RE: ost::String class release 1.1.1

[erik_ohrnberger]

i686 AMD Athlon(tm) Processor AuthenticAMD GNU/Linux

> -----Original Message-----
> From: David Sugar [mailto:address@hidden
> Sent: Monday, April 05, 2004 2:10 AM
> To: Ohrnberger, Erik; address@hidden
> Subject: Re: ost::String class release 1.1.1
> 
> 
> The idx[slot] list is a link list sorted by size.  The place 
> to start is first 
> to confirm if the slot[idx] is being correctly initialized to 
> NULL, and, in 
> the separate place where strings are being deleted, if they 
> are being added 
> to the linked list correctly.  This may also be an alignment 
> issue, depending 
> on the architecture.  What cpu architecture is this being built on?
> 
> On Monday 05 April 2004 01:48 pm, address@hidden wrote:
> > David,
> >  635 char *String::getSpace(unsigned size)
> >  636 {
> >  637     unsigned        slot;
> >  638     char*           text = NULL;
> >  639     char**          next;
> >  640
> >  641     if(size > slotlimit)
> >  642         return new char[size];
> >  643
> >  644     slot = size / slotsize;
> >  645     mutex.enterMutex();
> >  646     if(!pager)
> >  647     {
> >  648         pager = new MemPager(pagesize);
> >  649         idx = (char **)pager->alloc(sizeof(char *) * slots);
> >  650         memset(idx, 0, sizeof(char *) * slots);
> >  651     }
> >  652     text = idx[slot];
> >  653     if(text)
> >  654     {
> >  655         next = (char **)text;
> >  656         idx[slot] = *next;
> >  657     }
> >  658     else
> >  659         text = (char *)pager->alloc(++slot * slotsize);
> >  660     mutex.leaveMutex();
> >  661     return text;
> >  662 }
> >
> > Right on line 656.
> > slot = 1
> > text = 0x32353964 <Address 0x32353964 out of bounds>
> > size = 1076041732
> >
> > I think that size must be way off (duh).  OK, so where'd 
> that come from?
> >
> >  407 void String::copy(const String &original)
> >  408 {
> >  409     char *ptr;
> >  410     content = original.content;
> >  411
> >  412     if(!isBig())
> >  413         return;
> >  414
> >  415     if(getLength() < minsize)
> >  416     {
> >  417         content.ministring.length = getLength();
> >  418         memcpy(content.ministring.text, getText(), 
> getLength() + 1);
> >  419         content.ministring.big = false;
> >  420         return;
> >  421     }
> >  422
> >  423     ptr = getText();
> >  424     content.bigstring.size = 
> setSize(content.bigstring.length + 1);
> >  425     content.bigstring.text = getSpace(getSize());
> >  426     memcpy(content.bigstring.text, ptr, getLength() + 1);
> >  427 }
> >
> > at line 425
> > getLength() = 8
> > ptr is pointing to a valid string of text.
> > content.bigstring.size = 32
> >
> > Hmm.  Hope that this helps, I'm afraid that I've not 
> studied this String
> > class sufficiently to diagnose this at the moment.  Perhaps 
> you'l ahve some
> > insights?
> >
> >     Thanks,
> >             Erik.
> >
> > > -----Original Message-----
> > > From: David Sugar [mailto:address@hidden
> > > Sent: Monday, April 05, 2004 1:27 AM
> > > To: Ohrnberger, Erik; address@hidden
> > > Subject: Re: ost::String class release 1.1.1
> > >
> > >
> > > Hmm...
> > >
> > > text is either assigned from a slot list (linked list) or
> > > from mempager
> > > alloc'd memory.  If the linked list is messed up, that is one
> > > possibility.
> > > However, the other option is if the string is too large, a
> > > simple new is
> > > used, and text is never modified.  Text is not initialized
> > > because it does
> > > not need a value until it needs to be assigned from the 
> list or from
> > > mempager.  Hence, it would help to know more about where
> > > precisely this
> > > segfault occurs.  One thing you can do is initially set text
> > > to NULL at the
> > > start of getSpace, as that would make it easier to determine
> > > what the real
> > > state of text is at the time it happens; whether its before
> > > or after it has
> > > been assigned by something.
> > >
> > > On Monday 05 April 2004 12:15 pm, address@hidden wrote:
> > > > Everyone,
> > > >         I'm noticing instances of seg faults in the
> > >
> > > ost::String::getSpace()
> > >
> > > > method, where the *text variable is assigned what appears
> > >
> > > to be random
> > >
> > > > garbage, and is yet used as a pointer into some data structure.
> > > >
> > > >         Has anyone else experienced a similar failure?
> > > >
> > > >         Is there a patch to the ost::String class that needs to
> > >
> > > be applied?
> > >
> > > >         Thanks,
> > > >                 Erik.
> > > >
> > > >
> > > > _______________________________________________
> > > > Bug-commoncpp mailing list
> > > > address@hidden
> > > > http://mail.gnu.org/mailman/listinfo/bug-commoncpp
> >
> > _______________________________________________
> > Bug-commoncpp mailing list
> > address@hidden
> > http://mail.gnu.org/mailman/listinfo/bug-commoncpp
> 
>