fix: separate daemon binary path from CLI to prevent launchd SIGKILL

src/commands/init.rs

@@ -45,7 +45,7 @@ pub fn is_devproxy_process(pid: i32) -> bool {
                 comm.trim()
                     .rsplit('/')
                     .next()
-                    .map(|name| name == "devproxy")
+                    .map(|name| name == "devproxy" || name == "devproxy-daemon")
                     .unwrap_or(false)
             }
             _ => false,
@@ -56,7 +56,7 @@ pub fn is_devproxy_process(pid: i32) -> bool {
         // On Linux, read /proc/<pid>/exe symlink.
         let exe = std::fs::read_link(format!("/proc/{pid}/exe"));
         match exe {
-            Ok(path) => path.file_name().map(|n| n == "devproxy").unwrap_or(false),
+            Ok(path) => path.file_name().map(|n| n == "devproxy" || n == "devproxy-daemon").unwrap_or(false),
             Err(_) => false,
         }
     }
@@ -315,6 +315,23 @@ fn spawn_daemon_directly(exe: &std::path::Path, port: u16, domain: &str) -> Resu
     Ok(())
 }
 
+/// Copy the current binary to the dedicated daemon binary path.
+/// Creates the parent directory if needed, then delegates to
+/// `update::prepare_binary` for permissions and codesigning.
+pub fn install_daemon_binary(src: &std::path::Path, dest: &std::path::Path) -> Result<()> {
+    if let Some(parent) = dest.parent() {
+        std::fs::create_dir_all(parent)
+            .with_context(|| format!("could not create {}", parent.display()))?;
+    }
+    std::fs::copy(src, dest)
+        .with_context(|| format!("could not copy binary to {}", dest.display()))?;
+
+    super::update::prepare_binary(dest)?;
+
+    eprintln!("{} daemon binary installed at {}", "ok:".green(), dest.display());
+    Ok(())
+}
+
 pub fn run(domain: &str, port: u16, no_daemon: bool) -> Result<()> {
     validate_domain(domain)?;
     let config = Config {
@@ -410,6 +427,12 @@ pub fn run(domain: &str, port: u16, no_daemon: bool) -> Result<()> {
         eprintln!("starting daemon on port {port}...");
         let exe = std::env::current_exe().context("could not determine binary path")?;
 
+        // Copy the current binary to a dedicated daemon path so that
+        // launchd's KeepAlive monitoring of the daemon binary does not
+        // SIGKILL normal CLI invocations at the main binary path.
+        let daemon_bin = Config::daemon_binary_path()?;
+        install_daemon_binary(&exe, &daemon_bin)?;
+
         // Try platform-specific socket activation (launchd on macOS,
         // systemd on Linux). The daemon receives pre-bound sockets from
         // the OS, so it runs as the current user — no sudo needed for
@@ -421,7 +444,7 @@ pub fn run(domain: &str, port: u16, no_daemon: bool) -> Result<()> {
         // Pass DEVPROXY_CONFIG_DIR if set — the plist/unit file must
         // embed it so the daemon uses the correct config directory.
         let config_dir_override = std::env::var("DEVPROXY_CONFIG_DIR").ok();
-        match crate::platform::install_daemon(&exe, port, config_dir_override.as_deref()) {
+        match crate::platform::install_daemon(&daemon_bin, port, config_dir_override.as_deref()) {
             Ok(()) => {
                 // Wait for daemon to become responsive (socket activation
                 // startup may be slower than direct spawn)
@@ -468,7 +491,7 @@ pub fn run(domain: &str, port: u16, no_daemon: bool) -> Result<()> {
         }
 
         if !activated {
-            spawn_daemon_directly(&exe, port, domain)?;
+            spawn_daemon_directly(&daemon_bin, port, domain)?;
         }
     }
 

src/commands/update.rs

@@ -136,12 +136,13 @@ fn download_file(url: &str, dest: &Path) -> Result<()> {
 }
 
 /// Set permissions and codesign the binary at `path`.
-fn prepare_binary(path: &Path) -> Result<()> {
+/// Used by both update (for downloaded binaries) and init (for the daemon binary copy).
+pub(crate) fn prepare_binary(path: &Path) -> Result<()> {
     #[cfg(unix)]
     {
         use std::os::unix::fs::PermissionsExt;
         std::fs::set_permissions(path, std::fs::Permissions::from_mode(0o755))
-            .context("failed to set permissions on downloaded binary")?;
+            .context("failed to set binary permissions")?;
     }
 
     #[cfg(target_os = "macos")]
@@ -320,6 +321,13 @@ fn do_update(download_url: &str, exe_path: &Path, tmpfile: &Path) -> Result<()>
 
     replace_binary(tmpfile, exe_path)?;
 
+    // Also update the dedicated daemon binary so that the launchd/systemd
+    // managed daemon picks up the new version on restart.
+    let daemon_bin = crate::config::Config::daemon_binary_path()?;
+    if daemon_bin.exists() {
+        super::init::install_daemon_binary(exe_path, &daemon_bin)?;
+    }
+
     Ok(())
 }
 

src/config.rs

@@ -57,6 +57,32 @@ impl Config {
         Ok(Self::config_dir()?.join("daemon.log"))
     }
 
+    /// Returns the path to the dedicated daemon binary.
+    ///
+    /// The daemon binary is stored separately from the CLI binary so that
+    /// launchd's KeepAlive monitoring of the daemon path does not interfere
+    /// with normal CLI invocations (e.g., `devproxy --version`).
+    ///
+    /// Default path (via `dirs::data_dir()`):
+    /// - macOS: `~/Library/Application Support/devproxy/devproxy-daemon`
+    /// - Linux: `~/.local/share/devproxy/devproxy-daemon`
+    ///
+    /// Respects `DEVPROXY_DATA_DIR` env var for test isolation.
+    ///
+    /// Note: this path is only resolved by CLI commands (`init`, `update`)
+    /// to install/update the daemon binary. The daemon process itself never
+    /// calls this function, so `DEVPROXY_DATA_DIR` does not need to be
+    /// propagated into plist/unit environment variables.
+    pub fn daemon_binary_path() -> Result<PathBuf> {
+        if let Ok(dir) = std::env::var("DEVPROXY_DATA_DIR") {
+            return Ok(PathBuf::from(dir).join("devproxy-daemon"));
+        }
+        let dir = dirs::data_dir()
+            .context("could not determine data directory")?
+            .join("devproxy");
+        Ok(dir.join("devproxy-daemon"))
+    }
+
     pub fn save(&self) -> Result<()> {
         let dir = Self::config_dir()?;
         std::fs::create_dir_all(&dir)?;

tests/e2e.rs

@@ -1201,6 +1201,14 @@ fn test_launchd_socket_activation() {
             plist_content.contains(&daemon_port.to_string()),
             "plist should contain port {daemon_port}"
         );
+
+        // Verify the plist references the daemon binary path (not the CLI binary)
+        assert!(
+            plist_content.contains("devproxy-daemon"),
+            "plist should reference the dedicated daemon binary (devproxy-daemon), \
+             not the CLI binary. This prevents launchd KeepAlive from SIGKILL'ing \
+             normal CLI invocations."
+        );
     }
 
     // Cleanup: bootout the agent and remove plist
@@ -1235,3 +1243,192 @@ fn test_launchd_socket_activation() {
 
     let _ = std::fs::remove_dir_all(&config_dir);
 }
+
+/// Verify that `devproxy --version` works even when a daemon is running.
+///
+/// This is the core regression test for the launchd SIGKILL bug: launchd's
+/// KeepAlive=true causes it to SIGKILL any non-managed process at the
+/// managed binary path. By using a separate daemon binary path, the CLI
+/// binary is free from launchd interference.
+///
+/// This test verifies the structural fix: init installs a daemon binary at
+/// a separate path, and --version runs cleanly from the CLI binary.
+#[test]
+#[ignore] // Run with: cargo test --test e2e -- --ignored test_version_works_with_daemon_running
+fn test_version_works_with_daemon_running() {
+    let config_dir = create_test_config_dir("ver-daemon");
+    let port = find_free_port();
+
+    // Start a daemon in the background. The daemon needs TLS certs which
+    // create_test_config_dir already generates via `init --no-daemon`.
+    let _guard = start_test_daemon(&config_dir, port);
+
+    // Run --version — this must succeed even while a daemon is running.
+    // In the launchd SIGKILL bug, running the binary at the launchd-managed
+    // path would get killed. With the daemon binary path separation fix,
+    // the CLI binary path is not managed by launchd.
+    let output = Command::new(devproxy_bin())
+        .args(["--version"])
+        .env("DEVPROXY_CONFIG_DIR", &config_dir)
+        .env("DEVPROXY_NO_SOCKET_ACTIVATION", "1")
+        .output()
+        .expect("failed to run devproxy --version");
+
+    assert!(
+        output.status.success(),
+        "devproxy --version should succeed (exit {}): stderr={}",
+        output.status.code().unwrap_or(-1),
+        String::from_utf8_lossy(&output.stderr)
+    );
+
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    assert!(
+        stdout.contains("devproxy"),
+        "--version should print version info: {stdout}"
+    );
+}
+
+/// Verify that init with daemon installs the daemon binary at the
+/// DEVPROXY_DATA_DIR path and that the daemon binary path differs
+/// from the CLI binary path.
+#[test]
+fn test_init_daemon_binary_path_separation() {
+    let config_dir = std::env::temp_dir().join(format!(
+        "devproxy-config-path-sep-{}",
+        std::process::id()
+    ));
+    let data_dir = std::env::temp_dir().join(format!(
+        "devproxy-data-path-sep-{}",
+        std::process::id()
+    ));
+    if config_dir.exists() {
+        std::fs::remove_dir_all(&config_dir).unwrap();
+    }
+    if data_dir.exists() {
+        std::fs::remove_dir_all(&data_dir).unwrap();
+    }
+    std::fs::create_dir_all(&config_dir).unwrap();
+    std::fs::create_dir_all(&data_dir).unwrap();
+
+    let port = find_free_port();
+
+    // Run init with daemon (uses fallback spawn since DEVPROXY_NO_SOCKET_ACTIVATION=1)
+    let output = Command::new(devproxy_bin())
+        .args([
+            "init",
+            "--domain",
+            TEST_DOMAIN,
+            "--port",
+            &port.to_string(),
+        ])
+        .env("DEVPROXY_CONFIG_DIR", &config_dir)
+        .env("DEVPROXY_DATA_DIR", &data_dir)
+        .env("DEVPROXY_NO_SOCKET_ACTIVATION", "1")
+        .output()
+        .expect("failed to run devproxy init");
+
+    let stderr = String::from_utf8_lossy(&output.stderr);
+    eprintln!("init stderr: {stderr}");
+
+    assert!(
+        output.status.success(),
+        "init should succeed: {stderr}"
+    );
+
+    // Verify daemon binary was installed at the data dir path
+    let daemon_bin = data_dir.join("devproxy-daemon");
+    assert!(
+        daemon_bin.exists(),
+        "daemon binary should be installed at {}: {stderr}",
+        daemon_bin.display()
+    );
+
+    // Verify daemon binary path is different from CLI binary path
+    let cli_bin = devproxy_bin();
+    assert_ne!(
+        cli_bin, daemon_bin,
+        "daemon binary path should differ from CLI binary path"
+    );
+
+    // Verify --version works from CLI binary while daemon is running
+    let version_output = Command::new(&cli_bin)
+        .args(["--version"])
+        .env("DEVPROXY_CONFIG_DIR", &config_dir)
+        .output()
+        .expect("failed to run --version");
+
+    assert!(
+        version_output.status.success(),
+        "--version should succeed while daemon is running (exit {}): {}",
+        version_output.status.code().unwrap_or(-1),
+        String::from_utf8_lossy(&version_output.stderr)
+    );
+
+    // Clean up daemon
+    let pid_path = config_dir.join("daemon.pid");
+    if pid_path.exists() {
+        if let Ok(pid_str) = std::fs::read_to_string(&pid_path) {
+            if let Ok(pid) = pid_str.trim().parse::<i32>() {
+                unsafe {
+                    libc::kill(pid, libc::SIGTERM);
+                }
+                std::thread::sleep(Duration::from_millis(500));
+                unsafe {
+                    libc::kill(pid, libc::SIGKILL);
+                }
+            }
+        }
+    }
+
+    let _ = std::fs::remove_dir_all(&config_dir);
+    let _ = std::fs::remove_dir_all(&data_dir);
+}
+
+/// Verify that the daemon binary at the data dir path can run --version
+/// and produce the same output as the CLI binary.
+#[test]
+fn test_daemon_binary_matches_cli_binary() {
+    let data_dir = std::env::temp_dir().join(format!(
+        "devproxy-data-match-{}",
+        std::process::id()
+    ));
+    if data_dir.exists() {
+        std::fs::remove_dir_all(&data_dir).unwrap();
+    }
+    std::fs::create_dir_all(&data_dir).unwrap();
+
+    let cli_bin = devproxy_bin();
+    let daemon_bin = data_dir.join("devproxy-daemon");
+
+    // Copy CLI binary to daemon path (simulating what init does)
+    std::fs::copy(&cli_bin, &daemon_bin).unwrap();
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        std::fs::set_permissions(&daemon_bin, std::fs::Permissions::from_mode(0o755)).unwrap();
+    }
+
+    let cli_output = Command::new(&cli_bin)
+        .args(["--version"])
+        .output()
+        .expect("CLI --version failed");
+    let daemon_output = Command::new(&daemon_bin)
+        .args(["--version"])
+        .output()
+        .expect("daemon --version failed");
+
+    assert!(cli_output.status.success(), "CLI --version should succeed");
+    assert!(
+        daemon_output.status.success(),
+        "daemon binary --version should succeed"
+    );
+
+    let cli_version = String::from_utf8_lossy(&cli_output.stdout);
+    let daemon_version = String::from_utf8_lossy(&daemon_output.stdout);
+    assert_eq!(
+        cli_version, daemon_version,
+        "CLI and daemon binaries should report the same version"
+    );
+
+    let _ = std::fs::remove_dir_all(&data_dir);
+}