xref: /freebsd/contrib/bmake/meta.c (revision d9a42747950146bf03cda7f6e25d219253f8a57a)
1 /*      $NetBSD: meta.c,v 1.201 2022/09/28 16:34:47 sjg Exp $ */
2 
3 /*
4  * Implement 'meta' mode.
5  * Adapted from John Birrell's patches to FreeBSD make.
6  * --sjg
7  */
8 /*
9  * Copyright (c) 2009-2016, Juniper Networks, Inc.
10  * Portions Copyright (c) 2009, John Birrell.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 #if defined(USE_META)
34 
35 #ifdef HAVE_CONFIG_H
36 # include "config.h"
37 #endif
38 #include <sys/stat.h>
39 #ifdef HAVE_LIBGEN_H
40 #include <libgen.h>
41 #elif !defined(HAVE_DIRNAME)
42 char * dirname(char *);
43 #endif
44 #include <errno.h>
45 #if !defined(HAVE_CONFIG_H) || defined(HAVE_ERR_H)
46 #include <err.h>
47 #endif
48 
49 #include "make.h"
50 #include "dir.h"
51 #include "job.h"
52 
53 #ifdef USE_FILEMON
54 #include "filemon/filemon.h"
55 #endif
56 
57 static BuildMon Mybm;			/* for compat */
58 static StringList metaBailiwick = LST_INIT; /* our scope of control */
59 static char *metaBailiwickStr;		/* string storage for the list */
60 static StringList metaIgnorePaths = LST_INIT; /* 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 #ifndef MAKE_META_CMP_FILTER
73 #define MAKE_META_CMP_FILTER ".MAKE.META.CMP_FILTER"
74 #endif
75 
76 bool useMeta = false;
77 static bool useFilemon = false;
78 static bool writeMeta = false;
79 static bool metaMissing = false;	/* oodate if missing */
80 static bool filemonMissing = false;	/* oodate if missing */
81 static bool metaEnv = false;		/* don't save env unless asked */
82 static bool metaVerbose = false;
83 static bool metaIgnoreCMDs = false;	/* ignore CMDs in .meta files */
84 static bool metaIgnorePatterns = false; /* do we need to do pattern matches */
85 static bool metaIgnoreFilter = false;	/* do we have more complex filtering? */
86 static bool metaCmpFilter = false;	/* do we have CMP_FILTER ? */
87 static bool metaCurdirOk = false;	/* write .meta in .CURDIR Ok? */
88 static bool metaSilent = false;		/* if we have a .meta be SILENT */
89 
90 extern bool forceJobs;
91 extern char    **environ;
92 
93 #define MAKE_META_PREFIX	".MAKE.META.PREFIX"
94 
95 #ifndef N2U
96 # define N2U(n, u)   (((n) + ((u) - 1)) / (u))
97 #endif
98 #ifndef ROUNDUP
99 # define ROUNDUP(n, u)   (N2U((n), (u)) * (u))
100 #endif
101 
102 #if !defined(HAVE_STRSEP)
103 # define strsep(s, d) stresep((s), (d), '\0')
104 #endif
105 #if !defined(HAVE_STRESEP)
106 char * stresep(char **, const char *, int);
107 #endif
108 
109 /*
110  * Filemon is a kernel module which snoops certain syscalls.
111  *
112  * C chdir
113  * E exec
114  * F [v]fork
115  * L [sym]link
116  * M rename
117  * R read
118  * W write
119  * S stat
120  *
121  * See meta_oodate below - we mainly care about 'E' and 'R'.
122  *
123  * We can still use meta mode without filemon, but
124  * the benefits are more limited.
125  */
126 #ifdef USE_FILEMON
127 
128 /*
129  * Open the filemon device.
130  */
131 static void
132 meta_open_filemon(BuildMon *pbm)
133 {
134     int dupfd;
135 
136     pbm->mon_fd = -1;
137     pbm->filemon = NULL;
138     if (!useFilemon || pbm->mfp == NULL)
139 	return;
140 
141     pbm->filemon = filemon_open();
142     if (pbm->filemon == NULL) {
143 	useFilemon = false;
144 	warn("Could not open filemon %s", filemon_path());
145 	return;
146     }
147 
148     /*
149      * We use a file outside of '.'
150      * to avoid a FreeBSD kernel bug where unlink invalidates
151      * cwd causing getcwd to do a lot more work.
152      * We only care about the descriptor.
153      */
154     if (!opts.compatMake)
155 	pbm->mon_fd = Job_TempFile("filemon.XXXXXX", NULL, 0);
156     else
157 	pbm->mon_fd = mkTempFile("filemon.XXXXXX", NULL, 0);
158     if ((dupfd = dup(pbm->mon_fd)) == -1) {
159 	Punt("Could not dup filemon output: %s", strerror(errno));
160     }
161     (void)fcntl(dupfd, F_SETFD, FD_CLOEXEC);
162     if (filemon_setfd(pbm->filemon, dupfd) == -1) {
163 	Punt("Could not set filemon file descriptor: %s", strerror(errno));
164     }
165     /* we don't need these once we exec */
166     (void)fcntl(pbm->mon_fd, F_SETFD, FD_CLOEXEC);
167 }
168 
169 /*
170  * Read the build monitor output file and write records to the target's
171  * metadata file.
172  */
173 static int
174 filemon_read(FILE *mfp, int fd)
175 {
176     char buf[BUFSIZ];
177     int error;
178 
179     /* Check if we're not writing to a meta data file.*/
180     if (mfp == NULL) {
181 	if (fd >= 0)
182 	    close(fd);			/* not interested */
183 	return 0;
184     }
185     /* rewind */
186     if (lseek(fd, (off_t)0, SEEK_SET) < 0) {
187 	error = errno;
188 	warn("Could not rewind filemon");
189 	fprintf(mfp, "\n");
190     } else {
191 	ssize_t n;
192 
193 	error = 0;
194 	fprintf(mfp, "\n-- filemon acquired metadata --\n");
195 
196 	while ((n = read(fd, buf, sizeof buf)) > 0) {
197 	    if ((ssize_t)fwrite(buf, 1, (size_t)n, mfp) < n)
198 		error = EIO;
199 	}
200     }
201     if (fflush(mfp) != 0)
202 	Punt("Cannot write filemon data to meta file: %s",
203 	    strerror(errno));
204     if (close(fd) < 0)
205 	error = errno;
206     return error;
207 }
208 #endif
209 
210 /*
211  * when realpath() fails,
212  * we use this, to clean up ./ and ../
213  */
214 static void
215 eat_dots(char *buf)
216 {
217     char *p;
218 
219     while ((p = strstr(buf, "/./")) != NULL)
220 	memmove(p, p + 2, strlen(p + 2) + 1);
221 
222     while ((p = strstr(buf, "/../")) != NULL) {
223 	char *p2 = p + 3;
224 	if (p > buf) {
225 	    do {
226 		p--;
227 	    } while (p > buf && *p != '/');
228 	}
229 	if (*p == '/')
230 	    memmove(p, p2, strlen(p2) + 1);
231 	else
232 	    return;		/* can't happen? */
233     }
234 }
235 
236 static char *
237 meta_name(char *mname, size_t mnamelen,
238 	  const char *dname,
239 	  const char *tname,
240 	  const char *cwd)
241 {
242     char buf[MAXPATHLEN];
243     char *rp, *cp;
244     const char *tname_base;
245     char *tp;
246     char *dtp;
247     size_t ldname;
248 
249     /*
250      * Weed out relative paths from the target file name.
251      * We have to be careful though since if target is a
252      * symlink, the result will be unstable.
253      * So we use realpath() just to get the dirname, and leave the
254      * basename as given to us.
255      */
256     if ((tname_base = strrchr(tname, '/')) != NULL) {
257 	if (cached_realpath(tname, buf) != NULL) {
258 	    if ((rp = strrchr(buf, '/')) != NULL) {
259 		rp++;
260 		tname_base++;
261 		if (strcmp(tname_base, rp) != 0)
262 		    strlcpy(rp, tname_base, sizeof buf - (size_t)(rp - buf));
263 	    }
264 	    tname = buf;
265 	} else {
266 	    /*
267 	     * We likely have a directory which is about to be made.
268 	     * We pretend realpath() succeeded, to have a chance
269 	     * of generating the same meta file name that we will
270 	     * next time through.
271 	     */
272 	    if (tname[0] == '/') {
273 		strlcpy(buf, tname, sizeof buf);
274 	    } else {
275 		snprintf(buf, sizeof buf, "%s/%s", cwd, tname);
276 	    }
277 	    eat_dots(buf);
278 	    tname = buf;
279 	}
280     }
281     /* on some systems dirname may modify its arg */
282     tp = bmake_strdup(tname);
283     dtp = dirname(tp);
284     if (strcmp(dname, dtp) == 0) {
285 	if (snprintf(mname, mnamelen, "%s.meta", tname) >= (int)mnamelen)
286 	    mname[mnamelen - 1] = '\0';
287     } else {
288 	int x;
289 
290 	ldname = strlen(dname);
291 	if (strncmp(dname, dtp, ldname) == 0 && dtp[ldname] == '/')
292 	    x = snprintf(mname, mnamelen, "%s/%s.meta", dname, &tname[ldname+1]);
293 	else
294 	    x = snprintf(mname, mnamelen, "%s/%s.meta", dname, tname);
295 	if (x >= (int)mnamelen)
296 	    mname[mnamelen - 1] = '\0';
297 	/*
298 	 * Replace path separators in the file name after the
299 	 * current object directory path.
300 	 */
301 	cp = mname + strlen(dname) + 1;
302 
303 	while (*cp != '\0') {
304 	    if (*cp == '/')
305 		*cp = '_';
306 	    cp++;
307 	}
308     }
309     free(tp);
310     return mname;
311 }
312 
313 /*
314  * Return true if running ${.MAKE}
315  * Bypassed if target is flagged .MAKE
316  */
317 static bool
318 is_submake(const char *cmd, GNode *gn)
319 {
320     static const char *p_make = NULL;
321     static size_t p_len;
322     char *mp = NULL;
323     const char *cp2;
324     bool rc = false;
325 
326     if (p_make == NULL) {
327 	p_make = Var_Value(gn, ".MAKE").str;
328 	p_len = strlen(p_make);
329     }
330     if (strchr(cmd, '$') != NULL) {
331 	(void)Var_Subst(cmd, gn, VARE_WANTRES, &mp);
332 	/* TODO: handle errors */
333 	cmd = mp;
334     }
335     cp2 = strstr(cmd, p_make);
336     if (cp2 != NULL) {
337 	switch (cp2[p_len]) {
338 	case '\0':
339 	case ' ':
340 	case '\t':
341 	case '\n':
342 	    rc = true;
343 	    break;
344 	}
345 	if (cp2 > cmd && rc) {
346 	    switch (cp2[-1]) {
347 	    case ' ':
348 	    case '\t':
349 	    case '\n':
350 		break;
351 	    default:
352 		rc = false;		/* no match */
353 		break;
354 	    }
355 	}
356     }
357     free(mp);
358     return rc;
359 }
360 
361 static bool
362 any_is_submake(GNode *gn)
363 {
364     StringListNode *ln;
365 
366     for (ln = gn->commands.first; ln != NULL; ln = ln->next)
367 	if (is_submake(ln->datum, gn))
368 	    return true;
369     return false;
370 }
371 
372 static void
373 printCMD(const char *ucmd, FILE *fp, GNode *gn)
374 {
375     FStr xcmd = FStr_InitRefer(ucmd);
376 
377     Var_Expand(&xcmd, gn, VARE_WANTRES);
378     fprintf(fp, "CMD %s\n", xcmd.str);
379     FStr_Done(&xcmd);
380 }
381 
382 static void
383 printCMDs(GNode *gn, FILE *fp)
384 {
385     StringListNode *ln;
386 
387     for (ln = gn->commands.first; ln != NULL; ln = ln->next)
388 	printCMD(ln->datum, fp, gn);
389 }
390 
391 /*
392  * Certain node types never get a .meta file
393  */
394 #define SKIP_META_TYPE(flag, str) do { \
395     if ((gn->type & (flag))) { \
396 	if (verbose) \
397 	    debug_printf("Skipping meta for %s: .%s\n", gn->name, str); \
398 	return false; \
399     } \
400 } while (false)
401 
402 
403 /*
404  * Do we need/want a .meta file ?
405  */
406 static bool
407 meta_needed(GNode *gn, const char *dname,
408 	    char *objdir_realpath, bool verbose)
409 {
410     struct cached_stat cst;
411 
412     if (verbose)
413 	verbose = DEBUG(META);
414 
415     /* This may be a phony node which we don't want meta data for... */
416     /* Skip .meta for .BEGIN, .END, .ERROR etc as well. */
417     /* Or it may be explicitly flagged as .NOMETA */
418     SKIP_META_TYPE(OP_NOMETA, "NOMETA");
419     /* Unless it is explicitly flagged as .META */
420     if (!(gn->type & OP_META)) {
421 	SKIP_META_TYPE(OP_PHONY, "PHONY");
422 	SKIP_META_TYPE(OP_SPECIAL, "SPECIAL");
423 	SKIP_META_TYPE(OP_MAKE, "MAKE");
424     }
425 
426     /* Check if there are no commands to execute. */
427     if (Lst_IsEmpty(&gn->commands)) {
428 	if (verbose)
429 	    debug_printf("Skipping meta for %s: no commands\n", gn->name);
430 	return false;
431     }
432     if ((gn->type & (OP_META|OP_SUBMAKE)) == OP_SUBMAKE) {
433 	/* OP_SUBMAKE is a bit too aggressive */
434 	if (any_is_submake(gn)) {
435 	    DEBUG1(META, "Skipping meta for %s: .SUBMAKE\n", gn->name);
436 	    return false;
437 	}
438     }
439 
440     /* The object directory may not exist. Check it.. */
441     if (cached_stat(dname, &cst) != 0) {
442 	if (verbose)
443 	    debug_printf("Skipping meta for %s: no .OBJDIR\n", gn->name);
444 	return false;
445     }
446 
447     /* make sure these are canonical */
448     if (cached_realpath(dname, objdir_realpath) != NULL)
449 	dname = objdir_realpath;
450 
451     /* If we aren't in the object directory, don't create a meta file. */
452     if (!metaCurdirOk && strcmp(curdir, dname) == 0) {
453 	if (verbose)
454 	    debug_printf("Skipping meta for %s: .OBJDIR == .CURDIR\n",
455 			 gn->name);
456 	return false;
457     }
458     return true;
459 }
460 
461 
462 static FILE *
463 meta_create(BuildMon *pbm, GNode *gn)
464 {
465     FILE *fp;
466     char buf[MAXPATHLEN];
467     char objdir_realpath[MAXPATHLEN];
468     char **ptr;
469     FStr dname;
470     const char *tname;
471     char *fname;
472     const char *cp;
473 
474     fp = NULL;
475 
476     dname = Var_Value(gn, ".OBJDIR");
477     tname = GNode_VarTarget(gn);
478 
479     /* if this succeeds objdir_realpath is realpath of dname */
480     if (!meta_needed(gn, dname.str, objdir_realpath, true))
481 	goto out;
482     dname.str = objdir_realpath;
483 
484     if (metaVerbose) {
485 	char *mp;
486 
487 	/* Describe the target we are building */
488 	(void)Var_Subst("${" MAKE_META_PREFIX "}", gn, VARE_WANTRES, &mp);
489 	/* TODO: handle errors */
490 	if (mp[0] != '\0')
491 	    fprintf(stdout, "%s\n", mp);
492 	free(mp);
493     }
494     /* Get the basename of the target */
495     cp = str_basename(tname);
496 
497     fflush(stdout);
498 
499     if (!writeMeta)
500 	/* Don't create meta data. */
501 	goto out;
502 
503     fname = meta_name(pbm->meta_fname, sizeof pbm->meta_fname,
504 		      dname.str, tname, objdir_realpath);
505 
506 #ifdef DEBUG_META_MODE
507     DEBUG1(META, "meta_create: %s\n", fname);
508 #endif
509 
510     if ((fp = fopen(fname, "w")) == NULL)
511 	Punt("Could not open meta file '%s': %s", fname, strerror(errno));
512 
513     fprintf(fp, "# Meta data file %s\n", fname);
514 
515     printCMDs(gn, fp);
516 
517     fprintf(fp, "CWD %s\n", getcwd(buf, sizeof buf));
518     fprintf(fp, "TARGET %s\n", tname);
519     cp = GNode_VarOodate(gn);
520     if (cp != NULL && *cp != '\0') {
521 	fprintf(fp, "OODATE %s\n", cp);
522     }
523     if (metaEnv) {
524 	for (ptr = environ; *ptr != NULL; ptr++)
525 	    fprintf(fp, "ENV %s\n", *ptr);
526     }
527 
528     fprintf(fp, "-- command output --\n");
529     if (fflush(fp) != 0)
530 	Punt("Cannot write expanded command to meta file: %s",
531 	    strerror(errno));
532 
533     Global_Append(".MAKE.META.FILES", fname);
534     Global_Append(".MAKE.META.CREATED", fname);
535 
536     gn->type |= OP_META;		/* in case anyone wants to know */
537     if (metaSilent) {
538 	    gn->type |= OP_SILENT;
539     }
540  out:
541     FStr_Done(&dname);
542 
543     return fp;
544 }
545 
546 static bool
547 boolValue(const char *s)
548 {
549     switch (*s) {
550     case '0':
551     case 'N':
552     case 'n':
553     case 'F':
554     case 'f':
555 	return false;
556     }
557     return true;
558 }
559 
560 /*
561  * Initialization we need before reading makefiles.
562  */
563 void
564 meta_init(void)
565 {
566 #ifdef USE_FILEMON
567 	/* this allows makefiles to test if we have filemon support */
568 	Global_Set(".MAKE.PATH_FILEMON", filemon_path());
569 #endif
570 }
571 
572 
573 #define get_mode_bf(bf, token) \
574     if ((cp = strstr(make_mode, token)) != NULL) \
575 	bf = boolValue(cp + sizeof (token) - 1)
576 
577 /*
578  * Initialization we need after reading makefiles.
579  */
580 void
581 meta_mode_init(const char *make_mode)
582 {
583     static bool once = false;
584     const char *cp;
585 
586     useMeta = true;
587     useFilemon = true;
588     writeMeta = true;
589 
590     if (make_mode != NULL) {
591 	if (strstr(make_mode, "env") != NULL)
592 	    metaEnv = true;
593 	if (strstr(make_mode, "verb") != NULL)
594 	    metaVerbose = true;
595 	if (strstr(make_mode, "read") != NULL)
596 	    writeMeta = false;
597 	if (strstr(make_mode, "nofilemon") != NULL)
598 	    useFilemon = false;
599 	if (strstr(make_mode, "ignore-cmd") != NULL)
600 	    metaIgnoreCMDs = true;
601 	if (useFilemon)
602 	    get_mode_bf(filemonMissing, "missing-filemon=");
603 	get_mode_bf(metaCurdirOk, "curdirok=");
604 	get_mode_bf(metaMissing, "missing-meta=");
605 	get_mode_bf(metaSilent, "silent=");
606     }
607     if (metaVerbose && !Var_Exists(SCOPE_GLOBAL, MAKE_META_PREFIX)) {
608 	/*
609 	 * The default value for MAKE_META_PREFIX
610 	 * prints the absolute path of the target.
611 	 * This works be cause :H will generate '.' if there is no /
612 	 * and :tA will resolve that to cwd.
613 	 */
614 	Global_Set(MAKE_META_PREFIX,
615 	    "Building ${.TARGET:H:tA}/${.TARGET:T}");
616     }
617     if (once)
618 	return;
619     once = true;
620     memset(&Mybm, 0, sizeof Mybm);
621     /*
622      * We consider ourselves master of all within ${.MAKE.META.BAILIWICK}
623      */
624     (void)Var_Subst("${.MAKE.META.BAILIWICK:O:u:tA}",
625 		    SCOPE_GLOBAL, VARE_WANTRES, &metaBailiwickStr);
626     /* TODO: handle errors */
627     str2Lst_Append(&metaBailiwick, metaBailiwickStr);
628     /*
629      * We ignore any paths that start with ${.MAKE.META.IGNORE_PATHS}
630      */
631     Global_Append(MAKE_META_IGNORE_PATHS,
632 	       "/dev /etc /proc /tmp /var/run /var/tmp ${TMPDIR}");
633     (void)Var_Subst("${" MAKE_META_IGNORE_PATHS ":O:u:tA}",
634 		    SCOPE_GLOBAL, VARE_WANTRES, &metaIgnorePathsStr);
635     /* TODO: handle errors */
636     str2Lst_Append(&metaIgnorePaths, metaIgnorePathsStr);
637 
638     /*
639      * We ignore any paths that match ${.MAKE.META.IGNORE_PATTERNS}
640      */
641     metaIgnorePatterns = Var_Exists(SCOPE_GLOBAL, MAKE_META_IGNORE_PATTERNS);
642     metaIgnoreFilter = Var_Exists(SCOPE_GLOBAL, MAKE_META_IGNORE_FILTER);
643     metaCmpFilter = Var_Exists(SCOPE_GLOBAL, MAKE_META_CMP_FILTER);
644 }
645 
646 /*
647  * In each case below we allow for job==NULL
648  */
649 void
650 meta_job_start(Job *job, GNode *gn)
651 {
652     BuildMon *pbm;
653 
654     if (job != NULL) {
655 	pbm = &job->bm;
656     } else {
657 	pbm = &Mybm;
658     }
659     pbm->mfp = meta_create(pbm, gn);
660 #ifdef USE_FILEMON_ONCE
661     /* compat mode we open the filemon dev once per command */
662     if (job == NULL)
663 	return;
664 #endif
665 #ifdef USE_FILEMON
666     if (pbm->mfp != NULL && useFilemon) {
667 	meta_open_filemon(pbm);
668     } else {
669 	pbm->mon_fd = -1;
670 	pbm->filemon = NULL;
671     }
672 #endif
673 }
674 
675 /*
676  * The child calls this before doing anything.
677  * It does not disturb our state.
678  */
679 void
680 meta_job_child(Job *job MAKE_ATTR_UNUSED)
681 {
682 #ifdef USE_FILEMON
683     BuildMon *pbm;
684 
685     if (job != NULL) {
686 	pbm = &job->bm;
687     } else {
688 	pbm = &Mybm;
689     }
690     if (pbm->mfp != NULL) {
691 	close(fileno(pbm->mfp));
692 	if (useFilemon && pbm->filemon != NULL) {
693 	    pid_t pid;
694 
695 	    pid = getpid();
696 	    if (filemon_setpid_child(pbm->filemon, pid) == -1) {
697 		Punt("Could not set filemon pid: %s", strerror(errno));
698 	    }
699 	}
700     }
701 #endif
702 }
703 
704 void
705 meta_job_parent(Job *job MAKE_ATTR_UNUSED, pid_t pid MAKE_ATTR_UNUSED)
706 {
707 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
708     BuildMon *pbm;
709 
710     if (job != NULL) {
711 	pbm = &job->bm;
712     } else {
713 	pbm = &Mybm;
714     }
715     if (useFilemon && pbm->filemon != NULL) {
716 	filemon_setpid_parent(pbm->filemon, pid);
717     }
718 #endif
719 }
720 
721 int
722 meta_job_fd(Job *job MAKE_ATTR_UNUSED)
723 {
724 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
725     BuildMon *pbm;
726 
727     if (job != NULL) {
728 	pbm = &job->bm;
729     } else {
730 	pbm = &Mybm;
731     }
732     if (useFilemon && pbm->filemon != NULL) {
733 	return filemon_readfd(pbm->filemon);
734     }
735 #endif
736     return -1;
737 }
738 
739 int
740 meta_job_event(Job *job MAKE_ATTR_UNUSED)
741 {
742 #if defined(USE_FILEMON) && !defined(USE_FILEMON_DEV)
743     BuildMon *pbm;
744 
745     if (job != NULL) {
746 	pbm = &job->bm;
747     } else {
748 	pbm = &Mybm;
749     }
750     if (useFilemon && pbm->filemon != NULL) {
751 	return filemon_process(pbm->filemon);
752     }
753 #endif
754     return 0;
755 }
756 
757 void
758 meta_job_error(Job *job, GNode *gn, bool ignerr, int status)
759 {
760     char cwd[MAXPATHLEN];
761     BuildMon *pbm;
762 
763     if (job != NULL) {
764 	pbm = &job->bm;
765 	if (gn == NULL)
766 	    gn = job->node;
767     } else {
768 	pbm = &Mybm;
769     }
770     if (pbm->mfp != NULL) {
771 	fprintf(pbm->mfp, "\n*** Error code %d%s\n",
772 		status, ignerr ? "(ignored)" : "");
773     }
774     if (gn != NULL)
775 	Global_Set(".ERROR_TARGET", GNode_Path(gn));
776     if (getcwd(cwd, sizeof cwd) == NULL)
777 	Punt("Cannot get cwd: %s", strerror(errno));
778 
779     Global_Set(".ERROR_CWD", cwd);
780     if (pbm->meta_fname[0] != '\0') {
781 	Global_Set(".ERROR_META_FILE", pbm->meta_fname);
782     }
783     meta_job_finish(job);
784 }
785 
786 void
787 meta_job_output(Job *job, char *cp, const char *nl)
788 {
789     BuildMon *pbm;
790 
791     if (job != NULL) {
792 	pbm = &job->bm;
793     } else {
794 	pbm = &Mybm;
795     }
796     if (pbm->mfp != NULL) {
797 	if (metaVerbose) {
798 	    static char *meta_prefix = NULL;
799 	    static size_t meta_prefix_len;
800 
801 	    if (meta_prefix == NULL) {
802 		char *cp2;
803 
804 		(void)Var_Subst("${" MAKE_META_PREFIX "}",
805 				SCOPE_GLOBAL, VARE_WANTRES, &meta_prefix);
806 		/* TODO: handle errors */
807 		if ((cp2 = strchr(meta_prefix, '$')) != NULL)
808 		    meta_prefix_len = (size_t)(cp2 - meta_prefix);
809 		else
810 		    meta_prefix_len = strlen(meta_prefix);
811 	    }
812 	    if (strncmp(cp, meta_prefix, meta_prefix_len) == 0) {
813 		cp = strchr(cp + 1, '\n');
814 		if (cp == NULL)
815 		    return;
816 		cp++;
817 	    }
818 	}
819 	fprintf(pbm->mfp, "%s%s", cp, nl);
820     }
821 }
822 
823 int
824 meta_cmd_finish(void *pbmp)
825 {
826     int error = 0;
827     BuildMon *pbm = pbmp;
828 #ifdef USE_FILEMON
829     int x;
830 #endif
831 
832     if (pbm == NULL)
833 	pbm = &Mybm;
834 
835 #ifdef USE_FILEMON
836     if (pbm->filemon != NULL) {
837 	while (filemon_process(pbm->filemon) > 0)
838 	    continue;
839 	if (filemon_close(pbm->filemon) == -1) {
840 	    error = errno;
841 	    Punt("filemon failed: %s", strerror(errno));
842 	}
843 	x = filemon_read(pbm->mfp, pbm->mon_fd);
844 	if (error == 0 && x != 0)
845 	    error = x;
846 	pbm->mon_fd = -1;
847 	pbm->filemon = NULL;
848 	return error;
849     }
850 #endif
851 
852     fprintf(pbm->mfp, "\n");	/* ensure end with newline */
853     return error;
854 }
855 
856 int
857 meta_job_finish(Job *job)
858 {
859     BuildMon *pbm;
860     int error = 0;
861     int x;
862 
863     if (job != NULL) {
864 	pbm = &job->bm;
865     } else {
866 	pbm = &Mybm;
867     }
868     if (pbm->mfp != NULL) {
869 	error = meta_cmd_finish(pbm);
870 	x = fclose(pbm->mfp);
871 	if (error == 0 && x != 0)
872 	    error = errno;
873 	pbm->mfp = NULL;
874 	pbm->meta_fname[0] = '\0';
875     }
876     return error;
877 }
878 
879 void
880 meta_finish(void)
881 {
882     Lst_Done(&metaBailiwick);
883     free(metaBailiwickStr);
884     Lst_Done(&metaIgnorePaths);
885     free(metaIgnorePathsStr);
886 }
887 
888 /*
889  * Fetch a full line from fp - growing bufp if needed
890  * Return length in bufp.
891  */
892 static int
893 fgetLine(char **bufp, size_t *szp, int o, FILE *fp)
894 {
895     char *buf = *bufp;
896     size_t bufsz = *szp;
897     struct stat fs;
898     int x;
899 
900     if (fgets(&buf[o], (int)bufsz - o, fp) != NULL) {
901     check_newline:
902 	x = o + (int)strlen(&buf[o]);
903 	if (buf[x - 1] == '\n')
904 	    return x;
905 	/*
906 	 * We need to grow the buffer.
907 	 * The meta file can give us a clue.
908 	 */
909 	if (fstat(fileno(fp), &fs) == 0) {
910 	    size_t newsz;
911 	    char *p;
912 
913 	    newsz = ROUNDUP(((size_t)fs.st_size / 2), BUFSIZ);
914 	    if (newsz <= bufsz)
915 		newsz = ROUNDUP((size_t)fs.st_size, BUFSIZ);
916 	    if (newsz <= bufsz)
917 		return x;		/* truncated */
918 	    DEBUG2(META, "growing buffer %u -> %u\n",
919 		   (unsigned)bufsz, (unsigned)newsz);
920 	    p = bmake_realloc(buf, newsz);
921 	    *bufp = buf = p;
922 	    *szp = bufsz = newsz;
923 	    /* fetch the rest */
924 	    if (fgets(&buf[x], (int)bufsz - x, fp) == NULL)
925 		return x;		/* truncated! */
926 	    goto check_newline;
927 	}
928     }
929     return 0;
930 }
931 
932 static bool
933 prefix_match(const char *prefix, const char *path)
934 {
935     size_t n = strlen(prefix);
936 
937     return strncmp(path, prefix, n) == 0;
938 }
939 
940 static bool
941 has_any_prefix(const char *path, StringList *prefixes)
942 {
943     StringListNode *ln;
944 
945     for (ln = prefixes->first; ln != NULL; ln = ln->next)
946 	if (prefix_match(ln->datum, path))
947 	    return true;
948     return false;
949 }
950 
951 /* See if the path equals prefix or starts with "prefix/". */
952 static bool
953 path_starts_with(const char *path, const char *prefix)
954 {
955     size_t n = strlen(prefix);
956 
957     if (strncmp(path, prefix, n) != 0)
958 	return false;
959     return path[n] == '\0' || path[n] == '/';
960 }
961 
962 static bool
963 meta_ignore(GNode *gn, const char *p)
964 {
965     char fname[MAXPATHLEN];
966 
967     if (p == NULL)
968 	return true;
969 
970     if (*p == '/') {
971 	cached_realpath(p, fname); /* clean it up */
972 	if (has_any_prefix(fname, &metaIgnorePaths)) {
973 #ifdef DEBUG_META_MODE
974 	    DEBUG1(META, "meta_oodate: ignoring path: %s\n", p);
975 #endif
976 	    return true;
977 	}
978     }
979 
980     if (metaIgnorePatterns) {
981 	const char *expr;
982 	char *pm;
983 
984 	/*
985 	 * XXX: This variable is set on a target GNode but is not one of
986 	 * the usual local variables.  It should be deleted afterwards.
987 	 * Ideally it would not be created in the first place, just like
988 	 * in a .for loop.
989 	 */
990 	Var_Set(gn, ".p.", p);
991 	expr = "${" MAKE_META_IGNORE_PATTERNS ":@m@${.p.:M$m}@}";
992 	(void)Var_Subst(expr, gn, VARE_WANTRES, &pm);
993 	/* TODO: handle errors */
994 	if (pm[0] != '\0') {
995 #ifdef DEBUG_META_MODE
996 	    DEBUG1(META, "meta_oodate: ignoring pattern: %s\n", p);
997 #endif
998 	    free(pm);
999 	    return true;
1000 	}
1001 	free(pm);
1002     }
1003 
1004     if (metaIgnoreFilter) {
1005 	char *fm;
1006 
1007 	/* skip if filter result is empty */
1008 	snprintf(fname, sizeof fname,
1009 		 "${%s:L:${%s:ts:}}",
1010 		 p, MAKE_META_IGNORE_FILTER);
1011 	(void)Var_Subst(fname, gn, VARE_WANTRES, &fm);
1012 	/* TODO: handle errors */
1013 	if (*fm == '\0') {
1014 #ifdef DEBUG_META_MODE
1015 	    DEBUG1(META, "meta_oodate: ignoring filtered: %s\n", p);
1016 #endif
1017 	    free(fm);
1018 	    return true;
1019 	}
1020 	free(fm);
1021     }
1022     return false;
1023 }
1024 
1025 /*
1026  * When running with 'meta' functionality, a target can be out-of-date
1027  * if any of the references in its meta data file is more recent.
1028  * We have to track the latestdir on a per-process basis.
1029  */
1030 #define LCWD_VNAME_FMT ".meta.%d.lcwd"
1031 #define LDIR_VNAME_FMT ".meta.%d.ldir"
1032 
1033 /*
1034  * It is possible that a .meta file is corrupted,
1035  * if we detect this we want to reproduce it.
1036  * Setting oodate true will have that effect.
1037  */
1038 #define CHECK_VALID_META(p) if (!(p != NULL && *p != '\0')) { \
1039     warnx("%s: %u: malformed", fname, lineno); \
1040     oodate = true; \
1041     continue; \
1042     }
1043 
1044 #define DEQUOTE(p) if (*p == '\'') {	\
1045     char *ep; \
1046     p++; \
1047     if ((ep = strchr(p, '\'')) != NULL) \
1048 	*ep = '\0'; \
1049     }
1050 
1051 static void
1052 append_if_new(StringList *list, const char *str)
1053 {
1054     StringListNode *ln;
1055 
1056     for (ln = list->first; ln != NULL; ln = ln->next)
1057 	if (strcmp(ln->datum, str) == 0)
1058 	    return;
1059     Lst_Append(list, bmake_strdup(str));
1060 }
1061 
1062 /* A "reserved" variable to store the command to be filtered */
1063 #define META_CMD_FILTER_VAR ".MAKE.cmd_filtered"
1064 
1065 static char *
1066 meta_filter_cmd(GNode *gn, char *s)
1067 {
1068     Var_Set(gn, META_CMD_FILTER_VAR, s);
1069     Var_Subst("${" META_CMD_FILTER_VAR ":${" MAKE_META_CMP_FILTER ":ts:}}", gn, VARE_WANTRES, &s);
1070     return s;
1071 }
1072 
1073 static int
1074 meta_cmd_cmp(GNode *gn, char *a, char *b, bool filter)
1075 {
1076     int rc;
1077 
1078     rc = strcmp(a, b);
1079     if (rc == 0 || !filter)
1080 	return rc;
1081     a = meta_filter_cmd(gn, a);
1082     b = meta_filter_cmd(gn, b);
1083     rc = strcmp(a, b);
1084     free(a);
1085     free(b);
1086     Var_Delete(gn, META_CMD_FILTER_VAR);
1087     return rc;
1088 }
1089 
1090 bool
1091 meta_oodate(GNode *gn, bool oodate)
1092 {
1093     static char *tmpdir = NULL;
1094     static char cwd[MAXPATHLEN];
1095     char lcwd_vname[64];
1096     char ldir_vname[64];
1097     char lcwd[MAXPATHLEN];
1098     char latestdir[MAXPATHLEN];
1099     char fname[MAXPATHLEN];
1100     char fname1[MAXPATHLEN];
1101     char fname2[MAXPATHLEN];
1102     char fname3[MAXPATHLEN];
1103     FStr dname;
1104     const char *tname;
1105     char *p;
1106     char *link_src;
1107     char *move_target;
1108     static size_t cwdlen = 0;
1109     static size_t tmplen = 0;
1110     FILE *fp;
1111     bool needOODATE = false;
1112     StringList missingFiles;
1113     bool have_filemon = false;
1114     bool cmp_filter;
1115 
1116     if (oodate)
1117 	return oodate;		/* we're done */
1118 
1119     dname = Var_Value(gn, ".OBJDIR");
1120     tname = GNode_VarTarget(gn);
1121 
1122     /* if this succeeds fname3 is realpath of dname */
1123     if (!meta_needed(gn, dname.str, fname3, false))
1124 	goto oodate_out;
1125     dname.str = fname3;
1126 
1127     Lst_Init(&missingFiles);
1128 
1129     /*
1130      * We need to check if the target is out-of-date. This includes
1131      * checking if the expanded command has changed. This in turn
1132      * requires that all variables are set in the same way that they
1133      * would be if the target needs to be re-built.
1134      */
1135     GNode_SetLocalVars(gn);
1136 
1137     meta_name(fname, sizeof fname, dname.str, tname, dname.str);
1138 
1139 #ifdef DEBUG_META_MODE
1140     DEBUG1(META, "meta_oodate: %s\n", fname);
1141 #endif
1142 
1143     if ((fp = fopen(fname, "r")) != NULL) {
1144 	static char *buf = NULL;
1145 	static size_t bufsz;
1146 	unsigned lineno = 0;
1147 	int lastpid = 0;
1148 	int pid;
1149 	int x;
1150 	StringListNode *cmdNode;
1151 	struct cached_stat cst;
1152 
1153 	if (buf == NULL) {
1154 	    bufsz = 8 * BUFSIZ;
1155 	    buf = bmake_malloc(bufsz);
1156 	}
1157 
1158 	if (cwdlen == 0) {
1159 	    if (getcwd(cwd, sizeof cwd) == NULL)
1160 		err(1, "Could not get current working directory");
1161 	    cwdlen = strlen(cwd);
1162 	}
1163 	strlcpy(lcwd, cwd, sizeof lcwd);
1164 	strlcpy(latestdir, cwd, sizeof latestdir);
1165 
1166 	if (tmpdir == NULL) {
1167 	    tmpdir = getTmpdir();
1168 	    tmplen = strlen(tmpdir);
1169 	}
1170 
1171 	/* we want to track all the .meta we read */
1172 	Global_Append(".MAKE.META.FILES", fname);
1173 
1174 	cmp_filter = metaCmpFilter || Var_Exists(gn, MAKE_META_CMP_FILTER);
1175 
1176 	cmdNode = gn->commands.first;
1177 	while (!oodate && (x = fgetLine(&buf, &bufsz, 0, fp)) > 0) {
1178 	    lineno++;
1179 	    if (buf[x - 1] == '\n')
1180 		buf[x - 1] = '\0';
1181 	    else {
1182 		warnx("%s: %u: line truncated at %u", fname, lineno, x);
1183 		oodate = true;
1184 		break;
1185 	    }
1186 	    link_src = NULL;
1187 	    move_target = NULL;
1188 	    /* Find the start of the build monitor section. */
1189 	    if (!have_filemon) {
1190 		if (strncmp(buf, "-- filemon", 10) == 0) {
1191 		    have_filemon = true;
1192 		    continue;
1193 		}
1194 		if (strncmp(buf, "# buildmon", 10) == 0) {
1195 		    have_filemon = true;
1196 		    continue;
1197 		}
1198 	    }
1199 
1200 	    /* Delimit the record type. */
1201 	    p = buf;
1202 #ifdef DEBUG_META_MODE
1203 	    DEBUG3(META, "%s: %u: %s\n", fname, lineno, buf);
1204 #endif
1205 	    strsep(&p, " ");
1206 	    if (have_filemon) {
1207 		/*
1208 		 * We are in the 'filemon' output section.
1209 		 * Each record from filemon follows the general form:
1210 		 *
1211 		 * <key> <pid> <data>
1212 		 *
1213 		 * Where:
1214 		 * <key> is a single letter, denoting the syscall.
1215 		 * <pid> is the process that made the syscall.
1216 		 * <data> is the arguments (of interest).
1217 		 */
1218 		switch(buf[0]) {
1219 		case '#':		/* comment */
1220 		case 'V':		/* version */
1221 		    break;
1222 		default:
1223 		    /*
1224 		     * We need to track pathnames per-process.
1225 		     *
1226 		     * Each process run by make starts off in the 'CWD'
1227 		     * recorded in the .meta file, if it chdirs ('C')
1228 		     * elsewhere we need to track that - but only for
1229 		     * that process.  If it forks ('F'), we initialize
1230 		     * the child to have the same cwd as its parent.
1231 		     *
1232 		     * We also need to track the 'latestdir' of
1233 		     * interest.  This is usually the same as cwd, but
1234 		     * not if a process is reading directories.
1235 		     *
1236 		     * Each time we spot a different process ('pid')
1237 		     * we save the current value of 'latestdir' in a
1238 		     * variable qualified by 'lastpid', and
1239 		     * re-initialize 'latestdir' to any pre-saved
1240 		     * value for the current 'pid' and 'CWD' if none.
1241 		     */
1242 		    CHECK_VALID_META(p);
1243 		    pid = atoi(p);
1244 		    if (pid > 0 && pid != lastpid) {
1245 			FStr ldir;
1246 
1247 			if (lastpid > 0) {
1248 			    /* We need to remember these. */
1249 			    Global_Set(lcwd_vname, lcwd);
1250 			    Global_Set(ldir_vname, latestdir);
1251 			}
1252 			snprintf(lcwd_vname, sizeof lcwd_vname, LCWD_VNAME_FMT, pid);
1253 			snprintf(ldir_vname, sizeof ldir_vname, LDIR_VNAME_FMT, pid);
1254 			lastpid = pid;
1255 			ldir = Var_Value(SCOPE_GLOBAL, ldir_vname);
1256 			if (ldir.str != NULL) {
1257 			    strlcpy(latestdir, ldir.str, sizeof latestdir);
1258 			    FStr_Done(&ldir);
1259 			}
1260 			ldir = Var_Value(SCOPE_GLOBAL, lcwd_vname);
1261 			if (ldir.str != NULL) {
1262 			    strlcpy(lcwd, ldir.str, sizeof lcwd);
1263 			    FStr_Done(&ldir);
1264 			}
1265 		    }
1266 		    /* Skip past the pid. */
1267 		    if (strsep(&p, " ") == NULL)
1268 			continue;
1269 #ifdef DEBUG_META_MODE
1270 		    if (DEBUG(META))
1271 			debug_printf("%s: %u: %d: %c: cwd=%s lcwd=%s ldir=%s\n",
1272 				     fname, lineno,
1273 				     pid, buf[0], cwd, lcwd, latestdir);
1274 #endif
1275 		    break;
1276 		}
1277 
1278 		CHECK_VALID_META(p);
1279 
1280 		/* Process according to record type. */
1281 		switch (buf[0]) {
1282 		case 'X':		/* eXit */
1283 		    Var_Delete(SCOPE_GLOBAL, lcwd_vname);
1284 		    Var_Delete(SCOPE_GLOBAL, ldir_vname);
1285 		    lastpid = 0;	/* no need to save ldir_vname */
1286 		    break;
1287 
1288 		case 'F':		/* [v]Fork */
1289 		    {
1290 			char cldir[64];
1291 			int child;
1292 
1293 			child = atoi(p);
1294 			if (child > 0) {
1295 			    snprintf(cldir, sizeof cldir, LCWD_VNAME_FMT, child);
1296 			    Global_Set(cldir, lcwd);
1297 			    snprintf(cldir, sizeof cldir, LDIR_VNAME_FMT, child);
1298 			    Global_Set(cldir, latestdir);
1299 #ifdef DEBUG_META_MODE
1300 			    if (DEBUG(META))
1301 				debug_printf(
1302 					"%s: %u: %d: cwd=%s lcwd=%s ldir=%s\n",
1303 					fname, lineno,
1304 					child, cwd, lcwd, latestdir);
1305 #endif
1306 			}
1307 		    }
1308 		    break;
1309 
1310 		case 'C':		/* Chdir */
1311 		    /* Update lcwd and latest directory. */
1312 		    strlcpy(latestdir, p, sizeof latestdir);
1313 		    strlcpy(lcwd, p, sizeof lcwd);
1314 		    Global_Set(lcwd_vname, lcwd);
1315 		    Global_Set(ldir_vname, lcwd);
1316 #ifdef DEBUG_META_MODE
1317 		    DEBUG4(META, "%s: %u: cwd=%s ldir=%s\n",
1318 			   fname, lineno, cwd, lcwd);
1319 #endif
1320 		    break;
1321 
1322 		case 'M':		/* renaMe */
1323 		    /*
1324 		     * For 'M'oves we want to check
1325 		     * the src as for 'R'ead
1326 		     * and the target as for 'W'rite.
1327 		     */
1328 		    {
1329 			char *cp = p;	/* save this for a second */
1330 			/* now get target */
1331 			if (strsep(&p, " ") == NULL)
1332 			    continue;
1333 			CHECK_VALID_META(p);
1334 			move_target = p;
1335 			p = cp;
1336 		    }
1337 		    /* 'L' and 'M' put single quotes around the args */
1338 		    DEQUOTE(p);
1339 		    DEQUOTE(move_target);
1340 		    /* FALLTHROUGH */
1341 		case 'D':		/* unlink */
1342 		    if (*p == '/') {
1343 			/* remove any missingFiles entries that match p */
1344 			StringListNode *ln = missingFiles.first;
1345 			while (ln != NULL) {
1346 			    StringListNode *next = ln->next;
1347 			    if (path_starts_with(ln->datum, p)) {
1348 				free(ln->datum);
1349 				Lst_Remove(&missingFiles, ln);
1350 			    }
1351 			    ln = next;
1352 			}
1353 		    }
1354 		    if (buf[0] == 'M') {
1355 			/* the target of the mv is a file 'W'ritten */
1356 #ifdef DEBUG_META_MODE
1357 			DEBUG2(META, "meta_oodate: M %s -> %s\n",
1358 			       p, move_target);
1359 #endif
1360 			p = move_target;
1361 			goto check_write;
1362 		    }
1363 		    break;
1364 		case 'L':		/* Link */
1365 		    /*
1366 		     * For 'L'inks check
1367 		     * the src as for 'R'ead
1368 		     * and the target as for 'W'rite.
1369 		     */
1370 		    link_src = p;
1371 		    /* now get target */
1372 		    if (strsep(&p, " ") == NULL)
1373 			continue;
1374 		    CHECK_VALID_META(p);
1375 		    /* 'L' and 'M' put single quotes around the args */
1376 		    DEQUOTE(p);
1377 		    DEQUOTE(link_src);
1378 #ifdef DEBUG_META_MODE
1379 		    DEBUG2(META, "meta_oodate: L %s -> %s\n", link_src, p);
1380 #endif
1381 		    /* FALLTHROUGH */
1382 		case 'W':		/* Write */
1383 		check_write:
1384 		    /*
1385 		     * If a file we generated within our bailiwick
1386 		     * but outside of .OBJDIR is missing,
1387 		     * we need to do it again.
1388 		     */
1389 		    /* ignore non-absolute paths */
1390 		    if (*p != '/')
1391 			break;
1392 
1393 		    if (Lst_IsEmpty(&metaBailiwick))
1394 			break;
1395 
1396 		    /* ignore cwd - normal dependencies handle those */
1397 		    if (strncmp(p, cwd, cwdlen) == 0)
1398 			break;
1399 
1400 		    if (!has_any_prefix(p, &metaBailiwick))
1401 			break;
1402 
1403 		    /* tmpdir might be within */
1404 		    if (tmplen > 0 && strncmp(p, tmpdir, tmplen) == 0)
1405 			break;
1406 
1407 		    /* ignore anything containing the string "tmp" */
1408 		    /* XXX: The arguments to strstr must be swapped. */
1409 		    if (strstr("tmp", p) != NULL)
1410 			break;
1411 
1412 		    if ((link_src != NULL && cached_lstat(p, &cst) < 0) ||
1413 			(link_src == NULL && cached_stat(p, &cst) < 0)) {
1414 			if (!meta_ignore(gn, p))
1415 			    append_if_new(&missingFiles, p);
1416 		    }
1417 		    break;
1418 		check_link_src:
1419 		    p = link_src;
1420 		    link_src = NULL;
1421 #ifdef DEBUG_META_MODE
1422 		    DEBUG1(META, "meta_oodate: L src %s\n", p);
1423 #endif
1424 		    /* FALLTHROUGH */
1425 		case 'R':		/* Read */
1426 		case 'E':		/* Exec */
1427 		    /*
1428 		     * Check for runtime files that can't
1429 		     * be part of the dependencies because
1430 		     * they are _expected_ to change.
1431 		     */
1432 		    if (meta_ignore(gn, p))
1433 			break;
1434 
1435 		    /*
1436 		     * The rest of the record is the file name.
1437 		     * Check if it's not an absolute path.
1438 		     */
1439 		    {
1440 			char *sdirs[4];
1441 			char **sdp;
1442 			int sdx = 0;
1443 			bool found = false;
1444 
1445 			if (*p == '/') {
1446 			    sdirs[sdx++] = p; /* done */
1447 			} else {
1448 			    if (strcmp(".", p) == 0)
1449 				continue; /* no point */
1450 
1451 			    /* Check vs latestdir */
1452 			    if (snprintf(fname1, sizeof fname1, "%s/%s", latestdir, p) < (int)(sizeof fname1))
1453 				sdirs[sdx++] = fname1;
1454 
1455 			    if (strcmp(latestdir, lcwd) != 0) {
1456 				/* Check vs lcwd */
1457 				if (snprintf(fname2, sizeof fname2, "%s/%s", lcwd, p) < (int)(sizeof fname2))
1458 				    sdirs[sdx++] = fname2;
1459 			    }
1460 			    if (strcmp(lcwd, cwd) != 0) {
1461 				/* Check vs cwd */
1462 				if (snprintf(fname3, sizeof fname3, "%s/%s", cwd, p) < (int)(sizeof fname3))
1463 				    sdirs[sdx++] = fname3;
1464 			    }
1465 			}
1466 			sdirs[sdx++] = NULL;
1467 
1468 			for (sdp = sdirs; *sdp != NULL && !found; sdp++) {
1469 #ifdef DEBUG_META_MODE
1470 			    DEBUG3(META, "%s: %u: looking for: %s\n",
1471 				   fname, lineno, *sdp);
1472 #endif
1473 			    if (cached_stat(*sdp, &cst) == 0) {
1474 				found = true;
1475 				p = *sdp;
1476 			    }
1477 			}
1478 			if (found) {
1479 #ifdef DEBUG_META_MODE
1480 			    DEBUG3(META, "%s: %u: found: %s\n",
1481 				   fname, lineno, p);
1482 #endif
1483 			    if (!S_ISDIR(cst.cst_mode) &&
1484 				cst.cst_mtime > gn->mtime) {
1485 				DEBUG3(META, "%s: %u: file '%s' is newer than the target...\n",
1486 				       fname, lineno, p);
1487 				oodate = true;
1488 			    } else if (S_ISDIR(cst.cst_mode)) {
1489 				/* Update the latest directory. */
1490 				cached_realpath(p, latestdir);
1491 			    }
1492 			} else if (errno == ENOENT && *p == '/' &&
1493 				   strncmp(p, cwd, cwdlen) != 0) {
1494 			    /*
1495 			     * A referenced file outside of CWD is missing.
1496 			     * We cannot catch every eventuality here...
1497 			     */
1498 			    append_if_new(&missingFiles, p);
1499 			}
1500 		    }
1501 		    if (buf[0] == 'E') {
1502 			/* previous latestdir is no longer relevant */
1503 			strlcpy(latestdir, lcwd, sizeof latestdir);
1504 		    }
1505 		    break;
1506 		default:
1507 		    break;
1508 		}
1509 		if (!oodate && buf[0] == 'L' && link_src != NULL)
1510 		    goto check_link_src;
1511 	    } else if (strcmp(buf, "CMD") == 0) {
1512 		/*
1513 		 * Compare the current command with the one in the
1514 		 * meta data file.
1515 		 */
1516 		if (cmdNode == NULL) {
1517 		    DEBUG2(META, "%s: %u: there were more build commands in the meta data file than there are now...\n",
1518 			   fname, lineno);
1519 		    oodate = true;
1520 		} else {
1521 		    const char *cp;
1522 		    char *cmd = cmdNode->datum;
1523 		    bool hasOODATE = false;
1524 
1525 		    if (strstr(cmd, "$?") != NULL)
1526 			hasOODATE = true;
1527 		    else if ((cp = strstr(cmd, ".OODATE")) != NULL) {
1528 			/* check for $[{(].OODATE[:)}] */
1529 			if (cp > cmd + 2 && cp[-2] == '$')
1530 			    hasOODATE = true;
1531 		    }
1532 		    if (hasOODATE) {
1533 			needOODATE = true;
1534 			DEBUG2(META, "%s: %u: cannot compare command using .OODATE\n",
1535 			       fname, lineno);
1536 		    }
1537 		    (void)Var_Subst(cmd, gn, VARE_UNDEFERR, &cmd);
1538 		    /* TODO: handle errors */
1539 
1540 		    if ((cp = strchr(cmd, '\n')) != NULL) {
1541 			int n;
1542 
1543 			/*
1544 			 * This command contains newlines, we need to
1545 			 * fetch more from the .meta file before we
1546 			 * attempt a comparison.
1547 			 */
1548 			/* first put the newline back at buf[x - 1] */
1549 			buf[x - 1] = '\n';
1550 			do {
1551 			    /* now fetch the next line */
1552 			    if ((n = fgetLine(&buf, &bufsz, x, fp)) <= 0)
1553 				break;
1554 			    x = n;
1555 			    lineno++;
1556 			    if (buf[x - 1] != '\n') {
1557 				warnx("%s: %u: line truncated at %u", fname, lineno, x);
1558 				break;
1559 			    }
1560 			    cp = strchr(cp + 1, '\n');
1561 			} while (cp != NULL);
1562 			if (buf[x - 1] == '\n')
1563 			    buf[x - 1] = '\0';
1564 		    }
1565 		    if (p != NULL &&
1566 			!hasOODATE &&
1567 			!(gn->type & OP_NOMETA_CMP) &&
1568 			(meta_cmd_cmp(gn, p, cmd, cmp_filter) != 0)) {
1569 			DEBUG4(META, "%s: %u: a build command has changed\n%s\nvs\n%s\n",
1570 			       fname, lineno, p, cmd);
1571 			if (!metaIgnoreCMDs)
1572 			    oodate = true;
1573 		    }
1574 		    free(cmd);
1575 		    cmdNode = cmdNode->next;
1576 		}
1577 	    } else if (strcmp(buf, "CWD") == 0) {
1578 		/*
1579 		 * Check if there are extra commands now
1580 		 * that weren't in the meta data file.
1581 		 */
1582 		if (!oodate && cmdNode != NULL) {
1583 		    DEBUG2(META, "%s: %u: there are extra build commands now that weren't in the meta data file\n",
1584 			   fname, lineno);
1585 		    oodate = true;
1586 		}
1587 		CHECK_VALID_META(p);
1588 		if (strcmp(p, cwd) != 0) {
1589 		    DEBUG4(META, "%s: %u: the current working directory has changed from '%s' to '%s'\n",
1590 			   fname, lineno, p, curdir);
1591 		    oodate = true;
1592 		}
1593 	    }
1594 	}
1595 
1596 	fclose(fp);
1597 	if (!Lst_IsEmpty(&missingFiles)) {
1598 	    DEBUG2(META, "%s: missing files: %s...\n",
1599 		   fname, (char *)missingFiles.first->datum);
1600 	    oodate = true;
1601 	}
1602 	if (!oodate && !have_filemon && filemonMissing) {
1603 	    DEBUG1(META, "%s: missing filemon data\n", fname);
1604 	    oodate = true;
1605 	}
1606     } else {
1607 	if (writeMeta && (metaMissing || (gn->type & OP_META))) {
1608 	    const char *cp = NULL;
1609 
1610 	    /* if target is in .CURDIR we do not need a meta file */
1611 	    if (gn->path != NULL && (cp = strrchr(gn->path, '/')) != NULL &&
1612 		(cp > gn->path)) {
1613 		if (strncmp(curdir, gn->path, (size_t)(cp - gn->path)) != 0) {
1614 		    cp = NULL;		/* not in .CURDIR */
1615 		}
1616 	    }
1617 	    if (cp == NULL) {
1618 		DEBUG1(META, "%s: required but missing\n", fname);
1619 		oodate = true;
1620 		needOODATE = true;	/* assume the worst */
1621 	    }
1622 	}
1623     }
1624 
1625     Lst_DoneCall(&missingFiles, free);
1626 
1627     if (oodate && needOODATE) {
1628 	/*
1629 	 * Target uses .OODATE which is empty; or we wouldn't be here.
1630 	 * We have decided it is oodate, so .OODATE needs to be set.
1631 	 * All we can sanely do is set it to .ALLSRC.
1632 	 */
1633 	Var_Delete(gn, OODATE);
1634 	Var_Set(gn, OODATE, GNode_VarAllsrc(gn));
1635     }
1636 
1637  oodate_out:
1638     FStr_Done(&dname);
1639     return oodate;
1640 }
1641 
1642 /* support for compat mode */
1643 
1644 static int childPipe[2];
1645 
1646 void
1647 meta_compat_start(void)
1648 {
1649 #ifdef USE_FILEMON_ONCE
1650     /*
1651      * We need to re-open filemon for each cmd.
1652      */
1653     BuildMon *pbm = &Mybm;
1654 
1655     if (pbm->mfp != NULL && useFilemon) {
1656 	meta_open_filemon(pbm);
1657     } else {
1658 	pbm->mon_fd = -1;
1659 	pbm->filemon = NULL;
1660     }
1661 #endif
1662     if (pipe(childPipe) < 0)
1663 	Punt("Cannot create pipe: %s", strerror(errno));
1664     /* Set close-on-exec flag for both */
1665     (void)fcntl(childPipe[0], F_SETFD, FD_CLOEXEC);
1666     (void)fcntl(childPipe[1], F_SETFD, FD_CLOEXEC);
1667 }
1668 
1669 void
1670 meta_compat_child(void)
1671 {
1672     meta_job_child(NULL);
1673     if (dup2(childPipe[1], 1) < 0 || dup2(1, 2) < 0)
1674 	execDie("dup2", "pipe");
1675 }
1676 
1677 void
1678 meta_compat_parent(pid_t child)
1679 {
1680     int outfd, metafd, maxfd, nfds;
1681     char buf[BUFSIZ+1];
1682     fd_set readfds;
1683 
1684     meta_job_parent(NULL, child);
1685     close(childPipe[1]);			/* child side */
1686     outfd = childPipe[0];
1687 #ifdef USE_FILEMON
1688     metafd = Mybm.filemon != NULL ? filemon_readfd(Mybm.filemon) : -1;
1689 #else
1690     metafd = -1;
1691 #endif
1692     maxfd = -1;
1693     if (outfd > maxfd)
1694 	    maxfd = outfd;
1695     if (metafd > maxfd)
1696 	    maxfd = metafd;
1697 
1698     while (outfd != -1 || metafd != -1) {
1699 	FD_ZERO(&readfds);
1700 	if (outfd != -1) {
1701 	    FD_SET(outfd, &readfds);
1702 	}
1703 	if (metafd != -1) {
1704 	    FD_SET(metafd, &readfds);
1705 	}
1706 	nfds = select(maxfd + 1, &readfds, NULL, NULL, NULL);
1707 	if (nfds == -1) {
1708 	    if (errno == EINTR)
1709 		continue;
1710 	    err(1, "select");
1711 	}
1712 
1713 	if (outfd != -1 && FD_ISSET(outfd, &readfds) != 0) do {
1714 	    /* XXX this is not line-buffered */
1715 	    ssize_t nread = read(outfd, buf, sizeof buf - 1);
1716 	    if (nread == -1)
1717 		err(1, "read");
1718 	    if (nread == 0) {
1719 		close(outfd);
1720 		outfd = -1;
1721 		break;
1722 	    }
1723 	    fwrite(buf, 1, (size_t)nread, stdout);
1724 	    fflush(stdout);
1725 	    buf[nread] = '\0';
1726 	    meta_job_output(NULL, buf, "");
1727 	} while (false);
1728 	if (metafd != -1 && FD_ISSET(metafd, &readfds) != 0) {
1729 	    if (meta_job_event(NULL) <= 0)
1730 		metafd = -1;
1731 	}
1732     }
1733 }
1734 
1735 #endif /* USE_META */
1736