codex: avoid arg0 dependency cycle in exec-server

Keep the standalone exec-server binary capable of self-dispatching its Linux sandbox helper by materializing a private codex-linux-sandbox symlink at startup. This gives sandbox launch a real helper-looking executable path without depending on the top-level codex-arg0 dispatcher.

Co-authored-by: Codex <noreply@openai.com>

codex-rs/exec-server/Cargo.toml

@@ -20,7 +20,6 @@ arc-swap = { workspace = true }
 async-trait = { workspace = true }
 base64 = { workspace = true }
 clap = { workspace = true, features = ["derive"] }
-codex-arg0 = { workspace = true }
 codex-sandboxing = { workspace = true }
 codex-app-server-protocol = { workspace = true }
 codex-protocol = { workspace = true }
@@ -29,6 +28,7 @@ codex-utils-pty = { workspace = true }
 futures = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
+tempfile = { workspace = true }
 thiserror = { workspace = true }
 tokio = { workspace = true, features = [
     "fs",

codex-rs/exec-server/src/bin/codex-exec-server.rs

@@ -1,6 +1,10 @@
 use clap::Parser;
-use codex_arg0::Arg0DispatchPaths;
-use codex_arg0::arg0_dispatch_or_else;
+
+#[cfg(target_os = "linux")]
+use std::path::PathBuf;
+
+#[cfg(target_os = "linux")]
+use codex_sandboxing::landlock::CODEX_LINUX_SANDBOX_ARG0;
 
 #[derive(Debug, Parser)]
 struct ExecServerArgs {
@@ -14,13 +18,69 @@ struct ExecServerArgs {
 }
 
 fn main() -> anyhow::Result<()> {
-    arg0_dispatch_or_else(|arg0_paths: Arg0DispatchPaths| async move {
+    dispatch_linux_sandbox_arg0();
+
+    let linux_sandbox_alias = LinuxSandboxAlias::create();
+    let codex_linux_sandbox_exe = linux_sandbox_alias.as_ref().map(|alias| alias.path.clone());
+
+    let runtime = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()?;
+    runtime.block_on(async move {
         let args = ExecServerArgs::parse();
-        let runtime =
-            codex_exec_server::ExecServerRuntimeConfig::new(arg0_paths.codex_linux_sandbox_exe);
+        let runtime = codex_exec_server::ExecServerRuntimeConfig::new(codex_linux_sandbox_exe);
         codex_exec_server::run_main_with_runtime(&args.listen, runtime)
             .await
             .map_err(|err| anyhow::Error::msg(err.to_string()))?;
         Ok(())
     })
 }
+
+#[cfg(target_os = "linux")]
+struct LinuxSandboxAlias {
+    _temp_dir: tempfile::TempDir,
+    path: PathBuf,
+}
+
+#[cfg(not(target_os = "linux"))]
+struct LinuxSandboxAlias;
+
+#[cfg(target_os = "linux")]
+impl LinuxSandboxAlias {
+    fn create() -> Option<Self> {
+        let current_exe = std::env::current_exe().ok()?;
+        let temp_dir = tempfile::Builder::new()
+            .prefix("codex-exec-server-")
+            .tempdir()
+            .ok()?;
+        let path = temp_dir.path().join(CODEX_LINUX_SANDBOX_ARG0);
+        std::os::unix::fs::symlink(current_exe, &path).ok()?;
+        Some(Self {
+            _temp_dir: temp_dir,
+            path,
+        })
+    }
+}
+
+#[cfg(not(target_os = "linux"))]
+impl LinuxSandboxAlias {
+    fn create() -> Option<Self> {
+        None
+    }
+}
+
+#[cfg(target_os = "linux")]
+fn dispatch_linux_sandbox_arg0() {
+    let argv0 = std::env::args_os().next().unwrap_or_default();
+    let exe_name = std::path::Path::new(&argv0)
+        .file_name()
+        .and_then(|s| s.to_str())
+        .unwrap_or("");
+
+    if exe_name == CODEX_LINUX_SANDBOX_ARG0 {
+        codex_linux_sandbox::run_main();
+    }
+}
+
+#[cfg(not(target_os = "linux"))]
+fn dispatch_linux_sandbox_arg0() {}