runner.rb in r10k-1.4.0

- old
+ new

@@ -37,12 +37,18 @@
     if @pid
       _, @status = Process.waitpid2(@pid)
     end
 
     stdout = @stdout_r.read
-    stderr = @stderr_r.read
+    # Use non-blocking read for stderr_r to work around an issue with OpenSSH
+    # ControlPersist: https://bugzilla.mindrot.org/show_bug.cgi?id=1988
+    # Blocking should not occur in any other case since the process that was
+    # attached to the pipe has already terminated.
+    stderr = read_nonblock(@stderr_r)
 
+    @stdout_r.close
+    @stderr_r.close
     @result = R10K::Util::Subprocess::Result.new(@argv, stdout, stderr, @status.exitstatus)
   end
 
   def run
     start
@@ -86,10 +92,11 @@
 
     if not exec_r.eof?
       msg = exec_r.read || "exec() failed"
       raise "Could not execute #{@argv.join(' ')}: #{msg}"
     end
+    exec_r.close
   end
 
   # Create a pipe so that the parent can verify that the child process
   # successfully executed. The pipe will be closed on a successful exec(),
   # and will contain an error message on failure.
@@ -105,9 +112,29 @@
 
   def attach_pipes
     @stdout_r, @stdout_w = ::IO.pipe
     @stderr_r, @stderr_w = ::IO.pipe
 
+    @stdout_r.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
+    @stdout_w.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
+    @stderr_r.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
+    @stderr_w.fcntl(Fcntl::F_SETFD, Fcntl::FD_CLOEXEC)
+
     @io.stdout = @stdout_w
     @io.stderr = @stderr_w
+  end
+
+  # Perform non-blocking reads on a pipe that could still be open
+  # Give up on reaching EOF or blocking and return what was read
+  def read_nonblock(rd_io)
+    data = ''
+    begin
+      # Loop until EOF or blocking
+      loop do
+          # do an 8k non-blocking read and append the result
+          data << rd_io.read_nonblock(8192)
+      end
+    rescue EOFError, Errno::EAGAIN, Errno::EWOULDBLOCK
+    end
+    data
   end
 end