Fix file descriptor leaks and add test

* Add response.Body.Close() where needed to release HTTP
  connections to API server.
* Add tests to ensure no general leaks occur. 100% coverage would be
  required to ensure no leaks on any call.
* Update code comments to be godoc correct

Signed-off-by: Jhon Honce <jhonce@redhat.com>

3 files changed, 134 insertions, 8 deletions

diff --git a/pkg/bindings/test/attach_test.go b/pkg/bindings/test/attach_test.go
index fbdf18d44..5c3ec48e4 100644
--- a/pkg/bindings/test/attach_test.go
+++ b/pkg/bindings/test/attach_test.go
@@ -81,10 +81,9 @@ var _ = Describe("Podman containers attach", func() {
 		tickTock := time.NewTimer(2 * time.Second)
 		go func() {
 			<-tickTock.C
-			timeout := uint(5)
-			err := containers.Stop(bt.conn, ctnr.ID, new(containers.StopOptions).WithTimeout(timeout))
+			err := containers.Stop(bt.conn, ctnr.ID, new(containers.StopOptions).WithTimeout(uint(5)))
 			if err != nil {
-				GinkgoWriter.Write([]byte(err.Error()))
+				fmt.Fprint(GinkgoWriter, err.Error())
 			}
 		}()
 
diff --git a/pkg/bindings/test/common_test.go b/pkg/bindings/test/common_test.go
index 9bac4b620..91ebe21fc 100644
--- a/pkg/bindings/test/common_test.go
+++ b/pkg/bindings/test/common_test.go
@@ -8,6 +8,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/containers/podman/v3/libpod/define"
 	. "github.com/containers/podman/v3/pkg/bindings"
@@ -150,11 +151,21 @@ func createTempDirInTempDir() (string, error) {
 }
 
 func (b *bindingTest) startAPIService() *gexec.Session {
-	var (
-		cmd []string
-	)
-	cmd = append(cmd, "--log-level=debug", "--events-backend=file", "system", "service", "--timeout=0", b.sock)
-	return b.runPodman(cmd)
+	cmd := []string{"--log-level=debug", "--events-backend=file", "system", "service", "--timeout=0", b.sock}
+	session := b.runPodman(cmd)
+
+	sock := strings.TrimPrefix(b.sock, "unix://")
+	for i := 0; i < 10; i++ {
+		if _, err := os.Stat(sock); err != nil {
+			if !os.IsNotExist(err) {
+				break
+			}
+			time.Sleep(time.Second)
+			continue
+		}
+		break
+	}
+	return session
 }
 
 func (b *bindingTest) cleanup() {
diff --git a/pkg/bindings/test/resource_test.go b/pkg/bindings/test/resource_test.go
new file mode 100644
index 000000000..b12d1ccd6
--- /dev/null
+++ b/pkg/bindings/test/resource_test.go
@@ -0,0 +1,116 @@
+package test_bindings
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"reflect"
+	"strconv"
+	"syscall"
+
+	"github.com/containers/podman/v3/pkg/bindings"
+	"github.com/containers/podman/v3/pkg/bindings/containers"
+	"github.com/containers/podman/v3/pkg/bindings/images"
+	"github.com/containers/podman/v3/pkg/bindings/pods"
+	"github.com/containers/podman/v3/pkg/bindings/system"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	. "github.com/onsi/gomega/gexec"
+)
+
+var _ = Describe("Verify Podman resources", func() {
+	var (
+		bt *bindingTest
+		s  *Session
+	)
+
+	BeforeEach(func() {
+		bt = newBindingTest()
+		s = bt.startAPIService()
+		err := bt.NewConnection()
+		Expect(err).ShouldNot(HaveOccurred())
+	})
+
+	AfterEach(func() {
+		s.Kill()
+		bt.cleanup()
+	})
+
+	It("no leaked connections", func() {
+		conn, err := bindings.NewConnection(context.Background(), bt.sock)
+		Expect(err).ShouldNot(HaveOccurred())
+
+		// Record details on open file descriptors before using API
+		buffer := lsof()
+
+		// Record open fd from /proc
+		start, err := readProc()
+		Expect(err).ShouldNot(HaveOccurred())
+
+		// Run some operations
+		_, err = system.Info(conn, nil)
+		Expect(err).ShouldNot(HaveOccurred())
+		_, err = images.List(conn, nil)
+		Expect(err).ShouldNot(HaveOccurred())
+		_, err = containers.List(conn, nil)
+		Expect(err).ShouldNot(HaveOccurred())
+		_, err = pods.List(conn, nil)
+		Expect(err).ShouldNot(HaveOccurred())
+
+		podman, _ := bindings.GetClient(conn)
+		podman.Client.CloseIdleConnections()
+
+		// Record open fd from /proc
+		finished, err := readProc()
+		Expect(err).ShouldNot(HaveOccurred())
+		if !reflect.DeepEqual(finished, start) {
+			fmt.Fprintf(GinkgoWriter, "Open FDs:\nlsof Before:\n%s\n", buffer)
+
+			// Record details on open file descriptors after using API
+			buffer := lsof()
+			fmt.Fprintf(GinkgoWriter, "lsof After:\n%s\n", buffer)
+
+			// We know test has failed. Easier to let ginkgo format output.
+			Expect(finished).Should(Equal(start))
+		}
+	})
+})
+
+func lsof() string {
+	lsof := exec.Command("lsof", "+E", "-p", strconv.Itoa(os.Getpid()))
+	buffer, err := lsof.Output()
+	Expect(err).ShouldNot(HaveOccurred())
+	return string(buffer)
+}
+
+func readProc() ([]string, error) {
+	syscall.Sync()
+
+	names := make([]string, 0)
+	err := filepath.WalkDir(fmt.Sprintf("/proc/%d/fd", os.Getpid()),
+		func(path string, d fs.DirEntry, err error) error {
+			name := path + " -> "
+
+			switch {
+			case d.IsDir():
+				return nil
+			case err != nil:
+				name += err.Error()
+			case d.Type()&fs.ModeSymlink != 0:
+				n, err := os.Readlink(path)
+				if err != nil && !os.IsNotExist(err) {
+					return err
+				}
+				if n == "" {
+					n = d.Type().String()
+				}
+				name += n
+			}
+			names = append(names, name)
+			return nil
+		})
+	return names, err
+}