fifo_stropen
if ((error = fifo_stropen(&vp1, FREAD|FWRITE, filep->f_cred, 0, 0)) !=
(error = fifo_stropen(&vp2, flag, filep->f_cred, 0, 0)) != 0) {
error = fifo_stropen(vpp, flag, crp, 1, 1);
extern int fifo_stropen(vnode_t **, int, cred_t *, int, int);
if (error = fifo_stropen(&vp1, FWRITE|FREAD, fp1->f_cred, 0, 0))
if (error = fifo_stropen(&vp2, FWRITE|FREAD, fp2->f_cred, 0, 0)) {