Re: [Qemu-devel] [PATCH] chardev-socket: do not blindly reset handlers when switching GMainContext

[Marc-André Lureau]

Hi

On Wed, Feb 20, 2019 at 5:08 PM Paolo Bonzini <address@hidden> wrote:
>
> If the socket is connecting or connected, tcp_chr_update_read_handler will
> be called but it should not set the NetListener's callbacks again.
> Otherwise, tcp_chr_accept is invoked while the socket is in connected
> state and you get an assertion failure.
>
> Signed-off-by: Paolo Bonzini <address@hidden>

Change looks good,

> ---
>  chardev/char-socket.c |  2 +-
>  tests/test-char.c     | 95 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 96 insertions(+), 1 deletion(-)
>
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 4fcdd8a..6d287ba 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -632,7 +632,7 @@ static void tcp_chr_update_read_handler(Chardev *chr)
>  {
>      SocketChardev *s = SOCKET_CHARDEV(chr);
>
> -    if (s->listener) {
> +    if (s->listener && s->state == TCP_CHARDEV_STATE_DISCONNECTED) {
>          /*
>           * It's possible that chardev context is changed in
>           * qemu_chr_be_update_read_handlers().  Reset it for QIO net
> diff --git a/tests/test-char.c b/tests/test-char.c
> index 63b4d32..f1dec89 100644
> --- a/tests/test-char.c
> +++ b/tests/test-char.c
> @@ -1003,6 +1003,97 @@ static void char_socket_client_test(gconstpointer 
> opaque)
>      g_free(optstr);
>  }
>
> +static void
> +count_closed_event(void *opaque, int event)
> +{
> +    int *count = opaque;
> +    if (event == CHR_EVENT_CLOSED) {
> +        (*count)++;
> +    }
> +}
> +
> +
> +static void char_socket_server_two_clients_test(gconstpointer opaque)
> +{
> +    SocketAddress *incoming_addr = (gpointer) opaque;
> +    Chardev *chr;
> +    CharBackend be = {0};
> +    QObject *qaddr;
> +    SocketAddress *addr;
> +    Visitor *v;
> +    char *optstr;
> +    QemuOpts *opts;
> +    QIOChannelSocket *ioc1, *ioc2;
> +    int closed = 0;
> +
> +    g_setenv("QTEST_SILENT_ERRORS", "1", 1);
> +    /*
> +     * We rely on addr containing "nowait", otherwise
> +     * qemu_chr_new() will block until a client connects. We
> +     * can't spawn our client thread though, because until
> +     * qemu_chr_new() returns we don't know what TCP port was
> +     * allocated by the OS
> +     */
> +    optstr = char_socket_addr_to_opt_str(incoming_addr,
> +                                         false,
> +                                         NULL,
> +                                         true);
> +    opts = qemu_opts_parse_noisily(qemu_find_opts("chardev"),
> +                                   optstr, true);
> +    g_assert_nonnull(opts);
> +    chr = qemu_chr_new_from_opts(opts, NULL, &error_abort);
> +    qemu_opts_del(opts);
> +    g_assert_nonnull(chr);
> +    g_assert(!object_property_get_bool(OBJECT(chr), "connected", 
> &error_abort));
> +
> +    qaddr = object_property_get_qobject(OBJECT(chr), "addr", &error_abort);
> +    g_assert_nonnull(qaddr);
> +
> +    v = qobject_input_visitor_new(qaddr);
> +    visit_type_SocketAddress(v, "addr", &addr, &error_abort);
> +    visit_free(v);
> +    qobject_unref(qaddr);
> +
> +    qemu_chr_fe_init(&be, chr, &error_abort);
> +
> +    qemu_chr_fe_set_handlers(&be, NULL, NULL, count_closed_event, NULL,
> +                             &closed, NULL, true);
> +
> +    ioc1 = qio_channel_socket_new();
> +    qio_channel_socket_connect_sync(ioc1, addr, &error_abort);
> +    qemu_chr_wait_connected(chr, &error_abort);
> +
> +    /* switch the chardev to another context */
> +    GMainContext *ctx = g_main_context_new();
> +    qemu_chr_fe_set_handlers(&be, NULL, NULL, count_closed_event, NULL,
> +                             &closed, ctx, true);
> +
> +    /* Start a second connection while the first is still connected.
> +     * It will be placed in the listen() backlog, and connect() will
> +     * succeed immediately.
> +     */
> +    ioc2 = qio_channel_socket_new();
> +    qio_channel_socket_connect_sync(ioc2, addr, &error_abort);
> +
> +    object_unparent(OBJECT(ioc1));

But object_unparent() is incorrect here, QIOChannel isn't parented.
unref() instead.

> +    /* The two connections should now be processed serially.  */
> +    while (g_main_context_iteration(ctx, TRUE)) {
> +        if (closed == 1 && ioc2) {
> +            object_unparent(OBJECT(ioc2));
> +            ioc2 = NULL;
> +        }
> +        if (closed == 2) {
> +            break;
> +        }
> +    }
> +
> +    qapi_free_SocketAddress(addr);
> +    object_unparent(OBJECT(chr));
> +    g_main_context_unref(ctx);
> +    g_free(optstr);
> +    g_unsetenv("QTEST_SILENT_ERRORS");
> +}
> +
>
>  #ifdef HAVE_CHARDEV_SERIAL
>  static void char_serial_test(void)
> @@ -1346,6 +1437,10 @@ int main(int argc, char **argv)
>      SOCKET_SERVER_TEST(unix, &unixaddr);
>      SOCKET_CLIENT_TEST(unix, &unixaddr);
>  #endif
> +    g_test_add_data_func("/char/socket/server/two-clients/tcp", &tcpaddr,
> +                        char_socket_server_two_clients_test);
> +    g_test_add_data_func("/char/socket/server/two-clients/unix", &unixaddr,
> +                        char_socket_server_two_clients_test);

tabs

with that,
Reviewed-by: Marc-André Lureau <address@hidden>


>
>
>      g_test_add_func("/char/udp", char_udp_test);
> --
> 1.8.3.1
>
>


-- 
Marc-André Lureau