/*
 * Copyright 2007, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * Copyright 2002, Manuel J. Petit. All rights reserved.
 * Distributed under the terms of the NewOS License.
 */


#include <image.h>

#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>


int gForked = 0;


static void
usage(char const *app)
{
        printf("usage: %s ###\n", app);
        exit(-1);
}


int
main(int argc, char *argv[])
{
        int result = 0;

        if (argc != 2)
                usage(argv[0]);

        int num = atoi(argv[1]);

        if (num < 2) {
                result = num;
        } else {
                pid_t childA = fork();
                if (childA == 0) {
                        // we're the child
                        char buffer[64];
                        char* args[]= { argv[0], buffer, NULL };
                        int argCount = 2;
                        gForked++;

                        snprintf(buffer, sizeof(buffer), "%d", num - 1);
                        return main(argCount, args);
                } else if (childA < 0) {
                        fprintf(stderr, "fork() failed for child A: %s\n", strerror(errno));
                        return -1;
                }

                pid_t childB = fork();
                if (childB == 0) {
                        // we're the child
                        char buffer[64];
                        char* args[]= { argv[0], buffer, NULL };
                        int argCount = 2;
                        gForked++;

                        snprintf(buffer, sizeof(buffer), "%d", num - 2);
                        return main(argCount, args);
                } else if (childB < 0) {
                        fprintf(stderr, "fork() failed for child B: %s\n", strerror(errno));
                        return -1;
                }

                status_t status, returnValue = 0;
                do {
                        status = wait_for_thread(childA, &returnValue);
                } while (status == B_INTERRUPTED);

                if (status == B_OK)
                        result = returnValue;
                else
                        fprintf(stderr, "wait_for_thread(%ld) A failed: %s\n", childA, strerror(status));

                do {
                        status = wait_for_thread(childB, &returnValue);
                } while (status == B_INTERRUPTED);

                if (status == B_OK)
                        result += returnValue;
                else
                        fprintf(stderr, "wait_for_thread(%ld) B failed: %s\n", childB, strerror(status));
        }

        if (gForked) {
                return result;
        } else {
                printf("%d\n", result);
                return 0;
        }
}