xref: /freebsd/contrib/bmake/cond.c (revision 15c433351f54e7cd5bec8d36c8e89e6a7fa55b26)
1 /*	$NetBSD: cond.c,v 1.71 2015/12/02 00:28:24 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 1.71 2015/12/02 00:28:24 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 1.71 2015/12/02 00:28:24 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, 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     if (!*str) {
494 	*value = (double)0;
495 	return TRUE;
496     }
497     l_val = strtoul(str, &eptr, str[1] == 'x' ? 16 : 10);
498     ech = *eptr;
499     if (ech == 0 && errno != ERANGE) {
500 	d_val = str[0] == '-' ? -(double)-l_val : (double)l_val;
501     } else {
502 	if (ech != 0 && ech != '.' && ech != 'e' && ech != 'E')
503 	    return FALSE;
504 	d_val = strtod(str, &eptr);
505 	if (*eptr)
506 	    return FALSE;
507     }
508 
509     *value = d_val;
510     return TRUE;
511 }
512 
513 /*-
514  *-----------------------------------------------------------------------
515  * CondGetString --
516  *	Get a string from a variable reference or an optionally quoted
517  *	string.  This is called for the lhs and rhs of string compares.
518  *
519  * Results:
520  *	Sets freeIt if needed,
521  *	Sets quoted if string was quoted,
522  *	Returns NULL on error,
523  *	else returns string - absent any quotes.
524  *
525  * Side Effects:
526  *	Moves condExpr to end of this token.
527  *
528  *
529  *-----------------------------------------------------------------------
530  */
531 /* coverity:[+alloc : arg-*2] */
532 static char *
533 CondGetString(Boolean doEval, Boolean *quoted, void **freeIt, Boolean strictLHS)
534 {
535     Buffer buf;
536     char *cp;
537     char *str;
538     int	len;
539     int qt;
540     char *start;
541 
542     Buf_Init(&buf, 0);
543     str = NULL;
544     *freeIt = NULL;
545     *quoted = qt = *condExpr == '"' ? 1 : 0;
546     if (qt)
547 	condExpr++;
548     for (start = condExpr; *condExpr && str == NULL; condExpr++) {
549 	switch (*condExpr) {
550 	case '\\':
551 	    if (condExpr[1] != '\0') {
552 		condExpr++;
553 		Buf_AddByte(&buf, *condExpr);
554 	    }
555 	    break;
556 	case '"':
557 	    if (qt) {
558 		condExpr++;		/* we don't want the quotes */
559 		goto got_str;
560 	    } else
561 		Buf_AddByte(&buf, *condExpr); /* likely? */
562 	    break;
563 	case ')':
564 	case '!':
565 	case '=':
566 	case '>':
567 	case '<':
568 	case ' ':
569 	case '\t':
570 	    if (!qt)
571 		goto got_str;
572 	    else
573 		Buf_AddByte(&buf, *condExpr);
574 	    break;
575 	case '$':
576 	    /* if we are in quotes, then an undefined variable is ok */
577 	    str = Var_Parse(condExpr, VAR_CMD, (qt ? 0 : doEval),
578 			    TRUE, &len, freeIt);
579 	    if (str == var_Error) {
580 		if (*freeIt) {
581 		    free(*freeIt);
582 		    *freeIt = NULL;
583 		}
584 		/*
585 		 * Even if !doEval, we still report syntax errors, which
586 		 * is what getting var_Error back with !doEval means.
587 		 */
588 		str = NULL;
589 		goto cleanup;
590 	    }
591 	    condExpr += len;
592 	    /*
593 	     * If the '$' 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 (rhsQuoted || lhsQuoted) {
740 do_string_compare:
741 	if (((*op != '!') && (*op != '=')) || (op[1] != '=')) {
742 	    Parse_Error(PARSE_WARNING,
743     "String comparison operator should be either == or !=");
744 	    goto done;
745 	}
746 
747 	if (DEBUG(COND)) {
748 	    fprintf(debug_file, "lhs = \"%s\", rhs = \"%s\", op = %.2s\n",
749 		   lhs, rhs, op);
750 	}
751 	/*
752 	 * Null-terminate rhs and perform the comparison.
753 	 * t is set to the result.
754 	 */
755 	if (*op == '=') {
756 	    t = strcmp(lhs, rhs) == 0;
757 	} else {
758 	    t = strcmp(lhs, rhs) != 0;
759 	}
760     } else {
761 	/*
762 	 * rhs is either a float or an integer. Convert both the
763 	 * lhs and the rhs to a double and compare the two.
764 	 */
765 
766 	if (!CondCvtArg(lhs, &left) || !CondCvtArg(rhs, &right))
767 	    goto do_string_compare;
768 
769 	if (DEBUG(COND)) {
770 	    fprintf(debug_file, "left = %f, right = %f, op = %.2s\n", left,
771 		   right, op);
772 	}
773 	switch(op[0]) {
774 	case '!':
775 	    if (op[1] != '=') {
776 		Parse_Error(PARSE_WARNING,
777 			    "Unknown operator");
778 		goto done;
779 	    }
780 	    t = (left != right);
781 	    break;
782 	case '=':
783 	    if (op[1] != '=') {
784 		Parse_Error(PARSE_WARNING,
785 			    "Unknown operator");
786 		goto done;
787 	    }
788 	    t = (left == right);
789 	    break;
790 	case '<':
791 	    if (op[1] == '=') {
792 		t = (left <= right);
793 	    } else {
794 		t = (left < right);
795 	    }
796 	    break;
797 	case '>':
798 	    if (op[1] == '=') {
799 		t = (left >= right);
800 	    } else {
801 		t = (left > right);
802 	    }
803 	    break;
804 	}
805     }
806 
807 done:
808     if (lhsFree)
809 	free(lhsFree);
810     if (rhsFree)
811 	free(rhsFree);
812     return t;
813 }
814 
815 static int
816 get_mpt_arg(char **linePtr, char **argPtr, const char *func MAKE_ATTR_UNUSED)
817 {
818     /*
819      * Use Var_Parse to parse the spec in parens and return
820      * TOK_TRUE if the resulting string is empty.
821      */
822     int	    length;
823     void    *freeIt;
824     char    *val;
825     char    *cp = *linePtr;
826 
827     /* We do all the work here and return the result as the length */
828     *argPtr = NULL;
829 
830     val = Var_Parse(cp - 1, VAR_CMD, FALSE, TRUE, &length, &freeIt);
831     /*
832      * Advance *linePtr to beyond the closing ). Note that
833      * we subtract one because 'length' is calculated from 'cp - 1'.
834      */
835     *linePtr = cp - 1 + length;
836 
837     if (val == var_Error) {
838 	free(freeIt);
839 	return -1;
840     }
841 
842     /* A variable is empty when it just contains spaces... 4/15/92, christos */
843     while (isspace(*(unsigned char *)val))
844 	val++;
845 
846     /*
847      * For consistency with the other functions we can't generate the
848      * true/false here.
849      */
850     length = *val ? 2 : 1;
851     if (freeIt)
852 	free(freeIt);
853     return length;
854 }
855 
856 static Boolean
857 CondDoEmpty(int arglen, const char *arg MAKE_ATTR_UNUSED)
858 {
859     return arglen == 1;
860 }
861 
862 static Token
863 compare_function(Boolean doEval)
864 {
865     static const struct fn_def {
866 	const char  *fn_name;
867 	int         fn_name_len;
868         int         (*fn_getarg)(char **, char **, const char *);
869 	Boolean     (*fn_proc)(int, const char *);
870     } fn_defs[] = {
871 	{ "defined",   7, CondGetArg, CondDoDefined },
872 	{ "make",      4, CondGetArg, CondDoMake },
873 	{ "exists",    6, CondGetArg, CondDoExists },
874 	{ "empty",     5, get_mpt_arg, CondDoEmpty },
875 	{ "target",    6, CondGetArg, CondDoTarget },
876 	{ "commands",  8, CondGetArg, CondDoCommands },
877 	{ NULL,        0, NULL, NULL },
878     };
879     const struct fn_def *fn_def;
880     Token	t;
881     char	*arg = NULL;
882     int	arglen;
883     char *cp = condExpr;
884     char *cp1;
885 
886     for (fn_def = fn_defs; fn_def->fn_name != NULL; fn_def++) {
887 	if (!istoken(cp, fn_def->fn_name, fn_def->fn_name_len))
888 	    continue;
889 	cp += fn_def->fn_name_len;
890 	/* There can only be whitespace before the '(' */
891 	while (isspace(*(unsigned char *)cp))
892 	    cp++;
893 	if (*cp != '(')
894 	    break;
895 
896 	arglen = fn_def->fn_getarg(&cp, &arg, fn_def->fn_name);
897 	if (arglen <= 0) {
898 	    condExpr = cp;
899 	    return arglen < 0 ? TOK_ERROR : TOK_FALSE;
900 	}
901 	/* Evaluate the argument using the required function. */
902 	t = !doEval || fn_def->fn_proc(arglen, arg);
903 	if (arg)
904 	    free(arg);
905 	condExpr = cp;
906 	return t;
907     }
908 
909     /* Push anything numeric through the compare expression */
910     cp = condExpr;
911     if (isdigit((unsigned char)cp[0]) || strchr("+-", cp[0]))
912 	return compare_expression(doEval);
913 
914     /*
915      * Most likely we have a naked token to apply the default function to.
916      * However ".if a == b" gets here when the "a" is unquoted and doesn't
917      * start with a '$'. This surprises people.
918      * If what follows the function argument is a '=' or '!' then the syntax
919      * would be invalid if we did "defined(a)" - so instead treat as an
920      * expression.
921      */
922     arglen = CondGetArg(&cp, &arg, NULL);
923     for (cp1 = cp; isspace(*(unsigned char *)cp1); cp1++)
924 	continue;
925     if (*cp1 == '=' || *cp1 == '!')
926 	return compare_expression(doEval);
927     condExpr = cp;
928 
929     /*
930      * Evaluate the argument using the default function.
931      * This path always treats .if as .ifdef. To get here the character
932      * after .if must have been taken literally, so the argument cannot
933      * be empty - even if it contained a variable expansion.
934      */
935     t = !doEval || if_info->defProc(arglen, arg) != if_info->doNot;
936     if (arg)
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 
1182     if_info = info != NULL ? info : ifs + 4;
1183     condExpr = line;
1184     condPushBack = TOK_NONE;
1185 
1186     rval = do_Cond_EvalExpression(value);
1187 
1188     if (rval == COND_INVALID && eprint)
1189 	Parse_Error(PARSE_FATAL, "Malformed conditional (%s)", line);
1190 
1191     if_info = sv_if_info;
1192     condExpr = sv_condExpr;
1193     condPushBack = sv_condPushBack;
1194 
1195     return rval;
1196 }
1197 
1198 static int
1199 do_Cond_EvalExpression(Boolean *value)
1200 {
1201 
1202     switch (CondE(TRUE)) {
1203     case TOK_TRUE:
1204 	if (CondToken(TRUE) == TOK_EOF) {
1205 	    *value = TRUE;
1206 	    return COND_PARSE;
1207 	}
1208 	break;
1209     case TOK_FALSE:
1210 	if (CondToken(TRUE) == TOK_EOF) {
1211 	    *value = FALSE;
1212 	    return COND_PARSE;
1213 	}
1214 	break;
1215     default:
1216     case TOK_ERROR:
1217 	break;
1218     }
1219 
1220     return COND_INVALID;
1221 }
1222 
1223 
1224 /*-
1225  *-----------------------------------------------------------------------
1226  * Cond_Eval --
1227  *	Evaluate the conditional in the passed line. The line
1228  *	looks like this:
1229  *	    .<cond-type> <expr>
1230  *	where <cond-type> is any of if, ifmake, ifnmake, ifdef,
1231  *	ifndef, elif, elifmake, elifnmake, elifdef, elifndef
1232  *	and <expr> consists of &&, ||, !, make(target), defined(variable)
1233  *	and parenthetical groupings thereof.
1234  *
1235  * Input:
1236  *	line		Line to parse
1237  *
1238  * Results:
1239  *	COND_PARSE	if should parse lines after the conditional
1240  *	COND_SKIP	if should skip lines after the conditional
1241  *	COND_INVALID  	if not a valid conditional.
1242  *
1243  * Side Effects:
1244  *	None.
1245  *
1246  * Note that the states IF_ACTIVE and ELSE_ACTIVE are only different in order
1247  * to detect splurious .else lines (as are SKIP_TO_ELSE and SKIP_TO_ENDIF)
1248  * otherwise .else could be treated as '.elif 1'.
1249  *
1250  *-----------------------------------------------------------------------
1251  */
1252 int
1253 Cond_Eval(char *line)
1254 {
1255 #define	    MAXIF      128	/* maximum depth of .if'ing */
1256 #define	    MAXIF_BUMP  32	/* how much to grow by */
1257     enum if_states {
1258 	IF_ACTIVE,		/* .if or .elif part active */
1259 	ELSE_ACTIVE,		/* .else part active */
1260 	SEARCH_FOR_ELIF,	/* searching for .elif/else to execute */
1261 	SKIP_TO_ELSE,           /* has been true, but not seen '.else' */
1262 	SKIP_TO_ENDIF		/* nothing else to execute */
1263     };
1264     static enum if_states *cond_state = NULL;
1265     static unsigned int max_if_depth = MAXIF;
1266 
1267     const struct If *ifp;
1268     Boolean 	    isElif;
1269     Boolean 	    value;
1270     int	    	    level;  	/* Level at which to report errors. */
1271     enum if_states  state;
1272 
1273     level = PARSE_FATAL;
1274     if (!cond_state) {
1275 	cond_state = bmake_malloc(max_if_depth * sizeof(*cond_state));
1276 	cond_state[0] = IF_ACTIVE;
1277     }
1278     /* skip leading character (the '.') and any whitespace */
1279     for (line++; *line == ' ' || *line == '\t'; line++)
1280 	continue;
1281 
1282     /* Find what type of if we're dealing with.  */
1283     if (line[0] == 'e') {
1284 	if (line[1] != 'l') {
1285 	    if (!istoken(line + 1, "ndif", 4))
1286 		return COND_INVALID;
1287 	    /* End of conditional section */
1288 	    if (cond_depth == cond_min_depth) {
1289 		Parse_Error(level, "if-less endif");
1290 		return COND_PARSE;
1291 	    }
1292 	    /* Return state for previous conditional */
1293 	    cond_depth--;
1294 	    return cond_state[cond_depth] <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1295 	}
1296 
1297 	/* Quite likely this is 'else' or 'elif' */
1298 	line += 2;
1299 	if (istoken(line, "se", 2)) {
1300 	    /* It is else... */
1301 	    if (cond_depth == cond_min_depth) {
1302 		Parse_Error(level, "if-less else");
1303 		return COND_PARSE;
1304 	    }
1305 
1306 	    state = cond_state[cond_depth];
1307 	    switch (state) {
1308 	    case SEARCH_FOR_ELIF:
1309 		state = ELSE_ACTIVE;
1310 		break;
1311 	    case ELSE_ACTIVE:
1312 	    case SKIP_TO_ENDIF:
1313 		Parse_Error(PARSE_WARNING, "extra else");
1314 		/* FALLTHROUGH */
1315 	    default:
1316 	    case IF_ACTIVE:
1317 	    case SKIP_TO_ELSE:
1318 		state = SKIP_TO_ENDIF;
1319 		break;
1320 	    }
1321 	    cond_state[cond_depth] = state;
1322 	    return state <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1323 	}
1324 	/* Assume for now it is an elif */
1325 	isElif = TRUE;
1326     } else
1327 	isElif = FALSE;
1328 
1329     if (line[0] != 'i' || line[1] != 'f')
1330 	/* Not an ifxxx or elifxxx line */
1331 	return COND_INVALID;
1332 
1333     /*
1334      * Figure out what sort of conditional it is -- what its default
1335      * function is, etc. -- by looking in the table of valid "ifs"
1336      */
1337     line += 2;
1338     for (ifp = ifs; ; ifp++) {
1339 	if (ifp->form == NULL)
1340 	    return COND_INVALID;
1341 	if (istoken(ifp->form, line, ifp->formlen)) {
1342 	    line += ifp->formlen;
1343 	    break;
1344 	}
1345     }
1346 
1347     /* Now we know what sort of 'if' it is... */
1348 
1349     if (isElif) {
1350 	if (cond_depth == cond_min_depth) {
1351 	    Parse_Error(level, "if-less elif");
1352 	    return COND_PARSE;
1353 	}
1354 	state = cond_state[cond_depth];
1355 	if (state == SKIP_TO_ENDIF || state == ELSE_ACTIVE) {
1356 	    Parse_Error(PARSE_WARNING, "extra elif");
1357 	    cond_state[cond_depth] = SKIP_TO_ENDIF;
1358 	    return COND_SKIP;
1359 	}
1360 	if (state != SEARCH_FOR_ELIF) {
1361 	    /* Either just finished the 'true' block, or already SKIP_TO_ELSE */
1362 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1363 	    return COND_SKIP;
1364 	}
1365     } else {
1366 	/* Normal .if */
1367 	if (cond_depth + 1 >= max_if_depth) {
1368 	    /*
1369 	     * This is rare, but not impossible.
1370 	     * In meta mode, dirdeps.mk (only runs at level 0)
1371 	     * can need more than the default.
1372 	     */
1373 	    max_if_depth += MAXIF_BUMP;
1374 	    cond_state = bmake_realloc(cond_state, max_if_depth *
1375 		sizeof(*cond_state));
1376 	}
1377 	state = cond_state[cond_depth];
1378 	cond_depth++;
1379 	if (state > ELSE_ACTIVE) {
1380 	    /* If we aren't parsing the data, treat as always false */
1381 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1382 	    return COND_SKIP;
1383 	}
1384     }
1385 
1386     /* And evaluate the conditional expresssion */
1387     if (Cond_EvalExpression(ifp, line, &value, 1, TRUE) == COND_INVALID) {
1388 	/* Syntax error in conditional, error message already output. */
1389 	/* Skip everything to matching .endif */
1390 	cond_state[cond_depth] = SKIP_TO_ELSE;
1391 	return COND_SKIP;
1392     }
1393 
1394     if (!value) {
1395 	cond_state[cond_depth] = SEARCH_FOR_ELIF;
1396 	return COND_SKIP;
1397     }
1398     cond_state[cond_depth] = IF_ACTIVE;
1399     return COND_PARSE;
1400 }
1401 
1402 
1403 
1404 /*-
1405  *-----------------------------------------------------------------------
1406  * Cond_End --
1407  *	Make sure everything's clean at the end of a makefile.
1408  *
1409  * Results:
1410  *	None.
1411  *
1412  * Side Effects:
1413  *	Parse_Error will be called if open conditionals are around.
1414  *
1415  *-----------------------------------------------------------------------
1416  */
1417 void
1418 Cond_restore_depth(unsigned int saved_depth)
1419 {
1420     int open_conds = cond_depth - cond_min_depth;
1421 
1422     if (open_conds != 0 || saved_depth > cond_depth) {
1423 	Parse_Error(PARSE_FATAL, "%d open conditional%s", open_conds,
1424 		    open_conds == 1 ? "" : "s");
1425 	cond_depth = cond_min_depth;
1426     }
1427 
1428     cond_min_depth = saved_depth;
1429 }
1430 
1431 unsigned int
1432 Cond_save_depth(void)
1433 {
1434     int depth = cond_min_depth;
1435 
1436     cond_min_depth = cond_depth;
1437     return depth;
1438 }
1439