#!/bin/bash
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if [[ ${BASH_SOURCE[0]} == "${0}" ]]; then
    echo "Error: This script must be sourced, not executed directly." >&2
    exit 1
fi

if [[ -n ${OT_ISOLATED_REEXEC:-} ]]; then
    ip link set lo up

    if [[ -d /run ]]; then
        mount -t tmpfs tmpfs /run
    fi

    if [[ -d /var/run && ! -L /var/run ]]; then
        mount -t tmpfs tmpfs /var/run
    fi

    sudo()
    {
        while [[ $# -gt 0 ]]; do
            case "$1" in
                -E)
                    shift
                    ;;
                --)
                    shift
                    break
                    ;;
                -*)
                    echo "Error: unsupported mock sudo option: $1" >&2
                    return 1
                    ;;
                *)
                    break
                    ;;
            esac
        done

        "$@"
    }

    export -f sudo
    return 0
elif [[ $EUID -eq 0 ]]; then
    # Isolation is not necessary
    return 0
elif ! unshare -nmr --kill-child true >/dev/null 2>&1; then
    # Isolation is not supported or restricted (e.g., non-Linux or unprivileged userns disabled)
    return 0
fi

# Unprivileged Linux: Re-exec inside unshare
export OT_ISOLATED_REEXEC=1

CALLER_SCRIPT="${BASH_SOURCE[${#BASH_SOURCE[@]} - 1]:-$0}"
exec unshare -nmr --kill-child bash "$CALLER_SCRIPT" "$@"