95 lines
2.5 KiB
Go
95 lines
2.5 KiB
Go
// Copyright 2020 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 vfs2
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import (
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"gvisor.dev/gvisor/pkg/abi/linux"
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"gvisor.dev/gvisor/pkg/fspath"
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"gvisor.dev/gvisor/pkg/sentry/kernel"
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"gvisor.dev/gvisor/pkg/sentry/vfs"
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"gvisor.dev/gvisor/pkg/syserror"
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"gvisor.dev/gvisor/pkg/usermem"
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)
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func copyInPath(t *kernel.Task, addr usermem.Addr) (fspath.Path, error) {
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pathname, err := t.CopyInString(addr, linux.PATH_MAX)
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if err != nil {
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return fspath.Path{}, err
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}
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return fspath.Parse(pathname), nil
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}
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type taskPathOperation struct {
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pop vfs.PathOperation
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haveStartRef bool
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}
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func getTaskPathOperation(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPath shouldAllowEmptyPath, shouldFollowFinalSymlink shouldFollowFinalSymlink) (taskPathOperation, error) {
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root := t.FSContext().RootDirectoryVFS2()
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start := root
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haveStartRef := false
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if !path.Absolute {
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if !path.HasComponents() && !bool(shouldAllowEmptyPath) {
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root.DecRef()
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return taskPathOperation{}, syserror.ENOENT
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}
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if dirfd == linux.AT_FDCWD {
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start = t.FSContext().WorkingDirectoryVFS2()
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haveStartRef = true
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} else {
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dirfile := t.GetFileVFS2(dirfd)
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if dirfile == nil {
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root.DecRef()
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return taskPathOperation{}, syserror.EBADF
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}
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start = dirfile.VirtualDentry()
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start.IncRef()
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haveStartRef = true
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dirfile.DecRef()
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}
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}
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return taskPathOperation{
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pop: vfs.PathOperation{
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Root: root,
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Start: start,
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Path: path,
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FollowFinalSymlink: bool(shouldFollowFinalSymlink),
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},
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haveStartRef: haveStartRef,
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}, nil
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}
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func (tpop *taskPathOperation) Release() {
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tpop.pop.Root.DecRef()
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if tpop.haveStartRef {
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tpop.pop.Start.DecRef()
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tpop.haveStartRef = false
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}
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}
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type shouldAllowEmptyPath bool
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const (
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disallowEmptyPath shouldAllowEmptyPath = false
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allowEmptyPath shouldAllowEmptyPath = true
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)
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type shouldFollowFinalSymlink bool
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const (
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nofollowFinalSymlink shouldFollowFinalSymlink = false
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followFinalSymlink shouldFollowFinalSymlink = true
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)
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