[PATCH] Check for Socket::TCP_INFO constant before trying to get TCP_INFO

[PATCH] Check for Socket::TCP_INFO constant before trying to get TCP_INFO

[Dylan Thacker-Smith]

The ruby constant Socket::TCP_INFO is only defined if TCP_INFO is defined
in C, so we can just check for the presence of that ruby constant instead
of rescuing SocketError from the call to getsockopt.
---
 lib/unicorn/http_request.rb | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb
index 6dc0aa7..8f1638a 100644
--- a/lib/unicorn/http_request.rb
+++ b/lib/unicorn/http_request.rb
@@ -29,7 +29,7 @@ class Unicorn::HttpParser
   EMPTY_ARRAY = [].freeze
   @@input_class = Unicorn::TeeInput
   @@check_client_connection = false
-  @@tcpi_inspect_ok = nil
+  @@tcpi_inspect_ok = Socket.const_defined?(:TCP_INFO)
 
   def self.input_class
     @@input_class
@@ -154,20 +154,10 @@ def closed_state?(state) # :nodoc:
     # Not that efficient, but probably still better than doing unnecessary
     # work after a client gives up.
     def check_client_connection(socket) # :nodoc:
-      if Unicorn::TCPClient === socket && @@tcpi_inspect_ok != false
-        if @@tcpi_inspect_ok
-          opt = socket.getsockopt(:IPPROTO_TCP, :TCP_INFO).inspect
-        else
-          @@tcpi_inspect_ok = true
-          opt = begin
-            socket.getsockopt(:IPPROTO_TCP, :TCP_INFO)
-          rescue SocketError
-            @@tcpi_inspect_ok = false
-            return write_http_header(socket)
-          end.inspect
-        end
-
+      if Unicorn::TCPClient === socket && @@tcpi_inspect_ok
+        opt = socket.getsockopt(Socket::IPPROTO_TCP, Socket::TCP_INFO).inspect
         if opt =~ /\bstate=(\S+)/
+          @@tcpi_inspect_ok = true
           raise Errno::EPIPE, "client closed connection".freeze,
                 EMPTY_ARRAY if closed_state_str?($1)
         else
-- 
2.10.0

Re: [PATCH] Check for Socket::TCP_INFO constant before trying to get TCP_INFO

[Eric Wong]

Dylan Thacker-Smith <dylan.smith@shopify.com> wrote:
> The ruby constant Socket::TCP_INFO is only defined if TCP_INFO is defined
> in C, so we can just check for the presence of that ruby constant instead
> of rescuing SocketError from the call to getsockopt.

Good catch!  I forget there's systems without TCP_INFO at all :x

> +++ b/lib/unicorn/http_request.rb
> @@ -29,7 +29,7 @@ class Unicorn::HttpParser
>    EMPTY_ARRAY = [].freeze
>    @@input_class = Unicorn::TeeInput
>    @@check_client_connection = false
> -  @@tcpi_inspect_ok = nil
> +  @@tcpi_inspect_ok = Socket.const_defined?(:TCP_INFO)
>  
>    def self.input_class
>      @@input_class
> @@ -154,20 +154,10 @@ def closed_state?(state) # :nodoc:
>      # Not that efficient, but probably still better than doing unnecessary
>      # work after a client gives up.
>      def check_client_connection(socket) # :nodoc:
> -      if Unicorn::TCPClient === socket && @@tcpi_inspect_ok != false
> -        if @@tcpi_inspect_ok
> -          opt = socket.getsockopt(:IPPROTO_TCP, :TCP_INFO).inspect
> -        else
> -          @@tcpi_inspect_ok = true
> -          opt = begin
> -            socket.getsockopt(:IPPROTO_TCP, :TCP_INFO)
> -          rescue SocketError
> -            @@tcpi_inspect_ok = false
> -            return write_http_header(socket)
> -          end.inspect
> -        end
> -
> +      if Unicorn::TCPClient === socket && @@tcpi_inspect_ok
> +        opt = socket.getsockopt(Socket::IPPROTO_TCP, Socket::TCP_INFO).inspect
>          if opt =~ /\bstate=(\S+)/
> +          @@tcpi_inspect_ok = true

Is the last line to set "@@tcpi_inspect_ok = true" still
necessary?  It was necessary in Jeremy's version, but I think
you can safely omit it, now.

>            raise Errno::EPIPE, "client closed connection".freeze,
>                  EMPTY_ARRAY if closed_state_str?($1)
>          else

Anyways, I'm inclined to apply your patch with the redundant
assignment removed (no need to resend).  Thanks.

Re: [PATCH] Check for Socket::TCP_INFO constant before trying to get TCP_INFO

[Dylan Thacker-Smith]

On Sat, Mar 25, 2017 at 10:41 PM, Eric Wong <e@80x24.org> wrote:
> Is the last line to set "@@tcpi_inspect_ok = true" still
> necessary?  It was necessary in Jeremy's version, but I think
> you can safely omit it, now.

No it isn't needed, so you can remove it.

I had just started my patch before seeing his, so reverted his as part
of rebasing and this line was present before his patch.

Re: [PATCH] Check for Socket::TCP_INFO constant before trying to get TCP_INFO

[Eric Wong]

Dylan Thacker-Smith <dylan.smith@shopify.com> wrote:
> On Sat, Mar 25, 2017 at 10:41 PM, Eric Wong <e@80x24.org> wrote:
> > Is the last line to set "@@tcpi_inspect_ok = true" still
> > necessary?  It was necessary in Jeremy's version, but I think
> > you can safely omit it, now.
> 
> No it isn't needed, so you can remove it.
> 
> I had just started my patch before seeing his, so reverted his as part
> of rebasing and this line was present before his patch.

Thanks, pushed as 477a2207869ff6b11a1cdee428b55604f2caa69e
to "master" of git://bogomips.org/unicorn