[FFmpeg-devel] [PATCH] libavformat/UDP Protocol : seg fault on closing

[Michael Niedermayer]

On Fri, Jan 13, 2012 at 07:15:46PM +0100, Laurent BRULET wrote:
> Hi ,
> 
> The following patch fixes ticket #915 (
> https://ffmpeg.org/trac/ffmpeg/ticket/915)
> 
> --
> Laurent
> 
> ---
> diff --git a/libavformat/udp.c b/libavformat/udp.c
> index cdcd136..c823b69 100644
> --- a/libavformat/udp.c
> +++ b/libavformat/udp.c
> @@ -71,6 +71,7 @@ typedef struct {
>      pthread_t circular_buffer_thread;
>      pthread_mutex_t mutex;
>      pthread_cond_t cond;

> +    int exit_thread;

this probably needs volatile


>  #endif
>      uint8_t tmp[UDP_MAX_PKT_SIZE+4];
>      int remaining_in_dg;
> @@ -327,7 +328,7 @@ static void *circular_buffer_task( void *_URLContext)
>      fd_set rfds;
>      struct timeval tv;
>  
> -    for(;;) {
> +    while(!s->exit_thread) {
>          int left;
>          int ret;
>          int len;

> @@ -529,6 +530,7 @@ static int udp_open(URLContext *h, const char *uri,
> int flags)

it seems the patch was linewraped



>          s->fifo = av_fifo_alloc(s->circular_buffer_size);
>          pthread_mutex_init(&s->mutex, NULL);
>          pthread_cond_init(&s->cond, NULL);
> +        s->exit_thread = 0;
>          if (pthread_create(&s->circular_buffer_thread, NULL,

should not be needed

                              > circular_buffer_task, h)) {
>              av_log(h, AV_LOG_ERROR, "pthread_create failed\n");
>              goto fail;
> @@ -617,12 +619,18 @@ static int udp_write(URLContext *h, const uint8_t
> *buf, int size)
>  static int udp_close(URLContext *h)
>  {
>      UDPContext *s = h->priv_data;
> +    int ret;
>  
>      if (s->is_multicast && (h->flags & AVIO_FLAG_READ))
>          udp_leave_multicast_group(s->udp_fd, (struct sockaddr
> *)&s->dest_addr);
>      closesocket(s->udp_fd);
>      av_fifo_free(s->fifo);
>  #if HAVE_PTHREADS
> +    s->exit_thread = 1;

> +    ret = pthread_join(s->circular_buffer_thread, NULL);

Is this safe in case the thread has not been started at all?

Thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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