fstat doesn't work on pipes

[hoodmane]

Consider the following simple program:

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdio.h>

int fd[2];

int main(){
    struct stat statbuf;
    pipe(fd);
    int status = fstat(fd[0], &statbuf);
    printf("status: %d\n", status);
	return status;
}

If I compile it with gcc and run it, it will print status: 0. If I compile it with emcc and run it with node, it will print status: -1.

[tiran]

NODERAWFS's fstat() does not seem to work on any fd that is not backed by a physical file on the file system. I also noticed that fstat() fails after the backing file is unlink()ed. python-wasm ticket emmatyping/python-wasm#66 has a reproducer in Python. Both issues could be related.