[PATCH 1/5] pipe: avoid loading sleepy_penguin

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

The values of F_{GET,SET}PIPE_SZ are architecture-independent
and stable in Linux (unlike Ruby :P), so we won't need to bother
loading an extra .so here for two constants.
---
 lib/dtas/pipe.rb            | 20 ++++++++++++--------
 test/test_sink_pipe_size.rb | 27 ++++++++++++---------------
 2 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/lib/dtas/pipe.rb b/lib/dtas/pipe.rb
index 58d926c..4c3203d 100644
--- a/lib/dtas/pipe.rb
+++ b/lib/dtas/pipe.rb
@@ -1,10 +1,6 @@
 # Copyright (C) 2013-2019 all contributors <dtas-all@nongnu.org>
 # License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
 # frozen_string_literal: true
-begin
-  require 'sleepy_penguin'
-rescue LoadError
-end
 require_relative '../dtas'
 require_relative 'writable_iter'
 require_relative 'nonblock'
@@ -14,6 +10,11 @@ class DTAS::Pipe < DTAS::Nonblock # :nodoc:
   include DTAS::WritableIter
   attr_accessor :sink
 
+  if RUBY_PLATFORM =~ /linux/i && File.readable?('/proc/sys/fs/pipe-max-size')
+    F_SETPIPE_SZ = 1031
+    F_GETPIPE_SZ = 1032
+  end
+
   def self.new
     _, w = rv = pipe
     w.writable_iter_init
@@ -21,13 +22,16 @@ def self.new
   end
 
   def pipe_size=(nr)
-    defined?(SleepyPenguin::F_SETPIPE_SZ) and
-      fcntl(SleepyPenguin::F_SETPIPE_SZ, nr)
+    fcntl(F_SETPIPE_SZ, nr) if defined?(F_SETPIPE_SZ)
+  rescue Errno::EINVAL # old kernel
+  rescue Errno::EPERM
+    # resizes fail if Linux is close to the pipe limit for the user
+    # or if the user does not have permissions to resize
   end
 
   def pipe_size
-    fcntl(SleepyPenguin::F_GETPIPE_SZ)
-  end if defined?(SleepyPenguin::F_GETPIPE_SZ)
+    fcntl(F_GETPIPE_SZ)
+  end if defined?(F_GETPIPE_SZ)
 
   # avoid syscall, we never change IO#nonblock= directly
   def nonblock?
diff --git a/test/test_sink_pipe_size.rb b/test/test_sink_pipe_size.rb
index 1b6db72..bbe2884 100644
--- a/test/test_sink_pipe_size.rb
+++ b/test/test_sink_pipe_size.rb
@@ -1,20 +1,17 @@
 # Copyright (C) 2013-2019 all contributors <dtas-all@nongnu.org>
 # License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
 # frozen_string_literal: true
-begin
-  require 'sleepy_penguin'
-  require './test/player_integration'
-  class TestSinkPipeSizeIntegration < Testcase
-    include PlayerIntegration
+require './test/player_integration'
+class TestSinkPipeSizeIntegration < Testcase
+  include PlayerIntegration
 
-    def test_sink_pipe_size_integration
-      s = client_socket
-      default_sink_pid(s)
-      s.req_ok("sink ed default pipe_size=0x1000")
-      s.req_ok("sink ed default pipe_size=0x10000")
-      s.req_ok("sink ed default pipe_size=")
-      s.req_ok("sink ed default pipe_size=4096")
-    end if SleepyPenguin.const_defined?(:F_SETPIPE_SZ)
+  def test_sink_pipe_size_integration
+    s = client_socket
+    default_sink_pid(s)
+    s.req_ok("sink ed default pipe_size=0x1000")
+    s.req_ok("sink ed default pipe_size=0x10000")
+    s.req_ok("sink ed default pipe_size=")
+    s.req_ok("sink ed default pipe_size=4096")
   end
-rescue LoadError
-end
+end if RUBY_PLATFORM =~ /linux/i &&
+      File.readable?('/proc/sys/fs/pipe-max-size')