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//! linux_raw syscalls supporting `rustix::termios`.
//!
//! # Safety
//!
//! See the `rustix::backend` module documentation for details.
#![allow(unsafe_code, clippy::undocumented_unsafe_blocks)]
use crate::backend::c;
use crate::backend::conv::{by_ref, c_uint, ret};
use crate::fd::BorrowedFd;
use crate::io;
use crate::pid::Pid;
#[cfg(all(feature = "alloc", feature = "procfs"))]
use crate::procfs;
use crate::termios::{
Action, ControlModes, InputModes, LocalModes, OptionalActions, OutputModes, QueueSelector,
SpecialCodeIndex, Termios, Winsize,
};
#[cfg(all(feature = "alloc", feature = "procfs"))]
use crate::{ffi::CStr, fs::FileType, path::DecInt};
use core::mem::MaybeUninit;
use linux_raw_sys::general::IBSHIFT;
use linux_raw_sys::ioctl::{
TCFLSH, TCSBRK, TCXONC, TIOCGPGRP, TIOCGSID, TIOCGWINSZ, TIOCSPGRP, TIOCSWINSZ,
};
#[inline]
pub(crate) fn tcgetwinsize(fd: BorrowedFd<'_>) -> io::Result<Winsize> {
unsafe {
let mut result = MaybeUninit::<Winsize>::uninit();
ret(syscall!(__NR_ioctl, fd, c_uint(TIOCGWINSZ), &mut result))?;
Ok(result.assume_init())
}
}
#[inline]
pub(crate) fn tcgetattr(fd: BorrowedFd<'_>) -> io::Result<Termios> {
unsafe {
let mut result = MaybeUninit::<Termios>::uninit();
// QEMU's `TCGETS2` doesn't currently set `input_speed` or
// `output_speed` on PowerPC, so zero out the fields ourselves.
#[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))]
{
result.write(core::mem::zeroed());
}
ret(syscall!(__NR_ioctl, fd, c_uint(c::TCGETS2), &mut result))?;
let result = result.assume_init();
// QEMU's `TCGETS2` doesn't currently set `input_speed` or
// `output_speed` on PowerPC, so set them manually if we can.
#[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))]
let result = {
use crate::termios::speed;
let mut result = result;
if result.output_speed == 0 && (result.control_modes.bits() & c::CBAUD) != c::BOTHER {
if let Some(output_speed) = speed::decode(result.control_modes.bits() & c::CBAUD) {
result.output_speed = output_speed;
}
}
if result.input_speed == 0
&& ((result.control_modes.bits() & c::CIBAUD) >> c::IBSHIFT) != c::BOTHER
{
// For input speeds, `B0` is special-cased to mean the input
// speed is the same as the output speed.
if ((result.control_modes.bits() & c::CIBAUD) >> c::IBSHIFT) == c::B0 {
result.input_speed = result.output_speed;
} else if let Some(input_speed) =
speed::decode((result.control_modes.bits() & c::CIBAUD) >> c::IBSHIFT)
{
result.input_speed = input_speed;
}
}
result
};
Ok(result)
}
}
#[inline]
pub(crate) fn tcgetpgrp(fd: BorrowedFd<'_>) -> io::Result<Pid> {
unsafe {
let mut result = MaybeUninit::<c::pid_t>::uninit();
ret(syscall!(__NR_ioctl, fd, c_uint(TIOCGPGRP), &mut result))?;
let pid = result.assume_init();
// This doesn't appear to be documented, but it appears `tcsetpgrp` can
// succceed and set the pid to 0 if we pass it a pseudo-terminal device
// fd. For now, fail with `OPNOTSUPP`.
if pid == 0 {
return Err(io::Errno::OPNOTSUPP);
}
Ok(Pid::from_raw_unchecked(pid))
}
}
#[inline]
pub(crate) fn tcsetattr(
fd: BorrowedFd<'_>,
optional_actions: OptionalActions,
termios: &Termios,
) -> io::Result<()> {
// Translate from `optional_actions` into an ioctl request code. On MIPS,
// `optional_actions` already has `TCGETS` added to it.
let request = linux_raw_sys::ioctl::TCSETS2
+ if cfg!(any(
target_arch = "mips",
target_arch = "mips32r6",
target_arch = "mips64",
target_arch = "mips64r6"
)) {
optional_actions as u32 - linux_raw_sys::ioctl::TCSETS
} else {
optional_actions as u32
};
unsafe {
ret(syscall_readonly!(
__NR_ioctl,
fd,
c_uint(request),
by_ref(termios)
))
}
}
#[inline]
pub(crate) fn tcsendbreak(fd: BorrowedFd<'_>) -> io::Result<()> {
unsafe { ret(syscall_readonly!(__NR_ioctl, fd, c_uint(TCSBRK), c_uint(0))) }
}
#[inline]
pub(crate) fn tcdrain(fd: BorrowedFd<'_>) -> io::Result<()> {
unsafe { ret(syscall_readonly!(__NR_ioctl, fd, c_uint(TCSBRK), c_uint(1))) }
}
#[inline]
pub(crate) fn tcflush(fd: BorrowedFd<'_>, queue_selector: QueueSelector) -> io::Result<()> {
unsafe {
ret(syscall_readonly!(
__NR_ioctl,
fd,
c_uint(TCFLSH),
c_uint(queue_selector as u32)
))
}
}
#[inline]
pub(crate) fn tcflow(fd: BorrowedFd<'_>, action: Action) -> io::Result<()> {
unsafe {
ret(syscall_readonly!(
__NR_ioctl,
fd,
c_uint(TCXONC),
c_uint(action as u32)
))
}
}
#[inline]
pub(crate) fn tcgetsid(fd: BorrowedFd<'_>) -> io::Result<Pid> {
unsafe {
let mut result = MaybeUninit::<c::pid_t>::uninit();
ret(syscall!(__NR_ioctl, fd, c_uint(TIOCGSID), &mut result))?;
let pid = result.assume_init();
Ok(Pid::from_raw_unchecked(pid))
}
}
#[inline]
pub(crate) fn tcsetwinsize(fd: BorrowedFd<'_>, winsize: Winsize) -> io::Result<()> {
unsafe {
ret(syscall_readonly!(
__NR_ioctl,
fd,
c_uint(TIOCSWINSZ),
by_ref(&winsize)
))
}
}
#[inline]
pub(crate) fn tcsetpgrp(fd: BorrowedFd<'_>, pid: Pid) -> io::Result<()> {
let raw_pid: c::c_int = pid.as_raw_nonzero().get();
unsafe {
ret(syscall_readonly!(
__NR_ioctl,
fd,
c_uint(TIOCSPGRP),
by_ref(&raw_pid)
))
}
}
/// A wrapper around a conceptual `cfsetspeed` which handles an arbitrary
/// integer speed value.
#[inline]
pub(crate) fn set_speed(termios: &mut Termios, arbitrary_speed: u32) -> io::Result<()> {
let encoded_speed = crate::termios::speed::encode(arbitrary_speed).unwrap_or(c::BOTHER);
debug_assert_eq!(encoded_speed & !c::CBAUD, 0);
termios.control_modes -= ControlModes::from_bits_retain(c::CBAUD | c::CIBAUD);
termios.control_modes |=
ControlModes::from_bits_retain(encoded_speed | (encoded_speed << IBSHIFT));
termios.input_speed = arbitrary_speed;
termios.output_speed = arbitrary_speed;
Ok(())
}
/// A wrapper around a conceptual `cfsetospeed` which handles an arbitrary
/// integer speed value.
#[inline]
pub(crate) fn set_output_speed(termios: &mut Termios, arbitrary_speed: u32) -> io::Result<()> {
let encoded_speed = crate::termios::speed::encode(arbitrary_speed).unwrap_or(c::BOTHER);
debug_assert_eq!(encoded_speed & !c::CBAUD, 0);
termios.control_modes -= ControlModes::from_bits_retain(c::CBAUD);
termios.control_modes |= ControlModes::from_bits_retain(encoded_speed);
termios.output_speed = arbitrary_speed;
Ok(())
}
/// A wrapper around a conceptual `cfsetispeed` which handles an arbitrary
/// integer speed value.
#[inline]
pub(crate) fn set_input_speed(termios: &mut Termios, arbitrary_speed: u32) -> io::Result<()> {
let encoded_speed = crate::termios::speed::encode(arbitrary_speed).unwrap_or(c::BOTHER);
debug_assert_eq!(encoded_speed & !c::CBAUD, 0);
termios.control_modes -= ControlModes::from_bits_retain(c::CIBAUD);
termios.control_modes |= ControlModes::from_bits_retain(encoded_speed << IBSHIFT);
termios.input_speed = arbitrary_speed;
Ok(())
}
#[inline]
pub(crate) fn cfmakeraw(termios: &mut Termios) {
// From the Linux [`cfmakeraw` manual page]:
//
termios.input_modes -= InputModes::IGNBRK
| InputModes::BRKINT
| InputModes::PARMRK
| InputModes::ISTRIP
| InputModes::INLCR
| InputModes::IGNCR
| InputModes::ICRNL
| InputModes::IXON;
termios.output_modes -= OutputModes::OPOST;
termios.local_modes -= LocalModes::ECHO
| LocalModes::ECHONL
| LocalModes::ICANON
| LocalModes::ISIG
| LocalModes::IEXTEN;
termios.control_modes -= ControlModes::CSIZE | ControlModes::PARENB;
termios.control_modes |= ControlModes::CS8;
// Musl and glibc also do these:
termios.special_codes[SpecialCodeIndex::VMIN] = 1;
termios.special_codes[SpecialCodeIndex::VTIME] = 0;
}
#[inline]
pub(crate) fn isatty(fd: BorrowedFd<'_>) -> bool {
// On error, Linux will return either `EINVAL` (2.6.32) or `ENOTTY`
// (otherwise), because we assume we're never passing an invalid
// file descriptor (which would get `EBADF`). Either way, an error
// means we don't have a tty.
tcgetwinsize(fd).is_ok()
}
#[cfg(all(feature = "alloc", feature = "procfs"))]
pub(crate) fn ttyname(fd: BorrowedFd<'_>, buf: &mut [MaybeUninit<u8>]) -> io::Result<usize> {
let fd_stat = crate::backend::fs::syscalls::fstat(fd)?;
// Quick check: if `fd` isn't a character device, it's not a tty.
if FileType::from_raw_mode(fd_stat.st_mode) != FileType::CharacterDevice {
return Err(io::Errno::NOTTY);
}
// Check that `fd` is really a tty.
tcgetwinsize(fd)?;
// Get a fd to "/proc/self/fd".
let proc_self_fd = procfs::proc_self_fd()?;
// Gather the ttyname by reading the "fd" file inside `proc_self_fd`.
let r = crate::backend::fs::syscalls::readlinkat(
proc_self_fd,
DecInt::from_fd(fd).as_c_str(),
buf,
)?;
// If the number of bytes is equal to the buffer length, truncation may
// have occurred. This check also ensures that we have enough space for
// adding a NUL terminator.
if r == buf.len() {
return Err(io::Errno::RANGE);
}
// `readlinkat` returns the number of bytes placed in the buffer.
// NUL-terminate the string at that offset.
buf[r].write(b'\0');
// Check that the path we read refers to the same file as `fd`.
{
// SAFETY: We just wrote the NUL byte above
let path = unsafe { CStr::from_ptr(buf.as_ptr().cast()) };
let path_stat = crate::backend::fs::syscalls::stat(path)?;
if path_stat.st_dev != fd_stat.st_dev || path_stat.st_ino != fd_stat.st_ino {
return Err(io::Errno::NODEV);
}
}
Ok(r)
}