/* $Id: fifo_xu.c,v 1.3 2012/08/04 21:06:01 kostik Exp kostik $ */

#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define FIFO "myfifo"
#define BIGDATASIZE (1024 * 1024 * 16)

sig_atomic_t got_sigpipe;

static void
handler(int sig)
{

	got_sigpipe = 1;
}

static void
xerr(const char *fmt, ...)
{
	va_list ap;
	int err;

	err = errno;
	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	fprintf(stderr, ": %s", strerror(err));
	exit(1);
}

int
main(void)
{
	char *pbuf, buf[512];
	struct sigaction sa;
	pid_t pid;
	int errn, fd, ret;

	if (unlink(FIFO) == -1 && errno != ENOENT)
		xerr("unlink");
	if (mkfifo(FIFO, 0664) == -1)
		xerr("mkfifo");

	pid = fork();
	if (pid == 0) {
		fd = open(FIFO, O_RDONLY);
		if (fd == -1)
			xerr("child: can not open %s", FIFO);
		ret = read(fd, buf, sizeof(buf));
		printf("child: read %d bytes\n", ret);
		close(fd);
		return (0);
	}

	/* parent */
	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = handler;
	if (sigaction(SIGPIPE, &sa, NULL) == -1)
		xerr("sigaction");
	fd = open(FIFO, O_WRONLY);
	if (fd == -1)
		xerr("parent: can not open %s", FIFO);
	
	pbuf = malloc(BIGDATASIZE);
	got_sigpipe = 0;
	ret = write(fd, pbuf, BIGDATASIZE);
	errn = errno;
	printf("parent: first write return %d sigpipe %d", ret, got_sigpipe);
	if (ret == -1)
		printf(" error %d %s", errn, strerror(errn));
	putchar('\n');
	got_sigpipe = 0;
	ret = write(fd, pbuf, BIGDATASIZE);	
	errn = errno;
	printf("parent: second write return %d sigpipe %d", ret, got_sigpipe);
	if (ret == -1)
		printf(" error %d %s", errn, strerror(errn));
	putchar('\n');
	return (0);
}