#define _GNU_SOURCE

#include <sys/socket.h>
#include <sys/types.h>

#include <fcntl.h>
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int sock_fd[2];
static int pipe_fd[2];

static void *do_file_to_pipe(void *unused)
{
	int splice_len = 3;

	while (1) {
		char filename[80];
		char command[80];
		int file_fd;

		sprintf(filename, "splice-%d-%d-%d", getpid(), pthread_self(), splice_len);
		sprintf(command, "dmesg > %s", filename);
		system(command);

		file_fd = open(filename, O_RDONLY);
		if (file_fd == -1)
			exit(EXIT_FAILURE);

		while (1) {
			int n;

			n = splice(file_fd, NULL, pipe_fd[1], NULL,
				splice_len, 0);
			if (n == -1)
				exit(EXIT_FAILURE);
			if (n == 0)
				break;
		}

		close(file_fd);

		sprintf(command, "rm %s", filename);
		system(command);

		splice_len += rand() % 512;
		if (splice_len >= 16384)
			splice_len -= 16384;
	}

	return NULL;
}

static void *do_pipe_to_sock(void *unused)
{
	int splice_len = 383;

	while (1) {
		if (splice(pipe_fd[0], NULL, sock_fd[1], NULL,
			splice_len, 0) == -1)
		{
			exit(EXIT_FAILURE);
		}

		splice_len += rand() % 512;
		if (splice_len >= 16384)
			splice_len -= 16384;
	}

	return NULL;
}

static void *do_sock_to_sock(void *unused)
{
	while (1) {
		unsigned int n;
		char *buf;

		n = rand() % 16384;
		buf = malloc(n);

		if (read(sock_fd[0], buf, n) == -1)
			exit(EXIT_FAILURE);

		free(buf);
	}
}

#define N_THREADS 3

int main(int argc, char *argv[])
{
	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sock_fd) == -1)
		exit(EXIT_FAILURE);

	if (pipe(pipe_fd) == -1)
		exit(EXIT_FAILURE);

	pthread_t file_to_pipe_thread[N_THREADS];
	pthread_t pipe_to_sock_thread[N_THREADS];
	pthread_t sock_to_sock_thread[N_THREADS];

	int i;
	for (i = 0; i < N_THREADS; ++i) {
		pthread_create(&file_to_pipe_thread[i], NULL,
				&do_file_to_pipe, NULL);
		pthread_create(&pipe_to_sock_thread[i], NULL,
				&do_pipe_to_sock, NULL);
		pthread_create(&sock_to_sock_thread[i], NULL,
				&do_sock_to_sock, NULL);
	}

	while (1)
		sleep(60);

	return EXIT_SUCCESS;
}