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dir.c revision 1.184
      1 /*	$NetBSD: dir.c,v 1.184 2020/10/25 09:19:10 rillig 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 /*-
     73  * dir.c --
     74  *	Directory searching using wildcards and/or normal names...
     75  *	Used both for source wildcarding in the Makefile and for finding
     76  *	implicit sources.
     77  *
     78  * The interface for this module is:
     79  *	Dir_Init	Initialize the module.
     80  *
     81  *	Dir_InitCur	Set the cur CachedDir.
     82  *
     83  *	Dir_InitDot	Set the dot CachedDir.
     84  *
     85  *	Dir_End		Clean up the module.
     86  *
     87  *	Dir_SetPATH	Set ${.PATH} to reflect state of dirSearchPath.
     88  *
     89  *	Dir_HasWildcards
     90  *			Returns TRUE if the name given it needs to
     91  *			be wildcard-expanded.
     92  *
     93  *	Dir_Expand	Given a pattern and a path, return a Lst of names
     94  *			which match the pattern on the search path.
     95  *
     96  *	Dir_FindFile	Searches for a file on a given search path.
     97  *			If it exists, the entire path is returned.
     98  *			Otherwise NULL is returned.
     99  *
    100  *	Dir_FindHereOrAbove
    101  *			Search for a path in the current directory and
    102  *			then all the directories above it in turn until
    103  *			the path is found or we reach the root ("/").
    104  *
    105  *	Dir_MTime	Return the modification time of a node. The file
    106  *			is searched for along the default search path.
    107  *			The path and mtime fields of the node are filled in.
    108  *
    109  *	Dir_AddDir	Add a directory to a search path.
    110  *
    111  *	Dir_MakeFlags	Given a search path and a command flag, create
    112  *			a string with each of the directories in the path
    113  *			preceded by the command flag and all of them
    114  *			separated by a space.
    115  *
    116  *	Dir_Destroy	Destroy an element of a search path. Frees up all
    117  *			things that can be freed for the element as long
    118  *			as the element is no longer referenced by any other
    119  *			search path.
    120  *
    121  *	Dir_ClearPath	Resets a search path to the empty list.
    122  *
    123  * For debugging:
    124  *	Dir_PrintDirectories	Print stats about the directory cache.
    125  */
    126 
    127 #include <sys/types.h>
    128 #include <sys/stat.h>
    129 
    130 #include <dirent.h>
    131 #include <errno.h>
    132 
    133 #include "make.h"
    134 #include "dir.h"
    135 #include "job.h"
    136 
    137 /*	"@(#)dir.c	8.2 (Berkeley) 1/2/94"	*/
    138 MAKE_RCSID("$NetBSD: dir.c,v 1.184 2020/10/25 09:19:10 rillig Exp $");
    139 
    140 #define DIR_DEBUG0(text) DEBUG0(DIR, text)
    141 #define DIR_DEBUG1(fmt, arg1) DEBUG1(DIR, fmt, arg1)
    142 #define DIR_DEBUG2(fmt, arg1, arg2) DEBUG2(DIR, fmt, arg1, arg2)
    143 
    144 /*
    145  *	A search path consists of a list of CachedDir structures. A CachedDir
    146  *	has in it the name of the directory and a hash table of all the files
    147  *	in the directory. This is used to cut down on the number of system
    148  *	calls necessary to find implicit dependents and their like. Since
    149  *	these searches are made before any actions are taken, we need not
    150  *	worry about the directory changing due to creation commands. If this
    151  *	hampers the style of some makefiles, they must be changed.
    152  *
    153  *	A list of all previously-read directories is kept in the
    154  *	openDirectories Lst. This list is checked first before a directory
    155  *	is opened.
    156  *
    157  *	The need for the caching of whole directories is brought about by
    158  *	the multi-level transformation code in suff.c, which tends to search
    159  *	for far more files than regular make does. In the initial
    160  *	implementation, the amount of time spent performing "stat" calls was
    161  *	truly astronomical. The problem with hashing at the start is,
    162  *	of course, that pmake doesn't then detect changes to these directories
    163  *	during the course of the make. Three possibilities suggest themselves:
    164  *
    165  *	    1) just use stat to test for a file's existence. As mentioned
    166  *	       above, this is very inefficient due to the number of checks
    167  *	       engendered by the multi-level transformation code.
    168  *	    2) use readdir() and company to search the directories, keeping
    169  *	       them open between checks. I have tried this and while it
    170  *	       didn't slow down the process too much, it could severely
    171  *	       affect the amount of parallelism available as each directory
    172  *	       open would take another file descriptor out of play for
    173  *	       handling I/O for another job. Given that it is only recently
    174  *	       that UNIX OS's have taken to allowing more than 20 or 32
    175  *	       file descriptors for a process, this doesn't seem acceptable
    176  *	       to me.
    177  *	    3) record the mtime of the directory in the CachedDir structure and
    178  *	       verify the directory hasn't changed since the contents were
    179  *	       hashed. This will catch the creation or deletion of files,
    180  *	       but not the updating of files. However, since it is the
    181  *	       creation and deletion that is the problem, this could be
    182  *	       a good thing to do. Unfortunately, if the directory (say ".")
    183  *	       were fairly large and changed fairly frequently, the constant
    184  *	       rehashing could seriously degrade performance. It might be
    185  *	       good in such cases to keep track of the number of rehashes
    186  *	       and if the number goes over a (small) limit, resort to using
    187  *	       stat in its place.
    188  *
    189  *	An additional thing to consider is that pmake is used primarily
    190  *	to create C programs and until recently pcc-based compilers refused
    191  *	to allow you to specify where the resulting object file should be
    192  *	placed. This forced all objects to be created in the current
    193  *	directory. This isn't meant as a full excuse, just an explanation of
    194  *	some of the reasons for the caching used here.
    195  *
    196  *	One more note: the location of a target's file is only performed
    197  *	on the downward traversal of the graph and then only for terminal
    198  *	nodes in the graph. This could be construed as wrong in some cases,
    199  *	but prevents inadvertent modification of files when the "installed"
    200  *	directory for a file is provided in the search path.
    201  *
    202  *	Another data structure maintained by this module is an mtime
    203  *	cache used when the searching of cached directories fails to find
    204  *	a file. In the past, Dir_FindFile would simply perform an access()
    205  *	call in such a case to determine if the file could be found using
    206  *	just the name given. When this hit, however, all that was gained
    207  *	was the knowledge that the file existed. Given that an access() is
    208  *	essentially a stat() without the copyout() call, and that the same
    209  *	filesystem overhead would have to be incurred in Dir_MTime, it made
    210  *	sense to replace the access() with a stat() and record the mtime
    211  *	in a cache for when Dir_MTime was actually called.
    212  */
    213 
    214 typedef List CachedDirList;
    215 typedef ListNode CachedDirListNode;
    216 
    217 typedef ListNode SearchPathNode;
    218 
    219 SearchPath *dirSearchPath;		/* main search path */
    220 
    221 /* A list of cached directories, with fast lookup by directory name. */
    222 typedef struct OpenDirs {
    223     CachedDirList *list;
    224     HashTable /* of CachedDirListNode */ table;
    225 } OpenDirs;
    226 
    227 static void
    228 OpenDirs_Init(OpenDirs *odirs)
    229 {
    230     odirs->list = Lst_New();
    231     Hash_InitTable(&odirs->table);
    232 }
    233 
    234 #ifdef CLEANUP
    235 static void
    236 OpenDirs_Done(OpenDirs *odirs)
    237 {
    238     CachedDirListNode *ln = odirs->list->first;
    239     while (ln != NULL) {
    240 	CachedDirListNode *next = ln->next;
    241 	CachedDir *dir = ln->datum;
    242 	Dir_Destroy(dir);	/* removes the dir from odirs->list */
    243 	ln = next;
    244     }
    245     Lst_Free(odirs->list);
    246     Hash_DeleteTable(&odirs->table);
    247 }
    248 #endif
    249 
    250 static CachedDir *
    251 OpenDirs_Find(OpenDirs *odirs, const char *name)
    252 {
    253     CachedDirListNode *ln = Hash_FindValue(&odirs->table, name);
    254     return ln != NULL ? ln->datum : NULL;
    255 }
    256 
    257 static void
    258 OpenDirs_Add(OpenDirs *odirs, CachedDir *cdir)
    259 {
    260     HashEntry *he = Hash_FindEntry(&odirs->table, cdir->name);
    261     if (he != NULL)
    262 	return;
    263     he = Hash_CreateEntry(&odirs->table, cdir->name, NULL);
    264     Lst_Append(odirs->list, cdir);
    265     Hash_SetValue(he, odirs->list->last);
    266 }
    267 
    268 static void
    269 OpenDirs_Remove(OpenDirs *odirs, const char *name)
    270 {
    271     HashEntry *he = Hash_FindEntry(&odirs->table, name);
    272     CachedDirListNode *ln;
    273     if (he == NULL)
    274 	return;
    275     ln = Hash_GetValue(he);
    276     Hash_DeleteEntry(&odirs->table, he);
    277     Lst_Remove(odirs->list, ln);
    278 }
    279 
    280 static OpenDirs openDirs;	/* the list of all open directories */
    281 
    282 /*
    283  * Variables for gathering statistics on the efficiency of the hashing
    284  * mechanism.
    285  */
    286 static int hits;		/* Found in directory cache */
    287 static int misses;		/* Sad, but not evil misses */
    288 static int nearmisses;		/* Found under search path */
    289 static int bigmisses;		/* Sought by itself */
    290 
    291 static CachedDir *dot;		/* contents of current directory */
    292 static CachedDir *cur;		/* contents of current directory, if not dot */
    293 static CachedDir *dotLast;	/* a fake path entry indicating we need to
    294 				 * look for . last */
    295 
    296 /* Results of doing a last-resort stat in Dir_FindFile -- if we have to go to
    297  * the system to find the file, we might as well have its mtime on record.
    298  *
    299  * XXX: If this is done way early, there's a chance other rules will have
    300  * already updated the file, in which case we'll update it again. Generally,
    301  * there won't be two rules to update a single file, so this should be ok,
    302  * but... */
    303 static HashTable mtimes;
    304 
    305 static HashTable lmtimes;	/* same as mtimes but for lstat */
    306 
    307 /*
    308  * We use stat(2) a lot, cache the results.
    309  * mtime and mode are all we care about.
    310  */
    311 struct cache_st {
    312     time_t lmtime;		/* lstat */
    313     time_t mtime;		/* stat */
    314     mode_t mode;
    315 };
    316 
    317 /* minimize changes below */
    318 typedef enum CachedStatsFlags {
    319     CST_LSTAT = 0x01,		/* call lstat(2) instead of stat(2) */
    320     CST_UPDATE = 0x02		/* ignore existing cached entry */
    321 } CachedStatsFlags;
    322 
    323 /* Returns 0 and the result of stat(2) or lstat(2) in *mst, or -1 on error. */
    324 static int
    325 cached_stats(HashTable *htp, const char *pathname, struct make_stat *mst,
    326 	     CachedStatsFlags flags)
    327 {
    328     HashEntry *entry;
    329     struct stat sys_st;
    330     struct cache_st *cst;
    331     int rc;
    332 
    333     if (!pathname || !pathname[0])
    334 	return -1;
    335 
    336     entry = Hash_FindEntry(htp, pathname);
    337 
    338     if (entry && !(flags & CST_UPDATE)) {
    339 	cst = Hash_GetValue(entry);
    340 
    341 	mst->mst_mode = cst->mode;
    342 	mst->mst_mtime = (flags & CST_LSTAT) ? cst->lmtime : cst->mtime;
    343 	if (mst->mst_mtime) {
    344 	    DIR_DEBUG2("Using cached time %s for %s\n",
    345 		       Targ_FmtTime(mst->mst_mtime), pathname);
    346 	    return 0;
    347 	}
    348     }
    349 
    350     rc = (flags & CST_LSTAT)
    351 	 ? lstat(pathname, &sys_st)
    352 	 : stat(pathname, &sys_st);
    353     if (rc == -1)
    354 	return -1;
    355 
    356     if (sys_st.st_mtime == 0)
    357 	sys_st.st_mtime = 1;	/* avoid confusion with missing file */
    358 
    359     mst->mst_mode = sys_st.st_mode;
    360     mst->mst_mtime = sys_st.st_mtime;
    361 
    362     if (entry == NULL)
    363 	entry = Hash_CreateEntry(htp, pathname, NULL);
    364     if (Hash_GetValue(entry) == NULL) {
    365 	Hash_SetValue(entry, bmake_malloc(sizeof(*cst)));
    366 	memset(Hash_GetValue(entry), 0, sizeof(*cst));
    367     }
    368     cst = Hash_GetValue(entry);
    369     if (flags & CST_LSTAT) {
    370 	cst->lmtime = sys_st.st_mtime;
    371     } else {
    372 	cst->mtime = sys_st.st_mtime;
    373     }
    374     cst->mode = sys_st.st_mode;
    375     DIR_DEBUG2("   Caching %s for %s\n",
    376 	       Targ_FmtTime(sys_st.st_mtime), pathname);
    377 
    378     return 0;
    379 }
    380 
    381 int
    382 cached_stat(const char *pathname, struct make_stat *st)
    383 {
    384     return cached_stats(&mtimes, pathname, st, 0);
    385 }
    386 
    387 int
    388 cached_lstat(const char *pathname, struct make_stat *st)
    389 {
    390     return cached_stats(&lmtimes, pathname, st, CST_LSTAT);
    391 }
    392 
    393 /* Initialize the directories module. */
    394 void
    395 Dir_Init(void)
    396 {
    397     dirSearchPath = Lst_New();
    398     OpenDirs_Init(&openDirs);
    399     Hash_InitTable(&mtimes);
    400     Hash_InitTable(&lmtimes);
    401 }
    402 
    403 void
    404 Dir_InitDir(const char *cdname)
    405 {
    406     Dir_InitCur(cdname);
    407 
    408     dotLast = bmake_malloc(sizeof(CachedDir));
    409     dotLast->refCount = 1;
    410     dotLast->hits = 0;
    411     dotLast->name = bmake_strdup(".DOTLAST");
    412     Hash_InitTable(&dotLast->files);
    413 }
    414 
    415 /*
    416  * Called by Dir_InitDir and whenever .CURDIR is assigned to.
    417  */
    418 void
    419 Dir_InitCur(const char *cdname)
    420 {
    421     CachedDir *dir;
    422 
    423     if (cdname != NULL) {
    424 	/*
    425 	 * Our build directory is not the same as our source directory.
    426 	 * Keep this one around too.
    427 	 */
    428 	if ((dir = Dir_AddDir(NULL, cdname))) {
    429 	    dir->refCount++;
    430 	    if (cur && cur != dir) {
    431 		/*
    432 		 * We've been here before, clean up.
    433 		 */
    434 		cur->refCount--;
    435 		Dir_Destroy(cur);
    436 	    }
    437 	    cur = dir;
    438 	}
    439     }
    440 }
    441 
    442 /* (Re)initialize "dot" (current/object directory) path hash.
    443  * Some directories may be opened. */
    444 void
    445 Dir_InitDot(void)
    446 {
    447     if (dot != NULL) {
    448 	/* Remove old entry from openDirs, but do not destroy. */
    449 	OpenDirs_Remove(&openDirs, dot->name);
    450     }
    451 
    452     dot = Dir_AddDir(NULL, ".");
    453 
    454     if (dot == NULL) {
    455 	Error("Cannot open `.' (%s)", strerror(errno));
    456 	exit(1);
    457     }
    458 
    459     /*
    460      * We always need to have dot around, so we increment its reference count
    461      * to make sure it's not destroyed.
    462      */
    463     dot->refCount++;
    464     Dir_SetPATH();		/* initialize */
    465 }
    466 
    467 /* Clean up the directories module. */
    468 void
    469 Dir_End(void)
    470 {
    471 #ifdef CLEANUP
    472     if (cur) {
    473 	cur->refCount--;
    474 	Dir_Destroy(cur);
    475     }
    476     dot->refCount--;
    477     dotLast->refCount--;
    478     Dir_Destroy(dotLast);
    479     Dir_Destroy(dot);
    480     Dir_ClearPath(dirSearchPath);
    481     Lst_Free(dirSearchPath);
    482     OpenDirs_Done(&openDirs);
    483     Hash_DeleteTable(&mtimes);
    484 #endif
    485 }
    486 
    487 /*
    488  * We want ${.PATH} to indicate the order in which we will actually
    489  * search, so we rebuild it after any .PATH: target.
    490  * This is the simplest way to deal with the effect of .DOTLAST.
    491  */
    492 void
    493 Dir_SetPATH(void)
    494 {
    495     CachedDirListNode *ln;
    496     Boolean hasLastDot = FALSE;	/* true if we should search dot last */
    497 
    498     Var_Delete(".PATH", VAR_GLOBAL);
    499 
    500     if ((ln = dirSearchPath->first) != NULL) {
    501 	CachedDir *dir = ln->datum;
    502 	if (dir == dotLast) {
    503 	    hasLastDot = TRUE;
    504 	    Var_Append(".PATH", dotLast->name, VAR_GLOBAL);
    505 	}
    506     }
    507 
    508     if (!hasLastDot) {
    509 	if (dot)
    510 	    Var_Append(".PATH", dot->name, VAR_GLOBAL);
    511 	if (cur)
    512 	    Var_Append(".PATH", cur->name, VAR_GLOBAL);
    513     }
    514 
    515     for (ln = dirSearchPath->first; ln != NULL; ln = ln->next) {
    516 	CachedDir *dir = ln->datum;
    517 	if (dir == dotLast)
    518 	    continue;
    519 	if (dir == dot && hasLastDot)
    520 	    continue;
    521 	Var_Append(".PATH", dir->name, VAR_GLOBAL);
    522     }
    523 
    524     if (hasLastDot) {
    525 	if (dot)
    526 	    Var_Append(".PATH", dot->name, VAR_GLOBAL);
    527 	if (cur)
    528 	    Var_Append(".PATH", cur->name, VAR_GLOBAL);
    529     }
    530 }
    531 
    532 /* See if the given name has any wildcard characters in it. Be careful not to
    533  * expand unmatching brackets or braces.
    534  *
    535  * XXX: This code is not 100% correct ([^]] fails etc.). I really don't think
    536  * that make(1) should be expanding patterns, because then you have to set a
    537  * mechanism for escaping the expansion!
    538  *
    539  * Input:
    540  *	name		name to check
    541  *
    542  * Results:
    543  *	returns TRUE if the word should be expanded, FALSE otherwise
    544  */
    545 Boolean
    546 Dir_HasWildcards(const char *name)
    547 {
    548     const char *cp;
    549     Boolean wild = FALSE;
    550     int braces = 0, brackets = 0;
    551 
    552     for (cp = name; *cp; cp++) {
    553 	switch (*cp) {
    554 	case '{':
    555 	    braces++;
    556 	    wild = TRUE;
    557 	    break;
    558 	case '}':
    559 	    braces--;
    560 	    break;
    561 	case '[':
    562 	    brackets++;
    563 	    wild = TRUE;
    564 	    break;
    565 	case ']':
    566 	    brackets--;
    567 	    break;
    568 	case '?':
    569 	case '*':
    570 	    wild = TRUE;
    571 	    break;
    572 	default:
    573 	    break;
    574 	}
    575     }
    576     return wild && brackets == 0 && braces == 0;
    577 }
    578 
    579 /* See if any files match the pattern and add their names to the 'expansions'
    580  * list if they do.
    581  *
    582  * This is incomplete -- wildcards are only expanded in the final path
    583  * component, but not in directories like src/lib*c/file*.c, but it
    584  * will do for now (now being 1993 until at least 2020). To expand these,
    585  * use the ':sh' variable modifier such as in ${:!echo src/lib*c/file*.c!}.
    586  *
    587  * Input:
    588  *	pattern		Pattern to look for
    589  *	dir		Directory to search
    590  *	expansion	Place to store the results
    591  */
    592 static void
    593 DirMatchFiles(const char *pattern, CachedDir *dir, StringList *expansions)
    594 {
    595     const char *dirName = dir->name;
    596     Boolean isDot = dirName[0] == '.' && dirName[1] == '\0';
    597     HashIter hi;
    598 
    599     HashIter_Init(&hi, &dir->files);
    600     while (HashIter_Next(&hi) != NULL) {
    601 	const char *base = hi.entry->key;
    602 
    603 	if (!Str_Match(base, pattern))
    604 	    continue;
    605 
    606 	/*
    607 	 * Follow the UNIX convention that dot files are only found if the
    608 	 * pattern begins with a dot. The pattern '.*' does not match '.' or
    609 	 * '..' since these are not included in the directory cache.
    610 	 *
    611 	 * This means that the pattern '[a-z.]*' does not find '.file', which
    612 	 * is consistent with bash, NetBSD sh and csh.
    613 	 */
    614 	if (base[0] == '.' && pattern[0] != '.')
    615 	    continue;
    616 
    617 	{
    618 	    char *fullName = isDot
    619 			     ? bmake_strdup(base)
    620 			     : str_concat3(dirName, "/", base);
    621 	    Lst_Append(expansions, fullName);
    622 	}
    623     }
    624 }
    625 
    626 /* Find the next closing brace in the string, taking nested braces into
    627  * account. */
    628 static const char *
    629 closing_brace(const char *p)
    630 {
    631     int nest = 0;
    632     while (*p != '\0') {
    633 	if (*p == '}' && nest == 0)
    634 	    break;
    635 	if (*p == '{')
    636 	    nest++;
    637 	if (*p == '}')
    638 	    nest--;
    639 	p++;
    640     }
    641     return p;
    642 }
    643 
    644 /* Find the next closing brace or comma in the string, taking nested braces
    645  * into account. */
    646 static const char *
    647 separator_comma(const char *p)
    648 {
    649     int nest = 0;
    650     while (*p != '\0') {
    651 	if ((*p == '}' || *p == ',') && nest == 0)
    652 	    break;
    653 	if (*p == '{')
    654 	    nest++;
    655 	if (*p == '}')
    656 	    nest--;
    657 	p++;
    658     }
    659     return p;
    660 }
    661 
    662 static Boolean
    663 contains_wildcard(const char *p)
    664 {
    665     for (; *p != '\0'; p++) {
    666 	switch (*p) {
    667 	case '*':
    668 	case '?':
    669 	case '{':
    670 	case '[':
    671 	    return TRUE;
    672 	}
    673     }
    674     return FALSE;
    675 }
    676 
    677 static char *
    678 concat3(const char *a, size_t a_len, const char *b, size_t b_len,
    679 	const char *c, size_t c_len)
    680 {
    681     size_t s_len = a_len + b_len + c_len;
    682     char *s = bmake_malloc(s_len + 1);
    683     memcpy(s, a, a_len);
    684     memcpy(s + a_len, b, b_len);
    685     memcpy(s + a_len + b_len, c, c_len);
    686     s[s_len] = '\0';
    687     return s;
    688 }
    689 
    690 /* Expand curly braces like the C shell. Brace expansion by itself is purely
    691  * textual, the expansions are not looked up in the file system. But if an
    692  * expanded word contains wildcard characters, it is expanded further,
    693  * matching only the actually existing files.
    694  *
    695  * Example: "{a{b,c}}" expands to "ab" and "ac".
    696  * Example: "{a}" expands to "a".
    697  * Example: "{a,*.c}" expands to "a" and all "*.c" files that exist.
    698  *
    699  * Input:
    700  *	word		Entire word to expand
    701  *	brace		First curly brace in it
    702  *	path		Search path to use
    703  *	expansions	Place to store the expansions
    704  */
    705 static void
    706 DirExpandCurly(const char *word, const char *brace, SearchPath *path,
    707 	       StringList *expansions)
    708 {
    709     const char *prefix, *middle, *piece, *middle_end, *suffix;
    710     size_t prefix_len, suffix_len;
    711 
    712     /* Split the word into prefix '{' middle '}' suffix. */
    713 
    714     middle = brace + 1;
    715     middle_end = closing_brace(middle);
    716     if (*middle_end == '\0') {
    717 	Error("Unterminated {} clause \"%s\"", middle);
    718 	return;
    719     }
    720 
    721     prefix = word;
    722     prefix_len = (size_t)(brace - prefix);
    723     suffix = middle_end + 1;
    724     suffix_len = strlen(suffix);
    725 
    726     /* Split the middle into pieces, separated by commas. */
    727 
    728     piece = middle;
    729     while (piece < middle_end + 1) {
    730 	const char *piece_end = separator_comma(piece);
    731 	size_t piece_len = (size_t)(piece_end - piece);
    732 
    733 	char *file = concat3(prefix, prefix_len, piece, piece_len,
    734 			     suffix, suffix_len);
    735 
    736 	if (contains_wildcard(file)) {
    737 	    Dir_Expand(file, path, expansions);
    738 	    free(file);
    739 	} else {
    740 	    Lst_Append(expansions, file);
    741 	}
    742 
    743 	piece = piece_end + 1;	/* skip over the comma or closing brace */
    744     }
    745 }
    746 
    747 
    748 /* Expand the word in each of the directories from the path. */
    749 static void
    750 DirExpandPath(const char *word, SearchPath *path, StringList *expansions)
    751 {
    752     SearchPathNode *ln;
    753     for (ln = path->first; ln != NULL; ln = ln->next) {
    754 	CachedDir *dir = ln->datum;
    755 	DirMatchFiles(word, dir, expansions);
    756     }
    757 }
    758 
    759 static void
    760 PrintExpansions(StringList *expansions)
    761 {
    762     const char *sep = "";
    763     StringListNode *ln;
    764     for (ln = expansions->first; ln != NULL; ln = ln->next) {
    765 	const char *word = ln->datum;
    766 	debug_printf("%s%s", sep, word);
    767 	sep = " ";
    768     }
    769     debug_printf("\n");
    770 }
    771 
    772 /* Expand the given word into a list of words by globbing it, looking in the
    773  * directories on the given search path.
    774  *
    775  * Input:
    776  *	word		the word to expand
    777  *	path		the directories in which to find the files
    778  *	expansions	the list on which to place the results
    779  */
    780 void
    781 Dir_Expand(const char *word, SearchPath *path, StringList *expansions)
    782 {
    783     const char *cp;
    784 
    785     assert(path != NULL);
    786     assert(expansions != NULL);
    787 
    788     DIR_DEBUG1("Expanding \"%s\"... ", word);
    789 
    790     cp = strchr(word, '{');
    791     if (cp) {
    792 	DirExpandCurly(word, cp, path, expansions);
    793     } else {
    794 	cp = strchr(word, '/');
    795 	if (cp) {
    796 	    /*
    797 	     * The thing has a directory component -- find the first wildcard
    798 	     * in the string.
    799 	     */
    800 	    for (cp = word; *cp; cp++) {
    801 		if (*cp == '?' || *cp == '[' || *cp == '*' || *cp == '{') {
    802 		    break;
    803 		}
    804 	    }
    805 	    if (*cp == '{') {
    806 		/*
    807 		 * This one will be fun.
    808 		 */
    809 		DirExpandCurly(word, cp, path, expansions);
    810 		return;
    811 	    } else if (*cp != '\0') {
    812 		/*
    813 		 * Back up to the start of the component
    814 		 */
    815 		while (cp > word && *cp != '/') {
    816 		    cp--;
    817 		}
    818 		if (cp != word) {
    819 		    char *prefix = bmake_strsedup(word, cp + 1);
    820 		    /*
    821 		     * If the glob isn't in the first component, try and find
    822 		     * all the components up to the one with a wildcard.
    823 		     */
    824 		    char *dirpath = Dir_FindFile(prefix, path);
    825 		    free(prefix);
    826 		    /*
    827 		     * dirpath is null if can't find the leading component
    828 		     * XXX: Dir_FindFile won't find internal components.
    829 		     * i.e. if the path contains ../Etc/Object and we're
    830 		     * looking for Etc, it won't be found. Ah well.
    831 		     * Probably not important.
    832 		     */
    833 		    if (dirpath != NULL) {
    834 			char *dp = &dirpath[strlen(dirpath) - 1];
    835 			if (*dp == '/')
    836 			    *dp = '\0';
    837 			path = Lst_New();
    838 			(void)Dir_AddDir(path, dirpath);
    839 			DirExpandPath(cp + 1, path, expansions);
    840 			Lst_Free(path);
    841 		    }
    842 		} else {
    843 		    /*
    844 		     * Start the search from the local directory
    845 		     */
    846 		    DirExpandPath(word, path, expansions);
    847 		}
    848 	    } else {
    849 		/*
    850 		 * Return the file -- this should never happen.
    851 		 */
    852 		DirExpandPath(word, path, expansions);
    853 	    }
    854 	} else {
    855 	    /*
    856 	     * First the files in dot
    857 	     */
    858 	    DirMatchFiles(word, dot, expansions);
    859 
    860 	    /*
    861 	     * Then the files in every other directory on the path.
    862 	     */
    863 	    DirExpandPath(word, path, expansions);
    864 	}
    865     }
    866     if (DEBUG(DIR))
    867 	PrintExpansions(expansions);
    868 }
    869 
    870 /* Find if the file with the given name exists in the given path.
    871  * Return the freshly allocated path to the file, or NULL. */
    872 static char *
    873 DirLookup(CachedDir *dir, const char *base)
    874 {
    875     char *file;			/* the current filename to check */
    876 
    877     DIR_DEBUG1("   %s ...\n", dir->name);
    878 
    879     if (Hash_FindEntry(&dir->files, base) == NULL)
    880 	return NULL;
    881 
    882     file = str_concat3(dir->name, "/", base);
    883     DIR_DEBUG1("   returning %s\n", file);
    884     dir->hits++;
    885     hits++;
    886     return file;
    887 }
    888 
    889 
    890 /*-
    891  *-----------------------------------------------------------------------
    892  * DirLookupSubdir  --
    893  *	Find if the file with the given name exists in the given path.
    894  *
    895  * Results:
    896  *	The path to the file or NULL. This path is guaranteed to be in a
    897  *	different part of memory than name and so may be safely free'd.
    898  *
    899  * Side Effects:
    900  *	If the file is found, it is added in the modification times hash
    901  *	table.
    902  *-----------------------------------------------------------------------
    903  */
    904 static char *
    905 DirLookupSubdir(CachedDir *dir, const char *name)
    906 {
    907     struct make_stat mst;
    908     char *file;			/* the current filename to check */
    909 
    910     if (dir != dot) {
    911 	file = str_concat3(dir->name, "/", name);
    912     } else {
    913 	/*
    914 	 * Checking in dot -- DON'T put a leading ./ on the thing.
    915 	 */
    916 	file = bmake_strdup(name);
    917     }
    918 
    919     DIR_DEBUG1("checking %s ...\n", file);
    920 
    921     if (cached_stat(file, &mst) == 0) {
    922 	nearmisses++;
    923 	return file;
    924     }
    925     free(file);
    926     return NULL;
    927 }
    928 
    929 /*-
    930  *-----------------------------------------------------------------------
    931  * DirLookupAbs  --
    932  *	Find if the file with the given name exists in the given path.
    933  *
    934  * Results:
    935  *	The path to the file, the empty string or NULL. If the file is
    936  *	the empty string, the search should be terminated.
    937  *	This path is guaranteed to be in a different part of memory
    938  *	than name and so may be safely free'd.
    939  *
    940  * Side Effects:
    941  *	None.
    942  *-----------------------------------------------------------------------
    943  */
    944 static char *
    945 DirLookupAbs(CachedDir *dir, const char *name, const char *cp)
    946 {
    947     char *p1;			/* pointer into dir->name */
    948     const char *p2;		/* pointer into name */
    949 
    950     DIR_DEBUG1("   %s ...\n", dir->name);
    951 
    952     /*
    953      * If the file has a leading path component and that component
    954      * exactly matches the entire name of the current search
    955      * directory, we can attempt another cache lookup. And if we don't
    956      * have a hit, we can safely assume the file does not exist at all.
    957      */
    958     for (p1 = dir->name, p2 = name; *p1 && *p1 == *p2; p1++, p2++) {
    959 	continue;
    960     }
    961     if (*p1 != '\0' || p2 != cp - 1) {
    962 	return NULL;
    963     }
    964 
    965     if (Hash_FindEntry(&dir->files, cp) == NULL) {
    966 	DIR_DEBUG0("   must be here but isn't -- returning\n");
    967 	/* Return empty string: terminates search */
    968 	return bmake_strdup("");
    969     }
    970 
    971     dir->hits++;
    972     hits++;
    973     DIR_DEBUG1("   returning %s\n", name);
    974     return bmake_strdup(name);
    975 }
    976 
    977 /* Find the file given on "." or curdir.
    978  * Return the freshly allocated path to the file, or NULL. */
    979 static char *
    980 DirFindDot(const char *name, const char *base)
    981 {
    982 
    983     if (Hash_FindEntry(&dot->files, base) != NULL) {
    984 	DIR_DEBUG0("   in '.'\n");
    985 	hits++;
    986 	dot->hits++;
    987 	return bmake_strdup(name);
    988     }
    989     if (cur != NULL && Hash_FindEntry(&cur->files, base) != NULL) {
    990 	DIR_DEBUG1("   in ${.CURDIR} = %s\n", cur->name);
    991 	hits++;
    992 	cur->hits++;
    993 	return str_concat3(cur->name, "/", base);
    994     }
    995 
    996     return NULL;
    997 }
    998 
    999 /* Find the file with the given name along the given search path.
   1000  *
   1001  * If the file is found in a directory that is not on the path
   1002  * already (either 'name' is absolute or it is a relative path
   1003  * [ dir1/.../dirn/file ] which exists below one of the directories
   1004  * already on the search path), its directory is added to the end
   1005  * of the path, on the assumption that there will be more files in
   1006  * that directory later on. Sometimes this is true. Sometimes not.
   1007  *
   1008  * Input:
   1009  *	name		the file to find
   1010  *	path		the directories to search, or NULL
   1011  *
   1012  * Results:
   1013  *	The freshly allocated path to the file, or NULL.
   1014  */
   1015 char *
   1016 Dir_FindFile(const char *name, SearchPath *path)
   1017 {
   1018     SearchPathNode *ln;
   1019     char *file;			/* the current filename to check */
   1020     const char *base;		/* Terminal name of file */
   1021     Boolean hasLastDot = FALSE;	/* true if we should search dot last */
   1022     Boolean hasSlash;		/* true if 'name' contains a / */
   1023     struct make_stat mst;	/* Buffer for stat, if necessary */
   1024     const char *trailing_dot = ".";
   1025 
   1026     /*
   1027      * Find the final component of the name and note whether it has a
   1028      * slash in it (the name, I mean)
   1029      */
   1030     base = strrchr(name, '/');
   1031     if (base) {
   1032 	hasSlash = TRUE;
   1033 	base++;
   1034     } else {
   1035 	hasSlash = FALSE;
   1036 	base = name;
   1037     }
   1038 
   1039     DIR_DEBUG1("Searching for %s ...", name);
   1040 
   1041     if (path == NULL) {
   1042 	DIR_DEBUG0("couldn't open path, file not found\n");
   1043 	misses++;
   1044 	return NULL;
   1045     }
   1046 
   1047     if ((ln = path->first) != NULL) {
   1048 	CachedDir *dir = ln->datum;
   1049 	if (dir == dotLast) {
   1050 	    hasLastDot = TRUE;
   1051 	    DIR_DEBUG0("[dot last]...");
   1052 	}
   1053     }
   1054     DIR_DEBUG0("\n");
   1055 
   1056     /*
   1057      * If there's no leading directory components or if the leading
   1058      * directory component is exactly `./', consult the cached contents
   1059      * of each of the directories on the search path.
   1060      */
   1061     if (!hasSlash || (base - name == 2 && *name == '.')) {
   1062 	/*
   1063 	 * We look through all the directories on the path seeking one which
   1064 	 * contains the final component of the given name.  If such a beast
   1065 	 * is found, we concatenate the directory name and the final
   1066 	 * component and return the resulting string. If we don't find any
   1067 	 * such thing, we go on to phase two...
   1068 	 *
   1069 	 * No matter what, we always look for the file in the current
   1070 	 * directory before anywhere else (unless we found the magic
   1071 	 * DOTLAST path, in which case we search it last) and we *do not*
   1072 	 * add the ./ to it if it exists.
   1073 	 * This is so there are no conflicts between what the user
   1074 	 * specifies (fish.c) and what pmake finds (./fish.c).
   1075 	 */
   1076 	if (!hasLastDot && (file = DirFindDot(name, base)) != NULL)
   1077 	    return file;
   1078 
   1079 	for (; ln != NULL; ln = ln->next) {
   1080 	    CachedDir *dir = ln->datum;
   1081 	    if (dir == dotLast)
   1082 		continue;
   1083 	    if ((file = DirLookup(dir, base)) != NULL)
   1084 		return file;
   1085 	}
   1086 
   1087 	if (hasLastDot && (file = DirFindDot(name, base)) != NULL)
   1088 	    return file;
   1089     }
   1090 
   1091     /*
   1092      * We didn't find the file on any directory in the search path.
   1093      * If the name doesn't contain a slash, that means it doesn't exist.
   1094      * If it *does* contain a slash, however, there is still hope: it
   1095      * could be in a subdirectory of one of the members of the search
   1096      * path. (eg. /usr/include and sys/types.h. The above search would
   1097      * fail to turn up types.h in /usr/include, but it *is* in
   1098      * /usr/include/sys/types.h).
   1099      * [ This no longer applies: If we find such a beast, we assume there
   1100      * will be more (what else can we assume?) and add all but the last
   1101      * component of the resulting name onto the search path (at the
   1102      * end).]
   1103      * This phase is only performed if the file is *not* absolute.
   1104      */
   1105     if (!hasSlash) {
   1106 	DIR_DEBUG0("   failed.\n");
   1107 	misses++;
   1108 	return NULL;
   1109     }
   1110 
   1111     if (*base == '\0') {
   1112 	/* we were given a trailing "/" */
   1113 	base = trailing_dot;
   1114     }
   1115 
   1116     if (name[0] != '/') {
   1117 	Boolean checkedDot = FALSE;
   1118 
   1119 	DIR_DEBUG0("   Trying subdirectories...\n");
   1120 
   1121 	if (!hasLastDot) {
   1122 	    if (dot) {
   1123 		checkedDot = TRUE;
   1124 		if ((file = DirLookupSubdir(dot, name)) != NULL)
   1125 		    return file;
   1126 	    }
   1127 	    if (cur && (file = DirLookupSubdir(cur, name)) != NULL)
   1128 		return file;
   1129 	}
   1130 
   1131 	for (ln = path->first; ln != NULL; ln = ln->next) {
   1132 	    CachedDir *dir = ln->datum;
   1133 	    if (dir == dotLast)
   1134 		continue;
   1135 	    if (dir == dot) {
   1136 		if (checkedDot)
   1137 		    continue;
   1138 		checkedDot = TRUE;
   1139 	    }
   1140 	    if ((file = DirLookupSubdir(dir, name)) != NULL)
   1141 		return file;
   1142 	}
   1143 
   1144 	if (hasLastDot) {
   1145 	    if (dot && !checkedDot) {
   1146 		checkedDot = TRUE;
   1147 		if ((file = DirLookupSubdir(dot, name)) != NULL)
   1148 		    return file;
   1149 	    }
   1150 	    if (cur && (file = DirLookupSubdir(cur, name)) != NULL)
   1151 		return file;
   1152 	}
   1153 
   1154 	if (checkedDot) {
   1155 	    /*
   1156 	     * Already checked by the given name, since . was in the path,
   1157 	     * so no point in proceeding...
   1158 	     */
   1159 	    DIR_DEBUG0("   Checked . already, returning NULL\n");
   1160 	    return NULL;
   1161 	}
   1162 
   1163     } else { /* name[0] == '/' */
   1164 
   1165 	/*
   1166 	 * For absolute names, compare directory path prefix against the
   1167 	 * the directory path of each member on the search path for an exact
   1168 	 * match. If we have an exact match on any member of the search path,
   1169 	 * use the cached contents of that member to lookup the final file
   1170 	 * component. If that lookup fails we can safely assume that the
   1171 	 * file does not exist at all.  This is signified by DirLookupAbs()
   1172 	 * returning an empty string.
   1173 	 */
   1174 	DIR_DEBUG0("   Trying exact path matches...\n");
   1175 
   1176 	if (!hasLastDot && cur &&
   1177 	    ((file = DirLookupAbs(cur, name, base)) != NULL)) {
   1178 	    if (file[0] == '\0') {
   1179 		free(file);
   1180 		return NULL;
   1181 	    }
   1182 	    return file;
   1183 	}
   1184 
   1185 	for (ln = path->first; ln != NULL; ln = ln->next) {
   1186 	    CachedDir *dir = ln->datum;
   1187 	    if (dir == dotLast)
   1188 		continue;
   1189 	    if ((file = DirLookupAbs(dir, name, base)) != NULL) {
   1190 		if (file[0] == '\0') {
   1191 		    free(file);
   1192 		    return NULL;
   1193 		}
   1194 		return file;
   1195 	    }
   1196 	}
   1197 
   1198 	if (hasLastDot && cur &&
   1199 	    ((file = DirLookupAbs(cur, name, base)) != NULL)) {
   1200 	    if (file[0] == '\0') {
   1201 		free(file);
   1202 		return NULL;
   1203 	    }
   1204 	    return file;
   1205 	}
   1206     }
   1207 
   1208     /*
   1209      * Didn't find it that way, either. Sigh. Phase 3. Add its directory
   1210      * onto the search path in any case, just in case, then look for the
   1211      * thing in the hash table. If we find it, grand. We return a new
   1212      * copy of the name. Otherwise we sadly return a NULL pointer. Sigh.
   1213      * Note that if the directory holding the file doesn't exist, this will
   1214      * do an extra search of the final directory on the path. Unless something
   1215      * weird happens, this search won't succeed and life will be groovy.
   1216      *
   1217      * Sigh. We cannot add the directory onto the search path because
   1218      * of this amusing case:
   1219      * $(INSTALLDIR)/$(FILE): $(FILE)
   1220      *
   1221      * $(FILE) exists in $(INSTALLDIR) but not in the current one.
   1222      * When searching for $(FILE), we will find it in $(INSTALLDIR)
   1223      * b/c we added it here. This is not good...
   1224      */
   1225 #ifdef notdef
   1226     if (base == trailing_dot) {
   1227 	base = strrchr(name, '/');
   1228 	base++;
   1229     }
   1230     base[-1] = '\0';
   1231     (void)Dir_AddDir(path, name);
   1232     base[-1] = '/';
   1233 
   1234     bigmisses++;
   1235     ln = Lst_Last(path);
   1236     if (ln == NULL) {
   1237 	return NULL;
   1238     } else {
   1239 	dir = LstNode_Datum(ln);
   1240     }
   1241 
   1242     if (Hash_FindEntry(&dir->files, base) != NULL) {
   1243 	return bmake_strdup(name);
   1244     } else {
   1245 	return NULL;
   1246     }
   1247 #else /* !notdef */
   1248     DIR_DEBUG1("   Looking for \"%s\" ...\n", name);
   1249 
   1250     bigmisses++;
   1251     if (cached_stat(name, &mst) == 0) {
   1252 	return bmake_strdup(name);
   1253     }
   1254 
   1255     DIR_DEBUG0("   failed. Returning NULL\n");
   1256     return NULL;
   1257 #endif /* notdef */
   1258 }
   1259 
   1260 
   1261 /* Search for a path starting at a given directory and then working our way
   1262  * up towards the root.
   1263  *
   1264  * Input:
   1265  *	here		starting directory
   1266  *	search_path	the relative path we are looking for
   1267  *
   1268  * Results:
   1269  *	The found path, or NULL.
   1270  */
   1271 char *
   1272 Dir_FindHereOrAbove(const char *here, const char *search_path)
   1273 {
   1274     struct make_stat mst;
   1275     char *dirbase, *dirbase_end;
   1276     char *try, *try_end;
   1277 
   1278     /* copy out our starting point */
   1279     dirbase = bmake_strdup(here);
   1280     dirbase_end = dirbase + strlen(dirbase);
   1281 
   1282     /* loop until we determine a result */
   1283     for (;;) {
   1284 
   1285 	/* try and stat(2) it ... */
   1286 	try = str_concat3(dirbase, "/", search_path);
   1287 	if (cached_stat(try, &mst) != -1) {
   1288 	    /*
   1289 	     * success!  if we found a file, chop off
   1290 	     * the filename so we return a directory.
   1291 	     */
   1292 	    if ((mst.mst_mode & S_IFMT) != S_IFDIR) {
   1293 		try_end = try + strlen(try);
   1294 		while (try_end > try && *try_end != '/')
   1295 		    try_end--;
   1296 		if (try_end > try)
   1297 		    *try_end = '\0';	/* chop! */
   1298 	    }
   1299 
   1300 	    free(dirbase);
   1301 	    return try;
   1302 	}
   1303 	free(try);
   1304 
   1305 	/*
   1306 	 * nope, we didn't find it.  if we used up dirbase we've
   1307 	 * reached the root and failed.
   1308 	 */
   1309 	if (dirbase_end == dirbase)
   1310 	    break;		/* failed! */
   1311 
   1312 	/*
   1313 	 * truncate dirbase from the end to move up a dir
   1314 	 */
   1315 	while (dirbase_end > dirbase && *dirbase_end != '/')
   1316 	    dirbase_end--;
   1317 	*dirbase_end = '\0';	/* chop! */
   1318     }
   1319 
   1320     free(dirbase);
   1321     return NULL;
   1322 }
   1323 
   1324 /*-
   1325  *-----------------------------------------------------------------------
   1326  * Dir_MTime  --
   1327  *	Find the modification time of the file described by gn along the
   1328  *	search path dirSearchPath.
   1329  *
   1330  * Input:
   1331  *	gn		the file whose modification time is desired
   1332  *
   1333  * Results:
   1334  *	The modification time or 0 if it doesn't exist
   1335  *
   1336  * Side Effects:
   1337  *	The modification time is placed in the node's mtime slot.
   1338  *	If the node didn't have a path entry before, and Dir_FindFile
   1339  *	found one for it, the full name is placed in the path slot.
   1340  *-----------------------------------------------------------------------
   1341  */
   1342 time_t
   1343 Dir_MTime(GNode *gn, Boolean recheck)
   1344 {
   1345     char *fullName;		/* the full pathname of name */
   1346     struct make_stat mst;	/* buffer for finding the mod time */
   1347 
   1348     if (gn->type & OP_ARCHV) {
   1349 	return Arch_MTime(gn);
   1350     } else if (gn->type & OP_PHONY) {
   1351 	gn->mtime = 0;
   1352 	return 0;
   1353     } else if (gn->path == NULL) {
   1354 	if (gn->type & OP_NOPATH)
   1355 	    fullName = NULL;
   1356 	else {
   1357 	    fullName = Dir_FindFile(gn->name, Suff_FindPath(gn));
   1358 	    if (fullName == NULL && gn->flags & FROM_DEPEND &&
   1359 		!Lst_IsEmpty(gn->implicitParents)) {
   1360 		char *cp;
   1361 
   1362 		cp = strrchr(gn->name, '/');
   1363 		if (cp) {
   1364 		    /*
   1365 		     * This is an implied source, and it may have moved,
   1366 		     * see if we can find it via the current .PATH
   1367 		     */
   1368 		    cp++;
   1369 
   1370 		    fullName = Dir_FindFile(cp, Suff_FindPath(gn));
   1371 		    if (fullName) {
   1372 			/*
   1373 			 * Put the found file in gn->path
   1374 			 * so that we give that to the compiler.
   1375 			 */
   1376 			gn->path = bmake_strdup(fullName);
   1377 			if (!Job_RunTarget(".STALE", gn->fname))
   1378 			    fprintf(stdout,
   1379 				    "%s: %s, %d: ignoring stale %s for %s, "
   1380 				    "found %s\n", progname, gn->fname,
   1381 				    gn->lineno,
   1382 				    makeDependfile, gn->name, fullName);
   1383 		    }
   1384 		}
   1385 	    }
   1386 	    DIR_DEBUG2("Found '%s' as '%s'\n",
   1387 		       gn->name, fullName ? fullName : "(not found)");
   1388 	}
   1389     } else {
   1390 	fullName = gn->path;
   1391     }
   1392 
   1393     if (fullName == NULL) {
   1394 	fullName = bmake_strdup(gn->name);
   1395     }
   1396 
   1397     if (cached_stats(&mtimes, fullName, &mst, recheck ? CST_UPDATE : 0) < 0) {
   1398 	if (gn->type & OP_MEMBER) {
   1399 	    if (fullName != gn->path)
   1400 		free(fullName);
   1401 	    return Arch_MemMTime(gn);
   1402 	} else {
   1403 	    mst.mst_mtime = 0;
   1404 	}
   1405     }
   1406 
   1407     if (fullName && gn->path == NULL) {
   1408 	gn->path = fullName;
   1409     }
   1410 
   1411     gn->mtime = mst.mst_mtime;
   1412     return gn->mtime;
   1413 }
   1414 
   1415 /* Read the list of filenames in the directory and store the result
   1416  * in openDirectories.
   1417  *
   1418  * If a path is given, append the directory to that path.
   1419  *
   1420  * Input:
   1421  *	path		The path to which the directory should be
   1422  *			added, or NULL to only add the directory to
   1423  *			openDirectories
   1424  *	name		The name of the directory to add.
   1425  *			The name is not normalized in any way.
   1426  */
   1427 CachedDir *
   1428 Dir_AddDir(SearchPath *path, const char *name)
   1429 {
   1430     CachedDir *dir = NULL;	/* the added directory */
   1431     DIR *d;
   1432     struct dirent *dp;
   1433 
   1434     if (path != NULL && strcmp(name, ".DOTLAST") == 0) {
   1435 	SearchPathNode *ln;
   1436 
   1437 	for (ln = path->first; ln != NULL; ln = ln->next) {
   1438 	    CachedDir *pathDir = ln->datum;
   1439 	    if (strcmp(pathDir->name, name) == 0)
   1440 		return pathDir;
   1441 	}
   1442 
   1443 	dotLast->refCount++;
   1444 	Lst_Prepend(path, dotLast);
   1445     }
   1446 
   1447     if (path != NULL)
   1448 	dir = OpenDirs_Find(&openDirs, name);
   1449     if (dir != NULL) {
   1450 	if (Lst_FindDatum(path, dir) == NULL) {
   1451 	    dir->refCount++;
   1452 	    Lst_Append(path, dir);
   1453 	}
   1454 	return dir;
   1455     }
   1456 
   1457     DIR_DEBUG1("Caching %s ...", name);
   1458 
   1459     if ((d = opendir(name)) != NULL) {
   1460 	dir = bmake_malloc(sizeof(CachedDir));
   1461 	dir->name = bmake_strdup(name);
   1462 	dir->hits = 0;
   1463 	dir->refCount = 1;
   1464 	Hash_InitTable(&dir->files);
   1465 
   1466 	while ((dp = readdir(d)) != NULL) {
   1467 #if defined(sun) && defined(d_ino) /* d_ino is a sunos4 #define for d_fileno */
   1468 	    /*
   1469 	     * The sun directory library doesn't check for a 0 inode
   1470 	     * (0-inode slots just take up space), so we have to do
   1471 	     * it ourselves.
   1472 	     */
   1473 	    if (dp->d_fileno == 0) {
   1474 		continue;
   1475 	    }
   1476 #endif /* sun && d_ino */
   1477 	    (void)Hash_CreateEntry(&dir->files, dp->d_name, NULL);
   1478 	}
   1479 	(void)closedir(d);
   1480 	OpenDirs_Add(&openDirs, dir);
   1481 	if (path != NULL)
   1482 	    Lst_Append(path, dir);
   1483     }
   1484     DIR_DEBUG0("done\n");
   1485     return dir;
   1486 }
   1487 
   1488 /*-
   1489  *-----------------------------------------------------------------------
   1490  * Dir_CopyDir --
   1491  *	Callback function for duplicating a search path via Lst_Copy.
   1492  *	Ups the reference count for the directory.
   1493  *
   1494  * Results:
   1495  *	Returns the Path it was given.
   1496  *-----------------------------------------------------------------------
   1497  */
   1498 void *
   1499 Dir_CopyDir(void *p)
   1500 {
   1501     CachedDir *dir = p;
   1502     dir->refCount++;
   1503     return dir;
   1504 }
   1505 
   1506 /*-
   1507  *-----------------------------------------------------------------------
   1508  * Dir_MakeFlags --
   1509  *	Make a string by taking all the directories in the given search
   1510  *	path and preceding them by the given flag. Used by the suffix
   1511  *	module to create variables for compilers based on suffix search
   1512  *	paths.
   1513  *
   1514  * Input:
   1515  *	flag		flag which should precede each directory
   1516  *	path		list of directories
   1517  *
   1518  * Results:
   1519  *	The string mentioned above. Note that there is no space between
   1520  *	the given flag and each directory. The empty string is returned if
   1521  *	Things don't go well.
   1522  *
   1523  * Side Effects:
   1524  *	None
   1525  *-----------------------------------------------------------------------
   1526  */
   1527 char *
   1528 Dir_MakeFlags(const char *flag, SearchPath *path)
   1529 {
   1530     Buffer buf;
   1531     SearchPathNode *ln;
   1532 
   1533     Buf_Init(&buf, 0);
   1534 
   1535     if (path != NULL) {
   1536 	for (ln = path->first; ln != NULL; ln = ln->next) {
   1537 	    CachedDir *dir = ln->datum;
   1538 	    Buf_AddStr(&buf, " ");
   1539 	    Buf_AddStr(&buf, flag);
   1540 	    Buf_AddStr(&buf, dir->name);
   1541 	}
   1542     }
   1543 
   1544     return Buf_Destroy(&buf, FALSE);
   1545 }
   1546 
   1547 /*-
   1548  *-----------------------------------------------------------------------
   1549  * Dir_Destroy --
   1550  *	Nuke a directory descriptor, if possible. Callback procedure
   1551  *	for the suffixes module when destroying a search path.
   1552  *
   1553  * Input:
   1554  *	dirp		The directory descriptor to nuke
   1555  *
   1556  * Results:
   1557  *	None.
   1558  *
   1559  * Side Effects:
   1560  *	If no other path references this directory (refCount == 0),
   1561  *	the CachedDir and all its data are freed.
   1562  *
   1563  *-----------------------------------------------------------------------
   1564  */
   1565 void
   1566 Dir_Destroy(void *dirp)
   1567 {
   1568     CachedDir *dir = dirp;
   1569     dir->refCount--;
   1570 
   1571     if (dir->refCount == 0) {
   1572 	OpenDirs_Remove(&openDirs, dir->name);
   1573 
   1574 	Hash_DeleteTable(&dir->files);
   1575 	free(dir->name);
   1576 	free(dir);
   1577     }
   1578 }
   1579 
   1580 /*-
   1581  *-----------------------------------------------------------------------
   1582  * Dir_ClearPath --
   1583  *	Clear out all elements of the given search path. This is different
   1584  *	from destroying the list, notice.
   1585  *
   1586  * Input:
   1587  *	path		Path to clear
   1588  *
   1589  * Results:
   1590  *	None.
   1591  *
   1592  * Side Effects:
   1593  *	The path is set to the empty list.
   1594  *
   1595  *-----------------------------------------------------------------------
   1596  */
   1597 void
   1598 Dir_ClearPath(SearchPath *path)
   1599 {
   1600     while (!Lst_IsEmpty(path)) {
   1601 	CachedDir *dir = Lst_Dequeue(path);
   1602 	Dir_Destroy(dir);
   1603     }
   1604 }
   1605 
   1606 
   1607 /*-
   1608  *-----------------------------------------------------------------------
   1609  * Dir_Concat --
   1610  *	Concatenate two paths, adding the second to the end of the first.
   1611  *	Makes sure to avoid duplicates.
   1612  *
   1613  * Input:
   1614  *	path1		Dest
   1615  *	path2		Source
   1616  *
   1617  * Results:
   1618  *	None
   1619  *
   1620  * Side Effects:
   1621  *	Reference counts for added dirs are upped.
   1622  *
   1623  *-----------------------------------------------------------------------
   1624  */
   1625 void
   1626 Dir_Concat(SearchPath *path1, SearchPath *path2)
   1627 {
   1628     SearchPathNode *ln;
   1629 
   1630     for (ln = path2->first; ln != NULL; ln = ln->next) {
   1631 	CachedDir *dir = ln->datum;
   1632 	if (Lst_FindDatum(path1, dir) == NULL) {
   1633 	    dir->refCount++;
   1634 	    Lst_Append(path1, dir);
   1635 	}
   1636     }
   1637 }
   1638 
   1639 static int
   1640 percentage(int num, int den)
   1641 {
   1642     return den != 0 ? num * 100 / den : 0;
   1643 }
   1644 
   1645 /********** DEBUG INFO **********/
   1646 void
   1647 Dir_PrintDirectories(void)
   1648 {
   1649     CachedDirListNode *ln;
   1650 
   1651     debug_printf("#*** Directory Cache:\n");
   1652     debug_printf("# Stats: %d hits %d misses %d near misses %d losers (%d%%)\n",
   1653 		 hits, misses, nearmisses, bigmisses,
   1654 		 percentage(hits, hits + bigmisses + nearmisses));
   1655     debug_printf("# %-20s referenced\thits\n", "directory");
   1656 
   1657     for (ln = openDirs.list->first; ln != NULL; ln = ln->next) {
   1658 	CachedDir *dir = ln->datum;
   1659 	debug_printf("# %-20s %10d\t%4d\n", dir->name, dir->refCount,
   1660 		     dir->hits);
   1661     }
   1662 }
   1663 
   1664 void
   1665 Dir_PrintPath(SearchPath *path)
   1666 {
   1667     SearchPathNode *node;
   1668     for (node = path->first; node != NULL; node = node->next) {
   1669 	const CachedDir *dir = node->datum;
   1670 	debug_printf("%s ", dir->name);
   1671     }
   1672 }
   1673