xref: /freebsd/contrib/bmake/meta.c (revision 6132212808e8dccedc9e5d85fea4390c2f38059a)
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 #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 Lst metaBailiwick;		/* our scope of control */
59 static char *metaBailiwickStr;		/* string storage for the list */
60 static Lst 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 Boolean comatMake;
88 extern char    **environ;
89 
90 #define	MAKE_META_PREFIX	".MAKE.META.PREFIX"
91 
92 #ifndef N2U
93 # define N2U(n, u)   (((n) + ((u) - 1)) / (u))
94 #endif
95 #ifndef ROUNDUP
96 # define ROUNDUP(n, u)   (N2U((n), (u)) * (u))
97 #endif
98 
99 #if !defined(HAVE_STRSEP)
100 # define strsep(s, d) stresep((s), (d), 0)
101 #endif
102 
103 /*
104  * Filemon is a kernel module which snoops certain syscalls.
105  *
106  * C chdir
107  * E exec
108  * F [v]fork
109  * L [sym]link
110  * M rename
111  * R read
112  * W write
113  * S stat
114  *
115  * See meta_oodate below - we mainly care about 'E' and 'R'.
116  *
117  * We can still use meta mode without filemon, but
118  * the benefits are more limited.
119  */
120 #ifdef USE_FILEMON
121 
122 /*
123  * Open the filemon device.
124  */
125 static void
126 meta_open_filemon(BuildMon *pbm)
127 {
128     int dupfd;
129 
130     pbm->mon_fd = -1;
131     pbm->filemon = NULL;
132     if (!useFilemon || !pbm->mfp)
133 	return;
134 
135     pbm->filemon = filemon_open();
136     if (pbm->filemon == NULL) {
137 	useFilemon = FALSE;
138 	warn("Could not open filemon %s", filemon_path());
139 	return;
140     }
141 
142     /*
143      * We use a file outside of '.'
144      * to avoid a FreeBSD kernel bug where unlink invalidates
145      * cwd causing getcwd to do a lot more work.
146      * We only care about the descriptor.
147      */
148     pbm->mon_fd = mkTempFile("filemon.XXXXXX", NULL);
149     if ((dupfd = dup(pbm->mon_fd)) == -1) {
150 	err(1, "Could not dup filemon output!");
151     }
152     (void)fcntl(dupfd, F_SETFD, FD_CLOEXEC);
153     if (filemon_setfd(pbm->filemon, dupfd) == -1) {
154 	err(1, "Could not set filemon file descriptor!");
155     }
156     /* we don't need these once we exec */
157     (void)fcntl(pbm->mon_fd, F_SETFD, FD_CLOEXEC);
158 }
159 
160 /*
161  * Read the build monitor output file and write records to the target's
162  * metadata file.
163  */
164 static int
165 filemon_read(FILE *mfp, int fd)
166 {
167     char buf[BUFSIZ];
168     int n;
169     int error;
170 
171     /* Check if we're not writing to a meta data file.*/
172     if (mfp == NULL) {
173 	if (fd >= 0)
174 	    close(fd);			/* not interested */
175 	return 0;
176     }
177     /* rewind */
178     if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
179 	error = errno;
180 	warn("Could not rewind filemon");
181 	fprintf(mfp, "\n");
182     } else {
183 	error = 0;
184 	fprintf(mfp, "\n-- filemon acquired metadata --\n");
185 
186 	while ((n = read(fd, buf, sizeof(buf))) > 0) {
187 	    if ((int)fwrite(buf, 1, 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 - (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) - (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 ${.MAKE}
317  * Bypassed if target is flagged .MAKE
318  */
319 static int
320 is_submake(void *cmdp, void *gnp)
321 {
322     static const char *p_make = NULL;
323     static int p_len;
324     char  *cmd = cmdp;
325     GNode *gn = gnp;
326     char *mp = NULL;
327     char *cp;
328     char *cp2;
329     int rc = 0;				/* keep looking */
330 
331     if (!p_make) {
332 	p_make = Var_Value(".MAKE", gn, &cp);
333 	p_len = strlen(p_make);
334     }
335     cp = strchr(cmd, '$');
336     if ((cp)) {
337 	mp = Var_Subst(cmd, gn, VARE_WANTRES);
338 	cmd = mp;
339     }
340     cp2 = strstr(cmd, p_make);
341     if ((cp2)) {
342 	switch (cp2[p_len]) {
343 	case '\0':
344 	case ' ':
345 	case '\t':
346 	case '\n':
347 	    rc = 1;
348 	    break;
349 	}
350 	if (cp2 > cmd && rc > 0) {
351 	    switch (cp2[-1]) {
352 	    case ' ':
353 	    case '\t':
354 	    case '\n':
355 		break;
356 	    default:
357 		rc = 0;			/* no match */
358 		break;
359 	    }
360 	}
361     }
362     free(mp);
363     return rc;
364 }
365 
366 typedef struct meta_file_s {
367     FILE *fp;
368     GNode *gn;
369 } meta_file_t;
370 
371 static int
372 printCMD(void *cmdp, void *mfpp)
373 {
374     meta_file_t *mfp = mfpp;
375     char *cmd = cmdp;
376     char *cmd_freeIt = NULL;
377 
378     if (strchr(cmd, '$')) {
379 	cmd = cmd_freeIt = Var_Subst(cmd, mfp->gn, VARE_WANTRES);
380     }
381     fprintf(mfp->fp, "CMD %s\n", cmd);
382     free(cmd_freeIt);
383     return 0;
384 }
385 
386 /*
387  * Certain node types never get a .meta file
388  */
389 #define SKIP_META_TYPE(_type) do { \
390     if ((gn->type & __CONCAT(OP_, _type))) {	\
391 	if (verbose) { \
392 	    fprintf(debug_file, "Skipping meta for %s: .%s\n", \
393 		    gn->name, __STRING(_type));		       \
394 	} \
395 	return FALSE; \
396     } \
397 } while (0)
398 
399 
400 /*
401  * Do we need/want a .meta file ?
402  */
403 static Boolean
404 meta_needed(GNode *gn, const char *dname,
405 	     char *objdir, int verbose)
406 {
407     struct make_stat mst;
408 
409     if (verbose)
410 	verbose = DEBUG(META);
411 
412     /* This may be a phony node which we don't want meta data for... */
413     /* Skip .meta for .BEGIN, .END, .ERROR etc as well. */
414     /* Or it may be explicitly flagged as .NOMETA */
415     SKIP_META_TYPE(NOMETA);
416     /* Unless it is explicitly flagged as .META */
417     if (!(gn->type & OP_META)) {
418 	SKIP_META_TYPE(PHONY);
419 	SKIP_META_TYPE(SPECIAL);
420 	SKIP_META_TYPE(MAKE);
421     }
422 
423     /* Check if there are no commands to execute. */
424     if (Lst_IsEmpty(gn->commands)) {
425 	if (verbose)
426 	    fprintf(debug_file, "Skipping meta for %s: no commands\n",
427 		    gn->name);
428 	return FALSE;
429     }
430     if ((gn->type & (OP_META|OP_SUBMAKE)) == OP_SUBMAKE) {
431 	/* OP_SUBMAKE is a bit too aggressive */
432 	if (Lst_ForEach(gn->commands, is_submake, gn)) {
433 	    if (DEBUG(META))
434 		fprintf(debug_file, "Skipping meta for %s: .SUBMAKE\n",
435 			gn->name);
436 	    return FALSE;
437 	}
438     }
439 
440     /* The object directory may not exist. Check it.. */
441     if (cached_stat(dname, &mst) != 0) {
442 	if (verbose)
443 	    fprintf(debug_file, "Skipping meta for %s: no .OBJDIR\n",
444 		    gn->name);
445 	return FALSE;
446     }
447 
448     /* make sure these are canonical */
449     if (cached_realpath(dname, objdir))
450 	dname = objdir;
451 
452     /* If we aren't in the object directory, don't create a meta file. */
453     if (!metaCurdirOk && strcmp(curdir, dname) == 0) {
454 	if (verbose)
455 	    fprintf(debug_file, "Skipping meta for %s: .OBJDIR == .CURDIR\n",
456 		    gn->name);
457 	return FALSE;
458     }
459     return TRUE;
460 }
461 
462 
463 static FILE *
464 meta_create(BuildMon *pbm, GNode *gn)
465 {
466     meta_file_t mf;
467     char buf[MAXPATHLEN];
468     char objdir[MAXPATHLEN];
469     char **ptr;
470     const char *dname;
471     const char *tname;
472     char *fname;
473     const char *cp;
474     char *p[5];				/* >= possible uses */
475     int i;
476 
477     mf.fp = NULL;
478     i = 0;
479 
480     dname = Var_Value(".OBJDIR", gn, &p[i++]);
481     tname = Var_Value(TARGET, gn, &p[i++]);
482 
483     /* if this succeeds objdir is realpath of dname */
484     if (!meta_needed(gn, dname, objdir, TRUE))
485 	goto out;
486     dname = objdir;
487 
488     if (metaVerbose) {
489 	char *mp;
490 
491 	/* Describe the target we are building */
492 	mp = Var_Subst("${" MAKE_META_PREFIX "}", gn, VARE_WANTRES);
493 	if (*mp)
494 	    fprintf(stdout, "%s\n", mp);
495 	free(mp);
496     }
497     /* Get the basename of the target */
498     if ((cp = strrchr(tname, '/')) == NULL) {
499 	cp = tname;
500     } else {
501 	cp++;
502     }
503 
504     fflush(stdout);
505 
506     if (!writeMeta)
507 	/* Don't create meta data. */
508 	goto out;
509 
510     fname = meta_name(pbm->meta_fname, sizeof(pbm->meta_fname),
511 		      dname, tname, objdir);
512 
513 #ifdef DEBUG_META_MODE
514     if (DEBUG(META))
515 	fprintf(debug_file, "meta_create: %s\n", fname);
516 #endif
517 
518     if ((mf.fp = fopen(fname, "w")) == NULL)
519 	err(1, "Could not open meta file '%s'", fname);
520 
521     fprintf(mf.fp, "# Meta data file %s\n", fname);
522 
523     mf.gn = gn;
524 
525     Lst_ForEach(gn->commands, printCMD, &mf);
526 
527     fprintf(mf.fp, "CWD %s\n", getcwd(buf, sizeof(buf)));
528     fprintf(mf.fp, "TARGET %s\n", tname);
529     cp = Var_Value(".OODATE", gn, &p[i++]);
530     if (cp && *cp) {
531 	    fprintf(mf.fp, "OODATE %s\n", cp);
532     }
533     if (metaEnv) {
534 	for (ptr = environ; *ptr != NULL; ptr++)
535 	    fprintf(mf.fp, "ENV %s\n", *ptr);
536     }
537 
538     fprintf(mf.fp, "-- command output --\n");
539     fflush(mf.fp);
540 
541     Var_Append(".MAKE.META.FILES", fname, VAR_GLOBAL);
542     Var_Append(".MAKE.META.CREATED", fname, VAR_GLOBAL);
543 
544     gn->type |= OP_META;		/* in case anyone wants to know */
545     if (metaSilent) {
546 	    gn->type |= OP_SILENT;
547     }
548  out:
549     for (i--; i >= 0; i--) {
550 	bmake_free(p[i]);
551     }
552 
553     return mf.fp;
554 }
555 
556 static Boolean
557 boolValue(char *s)
558 {
559     switch(*s) {
560     case '0':
561     case 'N':
562     case 'n':
563     case 'F':
564     case 'f':
565 	return FALSE;
566     }
567     return TRUE;
568 }
569 
570 /*
571  * Initialization we need before reading makefiles.
572  */
573 void
574 meta_init(void)
575 {
576 #ifdef USE_FILEMON
577 	/* this allows makefiles to test if we have filemon support */
578 	Var_Set(".MAKE.PATH_FILEMON", filemon_path(), VAR_GLOBAL);
579 #endif
580 }
581 
582 
583 #define get_mode_bf(bf, token) \
584     if ((cp = strstr(make_mode, token))) \
585 	bf = boolValue(&cp[sizeof(token) - 1])
586 
587 /*
588  * Initialization we need after reading makefiles.
589  */
590 void
591 meta_mode_init(const char *make_mode)
592 {
593     static int once = 0;
594     char *cp;
595 
596     useMeta = TRUE;
597     useFilemon = TRUE;
598     writeMeta = TRUE;
599 
600     if (make_mode) {
601 	if (strstr(make_mode, "env"))
602 	    metaEnv = TRUE;
603 	if (strstr(make_mode, "verb"))
604 	    metaVerbose = TRUE;
605 	if (strstr(make_mode, "read"))
606 	    writeMeta = FALSE;
607 	if (strstr(make_mode, "nofilemon"))
608 	    useFilemon = FALSE;
609 	if (strstr(make_mode, "ignore-cmd"))
610 	    metaIgnoreCMDs = TRUE;
611 	if (useFilemon)
612 	    get_mode_bf(filemonMissing, "missing-filemon=");
613 	get_mode_bf(metaCurdirOk, "curdirok=");
614 	get_mode_bf(metaMissing, "missing-meta=");
615 	get_mode_bf(metaSilent, "silent=");
616     }
617     if (metaVerbose && !Var_Exists(MAKE_META_PREFIX, VAR_GLOBAL)) {
618 	/*
619 	 * The default value for MAKE_META_PREFIX
620 	 * prints the absolute path of the target.
621 	 * This works be cause :H will generate '.' if there is no /
622 	 * and :tA will resolve that to cwd.
623 	 */
624 	Var_Set(MAKE_META_PREFIX, "Building ${.TARGET:H:tA}/${.TARGET:T}", VAR_GLOBAL);
625     }
626     if (once)
627 	return;
628     once = 1;
629     memset(&Mybm, 0, sizeof(Mybm));
630     /*
631      * We consider ourselves master of all within ${.MAKE.META.BAILIWICK}
632      */
633     metaBailiwick = Lst_Init();
634     metaBailiwickStr = Var_Subst("${.MAKE.META.BAILIWICK:O:u:tA}",
635 	VAR_GLOBAL, VARE_WANTRES);
636     str2Lst_Append(metaBailiwick, metaBailiwickStr, NULL);
637     /*
638      * We ignore any paths that start with ${.MAKE.META.IGNORE_PATHS}
639      */
640     metaIgnorePaths = Lst_Init();
641     Var_Append(MAKE_META_IGNORE_PATHS,
642 	       "/dev /etc /proc /tmp /var/run /var/tmp ${TMPDIR}", VAR_GLOBAL);
643     metaIgnorePathsStr = Var_Subst("${" MAKE_META_IGNORE_PATHS ":O:u:tA}",
644 				   VAR_GLOBAL, VARE_WANTRES);
645     str2Lst_Append(metaIgnorePaths, metaIgnorePathsStr, NULL);
646 
647     /*
648      * We ignore any paths that match ${.MAKE.META.IGNORE_PATTERNS}
649      */
650     cp = NULL;
651     if (Var_Value(MAKE_META_IGNORE_PATTERNS, VAR_GLOBAL, &cp)) {
652 	metaIgnorePatterns = TRUE;
653 	bmake_free(cp);
654     }
655     cp = NULL;
656     if (Var_Value(MAKE_META_IGNORE_FILTER, VAR_GLOBAL, &cp)) {
657 	metaIgnoreFilter = TRUE;
658 	bmake_free(cp);
659     }
660 }
661 
662 /*
663  * In each case below we allow for job==NULL
664  */
665 void
666 meta_job_start(Job *job, GNode *gn)
667 {
668     BuildMon *pbm;
669 
670     if (job != NULL) {
671 	pbm = &job->bm;
672     } else {
673 	pbm = &Mybm;
674     }
675     pbm->mfp = meta_create(pbm, gn);
676 #ifdef USE_FILEMON_ONCE
677     /* compat mode we open the filemon dev once per command */
678     if (job == NULL)
679 	return;
680 #endif
681 #ifdef USE_FILEMON
682     if (pbm->mfp != NULL && useFilemon) {
683 	meta_open_filemon(pbm);
684     } else {
685 	pbm->mon_fd = -1;
686 	pbm->filemon = NULL;
687     }
688 #endif
689 }
690 
691 /*
692  * The child calls this before doing anything.
693  * It does not disturb our state.
694  */
695 void
696 meta_job_child(Job *job)
697 {
698 #ifdef USE_FILEMON
699     BuildMon *pbm;
700 
701     if (job != NULL) {
702 	pbm = &job->bm;
703     } else {
704 	pbm = &Mybm;
705     }
706     if (pbm->mfp != NULL) {
707 	close(fileno(pbm->mfp));
708 	if (useFilemon && pbm->filemon) {
709 	    pid_t pid;
710 
711 	    pid = getpid();
712 	    if (filemon_setpid_child(pbm->filemon, pid) == -1) {
713 		err(1, "Could not set filemon pid!");
714 	    }
715 	}
716     }
717 #endif
718 }
719 
720 void
721 meta_job_parent(Job *job, pid_t pid)
722 {
723 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
724     BuildMon *pbm;
725 
726     if (job != NULL) {
727 	pbm = &job->bm;
728     } else {
729 	pbm = &Mybm;
730     }
731     if (useFilemon && pbm->filemon) {
732 	filemon_setpid_parent(pbm->filemon, pid);
733     }
734 #endif
735 }
736 
737 int
738 meta_job_fd(Job *job)
739 {
740 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
741     BuildMon *pbm;
742 
743     if (job != NULL) {
744 	pbm = &job->bm;
745     } else {
746 	pbm = &Mybm;
747     }
748     if (useFilemon && pbm->filemon) {
749 	return filemon_readfd(pbm->filemon);
750     }
751 #endif
752     return -1;
753 }
754 
755 int
756 meta_job_event(Job *job)
757 {
758 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
759     BuildMon *pbm;
760 
761     if (job != NULL) {
762 	pbm = &job->bm;
763     } else {
764 	pbm = &Mybm;
765     }
766     if (useFilemon && pbm->filemon) {
767 	return filemon_process(pbm->filemon);
768     }
769 #endif
770     return 0;
771 }
772 
773 void
774 meta_job_error(Job *job, GNode *gn, int flags, int status)
775 {
776     char cwd[MAXPATHLEN];
777     BuildMon *pbm;
778 
779     if (job != NULL) {
780 	pbm = &job->bm;
781 	if (!gn)
782 	    gn = job->node;
783     } else {
784 	pbm = &Mybm;
785     }
786     if (pbm->mfp != NULL) {
787 	fprintf(pbm->mfp, "\n*** Error code %d%s\n",
788 		status,
789 		(flags & JOB_IGNERR) ?
790 		"(ignored)" : "");
791     }
792     if (gn) {
793 	Var_Set(".ERROR_TARGET", gn->path ? gn->path : gn->name, VAR_GLOBAL);
794     }
795     getcwd(cwd, sizeof(cwd));
796     Var_Set(".ERROR_CWD", cwd, VAR_GLOBAL);
797     if (pbm->meta_fname[0]) {
798 	Var_Set(".ERROR_META_FILE", pbm->meta_fname, VAR_GLOBAL);
799     }
800     meta_job_finish(job);
801 }
802 
803 void
804 meta_job_output(Job *job, char *cp, const char *nl)
805 {
806     BuildMon *pbm;
807 
808     if (job != NULL) {
809 	pbm = &job->bm;
810     } else {
811 	pbm = &Mybm;
812     }
813     if (pbm->mfp != NULL) {
814 	if (metaVerbose) {
815 	    static char *meta_prefix = NULL;
816 	    static int meta_prefix_len;
817 
818 	    if (!meta_prefix) {
819 		char *cp2;
820 
821 		meta_prefix = Var_Subst("${" MAKE_META_PREFIX "}",
822 					VAR_GLOBAL, VARE_WANTRES);
823 		if ((cp2 = strchr(meta_prefix, '$')))
824 		    meta_prefix_len = cp2 - meta_prefix;
825 		else
826 		    meta_prefix_len = strlen(meta_prefix);
827 	    }
828 	    if (strncmp(cp, meta_prefix, meta_prefix_len) == 0) {
829 		cp = strchr(cp+1, '\n');
830 		if (!cp++)
831 		    return;
832 	    }
833 	}
834 	fprintf(pbm->mfp, "%s%s", cp, nl);
835     }
836 }
837 
838 int
839 meta_cmd_finish(void *pbmp)
840 {
841     int error = 0;
842     BuildMon *pbm = pbmp;
843 #ifdef USE_FILEMON
844     int x;
845 #endif
846 
847     if (!pbm)
848 	pbm = &Mybm;
849 
850 #ifdef USE_FILEMON
851     if (pbm->filemon) {
852 	while (filemon_process(pbm->filemon) > 0)
853 	    continue;
854 	if (filemon_close(pbm->filemon) == -1)
855 	    error = errno;
856 	x = filemon_read(pbm->mfp, pbm->mon_fd);
857 	if (error == 0 && x != 0)
858 	    error = x;
859 	pbm->mon_fd = -1;
860 	pbm->filemon = NULL;
861     } else
862 #endif
863 	fprintf(pbm->mfp, "\n");	/* ensure end with newline */
864     return error;
865 }
866 
867 int
868 meta_job_finish(Job *job)
869 {
870     BuildMon *pbm;
871     int error = 0;
872     int x;
873 
874     if (job != NULL) {
875 	pbm = &job->bm;
876     } else {
877 	pbm = &Mybm;
878     }
879     if (pbm->mfp != NULL) {
880 	error = meta_cmd_finish(pbm);
881 	x = fclose(pbm->mfp);
882 	if (error == 0 && x != 0)
883 	    error = errno;
884 	pbm->mfp = NULL;
885 	pbm->meta_fname[0] = '\0';
886     }
887     return error;
888 }
889 
890 void
891 meta_finish(void)
892 {
893     if (metaBailiwick != NULL)
894 	Lst_Free(metaBailiwick);
895     free(metaBailiwickStr);
896     if (metaIgnorePaths != NULL)
897 	Lst_Free(metaIgnorePaths);
898     free(metaIgnorePathsStr);
899 }
900 
901 /*
902  * Fetch a full line from fp - growing bufp if needed
903  * Return length in bufp.
904  */
905 static int
906 fgetLine(char **bufp, size_t *szp, int o, FILE *fp)
907 {
908     char *buf = *bufp;
909     size_t bufsz = *szp;
910     struct stat fs;
911     int x;
912 
913     if (fgets(&buf[o], bufsz - o, fp) != NULL) {
914     check_newline:
915 	x = o + strlen(&buf[o]);
916 	if (buf[x - 1] == '\n')
917 	    return x;
918 	/*
919 	 * We need to grow the buffer.
920 	 * The meta file can give us a clue.
921 	 */
922 	if (fstat(fileno(fp), &fs) == 0) {
923 	    size_t newsz;
924 	    char *p;
925 
926 	    newsz = ROUNDUP((fs.st_size / 2), BUFSIZ);
927 	    if (newsz <= bufsz)
928 		newsz = ROUNDUP(fs.st_size, BUFSIZ);
929 	    if (newsz <= bufsz)
930 		return x;		/* truncated */
931 	    if (DEBUG(META))
932 		fprintf(debug_file, "growing buffer %u -> %u\n",
933 			(unsigned)bufsz, (unsigned)newsz);
934 	    p = bmake_realloc(buf, newsz);
935 	    if (p) {
936 		*bufp = buf = p;
937 		*szp = bufsz = newsz;
938 		/* fetch the rest */
939 		if (!fgets(&buf[x], bufsz - x, fp))
940 		    return x;		/* truncated! */
941 		goto check_newline;
942 	    }
943 	}
944     }
945     return 0;
946 }
947 
948 /* Lst_ForEach wants 1 to stop search */
949 static int
950 prefix_match(void *p, void *q)
951 {
952     const char *prefix = p;
953     const char *path = q;
954     size_t n = strlen(prefix);
955 
956     return strncmp(path, prefix, n) == 0;
957 }
958 
959 /* See if the path equals prefix or starts with "prefix/". */
960 static Boolean
961 path_match(const void *p, const void *q)
962 {
963     const char *path = p;
964     const char *prefix = q;
965     size_t n = strlen(prefix);
966 
967     if (strncmp(path, prefix, n) != 0)
968         return FALSE;
969     return path[n] == '\0' || path[n] == '/';
970 }
971 
972 static Boolean
973 string_match(const void *p, const void *q)
974 {
975     return strcmp(p, q) == 0;
976 }
977 
978 
979 static int
980 meta_ignore(GNode *gn, const char *p)
981 {
982     char fname[MAXPATHLEN];
983 
984     if (p == NULL)
985 	return TRUE;
986 
987     if (*p == '/') {
988 	cached_realpath(p, fname); /* clean it up */
989 	if (Lst_ForEach(metaIgnorePaths, prefix_match, fname)) {
990 #ifdef DEBUG_META_MODE
991 	    if (DEBUG(META))
992 		fprintf(debug_file, "meta_oodate: ignoring path: %s\n",
993 			p);
994 #endif
995 	    return TRUE;
996 	}
997     }
998 
999     if (metaIgnorePatterns) {
1000 	const char *expr;
1001 	char *pm;
1002 
1003 	Var_Set(".p.", p, gn);
1004 	expr = "${" MAKE_META_IGNORE_PATTERNS ":@m@${.p.:M$m}@}";
1005 	pm = Var_Subst(expr, gn, VARE_WANTRES);
1006 	if (*pm) {
1007 #ifdef DEBUG_META_MODE
1008 	    if (DEBUG(META))
1009 		fprintf(debug_file, "meta_oodate: ignoring pattern: %s\n",
1010 			p);
1011 #endif
1012 	    free(pm);
1013 	    return TRUE;
1014 	}
1015 	free(pm);
1016     }
1017 
1018     if (metaIgnoreFilter) {
1019 	char *fm;
1020 
1021 	/* skip if filter result is empty */
1022 	snprintf(fname, sizeof(fname),
1023 		 "${%s:L:${%s:ts:}}",
1024 		 p, MAKE_META_IGNORE_FILTER);
1025 	fm = Var_Subst(fname, gn, VARE_WANTRES);
1026 	if (*fm == '\0') {
1027 #ifdef DEBUG_META_MODE
1028 	    if (DEBUG(META))
1029 		fprintf(debug_file, "meta_oodate: ignoring filtered: %s\n",
1030 			p);
1031 #endif
1032 	    free(fm);
1033 	    return TRUE;
1034 	}
1035 	free(fm);
1036     }
1037     return FALSE;
1038 }
1039 
1040 /*
1041  * When running with 'meta' functionality, a target can be out-of-date
1042  * if any of the references in its meta data file is more recent.
1043  * We have to track the latestdir on a per-process basis.
1044  */
1045 #define LCWD_VNAME_FMT ".meta.%d.lcwd"
1046 #define LDIR_VNAME_FMT ".meta.%d.ldir"
1047 
1048 /*
1049  * It is possible that a .meta file is corrupted,
1050  * if we detect this we want to reproduce it.
1051  * Setting oodate TRUE will have that effect.
1052  */
1053 #define CHECK_VALID_META(p) if (!(p && *p)) { \
1054     warnx("%s: %d: malformed", fname, lineno); \
1055     oodate = TRUE; \
1056     continue; \
1057     }
1058 
1059 #define DEQUOTE(p) if (*p == '\'') {	\
1060     char *ep; \
1061     p++; \
1062     if ((ep = strchr(p, '\''))) \
1063 	*ep = '\0'; \
1064     }
1065 
1066 Boolean
1067 meta_oodate(GNode *gn, Boolean oodate)
1068 {
1069     static char *tmpdir = NULL;
1070     static char cwd[MAXPATHLEN];
1071     char lcwd_vname[64];
1072     char ldir_vname[64];
1073     char lcwd[MAXPATHLEN];
1074     char latestdir[MAXPATHLEN];
1075     char fname[MAXPATHLEN];
1076     char fname1[MAXPATHLEN];
1077     char fname2[MAXPATHLEN];
1078     char fname3[MAXPATHLEN];
1079     const char *dname;
1080     const char *tname;
1081     char *p;
1082     char *cp;
1083     char *link_src;
1084     char *move_target;
1085     static size_t cwdlen = 0;
1086     static size_t tmplen = 0;
1087     FILE *fp;
1088     Boolean needOODATE = FALSE;
1089     Lst missingFiles;
1090     char *pa[4];			/* >= possible uses */
1091     int i;
1092     int have_filemon = FALSE;
1093 
1094     if (oodate)
1095 	return oodate;		/* we're done */
1096 
1097     i = 0;
1098 
1099     dname = Var_Value(".OBJDIR", gn, &pa[i++]);
1100     tname = Var_Value(TARGET, gn, &pa[i++]);
1101 
1102     /* if this succeeds fname3 is realpath of dname */
1103     if (!meta_needed(gn, dname, fname3, FALSE))
1104 	goto oodate_out;
1105     dname = fname3;
1106 
1107     missingFiles = Lst_Init();
1108 
1109     /*
1110      * We need to check if the target is out-of-date. This includes
1111      * checking if the expanded command has changed. This in turn
1112      * requires that all variables are set in the same way that they
1113      * would be if the target needs to be re-built.
1114      */
1115     Make_DoAllVar(gn);
1116 
1117     meta_name(fname, sizeof(fname), dname, tname, dname);
1118 
1119 #ifdef DEBUG_META_MODE
1120     if (DEBUG(META))
1121 	fprintf(debug_file, "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 	LstNode ln;
1132 	struct make_stat mst;
1133 
1134 	if (!buf) {
1135 	    bufsz = 8 * BUFSIZ;
1136 	    buf = bmake_malloc(bufsz);
1137 	}
1138 
1139 	if (!cwdlen) {
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) {
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 	ln = Lst_First(gn->commands);
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 	    if (DEBUG(META))
1183 		fprintf(debug_file, "%s: %d: %s\n", fname, lineno, buf);
1184 #endif
1185 	    strsep(&p, " ");
1186 	    if (have_filemon) {
1187 		/*
1188 		 * We are in the 'filemon' output section.
1189 		 * Each record from filemon follows the general form:
1190 		 *
1191 		 * <key> <pid> <data>
1192 		 *
1193 		 * Where:
1194 		 * <key> is a single letter, denoting the syscall.
1195 		 * <pid> is the process that made the syscall.
1196 		 * <data> is the arguments (of interest).
1197 		 */
1198 		switch(buf[0]) {
1199 		case '#':		/* comment */
1200 		case 'V':		/* version */
1201 		    break;
1202 		default:
1203 		    /*
1204 		     * We need to track pathnames per-process.
1205 		     *
1206 		     * Each process run by make, starts off in the 'CWD'
1207 		     * recorded in the .meta file, if it chdirs ('C')
1208 		     * elsewhere we need to track that - but only for
1209 		     * that process.  If it forks ('F'), we initialize
1210 		     * the child to have the same cwd as its parent.
1211 		     *
1212 		     * We also need to track the 'latestdir' of
1213 		     * interest.  This is usually the same as cwd, but
1214 		     * not if a process is reading directories.
1215 		     *
1216 		     * Each time we spot a different process ('pid')
1217 		     * we save the current value of 'latestdir' in a
1218 		     * variable qualified by 'lastpid', and
1219 		     * re-initialize 'latestdir' to any pre-saved
1220 		     * value for the current 'pid' and 'CWD' if none.
1221 		     */
1222 		    CHECK_VALID_META(p);
1223 		    pid = atoi(p);
1224 		    if (pid > 0 && pid != lastpid) {
1225 			const char *ldir;
1226 			char *tp;
1227 
1228 			if (lastpid > 0) {
1229 			    /* We need to remember these. */
1230 			    Var_Set(lcwd_vname, lcwd, VAR_GLOBAL);
1231 			    Var_Set(ldir_vname, latestdir, VAR_GLOBAL);
1232 			}
1233 			snprintf(lcwd_vname, sizeof(lcwd_vname), LCWD_VNAME_FMT, pid);
1234 			snprintf(ldir_vname, sizeof(ldir_vname), LDIR_VNAME_FMT, pid);
1235 			lastpid = pid;
1236 			ldir = Var_Value(ldir_vname, VAR_GLOBAL, &tp);
1237 			if (ldir) {
1238 			    strlcpy(latestdir, ldir, sizeof(latestdir));
1239 			    bmake_free(tp);
1240 			}
1241 			ldir = Var_Value(lcwd_vname, VAR_GLOBAL, &tp);
1242 			if (ldir) {
1243 			    strlcpy(lcwd, ldir, sizeof(lcwd));
1244 			    bmake_free(tp);
1245 			}
1246 		    }
1247 		    /* Skip past the pid. */
1248 		    if (strsep(&p, " ") == NULL)
1249 			continue;
1250 #ifdef DEBUG_META_MODE
1251 		    if (DEBUG(META))
1252 			    fprintf(debug_file, "%s: %d: %d: %c: cwd=%s lcwd=%s ldir=%s\n",
1253 				    fname, lineno,
1254 				    pid, buf[0], cwd, lcwd, latestdir);
1255 #endif
1256 		    break;
1257 		}
1258 
1259 		CHECK_VALID_META(p);
1260 
1261 		/* Process according to record type. */
1262 		switch (buf[0]) {
1263 		case 'X':		/* eXit */
1264 		    Var_Delete(lcwd_vname, VAR_GLOBAL);
1265 		    Var_Delete(ldir_vname, VAR_GLOBAL);
1266 		    lastpid = 0;	/* no need to save ldir_vname */
1267 		    break;
1268 
1269 		case 'F':		/* [v]Fork */
1270 		    {
1271 			char cldir[64];
1272 			int child;
1273 
1274 			child = atoi(p);
1275 			if (child > 0) {
1276 			    snprintf(cldir, sizeof(cldir), LCWD_VNAME_FMT, child);
1277 			    Var_Set(cldir, lcwd, VAR_GLOBAL);
1278 			    snprintf(cldir, sizeof(cldir), LDIR_VNAME_FMT, child);
1279 			    Var_Set(cldir, latestdir, VAR_GLOBAL);
1280 #ifdef DEBUG_META_MODE
1281 			    if (DEBUG(META))
1282 				    fprintf(debug_file, "%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 		    if (DEBUG(META))
1298 			fprintf(debug_file, "%s: %d: cwd=%s ldir=%s\n", 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 == '/' && !Lst_IsEmpty(missingFiles)) {
1321 			/* remove any missingFiles entries that match p */
1322 			ln = Lst_Find(missingFiles, path_match, p);
1323 			if (ln != NULL) {
1324 			    LstNode nln;
1325 			    char *tp;
1326 
1327 			    do {
1328 				nln = Lst_FindFrom(missingFiles,
1329 						   LstNode_Next(ln),
1330 						   path_match, p);
1331 				tp = LstNode_Datum(ln);
1332 				Lst_Remove(missingFiles, ln);
1333 				free(tp);
1334 			    } while ((ln = nln) != NULL);
1335 			}
1336 		    }
1337 		    if (buf[0] == 'M') {
1338 			/* the target of the mv is a file 'W'ritten */
1339 #ifdef DEBUG_META_MODE
1340 			if (DEBUG(META))
1341 			    fprintf(debug_file, "meta_oodate: M %s -> %s\n",
1342 				    p, move_target);
1343 #endif
1344 			p = move_target;
1345 			goto check_write;
1346 		    }
1347 		    break;
1348 		case 'L':		/* Link */
1349 		    /*
1350 		     * For 'L'inks check
1351 		     * the src as for 'R'ead
1352 		     * and the target as for 'W'rite.
1353 		     */
1354 		    link_src = p;
1355 		    /* now get target */
1356 		    if (strsep(&p, " ") == NULL)
1357 			continue;
1358 		    CHECK_VALID_META(p);
1359 		    /* 'L' and 'M' put single quotes around the args */
1360 		    DEQUOTE(p);
1361 		    DEQUOTE(link_src);
1362 #ifdef DEBUG_META_MODE
1363 		    if (DEBUG(META))
1364 			fprintf(debug_file, "meta_oodate: L %s -> %s\n",
1365 				link_src, p);
1366 #endif
1367 		    /* FALLTHROUGH */
1368 		case 'W':		/* Write */
1369 		check_write:
1370 		    /*
1371 		     * If a file we generated within our bailiwick
1372 		     * but outside of .OBJDIR is missing,
1373 		     * we need to do it again.
1374 		     */
1375 		    /* ignore non-absolute paths */
1376 		    if (*p != '/')
1377 			break;
1378 
1379 		    if (Lst_IsEmpty(metaBailiwick))
1380 			break;
1381 
1382 		    /* ignore cwd - normal dependencies handle those */
1383 		    if (strncmp(p, cwd, cwdlen) == 0)
1384 			break;
1385 
1386 		    if (!Lst_ForEach(metaBailiwick, prefix_match, p))
1387 			break;
1388 
1389 		    /* tmpdir might be within */
1390 		    if (tmplen > 0 && strncmp(p, tmpdir, tmplen) == 0)
1391 			break;
1392 
1393 		    /* ignore anything containing the string "tmp" */
1394 		    if ((strstr("tmp", p)))
1395 			break;
1396 
1397 		    if ((link_src != NULL && cached_lstat(p, &mst) < 0) ||
1398 			(link_src == NULL && cached_stat(p, &mst) < 0)) {
1399 			if (!meta_ignore(gn, p)) {
1400 			    if (Lst_Find(missingFiles, string_match, p) == NULL)
1401 				Lst_Append(missingFiles, bmake_strdup(p));
1402 			}
1403 		    }
1404 		    break;
1405 		check_link_src:
1406 		    p = link_src;
1407 		    link_src = NULL;
1408 #ifdef DEBUG_META_MODE
1409 		    if (DEBUG(META))
1410 			fprintf(debug_file, "meta_oodate: L src %s\n", p);
1411 #endif
1412 		    /* FALLTHROUGH */
1413 		case 'R':		/* Read */
1414 		case 'E':		/* Exec */
1415 		    /*
1416 		     * Check for runtime files that can't
1417 		     * be part of the dependencies because
1418 		     * they are _expected_ to change.
1419 		     */
1420 		    if (meta_ignore(gn, p))
1421 			break;
1422 
1423 		    /*
1424 		     * The rest of the record is the file name.
1425 		     * Check if it's not an absolute path.
1426 		     */
1427 		    {
1428 			char *sdirs[4];
1429 			char **sdp;
1430 			int sdx = 0;
1431 			int found = 0;
1432 
1433 			if (*p == '/') {
1434 			    sdirs[sdx++] = p; /* done */
1435 			} else {
1436 			    if (strcmp(".", p) == 0)
1437 				continue;  /* no point */
1438 
1439 			    /* Check vs latestdir */
1440 			    snprintf(fname1, sizeof(fname1), "%s/%s", latestdir, p);
1441 			    sdirs[sdx++] = fname1;
1442 
1443 			    if (strcmp(latestdir, lcwd) != 0) {
1444 				/* Check vs lcwd */
1445 				snprintf(fname2, sizeof(fname2), "%s/%s", lcwd, p);
1446 				sdirs[sdx++] = fname2;
1447 			    }
1448 			    if (strcmp(lcwd, cwd) != 0) {
1449 				/* Check vs cwd */
1450 				snprintf(fname3, sizeof(fname3), "%s/%s", cwd, p);
1451 				sdirs[sdx++] = fname3;
1452 			    }
1453 			}
1454 			sdirs[sdx++] = NULL;
1455 
1456 			for (sdp = sdirs; *sdp && !found; sdp++) {
1457 #ifdef DEBUG_META_MODE
1458 			    if (DEBUG(META))
1459 				fprintf(debug_file, "%s: %d: looking for: %s\n", fname, lineno, *sdp);
1460 #endif
1461 			    if (cached_stat(*sdp, &mst) == 0) {
1462 				found = 1;
1463 				p = *sdp;
1464 			    }
1465 			}
1466 			if (found) {
1467 #ifdef DEBUG_META_MODE
1468 			    if (DEBUG(META))
1469 				fprintf(debug_file, "%s: %d: found: %s\n", fname, lineno, p);
1470 #endif
1471 			    if (!S_ISDIR(mst.mst_mode) &&
1472 				mst.mst_mtime > gn->mtime) {
1473 				if (DEBUG(META))
1474 				    fprintf(debug_file, "%s: %d: file '%s' is newer than the target...\n", fname, lineno, p);
1475 				oodate = TRUE;
1476 			    } else if (S_ISDIR(mst.mst_mode)) {
1477 				/* Update the latest directory. */
1478 				cached_realpath(p, latestdir);
1479 			    }
1480 			} else if (errno == ENOENT && *p == '/' &&
1481 				   strncmp(p, cwd, cwdlen) != 0) {
1482 			    /*
1483 			     * A referenced file outside of CWD is missing.
1484 			     * We cannot catch every eventuality here...
1485 			     */
1486 			    if (Lst_Find(missingFiles, string_match, p) == NULL)
1487 				Lst_Append(missingFiles, bmake_strdup(p));
1488 			}
1489 		    }
1490 		    if (buf[0] == 'E') {
1491 			/* previous latestdir is no longer relevant */
1492 			strlcpy(latestdir, lcwd, sizeof(latestdir));
1493 		    }
1494 		    break;
1495 		default:
1496 		    break;
1497 		}
1498 		if (!oodate && buf[0] == 'L' && link_src != NULL)
1499 		    goto check_link_src;
1500 	    } else if (strcmp(buf, "CMD") == 0) {
1501 		/*
1502 		 * Compare the current command with the one in the
1503 		 * meta data file.
1504 		 */
1505 		if (ln == NULL) {
1506 		    if (DEBUG(META))
1507 			fprintf(debug_file, "%s: %d: there were more build commands in the meta data file than there are now...\n", fname, lineno);
1508 		    oodate = TRUE;
1509 		} else {
1510 		    char *cmd = LstNode_Datum(ln);
1511 		    Boolean hasOODATE = FALSE;
1512 
1513 		    if (strstr(cmd, "$?"))
1514 			hasOODATE = TRUE;
1515 		    else if ((cp = strstr(cmd, ".OODATE"))) {
1516 			/* check for $[{(].OODATE[:)}] */
1517 			if (cp > cmd + 2 && cp[-2] == '$')
1518 			    hasOODATE = TRUE;
1519 		    }
1520 		    if (hasOODATE) {
1521 			needOODATE = TRUE;
1522 			if (DEBUG(META))
1523 			    fprintf(debug_file, "%s: %d: cannot compare command using .OODATE\n", fname, lineno);
1524 		    }
1525 		    cmd = Var_Subst(cmd, gn, VARE_WANTRES|VARE_UNDEFERR);
1526 
1527 		    if ((cp = strchr(cmd, '\n'))) {
1528 			int n;
1529 
1530 			/*
1531 			 * This command contains newlines, we need to
1532 			 * fetch more from the .meta file before we
1533 			 * attempt a comparison.
1534 			 */
1535 			/* first put the newline back at buf[x - 1] */
1536 			buf[x - 1] = '\n';
1537 			do {
1538 			    /* now fetch the next line */
1539 			    if ((n = fgetLine(&buf, &bufsz, x, fp)) <= 0)
1540 				break;
1541 			    x = n;
1542 			    lineno++;
1543 			    if (buf[x - 1] != '\n') {
1544 				warnx("%s: %d: line truncated at %u", fname, lineno, x);
1545 				break;
1546 			    }
1547 			    cp = strchr(++cp, '\n');
1548 			} while (cp);
1549 			if (buf[x - 1] == '\n')
1550 			    buf[x - 1] = '\0';
1551 		    }
1552 		    if (p &&
1553 			!hasOODATE &&
1554 			!(gn->type & OP_NOMETA_CMP) &&
1555 			strcmp(p, cmd) != 0) {
1556 			if (DEBUG(META))
1557 			    fprintf(debug_file, "%s: %d: a build command has changed\n%s\nvs\n%s\n", fname, lineno, p, cmd);
1558 			if (!metaIgnoreCMDs)
1559 			    oodate = TRUE;
1560 		    }
1561 		    free(cmd);
1562 		    ln = LstNode_Next(ln);
1563 		}
1564 	    } else if (strcmp(buf, "CWD") == 0) {
1565 		/*
1566 		 * Check if there are extra commands now
1567 		 * that weren't in the meta data file.
1568 		 */
1569 		if (!oodate && ln != NULL) {
1570 		    if (DEBUG(META))
1571 			fprintf(debug_file, "%s: %d: there are extra build commands now that weren't in the meta data file\n", fname, lineno);
1572 		    oodate = TRUE;
1573 		}
1574 		CHECK_VALID_META(p);
1575 		if (strcmp(p, cwd) != 0) {
1576 		    if (DEBUG(META))
1577 			fprintf(debug_file, "%s: %d: the current working directory has changed from '%s' to '%s'\n", fname, lineno, p, curdir);
1578 		    oodate = TRUE;
1579 		}
1580 	    }
1581 	}
1582 
1583 	fclose(fp);
1584 	if (!Lst_IsEmpty(missingFiles)) {
1585 	    if (DEBUG(META))
1586 		fprintf(debug_file, "%s: missing files: %s...\n",
1587 			fname, (char *)LstNode_Datum(Lst_First(missingFiles)));
1588 	    oodate = TRUE;
1589 	}
1590 	if (!oodate && !have_filemon && filemonMissing) {
1591 	    if (DEBUG(META))
1592 		fprintf(debug_file, "%s: missing filemon data\n", fname);
1593 	    oodate = TRUE;
1594 	}
1595     } else {
1596 	if (writeMeta && (metaMissing || (gn->type & OP_META))) {
1597 	    cp = NULL;
1598 
1599 	    /* if target is in .CURDIR we do not need a meta file */
1600 	    if (gn->path && (cp = strrchr(gn->path, '/')) && cp > gn->path) {
1601 		if (strncmp(curdir, gn->path, (cp - gn->path)) != 0) {
1602 		    cp = NULL;		/* not in .CURDIR */
1603 		}
1604 	    }
1605 	    if (!cp) {
1606 		if (DEBUG(META))
1607 		    fprintf(debug_file, "%s: required but missing\n", fname);
1608 		oodate = TRUE;
1609 		needOODATE = TRUE;	/* assume the worst */
1610 	    }
1611 	}
1612     }
1613 
1614     Lst_Destroy(missingFiles, free);
1615 
1616     if (oodate && needOODATE) {
1617 	/*
1618 	 * Target uses .OODATE which is empty; or we wouldn't be here.
1619 	 * We have decided it is oodate, so .OODATE needs to be set.
1620 	 * All we can sanely do is set it to .ALLSRC.
1621 	 */
1622 	Var_Delete(OODATE, gn);
1623 	Var_Set(OODATE, Var_Value(ALLSRC, gn, &cp), gn);
1624 	bmake_free(cp);
1625     }
1626 
1627  oodate_out:
1628     for (i--; i >= 0; i--) {
1629 	bmake_free(pa[i]);
1630     }
1631     return oodate;
1632 }
1633 
1634 /* support for compat mode */
1635 
1636 static int childPipe[2];
1637 
1638 void
1639 meta_compat_start(void)
1640 {
1641 #ifdef USE_FILEMON_ONCE
1642     /*
1643      * We need to re-open filemon for each cmd.
1644      */
1645     BuildMon *pbm = &Mybm;
1646 
1647     if (pbm->mfp != NULL && useFilemon) {
1648 	meta_open_filemon(pbm);
1649     } else {
1650 	pbm->mon_fd = -1;
1651 	pbm->filemon = NULL;
1652     }
1653 #endif
1654     if (pipe(childPipe) < 0)
1655 	Punt("Cannot create pipe: %s", strerror(errno));
1656     /* Set close-on-exec flag for both */
1657     (void)fcntl(childPipe[0], F_SETFD, FD_CLOEXEC);
1658     (void)fcntl(childPipe[1], F_SETFD, FD_CLOEXEC);
1659 }
1660 
1661 void
1662 meta_compat_child(void)
1663 {
1664     meta_job_child(NULL);
1665     if (dup2(childPipe[1], 1) < 0 ||
1666 	dup2(1, 2) < 0) {
1667 	execError("dup2", "pipe");
1668 	_exit(1);
1669     }
1670 }
1671 
1672 void
1673 meta_compat_parent(pid_t child)
1674 {
1675     int outfd, metafd, maxfd, nfds;
1676     char buf[BUFSIZ+1];
1677     fd_set readfds;
1678 
1679     meta_job_parent(NULL, child);
1680     close(childPipe[1]);			/* child side */
1681     outfd = childPipe[0];
1682 #ifdef USE_FILEMON
1683     metafd = Mybm.filemon ? filemon_readfd(Mybm.filemon) : -1;
1684 #else
1685     metafd = -1;
1686 #endif
1687     maxfd = -1;
1688     if (outfd > maxfd)
1689 	    maxfd = outfd;
1690     if (metafd > maxfd)
1691 	    maxfd = metafd;
1692 
1693     while (outfd != -1 || metafd != -1) {
1694 	FD_ZERO(&readfds);
1695 	if (outfd != -1) {
1696 	    FD_SET(outfd, &readfds);
1697 	}
1698 	if (metafd != -1) {
1699 	    FD_SET(metafd, &readfds);
1700 	}
1701 	nfds = select(maxfd + 1, &readfds, NULL, NULL, NULL);
1702 	if (nfds == -1) {
1703 	    if (errno == EINTR)
1704 		continue;
1705 	    err(1, "select");
1706 	}
1707 
1708 	if (outfd != -1 && FD_ISSET(outfd, &readfds)) do {
1709 	    /* XXX this is not line-buffered */
1710 	    ssize_t nread = read(outfd, buf, sizeof(buf) - 1);
1711 	    if (nread == -1)
1712 		err(1, "read");
1713 	    if (nread == 0) {
1714 		close(outfd);
1715 		outfd = -1;
1716 		break;
1717 	    }
1718 	    fwrite(buf, 1, (size_t)nread, stdout);
1719 	    fflush(stdout);
1720 	    buf[nread] = '\0';
1721 	    meta_job_output(NULL, buf, "");
1722 	} while (0);
1723 	if (metafd != -1 && FD_ISSET(metafd, &readfds)) {
1724 	    if (meta_job_event(NULL) <= 0)
1725 		metafd = -1;
1726 	}
1727     }
1728 }
1729 
1730 #endif	/* USE_META */
1731