Opening a named pipe hangs libuv

[haesbaert]

Luv.File.open_ on a named pipe hangs until there is input, this is not luv's fault, it's in libuv.
We're supposed to use uv_pipe_t on a named pipe, the manual explains it how, which means that if we want Path.open_in to work, we would have to first stat the file descriptor and do the uv_fs_t <> uv_pipe_t dance.

#include <stdio.h>
#include <stdlib.h>
#include <uv.h>
#include <unistd.h>
#include <err.h>

int
main(int argc, char *argv[])
{
	uv_loop_t *loop = uv_default_loop();
	uv_fs_t uv_fs_req;
	int fd;

	fd = uv_fs_open(loop, &uv_fs_req, argv[1], O_RDONLY, 0644, NULL);
	if (fd == -1)
		err(1, "uv_fs_open");
	printf("fd=%d\n", fd);

	printf("[%llu] running\n", (unsigned long long)getpid());
	uv_run(loop, UV_RUN_DEFAULT);

	uv_loop_close(loop);
	return (0);
}

cc -o uv_named_pipes uv_named_pipes.c -Wall -luv && file /tmp/sometext && ./uv_named_pipes /tmp/sometext
/tmp/sometext: ASCII text
fd=9
[3591398] running

 cc -o uv_named_pipes uv_named_pipes.c -Wall -luv && file /tmp/somepipe && ./uv_named_pipes /tmp/somepipe
/tmp/somepipe: fifo (named pipe)

[talex5]

This works with the replacement eio_posix backend.