yash_cli/
lib.rs

1// This file is part of yash, an extended POSIX shell.
2// Copyright (C) 2021 WATANABE Yuki
3//
4// This program is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// This program is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with this program.  If not, see <https://www.gnu.org/licenses/>.
16
17//! This is an internal library crate for the yash shell. Currently, **this
18//! crate is not intended to be used as a library by other crates. No part of
19//! this crate is covered by semantic versioning.**
20//!
21//! The entry point for the shell is the [`main`] function, which is to be used
22//! as the `main` function in the binary crate. The function sets up the shell
23//! environment and runs the main read-eval loop.
24
25pub mod startup;
26// mod runner;
27
28use self::startup::args::Parse;
29use self::startup::init_file::run_rcfile;
30use self::startup::input::prepare_input;
31use std::cell::RefCell;
32use std::ops::ControlFlow::{Break, Continue};
33use std::rc::Rc;
34use yash_env::Env;
35use yash_env::RealSystem;
36use yash_env::option::{Interactive, On};
37use yash_env::semantics::{Divert, ExitStatus, exit_or_raise};
38use yash_env::system::concurrency::WriteAll;
39use yash_env::system::resource::GetRlimit;
40use yash_env::system::{
41    Chdir, Concurrent, Disposition, Errno, GetCwd, GetUid, Isatty, Sigaction as _, Signals as _,
42    Sysconf, TcGetPgrp, Times, Umask, Write,
43};
44use yash_semantics::trap::run_exit_trap;
45use yash_semantics::{Runtime, interactive_read_eval_loop, read_eval_loop};
46
47async fn print_version<S>(env: &mut Env<S>)
48where
49    S: Isatty + WriteAll,
50{
51    let version = env!("CARGO_PKG_VERSION");
52    let result = yash_builtin::common::output(env, &format!("yash {version}\n")).await;
53    env.exit_status = result.exit_status();
54}
55
56#[allow(
57    clippy::await_holding_refcell_ref,
58    reason = "`print_error` does not run concurrently with the input decorators or read-eval loop"
59)]
60async fn run_as_shell_process<S>(env: &mut Env<S>)
61where
62    S: Chdir
63        + Clone
64        + GetCwd
65        + GetRlimit
66        + GetUid
67        + Runtime
68        + Sysconf
69        + TcGetPgrp
70        + Times
71        + Umask
72        + Write
73        + 'static,
74{
75    // Parse the command-line arguments
76    let run = match self::startup::args::parse(std::env::args()) {
77        Ok(Parse::Help) => todo!("print help"),
78        Ok(Parse::Version) => return print_version(env).await,
79        Ok(Parse::Run(run)) => run,
80        Err(e) => {
81            let arg0 = std::env::args().next().unwrap_or_else(|| "yash".to_owned());
82            env.system.print_error(&format!("{arg0}: {e}\n")).await;
83            env.exit_status = ExitStatus::ERROR;
84            return;
85        }
86    };
87
88    // Import environment variables
89    env.variables.extend_env(std::env::vars());
90
91    let work = self::startup::configure_environment(env, run).await;
92
93    let is_interactive = env.options.get(Interactive) == On;
94
95    // Run initialization files
96    // TODO run profile if login
97    run_rcfile(env, work.rcfile).await;
98
99    // Prepare the input for the main read-eval loop
100    let ref_env = RefCell::new(env);
101    let lexer = match prepare_input(&ref_env, &work.source).await {
102        Ok(lexer) => lexer,
103        Err(e) => {
104            let arg0 = std::env::args().next().unwrap_or_else(|| "yash".to_owned());
105            let message = format!("{arg0}: {e}\n");
106            // The borrow checker of Rust 1.79.0 is not smart enough to reason
107            // about the lifetime of `e` here, so we re-borrow from `ref_env`
108            // instead of taking `env` out of `ref_env`.
109            // let mut env = ref_env.into_inner();
110            let mut env = ref_env.borrow_mut();
111            env.system.print_error(&message).await;
112            env.exit_status = match e.errno {
113                Errno::ENOENT | Errno::ENOTDIR | Errno::EILSEQ => ExitStatus::NOT_FOUND,
114                _ => ExitStatus::NOEXEC,
115            };
116            return;
117        }
118    };
119
120    // Run the read-eval loop
121    let result = if is_interactive {
122        interactive_read_eval_loop(&ref_env, &mut { lexer }).await
123    } else {
124        read_eval_loop(&ref_env, &mut { lexer }).await
125    };
126
127    let env = ref_env.into_inner();
128    env.apply_result(result);
129
130    match result {
131        Continue(())
132        | Break(Divert::Continue { .. })
133        | Break(Divert::Break { .. })
134        | Break(Divert::Return(_))
135        | Break(Divert::Interrupt(_))
136        | Break(Divert::Exit(_)) => run_exit_trap(env).await,
137        Break(Divert::Abort(_)) => (),
138    }
139}
140
141pub fn main() -> ! {
142    // SAFETY: This is the only instance of RealSystem we create in the whole
143    // process.
144    let system = unsafe { RealSystem::new() };
145
146    // Rust by default sets SIGPIPE to SIG_IGN, which is not desired.
147    // As an imperfect workaround, we set SIGPIPE to SIG_DFL here.
148    // TODO Use unix_sigpipe: https://github.com/rust-lang/rust/issues/97889
149    system
150        .sigaction(RealSystem::SIGPIPE, Disposition::Default)
151        .ok();
152
153    let system = Rc::new(Concurrent::new(system));
154    let runner = Rc::clone(&system);
155    let task = async {
156        let mut env = Env::with_system(system);
157        run_as_shell_process(&mut env).await;
158        exit_or_raise(&env.system, env.exit_status).await
159    };
160    runner.run_real(task)
161}
yash_cli/lib.rs

yash_cli/
lib.rs
