1 /*
2 * Copyright (c) 2015 Eugene Syromyatnikov <evgsyr@gmail.com>
3 * Copyright (c) 2015-2016 Dmitry V. Levin <ldv@altlinux.org>
4 * Copyright (c) 2015-2017 The strace developers.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /**
31 * @file
32 * This test burns some CPU cycles in user space and kernel space in order to
33 * get some non-zero values returned by times(2).
34 */
35
36 #include "tests.h"
37 #include <sched.h>
38 #include <stdio.h>
39 #include <time.h>
40 #include <unistd.h>
41
42 #include <asm/unistd.h>
43 #include <sys/times.h>
44 #include <sys/wait.h>
45
46 enum {
47 NUM_USER_ITERS = 1000000,
48 PARENT_CPUTIME_LIMIT_NSEC = 200000000,
49 CHILD_CPUTIME_LIMIT_NSEC = 300000000
50 };
51
52 int
main(void)53 main(void)
54 {
55 struct timespec ts;
56 volatile int dummy = 0;
57 int i = 0;
58
59 pid_t pid = fork();
60 if (pid < 0)
61 perror_msg_and_fail("fork");
62
63 const long cputime_limit =
64 pid ? PARENT_CPUTIME_LIMIT_NSEC : CHILD_CPUTIME_LIMIT_NSEC;
65
66 /* Enjoying my user time */
67 while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
68 if (ts.tv_sec || ts.tv_nsec >= cputime_limit)
69 break;
70
71 if (i && !(ts.tv_sec || ts.tv_nsec))
72 error_msg_and_skip("clock_gettime(CLOCK_PROCESS_CPUTIME_ID, {0, 0})");
73
74 for (i = 0; i < NUM_USER_ITERS; ++i)
75 ++dummy;
76 }
77
78 /* Enjoying my system time */
79 while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
80 if (ts.tv_sec || ts.tv_nsec >= cputime_limit * 2)
81 break;
82
83 sched_yield();
84 }
85
86 if (pid == 0) {
87 return 0;
88 } else {
89 wait(NULL);
90 }
91
92 struct tms tbuf;
93 unsigned long long llres;
94
95 /*
96 * On systems where user's and kernel's long types are the same,
97 * prefer direct times syscall over libc's times function because
98 * the latter is more prone to return value truncation.
99 */
100 #undef USE_LIBC_SYSCALL
101 #if defined __NR_times && \
102 !defined(LINUX_MIPSN32) && \
103 !(defined __x86_64__ && defined __ILP32__)
104 # define USE_LIBC_SYSCALL 1
105 #endif
106
107 #if defined USE_LIBC_SYSCALL
108 long res = syscall(__NR_times, &tbuf);
109
110 if (-1L == res)
111 perror_msg_and_skip("times");
112 else
113 llres = (unsigned long) res;
114 #elif defined __NR_times && defined __x86_64__ && defined __ILP32__
115 register long arg asm("rdi") = (long) &tbuf;
116 asm volatile("syscall\n\t"
117 : "=a"(llres)
118 : "0"(__NR_times), "r"(arg)
119 : "memory", "cc", "r11", "cx");
120 if (llres > 0xfffffffffffff000)
121 return 77;
122 #else
123 clock_t res = times(&tbuf);
124
125 if ((clock_t) -1 == res)
126 perror_msg_and_skip("times");
127 if (sizeof(res) < sizeof(unsigned long long))
128 llres = (unsigned long) res;
129 else
130 llres = res;
131 #endif
132
133 printf("times({tms_utime=%llu, tms_stime=%llu, ",
134 (unsigned long long) tbuf.tms_utime,
135 (unsigned long long) tbuf.tms_stime);
136 printf("tms_cutime=%llu, tms_cstime=%llu}) = %llu\n",
137 (unsigned long long) tbuf.tms_cutime,
138 (unsigned long long) tbuf.tms_cstime,
139 llres);
140 puts("+++ exited with 0 +++");
141
142 return 0;
143 }
144