[RFA2] Follow-up decode_line_1 crash

Fernando Nasser fnasser@redhat.com
Wed Mar 14 09:48:00 GMT 2001


I have tried it and it looks OK (on Red Hat 7.0).

Let's try it.

Fernando


Keith Seitz wrote:
> 
> Problem:
> 
> $ gdb -nw -nx -q
> (gdb) b "foo"
> Segmentation fault (core dumped)
> 
> decode_linespec_1 does something like:
> 
> char *p = *argptr; (the first quote in "foo")
> if (p == '"')
>   {
>     p++;
>     is_quote_enclosed = 1;
>   }
> 
>   if (is_quote_enclosed)
>     {
>       char *closing_quote = strchr (p, '"');
>       if (closing_quote && closing_quote[1] == '\0')
>         *closing_quote = '\0';
>     }
> 
> /* so now p looks like foo with no quotes and *argptr is "foo */
> 
> char *copy = (char *) alloca (p - *argptr + 1); <-- alloca of 0 bytes
> memcpy (copy, *argptr, p - *argptr); <-- copy -1 bytes
> 
> Patch:
> 
> Index: linespec.c
> ===================================================================
> RCS file: /cvs/cvsfiles/devo/gdb/linespec.c,v
> retrieving revision 2.4
> diff -p -p -r2.4 linespec.c
> *** linespec.c  2000/12/20 14:34:15     2.4
> --- linespec.c  2001/03/14 16:16:11
> *************** decode_line_1 (char **argptr, int funfir
> *** 611,620 ****
> 
>     s = NULL;
>     p = *argptr;
> !   if (p[0] == '"')
>       {
>         is_quote_enclosed = 1;
> !       p++;
>       }
>     else
>       is_quote_enclosed = 0;
> --- 611,620 ----
> 
>     s = NULL;
>     p = *argptr;
> !   if (**argptr == '"')
>       {
>         is_quote_enclosed = 1;
> !       (*argptr)++;
>       }
>     else
>       is_quote_enclosed = 0;
> 
> Tested on RH6.2. Should be generic enough to apply to all targets. I'm no
> expert at this stuff, but a crash is Just Plain Bad (TM).
> 
> Keith

-- 
Fernando Nasser
Red Hat Canada Ltd.                     E-Mail:  fnasser@redhat.com
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9



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