Linux Cross Reference
cvs/emstar/fusd/test/openrace2.c

   /*
    *
    * Copyright (c) 2003 The Regents of the University of California.  All 
    * rights reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    *
   * - Redistributions of source code must retain the above copyright
   *   notice, this list of conditions and the following disclaimer.
   *
   * - Neither the name of the University 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 REGENTS 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 REGENTS 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.
   *
   */
   
  
  /*
   *
   * openrace.c: A test program as part of FUSD.
   *
   * This regression test program tries to exercise the FUSD race
   * condition between a device provider closing (and unregistering a
   * device), and clients trying to open that device.
   *
   * It should run for less than 30 seconds, then exit, saying ALL TESTS
   * PASSED.  If it freezes, or processes get stuck in the D state, or
   * you end up with zombie devices (in /dev/fusd/status), then there is
   * a problem.
   *
   * $Id: openrace2.c,v 1.4 2004-04-28 18:40:07 girod Exp $
   */
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <errno.h>
  #include <sys/wait.h>
  #include <signal.h>
  #include <string.h>
  
  #include "fusd.h"
  
  #define DEVNAME "/dev/testfusd/openrace"
  
  
  #define FORK \
    tmp = fork(); \
    if (tmp < 0) { perror("can't fork"); exit(1); } \
    if (tmp == 0)
  
  #define ITERATIONS 1000
  #define MAX_BEFORE_EXIT ((n/2) * ITERATIONS)
  
  int n;
  
  void done(int signo)
  {
    static int num_done = 0;
    int status;
    pid_t pid;
  
    while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
      printf("pid [%d] done\n", pid);
      num_done++;
    }
  
    /* if all N clients, plus the server, are done... we're done */
    if (num_done == n+1) {
      printf("test complete\n");
      exit(0);
    }
  }
  
  int _open(struct fusd_file_info *file)
  {
    static int count = 0;
  
    /* exit abruptly in the middle of the request stream */
    if (count++ >= MAX_BEFORE_EXIT)
      exit(1);
  
    return -ENOMEM;
  }
 
 int _close(struct fusd_file_info *file)
 {
   return 0;
 }
 
 
 int main(int argc, char *argv[])
 {
   int tmp, i;
 
   if (argc != 2 || (n = atoi(argv[1])) <= 0) {
     fprintf(stderr, "usage: %s <number-of-clients> (use at least 10 or 20)\n", argv[0]);
     exit(0);
   }
 
   printf("master is pid %d\n", getpid());
   signal(SIGCHLD, done);
 
   /* fork server */
   FORK {
     fusd_file_operations_t
       fops = {
         open: _open, 
         close: _close
       };
 
     if (fusd_register(DEVNAME, 0666, 0, &fops) < 0) {
       perror("Register failed");
       exit(1);
     } 
     printf("server is pid %d, will respond to %d before exiting\n",
            getpid(), MAX_BEFORE_EXIT);
     fusd_run();
   }
 
   sleep(1);
 
   for (i = 0; i < n; i++) {
     FORK {
       int j;
       int enomem=0, enoent=0, epipe=0, eother=0;
 
       printf("launched client %d, pid %d\n", i, getpid());
 
       for (j = 0; j < ITERATIONS; j++) {
         open(DEVNAME, O_RDWR);
 
         switch (errno) {
         case ENOMEM:
           enomem++;
           break;
         case ENOENT:
           enoent++;
           break;
         case EPIPE:
           epipe++;
           break;
         default:
           eother++;
           printf("[%d] got strange retval %d (%m)\n", getpid(), errno);
           break;
         }
       }
 
       printf("[%d] done; %d nomem, %d noent, %d pipe, %d other\n", getpid(),
              enomem, enoent, epipe, eother);
       exit(0);
     }
   }
 
   /* parent: wait for children to all exit */
   while (1)
     pause();
 }