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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package root is used for tests that requires sysadmin privileges run.
package root
import (
"fmt"
"io/ioutil"
"os/exec"
"path/filepath"
"strconv"
"strings"
"testing"
"gvisor.dev/gvisor/runsc/dockerutil"
)
// TestChroot verifies that the sandbox is chroot'd and that mounts are cleaned
// up after the sandbox is destroyed.
func TestChroot(t *testing.T) {
d := dockerutil.MakeDocker("chroot-test")
if err := d.Run("alpine", "sleep", "10000"); err != nil {
t.Fatalf("docker run failed: %v", err)
}
defer d.CleanUp()
pid, err := d.SandboxPid()
if err != nil {
t.Fatalf("Docker.SandboxPid(): %v", err)
}
// Check that sandbox is chroot'ed.
procRoot := filepath.Join("/proc", strconv.Itoa(pid), "root")
chroot, err := filepath.EvalSymlinks(procRoot)
if err != nil {
t.Fatalf("error resolving /proc/<pid>/root symlink: %v", err)
}
if chroot != "/" {
t.Errorf("sandbox is not chroot'd, it should be inside: /, got: %q", chroot)
}
path, err := filepath.EvalSymlinks(filepath.Join("/proc", strconv.Itoa(pid), "cwd"))
if err != nil {
t.Fatalf("error resolving /proc/<pid>/cwd symlink: %v", err)
}
if chroot != path {
t.Errorf("sandbox current dir is wrong, want: %q, got: %q", chroot, path)
}
fi, err := ioutil.ReadDir(procRoot)
if err != nil {
t.Fatalf("error listing %q: %v", chroot, err)
}
if want, got := 1, len(fi); want != got {
t.Fatalf("chroot dir got %d entries, want %d", got, want)
}
// chroot dir is prepared by runsc and should contains only /proc.
if fi[0].Name() != "proc" {
t.Errorf("chroot got children %v, want %v", fi[0].Name(), "proc")
}
d.CleanUp()
}
func TestChrootGofer(t *testing.T) {
d := dockerutil.MakeDocker("chroot-test")
if err := d.Run("alpine", "sleep", "10000"); err != nil {
t.Fatalf("docker run failed: %v", err)
}
defer d.CleanUp()
// It's tricky to find gofers. Get sandbox PID first, then find parent. From
// parent get all immediate children, remove the sandbox, and everything else
// are gofers.
sandPID, err := d.SandboxPid()
if err != nil {
t.Fatalf("Docker.SandboxPid(): %v", err)
}
// Find sandbox's parent PID.
cmd := fmt.Sprintf("grep PPid /proc/%d/status | awk '{print $2}'", sandPID)
parent, err := exec.Command("sh", "-c", cmd).CombinedOutput()
if err != nil {
t.Fatalf("failed to fetch runsc (%d) parent PID: %v, out:\n%s", sandPID, err, string(parent))
}
parentPID, err := strconv.Atoi(strings.TrimSpace(string(parent)))
if err != nil {
t.Fatalf("failed to parse PPID %q: %v", string(parent), err)
}
// Get all children from parent.
childrenOut, err := exec.Command("/usr/bin/pgrep", "-P", strconv.Itoa(parentPID)).CombinedOutput()
if err != nil {
t.Fatalf("failed to fetch containerd-shim children: %v", err)
}
children := strings.Split(strings.TrimSpace(string(childrenOut)), "\n")
// This where the root directory is mapped on the host and that's where the
// gofer must have chroot'd to.
root := "/root"
for _, child := range children {
childPID, err := strconv.Atoi(child)
if err != nil {
t.Fatalf("failed to parse child PID %q: %v", child, err)
}
if childPID == sandPID {
// Skip the sandbox, all other immediate children are gofers.
continue
}
// Check that gofer is chroot'ed.
chroot, err := filepath.EvalSymlinks(filepath.Join("/proc", child, "root"))
if err != nil {
t.Fatalf("error resolving /proc/<pid>/root symlink: %v", err)
}
if root != chroot {
t.Errorf("gofer chroot is wrong, want: %q, got: %q", root, chroot)
}
path, err := filepath.EvalSymlinks(filepath.Join("/proc", child, "cwd"))
if err != nil {
t.Fatalf("error resolving /proc/<pid>/cwd symlink: %v", err)
}
if root != path {
t.Errorf("gofer current dir is wrong, want: %q, got: %q", root, path)
}
}
}
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