On Fri, Nov 03, 2017 at 04:03:44PM +0800, Michael W. Bombardieri wrote:
> Hello,
>
> In yacc the dup_line() function malloc()'ed a buffer and copied
> a line into it. The copied line includes \n.
> Allocate-and-copy can be done by strndup() in one hit.
> I ran this on i386 with awk/awkgram.y and rcs/date.y and didn't
> see any difference in y.tab.c compared to the system's yacc.
>
> - Michael
Forgot to mention. The assert() is triggered if '\0' is encountered before '\n'.
Even if that is ok, a better error message could be printed instead of assert().
>
>
> Index: reader.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/yacc/reader.c,v
> retrieving revision 1.34
> diff -u -p -u -r1.34 reader.c
> --- reader.c 25 May 2017 20:11:03 -0000 1.34
> +++ reader.c 3 Nov 2017 07:48:08 -0000
> @@ -171,21 +171,17 @@ get_line(void)
> char *
> dup_line(void)
> {
> - char *p, *s, *t;
> + char *p, *end;
> + size_t len;
>
> if (line == NULL)
> - return (0);
> - s = line;
> - while (*s != '\n')
> - ++s;
> - p = malloc(s - line + 1);
> + return (NULL);
> + end = strchr(line, '\n');
> + assert(end != NULL);
> + len = end - line + 1;
> + p = strndup(line, len);
> if (p == NULL)
> no_space();
> -
> - s = line;
> - t = p;
> - while ((*t++ = *s++) != '\n')
> - continue;
> return (p);
> }
>
