checksig
fail += checksig("mprotect read", SIGSEGV, SEGV_ACCERR, p);
fail += checksig("mprotect none", SIGSEGV, SEGV_ACCERR, p + 1);
fail += checksig("munmap", SIGSEGV, SEGV_MAPERR, p + 2);
fail += checksig("mmap file", SIGBUS, BUS_OBJERR, p + 3);