refactoring plus one small bugfix replaced deep nested conditionals with early exits fixed a small bug in the same go (Note: it is bad to fix bugs during refactoring): The SMTP_HELO case did not break in case of error. Now it does.

FILE *peopen(const char *command, const char *type, char *const envp[], int *ret_pid);

FILE *peidopen(const char *command, const char *type, char *const envp[], int *ret_pid, uid_t uid, gid_t gid);