ipc/shm_semaph_test.c

   1 /***************************************************************************
   2  * Copyright 1995, Technion, Israel Institute of Technology
   3  * Electrical Eng, Software Lab.
   4  * Author:    Michael Veksler.
   5  ***************************************************************************
   6  * File:      shm_semaph_test.c
   7  * Purpose:   Test semaphores handleingr shared memory operations.
   8  ***************************************************************************
   9  */
  10 #include <time.h>
  11 #include <stdio.h>
  12 #include <unistd.h>
  13 #include <errno.h>
  14 #include <stdlib.h>
  15 #include <sys/wait.h>
  16 #include "shm_semaph.h"
  17 #include <sys/shm.h>
  18 #define DEBUG_DEFINE_VARIABLES
  19 #include <debug.h>
  20
  21 static volatile int * volatile data;
  22 static int isparent=0;
  23 #define DELAY (rand()%10)
  24 shm_sem sem;
  25
  26 static void read_write(int num)
  27 {
  28   int i,j ;
  29   volatile float dummy=0;
  30   int val;
  31
  32   srand(num+time(NULL));
  33   for (i=0x3fff;i>=0;i--) {
  34      if((i&0x7ff)==0 && isparent)
  35         fprintf(stderr,"0x%06x\r",i);
  36      shm_write_wait(sem);
  37      *data= num;
  38      for (j=DELAY ; j>=0;j--)
  39         dummy*=2;
  40      if (*data!=num) {
  41         fprintf(stderr,"\nbad shm_write_wait(), num=%d\n",num);
  42         shm_write_signal(sem);
  43         return;
  44      }
  45      shm_write_signal(sem);
  46      for (j=DELAY ; j>=0 ;j--)
  47         dummy*=2;
  48      shm_read_wait(sem);
  49      val=*data;
  50      for (j=DELAY; j>=0 ;j--)
  51         dummy*=0.5;
  52      if (*data!=val) {
  53         fprintf(stderr,"\nbad shm_read_wait(), num=%d,val=%d,*data=%d\n",
  54                 num,val,*data);
  55         shm_read_signal(sem);
  56         return;
  57      }
  58      shm_read_signal(sem);
  59   }
  60   if (isparent)
  61      fputc('\n',stderr);
  62 }
  63 static void child1()
  64 {
  65   read_write(2);
  66 }
  67 static void child2()
  68 {
  69   read_write(10);
  70 }
  71 static void parent()
  72 {
  73   isparent=1;
  74   read_write(60);
  75 }
  76
  77 int main()
  78 {
  79   int shmid;
  80   int ret1, ret2;
  81   int pid1, pid2;
  82   int stat=0;
  83
  84   shm_sem_init(&sem);
  85   shmid=shmget(IPC_PRIVATE, 0x100, IPC_CREAT | 0700);
  86   data= (int *)shmat ( shmid, NULL, 0);
  87   *data=0;
  88
  89   switch (pid1=fork()) {
  90     case -1:
  91       perror("fork 1");
  92       return 1;
  93     case 0:
  94       fprintf(stderr,"child1\n");
  95       child1();
  96       fprintf(stderr,"child1 done\n");
  97       return 0;
  98     default :
  99   }
 100   switch (pid2=fork()) {
 101     case -1:
 102       perror("fork 2");
 103       stat|=1;
 104       break;
 105     case 0:
 106       fprintf(stderr,"child2\n");
 107       child2();
 108       fprintf(stderr,"child2 done\n");
 109       return 0;
 110     default :
 111   }
 112   fprintf(stderr,"parent\n");
 113   if (pid2>0) {                    /* if second fork did not fail */
 114      parent();
 115      fprintf(stderr,"parent done, waiting for child2\n");
 116      waitpid(pid2,&ret2,WUNTRACED);
 117      stat|=ret2;
 118   }
 119   fprintf(stderr,"parent done, waiting for child1\n");
 120   waitpid(pid1,&ret1,WUNTRACED);
 121   stat|=ret1;
 122   fprintf(stderr,"all done\n");
 123
 124   shmctl(shmid, IPC_RMID,NULL);
 125   shm_sem_done(&sem);
 126   return stat;
 127 }