Bug in net module ?

[erny hombre]

Hello,

I have studied the code in elua_uip.c and I wonder why the following
code works:

elua_net_size elua_net_recvbuf( int s, luaL_Buffer* buf, elua_net_size
maxsize, s16 readto, unsigned timer_id, u32 to_us )
{
  return elua_net_recv_internal( s, buf, maxsize, readto, timer_id,
to_us, 1 );
}

The parameter buf is a pointer to luaL_Buffer and this pointer is passed
to the function elua_net_recv_internal. elua_net_recv_internal
interprets buf as a pointer to a buffer where the received characters
are stored into. So the first received character overwrites the first
byte in luaL_Buffer, but luaL_Buffer does not start with a buffer but
with other data elements:
typedef struct luaL_Buffer {
  char *p;            /* current position in buffer */
  int lvl;  /* number of strings in the stack (level) */
  lua_State *L;
  char buffer[LUAL_BUFFERSIZE];
} luaL_Buffer;

I think the correct call should be:

elua_net_size elua_net_recvbuf( int s, luaL_Buffer* buf, elua_net_size
maxsize, s16 readto, unsigned timer_id, u32 to_us )
{
  return elua_net_recv_internal( s, buf->buffer, maxsize, readto,
timer_id, to_us, 1 );
}

Erwin

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[erny hombre]

Hello,

Problem solved, I have overlooked the last parameter with_buffer of
elua_net_recv_internal. When set to 1, then the buffer is treated as
luaL_Buffer in the uip-application. Sorry for inconvenience.

Erwin

> Hello,
>
> I have studied the code in elua_uip.c and I wonder why the following
> code works:
>
> elua_net_size elua_net_recvbuf( int s, luaL_Buffer* buf, elua_net_size
> maxsize, s16 readto, unsigned timer_id, u32 to_us )
> {
>   return elua_net_recv_internal( s, buf, maxsize, readto, timer_id,
> to_us, 1 );
> }
>
> The parameter buf is a pointer to luaL_Buffer and this pointer is passed
> to the function elua_net_recv_internal. elua_net_recv_internal
> interprets buf as a pointer to a buffer where the received characters
> are stored into. So the first received character overwrites the first
> byte in luaL_Buffer, but luaL_Buffer does not start with a buffer but
> with other data elements:
> typedef struct luaL_Buffer {
>   char *p;            /* current position in buffer */
>   int lvl;  /* number of strings in the stack (level) */
>   lua_State *L;
>   char buffer[LUAL_BUFFERSIZE];
> } luaL_Buffer;
>
> I think the correct call should be:
>
> elua_net_size elua_net_recvbuf( int s, luaL_Buffer* buf, elua_net_size
> maxsize, s16 readto, unsigned timer_id, u32 to_us )
> {
>   return elua_net_recv_internal( s, buf->buffer, maxsize, readto,
> timer_id, to_us, 1 );
> }
>
> Erwin
>
> _______________________________________________
> Elua-dev mailing list
> [hidden email]
> https://lists.berlios.de/mailman/listinfo/elua-dev
>
>  

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[BogdanM]

I'm glad you figured it out, as I didn't have time to check that part of the source code, and I was starting to think that we do have a bug there :)

Best,
Bogdan

On Wed, Dec 2, 2009 at 10:28 PM, erny hombre <[hidden email]> wrote:

Hello,

Problem solved, I have overlooked the last parameter with_buffer of
elua_net_recv_internal. When set to 1, then the buffer is treated as
luaL_Buffer in the uip-application. Sorry for inconvenience.

Erwin

> Hello,
>
> I have studied the code in elua_uip.c and I wonder why the following
> code works:
>
> elua_net_size elua_net_recvbuf( int s, luaL_Buffer* buf, elua_net_size
> maxsize, s16 readto, unsigned timer_id, u32 to_us )
> {
>   return elua_net_recv_internal( s, buf, maxsize, readto, timer_id,
> to_us, 1 );
> }
>
> The parameter buf is a pointer to luaL_Buffer and this pointer is passed
> to the function elua_net_recv_internal. elua_net_recv_internal
> interprets buf as a pointer to a buffer where the received characters
> are stored into. So the first received character overwrites the first
> byte in luaL_Buffer, but luaL_Buffer does not start with a buffer but
> with other data elements:
> typedef struct luaL_Buffer {
>   char *p;            /* current position in buffer */
>   int lvl;  /* number of strings in the stack (level) */
>   lua_State *L;
>   char buffer[LUAL_BUFFERSIZE];
> } luaL_Buffer;
>
> I think the correct call should be:
>
> elua_net_size elua_net_recvbuf( int s, luaL_Buffer* buf, elua_net_size
> maxsize, s16 readto, unsigned timer_id, u32 to_us )
> {
>   return elua_net_recv_internal( s, buf->buffer, maxsize, readto,
> timer_id, to_us, 1 );
> }
>
> Erwin
>
> _______________________________________________
> Elua-dev mailing list
> [hidden email]
> https://lists.berlios.de/mailman/listinfo/elua-dev
>
>

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