Rozwiązanie zadania 1_2B z SOP2

pipes.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/wait.h>
#include <string.h>
#include <time.h>
#include <limits.h>

#define ERR(source) (perror(source),\
                     fprintf(stderr,"%s:%d\n",__FILE__,__LINE__),\
                     exit(EXIT_FAILURE))

void usage(char*);
void create_children(int, int**, int);
void child_work(int**, int, int);
void parent_work(int**, int, int);

int main(int argc, char** argv) 
{
        if(argc!=3)
		usage(argv[0]);
        
        int n = atoi(argv[1]);
        int k = atoi(argv[2]);
        
        int** pipes;
        if((pipes = (int**)malloc(sizeof(int*)*(n+1))) == NULL)
			ERR("malloc pipes**\n");
        for(int i =0; i<n+1; i++)
	{
		if((pipes[i] = (int*)malloc(sizeof(int)*2))==NULL)
			ERR("malloc pipes*\n");
		pipe(pipes[i]);
	}
		
        create_children(n, pipes, k);
    
        return EXIT_SUCCESS;
}

void create_children(int n, int** pipes, int k)
{
	pid_t pid;
	printf("[%d](PARENT) - Process created\n", getpid());
	for(int i=1; i<n+1; i++)
    	{
		if((pid = fork())<(pid_t)0) ERR("fork failed\n");
		if(pid==0) //child
		{
			printf("[%d] - Process created\n", getpid());
			for(int j=1; j<n+1; j++)
			{
				if(j!=i)
				{
					//printf("[%d] - closing read_fd nr: [%d]\n", getpid(), j);
					close(pipes[j][0]);
				}
			}
			//printf("[%d] - closing write_fd nr: [%d]\n", getpid(), i);
			close(pipes[i][1]);
			child_work(pipes, i, n);
			break;
		}
		else //parent
		{
			//printf("[%d](PARENT) - closing read_fd nr: [%d]\n", getpid(), i);
			close(pipes[i][0]);
		}
	}
	if(pid!=0)//PARENT
	{
		//printf("[%d](PARENT) - closing write_fd nr: [%d]\n", getpid(), 0);
		close(pipes[0][1]);
		parent_work(pipes, n, k);
	}
}

void child_work(int **pipes, int id, int n)
{
	char message[PIPE_BUF], temp[3];
	memset(message, 0, sizeof(message));
	srand(getpid());
	int rand_id;
	
	while(1)
	{
		read(pipes[id][0], message, PIPE_BUF);
		if(0==strcmp(message, "[-]"))
			break;
		do
		{
			rand_id = rand()%(n+1);
		}while(rand_id==id);
		
		sprintf(temp, "%d ", id);
		strcat(message, temp);
		write(pipes[rand_id][1], message, PIPE_BUF);
	}
	
	printf("[%d] - Closing all left pipes\n", getpid());
	for(int i=0; i<n+1; i++)
	{
		if(i!=id)
			close(pipes[i][1]);
	}
	close(pipes[id][0]);
	printf("[%d] - Stopping process\n", getpid());
}

void parent_work(int** pipes, int n, int k)
{	
	int rand_id;
	char message[PIPE_BUF];
	
	for(int i=1; i<k+1; i++)
	{
		memset(message, 0, sizeof(message));
		sprintf(message, "[%d] 0 ", i);
		
		rand_id = (rand()%n)+1;
		write(pipes[rand_id][1], message, PIPE_BUF);
	
		read(pipes[0][0], message, PIPE_BUF);
		printf("Message: %s\n", message);	
	}

	memset(message, 0, sizeof(message));
	strcat(message, "[-]");
	for(int i =1; i<n+1; i++)
		write(pipes[i][1], message, PIPE_BUF);

	while(wait(NULL)>0);
	
	printf("[%d](PARENT) - Closing all left pipes\n", getpid());
	for(int i=1; i<n+1; i++)
		close(pipes[i][1]);
	close(pipes[0][0]);
	printf("[%d](PARENT) - Stopping process\n", getpid());
}

void usage(char *name)
{
        fprintf(stderr,"USAGE: n - number of processes, k - number of messages\n");
        exit(EXIT_FAILURE);
}