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Implement termios.tcgetwinsize/tcsetwinsize #8347

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Merged
youknowone merged 10 commits into from
Jul 26, 2026
Merged

Implement termios.tcgetwinsize/tcsetwinsize #8347

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d09e9b8
Implement termios.tcgetwinsize/tcsetwinsize
sigmaith Jul 22, 2026
0614732
Use ret < 0 convention for ioctl error checks in termios winsize
sigmaith Jul 22, 2026
2c555e5
Reject non-sequence size in tcsetwinsize
sigmaith Jul 22, 2026
414a869
Use `core::mem::zeroed` instead of `std::mem::zeroed`
sigmaith Jul 22, 2026
8af3f22
Use try_index for tcsetwinsize row/col conversion
sigmaith Jul 23, 2026
cbe201b
Mark test_fork/test_spawn_doesnt_hang as expected failures
sigmaith Jul 23, 2026
6888774
Use unittest.skip instead of expectedFailure for pty.fork() tests
sigmaith Jul 23, 2026
0fb01e0
Clarify skip reason for pty.fork() tests
sigmaith Jul 24, 2026
0a94885
Simplify tcgetwinsize/tcsetwinsize fd argument with Fildes destructuring
sigmaith Jul 24, 2026
ab4622a
Explain why pty.fork() tests use skip instead of expectedFailure
sigmaith Jul 25, 2026
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10 changes: 10 additions & 0 deletions Lib/test/test_pty.py
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Original file line number Diff line number Diff line change
Expand Up @@ -195,6 +195,11 @@ def test_openpty(self):
s2 = _readline(master_fd)
self.assertEqual(b'For my pet fish, Eric.\n', normalize_output(s2))

# skip (not expectedFailure) because the test still forks a real child
# process, which crashes on missing os.login_tty() inside the parallel
# test runner's worker process, corrupting its JSON reporting channel
# ("worker bug", reproducible under --slow-ci -j N; not under plain -m test).
@unittest.skip("TODO: RUSTPYTHON; pty.fork() calls os.login_tty(), which is not implemented")
def test_fork(self):
debug("calling pty.fork()")
pid, master_fd = pty.fork()
Expand Down Expand Up @@ -296,6 +301,11 @@ def test_master_read(self):

self.assertEqual(data, b"")

# skip (not expectedFailure) because the test still forks a real child
# process, which crashes on missing os.login_tty() inside the parallel
# test runner's worker process, corrupting its JSON reporting channel
# ("worker bug", reproducible under --slow-ci -j N; not under plain -m test).
@unittest.skip("TODO: RUSTPYTHON; pty.fork() calls os.login_tty(), which is not implemented")
def test_spawn_doesnt_hang(self):
# gh-140482: Do the test in a pty.fork() child to avoid messing
# with the interactive test runner's terminal settings.
Expand Down
4 changes: 0 additions & 4 deletions Lib/test/test_termios.py
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Original file line number Diff line number Diff line change
Expand Up @@ -221,7 +221,6 @@ def writer():
'output was not resumed')
self.assertEqual(os.read(rfd, 1024), b'def')

@unittest.expectedFailure # TODO: RUSTPYTHON; AttributeError: module 'termios' has no attribute 'tcgetwinsize'
def test_tcgetwinsize(self):
size = termios.tcgetwinsize(self.fd)
self.assertIsInstance(size, tuple)
Expand All @@ -230,22 +229,19 @@ def test_tcgetwinsize(self):
self.assertIsInstance(size[1], int)
self.assertEqual(termios.tcgetwinsize(self.stream), size)

@unittest.expectedFailure # TODO: RUSTPYTHON; AttributeError: module 'termios' has no attribute 'tcgetwinsize'
def test_tcgetwinsize_errors(self):
self.assertRaisesTermiosError(errno.ENOTTY, termios.tcgetwinsize, self.bad_fd)
self.assertRaises(ValueError, termios.tcgetwinsize, -1)
self.assertRaises(OverflowError, termios.tcgetwinsize, 2**1000)
self.assertRaises(TypeError, termios.tcgetwinsize, object())
self.assertRaises(TypeError, termios.tcgetwinsize)

@unittest.expectedFailure # TODO: RUSTPYTHON; AttributeError: module 'termios' has no attribute 'tcgetwinsize'
def test_tcsetwinsize(self):
size = termios.tcgetwinsize(self.fd)
termios.tcsetwinsize(self.fd, size)
termios.tcsetwinsize(self.fd, list(size))
termios.tcsetwinsize(self.stream, size)

@unittest.expectedFailure # TODO: RUSTPYTHON; AttributeError: module 'termios' has no attribute 'tcgetwinsize'
def test_tcsetwinsize_errors(self):
size = termios.tcgetwinsize(self.fd)
self.assertRaises(TypeError, termios.tcsetwinsize, self.fd, size[:-1])
Expand Down
24 changes: 24 additions & 0 deletions crates/host_env/src/termios.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -165,3 +165,27 @@ pub fn tcflush(fd: i32, queue: i32) -> std::io::Result<()> {
pub fn tcflow(fd: i32, action: i32) -> std::io::Result<()> {
::termios::tcflow(fd, action)
}

pub fn tcgetwinsize(fd: i32) -> std::io::Result<(u16, u16)> {
let mut size: libc::winsize = unsafe { core::mem::zeroed() };
let ret = unsafe { libc::ioctl(fd, TIOCGWINSZ as _, &mut size) };
if ret < 0 {
return Err(std::io::Error::last_os_error());
}
Ok((size.ws_row, size.ws_col))
}

pub fn tcsetwinsize(fd: i32, row: u16, col: u16) -> std::io::Result<()> {
let mut size: libc::winsize = unsafe { core::mem::zeroed() };
let ret = unsafe { libc::ioctl(fd, TIOCGWINSZ as _, &mut size) };
if ret < 0 {
return Err(std::io::Error::last_os_error());
}
size.ws_row = row;
size.ws_col = col;
let ret = unsafe { libc::ioctl(fd, TIOCSWINSZ as _, &size) };
if ret < 0 {
return Err(std::io::Error::last_os_error());
}
Ok(())
}
22 changes: 22 additions & 0 deletions crates/stdlib/src/termios.rs
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Expand Up @@ -268,6 +268,28 @@ mod termios {
Ok(())
}

#[pyfunction]
fn tcgetwinsize(Fildes(fd): Fildes, vm: &VirtualMachine) -> PyResult<(u16, u16)> {
let size = host_termios::tcgetwinsize(fd).map_err(|e| termios_error(e, vm))?;
Ok(size)
}

#[pyfunction]
fn tcsetwinsize(Fildes(fd): Fildes, size: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
let seq = size.try_sequence(vm)?;
if seq.length(vm)? != 2 {
return Err(vm.new_type_error("tcsetwinsize: size must be a 2 element sequence"));
}
Comment on lines +278 to +282

@youknowone youknowone Jul 25, 2026

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size also is looking like a pair of number, always.

Suggested change
fn tcsetwinsize(Fildes(fd): Fildes, size: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
let seq = size.try_sequence(vm)?;
if seq.length(vm)? != 2 {
return Err(vm.new_type_error("tcsetwinsize: size must be a 2 element sequence"));
}
fn tcsetwinsize(Fildes(fd): Fildes, size: (u16, u16), vm: &VirtualMachine) -> PyResult<()> {
let (row, col) = size;

@sigmaith sigmaith Jul 25, 2026 •
edited
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Tested it locally, and it behaves differently via FromArgs impl than a tuple or list argument would.

@youknowone youknowone Jul 26, 2026

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ah, you are right. I am sorry.

let row = seq.get_item(0, vm)?;
let col = seq.get_item(1, vm)?;

let row: u16 = row.try_index(vm)?.try_to_primitive(vm)?;
let col: u16 = col.try_index(vm)?.try_to_primitive(vm)?;

host_termios::tcsetwinsize(fd, row, col).map_err(|e| termios_error(e, vm))?;
Ok(())
}

fn termios_error(err: std::io::Error, vm: &VirtualMachine) -> PyBaseExceptionRef {
vm.new_os_subtype_error(
error_type(vm),
Expand Down
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