agentmux_srv/backend/
host_os.rs

1// Copyright 2026, AgentMux Corp.
2// SPDX-License-Identifier: Apache-2.0
3
4//! The operating system an instance runs on, as the Swarm shows it next to a
5//! remote machine (docs/specs/SPEC_SWARM_REMOTE_AGENTS_PLATFORM_TAG_AND_SELECTION_2026_10_03.md §3).
6//!
7//! It is one lowercase string, `std::env::consts::OS` (`windows`, `macos`,
8//! `linux`, ...), advertised by each instance in its LAN record. A peer's value
9//! is self-reported and used for display only, so what arrives from the network
10//! is accepted only in the plain shape below and is never read for a decision.
11
12/// The longest value accepted from a peer.
13pub const MAX_OS_LEN: usize = 16;
14
15/// This instance's own value.
16pub fn local_os() -> String {
17    std::env::consts::OS.to_string()
18}
19
20/// A peer's value, or `None` if it isn't a plain lowercase token. Anything else
21/// (empty, long, upper case, spaces, markup) is dropped, so the frontend never
22/// receives text it didn't expect.
23pub fn sanitize_os(raw: &str) -> Option<String> {
24    let ok = !raw.is_empty()
25        && raw.len() <= MAX_OS_LEN
26        && raw
27            .bytes()
28            .all(|b| b.is_ascii_lowercase() || b.is_ascii_digit() || b == b'_' || b == b'-');
29    ok.then(|| raw.to_string())
30}
31
32#[cfg(test)]
33mod tests {
34    use super::*;
35
36    #[test]
37    fn the_three_platforms_pass_unchanged() {
38        for os in ["windows", "macos", "linux"] {
39            assert_eq!(sanitize_os(os).as_deref(), Some(os));
40        }
41    }
42
43    #[test]
44    fn anything_that_is_not_a_plain_lowercase_token_is_dropped() {
45        assert_eq!(sanitize_os(""), None);
46        assert_eq!(sanitize_os("Windows"), None);
47        assert_eq!(sanitize_os("win dows"), None);
48        assert_eq!(sanitize_os("<b>linux</b>"), None);
49        assert_eq!(sanitize_os("linux\n"), None);
50        assert_eq!(sanitize_os("../etc"), None);
51        assert_eq!(sanitize_os(&"a".repeat(MAX_OS_LEN + 1)), None);
52        assert_eq!(sanitize_os(&"a".repeat(MAX_OS_LEN)).as_deref(), Some("a".repeat(MAX_OS_LEN).as_str()));
53    }
54
55    #[test]
56    fn this_instance_advertises_a_value_it_would_itself_accept() {
57        assert!(sanitize_os(&local_os()).is_some());
58    }
59}
agentmux_srv/backend/host_os.rs

agentmux_srv/backend/
host_os.rs
