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// Copyright 2020 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 devtmpfs
import (
"testing"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/sentry/contexttest"
"gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
func TestDevtmpfs(t *testing.T) {
ctx := contexttest.Context(t)
creds := auth.CredentialsFromContext(ctx)
vfsObj := &vfs.VirtualFilesystem{}
if err := vfsObj.Init(); err != nil {
t.Fatalf("VFS init: %v", err)
}
// Register tmpfs just so that we can have a root filesystem that isn't
// devtmpfs.
vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
AllowUserMount: true,
})
vfsObj.MustRegisterFilesystemType("devtmpfs", &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
AllowUserMount: true,
})
// Create a test mount namespace with devtmpfs mounted at "/dev".
const devPath = "/dev"
mntns, err := vfsObj.NewMountNamespace(ctx, creds, "tmpfs" /* source */, "tmpfs" /* fsTypeName */, &vfs.GetFilesystemOptions{})
if err != nil {
t.Fatalf("failed to create tmpfs root mount: %v", err)
}
defer mntns.DecRef()
root := mntns.Root()
defer root.DecRef()
devpop := vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(devPath),
}
if err := vfsObj.MkdirAt(ctx, creds, &devpop, &vfs.MkdirOptions{
Mode: 0755,
}); err != nil {
t.Fatalf("failed to create mount point: %v", err)
}
if err := vfsObj.MountAt(ctx, creds, "devtmpfs" /* source */, &devpop, "devtmpfs" /* fsTypeName */, &vfs.MountOptions{}); err != nil {
t.Fatalf("failed to mount devtmpfs: %v", err)
}
a, err := NewAccessor(ctx, vfsObj, creds, "devtmpfs")
if err != nil {
t.Fatalf("failed to create devtmpfs.Accessor: %v", err)
}
defer a.Release()
// Create "userspace-initialized" files using a devtmpfs.Accessor.
if err := a.UserspaceInit(ctx); err != nil {
t.Fatalf("failed to userspace-initialize devtmpfs: %v", err)
}
// Created files should be visible in the test mount namespace.
abspath := devPath + "/fd"
target, err := vfsObj.ReadlinkAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
})
if want := "/proc/self/fd"; err != nil || target != want {
t.Fatalf("readlink(%q): got (%q, %v), wanted (%q, nil)", abspath, target, err, want)
}
// Create a dummy device special file using a devtmpfs.Accessor.
const (
pathInDev = "dummy"
kind = vfs.CharDevice
major = 12
minor = 34
perms = 0600
wantMode = linux.S_IFCHR | perms
)
if err := a.CreateDeviceFile(ctx, pathInDev, kind, major, minor, perms); err != nil {
t.Fatalf("failed to create device file: %v", err)
}
// The device special file should be visible in the test mount namespace.
abspath = devPath + "/" + pathInDev
stat, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{
Root: root,
Start: root,
Path: fspath.Parse(abspath),
}, &vfs.StatOptions{
Mask: linux.STATX_TYPE | linux.STATX_MODE,
})
if err != nil {
t.Fatalf("failed to stat device file at %q: %v", abspath, err)
}
if stat.Mode != wantMode {
t.Errorf("device file mode: got %v, wanted %v", stat.Mode, wantMode)
}
if stat.RdevMajor != major {
t.Errorf("major device number: got %v, wanted %v", stat.RdevMajor, major)
}
if stat.RdevMinor != minor {
t.Errorf("minor device number: got %v, wanted %v", stat.RdevMinor, minor)
}
}
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