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authorRidwan Sharif <ridwanmsharif@google.com>2020-07-27 14:42:31 -0400
committerAndrei Vagin <avagin@gmail.com>2020-09-16 12:19:30 -0700
commit4a5857d644ae0e62090bbbed86852dceca79395c (patch)
treedb83d5ffdd979334781957050fbf6eb6d43a4741 /pkg/sentry/fsimpl
parentbc07df88878f47a496f8b364b286bf0b11c0e76f (diff)
fuse: Implement IterDirents for directory file description
Fixes #3255. This change adds support for IterDirents. You can now use `ls` in the FUSE sandbox. Co-authored-by: Craig Chi <craigchi@google.com>
Diffstat (limited to 'pkg/sentry/fsimpl')
-rw-r--r--pkg/sentry/fsimpl/fuse/connection.go8
-rw-r--r--pkg/sentry/fsimpl/fuse/directory.go54
-rw-r--r--pkg/sentry/fsimpl/fuse/file.go6
-rw-r--r--pkg/sentry/fsimpl/kernfs/kernfs.go2
4 files changed, 68 insertions, 2 deletions
diff --git a/pkg/sentry/fsimpl/fuse/connection.go b/pkg/sentry/fsimpl/fuse/connection.go
index 236165652..133306158 100644
--- a/pkg/sentry/fsimpl/fuse/connection.go
+++ b/pkg/sentry/fsimpl/fuse/connection.go
@@ -21,6 +21,8 @@ import (
"sync/atomic"
"syscall"
+ "gvisor.dev/gvisor/tools/go_marshal/marshal"
+
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/log"
@@ -352,6 +354,12 @@ func (r *Response) UnmarshalPayload(m marshal.Marshallable) error {
return fmt.Errorf("payload too small. Minimum data lenth required: %d, but got data length %d", wantDataLen, haveDataLen)
}
+ // The response data is empty unless there is some payload. And so, doesn't
+ // need to be unmarshalled.
+ if r.data == nil {
+ return nil
+ }
+
m.UnmarshalUnsafe(r.data[hdrLen:])
return nil
}
diff --git a/pkg/sentry/fsimpl/fuse/directory.go b/pkg/sentry/fsimpl/fuse/directory.go
index 44d41712a..8c59680e8 100644
--- a/pkg/sentry/fsimpl/fuse/directory.go
+++ b/pkg/sentry/fsimpl/fuse/directory.go
@@ -15,7 +15,12 @@
package fuse
import (
+ "sync/atomic"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserror"
"gvisor.dev/gvisor/pkg/usermem"
@@ -49,3 +54,52 @@ func (directoryFD) PWrite(ctx context.Context, src usermem.IOSequence, offset in
func (directoryFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
return 0, syserror.EISDIR
}
+
+// IterDirents implements FileDescriptionImpl.IterDirents.
+func (dir *directoryFD) IterDirents(ctx context.Context, callback vfs.IterDirentsCallback) error {
+ fusefs := dir.inode().fs
+ task, creds := kernel.TaskFromContext(ctx), auth.CredentialsFromContext(ctx)
+
+ in := linux.FUSEReadIn{
+ Fh: dir.Fh,
+ Offset: uint64(atomic.LoadInt64(&dir.off)),
+ Size: linux.FUSE_PAGE_SIZE,
+ Flags: dir.statusFlags(),
+ }
+
+ /// TODO(gVisor.dev/issue/3404): Support FUSE_READDIRPLUS.
+ req, err := fusefs.conn.NewRequest(creds, uint32(task.ThreadID()), dir.inode().NodeID, linux.FUSE_READDIR, &in)
+ if err != nil {
+ return err
+ }
+
+ res, err := fusefs.conn.Call(task, req)
+ if err != nil {
+ return err
+ }
+ if err := res.Error(); err != nil {
+ return err
+ }
+
+ var out linux.FUSEDirents
+ if err := res.UnmarshalPayload(&out); err != nil {
+ return err
+ }
+
+ for _, fuseDirent := range out.Dirents {
+ nextOff := int64(fuseDirent.Meta.Off) + 1
+ dirent := vfs.Dirent{
+ Name: fuseDirent.Name,
+ Type: uint8(fuseDirent.Meta.Type),
+ Ino: fuseDirent.Meta.Ino,
+ NextOff: nextOff,
+ }
+
+ if err := callback.Handle(dirent); err != nil {
+ return err
+ }
+ atomic.StoreInt64(&dir.off, nextOff)
+ }
+
+ return nil
+}
diff --git a/pkg/sentry/fsimpl/fuse/file.go b/pkg/sentry/fsimpl/fuse/file.go
index 01d20caf6..186ec2362 100644
--- a/pkg/sentry/fsimpl/fuse/file.go
+++ b/pkg/sentry/fsimpl/fuse/file.go
@@ -42,6 +42,9 @@ type fileDescription struct {
// OpenFlag is the flag returned by open.
OpenFlag uint32
+
+ // off is the file offset.
+ off int64
}
func (fd *fileDescription) dentry() *kernfs.Dentry {
@@ -119,5 +122,6 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu
// SetStat implements FileDescriptionImpl.SetStat.
func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
- return nil
+ creds := auth.CredentialsFromContext(ctx)
+ return fd.inode().SetStat(ctx, fd.inode().fs.VFSFilesystem(), creds, opts)
}
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index f656e2a8b..61189af25 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -425,7 +425,7 @@ type inodeDynamicLookup interface {
Valid(ctx context.Context) bool
// IterDirents is used to iterate over dynamically created entries. It invokes
- // cb on each entry in the directory represented by the FileDescription.
+ // cb on each entry in the directory represented by the Inode.
// 'offset' is the offset for the entire IterDirents call, which may include
// results from the caller (e.g. "." and ".."). 'relOffset' is the offset
// inside the entries returned by this IterDirents invocation. In other words,