safe_device_open
extern int safe_device_open(const char *file, int mode, int perms);
extern int safe_device_open();
safe_device_open(tape, O_RDONLY, 0600) :
safe_device_open(tape, O_RDONLY|m, 0600))
safe_device_open(tape, O_RDONLY, 0600)) < 0) {
safe_device_open(tape, O_WRONLY, 0600)) < 0)
safe_device_open(tape, O_WRONLY|m, 0600))
safe_device_open(tape, O_RDONLY|m, 0600)) < 0) {