[colm-users] Off by one error in pdarun.c

[Wictor Lund]

On Thu, Feb 28, 2019 at 06:28:54PM +0200, Adrian Thurston wrote:
> Hi Wictor,
> 
> Strings in colm are not normally null terminated. Probably the error you're
> seeing originates from when the string is printed. Can you share some code
> that exhibits the problem?
> 

Ok, I didn't know this. However, the string in question is being printed as
C string here:
         src/compiler.cc    void Compiler::parsePatterns()
 1014                 if ( pdaRun->parse_error_text != 0 ) {
 1015                         cerr << ": relative error: " << 
 1016                                         pdaRun->parse_error_text->tokdata->data;
 1017                 }
 1018                 else {
 1019                         cerr << ": parse error";
 1020                 }

--
Wictor Lund

> On 2019-02-27 14:58, Wictor Lund wrote:
> > diff --git a/src/pdarun.c b/src/pdarun.c
> > index ab0de7eb..3914bc65 100644
> > --- a/src/pdarun.c
> > +++ b/src/pdarun.c
> > @@ -436,9 +436,15 @@ static void report_parse_error( program_t *prg,
> > tree_t **sp, struct pda_run *pda
> > 
> > 
> >                 if ( name == 0 )
> >                         name = "<input>";
> > -               char *formatted = malloc( strlen( name ) + 128 );
> > -               sprintf( formatted, "%s:%ld:%ld: parse error", name,
> > line, column );
> > -               error_head = string_alloc_full( prg, formatted,
> > strlen(formatted) );
> > +               size_t formatted_s = strlen( name ) + 128;
> > +               char *formatted = malloc( formatted_s );
> > +               size_t fmt_s = snprintf( formatted, formatted_s,
> > +                                        "%s:%ld:%ld: parse error",
> > +                                        name, line, column );
> > +               if ( fmt_s >= formatted_s ) {
> > +                       fmt_s = formatted_s - 1;
> > +               }
> > +               error_head = string_alloc_full( prg, formatted, fmt_s +
> > 1 );
> >                 free( formatted );
> > 
> >                 error_head->location = location_allocate( prg );