net: Checking errors for EPIPE and ECONNRESET requires syscall

[PieterD]

Reading and writing can cause EPIPE and ECONNRESET to be returned in addition to io.EOF.

_, err := conn.Write(data)
if oe, ok := err.(*net.OpError); ok && (oe.Err == syscall.EPIPE || oe.Err ==
syscall.ECONNRESET) {
    return fmt.Errorf("Connection closed")
}

_, err := conn.Read(data)
oe, ok := err.(*net.OpError)
if err == io.EOF || ok && oe.Err == syscall.ECONNRESET {
    return fmt.Errorf("Connection closed")
}

This isn't the neatest solution, and if we're going to freeze and possibly internalize
syscall, this is going to have to go.

Perhaps something similar to os.IsExist? I'm thinking net.IsReset or net.IsClosed.

Or we could simply return io.EOF for both. I don't know.

And what about other operating systems? Do they have similar problems?

[ianlancetaylor]

Comment 1:

Labels changed: added repo-main, release-go1.4.

[rsc]

Comment 2:

Status changed to Thinking.

[rsc]

Comment 3:

I don't know what to do about this. 
We could use io.ErrUnexpectedEOF for Read, and maybe for Write too. Unclear.
I'm not thrilled about hacks in net because writing to pipes has the same problem.
But I'm not thrilled about hacks in os either.
Leaving for 1.5.

Labels changed: added release-go1.5, removed release-go1.4.

[bsed]

"readfull EOF:*net.OpError read tcp 172.19.13.222:51753->172.19.5.50:9091: wsarecv: An established connection was aborted by the software in your host machine.