io::stdin().read(buf) hangs when stdin is pipe on Linux

[stepancheg]

Rust stdlib hangs instead of reporting EOF when stdin is pipe.

Testing with script:

echo aaa | ./program

C program, does not hang, exits properly:

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>

int main() {
    for (;;) {
        char buf[1];
        ssize_t r = read(STDIN_FILENO, buf, 1);
        if (r == 0) {
            break;
        } else if (r < 0) {
            perror("read");
            exit(1);
        } else {
            printf("%d\n", (int) buf[0]);
        }
    }
    return 0;
}

Rust program hangs on Linux, exits properly on OSX:

use std::rt::io::stdin;
use std::rt::io::Reader;

fn main() {
    let mut r = stdin();
    loop {
        let b = r.read_byte();
        if b.is_none() {
            break;
        }
        println!("{}", b.unwrap());
    }
}

[alexcrichton]

This appears to not be our problem, but rather joyent/libuv#982. We'll need to update libuv once that gets fixed.

[alexcrichton]

Hm, nevermind, I need to keep investigating.

[alexcrichton]

Ah, narrowed it down, looks like that libuv bug