I was able to find the location which causes the crash but i am not sure
how to fix it
In function Ns_VALog i call vsnprintf directly, it works, when it is
called via Ns_DStringVPintf it crashes. using va_copy does not help
{
char buf[4096];
vsnprintf(buf, sizeof(buf), fmt, *vaPtr);
Ns_DStringAppend(&cachePtr->buffer, buf);
}
//Ns_DStringVPrintf(&cachePtr->buffer, fmt, *vaPtr);
Gustaf Neumann wrote:
> there is nothing wrong on using *va_list in general.
> the problem is rather in vsnprintf, which does most probably
> a loop like in Ns_DStringVarAppend
>
> char *
> Ns_DStringVarAppend(Ns_DString *dsPtr, ...)
> {
> register char *s;
> va_list ap;
>
> va_start(ap, dsPtr);
> while ((s = va_arg(ap, char *)) != NULL) {
> Ns_DStringAppend(dsPtr, s);
> }
> va_end(ap);
>
> return dsPtr->string;
> }
>
> which fails, when the va_list is terminated by 0 and not (char*)NULL.
> however, this should not account for the problem with vsnprintf(),
> which should not read more arguments as indicated by the fmt string.
> You are the, the number of %-codes corresponds to the arguments?
> Is the error produced via Ns_TclLogErrorInfo() ?
>
> What happens, if you add at the end of the vararglist in the call
> causing the problem a (char*)NULL)?
>
> -gustaf neumann
>
>
>
> Vlad Seryakov schrieb:
>> I use ns_log or Ns_Log, so it should take care about it, it ends up in
>> Ns_DStringPrintf which calls vsnprintf.
>>
>>
>> Is it correct in x64 to pass *va_list?
>>
>> Ns_VALog(Ns_LogSeverity severity, CONST char *fmt, va_list *vaPtr)
>>
>> Gustaf Neumann wrote:
>>
>>> be sure to terminate va_* argument lists with NULL (or to be on the safe
>>> side
>>> with (char*)NULL) and not with 0. when you have sizeof(int) !=
>>> sizeof(char *),
>>> the compiler will put a 32bit for 0, a comparison with a 64bit null
>>> pointer
>>> will fail. I am pretty sure, the vsnprintf() tries to write an error
>>> message....
>>> and misses the end of the var arg list....
>>>
>>> -gustaf neumann
>>>
>>> PS: fixed a similar issue in xotcl more than a year ago.
>>>
>>> Vlad Seryakov schrieb:
>>>
>>>> Hi,
>>>>
>>>> This is an example when it crashes inside vsnprintf, experimenting i
>>>> found that issuing long unknown command crashes as well. In my case i
>>>> noticed that trying to log long lines does not work as well. In x32
>>>> everything works fine
>>>>
>>>> db:vlad[18:01:19]#uname -a
>>>> Linux db 2.6.22-ARCH #1 SMP PREEMPT Thu Oct 4 11:47:51 EDT 2007 x86_64
>>>> Intel(R) Xeon(R) CPU X5355 @ 2.66GHz GenuineIntel GNU/Linux
>>>>
>>>>
>>>> ossweb:nscp 1>
>>>> ossweb:nscp 1> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
>>>>
>>>>
>
>
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--
Vlad Seryakov
[EMAIL PROTECTED]
http://www.crystalballinc.com/vlad/
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