Mountain/Environment/Utility/
EnhanceShellEnvironment.rs

1
2//! macOS / Linux GUI launches (Finder double-click, Dock, Spotlight,
3//! `open <bundle>.app`) hand the app a minimal environment:
4//! `PATH=/usr/bin:/bin:/usr/sbin:/sbin`, no `NVM_DIR`, no `HOMEBREW_PREFIX`,
5//! no `JAVA_HOME`, …
6//!
7//! That breaks every child process Mountain or its extensions spawn:
8//! - Cocoon's `node` binary can't find Homebrew installs (`/opt/homebrew/bin`,
9//!   `/usr/local/bin`).
10//! - Language servers (rust-analyzer, gopls, pyright) probe `PATH` and fail to
11//!   launch.
12//! - Git extensions invoking `git` fall back to `/usr/bin/git` (Apple's ancient
13//!   stock copy) instead of the Homebrew one.
14//!
15//! VS Code, Atom, and most other Electron editors solve this by spawning
16//! the user's interactive shell with `-ilc env` once at boot and merging
17//! the result into the process environment. We do the same here.
18//!
19//! Skipped when:
20//! - The launcher is already a TTY (the user invoked from a terminal - PATH is
21//!   already correct).
22//! - `Walk=0` (matches the existing knob users may rely on).
23//! - The shell probe fails or times out (best-effort; never fatal).
24
25use std::time::Duration;
26
27/// Run `$SHELL -ilc env` and merge novel keys into `std::env`. Existing
28/// values win - never clobber an env var the parent process explicitly
29/// set (especially `PATH` if the user passed one). Caller is expected
30/// to invoke this exactly once during boot, before any child process
31/// is spawned.
32pub fn Fn() {
33	// TTY = launched from terminal = already has the user's shell env.
34	if IsTty() {
35		return;
36	}
37
38	let Shell = std::env::var("SHELL").unwrap_or_else(|_| "/bin/zsh".to_string());
39
40	// `-i` (interactive) loads `~/.zshrc` / `~/.bashrc` where users
41	// typically extend PATH. `-l` (login) loads `~/.zprofile` /
42	// `~/.bash_profile` where Homebrew, NVM, and similar set their
43	// roots. `-c env` prints every var the shell knows.
44	let Output = std::process::Command::new(&Shell)
45		.args(["-ilc", "env"])
46		.stdin(std::process::Stdio::null())
47		.stdout(std::process::Stdio::piped())
48		.stderr(std::process::Stdio::null())
49		.spawn();
50
51	let mut Child = match Output {
52		Ok(C) => C,
53
54		Err(_) => return,
55	};
56
57	// Hard cap so a misbehaving rc-file (network call in `.zshrc`,
58	// blocking `read`) doesn't stall boot. 2 s is well above the
59	// observed worst-case shells in the wild.
60	let Deadline = std::time::Instant::now() + Duration::from_secs(2);
61
62	loop {
63		match Child.try_wait() {
64			Ok(Some(_)) => break,
65
66			Ok(None) => {
67				if std::time::Instant::now() >= Deadline {
68					let _ = Child.kill();
69
70					let _ = Child.wait();
71
72					return;
73				}
74
75				std::thread::sleep(Duration::from_millis(20));
76			},
77
78			Err(_) => return,
79		}
80	}
81
82	let StdoutBytes = match Child.wait_with_output() {
83		Ok(O) => O.stdout,
84
85		Err(_) => return,
86	};
87
88	let Text = match String::from_utf8(StdoutBytes) {
89		Ok(S) => S,
90
91		Err(_) => return,
92	};
93
94	for Line in Text.lines() {
95		let Some((Key, Value)) = Line.split_once('=') else { continue };
96
97		let Key = Key.trim();
98
99		if Key.is_empty() || !IsPortableEnvName(Key) {
100			continue;
101		}
102
103		// PATH is special: we only reach this point because IsTty() was
104		// false, meaning the process was launched from Finder/Dock/launchd
105		// with PATH=/usr/bin:/bin:/usr/sbin:/sbin.  That minimal value
106		// is NOT the user's intentional PATH - always let the shell
107		// replace it so git, node, language servers, etc. are all found.
108		// For every other var, preserve any explicit value the user set
109		// (e.g. `FOO=bar open /Applications/X.app`).
110		if Key != "PATH" && std::env::var_os(Key).is_some() {
111			continue;
112		}
113
114		// SAFETY: pre-window, single-threaded boot path. set_var is
115		// safe at this point. Mountain's other modules read env
116		// through `std::env::var` snapshots after this returns.
117		unsafe { std::env::set_var(Key, Value) };
118	}
119}
120
121fn IsTty() -> bool {
122	// `IsTerminal` (stable since Rust 1.70) wraps platform isatty
123	// without pulling in libc. Stdin is the right fd to probe -
124	// Mountain redirects stdout/stderr to its own logger, so those
125	// always look "non-tty" even from a real terminal.
126	use std::io::IsTerminal;
127
128	std::io::stdin().is_terminal()
129}
130
131/// Reject keys with characters outside the portable POSIX set so a
132/// hostile rc-file can't sneak shell metacharacters into our env via a
133/// crafted `Key=` line. Standard env-var names are
134/// `[A-Za-z_][A-Za-z0-9_]*`; anything else is dropped silently.
135fn IsPortableEnvName(Name:&str) -> bool {
136	let mut Chars = Name.chars();
137
138	match Chars.next() {
139		Some(C) if C.is_ascii_alphabetic() || C == '_' => {},
140
141		_ => return false,
142	}
143
144	Chars.all(|C| C.is_ascii_alphanumeric() || C == '_')
145}
Mountain/Environment/Utility/EnhanceShellEnvironment.rs

Mountain/Environment/Utility/
EnhanceShellEnvironment.rs
