iris/ai-app
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Prune commentary and stale Rust port notes

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iris committed 2026-09-10 00:44:13 -04:00
1 parent 5428cd75c9
commit 25370731d0
193 files changed
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server/src/ssh.rs
-109
View File
@@ -1,48 +1,24 @@
//! Building the command a driver actually spawns -- locally, or wrapped in
//! `ssh` when the session names a host to run on.
//!
//! A driver speaks JSONL over a child process's stdio and doesn't care what
//! that child is, so a remote session is the identical command with `ssh host …`
//! in front.
//!
//! Uses the system `ssh` client rather than a Rust SSH library, so
//! `~/.ssh/config`, agents and jump hosts all keep working and there is only
//! one place to configure connections.
use std::path::{Path, PathBuf};
use std::process::Command;
use crate::config::SshConfig;
/// A port on the machine a command runs on, and the port that reaches it from
/// the backend.
///
/// The second half of what a transport is (PLAN.md's SSH section): "run this"
/// plus "reach this port". Locally the two numbers are one and nothing is
/// forwarded; over ssh the connection carries an `-L` tunnel, so a model server
/// binds loopback on the far machine and is never exposed to its network.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Forward {
/// What the launched program should listen on, on its own machine.
pub there: u16,
/// What this machine connects to. The same number as `there` when the
/// program runs here.
pub here: u16,
}
/// Options forced onto every connection. `BatchMode` makes a missing key fail
/// immediately with a readable message instead of hanging on a password prompt
/// nothing can answer; the keepalives turn a silently dropped link into a
/// process exit, which the session reports as `exited` rather than hanging.
const SSH_OPTIONS: [&str; 3] = [
"BatchMode=yes",
"ServerAliveInterval=30",
"ServerAliveCountMax=3",
];
/// Builds the child process for `program args…`, run in `cwd`, either on this
/// machine (`ssh` absent) or on the machine it describes.
///
/// Stdio is left alone: how the streams are connected is the caller's decision
/// and differs by more than the transport does -- a probe wants pipes it will
/// drain, a session wants files that outlive this server.
@@ -61,11 +37,6 @@ pub fn command(
let mut command = Command::new(program);
command.args(args);
if let Some(cwd) = cwd {
// Expanded here for the same reason `quote_path` expands it on the
// far side: a working directory typed as `~/repos/ai-app` has to
// mean the same thing whichever machine runs it. There is no shell
// in this branch, so nothing else would -- `current_dir` would be
// handed the literal one-character directory `~`.
command.current_dir(expand_home(cwd));
}
return command;
@@ -73,17 +44,7 @@ pub fn command(
let mut command = Command::new("ssh");
if let Some(forward) = forward {
// A forwarded process is not spoken to over stdio, and that changes how
// it is shut down. Everything else here is a CLI reading its stdin, so
// killing the ssh client ends it; a `llama-server` never reads its own,
// so the same kill left it running on the far machine with the model
// loaded -- measured 2026-09-04, an orphan per stopped session. A pty
// is what makes sshd hang the far side up. `-tt` because this client
// has no terminal to inherit one from. The cost is a log that arrives
// through a line discipline, which nothing parses.
command.arg("-tt");
// Loopback at both ends: the far side binds 127.0.0.1, so what it
// serves is reachable only through this connection.
command.args([
"-L",
&format!("127.0.0.1:{}:127.0.0.1:{}", forward.here, forward.there),
@@ -93,8 +54,6 @@ pub fn command(
// arrive as "the model never became ready".
command.args(["-o", "ExitOnForwardFailure=yes"]);
} else {
// -T: no pty. This carries JSONL, and a pty would rewrite it (echo,
// CRLF translation, ^C handling) into something the parser can't read.
command.arg("-T");
}
for option in SSH_OPTIONS {
@@ -108,8 +67,6 @@ pub fn command(
}
if let Some(identity) = &ssh.identity_file {
command.arg("-i").arg(identity);
// Without this, ssh may offer an agent key first and authenticate as
// somebody else entirely -- silently, and with different permissions.
command.args(["-o", "IdentitiesOnly=yes"]);
}
command.arg(&ssh.address);
@@ -117,10 +74,6 @@ pub fn command(
command
}
/// The single argument handed to the remote login shell. `exec` so the CLI
/// replaces that shell: the process the connection is attached to is then the
/// CLI itself, and dropping the connection takes it down rather than leaving an
/// orphan behind a live wrapper.
fn remote_script(program: &str, args: &[String], cwd: Option<&Path>) -> String {
let mut script = String::new();
if let Some(cwd) = cwd {
@@ -137,12 +90,6 @@ fn remote_script(program: &str, args: &[String], cwd: Option<&Path>) -> String {
script
}
/// A path with a leading `~` replaced by this machine's home directory.
///
/// The local half of the rule [`quote_path`] states for the remote one, and
/// deliberately the same shape: the tilde is expanded, `~user` is not, and
/// nothing else in the path gains a meaning. A machine with no home directory
/// leaves the path alone, which fails with the operating system's own message.
pub(crate) fn expand_home(path: &Path) -> PathBuf {
let Some(rest) = path.to_str().and_then(|p| {
if p == "~" {
@@ -159,22 +106,11 @@ pub(crate) fn expand_home(path: &Path) -> PathBuf {
}
}
/// Quotes a path, expanding a leading `~` and nothing else.
///
/// [`quote`] is right for every other word crossing to the remote side and
/// wrong for exactly one character. `~` means "expand me", and single quotes
/// are what stop expansion -- so a working directory typed as `~/repos/ai-app`
/// arrived as the literal four-character directory `~`, and the remote shell
/// said it did not exist, which reads like the path being wrong.
///
/// `"$HOME"` rather than handing the tilde to the shell unquoted: the variable
/// is expanded, the expansion is not re-split or globbed because it is
/// double-quoted, and everything after it stays single-quoted and literal.
/// `$HOME` is set by every shell this can land in, including the fish login
/// shell on the dev VM, so this does not depend on the remote shell being POSIX.
///
/// `~user` is deliberately not handled: there is no portable expansion for it,
/// and inventing one would mean guessing another account's home directory.
pub(crate) fn quote_path(path: &str) -> String {
if path == "~" {
return "\"$HOME\"".to_string();
@@ -185,13 +121,7 @@ pub(crate) fn quote_path(path: &str) -> String {
}
}
/// Single-quotes one word for a POSIX shell. Everything crossing to the remote
/// side goes through here: paths, model names and prompts-as-arguments are all
/// attacker-adjacent input in a server whose whole job is running commands, and
/// unquoted they would be shell syntax rather than data.
pub(crate) fn quote(word: &str) -> String {
// Inside single quotes every character is literal except `'` itself, which
// is closed, escaped, and reopened.
format!("'{}'", word.replace('\'', r"'\''"))
}
@@ -203,7 +133,6 @@ mod tests {
args.iter().map(|arg| arg.to_string()).collect()
}
/// The rendered argv, for asserting on what would actually run.
fn argv(command: &Command) -> Vec<String> {
std::iter::once(command.get_program())
.chain(command.get_args())
@@ -211,9 +140,6 @@ mod tests {
.collect()
}
/// A host with nothing configured but a name to dial, so `~/.ssh/config`
/// decides everything else -- the case that proves this adds no flags of its
/// own when it was not told to.
fn bare_host() -> SshConfig {
SshConfig {
address: "vm".to_string(),
@@ -263,7 +189,6 @@ mod tests {
assert!(rendered.contains(&"IdentitiesOnly=yes".to_string()));
assert!(rendered.contains(&"2222".to_string()));
assert!(rendered.contains(&"/home/me/.ssh/id_ai".to_string()));
// The host, then exactly one argument: the remote script.
assert_eq!(rendered[rendered.len() - 2], "bob@10.0.2.15");
assert_eq!(
rendered[rendered.len() - 1],
@@ -276,17 +201,9 @@ mod tests {
let ssh = bare_host();
let rendered = argv(&command(Some(&ssh), "claude", &args(["-p"]), None, None));
assert_eq!(rendered.last().unwrap(), "exec 'claude' '-p'");
// No -i means no IdentitiesOnly: ~/.ssh/config decides instead.
assert!(!rendered.contains(&"IdentitiesOnly=yes".to_string()));
}
/// The second half of a transport: the connection that runs the command also
/// carries the port that reaches it.
///
/// Both ends are pinned to loopback, which is what keeps a model server off
/// the far machine's network -- asserted rather than trusted, because
/// dropping the addresses is a one-word edit that still works on a machine
/// nobody else can reach.
#[test]
fn a_forwarded_port_rides_the_same_connection_as_the_command() {
let ssh = bare_host();
@@ -306,53 +223,33 @@ mod tests {
.expect("a forward");
assert_eq!(rendered[forward + 1], "127.0.0.1:41000:127.0.0.1:24242");
assert!(rendered.contains(&"ExitOnForwardFailure=yes".to_string()));
// The half that is easy to lose: without a pty the far process outlives
// the connection, because nothing closes a stdin it never reads.
assert!(rendered.contains(&"-tt".to_string()));
assert!(!rendered.contains(&"-T".to_string()));
// Options come before the host, or ssh reads them as part of the
// remote command.
assert!(forward < rendered.len() - 2);
assert_eq!(
rendered.last().unwrap(),
"exec 'llama-server' '--port' '24242'"
);
// Nothing forwarded is nothing added: every other session is one of
// these, and an -L on it would bind a port for no reason.
let plain = argv(&command(Some(&ssh), "claude", &args(["-p"]), None, None));
assert!(!plain.contains(&"-L".to_string()));
// And a session that *is* spoken to over stdio keeps its raw pipe.
assert!(plain.contains(&"-T".to_string()));
assert!(!plain.contains(&"-tt".to_string()));
}
/// The one character quoting must not swallow. A working directory typed as
/// `~/repos/ai-app` was arriving as the literal directory `~`, and the
/// remote shell reported it missing -- which reads as the path being wrong
/// rather than the quoting being wrong, and cost an evening.
#[test]
fn a_leading_tilde_expands_and_nothing_else_does() {
assert_eq!(quote_path("~"), "\"$HOME\"");
assert_eq!(quote_path("~/repos/ai-app"), "\"$HOME\"/'repos/ai-app'");
// Only leading, and only its own segment: a tilde anywhere else is an
// ordinary character in a filename, and `~user` has no portable
// expansion so it stays literal.
assert_eq!(quote_path("/tmp/~/x"), "'/tmp/~/x'");
assert_eq!(quote_path("~user/x"), "'~user/x'");
// And it reaches the script the remote shell is handed.
assert_eq!(
remote_script("claude", &args(["-p"]), Some(Path::new("~/repos/ai-app"))),
"cd \"$HOME\"/'repos/ai-app' && exec 'claude' '-p'",
);
}
/// The same character, on the transport with no shell to expand it. The
/// local branch runs the program directly, so a working directory of
/// `~/repos/ai-app` would reach `current_dir` as the literal one-character
/// directory `~`. The two transports have to agree about what a tilde means
/// or a path is only portable by accident.
#[test]
fn a_local_cwd_expands_its_tilde_the_same_way() {
let Some(home) = std::env::home_dir() else {
@@ -363,7 +260,6 @@ mod tests {
home.join("repos/ai-app")
);
assert_eq!(expand_home(Path::new("~")), home);
// Leading only, and its own segment only -- `quote_path`'s rule.
assert_eq!(expand_home(Path::new("/tmp/~/x")), Path::new("/tmp/~/x"));
assert_eq!(expand_home(Path::new("~user/x")), Path::new("~user/x"));
@@ -379,9 +275,6 @@ mod tests {
#[test]
fn shell_metacharacters_cross_as_data_not_syntax() {
// Expanding $HOME must not open a door for anything else: the rest stays
// single-quoted, so this remains one absurd path rather than three
// commands.
assert_eq!(
quote_path("~/'; touch /tmp/pwned; '"),
r#""$HOME"/''\''; touch /tmp/pwned; '\'''"#,
@@ -393,8 +286,6 @@ mod tests {
assert_eq!(quote("$(whoami)"), "'$(whoami)'");
assert_eq!(quote("it's"), r"'it'\''s'");
// The end-to-end version of the same worry: a working directory that
// tries to close the quote and start a new command.
let ssh = bare_host();
let evil = Path::new("/tmp/'; touch /tmp/pwned; '");
let rendered = argv(&command(Some(&ssh), "claude", &[], Some(evil), None));