Implementation of cat using splice()

splice_cat.c

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

int p[2];
const size_t sz = 65536;

void cat(int fd)
{
	ssize_t nb_read, nb_spliced;
	while ((nb_read = splice(fd, NULL, p[1], NULL, sz, SPLICE_F_MOVE)) > 0) {
		do {
			if ((nb_spliced = splice(p[0], NULL, STDOUT_FILENO, NULL, nb_read, SPLICE_F_MOVE)) < 0) {
				perror("splice");
				exit(EXIT_FAILURE);
			}
			nb_read -= nb_spliced;
		} while (nb_read > 0);
	}
	if (nb_read < 0) {
		perror("splice");
		exit(EXIT_FAILURE);
	}
}

int main(int argc, char **argv)
{
	if (pipe(p) < 0) {
		perror("pipe");
		exit(EXIT_FAILURE);
	}
	
	if (argc < 2) {
		cat(STDIN_FILENO);
		exit(EXIT_SUCCESS);
	}
	
	int i;
	int fd;
	for (i = 1; i < argc; i++) {
		if ((fd = open(argv[i], O_RDONLY)) < 0) {
			perror("open");
			exit(EXIT_FAILURE);
		}
		cat(fd);
		close(fd);
	}
	
	return 0;
}