[PATCH] Fix re-entrancy issues in wl_display_iterate().

[andy.nichols at nokia.com]

Hi,

I ran into this same re-entrancy problem with when using qtwayland, and this patch does fix the issue.

~
Andy Nichols
________________________________________
From: wayland-devel-bounces+andy.nichols=nokia.com at lists.freedesktop.org [wayland-devel-bounces+andy.nichols=nokia.com at lists.freedesktop.org] on behalf of ext yan.wang at linux.intel.com [yan.wang at linux.intel.com]
Sent: Friday, April 13, 2012 10:08 AM
To: Hannu Lyytinen
Cc: Hannu Lyytinen; wayland-devel at lists.freedesktop.org
Subject: Re: [PATCH] Fix re-entrancy issues in wl_display_iterate().

> This fixes a possible re-entrancy issue in case of nested requests.
>
> ---
>  src/connection.c      |    8 +++++++-
>  src/wayland-client.c  |    6 ++++--
>  src/wayland-private.h |    1 +
>  3 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/src/connection.c b/src/connection.c
> index 2795481..c5c9c77 100644
> --- a/src/connection.c
> +++ b/src/connection.c
> @@ -259,6 +259,12 @@ decode_cmsg(struct wl_buffer *buffer, struct msghdr
> *msg)
>  }
>
>  int
> +wl_connection_data_length(struct wl_connection *connection)
> +{
> +     return connection->in.head - connection->in.tail;
> +}
> +
> +int
>  wl_connection_data(struct wl_connection *connection, uint32_t mask)
>  {
>       struct iovec iov[2];
> @@ -335,7 +341,7 @@ wl_connection_data(struct wl_connection *connection,
> uint32_t mask)
>               connection->in.head += len;
>       }
>
> -     return connection->in.head - connection->in.tail;
> +     return wl_connection_data_length(connection);
>  }
>
>  int
> diff --git a/src/wayland-client.c b/src/wayland-client.c
> index 9057b4f..0bf8c81 100644
> --- a/src/wayland-client.c
> +++ b/src/wayland-client.c
> @@ -509,9 +509,11 @@ wl_display_iterate(struct wl_display *display,
> uint32_t mask)
>               return;
>       }
>
> -     len = wl_connection_data(display->connection, mask);
> +     wl_connection_data(display->connection, mask);
> +
> +     for (;;) {
> +             len = wl_connection_data_length(display->connection);
>
> -     while (len > 0) {
>               if ((size_t) len < sizeof p)
>                       break;
>
> diff --git a/src/wayland-private.h b/src/wayland-private.h
> index b843e89..416f4af 100644
> --- a/src/wayland-private.h
> +++ b/src/wayland-private.h
> @@ -65,6 +65,7 @@ void wl_connection_destroy(struct wl_connection
> *connection);
>  void wl_connection_copy(struct wl_connection *connection, void *data,
> size_t size);
>  void wl_connection_consume(struct wl_connection *connection, size_t
> size);
>  int wl_connection_data(struct wl_connection *connection, uint32_t mask);
> +int wl_connection_data_length(struct wl_connection *connection);
>  int wl_connection_write(struct wl_connection *connection, const void
> *data, size_t count);
>  int wl_connection_queue(struct wl_connection *connection,
>                       const void *data, size_t count);
> --
> 1.7.1
>
> _______________________________________________
> wayland-devel mailing list
> wayland-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/wayland-devel
>
wl_display_iterate will be called in multiply threads? Normally, I think
it may be called in message loop thread.
Thanks.

Yan Wang
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