[vlc-devel] Re: timeout on input (select(), read(), poll() timeout?)

[Georgi Chorbadzhiyski]

Rémi Denis-Courmont wrote:
> Le mardi 24 octobre 2006 22:54, Georgi Chorbadzhiyski a écrit :
>> > The problem is that when network connectivity dies, the connection
>> > is not timing out and VLC is not trying to reconnect. It just sits
>> > there awaiting frames.
>> >
>> > This option is not working for me.
>> >
>> >       --ipv4-timeout <integer>   TCP connection timeout
>> >           Default TCP connection timeout (in
>> >           milliseconds).
> 
> I think that's the timeout for the three-way handshaked, not for the 
> established connections. In factn the name is very unfortunate, since 
> it's not IPv4-specific, but TCP-specific.
> 
>> I've tried to find how to set timeout for select and/or socket read
>> functions. I see that parameter exists but I can't find where the
>> functions are called and if timeout parameter is exposed as command
>> line option somewhere.
> 
> net_ReadNonBlock (and net_Select, but I dislike it) have a timeout 
> parameter that is set by the calling plugin, at its discretion.

Yes, I've found the code. The problem is that net_Read is used in net_Gets
and net_Gets is used in number of places, see:

modules/access/mms/mmsh.c:412:    if( ( psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, NULL ) ) == NULL )
modules/access/mms/mmsh.c:435:        char *psz = net_Gets( p_access, p_sys->fd, NULL );
modules/access/mms/mmsh.c:645:    if( ( psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, NULL ) ) == NULL )
modules/access/mms/mmsh.c:662:        char *psz = net_Gets( p_access, p_sys->fd, NULL );
modules/access/rtsp/access.c:123:    char *psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, 0 );
modules/access/ftp.c:617:    psz_line = net_Gets( p_access, p_sys->fd_cmd, NULL );
modules/access/ftp.c:637:            char *psz_tmp = net_Gets( p_access, p_sys->fd_cmd, NULL );
modules/access/http.c:484:            char *psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, p_sys->p_vs );
modules/access/http.c:551:                char *psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, p_sys->p_vs );
modules/access/http.c:818:            psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, NULL );
modules/access/http.c:838:                psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, NULL );
modules/access/http.c:981:    if( ( psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, pvs ) ) == NULL )
modules/access/http.c:1029:        char *psz = net_Gets( VLC_OBJECT(p_access), p_sys->fd, pvs );

It seems that every usage of net_Read (and net_Gets FWIW) is error probably
leading to vlc hanging out and waiting forever for input if network connectivity
is lost.

Proposed ugly patch /15 seconds of course should not be hard coded but it is
reasonable default/.

--- io.c        2006-10-26 20:54:07.000000000 +0300
+++ io-patch.c  2006-10-26 20:54:35.000000000 +0300
@@ -421,7 +421,7 @@ char *__net_Gets( vlc_object_t *p_this,
             ptr = psz_line + i_line;
         }

-        if( net_Read( p_this, fd, p_vs, (uint8_t *)ptr, 1, VLC_TRUE ) != 1 )
+        if( net_ReadNonBlock( p_this, fd, p_vs, (uint8_t *)ptr, 1, 15 * 1000 ) != 1 )
         {
             if( i_line == 0 )
             {


May be these uses of net_Read should also be converted to net_ReadNonBlock.

modules/access/mms/mmsh.c:715:    if( net_Read( p_access, p_sys->fd, NULL, p_sys->buffer, 4, VLC_TRUE ) < 4 )
modules/access/mms/mmsh.c:727:    if( net_Read( p_access, p_sys->fd, NULL, p_sys->buffer + 4, restsize, VLC_TRUE ) < restsize )
modules/access/mms/mmsh.c:770:        (net_Read( p_access, p_sys->fd, NULL, &p_sys->buffer[12],
modules/access/rtsp/access.c:115:    return net_Read( p_access, p_sys->fd, 0, p_buffer, i_buffer, VLC_TRUE );
modules/access/ftp.c:478:    i_read = net_Read( p_access, p_sys->fd_data, NULL, p_buffer, i_len,
modules/access/tcp.c:144:    i_read = net_Read( p_access, p_sys->fd, NULL, p_buffer, i_len,
modules/access/udp.c:299:    p_block->i_buffer = net_Read( p_access, p_sys->fd, NULL,
modules/access/http.c:539:    i_read = net_Read( p_access, p_sys->fd, p_sys->p_vs, p_buffer, i_len, VLC_FALSE );
modules/access/http.c:607:    i_read = net_Read( p_access, p_sys->fd, p_sys->p_vs, &buffer, 1,
modules/access/http.c:618:    if( net_Read( p_access, p_sys->fd, p_sys->p_vs,
src/network/tcp.c:482:    if( net_Read( p_obj, fd, NULL, buffer, 2, VLC_TRUE ) != 2 )
src/network/tcp.c:509:        if( net_Read( p_obj, fd, NULL, buffer, 2, VLC_TRUE ) != 2 )
src/network/tcp.c:577:        if( net_Read( p_obj, fd, NULL, buffer, 8, VLC_TRUE ) != 8 )
src/network/tcp.c:607:        if( net_Read( p_obj, fd, NULL, buffer, 5, VLC_TRUE ) != 5 )
src/network/tcp.c:629:        if( net_Read( p_obj, fd, NULL, buffer, i_len, VLC_TRUE ) != i_len )

-- 
Georgi Chorbadzhiyski
http://georgi.unixsol.org/

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