[Truffle] Add Process.setsid

Author: bjfish

truffle/src/main/java/org/jruby/truffle/nodes/rubinius/PosixNodes.java

@@ -435,6 +435,20 @@ public int setuid(int uid) {
 
     }
 
+    @CoreMethod(names = "setsid", isModuleFunction = true)
+    public abstract static class SetSidNode extends CoreMethodArrayArgumentsNode {
+
+        public SetSidNode(RubyContext context, SourceSection sourceSection) {
+            super(context, sourceSection);
+        }
+
+        @Specialization
+        public int setsid() {
+            return posix().setsid();
+        }
+
+    }
+
     @CoreMethod(names = "flock", isModuleFunction = true, required = 2, lowerFixnumParameters = {0, 1})
     public abstract static class FlockNode extends CoreMethodArrayArgumentsNode {
 

truffle/src/main/ruby/core/rubinius/common/process.rb

@@ -64,6 +64,12 @@ module Constants
 
   FFI = Rubinius::FFI
 
+  def self.setsid
+    pgid = FFI::Platform::POSIX.setsid
+    Errno.handle if pgid == -1
+    pgid
+  end
+
   def self.times
     Struct::Tms.new(*cpu_times)
   end