rt/tst-cpuclock1.c

   1 /* Test program for process CPU clocks.
   2    Copyright (C) 2004, 2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <time.h>
  22 #include <unistd.h>
  23 #include <fcntl.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <signal.h>
  27 #include <sys/wait.h>
  28
  29 /* This function is intended to rack up both user and system time.  */
  30 static void
  31 chew_cpu (void)
  32 {
  33   while (1)
  34     {
  35       static volatile char buf[4096];
  36       for (int i = 0; i < 100; ++i)
  37         for (size_t j = 0; j < sizeof buf; ++j)
  38           buf[j] = 0xaa;
  39       int nullfd = open ("/dev/null", O_WRONLY);
  40       for (int i = 0; i < 100; ++i)
  41         for (size_t j = 0; j < sizeof buf; ++j)
  42           buf[j] = 0xbb;
  43       write (nullfd, (char *) buf, sizeof buf);
  44       close (nullfd);
  45       if (getppid () == 1)
  46         _exit (2);
  47     }
  48 }
  49
  50 static int
  51 do_test (void)
  52 {
  53   int result = 0;
  54   clockid_t cl;
  55   int e;
  56   pid_t dead_child, child;
  57
  58   /* Fork a child and let it die, to give us a PID known not be valid
  59      (assuming PIDs don't wrap around during the test).  */
  60   {
  61     dead_child = fork ();
  62     if (dead_child == 0)
  63       _exit (0);
  64     if (dead_child < 0)
  65       {
  66         perror ("fork");
  67         return 1;
  68       }
  69     int x;
  70     if (wait (&x) != dead_child)
  71       {
  72         perror ("wait");
  73         return 2;
  74       }
  75   }
  76
  77   /* POSIX says we should get ESRCH for this.  */
  78   e = clock_getcpuclockid (dead_child, &cl);
  79   if (e != ENOSYS && e != ESRCH && e != EPERM)
  80     {
  81       printf ("clock_getcpuclockid on dead PID %d => %s\n",
  82               dead_child, strerror (e));
  83       result = 1;
  84     }
  85
  86   /* Now give us a live child eating up CPU time.  */
  87   child = fork ();
  88   if (child == 0)
  89     {
  90       chew_cpu ();
  91       _exit (1);
  92     }
  93   if (child < 0)
  94     {
  95       perror ("fork");
  96       return 1;
  97     }
  98
  99   e = clock_getcpuclockid (child, &cl);
 100   if (e == EPERM)
 101     {
 102       puts ("clock_getcpuclockid does not support other processes");
 103       goto done;
 104     }
 105   if (e != 0)
 106     {
 107       printf ("clock_getcpuclockid on live PID %d => %s\n",
 108               child, strerror (e));
 109       result = 1;
 110       goto done;
 111     }
 112
 113   const clockid_t child_clock = cl;
 114   struct timespec res;
 115   if (clock_getres (child_clock, &res) < 0)
 116     {
 117       printf ("clock_getres on live PID %d clock %lx => %s\n",
 118               child, (unsigned long int) child_clock, strerror (errno));
 119       result = 1;
 120       goto done;
 121     }
 122   printf ("live PID %d clock %lx resolution %lu.%.9lu\n",
 123           child, (unsigned long int) child_clock, res.tv_sec, res.tv_nsec);
 124
 125   struct timespec before, after;
 126   if (clock_gettime (child_clock, &before) < 0)
 127     {
 128       printf ("clock_gettime on live PID %d clock %lx => %s\n",
 129               child, (unsigned long int) child_clock, strerror (errno));
 130       result = 1;
 131       goto done;
 132     }
 133   /* Should be close to 0.0.  */
 134   printf ("live PID %d before sleep => %lu.%.9lu\n",
 135           child, before.tv_sec, before.tv_nsec);
 136
 137   struct timespec sleeptime = { .tv_nsec = 500000000 };
 138   if (nanosleep (&sleeptime, NULL) != 0)
 139     {
 140       perror ("nanosleep");
 141       result = 1;
 142       goto done;
 143     }
 144
 145   if (clock_gettime (child_clock, &after) < 0)
 146     {
 147       printf ("clock_gettime on live PID %d clock %lx => %s\n",
 148               child, (unsigned long int) child_clock, strerror (errno));
 149       result = 1;
 150       goto done;
 151     }
 152   /* Should be close to 0.5.  */
 153   printf ("live PID %d after sleep => %lu.%.9lu\n",
 154           child, after.tv_sec, after.tv_nsec);
 155
 156   struct timespec diff = { .tv_sec = after.tv_sec - before.tv_sec,
 157                            .tv_nsec = after.tv_nsec - before.tv_nsec };
 158   if (diff.tv_nsec < 0)
 159     {
 160       --diff.tv_sec;
 161       diff.tv_nsec += 1000000000;
 162     }
 163   if (diff.tv_sec != 0
 164       || diff.tv_nsec > 600000000
 165       || diff.tv_nsec < 100000000)
 166     {
 167       printf ("before - after %lu.%.9lu outside reasonable range\n",
 168               diff.tv_sec, diff.tv_nsec);
 169       result = 1;
 170     }
 171
 172   sleeptime.tv_nsec = 100000000;
 173   e = clock_nanosleep (child_clock, 0, &sleeptime, NULL);
 174   if (e == EINVAL || e == ENOTSUP || e == ENOSYS)
 175     {
 176       printf ("clock_nanosleep not supported for other process clock: %s\n",
 177               strerror (e));
 178     }
 179   else if (e != 0)
 180     {
 181       printf ("clock_nanosleep on other process clock: %s\n", strerror (e));
 182       result = 1;
 183     }
 184   else
 185     {
 186       struct timespec afterns;
 187       if (clock_gettime (child_clock, &afterns) < 0)
 188         {
 189           printf ("clock_gettime on live PID %d clock %lx => %s\n",
 190                   child, (unsigned long int) child_clock, strerror (errno));
 191           result = 1;
 192         }
 193       else
 194         {
 195           struct timespec d = { .tv_sec = afterns.tv_sec - after.tv_sec,
 196                                 .tv_nsec = afterns.tv_nsec - after.tv_nsec };
 197           if (d.tv_nsec < 0)
 198             {
 199               --d.tv_sec;
 200               d.tv_nsec += 1000000000;
 201             }
 202           if (d.tv_sec > 0
 203               || d.tv_nsec < sleeptime.tv_nsec
 204               || d.tv_nsec > sleeptime.tv_nsec * 2)
 205             {
 206               printf ("nanosleep time %lu.%.9lu outside reasonable range\n",
 207                       d.tv_sec, d.tv_nsec);
 208               result = 1;
 209             }
 210         }
 211     }
 212
 213   if (kill (child, SIGKILL) != 0)
 214     {
 215       perror ("kill");
 216       result = 2;
 217       goto done;
 218     }
 219
 220   /* Wait long enough to let the child finish dying.  */
 221
 222   sleeptime.tv_nsec = 200000000;
 223   if (nanosleep (&sleeptime, NULL) != 0)
 224     {
 225       perror ("nanosleep");
 226       result = 1;
 227       goto done;
 228     }
 229
 230   struct timespec dead;
 231   if (clock_gettime (child_clock, &dead) < 0)
 232     {
 233       printf ("clock_gettime on dead PID %d clock %lx => %s\n",
 234               child, (unsigned long int) child_clock, strerror (errno));
 235       result = 1;
 236       goto done;
 237     }
 238   /* Should be close to 0.6.  */
 239   printf ("dead PID %d => %lu.%.9lu\n",
 240           child, dead.tv_sec, dead.tv_nsec);
 241
 242   diff.tv_sec = dead.tv_sec - after.tv_sec;
 243   diff.tv_nsec = dead.tv_nsec - after.tv_nsec;
 244   if (diff.tv_nsec < 0)
 245     {
 246       --diff.tv_sec;
 247       diff.tv_nsec += 1000000000;
 248     }
 249   if (diff.tv_sec != 0 || diff.tv_nsec > 200000000)
 250     {
 251       printf ("dead - after %lu.%.9lu outside reasonable range\n",
 252               diff.tv_sec, diff.tv_nsec);
 253       result = 1;
 254     }
 255
 256   /* Now reap the child and verify that its clock is no longer valid.  */
 257   {
 258     int x;
 259     if (waitpid (child, &x, 0) != child)
 260       {
 261         perror ("waitpid");
 262         result = 1;
 263       }
 264   }
 265
 266   if (clock_gettime (child_clock, &dead) == 0)
 267     {
 268       printf ("clock_gettime on reaped PID %d clock %lx => %lu%.9lu\n",
 269               child, (unsigned long int) child_clock,
 270               dead.tv_sec, dead.tv_nsec);
 271       result = 1;
 272     }
 273   else
 274     {
 275       if (errno != EINVAL)
 276         result = 1;
 277       printf ("clock_gettime on reaped PID %d clock %lx => %s\n",
 278               child, (unsigned long int) child_clock, strerror (errno));
 279     }
 280
 281   if (clock_getres (child_clock, &dead) == 0)
 282     {
 283       printf ("clock_getres on reaped PID %d clock %lx => %lu%.9lu\n",
 284               child, (unsigned long int) child_clock,
 285               dead.tv_sec, dead.tv_nsec);
 286       result = 1;
 287     }
 288   else
 289     {
 290       if (errno != EINVAL)
 291         result = 1;
 292       printf ("clock_getres on reaped PID %d clock %lx => %s\n",
 293               child, (unsigned long int) child_clock, strerror (errno));
 294     }
 295
 296   return result;
 297
 298  done:
 299   {
 300     if (kill (child, SIGKILL) != 0 && errno != ESRCH)
 301       {
 302         perror ("kill");
 303         return 2;
 304       }
 305     int x;
 306     if (waitpid (child, &x, 0) != child && errno != ECHILD)
 307       {
 308         perror ("waitpid");
 309         return 2;
 310       }
 311   }
 312
 313   return result;
 314 }
 315
 316
 317 #define TIMEOUT 5
 318 #define TEST_FUNCTION do_test ()
 319 #include "../test-skeleton.c"