/* ====================================================================
 * The Apache Software License, Version 1.1
 *
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 * reserved.
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 * modification, are permitted provided that the following conditions
 * are met:
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in
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 *    distribution.
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 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 5. Products derived from this software may not be called "Apache",
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

#include "apr_shmem.h"
#include "apr_lock.h"
#include "apr_errno.h"
#include "apr_general.h"
#include "apr_lib.h"
#include "apr_strings.h"
#include "apr_time.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif

typedef struct mbox {
    char msg[1024]; 
    int msgavail; 
} mbox;
apr_pool_t *context;
mbox *boxes;

static void msgwait(int boxnum)
{
    volatile int test = 0;
    while (test == 0) {
        apr_sleep(0);
        test = boxes[boxnum].msgavail;
    }    
    fprintf(stdout, "\nreceived a message in box %d, message was: %s\n", 
            boxnum, boxes[boxnum].msg); 
}

static void msgput(int boxnum, char *msg)
{
    fprintf(stdout, "Sending message to box %d\n", boxnum);
    apr_cpystrn(boxes[boxnum].msg, msg, strlen(msg));
    boxes[boxnum].msgavail = 1;
}

int main(void)
{
#if APR_HAS_SHARED_MEMORY
    apr_shmem_t *shm;
    pid_t pid;
    int size;

    apr_initialize();

    fprintf(stdout, "Initializing the context......."); 
    if (apr_pool_create(&context, NULL) != APR_SUCCESS) {
        fprintf(stderr, "could not initialize\n");
        exit(-1);
    }
    fprintf(stdout, "OK\n");

    fprintf(stdout, "Creating shared memory block......."); 
    if (apr_shm_init(&shm, 1048576, NULL, context) != APR_SUCCESS) { 
        fprintf(stderr, "Error allocating shared memory block\n");
        exit(-1);
    }
    fprintf(stdout, "OK\n");

    fprintf(stdout, "Allocating shared memory......."); 
    size = sizeof(mbox) * 2;
    boxes = apr_shm_calloc(shm, size);
    if (boxes == NULL) { 
        fprintf(stderr, "Error creating message boxes.\n");
        exit(-1);
    }
    fprintf(stdout, "OK\n");

    fprintf(stdout, "Creating a child process\n");
    pid = fork();
    if (pid == 0) {
        apr_sleep(1);
        if (apr_shm_open(shm) == APR_SUCCESS) {
            msgwait(1);
            msgput(0, "Msg received\n");
        } else {
            puts( "Child: unable to get access to shared memory" );
        }
        exit(1);
    }
    else if (pid > 0) {
        msgput(1, "Sending a message\n");
        apr_sleep(1);
        msgwait(0);
        exit(1);
    }
    else {
        fprintf(stderr, "Error creating a child process\n");
        exit(1);
    }
#else
    fprintf(stdout, "APR SHMEM test failed!\n");
    fprintf(stdout, "shmem is not supported on this platform\n"); 
    return (-1);
#endif
}