tree b3b0e1c2f4eafbfe92e64a0df5eed11aae8d7e5b
parent c23122808577dca6315f3fc3b6cc4ef67e877080
author Brad Fitzpatrick <bradfitz@golang.org> 1429220005 -0700
committer Brad Fitzpatrick <bradfitz@golang.org> 1429757323 +0000

net: use Go's DNS resolver when system configuration permits

If the machine's network configuration files (resolv.conf,
nsswitch.conf) don't have any unsupported options, prefer Go's DNS
resolver, which doesn't have the cgo & thread over.

It means users can have more than 500 DNS requests outstanding (our
current limit for cgo lookups) and not have one blocked thread per
outstanding request.

Discussed in thread https://groups.google.com/d/msg/golang-dev/2ZUi792oztM/Q0rg_DkF5HMJ

Change-Id: I3f685d70aff6b47bec30b63e9fba674b20507f95
Reviewed-on: https://go-review.googlesource.com/8945
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>