/* Test program for process CPU clocks. Copyright (C) 2004-2024 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 <https://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> #include <support/xunistd.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; xwrite (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; 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 = 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 { printf ("live PID %d after sleep => %ju.%.9ju\n", child, (uintmax_t) afterns.tv_sec, (uintmax_t) afterns.tv_nsec); } } 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 0.1. */ printf ("dead PID %d => %ju.%.9ju\n", child, (uintmax_t) dead.tv_sec, (uintmax_t) dead.tv_nsec); /* 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 TEST_FUNCTION do_test () #include "../test-skeleton.c"