inspect: show mounts info from CRI/ctr containers

Fix containerd#2934

Containers created by CRI or ctr with bind mounts
don't have label "nerdct/mounts".

However, 'inspect' with dockercompat mode only parses mounts
from label "nerdct/mounts".

After this patch, 'inspect' with dockercompat mode can
show CRI and ctr container bind mounts.

ResolvConfPath, HostnamePath and Hostname are taken to the same
consideration.

Signed-off-by: baijia <baijia.wr@antgroup.com>

pkg/inspecttypes/dockercompat/dockercompat.go

@@ -32,6 +32,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/containerd/containerd"
@@ -210,6 +211,7 @@ type NetworkEndpointSettings struct {
 
 // ContainerFromNative instantiates a Docker-compatible Container from containerd-native Container.
 func ContainerFromNative(n *native.Container) (*Container, error) {
+	var hostname string
 	c := &Container{
 		ID:       n.ID,
 		Created:  n.CreatedAt.Format(time.RFC3339Nano),
@@ -231,15 +233,25 @@ func ContainerFromNative(n *native.Container) (*Container, error) {
 			}
 			c.AppArmorProfile = p.ApparmorProfile
 		}
+		c.Mounts = mountsFromNative(sp.Mounts)
+		for _, mount := range c.Mounts {
+			if mount.Destination == "/etc/resolv.conf" {
+				c.ResolvConfPath = mount.Source
+			}
+			if mount.Destination == "/etc/hostname" {
+				c.HostnamePath = mount.Source
+			}
+		}
+		hostname = sp.Hostname
 	}
 	if nerdctlStateDir := n.Labels[labels.StateDir]; nerdctlStateDir != "" {
-		c.ResolvConfPath = filepath.Join(nerdctlStateDir, "resolv.conf")
-		if _, err := os.Stat(c.ResolvConfPath); err != nil {
-			c.ResolvConfPath = ""
+		resolvConfPath := filepath.Join(nerdctlStateDir, "resolv.conf")
+		if _, err := os.Stat(resolvConfPath); err == nil {
+			c.ResolvConfPath = resolvConfPath
 		}
-		c.HostnamePath = filepath.Join(nerdctlStateDir, "hostname")
-		if _, err := os.Stat(c.HostnamePath); err != nil {
-			c.HostnamePath = ""
+		hostnamePath := filepath.Join(nerdctlStateDir, "hostname")
+		if _, err := os.Stat(hostnamePath); err == nil {
+			c.HostnamePath = hostnamePath
 		}
 		c.LogPath = filepath.Join(nerdctlStateDir, n.ID+"-json.log")
 		if _, err := os.Stat(c.LogPath); err != nil {
@@ -273,9 +285,12 @@ func ContainerFromNative(n *native.Container) (*Container, error) {
 	}
 	c.State = cs
 	c.Config = &Config{
-		Hostname: n.Labels[labels.Hostname],
-		Labels:   n.Labels,
+		Labels: n.Labels,
 	}
+	if n.Labels[labels.Hostname] != "" {
+		hostname = n.Labels[labels.Hostname]
+	}
+	c.Config.Hostname = hostname
 
 	return c, nil
 }
@@ -323,6 +338,27 @@ func ImageFromNative(n *native.Image) (*Image, error) {
 	i.Size = n.Size
 	return i, nil
 }
+
+// mountsFromNative only filters bind mount to transform from native container.
+// Because native container shows all types of mounts, such as tmpfs, proc, sysfs.
+func mountsFromNative(spMounts []specs.Mount) []MountPoint {
+	var mountpoins []MountPoint
+	for _, m := range spMounts {
+		var mp MountPoint
+		if m.Type != "bind" {
+			continue
+		}
+		mp.Type = m.Type
+		mp.Source = m.Source
+		mp.Destination = m.Destination
+		mp.Mode = strings.Join(m.Options, ",")
+		mp.RW, mp.Propagation = ParseMountProperties(m.Options)
+		mountpoins = append(mountpoins, mp)
+	}
+
+	return mountpoins
+}
+
 func statusFromNative(x containerd.Status, labels map[string]string) string {
 	switch s := x.Status; s {
 	case containerd.Stopped:

pkg/inspecttypes/dockercompat/dockercompat_test.go

@@ -0,0 +1,217 @@
+package dockercompat
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/containers"
+	"github.com/containerd/nerdctl/v2/pkg/inspecttypes/native"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"gotest.tools/v3/assert"
+)
+
+func TestContainerFromNative(t *testing.T) {
+	testcase := []struct {
+		name     string
+		n        *native.Container
+		expected *Container
+	}{
+		// nerdctl container, mount /mnt/foo:/mnt/foo:rw,rslave; ResolvConfPath; hostname
+		{
+			name: "container from nerdctl",
+			n: &native.Container{
+				Container: containers.Container{
+					Labels: map[string]string{
+						"nerdctl/mounts":    "[{\"Type\":\"bind\",\"Source\":\"/mnt/foo\",\"Destination\":\"/mnt/foo\",\"Mode\":\"rshared,rw\",\"RW\":true,\"Propagation\":\"rshared\"}]",
+						"nerdctl/state-dir": "/mock-state-dir",
+						"nerdctl/hostname":  "host1",
+					},
+				},
+				Spec: &specs.Spec{},
+				Process: &native.Process{
+					Pid: 10000,
+					Status: containerd.Status{
+						Status: "running",
+					},
+				},
+			},
+			expected: &Container{
+				Created:        "0001-01-01T00:00:00Z",
+				Platform:       runtime.GOOS,
+				ResolvConfPath: "/mock-state-dir/resolv.conf",
+				State: &ContainerState{
+					Status:     "running",
+					Running:    true,
+					Pid:        10000,
+					FinishedAt: "0001-01-01T00:00:00Z",
+				},
+				Mounts: []MountPoint{
+					{
+						Type:        "bind",
+						Source:      "/mnt/foo",
+						Destination: "/mnt/foo",
+						Mode:        "rshared,rw",
+						RW:          true,
+						Propagation: "rshared",
+					},
+				},
+				Config: &Config{
+					Labels: map[string]string{
+						"nerdctl/mounts":    "[{\"Type\":\"bind\",\"Source\":\"/mnt/foo\",\"Destination\":\"/mnt/foo\",\"Mode\":\"rshared,rw\",\"RW\":true,\"Propagation\":\"rshared\"}]",
+						"nerdctl/state-dir": "/mock-state-dir",
+						"nerdctl/hostname":  "host1",
+					},
+					Hostname: "host1",
+				},
+			},
+		},
+		// cri container, mount /mnt/foo:/mnt/foo:rw,rslave; mount resolv.conf and hostname; internal sysfs mount
+		{
+			name: "container from cri",
+			n: &native.Container{
+				Container: containers.Container{},
+				Spec: &specs.Spec{
+					Mounts: []specs.Mount{
+						{
+							Destination: "/etc/resolv.conf",
+							Type:        "bind",
+							Source:      "/mock-sandbox-dir/resolv.conf",
+							Options:     []string{"rbind", "rprivate", "rw"},
+						},
+						{
+							Destination: "/etc/hostname",
+							Type:        "bind",
+							Source:      "/mock-sandbox-dir/hostname",
+							Options:     []string{"rbind", "rprivate", "rw"},
+						},
+						{
+							Destination: "/mnt/foo",
+							Type:        "bind",
+							Source:      "/mnt/foo",
+							Options:     []string{"rbind", "rslave", "rw"},
+						},
+						{
+							Destination: "/sys",
+							Type:        "sysfs",
+							Source:      "sysfs",
+							Options:     []string{"nosuid", "noexec", "nodev", "ro"},
+						},
+					},
+				},
+				Process: &native.Process{
+					Pid: 10000,
+					Status: containerd.Status{
+						Status: "running",
+					},
+				},
+			},
+			expected: &Container{
+				Created:        "0001-01-01T00:00:00Z",
+				Platform:       runtime.GOOS,
+				ResolvConfPath: "/mock-sandbox-dir/resolv.conf",
+				HostnamePath:   "/mock-sandbox-dir/hostname",
+				State: &ContainerState{
+					Status:     "running",
+					Running:    true,
+					Pid:        10000,
+					FinishedAt: "0001-01-01T00:00:00Z",
+				},
+				Mounts: []MountPoint{
+					{
+						Type:        "bind",
+						Source:      "/mock-sandbox-dir/resolv.conf",
+						Destination: "/etc/resolv.conf",
+						Mode:        "rbind,rprivate,rw",
+						RW:          true,
+						Propagation: "rprivate",
+					},
+					{
+						Type:        "bind",
+						Source:      "/mock-sandbox-dir/hostname",
+						Destination: "/etc/hostname",
+						Mode:        "rbind,rprivate,rw",
+						RW:          true,
+						Propagation: "rprivate",
+					},
+					{
+						Type:        "bind",
+						Source:      "/mnt/foo",
+						Destination: "/mnt/foo",
+						Mode:        "rbind,rslave,rw",
+						RW:          true,
+						Propagation: "rslave",
+					},
+					// ignore sysfs mountpoint
+				},
+				Config: &Config{},
+			},
+		},
+		// ctr container, mount /mnt/foo:/mnt/foo:rw,rslave; internal sysfs mount; hostname
+		{
+			name: "container from ctr",
+			n: &native.Container{
+				Container: containers.Container{},
+				Spec: &specs.Spec{
+					Hostname: "host1",
+					Mounts: []specs.Mount{
+						{
+							Destination: "/mnt/foo",
+							Type:        "bind",
+							Source:      "/mnt/foo",
+							Options:     []string{"rbind", "rslave", "rw"},
+						},
+						{
+							Destination: "/sys",
+							Type:        "sysfs",
+							Source:      "sysfs",
+							Options:     []string{"nosuid", "noexec", "nodev", "ro"},
+						},
+					},
+				},
+				Process: &native.Process{
+					Pid: 10000,
+					Status: containerd.Status{
+						Status: "running",
+					},
+				},
+			},
+			expected: &Container{
+				Created:  "0001-01-01T00:00:00Z",
+				Platform: runtime.GOOS,
+				State: &ContainerState{
+					Status:     "running",
+					Running:    true,
+					Pid:        10000,
+					FinishedAt: "0001-01-01T00:00:00Z",
+				},
+				Mounts: []MountPoint{
+					{
+						Type:        "bind",
+						Source:      "/mnt/foo",
+						Destination: "/mnt/foo",
+						Mode:        "rbind,rslave,rw",
+						RW:          true,
+						Propagation: "rslave",
+					},
+					// ignore sysfs mountpoint
+				},
+				Config: &Config{
+					Hostname: "host1",
+				},
+			},
+		},
+	}
+
+	os.Mkdir("/mock-state-dir", 0755)
+	os.WriteFile(filepath.Join("/mock-state-dir", "resolv.conf"), []byte("hello"), 0600)
+	defer os.RemoveAll("/mock-state-dir")
+
+	for _, tc := range testcase {
+		d, _ := ContainerFromNative(tc.n)
+		assert.DeepEqual(t, d, tc.expected)
+	}
+}