,
+    ) as isize)
+}
+
+#[cfg(linux_kernel)]
+pub(crate) fn futex_waitv(
+    waiters: &[futex::Wait],
+    flags: futex::WaitvFlags,
+    timeout: Option<&Timespec>,
+    clockid: ClockId,
+) -> io::Result<usize> {
+    use futex::Wait as FutexWait;
+    use linux_raw_sys::general::__kernel_clockid_t as clockid_t;
+    syscall! {
+        fn futex_waitv(
+            waiters: *const FutexWait,
+            nr_futexes: c::c_uint,
+            flags: c::c_uint,
+            timeout: *const Timespec,
+            clockid: clockid_t
+        ) via SYS_futex_waitv -> c::c_int
+    }
+
+    let nr_futexes: c::c_uint = waiters.len().try_into().map_err(|_| io::Errno::INVAL)?;
+
+    unsafe {
+        ret_c_int(futex_waitv(
+            waiters.as_ptr(),
+            nr_futexes,
+            flags.bits(),
+            option_as_ptr(timeout).cast(),
+            clockid as _,
+        ))
+        .map(|n| n as usize)
+    }
+}
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setgroups_thread(groups: &[crate::ugid::Gid]) -> io::Result<()> {
+    syscall! {
+        fn setgroups(size: c::size_t, list: *const c::gid_t) via SYS_setgroups -> c::c_int
+    }
+    ret(unsafe { setgroups(groups.len(), groups.as_ptr().cast()) })
+}
+
+#[cfg(any(linux_kernel, target_os = "dragonfly"))]
+#[inline]
+pub(crate) fn sched_getcpu() -> usize {
+    let r = unsafe { c::sched_getcpu() };
+    debug_assert!(r >= 0);
+    r as usize
+}
+
+#[cfg(any(freebsdlike, linux_kernel, target_os = "fuchsia"))]
+#[inline]
+pub(crate) fn sched_getaffinity(pid: Option<Pid>, cpuset: &mut RawCpuSet) -> io::Result<()> {
+    unsafe {
+        ret(c::sched_getaffinity(
+            Pid::as_raw(pid) as _,
+            core::mem::size_of::<RawCpuSet>(),
+            cpuset,
+        ))
+    }
+}
+
+#[cfg(any(freebsdlike, linux_kernel, target_os = "fuchsia"))]
+#[inline]
+pub(crate) fn sched_setaffinity(pid: Option<Pid>, cpuset: &RawCpuSet) -> io::Result<()> {
+    unsafe {
+        ret(c::sched_setaffinity(
+            Pid::as_raw(pid) as _,
+            core::mem::size_of::<RawCpuSet>(),
+            cpuset,
+        ))
+    }
+}
+
+#[inline]
+pub(crate) fn sched_yield() {
+    unsafe {
+        let _ = c::sched_yield();
+    }
+}
+
+// The `membarrier` syscall has a third argument, but it's only used when
+// the `flags` argument is `MEMBARRIER_CMD_FLAG_CPU`.
+#[cfg(linux_kernel)]
+syscall! {
+    fn membarrier_all(
+        cmd: c::c_int,
+        flags: c::c_uint
+    ) via SYS_membarrier -> c::c_int
+}
+
+#[cfg(linux_kernel)]
+pub(crate) fn membarrier_query() -> MembarrierQuery {
+    // glibc does not have a wrapper for `membarrier`; [the documentation]
+    // says to use `syscall`.
+    //
+    // [the documentation]: https://man7.org/linux/man-pages/man2/membarrier.2.html#NOTES
+    const MEMBARRIER_CMD_QUERY: u32 = 0;
+    unsafe {
+        match ret_u32(membarrier_all(MEMBARRIER_CMD_QUERY as i32, 0)) {
+            Ok(query) => MembarrierQuery::from_bits_retain(query),
+            Err(_) => MembarrierQuery::empty(),
+        }
+    }
+}
+
+#[cfg(linux_kernel)]
+pub(crate) fn membarrier(cmd: MembarrierCommand) -> io::Result<()> {
+    unsafe { ret(membarrier_all(cmd as i32, 0)) }
+}
+
+#[cfg(linux_kernel)]
+pub(crate) fn membarrier_cpu(cmd: MembarrierCommand, cpu: Cpuid) -> io::Result<()> {
+    const MEMBARRIER_CMD_FLAG_CPU: u32 = 1;
+
+    syscall! {
+        fn membarrier_cpu(
+            cmd: c::c_int,
+            flags: c::c_uint,
+            cpu_id: c::c_int
+        ) via SYS_membarrier -> c::c_int
+    }
+
+    unsafe {
+        ret(membarrier_cpu(
+            cmd as i32,
+            MEMBARRIER_CMD_FLAG_CPU,
+            bitcast!(cpu.as_raw()),
+        ))
+    }
+}