os.Setenv("GODEBUG", godebug)

	if os.Getenv("GO_EXEC_TEST_PID") != "" {
		return
	}
	if runtime.GOOS == "windows" {
		return
	}
	for fd := uintptr(3); fd <= 100; fd++ {
		if poll.IsPollDescriptor(fd) {
			continue
		}

		if fdtest.Exists(fd) {
			haveUnexpectedFDs = true
			return
		}
	}
}

// TestMain allows the test binary to impersonate many other binaries,

			fdMu.Lock()
			defer fdMu.Unlock()
			if len(fds) == 0 {
				return nil
			}
			fdsCopy := fds
			for _, fd := range fdsCopy {
				// Grab a fallback disk
				fds = fds[1:]
				if fd != nil && fd.IsOnline() {
					return fd
				}
			}
		}
		// Either no more disks for fallback or
		// not a storage error.
		return nil
	}

		_, err := io.Copy(w, pr)
		pr.Close() // in case io.Copy stopped due to write error
		return err
	})
	return pw, nil
}

func closeDescriptors(closers []io.Closer) {
	for _, fd := range closers {
		fd.Close()
	}
}

// Run starts the specified command and waits for it to complete.
//
// The returned error is nil if the command runs, has no problems