diff options
Diffstat (limited to 'pkg/sentry/fsimpl/gofer/directory.go')
-rw-r--r-- | pkg/sentry/fsimpl/gofer/directory.go | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/pkg/sentry/fsimpl/gofer/directory.go b/pkg/sentry/fsimpl/gofer/directory.go deleted file mode 100644 index 6d4ebc2bf..000000000 --- a/pkg/sentry/fsimpl/gofer/directory.go +++ /dev/null @@ -1,194 +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" - "sync/atomic" - - "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/p9" - "gvisor.dev/gvisor/pkg/sentry/vfs" - "gvisor.dev/gvisor/pkg/syserror" -) - -func (d *dentry) isDir() bool { - return d.fileType() == linux.S_IFDIR -} - -// Preconditions: d.dirMu must be locked. d.isDir(). fs.opts.interop != -// InteropModeShared. -func (d *dentry) cacheNegativeChildLocked(name string) { - if d.negativeChildren == nil { - d.negativeChildren = make(map[string]struct{}) - } - d.negativeChildren[name] = struct{}{} -} - -type directoryFD struct { - fileDescription - vfs.DirectoryFileDescriptionDefaultImpl - - mu sync.Mutex - off int64 - dirents []vfs.Dirent -} - -// Release implements vfs.FileDescriptionImpl.Release. -func (fd *directoryFD) Release() { -} - -// IterDirents implements vfs.FileDescriptionImpl.IterDirents. -func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback) error { - fd.mu.Lock() - defer fd.mu.Unlock() - - if fd.dirents == nil { - ds, err := fd.dentry().getDirents(ctx) - if err != nil { - return err - } - fd.dirents = ds - } - - for fd.off < int64(len(fd.dirents)) { - if !cb.Handle(fd.dirents[fd.off]) { - return nil - } - fd.off++ - } - return nil -} - -// Preconditions: d.isDir(). There exists at least one directoryFD representing d. -func (d *dentry) getDirents(ctx context.Context) ([]vfs.Dirent, error) { - // 9P2000.L's readdir does not specify behavior in the presence of - // concurrent mutation of an iterated directory, so implementations may - // duplicate or omit entries in this case, which violates POSIX semantics. - // Thus we read all directory entries while holding d.dirMu to exclude - // directory mutations. (Note that it is impossible for the client to - // exclude concurrent mutation from other remote filesystem users. Since - // there is no way to detect if the server has incorrectly omitted - // directory entries, we simply assume that the server is well-behaved - // under InteropModeShared.) This is inconsistent with Linux (which appears - // to assume that directory fids have the correct semantics, and translates - // struct file_operations::readdir calls directly to readdir RPCs), but is - // consistent with VFS1. - // - // NOTE(b/135560623): In particular, some gofer implementations may not - // retain state between calls to Readdir, so may not provide a coherent - // directory stream across in the presence of mutation. - - d.fs.renameMu.RLock() - defer d.fs.renameMu.RUnlock() - d.dirMu.Lock() - defer d.dirMu.Unlock() - if d.dirents != nil { - return d.dirents, nil - } - - // It's not clear if 9P2000.L's readdir is expected to return "." and "..", - // so we generate them here. - parent := d.vfsd.ParentOrSelf().Impl().(*dentry) - dirents := []vfs.Dirent{ - { - Name: ".", - Type: linux.DT_DIR, - Ino: d.ino, - NextOff: 1, - }, - { - Name: "..", - Type: uint8(atomic.LoadUint32(&parent.mode) >> 12), - Ino: parent.ino, - NextOff: 2, - }, - } - off := uint64(0) - const count = 64 * 1024 // for consistency with the vfs1 client - d.handleMu.RLock() - defer d.handleMu.RUnlock() - if !d.handleReadable { - // This should not be possible because a readable handle should have - // been opened when the calling directoryFD was opened. - panic("gofer.dentry.getDirents called without a readable handle") - } - for { - p9ds, err := d.handle.file.readdir(ctx, off, count) - if err != nil { - return nil, err - } - if len(p9ds) == 0 { - // Cache dirents for future directoryFDs if permitted. - if d.fs.opts.interop != InteropModeShared { - d.dirents = dirents - } - return dirents, nil - } - for _, p9d := range p9ds { - if p9d.Name == "." || p9d.Name == ".." { - continue - } - dirent := vfs.Dirent{ - Name: p9d.Name, - Ino: p9d.QID.Path, - NextOff: int64(len(dirents) + 1), - } - // p9 does not expose 9P2000.U's DMDEVICE, DMNAMEDPIPE, or - // DMSOCKET. - switch p9d.Type { - case p9.TypeSymlink: - dirent.Type = linux.DT_LNK - case p9.TypeDir: - dirent.Type = linux.DT_DIR - default: - dirent.Type = linux.DT_REG - } - dirents = append(dirents, dirent) - } - off = p9ds[len(p9ds)-1].Offset - } -} - -// Seek implements vfs.FileDescriptionImpl.Seek. -func (fd *directoryFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { - fd.mu.Lock() - defer fd.mu.Unlock() - - switch whence { - case linux.SEEK_SET: - if offset < 0 { - return 0, syserror.EINVAL - } - if offset == 0 { - // Ensure that the next call to fd.IterDirents() calls - // fd.dentry().getDirents(). - fd.dirents = nil - } - fd.off = offset - return fd.off, nil - case linux.SEEK_CUR: - offset += fd.off - if offset < 0 { - return 0, syserror.EINVAL - } - // Don't clear fd.dirents in this case, even if offset == 0. - fd.off = offset - return fd.off, nil - default: - return 0, syserror.EINVAL - } -} |