feat: update process_exec_tool_call() to take a cancellation token (#6972)

This updates `ExecParams` so that instead of taking `timeout_ms:
Option<u64>`, it now takes a more general cancellation mechanism,
`ExecExpiration`, which is an enum that includes a
`Cancellation(tokio_util::sync::CancellationToken)` variant.

If the cancellation token is fired, then `process_exec_tool_call()`
returns in the same way as if a timeout was exceeded.

This is necessary so that in #6973, we can manage the timeout logic
external to the `process_exec_tool_call()` because we want to "suspend"
the timeout when an elicitation from a human user is pending.








---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/6972).
* #7005
* #6973
* __->__ #6972

codex-rs/core/src/tools/handlers/shell.rs

@@ -37,7 +37,7 @@ impl ShellHandler {
         ExecParams {
             command: params.command,
             cwd: turn_context.resolve_path(params.workdir.clone()),
-            timeout_ms: params.timeout_ms,
+            expiration: params.timeout_ms.into(),
             env: create_env(&turn_context.shell_environment_policy),
             with_escalated_permissions: params.with_escalated_permissions,
             justification: params.justification,
@@ -59,7 +59,7 @@ impl ShellCommandHandler {
         ExecParams {
             command,
             cwd: turn_context.resolve_path(params.workdir.clone()),
-            timeout_ms: params.timeout_ms,
+            expiration: params.timeout_ms.into(),
             env: create_env(&turn_context.shell_environment_policy),
             with_escalated_permissions: params.with_escalated_permissions,
             justification: params.justification,
@@ -243,7 +243,7 @@ impl ShellHandler {
                         let req = ApplyPatchRequest {
                             patch: apply.action.patch.clone(),
                             cwd: apply.action.cwd.clone(),
-                            timeout_ms: exec_params.timeout_ms,
+                            timeout_ms: exec_params.expiration.timeout_ms(),
                             user_explicitly_approved: apply.user_explicitly_approved_this_action,
                             codex_exe: turn.codex_linux_sandbox_exe.clone(),
                         };
@@ -300,7 +300,7 @@ impl ShellHandler {
         let req = ShellRequest {
             command: exec_params.command.clone(),
             cwd: exec_params.cwd.clone(),
-            timeout_ms: exec_params.timeout_ms,
+            timeout_ms: exec_params.expiration.timeout_ms(),
             env: exec_params.env.clone(),
             with_escalated_permissions: exec_params.with_escalated_permissions,
             justification: exec_params.justification.clone(),

codex-rs/core/src/tools/runtimes/apply_patch.rs

@@ -67,7 +67,7 @@ impl ApplyPatchRuntime {
             program,
             args: vec![CODEX_APPLY_PATCH_ARG1.to_string(), req.patch.clone()],
             cwd: req.cwd.clone(),
-            timeout_ms: req.timeout_ms,
+            expiration: req.timeout_ms.into(),
             // Run apply_patch with a minimal environment for determinism and to avoid leaks.
             env: HashMap::new(),
             with_escalated_permissions: None,
@@ -153,9 +153,9 @@ impl ToolRuntime<ApplyPatchRequest, ExecToolCallOutput> for ApplyPatchRuntime {
     ) -> Result<ExecToolCallOutput, ToolError> {
         let spec = Self::build_command_spec(req)?;
         let env = attempt
-            .env_for(&spec)
+            .env_for(spec)
             .map_err(|err| ToolError::Codex(err.into()))?;
-        let out = execute_env(&env, attempt.policy, Self::stdout_stream(ctx))
+        let out = execute_env(env, attempt.policy, Self::stdout_stream(ctx))
             .await
             .map_err(ToolError::Codex)?;
         Ok(out)

codex-rs/core/src/tools/runtimes/mod.rs

@@ -4,6 +4,7 @@ Module: runtimes
 Concrete ToolRuntime implementations for specific tools. Each runtime stays
 small and focused and reuses the orchestrator for approvals + sandbox + retry.
 */
+use crate::exec::ExecExpiration;
 use crate::sandboxing::CommandSpec;
 use crate::tools::sandboxing::ToolError;
 use std::collections::HashMap;
@@ -19,7 +20,7 @@ pub(crate) fn build_command_spec(
     command: &[String],
     cwd: &Path,
     env: &HashMap<String, String>,
-    timeout_ms: Option<u64>,
+    expiration: ExecExpiration,
     with_escalated_permissions: Option<bool>,
     justification: Option<String>,
 ) -> Result<CommandSpec, ToolError> {
@@ -31,7 +32,7 @@ pub(crate) fn build_command_spec(
         args: args.to_vec(),
         cwd: cwd.to_path_buf(),
         env: env.clone(),
-        timeout_ms,
+        expiration,
         with_escalated_permissions,
         justification,
     })

codex-rs/core/src/tools/runtimes/shell.rs

@@ -133,14 +133,14 @@ impl ToolRuntime<ShellRequest, ExecToolCallOutput> for ShellRuntime {
             &req.command,
             &req.cwd,
             &req.env,
-            req.timeout_ms,
+            req.timeout_ms.into(),
             req.with_escalated_permissions,
             req.justification.clone(),
         )?;
         let env = attempt
-            .env_for(&spec)
+            .env_for(spec)
             .map_err(|err| ToolError::Codex(err.into()))?;
-        let out = execute_env(&env, attempt.policy, Self::stdout_stream(ctx))
+        let out = execute_env(env, attempt.policy, Self::stdout_stream(ctx))
             .await
             .map_err(ToolError::Codex)?;
         Ok(out)

codex-rs/core/src/tools/runtimes/unified_exec.rs

@@ -6,6 +6,7 @@ the session manager to spawn PTYs once an ExecEnv is prepared.
 */
 use crate::error::CodexErr;
 use crate::error::SandboxErr;
+use crate::exec::ExecExpiration;
 use crate::tools::runtimes::build_command_spec;
 use crate::tools::sandboxing::Approvable;
 use crate::tools::sandboxing::ApprovalCtx;
@@ -150,13 +151,13 @@ impl<'a> ToolRuntime<UnifiedExecRequest, UnifiedExecSession> for UnifiedExecRunt
             &req.command,
             &req.cwd,
             &req.env,
-            None,
+            ExecExpiration::DefaultTimeout,
             req.with_escalated_permissions,
             req.justification.clone(),
         )
         .map_err(|_| ToolError::Rejected("missing command line for PTY".to_string()))?;
         let exec_env = attempt
-            .env_for(&spec)
+            .env_for(spec)
             .map_err(|err| ToolError::Codex(err.into()))?;
         self.manager
             .open_session_with_exec_env(&exec_env)

codex-rs/core/src/tools/sandboxing.rs

@@ -216,7 +216,7 @@ pub(crate) struct SandboxAttempt<'a> {
 impl<'a> SandboxAttempt<'a> {
     pub fn env_for(
         &self,
-        spec: &CommandSpec,
+        spec: CommandSpec,
     ) -> Result<crate::sandboxing::ExecEnv, SandboxTransformError> {
         self.manager.transform(
             spec,