text: /****************************************************************************
   * apps/testing/ostest/signest.c
   *
   *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <sys/types.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <semaphore.h>
  #include <signal.h>
  #include <sched.h>
  #include <errno.h>
  #include "ostest.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  #ifndef NULL
  # define NULL (void*)0
  #endif
  
  #define WAKEUP_SIGNAL 17
  #define SIGVALUE_INT  42
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  static sem_t g_waiter_sem;
  static sem_t g_interferer_sem;
  static volatile bool g_waiter_running;
  static volatile bool g_interferer_running;
  static volatile bool g_done;
  static volatile int g_nestlevel;
  
  static volatile int g_even_handled;
  static volatile int g_odd_handled;
  static volatile int g_even_nested;
  static volatile int g_odd_nested;
  
  static volatile int g_nest_level;
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  static bool signest_catchable(int signo)
  {
  #ifdef CONFIG_SIG_SIGSTOP_ACTION
    if (signo == SIGSTOP || signo == SIGCONT)
      {
        return false;
      }
  #endif
  
  #ifdef CONFIG_SIG_SIGKILL_ACTION
    if (signo == SIGKILL)
      {
        return false;
      }
  #endif
  
    return true;
  }
  
  static void waiter_action(int signo)
  {
    int nest_level;
  
    sched_lock();
    nest_level = g_nest_level++;
    sched_unlock();
  
    if ((signo & 1) != 0)
      {
        g_odd_handled++;
        if (nest_level > 0)
          {
            g_odd_nested++;
          }
      }
    else
      {
        g_even_handled++;
        if (nest_level > 0)
          {
            g_even_nested++;
          }
      }
  
    g_nest_level = nest_level;
  }
  
  static int waiter_main(int argc, char *argv[])
  {
    sigset_t set;
    struct sigaction act;
    int ret;
    int i;
  
    printf("waiter_main: Waiter started\n");
    printf("waiter_main: Setting signal mask\n");
  
    sigemptyset(&set);
    ret = sigprocmask(SIG_SETMASK, &set, NULL);
    if (ret < 0)
      {
        printf("waiter_main: ERROR sigprocmask failed: %d\n", errno);
        return EXIT_FAILURE;
      }
  
    printf("waiter_main: Registering signal handler\n");
  
    act.sa_handler = waiter_action;
    act.sa_flags   = 0;
  
    sigemptyset(&act.sa_mask);
    for (i = 1; i < MAX_SIGNO; i += 2)
      {
        if (signest_catchable(i))
          {
            sigaddset(&act.sa_mask, i);
          }
      }
  
    for (i = 1; i < MAX_SIGNO; i++)
      {
        if (signest_catchable(i))
          {
            ret = sigaction(i, &act, NULL);
            if (ret < 0)
              {
                printf("waiter_main: WARNING sigaction failed with %d\n",
                       errno);
                return EXIT_FAILURE;
              }
          }
      }
  
    /* Now just loop until the test completes */
  
    printf("waiter_main: Waiting on semaphore\n");
    FFLUSH();
  
    g_waiter_running = true;
    while (!g_done)
      {
        ret = sem_wait(&g_waiter_sem);
      }
  
    /* Just exit, the system should clean up the signal handlers */
  
    g_waiter_running = false;
    return EXIT_SUCCESS;
  }
  
  static int interfere_main(int argc, char *argv[])
  {
    /* Now just loop staying in the way as much as possible */
  
    printf("interfere_main: Waiting on semaphore\n");
    FFLUSH();
  
    g_interferer_running = true;
    while (!g_done)
      {
        sem_wait(&g_interferer_sem);
      }
  
    /* Just exit, the system should clean up the signal handlers */
  
    g_interferer_running = false;
    return EXIT_SUCCESS;
  }
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  void signest_test(void)
  {
    struct sched_param param;
    pid_t waiterpid;
    pid_t interferepid;
    int total_signals;
    int total_handled;
    int total_nested;
    int even_signals;
    int odd_signals;
    int prio;
    int ret;
    int i;
    int j;
  
    sem_init(&g_waiter_sem, 0, 0);
    sem_init(&g_interferer_sem, 0, 0);
    g_waiter_running = false;
    g_interferer_running = false;
    g_done = false;
    g_nestlevel = 0;
  
    even_signals = 0;
    odd_signals = 0;
  
    g_even_handled = 0;
    g_odd_handled = 0;
    g_even_nested = 0;
    g_odd_nested = 0;
  
    g_nest_level = 0;
  
    ret = sched_getparam (0, &param);
    if (ret < 0)
      {
        printf("signest_test: ERROR sched_getparam() failed\n");
        param.sched_priority = PTHREAD_DEFAULT_PRIORITY;
      }
  
    /* Start waiter thread  */
  
    prio = param.sched_priority + 1;
    printf("signest_test: Starting signal waiter task at priority %d\n", prio);
    waiterpid = task_create("waiter", param.sched_priority,
                             STACKSIZE, waiter_main, NULL);
    if (waiterpid == ERROR)
      {
        printf("signest_test: ERROR failed to start waiter_main\n");
        return;
      }
  
    printf("signest_test: Started waiter_main pid=%d\n", waiterpid);
  
    /* Start interfering thread  */
  
    prio++;
    printf("signest_test: Starting interfering task at priority %d\n", prio);
    interferepid = task_create("interfere", param.sched_priority,
                             STACKSIZE, interfere_main, NULL);
    if (interferepid == ERROR)
      {
        printf("signest_test: ERROR failed to start interfere_main\n");
        goto errout_with_waiter;
      }
  
    printf("signest_test: Started interfere_main pid=%d\n", interferepid);
  
    /* Wait a bit */
  
    FFLUSH();
    usleep(500 * 1000L);
  
    /* Then signal the waiter thread with back-to-back signals, one masked
     * and the other unmasked.
     */
  
    for (i = 0; i < 10; i++)
      {
        for (j = 1; j < MAX_SIGNO; j += 2)
          {
            if (signest_catchable(j))
              {
                kill(waiterpid, j);
                odd_signals++;
              }
  
            if (signest_catchable(j + 1))
              {
                kill(waiterpid, j + 1);
                even_signals++;
              }
  
            usleep(10 * 1000L);
  
            /* Even then odd */
  
            if (signest_catchable(j + 1))
              {
                kill(waiterpid, j + 1);
                even_signals++;
              }
  
            if (signest_catchable(j))
              {
                kill(waiterpid, j);
                odd_signals++;
              }
  
            usleep(10 * 1000L);
          }
      }
  
    /* Check the test results so far */
  
    total_signals = odd_signals + even_signals;
    total_handled = g_odd_handled + g_even_handled;
    total_nested  = g_odd_nested + g_even_nested;
  
    printf("signest_test: Simple case:\n");
    printf("  Total signalled %-3d  Odd=%-3d Even=%-3d\n",
           total_signals, odd_signals, even_signals);
    printf("  Total handled   %-3d  Odd=%-3d Even=%-3d\n",
           total_handled, g_odd_handled, g_even_handled);
    printf("  Total nested    %-3d  Odd=%-3d Even=%-3d\n",
           total_nested, g_odd_nested, g_even_nested);
  
    /* Then signal the waiter thread with two signals pending.  The
     * sched_lock() assures that the first signal was not processed
     * before the second was delivered.
     */
  
    for (i = 0; i < 10; i++)
      {
        for (j = 1; j < MAX_SIGNO; j += 2)
          {
            /* Odd then even */
  
            sched_lock();
  
            if (signest_catchable(j))
              {
                kill(waiterpid, j);
                odd_signals++;
              }
  
            if (signest_catchable(j + 1))
              {
                kill(waiterpid, j + 1);
                even_signals++;
              }
  
            sched_unlock();
  
            usleep(10 * 1000L);
  
            /* Even then odd */
  
            sched_lock();
  
            if (signest_catchable(j + 1))
              {
                kill(waiterpid, j + 1);
                even_signals++;
              }
  
            if (signest_catchable(j))
              {
                kill(waiterpid, j);
                odd_signals++;
              }
  
            sched_unlock();
  
            usleep(10 * 1000L);
          }
      }
  
    /* Check the test results so far */
  
    total_signals = odd_signals + even_signals;
    total_handled = g_odd_handled + g_even_handled;
    total_nested  = g_odd_nested + g_even_nested;
  
    printf("signest_test: With task locking\n");
    printf("  Total signalled %-3d  Odd=%-3d Even=%-3d\n",
           total_signals, odd_signals, even_signals);
    printf("  Total handled   %-3d  Odd=%-3d Even=%-3d\n",
           total_handled, g_odd_handled, g_even_handled);
    printf("  Total nested    %-3d  Odd=%-3d Even=%-3d\n",
           total_nested, g_odd_nested, g_even_nested);
  
    /* Then do it all over again with the interfering thread. */
  
    for (i = 0; i < 10; i++)
      {
        for (j = 1; j < MAX_SIGNO; j += 2)
          {
            /* Odd then even */
  
            sched_lock();
  
            if (signest_catchable(j))
              {
                kill(waiterpid, j);
                odd_signals++;
              }
  
            sem_post(&g_interferer_sem);
  
            if (signest_catchable(j + 1))
              {
                kill(waiterpid, j + 1);
                even_signals++;
              }
  
            sched_unlock();
  
            usleep(10 * 1000L);
  
            /* Even then odd */
  
            sched_lock();
            if (signest_catchable(j + 1))
              {
                kill(waiterpid, j + 1);
                even_signals++;
              }
  
            sem_post(&g_interferer_sem);
  
            if (signest_catchable(j))
              {
                kill(waiterpid, j);
                odd_signals++;
              }
  
            sched_unlock();
  
            usleep(10 * 1000L);
          }
      }
  
    /* Stop the threads */
  
  errout_with_waiter:
    g_done = true;
    sem_post(&g_waiter_sem);
    sem_post(&g_interferer_sem);
    usleep(500 * 1000L);
  
    /* Check the final test results */
  
    total_signals = odd_signals + even_signals;
    total_handled = g_odd_handled + g_even_handled;
    total_nested  = g_odd_nested + g_even_nested;
  
    printf("signest_test: With intefering thread\n");
    printf("  Total signalled %-3d  Odd=%-3d Even=%-3d\n",
           total_signals, odd_signals, even_signals);
    printf("  Total handled   %-3d  Odd=%-3d Even=%-3d\n",
           total_handled, g_odd_handled, g_even_handled);
    printf("  Total nested    %-3d  Odd=%-3d Even=%-3d\n",
           total_nested, g_odd_nested, g_even_nested);
  
    /* Check for error */
  
    if (g_waiter_running)
      {
        printf("signest_test: ERROR waiter is still running\n");
      }
  
    if (g_interferer_running)
      {
        printf("signest_test: ERROR interferer is still running\n");
      }
  
    if (total_signals != total_handled)
      {
        printf("signest_test: ERROR only %d of %d signals were handled\n",
               total_handled, total_signals);
      }
  
    if (odd_signals != g_odd_handled)
      {
        printf("signest_test: ERROR only %d of %d ODD signals were handled\n",
               g_odd_handled, odd_signals);
      }
  
    if (even_signals != g_even_handled)
      {
        printf("signest_test: ERROR only %d of %d EVEN signals were handled\n",
               g_even_handled, even_signals);
      }
  
    if (g_odd_nested > 0)
      {
        printf("signest_test: ERROR %d ODD signals were nested\n",
               g_odd_nested);
      }
  
    sem_destroy(&g_waiter_sem);
    sem_destroy(&g_interferer_sem);
  
    printf("signest_test: done\n");
    FFLUSH();
  }
  