fix: Add Ctrl-C handler for spawned children (#193)

This allows spawned children processes to be killed when a user performs
a Ctrl-C operation. Before this change, children processes would end up
continuing in the background with the user unaware.

Cargo.lock

@@ -287,12 +287,14 @@ dependencies = [
  "chrono",
  "clap",
  "colored",
+ "ctrlc",
  "directories",
  "format_serde_error",
  "indicatif",
  "indicatif-log-bridge",
  "log",
  "log4rs",
+ "nix 0.29.0",
  "nu-ansi-term",
  "once_cell",
  "os_pipe",
@@ -329,6 +331,18 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fd16c4719339c4530435d38e511904438d07cce7950afa3718a84ac36c10e89e"
+
+[[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
 [[package]]
 name = "chrono"
 version = "0.4.38"
@@ -553,6 +567,16 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "ctrlc"
+version = "3.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "672465ae37dc1bc6380a6547a8883d5dd397b0f1faaad4f265726cc7042a5345"
+dependencies = [
+ "nix 0.28.0",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "deranged"
 version = "0.3.11"
@@ -1158,6 +1182,30 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ab250442c86f1850815b5d268639dff018c0627022bc1940eb2d642ca1ce12f0"
 
+[[package]]
+name = "nix"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab2156c4fce2f8df6c499cc1c763e4394b7482525bf2a9701c9d79d215f519e4"
+dependencies = [
+ "bitflags 2.5.0",
+ "cfg-if",
+ "cfg_aliases 0.1.1",
+ "libc",
+]
+
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags 2.5.0",
+ "cfg-if",
+ "cfg_aliases 0.2.1",
+ "libc",
+]
+
 [[package]]
 name = "nom"
 version = "7.1.3"

src/bin/bluebuild.rs

@@ -1,5 +1,5 @@
 use blue_build::commands::{BlueBuildArgs, BlueBuildCommand, CommandArgs};
-use blue_build_utils::logging::Logger;
+use blue_build_utils::{ctrlc_handler, logging::Logger};
 use clap::Parser;
 use log::LevelFilter;
 
@@ -12,6 +12,8 @@ fn main() {
         .log_out_dir(args.log_out.clone())
         .init();
 
+    ctrlc_handler::init();
+
     log::trace!("Parsed arguments: {args:#?}");
 
     match args.command {

src/commands/generate.rs

@@ -119,13 +119,16 @@ impl GenerateCommand {
             .recipe(&recipe_de)
             .recipe_path(recipe_path.as_path())
             .registry(self.get_registry())
-            .exports_tag(if shadow::COMMIT_HASH.is_empty() {
-                // This is done for users who install via
-                // cargo. Cargo installs do not carry git
-                // information via shadow
-                format!("v{}", crate_version!())
-            } else {
-                shadow::COMMIT_HASH.to_string()
+            .exports_tag({
+                #[allow(clippy::const_is_empty)]
+                if shadow::COMMIT_HASH.is_empty() {
+                    // This is done for users who install via
+                    // cargo. Cargo installs do not carry git
+                    // information via shadow
+                    format!("v{}", crate_version!())
+                } else {
+                    shadow::COMMIT_HASH.to_string()
+                }
             })
             .build();
 

utils/Cargo.toml

@@ -12,9 +12,11 @@ license.workspace = true
 atty = "0.2"
 base64 = "0.22.1"
 blake2 = "0.10.6"
+ctrlc = { version = "3.4.4", features = ["termination"] }
 directories = "5"
 rand = "0.8.5"
 log4rs = { version = "1.3.0", features = ["background_rotation"] }
+nix = { version = "0.29.0", features = ["signal"] }
 nu-ansi-term = { version = "0.50.0", features = ["gnu_legacy"] }
 os_pipe = { version = "1", features = ["io_safety"] }
 process_control = { version = "4", features = ["crossbeam-channel"] }

utils/src/ctrlc_handler.rs

@@ -0,0 +1,68 @@
+use std::{
+    process,
+    sync::{Arc, Mutex},
+};
+
+use log::error;
+use nix::{
+    sys::signal::{kill, Signal::SIGTERM},
+    unistd::Pid,
+};
+use once_cell::sync::Lazy;
+
+static PID_LIST: Lazy<Arc<Mutex<Vec<i32>>>> = Lazy::new(|| Arc::new(Mutex::new(vec![])));
+
+/// Initialize Ctrl-C handler. This should be done at the start
+/// of a binary.
+///
+/// # Panics
+/// Will panic if initialized more than once.
+pub fn init() {
+    let pid_list = PID_LIST.clone();
+    ctrlc::set_handler(move || {
+        let pid_list = pid_list.lock().expect("Should lock mutex");
+        pid_list.iter().for_each(|pid| {
+            if let Err(e) = kill(Pid::from_raw(*pid), SIGTERM) {
+                error!("Failed to kill process {pid}: Error {e}");
+            }
+        });
+        drop(pid_list);
+        process::exit(1);
+    })
+    .expect("Should create ctrlc handler");
+}
+
+/// Add a pid to the list to kill when the program
+/// recieves a kill signal.
+///
+/// # Panics
+/// Will panic if the mutex cannot be locked.
+pub fn add_pid<T>(pid: T)
+where
+    T: TryInto<i32>,
+{
+    if let Ok(pid) = pid.try_into() {
+        let mut pid_list = PID_LIST.lock().expect("Should lock pid_list");
+
+        if !pid_list.contains(&pid) {
+            pid_list.push(pid);
+        }
+    }
+}
+
+/// Remove a pid from the list of pids to kill.
+///
+/// # Panics
+/// Will panic if the mutex cannot be locked.
+pub fn remove_pid<T>(pid: T)
+where
+    T: TryInto<i32>,
+{
+    if let Ok(pid) = pid.try_into() {
+        let mut pid_list = PID_LIST.lock().expect("Should lock pid_list");
+
+        if let Some(index) = pid_list.iter().position(|val| *val == pid) {
+            pid_list.swap_remove(index);
+        }
+    }
+}

utils/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod command_output;
 pub mod constants;
+pub mod ctrlc_handler;
 pub mod logging;
 pub mod syntax_highlighting;
 

utils/src/logging.rs

@@ -33,6 +33,8 @@ use once_cell::sync::Lazy;
 use rand::Rng;
 use typed_builder::TypedBuilder;
 
+use crate::ctrlc_handler::{add_pid, remove_pid};
+
 static MULTI_PROGRESS: Lazy<MultiProgress> = Lazy::new(MultiProgress::new);
 static LOG_DIR: Lazy<Mutex<PathBuf>> = Lazy::new(|| Mutex::new(PathBuf::new()));
 
@@ -205,6 +207,9 @@ impl CommandLogging for Command {
 
         let mut child = self.spawn()?;
 
+        let child_pid = child.id();
+        add_pid(child_pid);
+
         // We drop the `Command` to prevent blocking on writer
         // https://docs.rs/os_pipe/latest/os_pipe/#examples
         drop(self);
@@ -243,6 +248,7 @@ impl CommandLogging for Command {
         });
 
         let status = child.wait()?;
+        remove_pid(child_pid);
 
         progress.finish();
         Logger::multi_progress().remove(&progress);