Avoid leaking file descriptors after Process.fork

sass-contrib · Dec 4, 2023 · a2c288d · a2c288d
1 parent 2676715
commit a2c288d
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Showing 2 changed files with 23 additions and 15 deletions.
diff --git a/lib/sass/compiler/connection.rb b/lib/sass/compiler/connection.rb
@@ -12,7 +12,7 @@ class Compiler
     class Connection
       def initialize(dispatcher)
         @mutex = Mutex.new
-        @stdin, stdout, stderr, @wait_thread = begin
+        @stdin, @stdout, @stderr, @wait_thread = begin
           Open3.popen3(*CLI::COMMAND, '--embedded', chdir: __dir__)
         rescue Errno::ENOENT
           require_relative '../elf'
@@ -26,27 +26,27 @@ def initialize(dispatcher)
 
         Thread.new do
           Thread.current.name = 'sass-embedded-process-stdout-poller'
-          stdout.binmode
+          @stdout.binmode
           loop do
-            length = Varint.read(stdout)
-            id = Varint.read(stdout)
-            proto = stdout.read(length - Varint.length(id))
+            length = Varint.read(@stdout)
+            id = Varint.read(@stdout)
+            proto = @stdout.read(length - Varint.length(id))
             dispatcher.receive_proto(id, proto)
           rescue IOError, Errno::EBADF, Errno::EPROTO => e
             dispatcher.error(e)
             break
           end
-          stdout.close
+          @stdout.close
         end
 
         Thread.new do
           Thread.current.name = 'sass-embedded-process-stderr-poller'
           loop do
-            warn(stderr.readline, uplevel: 1)
+            warn(@stderr.readline, uplevel: 1)
           rescue IOError, Errno::EBADF
             break
           end
-          stderr.close
+          @stderr.close
         end
       end
 

diff --git a/lib/sass/embedded.rb b/lib/sass/embedded.rb
@@ -95,18 +95,26 @@ def current_time
 
         Process.singleton_class.prepend(Module.new do
           define_method :_fork do
-            compiler.instance_eval do
-              @dispatcher.instance_eval do
-                @mutex.synchronize do
-                  @dispatcher.instance_eval do
-                    @mutex.synchronize do
-                      @id = 0xffffffff
+            pid = super()
+            if pid.zero?
+              compiler.instance_eval do
+                @dispatcher.instance_eval do
+                  @mutex.synchronize do
+                    @dispatcher.instance_eval do
+                      @mutex.synchronize do
+                        @id = 0xffffffff
+                        @connection.instance_eval do
+                          @stdin.close
+                          @stdout.close
+                          @stderr.close
+                        end
+                      end
                     end
                   end
                 end
               end
             end
-            super()
+            pid
           end
         end)