gvisor/pkg/sentry/fs/sys/devices.go

92 lines
2.7 KiB
Go

// 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 sys
import (
"fmt"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
"gvisor.dev/gvisor/pkg/sentry/kernel"
)
// +stateify savable
type cpunum struct {
fsutil.InodeGenericChecker `state:"nosave"`
fsutil.InodeNoExtendedAttributes `state:"nosave"`
fsutil.InodeNoopRelease `state:"nosave"`
fsutil.InodeNoopWriteOut `state:"nosave"`
fsutil.InodeNotAllocatable `state:"nosave"`
fsutil.InodeNotDirectory `state:"nosave"`
fsutil.InodeNotMappable `state:"nosave"`
fsutil.InodeNotSocket `state:"nosave"`
fsutil.InodeNotSymlink `state:"nosave"`
fsutil.InodeNotTruncatable `state:"nosave"`
fsutil.InodeNotVirtual `state:"nosave"`
fsutil.InodeSimpleAttributes
fsutil.InodeStaticFileGetter
}
var _ fs.InodeOperations = (*cpunum)(nil)
func newPossible(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
var maxCore uint
k := kernel.KernelFromContext(ctx)
if k != nil {
maxCore = k.ApplicationCores() - 1
}
contents := []byte(fmt.Sprintf("0-%d\n", maxCore))
c := &cpunum{
InodeSimpleAttributes: fsutil.NewInodeSimpleAttributes(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), linux.SYSFS_MAGIC),
InodeStaticFileGetter: fsutil.InodeStaticFileGetter{
Contents: contents,
},
}
return newFile(ctx, c, msrc)
}
func newCPU(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
m := map[string]*fs.Inode{
"online": newPossible(ctx, msrc),
"possible": newPossible(ctx, msrc),
"present": newPossible(ctx, msrc),
}
// Add directories for each of the cpus.
if k := kernel.KernelFromContext(ctx); k != nil {
for i := 0; uint(i) < k.ApplicationCores(); i++ {
m[fmt.Sprintf("cpu%d", i)] = newDir(ctx, msrc, nil)
}
}
return newDir(ctx, msrc, m)
}
func newSystemDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
return newDir(ctx, msrc, map[string]*fs.Inode{
"cpu": newCPU(ctx, msrc),
})
}
func newDevicesDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
return newDir(ctx, msrc, map[string]*fs.Inode{
"system": newSystemDir(ctx, msrc),
})
}