From ca4ecf481d617edfae22a5735a657d60186392e1 Mon Sep 17 00:00:00 2001 From: Jamie Liu Date: Fri, 18 Sep 2020 13:23:41 -0700 Subject: Use a tmpfs file for shared anonymous and /dev/zero mmap on VFS2. This is more consistent with Linux (see comment on MM.NewSharedAnonMappable()). We don't do the same thing on VFS1 for reasons documented by the updated comment. PiperOrigin-RevId: 332514849 --- pkg/sentry/fsimpl/tmpfs/tmpfs.go | 31 ------------------------------- 1 file changed, 31 deletions(-) (limited to 'pkg/sentry/fsimpl/tmpfs/tmpfs.go') diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go index 4871e55d3..4658e1533 100644 --- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go +++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go @@ -746,37 +746,6 @@ func (fd *fileDescription) RemoveXattr(ctx context.Context, name string) error { return nil } -// NewMemfd creates a new tmpfs regular file and file description that can back -// an anonymous fd created by memfd_create. -func NewMemfd(ctx context.Context, creds *auth.Credentials, mount *vfs.Mount, allowSeals bool, name string) (*vfs.FileDescription, error) { - fs, ok := mount.Filesystem().Impl().(*filesystem) - if !ok { - panic("NewMemfd() called with non-tmpfs mount") - } - - // Per Linux, mm/shmem.c:__shmem_file_setup(), memfd inodes are set up with - // S_IRWXUGO. - inode := fs.newRegularFile(creds.EffectiveKUID, creds.EffectiveKGID, 0777) - rf := inode.impl.(*regularFile) - if allowSeals { - rf.seals = 0 - } - - d := fs.newDentry(inode) - defer d.DecRef(ctx) - d.name = name - - // Per Linux, mm/shmem.c:__shmem_file_setup(), memfd files are set up with - // FMODE_READ | FMODE_WRITE. - var fd regularFileFD - fd.Init(&inode.locks) - flags := uint32(linux.O_RDWR) - if err := fd.vfsfd.Init(&fd, flags, mount, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil { - return nil, err - } - return &fd.vfsfd, nil -} - // LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. func (fd *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) -- cgit v1.2.3