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package overlay
import (
"gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/sentry/vfs"
)
// We need to define an interface instead of using atomic.Pointer because
// the Dentry type gets removed during code generation and the compiler
// complains about the unused sync/atomic type.
type genericatomicptr interface {
Load() *dentry
}
// 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 {
parent := d2.parent.Load()
if parent == d {
return true
}
if parent == d2 {
return false
}
d2 = parent
}
return false
}
// IsDescendant returns true if vd is a descendant of vfsroot or if vd and
// vfsroot are the same dentry.
func genericIsDescendant(vfsroot *vfs.Dentry, d *dentry) bool {
for d != nil && &d.vfsd != vfsroot {
d = d.parent.Load()
}
return d != nil
}
// ParentOrSelf returns d.parent. If d.parent is nil, ParentOrSelf returns d.
func genericParentOrSelf(d *dentry) *dentry {
if parent := d.parent.Load(); parent != nil {
return 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
}
parent := d.parent.Load()
if parent == nil {
return vfs.PrependPathAtNonMountRootError{}
}
b.PrependComponent(d.name)
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()
}
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