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Diffstat (limited to 'pkg/sentry/vfs/filesystem.go')
| -rw-r--r-- | pkg/sentry/vfs/filesystem.go | 155 |
1 files changed, 0 insertions, 155 deletions
diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go deleted file mode 100644 index 7a074b718..000000000 --- a/pkg/sentry/vfs/filesystem.go +++ /dev/null @@ -1,155 +0,0 @@ -// Copyright 2019 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package vfs - -import ( - "sync/atomic" - - "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/sentry/context" -) - -// A Filesystem is a tree of nodes represented by Dentries, which forms part of -// a VirtualFilesystem. -// -// Filesystems are reference-counted. Unless otherwise specified, all -// Filesystem methods require that a reference is held. -// -// Filesystem is analogous to Linux's struct super_block. -type Filesystem struct { - // refs is the reference count. refs is accessed using atomic memory - // operations. - refs int64 - - // impl is the FilesystemImpl associated with this Filesystem. impl is - // immutable. This should be the last field in Dentry. - impl FilesystemImpl -} - -// Init must be called before first use of fs. -func (fs *Filesystem) Init(impl FilesystemImpl) { - fs.refs = 1 - fs.impl = impl -} - -// Impl returns the FilesystemImpl associated with fs. -func (fs *Filesystem) Impl() FilesystemImpl { - return fs.impl -} - -func (fs *Filesystem) incRef() { - if atomic.AddInt64(&fs.refs, 1) <= 1 { - panic("Filesystem.incRef() called without holding a reference") - } -} - -func (fs *Filesystem) decRef() { - if refs := atomic.AddInt64(&fs.refs, -1); refs == 0 { - fs.impl.Release() - } else if refs < 0 { - panic("Filesystem.decRef() called without holding a reference") - } -} - -// FilesystemImpl contains implementation details for a Filesystem. -// Implementations of FilesystemImpl should contain their associated Filesystem -// by value as their first field. -// -// All methods that take a ResolvingPath must resolve the path before -// performing any other checks, including rejection of the operation if not -// supported by the FilesystemImpl. This is because the final FilesystemImpl -// (responsible for actually implementing the operation) isn't known until path -// resolution is complete. -// -// For all methods that take or return linux.Statx, Statx.Uid and Statx.Gid -// should be interpreted as IDs in the root UserNamespace (i.e. as auth.KUID -// and auth.KGID respectively). -// -// FilesystemImpl combines elements of Linux's struct super_operations and -// struct inode_operations, for reasons described in the documentation for -// Dentry. -type FilesystemImpl interface { - // Release is called when the associated Filesystem reaches zero - // references. - Release() - - // Sync "causes all pending modifications to filesystem metadata and cached - // file data to be written to the underlying [filesystem]", as by syncfs(2). - Sync(ctx context.Context) error - - // GetDentryAt returns a Dentry representing the file at rp. A reference is - // taken on the returned Dentry. - // - // GetDentryAt does not correspond directly to a Linux syscall; it is used - // in the implementation of: - // - // - Syscalls that need to resolve two paths: rename(), renameat(), - // renameat2(), link(), linkat(). - // - // - Syscalls that need to refer to a filesystem position outside the - // context of a file description: chdir(), fchdir(), chroot(), mount(), - // umount(). - GetDentryAt(ctx context.Context, rp *ResolvingPath, opts GetDentryOptions) (*Dentry, error) - - // LinkAt creates a hard link at rp representing the same file as vd. It - // does not take ownership of references on vd. - // - // The implementation is responsible for checking that vd.Mount() == - // rp.Mount(), and that vd does not represent a directory. - LinkAt(ctx context.Context, rp *ResolvingPath, vd VirtualDentry) error - - // MkdirAt creates a directory at rp. - MkdirAt(ctx context.Context, rp *ResolvingPath, opts MkdirOptions) error - - // MknodAt creates a regular file, device special file, or named pipe at - // rp. - MknodAt(ctx context.Context, rp *ResolvingPath, opts MknodOptions) error - - // OpenAt returns an FileDescription providing access to the file at rp. A - // reference is taken on the returned FileDescription. - OpenAt(ctx context.Context, rp *ResolvingPath, opts OpenOptions) (*FileDescription, error) - - // ReadlinkAt returns the target of the symbolic link at rp. - ReadlinkAt(ctx context.Context, rp *ResolvingPath) (string, error) - - // RenameAt renames the Dentry represented by vd to rp. It does not take - // ownership of references on vd. - // - // The implementation is responsible for checking that vd.Mount() == - // rp.Mount(). - RenameAt(ctx context.Context, rp *ResolvingPath, vd VirtualDentry, opts RenameOptions) error - - // RmdirAt removes the directory at rp. - RmdirAt(ctx context.Context, rp *ResolvingPath) error - - // SetStatAt updates metadata for the file at the given path. - SetStatAt(ctx context.Context, rp *ResolvingPath, opts SetStatOptions) error - - // StatAt returns metadata for the file at rp. - StatAt(ctx context.Context, rp *ResolvingPath, opts StatOptions) (linux.Statx, error) - - // StatFSAt returns metadata for the filesystem containing the file at rp. - // (This method takes a path because a FilesystemImpl may consist of any - // number of constituent filesystems.) - StatFSAt(ctx context.Context, rp *ResolvingPath) (linux.Statfs, error) - - // SymlinkAt creates a symbolic link at rp referring to the given target. - SymlinkAt(ctx context.Context, rp *ResolvingPath, target string) error - - // UnlinkAt removes the non-directory file at rp. - UnlinkAt(ctx context.Context, rp *ResolvingPath) error - - // TODO: d_path(); extended attributes; inotify_add_watch(); bind() -} |