xref: /freebsd/contrib/bmake/cond.c (revision 65b71c48d226f3ef3eb1c4452dccc678a7d2ac96)
1 /*	$NetBSD: cond.c,v 1.68 2015/05/05 21:51:09 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 1.68 2015/05/05 21:51:09 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 1.68 2015/05/05 21:51:09 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    <ctype.h>
95 #include    <errno.h>    /* For strtoul() error checking */
96 
97 #include    "make.h"
98 #include    "hash.h"
99 #include    "dir.h"
100 #include    "buf.h"
101 
102 /*
103  * The parsing of conditional expressions is based on this grammar:
104  *	E -> F || E
105  *	E -> F
106  *	F -> T && F
107  *	F -> T
108  *	T -> defined(variable)
109  *	T -> make(target)
110  *	T -> exists(file)
111  *	T -> empty(varspec)
112  *	T -> target(name)
113  *	T -> commands(name)
114  *	T -> symbol
115  *	T -> $(varspec) op value
116  *	T -> $(varspec) == "string"
117  *	T -> $(varspec) != "string"
118  *	T -> "string"
119  *	T -> ( E )
120  *	T -> ! T
121  *	op -> == | != | > | < | >= | <=
122  *
123  * 'symbol' is some other symbol to which the default function (condDefProc)
124  * is applied.
125  *
126  * Tokens are scanned from the 'condExpr' string. The scanner (CondToken)
127  * will return TOK_AND for '&' and '&&', TOK_OR for '|' and '||',
128  * TOK_NOT for '!', TOK_LPAREN for '(', TOK_RPAREN for ')' and will evaluate
129  * the other terminal symbols, using either the default function or the
130  * function given in the terminal, and return the result as either TOK_TRUE
131  * or TOK_FALSE.
132  *
133  * TOK_FALSE is 0 and TOK_TRUE 1 so we can directly assign C comparisons.
134  *
135  * All Non-Terminal functions (CondE, CondF and CondT) return TOK_ERROR on
136  * error.
137  */
138 typedef enum {
139     TOK_FALSE = 0, TOK_TRUE = 1, TOK_AND, TOK_OR, TOK_NOT,
140     TOK_LPAREN, TOK_RPAREN, TOK_EOF, TOK_NONE, TOK_ERROR
141 } Token;
142 
143 /*-
144  * Structures to handle elegantly the different forms of #if's. The
145  * last two fields are stored in condInvert and condDefProc, respectively.
146  */
147 static void CondPushBack(Token);
148 static int CondGetArg(char **, char **, const char *);
149 static Boolean CondDoDefined(int, const char *);
150 static int CondStrMatch(const void *, const void *);
151 static Boolean CondDoMake(int, const char *);
152 static Boolean CondDoExists(int, const char *);
153 static Boolean CondDoTarget(int, const char *);
154 static Boolean CondDoCommands(int, const char *);
155 static Boolean CondCvtArg(char *, double *);
156 static Token CondToken(Boolean);
157 static Token CondT(Boolean);
158 static Token CondF(Boolean);
159 static Token CondE(Boolean);
160 static int do_Cond_EvalExpression(Boolean *);
161 
162 static const struct If {
163     const char	*form;	      /* Form of if */
164     int		formlen;      /* Length of form */
165     Boolean	doNot;	      /* TRUE if default function should be negated */
166     Boolean	(*defProc)(int, const char *); /* Default function to apply */
167 } ifs[] = {
168     { "def",	  3,	  FALSE,  CondDoDefined },
169     { "ndef",	  4,	  TRUE,	  CondDoDefined },
170     { "make",	  4,	  FALSE,  CondDoMake },
171     { "nmake",	  5,	  TRUE,	  CondDoMake },
172     { "",	  0,	  FALSE,  CondDoDefined },
173     { NULL,	  0,	  FALSE,  NULL }
174 };
175 
176 static const struct If *if_info;        /* Info for current statement */
177 static char 	  *condExpr;	    	/* The expression to parse */
178 static Token	  condPushBack=TOK_NONE;	/* Single push-back token used in
179 					 * parsing */
180 
181 static unsigned int	cond_depth = 0;  	/* current .if nesting level */
182 static unsigned int	cond_min_depth = 0;  	/* depth at makefile open */
183 
184 /*
185  * Indicate when we should be strict about lhs of comparisons.
186  * TRUE when Cond_EvalExpression is called from Cond_Eval (.if etc)
187  * FALSE when Cond_EvalExpression is called from var.c:ApplyModifiers
188  * since lhs is already expanded and we cannot tell if
189  * it was a variable reference or not.
190  */
191 static Boolean lhsStrict;
192 
193 static int
194 istoken(const char *str, const char *tok, size_t len)
195 {
196 	return strncmp(str, tok, len) == 0 && !isalpha((unsigned char)str[len]);
197 }
198 
199 /*-
200  *-----------------------------------------------------------------------
201  * CondPushBack --
202  *	Push back the most recent token read. We only need one level of
203  *	this, so the thing is just stored in 'condPushback'.
204  *
205  * Input:
206  *	t		Token to push back into the "stream"
207  *
208  * Results:
209  *	None.
210  *
211  * Side Effects:
212  *	condPushback is overwritten.
213  *
214  *-----------------------------------------------------------------------
215  */
216 static void
217 CondPushBack(Token t)
218 {
219     condPushBack = t;
220 }
221 
222 /*-
223  *-----------------------------------------------------------------------
224  * CondGetArg --
225  *	Find the argument of a built-in function.
226  *
227  * Input:
228  *	parens		TRUE if arg should be bounded by parens
229  *
230  * Results:
231  *	The length of the argument and the address of the argument.
232  *
233  * Side Effects:
234  *	The pointer is set to point to the closing parenthesis of the
235  *	function call.
236  *
237  *-----------------------------------------------------------------------
238  */
239 static int
240 CondGetArg(char **linePtr, char **argPtr, const char *func)
241 {
242     char	  *cp;
243     int	    	  argLen;
244     Buffer	  buf;
245     int           paren_depth;
246     char          ch;
247 
248     cp = *linePtr;
249     if (func != NULL)
250 	/* Skip opening '(' - verfied by caller */
251 	cp++;
252 
253     if (*cp == '\0') {
254 	/*
255 	 * No arguments whatsoever. Because 'make' and 'defined' aren't really
256 	 * "reserved words", we don't print a message. I think this is better
257 	 * than hitting the user with a warning message every time s/he uses
258 	 * the word 'make' or 'defined' at the beginning of a symbol...
259 	 */
260 	*argPtr = NULL;
261 	return (0);
262     }
263 
264     while (*cp == ' ' || *cp == '\t') {
265 	cp++;
266     }
267 
268     /*
269      * Create a buffer for the argument and start it out at 16 characters
270      * long. Why 16? Why not?
271      */
272     Buf_Init(&buf, 16);
273 
274     paren_depth = 0;
275     for (;;) {
276 	ch = *cp;
277 	if (ch == 0 || ch == ' ' || ch == '\t')
278 	    break;
279 	if ((ch == '&' || ch == '|') && paren_depth == 0)
280 	    break;
281 	if (*cp == '$') {
282 	    /*
283 	     * Parse the variable spec and install it as part of the argument
284 	     * if it's valid. We tell Var_Parse to complain on an undefined
285 	     * variable, so we don't do it too. Nor do we return an error,
286 	     * though perhaps we should...
287 	     */
288 	    char  	*cp2;
289 	    int		len;
290 	    void	*freeIt;
291 
292 	    cp2 = Var_Parse(cp, VAR_CMD, TRUE, &len, &freeIt);
293 	    Buf_AddBytes(&buf, strlen(cp2), cp2);
294 	    if (freeIt)
295 		free(freeIt);
296 	    cp += len;
297 	    continue;
298 	}
299 	if (ch == '(')
300 	    paren_depth++;
301 	else
302 	    if (ch == ')' && --paren_depth < 0)
303 		break;
304 	Buf_AddByte(&buf, *cp);
305 	cp++;
306     }
307 
308     *argPtr = Buf_GetAll(&buf, &argLen);
309     Buf_Destroy(&buf, FALSE);
310 
311     while (*cp == ' ' || *cp == '\t') {
312 	cp++;
313     }
314 
315     if (func != NULL && *cp++ != ')') {
316 	Parse_Error(PARSE_WARNING, "Missing closing parenthesis for %s()",
317 		     func);
318 	return (0);
319     }
320 
321     *linePtr = cp;
322     return (argLen);
323 }
324 
325 /*-
326  *-----------------------------------------------------------------------
327  * CondDoDefined --
328  *	Handle the 'defined' function for conditionals.
329  *
330  * Results:
331  *	TRUE if the given variable is defined.
332  *
333  * Side Effects:
334  *	None.
335  *
336  *-----------------------------------------------------------------------
337  */
338 static Boolean
339 CondDoDefined(int argLen MAKE_ATTR_UNUSED, const char *arg)
340 {
341     char    *p1;
342     Boolean result;
343 
344     if (Var_Value(arg, VAR_CMD, &p1) != NULL) {
345 	result = TRUE;
346     } else {
347 	result = FALSE;
348     }
349     if (p1)
350 	free(p1);
351     return (result);
352 }
353 
354 /*-
355  *-----------------------------------------------------------------------
356  * CondStrMatch --
357  *	Front-end for Str_Match so it returns 0 on match and non-zero
358  *	on mismatch. Callback function for CondDoMake via Lst_Find
359  *
360  * Results:
361  *	0 if string matches pattern
362  *
363  * Side Effects:
364  *	None
365  *
366  *-----------------------------------------------------------------------
367  */
368 static int
369 CondStrMatch(const void *string, const void *pattern)
370 {
371     return(!Str_Match(string, pattern));
372 }
373 
374 /*-
375  *-----------------------------------------------------------------------
376  * CondDoMake --
377  *	Handle the 'make' function for conditionals.
378  *
379  * Results:
380  *	TRUE if the given target is being made.
381  *
382  * Side Effects:
383  *	None.
384  *
385  *-----------------------------------------------------------------------
386  */
387 static Boolean
388 CondDoMake(int argLen MAKE_ATTR_UNUSED, const char *arg)
389 {
390     return Lst_Find(create, arg, CondStrMatch) != NULL;
391 }
392 
393 /*-
394  *-----------------------------------------------------------------------
395  * CondDoExists --
396  *	See if the given file exists.
397  *
398  * Results:
399  *	TRUE if the file exists and FALSE if it does not.
400  *
401  * Side Effects:
402  *	None.
403  *
404  *-----------------------------------------------------------------------
405  */
406 static Boolean
407 CondDoExists(int argLen MAKE_ATTR_UNUSED, const char *arg)
408 {
409     Boolean result;
410     char    *path;
411 
412     path = Dir_FindFile(arg, dirSearchPath);
413     if (DEBUG(COND)) {
414 	fprintf(debug_file, "exists(%s) result is \"%s\"\n",
415 	       arg, path ? path : "");
416     }
417     if (path != NULL) {
418 	result = TRUE;
419 	free(path);
420     } else {
421 	result = FALSE;
422     }
423     return (result);
424 }
425 
426 /*-
427  *-----------------------------------------------------------------------
428  * CondDoTarget --
429  *	See if the given node exists and is an actual target.
430  *
431  * Results:
432  *	TRUE if the node exists as a target and FALSE if it does not.
433  *
434  * Side Effects:
435  *	None.
436  *
437  *-----------------------------------------------------------------------
438  */
439 static Boolean
440 CondDoTarget(int argLen MAKE_ATTR_UNUSED, const char *arg)
441 {
442     GNode   *gn;
443 
444     gn = Targ_FindNode(arg, TARG_NOCREATE);
445     return (gn != NULL) && !OP_NOP(gn->type);
446 }
447 
448 /*-
449  *-----------------------------------------------------------------------
450  * CondDoCommands --
451  *	See if the given node exists and is an actual target with commands
452  *	associated with it.
453  *
454  * Results:
455  *	TRUE if the node exists as a target and has commands associated with
456  *	it and FALSE if it does not.
457  *
458  * Side Effects:
459  *	None.
460  *
461  *-----------------------------------------------------------------------
462  */
463 static Boolean
464 CondDoCommands(int argLen MAKE_ATTR_UNUSED, const char *arg)
465 {
466     GNode   *gn;
467 
468     gn = Targ_FindNode(arg, TARG_NOCREATE);
469     return (gn != NULL) && !OP_NOP(gn->type) && !Lst_IsEmpty(gn->commands);
470 }
471 
472 /*-
473  *-----------------------------------------------------------------------
474  * CondCvtArg --
475  *	Convert the given number into a double.
476  *	We try a base 10 or 16 integer conversion first, if that fails
477  *	then we try a floating point conversion instead.
478  *
479  * Results:
480  *	Sets 'value' to double value of string.
481  *	Returns 'true' if the convertion suceeded
482  *
483  *-----------------------------------------------------------------------
484  */
485 static Boolean
486 CondCvtArg(char *str, double *value)
487 {
488     char *eptr, ech;
489     unsigned long l_val;
490     double d_val;
491 
492     errno = 0;
493     l_val = strtoul(str, &eptr, str[1] == 'x' ? 16 : 10);
494     ech = *eptr;
495     if (ech == 0 && errno != ERANGE) {
496 	d_val = str[0] == '-' ? -(double)-l_val : (double)l_val;
497     } else {
498 	if (ech != 0 && ech != '.' && ech != 'e' && ech != 'E')
499 	    return FALSE;
500 	d_val = strtod(str, &eptr);
501 	if (*eptr)
502 	    return FALSE;
503     }
504 
505     *value = d_val;
506     return TRUE;
507 }
508 
509 /*-
510  *-----------------------------------------------------------------------
511  * CondGetString --
512  *	Get a string from a variable reference or an optionally quoted
513  *	string.  This is called for the lhs and rhs of string compares.
514  *
515  * Results:
516  *	Sets freeIt if needed,
517  *	Sets quoted if string was quoted,
518  *	Returns NULL on error,
519  *	else returns string - absent any quotes.
520  *
521  * Side Effects:
522  *	Moves condExpr to end of this token.
523  *
524  *
525  *-----------------------------------------------------------------------
526  */
527 /* coverity:[+alloc : arg-*2] */
528 static char *
529 CondGetString(Boolean doEval, Boolean *quoted, void **freeIt, Boolean strictLHS)
530 {
531     Buffer buf;
532     char *cp;
533     char *str;
534     int	len;
535     int qt;
536     char *start;
537 
538     Buf_Init(&buf, 0);
539     str = NULL;
540     *freeIt = NULL;
541     *quoted = qt = *condExpr == '"' ? 1 : 0;
542     if (qt)
543 	condExpr++;
544     for (start = condExpr; *condExpr && str == NULL; condExpr++) {
545 	switch (*condExpr) {
546 	case '\\':
547 	    if (condExpr[1] != '\0') {
548 		condExpr++;
549 		Buf_AddByte(&buf, *condExpr);
550 	    }
551 	    break;
552 	case '"':
553 	    if (qt) {
554 		condExpr++;		/* we don't want the quotes */
555 		goto got_str;
556 	    } else
557 		Buf_AddByte(&buf, *condExpr); /* likely? */
558 	    break;
559 	case ')':
560 	case '!':
561 	case '=':
562 	case '>':
563 	case '<':
564 	case ' ':
565 	case '\t':
566 	    if (!qt)
567 		goto got_str;
568 	    else
569 		Buf_AddByte(&buf, *condExpr);
570 	    break;
571 	case '$':
572 	    /* if we are in quotes, then an undefined variable is ok */
573 	    str = Var_Parse(condExpr, VAR_CMD, (qt ? 0 : doEval),
574 			    &len, freeIt);
575 	    if (str == var_Error) {
576 		if (*freeIt) {
577 		    free(*freeIt);
578 		    *freeIt = NULL;
579 		}
580 		/*
581 		 * Even if !doEval, we still report syntax errors, which
582 		 * is what getting var_Error back with !doEval means.
583 		 */
584 		str = NULL;
585 		goto cleanup;
586 	    }
587 	    condExpr += len;
588 	    /*
589 	     * If the '$' was first char (no quotes), and we are
590 	     * followed by space, the operator or end of expression,
591 	     * we are done.
592 	     */
593 	    if ((condExpr == start + len) &&
594 		(*condExpr == '\0' ||
595 		 isspace((unsigned char) *condExpr) ||
596 		 strchr("!=><)", *condExpr))) {
597 		goto cleanup;
598 	    }
599 	    /*
600 	     * Nope, we better copy str to buf
601 	     */
602 	    for (cp = str; *cp; cp++) {
603 		Buf_AddByte(&buf, *cp);
604 	    }
605 	    if (*freeIt) {
606 		free(*freeIt);
607 		*freeIt = NULL;
608 	    }
609 	    str = NULL;			/* not finished yet */
610 	    condExpr--;			/* don't skip over next char */
611 	    break;
612 	default:
613 	    if (strictLHS && !qt && *start != '$' &&
614 		!isdigit((unsigned char) *start)) {
615 		/* lhs must be quoted, a variable reference or number */
616 		if (*freeIt) {
617 		    free(*freeIt);
618 		    *freeIt = NULL;
619 		}
620 		str = NULL;
621 		goto cleanup;
622 	    }
623 	    Buf_AddByte(&buf, *condExpr);
624 	    break;
625 	}
626     }
627  got_str:
628     str = Buf_GetAll(&buf, NULL);
629     *freeIt = str;
630  cleanup:
631     Buf_Destroy(&buf, FALSE);
632     return str;
633 }
634 
635 /*-
636  *-----------------------------------------------------------------------
637  * CondToken --
638  *	Return the next token from the input.
639  *
640  * Results:
641  *	A Token for the next lexical token in the stream.
642  *
643  * Side Effects:
644  *	condPushback will be set back to TOK_NONE if it is used.
645  *
646  *-----------------------------------------------------------------------
647  */
648 static Token
649 compare_expression(Boolean doEval)
650 {
651     Token	t;
652     char	*lhs;
653     char	*rhs;
654     char	*op;
655     void	*lhsFree;
656     void	*rhsFree;
657     Boolean lhsQuoted;
658     Boolean rhsQuoted;
659     double  	left, right;
660 
661     t = TOK_ERROR;
662     rhs = NULL;
663     lhsFree = rhsFree = FALSE;
664     lhsQuoted = rhsQuoted = FALSE;
665 
666     /*
667      * Parse the variable spec and skip over it, saving its
668      * value in lhs.
669      */
670     lhs = CondGetString(doEval, &lhsQuoted, &lhsFree, lhsStrict);
671     if (!lhs)
672 	goto done;
673 
674     /*
675      * Skip whitespace to get to the operator
676      */
677     while (isspace((unsigned char) *condExpr))
678 	condExpr++;
679 
680     /*
681      * Make sure the operator is a valid one. If it isn't a
682      * known relational operator, pretend we got a
683      * != 0 comparison.
684      */
685     op = condExpr;
686     switch (*condExpr) {
687 	case '!':
688 	case '=':
689 	case '<':
690 	case '>':
691 	    if (condExpr[1] == '=') {
692 		condExpr += 2;
693 	    } else {
694 		condExpr += 1;
695 	    }
696 	    break;
697 	default:
698 	    if (!doEval) {
699 		t = TOK_FALSE;
700 		goto done;
701 	    }
702 	    /* For .ifxxx "..." check for non-empty string. */
703 	    if (lhsQuoted) {
704 		t = lhs[0] != 0;
705 		goto done;
706 	    }
707 	    /* For .ifxxx <number> compare against zero */
708 	    if (CondCvtArg(lhs, &left)) {
709 		t = left != 0.0;
710 		goto done;
711 	    }
712 	    /* For .if ${...} check for non-empty string (defProc is ifdef). */
713 	    if (if_info->form[0] == 0) {
714 		t = lhs[0] != 0;
715 		goto done;
716 	    }
717 	    /* Otherwise action default test ... */
718 	    t = if_info->defProc(strlen(lhs), lhs) != if_info->doNot;
719 	    goto done;
720     }
721 
722     while (isspace((unsigned char)*condExpr))
723 	condExpr++;
724 
725     if (*condExpr == '\0') {
726 	Parse_Error(PARSE_WARNING,
727 		    "Missing right-hand-side of operator");
728 	goto done;
729     }
730 
731     rhs = CondGetString(doEval, &rhsQuoted, &rhsFree, FALSE);
732     if (!rhs)
733 	goto done;
734 
735     if (rhsQuoted || lhsQuoted) {
736 do_string_compare:
737 	if (((*op != '!') && (*op != '=')) || (op[1] != '=')) {
738 	    Parse_Error(PARSE_WARNING,
739     "String comparison operator should be either == or !=");
740 	    goto done;
741 	}
742 
743 	if (DEBUG(COND)) {
744 	    fprintf(debug_file, "lhs = \"%s\", rhs = \"%s\", op = %.2s\n",
745 		   lhs, rhs, op);
746 	}
747 	/*
748 	 * Null-terminate rhs and perform the comparison.
749 	 * t is set to the result.
750 	 */
751 	if (*op == '=') {
752 	    t = strcmp(lhs, rhs) == 0;
753 	} else {
754 	    t = strcmp(lhs, rhs) != 0;
755 	}
756     } else {
757 	/*
758 	 * rhs is either a float or an integer. Convert both the
759 	 * lhs and the rhs to a double and compare the two.
760 	 */
761 
762 	if (!CondCvtArg(lhs, &left) || !CondCvtArg(rhs, &right))
763 	    goto do_string_compare;
764 
765 	if (DEBUG(COND)) {
766 	    fprintf(debug_file, "left = %f, right = %f, op = %.2s\n", left,
767 		   right, op);
768 	}
769 	switch(op[0]) {
770 	case '!':
771 	    if (op[1] != '=') {
772 		Parse_Error(PARSE_WARNING,
773 			    "Unknown operator");
774 		goto done;
775 	    }
776 	    t = (left != right);
777 	    break;
778 	case '=':
779 	    if (op[1] != '=') {
780 		Parse_Error(PARSE_WARNING,
781 			    "Unknown operator");
782 		goto done;
783 	    }
784 	    t = (left == right);
785 	    break;
786 	case '<':
787 	    if (op[1] == '=') {
788 		t = (left <= right);
789 	    } else {
790 		t = (left < right);
791 	    }
792 	    break;
793 	case '>':
794 	    if (op[1] == '=') {
795 		t = (left >= right);
796 	    } else {
797 		t = (left > right);
798 	    }
799 	    break;
800 	}
801     }
802 
803 done:
804     if (lhsFree)
805 	free(lhsFree);
806     if (rhsFree)
807 	free(rhsFree);
808     return t;
809 }
810 
811 static int
812 get_mpt_arg(char **linePtr, char **argPtr, const char *func MAKE_ATTR_UNUSED)
813 {
814     /*
815      * Use Var_Parse to parse the spec in parens and return
816      * TOK_TRUE if the resulting string is empty.
817      */
818     int	    length;
819     void    *freeIt;
820     char    *val;
821     char    *cp = *linePtr;
822 
823     /* We do all the work here and return the result as the length */
824     *argPtr = NULL;
825 
826     val = Var_Parse(cp - 1, VAR_CMD, FALSE, &length, &freeIt);
827     /*
828      * Advance *linePtr to beyond the closing ). Note that
829      * we subtract one because 'length' is calculated from 'cp - 1'.
830      */
831     *linePtr = cp - 1 + length;
832 
833     if (val == var_Error) {
834 	free(freeIt);
835 	return -1;
836     }
837 
838     /* A variable is empty when it just contains spaces... 4/15/92, christos */
839     while (isspace(*(unsigned char *)val))
840 	val++;
841 
842     /*
843      * For consistency with the other functions we can't generate the
844      * true/false here.
845      */
846     length = *val ? 2 : 1;
847     if (freeIt)
848 	free(freeIt);
849     return length;
850 }
851 
852 static Boolean
853 CondDoEmpty(int arglen, const char *arg MAKE_ATTR_UNUSED)
854 {
855     return arglen == 1;
856 }
857 
858 static Token
859 compare_function(Boolean doEval)
860 {
861     static const struct fn_def {
862 	const char  *fn_name;
863 	int         fn_name_len;
864         int         (*fn_getarg)(char **, char **, const char *);
865 	Boolean     (*fn_proc)(int, const char *);
866     } fn_defs[] = {
867 	{ "defined",   7, CondGetArg, CondDoDefined },
868 	{ "make",      4, CondGetArg, CondDoMake },
869 	{ "exists",    6, CondGetArg, CondDoExists },
870 	{ "empty",     5, get_mpt_arg, CondDoEmpty },
871 	{ "target",    6, CondGetArg, CondDoTarget },
872 	{ "commands",  8, CondGetArg, CondDoCommands },
873 	{ NULL,        0, NULL, NULL },
874     };
875     const struct fn_def *fn_def;
876     Token	t;
877     char	*arg = NULL;
878     int	arglen;
879     char *cp = condExpr;
880     char *cp1;
881 
882     for (fn_def = fn_defs; fn_def->fn_name != NULL; fn_def++) {
883 	if (!istoken(cp, fn_def->fn_name, fn_def->fn_name_len))
884 	    continue;
885 	cp += fn_def->fn_name_len;
886 	/* There can only be whitespace before the '(' */
887 	while (isspace(*(unsigned char *)cp))
888 	    cp++;
889 	if (*cp != '(')
890 	    break;
891 
892 	arglen = fn_def->fn_getarg(&cp, &arg, fn_def->fn_name);
893 	if (arglen <= 0) {
894 	    condExpr = cp;
895 	    return arglen < 0 ? TOK_ERROR : TOK_FALSE;
896 	}
897 	/* Evaluate the argument using the required function. */
898 	t = !doEval || fn_def->fn_proc(arglen, arg);
899 	if (arg)
900 	    free(arg);
901 	condExpr = cp;
902 	return t;
903     }
904 
905     /* Push anything numeric through the compare expression */
906     cp = condExpr;
907     if (isdigit((unsigned char)cp[0]) || strchr("+-", cp[0]))
908 	return compare_expression(doEval);
909 
910     /*
911      * Most likely we have a naked token to apply the default function to.
912      * However ".if a == b" gets here when the "a" is unquoted and doesn't
913      * start with a '$'. This surprises people.
914      * If what follows the function argument is a '=' or '!' then the syntax
915      * would be invalid if we did "defined(a)" - so instead treat as an
916      * expression.
917      */
918     arglen = CondGetArg(&cp, &arg, NULL);
919     for (cp1 = cp; isspace(*(unsigned char *)cp1); cp1++)
920 	continue;
921     if (*cp1 == '=' || *cp1 == '!')
922 	return compare_expression(doEval);
923     condExpr = cp;
924 
925     /*
926      * Evaluate the argument using the default function.
927      * This path always treats .if as .ifdef. To get here the character
928      * after .if must have been taken literally, so the argument cannot
929      * be empty - even if it contained a variable expansion.
930      */
931     t = !doEval || if_info->defProc(arglen, arg) != if_info->doNot;
932     if (arg)
933 	free(arg);
934     return t;
935 }
936 
937 static Token
938 CondToken(Boolean doEval)
939 {
940     Token t;
941 
942     t = condPushBack;
943     if (t != TOK_NONE) {
944 	condPushBack = TOK_NONE;
945 	return t;
946     }
947 
948     while (*condExpr == ' ' || *condExpr == '\t') {
949 	condExpr++;
950     }
951 
952     switch (*condExpr) {
953 
954     case '(':
955 	condExpr++;
956 	return TOK_LPAREN;
957 
958     case ')':
959 	condExpr++;
960 	return TOK_RPAREN;
961 
962     case '|':
963 	if (condExpr[1] == '|') {
964 	    condExpr++;
965 	}
966 	condExpr++;
967 	return TOK_OR;
968 
969     case '&':
970 	if (condExpr[1] == '&') {
971 	    condExpr++;
972 	}
973 	condExpr++;
974 	return TOK_AND;
975 
976     case '!':
977 	condExpr++;
978 	return TOK_NOT;
979 
980     case '#':
981     case '\n':
982     case '\0':
983 	return TOK_EOF;
984 
985     case '"':
986     case '$':
987 	return compare_expression(doEval);
988 
989     default:
990 	return compare_function(doEval);
991     }
992 }
993 
994 /*-
995  *-----------------------------------------------------------------------
996  * CondT --
997  *	Parse a single term in the expression. This consists of a terminal
998  *	symbol or TOK_NOT and a terminal symbol (not including the binary
999  *	operators):
1000  *	    T -> defined(variable) | make(target) | exists(file) | symbol
1001  *	    T -> ! T | ( E )
1002  *
1003  * Results:
1004  *	TOK_TRUE, TOK_FALSE or TOK_ERROR.
1005  *
1006  * Side Effects:
1007  *	Tokens are consumed.
1008  *
1009  *-----------------------------------------------------------------------
1010  */
1011 static Token
1012 CondT(Boolean doEval)
1013 {
1014     Token   t;
1015 
1016     t = CondToken(doEval);
1017 
1018     if (t == TOK_EOF) {
1019 	/*
1020 	 * If we reached the end of the expression, the expression
1021 	 * is malformed...
1022 	 */
1023 	t = TOK_ERROR;
1024     } else if (t == TOK_LPAREN) {
1025 	/*
1026 	 * T -> ( E )
1027 	 */
1028 	t = CondE(doEval);
1029 	if (t != TOK_ERROR) {
1030 	    if (CondToken(doEval) != TOK_RPAREN) {
1031 		t = TOK_ERROR;
1032 	    }
1033 	}
1034     } else if (t == TOK_NOT) {
1035 	t = CondT(doEval);
1036 	if (t == TOK_TRUE) {
1037 	    t = TOK_FALSE;
1038 	} else if (t == TOK_FALSE) {
1039 	    t = TOK_TRUE;
1040 	}
1041     }
1042     return (t);
1043 }
1044 
1045 /*-
1046  *-----------------------------------------------------------------------
1047  * CondF --
1048  *	Parse a conjunctive factor (nice name, wot?)
1049  *	    F -> T && F | T
1050  *
1051  * Results:
1052  *	TOK_TRUE, TOK_FALSE or TOK_ERROR
1053  *
1054  * Side Effects:
1055  *	Tokens are consumed.
1056  *
1057  *-----------------------------------------------------------------------
1058  */
1059 static Token
1060 CondF(Boolean doEval)
1061 {
1062     Token   l, o;
1063 
1064     l = CondT(doEval);
1065     if (l != TOK_ERROR) {
1066 	o = CondToken(doEval);
1067 
1068 	if (o == TOK_AND) {
1069 	    /*
1070 	     * F -> T && F
1071 	     *
1072 	     * If T is TOK_FALSE, the whole thing will be TOK_FALSE, but we have to
1073 	     * parse the r.h.s. anyway (to throw it away).
1074 	     * If T is TOK_TRUE, the result is the r.h.s., be it an TOK_ERROR or no.
1075 	     */
1076 	    if (l == TOK_TRUE) {
1077 		l = CondF(doEval);
1078 	    } else {
1079 		(void)CondF(FALSE);
1080 	    }
1081 	} else {
1082 	    /*
1083 	     * F -> T
1084 	     */
1085 	    CondPushBack(o);
1086 	}
1087     }
1088     return (l);
1089 }
1090 
1091 /*-
1092  *-----------------------------------------------------------------------
1093  * CondE --
1094  *	Main expression production.
1095  *	    E -> F || E | F
1096  *
1097  * Results:
1098  *	TOK_TRUE, TOK_FALSE or TOK_ERROR.
1099  *
1100  * Side Effects:
1101  *	Tokens are, of course, consumed.
1102  *
1103  *-----------------------------------------------------------------------
1104  */
1105 static Token
1106 CondE(Boolean doEval)
1107 {
1108     Token   l, o;
1109 
1110     l = CondF(doEval);
1111     if (l != TOK_ERROR) {
1112 	o = CondToken(doEval);
1113 
1114 	if (o == TOK_OR) {
1115 	    /*
1116 	     * E -> F || E
1117 	     *
1118 	     * A similar thing occurs for ||, except that here we make sure
1119 	     * the l.h.s. is TOK_FALSE before we bother to evaluate the r.h.s.
1120 	     * Once again, if l is TOK_FALSE, the result is the r.h.s. and once
1121 	     * again if l is TOK_TRUE, we parse the r.h.s. to throw it away.
1122 	     */
1123 	    if (l == TOK_FALSE) {
1124 		l = CondE(doEval);
1125 	    } else {
1126 		(void)CondE(FALSE);
1127 	    }
1128 	} else {
1129 	    /*
1130 	     * E -> F
1131 	     */
1132 	    CondPushBack(o);
1133 	}
1134     }
1135     return (l);
1136 }
1137 
1138 /*-
1139  *-----------------------------------------------------------------------
1140  * Cond_EvalExpression --
1141  *	Evaluate an expression in the passed line. The expression
1142  *	consists of &&, ||, !, make(target), defined(variable)
1143  *	and parenthetical groupings thereof.
1144  *
1145  * Results:
1146  *	COND_PARSE	if the condition was valid grammatically
1147  *	COND_INVALID  	if not a valid conditional.
1148  *
1149  *	(*value) is set to the boolean value of the condition
1150  *
1151  * Side Effects:
1152  *	None.
1153  *
1154  *-----------------------------------------------------------------------
1155  */
1156 int
1157 Cond_EvalExpression(const struct If *info, char *line, Boolean *value, int eprint, Boolean strictLHS)
1158 {
1159     static const struct If *dflt_info;
1160     const struct If *sv_if_info = if_info;
1161     char *sv_condExpr = condExpr;
1162     Token sv_condPushBack = condPushBack;
1163     int rval;
1164 
1165     lhsStrict = strictLHS;
1166 
1167     while (*line == ' ' || *line == '\t')
1168 	line++;
1169 
1170     if (info == NULL && (info = dflt_info) == NULL) {
1171 	/* Scan for the entry for .if - it can't be first */
1172 	for (info = ifs; ; info++)
1173 	    if (info->form[0] == 0)
1174 		break;
1175 	dflt_info = info;
1176     }
1177 
1178     if_info = info != NULL ? info : ifs + 4;
1179     condExpr = line;
1180     condPushBack = TOK_NONE;
1181 
1182     rval = do_Cond_EvalExpression(value);
1183 
1184     if (rval == COND_INVALID && eprint)
1185 	Parse_Error(PARSE_FATAL, "Malformed conditional (%s)", line);
1186 
1187     if_info = sv_if_info;
1188     condExpr = sv_condExpr;
1189     condPushBack = sv_condPushBack;
1190 
1191     return rval;
1192 }
1193 
1194 static int
1195 do_Cond_EvalExpression(Boolean *value)
1196 {
1197 
1198     switch (CondE(TRUE)) {
1199     case TOK_TRUE:
1200 	if (CondToken(TRUE) == TOK_EOF) {
1201 	    *value = TRUE;
1202 	    return COND_PARSE;
1203 	}
1204 	break;
1205     case TOK_FALSE:
1206 	if (CondToken(TRUE) == TOK_EOF) {
1207 	    *value = FALSE;
1208 	    return COND_PARSE;
1209 	}
1210 	break;
1211     default:
1212     case TOK_ERROR:
1213 	break;
1214     }
1215 
1216     return COND_INVALID;
1217 }
1218 
1219 
1220 /*-
1221  *-----------------------------------------------------------------------
1222  * Cond_Eval --
1223  *	Evaluate the conditional in the passed line. The line
1224  *	looks like this:
1225  *	    .<cond-type> <expr>
1226  *	where <cond-type> is any of if, ifmake, ifnmake, ifdef,
1227  *	ifndef, elif, elifmake, elifnmake, elifdef, elifndef
1228  *	and <expr> consists of &&, ||, !, make(target), defined(variable)
1229  *	and parenthetical groupings thereof.
1230  *
1231  * Input:
1232  *	line		Line to parse
1233  *
1234  * Results:
1235  *	COND_PARSE	if should parse lines after the conditional
1236  *	COND_SKIP	if should skip lines after the conditional
1237  *	COND_INVALID  	if not a valid conditional.
1238  *
1239  * Side Effects:
1240  *	None.
1241  *
1242  * Note that the states IF_ACTIVE and ELSE_ACTIVE are only different in order
1243  * to detect splurious .else lines (as are SKIP_TO_ELSE and SKIP_TO_ENDIF)
1244  * otherwise .else could be treated as '.elif 1'.
1245  *
1246  *-----------------------------------------------------------------------
1247  */
1248 int
1249 Cond_Eval(char *line)
1250 {
1251 #define	    MAXIF      128	/* maximum depth of .if'ing */
1252 #define	    MAXIF_BUMP  32	/* how much to grow by */
1253     enum if_states {
1254 	IF_ACTIVE,		/* .if or .elif part active */
1255 	ELSE_ACTIVE,		/* .else part active */
1256 	SEARCH_FOR_ELIF,	/* searching for .elif/else to execute */
1257 	SKIP_TO_ELSE,           /* has been true, but not seen '.else' */
1258 	SKIP_TO_ENDIF		/* nothing else to execute */
1259     };
1260     static enum if_states *cond_state = NULL;
1261     static unsigned int max_if_depth = MAXIF;
1262 
1263     const struct If *ifp;
1264     Boolean 	    isElif;
1265     Boolean 	    value;
1266     int	    	    level;  	/* Level at which to report errors. */
1267     enum if_states  state;
1268 
1269     level = PARSE_FATAL;
1270     if (!cond_state) {
1271 	cond_state = bmake_malloc(max_if_depth * sizeof(*cond_state));
1272 	cond_state[0] = IF_ACTIVE;
1273     }
1274     /* skip leading character (the '.') and any whitespace */
1275     for (line++; *line == ' ' || *line == '\t'; line++)
1276 	continue;
1277 
1278     /* Find what type of if we're dealing with.  */
1279     if (line[0] == 'e') {
1280 	if (line[1] != 'l') {
1281 	    if (!istoken(line + 1, "ndif", 4))
1282 		return COND_INVALID;
1283 	    /* End of conditional section */
1284 	    if (cond_depth == cond_min_depth) {
1285 		Parse_Error(level, "if-less endif");
1286 		return COND_PARSE;
1287 	    }
1288 	    /* Return state for previous conditional */
1289 	    cond_depth--;
1290 	    return cond_state[cond_depth] <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1291 	}
1292 
1293 	/* Quite likely this is 'else' or 'elif' */
1294 	line += 2;
1295 	if (istoken(line, "se", 2)) {
1296 	    /* It is else... */
1297 	    if (cond_depth == cond_min_depth) {
1298 		Parse_Error(level, "if-less else");
1299 		return COND_PARSE;
1300 	    }
1301 
1302 	    state = cond_state[cond_depth];
1303 	    switch (state) {
1304 	    case SEARCH_FOR_ELIF:
1305 		state = ELSE_ACTIVE;
1306 		break;
1307 	    case ELSE_ACTIVE:
1308 	    case SKIP_TO_ENDIF:
1309 		Parse_Error(PARSE_WARNING, "extra else");
1310 		/* FALLTHROUGH */
1311 	    default:
1312 	    case IF_ACTIVE:
1313 	    case SKIP_TO_ELSE:
1314 		state = SKIP_TO_ENDIF;
1315 		break;
1316 	    }
1317 	    cond_state[cond_depth] = state;
1318 	    return state <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1319 	}
1320 	/* Assume for now it is an elif */
1321 	isElif = TRUE;
1322     } else
1323 	isElif = FALSE;
1324 
1325     if (line[0] != 'i' || line[1] != 'f')
1326 	/* Not an ifxxx or elifxxx line */
1327 	return COND_INVALID;
1328 
1329     /*
1330      * Figure out what sort of conditional it is -- what its default
1331      * function is, etc. -- by looking in the table of valid "ifs"
1332      */
1333     line += 2;
1334     for (ifp = ifs; ; ifp++) {
1335 	if (ifp->form == NULL)
1336 	    return COND_INVALID;
1337 	if (istoken(ifp->form, line, ifp->formlen)) {
1338 	    line += ifp->formlen;
1339 	    break;
1340 	}
1341     }
1342 
1343     /* Now we know what sort of 'if' it is... */
1344 
1345     if (isElif) {
1346 	if (cond_depth == cond_min_depth) {
1347 	    Parse_Error(level, "if-less elif");
1348 	    return COND_PARSE;
1349 	}
1350 	state = cond_state[cond_depth];
1351 	if (state == SKIP_TO_ENDIF || state == ELSE_ACTIVE) {
1352 	    Parse_Error(PARSE_WARNING, "extra elif");
1353 	    cond_state[cond_depth] = SKIP_TO_ENDIF;
1354 	    return COND_SKIP;
1355 	}
1356 	if (state != SEARCH_FOR_ELIF) {
1357 	    /* Either just finished the 'true' block, or already SKIP_TO_ELSE */
1358 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1359 	    return COND_SKIP;
1360 	}
1361     } else {
1362 	/* Normal .if */
1363 	if (cond_depth + 1 >= max_if_depth) {
1364 	    /*
1365 	     * This is rare, but not impossible.
1366 	     * In meta mode, dirdeps.mk (only runs at level 0)
1367 	     * can need more than the default.
1368 	     */
1369 	    max_if_depth += MAXIF_BUMP;
1370 	    cond_state = bmake_realloc(cond_state, max_if_depth *
1371 		sizeof(*cond_state));
1372 	}
1373 	state = cond_state[cond_depth];
1374 	cond_depth++;
1375 	if (state > ELSE_ACTIVE) {
1376 	    /* If we aren't parsing the data, treat as always false */
1377 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1378 	    return COND_SKIP;
1379 	}
1380     }
1381 
1382     /* And evaluate the conditional expresssion */
1383     if (Cond_EvalExpression(ifp, line, &value, 1, TRUE) == COND_INVALID) {
1384 	/* Syntax error in conditional, error message already output. */
1385 	/* Skip everything to matching .endif */
1386 	cond_state[cond_depth] = SKIP_TO_ELSE;
1387 	return COND_SKIP;
1388     }
1389 
1390     if (!value) {
1391 	cond_state[cond_depth] = SEARCH_FOR_ELIF;
1392 	return COND_SKIP;
1393     }
1394     cond_state[cond_depth] = IF_ACTIVE;
1395     return COND_PARSE;
1396 }
1397 
1398 
1399 
1400 /*-
1401  *-----------------------------------------------------------------------
1402  * Cond_End --
1403  *	Make sure everything's clean at the end of a makefile.
1404  *
1405  * Results:
1406  *	None.
1407  *
1408  * Side Effects:
1409  *	Parse_Error will be called if open conditionals are around.
1410  *
1411  *-----------------------------------------------------------------------
1412  */
1413 void
1414 Cond_restore_depth(unsigned int saved_depth)
1415 {
1416     int open_conds = cond_depth - cond_min_depth;
1417 
1418     if (open_conds != 0 || saved_depth > cond_depth) {
1419 	Parse_Error(PARSE_FATAL, "%d open conditional%s", open_conds,
1420 		    open_conds == 1 ? "" : "s");
1421 	cond_depth = cond_min_depth;
1422     }
1423 
1424     cond_min_depth = saved_depth;
1425 }
1426 
1427 unsigned int
1428 Cond_save_depth(void)
1429 {
1430     int depth = cond_min_depth;
1431 
1432     cond_min_depth = cond_depth;
1433     return depth;
1434 }
1435