Persist sessions across server restarts via per-session holders
Make dosh terminal sessions survive a dosh-server restart (crash/upgrade/systemctl restart): a reattaching client lands on the SAME shell with screen state intact, instead of a fresh one. Design: when persist_sessions is on (new config, default true) each terminal session's shell runs in a small detached per-session holder process (the dosh-server binary re-exec'd as `dosh-server hold`). The holder double-forks + setsid into its own session, opens the PTY, spawns the shell as ITS child, and serves the PTY master fd over a per-session Unix socket via SCM_RIGHTS. The server adopts that fd to build a PtyHandle that DETACHES (does not kill the shell) on drop, so a server exit leaves holder + shell alive. On startup the server scans the runtime dir under sessions_dir/run, reconnects to each live holder, receives the master fd again, restores the persisted vt100 screen, and rebuilds the Session. Screen/scrollback (server-memory only) is mirrored to disk atomically: byte-throttled on the output hot path plus a 2s periodic flush, and restored on re-adoption so reattach repaints. Truly-abandoned persistent sessions are still reaped per the existing grace logic by asking the holder to shut down. Anything in the persistent path failing degrades gracefully to the original in-process shell. PtyHandle gains an Owned (kill-on-drop, unchanged default) vs Adopted (detach-on-drop) backing; resize on an adopted master uses TIOCSWINSZ. No wire-format change, so protocol::VERSION stays 3. New deps: libc (direct). New config: persist_sessions (default true); existing integration tests pin it false to keep exercising the non-persistent path unchanged. Adds tests/integration_smoke.rs::session_survives_server_restart_same_ shell_and_screen: attaches, sets `cd /tmp; export MARK=...`, paints a screen marker, KILLs the server, restarts it on the same config, reattaches and asserts same shell pid + MARK + PWD + restored screen. Plus persist.rs unit tests (name round-trip, screen save/load, dead-holder scan cleanup, SCM_RIGHTS fd round-trip). cargo fmt --check and cargo test green. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
DuProcess
co-authored by
Claude Opus 4.8
Claude Opus 4.8
parent
683c3cd01d
commit
8b1af51bc6
+658
@@ -0,0 +1,658 @@
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//! Session persistence across server restarts.
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//!
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//! A persistent dosh session's shell does not run as a child of `dosh-server`.
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//! Instead the server spawns a tiny per-session *holder* process (the same
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//! `dosh-server` binary re-exec'd as `dosh-server hold ...`). The holder calls
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//! `setsid()` to leave the server's process group/session, opens a PTY, spawns
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//! the shell as ITS own child, and listens on a Unix socket in a per-session
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//! runtime directory. The server connects to that socket and the holder hands it
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//! the PTY master fd over `SCM_RIGHTS`.
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//!
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//! Because the shell belongs to the holder (which is in its own session and is
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//! not waited on by the server), killing or restarting `dosh-server` leaves the
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//! holder + shell alive. On startup the server scans the runtime directory,
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//! reconnects to each live holder, receives the master fd again, and rebuilds the
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//! in-memory session so clients reattach to the very same shell.
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//!
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//! Screen / scrollback state lives only in server memory, so it is also mirrored
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//! to disk (atomically) and restored on re-adoption, letting a reattaching client
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//! repaint the screen exactly as it was before the restart.
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use anyhow::{Context, Result, anyhow, bail};
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use std::io::{Read, Write};
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use std::os::fd::{AsRawFd, FromRawFd, IntoRawFd, RawFd};
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use std::os::unix::net::{UnixListener, UnixStream};
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use std::path::{Path, PathBuf};
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use std::time::Duration;
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/// One-byte commands a server sends to a holder over its control socket after
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/// the holder has handed back the master fd.
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const HOLDER_CMD_SHUTDOWN: u8 = b'X';
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/// Magic written into a holder's `meta` file, bumped if the on-disk layout
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/// changes so a stale holder from an incompatible build is ignored.
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const META_MAGIC: &str = "dosh-holder-1";
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/// Per-session runtime metadata persisted next to the holder socket.
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#[derive(Debug, Clone)]
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pub struct HolderMeta {
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pub session: String,
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pub shell_pid: i32,
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}
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/// Root runtime directory holding one subdirectory per persistent session.
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/// Lives under `sessions_dir/run` so it shares the session storage location and
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/// can be wiped with it.
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pub fn runtime_root(sessions_dir: &Path) -> PathBuf {
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sessions_dir.join("run")
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}
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/// Map a session name to a filesystem-safe directory name. Session names are
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/// user-controlled, so hex-encode them rather than trusting them as path
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/// components (avoids traversal, slashes, NULs, length issues).
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fn session_dir_name(session: &str) -> String {
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let mut out = String::with_capacity(session.len() * 2);
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for byte in session.as_bytes() {
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out.push(char::from_digit((byte >> 4) as u32, 16).unwrap());
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out.push(char::from_digit((byte & 0xf) as u32, 16).unwrap());
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}
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out
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}
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fn decode_session_dir_name(name: &str) -> Option<String> {
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if !name.len().is_multiple_of(2) {
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return None;
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}
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let mut bytes = Vec::with_capacity(name.len() / 2);
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let raw = name.as_bytes();
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let mut i = 0;
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while i < raw.len() {
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let hi = (raw[i] as char).to_digit(16)?;
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let lo = (raw[i + 1] as char).to_digit(16)?;
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bytes.push(((hi << 4) | lo) as u8);
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i += 2;
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}
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String::from_utf8(bytes).ok()
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}
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/// Directory for one session's holder runtime state.
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pub fn session_runtime_dir(sessions_dir: &Path, session: &str) -> PathBuf {
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runtime_root(sessions_dir).join(session_dir_name(session))
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}
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fn holder_sock_path(dir: &Path) -> PathBuf {
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dir.join("holder.sock")
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}
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fn meta_path(dir: &Path) -> PathBuf {
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dir.join("meta")
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}
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fn screen_path(dir: &Path) -> PathBuf {
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dir.join("screen")
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}
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/// Create the runtime directory tree with private (0700) permissions.
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pub fn ensure_runtime_dir(sessions_dir: &Path, session: &str) -> Result<PathBuf> {
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use std::os::unix::fs::PermissionsExt;
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let root = runtime_root(sessions_dir);
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std::fs::create_dir_all(&root).with_context(|| format!("create {}", root.display()))?;
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let _ = std::fs::set_permissions(&root, std::fs::Permissions::from_mode(0o700));
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let dir = session_runtime_dir(sessions_dir, session);
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std::fs::create_dir_all(&dir).with_context(|| format!("create {}", dir.display()))?;
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std::fs::set_permissions(&dir, std::fs::Permissions::from_mode(0o700))
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.with_context(|| format!("chmod {}", dir.display()))?;
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Ok(dir)
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}
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/// Atomically write `data` to `path` (write temp + rename), so a concurrent
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/// reader (e.g. a restarting server) never sees a half-written file.
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fn atomic_write(path: &Path, data: &[u8]) -> Result<()> {
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use std::os::unix::fs::PermissionsExt;
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let tmp = path.with_extension("tmp");
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{
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let mut file =
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std::fs::File::create(&tmp).with_context(|| format!("create {}", tmp.display()))?;
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let _ = file.set_permissions(std::fs::Permissions::from_mode(0o600));
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file.write_all(data)
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.with_context(|| format!("write {}", tmp.display()))?;
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file.sync_all().ok();
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}
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std::fs::rename(&tmp, path)
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.with_context(|| format!("rename {} -> {}", tmp.display(), path.display()))?;
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Ok(())
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}
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/// Persist the vt100 screen snapshot plus recent raw output for a session so a
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/// post-restart reattach repaints correctly. `snapshot` is the bytes a fresh
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/// attach would receive (alt-screen toggle + `state_formatted`).
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pub fn save_screen(
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sessions_dir: &Path,
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session: &str,
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cols: u16,
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rows: u16,
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output_seq: u64,
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snapshot: &[u8],
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) -> Result<()> {
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let dir = session_runtime_dir(sessions_dir, session);
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if !dir.exists() {
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// No holder runtime for this session (non-persistent): nothing to do.
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return Ok(());
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}
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let mut buf = Vec::with_capacity(snapshot.len() + 32);
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buf.extend_from_slice(&cols.to_be_bytes());
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buf.extend_from_slice(&rows.to_be_bytes());
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buf.extend_from_slice(&output_seq.to_be_bytes());
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buf.extend_from_slice(&(snapshot.len() as u32).to_be_bytes());
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buf.extend_from_slice(snapshot);
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atomic_write(&screen_path(&dir), &buf)
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}
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/// A restored screen for a re-adopted session.
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pub struct SavedScreen {
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pub cols: u16,
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pub rows: u16,
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pub output_seq: u64,
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pub snapshot: Vec<u8>,
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}
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/// Load a previously persisted screen, if any.
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pub fn load_screen(sessions_dir: &Path, session: &str) -> Option<SavedScreen> {
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let dir = session_runtime_dir(sessions_dir, session);
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let data = std::fs::read(screen_path(&dir)).ok()?;
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if data.len() < 16 {
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return None;
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}
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let cols = u16::from_be_bytes(data[0..2].try_into().ok()?);
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let rows = u16::from_be_bytes(data[2..4].try_into().ok()?);
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let output_seq = u64::from_be_bytes(data[4..12].try_into().ok()?);
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let len = u32::from_be_bytes(data[12..16].try_into().ok()?) as usize;
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if data.len() < 16 + len {
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return None;
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}
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Some(SavedScreen {
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cols,
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rows,
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output_seq,
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snapshot: data[16..16 + len].to_vec(),
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})
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}
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fn write_meta(dir: &Path, meta: &HolderMeta) -> Result<()> {
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let body = format!("{META_MAGIC}\n{}\n{}\n", meta.shell_pid, meta.session);
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atomic_write(&meta_path(dir), body.as_bytes())
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}
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fn read_meta(dir: &Path) -> Option<HolderMeta> {
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let body = std::fs::read_to_string(meta_path(dir)).ok()?;
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let mut lines = body.lines();
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if lines.next()? != META_MAGIC {
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return None;
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}
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let shell_pid: i32 = lines.next()?.parse().ok()?;
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let session = lines.next()?.to_string();
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Some(HolderMeta { session, shell_pid })
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}
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/// Spawn a holder process for `session`: re-exec this binary as `dosh-server
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/// hold` with the runtime dir, shell, terminal size, and accepted env. The
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/// holder daemonizes (setsid, owns the PTY) and listens on its control socket.
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/// Returns once the holder has signalled readiness by creating its socket.
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#[allow(clippy::too_many_arguments)]
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pub fn spawn_holder(
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sessions_dir: &Path,
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session: &str,
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shell: &str,
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cols: u16,
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rows: u16,
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env: &[(String, String)],
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) -> Result<()> {
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let dir = ensure_runtime_dir(sessions_dir, session)?;
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let sock = holder_sock_path(&dir);
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// Clear any stale socket left by a crashed holder with the same name.
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let _ = std::fs::remove_file(&sock);
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let exe = std::env::current_exe().context("locate current executable")?;
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let mut cmd = std::process::Command::new(exe);
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cmd.arg("hold")
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.arg("--runtime-dir")
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.arg(&dir)
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.arg("--session")
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.arg(session)
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.arg("--shell")
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.arg(shell)
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.arg("--cols")
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.arg(cols.to_string())
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.arg("--rows")
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.arg(rows.to_string());
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for (name, value) in env {
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cmd.arg("--env").arg(format!("{name}={value}"));
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}
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cmd.stdin(std::process::Stdio::null())
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.stdout(std::process::Stdio::null())
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.stderr(std::process::Stdio::null());
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let mut child = cmd.spawn().context("spawn holder process")?;
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// Wait (briefly) for the holder to come up. The holder forks/setsids before
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// creating the socket; once the socket exists we can connect. We also reap
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// the short-lived launcher child so it never becomes a zombie.
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let deadline = std::time::Instant::now() + Duration::from_secs(5);
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loop {
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if sock.exists() {
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break;
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}
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if std::time::Instant::now() >= deadline {
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let _ = child.kill();
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let _ = child.wait();
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bail!("holder for session {session} did not come up in time");
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}
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std::thread::sleep(Duration::from_millis(20));
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}
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// The launcher exits immediately after the grandchild setsids; reap it.
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let _ = child.wait();
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Ok(())
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}
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/// Connect to a session's holder and receive the PTY master fd over SCM_RIGHTS.
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/// Returns the raw fd (caller owns it) and the holder control socket, kept open
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/// so the server can later ask the holder to shut down. Returns an error if the
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/// holder is gone (caller then degrades to a fresh, non-persistent session).
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pub fn adopt_holder(sessions_dir: &Path, session: &str) -> Result<(RawFd, UnixStream)> {
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let dir = session_runtime_dir(sessions_dir, session);
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let sock = holder_sock_path(&dir);
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let mut stream = UnixStream::connect(&sock)
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.with_context(|| format!("connect holder socket {}", sock.display()))?;
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stream.set_read_timeout(Some(Duration::from_secs(5))).ok();
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let fd = recv_fd(&mut stream).context("receive master fd from holder")?;
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Ok((fd, stream))
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}
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/// Ask a holder to terminate its shell and exit, then clean its runtime dir.
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/// Used when reaping a truly-abandoned persistent session.
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pub fn request_shutdown(sessions_dir: &Path, session: &str, control: Option<&mut UnixStream>) {
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if let Some(stream) = control {
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let _ = stream.write_all(&[HOLDER_CMD_SHUTDOWN]);
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let _ = stream.flush();
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} else {
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let dir = session_runtime_dir(sessions_dir, session);
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if let Ok(mut stream) = UnixStream::connect(holder_sock_path(&dir)) {
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// Drain the fd the holder sends on connect, then send shutdown.
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let _ = recv_fd(&mut stream);
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let _ = stream.write_all(&[HOLDER_CMD_SHUTDOWN]);
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let _ = stream.flush();
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}
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}
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// Give the holder a moment to tear down, then remove its runtime dir.
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std::thread::sleep(Duration::from_millis(50));
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let dir = session_runtime_dir(sessions_dir, session);
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let _ = std::fs::remove_dir_all(&dir);
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}
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/// Remove a session's runtime directory unconditionally (best effort).
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pub fn remove_runtime_dir(sessions_dir: &Path, session: &str) {
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let dir = session_runtime_dir(sessions_dir, session);
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let _ = std::fs::remove_dir_all(&dir);
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}
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/// Scan the runtime root for holders left behind by a previous server. Returns
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/// `(session_name, meta)` for each one whose holder process still appears alive.
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/// Stale entries (no live process) are cleaned up.
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pub fn scan_existing_holders(sessions_dir: &Path) -> Vec<HolderMeta> {
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let root = runtime_root(sessions_dir);
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let mut found = Vec::new();
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let Ok(entries) = std::fs::read_dir(&root) else {
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return found;
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};
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for entry in entries.flatten() {
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let dir = entry.path();
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if !dir.is_dir() {
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continue;
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}
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let Some(name) = dir.file_name().and_then(|n| n.to_str()) else {
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continue;
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};
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// Decode the on-disk name back to a session name; skip junk dirs.
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if decode_session_dir_name(name).is_none() {
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continue;
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}
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match read_meta(&dir) {
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Some(meta) if process_alive(meta.shell_pid) && holder_sock_path(&dir).exists() => {
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found.push(meta);
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}
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_ => {
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// Holder gone or meta unreadable: clean up so we don't try to
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// adopt a dead session (degrade to fresh on next attach).
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let _ = std::fs::remove_dir_all(&dir);
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}
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}
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}
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found
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}
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/// Whether a pid refers to a live process (signal 0 probe).
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fn process_alive(pid: i32) -> bool {
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if pid <= 0 {
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return false;
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}
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unsafe {
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libc::kill(pid, 0) == 0
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|| std::io::Error::last_os_error().raw_os_error() == Some(libc::EPERM)
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}
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}
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// ---------------------------------------------------------------------------
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// Holder process entry point
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// ---------------------------------------------------------------------------
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/// Run as a holder process. Daemonizes (double-fork + setsid), opens a PTY,
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/// spawns the shell as its own child, and serves the control socket: every
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/// accepted connection is handed the master fd (SCM_RIGHTS); a subsequent
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/// SHUTDOWN byte (or the shell exiting) tears everything down.
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///
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/// This function does not return on success — it `exit`s the process. Errors
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/// before the daemonization point are returned to the launcher.
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#[allow(clippy::too_many_arguments)]
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pub fn run_holder(
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runtime_dir: &Path,
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session: &str,
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shell: &str,
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cols: u16,
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rows: u16,
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env: &[(String, String)],
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) -> Result<()> {
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use portable_pty::{NativePtySystem, PtySize, PtySystem};
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// Detach from the launching server: own session + process group so a server
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// exit (even a process-group kill of the service) does not take us down.
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daemonize().context("daemonize holder")?;
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let pty_system = NativePtySystem::default();
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let pair = pty_system
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.openpty(PtySize {
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rows,
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cols,
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pixel_width: 0,
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pixel_height: 0,
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})
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.context("holder open pty")?;
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let cmd = crate::pty::build_shell_command(shell, env);
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let mut child = pair
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.slave
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.spawn_command(cmd)
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.context("holder spawn shell")?;
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drop(pair.slave);
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let master_fd = pair
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.master
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.as_raw_fd()
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.ok_or_else(|| anyhow!("holder master has no raw fd"))?;
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let shell_pid = child.process_id().map(|p| p as i32).unwrap_or(-1);
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write_meta(
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runtime_dir,
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&HolderMeta {
|
||||
session: session.to_string(),
|
||||
shell_pid,
|
||||
},
|
||||
)?;
|
||||
|
||||
let sock = holder_sock_path(runtime_dir);
|
||||
let _ = std::fs::remove_file(&sock);
|
||||
let listener =
|
||||
UnixListener::bind(&sock).with_context(|| format!("holder bind {}", sock.display()))?;
|
||||
{
|
||||
use std::os::unix::fs::PermissionsExt;
|
||||
let _ = std::fs::set_permissions(&sock, std::fs::Permissions::from_mode(0o600));
|
||||
}
|
||||
listener
|
||||
.set_nonblocking(false)
|
||||
.context("holder listener blocking")?;
|
||||
|
||||
// A watcher thread reaps the shell: when it exits, the holder cleans up and
|
||||
// exits too, so an abandoned shell does not linger forever.
|
||||
let runtime_owned = runtime_dir.to_path_buf();
|
||||
std::thread::spawn(move || {
|
||||
let _ = child.wait();
|
||||
// Shell exited: remove runtime dir and exit the holder process.
|
||||
let _ = std::fs::remove_dir_all(&runtime_owned);
|
||||
std::process::exit(0);
|
||||
});
|
||||
|
||||
// Accept loop: each connecting server gets the master fd; a SHUTDOWN byte
|
||||
// from any of them tears the holder down. Multiple servers never run at once
|
||||
// in practice (one service), but serving repeated connections lets a server
|
||||
// restart re-adopt cleanly.
|
||||
for stream in listener.incoming() {
|
||||
let Ok(mut stream) = stream else { continue };
|
||||
if send_fd(&mut stream, master_fd).is_err() {
|
||||
continue;
|
||||
}
|
||||
// Wait for an optional command byte. EOF (server dropped the control
|
||||
// socket on its own exit) just means "keep running, await re-adoption".
|
||||
let mut cmd = [0u8; 1];
|
||||
match stream.read(&mut cmd) {
|
||||
Ok(1) if cmd[0] == HOLDER_CMD_SHUTDOWN => {
|
||||
let _ = std::fs::remove_dir_all(runtime_dir);
|
||||
std::process::exit(0);
|
||||
}
|
||||
_ => {
|
||||
// Server detached (exit/restart) or sent nothing actionable:
|
||||
// loop back and wait for the next server to re-adopt us.
|
||||
}
|
||||
}
|
||||
}
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Double-fork + `setsid` so the holder runs in its own session, detached from
|
||||
/// the server's controlling terminal and process group. Without this a
|
||||
/// `systemctl restart` (which signals the whole service cgroup/process group)
|
||||
/// could take the holder down with the server.
|
||||
fn daemonize() -> Result<()> {
|
||||
// First fork: parent (launcher) returns to reap; child continues.
|
||||
match unsafe { libc::fork() } {
|
||||
-1 => bail!("fork: {}", std::io::Error::last_os_error()),
|
||||
0 => {}
|
||||
_ => {
|
||||
// Parent process: exit so the launcher's wait() returns promptly and
|
||||
// the grandchild is reparented to init.
|
||||
std::process::exit(0);
|
||||
}
|
||||
}
|
||||
// New session: detaches from controlling tty and the server's process group.
|
||||
if unsafe { libc::setsid() } == -1 {
|
||||
bail!("setsid: {}", std::io::Error::last_os_error());
|
||||
}
|
||||
// Second fork: ensures we are not a session leader, so we can never
|
||||
// re-acquire a controlling terminal.
|
||||
match unsafe { libc::fork() } {
|
||||
-1 => bail!("fork2: {}", std::io::Error::last_os_error()),
|
||||
0 => Ok(()),
|
||||
_ => std::process::exit(0),
|
||||
}
|
||||
}
|
||||
|
||||
// ---------------------------------------------------------------------------
|
||||
// SCM_RIGHTS file-descriptor passing over a Unix domain socket
|
||||
// ---------------------------------------------------------------------------
|
||||
|
||||
/// Send a single fd over `stream` using SCM_RIGHTS, with one byte of normal data
|
||||
/// (sendmsg requires at least one iovec byte for the ancillary data to ride on).
|
||||
fn send_fd(stream: &mut UnixStream, fd: RawFd) -> Result<()> {
|
||||
let dummy: [u8; 1] = [0];
|
||||
let mut iov = libc::iovec {
|
||||
iov_base: dummy.as_ptr() as *mut libc::c_void,
|
||||
iov_len: 1,
|
||||
};
|
||||
let mut cmsg_buf = [0u8; cmsg_space_one_fd()];
|
||||
let mut msg: libc::msghdr = unsafe { std::mem::zeroed() };
|
||||
msg.msg_iov = &mut iov;
|
||||
msg.msg_iovlen = 1;
|
||||
msg.msg_control = cmsg_buf.as_mut_ptr() as *mut libc::c_void;
|
||||
msg.msg_controllen = cmsg_buf.len() as _;
|
||||
|
||||
unsafe {
|
||||
let cmsg = libc::CMSG_FIRSTHDR(&msg);
|
||||
if cmsg.is_null() {
|
||||
bail!("CMSG_FIRSTHDR null");
|
||||
}
|
||||
(*cmsg).cmsg_level = libc::SOL_SOCKET;
|
||||
(*cmsg).cmsg_type = libc::SCM_RIGHTS;
|
||||
(*cmsg).cmsg_len = libc::CMSG_LEN(std::mem::size_of::<RawFd>() as u32) as _;
|
||||
std::ptr::copy_nonoverlapping(
|
||||
&fd as *const RawFd as *const u8,
|
||||
libc::CMSG_DATA(cmsg),
|
||||
std::mem::size_of::<RawFd>(),
|
||||
);
|
||||
let n = libc::sendmsg(stream.as_raw_fd(), &msg, 0);
|
||||
if n < 0 {
|
||||
return Err(std::io::Error::last_os_error()).context("sendmsg SCM_RIGHTS");
|
||||
}
|
||||
}
|
||||
Ok(())
|
||||
}
|
||||
|
||||
/// Receive a single fd sent via SCM_RIGHTS. Returns a fresh fd owned by the
|
||||
/// caller.
|
||||
fn recv_fd(stream: &mut UnixStream) -> Result<RawFd> {
|
||||
let mut dummy = [0u8; 1];
|
||||
let mut iov = libc::iovec {
|
||||
iov_base: dummy.as_mut_ptr() as *mut libc::c_void,
|
||||
iov_len: 1,
|
||||
};
|
||||
let mut cmsg_buf = [0u8; cmsg_space_one_fd()];
|
||||
let mut msg: libc::msghdr = unsafe { std::mem::zeroed() };
|
||||
msg.msg_iov = &mut iov;
|
||||
msg.msg_iovlen = 1;
|
||||
msg.msg_control = cmsg_buf.as_mut_ptr() as *mut libc::c_void;
|
||||
msg.msg_controllen = cmsg_buf.len() as _;
|
||||
|
||||
unsafe {
|
||||
let n = libc::recvmsg(stream.as_raw_fd(), &mut msg, 0);
|
||||
if n < 0 {
|
||||
return Err(std::io::Error::last_os_error()).context("recvmsg SCM_RIGHTS");
|
||||
}
|
||||
if n == 0 {
|
||||
bail!("holder closed connection before sending fd");
|
||||
}
|
||||
let cmsg = libc::CMSG_FIRSTHDR(&msg);
|
||||
if cmsg.is_null() {
|
||||
bail!("no ancillary data (fd) received from holder");
|
||||
}
|
||||
if (*cmsg).cmsg_level != libc::SOL_SOCKET || (*cmsg).cmsg_type != libc::SCM_RIGHTS {
|
||||
bail!("unexpected ancillary message from holder");
|
||||
}
|
||||
let mut fd: RawFd = -1;
|
||||
std::ptr::copy_nonoverlapping(
|
||||
libc::CMSG_DATA(cmsg),
|
||||
&mut fd as *mut RawFd as *mut u8,
|
||||
std::mem::size_of::<RawFd>(),
|
||||
);
|
||||
if fd < 0 {
|
||||
bail!("invalid fd received from holder");
|
||||
}
|
||||
Ok(fd)
|
||||
}
|
||||
}
|
||||
|
||||
/// Space, in bytes, needed for a control-message buffer carrying exactly one fd.
|
||||
const fn cmsg_space_one_fd() -> usize {
|
||||
// CMSG_SPACE is not const in libc; this is the equivalent for one RawFd.
|
||||
// cmsghdr is aligned to size_of::<usize>(); add data length rounded up.
|
||||
let data = std::mem::size_of::<RawFd>();
|
||||
let hdr = std::mem::size_of::<libc::cmsghdr>();
|
||||
let align = std::mem::size_of::<usize>();
|
||||
// round(hdr) + round(data)
|
||||
((hdr + align - 1) & !(align - 1)) + ((data + align - 1) & !(align - 1))
|
||||
}
|
||||
|
||||
/// Helper used by `adopt_holder` callers to turn the received raw fd into an
|
||||
/// owned `File`-like object if they need RAII (the server hands it to
|
||||
/// `pty::adopt_pty_from_fd`, which takes ownership of the raw fd).
|
||||
pub fn fd_into_file(fd: RawFd) -> std::fs::File {
|
||||
unsafe { std::fs::File::from_raw_fd(fd) }
|
||||
}
|
||||
|
||||
/// Convert a `File` back into a raw fd it no longer owns (so it can be handed to
|
||||
/// `adopt_pty_from_fd`). Currently unused outside tests but kept symmetric.
|
||||
pub fn file_into_fd(file: std::fs::File) -> RawFd {
|
||||
file.into_raw_fd()
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
|
||||
#[test]
|
||||
fn session_dir_name_round_trips() {
|
||||
for name in ["default", "work", "a/b/../c", "weird name", "日本語"] {
|
||||
let encoded = session_dir_name(name);
|
||||
assert!(encoded.bytes().all(|b| b.is_ascii_hexdigit()));
|
||||
assert_eq!(decode_session_dir_name(&encoded).as_deref(), Some(name));
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn decode_rejects_non_hex() {
|
||||
assert!(decode_session_dir_name("zz").is_none());
|
||||
assert!(decode_session_dir_name("abc").is_none());
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn save_and_load_screen_round_trips() {
|
||||
let tmp = tempfile::tempdir().unwrap();
|
||||
let sessions_dir = tmp.path();
|
||||
ensure_runtime_dir(sessions_dir, "work").unwrap();
|
||||
let snap = b"\x1b[?1049lhello world".to_vec();
|
||||
save_screen(sessions_dir, "work", 100, 40, 7, &snap).unwrap();
|
||||
let loaded = load_screen(sessions_dir, "work").expect("screen restored");
|
||||
assert_eq!(loaded.cols, 100);
|
||||
assert_eq!(loaded.rows, 40);
|
||||
assert_eq!(loaded.output_seq, 7);
|
||||
assert_eq!(loaded.snapshot, snap);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn load_screen_absent_is_none() {
|
||||
let tmp = tempfile::tempdir().unwrap();
|
||||
assert!(load_screen(tmp.path(), "missing").is_none());
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn scan_skips_dead_and_junk_entries() {
|
||||
let tmp = tempfile::tempdir().unwrap();
|
||||
let sessions_dir = tmp.path();
|
||||
// A meta pointing at a definitely-dead pid is cleaned up, not returned.
|
||||
let dir = ensure_runtime_dir(sessions_dir, "ghost").unwrap();
|
||||
write_meta(
|
||||
&dir,
|
||||
&HolderMeta {
|
||||
session: "ghost".to_string(),
|
||||
shell_pid: 2_000_000_000, // not a live pid
|
||||
},
|
||||
)
|
||||
.unwrap();
|
||||
// A junk (non-hex) directory is ignored.
|
||||
std::fs::create_dir_all(runtime_root(sessions_dir).join("not-hex")).unwrap();
|
||||
let found = scan_existing_holders(sessions_dir);
|
||||
assert!(found.is_empty(), "dead/junk holders must be skipped");
|
||||
assert!(!dir.exists(), "dead holder dir should be cleaned up");
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn send_and_recv_fd_round_trips() {
|
||||
use std::io::Seek;
|
||||
// Pass a temp file's fd across a socketpair and confirm both ends point
|
||||
// at the same open file (write via one, read via the other).
|
||||
let (mut a, mut b) = UnixStream::pair().unwrap();
|
||||
let mut file = tempfile::tempfile().unwrap();
|
||||
writeln!(file, "shared-fd-marker").unwrap();
|
||||
file.flush().unwrap();
|
||||
send_fd(&mut a, file.as_raw_fd()).unwrap();
|
||||
let received = recv_fd(&mut b).unwrap();
|
||||
let mut got = fd_into_file(received);
|
||||
got.rewind().unwrap();
|
||||
let mut contents = String::new();
|
||||
got.read_to_string(&mut contents).unwrap();
|
||||
assert!(contents.contains("shared-fd-marker"));
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user