3 files changed, 226 insertions, 0 deletions
diff --git a/src/blocking/command.rs b/src/blocking/command.rs
new file mode 100644
index 0000000..3de0f3e
--- /dev/null
+++ b/src/blocking/command.rs
@@ -0,0 +1,156 @@
+use std::os::unix::process::CommandExt as _;
+
+pub struct Command {
+    inner: std::process::Command,
+    stdin: Option<std::process::Stdio>,
+    stdout: Option<std::process::Stdio>,
+    stderr: Option<std::process::Stdio>,
+}
+
+impl Command {
+    pub fn new<S: AsRef<std::ffi::OsStr>>(program: S) -> Self {
+        Self {
+            inner: std::process::Command::new(program),
+            stdin: None,
+            stdout: None,
+            stderr: None,
+        }
+    }
+
+    pub fn arg<S: AsRef<std::ffi::OsStr>>(&mut self, arg: S) -> &mut Self {
+        self.inner.arg(arg);
+        self
+    }
+
+    pub fn args<I, S>(&mut self, args: I) -> &mut Self
+    where
+        I: IntoIterator<Item = S>,
+        S: AsRef<std::ffi::OsStr>,
+    {
+        self.inner.args(args);
+        self
+    }
+
+    pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Self
+    where
+        K: AsRef<std::ffi::OsStr>,
+        V: AsRef<std::ffi::OsStr>,
+    {
+        self.inner.env(key, val);
+        self
+    }
+
+    pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Self
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: AsRef<std::ffi::OsStr>,
+        V: AsRef<std::ffi::OsStr>,
+    {
+        self.inner.envs(vars);
+        self
+    }
+
+    pub fn env_remove<K: AsRef<std::ffi::OsStr>>(
+        &mut self,
+        key: K,
+    ) -> &mut Self {
+        self.inner.env_remove(key);
+        self
+    }
+
+    pub fn env_clear(&mut self) -> &mut Self {
+        self.inner.env_clear();
+        self
+    }
+
+    pub fn current_dir<P: AsRef<std::path::Path>>(
+        &mut self,
+        dir: P,
+    ) -> &mut Self {
+        self.inner.current_dir(dir);
+        self
+    }
+
+    pub fn stdin<T: Into<std::process::Stdio>>(
+        &mut self,
+        cfg: Option<T>,
+    ) -> &mut Self {
+        self.stdin = cfg.map(Into::into);
+        self
+    }
+
+    pub fn stdout<T: Into<std::process::Stdio>>(
+        &mut self,
+        cfg: Option<T>,
+    ) -> &mut Self {
+        self.stdout = cfg.map(Into::into);
+        self
+    }
+
+    pub fn stderr<T: Into<std::process::Stdio>>(
+        &mut self,
+        cfg: Option<T>,
+    ) -> &mut Self {
+        self.stderr = cfg.map(Into::into);
+        self
+    }
+
+    pub fn spawn(
+        &mut self,
+        pty: crate::blocking::Pty,
+    ) -> crate::Result<Child> {
+        let (stdin, stdout, stderr, pre_exec) = crate::sys::setup_subprocess(
+            &pty,
+            pty.pts().map_err(crate::error::spawn)?,
+        )
+        .map_err(crate::error::spawn)?;
+
+        self.inner.stdin(self.stdin.take().unwrap_or(stdin));
+        self.inner.stdout(self.stdout.take().unwrap_or(stdout));
+        self.inner.stderr(self.stderr.take().unwrap_or(stderr));
+
+        // safe because setsid() and close() are async-signal-safe functions
+        // and ioctl() is a raw syscall (which is inherently
+        // async-signal-safe).
+        unsafe { self.inner.pre_exec(pre_exec) };
+
+        let child = self.inner.spawn().map_err(crate::error::spawn)?;
+
+        Ok(Child::new(child, pty))
+    }
+}
+
+pub struct Child {
+    inner: std::process::Child,
+    pty: crate::blocking::Pty,
+}
+
+impl Child {
+    fn new(inner: std::process::Child, pty: crate::blocking::Pty) -> Self {
+        Self { inner, pty }
+    }
+
+    #[must_use]
+    pub fn pty(&self) -> &crate::blocking::Pty {
+        &self.pty
+    }
+
+    #[must_use]
+    pub fn pty_mut(&mut self) -> &mut crate::blocking::Pty {
+        &mut self.pty
+    }
+}
+
+impl std::ops::Deref for Child {
+    type Target = std::process::Child;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl std::ops::DerefMut for Child {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.inner
+    }
+}
diff --git a/src/blocking/mod.rs b/src/blocking/mod.rs
new file mode 100644
index 0000000..a45b132
--- /dev/null
+++ b/src/blocking/mod.rs
@@ -0,0 +1,4 @@
+mod command;
+pub use command::{Child, Command};
+mod pty;
+pub use pty::Pty;
diff --git a/src/blocking/pty.rs b/src/blocking/pty.rs
new file mode 100644
index 0000000..7900b50
--- /dev/null
+++ b/src/blocking/pty.rs
@@ -0,0 +1,66 @@
+pub struct Pty {
+    pt: std::fs::File,
+    ptsname: std::path::PathBuf,
+}
+
+impl Pty {
+    pub fn new() -> crate::Result<Self> {
+        let (pt, ptsname) =
+            crate::sys::create_pt().map_err(crate::error::create_pty)?;
+        Ok(Self { pt, ptsname })
+    }
+
+    pub fn resize(&self, size: crate::Size) -> crate::error::Result<()> {
+        crate::sys::set_term_size(self, size)
+            .map_err(crate::error::set_term_size)
+    }
+
+    pub(crate) fn pts(&self) -> std::io::Result<std::fs::File> {
+        let fh = std::fs::OpenOptions::new()
+            .read(true)
+            .write(true)
+            .open(&self.ptsname)?;
+        Ok(fh)
+    }
+}
+
+impl std::ops::Deref for Pty {
+    type Target = std::fs::File;
+
+    fn deref(&self) -> &Self::Target {
+        &self.pt
+    }
+}
+
+impl std::ops::DerefMut for Pty {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.pt
+    }
+}
+
+impl std::os::unix::io::AsRawFd for Pty {
+    fn as_raw_fd(&self) -> std::os::unix::io::RawFd {
+        self.pt.as_raw_fd()
+    }
+}
+
+// there is a Read impl for &std::fs::File, but without this explicit impl,
+// rust finds the Read impl for std::fs::File first, and then complains that
+// it requires &mut self, because method resolution/autoderef doesn't take
+// mutability into account
+impl std::io::Read for &Pty {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        (&self.pt).read(buf)
+    }
+}
+
+// same as above
+impl std::io::Write for &Pty {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        (&self.pt).write(buf)
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        (&self.pt).flush()
+    }
+}