From fbce7584d786ed99354a4b33a9c127abd673c3bb Mon Sep 17 00:00:00 2001 From: Paul Holzinger Date: Tue, 5 Oct 2021 11:13:49 +0200 Subject: libpod: fix race when closing STDIN There is a race where `conn.Close()` was called before `conn.CloseWrite()`. In this case `CloseWrite` will fail and an useless error is printed. To fix this we move the the `CloseWrite()` call to the same goroutine to remove the race. This ensures that `CloseWrite()` is called before `Close()` and never afterwards. Also fixed podman-remote run where the STDIN was never was closed. This is causing flakes in CI testing. [NO TESTS NEEDED] Fixes #11856 Signed-off-by: Paul Holzinger --- libpod/oci_attach_linux.go | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'libpod/oci_attach_linux.go') diff --git a/libpod/oci_attach_linux.go b/libpod/oci_attach_linux.go index d4d4a1076..1f2a28ead 100644 --- a/libpod/oci_attach_linux.go +++ b/libpod/oci_attach_linux.go @@ -93,7 +93,7 @@ func (c *Container) attach(streams *define.AttachStreams, keys string, resize <- if attachRdy != nil { attachRdy <- true } - return readStdio(streams, receiveStdoutError, stdinDone) + return readStdio(conn, streams, receiveStdoutError, stdinDone) } // Attach to the given container's exec session @@ -174,7 +174,7 @@ func (c *Container) attachToExec(streams *define.AttachStreams, keys *string, se return err } - return readStdio(streams, receiveStdoutError, stdinDone) + return readStdio(conn, streams, receiveStdoutError, stdinDone) } func processDetachKeys(keys string) ([]byte, error) { @@ -217,11 +217,6 @@ func setupStdioChannels(streams *define.AttachStreams, conn *net.UnixConn, detac var err error if streams.AttachInput { _, err = utils.CopyDetachable(conn, streams.InputStream, detachKeys) - if err == nil { - if connErr := conn.CloseWrite(); connErr != nil { - logrus.Errorf("Unable to close conn: %q", connErr) - } - } } stdinDone <- err }() @@ -274,7 +269,7 @@ func redirectResponseToOutputStreams(outputStream, errorStream io.Writer, writeO return err } -func readStdio(streams *define.AttachStreams, receiveStdoutError, stdinDone chan error) error { +func readStdio(conn *net.UnixConn, streams *define.AttachStreams, receiveStdoutError, stdinDone chan error) error { var err error select { case err = <-receiveStdoutError: @@ -283,6 +278,12 @@ func readStdio(streams *define.AttachStreams, receiveStdoutError, stdinDone chan if err == define.ErrDetach { return err } + if err == nil { + // copy stdin is done, close it + if connErr := conn.CloseWrite(); connErr != nil { + logrus.Errorf("Unable to close conn: %v", connErr) + } + } if streams.AttachOutput || streams.AttachError { return <-receiveStdoutError } -- cgit v1.2.3-54-g00ecf