cam_open_device
struct cam_device * cam_open_device(const char *path, int flags);
ATF_CHECK(cam_open_device(cam_test_device, O_RDONLY) == NULL);
ATF_REQUIRE(cam_open_device("/nonexistent", O_RDWR) == NULL);
ATF_CHECK(cam_open_device(cam_test_device, O_RDONLY) == NULL);
ATF_CHECK(cam_open_device(cam_test_device, O_RDWR) == NULL);
cam_dev = cam_open_device(cam_test_device, O_RDWR);
cam_dev = cam_open_device(cam_test_device, O_RDWR);
dev = cam_open_device(disks[count].devname, O_RDWR);