1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2019 FUJITSU LIMITED. All rights reserved.
4 * Author: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
5 *
6 * Test PR_GET_TIMERSLACK and PR_SET_TIMERSLACK of prctl(2).
7 * 1)Each thread has two associated timer slack values: a "default"
8 * value, and a "current" value. PR_SET_TIMERSLACK sets the "current"
9 * timer slack value for the calling thread.
10 * 2)When a new thread is created, the two timer slack values are made
11 * the same as the "current" value of the creating thread.
12 * 3)The maximum timer slack value is ULONG_MAX. On 32bit machines, it
13 * is a valid value(about 4s). On 64bit machines, it is about 500 years
14 * and no person will set this over 4s. prctl return value is int, so
15 * we test themaximum value is INT_MAX.
16 * 4)we also check current value via /proc/self/timerslack_ns if it is
17 * supported.
18 */
19
20 #include <sys/prctl.h>
21 #include <string.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <linux/limits.h>
25 #include "lapi/syscalls.h"
26 #include "lapi/prctl.h"
27 #include "tst_test.h"
28
29 #define PROC_TIMERSLACK_PATH "/proc/self/timerslack_ns"
30
31 static void check_reset_timerslack(char *message);
32 static void check_get_timerslack(char *message, unsigned long value);
33 static void check_inherit_timerslack(char *message, unsigned long value);
34 static unsigned long origin_value;
35
36 static struct tcase {
37 void (*func_check)();
38 unsigned long setvalue;
39 unsigned long expvalue;
40 char message[50];
41 } tcases[] = {
42 {check_reset_timerslack, 0, 50000, "Reset"},
43 {check_get_timerslack, 1, 1, "Min"},
44 {check_get_timerslack, 70000, 70000, "Middle"},
45 {check_get_timerslack, INT_MAX, INT_MAX, "Max"},
46 {check_inherit_timerslack, 70000, 70000, "Child process"},
47 };
48
49 static int proc_flag = 1;
50
check_reset_timerslack(char * message)51 static void check_reset_timerslack(char *message)
52 {
53 check_get_timerslack(message, origin_value);
54 }
55
check_get_timerslack(char * message,unsigned long value)56 static void check_get_timerslack(char *message, unsigned long value)
57 {
58 TEST(prctl(PR_GET_TIMERSLACK));
59 if ((unsigned long)TST_RET == value)
60 tst_res(TPASS, "%s prctl(PR_GET_TIMERSLACK) got %lu expectedly",
61 message, value);
62 else
63 tst_res(TFAIL, "%s prctl(PR_GET_TIMERSLACK) expected %lu got %lu",
64 message, value, TST_RET);
65
66 if (proc_flag)
67 TST_ASSERT_INT(PROC_TIMERSLACK_PATH, value);
68 }
69
check_inherit_timerslack(char * message,unsigned long value)70 static void check_inherit_timerslack(char *message, unsigned long value)
71 {
72 int pid;
73 unsigned long current_value;
74 unsigned long default_value;
75
76 pid = SAFE_FORK();
77 if (pid == 0) {
78 current_value = prctl(PR_GET_TIMERSLACK);
79 prctl(PR_SET_TIMERSLACK, 0);
80 default_value = prctl(PR_GET_TIMERSLACK);
81 if (current_value == value && default_value == value)
82 tst_res(TPASS,
83 "%s two timer slack values are made the same as the current value(%lu) of the creating thread.",
84 message, value);
85 else
86 tst_res(TFAIL,
87 "%s current_value is %lu, default value is %lu, the parent current value is %lu",
88 message, current_value, default_value, value);
89 }
90
91 }
92
verify_prctl(unsigned int n)93 static void verify_prctl(unsigned int n)
94 {
95 struct tcase *tc = &tcases[n];
96
97 TEST(prctl(PR_SET_TIMERSLACK, tc->setvalue));
98 if (TST_RET == -1) {
99 tst_res(TFAIL | TTERRNO, "prctl(PR_SET_TIMERSLACK, %lu) failed",
100 tc->setvalue);
101 return;
102 }
103
104 tst_res(TPASS, "prctl(PR_SET_TIMERSLACK, %lu) succeed", tc->setvalue);
105 tc->func_check(tc->message, tc->expvalue);
106 }
107
setup(void)108 static void setup(void)
109 {
110 if (access(PROC_TIMERSLACK_PATH, F_OK) == -1) {
111 tst_res(TCONF, "proc doesn't support timerslack_ns interface");
112 proc_flag = 0;
113 }
114
115 TEST(prctl(PR_GET_TIMERSLACK));
116 origin_value = TST_RET;
117 tst_res(TINFO, "current timerslack value is %lu", origin_value);
118 }
119
120 static struct tst_test test = {
121 .setup = setup,
122 .test = verify_prctl,
123 .tcnt = ARRAY_SIZE(tcases),
124 .forks_child = 1,
125 };
126