codex-execve-wrapper receives the arguments to an intercepted execve(2) call and delegates the decision to the shell-escalation protocol over a shared file descriptor (specified by the CODEX_ESCALATE_SOCKET environment variable). The server on the other side replies with one of:

Run: codex-execve-wrapper should invoke execve(2) on itself to run the original command within the sandboxed shell.
Escalate: forward the file descriptors of the current process so the command can be run faithfully outside the sandbox. When the process completes, the server forwards the exit code back to codex-execve-wrapper.
Deny: the server has declared the proposed command to be forbidden, so codex-execve-wrapper prints an error to stderr and exits with 1.

Both patched shells use EXEC_WRAPPER to locate codex-execve-wrapper and preserve CODEX_ESCALATE_SOCKET as the inherited escalation socket file descriptor. This shared environment contract lets intercepted commands pass through trees containing either shell without losing the escalation session.

Patched bash

We carry a small patch to execute_cmd.c (see patches/bash-exec-wrapper.patch) that adds support for EXEC_WRAPPER. The patch applies to a8a1c2fac029404d3f42cd39f5a20f24b6e4fe4b from https://git.savannah.gnu.org/git/bash. To rebuild manually:

git clone https://git.savannah.gnu.org/git/bash
git checkout a8a1c2fac029404d3f42cd39f5a20f24b6e4fe4b
git apply /path/to/patches/bash-exec-wrapper.patch
./configure --without-bash-malloc
make -j"$(nproc)"

Release artifacts are built by .github/workflows/rust-release-bash.yml when a codex-bash-vX.Y.Z tag is pushed. Linux artifacts are statically linked against musl, and macOS artifacts target macOS 12 or newer. When the bash commit or patch changes, publish the next version tag.

Patched zsh

We carry a small patch to Src/exec.c (see patches/zsh-exec-wrapper.patch) that adds support for EXEC_WRAPPER. The patch applies to 77045ef899e53b9598bebc5a41db93a548a40ca6 from https://git.code.sf.net/p/zsh/code. To rebuild manually:

git clone https://git.code.sf.net/p/zsh/code
git checkout 77045ef899e53b9598bebc5a41db93a548a40ca6
git apply /path/to/patches/zsh-exec-wrapper.patch
./Util/preconfig
./configure
make -j"$(nproc)"

Release artifacts are built by .github/workflows/rust-release-zsh.yml when a codex-zsh-vX.Y.Z tag is pushed. When the zsh commit or patch changes, publish the next version tag and update the checked-in DotSlash manifests to use the new release.