github.com/metacubex/gvisor@v0.0.0-20240320004321-933faba989ec/pkg/sentry/fsimpl/fuse/directory.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package fuse
    16  
    17  import (
    18  	"github.com/metacubex/gvisor/pkg/abi/linux"
    19  	"github.com/metacubex/gvisor/pkg/context"
    20  	"github.com/metacubex/gvisor/pkg/errors/linuxerr"
    21  	"github.com/metacubex/gvisor/pkg/sentry/kernel/auth"
    22  	"github.com/metacubex/gvisor/pkg/sentry/vfs"
    23  	"github.com/metacubex/gvisor/pkg/usermem"
    24  )
    25  
    26  // +stateify savable
    27  type directoryFD struct {
    28  	fileDescription
    29  }
    30  
    31  // Allocate implements directoryFD.Allocate.
    32  func (*directoryFD) Allocate(ctx context.Context, mode, offset, length uint64) error {
    33  	return linuxerr.EISDIR
    34  }
    35  
    36  // PRead implements vfs.FileDescriptionImpl.PRead.
    37  func (*directoryFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
    38  	return 0, linuxerr.EISDIR
    39  }
    40  
    41  // Read implements vfs.FileDescriptionImpl.Read.
    42  func (*directoryFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
    43  	return 0, linuxerr.EISDIR
    44  }
    45  
    46  // PWrite implements vfs.FileDescriptionImpl.PWrite.
    47  func (*directoryFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
    48  	return 0, linuxerr.EISDIR
    49  }
    50  
    51  // Write implements vfs.FileDescriptionImpl.Write.
    52  func (*directoryFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
    53  	return 0, linuxerr.EISDIR
    54  }
    55  
    56  // IterDirents implements vfs.FileDescriptionImpl.IterDirents.
    57  func (dir *directoryFD) IterDirents(ctx context.Context, callback vfs.IterDirentsCallback) error {
    58  	fusefs := dir.inode().fs
    59  
    60  	in := linux.FUSEReadIn{
    61  		Fh:     dir.Fh,
    62  		Offset: uint64(dir.off.Load()),
    63  		Size:   linux.FUSE_PAGE_SIZE,
    64  		Flags:  dir.statusFlags(),
    65  	}
    66  
    67  	// TODO(gVisor.dev/issue/3404): Support FUSE_READDIRPLUS.
    68  	req := fusefs.conn.NewRequest(auth.CredentialsFromContext(ctx), pidFromContext(ctx), dir.inode().nodeID, linux.FUSE_READDIR, &in)
    69  	res, err := fusefs.conn.Call(ctx, req)
    70  	if err != nil {
    71  		return err
    72  	}
    73  	if err := res.Error(); err != nil {
    74  		return err
    75  	}
    76  
    77  	var out linux.FUSEDirents
    78  	if err := res.UnmarshalPayload(&out); err != nil {
    79  		return err
    80  	}
    81  
    82  	for _, fuseDirent := range out.Dirents {
    83  		nextOff := int64(fuseDirent.Meta.Off)
    84  		dirent := vfs.Dirent{
    85  			Name:    fuseDirent.Name,
    86  			Type:    uint8(fuseDirent.Meta.Type),
    87  			Ino:     fuseDirent.Meta.Ino,
    88  			NextOff: nextOff,
    89  		}
    90  
    91  		if err := callback.Handle(dirent); err != nil {
    92  			return err
    93  		}
    94  		dir.off.Store(nextOff)
    95  	}
    96  
    97  	return nil
    98  }