66 lines
2.0 KiB
Go
66 lines
2.0 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package proc
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import (
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"bytes"
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"fmt"
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"gvisor.dev/gvisor/pkg/context"
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"gvisor.dev/gvisor/pkg/sentry/fs"
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"gvisor.dev/gvisor/pkg/sentry/fs/proc/seqfile"
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)
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// LINT.IfChange
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// filesystemsData backs /proc/filesystems.
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//
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// +stateify savable
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type filesystemsData struct{}
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// NeedsUpdate returns true on the first generation. The set of registered file
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// systems doesn't change so there's no need to generate SeqData more than once.
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func (*filesystemsData) NeedsUpdate(generation int64) bool {
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return generation == 0
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}
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// ReadSeqFileData returns data for the SeqFile reader.
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// SeqData, the current generation and where in the file the handle corresponds to.
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func (*filesystemsData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
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// We don't ever expect to see a non-nil SeqHandle.
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if h != nil {
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return nil, 0
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}
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// Generate the file contents.
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var buf bytes.Buffer
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for _, sys := range fs.GetFilesystems() {
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if !sys.AllowUserList() {
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continue
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}
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nodev := "nodev"
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if sys.Flags()&fs.FilesystemRequiresDev != 0 {
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nodev = ""
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}
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// Matches the format of fs/filesystems.c:filesystems_proc_show.
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fmt.Fprintf(&buf, "%s\t%s\n", nodev, sys.Name())
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}
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// Return the SeqData and advance the generation counter.
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return []seqfile.SeqData{{Buf: buf.Bytes(), Handle: (*filesystemsData)(nil)}}, 1
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}
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// LINT.ThenChange(../../fsimpl/proc/filesystem.go)
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