summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/fsimpl/kernfs/fstree.go
blob: 9dc52dabc9caa06cd10bb9e3eb303a34380bab61 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
package kernfs

import (
	"gvisor.dev/gvisor/pkg/fspath"
	"gvisor.dev/gvisor/pkg/sentry/vfs"
)

// IsAncestorDentry returns true if d is an ancestor of d2; that is, d is
// either d2's parent or an ancestor of d2's parent.
func genericIsAncestorDentry(d, d2 *Dentry) bool {
	for d2 != nil {
		if d2.parent == d {
			return true
		}
		if d2.parent == d2 {
			return false
		}
		d2 = d2.parent
	}
	return false
}

// ParentOrSelf returns d.parent. If d.parent is nil, ParentOrSelf returns d.
func genericParentOrSelf(d *Dentry) *Dentry {
	if d.parent != nil {
		return d.parent
	}
	return d
}

// PrependPath is a generic implementation of FilesystemImpl.PrependPath().
func genericPrependPath(vfsroot vfs.VirtualDentry, mnt *vfs.Mount, d *Dentry, b *fspath.Builder) error {
	for {
		if mnt == vfsroot.Mount() && &d.vfsd == vfsroot.Dentry() {
			return vfs.PrependPathAtVFSRootError{}
		}
		if mnt != nil && &d.vfsd == mnt.Root() {
			return nil
		}
		if d.parent == nil {
			return vfs.PrependPathAtNonMountRootError{}
		}
		b.PrependComponent(d.name)
		d = d.parent
	}
}

// DebugPathname returns a pathname to d relative to its filesystem root.
// DebugPathname does not correspond to any Linux function; it's used to
// generate dentry pathnames for debugging.
func genericDebugPathname(d *Dentry) string {
	var b fspath.Builder
	_ = genericPrependPath(vfs.VirtualDentry{}, nil, d, &b)
	return b.String()
}