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// Copyright 2018 Google LLC
//
// 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 proc
import (
"fmt"
"io"
"strconv"
"gvisor.googlesource.com/gvisor/pkg/abi/linux"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/fsutil"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/proc/seqfile"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs"
"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
"gvisor.googlesource.com/gvisor/pkg/sentry/socket/rpcinet"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
"gvisor.googlesource.com/gvisor/pkg/waiter"
)
// mmapMinAddrData backs /proc/sys/vm/mmap_min_addr.
//
// +stateify savable
type mmapMinAddrData struct {
k *kernel.Kernel
}
// NeedsUpdate implements seqfile.SeqSource.NeedsUpdate.
func (*mmapMinAddrData) NeedsUpdate(generation int64) bool {
return true
}
// ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
func (d *mmapMinAddrData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
if h != nil {
return nil, 0
}
return []seqfile.SeqData{
{
Buf: []byte(fmt.Sprintf("%d\n", d.k.Platform.MinUserAddress())),
Handle: (*mmapMinAddrData)(nil),
},
}, 0
}
// +stateify savable
type overcommitMemory struct{}
func (*overcommitMemory) NeedsUpdate(generation int64) bool {
return true
}
// ReadSeqFileData implements seqfile.SeqSource.
func (*overcommitMemory) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
if h != nil {
return nil, 0
}
return []seqfile.SeqData{
{
Buf: []byte("0\n"),
Handle: (*overcommitMemory)(nil),
},
}, 0
}
func (p *proc) newKernelDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
h := hostname{
SimpleFileInode: *fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), linux.PROC_SUPER_MAGIC),
}
children := map[string]*fs.Inode{
"hostname": newProcInode(&h, msrc, fs.SpecialFile, nil),
"shmall": newStaticProcInode(ctx, msrc, []byte(strconv.FormatUint(linux.SHMALL, 10))),
"shmmax": newStaticProcInode(ctx, msrc, []byte(strconv.FormatUint(linux.SHMMAX, 10))),
"shmmni": newStaticProcInode(ctx, msrc, []byte(strconv.FormatUint(linux.SHMMNI, 10))),
}
d := ramfs.NewDir(ctx, children, fs.RootOwner, fs.FilePermsFromMode(0555))
return newProcInode(d, msrc, fs.SpecialDirectory, nil)
}
func (p *proc) newVMDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
children := map[string]*fs.Inode{
"mmap_min_addr": seqfile.NewSeqFileInode(ctx, &mmapMinAddrData{p.k}, msrc),
"overcommit_memory": seqfile.NewSeqFileInode(ctx, &overcommitMemory{}, msrc),
}
d := ramfs.NewDir(ctx, children, fs.RootOwner, fs.FilePermsFromMode(0555))
return newProcInode(d, msrc, fs.SpecialDirectory, nil)
}
func (p *proc) newSysDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
children := map[string]*fs.Inode{
"kernel": p.newKernelDir(ctx, msrc),
"vm": p.newVMDir(ctx, msrc),
}
// If we're using rpcinet we will let it manage /proc/sys/net.
if _, ok := p.k.NetworkStack().(*rpcinet.Stack); ok {
children["net"] = newRPCInetProcSysNet(ctx, msrc)
} else {
children["net"] = p.newSysNetDir(ctx, msrc)
}
d := ramfs.NewDir(ctx, children, fs.RootOwner, fs.FilePermsFromMode(0555))
return newProcInode(d, msrc, fs.SpecialDirectory, nil)
}
// hostname is the inode for a file containing the system hostname.
//
// +stateify savable
type hostname struct {
fsutil.SimpleFileInode
}
// GetFile implements fs.InodeOperations.GetFile.
func (h *hostname) GetFile(ctx context.Context, d *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
return fs.NewFile(ctx, d, flags, &hostnameFile{}), nil
}
var _ fs.InodeOperations = (*hostname)(nil)
// +stateify savable
type hostnameFile struct {
waiter.AlwaysReady `state:"nosave"`
fsutil.FileNoIoctl `state:"nosave"`
fsutil.FileNoMMap `state:"nosave"`
fsutil.FileNoSeek `state:"nosave"`
fsutil.FileNoopFlush `state:"nosave"`
fsutil.FileNoopFsync `state:"nosave"`
fsutil.FileNoopRelease `state:"nosave"`
fsutil.FileNotDirReaddir `state:"nosave"`
fsutil.FileNoWrite `state:"nosave"`
fsutil.FileUseInodeUnstableAttr `state:"nosave"`
}
// Read implements fs.FileOperations.Read.
func (hf *hostnameFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
utsns := kernel.UTSNamespaceFromContext(ctx)
contents := []byte(utsns.HostName() + "\n")
if offset >= int64(len(contents)) {
return 0, io.EOF
}
n, err := dst.CopyOut(ctx, contents[offset:])
return int64(n), err
}
var _ fs.FileOperations = (*hostnameFile)(nil)
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