implement sh

Cargo.toml

@@ -20,6 +20,7 @@ members = [
 	"process",
 	"sccs",
 	"screen",
+	"sh",
 	"sys",
 	"text",
 	"tree",

sh/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "posixutils-sh"
+version = "0.1.7"
+edition = "2021"
+
+[dependencies]
+plib = { path = "../plib" }
+gettext-rs.workspace = true
+nix = { version = "0.29", features = ["process", "fs", "resource", "signal", "user", "term"] }
+atty = "0.2"
+
+[[bin]]
+name = "sh"
+path = "src/main.rs"

sh/src/builtin/alias.rs

@@ -0,0 +1,45 @@
+//
+// Copyright (c) 2024 Hemi Labs, Inc.
+//
+// This file is part of the posixutils-rs project covered under
+// the MIT License.  For the full license text, please see the LICENSE
+// file in the root directory of this project.
+// SPDX-License-Identifier: MIT
+//
+
+use crate::builtin::{BuiltinResult, BuiltinUtility};
+use crate::shell::opened_files::OpenedFiles;
+use crate::shell::Shell;
+
+pub struct AliasBuiltin;
+
+impl BuiltinUtility for AliasBuiltin {
+    fn exec(
+        &self,
+        args: &[String],
+        shell: &mut Shell,
+        opened_files: &mut OpenedFiles,
+    ) -> BuiltinResult {
+        if args.is_empty() {
+            for (alias, command) in &shell.alias_table {
+                opened_files.write_out(format!("alias {}='{}'", alias, command));
+            }
+            return Ok(0);
+        }
+
+        for arg in args {
+            if let Some(eq_pos) = arg.find('=') {
+                let (alias, command) = arg.split_at(eq_pos);
+                let command = &command[1..];
+                shell
+                    .alias_table
+                    .insert(alias.to_string(), command.to_string());
+            } else if let Some(command) = shell.alias_table.get(arg) {
+                opened_files.write_out(format!("alias {}='{}'", arg, command));
+            } else {
+                return Err(format!("alias: {}: not found", arg).into());
+            }
+        }
+        Ok(0)
+    }
+}

sh/src/builtin/bg.rs

@@ -0,0 +1,87 @@
+//
+// Copyright (c) 2024 Hemi Labs, Inc.
+//
+// This file is part of the posixutils-rs project covered under
+// the MIT License.  For the full license text, please see the LICENSE
+// file in the root directory of this project.
+// SPDX-License-Identifier: MIT
+//
+
+use crate::builtin::{skip_option_terminator, BuiltinResult, BuiltinUtility};
+use crate::jobs::{parse_job_id, Job, JobState};
+use crate::shell::opened_files::OpenedFiles;
+use crate::shell::Shell;
+use nix::sys::signal::kill;
+
+fn run_background_job(
+    arg: &str,
+    job: &mut Job,
+    opened_files: &mut OpenedFiles,
+) -> Result<(), String> {
+    if job.state != JobState::Stopped {
+        return Err(format!(
+            "bg: job {arg} is already running in the background"
+        ));
+    }
+    kill(job.pid, nix::sys::signal::SIGCONT)
+        .map_err(|err| format!("bg: failed to resume job {arg} ({err})"))?;
+    opened_files.write_out(format!("[{}] {}\n", job.number, job.command));
+    job.state = JobState::Running;
+    Ok(())
+}
+pub struct Bg;
+
+impl BuiltinUtility for Bg {
+    fn exec(
+        &self,
+        args: &[String],
+        shell: &mut Shell,
+        opened_files: &mut OpenedFiles,
+    ) -> BuiltinResult {
+        if !shell.set_options.monitor {
+            return Err("bg: cannot use bg when job control is disabled".into());
+        }
+        if !shell.is_interactive {
+            return Err("bg: cannot use bg in a non-interactive shell".into());
+        }
+        if shell.is_subshell {
+            return Err("bg: cannot use bg in a subshell environment".into());
+        }
+
+        let mut status = 0;
+        let args = skip_option_terminator(args);
+        if args.is_empty() {
+            if let Some(job) = shell.background_jobs.current_mut() {
+                if let Err(err) = run_background_job("current", job, opened_files) {
+                    opened_files.write_err(err);
+                    status = 1;
+                }
+            } else {
+                opened_files.write_err("bg: no background jobs");
+                status = 1;
+            }
+        } else {
+            for arg in args {
+                match parse_job_id(arg) {
+                    Ok(job_id) => {
+                        if let Some(job) = shell.background_jobs.get_job_mut(job_id) {
+                            if let Err(err) = run_background_job(arg, job, opened_files) {
+                                opened_files.write_err(err);
+                                status = 1;
+                            }
+                        } else {
+                            opened_files.write_err(format!("bg: '{arg}' no such job"));
+                            status = 1;
+                        }
+                    }
+                    Err(_) => {
+                        opened_files.write_err(format!("bg: '{arg}' no such job"));
+                        status = 1
+                    }
+                }
+            }
+        }
+
+        Ok(status)
+    }
+}