[AGENT++] Small bug

[Jochen Katz]

Hi,

someone reported this a week ago and after some mails I think, this
function will be changed to:

int Vb::get_value(unsigned char *ptr, unsigned long &len,
                  const unsigned long maxlen,
                  const bool add_null_byte = false) const

So current code will not get a null byte, as the documentation of this
function always said.
If add_null_byte == true, a null byte will always be added and possibly
truncate the string if the buffer isn't big enough.

Any more comments or suggestions?

Don't expect a reply from me during the next two weeks, as I will be
here: http://en.wikipedia.org/wiki/Fuerteventura

Regards,
  Jochen


Karl Abicht wrote:
> Hi,
> 
> your code (vb.cpp):
> 
> // get an unsigned char array
> // caller specifies max len of target space
> int Vb::get_value(unsigned char *ptr, unsigned long &len,
> 		  const unsigned long maxlen) const
> {
>   if (iv_vb_value &&
>       iv_vb_value->valid() &&
>       (iv_vb_value->get_syntax() == sNMP_SYNTAX_OCTETS))
>   {
>     OctetStr *p_os = (OctetStr *)iv_vb_value;
>     len = p_os->len();
>     if (len > maxlen) len = maxlen;
>     memcpy(ptr, p_os->data(), len);
>     ptr[len] = 0;
>     return SNMP_CLASS_SUCCESS;
>   }
> 
>   ptr[0] = 0;
>   len = 0;
>   return SNMP_CLASS_INVALID;
> }
> 
> 
> The line ptr[len] sometimes writes behind the allowed maxlen.
> 
> len <  maxlen ==> ok
> len == maxlen ==> trouble 
> len >  maxlen ==> trouble
> 
> 
> Regards
> 
> Karl
>