/* Tests for POSIX timer implementation using another process's CPU clock. */ #include <unistd.h> #if _POSIX_THREADS && defined _POSIX_CPUTIME #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <fcntl.h> #include <time.h> #include <signal.h> #include <sys/wait.h> static clockid_t child_clock; #define TEST_CLOCK child_clock #define TEST_CLOCK_MISSING(clock) \ (setup_test () ? "other-process CPU clock timer support" : NULL) /* 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 pid_t child; static void cleanup_child (void) { if (child <= 0) return; if (kill (child, SIGKILL) < 0 && errno != ESRCH) printf ("cannot kill child %d: %m\n", child); else { int status; errno = 0; if (waitpid (child, &status, 0) != child) printf ("waitpid %d: %m\n", child); } } #define CLEANUP_HANDLER cleanup_child () static int setup_test (void) { /* Test timers on a process CPU clock by having a child process eating CPU. First make sure we can make such timers at all. */ int pipefd[2]; if (pipe (pipefd) < 0) { printf ("pipe: %m\n"); exit (1); } child = fork (); if (child == 0) { char c; close (pipefd[1]); if (read (pipefd[0], &c, 1) == 1) chew_cpu (); _exit (1); } if (child < 0) { printf ("fork: %m\n"); exit (1); } atexit (&cleanup_child); close (pipefd[0]); int e = clock_getcpuclockid (child, &child_clock); if (e == EPERM) { puts ("clock_getcpuclockid does not support other processes"); return 1; } if (e != 0) { printf ("clock_getcpuclockid: %s\n", strerror (e)); exit (1); } timer_t t; if (timer_create (TEST_CLOCK, NULL, &t) != 0) { printf ("timer_create: %m\n"); return 1; } timer_delete (t); /* Get the child started chewing. */ if (write (pipefd[1], "x", 1) != 1) { printf ("write to pipe: %m\n"); return 1; } close (pipefd[1]); return 0; } #else # define TEST_CLOCK_MISSING(clock) "process clocks" #endif #include "tst-timer4.c"