1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) International Business Machines Corp., 2001
4 * Ported to LTP: Wayne Boyer
5 * Copyright (c) 2016 Cyril Hrubis <[email protected]>
6 * Copyright (c) Linux Test Project, 2003-2022
7 */
8
9 /*\
10 * [Description]
11 *
12 * Verify that root can provide a negative value to nice() system call and hence
13 * root can decrease the nice value of the process using nice().
14 */
15
16 #include <unistd.h>
17 #include <errno.h>
18 #include <sys/resource.h>
19 #include "tst_test.h"
20
21 #define MIN_PRIO -20
22
23 static int nice_inc[] = {-1, -12, -50};
24
verify_nice(unsigned int i)25 static void verify_nice(unsigned int i)
26 {
27 int new_nice;
28 int orig_nice;
29 int exp_nice;
30 int inc = nice_inc[i];
31 int delta;
32
33 orig_nice = SAFE_GETPRIORITY(PRIO_PROCESS, 0);
34
35 TEST(nice(inc));
36
37 exp_nice = MAX(MIN_PRIO, (orig_nice + inc));
38
39 if (TST_RET != exp_nice) {
40 tst_res(TFAIL | TTERRNO, "nice(%d) returned %li, expected %i",
41 inc, TST_RET, exp_nice);
42 return;
43 }
44
45 if (TST_ERR) {
46 tst_res(TFAIL | TTERRNO, "nice(%d) failed", inc);
47 return;
48 }
49
50 new_nice = SAFE_GETPRIORITY(PRIO_PROCESS, 0);
51
52 if (new_nice != exp_nice) {
53 tst_res(TFAIL, "Process priority %i, expected %i",
54 new_nice, exp_nice);
55 return;
56 }
57
58 tst_res(TPASS, "nice(%d) passed", inc);
59
60 delta = orig_nice - exp_nice;
61 TEST(nice(delta));
62 if (TST_ERR)
63 tst_brk(TBROK | TTERRNO, "nice(%d) failed", delta);
64 }
65
66 static struct tst_test test = {
67 .needs_root = 1,
68 .test = verify_nice,
69 .tcnt = ARRAY_SIZE(nice_inc),
70 };
71