File: tst-cpuclock1.c

package info (click to toggle)
glibc 2.24-11+deb9u4
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 225,852 kB
  • sloc: ansic: 996,505; asm: 261,827; sh: 10,484; makefile: 9,856; cpp: 4,169; python: 3,971; perl: 2,254; awk: 1,753; pascal: 1,521; yacc: 291; sed: 80
file content (321 lines) | stat: -rw-r--r-- 8,265 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
/* Test program for process CPU clocks.
   Copyright (C) 2004-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <sys/wait.h>

/* This function is intended to rack up both user and system time.  */
static void
chew_cpu (void)
{
  while (1)
    {
      static volatile char buf[4096];
      for (int i = 0; i < 100; ++i)
	for (size_t j = 0; j < sizeof buf; ++j)
	  buf[j] = 0xaa;
      int nullfd = open ("/dev/null", O_WRONLY);
      for (int i = 0; i < 100; ++i)
	for (size_t j = 0; j < sizeof buf; ++j)
	  buf[j] = 0xbb;
      write (nullfd, (char *) buf, sizeof buf);
      close (nullfd);
      if (getppid () == 1)
	_exit (2);
    }
}

static int
do_test (void)
{
  int result = 0;
  clockid_t cl;
  int e;
  pid_t dead_child, child;

  /* Fork a child and let it die, to give us a PID known not be valid
     (assuming PIDs don't wrap around during the test).  */
  {
    dead_child = fork ();
    if (dead_child == 0)
      _exit (0);
    if (dead_child < 0)
      {
	perror ("fork");
	return 1;
      }
    int x;
    if (wait (&x) != dead_child)
      {
	perror ("wait");
	return 2;
      }
  }

  /* POSIX says we should get ESRCH for this.  */
  e = clock_getcpuclockid (dead_child, &cl);
  if (e != ENOSYS && e != ESRCH && e != EPERM)
    {
      printf ("clock_getcpuclockid on dead PID %d => %s\n",
	      dead_child, strerror (e));
      result = 1;
    }

  /* Now give us a live child eating up CPU time.  */
  child = fork ();
  if (child == 0)
    {
      chew_cpu ();
      _exit (1);
    }
  if (child < 0)
    {
      perror ("fork");
      return 1;
    }

  e = clock_getcpuclockid (child, &cl);
  if (e == EPERM)
    {
      puts ("clock_getcpuclockid does not support other processes");
      goto done;
    }
  if (e != 0)
    {
      printf ("clock_getcpuclockid on live PID %d => %s\n",
	      child, strerror (e));
      result = 1;
      goto done;
    }

  const clockid_t child_clock = cl;
  struct timespec res;
  if (clock_getres (child_clock, &res) < 0)
    {
      printf ("clock_getres on live PID %d clock %lx => %s\n",
	      child, (unsigned long int) child_clock, strerror (errno));
      result = 1;
      goto done;
    }
  printf ("live PID %d clock %lx resolution %ju.%.9ju\n",
	  child, (unsigned long int) child_clock,
	  (uintmax_t) res.tv_sec, (uintmax_t) res.tv_nsec);

  struct timespec before, after;
  if (clock_gettime (child_clock, &before) < 0)
    {
      printf ("clock_gettime on live PID %d clock %lx => %s\n",
	      child, (unsigned long int) child_clock, strerror (errno));
      result = 1;
      goto done;
    }
  /* Should be close to 0.0.  */
  printf ("live PID %d before sleep => %ju.%.9ju\n",
	  child, (uintmax_t) before.tv_sec, (uintmax_t) before.tv_nsec);

  struct timespec sleeptime = { .tv_nsec = 500000000 };
  if (nanosleep (&sleeptime, NULL) != 0)
    {
      perror ("nanosleep");
      result = 1;
      goto done;
    }

  if (clock_gettime (child_clock, &after) < 0)
    {
      printf ("clock_gettime on live PID %d clock %lx => %s\n",
	      child, (unsigned long int) child_clock, strerror (errno));
      result = 1;
      goto done;
    }
  /* Should be close to 0.5.  */
  printf ("live PID %d after sleep => %ju.%.9ju\n",
	  child, (uintmax_t) after.tv_sec, (uintmax_t) after.tv_nsec);

  struct timespec diff = { .tv_sec = after.tv_sec - before.tv_sec,
			   .tv_nsec = after.tv_nsec - before.tv_nsec };
  if (diff.tv_nsec < 0)
    {
      --diff.tv_sec;
      diff.tv_nsec += 1000000000;
    }
  if (diff.tv_sec != 0
      || diff.tv_nsec > 600000000
      || diff.tv_nsec < 100000000)
    {
      printf ("before - after %ju.%.9ju outside reasonable range\n",
	      (uintmax_t) diff.tv_sec, (uintmax_t) diff.tv_nsec);
      result = 1;
    }

  sleeptime.tv_nsec = 100000000;
  e = clock_nanosleep (child_clock, 0, &sleeptime, NULL);
  if (e == EINVAL || e == ENOTSUP || e == ENOSYS)
    {
      printf ("clock_nanosleep not supported for other process clock: %s\n",
	      strerror (e));
    }
  else if (e != 0)
    {
      printf ("clock_nanosleep on other process clock: %s\n", strerror (e));
      result = 1;
    }
  else
    {
      struct timespec afterns;
      if (clock_gettime (child_clock, &afterns) < 0)
	{
	  printf ("clock_gettime on live PID %d clock %lx => %s\n",
		  child, (unsigned long int) child_clock, strerror (errno));
	  result = 1;
	}
      else
	{
	  struct timespec d = { .tv_sec = afterns.tv_sec - after.tv_sec,
				.tv_nsec = afterns.tv_nsec - after.tv_nsec };
	  if (d.tv_nsec < 0)
	    {
	      --d.tv_sec;
	      d.tv_nsec += 1000000000;
	    }
	  if (d.tv_sec > 0
	      || d.tv_nsec < sleeptime.tv_nsec
	      || d.tv_nsec > sleeptime.tv_nsec * 2)
	    {
	      printf ("nanosleep time %ju.%.9ju outside reasonable range\n",
		      (uintmax_t) d.tv_sec, (uintmax_t) d.tv_nsec);
	      result = 1;
	    }
	}
    }

  if (kill (child, SIGKILL) != 0)
    {
      perror ("kill");
      result = 2;
      goto done;
    }

  /* Wait long enough to let the child finish dying.  */

  sleeptime.tv_nsec = 200000000;
  if (nanosleep (&sleeptime, NULL) != 0)
    {
      perror ("nanosleep");
      result = 1;
      goto done;
    }

  struct timespec dead;
  if (clock_gettime (child_clock, &dead) < 0)
    {
      printf ("clock_gettime on dead PID %d clock %lx => %s\n",
	      child, (unsigned long int) child_clock, strerror (errno));
      result = 1;
      goto done;
    }
  /* Should be close to 0.6.  */
  printf ("dead PID %d => %ju.%.9ju\n",
	  child, (uintmax_t) dead.tv_sec, (uintmax_t) dead.tv_nsec);

  diff.tv_sec = dead.tv_sec - after.tv_sec;
  diff.tv_nsec = dead.tv_nsec - after.tv_nsec;
  if (diff.tv_nsec < 0)
    {
      --diff.tv_sec;
      diff.tv_nsec += 1000000000;
    }
  if (diff.tv_sec != 0 || diff.tv_nsec > 200000000)
    {
      printf ("dead - after %ju.%.9ju outside reasonable range\n",
	      (uintmax_t) diff.tv_sec, (uintmax_t) diff.tv_nsec);
      result = 1;
    }

  /* Now reap the child and verify that its clock is no longer valid.  */
  {
    int x;
    if (waitpid (child, &x, 0) != child)
      {
	perror ("waitpid");
	result = 1;
      }
  }

  if (clock_gettime (child_clock, &dead) == 0)
    {
      printf ("clock_gettime on reaped PID %d clock %lx => %ju%.9ju\n",
	      child, (unsigned long int) child_clock,
	      (uintmax_t) dead.tv_sec, (uintmax_t) dead.tv_nsec);
      result = 1;
    }
  else
    {
      if (errno != EINVAL)
	result = 1;
      printf ("clock_gettime on reaped PID %d clock %lx => %s\n",
	      child, (unsigned long int) child_clock, strerror (errno));
    }

  if (clock_getres (child_clock, &dead) == 0)
    {
      printf ("clock_getres on reaped PID %d clock %lx => %ju%.9ju\n",
	      child, (unsigned long int) child_clock,
	      (uintmax_t) dead.tv_sec, (uintmax_t) dead.tv_nsec);
      result = 1;
    }
  else
    {
      if (errno != EINVAL)
	result = 1;
      printf ("clock_getres on reaped PID %d clock %lx => %s\n",
	      child, (unsigned long int) child_clock, strerror (errno));
    }

  return result;

 done:
  {
    if (kill (child, SIGKILL) != 0 && errno != ESRCH)
      {
	perror ("kill");
	return 2;
      }
    int x;
    if (waitpid (child, &x, 0) != child && errno != ECHILD)
      {
	perror ("waitpid");
	return 2;
      }
  }

  return result;
}


#define TIMEOUT 5
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"