from /etc/environment that are processed by pam_env (8) for all users at login time ... prctl (2) PR_SET_MM_ENV_START and PR_SET_MM_ENV_END operationsthese contexts, which makes the former safe. env Functions marked with env ... environment are all marked with const:env and regarded as unsafe. Being unsafe, the latterdevpath udev (7) $driver udev (7) $env{ key } udev (7) $id udev (7) $kernel udev ... DRIVER udev (7) DRIVERS udev (7) ENV{ key } udev (7) GOTO udev (7) GROUP udevcurrent ->mm->arg_start and current ->mm->env_start : using this helper and the return