pr_open
tmpfd = pr_open(g_proc, file, oflags, 0);
tmpfd = pr_open(g_proc, "/dev/tty", O_RDWR, 0);
(fd = pr_open(P, "/dev/dtrace/helper", O_RDWR, 0)) < 0) {
extern int pr_open(struct ps_prochandle *, const char *, int, mode_t);
fd = pr_open(P, "/dev/zero", PRT_ZERO_OFLAG, 0);