[PATCH] freebsd: avoid EINVAL when setting accept filter

[Eric Wong <e@80x24.org>]

Accept filters can only be set on listen sockets, and it also
fails with EINVAL if it's already set.

Untested, but I suppose changing the accept filter on a listening
socket is not supported, either; since that could affect in-flight
sockets.
---
 lib/unicorn/socket_helper.rb | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/unicorn/socket_helper.rb b/lib/unicorn/socket_helper.rb
index df8315e..7aa2bb0 100644
--- a/lib/unicorn/socket_helper.rb
+++ b/lib/unicorn/socket_helper.rb
@@ -63,12 +63,15 @@ def set_tcp_sockopt(sock, opt)
       elsif respond_to?(:accf_arg)
         name = opt[:accept_filter]
         name = DEFAULTS[:accept_filter] if name.nil?
+        sock.listen(opt[:backlog])
+        got = (sock.getsockopt(:SOL_SOCKET, :SO_ACCEPTFILTER) rescue nil).to_s
+        arg = accf_arg(name)
         begin
-          sock.setsockopt(:SOL_SOCKET, :SO_ACCEPTFILTER, accf_arg(name))
+          sock.setsockopt(:SOL_SOCKET, :SO_ACCEPTFILTER, arg)
         rescue => e
           logger.error("#{sock_name(sock)} " \
                        "failed to set accept_filter=#{name} (#{e.inspect})")
-        end
+        end if arg != got
       end
     end
 
-- 
EW