From 1dd3a5cac42fe9fea3de05b9bcc2857b5e283774 Mon Sep 17 00:00:00 2001
From: Greg V <greg@unrelenting.technology>
Date: Sun, 30 Sep 2018 15:56:50 +0300
Subject: [PATCH] Allow creating sockets from raw file descriptors

This is useful for socket activation, sandboxes, etc.
---
 src/socket.cr             | 2 +-
 src/socket/tcp_server.cr  | 5 +++++
 src/socket/tcp_socket.cr  | 5 +++++
 src/socket/unix_server.cr | 5 +++++
 src/socket/unix_socket.cr | 3 ++-
 5 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/socket.cr b/src/socket.cr
index 34e28e3b822b..9f3e7bfe0c4e 100644
--- a/src/socket.cr
+++ b/src/socket.cr
@@ -79,7 +79,7 @@ class Socket < IO
     end
   end
 
-  protected def initialize(@fd : Int32, @family, @type, @protocol = Protocol::IP, blocking = false)
+  def initialize(@fd : Int32, @family, @type, @protocol = Protocol::IP, blocking = false)
     @closed = false
     init_close_on_exec(@fd)
 
diff --git a/src/socket/tcp_server.cr b/src/socket/tcp_server.cr
index badb99b0f1cc..6809b833a6ba 100644
--- a/src/socket/tcp_server.cr
+++ b/src/socket/tcp_server.cr
@@ -48,6 +48,11 @@ class TCPServer < TCPSocket
     end
   end
 
+  # Creates a TCPServer from an already configured raw file descriptor
+  def initialize(*, fd : Int32, family : Family = Family::INET)
+    super(fd, family)
+  end
+
   # Creates a new TCP server, listening on all local interfaces (`::`).
   def self.new(port : Int, backlog = SOMAXCONN, reuse_port = false)
     new("::", port, backlog, reuse_port: reuse_port)
diff --git a/src/socket/tcp_socket.cr b/src/socket/tcp_socket.cr
index 56b080ccb360..7a5bdbcd2d0f 100644
--- a/src/socket/tcp_socket.cr
+++ b/src/socket/tcp_socket.cr
@@ -42,6 +42,11 @@ class TCPSocket < IPSocket
     super fd, family, type, protocol
   end
 
+  # Creates a TCPSocket from an already configured raw file descriptor
+  def initialize(*, fd : Int32, family : Family = Family::INET)
+    super fd, family, Type::STREAM, Protocol::TCP
+  end
+
   # Opens a TCP socket to a remote TCP server, yields it to the block, then
   # eventually closes the socket when the block returns.
   #
diff --git a/src/socket/unix_server.cr b/src/socket/unix_server.cr
index 1562674129d6..50c760d986e4 100644
--- a/src/socket/unix_server.cr
+++ b/src/socket/unix_server.cr
@@ -45,6 +45,11 @@ class UNIXServer < UNIXSocket
     end
   end
 
+  # Creates a UNIXServer from an already configured raw file descriptor
+  def initialize(*, fd : Int32, type : Type = Type::STREAM, @path : String? = nil)
+    super(fd, type, path)
+  end
+
   # Creates a new UNIX server and yields it to the block. Eventually closes the
   # server socket when the block returns.
   #
diff --git a/src/socket/unix_socket.cr b/src/socket/unix_socket.cr
index 9956306a929b..bd676831dc21 100644
--- a/src/socket/unix_socket.cr
+++ b/src/socket/unix_socket.cr
@@ -28,7 +28,8 @@ class UNIXSocket < Socket
     super family, type, Protocol::IP
   end
 
-  protected def initialize(fd : Int32, type : Type, @path : String? = nil)
+  # Creates a UNIXSocket from an already configured raw file descriptor
+  def initialize(*, fd : Int32, type : Type = Type::STREAM, @path : String? = nil)
     super fd, Family::UNIX, type, Protocol::IP
   end