Various additions and improvements

src/builtin/cd.rs

@@ -0,0 +1,29 @@
+use crate::{jobs::{ChildProc, JobBldr}, libsh::error::{ShErr, ShErrKind, ShResult}, parse::{execute::prepare_argv, NdRule, Node}, prelude::*, state::write_vars};
+
+pub fn cd(node: Node, job: &mut JobBldr) -> ShResult<()> {
+	let NdRule::Command { assignments: _, argv } = node.class else {
+		unreachable!()
+	};
+
+	let child_pgid = if let Some(pgid) = job.pgid() {
+		pgid
+	} else {
+		job.set_pgid(Pid::this());
+		Pid::this()
+	};
+	let child = ChildProc::new(Pid::this(), Some("cd"), Some(child_pgid))?;
+	job.push_child(child);
+
+	let argv = prepare_argv(argv);
+	let new_dir = if let Some((arg,_)) = argv.into_iter().skip(1).next() {
+		PathBuf::from(arg)
+	} else {
+		PathBuf::from(env::var("HOME").unwrap())
+	};
+
+	env::set_current_dir(new_dir).unwrap();
+	let new_dir = env::current_dir().unwrap();
+	env::set_var("PWD", new_dir);
+
+	Ok(())
+}