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Diffstat (limited to 'pkg/sentry/fsimpl/gofer/filesystem.go')
-rw-r--r--pkg/sentry/fsimpl/gofer/filesystem.go1103
1 files changed, 0 insertions, 1103 deletions
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
deleted file mode 100644
index 38e4cdbc5..000000000
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ /dev/null
@@ -1,1103 +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 gofer
-
-import (
- "sync"
-
- "gvisor.dev/gvisor/pkg/abi/linux"
- "gvisor.dev/gvisor/pkg/context"
- "gvisor.dev/gvisor/pkg/fspath"
- "gvisor.dev/gvisor/pkg/p9"
- "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
- "gvisor.dev/gvisor/pkg/sentry/vfs"
- "gvisor.dev/gvisor/pkg/syserror"
-)
-
-// Sync implements vfs.FilesystemImpl.Sync.
-func (fs *filesystem) Sync(ctx context.Context) error {
- // Snapshot current dentries and special files.
- fs.syncMu.Lock()
- ds := make([]*dentry, 0, len(fs.dentries))
- for d := range fs.dentries {
- ds = append(ds, d)
- }
- sffds := make([]*specialFileFD, 0, len(fs.specialFileFDs))
- for sffd := range fs.specialFileFDs {
- sffds = append(sffds, sffd)
- }
- fs.syncMu.Unlock()
-
- // Return the first error we encounter, but sync everything we can
- // regardless.
- var retErr error
-
- // Sync regular files.
- for _, d := range ds {
- if !d.TryIncRef() {
- continue
- }
- err := d.syncSharedHandle(ctx)
- d.DecRef()
- if err != nil && retErr == nil {
- retErr = err
- }
- }
-
- // Sync special files, which may be writable but do not use dentry shared
- // handles (so they won't be synced by the above).
- for _, sffd := range sffds {
- if !sffd.vfsfd.TryIncRef() {
- continue
- }
- err := sffd.Sync(ctx)
- sffd.vfsfd.DecRef()
- if err != nil && retErr == nil {
- retErr = err
- }
- }
-
- return retErr
-}
-
-// maxFilenameLen is the maximum length of a filename. This is dictated by 9P's
-// encoding of strings, which uses 2 bytes for the length prefix.
-const maxFilenameLen = (1 << 16) - 1
-
-// dentrySlicePool is a pool of *[]*dentry used to store dentries for which
-// dentry.checkCachingLocked() must be called. The pool holds pointers to
-// slices because Go lacks generics, so sync.Pool operates on interface{}, so
-// every call to (what should be) sync.Pool<[]*dentry>.Put() allocates a copy
-// of the slice header on the heap.
-var dentrySlicePool = sync.Pool{
- New: func() interface{} {
- ds := make([]*dentry, 0, 4) // arbitrary non-zero initial capacity
- return &ds
- },
-}
-
-func appendDentry(ds *[]*dentry, d *dentry) *[]*dentry {
- if ds == nil {
- ds = dentrySlicePool.Get().(*[]*dentry)
- }
- *ds = append(*ds, d)
- return ds
-}
-
-// Preconditions: ds != nil.
-func putDentrySlice(ds *[]*dentry) {
- // Allow dentries to be GC'd.
- for i := range *ds {
- (*ds)[i] = nil
- }
- *ds = (*ds)[:0]
- dentrySlicePool.Put(ds)
-}
-
-// stepLocked resolves rp.Component() to an existing file, starting from the
-// given directory.
-//
-// Dentries which may become cached as a result of the traversal are appended
-// to *ds.
-//
-// Preconditions: fs.renameMu must be locked. d.dirMu must be locked.
-// !rp.Done(). If fs.opts.interop == InteropModeShared, then d's cached
-// metadata must be up to date.
-func (fs *filesystem) stepLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, ds **[]*dentry) (*dentry, error) {
- if !d.isDir() {
- return nil, syserror.ENOTDIR
- }
- if err := d.checkPermissions(rp.Credentials(), vfs.MayExec, true); err != nil {
- return nil, err
- }
-afterSymlink:
- name := rp.Component()
- if name == "." {
- rp.Advance()
- return d, nil
- }
- if name == ".." {
- parentVFSD, err := rp.ResolveParent(&d.vfsd)
- if err != nil {
- return nil, err
- }
- parent := parentVFSD.Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- // We must assume that parentVFSD is correct, because if d has been
- // moved elsewhere in the remote filesystem so that its parent has
- // changed, we have no way of determining its new parent's location
- // in the filesystem. Get updated metadata for parentVFSD.
- _, attrMask, attr, err := parent.file.getAttr(ctx, dentryAttrMask())
- if err != nil {
- return nil, err
- }
- parent.updateFromP9Attrs(attrMask, &attr)
- }
- rp.Advance()
- return parent, nil
- }
- childVFSD, err := rp.ResolveChild(&d.vfsd, name)
- if err != nil {
- return nil, err
- }
- // FIXME(jamieliu): Linux performs revalidation before mount lookup
- // (fs/namei.c:lookup_fast() => __d_lookup_rcu(), d_revalidate(),
- // __follow_mount_rcu()).
- child, err := fs.revalidateChildLocked(ctx, rp.VirtualFilesystem(), d, name, childVFSD, ds)
- if err != nil {
- return nil, err
- }
- if child == nil {
- return nil, syserror.ENOENT
- }
- if child.isSymlink() && rp.ShouldFollowSymlink() {
- target, err := child.readlink(ctx, rp.Mount())
- if err != nil {
- return nil, err
- }
- if err := rp.HandleSymlink(target); err != nil {
- return nil, err
- }
- goto afterSymlink // don't check the current directory again
- }
- rp.Advance()
- return child, nil
-}
-
-// revalidateChildLocked must be called after a call to parent.vfsd.Child(name)
-// or vfs.ResolvingPath.ResolveChild(name) returns childVFSD (which may be
-// nil) to verify that the returned child (or lack thereof) is correct. If no file
-// exists at name, revalidateChildLocked returns (nil, nil).
-//
-// Preconditions: fs.renameMu must be locked. parent.dirMu must be locked.
-// parent.isDir(). name is not "." or "..".
-//
-// Postconditions: If revalidateChildLocked returns a non-nil dentry, its
-// cached metadata is up to date.
-func (fs *filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.VirtualFilesystem, parent *dentry, name string, childVFSD *vfs.Dentry, ds **[]*dentry) (*dentry, error) {
- if childVFSD != nil && fs.opts.interop != InteropModeShared {
- // We have a cached dentry that is assumed to be correct.
- return childVFSD.Impl().(*dentry), nil
- }
- // We either don't have a cached dentry or need to verify that it's still
- // correct, either of which requires a remote lookup. Check if this name is
- // valid before performing the lookup.
- if len(name) > maxFilenameLen {
- return nil, syserror.ENAMETOOLONG
- }
- // Check if we've already cached this lookup with a negative result.
- if _, ok := parent.negativeChildren[name]; ok {
- return nil, nil
- }
- // Perform the remote lookup.
- qid, file, attrMask, attr, err := parent.file.walkGetAttrOne(ctx, name)
- if err != nil && err != syserror.ENOENT {
- return nil, err
- }
- if childVFSD != nil {
- child := childVFSD.Impl().(*dentry)
- if !file.isNil() && qid.Path == child.ino {
- // The file at this path hasn't changed. Just update cached
- // metadata.
- file.close(ctx)
- child.updateFromP9Attrs(attrMask, &attr)
- return child, nil
- }
- // The file at this path has changed or no longer exists. Remove
- // the stale dentry from the tree, and re-evaluate its caching
- // status (i.e. if it has 0 references, drop it).
- vfsObj.ForceDeleteDentry(childVFSD)
- *ds = appendDentry(*ds, child)
- childVFSD = nil
- }
- if file.isNil() {
- // No file exists at this path now. Cache the negative lookup if
- // allowed.
- if fs.opts.interop != InteropModeShared {
- parent.cacheNegativeChildLocked(name)
- }
- return nil, nil
- }
- // Create a new dentry representing the file.
- child, err := fs.newDentry(ctx, file, qid, attrMask, &attr)
- if err != nil {
- file.close(ctx)
- return nil, err
- }
- parent.IncRef() // reference held by child on its parent
- parent.vfsd.InsertChild(&child.vfsd, name)
- // For now, child has 0 references, so our caller should call
- // child.checkCachingLocked().
- *ds = appendDentry(*ds, child)
- return child, nil
-}
-
-// walkParentDirLocked resolves all but the last path component of rp to an
-// existing directory, starting from the given directory (which is usually
-// rp.Start().Impl().(*dentry)). It does not check that the returned directory
-// is searchable by the provider of rp.
-//
-// Preconditions: fs.renameMu must be locked. !rp.Done(). If fs.opts.interop ==
-// InteropModeShared, then d's cached metadata must be up to date.
-func (fs *filesystem) walkParentDirLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, ds **[]*dentry) (*dentry, error) {
- for !rp.Final() {
- d.dirMu.Lock()
- next, err := fs.stepLocked(ctx, rp, d, ds)
- d.dirMu.Unlock()
- if err != nil {
- return nil, err
- }
- d = next
- }
- if !d.isDir() {
- return nil, syserror.ENOTDIR
- }
- return d, nil
-}
-
-// resolveLocked resolves rp to an existing file.
-//
-// Preconditions: fs.renameMu must be locked.
-func (fs *filesystem) resolveLocked(ctx context.Context, rp *vfs.ResolvingPath, ds **[]*dentry) (*dentry, error) {
- d := rp.Start().Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- // Get updated metadata for rp.Start() as required by fs.stepLocked().
- if err := d.updateFromGetattr(ctx); err != nil {
- return nil, err
- }
- }
- for !rp.Done() {
- d.dirMu.Lock()
- next, err := fs.stepLocked(ctx, rp, d, ds)
- d.dirMu.Unlock()
- if err != nil {
- return nil, err
- }
- d = next
- }
- if rp.MustBeDir() && !d.isDir() {
- return nil, syserror.ENOTDIR
- }
- return d, nil
-}
-
-// doCreateAt checks that creating a file at rp is permitted, then invokes
-// create to do so.
-//
-// Preconditions: !rp.Done(). For the final path component in rp,
-// !rp.ShouldFollowSymlink().
-func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir bool, create func(parent *dentry, name string) error) error {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- start := rp.Start().Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- // Get updated metadata for start as required by
- // fs.walkParentDirLocked().
- if err := start.updateFromGetattr(ctx); err != nil {
- return err
- }
- }
- parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds)
- if err != nil {
- return err
- }
- if err := parent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec, true); err != nil {
- return err
- }
- if parent.isDeleted() {
- return syserror.ENOENT
- }
- name := rp.Component()
- if name == "." || name == ".." {
- return syserror.EEXIST
- }
- if len(name) > maxFilenameLen {
- return syserror.ENAMETOOLONG
- }
- if !dir && rp.MustBeDir() {
- return syserror.ENOENT
- }
- mnt := rp.Mount()
- if err := mnt.CheckBeginWrite(); err != nil {
- return err
- }
- defer mnt.EndWrite()
- parent.dirMu.Lock()
- defer parent.dirMu.Unlock()
- if fs.opts.interop == InteropModeShared {
- // The existence of a dentry at name would be inconclusive because the
- // file it represents may have been deleted from the remote filesystem,
- // so we would need to make an RPC to revalidate the dentry. Just
- // attempt the file creation RPC instead. If a file does exist, the RPC
- // will fail with EEXIST like we would have. If the RPC succeeds, and a
- // stale dentry exists, the dentry will fail revalidation next time
- // it's used.
- return create(parent, name)
- }
- if parent.vfsd.Child(name) != nil {
- return syserror.EEXIST
- }
- // No cached dentry exists; however, there might still be an existing file
- // at name. As above, we attempt the file creation RPC anyway.
- if err := create(parent, name); err != nil {
- return err
- }
- parent.touchCMtime(ctx)
- delete(parent.negativeChildren, name)
- parent.dirents = nil
- return nil
-}
-
-// Preconditions: !rp.Done().
-func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir bool) error {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- start := rp.Start().Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- // Get updated metadata for start as required by
- // fs.walkParentDirLocked().
- if err := start.updateFromGetattr(ctx); err != nil {
- return err
- }
- }
- parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds)
- if err != nil {
- return err
- }
- if err := parent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec, true); err != nil {
- return err
- }
- if err := rp.Mount().CheckBeginWrite(); err != nil {
- return err
- }
- defer rp.Mount().EndWrite()
-
- name := rp.Component()
- if dir {
- if name == "." {
- return syserror.EINVAL
- }
- if name == ".." {
- return syserror.ENOTEMPTY
- }
- } else {
- if name == "." || name == ".." {
- return syserror.EISDIR
- }
- }
- vfsObj := rp.VirtualFilesystem()
- mntns := vfs.MountNamespaceFromContext(ctx)
- defer mntns.DecRef()
- parent.dirMu.Lock()
- defer parent.dirMu.Unlock()
- childVFSD := parent.vfsd.Child(name)
- var child *dentry
- // We only need a dentry representing the file at name if it can be a mount
- // point. If childVFSD is nil, then it can't be a mount point. If childVFSD
- // is non-nil but stale, the actual file can't be a mount point either; we
- // detect this case by just speculatively calling PrepareDeleteDentry and
- // only revalidating the dentry if that fails (indicating that the existing
- // dentry is a mount point).
- if childVFSD != nil {
- child = childVFSD.Impl().(*dentry)
- if err := vfsObj.PrepareDeleteDentry(mntns, childVFSD); err != nil {
- child, err = fs.revalidateChildLocked(ctx, vfsObj, parent, name, childVFSD, &ds)
- if err != nil {
- return err
- }
- if child != nil {
- childVFSD = &child.vfsd
- if err := vfsObj.PrepareDeleteDentry(mntns, childVFSD); err != nil {
- return err
- }
- } else {
- childVFSD = nil
- }
- }
- } else if _, ok := parent.negativeChildren[name]; ok {
- return syserror.ENOENT
- }
- flags := uint32(0)
- if dir {
- if child != nil && !child.isDir() {
- return syserror.ENOTDIR
- }
- flags = linux.AT_REMOVEDIR
- } else {
- if child != nil && child.isDir() {
- return syserror.EISDIR
- }
- if rp.MustBeDir() {
- return syserror.ENOTDIR
- }
- }
- err = parent.file.unlinkAt(ctx, name, flags)
- if err != nil {
- if childVFSD != nil {
- vfsObj.AbortDeleteDentry(childVFSD)
- }
- return err
- }
- if fs.opts.interop != InteropModeShared {
- parent.touchCMtime(ctx)
- parent.cacheNegativeChildLocked(name)
- parent.dirents = nil
- }
- if child != nil {
- child.setDeleted()
- vfsObj.CommitDeleteDentry(childVFSD)
- ds = appendDentry(ds, child)
- }
- return nil
-}
-
-// renameMuRUnlockAndCheckCaching calls fs.renameMu.RUnlock(), then calls
-// dentry.checkCachingLocked on all dentries in *ds with fs.renameMu locked for
-// writing.
-//
-// ds is a pointer-to-pointer since defer evaluates its arguments immediately,
-// but dentry slices are allocated lazily, and it's much easier to say "defer
-// fs.renameMuRUnlockAndCheckCaching(&ds)" than "defer func() {
-// fs.renameMuRUnlockAndCheckCaching(ds) }()" to work around this.
-func (fs *filesystem) renameMuRUnlockAndCheckCaching(ds **[]*dentry) {
- fs.renameMu.RUnlock()
- if *ds == nil {
- return
- }
- if len(**ds) != 0 {
- fs.renameMu.Lock()
- for _, d := range **ds {
- d.checkCachingLocked()
- }
- fs.renameMu.Unlock()
- }
- putDentrySlice(*ds)
-}
-
-func (fs *filesystem) renameMuUnlockAndCheckCaching(ds **[]*dentry) {
- if *ds == nil {
- fs.renameMu.Unlock()
- return
- }
- for _, d := range **ds {
- d.checkCachingLocked()
- }
- fs.renameMu.Unlock()
- putDentrySlice(*ds)
-}
-
-// AccessAt implements vfs.Filesystem.Impl.AccessAt.
-func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return err
- }
- return d.checkPermissions(creds, ats, d.isDir())
-}
-
-// GetDentryAt implements vfs.FilesystemImpl.GetDentryAt.
-func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return nil, err
- }
- if opts.CheckSearchable {
- if !d.isDir() {
- return nil, syserror.ENOTDIR
- }
- if err := d.checkPermissions(rp.Credentials(), vfs.MayExec, true); err != nil {
- return nil, err
- }
- }
- d.IncRef()
- return &d.vfsd, nil
-}
-
-// GetParentDentryAt implements vfs.FilesystemImpl.GetParentDentryAt.
-func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- start := rp.Start().Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- // Get updated metadata for start as required by
- // fs.walkParentDirLocked().
- if err := start.updateFromGetattr(ctx); err != nil {
- return nil, err
- }
- }
- d, err := fs.walkParentDirLocked(ctx, rp, start, &ds)
- if err != nil {
- return nil, err
- }
- d.IncRef()
- return &d.vfsd, nil
-}
-
-// LinkAt implements vfs.FilesystemImpl.LinkAt.
-func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry) error {
- return fs.doCreateAt(ctx, rp, false /* dir */, func(parent *dentry, childName string) error {
- if rp.Mount() != vd.Mount() {
- return syserror.EXDEV
- }
- // 9P2000.L supports hard links, but we don't.
- return syserror.EPERM
- })
-}
-
-// MkdirAt implements vfs.FilesystemImpl.MkdirAt.
-func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error {
- return fs.doCreateAt(ctx, rp, true /* dir */, func(parent *dentry, name string) error {
- creds := rp.Credentials()
- _, err := parent.file.mkdir(ctx, name, (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
- return err
- })
-}
-
-// MknodAt implements vfs.FilesystemImpl.MknodAt.
-func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error {
- return fs.doCreateAt(ctx, rp, false /* dir */, func(parent *dentry, name string) error {
- creds := rp.Credentials()
- _, err := parent.file.mknod(ctx, name, (p9.FileMode)(opts.Mode), opts.DevMajor, opts.DevMinor, (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
- return err
- })
-}
-
-// OpenAt implements vfs.FilesystemImpl.OpenAt.
-func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
- // Reject O_TMPFILE, which is not supported; supporting it correctly in the
- // presence of other remote filesystem users requires remote filesystem
- // support, and it isn't clear that there's any way to implement this in
- // 9P.
- if opts.Flags&linux.O_TMPFILE != 0 {
- return nil, syserror.EOPNOTSUPP
- }
- mayCreate := opts.Flags&linux.O_CREAT != 0
- mustCreate := opts.Flags&(linux.O_CREAT|linux.O_EXCL) == (linux.O_CREAT | linux.O_EXCL)
-
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
-
- start := rp.Start().Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- // Get updated metadata for start as required by fs.stepLocked().
- if err := start.updateFromGetattr(ctx); err != nil {
- return nil, err
- }
- }
- if rp.Done() {
- return start.openLocked(ctx, rp, &opts)
- }
-
-afterTrailingSymlink:
- parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds)
- if err != nil {
- return nil, err
- }
- // Check for search permission in the parent directory.
- if err := parent.checkPermissions(rp.Credentials(), vfs.MayExec, true); err != nil {
- return nil, err
- }
- // Determine whether or not we need to create a file.
- parent.dirMu.Lock()
- child, err := fs.stepLocked(ctx, rp, parent, &ds)
- if err == syserror.ENOENT && mayCreate {
- fd, err := parent.createAndOpenChildLocked(ctx, rp, &opts)
- parent.dirMu.Unlock()
- return fd, err
- }
- if err != nil {
- parent.dirMu.Unlock()
- return nil, err
- }
- // Open existing child or follow symlink.
- parent.dirMu.Unlock()
- if mustCreate {
- return nil, syserror.EEXIST
- }
- if child.isSymlink() && rp.ShouldFollowSymlink() {
- target, err := child.readlink(ctx, rp.Mount())
- if err != nil {
- return nil, err
- }
- if err := rp.HandleSymlink(target); err != nil {
- return nil, err
- }
- start = parent
- goto afterTrailingSymlink
- }
- return child.openLocked(ctx, rp, &opts)
-}
-
-// Preconditions: fs.renameMu must be locked.
-func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
- ats := vfs.AccessTypesForOpenFlags(opts)
- if err := d.checkPermissions(rp.Credentials(), ats, d.isDir()); err != nil {
- return nil, err
- }
- mnt := rp.Mount()
- filetype := d.fileType()
- switch {
- case filetype == linux.S_IFREG && !d.fs.opts.regularFilesUseSpecialFileFD:
- if err := d.ensureSharedHandle(ctx, ats&vfs.MayRead != 0, ats&vfs.MayWrite != 0, opts.Flags&linux.O_TRUNC != 0); err != nil {
- return nil, err
- }
- fd := &regularFileFD{}
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{
- AllowDirectIO: true,
- }); err != nil {
- return nil, err
- }
- return &fd.vfsfd, nil
- case filetype == linux.S_IFDIR:
- // Can't open directories with O_CREAT.
- if opts.Flags&linux.O_CREAT != 0 {
- return nil, syserror.EISDIR
- }
- // Can't open directories writably.
- if ats&vfs.MayWrite != 0 {
- return nil, syserror.EISDIR
- }
- if opts.Flags&linux.O_DIRECT != 0 {
- return nil, syserror.EINVAL
- }
- if err := d.ensureSharedHandle(ctx, ats&vfs.MayRead != 0, false /* write */, false /* trunc */); err != nil {
- return nil, err
- }
- fd := &directoryFD{}
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
- return nil, err
- }
- return &fd.vfsfd, nil
- case filetype == linux.S_IFLNK:
- // Can't open symlinks without O_PATH (which is unimplemented).
- return nil, syserror.ELOOP
- default:
- if opts.Flags&linux.O_DIRECT != 0 {
- return nil, syserror.EINVAL
- }
- h, err := openHandle(ctx, d.file, ats&vfs.MayRead != 0, ats&vfs.MayWrite != 0, opts.Flags&linux.O_TRUNC != 0)
- if err != nil {
- return nil, err
- }
- fd := &specialFileFD{
- handle: h,
- }
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
- h.close(ctx)
- return nil, err
- }
- return &fd.vfsfd, nil
- }
-}
-
-// Preconditions: d.fs.renameMu must be locked. d.dirMu must be locked.
-func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
- if err := d.checkPermissions(rp.Credentials(), vfs.MayWrite, true); err != nil {
- return nil, err
- }
- if d.isDeleted() {
- return nil, syserror.ENOENT
- }
- mnt := rp.Mount()
- if err := mnt.CheckBeginWrite(); err != nil {
- return nil, err
- }
- defer mnt.EndWrite()
-
- // 9P2000.L's lcreate takes a fid representing the parent directory, and
- // converts it into an open fid representing the created file, so we need
- // to duplicate the directory fid first.
- _, dirfile, err := d.file.walk(ctx, nil)
- if err != nil {
- return nil, err
- }
- creds := rp.Credentials()
- name := rp.Component()
- fdobj, openFile, createQID, _, err := dirfile.create(ctx, name, (p9.OpenFlags)(opts.Flags), (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
- if err != nil {
- dirfile.close(ctx)
- return nil, err
- }
- // Then we need to walk to the file we just created to get a non-open fid
- // representing it, and to get its metadata. This must use d.file since, as
- // explained above, dirfile was invalidated by dirfile.Create().
- walkQID, nonOpenFile, attrMask, attr, err := d.file.walkGetAttrOne(ctx, name)
- if err != nil {
- openFile.close(ctx)
- if fdobj != nil {
- fdobj.Close()
- }
- return nil, err
- }
- // Sanity-check that we walked to the file we created.
- if createQID.Path != walkQID.Path {
- // Probably due to concurrent remote filesystem mutation?
- ctx.Warningf("gofer.dentry.createAndOpenChildLocked: created file has QID %v before walk, QID %v after (interop=%v)", createQID, walkQID, d.fs.opts.interop)
- nonOpenFile.close(ctx)
- openFile.close(ctx)
- if fdobj != nil {
- fdobj.Close()
- }
- return nil, syserror.EAGAIN
- }
-
- // Construct the new dentry.
- child, err := d.fs.newDentry(ctx, nonOpenFile, createQID, attrMask, &attr)
- if err != nil {
- nonOpenFile.close(ctx)
- openFile.close(ctx)
- if fdobj != nil {
- fdobj.Close()
- }
- return nil, err
- }
- // Incorporate the fid that was opened by lcreate.
- useRegularFileFD := child.fileType() == linux.S_IFREG && !d.fs.opts.regularFilesUseSpecialFileFD
- if useRegularFileFD {
- child.handleMu.Lock()
- child.handle.file = openFile
- if fdobj != nil {
- child.handle.fd = int32(fdobj.Release())
- }
- child.handleReadable = vfs.MayReadFileWithOpenFlags(opts.Flags)
- child.handleWritable = vfs.MayWriteFileWithOpenFlags(opts.Flags)
- child.handleMu.Unlock()
- }
- // Take a reference on the new dentry to be held by the new file
- // description. (This reference also means that the new dentry is not
- // eligible for caching yet, so we don't need to append to a dentry slice.)
- child.refs = 1
- // Insert the dentry into the tree.
- d.IncRef() // reference held by child on its parent d
- d.vfsd.InsertChild(&child.vfsd, name)
- if d.fs.opts.interop != InteropModeShared {
- d.touchCMtime(ctx)
- delete(d.negativeChildren, name)
- d.dirents = nil
- }
-
- // Finally, construct a file description representing the created file.
- var childVFSFD *vfs.FileDescription
- mnt.IncRef()
- if useRegularFileFD {
- fd := &regularFileFD{}
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{
- AllowDirectIO: true,
- }); err != nil {
- return nil, err
- }
- childVFSFD = &fd.vfsfd
- } else {
- fd := &specialFileFD{
- handle: handle{
- file: openFile,
- fd: -1,
- },
- }
- if fdobj != nil {
- fd.handle.fd = int32(fdobj.Release())
- }
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
- fd.handle.close(ctx)
- return nil, err
- }
- childVFSFD = &fd.vfsfd
- }
- return childVFSFD, nil
-}
-
-// ReadlinkAt implements vfs.FilesystemImpl.ReadlinkAt.
-func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return "", err
- }
- if !d.isSymlink() {
- return "", syserror.EINVAL
- }
- return d.readlink(ctx, rp.Mount())
-}
-
-// RenameAt implements vfs.FilesystemImpl.RenameAt.
-func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldParentVD vfs.VirtualDentry, oldName string, opts vfs.RenameOptions) error {
- if opts.Flags != 0 {
- // Requires 9P support.
- return syserror.EINVAL
- }
-
- var ds *[]*dentry
- fs.renameMu.Lock()
- defer fs.renameMuUnlockAndCheckCaching(&ds)
- newParent, err := fs.walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry), &ds)
- if err != nil {
- return err
- }
- newName := rp.Component()
- if newName == "." || newName == ".." {
- return syserror.EBUSY
- }
- mnt := rp.Mount()
- if mnt != oldParentVD.Mount() {
- return syserror.EXDEV
- }
- if err := mnt.CheckBeginWrite(); err != nil {
- return err
- }
- defer mnt.EndWrite()
-
- oldParent := oldParentVD.Dentry().Impl().(*dentry)
- if fs.opts.interop == InteropModeShared {
- if err := oldParent.updateFromGetattr(ctx); err != nil {
- return err
- }
- }
- if err := oldParent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec, true); err != nil {
- return err
- }
- vfsObj := rp.VirtualFilesystem()
- // We need a dentry representing the renamed file since, if it's a
- // directory, we need to check for write permission on it.
- oldParent.dirMu.Lock()
- defer oldParent.dirMu.Unlock()
- renamed, err := fs.revalidateChildLocked(ctx, vfsObj, oldParent, oldName, oldParent.vfsd.Child(oldName), &ds)
- if err != nil {
- return err
- }
- if renamed == nil {
- return syserror.ENOENT
- }
- if renamed.isDir() {
- if renamed == newParent || renamed.vfsd.IsAncestorOf(&newParent.vfsd) {
- return syserror.EINVAL
- }
- if oldParent != newParent {
- if err := renamed.checkPermissions(rp.Credentials(), vfs.MayWrite, true); err != nil {
- return err
- }
- }
- } else {
- if opts.MustBeDir || rp.MustBeDir() {
- return syserror.ENOTDIR
- }
- }
-
- if oldParent != newParent {
- if err := newParent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec, true); err != nil {
- return err
- }
- newParent.dirMu.Lock()
- defer newParent.dirMu.Unlock()
- }
- if newParent.isDeleted() {
- return syserror.ENOENT
- }
- replacedVFSD := newParent.vfsd.Child(newName)
- var replaced *dentry
- // This is similar to unlinkAt, except:
- //
- // - We revalidate the replaced dentry unconditionally for simplicity.
- //
- // - If rp.MustBeDir(), then we need a dentry representing the replaced
- // file regardless to confirm that it's a directory.
- if replacedVFSD != nil || rp.MustBeDir() {
- replaced, err = fs.revalidateChildLocked(ctx, vfsObj, newParent, newName, replacedVFSD, &ds)
- if err != nil {
- return err
- }
- if replaced != nil {
- if replaced.isDir() {
- if !renamed.isDir() {
- return syserror.EISDIR
- }
- } else {
- if rp.MustBeDir() || renamed.isDir() {
- return syserror.ENOTDIR
- }
- }
- replacedVFSD = &replaced.vfsd
- } else {
- replacedVFSD = nil
- }
- }
-
- if oldParent == newParent && oldName == newName {
- return nil
- }
- mntns := vfs.MountNamespaceFromContext(ctx)
- defer mntns.DecRef()
- if err := vfsObj.PrepareRenameDentry(mntns, &renamed.vfsd, replacedVFSD); err != nil {
- return err
- }
- if err := renamed.file.rename(ctx, newParent.file, newName); err != nil {
- vfsObj.AbortRenameDentry(&renamed.vfsd, replacedVFSD)
- return err
- }
- if fs.opts.interop != InteropModeShared {
- oldParent.cacheNegativeChildLocked(oldName)
- oldParent.dirents = nil
- delete(newParent.negativeChildren, newName)
- newParent.dirents = nil
- }
- vfsObj.CommitRenameReplaceDentry(&renamed.vfsd, &newParent.vfsd, newName, replacedVFSD)
- return nil
-}
-
-// RmdirAt implements vfs.FilesystemImpl.RmdirAt.
-func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error {
- return fs.unlinkAt(ctx, rp, true /* dir */)
-}
-
-// SetStatAt implements vfs.FilesystemImpl.SetStatAt.
-func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return err
- }
- return d.setStat(ctx, rp.Credentials(), &opts.Stat, rp.Mount())
-}
-
-// StatAt implements vfs.FilesystemImpl.StatAt.
-func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return linux.Statx{}, err
- }
- // Since walking updates metadata for all traversed dentries under
- // InteropModeShared, including the returned one, we can return cached
- // metadata here regardless of fs.opts.interop.
- var stat linux.Statx
- d.statTo(&stat)
- return stat, nil
-}
-
-// StatFSAt implements vfs.FilesystemImpl.StatFSAt.
-func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return linux.Statfs{}, err
- }
- fsstat, err := d.file.statFS(ctx)
- if err != nil {
- return linux.Statfs{}, err
- }
- nameLen := uint64(fsstat.NameLength)
- if nameLen > maxFilenameLen {
- nameLen = maxFilenameLen
- }
- return linux.Statfs{
- // This is primarily for distinguishing a gofer file system in
- // tests. Testing is important, so instead of defining
- // something completely random, use a standard value.
- Type: linux.V9FS_MAGIC,
- BlockSize: int64(fsstat.BlockSize),
- Blocks: fsstat.Blocks,
- BlocksFree: fsstat.BlocksFree,
- BlocksAvailable: fsstat.BlocksAvailable,
- Files: fsstat.Files,
- FilesFree: fsstat.FilesFree,
- NameLength: nameLen,
- }, nil
-}
-
-// SymlinkAt implements vfs.FilesystemImpl.SymlinkAt.
-func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, target string) error {
- return fs.doCreateAt(ctx, rp, false /* dir */, func(parent *dentry, name string) error {
- creds := rp.Credentials()
- _, err := parent.file.symlink(ctx, target, name, (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
- return err
- })
-}
-
-// UnlinkAt implements vfs.FilesystemImpl.UnlinkAt.
-func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error {
- return fs.unlinkAt(ctx, rp, false /* dir */)
-}
-
-// ListxattrAt implements vfs.FilesystemImpl.ListxattrAt.
-func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath) ([]string, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return nil, err
- }
- return d.listxattr(ctx)
-}
-
-// GetxattrAt implements vfs.FilesystemImpl.GetxattrAt.
-func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) (string, error) {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return "", err
- }
- return d.getxattr(ctx, name)
-}
-
-// SetxattrAt implements vfs.FilesystemImpl.SetxattrAt.
-func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return err
- }
- return d.setxattr(ctx, &opts)
-}
-
-// RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt.
-func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error {
- var ds *[]*dentry
- fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(&ds)
- d, err := fs.resolveLocked(ctx, rp, &ds)
- if err != nil {
- return err
- }
- return d.removexattr(ctx, name)
-}
-
-// PrependPath implements vfs.FilesystemImpl.PrependPath.
-func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDentry, b *fspath.Builder) error {
- fs.renameMu.RLock()
- defer fs.renameMu.RUnlock()
- return vfs.GenericPrependPath(vfsroot, vd, b)
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 12:16:48 +0000