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path: root/pkg/sentry/fsimpl/tmpfs/filesystem.go
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Diffstat (limited to 'pkg/sentry/fsimpl/tmpfs/filesystem.go')
-rwxr-xr-xpkg/sentry/fsimpl/tmpfs/filesystem.go249
1 files changed, 133 insertions, 116 deletions
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index 452c4e2e0..5b62f9ebb 100755
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -39,27 +39,43 @@ func (fs *filesystem) Sync(ctx context.Context) error {
//
// Preconditions: filesystem.mu must be locked. !rp.Done().
func stepLocked(rp *vfs.ResolvingPath, d *dentry) (*dentry, error) {
- if !d.inode.isDir() {
+ dir, ok := d.inode.impl.(*directory)
+ if !ok {
return nil, syserror.ENOTDIR
}
if err := d.inode.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil {
return nil, err
}
afterSymlink:
- if len(rp.Component()) > linux.NAME_MAX {
- return nil, syserror.ENAMETOOLONG
+ name := rp.Component()
+ if name == "." {
+ rp.Advance()
+ return d, nil
}
- nextVFSD, err := rp.ResolveComponent(&d.vfsd)
- if err != nil {
- return nil, err
+ if name == ".." {
+ if isRoot, err := rp.CheckRoot(&d.vfsd); err != nil {
+ return nil, err
+ } else if isRoot || d.parent == nil {
+ rp.Advance()
+ return d, nil
+ }
+ if err := rp.CheckMount(&d.parent.vfsd); err != nil {
+ return nil, err
+ }
+ rp.Advance()
+ return d.parent, nil
}
- if nextVFSD == nil {
- // Since the Dentry tree is the sole source of truth for tmpfs, if it's
- // not in the Dentry tree, it doesn't exist.
+ if len(name) > linux.NAME_MAX {
+ return nil, syserror.ENAMETOOLONG
+ }
+ child, ok := dir.childMap[name]
+ if !ok {
return nil, syserror.ENOENT
}
- next := nextVFSD.Impl().(*dentry)
- if symlink, ok := next.inode.impl.(*symlink); ok && rp.ShouldFollowSymlink() {
+ if err := rp.CheckMount(&child.vfsd); err != nil {
+ return nil, err
+ }
+ if symlink, ok := child.inode.impl.(*symlink); ok && rp.ShouldFollowSymlink() {
// TODO(gvisor.dev/issue/1197): Symlink traversals updates
// access time.
if err := rp.HandleSymlink(symlink.target); err != nil {
@@ -68,7 +84,7 @@ afterSymlink:
goto afterSymlink // don't check the current directory again
}
rp.Advance()
- return next, nil
+ return child, nil
}
// walkParentDirLocked resolves all but the last path component of rp to an
@@ -80,7 +96,7 @@ afterSymlink:
// fs/namei.c:path_parentat().
//
// Preconditions: filesystem.mu must be locked. !rp.Done().
-func walkParentDirLocked(rp *vfs.ResolvingPath, d *dentry) (*dentry, error) {
+func walkParentDirLocked(rp *vfs.ResolvingPath, d *dentry) (*directory, error) {
for !rp.Final() {
next, err := stepLocked(rp, d)
if err != nil {
@@ -88,10 +104,11 @@ func walkParentDirLocked(rp *vfs.ResolvingPath, d *dentry) (*dentry, error) {
}
d = next
}
- if !d.inode.isDir() {
+ dir, ok := d.inode.impl.(*directory)
+ if !ok {
return nil, syserror.ENOTDIR
}
- return d, nil
+ return dir, nil
}
// resolveLocked resolves rp to an existing file.
@@ -122,14 +139,14 @@ func resolveLocked(rp *vfs.ResolvingPath) (*dentry, error) {
//
// Preconditions: !rp.Done(). For the final path component in rp,
// !rp.ShouldFollowSymlink().
-func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(parent *dentry, name string) error) error {
+func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(parentDir *directory, name string) error) error {
fs.mu.Lock()
defer fs.mu.Unlock()
- parent, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
+ parentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
if err != nil {
return err
}
- if err := parent.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
+ if err := parentDir.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
return err
}
name := rp.Component()
@@ -139,19 +156,15 @@ func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(pa
if len(name) > linux.NAME_MAX {
return syserror.ENAMETOOLONG
}
- // Call parent.vfsd.Child() instead of stepLocked() or rp.ResolveChild(),
- // because if the child exists we want to return EEXIST immediately instead
- // of attempting symlink/mount traversal.
- if parent.vfsd.Child(name) != nil {
+ if _, ok := parentDir.childMap[name]; ok {
return syserror.EEXIST
}
if !dir && rp.MustBeDir() {
return syserror.ENOENT
}
- // In tmpfs, the only way to cause a dentry to be disowned is by removing
- // it from the filesystem, so this check is equivalent to checking if
- // parent has been removed.
- if parent.vfsd.IsDisowned() {
+ // tmpfs never calls VFS.InvalidateDentry(), so parentDir.dentry can only
+ // be dead if it was deleted.
+ if parentDir.dentry.vfsd.IsDead() {
return syserror.ENOENT
}
mnt := rp.Mount()
@@ -159,10 +172,10 @@ func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(pa
return err
}
defer mnt.EndWrite()
- if err := create(parent, name); err != nil {
+ if err := create(parentDir, name); err != nil {
return err
}
- parent.inode.touchCMtime()
+ parentDir.inode.touchCMtime()
return nil
}
@@ -201,17 +214,17 @@ func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op
func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) {
fs.mu.RLock()
defer fs.mu.RUnlock()
- d, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
+ dir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
if err != nil {
return nil, err
}
- d.IncRef()
- return &d.vfsd, nil
+ dir.dentry.IncRef()
+ return &dir.dentry.vfsd, nil
}
// LinkAt implements vfs.FilesystemImpl.LinkAt.
func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry) error {
- return fs.doCreateAt(rp, false /* dir */, func(parent *dentry, name string) error {
+ return fs.doCreateAt(rp, false /* dir */, func(parentDir *directory, name string) error {
if rp.Mount() != vd.Mount() {
return syserror.EXDEV
}
@@ -226,30 +239,27 @@ func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.
return syserror.EMLINK
}
d.inode.incLinksLocked()
- child := fs.newDentry(d.inode)
- parent.vfsd.InsertChild(&child.vfsd, name)
- parent.inode.impl.(*directory).childList.PushBack(child)
+ parentDir.insertChildLocked(fs.newDentry(d.inode), name)
return nil
})
}
// MkdirAt implements vfs.FilesystemImpl.MkdirAt.
func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error {
- return fs.doCreateAt(rp, true /* dir */, func(parent *dentry, name string) error {
- if parent.inode.nlink == maxLinks {
+ return fs.doCreateAt(rp, true /* dir */, func(parentDir *directory, name string) error {
+ if parentDir.inode.nlink == maxLinks {
return syserror.EMLINK
}
- parent.inode.incLinksLocked() // from child's ".."
- child := fs.newDentry(fs.newDirectory(rp.Credentials(), opts.Mode))
- parent.vfsd.InsertChild(&child.vfsd, name)
- parent.inode.impl.(*directory).childList.PushBack(child)
+ parentDir.inode.incLinksLocked() // from child's ".."
+ childDir := fs.newDirectory(rp.Credentials(), opts.Mode)
+ parentDir.insertChildLocked(&childDir.dentry, name)
return nil
})
}
// MknodAt implements vfs.FilesystemImpl.MknodAt.
func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error {
- return fs.doCreateAt(rp, false /* dir */, func(parent *dentry, name string) error {
+ return fs.doCreateAt(rp, false /* dir */, func(parentDir *directory, name string) error {
var childInode *inode
switch opts.Mode.FileType() {
case 0, linux.S_IFREG:
@@ -266,8 +276,7 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v
return syserror.EINVAL
}
child := fs.newDentry(childInode)
- parent.vfsd.InsertChild(&child.vfsd, name)
- parent.inode.impl.(*directory).childList.PushBack(child)
+ parentDir.insertChildLocked(child, name)
return nil
})
}
@@ -306,12 +315,12 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
return start.open(ctx, rp, &opts, false /* afterCreate */)
}
afterTrailingSymlink:
- parent, err := walkParentDirLocked(rp, start)
+ parentDir, err := walkParentDirLocked(rp, start)
if err != nil {
return nil, err
}
// Check for search permission in the parent directory.
- if err := parent.inode.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil {
+ if err := parentDir.inode.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil {
return nil, err
}
// Reject attempts to open directories with O_CREAT.
@@ -322,11 +331,14 @@ afterTrailingSymlink:
if name == "." || name == ".." {
return nil, syserror.EISDIR
}
+ if len(name) > linux.NAME_MAX {
+ return nil, syserror.ENAMETOOLONG
+ }
// Determine whether or not we need to create a file.
- child, err := stepLocked(rp, parent)
- if err == syserror.ENOENT {
+ child, ok := parentDir.childMap[name]
+ if !ok {
// Already checked for searchability above; now check for writability.
- if err := parent.inode.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil {
+ if err := parentDir.inode.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil {
return nil, err
}
if err := rp.Mount().CheckBeginWrite(); err != nil {
@@ -335,21 +347,26 @@ afterTrailingSymlink:
defer rp.Mount().EndWrite()
// Create and open the child.
child := fs.newDentry(fs.newRegularFile(rp.Credentials(), opts.Mode))
- parent.vfsd.InsertChild(&child.vfsd, name)
- parent.inode.impl.(*directory).childList.PushBack(child)
+ parentDir.insertChildLocked(child, name)
fd, err := child.open(ctx, rp, &opts, true)
if err != nil {
return nil, err
}
- parent.inode.touchCMtime()
+ parentDir.inode.touchCMtime()
return fd, nil
}
- if err != nil {
+ // Is the file mounted over?
+ if err := rp.CheckMount(&child.vfsd); err != nil {
return nil, err
}
// Do we need to resolve a trailing symlink?
- if !rp.Done() {
- start = parent
+ if symlink, ok := child.inode.impl.(*symlink); ok && rp.ShouldFollowSymlink() {
+ // TODO(gvisor.dev/issue/1197): Symlink traversals updates
+ // access time.
+ if err := rp.HandleSymlink(symlink.target); err != nil {
+ return nil, err
+ }
+ start = &parentDir.dentry
goto afterTrailingSymlink
}
// Open existing file.
@@ -428,7 +445,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
// Resolve newParent first to verify that it's on this Mount.
fs.mu.Lock()
defer fs.mu.Unlock()
- newParent, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
+ newParentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
if err != nil {
return err
}
@@ -445,23 +462,22 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
}
defer mnt.EndWrite()
- oldParent := oldParentVD.Dentry().Impl().(*dentry)
- if err := oldParent.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
+ oldParentDir := oldParentVD.Dentry().Impl().(*dentry).inode.impl.(*directory)
+ if err := oldParentDir.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
return err
}
- // Call vfs.Dentry.Child() instead of stepLocked() or rp.ResolveChild(),
- // because if the existing child is a symlink or mount point then we want
- // to rename over it rather than follow it.
- renamedVFSD := oldParent.vfsd.Child(oldName)
- if renamedVFSD == nil {
+ renamed, ok := oldParentDir.childMap[oldName]
+ if !ok {
return syserror.ENOENT
}
- renamed := renamedVFSD.Impl().(*dentry)
+ // Note that we don't need to call rp.CheckMount(), since if renamed is a
+ // mount point then we want to rename the mount point, not anything in the
+ // mounted filesystem.
if renamed.inode.isDir() {
- if renamed == newParent || renamedVFSD.IsAncestorOf(&newParent.vfsd) {
+ if renamed == &newParentDir.dentry || genericIsAncestorDentry(renamed, &newParentDir.dentry) {
return syserror.EINVAL
}
- if oldParent != newParent {
+ if oldParentDir != newParentDir {
// Writability is needed to change renamed's "..".
if err := renamed.inode.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil {
return err
@@ -473,18 +489,17 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
}
}
- if err := newParent.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
+ if err := newParentDir.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
return err
}
- replacedVFSD := newParent.vfsd.Child(newName)
- var replaced *dentry
- if replacedVFSD != nil {
- replaced = replacedVFSD.Impl().(*dentry)
- if replaced.inode.isDir() {
+ replaced, ok := newParentDir.childMap[newName]
+ if ok {
+ replacedDir, ok := replaced.inode.impl.(*directory)
+ if ok {
if !renamed.inode.isDir() {
return syserror.EISDIR
}
- if replaced.vfsd.HasChildren() {
+ if len(replacedDir.childMap) != 0 {
return syserror.ENOTEMPTY
}
} else {
@@ -496,11 +511,13 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
}
}
} else {
- if renamed.inode.isDir() && newParent.inode.nlink == maxLinks {
+ if renamed.inode.isDir() && newParentDir.inode.nlink == maxLinks {
return syserror.EMLINK
}
}
- if newParent.vfsd.IsDisowned() {
+ // tmpfs never calls VFS.InvalidateDentry(), so newParentDir.dentry can
+ // only be dead if it was deleted.
+ if newParentDir.dentry.vfsd.IsDead() {
return syserror.ENOENT
}
@@ -508,36 +525,38 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
// simplicity, under the assumption that applications are not intentionally
// doing noop renames expecting them to succeed where non-noop renames
// would fail.
- if renamedVFSD == replacedVFSD {
+ if renamed == replaced {
return nil
}
vfsObj := rp.VirtualFilesystem()
- oldParentDir := oldParent.inode.impl.(*directory)
- newParentDir := newParent.inode.impl.(*directory)
mntns := vfs.MountNamespaceFromContext(ctx)
defer mntns.DecRef()
- if err := vfsObj.PrepareRenameDentry(mntns, renamedVFSD, replacedVFSD); err != nil {
+ var replacedVFSD *vfs.Dentry
+ if replaced != nil {
+ replacedVFSD = &replaced.vfsd
+ }
+ if err := vfsObj.PrepareRenameDentry(mntns, &renamed.vfsd, replacedVFSD); err != nil {
return err
}
if replaced != nil {
- newParentDir.childList.Remove(replaced)
+ newParentDir.removeChildLocked(replaced)
if replaced.inode.isDir() {
- newParent.inode.decLinksLocked() // from replaced's ".."
+ newParentDir.inode.decLinksLocked() // from replaced's ".."
}
replaced.inode.decLinksLocked()
}
- oldParentDir.childList.Remove(renamed)
- newParentDir.childList.PushBack(renamed)
- if renamed.inode.isDir() {
- oldParent.inode.decLinksLocked()
- newParent.inode.incLinksLocked()
+ oldParentDir.removeChildLocked(renamed)
+ newParentDir.insertChildLocked(renamed, newName)
+ vfsObj.CommitRenameReplaceDentry(&renamed.vfsd, replacedVFSD)
+ oldParentDir.inode.touchCMtime()
+ if oldParentDir != newParentDir {
+ if renamed.inode.isDir() {
+ oldParentDir.inode.decLinksLocked()
+ newParentDir.inode.incLinksLocked()
+ }
+ newParentDir.inode.touchCMtime()
}
- oldParent.inode.touchCMtime()
- newParent.inode.touchCMtime()
renamed.inode.touchCtime()
- // TODO(gvisor.dev/issue/1197): Update timestamps and parent directory
- // sizes.
- vfsObj.CommitRenameReplaceDentry(renamedVFSD, &newParent.vfsd, newName, replacedVFSD)
return nil
}
@@ -545,11 +564,11 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error {
fs.mu.Lock()
defer fs.mu.Unlock()
- parent, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
+ parentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
if err != nil {
return err
}
- if err := parent.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
+ if err := parentDir.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
return err
}
name := rp.Component()
@@ -559,15 +578,15 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
if name == ".." {
return syserror.ENOTEMPTY
}
- childVFSD := parent.vfsd.Child(name)
- if childVFSD == nil {
+ child, ok := parentDir.childMap[name]
+ if !ok {
return syserror.ENOENT
}
- child := childVFSD.Impl().(*dentry)
- if !child.inode.isDir() {
+ childDir, ok := child.inode.impl.(*directory)
+ if !ok {
return syserror.ENOTDIR
}
- if childVFSD.HasChildren() {
+ if len(childDir.childMap) != 0 {
return syserror.ENOTEMPTY
}
mnt := rp.Mount()
@@ -578,14 +597,14 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
vfsObj := rp.VirtualFilesystem()
mntns := vfs.MountNamespaceFromContext(ctx)
defer mntns.DecRef()
- if err := vfsObj.PrepareDeleteDentry(mntns, childVFSD); err != nil {
+ if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil {
return err
}
- parent.inode.impl.(*directory).childList.Remove(child)
- parent.inode.decLinksLocked() // from child's ".."
+ parentDir.removeChildLocked(child)
+ parentDir.inode.decLinksLocked() // from child's ".."
child.inode.decLinksLocked()
- vfsObj.CommitDeleteDentry(childVFSD)
- parent.inode.touchCMtime()
+ vfsObj.CommitDeleteDentry(&child.vfsd)
+ parentDir.inode.touchCMtime()
return nil
}
@@ -627,10 +646,9 @@ func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linu
// SymlinkAt implements vfs.FilesystemImpl.SymlinkAt.
func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, target string) error {
- return fs.doCreateAt(rp, false /* dir */, func(parent *dentry, name string) error {
+ return fs.doCreateAt(rp, false /* dir */, func(parentDir *directory, name string) error {
child := fs.newDentry(fs.newSymlink(rp.Credentials(), target))
- parent.vfsd.InsertChild(&child.vfsd, name)
- parent.inode.impl.(*directory).childList.PushBack(child)
+ parentDir.insertChildLocked(child, name)
return nil
})
}
@@ -639,22 +657,21 @@ func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ
func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error {
fs.mu.Lock()
defer fs.mu.Unlock()
- parent, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
+ parentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry))
if err != nil {
return err
}
- if err := parent.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
+ if err := parentDir.inode.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil {
return err
}
name := rp.Component()
if name == "." || name == ".." {
return syserror.EISDIR
}
- childVFSD := parent.vfsd.Child(name)
- if childVFSD == nil {
+ child, ok := parentDir.childMap[name]
+ if !ok {
return syserror.ENOENT
}
- child := childVFSD.Impl().(*dentry)
if child.inode.isDir() {
return syserror.EISDIR
}
@@ -669,13 +686,13 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error
vfsObj := rp.VirtualFilesystem()
mntns := vfs.MountNamespaceFromContext(ctx)
defer mntns.DecRef()
- if err := vfsObj.PrepareDeleteDentry(mntns, childVFSD); err != nil {
+ if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil {
return err
}
- parent.inode.impl.(*directory).childList.Remove(child)
+ parentDir.removeChildLocked(child)
child.inode.decLinksLocked()
- vfsObj.CommitDeleteDentry(childVFSD)
- parent.inode.touchCMtime()
+ vfsObj.CommitDeleteDentry(&child.vfsd)
+ parentDir.inode.touchCMtime()
return nil
}
@@ -743,5 +760,5 @@ func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath,
func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDentry, b *fspath.Builder) error {
fs.mu.RLock()
defer fs.mu.RUnlock()
- return vfs.GenericPrependPath(vfsroot, vd, b)
+ return genericPrependPath(vfsroot, vd.Mount(), vd.Dentry().Impl().(*dentry), b)
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 20:31:28 +0000