xref: /original-bsd/usr.bin/make/dir.c (revision 10020db5)
1 /*
2  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
3  * Copyright (c) 1988, 1989 by Adam de Boor
4  * Copyright (c) 1989 by Berkeley Softworks
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 are permitted
11  * provided that the above copyright notice and this paragraph are
12  * duplicated in all such forms and that any documentation,
13  * advertising materials, and other materials related to such
14  * distribution and use acknowledge that the software was developed
15  * by the University of California, Berkeley.  The name of the
16  * University may not be used to endorse or promote products derived
17  * from this software without specific prior written permission.
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21  */
22 
23 #ifndef lint
24 static char sccsid[] = "@(#)dir.c	5.4 (Berkeley) 03/19/90";
25 #endif /* not lint */
26 
27 /*-
28  * dir.c --
29  *	Directory searching using wildcards and/or normal names...
30  *	Used both for source wildcarding in the Makefile and for finding
31  *	implicit sources.
32  *
33  * The interface for this module is:
34  *	Dir_Init  	    Initialize the module.
35  *
36  *	Dir_HasWildcards    Returns TRUE if the name given it needs to
37  *	    	  	    be wildcard-expanded.
38  *
39  *	Dir_Expand	    Given a pattern and a path, return a Lst of names
40  *	    	  	    which match the pattern on the search path.
41  *
42  *	Dir_FindFile	    Searches for a file on a given search path.
43  *	    	  	    If it exists, the entire path is returned.
44  *	    	  	    Otherwise NULL is returned.
45  *
46  *	Dir_MTime 	    Return the modification time of a node. The file
47  *	    	  	    is searched for along the default search path.
48  *	    	  	    The path and mtime fields of the node are filled
49  *	    	  	    in.
50  *
51  *	Dir_AddDir	    Add a directory to a search path.
52  *
53  *	Dir_MakeFlags	    Given a search path and a command flag, create
54  *	    	  	    a string with each of the directories in the path
55  *	    	  	    preceded by the command flag and all of them
56  *	    	  	    separated by a space.
57  *
58  *	Dir_Destroy	    Destroy an element of a search path. Frees up all
59  *	    	  	    things that can be freed for the element as long
60  *	    	  	    as the element is no longer referenced by any other
61  *	    	  	    search path.
62  *	Dir_ClearPath	    Resets a search path to the empty list.
63  *
64  * For debugging:
65  *	Dir_PrintDirectories	Print stats about the directory cache.
66  */
67 
68 #include <stdio.h>
69 #include <sys/types.h>
70 #include <sys/dir.h>
71 #include <sys/stat.h>
72 #include "make.h"
73 #include "hash.h"
74 
75 /*
76  *	A search path consists of a Lst of Path structures. A Path structure
77  *	has in it the name of the directory and a hash table of all the files
78  *	in the directory. This is used to cut down on the number of system
79  *	calls necessary to find implicit dependents and their like. Since
80  *	these searches are made before any actions are taken, we need not
81  *	worry about the directory changing due to creation commands. If this
82  *	hampers the style of some makefiles, they must be changed.
83  *
84  *	A list of all previously-read directories is kept in the
85  *	openDirectories Lst. This list is checked first before a directory
86  *	is opened.
87  *
88  *	The need for the caching of whole directories is brought about by
89  *	the multi-level transformation code in suff.c, which tends to search
90  *	for far more files than regular make does. In the initial
91  *	implementation, the amount of time spent performing "stat" calls was
92  *	truly astronomical. The problem with hashing at the start is,
93  *	of course, that pmake doesn't then detect changes to these directories
94  *	during the course of the make. Three possibilities suggest themselves:
95  *
96  *	    1) just use stat to test for a file's existence. As mentioned
97  *	       above, this is very inefficient due to the number of checks
98  *	       engendered by the multi-level transformation code.
99  *	    2) use readdir() and company to search the directories, keeping
100  *	       them open between checks. I have tried this and while it
101  *	       didn't slow down the process too much, it could severely
102  *	       affect the amount of parallelism available as each directory
103  *	       open would take another file descriptor out of play for
104  *	       handling I/O for another job. Given that it is only recently
105  *	       that UNIX OS's have taken to allowing more than 20 or 32
106  *	       file descriptors for a process, this doesn't seem acceptable
107  *	       to me.
108  *	    3) record the mtime of the directory in the Path structure and
109  *	       verify the directory hasn't changed since the contents were
110  *	       hashed. This will catch the creation or deletion of files,
111  *	       but not the updating of files. However, since it is the
112  *	       creation and deletion that is the problem, this could be
113  *	       a good thing to do. Unfortunately, if the directory (say ".")
114  *	       were fairly large and changed fairly frequently, the constant
115  *	       rehashing could seriously degrade performance. It might be
116  *	       good in such cases to keep track of the number of rehashes
117  *	       and if the number goes over a (small) limit, resort to using
118  *	       stat in its place.
119  *
120  *	An additional thing to consider is that pmake is used primarily
121  *	to create C programs and until recently pcc-based compilers refused
122  *	to allow you to specify where the resulting object file should be
123  *	placed. This forced all objects to be created in the current
124  *	directory. This isn't meant as a full excuse, just an explanation of
125  *	some of the reasons for the caching used here.
126  *
127  *	One more note: the location of a target's file is only performed
128  *	on the downward traversal of the graph and then only for terminal
129  *	nodes in the graph. This could be construed as wrong in some cases,
130  *	but prevents inadvertent modification of files when the "installed"
131  *	directory for a file is provided in the search path.
132  *
133  *	Another data structure maintained by this module is an mtime
134  *	cache used when the searching of cached directories fails to find
135  *	a file. In the past, Dir_FindFile would simply perform an access()
136  *	call in such a case to determine if the file could be found using
137  *	just the name given. When this hit, however, all that was gained
138  *	was the knowledge that the file existed. Given that an access() is
139  *	essentially a stat() without the copyout() call, and that the same
140  *	filesystem overhead would have to be incurred in Dir_MTime, it made
141  *	sense to replace the access() with a stat() and record the mtime
142  *	in a cache for when Dir_MTime was actually called.
143  */
144 
145 Lst          dirSearchPath;	/* main search path */
146 
147 static Lst   openDirectories;	/* the list of all open directories */
148 
149 /*
150  * Variables for gathering statistics on the efficiency of the hashing
151  * mechanism.
152  */
153 static int    hits,	      /* Found in directory cache */
154 	      misses,	      /* Sad, but not evil misses */
155 	      nearmisses,     /* Found under search path */
156 	      bigmisses;      /* Sought by itself */
157 
158 typedef struct Path {
159     char         *name;	    	/* Name of directory */
160     int	    	  refCount; 	/* Number of paths with this directory */
161     int		  hits;	    	/* the number of times a file in this
162 				 * directory has been found */
163     Hash_Table    files;    	/* Hash table of files in directory */
164 } Path;
165 
166 static Path    	  *dot;	    /* contents of current directory */
167 static Hash_Table mtimes;   /* Results of doing a last-resort stat in
168 			     * Dir_FindFile -- if we have to go to the
169 			     * system to find the file, we might as well
170 			     * have its mtime on record. XXX: If this is done
171 			     * way early, there's a chance other rules will
172 			     * have already updated the file, in which case
173 			     * we'll update it again. Generally, there won't
174 			     * be two rules to update a single file, so this
175 			     * should be ok, but... */
176 
177 
178 /*-
179  *-----------------------------------------------------------------------
180  * Dir_Init --
181  *	initialize things for this module
182  *
183  * Results:
184  *	none
185  *
186  * Side Effects:
187  *	some directories may be opened.
188  *-----------------------------------------------------------------------
189  */
190 void
191 Dir_Init ()
192 {
193     dirSearchPath = Lst_Init (FALSE);
194     openDirectories = Lst_Init (FALSE);
195     Hash_InitTable(&mtimes, 0, HASH_STRING_KEYS);
196 
197     /*
198      * Since the Path structure is placed on both openDirectories and
199      * the path we give Dir_AddDir (which in this case is openDirectories),
200      * we need to remove "." from openDirectories and what better time to
201      * do it than when we have to fetch the thing anyway?
202      */
203     Dir_AddDir (openDirectories, ".");
204     dot = (Path *) Lst_DeQueue (openDirectories);
205 
206     /*
207      * We always need to have dot around, so we increment its reference count
208      * to make sure it's not destroyed.
209      */
210     dot->refCount += 1;
211 }
212 
213 /*-
214  *-----------------------------------------------------------------------
215  * DirFindName --
216  *	See if the Path structure describes the same directory as the
217  *	given one by comparing their names. Called from Dir_AddDir via
218  *	Lst_Find when searching the list of open directories.
219  *
220  * Results:
221  *	0 if it is the same. Non-zero otherwise
222  *
223  * Side Effects:
224  *	None
225  *-----------------------------------------------------------------------
226  */
227 static int
228 DirFindName (p, dname)
229     Path          *p;	      /* Current name */
230     char	  *dname;     /* Desired name */
231 {
232     return (strcmp (p->name, dname));
233 }
234 
235 /*-
236  *-----------------------------------------------------------------------
237  * Dir_HasWildcards  --
238  *	see if the given name has any wildcard characters in it
239  *
240  * Results:
241  *	returns TRUE if the word should be expanded, FALSE otherwise
242  *
243  * Side Effects:
244  *	none
245  *-----------------------------------------------------------------------
246  */
247 Boolean
248 Dir_HasWildcards (name)
249     char          *name;	/* name to check */
250 {
251     register char *cp;
252 
253     for (cp = name; *cp; cp++) {
254 	switch(*cp) {
255 	case '{':
256 	case '[':
257 	case '?':
258 	case '*':
259 	    return (TRUE);
260 	}
261     }
262     return (FALSE);
263 }
264 
265 /*-
266  *-----------------------------------------------------------------------
267  * DirMatchFiles --
268  * 	Given a pattern and a Path structure, see if any files
269  *	match the pattern and add their names to the 'expansions' list if
270  *	any do. This is incomplete -- it doesn't take care of patterns like
271  *	src/*src/*.c properly (just *.c on any of the directories), but it
272  *	will do for now.
273  *
274  * Results:
275  *	Always returns 0
276  *
277  * Side Effects:
278  *	File names are added to the expansions lst. The directory will be
279  *	fully hashed when this is done.
280  *-----------------------------------------------------------------------
281  */
282 static int
283 DirMatchFiles (pattern, p, expansions)
284     char	  *pattern;   	/* Pattern to look for */
285     Path	  *p;         	/* Directory to search */
286     Lst	    	  expansions;	/* Place to store the results */
287 {
288     Hash_Search	  search;   	/* Index into the directory's table */
289     Hash_Entry	  *entry;   	/* Current entry in the table */
290     char    	  *f;	    	/* Current entry in the directory */
291     Boolean 	  isDot;    	/* TRUE if the directory being searched is . */
292 
293     isDot = (*p->name == '.' && p->name[1] == '\0');
294 
295     for (entry = Hash_EnumFirst(&p->files, &search);
296 	 entry != (Hash_Entry *)NULL;
297 	 entry = Hash_EnumNext(&search))
298     {
299 	/*
300 	 * See if the file matches the given pattern. Note we follow the UNIX
301 	 * convention that dot files will only be found if the pattern
302 	 * begins with a dot (note also that as a side effect of the hashing
303 	 * scheme, .* won't match . or .. since they aren't hashed).
304 	 */
305 	if (Str_Match(entry->key.name, pattern) &&
306 	    ((entry->key.name[0] != '.') ||
307 	     (pattern[0] == '.')))
308 	{
309 	    (void)Lst_AtEnd(expansions,
310 			    (isDot ? strdup(entry->key.name) :
311 			     str_concat(p->name, entry->key.name,
312 					STR_ADDSLASH)));
313 	}
314     }
315     return (0);
316 }
317 
318 /*-
319  *-----------------------------------------------------------------------
320  * DirExpandCurly --
321  *	Expand curly braces like the C shell. Does this recursively.
322  *	Note the special case: if after the piece of the curly brace is
323  *	done there are no wildcard characters in the result, the result is
324  *	placed on the list WITHOUT CHECKING FOR ITS EXISTENCE.
325  *
326  * Results:
327  *	None.
328  *
329  * Side Effects:
330  *	The given list is filled with the expansions...
331  *
332  *-----------------------------------------------------------------------
333  */
334 static void
335 DirExpandCurly(word, brace, path, expansions)
336     char    	  *word;    	/* Entire word to expand */
337     char    	  *brace;   	/* First curly brace in it */
338     Lst	    	  path;	    	/* Search path to use */
339     Lst	    	  expansions;	/* Place to store the expansions */
340 {
341     char    	  *end;	    	/* Character after the closing brace */
342     char    	  *cp;	    	/* Current position in brace clause */
343     char    	  *start;   	/* Start of current piece of brace clause */
344     int	    	  bracelevel;	/* Number of braces we've seen. If we see a
345 				 * right brace when this is 0, we've hit the
346 				 * end of the clause. */
347     char    	  *file;    	/* Current expansion */
348     int	    	  otherLen; 	/* The length of the other pieces of the
349 				 * expansion (chars before and after the
350 				 * clause in 'word') */
351     char    	  *cp2;	    	/* Pointer for checking for wildcards in
352 				 * expansion before calling Dir_Expand */
353 
354     start = brace+1;
355 
356     /*
357      * Find the end of the brace clause first, being wary of nested brace
358      * clauses.
359      */
360     for (end = start, bracelevel = 0; *end != '\0'; end++) {
361 	if (*end == '{') {
362 	    bracelevel++;
363 	} else if ((*end == '}') && (bracelevel-- == 0)) {
364 	    break;
365 	}
366     }
367     if (*end == '\0') {
368 	Error("Unterminated {} clause \"%s\"", start);
369 	return;
370     } else {
371 	end++;
372     }
373     otherLen = brace - word + strlen(end);
374 
375     for (cp = start; cp < end; cp++) {
376 	/*
377 	 * Find the end of this piece of the clause.
378 	 */
379 	bracelevel = 0;
380 	while (*cp != ',') {
381 	    if (*cp == '{') {
382 		bracelevel++;
383 	    } else if ((*cp == '}') && (bracelevel-- <= 0)) {
384 		break;
385 	    }
386 	    cp++;
387 	}
388 	/*
389 	 * Allocate room for the combination and install the three pieces.
390 	 */
391 	file = emalloc(otherLen + cp - start + 1);
392 	if (brace != word) {
393 	    strncpy(file, word, brace-word);
394 	}
395 	if (cp != start) {
396 	    strncpy(&file[brace-word], start, cp-start);
397 	}
398 	strcpy(&file[(brace-word)+(cp-start)], end);
399 
400 	/*
401 	 * See if the result has any wildcards in it. If we find one, call
402 	 * Dir_Expand right away, telling it to place the result on our list
403 	 * of expansions.
404 	 */
405 	for (cp2 = file; *cp2 != '\0'; cp2++) {
406 	    switch(*cp2) {
407 	    case '*':
408 	    case '?':
409 	    case '{':
410 	    case '[':
411 		Dir_Expand(file, path, expansions);
412 		goto next;
413 	    }
414 	}
415 	if (*cp2 == '\0') {
416 	    /*
417 	     * Hit the end w/o finding any wildcards, so stick the expansion
418 	     * on the end of the list.
419 	     */
420 	    (void)Lst_AtEnd(expansions, file);
421 	} else {
422 	next:
423 	    free(file);
424 	}
425 	start = cp+1;
426     }
427 }
428 
429 
430 /*-
431  *-----------------------------------------------------------------------
432  * DirExpandInt --
433  *	Internal expand routine. Passes through the directories in the
434  *	path one by one, calling DirMatchFiles for each. NOTE: This still
435  *	doesn't handle patterns in directories...
436  *
437  * Results:
438  *	None.
439  *
440  * Side Effects:
441  *	Things are added to the expansions list.
442  *
443  *-----------------------------------------------------------------------
444  */
445 static void
446 DirExpandInt(word, path, expansions)
447     char    	  *word;    	/* Word to expand */
448     Lst	    	  path;	    	/* Path on which to look */
449     Lst	    	  expansions;	/* Place to store the result */
450 {
451     LstNode 	  ln;	    	/* Current node */
452     Path	  *p;	    	/* Directory in the node */
453 
454     if (Lst_Open(path) == SUCCESS) {
455 	while ((ln = Lst_Next(path)) != NILLNODE) {
456 	    p = (Path *)Lst_Datum(ln);
457 	    DirMatchFiles(word, p, expansions);
458 	}
459 	Lst_Close(path);
460     }
461 }
462 
463 /*-
464  *-----------------------------------------------------------------------
465  * DirPrintWord --
466  *	Print a word in the list of expansions. Callback for Dir_Expand
467  *	when DEBUG(DIR), via Lst_ForEach.
468  *
469  * Results:
470  *	=== 0
471  *
472  * Side Effects:
473  *	The passed word is printed, followed by a space.
474  *
475  *-----------------------------------------------------------------------
476  */
477 static int
478 DirPrintWord(word)
479     char    *word;
480 {
481     printf("%s ", word);
482 
483     return(0);
484 }
485 
486 /*-
487  *-----------------------------------------------------------------------
488  * Dir_Expand  --
489  *	Expand the given word into a list of words by globbing it looking
490  *	in the directories on the given search path.
491  *
492  * Results:
493  *	A list of words consisting of the files which exist along the search
494  *	path matching the given pattern.
495  *
496  * Side Effects:
497  *	Directories may be opened. Who knows?
498  *-----------------------------------------------------------------------
499  */
500 void
501 Dir_Expand (word, path, expansions)
502     char    *word;      /* the word to expand */
503     Lst     path;   	/* the list of directories in which to find
504 			 * the resulting files */
505     Lst	    expansions;	/* the list on which to place the results */
506 {
507     char    	  *cp;
508 
509     if (DEBUG(DIR)) {
510 	printf("expanding \"%s\"...", word);
511     }
512 
513     cp = index(word, '{');
514     if (cp) {
515 	DirExpandCurly(word, cp, path, expansions);
516     } else {
517 	cp = index(word, '/');
518 	if (cp) {
519 	    /*
520 	     * The thing has a directory component -- find the first wildcard
521 	     * in the string.
522 	     */
523 	    for (cp = word; *cp; cp++) {
524 		if (*cp == '?' || *cp == '[' || *cp == '*' || *cp == '{') {
525 		    break;
526 		}
527 	    }
528 	    if (*cp == '{') {
529 		/*
530 		 * This one will be fun.
531 		 */
532 		DirExpandCurly(word, cp, path, expansions);
533 		return;
534 	    } else if (*cp != '\0') {
535 		/*
536 		 * Back up to the start of the component
537 		 */
538 		char  *dirpath;
539 
540 		while (cp > word && *cp != '/') {
541 		    cp--;
542 		}
543 		if (cp != word) {
544 		    /*
545 		     * If the glob isn't in the first component, try and find
546 		     * all the components up to the one with a wildcard.
547 		     */
548 		    *cp = '\0';
549 		    dirpath = Dir_FindFile(word, path);
550 		    *cp = '/';
551 		    /*
552 		     * dirpath is null if can't find the leading component
553 		     * XXX: Dir_FindFile won't find internal components.
554 		     * i.e. if the path contains ../Etc/Object and we're
555 		     * looking for Etc, it won't be found. Ah well.
556 		     * Probably not important.
557 		     */
558 		    if (dirpath != (char *)NULL) {
559 			path = Lst_Init(FALSE);
560 			Dir_AddDir(path, dirpath);
561 			DirExpandInt(cp+1, path, expansions);
562 			Lst_Destroy(path, NOFREE);
563 		    }
564 		} else {
565 		    /*
566 		     * Start the search from the local directory
567 		     */
568 		    DirExpandInt(word, path, expansions);
569 		}
570 	    } else {
571 		/*
572 		 * Return the file -- this should never happen.
573 		 */
574 		DirExpandInt(word, path, expansions);
575 	    }
576 	} else {
577 	    /*
578 	     * First the files in dot
579 	     */
580 	    DirMatchFiles(word, dot, expansions);
581 
582 	    /*
583 	     * Then the files in every other directory on the path.
584 	     */
585 	    DirExpandInt(word, path, expansions);
586 	}
587     }
588     if (DEBUG(DIR)) {
589 	Lst_ForEach(expansions, DirPrintWord, NULL);
590 	putchar('\n');
591     }
592 }
593 
594 /*-
595  *-----------------------------------------------------------------------
596  * Dir_FindFile  --
597  *	Find the file with the given name along the given search path.
598  *
599  * Results:
600  *	The path to the file or NULL. This path is guaranteed to be in a
601  *	different part of memory than name and so may be safely free'd.
602  *
603  * Side Effects:
604  *	If the file is found in a directory which is not on the path
605  *	already (either 'name' is absolute or it is a relative path
606  *	[ dir1/.../dirn/file ] which exists below one of the directories
607  *	already on the search path), its directory is added to the end
608  *	of the path on the assumption that there will be more files in
609  *	that directory later on. Sometimes this is true. Sometimes not.
610  *-----------------------------------------------------------------------
611  */
612 char *
613 Dir_FindFile (name, path)
614     char    	  *name;    /* the file to find */
615     Lst           path;	    /* the Lst of directories to search */
616 {
617     register char *p1;	    /* pointer into p->name */
618     register char *p2;	    /* pointer into name */
619     LstNode       ln;	    /* a list element */
620     register char *file;    /* the current filename to check */
621     register Path *p;	    /* current path member */
622     register char *cp;	    /* index of first slash, if any */
623     Boolean	  hasSlash; /* true if 'name' contains a / */
624     struct stat	  stb;	    /* Buffer for stat, if necessary */
625     Hash_Entry	  *entry;   /* Entry for mtimes table */
626 
627     /*
628      * Find the final component of the name and note whether it has a
629      * slash in it (the name, I mean)
630      */
631     cp = rindex (name, '/');
632     if (cp) {
633 	hasSlash = TRUE;
634 	cp += 1;
635     } else {
636 	hasSlash = FALSE;
637 	cp = name;
638     }
639 
640     if (DEBUG(DIR)) {
641 	printf("Searching for %s...", name);
642     }
643     /*
644      * No matter what, we always look for the file in the current directory
645      * before anywhere else and we *do not* add the ./ to it if it exists.
646      * This is so there are no conflicts between what the user specifies
647      * (fish.c) and what pmake finds (./fish.c).
648      */
649     if ((!hasSlash || (cp - name == 2 && *name == '.')) &&
650 	(Hash_FindEntry (&dot->files, (Address)cp) != (Hash_Entry *)NULL)) {
651 	    if (DEBUG(DIR)) {
652 		printf("in '.'\n");
653 	    }
654 	    hits += 1;
655 	    dot->hits += 1;
656 	    return (strdup (name));
657     }
658 
659     if (Lst_Open (path) == FAILURE) {
660 	if (DEBUG(DIR)) {
661 	    printf("couldn't open path, file not found\n");
662 	}
663 	misses += 1;
664 	return ((char *) NULL);
665     }
666 
667     /*
668      * We look through all the directories on the path seeking one which
669      * contains the final component of the given name and whose final
670      * component(s) match the name's initial component(s). If such a beast
671      * is found, we concatenate the directory name and the final component
672      * and return the resulting string. If we don't find any such thing,
673      * we go on to phase two...
674      */
675     while ((ln = Lst_Next (path)) != NILLNODE) {
676 	p = (Path *) Lst_Datum (ln);
677 	if (DEBUG(DIR)) {
678 	    printf("%s...", p->name);
679 	}
680 	if (Hash_FindEntry (&p->files, (Address)cp) != (Hash_Entry *)NULL) {
681 	    if (DEBUG(DIR)) {
682 		printf("here...");
683 	    }
684 	    if (hasSlash) {
685 		/*
686 		 * If the name had a slash, its initial components and p's
687 		 * final components must match. This is false if a mismatch
688 		 * is encountered before all of the initial components
689 		 * have been checked (p2 > name at the end of the loop), or
690 		 * we matched only part of one of the components of p
691 		 * along with all the rest of them (*p1 != '/').
692 		 */
693 		p1 = p->name + strlen (p->name) - 1;
694 		p2 = cp - 2;
695 		while (p2 >= name && *p1 == *p2) {
696 		    p1 -= 1; p2 -= 1;
697 		}
698 		if (p2 >= name || (p1 >= p->name && *p1 != '/')) {
699 		    if (DEBUG(DIR)) {
700 			printf("component mismatch -- continuing...");
701 		    }
702 		    continue;
703 		}
704 	    }
705 	    file = str_concat (p->name, cp, STR_ADDSLASH);
706 	    if (DEBUG(DIR)) {
707 		printf("returning %s\n", file);
708 	    }
709 	    Lst_Close (path);
710 	    p->hits += 1;
711 	    hits += 1;
712 	    return (file);
713 	} else if (hasSlash) {
714 	    /*
715 	     * If the file has a leading path component and that component
716 	     * exactly matches the entire name of the current search
717 	     * directory, we assume the file doesn't exist and return NULL.
718 	     */
719 	    for (p1 = p->name, p2 = name; *p1 && *p1 == *p2; p1++, p2++) {
720 		continue;
721 	    }
722 	    if (*p1 == '\0' && p2 == cp - 1) {
723 		if (DEBUG(DIR)) {
724 		    printf("must be here but isn't -- returing NULL\n");
725 		}
726 		Lst_Close (path);
727 		return ((char *) NULL);
728 	    }
729 	}
730     }
731 
732     /*
733      * We didn't find the file on any existing members of the directory.
734      * If the name doesn't contain a slash, that means it doesn't exist.
735      * If it *does* contain a slash, however, there is still hope: it
736      * could be in a subdirectory of one of the members of the search
737      * path. (eg. /usr/include and sys/types.h. The above search would
738      * fail to turn up types.h in /usr/include, but it *is* in
739      * /usr/include/sys/types.h) If we find such a beast, we assume there
740      * will be more (what else can we assume?) and add all but the last
741      * component of the resulting name onto the search path (at the
742      * end). This phase is only performed if the file is *not* absolute.
743      */
744     if (!hasSlash) {
745 	if (DEBUG(DIR)) {
746 	    printf("failed.\n");
747 	}
748 	misses += 1;
749 	return ((char *) NULL);
750     }
751 
752     if (*name != '/') {
753 	Boolean	checkedDot = FALSE;
754 
755 	if (DEBUG(DIR)) {
756 	    printf("failed. Trying subdirectories...");
757 	}
758 	(void) Lst_Open (path);
759 	while ((ln = Lst_Next (path)) != NILLNODE) {
760 	    p = (Path *) Lst_Datum (ln);
761 	    if (p != dot) {
762 		file = str_concat (p->name, name, STR_ADDSLASH);
763 	    } else {
764 		/*
765 		 * Checking in dot -- DON'T put a leading ./ on the thing.
766 		 */
767 		file = strdup(name);
768 		checkedDot = TRUE;
769 	    }
770 	    if (DEBUG(DIR)) {
771 		printf("checking %s...", file);
772 	    }
773 
774 
775 	    if (stat (file, &stb) == 0) {
776 		if (DEBUG(DIR)) {
777 		    printf("got it.\n");
778 		}
779 
780 		Lst_Close (path);
781 
782 		/*
783 		 * We've found another directory to search. We know there's
784 		 * a slash in 'file' because we put one there. We nuke it after
785 		 * finding it and call Dir_AddDir to add this new directory
786 		 * onto the existing search path. Once that's done, we restore
787 		 * the slash and triumphantly return the file name, knowing
788 		 * that should a file in this directory every be referenced
789 		 * again in such a manner, we will find it without having to do
790 		 * numerous numbers of access calls. Hurrah!
791 		 */
792 		cp = rindex (file, '/');
793 		*cp = '\0';
794 		Dir_AddDir (path, file);
795 		*cp = '/';
796 
797 		/*
798 		 * Save the modification time so if it's needed, we don't have
799 		 * to fetch it again.
800 		 */
801 		if (DEBUG(DIR)) {
802 		    printf("Caching %s for %s\n", Targ_FmtTime(stb.st_mtime),
803 			    file);
804 		}
805 		entry = Hash_CreateEntry(&mtimes, (ClientData)file,
806 					 (Boolean *)NULL);
807 		Hash_SetValue(entry, stb.st_mtime);
808 		nearmisses += 1;
809 		return (file);
810 	    } else {
811 		free (file);
812 	    }
813 	}
814 
815 	if (DEBUG(DIR)) {
816 	    printf("failed. ");
817 	}
818 	Lst_Close (path);
819 
820 	if (checkedDot) {
821 	    /*
822 	     * Already checked by the given name, since . was in the path,
823 	     * so no point in proceeding...
824 	     */
825 	    if (DEBUG(DIR)) {
826 		printf("Checked . already, returning NULL\n");
827 	    }
828 	    return(NULL);
829 	}
830     }
831 
832     /*
833      * Didn't find it that way, either. Sigh. Phase 3. Add its directory
834      * onto the search path in any case, just in case, then look for the
835      * thing in the hash table. If we find it, grand. We return a new
836      * copy of the name. Otherwise we sadly return a NULL pointer. Sigh.
837      * Note that if the directory holding the file doesn't exist, this will
838      * do an extra search of the final directory on the path. Unless something
839      * weird happens, this search won't succeed and life will be groovy.
840      *
841      * Sigh. We cannot add the directory onto the search path because
842      * of this amusing case:
843      * $(INSTALLDIR)/$(FILE): $(FILE)
844      *
845      * $(FILE) exists in $(INSTALLDIR) but not in the current one.
846      * When searching for $(FILE), we will find it in $(INSTALLDIR)
847      * b/c we added it here. This is not good...
848      */
849 #ifdef notdef
850     cp[-1] = '\0';
851     Dir_AddDir (path, name);
852     cp[-1] = '/';
853 
854     bigmisses += 1;
855     ln = Lst_Last (path);
856     if (ln == NILLNODE) {
857 	return ((char *) NULL);
858     } else {
859 	p = (Path *) Lst_Datum (ln);
860     }
861 
862     if (Hash_FindEntry (&p->files, (Address)cp) != (Hash_Entry *)NULL) {
863 	return (strdup (name));
864     } else {
865 	return ((char *) NULL);
866     }
867 #else /* !notdef */
868     if (DEBUG(DIR)) {
869 	printf("Looking for \"%s\"...", name);
870     }
871 
872     bigmisses += 1;
873     entry = Hash_FindEntry(&mtimes, name);
874     if (entry != (Hash_Entry *)NULL) {
875 	if (DEBUG(DIR)) {
876 	    printf("got it (in mtime cache)\n");
877 	}
878 	return(strdup(name));
879     } else if (stat (name, &stb) == 0) {
880 	entry = Hash_CreateEntry(&mtimes, name, (Boolean *)NULL);
881 	if (DEBUG(DIR)) {
882 	    printf("Caching %s for %s\n", Targ_FmtTime(stb.st_mtime),
883 		    name);
884 	}
885 	Hash_SetValue(entry, stb.st_mtime);
886 	return (strdup (name));
887     } else {
888 	if (DEBUG(DIR)) {
889 	    printf("failed. Returning NULL\n");
890 	}
891 	return ((char *)NULL);
892     }
893 #endif /* notdef */
894 }
895 
896 /*-
897  *-----------------------------------------------------------------------
898  * Dir_MTime  --
899  *	Find the modification time of the file described by gn along the
900  *	search path dirSearchPath.
901  *
902  * Results:
903  *	The modification time or 0 if it doesn't exist
904  *
905  * Side Effects:
906  *	The modification time is placed in the node's mtime slot.
907  *	If the node didn't have a path entry before, and Dir_FindFile
908  *	found one for it, the full name is placed in the path slot.
909  *-----------------------------------------------------------------------
910  */
911 int
912 Dir_MTime (gn)
913     GNode         *gn;	      /* the file whose modification time is
914 			       * desired */
915 {
916     char          *fullName;  /* the full pathname of name */
917     struct stat	  stb;	      /* buffer for finding the mod time */
918     Hash_Entry	  *entry;
919 
920     if (gn->type & OP_ARCHV) {
921 	return Arch_MTime (gn);
922     } else if (gn->path == (char *)NULL) {
923 	fullName = Dir_FindFile (gn->name, dirSearchPath);
924     } else {
925 	fullName = gn->path;
926     }
927 
928     if (fullName == (char *)NULL) {
929 	fullName = gn->name;
930     }
931 
932     entry = Hash_FindEntry(&mtimes, fullName);
933     if (entry != (Hash_Entry *)NULL) {
934 	/*
935 	 * Only do this once -- the second time folks are checking to
936 	 * see if the file was actually updated, so we need to actually go
937 	 * to the file system.
938 	 */
939 	if (DEBUG(DIR)) {
940 	    printf("Using cached time %s for %s\n",
941 		    Targ_FmtTime(Hash_GetValue(entry)), fullName);
942 	}
943 	stb.st_mtime = (time_t)Hash_GetValue(entry);
944 	Hash_DeleteEntry(&mtimes, entry);
945     } else if (stat (fullName, &stb) < 0) {
946 	if (gn->type & OP_MEMBER) {
947 	    return Arch_MemMTime (gn);
948 	} else {
949 	    stb.st_mtime = 0;
950 	}
951     }
952     if (fullName && gn->path == (char *)NULL) {
953 	gn->path = fullName;
954     }
955 
956     gn->mtime = stb.st_mtime;
957     return (gn->mtime);
958 }
959 
960 /*-
961  *-----------------------------------------------------------------------
962  * Dir_AddDir --
963  *	Add the given name to the end of the given path. The order of
964  *	the arguments is backwards so ParseDoDependency can do a
965  *	Lst_ForEach of its list of paths...
966  *
967  * Results:
968  *	none
969  *
970  * Side Effects:
971  *	A structure is added to the list and the directory is
972  *	read and hashed.
973  *-----------------------------------------------------------------------
974  */
975 void
976 Dir_AddDir (path, name)
977     Lst           path;	      /* the path to which the directory should be
978 			       * added */
979     char          *name;      /* the name of the directory to add */
980 {
981     LstNode       ln;	      /* node in case Path structure is found */
982     register Path *p;	      /* pointer to new Path structure */
983     DIR     	  *d;	      /* for reading directory */
984     register struct direct *dp; /* entry in directory */
985     Hash_Entry	  *he;
986     char	  *fName;
987 
988     ln = Lst_Find (openDirectories, (ClientData)name, DirFindName);
989     if (ln != NILLNODE) {
990 	p = (Path *)Lst_Datum (ln);
991 	if (Lst_Member(path, (ClientData)p) == NILLNODE) {
992 	    p->refCount += 1;
993 	    (void)Lst_AtEnd (path, (ClientData)p);
994 	}
995     } else {
996 	if (DEBUG(DIR)) {
997 	    printf("Caching %s...", name);
998 	    fflush(stdout);
999 	}
1000 
1001 	if ((d = opendir (name)) != (DIR *) NULL) {
1002 	    p = (Path *) emalloc (sizeof (Path));
1003 	    p->name = strdup (name);
1004 	    p->hits = 0;
1005 	    p->refCount = 1;
1006 	    Hash_InitTable (&p->files, -1, HASH_STRING_KEYS);
1007 
1008 	    /*
1009 	     * Skip the first two entries -- these will *always* be . and ..
1010 	     */
1011 	    (void)readdir(d);
1012 	    (void)readdir(d);
1013 
1014 	    while ((dp = readdir (d)) != (struct direct *) NULL) {
1015 #ifdef sun
1016 		/*
1017 		 * The sun directory library doesn't check for a 0 inode
1018 		 * (0-inode slots just take up space), so we have to do
1019 		 * it ourselves.
1020 		 */
1021 		if (dp->d_fileno == 0) {
1022 		    continue;
1023 		}
1024 #endif sun
1025 		(void)Hash_CreateEntry(&p->files, dp->d_name, (Boolean *)NULL);
1026 	    }
1027 	    (void) closedir (d);
1028 	    (void)Lst_AtEnd (openDirectories, (ClientData)p);
1029 	    (void)Lst_AtEnd (path, (ClientData)p);
1030 	}
1031 	if (DEBUG(DIR)) {
1032 	    printf("done\n");
1033 	}
1034     }
1035 }
1036 
1037 /*-
1038  *-----------------------------------------------------------------------
1039  * Dir_CopyDir --
1040  *	Callback function for duplicating a search path via Lst_Duplicate.
1041  *	Ups the reference count for the directory.
1042  *
1043  * Results:
1044  *	Returns the Path it was given.
1045  *
1046  * Side Effects:
1047  *	The refCount of the path is incremented.
1048  *
1049  *-----------------------------------------------------------------------
1050  */
1051 ClientData
1052 Dir_CopyDir(p)
1053     Path    *p;	  	/* Directory descriptor to copy */
1054 {
1055     p->refCount += 1;
1056 
1057     return ((ClientData)p);
1058 }
1059 
1060 /*-
1061  *-----------------------------------------------------------------------
1062  * Dir_MakeFlags --
1063  *	Make a string by taking all the directories in the given search
1064  *	path and preceding them by the given flag. Used by the suffix
1065  *	module to create variables for compilers based on suffix search
1066  *	paths.
1067  *
1068  * Results:
1069  *	The string mentioned above. Note that there is no space between
1070  *	the given flag and each directory. The empty string is returned if
1071  *	Things don't go well.
1072  *
1073  * Side Effects:
1074  *	None
1075  *-----------------------------------------------------------------------
1076  */
1077 char *
1078 Dir_MakeFlags (flag, path)
1079     char	  *flag;  /* flag which should precede each directory */
1080     Lst	    	  path;	  /* list of directories */
1081 {
1082     char	  *str;	  /* the string which will be returned */
1083     char	  *tstr;  /* the current directory preceded by 'flag' */
1084     LstNode	  ln;	  /* the node of the current directory */
1085     Path	  *p;	  /* the structure describing the current directory */
1086 
1087     str = strdup ("");
1088 
1089     if (Lst_Open (path) == SUCCESS) {
1090 	while ((ln = Lst_Next (path)) != NILLNODE) {
1091 	    p = (Path *) Lst_Datum (ln);
1092 	    tstr = str_concat (flag, p->name, 0);
1093 	    str = str_concat (str, tstr, STR_ADDSPACE | STR_DOFREE);
1094 	}
1095 	Lst_Close (path);
1096     }
1097 
1098     return (str);
1099 }
1100 
1101 /*-
1102  *-----------------------------------------------------------------------
1103  * Dir_Destroy --
1104  *	Nuke a directory descriptor, if possible. Callback procedure
1105  *	for the suffixes module when destroying a search path.
1106  *
1107  * Results:
1108  *	None.
1109  *
1110  * Side Effects:
1111  *	If no other path references this directory (refCount == 0),
1112  *	the Path and all its data are freed.
1113  *
1114  *-----------------------------------------------------------------------
1115  */
1116 void
1117 Dir_Destroy (p)
1118     Path    	  *p;	    /* The directory descriptor to nuke */
1119 {
1120     Hash_Search	  thing1;
1121     Hash_Entry	  *thing2;
1122 
1123     p->refCount -= 1;
1124 
1125     if (p->refCount == 0) {
1126 	LstNode	ln;
1127 
1128 	ln = Lst_Member (openDirectories, (ClientData)p);
1129 	(void) Lst_Remove (openDirectories, ln);
1130 
1131 	Hash_DeleteTable (&p->files);
1132 	free((Address)p->name);
1133 	free((Address)p);
1134     }
1135 }
1136 
1137 /*-
1138  *-----------------------------------------------------------------------
1139  * Dir_ClearPath --
1140  *	Clear out all elements of the given search path. This is different
1141  *	from destroying the list, notice.
1142  *
1143  * Results:
1144  *	None.
1145  *
1146  * Side Effects:
1147  *	The path is set to the empty list.
1148  *
1149  *-----------------------------------------------------------------------
1150  */
1151 void
1152 Dir_ClearPath(path)
1153     Lst	    path; 	/* Path to clear */
1154 {
1155     Path    *p;
1156     while (!Lst_IsEmpty(path)) {
1157 	p = (Path *)Lst_DeQueue(path);
1158 	Dir_Destroy(p);
1159     }
1160 }
1161 
1162 
1163 /*-
1164  *-----------------------------------------------------------------------
1165  * Dir_Concat --
1166  *	Concatenate two paths, adding the second to the end of the first.
1167  *	Makes sure to avoid duplicates.
1168  *
1169  * Results:
1170  *	None
1171  *
1172  * Side Effects:
1173  *	Reference counts for added dirs are upped.
1174  *
1175  *-----------------------------------------------------------------------
1176  */
1177 void
1178 Dir_Concat(path1, path2)
1179     Lst	    path1;  	/* Dest */
1180     Lst	    path2;  	/* Source */
1181 {
1182     LstNode ln;
1183     Path    *p;
1184 
1185     for (ln = Lst_First(path2); ln != NILLNODE; ln = Lst_Succ(ln)) {
1186 	p = (Path *)Lst_Datum(ln);
1187 	if (Lst_Member(path1, (ClientData)p) == NILLNODE) {
1188 	    p->refCount += 1;
1189 	    (void)Lst_AtEnd(path1, (ClientData)p);
1190 	}
1191     }
1192 }
1193 
1194 /********** DEBUG INFO **********/
1195 Dir_PrintDirectories()
1196 {
1197     LstNode	ln;
1198     Path	*p;
1199 
1200     printf ("#*** Directory Cache:\n");
1201     printf ("# Stats: %d hits %d misses %d near misses %d losers (%d%%)\n",
1202 	      hits, misses, nearmisses, bigmisses,
1203 	      (hits+bigmisses+nearmisses ?
1204 	       hits * 100 / (hits + bigmisses + nearmisses) : 0));
1205     printf ("# %-20s referenced\thits\n", "directory");
1206     if (Lst_Open (openDirectories) == SUCCESS) {
1207 	while ((ln = Lst_Next (openDirectories)) != NILLNODE) {
1208 	    p = (Path *) Lst_Datum (ln);
1209 	    printf ("# %-20s %10d\t%4d\n", p->name, p->refCount, p->hits);
1210 	}
1211 	Lst_Close (openDirectories);
1212     }
1213 }
1214 
1215 static int DirPrintDir (p) Path *p; { printf ("%s ", p->name); return (0); }
1216 
1217 Dir_PrintPath (path)
1218     Lst	path;
1219 {
1220     Lst_ForEach (path, DirPrintDir, (ClientData)0);
1221 }
1222