execpolicy2 core integration (#6641)

This PR threads execpolicy2 into codex-core.

activated via feature flag: exec_policy (on by default)

reads and parses all .codexpolicy files in `codex_home/codex`

refactored tool runtime API to integrate execpolicy logic

---------

Co-authored-by: Michael Bolin <mbolin@openai.com>

codex-rs/core/src/codex.rs

@@ -121,6 +121,7 @@ use crate::user_instructions::UserInstructions;
 use crate::user_notification::UserNotification;
 use crate::util::backoff;
 use codex_async_utils::OrCancelExt;
+use codex_execpolicy2::Policy as ExecPolicy;
 use codex_otel::otel_event_manager::OtelEventManager;
 use codex_protocol::config_types::ReasoningEffort as ReasoningEffortConfig;
 use codex_protocol::config_types::ReasoningSummary as ReasoningSummaryConfig;
@@ -167,6 +168,10 @@ impl Codex {
 
         let user_instructions = get_user_instructions(&config).await;
 
+        let exec_policy = crate::exec_policy::exec_policy_for(&config.features, &config.codex_home)
+            .await
+            .map_err(|err| CodexErr::Fatal(format!("failed to load execpolicy: {err}")))?;
+
         let config = Arc::new(config);
 
         let session_configuration = SessionConfiguration {
@@ -183,6 +188,7 @@ impl Codex {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             features: config.features.clone(),
+            exec_policy,
             session_source,
         };
 
@@ -280,6 +286,7 @@ pub(crate) struct TurnContext {
     pub(crate) final_output_json_schema: Option<Value>,
     pub(crate) codex_linux_sandbox_exe: Option<PathBuf>,
     pub(crate) tool_call_gate: Arc<ReadinessFlag>,
+    pub(crate) exec_policy: Arc<ExecPolicy>,
     pub(crate) truncation_policy: TruncationPolicy,
 }
 
@@ -336,6 +343,8 @@ pub(crate) struct SessionConfiguration {
 
     /// Set of feature flags for this session
     features: Features,
+    /// Execpolicy policy, applied only when enabled by feature flag.
+    exec_policy: Arc<ExecPolicy>,
 
     // TODO(pakrym): Remove config from here
     original_config_do_not_use: Arc<Config>,
@@ -436,6 +445,7 @@ impl Session {
             final_output_json_schema: None,
             codex_linux_sandbox_exe: config.codex_linux_sandbox_exe.clone(),
             tool_call_gate: Arc::new(ReadinessFlag::new()),
+            exec_policy: session_configuration.exec_policy.clone(),
             truncation_policy: TruncationPolicy::new(&per_turn_config),
         }
     }
@@ -1789,6 +1799,7 @@ async fn spawn_review_thread(
         final_output_json_schema: None,
         codex_linux_sandbox_exe: parent_turn_context.codex_linux_sandbox_exe.clone(),
         tool_call_gate: Arc::new(ReadinessFlag::new()),
+        exec_policy: parent_turn_context.exec_policy.clone(),
         truncation_policy: TruncationPolicy::new(&per_turn_config),
     };
 
@@ -2608,6 +2619,7 @@ mod tests {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             features: Features::default(),
+            exec_policy: Arc::new(codex_execpolicy2::Policy::empty()),
             session_source: SessionSource::Exec,
         };
 
@@ -2685,6 +2697,7 @@ mod tests {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             features: Features::default(),
+            exec_policy: Arc::new(codex_execpolicy2::Policy::empty()),
             session_source: SessionSource::Exec,
         };