xref: /netbsd-src/usr.bin/make/cond.c (revision 10ad5ffa714ce1a679dcc9dd8159648df2d67b5a)
1 /*	$NetBSD: cond.c,v 1.59 2009/01/30 23:07:17 dsl 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 1.59 2009/01/30 23:07:17 dsl 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 1.59 2009/01/30 23:07:17 dsl 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 '||', TOK_NOT for '!',
128  * TOK_LPAREN for '(', TOK_RPAREN for ')' and will evaluate the other terminal
129  * symbols, using either the default function or the function given in the
130  * terminal, and return the result as either TOK_TRUE or TOK_FALSE.
131  *
132  * All Non-Terminal functions (CondE, CondF and CondT) return TOK_ERROR on error.
133  */
134 typedef enum {
135     TOK_AND, TOK_OR, TOK_NOT, TOK_TRUE, TOK_FALSE, TOK_LPAREN, TOK_RPAREN,
136     TOK_EOF, TOK_NONE, TOK_ERROR
137 } Token;
138 
139 /*-
140  * Structures to handle elegantly the different forms of #if's. The
141  * last two fields are stored in condInvert and condDefProc, respectively.
142  */
143 static void CondPushBack(Token);
144 static int CondGetArg(char **, char **, const char *);
145 static Boolean CondDoDefined(int, const char *);
146 static int CondStrMatch(const void *, const void *);
147 static Boolean CondDoMake(int, const char *);
148 static Boolean CondDoExists(int, const char *);
149 static Boolean CondDoTarget(int, const char *);
150 static Boolean CondDoCommands(int, const char *);
151 static Boolean CondCvtArg(char *, double *);
152 static Token CondToken(Boolean);
153 static Token CondT(Boolean);
154 static Token CondF(Boolean);
155 static Token CondE(Boolean);
156 static int do_Cond_EvalExpression(Boolean *);
157 
158 static const struct If {
159     const char	*form;	      /* Form of if */
160     int		formlen;      /* Length of form */
161     Boolean	doNot;	      /* TRUE if default function should be negated */
162     Boolean	(*defProc)(int, const char *); /* Default function to apply */
163 } ifs[] = {
164     { "def",	  3,	  FALSE,  CondDoDefined },
165     { "ndef",	  4,	  TRUE,	  CondDoDefined },
166     { "make",	  4,	  FALSE,  CondDoMake },
167     { "nmake",	  5,	  TRUE,	  CondDoMake },
168     { "",	  0,	  FALSE,  CondDoDefined },
169     { NULL,	  0,	  FALSE,  NULL }
170 };
171 
172 static const struct If *if_info;        /* Info for current statement */
173 static char 	  *condExpr;	    	/* The expression to parse */
174 static Token	  condPushBack=TOK_NONE;	/* Single push-back token used in
175 					 * parsing */
176 
177 static unsigned int	cond_depth = 0;  	/* current .if nesting level */
178 static unsigned int	cond_min_depth = 0;  	/* depth at makefile open */
179 
180 static int
181 istoken(const char *str, const char *tok, size_t len)
182 {
183 	return strncmp(str, tok, len) == 0 && !isalpha((unsigned char)str[len]);
184 }
185 
186 /*-
187  *-----------------------------------------------------------------------
188  * CondPushBack --
189  *	Push back the most recent token read. We only need one level of
190  *	this, so the thing is just stored in 'condPushback'.
191  *
192  * Input:
193  *	t		Token to push back into the "stream"
194  *
195  * Results:
196  *	None.
197  *
198  * Side Effects:
199  *	condPushback is overwritten.
200  *
201  *-----------------------------------------------------------------------
202  */
203 static void
204 CondPushBack(Token t)
205 {
206     condPushBack = t;
207 }
208 
209 /*-
210  *-----------------------------------------------------------------------
211  * CondGetArg --
212  *	Find the argument of a built-in function.
213  *
214  * Input:
215  *	parens		TRUE if arg should be bounded by parens
216  *
217  * Results:
218  *	The length of the argument and the address of the argument.
219  *
220  * Side Effects:
221  *	The pointer is set to point to the closing parenthesis of the
222  *	function call.
223  *
224  *-----------------------------------------------------------------------
225  */
226 static int
227 CondGetArg(char **linePtr, char **argPtr, const char *func)
228 {
229     char	  *cp;
230     int	    	  argLen;
231     Buffer	  buf;
232     int           paren_depth;
233     char          ch;
234 
235     cp = *linePtr;
236     if (func != NULL)
237 	/* Skip opening '(' - verfied by caller */
238 	cp++;
239 
240     if (*cp == '\0') {
241 	/*
242 	 * No arguments whatsoever. Because 'make' and 'defined' aren't really
243 	 * "reserved words", we don't print a message. I think this is better
244 	 * than hitting the user with a warning message every time s/he uses
245 	 * the word 'make' or 'defined' at the beginning of a symbol...
246 	 */
247 	*argPtr = NULL;
248 	return (0);
249     }
250 
251     while (*cp == ' ' || *cp == '\t') {
252 	cp++;
253     }
254 
255     /*
256      * Create a buffer for the argument and start it out at 16 characters
257      * long. Why 16? Why not?
258      */
259     Buf_Init(&buf, 16);
260 
261     paren_depth = 0;
262     for (;;) {
263 	ch = *cp;
264 	if (ch == 0 || ch == ' ' || ch == '\t')
265 	    break;
266 	if ((ch == '&' || ch == '|') && paren_depth == 0)
267 	    break;
268 	if (*cp == '$') {
269 	    /*
270 	     * Parse the variable spec and install it as part of the argument
271 	     * if it's valid. We tell Var_Parse to complain on an undefined
272 	     * variable, so we don't do it too. Nor do we return an error,
273 	     * though perhaps we should...
274 	     */
275 	    char  	*cp2;
276 	    int		len;
277 	    void	*freeIt;
278 
279 	    cp2 = Var_Parse(cp, VAR_CMD, TRUE, &len, &freeIt);
280 	    Buf_AddBytes(&buf, strlen(cp2), cp2);
281 	    if (freeIt)
282 		free(freeIt);
283 	    cp += len;
284 	    continue;
285 	}
286 	if (ch == '(')
287 	    paren_depth++;
288 	else
289 	    if (ch == ')' && --paren_depth < 0)
290 		break;
291 	Buf_AddByte(&buf, *cp);
292 	cp++;
293     }
294 
295     *argPtr = Buf_GetAll(&buf, &argLen);
296     Buf_Destroy(&buf, FALSE);
297 
298     while (*cp == ' ' || *cp == '\t') {
299 	cp++;
300     }
301 
302     if (func != NULL && *cp++ != ')') {
303 	Parse_Error(PARSE_WARNING, "Missing closing parenthesis for %s()",
304 		     func);
305 	return (0);
306     }
307 
308     *linePtr = cp;
309     return (argLen);
310 }
311 
312 /*-
313  *-----------------------------------------------------------------------
314  * CondDoDefined --
315  *	Handle the 'defined' function for conditionals.
316  *
317  * Results:
318  *	TRUE if the given variable is defined.
319  *
320  * Side Effects:
321  *	None.
322  *
323  *-----------------------------------------------------------------------
324  */
325 static Boolean
326 CondDoDefined(int argLen, const char *arg)
327 {
328     char    *p1;
329     Boolean result;
330 
331     if (Var_Value(arg, VAR_CMD, &p1) != NULL) {
332 	result = TRUE;
333     } else {
334 	result = FALSE;
335     }
336     if (p1)
337 	free(p1);
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(const void *string, const void *pattern)
357 {
358     return(!Str_Match(string, 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, const char *arg)
376 {
377     return Lst_Find(create, arg, CondStrMatch) != NULL;
378 }
379 
380 /*-
381  *-----------------------------------------------------------------------
382  * CondDoExists --
383  *	See if the given file exists.
384  *
385  * Results:
386  *	TRUE if the file exists and FALSE if it does not.
387  *
388  * Side Effects:
389  *	None.
390  *
391  *-----------------------------------------------------------------------
392  */
393 static Boolean
394 CondDoExists(int argLen, const char *arg)
395 {
396     Boolean result;
397     char    *path;
398 
399     path = Dir_FindFile(arg, dirSearchPath);
400     if (path != NULL) {
401 	result = TRUE;
402 	free(path);
403     } else {
404 	result = FALSE;
405     }
406     if (DEBUG(COND)) {
407 	fprintf(debug_file, "exists(%s) result is \"%s\"\n",
408 	       arg, path ? path : "");
409     }
410     return (result);
411 }
412 
413 /*-
414  *-----------------------------------------------------------------------
415  * CondDoTarget --
416  *	See if the given node exists and is an actual target.
417  *
418  * Results:
419  *	TRUE if the node exists as a target and FALSE if it does not.
420  *
421  * Side Effects:
422  *	None.
423  *
424  *-----------------------------------------------------------------------
425  */
426 static Boolean
427 CondDoTarget(int argLen, const char *arg)
428 {
429     GNode   *gn;
430 
431     gn = Targ_FindNode(arg, TARG_NOCREATE);
432     return (gn != NULL) && !OP_NOP(gn->type);
433 }
434 
435 /*-
436  *-----------------------------------------------------------------------
437  * CondDoCommands --
438  *	See if the given node exists and is an actual target with commands
439  *	associated with it.
440  *
441  * Results:
442  *	TRUE if the node exists as a target and has commands associated with
443  *	it and FALSE if it does not.
444  *
445  * Side Effects:
446  *	None.
447  *
448  *-----------------------------------------------------------------------
449  */
450 static Boolean
451 CondDoCommands(int argLen, const char *arg)
452 {
453     GNode   *gn;
454 
455     gn = Targ_FindNode(arg, TARG_NOCREATE);
456     return (gn != NULL) && !OP_NOP(gn->type) && !Lst_IsEmpty(gn->commands);
457 }
458 
459 /*-
460  *-----------------------------------------------------------------------
461  * CondCvtArg --
462  *	Convert the given number into a double.
463  *	We try a base 10 or 16 integer conversion first, if that fails
464  *	then we try a floating point conversion instead.
465  *
466  * Results:
467  *	Sets 'value' to double value of string.
468  *	Returns 'true' if the convertion suceeded
469  *
470  *-----------------------------------------------------------------------
471  */
472 static Boolean
473 CondCvtArg(char *str, double *value)
474 {
475     char *eptr, ech;
476     unsigned long l_val;
477     double d_val;
478 
479     errno = 0;
480     l_val = strtoul(str, &eptr, str[1] == 'x' ? 16 : 10);
481     ech = *eptr;
482     if (ech == 0 && errno != ERANGE) {
483 	d_val = str[0] == '-' ? -(double)-l_val : (double)l_val;
484     } else {
485 	if (ech != 0 && ech != '.' && ech != 'e' && ech != 'E')
486 	    return FALSE;
487 	d_val = strtod(str, &eptr);
488 	if (*eptr)
489 	    return FALSE;
490     }
491 
492     *value = d_val;
493     return TRUE;
494 }
495 
496 /*-
497  *-----------------------------------------------------------------------
498  * CondGetString --
499  *	Get a string from a variable reference or an optionally quoted
500  *	string.  This is called for the lhs and rhs of string compares.
501  *
502  * Results:
503  *	Sets freeIt if needed,
504  *	Sets quoted if string was quoted,
505  *	Returns NULL on error,
506  *	else returns string - absent any quotes.
507  *
508  * Side Effects:
509  *	Moves condExpr to end of this token.
510  *
511  *
512  *-----------------------------------------------------------------------
513  */
514 /* coverity:[+alloc : arg-*2] */
515 static char *
516 CondGetString(Boolean doEval, Boolean *quoted, void **freeIt)
517 {
518     Buffer buf;
519     char *cp;
520     char *str;
521     int	len;
522     int qt;
523     char *start;
524 
525     Buf_Init(&buf, 0);
526     str = NULL;
527     *freeIt = NULL;
528     *quoted = qt = *condExpr == '"' ? 1 : 0;
529     if (qt)
530 	condExpr++;
531     for (start = condExpr; *condExpr && str == NULL; condExpr++) {
532 	switch (*condExpr) {
533 	case '\\':
534 	    if (condExpr[1] != '\0') {
535 		condExpr++;
536 		Buf_AddByte(&buf, *condExpr);
537 	    }
538 	    break;
539 	case '"':
540 	    if (qt) {
541 		condExpr++;		/* we don't want the quotes */
542 		goto got_str;
543 	    } else
544 		Buf_AddByte(&buf, *condExpr); /* likely? */
545 	    break;
546 	case ')':
547 	case '!':
548 	case '=':
549 	case '>':
550 	case '<':
551 	case ' ':
552 	case '\t':
553 	    if (!qt)
554 		goto got_str;
555 	    else
556 		Buf_AddByte(&buf, *condExpr);
557 	    break;
558 	case '$':
559 	    /* if we are in quotes, then an undefined variable is ok */
560 	    str = Var_Parse(condExpr, VAR_CMD, (qt ? 0 : doEval),
561 			    &len, freeIt);
562 	    if (str == var_Error) {
563 		if (*freeIt) {
564 		    free(*freeIt);
565 		    *freeIt = NULL;
566 		}
567 		/*
568 		 * Even if !doEval, we still report syntax errors, which
569 		 * is what getting var_Error back with !doEval means.
570 		 */
571 		str = NULL;
572 		goto cleanup;
573 	    }
574 	    condExpr += len;
575 	    /*
576 	     * If the '$' was first char (no quotes), and we are
577 	     * followed by space, the operator or end of expression,
578 	     * we are done.
579 	     */
580 	    if ((condExpr == start + len) &&
581 		(*condExpr == '\0' ||
582 		 isspace((unsigned char) *condExpr) ||
583 		 strchr("!=><)", *condExpr))) {
584 		goto cleanup;
585 	    }
586 	    /*
587 	     * Nope, we better copy str to buf
588 	     */
589 	    for (cp = str; *cp; cp++) {
590 		Buf_AddByte(&buf, *cp);
591 	    }
592 	    if (*freeIt) {
593 		free(*freeIt);
594 		*freeIt = NULL;
595 	    }
596 	    str = NULL;			/* not finished yet */
597 	    condExpr--;			/* don't skip over next char */
598 	    break;
599 	default:
600 	    Buf_AddByte(&buf, *condExpr);
601 	    break;
602 	}
603     }
604  got_str:
605     str = Buf_GetAll(&buf, NULL);
606     *freeIt = str;
607  cleanup:
608     Buf_Destroy(&buf, FALSE);
609     return str;
610 }
611 
612 /*-
613  *-----------------------------------------------------------------------
614  * CondToken --
615  *	Return the next token from the input.
616  *
617  * Results:
618  *	A Token for the next lexical token in the stream.
619  *
620  * Side Effects:
621  *	condPushback will be set back to TOK_NONE if it is used.
622  *
623  *-----------------------------------------------------------------------
624  */
625 static Token
626 compare_expression(Boolean doEval)
627 {
628     Token	t;
629     char	*lhs;
630     char	*rhs;
631     char	*op;
632     void	*lhsFree;
633     void	*rhsFree;
634     Boolean lhsQuoted;
635     Boolean rhsQuoted;
636     double  	left, right;
637 
638     t = TOK_ERROR;
639     rhs = NULL;
640     lhsFree = rhsFree = FALSE;
641     lhsQuoted = rhsQuoted = FALSE;
642 
643     /*
644      * Parse the variable spec and skip over it, saving its
645      * value in lhs.
646      */
647     lhs = CondGetString(doEval, &lhsQuoted, &lhsFree);
648     if (!lhs)
649 	goto done;
650 
651     /*
652      * Skip whitespace to get to the operator
653      */
654     while (isspace((unsigned char) *condExpr))
655 	condExpr++;
656 
657     /*
658      * Make sure the operator is a valid one. If it isn't a
659      * known relational operator, pretend we got a
660      * != 0 comparison.
661      */
662     op = condExpr;
663     switch (*condExpr) {
664 	case '!':
665 	case '=':
666 	case '<':
667 	case '>':
668 	    if (condExpr[1] == '=') {
669 		condExpr += 2;
670 	    } else {
671 		condExpr += 1;
672 	    }
673 	    break;
674 	default:
675 	    if (!doEval) {
676 		t = TOK_FALSE;
677 		goto done;
678 	    }
679 	    /* For .ifxxx "..." check for non-empty string. */
680 	    if (lhsQuoted) {
681 		t = lhs[0] != 0 ? TOK_TRUE : TOK_FALSE;
682 		goto done;
683 	    }
684 	    /* For .ifxxx <number> compare against zero */
685 	    if (CondCvtArg(lhs, &left)) {
686 		t = left != 0.0 ? TOK_TRUE : TOK_FALSE;
687 		goto done;
688 	    }
689 	    /* For .if ${...} check for non-empty string (defProc is ifdef). */
690 	    if (if_info->form[0] == 0) {
691 		t = lhs[0] != 0 ? TOK_TRUE : TOK_FALSE;
692 		goto done;
693 	    }
694 	    /* Otherwise action default test ... */
695 	    t = if_info->defProc(strlen(lhs), lhs) != if_info->doNot ? TOK_TRUE : TOK_FALSE;
696 	    goto done;
697     }
698 
699     while (isspace((unsigned char)*condExpr))
700 	condExpr++;
701 
702     if (*condExpr == '\0') {
703 	Parse_Error(PARSE_WARNING,
704 		    "Missing right-hand-side of operator");
705 	goto done;
706     }
707 
708     rhs = CondGetString(doEval, &rhsQuoted, &rhsFree);
709     if (!rhs)
710 	goto done;
711 
712     if (rhsQuoted || lhsQuoted) {
713 do_string_compare:
714 	if (((*op != '!') && (*op != '=')) || (op[1] != '=')) {
715 	    Parse_Error(PARSE_WARNING,
716     "String comparison operator should be either == or !=");
717 	    goto done;
718 	}
719 
720 	if (DEBUG(COND)) {
721 	    fprintf(debug_file, "lhs = \"%s\", rhs = \"%s\", op = %.2s\n",
722 		   lhs, rhs, op);
723 	}
724 	/*
725 	 * Null-terminate rhs and perform the comparison.
726 	 * t is set to the result.
727 	 */
728 	if (*op == '=') {
729 	    t = strcmp(lhs, rhs) ? TOK_FALSE : TOK_TRUE;
730 	} else {
731 	    t = strcmp(lhs, rhs) ? TOK_TRUE : TOK_FALSE;
732 	}
733     } else {
734 	/*
735 	 * rhs is either a float or an integer. Convert both the
736 	 * lhs and the rhs to a double and compare the two.
737 	 */
738 
739 	if (!CondCvtArg(lhs, &left) || !CondCvtArg(rhs, &right))
740 	    goto do_string_compare;
741 
742 	if (DEBUG(COND)) {
743 	    fprintf(debug_file, "left = %f, right = %f, op = %.2s\n", left,
744 		   right, op);
745 	}
746 	switch(op[0]) {
747 	case '!':
748 	    if (op[1] != '=') {
749 		Parse_Error(PARSE_WARNING,
750 			    "Unknown operator");
751 		goto done;
752 	    }
753 	    t = (left != right ? TOK_TRUE : TOK_FALSE);
754 	    break;
755 	case '=':
756 	    if (op[1] != '=') {
757 		Parse_Error(PARSE_WARNING,
758 			    "Unknown operator");
759 		goto done;
760 	    }
761 	    t = (left == right ? TOK_TRUE : TOK_FALSE);
762 	    break;
763 	case '<':
764 	    if (op[1] == '=') {
765 		t = (left <= right ? TOK_TRUE : TOK_FALSE);
766 	    } else {
767 		t = (left < right ? TOK_TRUE : TOK_FALSE);
768 	    }
769 	    break;
770 	case '>':
771 	    if (op[1] == '=') {
772 		t = (left >= right ? TOK_TRUE : TOK_FALSE);
773 	    } else {
774 		t = (left > right ? TOK_TRUE : TOK_FALSE);
775 	    }
776 	    break;
777 	}
778     }
779 
780 done:
781     if (lhsFree)
782 	free(lhsFree);
783     if (rhsFree)
784 	free(rhsFree);
785     return t;
786 }
787 
788 static int
789 get_mpt_arg(char **linePtr, char **argPtr, const char *func)
790 {
791     /*
792      * Use Var_Parse to parse the spec in parens and return
793      * TOK_TRUE if the resulting string is empty.
794      */
795     int	    length;
796     void    *freeIt;
797     char    *val;
798     char    *cp = *linePtr;
799 
800     /* We do all the work here and return the result as the length */
801     *argPtr = NULL;
802 
803     val = Var_Parse(cp - 1, VAR_CMD, FALSE, &length, &freeIt);
804     /*
805      * Advance *linePtr to beyond the closing ). Note that
806      * we subtract one because 'length' is calculated from 'cp - 1'.
807      */
808     *linePtr = cp - 1 + length;
809 
810     if (val == var_Error) {
811 	free(freeIt);
812 	return -1;
813     }
814 
815     /* A variable is empty when it just contains spaces... 4/15/92, christos */
816     while (isspace(*(unsigned char *)val))
817 	val++;
818 
819     /*
820      * For consistency with the other functions we can't generate the
821      * true/false here.
822      */
823     length = *val ? 2 : 1;
824     if (freeIt)
825 	free(freeIt);
826     return length;
827 }
828 
829 static Boolean
830 CondDoEmpty(int arglen, const char *arg)
831 {
832     return arglen == 1;
833 }
834 
835 static Token
836 compare_function(Boolean doEval)
837 {
838     static const struct fn_def {
839 	const char  *fn_name;
840 	int         fn_name_len;
841         int         (*fn_getarg)(char **, char **, const char *);
842 	Boolean     (*fn_proc)(int, const char *);
843     } fn_defs[] = {
844 	{ "defined",   7, CondGetArg, CondDoDefined },
845 	{ "make",      4, CondGetArg, CondDoMake },
846 	{ "exists",    6, CondGetArg, CondDoExists },
847 	{ "empty",     5, get_mpt_arg, CondDoEmpty },
848 	{ "target",    6, CondGetArg, CondDoTarget },
849 	{ "commands",  8, CondGetArg, CondDoCommands },
850 	{ NULL,        0, NULL, NULL },
851     };
852     const struct fn_def *fn_def;
853     Token	t;
854     char	*arg = NULL;
855     int	arglen;
856     char *cp = condExpr;
857     char *cp1;
858 
859     for (fn_def = fn_defs; fn_def->fn_name != NULL; fn_def++) {
860 	if (!istoken(cp, fn_def->fn_name, fn_def->fn_name_len))
861 	    continue;
862 	cp += fn_def->fn_name_len;
863 	/* There can only be whitespace before the '(' */
864 	while (isspace(*(unsigned char *)cp))
865 	    cp++;
866 	if (*cp != '(')
867 	    break;
868 
869 	arglen = fn_def->fn_getarg(&cp, &arg, fn_def->fn_name);
870 	if (arglen <= 0) {
871 	    condExpr = cp;
872 	    return arglen < 0 ? TOK_ERROR : TOK_FALSE;
873 	}
874 	/* Evaluate the argument using the required function. */
875 	t = !doEval || fn_def->fn_proc(arglen, arg) ? TOK_TRUE : TOK_FALSE;
876 	if (arg)
877 	    free(arg);
878 	condExpr = cp;
879 	return t;
880     }
881 
882     /* Push anything numeric through the compare expression */
883     cp = condExpr;
884     if (isdigit((unsigned char)cp[0]) || strchr("+-", cp[0]))
885 	return compare_expression(doEval);
886 
887     /*
888      * Most likely we have a naked token to apply the default function to.
889      * However ".if a == b" gets here when the "a" is unquoted and doesn't
890      * start with a '$'. This surprises people.
891      * If what follows the function argument is a '=' or '!' then the syntax
892      * would be invalid if we did "defined(a)" - so instead treat as an
893      * expression.
894      */
895     arglen = CondGetArg(&cp, &arg, NULL);
896     for (cp1 = cp; isspace(*(unsigned char *)cp1); cp1++)
897 	continue;
898     if (*cp1 == '=' || *cp1 == '!')
899 	return compare_expression(doEval);
900     condExpr = cp;
901 
902     /*
903      * Evaluate the argument using the default function.
904      * This path always treats .if as .ifdef. To get here the character
905      * after .if must have been taken literally, so the argument cannot
906      * be empty - even if it contained a variable expansion.
907      */
908     t = !doEval || if_info->defProc(arglen, arg) != if_info->doNot ? TOK_TRUE : TOK_FALSE;
909     if (arg)
910 	free(arg);
911     return t;
912 }
913 
914 static Token
915 CondToken(Boolean doEval)
916 {
917     Token t;
918 
919     t = condPushBack;
920     if (t != TOK_NONE) {
921 	condPushBack = TOK_NONE;
922 	return t;
923     }
924 
925     while (*condExpr == ' ' || *condExpr == '\t') {
926 	condExpr++;
927     }
928 
929     switch (*condExpr) {
930 
931     case '(':
932 	condExpr++;
933 	return TOK_LPAREN;
934 
935     case ')':
936 	condExpr++;
937 	return TOK_RPAREN;
938 
939     case '|':
940 	if (condExpr[1] == '|') {
941 	    condExpr++;
942 	}
943 	condExpr++;
944 	return TOK_OR;
945 
946     case '&':
947 	if (condExpr[1] == '&') {
948 	    condExpr++;
949 	}
950 	condExpr++;
951 	return TOK_AND;
952 
953     case '!':
954 	condExpr++;
955 	return TOK_NOT;
956 
957     case '#':
958     case '\n':
959     case '\0':
960 	return TOK_EOF;
961 
962     case '"':
963     case '$':
964 	return compare_expression(doEval);
965 
966     default:
967 	return compare_function(doEval);
968     }
969 }
970 
971 /*-
972  *-----------------------------------------------------------------------
973  * CondT --
974  *	Parse a single term in the expression. This consists of a terminal
975  *	symbol or TOK_NOT and a terminal symbol (not including the binary
976  *	operators):
977  *	    T -> defined(variable) | make(target) | exists(file) | symbol
978  *	    T -> ! T | ( E )
979  *
980  * Results:
981  *	TOK_TRUE, TOK_FALSE or TOK_ERROR.
982  *
983  * Side Effects:
984  *	Tokens are consumed.
985  *
986  *-----------------------------------------------------------------------
987  */
988 static Token
989 CondT(Boolean doEval)
990 {
991     Token   t;
992 
993     t = CondToken(doEval);
994 
995     if (t == TOK_EOF) {
996 	/*
997 	 * If we reached the end of the expression, the expression
998 	 * is malformed...
999 	 */
1000 	t = TOK_ERROR;
1001     } else if (t == TOK_LPAREN) {
1002 	/*
1003 	 * T -> ( E )
1004 	 */
1005 	t = CondE(doEval);
1006 	if (t != TOK_ERROR) {
1007 	    if (CondToken(doEval) != TOK_RPAREN) {
1008 		t = TOK_ERROR;
1009 	    }
1010 	}
1011     } else if (t == TOK_NOT) {
1012 	t = CondT(doEval);
1013 	if (t == TOK_TRUE) {
1014 	    t = TOK_FALSE;
1015 	} else if (t == TOK_FALSE) {
1016 	    t = TOK_TRUE;
1017 	}
1018     }
1019     return (t);
1020 }
1021 
1022 /*-
1023  *-----------------------------------------------------------------------
1024  * CondF --
1025  *	Parse a conjunctive factor (nice name, wot?)
1026  *	    F -> T && F | T
1027  *
1028  * Results:
1029  *	TOK_TRUE, TOK_FALSE or TOK_ERROR
1030  *
1031  * Side Effects:
1032  *	Tokens are consumed.
1033  *
1034  *-----------------------------------------------------------------------
1035  */
1036 static Token
1037 CondF(Boolean doEval)
1038 {
1039     Token   l, o;
1040 
1041     l = CondT(doEval);
1042     if (l != TOK_ERROR) {
1043 	o = CondToken(doEval);
1044 
1045 	if (o == TOK_AND) {
1046 	    /*
1047 	     * F -> T && F
1048 	     *
1049 	     * If T is TOK_FALSE, the whole thing will be TOK_FALSE, but we have to
1050 	     * parse the r.h.s. anyway (to throw it away).
1051 	     * If T is TOK_TRUE, the result is the r.h.s., be it an TOK_ERROR or no.
1052 	     */
1053 	    if (l == TOK_TRUE) {
1054 		l = CondF(doEval);
1055 	    } else {
1056 		(void)CondF(FALSE);
1057 	    }
1058 	} else {
1059 	    /*
1060 	     * F -> T
1061 	     */
1062 	    CondPushBack(o);
1063 	}
1064     }
1065     return (l);
1066 }
1067 
1068 /*-
1069  *-----------------------------------------------------------------------
1070  * CondE --
1071  *	Main expression production.
1072  *	    E -> F || E | F
1073  *
1074  * Results:
1075  *	TOK_TRUE, TOK_FALSE or TOK_ERROR.
1076  *
1077  * Side Effects:
1078  *	Tokens are, of course, consumed.
1079  *
1080  *-----------------------------------------------------------------------
1081  */
1082 static Token
1083 CondE(Boolean doEval)
1084 {
1085     Token   l, o;
1086 
1087     l = CondF(doEval);
1088     if (l != TOK_ERROR) {
1089 	o = CondToken(doEval);
1090 
1091 	if (o == TOK_OR) {
1092 	    /*
1093 	     * E -> F || E
1094 	     *
1095 	     * A similar thing occurs for ||, except that here we make sure
1096 	     * the l.h.s. is TOK_FALSE before we bother to evaluate the r.h.s.
1097 	     * Once again, if l is TOK_FALSE, the result is the r.h.s. and once
1098 	     * again if l is TOK_TRUE, we parse the r.h.s. to throw it away.
1099 	     */
1100 	    if (l == TOK_FALSE) {
1101 		l = CondE(doEval);
1102 	    } else {
1103 		(void)CondE(FALSE);
1104 	    }
1105 	} else {
1106 	    /*
1107 	     * E -> F
1108 	     */
1109 	    CondPushBack(o);
1110 	}
1111     }
1112     return (l);
1113 }
1114 
1115 /*-
1116  *-----------------------------------------------------------------------
1117  * Cond_EvalExpression --
1118  *	Evaluate an expression in the passed line. The expression
1119  *	consists of &&, ||, !, make(target), defined(variable)
1120  *	and parenthetical groupings thereof.
1121  *
1122  * Results:
1123  *	COND_PARSE	if the condition was valid grammatically
1124  *	COND_INVALID  	if not a valid conditional.
1125  *
1126  *	(*value) is set to the boolean value of the condition
1127  *
1128  * Side Effects:
1129  *	None.
1130  *
1131  *-----------------------------------------------------------------------
1132  */
1133 int
1134 Cond_EvalExpression(const struct If *info, char *line, Boolean *value, int eprint)
1135 {
1136     static const struct If *dflt_info;
1137     const struct If *sv_if_info = if_info;
1138     char *sv_condExpr = condExpr;
1139     Token sv_condPushBack = condPushBack;
1140     int rval;
1141 
1142     while (*line == ' ' || *line == '\t')
1143 	line++;
1144 
1145     if (info == NULL && (info = dflt_info) == NULL) {
1146 	/* Scan for the entry for .if - it can't be first */
1147 	for (info = ifs; ; info++)
1148 	    if (info->form[0] == 0)
1149 		break;
1150 	dflt_info = info;
1151     }
1152 
1153     if_info = info != NULL ? info : ifs + 4;
1154     condExpr = line;
1155     condPushBack = TOK_NONE;
1156 
1157     rval = do_Cond_EvalExpression(value);
1158 
1159     if (rval == COND_INVALID && eprint)
1160 	Parse_Error(PARSE_FATAL, "Malformed conditional (%s)", line);
1161 
1162     if_info = sv_if_info;
1163     condExpr = sv_condExpr;
1164     condPushBack = sv_condPushBack;
1165 
1166     return rval;
1167 }
1168 
1169 static int
1170 do_Cond_EvalExpression(Boolean *value)
1171 {
1172 
1173     switch (CondE(TRUE)) {
1174     case TOK_TRUE:
1175 	if (CondToken(TRUE) == TOK_EOF) {
1176 	    *value = TRUE;
1177 	    return COND_PARSE;
1178 	}
1179 	break;
1180     case TOK_FALSE:
1181 	if (CondToken(TRUE) == TOK_EOF) {
1182 	    *value = FALSE;
1183 	    return COND_PARSE;
1184 	}
1185 	break;
1186     default:
1187     case TOK_ERROR:
1188 	break;
1189     }
1190 
1191     return COND_INVALID;
1192 }
1193 
1194 
1195 /*-
1196  *-----------------------------------------------------------------------
1197  * Cond_Eval --
1198  *	Evaluate the conditional in the passed line. The line
1199  *	looks like this:
1200  *	    .<cond-type> <expr>
1201  *	where <cond-type> is any of if, ifmake, ifnmake, ifdef,
1202  *	ifndef, elif, elifmake, elifnmake, elifdef, elifndef
1203  *	and <expr> consists of &&, ||, !, make(target), defined(variable)
1204  *	and parenthetical groupings thereof.
1205  *
1206  * Input:
1207  *	line		Line to parse
1208  *
1209  * Results:
1210  *	COND_PARSE	if should parse lines after the conditional
1211  *	COND_SKIP	if should skip lines after the conditional
1212  *	COND_INVALID  	if not a valid conditional.
1213  *
1214  * Side Effects:
1215  *	None.
1216  *
1217  * Note that the states IF_ACTIVE and ELSE_ACTIVE are only different in order
1218  * to detect splurious .else lines (as are SKIP_TO_ELSE and SKIP_TO_ENDIF)
1219  * otherwise .else could be treated as '.elif 1'.
1220  *
1221  *-----------------------------------------------------------------------
1222  */
1223 int
1224 Cond_Eval(char *line)
1225 {
1226     #define	    MAXIF	64	/* maximum depth of .if'ing */
1227     enum if_states {
1228 	IF_ACTIVE,		/* .if or .elif part active */
1229 	ELSE_ACTIVE,		/* .else part active */
1230 	SEARCH_FOR_ELIF,	/* searching for .elif/else to execute */
1231 	SKIP_TO_ELSE,           /* has been true, but not seen '.else' */
1232 	SKIP_TO_ENDIF		/* nothing else to execute */
1233     };
1234     static enum if_states cond_state[MAXIF + 1] = { IF_ACTIVE };
1235 
1236     const struct If *ifp;
1237     Boolean 	    isElif;
1238     Boolean 	    value;
1239     int	    	    level;  	/* Level at which to report errors. */
1240     enum if_states  state;
1241 
1242     level = PARSE_FATAL;
1243 
1244     /* skip leading character (the '.') and any whitespace */
1245     for (line++; *line == ' ' || *line == '\t'; line++)
1246 	continue;
1247 
1248     /* Find what type of if we're dealing with.  */
1249     if (line[0] == 'e') {
1250 	if (line[1] != 'l') {
1251 	    if (!istoken(line + 1, "ndif", 4))
1252 		return COND_INVALID;
1253 	    /* End of conditional section */
1254 	    if (cond_depth == cond_min_depth) {
1255 		Parse_Error(level, "if-less endif");
1256 		return COND_PARSE;
1257 	    }
1258 	    /* Return state for previous conditional */
1259 	    cond_depth--;
1260 	    if (cond_depth > MAXIF)
1261 		return COND_SKIP;
1262 	    return cond_state[cond_depth] <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1263 	}
1264 
1265 	/* Quite likely this is 'else' or 'elif' */
1266 	line += 2;
1267 	if (istoken(line, "se", 2)) {
1268 	    /* It is else... */
1269 	    if (cond_depth == cond_min_depth) {
1270 		Parse_Error(level, "if-less else");
1271 		return COND_PARSE;
1272 	    }
1273 
1274 	    if (cond_depth > MAXIF)
1275 		return COND_SKIP;
1276 	    state = cond_state[cond_depth];
1277 	    switch (state) {
1278 	    case SEARCH_FOR_ELIF:
1279 		state = ELSE_ACTIVE;
1280 		break;
1281 	    case ELSE_ACTIVE:
1282 	    case SKIP_TO_ENDIF:
1283 		Parse_Error(PARSE_WARNING, "extra else");
1284 		/* FALLTHROUGH */
1285 	    default:
1286 	    case IF_ACTIVE:
1287 	    case SKIP_TO_ELSE:
1288 		state = SKIP_TO_ENDIF;
1289 		break;
1290 	    }
1291 	    cond_state[cond_depth] = state;
1292 	    return state <= ELSE_ACTIVE ? COND_PARSE : COND_SKIP;
1293 	}
1294 	/* Assume for now it is an elif */
1295 	isElif = TRUE;
1296     } else
1297 	isElif = FALSE;
1298 
1299     if (line[0] != 'i' || line[1] != 'f')
1300 	/* Not an ifxxx or elifxxx line */
1301 	return COND_INVALID;
1302 
1303     /*
1304      * Figure out what sort of conditional it is -- what its default
1305      * function is, etc. -- by looking in the table of valid "ifs"
1306      */
1307     line += 2;
1308     for (ifp = ifs; ; ifp++) {
1309 	if (ifp->form == NULL)
1310 	    return COND_INVALID;
1311 	if (istoken(ifp->form, line, ifp->formlen)) {
1312 	    line += ifp->formlen;
1313 	    break;
1314 	}
1315     }
1316 
1317     /* Now we know what sort of 'if' it is... */
1318 
1319     if (isElif) {
1320 	if (cond_depth == cond_min_depth) {
1321 	    Parse_Error(level, "if-less elif");
1322 	    return COND_PARSE;
1323 	}
1324 	if (cond_depth > MAXIF)
1325 	    /* Error reported when we saw the .if ... */
1326 	    return COND_SKIP;
1327 	state = cond_state[cond_depth];
1328 	if (state == SKIP_TO_ENDIF || state == ELSE_ACTIVE) {
1329 	    Parse_Error(PARSE_WARNING, "extra elif");
1330 	    cond_state[cond_depth] = SKIP_TO_ENDIF;
1331 	    return COND_SKIP;
1332 	}
1333 	if (state != SEARCH_FOR_ELIF) {
1334 	    /* Either just finished the 'true' block, or already SKIP_TO_ELSE */
1335 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1336 	    return COND_SKIP;
1337 	}
1338     } else {
1339 	/* Normal .if */
1340 	if (cond_depth >= MAXIF) {
1341 	    cond_depth++;
1342 	    Parse_Error(PARSE_FATAL, "Too many nested if's. %d max.", MAXIF);
1343 	    return COND_SKIP;
1344 	}
1345 	state = cond_state[cond_depth];
1346 	cond_depth++;
1347 	if (state > ELSE_ACTIVE) {
1348 	    /* If we aren't parsing the data, treat as always false */
1349 	    cond_state[cond_depth] = SKIP_TO_ELSE;
1350 	    return COND_SKIP;
1351 	}
1352     }
1353 
1354     /* And evaluate the conditional expresssion */
1355     if (Cond_EvalExpression(ifp, line, &value, 1) == COND_INVALID) {
1356 	/* Syntax error in conditional, error message already output. */
1357 	/* Skip everything to matching .endif */
1358 	cond_state[cond_depth] = SKIP_TO_ELSE;
1359 	return COND_SKIP;
1360     }
1361 
1362     if (!value) {
1363 	cond_state[cond_depth] = SEARCH_FOR_ELIF;
1364 	return COND_SKIP;
1365     }
1366     cond_state[cond_depth] = IF_ACTIVE;
1367     return COND_PARSE;
1368 }
1369 
1370 
1371 
1372 /*-
1373  *-----------------------------------------------------------------------
1374  * Cond_End --
1375  *	Make sure everything's clean at the end of a makefile.
1376  *
1377  * Results:
1378  *	None.
1379  *
1380  * Side Effects:
1381  *	Parse_Error will be called if open conditionals are around.
1382  *
1383  *-----------------------------------------------------------------------
1384  */
1385 void
1386 Cond_restore_depth(unsigned int saved_depth)
1387 {
1388     int open_conds = cond_depth - cond_min_depth;
1389 
1390     if (open_conds != 0 || saved_depth > cond_depth) {
1391 	Parse_Error(PARSE_FATAL, "%d open conditional%s", open_conds,
1392 		    open_conds == 1 ? "" : "s");
1393 	cond_depth = cond_min_depth;
1394     }
1395 
1396     cond_min_depth = saved_depth;
1397 }
1398 
1399 unsigned int
1400 Cond_save_depth(void)
1401 {
1402     int depth = cond_min_depth;
1403 
1404     cond_min_depth = cond_depth;
1405     return depth;
1406 }
1407