[4494] in Athena Bugs
patch from the net to m4
daemon@ATHENA.MIT.EDU (Jonathan I. Kamens)
Sun Mar 11 19:01:15 1990
Date: Sun, 11 Mar 90 19:01:03 -0500
From: Jonathan I. Kamens <jik@pit-manager.MIT.EDU>
To: bugs@ATHENA.MIT.EDU
In article <5753@videovax.tv.tek.com>, bart@videovax.tv.tek.com (Bart
Massey) writes:
> m4 mysteriously started dumping core on me today, and after a couple hours
> of flailing, I figured out that it doesn't check for overrun on its input
> or output buffers. In my case, the input buffer was overflowing, apparently
> due to an infinite recursion, and corrupting the symbol table.
>
> Now while one could argue that I shouldn't be using m4 if I'm not smart
> enough to know that whenever it dumps core it's because the input buffer has
> overflowed due to infinite recursion :-), the following patch seems to do a
> reasonable job of making m4 a little more user-friendly in this situation.
> Incidentally, I also rewrote the put macro while I was at it :-) -- it's now
> an expression rather than a statement.
>
> While I'm at it, is there a more modern and/or free version of m4 out
> there? How about source for other interesting macro pre-processors?
>
> Bart Massey
>
> Tektronix, Inc.
> TV Systems Engineering
> M.S. 58-639
> P.O. Box 500
> Beaverton, OR 97077
> (503) 627-5320
>
> ..tektronix!videovax.tv.tek.com!bart
>
>
> *** /tmp/,RCSt1013776 Wed Mar 7 21:29:50 1990
> --- m4.c Wed Mar 7 21:28:47 1990
> ***************
> *** 35,43 ****
> #define SAVS 4096
> #define TOKS 128
>
> ! #define putbak(c) *ip++ = c;
> ! #define getchr() (ip>cur_ip?*--ip: getc(infile[infptr]))
> ! #define putchr(c) if (cp==NULL) {if (curfile)putc(c,curfile);} else
*op++ = c
> char type[] = {
> 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0, 0, 0, 0, 0, 0,
> --- 35,56 ----
> #define SAVS 4096
> #define TOKS 128
>
> ! puterr()
> ! {
> ! fprintf( stderr, "m4: output buffer overflow\n" );
> ! delexit();
> ! }
> !
> ! putbakerr()
> ! {
> ! fprintf( stderr, "m4: input buffer overflow (infinite recursion?)\n" );
> ! delexit();
> ! }
> !
> ! #define putbak(c) ((ip<ibuf+sizeof(ibuf))?(*ip++ = (c)):putbakerr())
> ! #define getchr() ((ip>cur_ip)?*--ip:getc(infile[infptr]))
> ! #define putchr(c)
(cp?((op<obuf+sizeof(obuf))?(*op++=(c)):puterr()):(curfile?putc((c),curf
file):0))
> !
> char type[] = {
> 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0, 0, 0, 0, 0, 0,
Jonathan Kamens USnail:
MIT Project Athena 11 Ashford Terrace
jik@Athena.MIT.EDU Allston, MA 02134
Office: 617-253-8495 Home: 617-782-0710
