+#include <ccan/io/io.h>
+/* Include the C files directly. */
+#include <ccan/io/poll.c>
+#include <ccan/io/io.c>
+#include <ccan/tap/tap.h>
+#include <sys/wait.h>
+#include <stdio.h>
+
+#define PORT "65047"
+
+struct data {
+ struct io_listener *l;
+ char *pattern;
+ char buf[30];
+ size_t buflen;
+};
+
+static struct io_plan *read_more(struct io_conn *conn, struct data *d);
+static struct io_plan *write_more(struct io_conn *conn, struct data *d);
+
+static struct io_plan *read_done(struct io_conn *conn, struct data *d)
+{
+ tal_resize(&d->pattern, tal_count(d->pattern) + 1 + strlen(d->buf));
+ strcat(d->pattern, "<");
+ strcat(d->pattern, d->buf);
+ return read_more(conn, d);
+}
+
+static struct io_plan *read_more(struct io_conn *conn, struct data *d)
+{
+ memset(d->buf, 0, sizeof(d->buf));
+ return io_read_partial(conn, d->buf, sizeof(d->buf), &d->buflen,
+ read_done, d);
+}
+
+static struct io_plan *write_done(struct io_conn *conn, struct data *d)
+{
+ tal_resize(&d->pattern, tal_count(d->pattern) + 1);
+ strcat(d->pattern, ">");
+ return write_more(conn, d);
+}
+
+static struct io_plan *write_more(struct io_conn *conn, struct data *d)
+{
+ return io_write_partial(conn, d->buf, 1, &d->buflen,
+ write_done, d);
+}
+
+static struct io_plan *read_priority_init(struct io_conn *conn, struct data *d)
+{
+ /* This should suppress the write */
+ ok1(io_conn_exclusive(conn, true));
+ return read_more(conn, d);
+}
+
+static struct io_plan *init_conn(struct io_conn *conn, struct data *d)
+{
+ /* Free listener so when conns close we exit io_loop */
+ io_close_listener(d->l);
+
+ return io_duplex(conn, read_priority_init(conn, d), write_more(conn, d));
+}
+
+
+static int make_listen_fd(const char *port, struct addrinfo **info)
+{
+ int fd, on = 1;
+ struct addrinfo *addrinfo, hints;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = AF_UNSPEC;
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_flags = AI_PASSIVE;
+ hints.ai_protocol = 0;
+
+ if (getaddrinfo(NULL, port, &hints, &addrinfo) != 0)
+ return -1;
+
+ fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
+ addrinfo->ai_protocol);
+ if (fd < 0)
+ return -1;
+
+ setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+ if (bind(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) != 0) {
+ close(fd);
+ return -1;
+ }
+ if (listen(fd, 1) != 0) {
+ close(fd);
+ return -1;
+ }
+ *info = addrinfo;
+ return fd;
+}
+
+int main(void)
+{
+ struct addrinfo *addrinfo = NULL;
+ int fd, status;
+ struct data d;
+
+ /* This is how many tests you plan to run */
+ plan_tests(8);
+ fd = make_listen_fd(PORT, &addrinfo);
+ ok1(fd >= 0);
+ d.l = io_new_listener(NULL, fd, init_conn, &d);
+ ok1(d.l);
+ fflush(stdout);
+
+ if (!fork()) {
+ io_close_listener(d.l);
+ fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
+ addrinfo->ai_protocol);
+ if (fd < 0)
+ exit(1);
+ if (connect(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) != 0)
+ exit(2);
+ signal(SIGPIPE, SIG_IGN);
+
+ if (write(fd, "1hellothere", strlen("1hellothere")) != strlen("1hellothere"))
+ exit(3);
+ sleep(1);
+ if (write(fd, "1helloagain", strlen("1helloagain")) != strlen("1helloagain"))
+ exit(4);
+ close(fd);
+ freeaddrinfo(addrinfo);
+ exit(0);
+ }
+ freeaddrinfo(addrinfo);
+
+ d.pattern = tal_arrz(NULL, char, 1);
+ ok1(io_loop(NULL, NULL) == NULL);
+ /* No trace of writes */
+ ok1(strcmp(d.pattern, "<1hellothere<1helloagain") == 0);
+ tal_free(d.pattern);
+
+ ok1(wait(&status));
+ ok1(WIFEXITED(status));
+ ok1(WEXITSTATUS(status) == 0);
+
+ /* This exits depending on whether all tests passed */
+ return exit_status();
+}