Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

5 files changed, 549 insertions, 0 deletions

diff --git a/vendor/rustix/src/mm/madvise.rs b/vendor/rustix/src/mm/madvise.rs
new file mode 100644
index 0000000..4015d12
--- /dev/null
+++ b/vendor/rustix/src/mm/madvise.rs
@@ -0,0 +1,49 @@
+//! The `madvise` function.
+//!
+//! # Safety
+//!
+//! `madvise` operates on a raw pointer. Some forms of `madvise` may
+//! mutate the memory or have other side effects.
+#![allow(unsafe_code)]
+
+use crate::{backend, io};
+use core::ffi::c_void;
+
+pub use backend::mm::types::Advice;
+
+/// `posix_madvise(addr, len, advice)`—Declares an expected access pattern
+/// for a memory-mapped file.
+///
+/// # Safety
+///
+/// `addr` must be a valid pointer to memory that is appropriate to call
+/// `posix_madvise` on. Some forms of `advice` may mutate the memory or evoke a
+/// variety of side-effects on the mapping and/or the file.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux `madvise`]
+///  - [Linux `posix_madvise`]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_madvise.html
+/// [Linux `madvise`]: https://man7.org/linux/man-pages/man2/madvise.2.html
+/// [Linux `posix_madvise`]: https://man7.org/linux/man-pages/man3/posix_madvise.3.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/madvise.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=madvise&sektion=2
+/// [NetBSD]: https://man.netbsd.org/madvise.2
+/// [OpenBSD]: https://man.openbsd.org/madvise.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=madvise&section=2
+/// [illumos]: https://illumos.org/man/3C/madvise
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Memory_002dmapped-I_002fO.html#index-madvise
+#[inline]
+#[doc(alias = "posix_madvise")]
+pub unsafe fn madvise(addr: *mut c_void, len: usize, advice: Advice) -> io::Result<()> {
+    backend::mm::syscalls::madvise(addr, len, advice)
+}
diff --git a/vendor/rustix/src/mm/mmap.rs b/vendor/rustix/src/mm/mmap.rs
new file mode 100644
index 0000000..3f6523f
--- /dev/null
+++ b/vendor/rustix/src/mm/mmap.rs
@@ -0,0 +1,409 @@
+//! The `mmap` API.
+//!
+//! # Safety
+//!
+//! `mmap` and related functions manipulate raw pointers and have special
+//! semantics and are wildly unsafe.
+#![allow(unsafe_code)]
+
+use crate::{backend, io};
+use backend::fd::AsFd;
+use core::ffi::c_void;
+
+#[cfg(any(linux_kernel, freebsdlike, netbsdlike))]
+pub use backend::mm::types::MlockAllFlags;
+#[cfg(linux_kernel)]
+pub use backend::mm::types::MlockFlags;
+#[cfg(any(target_os = "emscripten", target_os = "linux"))]
+pub use backend::mm::types::MremapFlags;
+pub use backend::mm::types::{MapFlags, MprotectFlags, ProtFlags};
+
+impl MapFlags {
+    /// Create `MAP_HUGETLB` with provided size of huge page.
+    ///
+    /// Under the hood it computes
+    /// `MAP_HUGETLB | (huge_page_size_log2 << MAP_HUGE_SHIFT)`.
+    /// `huge_page_size_log2` denotes logarithm of huge page size to use and
+    /// should be between 16 and 63 (inclusive).
+    ///
+    /// ```
+    /// use rustix::mm::MapFlags;
+    ///
+    /// let f = MapFlags::hugetlb_with_size_log2(30).unwrap();
+    /// assert_eq!(f, MapFlags::HUGETLB | MapFlags::HUGE_1GB);
+    /// ```
+    #[cfg(linux_kernel)]
+    pub const fn hugetlb_with_size_log2(huge_page_size_log2: u32) -> Option<Self> {
+        use linux_raw_sys::general::{MAP_HUGETLB, MAP_HUGE_SHIFT};
+        if 16 <= huge_page_size_log2 && huge_page_size_log2 <= 63 {
+            let bits = MAP_HUGETLB | (huge_page_size_log2 << MAP_HUGE_SHIFT);
+            Self::from_bits(bits)
+        } else {
+            None
+        }
+    }
+}
+
+/// `mmap(ptr, len, prot, flags, fd, offset)`—Create a file-backed memory
+/// mapping.
+///
+/// For anonymous mappings (`MAP_ANON`/`MAP_ANONYMOUS`), see
+/// [`mmap_anonymous`].
+///
+/// # Safety
+///
+/// Raw pointers and lots of special semantics.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/mmap.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/mmap.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=mmap&sektion=2
+/// [NetBSD]: https://man.netbsd.org/mmap.2
+/// [OpenBSD]: https://man.openbsd.org/mmap.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=mmap&section=2
+/// [illumos]: https://illumos.org/man/2/mmap
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Memory_002dmapped-I_002fO.html#index-mmap
+#[inline]
+pub unsafe fn mmap<Fd: AsFd>(
+    ptr: *mut c_void,
+    len: usize,
+    prot: ProtFlags,
+    flags: MapFlags,
+    fd: Fd,
+    offset: u64,
+) -> io::Result<*mut c_void> {
+    backend::mm::syscalls::mmap(ptr, len, prot, flags, fd.as_fd(), offset)
+}
+
+/// `mmap(ptr, len, prot, MAP_ANONYMOUS | flags, -1, 0)`—Create an anonymous
+/// memory mapping.
+///
+/// For file-backed mappings, see [`mmap`].
+///
+/// # Safety
+///
+/// Raw pointers and lots of special semantics.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/mmap.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/mmap.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=mmap&sektion=2
+/// [NetBSD]: https://man.netbsd.org/mmap.2
+/// [OpenBSD]: https://man.openbsd.org/mmap.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=mmap&section=2
+/// [illumos]: https://illumos.org/man/2/mmap
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Memory_002dmapped-I_002fO.html#index-mmap
+#[inline]
+#[doc(alias = "mmap")]
+pub unsafe fn mmap_anonymous(
+    ptr: *mut c_void,
+    len: usize,
+    prot: ProtFlags,
+    flags: MapFlags,
+) -> io::Result<*mut c_void> {
+    backend::mm::syscalls::mmap_anonymous(ptr, len, prot, flags)
+}
+
+/// `munmap(ptr, len)`—Remove a memory mapping.
+///
+/// # Safety
+///
+/// Raw pointers and lots of special semantics.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/munmap.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/munmap.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/munmap.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=munmap&sektion=2
+/// [NetBSD]: https://man.netbsd.org/munmap.2
+/// [OpenBSD]: https://man.openbsd.org/munmap.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=munmap&section=2
+/// [illumos]: https://illumos.org/man/2/munmap
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Memory_002dmapped-I_002fO.html#index-munmap
+#[inline]
+pub unsafe fn munmap(ptr: *mut c_void, len: usize) -> io::Result<()> {
+    backend::mm::syscalls::munmap(ptr, len)
+}
+
+/// `mremap(old_address, old_size, new_size, flags)`—Resize, modify, and/or
+/// move a memory mapping.
+///
+/// For moving a mapping to a fixed address (`MREMAP_FIXED`), see
+/// [`mremap_fixed`].
+///
+/// # Safety
+///
+/// Raw pointers and lots of special semantics.
+///
+/// # References
+///  - [Linux]
+///
+/// [Linux]: https://man7.org/linux/man-pages/man2/mremap.2.html
+#[cfg(any(target_os = "emscripten", target_os = "linux"))]
+#[inline]
+pub unsafe fn mremap(
+    old_address: *mut c_void,
+    old_size: usize,
+    new_size: usize,
+    flags: MremapFlags,
+) -> io::Result<*mut c_void> {
+    backend::mm::syscalls::mremap(old_address, old_size, new_size, flags)
+}
+
+/// `mremap(old_address, old_size, new_size, MREMAP_FIXED | flags)`—Resize,
+/// modify, and/or move a memory mapping to a specific address.
+///
+/// For `mremap` without moving to a specific address, see [`mremap`].
+/// [`mremap_fixed`].
+///
+/// # Safety
+///
+/// Raw pointers and lots of special semantics.
+///
+/// # References
+///  - [Linux]
+///
+/// [Linux]: https://man7.org/linux/man-pages/man2/mremap.2.html
+#[cfg(any(target_os = "emscripten", target_os = "linux"))]
+#[inline]
+#[doc(alias = "mremap")]
+pub unsafe fn mremap_fixed(
+    old_address: *mut c_void,
+    old_size: usize,
+    new_size: usize,
+    flags: MremapFlags,
+    new_address: *mut c_void,
+) -> io::Result<*mut c_void> {
+    backend::mm::syscalls::mremap_fixed(old_address, old_size, new_size, flags, new_address)
+}
+
+/// `mprotect(ptr, len, flags)`—Change the protection flags of a region of
+/// memory.
+///
+/// # Safety
+///
+/// Raw pointers and lots of special semantics.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/mprotect.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/mprotect.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/mprotect.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=mprotect&sektion=2
+/// [NetBSD]: https://man.netbsd.org/mprotect.2
+/// [OpenBSD]: https://man.openbsd.org/mprotect.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=mprotect&section=2
+/// [illumos]: https://illumos.org/man/2/mprotect
+#[inline]
+pub unsafe fn mprotect(ptr: *mut c_void, len: usize, flags: MprotectFlags) -> io::Result<()> {
+    backend::mm::syscalls::mprotect(ptr, len, flags)
+}
+
+/// `mlock(ptr, len)`—Lock memory into RAM.
+///
+/// # Safety
+///
+/// This function operates on raw pointers, but it should only be used on
+/// memory which the caller owns. Technically, locking memory shouldn't violate
+/// any invariants, but since unlocking it can violate invariants, this
+/// function is also unsafe for symmetry.
+///
+/// Some implementations implicitly round the memory region out to the nearest
+/// page boundaries, so this function may lock more memory than explicitly
+/// requested if the memory isn't page-aligned. Other implementations fail if
+/// the memory isn't page-aligned.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/mlock.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/mlock.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/mlock.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=mlock&sektion=2
+/// [NetBSD]: https://man.netbsd.org/mlock.2
+/// [OpenBSD]: https://man.openbsd.org/mlock.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=mlock&section=2
+/// [illumos]: https://illumos.org/man/3C/mlock
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Page-Lock-Functions.html#index-mlock
+#[inline]
+pub unsafe fn mlock(ptr: *mut c_void, len: usize) -> io::Result<()> {
+    backend::mm::syscalls::mlock(ptr, len)
+}
+
+/// `mlock2(ptr, len, flags)`—Lock memory into RAM, with flags.
+///
+/// `mlock_with` is the same as [`mlock`] but adds an additional flags operand.
+///
+/// # Safety
+///
+/// This function operates on raw pointers, but it should only be used on
+/// memory which the caller owns. Technically, locking memory shouldn't violate
+/// any invariants, but since unlocking it can violate invariants, this
+/// function is also unsafe for symmetry.
+///
+/// Some implementations implicitly round the memory region out to the nearest
+/// page boundaries, so this function may lock more memory than explicitly
+/// requested if the memory isn't page-aligned.
+///
+/// # References
+///  - [Linux]
+///  - [glibc]
+///
+/// [Linux]: https://man7.org/linux/man-pages/man2/mlock2.2.html
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Page-Lock-Functions.html#index-mlock2
+#[cfg(linux_kernel)]
+#[inline]
+#[doc(alias = "mlock2")]
+pub unsafe fn mlock_with(ptr: *mut c_void, len: usize, flags: MlockFlags) -> io::Result<()> {
+    backend::mm::syscalls::mlock_with(ptr, len, flags)
+}
+
+/// `munlock(ptr, len)`—Unlock memory.
+///
+/// # Safety
+///
+/// This function operates on raw pointers, but it should only be used on
+/// memory which the caller owns, to avoid compromising the `mlock` invariants
+/// of other unrelated code in the process.
+///
+/// Some implementations implicitly round the memory region out to the nearest
+/// page boundaries, so this function may unlock more memory than explicitly
+/// requested if the memory isn't page-aligned.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/munlock.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/munlock.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/munlock.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=munlock&sektion=2
+/// [NetBSD]: https://man.netbsd.org/munlock.2
+/// [OpenBSD]: https://man.openbsd.org/munlock.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=munlock&section=2
+/// [illumos]: https://illumos.org/man/3C/munlock
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Page-Lock-Functions.html#index-munlock
+#[inline]
+pub unsafe fn munlock(ptr: *mut c_void, len: usize) -> io::Result<()> {
+    backend::mm::syscalls::munlock(ptr, len)
+}
+
+/// Locks all pages mapped into the address space of the calling process.
+///
+/// This includes the pages of the code, data, and stack segment, as well as
+/// shared libraries, user space kernel data, shared memory, and memory-mapped
+/// files. All mapped pages are guaranteed to be resident in RAM when the call
+/// returns successfully; the pages are guaranteed to stay in RAM until later
+/// unlocked.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/mlockall.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/mlockall.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=mlockall&sektion=2
+/// [NetBSD]: https://man.netbsd.org/mlockall.2
+/// [OpenBSD]: https://man.openbsd.org/mlockall.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=mlockall&section=2
+/// [illumos]: https://illumos.org/man/3C/mlockall
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Page-Lock-Functions.html#index-mlockall
+#[cfg(any(linux_kernel, freebsdlike, netbsdlike))]
+#[inline]
+pub fn mlockall(flags: MlockAllFlags) -> io::Result<()> {
+    backend::mm::syscalls::mlockall(flags)
+}
+
+/// Unlocks all pages mapped into the address space of the calling process.
+///
+/// # Warnings
+///
+/// This function is aware of all the memory pages in the process, as if it
+/// were a debugger. It unlocks all the pages, which could potentially
+/// compromise security assumptions made by code about memory it has
+/// encapsulated.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/munlockall.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/munlockall.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=munlockall&sektion=2
+/// [NetBSD]: https://man.netbsd.org/munlockall.2
+/// [OpenBSD]: https://man.openbsd.org/munlockall.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=munlockall&section=2
+/// [illumos]: https://illumos.org/man/3C/munlockall
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Page-Lock-Functions.html#index-munlockall
+#[cfg(any(linux_kernel, freebsdlike, netbsdlike))]
+#[inline]
+pub fn munlockall() -> io::Result<()> {
+    backend::mm::syscalls::munlockall()
+}
diff --git a/vendor/rustix/src/mm/mod.rs b/vendor/rustix/src/mm/mod.rs
new file mode 100644
index 0000000..7505cac
--- /dev/null
+++ b/vendor/rustix/src/mm/mod.rs
@@ -0,0 +1,15 @@
+//! Memory map operations.
+
+#[cfg(not(target_os = "redox"))]
+mod madvise;
+mod mmap;
+mod msync;
+#[cfg(linux_kernel)]
+mod userfaultfd;
+
+#[cfg(not(target_os = "redox"))]
+pub use madvise::{madvise, Advice};
+pub use mmap::*;
+pub use msync::{msync, MsyncFlags};
+#[cfg(linux_kernel)]
+pub use userfaultfd::{userfaultfd, UserfaultfdFlags};
diff --git a/vendor/rustix/src/mm/msync.rs b/vendor/rustix/src/mm/msync.rs
new file mode 100644
index 0000000..c61d7c3
--- /dev/null
+++ b/vendor/rustix/src/mm/msync.rs
@@ -0,0 +1,46 @@
+//! The `msync` function.
+//!
+//! # Safety
+//!
+//! `msync` operates on a raw pointer. Some forms of `msync` may mutate the
+//! memory or have other side effects.
+#![allow(unsafe_code)]
+
+use crate::{backend, io};
+use core::ffi::c_void;
+
+pub use backend::mm::types::MsyncFlags;
+
+/// `msync(addr, len, flags)`—Synchronizes a memory-mapping with its backing
+/// storage.
+///
+/// # Safety
+///
+/// `addr` must be a valid pointer to memory that is appropriate to call
+/// `msync` on. Some forms of `msync` may mutate the memory or evoke a variety
+/// of side-effects on the mapping and/or the file.
+///
+/// # References
+///  - [POSIX]
+///  - [Linux]
+///  - [Apple]
+///  - [FreeBSD]
+///  - [NetBSD]
+///  - [OpenBSD]
+///  - [DragonFly BSD]
+///  - [illumos]
+///  - [glibc]
+///
+/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/msync.html
+/// [Linux]: https://man7.org/linux/man-pages/man2/msync.2.html
+/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/msync.2.html
+/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=msync&sektion=2
+/// [NetBSD]: https://man.netbsd.org/msync.2
+/// [OpenBSD]: https://man.openbsd.org/msync.2
+/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=msync&section=2
+/// [illumos]: https://illumos.org/man/3C/msync
+/// [glibc]: https://www.gnu.org/software/libc/manual/html_node/Memory_002dmapped-I_002fO.html#index-msync
+#[inline]
+pub unsafe fn msync(addr: *mut c_void, len: usize, flags: MsyncFlags) -> io::Result<()> {
+    backend::mm::syscalls::msync(addr, len, flags)
+}
diff --git a/vendor/rustix/src/mm/userfaultfd.rs b/vendor/rustix/src/mm/userfaultfd.rs
new file mode 100644
index 0000000..201d547
--- /dev/null
+++ b/vendor/rustix/src/mm/userfaultfd.rs
@@ -0,0 +1,30 @@
+//! The Linux `userfaultfd` API.
+//!
+//! # Safety
+//!
+//! Calling `userfaultfd` is safe, but the returned file descriptor lets users
+//! observe and manipulate process memory in magical ways.
+#![allow(unsafe_code)]
+
+use crate::fd::OwnedFd;
+use crate::{backend, io};
+
+pub use backend::mm::types::UserfaultfdFlags;
+
+/// `userfaultfd(flags)`
+///
+/// # Safety
+///
+/// The call itself is safe, but the returned file descriptor lets users
+/// observe and manipulate process memory in magical ways.
+///
+/// # References
+///  - [Linux]
+///  - [Linux userfaultfd]
+///
+/// [Linux]: https://man7.org/linux/man-pages/man2/userfaultfd.2.html
+/// [Linux userfaultfd]: https://www.kernel.org/doc/Documentation/vm/userfaultfd.txt
+#[inline]
+pub unsafe fn userfaultfd(flags: UserfaultfdFlags) -> io::Result<OwnedFd> {
+    backend::mm::syscalls::userfaultfd(flags)
+}