From ab6774cebf5c618d0cae579e84bd39666857f78b Mon Sep 17 00:00:00 2001 From: Andrei Vagin Date: Fri, 21 Jun 2019 17:24:11 -0700 Subject: [PATCH] gvisor/fs: getdents returns 0 if offset is equal to FileMaxOffset FileMaxOffset is a special case when lseek(d, 0, SEEK_END) has been called. PiperOrigin-RevId: 254498777 --- pkg/sentry/fs/dirent.go | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go index ca417d2bc..3cba259d9 100644 --- a/pkg/sentry/fs/dirent.go +++ b/pkg/sentry/fs/dirent.go @@ -948,9 +948,6 @@ func direntReaddir(ctx context.Context, d *Dirent, it DirIterator, root *Dirent, if dirCtx.Serializer == nil { panic("Dirent.Readdir: serializer must not be nil") } - if d.frozen { - return d.readdirFrozen(root, offset, dirCtx) - } // Check that this is actually a directory before emitting anything. // Once we have written entries for "." and "..", future errors from @@ -959,6 +956,16 @@ func direntReaddir(ctx context.Context, d *Dirent, it DirIterator, root *Dirent, return 0, syserror.ENOTDIR } + // This is a special case for lseek(fd, 0, SEEK_END). + // See SeekWithDirCursor for more details. + if offset == FileMaxOffset { + return offset, nil + } + + if d.frozen { + return d.readdirFrozen(root, offset, dirCtx) + } + // Collect attrs for "." and "..". dot, dotdot := d.GetDotAttrs(root)