xref: /freebsd/contrib/bmake/meta.c (revision cd8537910406e68d4719136a5b0cf6d23bb1b23b)
1 /*      $NetBSD: meta.c,v 1.144 2020/11/15 12:02:44 rillig Exp $ */
2 
3 /*
4  * Implement 'meta' mode.
5  * Adapted from John Birrell's patches to FreeBSD make.
6  * --sjg
7  */
8 /*
9  * Copyright (c) 2009-2016, Juniper Networks, Inc.
10  * Portions Copyright (c) 2009, John Birrell.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 #if defined(USE_META)
34 
35 #ifdef HAVE_CONFIG_H
36 # include "config.h"
37 #endif
38 #include <sys/stat.h>
39 #ifdef HAVE_LIBGEN_H
40 #include <libgen.h>
41 #elif !defined(HAVE_DIRNAME)
42 char * dirname(char *);
43 #endif
44 #include <errno.h>
45 #if !defined(HAVE_CONFIG_H) || defined(HAVE_ERR_H)
46 #include <err.h>
47 #endif
48 
49 #include "make.h"
50 #include "dir.h"
51 #include "job.h"
52 
53 #ifdef USE_FILEMON
54 #include "filemon/filemon.h"
55 #endif
56 
57 static BuildMon Mybm;			/* for compat */
58 static StringList *metaBailiwick;	/* our scope of control */
59 static char *metaBailiwickStr;		/* string storage for the list */
60 static StringList *metaIgnorePaths;	/* paths we deliberately ignore */
61 static char *metaIgnorePathsStr;	/* string storage for the list */
62 
63 #ifndef MAKE_META_IGNORE_PATHS
64 #define MAKE_META_IGNORE_PATHS ".MAKE.META.IGNORE_PATHS"
65 #endif
66 #ifndef MAKE_META_IGNORE_PATTERNS
67 #define MAKE_META_IGNORE_PATTERNS ".MAKE.META.IGNORE_PATTERNS"
68 #endif
69 #ifndef MAKE_META_IGNORE_FILTER
70 #define MAKE_META_IGNORE_FILTER ".MAKE.META.IGNORE_FILTER"
71 #endif
72 
73 Boolean useMeta = FALSE;
74 static Boolean useFilemon = FALSE;
75 static Boolean writeMeta = FALSE;
76 static Boolean metaMissing = FALSE;	/* oodate if missing */
77 static Boolean filemonMissing = FALSE;	/* oodate if missing */
78 static Boolean metaEnv = FALSE;		/* don't save env unless asked */
79 static Boolean metaVerbose = FALSE;
80 static Boolean metaIgnoreCMDs = FALSE;	/* ignore CMDs in .meta files */
81 static Boolean metaIgnorePatterns = FALSE; /* do we need to do pattern matches */
82 static Boolean metaIgnoreFilter = FALSE;   /* do we have more complex filtering? */
83 static Boolean metaCurdirOk = FALSE;	/* write .meta in .CURDIR Ok? */
84 static Boolean metaSilent = FALSE;	/* if we have a .meta be SILENT */
85 
86 extern Boolean forceJobs;
87 extern char    **environ;
88 
89 #define	MAKE_META_PREFIX	".MAKE.META.PREFIX"
90 
91 #ifndef N2U
92 # define N2U(n, u)   (((n) + ((u) - 1)) / (u))
93 #endif
94 #ifndef ROUNDUP
95 # define ROUNDUP(n, u)   (N2U((n), (u)) * (u))
96 #endif
97 
98 #if !defined(HAVE_STRSEP)
99 # define strsep(s, d) stresep((s), (d), '\0')
100 #endif
101 
102 /*
103  * Filemon is a kernel module which snoops certain syscalls.
104  *
105  * C chdir
106  * E exec
107  * F [v]fork
108  * L [sym]link
109  * M rename
110  * R read
111  * W write
112  * S stat
113  *
114  * See meta_oodate below - we mainly care about 'E' and 'R'.
115  *
116  * We can still use meta mode without filemon, but
117  * the benefits are more limited.
118  */
119 #ifdef USE_FILEMON
120 
121 /*
122  * Open the filemon device.
123  */
124 static void
125 meta_open_filemon(BuildMon *pbm)
126 {
127     int dupfd;
128 
129     pbm->mon_fd = -1;
130     pbm->filemon = NULL;
131     if (!useFilemon || !pbm->mfp)
132 	return;
133 
134     pbm->filemon = filemon_open();
135     if (pbm->filemon == NULL) {
136 	useFilemon = FALSE;
137 	warn("Could not open filemon %s", filemon_path());
138 	return;
139     }
140 
141     /*
142      * We use a file outside of '.'
143      * to avoid a FreeBSD kernel bug where unlink invalidates
144      * cwd causing getcwd to do a lot more work.
145      * We only care about the descriptor.
146      */
147     pbm->mon_fd = mkTempFile("filemon.XXXXXX", NULL);
148     if ((dupfd = dup(pbm->mon_fd)) == -1) {
149 	err(1, "Could not dup filemon output!");
150     }
151     (void)fcntl(dupfd, F_SETFD, FD_CLOEXEC);
152     if (filemon_setfd(pbm->filemon, dupfd) == -1) {
153 	err(1, "Could not set filemon file descriptor!");
154     }
155     /* we don't need these once we exec */
156     (void)fcntl(pbm->mon_fd, F_SETFD, FD_CLOEXEC);
157 }
158 
159 /*
160  * Read the build monitor output file and write records to the target's
161  * metadata file.
162  */
163 static int
164 filemon_read(FILE *mfp, int fd)
165 {
166     char buf[BUFSIZ];
167     int error;
168 
169     /* Check if we're not writing to a meta data file.*/
170     if (mfp == NULL) {
171 	if (fd >= 0)
172 	    close(fd);			/* not interested */
173 	return 0;
174     }
175     /* rewind */
176     if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
177 	error = errno;
178 	warn("Could not rewind filemon");
179 	fprintf(mfp, "\n");
180     } else {
181 	ssize_t n;
182 
183 	error = 0;
184 	fprintf(mfp, "\n-- filemon acquired metadata --\n");
185 
186 	while ((n = read(fd, buf, sizeof buf)) > 0) {
187 	    if ((ssize_t)fwrite(buf, 1, (size_t)n, mfp) < n)
188 		error = EIO;
189 	}
190     }
191     fflush(mfp);
192     if (close(fd) < 0)
193 	error = errno;
194     return error;
195 }
196 #endif
197 
198 /*
199  * when realpath() fails,
200  * we use this, to clean up ./ and ../
201  */
202 static void
203 eat_dots(char *buf, size_t bufsz, int dots)
204 {
205     char *cp;
206     char *cp2;
207     const char *eat;
208     size_t eatlen;
209 
210     switch (dots) {
211     case 1:
212 	eat = "/./";
213 	eatlen = 2;
214 	break;
215     case 2:
216 	eat = "/../";
217 	eatlen = 3;
218 	break;
219     default:
220 	return;
221     }
222 
223     do {
224 	cp = strstr(buf, eat);
225 	if (cp) {
226 	    cp2 = cp + eatlen;
227 	    if (dots == 2 && cp > buf) {
228 		do {
229 		    cp--;
230 		} while (cp > buf && *cp != '/');
231 	    }
232 	    if (*cp == '/') {
233 		strlcpy(cp, cp2, bufsz - (size_t)(cp - buf));
234 	    } else {
235 		return;			/* can't happen? */
236 	    }
237 	}
238     } while (cp);
239 }
240 
241 static char *
242 meta_name(char *mname, size_t mnamelen,
243 	  const char *dname,
244 	  const char *tname,
245 	  const char *cwd)
246 {
247     char buf[MAXPATHLEN];
248     char *rp;
249     char *cp;
250     char *tp;
251     char *dtp;
252     size_t ldname;
253 
254     /*
255      * Weed out relative paths from the target file name.
256      * We have to be careful though since if target is a
257      * symlink, the result will be unstable.
258      * So we use realpath() just to get the dirname, and leave the
259      * basename as given to us.
260      */
261     if ((cp = strrchr(tname, '/'))) {
262 	if (cached_realpath(tname, buf)) {
263 	    if ((rp = strrchr(buf, '/'))) {
264 		rp++;
265 		cp++;
266 		if (strcmp(cp, rp) != 0)
267 		    strlcpy(rp, cp, sizeof buf - (size_t)(rp - buf));
268 	    }
269 	    tname = buf;
270 	} else {
271 	    /*
272 	     * We likely have a directory which is about to be made.
273 	     * We pretend realpath() succeeded, to have a chance
274 	     * of generating the same meta file name that we will
275 	     * next time through.
276 	     */
277 	    if (tname[0] == '/') {
278 		strlcpy(buf, tname, sizeof buf);
279 	    } else {
280 		snprintf(buf, sizeof buf, "%s/%s", cwd, tname);
281 	    }
282 	    eat_dots(buf, sizeof buf, 1);	/* ./ */
283 	    eat_dots(buf, sizeof buf, 2);	/* ../ */
284 	    tname = buf;
285 	}
286     }
287     /* on some systems dirname may modify its arg */
288     tp = bmake_strdup(tname);
289     dtp = dirname(tp);
290     if (strcmp(dname, dtp) == 0)
291 	snprintf(mname, mnamelen, "%s.meta", tname);
292     else {
293 	ldname = strlen(dname);
294 	if (strncmp(dname, dtp, ldname) == 0 && dtp[ldname] == '/')
295 	    snprintf(mname, mnamelen, "%s/%s.meta", dname, &tname[ldname+1]);
296 	else
297 	    snprintf(mname, mnamelen, "%s/%s.meta", dname, tname);
298 
299 	/*
300 	 * Replace path separators in the file name after the
301 	 * current object directory path.
302 	 */
303 	cp = mname + strlen(dname) + 1;
304 
305 	while (*cp != '\0') {
306 	    if (*cp == '/')
307 		*cp = '_';
308 	    cp++;
309 	}
310     }
311     free(tp);
312     return mname;
313 }
314 
315 /*
316  * Return true if running ${.MAKE}
317  * Bypassed if target is flagged .MAKE
318  */
319 static int
320 is_submake(void *cmdp, void *gnp)
321 {
322     static const char *p_make = NULL;
323     static size_t p_len;
324     char  *cmd = cmdp;
325     GNode *gn = gnp;
326     char *mp = NULL;
327     char *cp;
328     char *cp2;
329     int rc = 0;				/* keep looking */
330 
331     if (p_make == NULL) {
332 	void *dontFreeIt;
333 	p_make = Var_Value(".MAKE", gn, &dontFreeIt);
334 	p_len = strlen(p_make);
335     }
336     cp = strchr(cmd, '$');
337     if ((cp)) {
338 	(void)Var_Subst(cmd, gn, VARE_WANTRES, &mp);
339 	/* TODO: handle errors */
340 	cmd = mp;
341     }
342     cp2 = strstr(cmd, p_make);
343     if (cp2 != NULL) {
344 	switch (cp2[p_len]) {
345 	case '\0':
346 	case ' ':
347 	case '\t':
348 	case '\n':
349 	    rc = 1;
350 	    break;
351 	}
352 	if (cp2 > cmd && rc > 0) {
353 	    switch (cp2[-1]) {
354 	    case ' ':
355 	    case '\t':
356 	    case '\n':
357 		break;
358 	    default:
359 		rc = 0;			/* no match */
360 		break;
361 	    }
362 	}
363     }
364     free(mp);
365     return rc;
366 }
367 
368 typedef struct meta_file_s {
369     FILE *fp;
370     GNode *gn;
371 } meta_file_t;
372 
373 static void
374 printCMD(const char *cmd, meta_file_t *mfp)
375 {
376     char *cmd_freeIt = NULL;
377 
378     if (strchr(cmd, '$')) {
379 	(void)Var_Subst(cmd, mfp->gn, VARE_WANTRES, &cmd_freeIt);
380 	/* TODO: handle errors */
381 	cmd = cmd_freeIt;
382     }
383     fprintf(mfp->fp, "CMD %s\n", cmd);
384     free(cmd_freeIt);
385 }
386 
387 static void
388 printCMDs(GNode *gn, meta_file_t *mf)
389 {
390     GNodeListNode *ln;
391 
392     for (ln = gn->commands->first; ln != NULL; ln = ln->next)
393 	printCMD(ln->datum, mf);
394 }
395 
396 /*
397  * Certain node types never get a .meta file
398  */
399 #define SKIP_META_TYPE(_type) do { \
400     if ((gn->type & __CONCAT(OP_, _type))) { \
401 	if (verbose) { \
402 	    debug_printf("Skipping meta for %s: .%s\n", \
403 		    gn->name, __STRING(_type)); \
404 	} \
405 	return FALSE; \
406     } \
407 } while (0)
408 
409 
410 /*
411  * Do we need/want a .meta file ?
412  */
413 static Boolean
414 meta_needed(GNode *gn, const char *dname,
415 	     char *objdir, int verbose)
416 {
417     struct cached_stat cst;
418 
419     if (verbose)
420 	verbose = DEBUG(META);
421 
422     /* This may be a phony node which we don't want meta data for... */
423     /* Skip .meta for .BEGIN, .END, .ERROR etc as well. */
424     /* Or it may be explicitly flagged as .NOMETA */
425     SKIP_META_TYPE(NOMETA);
426     /* Unless it is explicitly flagged as .META */
427     if (!(gn->type & OP_META)) {
428 	SKIP_META_TYPE(PHONY);
429 	SKIP_META_TYPE(SPECIAL);
430 	SKIP_META_TYPE(MAKE);
431     }
432 
433     /* Check if there are no commands to execute. */
434     if (Lst_IsEmpty(gn->commands)) {
435 	if (verbose)
436 	    debug_printf("Skipping meta for %s: no commands\n", gn->name);
437 	return FALSE;
438     }
439     if ((gn->type & (OP_META|OP_SUBMAKE)) == OP_SUBMAKE) {
440 	/* OP_SUBMAKE is a bit too aggressive */
441 	if (Lst_ForEachUntil(gn->commands, is_submake, gn)) {
442 	    DEBUG1(META, "Skipping meta for %s: .SUBMAKE\n", gn->name);
443 	    return FALSE;
444 	}
445     }
446 
447     /* The object directory may not exist. Check it.. */
448     if (cached_stat(dname, &cst) != 0) {
449 	if (verbose)
450 	    debug_printf("Skipping meta for %s: no .OBJDIR\n", gn->name);
451 	return FALSE;
452     }
453 
454     /* make sure these are canonical */
455     if (cached_realpath(dname, objdir))
456 	dname = objdir;
457 
458     /* If we aren't in the object directory, don't create a meta file. */
459     if (!metaCurdirOk && strcmp(curdir, dname) == 0) {
460 	if (verbose)
461 	    debug_printf("Skipping meta for %s: .OBJDIR == .CURDIR\n",
462 			 gn->name);
463 	return FALSE;
464     }
465     return TRUE;
466 }
467 
468 
469 static FILE *
470 meta_create(BuildMon *pbm, GNode *gn)
471 {
472     meta_file_t mf;
473     char buf[MAXPATHLEN];
474     char objdir[MAXPATHLEN];
475     char **ptr;
476     const char *dname;
477     const char *tname;
478     char *fname;
479     const char *cp;
480     void *objdir_freeIt;
481 
482     mf.fp = NULL;
483 
484     dname = Var_Value(".OBJDIR", gn, &objdir_freeIt);
485     tname = GNode_VarTarget(gn);
486 
487     /* if this succeeds objdir is realpath of dname */
488     if (!meta_needed(gn, dname, objdir, TRUE))
489 	goto out;
490     dname = objdir;
491 
492     if (metaVerbose) {
493 	char *mp;
494 
495 	/* Describe the target we are building */
496 	(void)Var_Subst("${" MAKE_META_PREFIX "}", gn, VARE_WANTRES, &mp);
497 	/* TODO: handle errors */
498 	if (*mp)
499 	    fprintf(stdout, "%s\n", mp);
500 	free(mp);
501     }
502     /* Get the basename of the target */
503     if ((cp = strrchr(tname, '/')) == NULL) {
504 	cp = tname;
505     } else {
506 	cp++;
507     }
508 
509     fflush(stdout);
510 
511     if (!writeMeta)
512 	/* Don't create meta data. */
513 	goto out;
514 
515     fname = meta_name(pbm->meta_fname, sizeof pbm->meta_fname,
516 		      dname, tname, objdir);
517 
518 #ifdef DEBUG_META_MODE
519     DEBUG1(META, "meta_create: %s\n", fname);
520 #endif
521 
522     if ((mf.fp = fopen(fname, "w")) == NULL)
523 	err(1, "Could not open meta file '%s'", fname);
524 
525     fprintf(mf.fp, "# Meta data file %s\n", fname);
526 
527     mf.gn = gn;
528 
529     printCMDs(gn, &mf);
530 
531     fprintf(mf.fp, "CWD %s\n", getcwd(buf, sizeof buf));
532     fprintf(mf.fp, "TARGET %s\n", tname);
533     cp = GNode_VarOodate(gn);
534     if (cp && *cp) {
535 	    fprintf(mf.fp, "OODATE %s\n", cp);
536     }
537     if (metaEnv) {
538 	for (ptr = environ; *ptr != NULL; ptr++)
539 	    fprintf(mf.fp, "ENV %s\n", *ptr);
540     }
541 
542     fprintf(mf.fp, "-- command output --\n");
543     fflush(mf.fp);
544 
545     Var_Append(".MAKE.META.FILES", fname, VAR_GLOBAL);
546     Var_Append(".MAKE.META.CREATED", fname, VAR_GLOBAL);
547 
548     gn->type |= OP_META;		/* in case anyone wants to know */
549     if (metaSilent) {
550 	    gn->type |= OP_SILENT;
551     }
552  out:
553     bmake_free(objdir_freeIt);
554 
555     return mf.fp;
556 }
557 
558 static Boolean
559 boolValue(char *s)
560 {
561     switch(*s) {
562     case '0':
563     case 'N':
564     case 'n':
565     case 'F':
566     case 'f':
567 	return FALSE;
568     }
569     return TRUE;
570 }
571 
572 /*
573  * Initialization we need before reading makefiles.
574  */
575 void
576 meta_init(void)
577 {
578 #ifdef USE_FILEMON
579 	/* this allows makefiles to test if we have filemon support */
580 	Var_Set(".MAKE.PATH_FILEMON", filemon_path(), VAR_GLOBAL);
581 #endif
582 }
583 
584 
585 #define get_mode_bf(bf, token) \
586     if ((cp = strstr(make_mode, token))) \
587 	bf = boolValue(cp + sizeof (token) - 1)
588 
589 /*
590  * Initialization we need after reading makefiles.
591  */
592 void
593 meta_mode_init(const char *make_mode)
594 {
595     static int once = 0;
596     char *cp;
597     void *freeIt;
598 
599     useMeta = TRUE;
600     useFilemon = TRUE;
601     writeMeta = TRUE;
602 
603     if (make_mode) {
604 	if (strstr(make_mode, "env"))
605 	    metaEnv = TRUE;
606 	if (strstr(make_mode, "verb"))
607 	    metaVerbose = TRUE;
608 	if (strstr(make_mode, "read"))
609 	    writeMeta = FALSE;
610 	if (strstr(make_mode, "nofilemon"))
611 	    useFilemon = FALSE;
612 	if (strstr(make_mode, "ignore-cmd"))
613 	    metaIgnoreCMDs = TRUE;
614 	if (useFilemon)
615 	    get_mode_bf(filemonMissing, "missing-filemon=");
616 	get_mode_bf(metaCurdirOk, "curdirok=");
617 	get_mode_bf(metaMissing, "missing-meta=");
618 	get_mode_bf(metaSilent, "silent=");
619     }
620     if (metaVerbose && !Var_Exists(MAKE_META_PREFIX, VAR_GLOBAL)) {
621 	/*
622 	 * The default value for MAKE_META_PREFIX
623 	 * prints the absolute path of the target.
624 	 * This works be cause :H will generate '.' if there is no /
625 	 * and :tA will resolve that to cwd.
626 	 */
627 	Var_Set(MAKE_META_PREFIX, "Building ${.TARGET:H:tA}/${.TARGET:T}", VAR_GLOBAL);
628     }
629     if (once)
630 	return;
631     once = 1;
632     memset(&Mybm, 0, sizeof Mybm);
633     /*
634      * We consider ourselves master of all within ${.MAKE.META.BAILIWICK}
635      */
636     metaBailiwick = Lst_New();
637     (void)Var_Subst("${.MAKE.META.BAILIWICK:O:u:tA}",
638 		    VAR_GLOBAL, VARE_WANTRES, &metaBailiwickStr);
639     /* TODO: handle errors */
640     str2Lst_Append(metaBailiwick, metaBailiwickStr);
641     /*
642      * We ignore any paths that start with ${.MAKE.META.IGNORE_PATHS}
643      */
644     metaIgnorePaths = Lst_New();
645     Var_Append(MAKE_META_IGNORE_PATHS,
646 	       "/dev /etc /proc /tmp /var/run /var/tmp ${TMPDIR}", VAR_GLOBAL);
647     (void)Var_Subst("${" MAKE_META_IGNORE_PATHS ":O:u:tA}",
648 		    VAR_GLOBAL, VARE_WANTRES, &metaIgnorePathsStr);
649     /* TODO: handle errors */
650     str2Lst_Append(metaIgnorePaths, metaIgnorePathsStr);
651 
652     /*
653      * We ignore any paths that match ${.MAKE.META.IGNORE_PATTERNS}
654      */
655     freeIt = NULL;
656     if (Var_Value(MAKE_META_IGNORE_PATTERNS, VAR_GLOBAL, &freeIt)) {
657 	metaIgnorePatterns = TRUE;
658 	bmake_free(freeIt);
659     }
660     freeIt = NULL;
661     if (Var_Value(MAKE_META_IGNORE_FILTER, VAR_GLOBAL, &freeIt)) {
662 	metaIgnoreFilter = TRUE;
663 	bmake_free(freeIt);
664     }
665 }
666 
667 /*
668  * In each case below we allow for job==NULL
669  */
670 void
671 meta_job_start(Job *job, GNode *gn)
672 {
673     BuildMon *pbm;
674 
675     if (job != NULL) {
676 	pbm = &job->bm;
677     } else {
678 	pbm = &Mybm;
679     }
680     pbm->mfp = meta_create(pbm, gn);
681 #ifdef USE_FILEMON_ONCE
682     /* compat mode we open the filemon dev once per command */
683     if (job == NULL)
684 	return;
685 #endif
686 #ifdef USE_FILEMON
687     if (pbm->mfp != NULL && useFilemon) {
688 	meta_open_filemon(pbm);
689     } else {
690 	pbm->mon_fd = -1;
691 	pbm->filemon = NULL;
692     }
693 #endif
694 }
695 
696 /*
697  * The child calls this before doing anything.
698  * It does not disturb our state.
699  */
700 void
701 meta_job_child(Job *job)
702 {
703 #ifdef USE_FILEMON
704     BuildMon *pbm;
705 
706     if (job != NULL) {
707 	pbm = &job->bm;
708     } else {
709 	pbm = &Mybm;
710     }
711     if (pbm->mfp != NULL) {
712 	close(fileno(pbm->mfp));
713 	if (useFilemon && pbm->filemon) {
714 	    pid_t pid;
715 
716 	    pid = getpid();
717 	    if (filemon_setpid_child(pbm->filemon, pid) == -1) {
718 		err(1, "Could not set filemon pid!");
719 	    }
720 	}
721     }
722 #endif
723 }
724 
725 void
726 meta_job_parent(Job *job, pid_t pid)
727 {
728 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
729     BuildMon *pbm;
730 
731     if (job != NULL) {
732 	pbm = &job->bm;
733     } else {
734 	pbm = &Mybm;
735     }
736     if (useFilemon && pbm->filemon) {
737 	filemon_setpid_parent(pbm->filemon, pid);
738     }
739 #endif
740 }
741 
742 int
743 meta_job_fd(Job *job)
744 {
745 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
746     BuildMon *pbm;
747 
748     if (job != NULL) {
749 	pbm = &job->bm;
750     } else {
751 	pbm = &Mybm;
752     }
753     if (useFilemon && pbm->filemon) {
754 	return filemon_readfd(pbm->filemon);
755     }
756 #endif
757     return -1;
758 }
759 
760 int
761 meta_job_event(Job *job)
762 {
763 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
764     BuildMon *pbm;
765 
766     if (job != NULL) {
767 	pbm = &job->bm;
768     } else {
769 	pbm = &Mybm;
770     }
771     if (useFilemon && pbm->filemon) {
772 	return filemon_process(pbm->filemon);
773     }
774 #endif
775     return 0;
776 }
777 
778 void
779 meta_job_error(Job *job, GNode *gn, int flags, int status)
780 {
781     char cwd[MAXPATHLEN];
782     BuildMon *pbm;
783 
784     if (job != NULL) {
785 	pbm = &job->bm;
786 	if (gn == NULL)
787 	    gn = job->node;
788     } else {
789 	pbm = &Mybm;
790     }
791     if (pbm->mfp != NULL) {
792 	fprintf(pbm->mfp, "\n*** Error code %d%s\n",
793 		status,
794 		(flags & JOB_IGNERR) ?
795 		"(ignored)" : "");
796     }
797     if (gn) {
798 	Var_Set(".ERROR_TARGET", GNode_Path(gn), VAR_GLOBAL);
799     }
800     getcwd(cwd, sizeof cwd);
801     Var_Set(".ERROR_CWD", cwd, VAR_GLOBAL);
802     if (pbm->meta_fname[0] != '\0') {
803 	Var_Set(".ERROR_META_FILE", pbm->meta_fname, VAR_GLOBAL);
804     }
805     meta_job_finish(job);
806 }
807 
808 void
809 meta_job_output(Job *job, char *cp, const char *nl)
810 {
811     BuildMon *pbm;
812 
813     if (job != NULL) {
814 	pbm = &job->bm;
815     } else {
816 	pbm = &Mybm;
817     }
818     if (pbm->mfp != NULL) {
819 	if (metaVerbose) {
820 	    static char *meta_prefix = NULL;
821 	    static size_t meta_prefix_len;
822 
823 	    if (meta_prefix == NULL) {
824 		char *cp2;
825 
826 		(void)Var_Subst("${" MAKE_META_PREFIX "}",
827 				VAR_GLOBAL, VARE_WANTRES, &meta_prefix);
828 		/* TODO: handle errors */
829 		if ((cp2 = strchr(meta_prefix, '$')))
830 		    meta_prefix_len = (size_t)(cp2 - meta_prefix);
831 		else
832 		    meta_prefix_len = strlen(meta_prefix);
833 	    }
834 	    if (strncmp(cp, meta_prefix, meta_prefix_len) == 0) {
835 		cp = strchr(cp+1, '\n');
836 		if (!cp++)
837 		    return;
838 	    }
839 	}
840 	fprintf(pbm->mfp, "%s%s", cp, nl);
841     }
842 }
843 
844 int
845 meta_cmd_finish(void *pbmp)
846 {
847     int error = 0;
848     BuildMon *pbm = pbmp;
849 #ifdef USE_FILEMON
850     int x;
851 #endif
852 
853     if (pbm == NULL)
854 	pbm = &Mybm;
855 
856 #ifdef USE_FILEMON
857     if (pbm->filemon) {
858 	while (filemon_process(pbm->filemon) > 0)
859 	    continue;
860 	if (filemon_close(pbm->filemon) == -1)
861 	    error = errno;
862 	x = filemon_read(pbm->mfp, pbm->mon_fd);
863 	if (error == 0 && x != 0)
864 	    error = x;
865 	pbm->mon_fd = -1;
866 	pbm->filemon = NULL;
867 	return error;
868     }
869 #endif
870 
871     fprintf(pbm->mfp, "\n");	/* ensure end with newline */
872     return error;
873 }
874 
875 int
876 meta_job_finish(Job *job)
877 {
878     BuildMon *pbm;
879     int error = 0;
880     int x;
881 
882     if (job != NULL) {
883 	pbm = &job->bm;
884     } else {
885 	pbm = &Mybm;
886     }
887     if (pbm->mfp != NULL) {
888 	error = meta_cmd_finish(pbm);
889 	x = fclose(pbm->mfp);
890 	if (error == 0 && x != 0)
891 	    error = errno;
892 	pbm->mfp = NULL;
893 	pbm->meta_fname[0] = '\0';
894     }
895     return error;
896 }
897 
898 void
899 meta_finish(void)
900 {
901     if (metaBailiwick != NULL)
902 	Lst_Free(metaBailiwick);
903     free(metaBailiwickStr);
904     if (metaIgnorePaths != NULL)
905 	Lst_Free(metaIgnorePaths);
906     free(metaIgnorePathsStr);
907 }
908 
909 /*
910  * Fetch a full line from fp - growing bufp if needed
911  * Return length in bufp.
912  */
913 static int
914 fgetLine(char **bufp, size_t *szp, int o, FILE *fp)
915 {
916     char *buf = *bufp;
917     size_t bufsz = *szp;
918     struct stat fs;
919     int x;
920 
921     if (fgets(&buf[o], (int)bufsz - o, fp) != NULL) {
922     check_newline:
923 	x = o + (int)strlen(&buf[o]);
924 	if (buf[x - 1] == '\n')
925 	    return x;
926 	/*
927 	 * We need to grow the buffer.
928 	 * The meta file can give us a clue.
929 	 */
930 	if (fstat(fileno(fp), &fs) == 0) {
931 	    size_t newsz;
932 	    char *p;
933 
934 	    newsz = ROUNDUP(((size_t)fs.st_size / 2), BUFSIZ);
935 	    if (newsz <= bufsz)
936 		newsz = ROUNDUP((size_t)fs.st_size, BUFSIZ);
937 	    if (newsz <= bufsz)
938 		return x;		/* truncated */
939 	    DEBUG2(META, "growing buffer %zu -> %zu\n", bufsz, newsz);
940 	    p = bmake_realloc(buf, newsz);
941 	    if (p) {
942 		*bufp = buf = p;
943 		*szp = bufsz = newsz;
944 		/* fetch the rest */
945 		if (fgets(&buf[x], (int)bufsz - x, fp) == NULL)
946 		    return x;		/* truncated! */
947 		goto check_newline;
948 	    }
949 	}
950     }
951     return 0;
952 }
953 
954 /* Lst_ForEachUntil wants 1 to stop search */
955 static int
956 prefix_match(void *p, void *q)
957 {
958     const char *prefix = p;
959     const char *path = q;
960     size_t n = strlen(prefix);
961 
962     return strncmp(path, prefix, n) == 0;
963 }
964 
965 /* See if the path equals prefix or starts with "prefix/". */
966 static Boolean
967 path_starts_with(const char *path, const char *prefix)
968 {
969     size_t n = strlen(prefix);
970 
971     if (strncmp(path, prefix, n) != 0)
972 	return FALSE;
973     return path[n] == '\0' || path[n] == '/';
974 }
975 
976 static int
977 meta_ignore(GNode *gn, const char *p)
978 {
979     char fname[MAXPATHLEN];
980 
981     if (p == NULL)
982 	return TRUE;
983 
984     if (*p == '/') {
985 	cached_realpath(p, fname); /* clean it up */
986 	if (Lst_ForEachUntil(metaIgnorePaths, prefix_match, fname)) {
987 #ifdef DEBUG_META_MODE
988 	    DEBUG1(META, "meta_oodate: ignoring path: %s\n", p);
989 #endif
990 	    return TRUE;
991 	}
992     }
993 
994     if (metaIgnorePatterns) {
995 	const char *expr;
996 	char *pm;
997 
998 	Var_Set(".p.", p, gn);
999 	expr = "${" MAKE_META_IGNORE_PATTERNS ":@m@${.p.:M$m}@}";
1000 	(void)Var_Subst(expr, gn, VARE_WANTRES, &pm);
1001 	/* TODO: handle errors */
1002 	if (*pm) {
1003 #ifdef DEBUG_META_MODE
1004 	    DEBUG1(META, "meta_oodate: ignoring pattern: %s\n", p);
1005 #endif
1006 	    free(pm);
1007 	    return TRUE;
1008 	}
1009 	free(pm);
1010     }
1011 
1012     if (metaIgnoreFilter) {
1013 	char *fm;
1014 
1015 	/* skip if filter result is empty */
1016 	snprintf(fname, sizeof fname,
1017 		 "${%s:L:${%s:ts:}}",
1018 		 p, MAKE_META_IGNORE_FILTER);
1019 	(void)Var_Subst(fname, gn, VARE_WANTRES, &fm);
1020 	/* TODO: handle errors */
1021 	if (*fm == '\0') {
1022 #ifdef DEBUG_META_MODE
1023 	    DEBUG1(META, "meta_oodate: ignoring filtered: %s\n", p);
1024 #endif
1025 	    free(fm);
1026 	    return TRUE;
1027 	}
1028 	free(fm);
1029     }
1030     return FALSE;
1031 }
1032 
1033 /*
1034  * When running with 'meta' functionality, a target can be out-of-date
1035  * if any of the references in its meta data file is more recent.
1036  * We have to track the latestdir on a per-process basis.
1037  */
1038 #define LCWD_VNAME_FMT ".meta.%d.lcwd"
1039 #define LDIR_VNAME_FMT ".meta.%d.ldir"
1040 
1041 /*
1042  * It is possible that a .meta file is corrupted,
1043  * if we detect this we want to reproduce it.
1044  * Setting oodate TRUE will have that effect.
1045  */
1046 #define CHECK_VALID_META(p) if (!(p && *p)) { \
1047     warnx("%s: %d: malformed", fname, lineno); \
1048     oodate = TRUE; \
1049     continue; \
1050     }
1051 
1052 #define DEQUOTE(p) if (*p == '\'') {	\
1053     char *ep; \
1054     p++; \
1055     if ((ep = strchr(p, '\''))) \
1056 	*ep = '\0'; \
1057     }
1058 
1059 static void
1060 append_if_new(StringList *list, const char *str)
1061 {
1062     StringListNode *ln;
1063 
1064     for (ln = list->first; ln != NULL; ln = ln->next)
1065 	if (strcmp(ln->datum, str) == 0)
1066 	    return;
1067     Lst_Append(list, bmake_strdup(str));
1068 }
1069 
1070 Boolean
1071 meta_oodate(GNode *gn, Boolean oodate)
1072 {
1073     static char *tmpdir = NULL;
1074     static char cwd[MAXPATHLEN];
1075     char lcwd_vname[64];
1076     char ldir_vname[64];
1077     char lcwd[MAXPATHLEN];
1078     char latestdir[MAXPATHLEN];
1079     char fname[MAXPATHLEN];
1080     char fname1[MAXPATHLEN];
1081     char fname2[MAXPATHLEN];
1082     char fname3[MAXPATHLEN];
1083     const char *dname;
1084     const char *tname;
1085     char *p;
1086     char *cp;
1087     char *link_src;
1088     char *move_target;
1089     static size_t cwdlen = 0;
1090     static size_t tmplen = 0;
1091     FILE *fp;
1092     Boolean needOODATE = FALSE;
1093     StringList *missingFiles;
1094     Boolean have_filemon = FALSE;
1095     void *objdir_freeIt;
1096 
1097     if (oodate)
1098 	return oodate;		/* we're done */
1099 
1100     dname = Var_Value(".OBJDIR", gn, &objdir_freeIt);
1101     tname = GNode_VarTarget(gn);
1102 
1103     /* if this succeeds fname3 is realpath of dname */
1104     if (!meta_needed(gn, dname, fname3, FALSE))
1105 	goto oodate_out;
1106     dname = fname3;
1107 
1108     missingFiles = Lst_New();
1109 
1110     /*
1111      * We need to check if the target is out-of-date. This includes
1112      * checking if the expanded command has changed. This in turn
1113      * requires that all variables are set in the same way that they
1114      * would be if the target needs to be re-built.
1115      */
1116     Make_DoAllVar(gn);
1117 
1118     meta_name(fname, sizeof fname, dname, tname, dname);
1119 
1120 #ifdef DEBUG_META_MODE
1121     DEBUG1(META, "meta_oodate: %s\n", fname);
1122 #endif
1123 
1124     if ((fp = fopen(fname, "r")) != NULL) {
1125 	static char *buf = NULL;
1126 	static size_t bufsz;
1127 	int lineno = 0;
1128 	int lastpid = 0;
1129 	int pid;
1130 	int x;
1131 	StringListNode *cmdNode;
1132 	struct cached_stat cst;
1133 
1134 	if (buf == NULL) {
1135 	    bufsz = 8 * BUFSIZ;
1136 	    buf = bmake_malloc(bufsz);
1137 	}
1138 
1139 	if (cwdlen == 0) {
1140 	    if (getcwd(cwd, sizeof cwd) == NULL)
1141 		err(1, "Could not get current working directory");
1142 	    cwdlen = strlen(cwd);
1143 	}
1144 	strlcpy(lcwd, cwd, sizeof lcwd);
1145 	strlcpy(latestdir, cwd, sizeof latestdir);
1146 
1147 	if (tmpdir == NULL) {
1148 	    tmpdir = getTmpdir();
1149 	    tmplen = strlen(tmpdir);
1150 	}
1151 
1152 	/* we want to track all the .meta we read */
1153 	Var_Append(".MAKE.META.FILES", fname, VAR_GLOBAL);
1154 
1155 	cmdNode = gn->commands->first;
1156 	while (!oodate && (x = fgetLine(&buf, &bufsz, 0, fp)) > 0) {
1157 	    lineno++;
1158 	    if (buf[x - 1] == '\n')
1159 		buf[x - 1] = '\0';
1160 	    else {
1161 		warnx("%s: %d: line truncated at %u", fname, lineno, x);
1162 		oodate = TRUE;
1163 		break;
1164 	    }
1165 	    link_src = NULL;
1166 	    move_target = NULL;
1167 	    /* Find the start of the build monitor section. */
1168 	    if (!have_filemon) {
1169 		if (strncmp(buf, "-- filemon", 10) == 0) {
1170 		    have_filemon = TRUE;
1171 		    continue;
1172 		}
1173 		if (strncmp(buf, "# buildmon", 10) == 0) {
1174 		    have_filemon = TRUE;
1175 		    continue;
1176 		}
1177 	    }
1178 
1179 	    /* Delimit the record type. */
1180 	    p = buf;
1181 #ifdef DEBUG_META_MODE
1182 	    DEBUG3(META, "%s: %d: %s\n", fname, lineno, buf);
1183 #endif
1184 	    strsep(&p, " ");
1185 	    if (have_filemon) {
1186 		/*
1187 		 * We are in the 'filemon' output section.
1188 		 * Each record from filemon follows the general form:
1189 		 *
1190 		 * <key> <pid> <data>
1191 		 *
1192 		 * Where:
1193 		 * <key> is a single letter, denoting the syscall.
1194 		 * <pid> is the process that made the syscall.
1195 		 * <data> is the arguments (of interest).
1196 		 */
1197 		switch(buf[0]) {
1198 		case '#':		/* comment */
1199 		case 'V':		/* version */
1200 		    break;
1201 		default:
1202 		    /*
1203 		     * We need to track pathnames per-process.
1204 		     *
1205 		     * Each process run by make, starts off in the 'CWD'
1206 		     * recorded in the .meta file, if it chdirs ('C')
1207 		     * elsewhere we need to track that - but only for
1208 		     * that process.  If it forks ('F'), we initialize
1209 		     * the child to have the same cwd as its parent.
1210 		     *
1211 		     * We also need to track the 'latestdir' of
1212 		     * interest.  This is usually the same as cwd, but
1213 		     * not if a process is reading directories.
1214 		     *
1215 		     * Each time we spot a different process ('pid')
1216 		     * we save the current value of 'latestdir' in a
1217 		     * variable qualified by 'lastpid', and
1218 		     * re-initialize 'latestdir' to any pre-saved
1219 		     * value for the current 'pid' and 'CWD' if none.
1220 		     */
1221 		    CHECK_VALID_META(p);
1222 		    pid = atoi(p);
1223 		    if (pid > 0 && pid != lastpid) {
1224 			const char *ldir;
1225 			void *tp;
1226 
1227 			if (lastpid > 0) {
1228 			    /* We need to remember these. */
1229 			    Var_Set(lcwd_vname, lcwd, VAR_GLOBAL);
1230 			    Var_Set(ldir_vname, latestdir, VAR_GLOBAL);
1231 			}
1232 			snprintf(lcwd_vname, sizeof lcwd_vname, LCWD_VNAME_FMT, pid);
1233 			snprintf(ldir_vname, sizeof ldir_vname, LDIR_VNAME_FMT, pid);
1234 			lastpid = pid;
1235 			ldir = Var_Value(ldir_vname, VAR_GLOBAL, &tp);
1236 			if (ldir) {
1237 			    strlcpy(latestdir, ldir, sizeof latestdir);
1238 			    bmake_free(tp);
1239 			}
1240 			ldir = Var_Value(lcwd_vname, VAR_GLOBAL, &tp);
1241 			if (ldir) {
1242 			    strlcpy(lcwd, ldir, sizeof lcwd);
1243 			    bmake_free(tp);
1244 			}
1245 		    }
1246 		    /* Skip past the pid. */
1247 		    if (strsep(&p, " ") == NULL)
1248 			continue;
1249 #ifdef DEBUG_META_MODE
1250 		    if (DEBUG(META))
1251 			debug_printf("%s: %d: %d: %c: cwd=%s lcwd=%s ldir=%s\n",
1252 				     fname, lineno,
1253 				     pid, buf[0], cwd, lcwd, latestdir);
1254 #endif
1255 		    break;
1256 		}
1257 
1258 		CHECK_VALID_META(p);
1259 
1260 		/* Process according to record type. */
1261 		switch (buf[0]) {
1262 		case 'X':		/* eXit */
1263 		    Var_Delete(lcwd_vname, VAR_GLOBAL);
1264 		    Var_Delete(ldir_vname, VAR_GLOBAL);
1265 		    lastpid = 0;	/* no need to save ldir_vname */
1266 		    break;
1267 
1268 		case 'F':		/* [v]Fork */
1269 		    {
1270 			char cldir[64];
1271 			int child;
1272 
1273 			child = atoi(p);
1274 			if (child > 0) {
1275 			    snprintf(cldir, sizeof cldir, LCWD_VNAME_FMT, child);
1276 			    Var_Set(cldir, lcwd, VAR_GLOBAL);
1277 			    snprintf(cldir, sizeof cldir, LDIR_VNAME_FMT, child);
1278 			    Var_Set(cldir, latestdir, VAR_GLOBAL);
1279 #ifdef DEBUG_META_MODE
1280 			    if (DEBUG(META))
1281 				debug_printf(
1282 					"%s: %d: %d: cwd=%s lcwd=%s ldir=%s\n",
1283 					fname, lineno,
1284 					child, cwd, lcwd, latestdir);
1285 #endif
1286 			}
1287 		    }
1288 		    break;
1289 
1290 		case 'C':		/* Chdir */
1291 		    /* Update lcwd and latest directory. */
1292 		    strlcpy(latestdir, p, sizeof latestdir);
1293 		    strlcpy(lcwd, p, sizeof lcwd);
1294 		    Var_Set(lcwd_vname, lcwd, VAR_GLOBAL);
1295 		    Var_Set(ldir_vname, lcwd, VAR_GLOBAL);
1296 #ifdef DEBUG_META_MODE
1297 		    DEBUG4(META, "%s: %d: cwd=%s ldir=%s\n",
1298 			   fname, lineno, cwd, lcwd);
1299 #endif
1300 		    break;
1301 
1302 		case 'M':		/* renaMe */
1303 		    /*
1304 		     * For 'M'oves we want to check
1305 		     * the src as for 'R'ead
1306 		     * and the target as for 'W'rite.
1307 		     */
1308 		    cp = p;		/* save this for a second */
1309 		    /* now get target */
1310 		    if (strsep(&p, " ") == NULL)
1311 			continue;
1312 		    CHECK_VALID_META(p);
1313 		    move_target = p;
1314 		    p = cp;
1315 		    /* 'L' and 'M' put single quotes around the args */
1316 		    DEQUOTE(p);
1317 		    DEQUOTE(move_target);
1318 		    /* FALLTHROUGH */
1319 		case 'D':		/* unlink */
1320 		    if (*p == '/') {
1321 			/* remove any missingFiles entries that match p */
1322 			StringListNode *ln = missingFiles->first;
1323 			while (ln != NULL) {
1324 			    StringListNode *next = ln->next;
1325 			    if (path_starts_with(ln->datum, p)) {
1326 				free(ln->datum);
1327 				Lst_Remove(missingFiles, ln);
1328 			    }
1329 			    ln = next;
1330 			}
1331 		    }
1332 		    if (buf[0] == 'M') {
1333 			/* the target of the mv is a file 'W'ritten */
1334 #ifdef DEBUG_META_MODE
1335 			DEBUG2(META, "meta_oodate: M %s -> %s\n",
1336 			       p, move_target);
1337 #endif
1338 			p = move_target;
1339 			goto check_write;
1340 		    }
1341 		    break;
1342 		case 'L':		/* Link */
1343 		    /*
1344 		     * For 'L'inks check
1345 		     * the src as for 'R'ead
1346 		     * and the target as for 'W'rite.
1347 		     */
1348 		    link_src = p;
1349 		    /* now get target */
1350 		    if (strsep(&p, " ") == NULL)
1351 			continue;
1352 		    CHECK_VALID_META(p);
1353 		    /* 'L' and 'M' put single quotes around the args */
1354 		    DEQUOTE(p);
1355 		    DEQUOTE(link_src);
1356 #ifdef DEBUG_META_MODE
1357 		    DEBUG2(META, "meta_oodate: L %s -> %s\n", link_src, p);
1358 #endif
1359 		    /* FALLTHROUGH */
1360 		case 'W':		/* Write */
1361 		check_write:
1362 		    /*
1363 		     * If a file we generated within our bailiwick
1364 		     * but outside of .OBJDIR is missing,
1365 		     * we need to do it again.
1366 		     */
1367 		    /* ignore non-absolute paths */
1368 		    if (*p != '/')
1369 			break;
1370 
1371 		    if (Lst_IsEmpty(metaBailiwick))
1372 			break;
1373 
1374 		    /* ignore cwd - normal dependencies handle those */
1375 		    if (strncmp(p, cwd, cwdlen) == 0)
1376 			break;
1377 
1378 		    if (!Lst_ForEachUntil(metaBailiwick, prefix_match, p))
1379 			break;
1380 
1381 		    /* tmpdir might be within */
1382 		    if (tmplen > 0 && strncmp(p, tmpdir, tmplen) == 0)
1383 			break;
1384 
1385 		    /* ignore anything containing the string "tmp" */
1386 		    /* XXX: The arguments to strstr must be swapped. */
1387 		    if ((strstr("tmp", p)))
1388 			break;
1389 
1390 		    if ((link_src != NULL && cached_lstat(p, &cst) < 0) ||
1391 			(link_src == NULL && cached_stat(p, &cst) < 0)) {
1392 			if (!meta_ignore(gn, p))
1393 			    append_if_new(missingFiles, p);
1394 		    }
1395 		    break;
1396 		check_link_src:
1397 		    p = link_src;
1398 		    link_src = NULL;
1399 #ifdef DEBUG_META_MODE
1400 		    DEBUG1(META, "meta_oodate: L src %s\n", p);
1401 #endif
1402 		    /* FALLTHROUGH */
1403 		case 'R':		/* Read */
1404 		case 'E':		/* Exec */
1405 		    /*
1406 		     * Check for runtime files that can't
1407 		     * be part of the dependencies because
1408 		     * they are _expected_ to change.
1409 		     */
1410 		    if (meta_ignore(gn, p))
1411 			break;
1412 
1413 		    /*
1414 		     * The rest of the record is the file name.
1415 		     * Check if it's not an absolute path.
1416 		     */
1417 		    {
1418 			char *sdirs[4];
1419 			char **sdp;
1420 			int sdx = 0;
1421 			int found = 0;
1422 
1423 			if (*p == '/') {
1424 			    sdirs[sdx++] = p; /* done */
1425 			} else {
1426 			    if (strcmp(".", p) == 0)
1427 				continue;  /* no point */
1428 
1429 			    /* Check vs latestdir */
1430 			    snprintf(fname1, sizeof fname1, "%s/%s", latestdir, p);
1431 			    sdirs[sdx++] = fname1;
1432 
1433 			    if (strcmp(latestdir, lcwd) != 0) {
1434 				/* Check vs lcwd */
1435 				snprintf(fname2, sizeof fname2, "%s/%s", lcwd, p);
1436 				sdirs[sdx++] = fname2;
1437 			    }
1438 			    if (strcmp(lcwd, cwd) != 0) {
1439 				/* Check vs cwd */
1440 				snprintf(fname3, sizeof fname3, "%s/%s", cwd, p);
1441 				sdirs[sdx++] = fname3;
1442 			    }
1443 			}
1444 			sdirs[sdx++] = NULL;
1445 
1446 			for (sdp = sdirs; *sdp && !found; sdp++) {
1447 #ifdef DEBUG_META_MODE
1448 			    DEBUG3(META, "%s: %d: looking for: %s\n",
1449 				   fname, lineno, *sdp);
1450 #endif
1451 			    if (cached_stat(*sdp, &cst) == 0) {
1452 				found = 1;
1453 				p = *sdp;
1454 			    }
1455 			}
1456 			if (found) {
1457 #ifdef DEBUG_META_MODE
1458 			    DEBUG3(META, "%s: %d: found: %s\n",
1459 				   fname, lineno, p);
1460 #endif
1461 			    if (!S_ISDIR(cst.cst_mode) &&
1462 				cst.cst_mtime > gn->mtime) {
1463 				DEBUG3(META, "%s: %d: file '%s' is newer than the target...\n",
1464 				       fname, lineno, p);
1465 				oodate = TRUE;
1466 			    } else if (S_ISDIR(cst.cst_mode)) {
1467 				/* Update the latest directory. */
1468 				cached_realpath(p, latestdir);
1469 			    }
1470 			} else if (errno == ENOENT && *p == '/' &&
1471 				   strncmp(p, cwd, cwdlen) != 0) {
1472 			    /*
1473 			     * A referenced file outside of CWD is missing.
1474 			     * We cannot catch every eventuality here...
1475 			     */
1476 			    append_if_new(missingFiles, p);
1477 			}
1478 		    }
1479 		    if (buf[0] == 'E') {
1480 			/* previous latestdir is no longer relevant */
1481 			strlcpy(latestdir, lcwd, sizeof latestdir);
1482 		    }
1483 		    break;
1484 		default:
1485 		    break;
1486 		}
1487 		if (!oodate && buf[0] == 'L' && link_src != NULL)
1488 		    goto check_link_src;
1489 	    } else if (strcmp(buf, "CMD") == 0) {
1490 		/*
1491 		 * Compare the current command with the one in the
1492 		 * meta data file.
1493 		 */
1494 		if (cmdNode == NULL) {
1495 		    DEBUG2(META, "%s: %d: there were more build commands in the meta data file than there are now...\n",
1496 			   fname, lineno);
1497 		    oodate = TRUE;
1498 		} else {
1499 		    char *cmd = cmdNode->datum;
1500 		    Boolean hasOODATE = FALSE;
1501 
1502 		    if (strstr(cmd, "$?"))
1503 			hasOODATE = TRUE;
1504 		    else if ((cp = strstr(cmd, ".OODATE"))) {
1505 			/* check for $[{(].OODATE[:)}] */
1506 			if (cp > cmd + 2 && cp[-2] == '$')
1507 			    hasOODATE = TRUE;
1508 		    }
1509 		    if (hasOODATE) {
1510 			needOODATE = TRUE;
1511 			DEBUG2(META, "%s: %d: cannot compare command using .OODATE\n",
1512 			       fname, lineno);
1513 		    }
1514 		    (void)Var_Subst(cmd, gn, VARE_WANTRES|VARE_UNDEFERR, &cmd);
1515 		    /* TODO: handle errors */
1516 
1517 		    if ((cp = strchr(cmd, '\n'))) {
1518 			int n;
1519 
1520 			/*
1521 			 * This command contains newlines, we need to
1522 			 * fetch more from the .meta file before we
1523 			 * attempt a comparison.
1524 			 */
1525 			/* first put the newline back at buf[x - 1] */
1526 			buf[x - 1] = '\n';
1527 			do {
1528 			    /* now fetch the next line */
1529 			    if ((n = fgetLine(&buf, &bufsz, x, fp)) <= 0)
1530 				break;
1531 			    x = n;
1532 			    lineno++;
1533 			    if (buf[x - 1] != '\n') {
1534 				warnx("%s: %d: line truncated at %u", fname, lineno, x);
1535 				break;
1536 			    }
1537 			    cp = strchr(++cp, '\n');
1538 			} while (cp);
1539 			if (buf[x - 1] == '\n')
1540 			    buf[x - 1] = '\0';
1541 		    }
1542 		    if (p != NULL &&
1543 			!hasOODATE &&
1544 			!(gn->type & OP_NOMETA_CMP) &&
1545 			(strcmp(p, cmd) != 0)) {
1546 			DEBUG4(META, "%s: %d: a build command has changed\n%s\nvs\n%s\n",
1547 			       fname, lineno, p, cmd);
1548 			if (!metaIgnoreCMDs)
1549 			    oodate = TRUE;
1550 		    }
1551 		    free(cmd);
1552 		    cmdNode = cmdNode->next;
1553 		}
1554 	    } else if (strcmp(buf, "CWD") == 0) {
1555 		/*
1556 		 * Check if there are extra commands now
1557 		 * that weren't in the meta data file.
1558 		 */
1559 		if (!oodate && cmdNode != NULL) {
1560 		    DEBUG2(META, "%s: %d: there are extra build commands now that weren't in the meta data file\n",
1561 			   fname, lineno);
1562 		    oodate = TRUE;
1563 		}
1564 		CHECK_VALID_META(p);
1565 		if (strcmp(p, cwd) != 0) {
1566 		    DEBUG4(META, "%s: %d: the current working directory has changed from '%s' to '%s'\n",
1567 			   fname, lineno, p, curdir);
1568 		    oodate = TRUE;
1569 		}
1570 	    }
1571 	}
1572 
1573 	fclose(fp);
1574 	if (!Lst_IsEmpty(missingFiles)) {
1575 	    DEBUG2(META, "%s: missing files: %s...\n",
1576 		   fname, (char *)missingFiles->first->datum);
1577 	    oodate = TRUE;
1578 	}
1579 	if (!oodate && !have_filemon && filemonMissing) {
1580 	    DEBUG1(META, "%s: missing filemon data\n", fname);
1581 	    oodate = TRUE;
1582 	}
1583     } else {
1584 	if (writeMeta && (metaMissing || (gn->type & OP_META))) {
1585 	    cp = NULL;
1586 
1587 	    /* if target is in .CURDIR we do not need a meta file */
1588 	    if (gn->path && (cp = strrchr(gn->path, '/')) && cp > gn->path) {
1589 		if (strncmp(curdir, gn->path, (size_t)(cp - gn->path)) != 0) {
1590 		    cp = NULL;		/* not in .CURDIR */
1591 		}
1592 	    }
1593 	    if (cp == NULL) {
1594 		DEBUG1(META, "%s: required but missing\n", fname);
1595 		oodate = TRUE;
1596 		needOODATE = TRUE;	/* assume the worst */
1597 	    }
1598 	}
1599     }
1600 
1601     Lst_Destroy(missingFiles, free);
1602 
1603     if (oodate && needOODATE) {
1604 	/*
1605 	 * Target uses .OODATE which is empty; or we wouldn't be here.
1606 	 * We have decided it is oodate, so .OODATE needs to be set.
1607 	 * All we can sanely do is set it to .ALLSRC.
1608 	 */
1609 	Var_Delete(OODATE, gn);
1610 	Var_Set(OODATE, GNode_VarAllsrc(gn), gn);
1611     }
1612 
1613  oodate_out:
1614     bmake_free(objdir_freeIt);
1615     return oodate;
1616 }
1617 
1618 /* support for compat mode */
1619 
1620 static int childPipe[2];
1621 
1622 void
1623 meta_compat_start(void)
1624 {
1625 #ifdef USE_FILEMON_ONCE
1626     /*
1627      * We need to re-open filemon for each cmd.
1628      */
1629     BuildMon *pbm = &Mybm;
1630 
1631     if (pbm->mfp != NULL && useFilemon) {
1632 	meta_open_filemon(pbm);
1633     } else {
1634 	pbm->mon_fd = -1;
1635 	pbm->filemon = NULL;
1636     }
1637 #endif
1638     if (pipe(childPipe) < 0)
1639 	Punt("Cannot create pipe: %s", strerror(errno));
1640     /* Set close-on-exec flag for both */
1641     (void)fcntl(childPipe[0], F_SETFD, FD_CLOEXEC);
1642     (void)fcntl(childPipe[1], F_SETFD, FD_CLOEXEC);
1643 }
1644 
1645 void
1646 meta_compat_child(void)
1647 {
1648     meta_job_child(NULL);
1649     if (dup2(childPipe[1], 1) < 0 || dup2(1, 2) < 0)
1650 	execDie("dup2", "pipe");
1651 }
1652 
1653 void
1654 meta_compat_parent(pid_t child)
1655 {
1656     int outfd, metafd, maxfd, nfds;
1657     char buf[BUFSIZ+1];
1658     fd_set readfds;
1659 
1660     meta_job_parent(NULL, child);
1661     close(childPipe[1]);			/* child side */
1662     outfd = childPipe[0];
1663 #ifdef USE_FILEMON
1664     metafd = Mybm.filemon ? filemon_readfd(Mybm.filemon) : -1;
1665 #else
1666     metafd = -1;
1667 #endif
1668     maxfd = -1;
1669     if (outfd > maxfd)
1670 	    maxfd = outfd;
1671     if (metafd > maxfd)
1672 	    maxfd = metafd;
1673 
1674     while (outfd != -1 || metafd != -1) {
1675 	FD_ZERO(&readfds);
1676 	if (outfd != -1) {
1677 	    FD_SET(outfd, &readfds);
1678 	}
1679 	if (metafd != -1) {
1680 	    FD_SET(metafd, &readfds);
1681 	}
1682 	nfds = select(maxfd + 1, &readfds, NULL, NULL, NULL);
1683 	if (nfds == -1) {
1684 	    if (errno == EINTR)
1685 		continue;
1686 	    err(1, "select");
1687 	}
1688 
1689 	if (outfd != -1 && FD_ISSET(outfd, &readfds)) do {
1690 	    /* XXX this is not line-buffered */
1691 	    ssize_t nread = read(outfd, buf, sizeof buf - 1);
1692 	    if (nread == -1)
1693 		err(1, "read");
1694 	    if (nread == 0) {
1695 		close(outfd);
1696 		outfd = -1;
1697 		break;
1698 	    }
1699 	    fwrite(buf, 1, (size_t)nread, stdout);
1700 	    fflush(stdout);
1701 	    buf[nread] = '\0';
1702 	    meta_job_output(NULL, buf, "");
1703 	} while (0);
1704 	if (metafd != -1 && FD_ISSET(metafd, &readfds)) {
1705 	    if (meta_job_event(NULL) <= 0)
1706 		metafd = -1;
1707 	}
1708     }
1709 }
1710 
1711 #endif	/* USE_META */
1712