xref: /netbsd-src/usr.bin/make/meta.c (revision 8ecbf5f02b752fcb7debe1a8fab1dc82602bc760)
1 /*      $NetBSD: meta.c,v 1.113 2020/09/02 04:08:54 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 #include <libgen.h>
40 #include <errno.h>
41 #if !defined(HAVE_CONFIG_H) || defined(HAVE_ERR_H)
42 #include <err.h>
43 #endif
44 
45 #include "make.h"
46 #include "dir.h"
47 #include "job.h"
48 
49 #ifdef USE_FILEMON
50 #include "filemon/filemon.h"
51 #endif
52 
53 static BuildMon Mybm;			/* for compat */
54 static Lst metaBailiwick;		/* our scope of control */
55 static char *metaBailiwickStr;		/* string storage for the list */
56 static Lst metaIgnorePaths;		/* paths we deliberately ignore */
57 static char *metaIgnorePathsStr;	/* string storage for the list */
58 
59 #ifndef MAKE_META_IGNORE_PATHS
60 #define MAKE_META_IGNORE_PATHS ".MAKE.META.IGNORE_PATHS"
61 #endif
62 #ifndef MAKE_META_IGNORE_PATTERNS
63 #define MAKE_META_IGNORE_PATTERNS ".MAKE.META.IGNORE_PATTERNS"
64 #endif
65 #ifndef MAKE_META_IGNORE_FILTER
66 #define MAKE_META_IGNORE_FILTER ".MAKE.META.IGNORE_FILTER"
67 #endif
68 
69 Boolean useMeta = FALSE;
70 static Boolean useFilemon = FALSE;
71 static Boolean writeMeta = FALSE;
72 static Boolean metaMissing = FALSE;	/* oodate if missing */
73 static Boolean filemonMissing = FALSE;	/* oodate if missing */
74 static Boolean metaEnv = FALSE;		/* don't save env unless asked */
75 static Boolean metaVerbose = FALSE;
76 static Boolean metaIgnoreCMDs = FALSE;	/* ignore CMDs in .meta files */
77 static Boolean metaIgnorePatterns = FALSE; /* do we need to do pattern matches */
78 static Boolean metaIgnoreFilter = FALSE;   /* do we have more complex filtering? */
79 static Boolean metaCurdirOk = FALSE;	/* write .meta in .CURDIR Ok? */
80 static Boolean metaSilent = FALSE;	/* if we have a .meta be SILENT */
81 
82 extern Boolean forceJobs;
83 extern Boolean comatMake;
84 extern char    **environ;
85 
86 #define	MAKE_META_PREFIX	".MAKE.META.PREFIX"
87 
88 #ifndef N2U
89 # define N2U(n, u)   (((n) + ((u) - 1)) / (u))
90 #endif
91 #ifndef ROUNDUP
92 # define ROUNDUP(n, u)   (N2U((n), (u)) * (u))
93 #endif
94 
95 #if !defined(HAVE_STRSEP)
96 # define strsep(s, d) stresep((s), (d), 0)
97 #endif
98 
99 /*
100  * Filemon is a kernel module which snoops certain syscalls.
101  *
102  * C chdir
103  * E exec
104  * F [v]fork
105  * L [sym]link
106  * M rename
107  * R read
108  * W write
109  * S stat
110  *
111  * See meta_oodate below - we mainly care about 'E' and 'R'.
112  *
113  * We can still use meta mode without filemon, but
114  * the benefits are more limited.
115  */
116 #ifdef USE_FILEMON
117 
118 /*
119  * Open the filemon device.
120  */
121 static void
122 meta_open_filemon(BuildMon *pbm)
123 {
124     int dupfd;
125 
126     pbm->mon_fd = -1;
127     pbm->filemon = NULL;
128     if (!useFilemon || !pbm->mfp)
129 	return;
130 
131     pbm->filemon = filemon_open();
132     if (pbm->filemon == NULL) {
133 	useFilemon = FALSE;
134 	warn("Could not open filemon %s", filemon_path());
135 	return;
136     }
137 
138     /*
139      * We use a file outside of '.'
140      * to avoid a FreeBSD kernel bug where unlink invalidates
141      * cwd causing getcwd to do a lot more work.
142      * We only care about the descriptor.
143      */
144     pbm->mon_fd = mkTempFile("filemon.XXXXXX", NULL);
145     if ((dupfd = dup(pbm->mon_fd)) == -1) {
146 	err(1, "Could not dup filemon output!");
147     }
148     (void)fcntl(dupfd, F_SETFD, FD_CLOEXEC);
149     if (filemon_setfd(pbm->filemon, dupfd) == -1) {
150 	err(1, "Could not set filemon file descriptor!");
151     }
152     /* we don't need these once we exec */
153     (void)fcntl(pbm->mon_fd, F_SETFD, FD_CLOEXEC);
154 }
155 
156 /*
157  * Read the build monitor output file and write records to the target's
158  * metadata file.
159  */
160 static int
161 filemon_read(FILE *mfp, int fd)
162 {
163     char buf[BUFSIZ];
164     int n;
165     int error;
166 
167     /* Check if we're not writing to a meta data file.*/
168     if (mfp == NULL) {
169 	if (fd >= 0)
170 	    close(fd);			/* not interested */
171 	return 0;
172     }
173     /* rewind */
174     if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
175 	error = errno;
176 	warn("Could not rewind filemon");
177 	fprintf(mfp, "\n");
178     } else {
179 	error = 0;
180 	fprintf(mfp, "\n-- filemon acquired metadata --\n");
181 
182 	while ((n = read(fd, buf, sizeof(buf))) > 0) {
183 	    if ((int)fwrite(buf, 1, n, mfp) < n)
184 		error = EIO;
185 	}
186     }
187     fflush(mfp);
188     if (close(fd) < 0)
189 	error = errno;
190     return error;
191 }
192 #endif
193 
194 /*
195  * when realpath() fails,
196  * we use this, to clean up ./ and ../
197  */
198 static void
199 eat_dots(char *buf, size_t bufsz, int dots)
200 {
201     char *cp;
202     char *cp2;
203     const char *eat;
204     size_t eatlen;
205 
206     switch (dots) {
207     case 1:
208 	eat = "/./";
209 	eatlen = 2;
210 	break;
211     case 2:
212 	eat = "/../";
213 	eatlen = 3;
214 	break;
215     default:
216 	return;
217     }
218 
219     do {
220 	cp = strstr(buf, eat);
221 	if (cp) {
222 	    cp2 = cp + eatlen;
223 	    if (dots == 2 && cp > buf) {
224 		do {
225 		    cp--;
226 		} while (cp > buf && *cp != '/');
227 	    }
228 	    if (*cp == '/') {
229 		strlcpy(cp, cp2, bufsz - (cp - buf));
230 	    } else {
231 		return;			/* can't happen? */
232 	    }
233 	}
234     } while (cp);
235 }
236 
237 static char *
238 meta_name(struct GNode *gn, char *mname, size_t mnamelen,
239 	  const char *dname,
240 	  const char *tname,
241 	  const char *cwd)
242 {
243     char buf[MAXPATHLEN];
244     char *rp;
245     char *cp;
246     char *tp;
247     char *dtp;
248     size_t ldname;
249 
250     /*
251      * Weed out relative paths from the target file name.
252      * We have to be careful though since if target is a
253      * symlink, the result will be unstable.
254      * So we use realpath() just to get the dirname, and leave the
255      * basename as given to us.
256      */
257     if ((cp = strrchr(tname, '/'))) {
258 	if (cached_realpath(tname, buf)) {
259 	    if ((rp = strrchr(buf, '/'))) {
260 		rp++;
261 		cp++;
262 		if (strcmp(cp, rp) != 0)
263 		    strlcpy(rp, cp, sizeof(buf) - (rp - buf));
264 	    }
265 	    tname = buf;
266 	} else {
267 	    /*
268 	     * We likely have a directory which is about to be made.
269 	     * We pretend realpath() succeeded, to have a chance
270 	     * of generating the same meta file name that we will
271 	     * next time through.
272 	     */
273 	    if (tname[0] == '/') {
274 		strlcpy(buf, tname, sizeof(buf));
275 	    } else {
276 		snprintf(buf, sizeof(buf), "%s/%s", cwd, tname);
277 	    }
278 	    eat_dots(buf, sizeof(buf), 1);	/* ./ */
279 	    eat_dots(buf, sizeof(buf), 2);	/* ../ */
280 	    tname = buf;
281 	}
282     }
283     /* on some systems dirname may modify its arg */
284     tp = bmake_strdup(tname);
285     dtp = dirname(tp);
286     if (strcmp(dname, dtp) == 0)
287 	snprintf(mname, mnamelen, "%s.meta", tname);
288     else {
289 	ldname = strlen(dname);
290 	if (strncmp(dname, dtp, ldname) == 0 && dtp[ldname] == '/')
291 	    snprintf(mname, mnamelen, "%s/%s.meta", dname, &tname[ldname+1]);
292 	else
293 	    snprintf(mname, mnamelen, "%s/%s.meta", dname, tname);
294 
295 	/*
296 	 * Replace path separators in the file name after the
297 	 * current object directory path.
298 	 */
299 	cp = mname + strlen(dname) + 1;
300 
301 	while (*cp != '\0') {
302 	    if (*cp == '/')
303 		*cp = '_';
304 	    cp++;
305 	}
306     }
307     free(tp);
308     return mname;
309 }
310 
311 /*
312  * Return true if running ${.MAKE}
313  * Bypassed if target is flagged .MAKE
314  */
315 static int
316 is_submake(void *cmdp, void *gnp)
317 {
318     static const char *p_make = NULL;
319     static int p_len;
320     char  *cmd = cmdp;
321     GNode *gn = gnp;
322     char *mp = NULL;
323     char *cp;
324     char *cp2;
325     int rc = 0;				/* keep looking */
326 
327     if (!p_make) {
328 	p_make = Var_Value(".MAKE", gn, &cp);
329 	p_len = strlen(p_make);
330     }
331     cp = strchr(cmd, '$');
332     if ((cp)) {
333 	mp = Var_Subst(cmd, gn, VARE_WANTRES);
334 	cmd = mp;
335     }
336     cp2 = strstr(cmd, p_make);
337     if ((cp2)) {
338 	switch (cp2[p_len]) {
339 	case '\0':
340 	case ' ':
341 	case '\t':
342 	case '\n':
343 	    rc = 1;
344 	    break;
345 	}
346 	if (cp2 > cmd && rc > 0) {
347 	    switch (cp2[-1]) {
348 	    case ' ':
349 	    case '\t':
350 	    case '\n':
351 		break;
352 	    default:
353 		rc = 0;			/* no match */
354 		break;
355 	    }
356 	}
357     }
358     free(mp);
359     return rc;
360 }
361 
362 typedef struct meta_file_s {
363     FILE *fp;
364     GNode *gn;
365 } meta_file_t;
366 
367 static int
368 printCMD(void *cmdp, void *mfpp)
369 {
370     meta_file_t *mfp = mfpp;
371     char *cmd = cmdp;
372     char *cmd_freeIt = NULL;
373 
374     if (strchr(cmd, '$')) {
375 	cmd = cmd_freeIt = Var_Subst(cmd, mfp->gn, VARE_WANTRES);
376     }
377     fprintf(mfp->fp, "CMD %s\n", cmd);
378     free(cmd_freeIt);
379     return 0;
380 }
381 
382 /*
383  * Certain node types never get a .meta file
384  */
385 #define SKIP_META_TYPE(_type) do { \
386     if ((gn->type & __CONCAT(OP_, _type))) {	\
387 	if (verbose) { \
388 	    fprintf(debug_file, "Skipping meta for %s: .%s\n", \
389 		    gn->name, __STRING(_type));		       \
390 	} \
391 	return FALSE; \
392     } \
393 } while (0)
394 
395 
396 /*
397  * Do we need/want a .meta file ?
398  */
399 static Boolean
400 meta_needed(GNode *gn, const char *dname, const char *tname,
401 	     char *objdir, int verbose)
402 {
403     struct make_stat mst;
404 
405     if (verbose)
406 	verbose = DEBUG(META);
407 
408     /* This may be a phony node which we don't want meta data for... */
409     /* Skip .meta for .BEGIN, .END, .ERROR etc as well. */
410     /* Or it may be explicitly flagged as .NOMETA */
411     SKIP_META_TYPE(NOMETA);
412     /* Unless it is explicitly flagged as .META */
413     if (!(gn->type & OP_META)) {
414 	SKIP_META_TYPE(PHONY);
415 	SKIP_META_TYPE(SPECIAL);
416 	SKIP_META_TYPE(MAKE);
417     }
418 
419     /* Check if there are no commands to execute. */
420     if (Lst_IsEmpty(gn->commands)) {
421 	if (verbose)
422 	    fprintf(debug_file, "Skipping meta for %s: no commands\n",
423 		    gn->name);
424 	return FALSE;
425     }
426     if ((gn->type & (OP_META|OP_SUBMAKE)) == OP_SUBMAKE) {
427 	/* OP_SUBMAKE is a bit too aggressive */
428 	if (Lst_ForEach(gn->commands, is_submake, gn)) {
429 	    if (DEBUG(META))
430 		fprintf(debug_file, "Skipping meta for %s: .SUBMAKE\n",
431 			gn->name);
432 	    return FALSE;
433 	}
434     }
435 
436     /* The object directory may not exist. Check it.. */
437     if (cached_stat(dname, &mst) != 0) {
438 	if (verbose)
439 	    fprintf(debug_file, "Skipping meta for %s: no .OBJDIR\n",
440 		    gn->name);
441 	return FALSE;
442     }
443 
444     /* make sure these are canonical */
445     if (cached_realpath(dname, objdir))
446 	dname = objdir;
447 
448     /* If we aren't in the object directory, don't create a meta file. */
449     if (!metaCurdirOk && strcmp(curdir, dname) == 0) {
450 	if (verbose)
451 	    fprintf(debug_file, "Skipping meta for %s: .OBJDIR == .CURDIR\n",
452 		    gn->name);
453 	return FALSE;
454     }
455     return TRUE;
456 }
457 
458 
459 static FILE *
460 meta_create(BuildMon *pbm, GNode *gn)
461 {
462     meta_file_t mf;
463     char buf[MAXPATHLEN];
464     char objdir[MAXPATHLEN];
465     char **ptr;
466     const char *dname;
467     const char *tname;
468     char *fname;
469     const char *cp;
470     char *p[5];				/* >= possible uses */
471     int i;
472 
473     mf.fp = NULL;
474     i = 0;
475 
476     dname = Var_Value(".OBJDIR", gn, &p[i++]);
477     tname = Var_Value(TARGET, gn, &p[i++]);
478 
479     /* if this succeeds objdir is realpath of dname */
480     if (!meta_needed(gn, dname, tname, objdir, TRUE))
481 	goto out;
482     dname = objdir;
483 
484     if (metaVerbose) {
485 	char *mp;
486 
487 	/* Describe the target we are building */
488 	mp = Var_Subst("${" MAKE_META_PREFIX "}", gn, VARE_WANTRES);
489 	if (*mp)
490 	    fprintf(stdout, "%s\n", mp);
491 	free(mp);
492     }
493     /* Get the basename of the target */
494     if ((cp = strrchr(tname, '/')) == NULL) {
495 	cp = tname;
496     } else {
497 	cp++;
498     }
499 
500     fflush(stdout);
501 
502     if (!writeMeta)
503 	/* Don't create meta data. */
504 	goto out;
505 
506     fname = meta_name(gn, pbm->meta_fname, sizeof(pbm->meta_fname),
507 		      dname, tname, objdir);
508 
509 #ifdef DEBUG_META_MODE
510     if (DEBUG(META))
511 	fprintf(debug_file, "meta_create: %s\n", fname);
512 #endif
513 
514     if ((mf.fp = fopen(fname, "w")) == NULL)
515 	err(1, "Could not open meta file '%s'", fname);
516 
517     fprintf(mf.fp, "# Meta data file %s\n", fname);
518 
519     mf.gn = gn;
520 
521     Lst_ForEach(gn->commands, printCMD, &mf);
522 
523     fprintf(mf.fp, "CWD %s\n", getcwd(buf, sizeof(buf)));
524     fprintf(mf.fp, "TARGET %s\n", tname);
525     cp = Var_Value(".OODATE", gn, &p[i++]);
526     if (cp && *cp) {
527 	    fprintf(mf.fp, "OODATE %s\n", cp);
528     }
529     if (metaEnv) {
530 	for (ptr = environ; *ptr != NULL; ptr++)
531 	    fprintf(mf.fp, "ENV %s\n", *ptr);
532     }
533 
534     fprintf(mf.fp, "-- command output --\n");
535     fflush(mf.fp);
536 
537     Var_Append(".MAKE.META.FILES", fname, VAR_GLOBAL);
538     Var_Append(".MAKE.META.CREATED", fname, VAR_GLOBAL);
539 
540     gn->type |= OP_META;		/* in case anyone wants to know */
541     if (metaSilent) {
542 	    gn->type |= OP_SILENT;
543     }
544  out:
545     for (i--; i >= 0; i--) {
546 	bmake_free(p[i]);
547     }
548 
549     return mf.fp;
550 }
551 
552 static Boolean
553 boolValue(char *s)
554 {
555     switch(*s) {
556     case '0':
557     case 'N':
558     case 'n':
559     case 'F':
560     case 'f':
561 	return FALSE;
562     }
563     return TRUE;
564 }
565 
566 /*
567  * Initialization we need before reading makefiles.
568  */
569 void
570 meta_init(void)
571 {
572 #ifdef USE_FILEMON
573 	/* this allows makefiles to test if we have filemon support */
574 	Var_Set(".MAKE.PATH_FILEMON", filemon_path(), VAR_GLOBAL);
575 #endif
576 }
577 
578 
579 #define get_mode_bf(bf, token) \
580     if ((cp = strstr(make_mode, token))) \
581 	bf = boolValue(&cp[sizeof(token) - 1])
582 
583 /*
584  * Initialization we need after reading makefiles.
585  */
586 void
587 meta_mode_init(const char *make_mode)
588 {
589     static int once = 0;
590     char *cp;
591 
592     useMeta = TRUE;
593     useFilemon = TRUE;
594     writeMeta = TRUE;
595 
596     if (make_mode) {
597 	if (strstr(make_mode, "env"))
598 	    metaEnv = TRUE;
599 	if (strstr(make_mode, "verb"))
600 	    metaVerbose = TRUE;
601 	if (strstr(make_mode, "read"))
602 	    writeMeta = FALSE;
603 	if (strstr(make_mode, "nofilemon"))
604 	    useFilemon = FALSE;
605 	if (strstr(make_mode, "ignore-cmd"))
606 	    metaIgnoreCMDs = TRUE;
607 	if (useFilemon)
608 	    get_mode_bf(filemonMissing, "missing-filemon=");
609 	get_mode_bf(metaCurdirOk, "curdirok=");
610 	get_mode_bf(metaMissing, "missing-meta=");
611 	get_mode_bf(metaSilent, "silent=");
612     }
613     if (metaVerbose && !Var_Exists(MAKE_META_PREFIX, VAR_GLOBAL)) {
614 	/*
615 	 * The default value for MAKE_META_PREFIX
616 	 * prints the absolute path of the target.
617 	 * This works be cause :H will generate '.' if there is no /
618 	 * and :tA will resolve that to cwd.
619 	 */
620 	Var_Set(MAKE_META_PREFIX, "Building ${.TARGET:H:tA}/${.TARGET:T}", VAR_GLOBAL);
621     }
622     if (once)
623 	return;
624     once = 1;
625     memset(&Mybm, 0, sizeof(Mybm));
626     /*
627      * We consider ourselves master of all within ${.MAKE.META.BAILIWICK}
628      */
629     metaBailiwick = Lst_Init();
630     metaBailiwickStr = Var_Subst("${.MAKE.META.BAILIWICK:O:u:tA}",
631 	VAR_GLOBAL, VARE_WANTRES);
632     str2Lst_Append(metaBailiwick, metaBailiwickStr, NULL);
633     /*
634      * We ignore any paths that start with ${.MAKE.META.IGNORE_PATHS}
635      */
636     metaIgnorePaths = Lst_Init();
637     Var_Append(MAKE_META_IGNORE_PATHS,
638 	       "/dev /etc /proc /tmp /var/run /var/tmp ${TMPDIR}", VAR_GLOBAL);
639     metaIgnorePathsStr = Var_Subst("${" MAKE_META_IGNORE_PATHS ":O:u:tA}",
640 				   VAR_GLOBAL, VARE_WANTRES);
641     str2Lst_Append(metaIgnorePaths, metaIgnorePathsStr, NULL);
642 
643     /*
644      * We ignore any paths that match ${.MAKE.META.IGNORE_PATTERNS}
645      */
646     cp = NULL;
647     if (Var_Value(MAKE_META_IGNORE_PATTERNS, VAR_GLOBAL, &cp)) {
648 	metaIgnorePatterns = TRUE;
649 	bmake_free(cp);
650     }
651     cp = NULL;
652     if (Var_Value(MAKE_META_IGNORE_FILTER, VAR_GLOBAL, &cp)) {
653 	metaIgnoreFilter = TRUE;
654 	bmake_free(cp);
655     }
656 }
657 
658 /*
659  * In each case below we allow for job==NULL
660  */
661 void
662 meta_job_start(Job *job, GNode *gn)
663 {
664     BuildMon *pbm;
665 
666     if (job != NULL) {
667 	pbm = &job->bm;
668     } else {
669 	pbm = &Mybm;
670     }
671     pbm->mfp = meta_create(pbm, gn);
672 #ifdef USE_FILEMON_ONCE
673     /* compat mode we open the filemon dev once per command */
674     if (job == NULL)
675 	return;
676 #endif
677 #ifdef USE_FILEMON
678     if (pbm->mfp != NULL && useFilemon) {
679 	meta_open_filemon(pbm);
680     } else {
681 	pbm->mon_fd = -1;
682 	pbm->filemon = NULL;
683     }
684 #endif
685 }
686 
687 /*
688  * The child calls this before doing anything.
689  * It does not disturb our state.
690  */
691 void
692 meta_job_child(Job *job)
693 {
694 #ifdef USE_FILEMON
695     BuildMon *pbm;
696 
697     if (job != NULL) {
698 	pbm = &job->bm;
699     } else {
700 	pbm = &Mybm;
701     }
702     if (pbm->mfp != NULL) {
703 	close(fileno(pbm->mfp));
704 	if (useFilemon && pbm->filemon) {
705 	    pid_t pid;
706 
707 	    pid = getpid();
708 	    if (filemon_setpid_child(pbm->filemon, pid) == -1) {
709 		err(1, "Could not set filemon pid!");
710 	    }
711 	}
712     }
713 #endif
714 }
715 
716 void
717 meta_job_parent(Job *job, pid_t pid)
718 {
719 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
720     BuildMon *pbm;
721 
722     if (job != NULL) {
723 	pbm = &job->bm;
724     } else {
725 	pbm = &Mybm;
726     }
727     if (useFilemon && pbm->filemon) {
728 	filemon_setpid_parent(pbm->filemon, pid);
729     }
730 #endif
731 }
732 
733 int
734 meta_job_fd(Job *job)
735 {
736 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
737     BuildMon *pbm;
738 
739     if (job != NULL) {
740 	pbm = &job->bm;
741     } else {
742 	pbm = &Mybm;
743     }
744     if (useFilemon && pbm->filemon) {
745 	return filemon_readfd(pbm->filemon);
746     }
747 #endif
748     return -1;
749 }
750 
751 int
752 meta_job_event(Job *job)
753 {
754 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
755     BuildMon *pbm;
756 
757     if (job != NULL) {
758 	pbm = &job->bm;
759     } else {
760 	pbm = &Mybm;
761     }
762     if (useFilemon && pbm->filemon) {
763 	return filemon_process(pbm->filemon);
764     }
765 #endif
766     return 0;
767 }
768 
769 void
770 meta_job_error(Job *job, GNode *gn, int flags, int status)
771 {
772     char cwd[MAXPATHLEN];
773     BuildMon *pbm;
774 
775     if (job != NULL) {
776 	pbm = &job->bm;
777 	if (!gn)
778 	    gn = job->node;
779     } else {
780 	pbm = &Mybm;
781     }
782     if (pbm->mfp != NULL) {
783 	fprintf(pbm->mfp, "\n*** Error code %d%s\n",
784 		status,
785 		(flags & JOB_IGNERR) ?
786 		"(ignored)" : "");
787     }
788     if (gn) {
789 	Var_Set(".ERROR_TARGET", gn->path ? gn->path : gn->name, VAR_GLOBAL);
790     }
791     getcwd(cwd, sizeof(cwd));
792     Var_Set(".ERROR_CWD", cwd, VAR_GLOBAL);
793     if (pbm->meta_fname[0]) {
794 	Var_Set(".ERROR_META_FILE", pbm->meta_fname, VAR_GLOBAL);
795     }
796     meta_job_finish(job);
797 }
798 
799 void
800 meta_job_output(Job *job, char *cp, const char *nl)
801 {
802     BuildMon *pbm;
803 
804     if (job != NULL) {
805 	pbm = &job->bm;
806     } else {
807 	pbm = &Mybm;
808     }
809     if (pbm->mfp != NULL) {
810 	if (metaVerbose) {
811 	    static char *meta_prefix = NULL;
812 	    static int meta_prefix_len;
813 
814 	    if (!meta_prefix) {
815 		char *cp2;
816 
817 		meta_prefix = Var_Subst("${" MAKE_META_PREFIX "}",
818 					VAR_GLOBAL, VARE_WANTRES);
819 		if ((cp2 = strchr(meta_prefix, '$')))
820 		    meta_prefix_len = cp2 - meta_prefix;
821 		else
822 		    meta_prefix_len = strlen(meta_prefix);
823 	    }
824 	    if (strncmp(cp, meta_prefix, meta_prefix_len) == 0) {
825 		cp = strchr(cp+1, '\n');
826 		if (!cp++)
827 		    return;
828 	    }
829 	}
830 	fprintf(pbm->mfp, "%s%s", cp, nl);
831     }
832 }
833 
834 int
835 meta_cmd_finish(void *pbmp)
836 {
837     int error = 0;
838     BuildMon *pbm = pbmp;
839 #ifdef USE_FILEMON
840     int x;
841 #endif
842 
843     if (!pbm)
844 	pbm = &Mybm;
845 
846 #ifdef USE_FILEMON
847     if (pbm->filemon) {
848 	while (filemon_process(pbm->filemon) > 0)
849 	    continue;
850 	if (filemon_close(pbm->filemon) == -1)
851 	    error = errno;
852 	x = filemon_read(pbm->mfp, pbm->mon_fd);
853 	if (error == 0 && x != 0)
854 	    error = x;
855 	pbm->mon_fd = -1;
856 	pbm->filemon = NULL;
857     } else
858 #endif
859 	fprintf(pbm->mfp, "\n");	/* ensure end with newline */
860     return error;
861 }
862 
863 int
864 meta_job_finish(Job *job)
865 {
866     BuildMon *pbm;
867     int error = 0;
868     int x;
869 
870     if (job != NULL) {
871 	pbm = &job->bm;
872     } else {
873 	pbm = &Mybm;
874     }
875     if (pbm->mfp != NULL) {
876 	error = meta_cmd_finish(pbm);
877 	x = fclose(pbm->mfp);
878 	if (error == 0 && x != 0)
879 	    error = errno;
880 	pbm->mfp = NULL;
881 	pbm->meta_fname[0] = '\0';
882     }
883     return error;
884 }
885 
886 void
887 meta_finish(void)
888 {
889     if (metaBailiwick != NULL)
890 	Lst_Free(metaBailiwick);
891     free(metaBailiwickStr);
892     if (metaIgnorePaths != NULL)
893 	Lst_Free(metaIgnorePaths);
894     free(metaIgnorePathsStr);
895 }
896 
897 /*
898  * Fetch a full line from fp - growing bufp if needed
899  * Return length in bufp.
900  */
901 static int
902 fgetLine(char **bufp, size_t *szp, int o, FILE *fp)
903 {
904     char *buf = *bufp;
905     size_t bufsz = *szp;
906     struct stat fs;
907     int x;
908 
909     if (fgets(&buf[o], bufsz - o, fp) != NULL) {
910     check_newline:
911 	x = o + strlen(&buf[o]);
912 	if (buf[x - 1] == '\n')
913 	    return x;
914 	/*
915 	 * We need to grow the buffer.
916 	 * The meta file can give us a clue.
917 	 */
918 	if (fstat(fileno(fp), &fs) == 0) {
919 	    size_t newsz;
920 	    char *p;
921 
922 	    newsz = ROUNDUP((fs.st_size / 2), BUFSIZ);
923 	    if (newsz <= bufsz)
924 		newsz = ROUNDUP(fs.st_size, BUFSIZ);
925 	    if (newsz <= bufsz)
926 		return x;		/* truncated */
927 	    if (DEBUG(META))
928 		fprintf(debug_file, "growing buffer %zu -> %zu\n",
929 			bufsz, newsz);
930 	    p = bmake_realloc(buf, newsz);
931 	    if (p) {
932 		*bufp = buf = p;
933 		*szp = bufsz = newsz;
934 		/* fetch the rest */
935 		if (!fgets(&buf[x], bufsz - x, fp))
936 		    return x;		/* truncated! */
937 		goto check_newline;
938 	    }
939 	}
940     }
941     return 0;
942 }
943 
944 /* Lst_ForEach wants 1 to stop search */
945 static int
946 prefix_match(void *p, void *q)
947 {
948     const char *prefix = p;
949     const char *path = q;
950     size_t n = strlen(prefix);
951 
952     return strncmp(path, prefix, n) == 0;
953 }
954 
955 /* See if the path equals prefix or starts with "prefix/". */
956 static Boolean
957 path_match(const void *p, const void *q)
958 {
959     const char *path = p;
960     const char *prefix = q;
961     size_t n = strlen(prefix);
962 
963     if (strncmp(path, prefix, n) != 0)
964         return FALSE;
965     return path[n] == '\0' || path[n] == '/';
966 }
967 
968 static Boolean
969 string_match(const void *p, const void *q)
970 {
971     return strcmp(p, q) == 0;
972 }
973 
974 
975 static int
976 meta_ignore(GNode *gn, const char *p)
977 {
978     char fname[MAXPATHLEN];
979 
980     if (p == NULL)
981 	return TRUE;
982 
983     if (*p == '/') {
984 	cached_realpath(p, fname); /* clean it up */
985 	if (Lst_ForEach(metaIgnorePaths, prefix_match, fname)) {
986 #ifdef DEBUG_META_MODE
987 	    if (DEBUG(META))
988 		fprintf(debug_file, "meta_oodate: ignoring path: %s\n",
989 			p);
990 #endif
991 	    return TRUE;
992 	}
993     }
994 
995     if (metaIgnorePatterns) {
996 	const char *expr;
997 	char *pm;
998 
999 	Var_Set(".p.", p, gn);
1000 	expr = "${" MAKE_META_IGNORE_PATTERNS ":@m@${.p.:M$m}@}";
1001 	pm = Var_Subst(expr, gn, VARE_WANTRES);
1002 	if (*pm) {
1003 #ifdef DEBUG_META_MODE
1004 	    if (DEBUG(META))
1005 		fprintf(debug_file, "meta_oodate: ignoring pattern: %s\n",
1006 			p);
1007 #endif
1008 	    free(pm);
1009 	    return TRUE;
1010 	}
1011 	free(pm);
1012     }
1013 
1014     if (metaIgnoreFilter) {
1015 	char *fm;
1016 
1017 	/* skip if filter result is empty */
1018 	snprintf(fname, sizeof(fname),
1019 		 "${%s:L:${%s:ts:}}",
1020 		 p, MAKE_META_IGNORE_FILTER);
1021 	fm = Var_Subst(fname, gn, VARE_WANTRES);
1022 	if (*fm == '\0') {
1023 #ifdef DEBUG_META_MODE
1024 	    if (DEBUG(META))
1025 		fprintf(debug_file, "meta_oodate: ignoring filtered: %s\n",
1026 			p);
1027 #endif
1028 	    free(fm);
1029 	    return TRUE;
1030 	}
1031 	free(fm);
1032     }
1033     return FALSE;
1034 }
1035 
1036 /*
1037  * When running with 'meta' functionality, a target can be out-of-date
1038  * if any of the references in its meta data file is more recent.
1039  * We have to track the latestdir on a per-process basis.
1040  */
1041 #define LCWD_VNAME_FMT ".meta.%d.lcwd"
1042 #define LDIR_VNAME_FMT ".meta.%d.ldir"
1043 
1044 /*
1045  * It is possible that a .meta file is corrupted,
1046  * if we detect this we want to reproduce it.
1047  * Setting oodate TRUE will have that effect.
1048  */
1049 #define CHECK_VALID_META(p) if (!(p && *p)) { \
1050     warnx("%s: %d: malformed", fname, lineno); \
1051     oodate = TRUE; \
1052     continue; \
1053     }
1054 
1055 #define DEQUOTE(p) if (*p == '\'') {	\
1056     char *ep; \
1057     p++; \
1058     if ((ep = strchr(p, '\''))) \
1059 	*ep = '\0'; \
1060     }
1061 
1062 Boolean
1063 meta_oodate(GNode *gn, Boolean oodate)
1064 {
1065     static char *tmpdir = NULL;
1066     static char cwd[MAXPATHLEN];
1067     char lcwd_vname[64];
1068     char ldir_vname[64];
1069     char lcwd[MAXPATHLEN];
1070     char latestdir[MAXPATHLEN];
1071     char fname[MAXPATHLEN];
1072     char fname1[MAXPATHLEN];
1073     char fname2[MAXPATHLEN];
1074     char fname3[MAXPATHLEN];
1075     const char *dname;
1076     const char *tname;
1077     char *p;
1078     char *cp;
1079     char *link_src;
1080     char *move_target;
1081     static size_t cwdlen = 0;
1082     static size_t tmplen = 0;
1083     FILE *fp;
1084     Boolean needOODATE = FALSE;
1085     Lst missingFiles;
1086     char *pa[4];			/* >= possible uses */
1087     int i;
1088     int have_filemon = FALSE;
1089 
1090     if (oodate)
1091 	return oodate;		/* we're done */
1092 
1093     i = 0;
1094 
1095     dname = Var_Value(".OBJDIR", gn, &pa[i++]);
1096     tname = Var_Value(TARGET, gn, &pa[i++]);
1097 
1098     /* if this succeeds fname3 is realpath of dname */
1099     if (!meta_needed(gn, dname, tname, fname3, FALSE))
1100 	goto oodate_out;
1101     dname = fname3;
1102 
1103     missingFiles = Lst_Init();
1104 
1105     /*
1106      * We need to check if the target is out-of-date. This includes
1107      * checking if the expanded command has changed. This in turn
1108      * requires that all variables are set in the same way that they
1109      * would be if the target needs to be re-built.
1110      */
1111     Make_DoAllVar(gn);
1112 
1113     meta_name(gn, fname, sizeof(fname), dname, tname, dname);
1114 
1115 #ifdef DEBUG_META_MODE
1116     if (DEBUG(META))
1117 	fprintf(debug_file, "meta_oodate: %s\n", fname);
1118 #endif
1119 
1120     if ((fp = fopen(fname, "r")) != NULL) {
1121 	static char *buf = NULL;
1122 	static size_t bufsz;
1123 	int lineno = 0;
1124 	int lastpid = 0;
1125 	int pid;
1126 	int x;
1127 	LstNode ln;
1128 	struct make_stat mst;
1129 
1130 	if (!buf) {
1131 	    bufsz = 8 * BUFSIZ;
1132 	    buf = bmake_malloc(bufsz);
1133 	}
1134 
1135 	if (!cwdlen) {
1136 	    if (getcwd(cwd, sizeof(cwd)) == NULL)
1137 		err(1, "Could not get current working directory");
1138 	    cwdlen = strlen(cwd);
1139 	}
1140 	strlcpy(lcwd, cwd, sizeof(lcwd));
1141 	strlcpy(latestdir, cwd, sizeof(latestdir));
1142 
1143 	if (!tmpdir) {
1144 	    tmpdir = getTmpdir();
1145 	    tmplen = strlen(tmpdir);
1146 	}
1147 
1148 	/* we want to track all the .meta we read */
1149 	Var_Append(".MAKE.META.FILES", fname, VAR_GLOBAL);
1150 
1151 	ln = Lst_First(gn->commands);
1152 	while (!oodate && (x = fgetLine(&buf, &bufsz, 0, fp)) > 0) {
1153 	    lineno++;
1154 	    if (buf[x - 1] == '\n')
1155 		buf[x - 1] = '\0';
1156 	    else {
1157 		warnx("%s: %d: line truncated at %u", fname, lineno, x);
1158 		oodate = TRUE;
1159 		break;
1160 	    }
1161 	    link_src = NULL;
1162 	    move_target = NULL;
1163 	    /* Find the start of the build monitor section. */
1164 	    if (!have_filemon) {
1165 		if (strncmp(buf, "-- filemon", 10) == 0) {
1166 		    have_filemon = TRUE;
1167 		    continue;
1168 		}
1169 		if (strncmp(buf, "# buildmon", 10) == 0) {
1170 		    have_filemon = TRUE;
1171 		    continue;
1172 		}
1173 	    }
1174 
1175 	    /* Delimit the record type. */
1176 	    p = buf;
1177 #ifdef DEBUG_META_MODE
1178 	    if (DEBUG(META))
1179 		fprintf(debug_file, "%s: %d: %s\n", fname, lineno, buf);
1180 #endif
1181 	    strsep(&p, " ");
1182 	    if (have_filemon) {
1183 		/*
1184 		 * We are in the 'filemon' output section.
1185 		 * Each record from filemon follows the general form:
1186 		 *
1187 		 * <key> <pid> <data>
1188 		 *
1189 		 * Where:
1190 		 * <key> is a single letter, denoting the syscall.
1191 		 * <pid> is the process that made the syscall.
1192 		 * <data> is the arguments (of interest).
1193 		 */
1194 		switch(buf[0]) {
1195 		case '#':		/* comment */
1196 		case 'V':		/* version */
1197 		    break;
1198 		default:
1199 		    /*
1200 		     * We need to track pathnames per-process.
1201 		     *
1202 		     * Each process run by make, starts off in the 'CWD'
1203 		     * recorded in the .meta file, if it chdirs ('C')
1204 		     * elsewhere we need to track that - but only for
1205 		     * that process.  If it forks ('F'), we initialize
1206 		     * the child to have the same cwd as its parent.
1207 		     *
1208 		     * We also need to track the 'latestdir' of
1209 		     * interest.  This is usually the same as cwd, but
1210 		     * not if a process is reading directories.
1211 		     *
1212 		     * Each time we spot a different process ('pid')
1213 		     * we save the current value of 'latestdir' in a
1214 		     * variable qualified by 'lastpid', and
1215 		     * re-initialize 'latestdir' to any pre-saved
1216 		     * value for the current 'pid' and 'CWD' if none.
1217 		     */
1218 		    CHECK_VALID_META(p);
1219 		    pid = atoi(p);
1220 		    if (pid > 0 && pid != lastpid) {
1221 			const char *ldir;
1222 			char *tp;
1223 
1224 			if (lastpid > 0) {
1225 			    /* We need to remember these. */
1226 			    Var_Set(lcwd_vname, lcwd, VAR_GLOBAL);
1227 			    Var_Set(ldir_vname, latestdir, VAR_GLOBAL);
1228 			}
1229 			snprintf(lcwd_vname, sizeof(lcwd_vname), LCWD_VNAME_FMT, pid);
1230 			snprintf(ldir_vname, sizeof(ldir_vname), LDIR_VNAME_FMT, pid);
1231 			lastpid = pid;
1232 			ldir = Var_Value(ldir_vname, VAR_GLOBAL, &tp);
1233 			if (ldir) {
1234 			    strlcpy(latestdir, ldir, sizeof(latestdir));
1235 			    bmake_free(tp);
1236 			}
1237 			ldir = Var_Value(lcwd_vname, VAR_GLOBAL, &tp);
1238 			if (ldir) {
1239 			    strlcpy(lcwd, ldir, sizeof(lcwd));
1240 			    bmake_free(tp);
1241 			}
1242 		    }
1243 		    /* Skip past the pid. */
1244 		    if (strsep(&p, " ") == NULL)
1245 			continue;
1246 #ifdef DEBUG_META_MODE
1247 		    if (DEBUG(META))
1248 			    fprintf(debug_file, "%s: %d: %d: %c: cwd=%s lcwd=%s ldir=%s\n",
1249 				    fname, lineno,
1250 				    pid, buf[0], cwd, lcwd, latestdir);
1251 #endif
1252 		    break;
1253 		}
1254 
1255 		CHECK_VALID_META(p);
1256 
1257 		/* Process according to record type. */
1258 		switch (buf[0]) {
1259 		case 'X':		/* eXit */
1260 		    Var_Delete(lcwd_vname, VAR_GLOBAL);
1261 		    Var_Delete(ldir_vname, VAR_GLOBAL);
1262 		    lastpid = 0;	/* no need to save ldir_vname */
1263 		    break;
1264 
1265 		case 'F':		/* [v]Fork */
1266 		    {
1267 			char cldir[64];
1268 			int child;
1269 
1270 			child = atoi(p);
1271 			if (child > 0) {
1272 			    snprintf(cldir, sizeof(cldir), LCWD_VNAME_FMT, child);
1273 			    Var_Set(cldir, lcwd, VAR_GLOBAL);
1274 			    snprintf(cldir, sizeof(cldir), LDIR_VNAME_FMT, child);
1275 			    Var_Set(cldir, latestdir, VAR_GLOBAL);
1276 #ifdef DEBUG_META_MODE
1277 			    if (DEBUG(META))
1278 				    fprintf(debug_file, "%s: %d: %d: cwd=%s lcwd=%s ldir=%s\n",
1279 					    fname, lineno,
1280 					    child, cwd, lcwd, latestdir);
1281 #endif
1282 			}
1283 		    }
1284 		    break;
1285 
1286 		case 'C':		/* Chdir */
1287 		    /* Update lcwd and latest directory. */
1288 		    strlcpy(latestdir, p, sizeof(latestdir));
1289 		    strlcpy(lcwd, p, sizeof(lcwd));
1290 		    Var_Set(lcwd_vname, lcwd, VAR_GLOBAL);
1291 		    Var_Set(ldir_vname, lcwd, VAR_GLOBAL);
1292 #ifdef DEBUG_META_MODE
1293 		    if (DEBUG(META))
1294 			fprintf(debug_file, "%s: %d: cwd=%s ldir=%s\n", fname, lineno, cwd, lcwd);
1295 #endif
1296 		    break;
1297 
1298 		case 'M':		/* renaMe */
1299 		    /*
1300 		     * For 'M'oves we want to check
1301 		     * the src as for 'R'ead
1302 		     * and the target as for 'W'rite.
1303 		     */
1304 		    cp = p;		/* save this for a second */
1305 		    /* now get target */
1306 		    if (strsep(&p, " ") == NULL)
1307 			continue;
1308 		    CHECK_VALID_META(p);
1309 		    move_target = p;
1310 		    p = cp;
1311 		    /* 'L' and 'M' put single quotes around the args */
1312 		    DEQUOTE(p);
1313 		    DEQUOTE(move_target);
1314 		    /* FALLTHROUGH */
1315 		case 'D':		/* unlink */
1316 		    if (*p == '/' && !Lst_IsEmpty(missingFiles)) {
1317 			/* remove any missingFiles entries that match p */
1318 			ln = Lst_Find(missingFiles, path_match, p);
1319 			if (ln != NULL) {
1320 			    LstNode nln;
1321 			    char *tp;
1322 
1323 			    do {
1324 				nln = Lst_FindFrom(missingFiles,
1325 						   LstNode_Next(ln),
1326 						   path_match, p);
1327 				tp = LstNode_Datum(ln);
1328 				Lst_Remove(missingFiles, ln);
1329 				free(tp);
1330 			    } while ((ln = nln) != NULL);
1331 			}
1332 		    }
1333 		    if (buf[0] == 'M') {
1334 			/* the target of the mv is a file 'W'ritten */
1335 #ifdef DEBUG_META_MODE
1336 			if (DEBUG(META))
1337 			    fprintf(debug_file, "meta_oodate: M %s -> %s\n",
1338 				    p, move_target);
1339 #endif
1340 			p = move_target;
1341 			goto check_write;
1342 		    }
1343 		    break;
1344 		case 'L':		/* Link */
1345 		    /*
1346 		     * For 'L'inks check
1347 		     * the src as for 'R'ead
1348 		     * and the target as for 'W'rite.
1349 		     */
1350 		    link_src = p;
1351 		    /* now get target */
1352 		    if (strsep(&p, " ") == NULL)
1353 			continue;
1354 		    CHECK_VALID_META(p);
1355 		    /* 'L' and 'M' put single quotes around the args */
1356 		    DEQUOTE(p);
1357 		    DEQUOTE(link_src);
1358 #ifdef DEBUG_META_MODE
1359 		    if (DEBUG(META))
1360 			fprintf(debug_file, "meta_oodate: L %s -> %s\n",
1361 				link_src, p);
1362 #endif
1363 		    /* FALLTHROUGH */
1364 		case 'W':		/* Write */
1365 		check_write:
1366 		    /*
1367 		     * If a file we generated within our bailiwick
1368 		     * but outside of .OBJDIR is missing,
1369 		     * we need to do it again.
1370 		     */
1371 		    /* ignore non-absolute paths */
1372 		    if (*p != '/')
1373 			break;
1374 
1375 		    if (Lst_IsEmpty(metaBailiwick))
1376 			break;
1377 
1378 		    /* ignore cwd - normal dependencies handle those */
1379 		    if (strncmp(p, cwd, cwdlen) == 0)
1380 			break;
1381 
1382 		    if (!Lst_ForEach(metaBailiwick, prefix_match, p))
1383 			break;
1384 
1385 		    /* tmpdir might be within */
1386 		    if (tmplen > 0 && strncmp(p, tmpdir, tmplen) == 0)
1387 			break;
1388 
1389 		    /* ignore anything containing the string "tmp" */
1390 		    if ((strstr("tmp", p)))
1391 			break;
1392 
1393 		    if ((link_src != NULL && cached_lstat(p, &mst) < 0) ||
1394 			(link_src == NULL && cached_stat(p, &mst) < 0)) {
1395 			if (!meta_ignore(gn, p)) {
1396 			    if (Lst_Find(missingFiles, string_match, p) == NULL)
1397 				Lst_Append(missingFiles, bmake_strdup(p));
1398 			}
1399 		    }
1400 		    break;
1401 		check_link_src:
1402 		    p = link_src;
1403 		    link_src = NULL;
1404 #ifdef DEBUG_META_MODE
1405 		    if (DEBUG(META))
1406 			fprintf(debug_file, "meta_oodate: L src %s\n", p);
1407 #endif
1408 		    /* FALLTHROUGH */
1409 		case 'R':		/* Read */
1410 		case 'E':		/* Exec */
1411 		    /*
1412 		     * Check for runtime files that can't
1413 		     * be part of the dependencies because
1414 		     * they are _expected_ to change.
1415 		     */
1416 		    if (meta_ignore(gn, p))
1417 			break;
1418 
1419 		    /*
1420 		     * The rest of the record is the file name.
1421 		     * Check if it's not an absolute path.
1422 		     */
1423 		    {
1424 			char *sdirs[4];
1425 			char **sdp;
1426 			int sdx = 0;
1427 			int found = 0;
1428 
1429 			if (*p == '/') {
1430 			    sdirs[sdx++] = p; /* done */
1431 			} else {
1432 			    if (strcmp(".", p) == 0)
1433 				continue;  /* no point */
1434 
1435 			    /* Check vs latestdir */
1436 			    snprintf(fname1, sizeof(fname1), "%s/%s", latestdir, p);
1437 			    sdirs[sdx++] = fname1;
1438 
1439 			    if (strcmp(latestdir, lcwd) != 0) {
1440 				/* Check vs lcwd */
1441 				snprintf(fname2, sizeof(fname2), "%s/%s", lcwd, p);
1442 				sdirs[sdx++] = fname2;
1443 			    }
1444 			    if (strcmp(lcwd, cwd) != 0) {
1445 				/* Check vs cwd */
1446 				snprintf(fname3, sizeof(fname3), "%s/%s", cwd, p);
1447 				sdirs[sdx++] = fname3;
1448 			    }
1449 			}
1450 			sdirs[sdx++] = NULL;
1451 
1452 			for (sdp = sdirs; *sdp && !found; sdp++) {
1453 #ifdef DEBUG_META_MODE
1454 			    if (DEBUG(META))
1455 				fprintf(debug_file, "%s: %d: looking for: %s\n", fname, lineno, *sdp);
1456 #endif
1457 			    if (cached_stat(*sdp, &mst) == 0) {
1458 				found = 1;
1459 				p = *sdp;
1460 			    }
1461 			}
1462 			if (found) {
1463 #ifdef DEBUG_META_MODE
1464 			    if (DEBUG(META))
1465 				fprintf(debug_file, "%s: %d: found: %s\n", fname, lineno, p);
1466 #endif
1467 			    if (!S_ISDIR(mst.mst_mode) &&
1468 				mst.mst_mtime > gn->mtime) {
1469 				if (DEBUG(META))
1470 				    fprintf(debug_file, "%s: %d: file '%s' is newer than the target...\n", fname, lineno, p);
1471 				oodate = TRUE;
1472 			    } else if (S_ISDIR(mst.mst_mode)) {
1473 				/* Update the latest directory. */
1474 				cached_realpath(p, latestdir);
1475 			    }
1476 			} else if (errno == ENOENT && *p == '/' &&
1477 				   strncmp(p, cwd, cwdlen) != 0) {
1478 			    /*
1479 			     * A referenced file outside of CWD is missing.
1480 			     * We cannot catch every eventuality here...
1481 			     */
1482 			    if (Lst_Find(missingFiles, string_match, p) == NULL)
1483 				Lst_Append(missingFiles, bmake_strdup(p));
1484 			}
1485 		    }
1486 		    if (buf[0] == 'E') {
1487 			/* previous latestdir is no longer relevant */
1488 			strlcpy(latestdir, lcwd, sizeof(latestdir));
1489 		    }
1490 		    break;
1491 		default:
1492 		    break;
1493 		}
1494 		if (!oodate && buf[0] == 'L' && link_src != NULL)
1495 		    goto check_link_src;
1496 	    } else if (strcmp(buf, "CMD") == 0) {
1497 		/*
1498 		 * Compare the current command with the one in the
1499 		 * meta data file.
1500 		 */
1501 		if (ln == NULL) {
1502 		    if (DEBUG(META))
1503 			fprintf(debug_file, "%s: %d: there were more build commands in the meta data file than there are now...\n", fname, lineno);
1504 		    oodate = TRUE;
1505 		} else {
1506 		    char *cmd = LstNode_Datum(ln);
1507 		    Boolean hasOODATE = FALSE;
1508 
1509 		    if (strstr(cmd, "$?"))
1510 			hasOODATE = TRUE;
1511 		    else if ((cp = strstr(cmd, ".OODATE"))) {
1512 			/* check for $[{(].OODATE[:)}] */
1513 			if (cp > cmd + 2 && cp[-2] == '$')
1514 			    hasOODATE = TRUE;
1515 		    }
1516 		    if (hasOODATE) {
1517 			needOODATE = TRUE;
1518 			if (DEBUG(META))
1519 			    fprintf(debug_file, "%s: %d: cannot compare command using .OODATE\n", fname, lineno);
1520 		    }
1521 		    cmd = Var_Subst(cmd, gn, VARE_WANTRES|VARE_UNDEFERR);
1522 
1523 		    if ((cp = strchr(cmd, '\n'))) {
1524 			int n;
1525 
1526 			/*
1527 			 * This command contains newlines, we need to
1528 			 * fetch more from the .meta file before we
1529 			 * attempt a comparison.
1530 			 */
1531 			/* first put the newline back at buf[x - 1] */
1532 			buf[x - 1] = '\n';
1533 			do {
1534 			    /* now fetch the next line */
1535 			    if ((n = fgetLine(&buf, &bufsz, x, fp)) <= 0)
1536 				break;
1537 			    x = n;
1538 			    lineno++;
1539 			    if (buf[x - 1] != '\n') {
1540 				warnx("%s: %d: line truncated at %u", fname, lineno, x);
1541 				break;
1542 			    }
1543 			    cp = strchr(++cp, '\n');
1544 			} while (cp);
1545 			if (buf[x - 1] == '\n')
1546 			    buf[x - 1] = '\0';
1547 		    }
1548 		    if (p &&
1549 			!hasOODATE &&
1550 			!(gn->type & OP_NOMETA_CMP) &&
1551 			strcmp(p, cmd) != 0) {
1552 			if (DEBUG(META))
1553 			    fprintf(debug_file, "%s: %d: a build command has changed\n%s\nvs\n%s\n", fname, lineno, p, cmd);
1554 			if (!metaIgnoreCMDs)
1555 			    oodate = TRUE;
1556 		    }
1557 		    free(cmd);
1558 		    ln = LstNode_Next(ln);
1559 		}
1560 	    } else if (strcmp(buf, "CWD") == 0) {
1561 		/*
1562 		 * Check if there are extra commands now
1563 		 * that weren't in the meta data file.
1564 		 */
1565 		if (!oodate && ln != NULL) {
1566 		    if (DEBUG(META))
1567 			fprintf(debug_file, "%s: %d: there are extra build commands now that weren't in the meta data file\n", fname, lineno);
1568 		    oodate = TRUE;
1569 		}
1570 		CHECK_VALID_META(p);
1571 		if (strcmp(p, cwd) != 0) {
1572 		    if (DEBUG(META))
1573 			fprintf(debug_file, "%s: %d: the current working directory has changed from '%s' to '%s'\n", fname, lineno, p, curdir);
1574 		    oodate = TRUE;
1575 		}
1576 	    }
1577 	}
1578 
1579 	fclose(fp);
1580 	if (!Lst_IsEmpty(missingFiles)) {
1581 	    if (DEBUG(META))
1582 		fprintf(debug_file, "%s: missing files: %s...\n",
1583 			fname, (char *)LstNode_Datum(Lst_First(missingFiles)));
1584 	    oodate = TRUE;
1585 	}
1586 	if (!oodate && !have_filemon && filemonMissing) {
1587 	    if (DEBUG(META))
1588 		fprintf(debug_file, "%s: missing filemon data\n", fname);
1589 	    oodate = TRUE;
1590 	}
1591     } else {
1592 	if (writeMeta && (metaMissing || (gn->type & OP_META))) {
1593 	    cp = NULL;
1594 
1595 	    /* if target is in .CURDIR we do not need a meta file */
1596 	    if (gn->path && (cp = strrchr(gn->path, '/')) && cp > gn->path) {
1597 		if (strncmp(curdir, gn->path, (cp - gn->path)) != 0) {
1598 		    cp = NULL;		/* not in .CURDIR */
1599 		}
1600 	    }
1601 	    if (!cp) {
1602 		if (DEBUG(META))
1603 		    fprintf(debug_file, "%s: required but missing\n", fname);
1604 		oodate = TRUE;
1605 		needOODATE = TRUE;	/* assume the worst */
1606 	    }
1607 	}
1608     }
1609 
1610     Lst_Destroy(missingFiles, free);
1611 
1612     if (oodate && needOODATE) {
1613 	/*
1614 	 * Target uses .OODATE which is empty; or we wouldn't be here.
1615 	 * We have decided it is oodate, so .OODATE needs to be set.
1616 	 * All we can sanely do is set it to .ALLSRC.
1617 	 */
1618 	Var_Delete(OODATE, gn);
1619 	Var_Set(OODATE, Var_Value(ALLSRC, gn, &cp), gn);
1620 	bmake_free(cp);
1621     }
1622 
1623  oodate_out:
1624     for (i--; i >= 0; i--) {
1625 	bmake_free(pa[i]);
1626     }
1627     return oodate;
1628 }
1629 
1630 /* support for compat mode */
1631 
1632 static int childPipe[2];
1633 
1634 void
1635 meta_compat_start(void)
1636 {
1637 #ifdef USE_FILEMON_ONCE
1638     /*
1639      * We need to re-open filemon for each cmd.
1640      */
1641     BuildMon *pbm = &Mybm;
1642 
1643     if (pbm->mfp != NULL && useFilemon) {
1644 	meta_open_filemon(pbm);
1645     } else {
1646 	pbm->mon_fd = -1;
1647 	pbm->filemon = NULL;
1648     }
1649 #endif
1650     if (pipe(childPipe) < 0)
1651 	Punt("Cannot create pipe: %s", strerror(errno));
1652     /* Set close-on-exec flag for both */
1653     (void)fcntl(childPipe[0], F_SETFD, FD_CLOEXEC);
1654     (void)fcntl(childPipe[1], F_SETFD, FD_CLOEXEC);
1655 }
1656 
1657 void
1658 meta_compat_child(void)
1659 {
1660     meta_job_child(NULL);
1661     if (dup2(childPipe[1], 1) < 0 ||
1662 	dup2(1, 2) < 0) {
1663 	execError("dup2", "pipe");
1664 	_exit(1);
1665     }
1666 }
1667 
1668 void
1669 meta_compat_parent(pid_t child)
1670 {
1671     int outfd, metafd, maxfd, nfds;
1672     char buf[BUFSIZ+1];
1673     fd_set readfds;
1674 
1675     meta_job_parent(NULL, child);
1676     close(childPipe[1]);			/* child side */
1677     outfd = childPipe[0];
1678 #ifdef USE_FILEMON
1679     metafd = Mybm.filemon ? filemon_readfd(Mybm.filemon) : -1;
1680 #else
1681     metafd = -1;
1682 #endif
1683     maxfd = -1;
1684     if (outfd > maxfd)
1685 	    maxfd = outfd;
1686     if (metafd > maxfd)
1687 	    maxfd = metafd;
1688 
1689     while (outfd != -1 || metafd != -1) {
1690 	FD_ZERO(&readfds);
1691 	if (outfd != -1) {
1692 	    FD_SET(outfd, &readfds);
1693 	}
1694 	if (metafd != -1) {
1695 	    FD_SET(metafd, &readfds);
1696 	}
1697 	nfds = select(maxfd + 1, &readfds, NULL, NULL, NULL);
1698 	if (nfds == -1) {
1699 	    if (errno == EINTR)
1700 		continue;
1701 	    err(1, "select");
1702 	}
1703 
1704 	if (outfd != -1 && FD_ISSET(outfd, &readfds)) do {
1705 	    /* XXX this is not line-buffered */
1706 	    ssize_t nread = read(outfd, buf, sizeof(buf) - 1);
1707 	    if (nread == -1)
1708 		err(1, "read");
1709 	    if (nread == 0) {
1710 		close(outfd);
1711 		outfd = -1;
1712 		break;
1713 	    }
1714 	    fwrite(buf, 1, (size_t)nread, stdout);
1715 	    fflush(stdout);
1716 	    buf[nread] = '\0';
1717 	    meta_job_output(NULL, buf, "");
1718 	} while (0);
1719 	if (metafd != -1 && FD_ISSET(metafd, &readfds)) {
1720 	    if (meta_job_event(NULL) <= 0)
1721 		metafd = -1;
1722 	}
1723     }
1724 }
1725 
1726 #endif	/* USE_META */
1727