SYS_open
sysent[SYS_open].sy_call = (sy_call_t *) filemon_wrapper_open;
sysent[SYS_open].sy_call = (sy_call_t *)sys_open;
ATF_REQUIRE(syscall(SYS_open, path, flag) != -1); \
ATF_REQUIRE_EQ(-1, syscall(SYS_open, errpath, flag)); \
case SYS_open: