Initial commit for fern

src/libsh/sys.rs

@@ -0,0 +1,51 @@
+use std::fmt::Display;
+
+use crate::prelude::*;
+
+pub const SIG_EXIT_OFFSET: i32 = 128;
+
+pub fn get_bin_path(command: &str, shenv: &ShEnv) -> Option<PathBuf> {
+	let env = shenv.vars().env();
+	let path_var = env.get("PATH")?;
+	let mut paths = path_var.split(':');
+	while let Some(raw_path) = paths.next() {
+		let mut path = PathBuf::from(raw_path);
+		path.push(command);
+		//TODO: handle this unwrap
+		if path.exists() {
+			return Some(path)
+		}
+	}
+	None
+}
+
+pub fn write_out(text: impl Display) -> ShResult<()> {
+	write(borrow_fd(1), text.to_string().as_bytes())?;
+	Ok(())
+}
+
+pub fn write_err(text: impl Display) -> ShResult<()> {
+	write(borrow_fd(2), text.to_string().as_bytes())?;
+	Ok(())
+}
+
+/// Return is `readpipe`, `writepipe`
+/// Contains all of the necessary boilerplate for grabbing two pipe fds using libc::pipe()
+pub fn c_pipe() -> Result<(RawFd,RawFd),Errno> {
+	let mut pipes: [i32;2] = [0;2];
+	let ret = unsafe { libc::pipe(pipes.as_mut_ptr()) };
+	if ret < 0 {
+		return Err(Errno::from_raw(ret))
+	}
+	Ok((pipes[0],pipes[1]))
+}
+
+pub fn execvpe(cmd: String, argv: Vec<String>, envp: Vec<String>) -> Result<(),Errno> {
+	let cmd_raw = CString::new(cmd).unwrap();
+
+	let argv = argv.into_iter().map(|arg| CString::new(arg).unwrap()).collect::<Vec<CString>>();
+	let envp = envp.into_iter().map(|var| CString::new(var).unwrap()).collect::<Vec<CString>>();
+
+	nix::unistd::execvpe(&cmd_raw, &argv, &envp).unwrap();
+	Ok(())
+}