5 * # chown root a.out; chmod u+s a.out
21 uid_t real_uid, effective_uid;
25 effective_uid = geteuid();
26 CHECK(setreuid(effective_uid, real_uid));
28 CHECK(setreuid(real_uid, effective_uid));
29 fd = open("/etc/hosts", O_RDONLY);
30 CHECK(setreuid(effective_uid, real_uid));
31 close(fd), fd = -1; /* move this above the previous line */
33 CHECK(setreuid(real_uid, effective_uid));
34 printf("uid %d, euid %d\n", getuid(), geteuid());
35 CHECK(setreuid(effective_uid, real_uid));