codex/codex-rs/linux-sandbox/src/exec_util.rs

use std::ffi::CString;
use std::fs::File;
use std::os::fd::AsRawFd;

pub(crate) fn argv_to_cstrings(argv: &[String]) -> Vec<CString> {
    let mut cstrings: Vec<CString> = Vec::with_capacity(argv.len());
    for arg in argv {
        match CString::new(arg.as_str()) {
            Ok(value) => cstrings.push(value),
            Err(err) => panic!("failed to convert argv to CString: {err}"),
        }
    }
    cstrings
}

pub(crate) fn make_files_inheritable(files: &[File]) {
    for file in files {
        clear_cloexec(file.as_raw_fd());
    }
}

fn clear_cloexec(fd: libc::c_int) {
    // SAFETY: `fd` is an owned descriptor kept alive by `files`.
    let flags = unsafe { libc::fcntl(fd, libc::F_GETFD) };
    if flags < 0 {
        let err = std::io::Error::last_os_error();
        panic!("failed to read fd flags for preserved bubblewrap file descriptor {fd}: {err}");
    }
    let cleared_flags = flags & !libc::FD_CLOEXEC;
    if cleared_flags == flags {
        return;
    }

    // SAFETY: `fd` is valid and we are only clearing FD_CLOEXEC.
    let result = unsafe { libc::fcntl(fd, libc::F_SETFD, cleared_flags) };
    if result < 0 {
        let err = std::io::Error::last_os_error();
        panic!("failed to clear CLOEXEC for preserved bubblewrap file descriptor {fd}: {err}");
    }
}

#[cfg(test)]
#[path = "exec_util_tests.rs"]
mod tests;