From dced1d6a37293ce23ee2b07d3ebe81f25eced9ad Mon Sep 17 00:00:00 2001 From: Brad Fitzpatrick Date: Fri, 6 Nov 2020 12:56:24 -0800 Subject: [PATCH] ipn: treat zero-length file state store file as missing Signed-off-by: Brad Fitzpatrick (cherry picked from commit 8f30fa67aa4d86a1986ba0af70b4e2b00386b278) --- ipn/store.go | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/ipn/store.go b/ipn/store.go index d586f5729..117c68ca7 100644 --- a/ipn/store.go +++ b/ipn/store.go @@ -10,6 +10,7 @@ import ( "errors" "fmt" "io/ioutil" + "log" "os" "path/filepath" "sync" @@ -100,6 +101,14 @@ func (s *FileStore) String() string { return fmt.Sprintf("FileStore(%q)", s.path // NewFileStore returns a new file store that persists to path. func NewFileStore(path string) (*FileStore, error) { bs, err := ioutil.ReadFile(path) + + // Treat an empty file as a missing file. + // (https://github.com/tailscale/tailscale/issues/895#issuecomment-723255589) + if err == nil && len(bs) == 0 { + log.Printf("ipn.NewFileStore(%q): file empty; treating it like a missing file [warning]", path) + err = os.ErrNotExist + } + if err != nil { if os.IsNotExist(err) { // Write out an initial file, to verify that we can write