src/test/async_signal_syscalls.c

/* -*- Mode: C; tab-width: 8; c-basic-offset: 2; indent-tabs-mode: nil; -*- */

#include "util.h"

static sig_atomic_t caught_usr1;

static void handle_usr1(int sig) {
  test_assert(SIGUSR1 == sig);
  atomic_puts("caught usr1");
  caught_usr1 = 1;
}

static void* do_thread(__attribute__((unused)) void* p) {
  while (1) {
    sched_yield();
  }
  return NULL;
}

int main(int argc, char* argv[]) {
  struct timespec ts;
  struct timeval tv;
  int num_its;
  int i;
  pthread_t thread;

  /* Create an extra thread so context switches can happen
     and SCHED events will be recorded. */
  pthread_create(&thread, NULL, do_thread, NULL);

  test_assert(argc == 2);
  num_its = atoi(argv[1]);
  test_assert(num_its > 0);

  atomic_printf("Running 2^%d iterations\n", num_its);

  signal(SIGUSR1, handle_usr1);

  atomic_puts("ready\n");

  /* Driver scripts choose the number of iterations based on
   * their needs. */
  for (i = 0; i < 1 << num_its; ++i) {
    /* The odds of the signal being caught in the library
     * implementing these syscalls is very high.  But even
     * if it's not caught there, this test will pass. */
    clock_gettime(CLOCK_MONOTONIC, &ts);
    gettimeofday(&tv, NULL);
    clock_gettime(CLOCK_MONOTONIC, &ts);
    gettimeofday(&tv, NULL);
    clock_gettime(CLOCK_MONOTONIC, &ts);
    gettimeofday(&tv, NULL);
    clock_gettime(CLOCK_MONOTONIC, &ts);
    gettimeofday(&tv, NULL);
    if (caught_usr1) {
      break;
    }
  }

  atomic_puts("EXIT-SUCCESS");
  return 0;
}