1 #include <sys/types.h>
2 #include <unistd.h>
3 #include <stdio.h>
4 #include <assert.h>
5
main()6 int main()
7 {
8 printf("Current uid: %d, euid: %d, gid: %d, egid: %d\n\n", getuid(), geteuid(), getgid(), getegid());
9
10 // 测试uid
11 printf("Set uid 1000\n");
12 setuid(1000);
13 int uid = getuid();
14 assert(uid == 1000);
15 printf("Current uid:%d\n\n", uid);
16
17 // 测试gid
18 printf("Set gid 1000\n");
19 setgid(1000);
20 int gid = getgid();
21 assert(gid == 1000);
22 printf("Current gid:%d\n\n", gid);
23
24 // 测试euid
25 printf("Setg euid 1000\n");
26 seteuid(1000);
27 int euid = geteuid();
28 assert(euid == 1000);
29 printf("Current euid:%d\n\n", euid);
30
31 // 测试egid
32 printf("Set egid 1000\n");
33 setegid(1000);
34 int egid = getegid();
35 assert(egid == 1000);
36 printf("Current egid:%d\n\n", egid);
37
38 // 测试uid在非root用户下无法修改
39 printf("Try to setuid for non_root.\n");
40 assert(setuid(0) < 0); // 非root用户无法修改uid
41 printf("Current uid: %d, euid: %d, gid: %d, egid: %d\n", getuid(), geteuid(), getgid(), getegid());
42 }