xref: /netbsd-src/usr.bin/make/cond.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: cond.c,v 1.24 2004/05/07 00:04:38 ross 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 1.24 2004/05/07 00:04:38 ross 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 1.24 2004/05/07 00:04:38 ross 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 
96 #include    "make.h"
97 #include    "hash.h"
98 #include    "dir.h"
99 #include    "buf.h"
100 
101 /*
102  * The parsing of conditional expressions is based on this grammar:
103  *	E -> F || E
104  *	E -> F
105  *	F -> T && F
106  *	F -> T
107  *	T -> defined(variable)
108  *	T -> make(target)
109  *	T -> exists(file)
110  *	T -> empty(varspec)
111  *	T -> target(name)
112  *	T -> commands(name)
113  *	T -> symbol
114  *	T -> $(varspec) op value
115  *	T -> $(varspec) == "string"
116  *	T -> $(varspec) != "string"
117  *	T -> "string"
118  *	T -> ( E )
119  *	T -> ! T
120  *	op -> == | != | > | < | >= | <=
121  *
122  * 'symbol' is some other symbol to which the default function (condDefProc)
123  * is applied.
124  *
125  * Tokens are scanned from the 'condExpr' string. The scanner (CondToken)
126  * will return And for '&' and '&&', Or for '|' and '||', Not for '!',
127  * LParen for '(', RParen for ')' and will evaluate the other terminal
128  * symbols, using either the default function or the function given in the
129  * terminal, and return the result as either True or False.
130  *
131  * All Non-Terminal functions (CondE, CondF and CondT) return Err on error.
132  */
133 typedef enum {
134     And, Or, Not, True, False, LParen, RParen, EndOfFile, None, Err
135 } Token;
136 
137 /*-
138  * Structures to handle elegantly the different forms of #if's. The
139  * last two fields are stored in condInvert and condDefProc, respectively.
140  */
141 static void CondPushBack(Token);
142 static int CondGetArg(char **, char **, const char *, Boolean);
143 static Boolean CondDoDefined(int, char *);
144 static int CondStrMatch(ClientData, ClientData);
145 static Boolean CondDoMake(int, char *);
146 static Boolean CondDoExists(int, char *);
147 static Boolean CondDoTarget(int, char *);
148 static Boolean CondDoCommands(int, char *);
149 static char * CondCvtArg(char *, double *);
150 static Token CondToken(Boolean);
151 static Token CondT(Boolean);
152 static Token CondF(Boolean);
153 static Token CondE(Boolean);
154 
155 static struct If {
156     const char	*form;	      /* Form of if */
157     int		formlen;      /* Length of form */
158     Boolean	doNot;	      /* TRUE if default function should be negated */
159     Boolean	(*defProc)(int, char *); /* Default function to apply */
160 } ifs[] = {
161     { "ifdef",	  5,	  FALSE,  CondDoDefined },
162     { "ifndef",	  6,	  TRUE,	  CondDoDefined },
163     { "ifmake",	  6,	  FALSE,  CondDoMake },
164     { "ifnmake",  7,	  TRUE,	  CondDoMake },
165     { "if",	  2,	  FALSE,  CondDoDefined },
166     { NULL,	  0,	  FALSE,  NULL }
167 };
168 
169 static Boolean	  condInvert;	    	/* Invert the default function */
170 static Boolean	  (*condDefProc)(int, char *);	/* Default function to apply */
171 static char 	  *condExpr;	    	/* The expression to parse */
172 static Token	  condPushBack=None;	/* Single push-back token used in
173 					 * parsing */
174 
175 #define	MAXIF		64	  /* greatest depth of #if'ing */
176 
177 static Boolean	  finalElse[MAXIF+1][MAXIF+1]; /* Seen final else (stack) */
178 static Boolean	  condStack[MAXIF]; 	/* Stack of conditionals's values */
179 static int  	  condTop = MAXIF;  	/* Top-most conditional */
180 static int  	  skipIfLevel=0;    	/* Depth of skipped conditionals */
181 static Boolean	  skipLine = FALSE; 	/* Whether the parse module is skipping
182 					 * lines */
183 
184 /*-
185  *-----------------------------------------------------------------------
186  * CondPushBack --
187  *	Push back the most recent token read. We only need one level of
188  *	this, so the thing is just stored in 'condPushback'.
189  *
190  * Input:
191  *	t		Token to push back into the "stream"
192  *
193  * Results:
194  *	None.
195  *
196  * Side Effects:
197  *	condPushback is overwritten.
198  *
199  *-----------------------------------------------------------------------
200  */
201 static void
202 CondPushBack(Token t)
203 {
204     condPushBack = t;
205 }
206 
207 /*-
208  *-----------------------------------------------------------------------
209  * CondGetArg --
210  *	Find the argument of a built-in function.
211  *
212  * Input:
213  *	parens		TRUE if arg should be bounded by parens
214  *
215  * Results:
216  *	The length of the argument and the address of the argument.
217  *
218  * Side Effects:
219  *	The pointer is set to point to the closing parenthesis of the
220  *	function call.
221  *
222  *-----------------------------------------------------------------------
223  */
224 static int
225 CondGetArg(char **linePtr, char **argPtr, const char *func, Boolean parens)
226 {
227     char	  *cp;
228     int	    	  argLen;
229     Buffer	  buf;
230 
231     cp = *linePtr;
232     if (parens) {
233 	while (*cp != '(' && *cp != '\0') {
234 	    cp++;
235 	}
236 	if (*cp == '(') {
237 	    cp++;
238 	}
239     }
240 
241     if (*cp == '\0') {
242 	/*
243 	 * No arguments whatsoever. Because 'make' and 'defined' aren't really
244 	 * "reserved words", we don't print a message. I think this is better
245 	 * than hitting the user with a warning message every time s/he uses
246 	 * the word 'make' or 'defined' at the beginning of a symbol...
247 	 */
248 	*argPtr = cp;
249 	return (0);
250     }
251 
252     while (*cp == ' ' || *cp == '\t') {
253 	cp++;
254     }
255 
256     /*
257      * Create a buffer for the argument and start it out at 16 characters
258      * long. Why 16? Why not?
259      */
260     buf = Buf_Init(16);
261 
262     while ((strchr(" \t)&|", *cp) == (char *)NULL) && (*cp != '\0')) {
263 	if (*cp == '$') {
264 	    /*
265 	     * Parse the variable spec and install it as part of the argument
266 	     * if it's valid. We tell Var_Parse to complain on an undefined
267 	     * variable, so we don't do it too. Nor do we return an error,
268 	     * though perhaps we should...
269 	     */
270 	    char  	*cp2;
271 	    int		len;
272 	    Boolean	doFree;
273 
274 	    cp2 = Var_Parse(cp, VAR_CMD, TRUE, &len, &doFree);
275 
276 	    Buf_AddBytes(buf, strlen(cp2), (Byte *)cp2);
277 	    if (doFree) {
278 		free(cp2);
279 	    }
280 	    cp += len;
281 	} else {
282 	    Buf_AddByte(buf, (Byte)*cp);
283 	    cp++;
284 	}
285     }
286 
287     Buf_AddByte(buf, (Byte)'\0');
288     *argPtr = (char *)Buf_GetAll(buf, &argLen);
289     Buf_Destroy(buf, FALSE);
290 
291     while (*cp == ' ' || *cp == '\t') {
292 	cp++;
293     }
294     if (parens && *cp != ')') {
295 	Parse_Error (PARSE_WARNING, "Missing closing parenthesis for %s()",
296 		     func);
297 	return (0);
298     } else if (parens) {
299 	/*
300 	 * Advance pointer past close parenthesis.
301 	 */
302 	cp++;
303     }
304 
305     *linePtr = cp;
306     return (argLen);
307 }
308 
309 /*-
310  *-----------------------------------------------------------------------
311  * CondDoDefined --
312  *	Handle the 'defined' function for conditionals.
313  *
314  * Results:
315  *	TRUE if the given variable is defined.
316  *
317  * Side Effects:
318  *	None.
319  *
320  *-----------------------------------------------------------------------
321  */
322 static Boolean
323 CondDoDefined(int argLen, char *arg)
324 {
325     char    savec = arg[argLen];
326     char    *p1;
327     Boolean result;
328 
329     arg[argLen] = '\0';
330     if (Var_Value (arg, VAR_CMD, &p1) != (char *)NULL) {
331 	result = TRUE;
332     } else {
333 	result = FALSE;
334     }
335     if (p1)
336 	free(p1);
337     arg[argLen] = savec;
338     return (result);
339 }
340 
341 /*-
342  *-----------------------------------------------------------------------
343  * CondStrMatch --
344  *	Front-end for Str_Match so it returns 0 on match and non-zero
345  *	on mismatch. Callback function for CondDoMake via Lst_Find
346  *
347  * Results:
348  *	0 if string matches pattern
349  *
350  * Side Effects:
351  *	None
352  *
353  *-----------------------------------------------------------------------
354  */
355 static int
356 CondStrMatch(ClientData string, ClientData pattern)
357 {
358     return(!Str_Match((char *) string,(char *) pattern));
359 }
360 
361 /*-
362  *-----------------------------------------------------------------------
363  * CondDoMake --
364  *	Handle the 'make' function for conditionals.
365  *
366  * Results:
367  *	TRUE if the given target is being made.
368  *
369  * Side Effects:
370  *	None.
371  *
372  *-----------------------------------------------------------------------
373  */
374 static Boolean
375 CondDoMake(int argLen, char *arg)
376 {
377     char    savec = arg[argLen];
378     Boolean result;
379 
380     arg[argLen] = '\0';
381     if (Lst_Find (create, (ClientData)arg, CondStrMatch) == NILLNODE) {
382 	result = FALSE;
383     } else {
384 	result = TRUE;
385     }
386     arg[argLen] = savec;
387     return (result);
388 }
389 
390 /*-
391  *-----------------------------------------------------------------------
392  * CondDoExists --
393  *	See if the given file exists.
394  *
395  * Results:
396  *	TRUE if the file exists and FALSE if it does not.
397  *
398  * Side Effects:
399  *	None.
400  *
401  *-----------------------------------------------------------------------
402  */
403 static Boolean
404 CondDoExists(int argLen, char *arg)
405 {
406     char    savec = arg[argLen];
407     Boolean result;
408     char    *path;
409 
410     arg[argLen] = '\0';
411     path = Dir_FindFile(arg, dirSearchPath);
412     if (path != (char *)NULL) {
413 	result = TRUE;
414 	free(path);
415     } else {
416 	result = FALSE;
417     }
418     arg[argLen] = savec;
419     return (result);
420 }
421 
422 /*-
423  *-----------------------------------------------------------------------
424  * CondDoTarget --
425  *	See if the given node exists and is an actual target.
426  *
427  * Results:
428  *	TRUE if the node exists as a target and FALSE if it does not.
429  *
430  * Side Effects:
431  *	None.
432  *
433  *-----------------------------------------------------------------------
434  */
435 static Boolean
436 CondDoTarget(int argLen, char *arg)
437 {
438     char    savec = arg[argLen];
439     Boolean result;
440     GNode   *gn;
441 
442     arg[argLen] = '\0';
443     gn = Targ_FindNode(arg, TARG_NOCREATE);
444     if ((gn != NILGNODE) && !OP_NOP(gn->type)) {
445 	result = TRUE;
446     } else {
447 	result = FALSE;
448     }
449     arg[argLen] = savec;
450     return (result);
451 }
452 
453 /*-
454  *-----------------------------------------------------------------------
455  * CondDoCommands --
456  *	See if the given node exists and is an actual target with commands
457  *	associated with it.
458  *
459  * Results:
460  *	TRUE if the node exists as a target and has commands associated with
461  *	it and FALSE if it does not.
462  *
463  * Side Effects:
464  *	None.
465  *
466  *-----------------------------------------------------------------------
467  */
468 static Boolean
469 CondDoCommands(int argLen, char *arg)
470 {
471     char    savec = arg[argLen];
472     Boolean result;
473     GNode   *gn;
474 
475     arg[argLen] = '\0';
476     gn = Targ_FindNode(arg, TARG_NOCREATE);
477     if ((gn != NILGNODE) && !OP_NOP(gn->type) && !Lst_IsEmpty(gn->commands)) {
478 	result = TRUE;
479     } else {
480 	result = FALSE;
481     }
482     arg[argLen] = savec;
483     return (result);
484 }
485 
486 /*-
487  *-----------------------------------------------------------------------
488  * CondCvtArg --
489  *	Convert the given number into a double. If the number begins
490  *	with 0x, it is interpreted as a hexadecimal integer
491  *	and converted to a double from there. All other strings just have
492  *	strtod called on them.
493  *
494  * Results:
495  *	Sets 'value' to double value of string.
496  *	Returns NULL if string was fully consumed,
497  *	else returns remaining input.
498  *
499  * Side Effects:
500  *	Can change 'value' even if string is not a valid number.
501  *
502  *
503  *-----------------------------------------------------------------------
504  */
505 static char *
506 CondCvtArg(char *str, double *value)
507 {
508     if ((*str == '0') && (str[1] == 'x')) {
509 	long i;
510 
511 	for (str += 2, i = 0; *str; str++) {
512 	    int x;
513 	    if (isdigit((unsigned char) *str))
514 		x  = *str - '0';
515 	    else if (isxdigit((unsigned char) *str))
516 		x = 10 + *str - isupper((unsigned char) *str) ? 'A' : 'a';
517 	    else
518 		break;
519 	    i = (i << 4) + x;
520 	}
521 	*value = (double) i;
522 	return *str ? str : NULL;
523     } else {
524 	char *eptr;
525 	*value = strtod(str, &eptr);
526 	return *eptr ? eptr : NULL;
527     }
528 }
529 
530 /*-
531  *-----------------------------------------------------------------------
532  * CondGetString --
533  *	Get a string from a variable reference or an optionally quoted
534  *	string.  This is called for the lhs and rhs of string compares.
535  *
536  * Results:
537  *	Sets doFree if needed,
538  *	Sets quoted if string was quoted,
539  *	Returns NULL on error,
540  *	else returns string - absent any quotes.
541  *
542  * Side Effects:
543  *	Moves condExpr to end of this token.
544  *
545  *
546  *-----------------------------------------------------------------------
547  */
548 static char *
549 CondGetString(Boolean doEval, Boolean *quoted, Boolean *doFree)
550 {
551     Buffer buf;
552     char *cp;
553     char *str;
554     int	len;
555     int qt;
556     char *start;
557 
558     buf = Buf_Init(0);
559     str = NULL;
560     *quoted = qt = *condExpr == '"' ? 1 : 0;
561     if (qt)
562 	condExpr++;
563     for (start = condExpr; *condExpr && str == NULL; condExpr++) {
564 	switch (*condExpr) {
565 	case '\\':
566 	    if (condExpr[1] != '\0') {
567 		condExpr++;
568 		Buf_AddByte(buf, (Byte)*condExpr);
569 	    }
570 	    break;
571 	case '"':
572 	    if (qt) {
573 		condExpr++;		/* we don't want the quotes */
574 		goto got_str;
575 	    } else
576 		Buf_AddByte(buf, (Byte)*condExpr); /* likely? */
577 	    break;
578 	case ')':
579 	case '!':
580 	case '=':
581 	case '>':
582 	case '<':
583 	case ' ':
584 	case '\t':
585 	    if (!qt)
586 		goto got_str;
587 	    else
588 		Buf_AddByte(buf, (Byte)*condExpr);
589 	    break;
590 	case '$':
591 	    /* if we are in quotes, then an undefined variable is ok */
592 	    str = Var_Parse(condExpr, VAR_CMD, (qt ? 0 : doEval),
593 			    &len, doFree);
594 	    if (str == var_Error) {
595 		/*
596 		 * Even if !doEval, we still report syntax errors, which
597 		 * is what getting var_Error back with !doEval means.
598 		 */
599 		str = NULL;
600 		goto cleanup;
601 	    }
602 	    condExpr += len;
603 	    /*
604 	     * If the '$' was first char (no quotes), and we are
605 	     * followed by space, the operator or end of expression,
606 	     * we are done.
607 	     */
608 	    if ((condExpr == start + len) &&
609 		(*condExpr == '\0' ||
610 		 isspace((unsigned char) *condExpr) ||
611 		 strchr("!=><)", *condExpr))) {
612 		goto cleanup;
613 	    }
614 	    /*
615 	     * Nope, we better copy str to buf
616 	     */
617 	    for (cp = str; *cp; cp++) {
618 		Buf_AddByte(buf, (Byte)*cp);
619 	    }
620 	    if (*doFree)
621 		free(str);
622 	    *doFree = FALSE;
623 	    str = NULL;			/* not finished yet */
624 	    condExpr--;			/* don't skip over next char */
625 	    break;
626 	default:
627 	    Buf_AddByte(buf, (Byte)*condExpr);
628 	    break;
629 	}
630     }
631  got_str:
632     Buf_AddByte(buf, (Byte)'\0');
633     str = (char *)Buf_GetAll(buf, NULL);
634     *doFree = TRUE;
635  cleanup:
636     Buf_Destroy(buf, FALSE);
637     return str;
638 }
639 
640 /*-
641  *-----------------------------------------------------------------------
642  * CondToken --
643  *	Return the next token from the input.
644  *
645  * Results:
646  *	A Token for the next lexical token in the stream.
647  *
648  * Side Effects:
649  *	condPushback will be set back to None if it is used.
650  *
651  *-----------------------------------------------------------------------
652  */
653 static Token
654 CondToken(Boolean doEval)
655 {
656     Token	  t;
657 
658     if (condPushBack == None) {
659 	while (*condExpr == ' ' || *condExpr == '\t') {
660 	    condExpr++;
661 	}
662 	switch (*condExpr) {
663 	    case '(':
664 		t = LParen;
665 		condExpr++;
666 		break;
667 	    case ')':
668 		t = RParen;
669 		condExpr++;
670 		break;
671 	    case '|':
672 		if (condExpr[1] == '|') {
673 		    condExpr++;
674 		}
675 		condExpr++;
676 		t = Or;
677 		break;
678 	    case '&':
679 		if (condExpr[1] == '&') {
680 		    condExpr++;
681 		}
682 		condExpr++;
683 		t = And;
684 		break;
685 	    case '!':
686 		t = Not;
687 		condExpr++;
688 		break;
689 	    case '#':
690 	    case '\n':
691 	    case '\0':
692 		t = EndOfFile;
693 		break;
694 	    case '"':
695 	    case '$': {
696 		char	*lhs;
697 		char	*rhs;
698 		char	*op;
699 		Boolean	lhsFree;
700 		Boolean	rhsFree;
701 		Boolean lhsQuoted;
702 		Boolean rhsQuoted;
703 
704 		lhsFree = rhsFree = FALSE;
705 		lhsQuoted = rhsQuoted = FALSE;
706 
707 		/*
708 		 * Parse the variable spec and skip over it, saving its
709 		 * value in lhs.
710 		 */
711 		t = Err;
712 		lhs = CondGetString(doEval, &lhsQuoted, &lhsFree);
713 		if (!lhs)
714 		    return Err;
715 		/*
716 		 * Skip whitespace to get to the operator
717 		 */
718 		while (isspace((unsigned char) *condExpr))
719 		    condExpr++;
720 
721 		/*
722 		 * Make sure the operator is a valid one. If it isn't a
723 		 * known relational operator, pretend we got a
724 		 * != 0 comparison.
725 		 */
726 		op = condExpr;
727 		switch (*condExpr) {
728 		    case '!':
729 		    case '=':
730 		    case '<':
731 		    case '>':
732 			if (condExpr[1] == '=') {
733 			    condExpr += 2;
734 			} else {
735 			    condExpr += 1;
736 			}
737 			break;
738 		    default:
739 			op = UNCONST("!=");
740 			if (lhsQuoted)
741 			    rhs = UNCONST("");
742 			else
743 			    rhs = UNCONST("0");
744 
745 			goto do_compare;
746 		}
747 		while (isspace((unsigned char) *condExpr)) {
748 		    condExpr++;
749 		}
750 		if (*condExpr == '\0') {
751 		    Parse_Error(PARSE_WARNING,
752 				"Missing right-hand-side of operator");
753 		    goto error;
754 		}
755 		rhs = CondGetString(doEval, &rhsQuoted, &rhsFree);
756 		if (!rhs)
757 		    return Err;
758 do_compare:
759 		if (rhsQuoted || lhsQuoted) {
760 do_string_compare:
761 		    if (((*op != '!') && (*op != '=')) || (op[1] != '=')) {
762 			Parse_Error(PARSE_WARNING,
763 		"String comparison operator should be either == or !=");
764 			goto error;
765 		    }
766 
767 		    if (DEBUG(COND)) {
768 			printf("lhs = \"%s\", rhs = \"%s\", op = %.2s\n",
769 			       lhs, rhs, op);
770 		    }
771 		    /*
772 		     * Null-terminate rhs and perform the comparison.
773 		     * t is set to the result.
774 		     */
775 		    if (*op == '=') {
776 			t = strcmp(lhs, rhs) ? False : True;
777 		    } else {
778 			t = strcmp(lhs, rhs) ? True : False;
779 		    }
780 		} else {
781 		    /*
782 		     * rhs is either a float or an integer. Convert both the
783 		     * lhs and the rhs to a double and compare the two.
784 		     */
785 		    double  	left, right;
786 		    char	*cp;
787 
788 		    if (CondCvtArg(lhs, &left))
789 			goto do_string_compare;
790 		    if ((cp = CondCvtArg(rhs, &right)) &&
791 			    cp == rhs)
792 			goto do_string_compare;
793 
794 		    if (DEBUG(COND)) {
795 			printf("left = %f, right = %f, op = %.2s\n", left,
796 			       right, op);
797 		    }
798 		    switch(op[0]) {
799 		    case '!':
800 			if (op[1] != '=') {
801 			    Parse_Error(PARSE_WARNING,
802 					"Unknown operator");
803 			    goto error;
804 			}
805 			t = (left != right ? True : False);
806 			break;
807 		    case '=':
808 			if (op[1] != '=') {
809 			    Parse_Error(PARSE_WARNING,
810 					"Unknown operator");
811 			    goto error;
812 			}
813 			t = (left == right ? True : False);
814 			break;
815 		    case '<':
816 			if (op[1] == '=') {
817 			    t = (left <= right ? True : False);
818 			} else {
819 			    t = (left < right ? True : False);
820 			}
821 			break;
822 		    case '>':
823 			if (op[1] == '=') {
824 			    t = (left >= right ? True : False);
825 			} else {
826 			    t = (left > right ? True : False);
827 			}
828 			break;
829 		    }
830 		}
831 error:
832 		if (lhsFree)
833 		    free(lhs);
834 		if (rhsFree)
835 		    free(rhs);
836 		break;
837 	    }
838 	    default: {
839 		Boolean (*evalProc)(int, char *);
840 		Boolean invert = FALSE;
841 		char	*arg;
842 		int	arglen;
843 
844 		if (strncmp (condExpr, "defined", 7) == 0) {
845 		    /*
846 		     * Use CondDoDefined to evaluate the argument and
847 		     * CondGetArg to extract the argument from the 'function
848 		     * call'.
849 		     */
850 		    evalProc = CondDoDefined;
851 		    condExpr += 7;
852 		    arglen = CondGetArg (&condExpr, &arg, "defined", TRUE);
853 		    if (arglen == 0) {
854 			condExpr -= 7;
855 			goto use_default;
856 		    }
857 		} else if (strncmp (condExpr, "make", 4) == 0) {
858 		    /*
859 		     * Use CondDoMake to evaluate the argument and
860 		     * CondGetArg to extract the argument from the 'function
861 		     * call'.
862 		     */
863 		    evalProc = CondDoMake;
864 		    condExpr += 4;
865 		    arglen = CondGetArg (&condExpr, &arg, "make", TRUE);
866 		    if (arglen == 0) {
867 			condExpr -= 4;
868 			goto use_default;
869 		    }
870 		} else if (strncmp (condExpr, "exists", 6) == 0) {
871 		    /*
872 		     * Use CondDoExists to evaluate the argument and
873 		     * CondGetArg to extract the argument from the
874 		     * 'function call'.
875 		     */
876 		    evalProc = CondDoExists;
877 		    condExpr += 6;
878 		    arglen = CondGetArg(&condExpr, &arg, "exists", TRUE);
879 		    if (arglen == 0) {
880 			condExpr -= 6;
881 			goto use_default;
882 		    }
883 		} else if (strncmp(condExpr, "empty", 5) == 0) {
884 		    /*
885 		     * Use Var_Parse to parse the spec in parens and return
886 		     * True if the resulting string is empty.
887 		     */
888 		    int	    length;
889 		    Boolean doFree;
890 		    char    *val;
891 
892 		    condExpr += 5;
893 
894 		    for (arglen = 0;
895 			 condExpr[arglen] != '(' && condExpr[arglen] != '\0';
896 			 arglen += 1)
897 			continue;
898 
899 		    if (condExpr[arglen] != '\0') {
900 			val = Var_Parse(&condExpr[arglen - 1], VAR_CMD,
901 					FALSE, &length, &doFree);
902 			if (val == var_Error) {
903 			    t = Err;
904 			} else {
905 			    /*
906 			     * A variable is empty when it just contains
907 			     * spaces... 4/15/92, christos
908 			     */
909 			    char *p;
910 			    for (p = val; *p && isspace((unsigned char)*p); p++)
911 				continue;
912 			    t = (*p == '\0') ? True : False;
913 			}
914 			if (doFree) {
915 			    free(val);
916 			}
917 			/*
918 			 * Advance condExpr to beyond the closing ). Note that
919 			 * we subtract one from arglen + length b/c length
920 			 * is calculated from condExpr[arglen - 1].
921 			 */
922 			condExpr += arglen + length - 1;
923 		    } else {
924 			condExpr -= 5;
925 			goto use_default;
926 		    }
927 		    break;
928 		} else if (strncmp (condExpr, "target", 6) == 0) {
929 		    /*
930 		     * Use CondDoTarget to evaluate the argument and
931 		     * CondGetArg to extract the argument from the
932 		     * 'function call'.
933 		     */
934 		    evalProc = CondDoTarget;
935 		    condExpr += 6;
936 		    arglen = CondGetArg(&condExpr, &arg, "target", TRUE);
937 		    if (arglen == 0) {
938 			condExpr -= 6;
939 			goto use_default;
940 		    }
941 		} else if (strncmp (condExpr, "commands", 8) == 0) {
942 		    /*
943 		     * Use CondDoCommands to evaluate the argument and
944 		     * CondGetArg to extract the argument from the
945 		     * 'function call'.
946 		     */
947 		    evalProc = CondDoCommands;
948 		    condExpr += 8;
949 		    arglen = CondGetArg(&condExpr, &arg, "commands", TRUE);
950 		    if (arglen == 0) {
951 			condExpr -= 8;
952 			goto use_default;
953 		    }
954 		} else {
955 		    /*
956 		     * The symbol is itself the argument to the default
957 		     * function. We advance condExpr to the end of the symbol
958 		     * by hand (the next whitespace, closing paren or
959 		     * binary operator) and set to invert the evaluation
960 		     * function if condInvert is TRUE.
961 		     */
962 		use_default:
963 		    invert = condInvert;
964 		    evalProc = condDefProc;
965 		    arglen = CondGetArg(&condExpr, &arg, "", FALSE);
966 		}
967 
968 		/*
969 		 * Evaluate the argument using the set function. If invert
970 		 * is TRUE, we invert the sense of the function.
971 		 */
972 		t = (!doEval || (* evalProc) (arglen, arg) ?
973 		     (invert ? False : True) :
974 		     (invert ? True : False));
975 		free(arg);
976 		break;
977 	    }
978 	}
979     } else {
980 	t = condPushBack;
981 	condPushBack = None;
982     }
983     return (t);
984 }
985 
986 /*-
987  *-----------------------------------------------------------------------
988  * CondT --
989  *	Parse a single term in the expression. This consists of a terminal
990  *	symbol or Not and a terminal symbol (not including the binary
991  *	operators):
992  *	    T -> defined(variable) | make(target) | exists(file) | symbol
993  *	    T -> ! T | ( E )
994  *
995  * Results:
996  *	True, False or Err.
997  *
998  * Side Effects:
999  *	Tokens are consumed.
1000  *
1001  *-----------------------------------------------------------------------
1002  */
1003 static Token
1004 CondT(Boolean doEval)
1005 {
1006     Token   t;
1007 
1008     t = CondToken(doEval);
1009 
1010     if (t == EndOfFile) {
1011 	/*
1012 	 * If we reached the end of the expression, the expression
1013 	 * is malformed...
1014 	 */
1015 	t = Err;
1016     } else if (t == LParen) {
1017 	/*
1018 	 * T -> ( E )
1019 	 */
1020 	t = CondE(doEval);
1021 	if (t != Err) {
1022 	    if (CondToken(doEval) != RParen) {
1023 		t = Err;
1024 	    }
1025 	}
1026     } else if (t == Not) {
1027 	t = CondT(doEval);
1028 	if (t == True) {
1029 	    t = False;
1030 	} else if (t == False) {
1031 	    t = True;
1032 	}
1033     }
1034     return (t);
1035 }
1036 
1037 /*-
1038  *-----------------------------------------------------------------------
1039  * CondF --
1040  *	Parse a conjunctive factor (nice name, wot?)
1041  *	    F -> T && F | T
1042  *
1043  * Results:
1044  *	True, False or Err
1045  *
1046  * Side Effects:
1047  *	Tokens are consumed.
1048  *
1049  *-----------------------------------------------------------------------
1050  */
1051 static Token
1052 CondF(Boolean doEval)
1053 {
1054     Token   l, o;
1055 
1056     l = CondT(doEval);
1057     if (l != Err) {
1058 	o = CondToken(doEval);
1059 
1060 	if (o == And) {
1061 	    /*
1062 	     * F -> T && F
1063 	     *
1064 	     * If T is False, the whole thing will be False, but we have to
1065 	     * parse the r.h.s. anyway (to throw it away).
1066 	     * If T is True, the result is the r.h.s., be it an Err or no.
1067 	     */
1068 	    if (l == True) {
1069 		l = CondF(doEval);
1070 	    } else {
1071 		(void) CondF(FALSE);
1072 	    }
1073 	} else {
1074 	    /*
1075 	     * F -> T
1076 	     */
1077 	    CondPushBack (o);
1078 	}
1079     }
1080     return (l);
1081 }
1082 
1083 /*-
1084  *-----------------------------------------------------------------------
1085  * CondE --
1086  *	Main expression production.
1087  *	    E -> F || E | F
1088  *
1089  * Results:
1090  *	True, False or Err.
1091  *
1092  * Side Effects:
1093  *	Tokens are, of course, consumed.
1094  *
1095  *-----------------------------------------------------------------------
1096  */
1097 static Token
1098 CondE(Boolean doEval)
1099 {
1100     Token   l, o;
1101 
1102     l = CondF(doEval);
1103     if (l != Err) {
1104 	o = CondToken(doEval);
1105 
1106 	if (o == Or) {
1107 	    /*
1108 	     * E -> F || E
1109 	     *
1110 	     * A similar thing occurs for ||, except that here we make sure
1111 	     * the l.h.s. is False before we bother to evaluate the r.h.s.
1112 	     * Once again, if l is False, the result is the r.h.s. and once
1113 	     * again if l is True, we parse the r.h.s. to throw it away.
1114 	     */
1115 	    if (l == False) {
1116 		l = CondE(doEval);
1117 	    } else {
1118 		(void) CondE(FALSE);
1119 	    }
1120 	} else {
1121 	    /*
1122 	     * E -> F
1123 	     */
1124 	    CondPushBack (o);
1125 	}
1126     }
1127     return (l);
1128 }
1129 
1130 /*-
1131  *-----------------------------------------------------------------------
1132  * Cond_EvalExpression --
1133  *	Evaluate an expression in the passed line. The expression
1134  *	consists of &&, ||, !, make(target), defined(variable)
1135  *	and parenthetical groupings thereof.
1136  *
1137  * Results:
1138  *	COND_PARSE	if the condition was valid grammatically
1139  *	COND_INVALID  	if not a valid conditional.
1140  *
1141  *	(*value) is set to the boolean value of the condition
1142  *
1143  * Side Effects:
1144  *	None.
1145  *
1146  *-----------------------------------------------------------------------
1147  */
1148 int
1149 Cond_EvalExpression(int dosetup, char *line, Boolean *value, int eprint)
1150 {
1151     if (dosetup) {
1152 	condDefProc = CondDoDefined;
1153 	condInvert = 0;
1154     }
1155 
1156     while (*line == ' ' || *line == '\t')
1157 	line++;
1158 
1159     condExpr = line;
1160     condPushBack = None;
1161 
1162     switch (CondE(TRUE)) {
1163     case True:
1164 	if (CondToken(TRUE) == EndOfFile) {
1165 	    *value = TRUE;
1166 	    break;
1167 	}
1168 	goto err;
1169 	/*FALLTHRU*/
1170     case False:
1171 	if (CondToken(TRUE) == EndOfFile) {
1172 	    *value = FALSE;
1173 	    break;
1174 	}
1175 	/*FALLTHRU*/
1176     case Err:
1177 err:
1178 	if (eprint)
1179 	    Parse_Error (PARSE_FATAL, "Malformed conditional (%s)",
1180 			 line);
1181 	return (COND_INVALID);
1182     default:
1183 	break;
1184     }
1185 
1186     return COND_PARSE;
1187 }
1188 
1189 
1190 /*-
1191  *-----------------------------------------------------------------------
1192  * Cond_Eval --
1193  *	Evaluate the conditional in the passed line. The line
1194  *	looks like this:
1195  *	    #<cond-type> <expr>
1196  *	where <cond-type> is any of if, ifmake, ifnmake, ifdef,
1197  *	ifndef, elif, elifmake, elifnmake, elifdef, elifndef
1198  *	and <expr> consists of &&, ||, !, make(target), defined(variable)
1199  *	and parenthetical groupings thereof.
1200  *
1201  * Input:
1202  *	line		Line to parse
1203  *
1204  * Results:
1205  *	COND_PARSE	if should parse lines after the conditional
1206  *	COND_SKIP	if should skip lines after the conditional
1207  *	COND_INVALID  	if not a valid conditional.
1208  *
1209  * Side Effects:
1210  *	None.
1211  *
1212  *-----------------------------------------------------------------------
1213  */
1214 int
1215 Cond_Eval(char *line)
1216 {
1217     struct If	    *ifp;
1218     Boolean 	    isElse;
1219     Boolean 	    value = FALSE;
1220     int	    	    level;  	/* Level at which to report errors. */
1221 
1222     level = PARSE_FATAL;
1223 
1224     for (line++; *line == ' ' || *line == '\t'; line++) {
1225 	continue;
1226     }
1227 
1228     /*
1229      * Find what type of if we're dealing with. The result is left
1230      * in ifp and isElse is set TRUE if it's an elif line.
1231      */
1232     if (line[0] == 'e' && line[1] == 'l') {
1233 	line += 2;
1234 	isElse = TRUE;
1235     } else if (strncmp (line, "endif", 5) == 0) {
1236 	/*
1237 	 * End of a conditional section. If skipIfLevel is non-zero, that
1238 	 * conditional was skipped, so lines following it should also be
1239 	 * skipped. Hence, we return COND_SKIP. Otherwise, the conditional
1240 	 * was read so succeeding lines should be parsed (think about it...)
1241 	 * so we return COND_PARSE, unless this endif isn't paired with
1242 	 * a decent if.
1243 	 */
1244 	finalElse[condTop][skipIfLevel] = FALSE;
1245 	if (skipIfLevel != 0) {
1246 	    skipIfLevel -= 1;
1247 	    return (COND_SKIP);
1248 	} else {
1249 	    if (condTop == MAXIF) {
1250 		Parse_Error (level, "if-less endif");
1251 		return (COND_INVALID);
1252 	    } else {
1253 		skipLine = FALSE;
1254 		condTop += 1;
1255 		return (COND_PARSE);
1256 	    }
1257 	}
1258     } else {
1259 	isElse = FALSE;
1260     }
1261 
1262     /*
1263      * Figure out what sort of conditional it is -- what its default
1264      * function is, etc. -- by looking in the table of valid "ifs"
1265      */
1266     for (ifp = ifs; ifp->form != (char *)0; ifp++) {
1267 	if (strncmp (ifp->form, line, ifp->formlen) == 0) {
1268 	    break;
1269 	}
1270     }
1271 
1272     if (ifp->form == (char *) 0) {
1273 	/*
1274 	 * Nothing fit. If the first word on the line is actually
1275 	 * "else", it's a valid conditional whose value is the inverse
1276 	 * of the previous if we parsed.
1277 	 */
1278 	if (isElse && (line[0] == 's') && (line[1] == 'e')) {
1279 	    if (finalElse[condTop][skipIfLevel]) {
1280 		Parse_Error (PARSE_WARNING, "extra else");
1281 	    } else {
1282 		finalElse[condTop][skipIfLevel] = TRUE;
1283 	    }
1284 	    if (condTop == MAXIF) {
1285 		Parse_Error (level, "if-less else");
1286 		return (COND_INVALID);
1287 	    } else if (skipIfLevel == 0) {
1288 		value = !condStack[condTop];
1289 	    } else {
1290 		return (COND_SKIP);
1291 	    }
1292 	} else {
1293 	    /*
1294 	     * Not a valid conditional type. No error...
1295 	     */
1296 	    return (COND_INVALID);
1297 	}
1298     } else {
1299 	if (isElse) {
1300 	    if (condTop == MAXIF) {
1301 		Parse_Error (level, "if-less elif");
1302 		return (COND_INVALID);
1303 	    } else if (skipIfLevel != 0) {
1304 		/*
1305 		 * If skipping this conditional, just ignore the whole thing.
1306 		 * If we don't, the user might be employing a variable that's
1307 		 * undefined, for which there's an enclosing ifdef that
1308 		 * we're skipping...
1309 		 */
1310 		return(COND_SKIP);
1311 	    }
1312 	} else if (skipLine) {
1313 	    /*
1314 	     * Don't even try to evaluate a conditional that's not an else if
1315 	     * we're skipping things...
1316 	     */
1317 	    skipIfLevel += 1;
1318 	    if (skipIfLevel >= MAXIF) {
1319 		Parse_Error (PARSE_FATAL, "Too many nested if's. %d max.", MAXIF);
1320 		return (COND_INVALID);
1321 	    }
1322 	    finalElse[condTop][skipIfLevel] = FALSE;
1323 	    return(COND_SKIP);
1324 	}
1325 
1326 	/*
1327 	 * Initialize file-global variables for parsing
1328 	 */
1329 	condDefProc = ifp->defProc;
1330 	condInvert = ifp->doNot;
1331 
1332 	line += ifp->formlen;
1333 	if (Cond_EvalExpression(0, line, &value, 1) == COND_INVALID)
1334 		return COND_INVALID;
1335     }
1336     if (!isElse) {
1337 	condTop -= 1;
1338 	finalElse[condTop][skipIfLevel] = FALSE;
1339     } else if ((skipIfLevel != 0) || condStack[condTop]) {
1340 	/*
1341 	 * If this is an else-type conditional, it should only take effect
1342 	 * if its corresponding if was evaluated and FALSE. If its if was
1343 	 * TRUE or skipped, we return COND_SKIP (and start skipping in case
1344 	 * we weren't already), leaving the stack unmolested so later elif's
1345 	 * don't screw up...
1346 	 */
1347 	skipLine = TRUE;
1348 	return (COND_SKIP);
1349     }
1350 
1351     if (condTop < 0) {
1352 	/*
1353 	 * This is the one case where we can definitely proclaim a fatal
1354 	 * error. If we don't, we're hosed.
1355 	 */
1356 	Parse_Error (PARSE_FATAL, "Too many nested if's. %d max.", MAXIF);
1357 	return (COND_INVALID);
1358     } else {
1359 	condStack[condTop] = value;
1360 	skipLine = !value;
1361 	return (value ? COND_PARSE : COND_SKIP);
1362     }
1363 }
1364 
1365 
1366 
1367 /*-
1368  *-----------------------------------------------------------------------
1369  * Cond_End --
1370  *	Make sure everything's clean at the end of a makefile.
1371  *
1372  * Results:
1373  *	None.
1374  *
1375  * Side Effects:
1376  *	Parse_Error will be called if open conditionals are around.
1377  *
1378  *-----------------------------------------------------------------------
1379  */
1380 void
1381 Cond_End(void)
1382 {
1383     if (condTop != MAXIF) {
1384 	Parse_Error(PARSE_FATAL, "%d open conditional%s", MAXIF-condTop,
1385 		    MAXIF-condTop == 1 ? "" : "s");
1386     }
1387     condTop = MAXIF;
1388 }
1389