> At 2:22 PM -0400 10/19/98, Chuck O'Donnell wrote:
> >Looking for the reason that htsearch exits with SIGSEGV when searching
> >for "(" on a boolean search instead of returning a "syntax error" or
> >"no match":
> >
> >Here's what I found using gdb:
> ...
> >Program received signal SIGSEGV, Segmentation fault.
> >Dictionary::Start_Get (this=0x0) at Dictionary.cc:319
> >319 currentTableIndex = -1;
> >(gdb) bt
> >#0 Dictionary::Start_Get (this=0x0) at Dictionary.cc:319
> >#1 0x3db2 in ResultList::elements (this=0x0) at ResultList.cc:105
> >#2 0x6c01 in Parser::parse (this=0x5b600, tokenList=0xefbfd85c,
> > resultMatches=@0x5f300) at parser.cc:387
> >#3 0x60ce in htsearch (wordfile=0x5f180
> >"/usr/local/htdig/db/db.words.db",
> > searchWords=@0xefbfd85c, parser=0x5b600) at htsearch.cc:606
> >#4 0x4f64 in main (ac=1, av=0xefbfd89c) at htsearch.cc:190
> >(gdb)
> >--
> >
> >Then trying to find out why "ResultList::elements (this=0x0)" is NULL,
> >we find in Parser::parse, line 387 of htsearch/parser.cc:
> ...
> >At line 386 and 387, "result" is not checked for NULL.
> >
> >From here, it would be helpful if someone more familiar with the
> >internals of htsearch could shed some light on a few things. I don't
> >know if the pointer returned from stack.pop() is not checked because
> >there should be pre-condition that the stack is never empty, or if
> >it's just that the check for NULL on the return value was overlooked.
> >And if the latter, what action is reasonable. Any thoughts?
>
> >From htlib/Stack.cc
> //***************************************************************************
> // Object *Stack::pop()
> // PURPOSE:
> // Return the object at the top of the stack and remove it from the stack.
> //
> Object *Stack::pop()
> {
> if (size == 0)
> return 0;
> ...
>
> So if the stack is empty, it returns NULL. So the check was overlooked. I'm
> not sure what a good error condition would be. I don't know where it was
> called in the first place.
>
> One option is to just return and have the calling function find that it
> didn't get any results. The other option is to return a value and have the
> calling function find the error through the returned value.
>
Here's something that looks interesting... look around line 428 of
htsearch.cc. The "reportError()" function has been commented out and
and empty list returned.
---cut----
//
// If the user specified boolean expression operators, the whole
// expression has to be syntactically correct. If not, we need
// to report a syntax error.
//
if (boolean)
{
if (!parser->checkSyntax(&tempWords))
{
for (i = 0; i < tempWords.Count(); i++)
{
searchWords.Add(tempWords[i]);
}
tempWords.Release();
return;
// reportError("Syntax error");
}
}
else
{
convertToBoolean(tempWords);
}
---cut----
I don't know if this is relevent or not, just interesting. I'll look
around a little more later.
Thanks.
Chuck
----------------------------------------------------------------------
To unsubscribe from the htdig mailing list, send a message to
[EMAIL PROTECTED] containing the single word "unsubscribe" in
the body of the message.
