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//! linux_raw syscalls supporting `rustix::io`.
//!
//! # Safety
//!
//! See the `rustix::backend` module documentation for details.
#![allow(unsafe_code)]
#![allow(clippy::undocumented_unsafe_blocks)]
#[cfg(target_pointer_width = "64")]
use crate::backend::conv::loff_t_from_u64;
#[cfg(all(
target_pointer_width = "32",
any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6"),
))]
use crate::backend::conv::zero;
use crate::backend::conv::{
c_uint, pass_usize, raw_fd, ret, ret_c_int, ret_c_uint, ret_discarded_fd, ret_owned_fd,
ret_usize, slice,
};
#[cfg(target_pointer_width = "32")]
use crate::backend::conv::{hi, lo};
use crate::backend::{c, MAX_IOV};
use crate::fd::{AsFd, BorrowedFd, OwnedFd, RawFd};
use crate::io::{self, DupFlags, FdFlags, IoSlice, IoSliceMut, ReadWriteFlags};
use crate::ioctl::{IoctlOutput, RawOpcode};
#[cfg(all(feature = "fs", feature = "net"))]
use crate::net::{RecvFlags, SendFlags};
use core::cmp;
use linux_raw_sys::general::{F_DUPFD_CLOEXEC, F_GETFD, F_SETFD};
#[inline]
pub(crate) unsafe fn read(fd: BorrowedFd<'_>, buf: *mut u8, len: usize) -> io::Result<usize> {
ret_usize(syscall!(__NR_read, fd, buf, pass_usize(len)))
}
#[inline]
pub(crate) unsafe fn pread(
fd: BorrowedFd<'_>,
buf: *mut u8,
len: usize,
pos: u64,
) -> io::Result<usize> {
#[cfg(all(
target_pointer_width = "32",
any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6"),
))]
{
ret_usize(syscall!(
__NR_pread64,
fd,
buf,
pass_usize(len),
zero(),
hi(pos),
lo(pos)
))
}
#[cfg(all(
target_pointer_width = "32",
not(any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6")),
))]
{
ret_usize(syscall!(
__NR_pread64,
fd,
buf,
pass_usize(len),
hi(pos),
lo(pos)
))
}
#[cfg(target_pointer_width = "64")]
ret_usize(syscall!(
__NR_pread64,
fd,
buf,
pass_usize(len),
loff_t_from_u64(pos)
))
}
#[inline]
pub(crate) fn readv(fd: BorrowedFd<'_>, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
let (bufs_addr, bufs_len) = slice(&bufs[..cmp::min(bufs.len(), MAX_IOV)]);
unsafe { ret_usize(syscall!(__NR_readv, fd, bufs_addr, bufs_len)) }
}
#[inline]
pub(crate) fn preadv(
fd: BorrowedFd<'_>,
bufs: &mut [IoSliceMut<'_>],
pos: u64,
) -> io::Result<usize> {
let (bufs_addr, bufs_len) = slice(&bufs[..cmp::min(bufs.len(), MAX_IOV)]);
// Unlike the plain "p" functions, the "pv" functions pass their offset in
// an endian-independent way, and always in two registers.
unsafe {
ret_usize(syscall!(
__NR_preadv,
fd,
bufs_addr,
bufs_len,
pass_usize(pos as usize),
pass_usize((pos >> 32) as usize)
))
}
}
#[inline]
pub(crate) fn preadv2(
fd: BorrowedFd<'_>,
bufs: &mut [IoSliceMut<'_>],
pos: u64,
flags: ReadWriteFlags,
) -> io::Result<usize> {
let (bufs_addr, bufs_len) = slice(&bufs[..cmp::min(bufs.len(), MAX_IOV)]);
// Unlike the plain "p" functions, the "pv" functions pass their offset in
// an endian-independent way, and always in two registers.
unsafe {
ret_usize(syscall!(
__NR_preadv2,
fd,
bufs_addr,
bufs_len,
pass_usize(pos as usize),
pass_usize((pos >> 32) as usize),
flags
))
}
}
#[inline]
pub(crate) fn write(fd: BorrowedFd<'_>, buf: &[u8]) -> io::Result<usize> {
let (buf_addr, buf_len) = slice(buf);
unsafe { ret_usize(syscall_readonly!(__NR_write, fd, buf_addr, buf_len)) }
}
#[inline]
pub(crate) fn pwrite(fd: BorrowedFd<'_>, buf: &[u8], pos: u64) -> io::Result<usize> {
let (buf_addr, buf_len) = slice(buf);
#[cfg(all(
target_pointer_width = "32",
any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6"),
))]
unsafe {
ret_usize(syscall_readonly!(
__NR_pwrite64,
fd,
buf_addr,
buf_len,
zero(),
hi(pos),
lo(pos)
))
}
#[cfg(all(
target_pointer_width = "32",
not(any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6")),
))]
unsafe {
ret_usize(syscall_readonly!(
__NR_pwrite64,
fd,
buf_addr,
buf_len,
hi(pos),
lo(pos)
))
}
#[cfg(target_pointer_width = "64")]
unsafe {
ret_usize(syscall_readonly!(
__NR_pwrite64,
fd,
buf_addr,
buf_len,
loff_t_from_u64(pos)
))
}
}
#[inline]
pub(crate) fn writev(fd: BorrowedFd<'_>, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
let (bufs_addr, bufs_len) = slice(&bufs[..cmp::min(bufs.len(), MAX_IOV)]);
unsafe { ret_usize(syscall_readonly!(__NR_writev, fd, bufs_addr, bufs_len)) }
}
#[inline]
pub(crate) fn pwritev(fd: BorrowedFd<'_>, bufs: &[IoSlice<'_>], pos: u64) -> io::Result<usize> {
let (bufs_addr, bufs_len) = slice(&bufs[..cmp::min(bufs.len(), MAX_IOV)]);
// Unlike the plain "p" functions, the "pv" functions pass their offset in
// an endian-independent way, and always in two registers.
unsafe {
ret_usize(syscall_readonly!(
__NR_pwritev,
fd,
bufs_addr,
bufs_len,
pass_usize(pos as usize),
pass_usize((pos >> 32) as usize)
))
}
}
#[inline]
pub(crate) fn pwritev2(
fd: BorrowedFd<'_>,
bufs: &[IoSlice<'_>],
pos: u64,
flags: ReadWriteFlags,
) -> io::Result<usize> {
let (bufs_addr, bufs_len) = slice(&bufs[..cmp::min(bufs.len(), MAX_IOV)]);
// Unlike the plain "p" functions, the "pv" functions pass their offset in
// an endian-independent way, and always in two registers.
unsafe {
ret_usize(syscall_readonly!(
__NR_pwritev2,
fd,
bufs_addr,
bufs_len,
pass_usize(pos as usize),
pass_usize((pos >> 32) as usize),
flags
))
}
}
#[inline]
pub(crate) unsafe fn close(fd: RawFd) {
// See the documentation for [`io::close`] for why errors are ignored.
syscall_readonly!(__NR_close, raw_fd(fd)).decode_void();
}
#[inline]
pub(crate) unsafe fn ioctl(
fd: BorrowedFd<'_>,
request: RawOpcode,
arg: *mut c::c_void,
) -> io::Result<IoctlOutput> {
ret_c_int(syscall!(__NR_ioctl, fd, c_uint(request), arg))
}
#[inline]
pub(crate) unsafe fn ioctl_readonly(
fd: BorrowedFd<'_>,
request: RawOpcode,
arg: *mut c::c_void,
) -> io::Result<IoctlOutput> {
ret_c_int(syscall_readonly!(__NR_ioctl, fd, c_uint(request), arg))
}
#[cfg(all(feature = "fs", feature = "net"))]
pub(crate) fn is_read_write(fd: BorrowedFd<'_>) -> io::Result<(bool, bool)> {
let (mut read, mut write) = crate::fs::fd::_is_file_read_write(fd)?;
let mut not_socket = false;
if read {
// Do a `recv` with `PEEK` and `DONTWAIT` for 1 byte. A 0 indicates
// the read side is shut down; an `EWOULDBLOCK` indicates the read
// side is still open.
let mut buf = [core::mem::MaybeUninit::<u8>::uninit()];
match unsafe {
crate::backend::net::syscalls::recv(
fd,
buf.as_mut_ptr() as *mut u8,
1,
RecvFlags::PEEK | RecvFlags::DONTWAIT,
)
} {
Ok(0) => read = false,
Err(err) => {
#[allow(unreachable_patterns)] // `EAGAIN` may equal `EWOULDBLOCK`
match err {
io::Errno::AGAIN | io::Errno::WOULDBLOCK => (),
io::Errno::NOTSOCK => not_socket = true,
_ => return Err(err),
}
}
Ok(_) => (),
}
}
if write && !not_socket {
// Do a `send` with `DONTWAIT` for 0 bytes. An `EPIPE` indicates
// the write side is shut down.
#[allow(unreachable_patterns)] // `EAGAIN` equals `EWOULDBLOCK`
match crate::backend::net::syscalls::send(fd, &[], SendFlags::DONTWAIT) {
Err(io::Errno::AGAIN | io::Errno::WOULDBLOCK | io::Errno::NOTSOCK) => (),
Err(io::Errno::PIPE) => write = false,
Err(err) => return Err(err),
Ok(_) => (),
}
}
Ok((read, write))
}
#[inline]
pub(crate) fn dup(fd: BorrowedFd<'_>) -> io::Result<OwnedFd> {
unsafe { ret_owned_fd(syscall_readonly!(__NR_dup, fd)) }
}
#[allow(clippy::needless_pass_by_ref_mut)]
#[inline]
pub(crate) fn dup2(fd: BorrowedFd<'_>, new: &mut OwnedFd) -> io::Result<()> {
#[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))]
{
// We don't need to worry about the difference between `dup2` and
// `dup3` when the file descriptors are equal because we have an
// `&mut OwnedFd` which means `fd` doesn't alias it.
dup3(fd, new, DupFlags::empty())
}
#[cfg(not(any(target_arch = "aarch64", target_arch = "riscv64")))]
unsafe {
ret_discarded_fd(syscall_readonly!(__NR_dup2, fd, new.as_fd()))
}
}
#[allow(clippy::needless_pass_by_ref_mut)]
#[inline]
pub(crate) fn dup3(fd: BorrowedFd<'_>, new: &mut OwnedFd, flags: DupFlags) -> io::Result<()> {
unsafe { ret_discarded_fd(syscall_readonly!(__NR_dup3, fd, new.as_fd(), flags)) }
}
#[inline]
pub(crate) fn fcntl_getfd(fd: BorrowedFd<'_>) -> io::Result<FdFlags> {
#[cfg(target_pointer_width = "32")]
unsafe {
ret_c_uint(syscall_readonly!(__NR_fcntl64, fd, c_uint(F_GETFD)))
.map(FdFlags::from_bits_retain)
}
#[cfg(target_pointer_width = "64")]
unsafe {
ret_c_uint(syscall_readonly!(__NR_fcntl, fd, c_uint(F_GETFD)))
.map(FdFlags::from_bits_retain)
}
}
#[inline]
pub(crate) fn fcntl_setfd(fd: BorrowedFd<'_>, flags: FdFlags) -> io::Result<()> {
#[cfg(target_pointer_width = "32")]
unsafe {
ret(syscall_readonly!(__NR_fcntl64, fd, c_uint(F_SETFD), flags))
}
#[cfg(target_pointer_width = "64")]
unsafe {
ret(syscall_readonly!(__NR_fcntl, fd, c_uint(F_SETFD), flags))
}
}
#[inline]
pub(crate) fn fcntl_dupfd_cloexec(fd: BorrowedFd<'_>, min: RawFd) -> io::Result<OwnedFd> {
#[cfg(target_pointer_width = "32")]
unsafe {
ret_owned_fd(syscall_readonly!(
__NR_fcntl64,
fd,
c_uint(F_DUPFD_CLOEXEC),
raw_fd(min)
))
}
#[cfg(target_pointer_width = "64")]
unsafe {
ret_owned_fd(syscall_readonly!(
__NR_fcntl,
fd,
c_uint(F_DUPFD_CLOEXEC),
raw_fd(min)
))
}
}