xref: /freebsd/contrib/bmake/cond.c (revision 5ffd83dbcc34f10e07f6d3e968ae6365869615f4)
1 /*	$NetBSD: cond.c,v 1.79 2020/07/09 22:34:08 sjg Exp $	*/
2 
3 /*
4  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Adam de Boor.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 /*
36  * Copyright (c) 1988, 1989 by Adam de Boor
37  * Copyright (c) 1989 by Berkeley Softworks
38  * All rights reserved.
39  *
40  * This code is derived from software contributed to Berkeley by
41  * Adam de Boor.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  */
71 
72 #ifndef MAKE_NATIVE
73 static char rcsid[] = "$NetBSD: cond.c,v 1.79 2020/07/09 22:34:08 sjg Exp $";
74 #else
75 #include <sys/cdefs.h>
76 #ifndef lint
77 #if 0
78 static char sccsid[] = "@(#)cond.c	8.2 (Berkeley) 1/2/94";
79 #else
80 __RCSID("$NetBSD: cond.c,v 1.79 2020/07/09 22:34:08 sjg Exp $");
81 #endif
82 #endif /* not lint */
83 #endif
84 
85 /*-
86  * cond.c --
87  *	Functions to handle conditionals in a makefile.
88  *
89  * Interface:
90  *	Cond_Eval 	Evaluate the conditional in the passed line.
91  *
92  */
93 
94 #include    <assert.h>
95 #include    <ctype.h>
96 #include    <errno.h>    /* For strtoul() error checking */
97 
98 #include    "make.h"
99 #include    "hash.h"
100 #include    "dir.h"
101 #include    "buf.h"
102 
103 /*
104  * The parsing of conditional expressions is based on this grammar:
105  *	E -> F || E
106  *	E -> F
107  *	F -> T && F
108  *	F -> T
109  *	T -> defined(variable)
110  *	T -> make(target)
111  *	T -> exists(file)
112  *	T -> empty(varspec)
113  *	T -> target(name)
114  *	T -> commands(name)
115  *	T -> symbol
116  *	T -> $(varspec) op value
117  *	T -> $(varspec) == "string"
118  *	T -> $(varspec) != "string"
119  *	T -> "string"
120  *	T -> ( E )
121  *	T -> ! T
122  *	op -> == | != | > | < | >= | <=
123  *
124  * 'symbol' is some other symbol to which the default function (condDefProc)
125  * is applied.
126  *
127  * Tokens are scanned from the 'condExpr' string. The scanner (CondToken)
128  * will return TOK_AND for '&' and '&&', TOK_OR for '|' and '||',
129  * TOK_NOT for '!', TOK_LPAREN for '(', TOK_RPAREN for ')' and will evaluate
130  * the other terminal symbols, using either the default function or the
131  * function given in the terminal, and return the result as either TOK_TRUE
132  * or TOK_FALSE.
133  *
134  * TOK_FALSE is 0 and TOK_TRUE 1 so we can directly assign C comparisons.
135  *
136  * All Non-Terminal functions (CondE, CondF and CondT) return TOK_ERROR on
137  * error.
138  */
139 typedef enum {
140     TOK_FALSE = 0, TOK_TRUE = 1, TOK_AND, TOK_OR, TOK_NOT,
141     TOK_LPAREN, TOK_RPAREN, TOK_EOF, TOK_NONE, TOK_ERROR
142 } Token;
143 
144 /*-
145  * Structures to handle elegantly the different forms of #if's. The
146  * last two fields are stored in condInvert and condDefProc, respectively.
147  */
148 static void CondPushBack(Token);
149 static int CondGetArg(Boolean, char **, char **, const char *);
150 static Boolean CondDoDefined(int, const char *);
151 static int CondStrMatch(const void *, const void *);
152 static Boolean CondDoMake(int, const char *);
153 static Boolean CondDoExists(int, const char *);
154 static Boolean CondDoTarget(int, const char *);
155 static Boolean CondDoCommands(int, const char *);
156 static Boolean CondCvtArg(char *, double *);
157 static Token CondToken(Boolean);
158 static Token CondT(Boolean);
159 static Token CondF(Boolean);
160 static Token CondE(Boolean);
161 static int do_Cond_EvalExpression(Boolean *);
162 
163 static const struct If {
164     const char	*form;	      /* Form of if */
165     int		formlen;      /* Length of form */
166     Boolean	doNot;	      /* TRUE if default function should be negated */
167     Boolean	(*defProc)(int, const char *); /* Default function to apply */
168 } ifs[] = {
169     { "def",	  3,	  FALSE,  CondDoDefined },
170     { "ndef",	  4,	  TRUE,	  CondDoDefined },
171     { "make",	  4,	  FALSE,  CondDoMake },
172     { "nmake",	  5,	  TRUE,	  CondDoMake },
173     { "",	  0,	  FALSE,  CondDoDefined },
174     { NULL,	  0,	  FALSE,  NULL }
175 };
176 
177 static const struct If *if_info;        /* Info for current statement */
178 static char 	  *condExpr;	    	/* The expression to parse */
179 static Token	  condPushBack=TOK_NONE;	/* Single push-back token used in
180 					 * parsing */
181 
182 static unsigned int	cond_depth = 0;  	/* current .if nesting level */
183 static unsigned int	cond_min_depth = 0;  	/* depth at makefile open */
184 
185 /*
186  * Indicate when we should be strict about lhs of comparisons.
187  * TRUE when Cond_EvalExpression is called from Cond_Eval (.if etc)
188  * FALSE when Cond_EvalExpression is called from var.c:ApplyModifiers
189  * since lhs is already expanded and we cannot tell if
190  * it was a variable reference or not.
191  */
192 static Boolean lhsStrict;
193 
194 static int
195 istoken(const char *str, const char *tok, size_t len)
196 {
197 	return strncmp(str, tok, len) == 0 && !isalpha((unsigned char)str[len]);
198 }
199 
200 /*-
201  *-----------------------------------------------------------------------
202  * CondPushBack --
203  *	Push back the most recent token read. We only need one level of
204  *	this, so the thing is just stored in 'condPushback'.
205  *
206  * Input:
207  *	t		Token to push back into the "stream"
208  *
209  * Results:
210  *	None.
211  *
212  * Side Effects:
213  *	condPushback is overwritten.
214  *
215  *-----------------------------------------------------------------------
216  */
217 static void
218 CondPushBack(Token t)
219 {
220     condPushBack = t;
221 }
222 
223 /*-
224  *-----------------------------------------------------------------------
225  * CondGetArg --
226  *	Find the argument of a built-in function.
227  *
228  * Results:
229  *	The length of the argument and the address of the argument.
230  *
231  * Side Effects:
232  *	The pointer is set to point to the closing parenthesis of the
233  *	function call.
234  *
235  *-----------------------------------------------------------------------
236  */
237 static int
238 CondGetArg(Boolean doEval, char **linePtr, char **argPtr, const char *func)
239 {
240     char	  *cp;
241     int	    	  argLen;
242     Buffer	  buf;
243     int           paren_depth;
244     char          ch;
245 
246     cp = *linePtr;
247     if (func != NULL)
248 	/* Skip opening '(' - verfied by caller */
249 	cp++;
250 
251     if (*cp == '\0') {
252 	/*
253 	 * No arguments whatsoever. Because 'make' and 'defined' aren't really
254 	 * "reserved words", we don't print a message. I think this is better
255 	 * than hitting the user with a warning message every time s/he uses
256 	 * the word 'make' or 'defined' at the beginning of a symbol...
257 	 */
258 	*argPtr = NULL;
259 	return 0;
260     }
261 
262     while (*cp == ' ' || *cp == '\t') {
263 	cp++;
264     }
265 
266     /*
267      * Create a buffer for the argument and start it out at 16 characters
268      * long. Why 16? Why not?
269      */
270     Buf_Init(&buf, 16);
271 
272     paren_depth = 0;
273     for (;;) {
274 	ch = *cp;
275 	if (ch == 0 || ch == ' ' || ch == '\t')
276 	    break;
277 	if ((ch == '&' || ch == '|') && paren_depth == 0)
278 	    break;
279 	if (*cp == '$') {
280 	    /*
281 	     * Parse the variable spec and install it as part of the argument
282 	     * if it's valid. We tell Var_Parse to complain on an undefined
283 	     * variable, so we don't do it too. Nor do we return an error,
284 	     * though perhaps we should...
285 	     */
286 	    char  	*cp2;
287 	    int		len;
288 	    void	*freeIt;
289 
290 	    cp2 = Var_Parse(cp, VAR_CMD, VARF_UNDEFERR|
291 			    (doEval ? VARF_WANTRES : 0),
292 			    &len, &freeIt);
293 	    Buf_AddBytes(&buf, strlen(cp2), cp2);
294 	    free(freeIt);
295 	    cp += len;
296 	    continue;
297 	}
298 	if (ch == '(')
299 	    paren_depth++;
300 	else
301 	    if (ch == ')' && --paren_depth < 0)
302 		break;
303 	Buf_AddByte(&buf, *cp);
304 	cp++;
305     }
306 
307     *argPtr = Buf_GetAll(&buf, &argLen);
308     Buf_Destroy(&buf, FALSE);
309 
310     while (*cp == ' ' || *cp == '\t') {
311 	cp++;
312     }
313 
314     if (func != NULL && *cp++ != ')') {
315 	Parse_Error(PARSE_WARNING, "Missing closing parenthesis for %s()",
316 		     func);
317 	return 0;
318     }
319 
320     *linePtr = cp;
321     return argLen;
322 }
323 
324 /*-
325  *-----------------------------------------------------------------------
326  * CondDoDefined --
327  *	Handle the 'defined' function for conditionals.
328  *
329  * Results:
330  *	TRUE if the given variable is defined.
331  *
332  * Side Effects:
333  *	None.
334  *
335  *-----------------------------------------------------------------------
336  */
337 static Boolean
338 CondDoDefined(int argLen MAKE_ATTR_UNUSED, const char *arg)
339 {
340     char    *p1;
341     Boolean result;
342 
343     if (Var_Value(arg, VAR_CMD, &p1) != NULL) {
344 	result = TRUE;
345     } else {
346 	result = FALSE;
347     }
348 
349     free(p1);
350     return result;
351 }
352 
353 /*-
354  *-----------------------------------------------------------------------
355  * CondStrMatch --
356  *	Front-end for Str_Match so it returns 0 on match and non-zero
357  *	on mismatch. Callback function for CondDoMake via Lst_Find
358  *
359  * Results:
360  *	0 if string matches pattern
361  *
362  * Side Effects:
363  *	None
364  *
365  *-----------------------------------------------------------------------
366  */
367 static int
368 CondStrMatch(const void *string, const void *pattern)
369 {
370     return !Str_Match(string, pattern);
371 }
372 
373 /*-
374  *-----------------------------------------------------------------------
375  * CondDoMake --
376  *	Handle the 'make' function for conditionals.
377  *
378  * Results:
379  *	TRUE if the given target is being made.
380  *
381  * Side Effects:
382  *	None.
383  *
384  *-----------------------------------------------------------------------
385  */
386 static Boolean
387 CondDoMake(int argLen MAKE_ATTR_UNUSED, const char *arg)
388 {
389     return Lst_Find(create, arg, CondStrMatch) != NULL;
390 }
391 
392 /*-
393  *-----------------------------------------------------------------------
394  * CondDoExists --
395  *	See if the given file exists.
396  *
397  * Results:
398  *	TRUE if the file exists and FALSE if it does not.
399  *
400  * Side Effects:
401  *	None.
402  *
403  *-----------------------------------------------------------------------
404  */
405 static Boolean
406 CondDoExists(int argLen MAKE_ATTR_UNUSED, const char *arg)
407 {
408     Boolean result;
409     char    *path;
410 
411     path = Dir_FindFile(arg, dirSearchPath);
412     if (DEBUG(COND)) {
413 	fprintf(debug_file, "exists(%s) result is \"%s\"\n",
414 	       arg, path ? path : "");
415     }
416     if (path != NULL) {
417 	result = TRUE;
418 	free(path);
419     } else {
420 	result = FALSE;
421     }
422     return result;
423 }
424 
425 /*-
426  *-----------------------------------------------------------------------
427  * CondDoTarget --
428  *	See if the given node exists and is an actual target.
429  *
430  * Results:
431  *	TRUE if the node exists as a target and FALSE if it does not.
432  *
433  * Side Effects:
434  *	None.
435  *
436  *-----------------------------------------------------------------------
437  */
438 static Boolean
439 CondDoTarget(int argLen MAKE_ATTR_UNUSED, const char *arg)
440 {
441     GNode   *gn;
442 
443     gn = Targ_FindNode(arg, TARG_NOCREATE);
444     return gn != NULL && !OP_NOP(gn->type);
445 }
446 
447 /*-
448  *-----------------------------------------------------------------------
449  * CondDoCommands --
450  *	See if the given node exists and is an actual target with commands
451  *	associated with it.
452  *
453  * Results:
454  *	TRUE if the node exists as a target and has commands associated with
455  *	it and FALSE if it does not.
456  *
457  * Side Effects:
458  *	None.
459  *
460  *-----------------------------------------------------------------------
461  */
462 static Boolean
463 CondDoCommands(int argLen MAKE_ATTR_UNUSED, const char *arg)
464 {
465     GNode   *gn;
466 
467     gn = Targ_FindNode(arg, TARG_NOCREATE);
468     return gn != NULL && !OP_NOP(gn->type) && !Lst_IsEmpty(gn->commands);
469 }
470 
471 /*-
472  *-----------------------------------------------------------------------
473  * CondCvtArg --
474  *	Convert the given number into a double.
475  *	We try a base 10 or 16 integer conversion first, if that fails
476  *	then we try a floating point conversion instead.
477  *
478  * Results:
479  *	Sets 'value' to double value of string.
480  *	Returns 'true' if the convertion suceeded
481  *
482  *-----------------------------------------------------------------------
483  */
484 static Boolean
485 CondCvtArg(char *str, double *value)
486 {
487     char *eptr, ech;
488     unsigned long l_val;
489     double d_val;
490 
491     errno = 0;
492     if (!*str) {
493 	*value = (double)0;
494 	return TRUE;
495     }
496     l_val = strtoul(str, &eptr, str[1] == 'x' ? 16 : 10);
497     ech = *eptr;
498     if (ech == 0 && errno != ERANGE) {
499 	d_val = str[0] == '-' ? -(double)-l_val : (double)l_val;
500     } else {
501 	if (ech != 0 && ech != '.' && ech != 'e' && ech != 'E')
502 	    return FALSE;
503 	d_val = strtod(str, &eptr);
504 	if (*eptr)
505 	    return FALSE;
506     }
507 
508     *value = d_val;
509     return TRUE;
510 }
511 
512 /*-
513  *-----------------------------------------------------------------------
514  * CondGetString --
515  *	Get a string from a variable reference or an optionally quoted
516  *	string.  This is called for the lhs and rhs of string compares.
517  *
518  * Results:
519  *	Sets freeIt if needed,
520  *	Sets quoted if string was quoted,
521  *	Returns NULL on error,
522  *	else returns string - absent any quotes.
523  *
524  * Side Effects:
525  *	Moves condExpr to end of this token.
526  *
527  *
528  *-----------------------------------------------------------------------
529  */
530 /* coverity:[+alloc : arg-*2] */
531 static char *
532 CondGetString(Boolean doEval, Boolean *quoted, void **freeIt, Boolean strictLHS)
533 {
534     Buffer buf;
535     char *cp;
536     char *str;
537     int	len;
538     int qt;
539     char *start;
540 
541     Buf_Init(&buf, 0);
542     str = NULL;
543     *freeIt = NULL;
544     *quoted = qt = *condExpr == '"' ? 1 : 0;
545     if (qt)
546 	condExpr++;
547     for (start = condExpr; *condExpr && str == NULL; condExpr++) {
548 	switch (*condExpr) {
549 	case '\\':
550 	    if (condExpr[1] != '\0') {
551 		condExpr++;
552 		Buf_AddByte(&buf, *condExpr);
553 	    }
554 	    break;
555 	case '"':
556 	    if (qt) {
557 		condExpr++;		/* we don't want the quotes */
558 		goto got_str;
559 	    } else
560 		Buf_AddByte(&buf, *condExpr); /* likely? */
561 	    break;
562 	case ')':
563 	case '!':
564 	case '=':
565 	case '>':
566 	case '<':
567 	case ' ':
568 	case '\t':
569 	    if (!qt)
570 		goto got_str;
571 	    else
572 		Buf_AddByte(&buf, *condExpr);
573 	    break;
574 	case '$':
575 	    /* if we are in quotes, then an undefined variable is ok */
576 	    str = Var_Parse(condExpr, VAR_CMD,
577 			    ((!qt && doEval) ? VARF_UNDEFERR : 0) |
578 			    (doEval ? VARF_WANTRES : 0), &len, freeIt);
579 	    if (str == var_Error) {
580 		if (*freeIt) {
581 		    free(*freeIt);
582 		    *freeIt = NULL;
583 		}
584 		/*
585 		 * Even if !doEval, we still report syntax errors, which
586 		 * is what getting var_Error back with !doEval means.
587 		 */
588 		str = NULL;
589 		goto cleanup;
590 	    }
591 	    condExpr += len;
592 	    /*
593 	     * If the '$' was first char (no quotes), and we are
594 	     * followed by space, the operator or end of expression,
595 	     * we are done.
596 	     */
597 	    if ((condExpr == start + len) &&
598 		(*condExpr == '\0' ||
599 		 isspace((unsigned char) *condExpr) ||
600 		 strchr("!=><)", *condExpr))) {
601 		goto cleanup;
602 	    }
603 	    /*
604 	     * Nope, we better copy str to buf
605 	     */
606 	    for (cp = str; *cp; cp++) {
607 		Buf_AddByte(&buf, *cp);
608 	    }
609 	    if (*freeIt) {
610 		free(*freeIt);
611 		*freeIt = NULL;
612 	    }
613 	    str = NULL;			/* not finished yet */
614 	    condExpr--;			/* don't skip over next char */
615 	    break;
616 	default:
617 	    if (strictLHS && !qt && *start != '$' &&
618 		!isdigit((unsigned char) *start)) {
619 		/* lhs must be quoted, a variable reference or number */
620 		if (*freeIt) {
621 		    free(*freeIt);
622 		    *freeIt = NULL;
623 		}
624 		str = NULL;
625 		goto cleanup;
626 	    }
627 	    Buf_AddByte(&buf, *condExpr);
628 	    break;
629 	}
630     }
631  got_str:
632     str = Buf_GetAll(&buf, NULL);
633     *freeIt = str;
634  cleanup:
635     Buf_Destroy(&buf, FALSE);
636     return str;
637 }
638 
639 /*-
640  *-----------------------------------------------------------------------
641  * CondToken --
642  *	Return the next token from the input.
643  *
644  * Results:
645  *	A Token for the next lexical token in the stream.
646  *
647  * Side Effects:
648  *	condPushback will be set back to TOK_NONE if it is used.
649  *
650  *-----------------------------------------------------------------------
651  */
652 static Token
653 compare_expression(Boolean doEval)
654 {
655     Token	t;
656     char	*lhs;
657     char	*rhs;
658     char	*op;
659     void	*lhsFree;
660     void	*rhsFree;
661     Boolean lhsQuoted;
662     Boolean rhsQuoted;
663     double  	left, right;
664 
665     t = TOK_ERROR;
666     rhs = NULL;
667     lhsFree = rhsFree = FALSE;
668     lhsQuoted = rhsQuoted = FALSE;
669 
670     /*
671      * Parse the variable spec and skip over it, saving its
672      * value in lhs.
673      */
674     lhs = CondGetString(doEval, &lhsQuoted, &lhsFree, lhsStrict);
675     if (!lhs)
676 	goto done;
677 
678     /*
679      * Skip whitespace to get to the operator
680      */
681     while (isspace((unsigned char) *condExpr))
682 	condExpr++;
683 
684     /*
685      * Make sure the operator is a valid one. If it isn't a
686      * known relational operator, pretend we got a
687      * != 0 comparison.
688      */
689     op = condExpr;
690     switch (*condExpr) {
691 	case '!':
692 	case '=':
693 	case '<':
694 	case '>':
695 	    if (condExpr[1] == '=') {
696 		condExpr += 2;
697 	    } else {
698 		condExpr += 1;
699 	    }
700 	    break;
701 	default:
702 	    if (!doEval) {
703 		t = TOK_FALSE;
704 		goto done;
705 	    }
706 	    /* For .ifxxx "..." check for non-empty string. */
707 	    if (lhsQuoted) {
708 		t = lhs[0] != 0;
709 		goto done;
710 	    }
711 	    /* For .ifxxx <number> compare against zero */
712 	    if (CondCvtArg(lhs, &left)) {
713 		t = left != 0.0;
714 		goto done;
715 	    }
716 	    /* For .if ${...} check for non-empty string (defProc is ifdef). */
717 	    if (if_info->form[0] == 0) {
718 		t = lhs[0] != 0;
719 		goto done;
720 	    }
721 	    /* Otherwise action default test ... */
722 	    t = if_info->defProc(strlen(lhs), lhs) != if_info->doNot;
723 	    goto done;
724     }
725 
726     while (isspace((unsigned char)*condExpr))
727 	condExpr++;
728 
729     if (*condExpr == '\0') {
730 	Parse_Error(PARSE_WARNING,
731 		    "Missing right-hand-side of operator");
732 	goto done;
733     }
734 
735     rhs = CondGetString(doEval, &rhsQuoted, &rhsFree, FALSE);
736     if (!rhs)
737 	goto done;
738 
739     if (!doEval) {
740 	t = TOK_FALSE;
741 	goto done;
742     }
743 
744     if (rhsQuoted || lhsQuoted) {
745 do_string_compare:
746 	if (((*op != '!') && (*op != '=')) || (op[1] != '=')) {
747 	    Parse_Error(PARSE_WARNING,
748     "String comparison operator should be either == or !=");
749 	    goto done;
750 	}
751 
752 	if (DEBUG(COND)) {
753 	    fprintf(debug_file, "lhs = \"%s\", rhs = \"%s\", op = %.2s\n",
754 		   lhs, rhs, op);
755 	}
756 	/*
757 	 * Null-terminate rhs and perform the comparison.
758 	 * t is set to the result.
759 	 */
760 	if (*op == '=') {
761 	    t = strcmp(lhs, rhs) == 0;
762 	} else {
763 	    t = strcmp(lhs, rhs) != 0;
764 	}
765     } else {
766 	/*
767 	 * rhs is either a float or an integer. Convert both the
768 	 * lhs and the rhs to a double and compare the two.
769 	 */
770 
771 	if (!CondCvtArg(lhs, &left) || !CondCvtArg(rhs, &right))
772 	    goto do_string_compare;
773 
774 	if (DEBUG(COND)) {
775 	    fprintf(debug_file, "left = %f, right = %f, op = %.2s\n", left,
776 		   right, op);
777 	}
778 	switch(op[0]) {
779 	case '!':
780 	    if (op[1] != '=') {
781 		Parse_Error(PARSE_WARNING,
782 			    "Unknown operator");
783 		goto done;
784 	    }
785 	    t = (left != right);
786 	    break;
787 	case '=':
788 	    if (op[1] != '=') {
789 		Parse_Error(PARSE_WARNING,
790 			    "Unknown operator");
791 		goto done;
792 	    }
793 	    t = (left == right);
794 	    break;
795 	case '<':
796 	    if (op[1] == '=') {
797 		t = (left <= right);
798 	    } else {
799 		t = (left < right);
800 	    }
801 	    break;
802 	case '>':
803 	    if (op[1] == '=') {
804 		t = (left >= right);
805 	    } else {
806 		t = (left > right);
807 	    }
808 	    break;
809 	}
810     }
811 
812 done:
813     free(lhsFree);
814     free(rhsFree);
815     return t;
816 }
817 
818 static int
819 get_mpt_arg(Boolean doEval, char **linePtr, char **argPtr, const char *func MAKE_ATTR_UNUSED)
820 {
821     /*
822      * Use Var_Parse to parse the spec in parens and return
823      * TOK_TRUE if the resulting string is empty.
824      */
825     int	    length;
826     void    *freeIt;
827     char    *val;
828     char    *cp = *linePtr;
829 
830     /* We do all the work here and return the result as the length */
831     *argPtr = NULL;
832 
833     val = Var_Parse(cp - 1, VAR_CMD, doEval ? VARF_WANTRES : 0, &length, &freeIt);
834     /*
835      * Advance *linePtr to beyond the closing ). Note that
836      * we subtract one because 'length' is calculated from 'cp - 1'.
837      */
838     *linePtr = cp - 1 + length;
839 
840     if (val == var_Error) {
841 	free(freeIt);
842 	return -1;
843     }
844 
845     /* A variable is empty when it just contains spaces... 4/15/92, christos */
846     while (isspace(*(unsigned char *)val))
847 	val++;
848 
849     /*
850      * For consistency with the other functions we can't generate the
851      * true/false here.
852      */
853     length = *val ? 2 : 1;
854     free(freeIt);
855     return length;
856 }
857 
858 static Boolean
859 CondDoEmpty(int arglen, const char *arg MAKE_ATTR_UNUSED)
860 {
861     return arglen == 1;
862 }
863 
864 static Token
865 compare_function(Boolean doEval)
866 {
867     static const struct fn_def {
868 	const char  *fn_name;
869 	int         fn_name_len;
870         int         (*fn_getarg)(Boolean, char **, char **, const char *);
871 	Boolean     (*fn_proc)(int, const char *);
872     } fn_defs[] = {
873 	{ "defined",   7, CondGetArg, CondDoDefined },
874 	{ "make",      4, CondGetArg, CondDoMake },
875 	{ "exists",    6, CondGetArg, CondDoExists },
876 	{ "empty",     5, get_mpt_arg, CondDoEmpty },
877 	{ "target",    6, CondGetArg, CondDoTarget },
878 	{ "commands",  8, CondGetArg, CondDoCommands },
879 	{ NULL,        0, NULL, NULL },
880     };
881     const struct fn_def *fn_def;
882     Token	t;
883     char	*arg = NULL;
884     int	arglen;
885     char *cp = condExpr;
886     char *cp1;
887 
888     for (fn_def = fn_defs; fn_def->fn_name != NULL; fn_def++) {
889 	if (!istoken(cp, fn_def->fn_name, fn_def->fn_name_len))
890 	    continue;
891 	cp += fn_def->fn_name_len;
892 	/* There can only be whitespace before the '(' */
893 	while (isspace(*(unsigned char *)cp))
894 	    cp++;
895 	if (*cp != '(')
896 	    break;
897 
898 	arglen = fn_def->fn_getarg(doEval, &cp, &arg, fn_def->fn_name);
899 	if (arglen <= 0) {
900 	    condExpr = cp;
901 	    return arglen < 0 ? TOK_ERROR : TOK_FALSE;
902 	}
903 	/* Evaluate the argument using the required function. */
904 	t = !doEval || fn_def->fn_proc(arglen, arg);
905 	free(arg);
906 	condExpr = cp;
907 	return t;
908     }
909 
910     /* Push anything numeric through the compare expression */
911     cp = condExpr;
912     if (isdigit((unsigned char)cp[0]) || strchr("+-", cp[0]))
913 	return compare_expression(doEval);
914 
915     /*
916      * Most likely we have a naked token to apply the default function to.
917      * However ".if a == b" gets here when the "a" is unquoted and doesn't
918      * start with a '$'. This surprises people.
919      * If what follows the function argument is a '=' or '!' then the syntax
920      * would be invalid if we did "defined(a)" - so instead treat as an
921      * expression.
922      */
923     arglen = CondGetArg(doEval, &cp, &arg, NULL);
924     for (cp1 = cp; isspace(*(unsigned char *)cp1); cp1++)
925 	continue;
926     if (*cp1 == '=' || *cp1 == '!')
927 	return compare_expression(doEval);
928     condExpr = cp;
929 
930     /*
931      * Evaluate the argument using the default function.
932      * This path always treats .if as .ifdef. To get here the character
933      * after .if must have been taken literally, so the argument cannot
934      * be empty - even if it contained a variable expansion.
935      */
936     t = !doEval || if_info->defProc(arglen, arg) != if_info->doNot;
937     free(arg);
938     return t;
939 }
940 
941 static Token
942 CondToken(Boolean doEval)
943 {
944     Token t;
945 
946     t = condPushBack;
947     if (t != TOK_NONE) {
948 	condPushBack = TOK_NONE;
949 	return t;
950     }
951 
952     while (*condExpr == ' ' || *condExpr == '\t') {
953 	condExpr++;
954     }
955 
956     switch (*condExpr) {
957 
958     case '(':
959 	condExpr++;
960 	return TOK_LPAREN;
961 
962     case ')':
963 	condExpr++;
964 	return TOK_RPAREN;
965 
966     case '|':
967 	if (condExpr[1] == '|') {
968 	    condExpr++;
969 	}
970 	condExpr++;
971 	return TOK_OR;
972 
973     case '&':
974 	if (condExpr[1] == '&') {
975 	    condExpr++;
976 	}
977 	condExpr++;
978 	return TOK_AND;
979 
980     case '!':
981 	condExpr++;
982 	return TOK_NOT;
983 
984     case '#':
985     case '\n':
986     case '\0':
987 	return TOK_EOF;
988 
989     case '"':
990     case '$':
991 	return compare_expression(doEval);
992 
993     default:
994 	return compare_function(doEval);
995     }
996 }
997 
998 /*-
999  *-----------------------------------------------------------------------
1000  * CondT --
1001  *	Parse a single term in the expression. This consists of a terminal
1002  *	symbol or TOK_NOT and a terminal symbol (not including the binary
1003  *	operators):
1004  *	    T -> defined(variable) | make(target) | exists(file) | symbol
1005  *	    T -> ! T | ( E )
1006  *
1007  * Results:
1008  *	TOK_TRUE, TOK_FALSE or TOK_ERROR.
1009  *
1010  * Side Effects:
1011  *	Tokens are consumed.
1012  *
1013  *-----------------------------------------------------------------------
1014  */
1015 static Token
1016 CondT(Boolean doEval)
1017 {
1018     Token   t;
1019 
1020     t = CondToken(doEval);
1021 
1022     if (t == TOK_EOF) {
1023 	/*
1024 	 * If we reached the end of the expression, the expression
1025 	 * is malformed...
1026 	 */
1027 	t = TOK_ERROR;
1028     } else if (t == TOK_LPAREN) {
1029 	/*
1030 	 * T -> ( E )
1031 	 */
1032 	t = CondE(doEval);
1033 	if (t != TOK_ERROR) {
1034 	    if (CondToken(doEval) != TOK_RPAREN) {
1035 		t = TOK_ERROR;
1036 	    }
1037 	}
1038     } else if (t == TOK_NOT) {
1039 	t = CondT(doEval);
1040 	if (t == TOK_TRUE) {
1041 	    t = TOK_FALSE;
1042 	} else if (t == TOK_FALSE) {
1043 	    t = TOK_TRUE;
1044 	}
1045     }
1046     return t;
1047 }
1048 
1049 /*-
1050  *-----------------------------------------------------------------------
1051  * CondF --
1052  *	Parse a conjunctive factor (nice name, wot?)
1053  *	    F -> T && F | T
1054  *
1055  * Results:
1056  *	TOK_TRUE, TOK_FALSE or TOK_ERROR
1057  *
1058  * Side Effects:
1059  *	Tokens are consumed.
1060  *
1061  *-----------------------------------------------------------------------
1062  */
1063 static Token
1064 CondF(Boolean doEval)
1065 {
1066     Token   l, o;
1067 
1068     l = CondT(doEval);
1069     if (l != TOK_ERROR) {
1070 	o = CondToken(doEval);
1071 
1072 	if (o == TOK_AND) {
1073 	    /*
1074 	     * F -> T && F
1075 	     *
1076 	     * If T is TOK_FALSE, the whole thing will be TOK_FALSE, but we have to
1077 	     * parse the r.h.s. anyway (to throw it away).
1078 	     * If T is TOK_TRUE, the result is the r.h.s., be it an TOK_ERROR or no.
1079 	     */
1080 	    if (l == TOK_TRUE) {
1081 		l = CondF(doEval);
1082 	    } else {
1083 		(void)CondF(FALSE);
1084 	    }
1085 	} else {
1086 	    /*
1087 	     * F -> T
1088 	     */
1089 	    CondPushBack(o);
1090 	}
1091     }
1092     return l;
1093 }
1094 
1095 /*-
1096  *-----------------------------------------------------------------------
1097  * CondE --
1098  *	Main expression production.
1099  *	    E -> F || E | F
1100  *
1101  * Results:
1102  *	TOK_TRUE, TOK_FALSE or TOK_ERROR.
1103  *
1104  * Side Effects:
1105  *	Tokens are, of course, consumed.
1106  *
1107  *-----------------------------------------------------------------------
1108  */
1109 static Token
1110 CondE(Boolean doEval)
1111 {
1112     Token   l, o;
1113 
1114     l = CondF(doEval);
1115     if (l != TOK_ERROR) {
1116 	o = CondToken(doEval);
1117 
1118 	if (o == TOK_OR) {
1119 	    /*
1120 	     * E -> F || E
1121 	     *
1122 	     * A similar thing occurs for ||, except that here we make sure
1123 	     * the l.h.s. is TOK_FALSE before we bother to evaluate the r.h.s.
1124 	     * Once again, if l is TOK_FALSE, the result is the r.h.s. and once
1125 	     * again if l is TOK_TRUE, we parse the r.h.s. to throw it away.
1126 	     */
1127 	    if (l == TOK_FALSE) {
1128 		l = CondE(doEval);
1129 	    } else {
1130 		(void)CondE(FALSE);
1131 	    }
1132 	} else {
1133 	    /*
1134 	     * E -> F
1135 	     */
1136 	    CondPushBack(o);
1137 	}
1138     }
1139     return l;
1140 }
1141 
1142 /*-
1143  *-----------------------------------------------------------------------
1144  * Cond_EvalExpression --
1145  *	Evaluate an expression in the passed line. The expression
1146  *	consists of &&, ||, !, make(target), defined(variable)
1147  *	and parenthetical groupings thereof.
1148  *
1149  * Results:
1150  *	COND_PARSE	if the condition was valid grammatically
1151  *	COND_INVALID  	if not a valid conditional.
1152  *
1153  *	(*value) is set to the boolean value of the condition
1154  *
1155  * Side Effects:
1156  *	None.
1157  *
1158  *-----------------------------------------------------------------------
1159  */
1160 int
1161 Cond_EvalExpression(const struct If *info, char *line, Boolean *value, int eprint, Boolean strictLHS)
1162 {
1163     static const struct If *dflt_info;
1164     const struct If *sv_if_info = if_info;
1165     char *sv_condExpr = condExpr;
1166     Token sv_condPushBack = condPushBack;
1167     int rval;
1168 
1169     lhsStrict = strictLHS;
1170 
1171     while (*line == ' ' || *line == '\t')
1172 	line++;
1173 
1174     if (info == NULL && (info = dflt_info) == NULL) {
1175 	/* Scan for the entry for .if - it can't be first */
1176 	for (info = ifs; ; info++)
1177 	    if (info->form[0] == 0)
1178 		break;
1179 	dflt_info = info;
1180     }
1181     assert(info != NULL);
1182 
1183     if_info = info;
1184     condExpr = line;
1185     condPushBack = TOK_NONE;
1186 
1187     rval = do_Cond_EvalExpression(value);
1188 
1189     if (rval == COND_INVALID && eprint)
1190 	Parse_Error(PARSE_FATAL, "Malformed conditional (%s)", line);
1191 
1192     if_info = sv_if_info;
1193     condExpr = sv_condExpr;
1194     condPushBack = sv_condPushBack;
1195 
1196     return rval;
1197 }
1198 
1199 static int
1200 do_Cond_EvalExpression(Boolean *value)
1201 {
1202 
1203     switch (CondE(TRUE)) {
1204     case TOK_TRUE:
1205 	if (CondToken(TRUE) == TOK_EOF) {
1206 	    *value = TRUE;
1207 	    return COND_PARSE;
1208 	}
1209 	break;
1210     case TOK_FALSE:
1211 	if (CondToken(TRUE) == TOK_EOF) {
1212 	    *value = FALSE;
1213 	    return COND_PARSE;
1214 	}
1215 	break;
1216     default:
1217     case TOK_ERROR:
1218 	break;
1219     }
1220 
1221     return COND_INVALID;
1222 }
1223 
1224 
1225 /*-
1226  *-----------------------------------------------------------------------
1227  * Cond_Eval --
1228  *	Evaluate the conditional in the passed line. The line
1229  *	looks like this:
1230  *	    .<cond-type> <expr>
1231  *	where <cond-type> is any of if, ifmake, ifnmake, ifdef,
1232  *	ifndef, elif, elifmake, elifnmake, elifdef, elifndef
1233  *	and <expr> consists of &&, ||, !, make(target), defined(variable)
1234  *	and parenthetical groupings thereof.
1235  *
1236  * Input:
1237  *	line		Line to parse
1238  *
1239  * Results:
1240  *	COND_PARSE	if should parse lines after the conditional
1241  *	COND_SKIP	if should skip lines after the conditional
1242  *	COND_INVALID  	if not a valid conditional.
1243  *
1244  * Side Effects:
1245  *	None.
1246  *
1247  * Note that the states IF_ACTIVE and ELSE_ACTIVE are only different in order
1248  * to detect splurious .else lines (as are SKIP_TO_ELSE and SKIP_TO_ENDIF)
1249  * otherwise .else could be treated as '.elif 1'.
1250  *
1251  *-----------------------------------------------------------------------
1252  */
1253 int
1254 Cond_Eval(char *line)
1255 {
1256 #define	    MAXIF      128	/* maximum depth of .if'ing */
1257 #define	    MAXIF_BUMP  32	/* how much to grow by */
1258     enum if_states {
1259 	IF_ACTIVE,		/* .if or .elif part active */
1260 	ELSE_ACTIVE,		/* .else part active */
1261 	SEARCH_FOR_ELIF,	/* searching for .elif/else to execute */
1262 	SKIP_TO_ELSE,           /* has been true, but not seen '.else' */
1263 	SKIP_TO_ENDIF		/* nothing else to execute */
1264     };
1265     static enum if_states *cond_state = NULL;
1266     static unsigned int max_if_depth = MAXIF;
1267 
1268     const struct If *ifp;
1269     Boolean 	    isElif;
1270     Boolean 	    value;
1271     int	    	    level;  	/* Level at which to report errors. */
1272     enum if_states  state;
1273 
1274     level = PARSE_FATAL;
1275     if (!cond_state) {
1276 	cond_state = bmake_malloc(max_if_depth * sizeof(*cond_state));
1277 	cond_state[0] = IF_ACTIVE;
1278     }
1279     /* skip leading character (the '.') and any whitespace */
1280     for (line++; *line == ' ' || *line == '\t'; line++)
1281 	continue;
1282 
1283     /* Find what type of if we're dealing with.  */
1284     if (line[0] == 'e') {
1285 	if (line[1] != 'l') {
1286 	    if (!istoken(line + 1, "ndif", 4))
1287 		return COND_INVALID;
1288 	    /* End of conditional section */
1289 	    if (cond_depth == cond_min_depth) {
1290 		Parse_Error(level, "if-less endif");
1291 		return COND_PARSE;
1292 	    }
1293 	    /* Return state for previous conditional */
1294 	    cond_depth--;
1295 	    return cond_state[cond_depth] <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1296 	}
1297 
1298 	/* Quite likely this is 'else' or 'elif' */
1299 	line += 2;
1300 	if (istoken(line, "se", 2)) {
1301 	    /* It is else... */
1302 	    if (cond_depth == cond_min_depth) {
1303 		Parse_Error(level, "if-less else");
1304 		return COND_PARSE;
1305 	    }
1306 
1307 	    state = cond_state[cond_depth];
1308 	    switch (state) {
1309 	    case SEARCH_FOR_ELIF:
1310 		state = ELSE_ACTIVE;
1311 		break;
1312 	    case ELSE_ACTIVE:
1313 	    case SKIP_TO_ENDIF:
1314 		Parse_Error(PARSE_WARNING, "extra else");
1315 		/* FALLTHROUGH */
1316 	    default:
1317 	    case IF_ACTIVE:
1318 	    case SKIP_TO_ELSE:
1319 		state = SKIP_TO_ENDIF;
1320 		break;
1321 	    }
1322 	    cond_state[cond_depth] = state;
1323 	    return state <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1324 	}
1325 	/* Assume for now it is an elif */
1326 	isElif = TRUE;
1327     } else
1328 	isElif = FALSE;
1329 
1330     if (line[0] != 'i' || line[1] != 'f')
1331 	/* Not an ifxxx or elifxxx line */
1332 	return COND_INVALID;
1333 
1334     /*
1335      * Figure out what sort of conditional it is -- what its default
1336      * function is, etc. -- by looking in the table of valid "ifs"
1337      */
1338     line += 2;
1339     for (ifp = ifs; ; ifp++) {
1340 	if (ifp->form == NULL)
1341 	    return COND_INVALID;
1342 	if (istoken(ifp->form, line, ifp->formlen)) {
1343 	    line += ifp->formlen;
1344 	    break;
1345 	}
1346     }
1347 
1348     /* Now we know what sort of 'if' it is... */
1349 
1350     if (isElif) {
1351 	if (cond_depth == cond_min_depth) {
1352 	    Parse_Error(level, "if-less elif");
1353 	    return COND_PARSE;
1354 	}
1355 	state = cond_state[cond_depth];
1356 	if (state == SKIP_TO_ENDIF || state == ELSE_ACTIVE) {
1357 	    Parse_Error(PARSE_WARNING, "extra elif");
1358 	    cond_state[cond_depth] = SKIP_TO_ENDIF;
1359 	    return COND_SKIP;
1360 	}
1361 	if (state != SEARCH_FOR_ELIF) {
1362 	    /* Either just finished the 'true' block, or already SKIP_TO_ELSE */
1363 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1364 	    return COND_SKIP;
1365 	}
1366     } else {
1367 	/* Normal .if */
1368 	if (cond_depth + 1 >= max_if_depth) {
1369 	    /*
1370 	     * This is rare, but not impossible.
1371 	     * In meta mode, dirdeps.mk (only runs at level 0)
1372 	     * can need more than the default.
1373 	     */
1374 	    max_if_depth += MAXIF_BUMP;
1375 	    cond_state = bmake_realloc(cond_state, max_if_depth *
1376 		sizeof(*cond_state));
1377 	}
1378 	state = cond_state[cond_depth];
1379 	cond_depth++;
1380 	if (state > ELSE_ACTIVE) {
1381 	    /* If we aren't parsing the data, treat as always false */
1382 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1383 	    return COND_SKIP;
1384 	}
1385     }
1386 
1387     /* And evaluate the conditional expresssion */
1388     if (Cond_EvalExpression(ifp, line, &value, 1, TRUE) == COND_INVALID) {
1389 	/* Syntax error in conditional, error message already output. */
1390 	/* Skip everything to matching .endif */
1391 	cond_state[cond_depth] = SKIP_TO_ELSE;
1392 	return COND_SKIP;
1393     }
1394 
1395     if (!value) {
1396 	cond_state[cond_depth] = SEARCH_FOR_ELIF;
1397 	return COND_SKIP;
1398     }
1399     cond_state[cond_depth] = IF_ACTIVE;
1400     return COND_PARSE;
1401 }
1402 
1403 
1404 
1405 /*-
1406  *-----------------------------------------------------------------------
1407  * Cond_End --
1408  *	Make sure everything's clean at the end of a makefile.
1409  *
1410  * Results:
1411  *	None.
1412  *
1413  * Side Effects:
1414  *	Parse_Error will be called if open conditionals are around.
1415  *
1416  *-----------------------------------------------------------------------
1417  */
1418 void
1419 Cond_restore_depth(unsigned int saved_depth)
1420 {
1421     int open_conds = cond_depth - cond_min_depth;
1422 
1423     if (open_conds != 0 || saved_depth > cond_depth) {
1424 	Parse_Error(PARSE_FATAL, "%d open conditional%s", open_conds,
1425 		    open_conds == 1 ? "" : "s");
1426 	cond_depth = cond_min_depth;
1427     }
1428 
1429     cond_min_depth = saved_depth;
1430 }
1431 
1432 unsigned int
1433 Cond_save_depth(void)
1434 {
1435     int depth = cond_min_depth;
1436 
1437     cond_min_depth = cond_depth;
1438     return depth;
1439 }
1440