ddidderr
59bc84fde0
Ports the parts of Ghostty's IO layer that don't depend on the terminal: - pty.zig: pty pair, window size, mode, child-side setsid/TIOCSCTTY; master is CLOEXEC with IUTF8 set - Command.zig: fork/execvpe with Ghostty's exact child setup (stdio dup2, best-effort chdir, rlimit restore, os/runtime pre-exec hooks, cgroup handling) and exit status decoding - shell_integration.zig for bash/zsh/fish/elvish/nushell plus feature flags; scripts copied verbatim to resources/shell-integration/ - terminfo generator for xterm-ghostty, byte-identical to Zig's encode output (golden file produced with the real Zig code) This crate opts into unsafe_code = "deny" (fork/exec need it) with allow + SAFETY comments on minimal items. Integration left: config-derived option types are local stand-ins; cgroup D-Bus scope creation is a closure hook; Exec/Termio/Thread/ stream_handler wait for ghostty-terminal. Pty now closes both fds on drop (Zig never auto-closed the slave) - to re-check when wiring Exec. Test Plan: - cargo test -p ghostty-termio (52 tests, incl. real pty spawn test expecting "hi\r\n31 97\r\n" from `echo hi; stty size`)
73 lines
5.0 KiB
Markdown
73 lines
5.0 KiB
Markdown
# ghostty-termio notes (agent IO1)
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Linux only. Crate lints: `unsafe_code = "deny"` (workspace clippy table copied
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into the crate's `[lints.clippy]`); `#[allow(unsafe_code)]` only on tiny items
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with `// SAFETY:` (fork, execvpe, _exit, close, sigaction, borrow_raw).
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## File -> module
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- `pty.zig` -> `pty.rs` (`Pty`, `Winsize`, `Mode`, `child_pre_exec(master, slave)`)
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- `Command.zig` (+ `apprt/gtk/{pre_exec,post_fork}.zig` cgroup logic, `cgroup.zig` fmtScope)
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-> `command.rs`
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- `termio/shell_integration.zig` -> `shell_integration.rs`
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- `terminfo/{main,Source,ghostty}.zig` -> `terminfo/{mod,source,ghostty}.rs`
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(`terminfo::ghostty` is a `const Source`; `encode`, `encode_to_string`,
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`xtgettcap_map`). Output verified byte-identical with the Zig `encode` (golden
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file `tests/data/xterm-ghostty.terminfo`, generated with `zig run`).
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- Shell scripts copied verbatim to `resources/shell-integration/` (workspace root).
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## Not ported (deferred; need ghostty-terminal / renderer)
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Exec.zig, Termio.zig, Thread.zig, stream_handler.zig, mailbox.zig, message.zig,
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backend.zig, Options.zig (all reference `terminal`/`renderer`/`apprt` types).
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## Design / deviations
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- Deps `ghostty-config` and `ghostty-terminal` REMOVED from Cargo.toml (note in file).
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Deps: ghostty-os, rustix (pty, termios, process, fs, stdio), nix (signal), libc, log, thiserror.
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- `Command` does its own `fork` + `libc::execvpe` (not std::process::Command) so the
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child setup is exactly Ghostty's: dup2 stdio (CLOEXEC cleared), best-effort chdir
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(failure ignored), restore rlimit (`restore_rlimit: Option<Rlimit>` replaces
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`global_state.rlimits`), `os_pre_exec` then `rt_pre_exec` hooks (`Fn() -> Option<u8>`,
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`Some(code)` => `_exit(code)`; panics => exit 1), then execvpe. All allocation happens
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before fork. Exec failure: child prints the same "Requested executable not found" message
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(other errors: `errno=N` instead of the Zig error name) to stderr and `_exit(1)`; there
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is no `ExecFailedInChild` error because the child can never return into caller code.
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`exit_immediately(code)` is provided for hooks that want to exit (use instead of
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`std::process::exit`).
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- Signal mask: Zig never reset the mask explicitly in Command either; only `Pty::child_pre_exec`
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resets 13 signal dispositions to SIG_DFL (same list as Zig), then setsid + TIOCSCTTY and
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closes slave+master. Close-all-fds is not done (Zig doesn't either; master is CLOEXEC).
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- stdio fields are `Option<OwnedFd>` (callers pass `try_clone()`d fds); `wait(block)` returns
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`Result<Exit, Errno>`; non-blocking wait loops until a status is available (as Zig, with a
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`yield_now`). `setData/getData` dropped (closures capture state). Empty `args` => argv =
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[path] (what the Zig doc comment promises; Zig code itself passed an empty argv).
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- Inherited env is snapshotted with `vars_os()` before fork (Zig passes `environ`).
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- `Pty`: `slave: Option<OwnedFd>`; both fds close on drop (Zig never auto-closed the slave).
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Master opened CLOEXEC, slave not (like glibc openpty + explicit CLOEXEC). IUTF8 set.
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- cgroup: `linux_cgroup_pre_exec(&RtPreExecInfo)` (child side, waits <=250ms) and
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`linux_cgroup_post_fork(cmd, &RtPostForkInfo, create_scope)` where `create_scope` is a
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closure standing in for the GIO D-Bus `cgroup.createScope`. `fmt_scope(pid)`.
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Local `LinuxCgroup`/`GtkSingleInstance`/`Rt*Info` types: TODO(integration) from ghostty-config.
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- shell_integration: local `Command` (Shell/Direct) with `ArgIteratorGeneral` quoting rules,
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`ShellIntegrationFeatures` (same defaults) - TODO(integration) replace with config types.
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`EnvMap = HashMap<String,String>`. `setup(resource_dir, &Command, &mut EnvMap, Option<Shell>)`
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-> `Result<Option<ShellIntegration>, Error>` (Error only from `homedir::home`).
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Darwin `/bin/bash` special case dropped.
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## Tests (52 total: 47 unit + 5 integration, all passing)
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Zig tests ported (35): pty 1; Command 10 (createNullDelimitedEnvMap as `prepare()`, os/rt pre exec
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1+2, rt post fork, redirect stdout, custom env, custom cwd, execve failure); shell_integration 21
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(force shell, failure, detectShell, setup features, bash x8, xdg x3, nushell x3, zsh x3);
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terminfo 3 (xtgettcap map, Source encode, ghostty encode).
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Skipped: Windows/NullPty/Windows env block helpers, `refAllDecls` tests.
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Extras: pty cloexec/IUTF8/mode, Exit decoding, signal exit, nonblocking wait, invalid cwd ignored,
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fd leak check, cgroup mode matrices, arg splitter, bundled-resources check, terminfo golden vs Zig,
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`tic -x` compile of the generated source (skipped if tic absent),
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`tests/pty_command.rs`: real `/bin/sh -c 'echo hi; stty size'` on a 31x97 pty (output
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`hi\r\n31 97\r\n`), controlling-tty check, resize check.
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## Known gaps / TODO(integration)
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- Config-derived types above; `restore_rlimit` from global state; D-Bus scope creation.
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- `Pty::child_pre_exec` is meant to be called from Exec's `os_pre_exec` (see tests/pty_command.rs
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for the wiring). Flatpak passwd path in ghostty-os needs Pty (ghostty-os TODO) - now available.
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- Hooks run after fork in a possibly multithreaded process; `linux_cgroup_pre_exec` allocates
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and sleeps (same as Zig) - fine on glibc.
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