1 files changed, 291 insertions, 0 deletions
diff --git a/third_party/rust/nix/src/sys/uio.rs b/third_party/rust/nix/src/sys/uio.rs
new file mode 100644
index 0000000000..b31c3068a7
--- /dev/null
+++ b/third_party/rust/nix/src/sys/uio.rs
@@ -0,0 +1,291 @@
+//! Vectored I/O
+
+use crate::errno::Errno;
+use crate::Result;
+use libc::{self, c_int, c_void, off_t, size_t};
+use std::io::{IoSlice, IoSliceMut};
+use std::marker::PhantomData;
+use std::os::unix::io::RawFd;
+
+/// Low-level vectored write to a raw file descriptor
+///
+/// See also [writev(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/writev.html)
+pub fn writev(fd: RawFd, iov: &[IoSlice<'_>]) -> Result<usize> {
+    // SAFETY: to quote the documentation for `IoSlice`:
+    //
+    // [IoSlice] is semantically a wrapper around a &[u8], but is
+    // guaranteed to be ABI compatible with the iovec type on Unix
+    // platforms.
+    //
+    // Because it is ABI compatible, a pointer cast here is valid
+    let res = unsafe {
+        libc::writev(fd, iov.as_ptr() as *const libc::iovec, iov.len() as c_int)
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Low-level vectored read from a raw file descriptor
+///
+/// See also [readv(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/readv.html)
+pub fn readv(fd: RawFd, iov: &mut [IoSliceMut<'_>]) -> Result<usize> {
+    // SAFETY: same as in writev(), IoSliceMut is ABI-compatible with iovec
+    let res = unsafe {
+        libc::readv(fd, iov.as_ptr() as *const libc::iovec, iov.len() as c_int)
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Write to `fd` at `offset` from buffers in `iov`.
+///
+/// Buffers in `iov` will be written in order until all buffers have been written
+/// or an error occurs. The file offset is not changed.
+///
+/// See also: [`writev`](fn.writev.html) and [`pwrite`](fn.pwrite.html)
+#[cfg(not(any(target_os = "redox", target_os = "haiku")))]
+#[cfg_attr(docsrs, doc(cfg(all())))]
+pub fn pwritev(fd: RawFd, iov: &[IoSlice<'_>], offset: off_t) -> Result<usize> {
+    #[cfg(target_env = "uclibc")]
+    let offset = offset as libc::off64_t; // uclibc doesn't use off_t
+
+    // SAFETY: same as in writev()
+    let res = unsafe {
+        libc::pwritev(
+            fd,
+            iov.as_ptr() as *const libc::iovec,
+            iov.len() as c_int,
+            offset,
+        )
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Read from `fd` at `offset` filling buffers in `iov`.
+///
+/// Buffers in `iov` will be filled in order until all buffers have been filled,
+/// no more bytes are available, or an error occurs. The file offset is not
+/// changed.
+///
+/// See also: [`readv`](fn.readv.html) and [`pread`](fn.pread.html)
+#[cfg(not(any(target_os = "redox", target_os = "haiku")))]
+#[cfg_attr(docsrs, doc(cfg(all())))]
+pub fn preadv(
+    fd: RawFd,
+    iov: &mut [IoSliceMut<'_>],
+    offset: off_t,
+) -> Result<usize> {
+    #[cfg(target_env = "uclibc")]
+    let offset = offset as libc::off64_t; // uclibc doesn't use off_t
+
+    // SAFETY: same as in readv()
+    let res = unsafe {
+        libc::preadv(
+            fd,
+            iov.as_ptr() as *const libc::iovec,
+            iov.len() as c_int,
+            offset,
+        )
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Low-level write to a file, with specified offset.
+///
+/// See also [pwrite(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/pwrite.html)
+// TODO: move to unistd
+pub fn pwrite(fd: RawFd, buf: &[u8], offset: off_t) -> Result<usize> {
+    let res = unsafe {
+        libc::pwrite(
+            fd,
+            buf.as_ptr() as *const c_void,
+            buf.len() as size_t,
+            offset,
+        )
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Low-level read from a file, with specified offset.
+///
+/// See also [pread(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/pread.html)
+// TODO: move to unistd
+pub fn pread(fd: RawFd, buf: &mut [u8], offset: off_t) -> Result<usize> {
+    let res = unsafe {
+        libc::pread(
+            fd,
+            buf.as_mut_ptr() as *mut c_void,
+            buf.len() as size_t,
+            offset,
+        )
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// A slice of memory in a remote process, starting at address `base`
+/// and consisting of `len` bytes.
+///
+/// This is the same underlying C structure as `IoSlice`,
+/// except that it refers to memory in some other process, and is
+/// therefore not represented in Rust by an actual slice as `IoSlice` is. It
+/// is used with [`process_vm_readv`](fn.process_vm_readv.html)
+/// and [`process_vm_writev`](fn.process_vm_writev.html).
+#[cfg(any(target_os = "linux", target_os = "android"))]
+#[cfg_attr(docsrs, doc(cfg(all())))]
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct RemoteIoVec {
+    /// The starting address of this slice (`iov_base`).
+    pub base: usize,
+    /// The number of bytes in this slice (`iov_len`).
+    pub len: usize,
+}
+
+/// A vector of buffers.
+///
+/// Vectored I/O methods like [`writev`] and [`readv`] use this structure for
+/// both reading and writing.  Each `IoVec` specifies the base address and
+/// length of an area in memory.
+#[deprecated(
+    since = "0.24.0",
+    note = "`IoVec` is no longer used in the public interface, use `IoSlice` or `IoSliceMut` instead"
+)]
+#[repr(transparent)]
+#[allow(renamed_and_removed_lints)]
+#[allow(clippy::unknown_clippy_lints)]
+// Clippy false positive: https://github.com/rust-lang/rust-clippy/issues/8867
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct IoVec<T>(pub(crate) libc::iovec, PhantomData<T>);
+
+#[allow(deprecated)]
+impl<T> IoVec<T> {
+    /// View the `IoVec` as a Rust slice.
+    #[deprecated(
+        since = "0.24.0",
+        note = "Use the `Deref` impl of `IoSlice` or `IoSliceMut` instead"
+    )]
+    #[inline]
+    pub fn as_slice(&self) -> &[u8] {
+        use std::slice;
+
+        unsafe {
+            slice::from_raw_parts(self.0.iov_base as *const u8, self.0.iov_len)
+        }
+    }
+}
+
+#[allow(deprecated)]
+impl<'a> IoVec<&'a [u8]> {
+    /// Create an `IoVec` from a Rust slice.
+    #[deprecated(since = "0.24.0", note = "Use `IoSlice::new` instead")]
+    pub fn from_slice(buf: &'a [u8]) -> IoVec<&'a [u8]> {
+        IoVec(
+            libc::iovec {
+                iov_base: buf.as_ptr() as *mut c_void,
+                iov_len: buf.len() as size_t,
+            },
+            PhantomData,
+        )
+    }
+}
+
+#[allow(deprecated)]
+impl<'a> IoVec<&'a mut [u8]> {
+    /// Create an `IoVec` from a mutable Rust slice.
+    #[deprecated(since = "0.24.0", note = "Use `IoSliceMut::new` instead")]
+    pub fn from_mut_slice(buf: &'a mut [u8]) -> IoVec<&'a mut [u8]> {
+        IoVec(
+            libc::iovec {
+                iov_base: buf.as_ptr() as *mut c_void,
+                iov_len: buf.len() as size_t,
+            },
+            PhantomData,
+        )
+    }
+}
+
+// The only reason IoVec isn't automatically Send+Sync is because libc::iovec
+// contains raw pointers.
+#[allow(deprecated)]
+unsafe impl<T> Send for IoVec<T> where T: Send {}
+#[allow(deprecated)]
+unsafe impl<T> Sync for IoVec<T> where T: Sync {}
+
+feature! {
+#![feature = "process"]
+
+/// Write data directly to another process's virtual memory
+/// (see [`process_vm_writev`(2)]).
+///
+/// `local_iov` is a list of [`IoSlice`]s containing the data to be written,
+/// and `remote_iov` is a list of [`RemoteIoVec`]s identifying where the
+/// data should be written in the target process. On success, returns the
+/// number of bytes written, which will always be a whole
+/// number of `remote_iov` chunks.
+///
+/// This requires the same permissions as debugging the process using
+/// [ptrace]: you must either be a privileged process (with
+/// `CAP_SYS_PTRACE`), or you must be running as the same user as the
+/// target process and the OS must have unprivileged debugging enabled.
+///
+/// This function is only available on Linux and Android(SDK23+).
+///
+/// [`process_vm_writev`(2)]: https://man7.org/linux/man-pages/man2/process_vm_writev.2.html
+/// [ptrace]: ../ptrace/index.html
+/// [`IoSlice`]: https://doc.rust-lang.org/std/io/struct.IoSlice.html
+/// [`RemoteIoVec`]: struct.RemoteIoVec.html
+#[cfg(all(any(target_os = "linux", target_os = "android"), not(target_env = "uclibc")))]
+pub fn process_vm_writev(
+    pid: crate::unistd::Pid,
+    local_iov: &[IoSlice<'_>],
+    remote_iov: &[RemoteIoVec]) -> Result<usize>
+{
+    let res = unsafe {
+        libc::process_vm_writev(pid.into(),
+                                local_iov.as_ptr() as *const libc::iovec, local_iov.len() as libc::c_ulong,
+                                remote_iov.as_ptr() as *const libc::iovec, remote_iov.len() as libc::c_ulong, 0)
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+
+/// Read data directly from another process's virtual memory
+/// (see [`process_vm_readv`(2)]).
+///
+/// `local_iov` is a list of [`IoSliceMut`]s containing the buffer to copy
+/// data into, and `remote_iov` is a list of [`RemoteIoVec`]s identifying
+/// where the source data is in the target process. On success,
+/// returns the number of bytes written, which will always be a whole
+/// number of `remote_iov` chunks.
+///
+/// This requires the same permissions as debugging the process using
+/// [`ptrace`]: you must either be a privileged process (with
+/// `CAP_SYS_PTRACE`), or you must be running as the same user as the
+/// target process and the OS must have unprivileged debugging enabled.
+///
+/// This function is only available on Linux and Android(SDK23+).
+///
+/// [`process_vm_readv`(2)]: https://man7.org/linux/man-pages/man2/process_vm_readv.2.html
+/// [`ptrace`]: ../ptrace/index.html
+/// [`IoSliceMut`]: https://doc.rust-lang.org/std/io/struct.IoSliceMut.html
+/// [`RemoteIoVec`]: struct.RemoteIoVec.html
+#[cfg(all(any(target_os = "linux", target_os = "android"), not(target_env = "uclibc")))]
+pub fn process_vm_readv(
+    pid: crate::unistd::Pid,
+    local_iov: &mut [IoSliceMut<'_>],
+    remote_iov: &[RemoteIoVec]) -> Result<usize>
+{
+    let res = unsafe {
+        libc::process_vm_readv(pid.into(),
+                               local_iov.as_ptr() as *const libc::iovec, local_iov.len() as libc::c_ulong,
+                               remote_iov.as_ptr() as *const libc::iovec, remote_iov.len() as libc::c_ulong, 0)
+    };
+
+    Errno::result(res).map(|r| r as usize)
+}
+}