Add option to run command on bell

Fixes #1528.

1 files changed, 76 insertions, 0 deletions

diff --git a/alacritty/src/daemon.rs b/alacritty/src/daemon.rs
new file mode 100644
index 00000000..4a6b6f83
--- /dev/null
+++ b/alacritty/src/daemon.rs
@@ -0,0 +1,76 @@
+use std::ffi::OsStr;
+use std::fmt::Debug;
+use std::io;
+#[cfg(not(windows))]
+use std::os::unix::process::CommandExt;
+#[cfg(windows)]
+use std::os::windows::process::CommandExt;
+use std::process::{Command, Stdio};
+
+use log::{debug, warn};
+
+#[cfg(windows)]
+use winapi::um::winbase::{CREATE_NEW_PROCESS_GROUP, CREATE_NO_WINDOW};
+
+/// Start the daemon and log error on failure.
+pub fn start_daemon<I, S>(program: &str, args: I)
+where
+    I: IntoIterator<Item = S> + Debug + Copy,
+    S: AsRef<OsStr>,
+{
+    match spawn_daemon(program, args) {
+        Ok(_) => debug!("Launched {} with args {:?}", program, args),
+        Err(_) => warn!("Unable to launch {} with args {:?}", program, args),
+    }
+}
+
+#[cfg(windows)]
+fn spawn_daemon<I, S>(program: &str, args: I) -> io::Result<()>
+where
+    I: IntoIterator<Item = S> + Copy,
+    S: AsRef<OsStr>,
+{
+    // Setting all the I/O handles to null and setting the
+    // CREATE_NEW_PROCESS_GROUP and CREATE_NO_WINDOW has the effect
+    // that console applications will run without opening a new
+    // console window.
+    Command::new(program)
+        .args(args)
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .creation_flags(CREATE_NEW_PROCESS_GROUP | CREATE_NO_WINDOW)
+        .spawn()
+        .map(|_| ())
+}
+
+#[cfg(not(windows))]
+fn spawn_daemon<I, S>(program: &str, args: I) -> io::Result<()>
+where
+    I: IntoIterator<Item = S> + Copy,
+    S: AsRef<OsStr>,
+{
+    unsafe {
+        Command::new(program)
+            .args(args)
+            .stdin(Stdio::null())
+            .stdout(Stdio::null())
+            .stderr(Stdio::null())
+            .pre_exec(|| {
+                match libc::fork() {
+                    -1 => return Err(io::Error::last_os_error()),
+                    0 => (),
+                    _ => libc::_exit(0),
+                }
+
+                if libc::setsid() == -1 {
+                    return Err(io::Error::last_os_error());
+                }
+
+                Ok(())
+            })
+            .spawn()?
+            .wait()
+            .map(|_| ())
+    }
+}