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Make the m4 machine stack dynamically sized.

Fix strspace automatic extension.
The assumption that simply updating the current pointer works is false,
there are cases where previous entries on the stack would absorp vast
amounts of string space, and overload the non-updated entries.

To fix it, we use a shadow copy of the stack, which only records which
entries are pointers within strspace, so that a resize can adjust all
those pointers at once.

Reviewed by millert@

/*	$OpenBSD: main.c,v 1.34 2000/07/02 01:17:00 espie Exp $	*/
/*	$NetBSD: main.c,v 1.12 1997/02/08 23:54:49 cgd Exp $	*/

/*-
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ozan Yigit at York University.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1989, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)main.c	8.1 (Berkeley) 6/6/93";
#else
static char rcsid[] = "$OpenBSD: main.c,v 1.34 2000/07/02 01:17:00 espie Exp $";
#endif
#endif /* not lint */

/*
 * main.c
 * Facility: m4 macro processor
 * by: oz
 */

#include <sys/types.h>
#include <assert.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <err.h>
#include "mdef.h"
#include "stdd.h"
#include "extern.h"
#include "pathnames.h"

ndptr hashtab[HASHSIZE];	/* hash table for macros etc.  */
stae *mstack;		 	/* stack of m4 machine         */
char *sstack;		 	/* shadow stack, for string space extension */
static size_t STACKMAX;		/* current maximum size of stack */
int sp; 			/* current m4  stack pointer   */
int fp; 			/* m4 call frame pointer       */
struct input_file infile[MAXINP];/* input file stack (0=stdin)  */
FILE *outfile[MAXOUT];		/* diversion array(0=bitbucket)*/
FILE *active;			/* active output file pointer  */
int ilevel = 0; 		/* input file stack pointer    */
int oindex = 0; 		/* diversion index..	       */
char *null = "";                /* as it says.. just a null..  */
char *m4wraps = "";             /* m4wrap string default..     */
char lquote[MAXCCHARS+1] = {LQUOTE};	/* left quote character  (`)   */
char rquote[MAXCCHARS+1] = {RQUOTE};	/* right quote character (')   */
char scommt[MAXCCHARS+1] = {SCOMMT};	/* start character for comment */
char ecommt[MAXCCHARS+1] = {ECOMMT};	/* end character for comment   */

struct keyblk keywrds[] = {	/* m4 keywords to be installed */
	{ "include",      INCLTYPE },
	{ "sinclude",     SINCTYPE },
	{ "define",       DEFITYPE },
	{ "defn",         DEFNTYPE },
	{ "divert",       DIVRTYPE | NOARGS },
	{ "expr",         EXPRTYPE },
	{ "eval",         EXPRTYPE },
	{ "substr",       SUBSTYPE },
	{ "ifelse",       IFELTYPE },
	{ "ifdef",        IFDFTYPE },
	{ "len",          LENGTYPE },
	{ "incr",         INCRTYPE },
	{ "decr",         DECRTYPE },
	{ "dnl",          DNLNTYPE | NOARGS },
	{ "changequote",  CHNQTYPE | NOARGS },
	{ "changecom",    CHNCTYPE | NOARGS },
	{ "index",        INDXTYPE },
#ifdef EXTENDED
	{ "paste",        PASTTYPE },
	{ "spaste",       SPASTYPE },
    	/* Newer extensions, needed to handle gnu-m4 scripts */
	{ "indir",        INDIRTYPE},
	{ "builtin",      BUILTINTYPE},
	{ "patsubst",	  PATSTYPE},
	{ "regexp",	  REGEXPTYPE},
	{ "__file__",	  FILENAMETYPE | NOARGS},
	{ "__line__",	  LINETYPE | NOARGS},
#endif
	{ "popdef",       POPDTYPE },
	{ "pushdef",      PUSDTYPE },
	{ "dumpdef",      DUMPTYPE | NOARGS },
	{ "shift",        SHIFTYPE | NOARGS },
	{ "translit",     TRNLTYPE },
	{ "undefine",     UNDFTYPE },
	{ "undivert",     UNDVTYPE | NOARGS },
	{ "divnum",       DIVNTYPE | NOARGS },
	{ "maketemp",     MKTMTYPE },
	{ "errprint",     ERRPTYPE | NOARGS },
	{ "m4wrap",       M4WRTYPE | NOARGS },
	{ "m4exit",       EXITTYPE | NOARGS },
	{ "syscmd",       SYSCTYPE },
	{ "sysval",       SYSVTYPE | NOARGS },

#if defined(unix) || defined(__unix__) 
	{ "unix",         SELFTYPE | NOARGS },
#else
#ifdef vms
	{ "vms",          SELFTYPE | NOARGS },
#endif
#endif
};

#define MAXKEYS	(sizeof(keywrds)/sizeof(struct keyblk))

extern int optind;
extern char *optarg;

#define MAXRECORD 50
static struct position {
	char *name;
	unsigned long line;
} quotes[MAXRECORD], paren[MAXRECORD];

static void record __P((struct position *, int));
static void dump_stack __P((struct position *, int));

static void macro __P((void));
static void initkwds __P((void));
static ndptr inspect __P((char, char *));
static int do_look_ahead __P((int, const char *));

static void enlarge_stack __P((void));

int main __P((int, char *[]));

int
main(argc,argv)
	int argc;
	char *argv[];
{
	int c;
	int n;
	char *p;
	FILE *ifp;

	if (signal(SIGINT, SIG_IGN) != SIG_IGN)
		signal(SIGINT, onintr);

	initkwds();
	initspaces();
	STACKMAX = INITSTACKMAX;

	mstack = (stae *)xalloc(sizeof(stae) * STACKMAX);
	sstack = (char *)xalloc(STACKMAX);

	while ((c = getopt(argc, argv, "gtD:U:o:I:")) != -1)
		switch(c) {

		case 'D':               /* define something..*/
			for (p = optarg; *p; p++)
				if (*p == '=')
					break;
			if (*p)
				*p++ = EOS;
			dodefine(optarg, p);
			break;
		case 'I':
			addtoincludepath(optarg);
			break;
		case 'U':               /* undefine...       */
			remhash(optarg, TOP);
			break;
		case 'g':
			mimic_gnu = 1;
			break;
		case 'o':		/* specific output   */
		case '?':
			usage();
		}

        argc -= optind;
        argv += optind;

	active = stdout;		/* default active output     */
	bbase[0] = bufbase;
        if (!argc) {
 		sp = -1;		/* stack pointer initialized */
		fp = 0; 		/* frame pointer initialized */
		set_input(infile+0, stdin, "stdin");
					/* default input (naturally) */
		macro();
	} else
		for (; argc--; ++argv) {
			p = *argv;
			if (p[0] == '-' && p[1] == EOS)
				set_input(infile, stdin, "stdin");
			else if (fopen_trypath(infile, p) == NULL)
				err(1, "%s", p);
			sp = -1;
			fp = 0; 
			macro();
		    	release_input(infile);
		}

	if (*m4wraps) { 		/* anything for rundown ??   */
		ilevel = 0;		/* in case m4wrap includes.. */
		bufbase = bp = buf;	/* use the entire buffer   */
		pbstr(m4wraps); 	/* user-defined wrapup act   */
		macro();		/* last will and testament   */
	}

	if (active != stdout)
		active = stdout;	/* reset output just in case */
	for (n = 1; n < MAXOUT; n++)	/* default wrap-up: undivert */
		if (outfile[n] != NULL)
			getdiv(n);
					/* remove bitbucket if used  */
	if (outfile[0] != NULL) {
		(void) fclose(outfile[0]);
	}

	return 0;
}

/*
 * Look ahead for `token'.
 * (on input `t == token[0]')
 * Used for comment and quoting delimiters.
 * Returns 1 if `token' present; copied to output.
 *         0 if `token' not found; all characters pushed back
 */
static int
do_look_ahead(t, token)
	int	t;
	const char	*token;
{
	int i;

	assert(t == token[0]);

	for (i = 1; *++token; i++) {
		t = gpbc();
		if (t == EOF || t != *token) {
			putback(t);
			while (--i)
				putback(*--token);
			return 0;
		}
	}
	return 1;
}

#define LOOK_AHEAD(t, token) ((t)==(token)[0] && do_look_ahead(t,token))

/*
 * macro - the work horse..
 */
static void
macro()
{
	char token[MAXTOK+1];
	int t, l;
	ndptr p;
	int  nlpar;

	cycle {
		t = gpbc();
		if (t == '_' || isalpha(t)) {
			p = inspect(t, token);
			if (p != nil)
				putback(l = gpbc());
			if (p == nil || (l != LPAREN && 
			    (p->type & NEEDARGS) != 0))
				outputstr(token);
			else {
		/*
		 * real thing.. First build a call frame:
		 */
				pushf(fp);	/* previous call frm */
				pushf(p->type); /* type of the call  */
				pushf(0);	/* parenthesis level */
				fp = sp;	/* new frame pointer */
		/*
		 * now push the string arguments:
		 */
				pushs1(p->defn);	/* defn string */
				pushs1(p->name);	/* macro name  */
				pushs(ep);	      	/* start next..*/

				if (l != LPAREN)  {   /* add bracks  */
					putback(RPAREN);
					putback(LPAREN);
				}
			}
		}
		else if (t == EOF) {
			if (sp > -1) {
				warnx( "unexpected end of input, unclosed parenthesis:");
				dump_stack(paren, PARLEV);
				exit(1);
			}
			if (ilevel <= 0)
				break;			/* all done thanks.. */
			release_input(infile+ilevel--);
			bufbase = bbase[ilevel];
			continue;
		}
	/*
	 * non-alpha token possibly seen..
	 * [the order of else if .. stmts is important.]
	 */
		else if (LOOK_AHEAD(t,lquote)) {	/* strip quotes */
			nlpar = 0;
			record(quotes, nlpar++);
			/*
			 * Opening quote: scan forward until matching
			 * closing quote has been found.
			 */
			do {

				l = gpbc();
				if (LOOK_AHEAD(l,rquote)) {
					if (--nlpar > 0)
						outputstr(rquote);
				} else if (LOOK_AHEAD(l,lquote)) {
					record(quotes, nlpar++);
					outputstr(lquote);
				} else if (l == EOF) {
					if (nlpar == 1)
						warnx("unclosed quote:");
					else
						warnx("%d unclosed quotes:", nlpar);
					dump_stack(quotes, nlpar);
					exit(1);
				} else {
					if (nlpar > 0) {
						if (sp < 0)
							putc(l, active);
						else
							chrsave(l);
					}
				}
			}
			while (nlpar != 0);
		}

		else if (sp < 0 && LOOK_AHEAD(t, scommt)) {
			fputs(scommt, active);

			for(;;) {
				t = gpbc();
				if (LOOK_AHEAD(t, ecommt)) {
					fputs(ecommt, active);
					break;
				}
				if (t == EOF)
					break;
				putc(t, active);
			}
		}

		else if (sp < 0) {		/* not in a macro at all */
			putc(t, active);	/* output directly..	 */
		}

		else switch(t) {

		case LPAREN:
			if (PARLEV > 0)
				chrsave(t);
			while (isspace(l = gpbc()))
				;		/* skip blank, tab, nl.. */
			putback(l);
			record(paren, PARLEV++);
			break;

		case RPAREN:
			if (--PARLEV > 0)
				chrsave(t);
			else {			/* end of argument list */
				chrsave(EOS);

				if (sp == STACKMAX)
					errx(1, "internal stack overflow");

				if (CALTYP == MACRTYPE)
					expand((const char **) mstack+fp+1, sp-fp);
				else
					eval((const char **) mstack+fp+1, sp-fp, CALTYP);

				ep = PREVEP;	/* flush strspace */
				sp = PREVSP;	/* previous sp..  */
				fp = PREVFP;	/* rewind stack...*/
			}
			break;

		case COMMA:
			if (PARLEV == 1) {
				chrsave(EOS);		/* new argument   */
				while (isspace(l = gpbc()))
					;
				putback(l);
				pushs(ep);
			} else
				chrsave(t);
			break;

		default:
			if (LOOK_AHEAD(t, scommt)) {
				char *p;
				for (p = scommt; *p; p++)
					chrsave(*p);
				for(;;) {
					t = gpbc();
					if (LOOK_AHEAD(t, ecommt)) {
						for (p = ecommt; *p; p++)
							chrsave(*p);
						break;
					}
					if (t == EOF)
					    break;
					chrsave(t);
				}
			} else
				chrsave(t);		/* stack the char */
			break;
		}
	}
}

/* 
 * output string directly, without pushing it for reparses. 
 */
void
outputstr(s)
	const char *s;
{
	if (sp < 0)
		while (*s)
			putc(*s++, active);
	else
		while (*s)
			chrsave(*s++);
}

/*
 * build an input token..
 * consider only those starting with _ or A-Za-z. This is a
 * combo with lookup to speed things up.
 */
static ndptr
inspect(c, tp) 
	char c;
	char *tp;
{
	char *name = tp;
	char *etp = tp+MAXTOK;
	ndptr p;
	unsigned int h;
	
	h = *tp++ = c;

	while ((isalnum(c = gpbc()) || c == '_') && tp < etp)
		h = (h << 5) + h + (*tp++ = c);
	putback(c);
	*tp = EOS;
	/* token is too long, it won't match anything, but it can still
	 * be output. */
	if (tp == ep) {
		outputstr(name);
		while (isalnum(c = gpbc()) || c == '_') {
			if (sp < 0)
				putc(c, active);
			else
				chrsave(c);
		}
		*name = EOS;
		return nil;
	}

	for (p = hashtab[h % HASHSIZE]; p != nil; p = p->nxtptr)
		if (h == p->hv && STREQ(name, p->name))
			break;
	return p;
}

/*
 * initkwds - initialise m4 keywords as fast as possible. 
 * This very similar to install, but without certain overheads,
 * such as calling lookup. Malloc is not used for storing the 
 * keyword strings, since we simply use the static pointers
 * within keywrds block.
 */
static void
initkwds()
{
	size_t i;
	unsigned int h;
	ndptr p;

	for (i = 0; i < MAXKEYS; i++) {
		h = hash(keywrds[i].knam);
		p = (ndptr) xalloc(sizeof(struct ndblock));
		p->nxtptr = hashtab[h % HASHSIZE];
		hashtab[h % HASHSIZE] = p;
		p->name = keywrds[i].knam;
		p->defn = null;
		p->hv = h;
		p->type = (keywrds[i].ktyp & TYPEMASK) | STATIC;
		if ((keywrds[i].ktyp & NOARGS) == 0)
			p->type |= NEEDARGS;
	}
}

/* Look up a builtin type, even if overridden by the user */
int 
builtin_type(key)
	const char *key;
{
	int i;

	for (i = 0; i != MAXKEYS; i++)
		if (STREQ(keywrds[i].knam, key))
			return keywrds[i].ktyp;
	return -1;
}


static void
record(t, lev)
	struct position *t;
	int lev;
{
	if (lev < MAXRECORD) {
		t[lev].name = CURRENT_NAME;
		t[lev].line = CURRENT_LINE;
	}
}

static void
dump_stack(t, lev)
	struct position *t;
	int lev;
{
	int i;

	for (i = 0; i < lev; i++) {
		if (i == MAXRECORD) {
			fprintf(stderr, "   ...\n");
			break;
		}
		fprintf(stderr, "   %s at line %lu\n", 
			t[i].name, t[i].line);
	}
}


static void 
enlarge_stack()
{
	STACKMAX *= 2;
	fprintf(stderr, "%u\n", STACKMAX);
	mstack = realloc(mstack, sizeof(stae) * STACKMAX);
	sstack = realloc(sstack, STACKMAX);
	if (mstack == NULL || sstack == NULL)
		errx(1, "Evaluation stack overflow (%lu)", 
		    (unsigned long)STACKMAX);
}