xref: /freebsd/sbin/rcorder/rcorder.c (revision 3078531de10dcae44b253a35125c949ff4235284)
1 # if 0
2 /*	$NetBSD: rcorder.c,v 1.7 2000/08/04 07:33:55 enami Exp $	*/
3 #endif
4 
5 /*-
6  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
7  *
8  * Copyright (c) 1998, 1999 Matthew R. Green
9  * All rights reserved.
10  * Copyright (c) 1998
11  * 	Perry E. Metzger.  All rights reserved.
12  * Copyright (c) 2020
13  *     Boris N. Lytochkin. All rights reserved.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. All advertising materials mentioning features or use of this software
24  *    must display the following acknowledgement:
25  *	This product includes software developed for the NetBSD Project
26  *	by Perry E. Metzger.
27  * 4. The name of the author may not be used to endorse or promote products
28  *    derived from this software without specific prior written permission.
29  *
30  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40  */
41 
42 #include <sys/types.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/stat.h>
46 
47 #include <err.h>
48 #include <stdio.h>
49 #include <libutil.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <unistd.h>
53 #include <libgen.h>
54 #include <stdbool.h>
55 
56 #include "ealloc.h"
57 #include "sprite.h"
58 #include "hash.h"
59 
60 #ifdef DEBUG
61 static int debug = 0;
62 # define	DPRINTF(args) if (debug) { fflush(stdout); fprintf args; }
63 #else
64 # define	DPRINTF(args)
65 #endif
66 
67 #define REQUIRE_STR	"# REQUIRE:"
68 #define REQUIRE_LEN	(sizeof(REQUIRE_STR) - 1)
69 #define REQUIRES_STR	"# REQUIRES:"
70 #define REQUIRES_LEN	(sizeof(REQUIRES_STR) - 1)
71 #define PROVIDE_STR	"# PROVIDE:"
72 #define PROVIDE_LEN	(sizeof(PROVIDE_STR) - 1)
73 #define PROVIDES_STR	"# PROVIDES:"
74 #define PROVIDES_LEN	(sizeof(PROVIDES_STR) - 1)
75 #define BEFORE_STR	"# BEFORE:"
76 #define BEFORE_LEN	(sizeof(BEFORE_STR) - 1)
77 #define KEYWORD_STR	"# KEYWORD:"
78 #define KEYWORD_LEN	(sizeof(KEYWORD_STR) - 1)
79 #define KEYWORDS_STR	"# KEYWORDS:"
80 #define KEYWORDS_LEN	(sizeof(KEYWORDS_STR) - 1)
81 
82 #define	FAKE_PROV_NAME	"fake_prov_"
83 
84 static int exit_code;
85 static int file_count;
86 static char **file_list;
87 
88 #define TRUE 1
89 #define FALSE 0
90 typedef bool flag;
91 #define SET TRUE
92 #define RESET FALSE
93 
94 static flag do_graphviz = false;
95 static flag do_parallel = false;
96 
97 static Hash_Table provide_hash_s, *provide_hash;
98 
99 typedef struct provnode provnode;
100 typedef struct filenode filenode;
101 typedef struct f_provnode f_provnode;
102 typedef struct f_reqnode f_reqnode;
103 typedef struct strnodelist strnodelist;
104 
105 struct provnode {
106 	flag		head;
107 	flag		in_progress;
108 	int		sequence;
109 	filenode	*fnode;
110 	provnode	*next, *last;
111 };
112 
113 struct f_provnode {
114 	provnode	*pnode;
115 	Hash_Entry	*entry;
116 	f_provnode	*next;
117 };
118 
119 struct f_reqnode {
120 	Hash_Entry	*entry;
121 	f_reqnode	*next;
122 };
123 
124 struct strnodelist {
125 	filenode	*node;
126 	strnodelist	*next;
127 	char		s[1];
128 };
129 
130 struct filenode {
131 	char		*filename;
132 	flag		in_progress;
133 	filenode	*next, *last;
134 	f_reqnode	*req_list;
135 	f_provnode	*prov_list;
136 	strnodelist	*keyword_list;
137 	int		issues_count;
138 	int		sequence;
139 };
140 
141 static filenode fn_head_s, *fn_head, **fn_seqlist;
142 static int max_sequence = 0;
143 
144 static strnodelist *bl_list;
145 static strnodelist *keep_list;
146 static strnodelist *skip_list;
147 
148 static void do_file(filenode *fnode, strnodelist *);
149 static void strnode_add(strnodelist **, char *, filenode *);
150 static int skip_ok(filenode *fnode);
151 static int keep_ok(filenode *fnode);
152 static char *generate_loop_for_req(strnodelist *, provnode *, filenode *);
153 static void satisfy_req(f_reqnode *rnode, filenode *fnode, strnodelist *);
154 static void crunch_file(char *);
155 static void parse_require(filenode *, char *);
156 static void parse_provide(filenode *, char *);
157 static void parse_before(filenode *, char *);
158 static void parse_keywords(filenode *, char *);
159 static filenode *filenode_new(char *);
160 static void add_require(filenode *, char *);
161 static void add_provide(filenode *, char *);
162 static void add_before(filenode *, char *);
163 static void add_keyword(filenode *, char *);
164 static void insert_before(void);
165 static Hash_Entry *make_fake_provision(filenode *);
166 static void crunch_all_files(void);
167 static void initialize(void);
168 static void generate_graphviz_header(void);
169 static void generate_graphviz_footer(void);
170 static void generate_graphviz_file_links(Hash_Entry *, filenode *);
171 static void generate_graphviz_providers(void);
172 static inline int is_fake_prov(const char *);
173 static int sequence_cmp(const void *, const void *);
174 static void generate_ordering(void);
175 
176 int
177 main(int argc, char *argv[])
178 {
179 	int ch;
180 
181 	while ((ch = getopt(argc, argv, "dgk:ps:")) != -1)
182 		switch (ch) {
183 		case 'd':
184 #ifdef DEBUG
185 			debug = 1;
186 #else
187 			warnx("debugging not compiled in, -d ignored");
188 #endif
189 			break;
190 		case 'g':
191 			do_graphviz = true;
192 			break;
193 		case 'k':
194 			strnode_add(&keep_list, optarg, 0);
195 			break;
196 		case 'p':
197 			do_parallel = true;
198 			break;
199 		case 's':
200 			strnode_add(&skip_list, optarg, 0);
201 			break;
202 		default:
203 			/* XXX should crunch it? */
204 			break;
205 		}
206 	argc -= optind;
207 	argv += optind;
208 
209 	file_count = argc;
210 	file_list = argv;
211 
212 	DPRINTF((stderr, "parse_args\n"));
213 	initialize();
214 	DPRINTF((stderr, "initialize\n"));
215 	generate_graphviz_header();
216 	crunch_all_files();
217 	DPRINTF((stderr, "crunch_all_files\n"));
218 	generate_graphviz_providers();
219 	generate_ordering();
220 	DPRINTF((stderr, "generate_ordering\n"));
221 	generate_graphviz_footer();
222 
223 	exit(exit_code);
224 }
225 
226 /*
227  * initialise various variables.
228  */
229 static void
230 initialize(void)
231 {
232 
233 	fn_head = &fn_head_s;
234 
235 	provide_hash = &provide_hash_s;
236 	Hash_InitTable(provide_hash, file_count);
237 }
238 
239 /* generic function to insert a new strnodelist element */
240 static void
241 strnode_add(strnodelist **listp, char *s, filenode *fnode)
242 {
243 	strnodelist *ent;
244 
245 	ent = emalloc(sizeof *ent + strlen(s));
246 	ent->node = fnode;
247 	strcpy(ent->s, s);
248 	ent->next = *listp;
249 	*listp = ent;
250 }
251 
252 /*
253  * below are the functions that deal with creating the lists
254  * from the filename's given dependencies and provisions
255  * in each of these files.  no ordering or checking is done here.
256  */
257 
258 /*
259  * we have a new filename, create a new filenode structure.
260  * fill in the bits, and put it in the filenode linked list
261  */
262 static filenode *
263 filenode_new(char *filename)
264 {
265 	filenode *temp;
266 
267 	temp = emalloc(sizeof(*temp));
268 	memset(temp, 0, sizeof(*temp));
269 	temp->filename = estrdup(filename);
270 	temp->req_list = NULL;
271 	temp->prov_list = NULL;
272 	temp->keyword_list = NULL;
273 	temp->in_progress = RESET;
274 	/*
275 	 * link the filenode into the list of filenodes.
276 	 * note that the double linking means we can delete a
277 	 * filenode without searching for where it belongs.
278 	 */
279 	temp->next = fn_head->next;
280 	if (temp->next != NULL)
281 		temp->next->last = temp;
282 	temp->last = fn_head;
283 	fn_head->next = temp;
284 	return (temp);
285 }
286 
287 /*
288  * add a requirement to a filenode.
289  */
290 static void
291 add_require(filenode *fnode, char *s)
292 {
293 	Hash_Entry *entry;
294 	f_reqnode *rnode;
295 	int new;
296 
297 	entry = Hash_CreateEntry(provide_hash, s, &new);
298 	if (new)
299 		Hash_SetValue(entry, NULL);
300 	rnode = emalloc(sizeof(*rnode));
301 	rnode->entry = entry;
302 	rnode->next = fnode->req_list;
303 	fnode->req_list = rnode;
304 }
305 
306 /*
307  * add a provision to a filenode.  if this provision doesn't
308  * have a head node, create one here.
309  */
310 static void
311 add_provide(filenode *fnode, char *s)
312 {
313 	Hash_Entry *entry;
314 	f_provnode *f_pnode;
315 	provnode *pnode, *head;
316 	int new;
317 
318 	entry = Hash_CreateEntry(provide_hash, s, &new);
319 	head = Hash_GetValue(entry);
320 
321 	/* create a head node if necessary. */
322 	if (head == NULL) {
323 		head = emalloc(sizeof(*head));
324 		head->head = SET;
325 		head->in_progress = RESET;
326 		head->fnode = NULL;
327 		head->sequence = 0;
328 		head->last = head->next = NULL;
329 		Hash_SetValue(entry, head);
330 	}
331 #if 0
332 	/*
333 	 * Don't warn about this.  We want to be able to support
334 	 * scripts that do two complex things:
335 	 *
336 	 *	- Two independent scripts which both provide the
337 	 *	  same thing.  Both scripts must be executed in
338 	 *	  any order to meet the barrier.  An example:
339 	 *
340 	 *		Script 1:
341 	 *
342 	 *			PROVIDE: mail
343 	 *			REQUIRE: LOGIN
344 	 *
345 	 *		Script 2:
346 	 *
347 	 *			PROVIDE: mail
348 	 *			REQUIRE: LOGIN
349 	 *
350 	 * 	- Two interdependent scripts which both provide the
351 	 *	  same thing.  Both scripts must be executed in
352 	 *	  graph order to meet the barrier.  An example:
353 	 *
354 	 *		Script 1:
355 	 *
356 	 *			PROVIDE: nameservice dnscache
357 	 *			REQUIRE: SERVERS
358 	 *
359 	 *		Script 2:
360 	 *
361 	 *			PROVIDE: nameservice nscd
362 	 *			REQUIRE: dnscache
363 	 */
364 	else if (new == 0) {
365 		warnx("file `%s' provides `%s'.", fnode->filename, s);
366 		warnx("\tpreviously seen in `%s'.",
367 		    head->next->fnode->filename);
368 	}
369 #endif
370 
371 	pnode = emalloc(sizeof(*pnode));
372 	pnode->head = RESET;
373 	pnode->in_progress = RESET;
374 	pnode->fnode = fnode;
375 	pnode->next = head->next;
376 	pnode->last = head;
377 	head->next = pnode;
378 	if (pnode->next != NULL)
379 		pnode->next->last = pnode;
380 
381 	f_pnode = emalloc(sizeof(*f_pnode));
382 	f_pnode->pnode = pnode;
383 	f_pnode->entry = entry;
384 	f_pnode->next = fnode->prov_list;
385 	fnode->prov_list = f_pnode;
386 }
387 
388 /*
389  * put the BEFORE: lines to a list and handle them later.
390  */
391 static void
392 add_before(filenode *fnode, char *s)
393 {
394 	strnodelist *bf_ent;
395 
396 	bf_ent = emalloc(sizeof *bf_ent + strlen(s));
397 	bf_ent->node = fnode;
398 	strcpy(bf_ent->s, s);
399 	bf_ent->next = bl_list;
400 	bl_list = bf_ent;
401 }
402 
403 /*
404  * add a key to a filenode.
405  */
406 static void
407 add_keyword(filenode *fnode, char *s)
408 {
409 
410 	strnode_add(&fnode->keyword_list, s, fnode);
411 }
412 
413 /*
414  * loop over the rest of a REQUIRE line, giving each word to
415  * add_require() to do the real work.
416  */
417 static void
418 parse_require(filenode *node, char *buffer)
419 {
420 	char *s;
421 
422 	while ((s = strsep(&buffer, " \t\n")) != NULL)
423 		if (*s != '\0')
424 			add_require(node, s);
425 }
426 
427 /*
428  * loop over the rest of a PROVIDE line, giving each word to
429  * add_provide() to do the real work.
430  */
431 static void
432 parse_provide(filenode *node, char *buffer)
433 {
434 	char *s;
435 
436 	while ((s = strsep(&buffer, " \t\n")) != NULL)
437 		if (*s != '\0')
438 			add_provide(node, s);
439 }
440 
441 /*
442  * loop over the rest of a BEFORE line, giving each word to
443  * add_before() to do the real work.
444  */
445 static void
446 parse_before(filenode *node, char *buffer)
447 {
448 	char *s;
449 
450 	while ((s = strsep(&buffer, " \t\n")) != NULL)
451 		if (*s != '\0')
452 			add_before(node, s);
453 }
454 
455 /*
456  * loop over the rest of a KEYWORD line, giving each word to
457  * add_keyword() to do the real work.
458  */
459 static void
460 parse_keywords(filenode *node, char *buffer)
461 {
462 	char *s;
463 
464 	while ((s = strsep(&buffer, " \t\n")) != NULL)
465 		if (*s != '\0')
466 			add_keyword(node, s);
467 }
468 
469 /*
470  * given a file name, create a filenode for it, read in lines looking
471  * for provision and requirement lines, building the graphs as needed.
472  */
473 static void
474 crunch_file(char *filename)
475 {
476 	FILE *fp;
477 	char *buf;
478 	int require_flag, provide_flag, before_flag, keywords_flag;
479 	enum { BEFORE_PARSING, PARSING, PARSING_DONE } state;
480 	filenode *node;
481 	char delims[3] = { '\\', '\\', '\0' };
482 	struct stat st;
483 
484 	if ((fp = fopen(filename, "r")) == NULL) {
485 		warn("could not open %s", filename);
486 		return;
487 	}
488 
489 	if (fstat(fileno(fp), &st) == -1) {
490 		warn("could not stat %s", filename);
491 		fclose(fp);
492 		return;
493 	}
494 
495 	if (!S_ISREG(st.st_mode)) {
496 #if 0
497 		warnx("%s is not a file", filename);
498 #endif
499 		fclose(fp);
500 		return;
501 	}
502 
503 	node = filenode_new(filename);
504 
505 	/*
506 	 * we don't care about length, line number, don't want # for comments,
507 	 * and have no flags.
508 	 */
509 	for (state = BEFORE_PARSING; state != PARSING_DONE &&
510 	    (buf = fparseln(fp, NULL, NULL, delims, 0)) != NULL; free(buf)) {
511 		require_flag = provide_flag = before_flag = keywords_flag = 0;
512 		if (strncmp(REQUIRE_STR, buf, REQUIRE_LEN) == 0)
513 			require_flag = REQUIRE_LEN;
514 		else if (strncmp(REQUIRES_STR, buf, REQUIRES_LEN) == 0)
515 			require_flag = REQUIRES_LEN;
516 		else if (strncmp(PROVIDE_STR, buf, PROVIDE_LEN) == 0)
517 			provide_flag = PROVIDE_LEN;
518 		else if (strncmp(PROVIDES_STR, buf, PROVIDES_LEN) == 0)
519 			provide_flag = PROVIDES_LEN;
520 		else if (strncmp(BEFORE_STR, buf, BEFORE_LEN) == 0)
521 			before_flag = BEFORE_LEN;
522 		else if (strncmp(KEYWORD_STR, buf, KEYWORD_LEN) == 0)
523 			keywords_flag = KEYWORD_LEN;
524 		else if (strncmp(KEYWORDS_STR, buf, KEYWORDS_LEN) == 0)
525 			keywords_flag = KEYWORDS_LEN;
526 		else {
527 			if (state == PARSING)
528 				state = PARSING_DONE;
529 			continue;
530 		}
531 
532 		state = PARSING;
533 		if (require_flag)
534 			parse_require(node, buf + require_flag);
535 		else if (provide_flag)
536 			parse_provide(node, buf + provide_flag);
537 		else if (before_flag)
538 			parse_before(node, buf + before_flag);
539 		else if (keywords_flag)
540 			parse_keywords(node, buf + keywords_flag);
541 	}
542 	fclose(fp);
543 }
544 
545 static Hash_Entry *
546 make_fake_provision(filenode *node)
547 {
548 	Hash_Entry *entry;
549 	f_provnode *f_pnode;
550 	provnode *head, *pnode;
551 	static	int i = 0;
552 	int	new;
553 	char buffer[30];
554 
555 	do {
556 		snprintf(buffer, sizeof buffer, FAKE_PROV_NAME "%08d", i++);
557 		entry = Hash_CreateEntry(provide_hash, buffer, &new);
558 	} while (new == 0);
559 	head = emalloc(sizeof(*head));
560 	head->head = SET;
561 	head->in_progress = RESET;
562 	head->fnode = NULL;
563 	head->last = head->next = NULL;
564 	Hash_SetValue(entry, head);
565 
566 	pnode = emalloc(sizeof(*pnode));
567 	pnode->head = RESET;
568 	pnode->in_progress = RESET;
569 	pnode->fnode = node;
570 	pnode->next = head->next;
571 	pnode->last = head;
572 	head->next = pnode;
573 	if (pnode->next != NULL)
574 		pnode->next->last = pnode;
575 
576 	f_pnode = emalloc(sizeof(*f_pnode));
577 	f_pnode->entry = entry;
578 	f_pnode->pnode = pnode;
579 	f_pnode->next = node->prov_list;
580 	node->prov_list = f_pnode;
581 
582 	return (entry);
583 }
584 
585 /*
586  * go through the BEFORE list, inserting requirements into the graph(s)
587  * as required.  in the before list, for each entry B, we have a file F
588  * and a string S.  we create a "fake" provision (P) that F provides.
589  * for each entry in the provision list for S, add a requirement to
590  * that provisions filenode for P.
591  */
592 static void
593 insert_before(void)
594 {
595 	Hash_Entry *entry, *fake_prov_entry;
596 	provnode *pnode;
597 	f_reqnode *rnode;
598 	strnodelist *bl;
599 	int new;
600 
601 	while (bl_list != NULL) {
602 		bl = bl_list->next;
603 
604 		fake_prov_entry = make_fake_provision(bl_list->node);
605 
606 		entry = Hash_CreateEntry(provide_hash, bl_list->s, &new);
607 		if (new == 1)
608 			warnx("file `%s' is before unknown provision `%s'", bl_list->node->filename, bl_list->s);
609 
610 		if (new == 1 && do_graphviz == true)
611 			generate_graphviz_file_links(
612 			    Hash_FindEntry(provide_hash, bl_list->s),
613 			    bl_list->node);
614 
615 		for (pnode = Hash_GetValue(entry); pnode; pnode = pnode->next) {
616 			if (pnode->head)
617 				continue;
618 
619 			rnode = emalloc(sizeof(*rnode));
620 			rnode->entry = fake_prov_entry;
621 			rnode->next = pnode->fnode->req_list;
622 			pnode->fnode->req_list = rnode;
623 		}
624 
625 		free(bl_list);
626 		bl_list = bl;
627 	}
628 }
629 
630 /*
631  * loop over all the files calling crunch_file() on them to do the
632  * real work.  after we have built all the nodes, insert the BEFORE:
633  * lines into graph(s).
634  */
635 static void
636 crunch_all_files(void)
637 {
638 	int i;
639 
640 	for (i = 0; i < file_count; i++)
641 		crunch_file(file_list[i]);
642 	insert_before();
643 }
644 
645 static inline int
646 is_fake_prov(const char *name)
647 {
648 
649 	return (name == strstr(name, FAKE_PROV_NAME));
650 }
651 
652 /* loop though provide list of vnode drawing all non-fake dependencies */
653 static void
654 generate_graphviz_file_links(Hash_Entry *entry, filenode *fnode)
655 {
656 	char *dep_name, *fname;
657 	provnode *head;
658 	f_provnode *fpnode, *rfpnode;
659 	int is_before = 0;
660 
661 	dep_name = Hash_GetKey(entry);
662 	if (is_fake_prov(dep_name))
663 		is_before = 1;
664 	head = Hash_GetValue(entry);
665 
666 	for (fpnode = fnode->prov_list; fpnode && fpnode->entry;
667 	    fpnode = fpnode->next) {
668 		fname = Hash_GetKey(fpnode->entry);
669 		if (is_fake_prov(fname))
670 			continue;
671 		rfpnode = NULL;
672 		do {
673 			if (rfpnode)
674 				dep_name = Hash_GetKey(rfpnode->entry);
675 			else
676 				dep_name = Hash_GetKey(entry);
677 
678 			if (!is_fake_prov(dep_name)) {
679 				printf("\"%s\" -> \"%s\" [%s%s];\n",
680 				    fname, dep_name,
681 				    /* edge style */
682 				    (is_before ? "style=dashed" : "style=solid"),
683 				    /* circular dep? */
684 				    ((head == NULL ||
685 				    (head->next && head->in_progress == SET)) ?
686 				    ", color=red, penwidth=4" : ""));
687 				if (rfpnode == NULL)
688 					break;
689 			}
690 			/* dependency is solved already */
691 			if (head == NULL || head->next == NULL)
692 				break;
693 
694 			if (rfpnode == NULL)
695 				rfpnode = head->next->fnode->prov_list;
696 			else
697 				rfpnode = rfpnode->next;
698 		} while (rfpnode);
699 	}
700 }
701 
702 /*
703  * Walk the stack, find the looping point and generate traceback.
704  * NULL is returned on failure, otherwize pointer to a buffer holding
705  * text representation is returned, caller must run free(3) for the
706  * pointer.
707  */
708 static char *
709 generate_loop_for_req(strnodelist *stack_tail, provnode *head,
710     filenode *fnode)
711 {
712 	provnode *pnode;
713 	strnodelist *stack_ptr, *loop_entry;
714 	char *buf, **revstack;
715 	size_t bufsize;
716 	int i, stack_depth;
717 
718 	loop_entry = NULL;
719 	/* fast forward stack to the component that is required now */
720 	for (pnode = head->next; pnode; pnode = pnode->next) {
721 		if (loop_entry)
722 			break;
723 		stack_depth = 0;
724 		for (stack_ptr = stack_tail; stack_ptr;
725 		    stack_ptr = stack_ptr->next) {
726 			stack_depth++;
727 			if (stack_ptr->node == pnode->fnode) {
728 				loop_entry = stack_ptr;
729 				break;
730 			}
731 		}
732 	}
733 
734 	if (loop_entry == NULL)
735 		return (NULL);
736 
737 	stack_depth += 2; /* fnode + loop_entry */
738 	revstack = emalloc(sizeof(char *) * stack_depth);
739 	bzero(revstack, (sizeof(char *) * stack_depth));
740 
741 	/* reverse stack and estimate buffer size to allocate */
742 	bufsize = 1; /* tralining \0 */
743 
744 	revstack[stack_depth - 1] = loop_entry->node->filename;
745 	bufsize += strlen(revstack[stack_depth - 1]);
746 
747 	revstack[stack_depth - 2] = fnode->filename;
748 	bufsize += strlen(revstack[stack_depth - 2]);
749 	fnode->issues_count++;
750 
751 	stack_ptr = stack_tail;
752 	for (i = stack_depth - 3; i >= 0; i--) {
753 		revstack[i] = stack_ptr->node->filename;
754 		stack_ptr->node->issues_count++;
755 		stack_ptr = stack_ptr->next;
756 		bufsize += strlen(revstack[i]);
757 	}
758 	bufsize += strlen(" -> ") * (stack_depth - 1);
759 
760 	buf = emalloc(bufsize);
761 	bzero(buf, bufsize);
762 
763 	for (i = 0; i < stack_depth; i++) {
764 		strlcat(buf, revstack[i], bufsize);
765 		if (i < stack_depth - 1)
766 			strlcat(buf, " -> ", bufsize);
767 	}
768 
769 	free(revstack);
770 	return (buf);
771 }
772 /*
773  * below are the functions that traverse the graphs we have built
774  * finding out the desired ordering, printing each file in turn.
775  * if missing requirements, or cyclic graphs are detected, a
776  * warning will be issued, and we will continue on..
777  */
778 
779 /*
780  * given a requirement node (in a filename) we attempt to satisfy it.
781  * we do some sanity checking first, to ensure that we have providers,
782  * aren't already satisfied and aren't already being satisfied (ie,
783  * cyclic).  if we pass all this, we loop over the provision list
784  * calling do_file() (enter recursion) for each filenode in this
785  * provision.
786  */
787 static void
788 satisfy_req(f_reqnode *rnode, filenode *fnode, strnodelist *stack_ptr)
789 {
790 	Hash_Entry *entry;
791 	provnode *head;
792 	strnodelist stack_item;
793 	char *buf;
794 
795 	entry = rnode->entry;
796 	head = Hash_GetValue(entry);
797 
798 	if (do_graphviz == true)
799 		generate_graphviz_file_links(entry, fnode);
800 
801 	if (head == NULL) {
802 		warnx("requirement `%s' in file `%s' has no providers.",
803 		    Hash_GetKey(entry), fnode->filename);
804 		exit_code = 1;
805 		return;
806 	}
807 
808 	/* return if the requirement is already satisfied. */
809 	if (head->next == NULL)
810 		return;
811 
812 	/*
813 	 * if list is marked as in progress,
814 	 *	print that there is a circular dependency on it and abort
815 	 */
816 	if (head->in_progress == SET) {
817 		exit_code = 1;
818 		buf = generate_loop_for_req(stack_ptr, head,
819 		    fnode);
820 
821 		if (buf == NULL) {
822 			warnx("Circular dependency on provision `%s' in "
823 			    "file `%s' (tracing has failed).",
824 			    Hash_GetKey(entry), fnode->filename);
825 			return;
826 		}
827 
828 		warnx("Circular dependency on provision `%s': %s.",
829 		    Hash_GetKey(entry), buf);
830 		free(buf);
831 		return;
832 	}
833 
834 	head->in_progress = SET;
835 
836 	stack_item.next = stack_ptr;
837 	stack_item.node = fnode;
838 
839 	/*
840 	 * while provision_list is not empty
841 	 *	do_file(first_member_of(provision_list));
842 	 */
843 	while (head->next != NULL)
844 		do_file(head->next->fnode, &stack_item);
845 }
846 
847 static int
848 skip_ok(filenode *fnode)
849 {
850 	strnodelist *s;
851 	strnodelist *k;
852 
853 	for (s = skip_list; s; s = s->next)
854 		for (k = fnode->keyword_list; k; k = k->next)
855 			if (strcmp(k->s, s->s) == 0)
856 				return (0);
857 
858 	return (1);
859 }
860 
861 static int
862 keep_ok(filenode *fnode)
863 {
864 	strnodelist *s;
865 	strnodelist *k;
866 
867 	for (s = keep_list; s; s = s->next)
868 		for (k = fnode->keyword_list; k; k = k->next)
869 			if (strcmp(k->s, s->s) == 0)
870 				return (1);
871 
872 	/* an empty keep_list means every one */
873 	return (!keep_list);
874 }
875 
876 /*
877  * given a filenode, we ensure we are not a cyclic graph.  if this
878  * is ok, we loop over the filenodes requirements, calling satisfy_req()
879  * for each of them.. once we have done this, remove this filenode
880  * from each provision table, as we are now done.
881  *
882  * NOTE: do_file() is called recursively from several places and cannot
883  * safely free() anything related to items that may be recursed on.
884  * Circular dependencies will cause problems if we do.
885  */
886 static void
887 do_file(filenode *fnode, strnodelist *stack_ptr)
888 {
889 	f_reqnode *r;
890 	f_provnode *p, *p_tmp;
891 	provnode *pnode, *head;
892 	int was_set;
893 	char *dep_name;
894 
895 	DPRINTF((stderr, "do_file on %s.\n", fnode->filename));
896 
897 	/*
898 	 * if fnode is marked as in progress,
899 	 *	 print that fnode; is circularly depended upon and abort.
900 	 */
901 	if (fnode->in_progress == SET) {
902 		warnx("Circular dependency on file `%s'.",
903 			fnode->filename);
904 		was_set = exit_code = 1;
905 	} else
906 		was_set = 0;
907 
908 	/* mark fnode */
909 	fnode->in_progress = SET;
910 
911 	/*
912 	 * for each requirement of fnode -> r
913 	 *	satisfy_req(r, filename)
914 	 */
915 	r = fnode->req_list;
916 	fnode->sequence = 0;
917 	while (r != NULL) {
918 		satisfy_req(r, fnode, stack_ptr);
919 		/* find sequence number where all requirements are satisfied */
920 		head = Hash_GetValue(r->entry);
921 		if (head && head->sequence > fnode->sequence)
922 			fnode->sequence = head->sequence;
923 		r = r->next;
924 	}
925 	fnode->req_list = NULL;
926 	fnode->sequence++;
927 
928 	/* if we've seen issues with this file - put it to the tail */
929 	if (fnode->issues_count)
930 		fnode->sequence = max_sequence + 1;
931 
932 	if (max_sequence < fnode->sequence)
933 		max_sequence = fnode->sequence;
934 
935 	/*
936 	 * for each provision of fnode -> p
937 	 *	remove fnode from provision list for p in hash table
938 	 */
939 	p = fnode->prov_list;
940 	while (p != NULL) {
941 		/* mark all troublemakers on graphviz */
942 		if (do_graphviz == true && fnode->issues_count) {
943 			dep_name = Hash_GetKey(p->entry);
944 			if (!is_fake_prov(dep_name))
945 				printf("\"%s\" [ color=red, penwidth=4 ];\n",
946 				    dep_name);
947 		}
948 
949 		/* update sequence when provided requirements are satisfied */
950 		head = Hash_GetValue(p->entry);
951 		if (head->sequence < fnode->sequence)
952 			head->sequence = fnode->sequence;
953 
954 		p_tmp = p;
955 		pnode = p->pnode;
956 		if (pnode->next != NULL) {
957 			pnode->next->last = pnode->last;
958 		}
959 		if (pnode->last != NULL) {
960 			pnode->last->next = pnode->next;
961 		}
962 		free(pnode);
963 		p = p->next;
964 		free(p_tmp);
965 	}
966 	fnode->prov_list = NULL;
967 
968 	/* do_it(fnode) */
969 	DPRINTF((stderr, "next do: "));
970 
971 	/* if we were already in progress, don't print again */
972 	if (do_graphviz != true && was_set == 0 && skip_ok(fnode) &&
973 	    keep_ok(fnode)) {
974 		*fn_seqlist = fnode;
975 		fn_seqlist++;
976 	}
977 
978 	if (fnode->next != NULL) {
979 		fnode->next->last = fnode->last;
980 	}
981 	if (fnode->last != NULL) {
982 		fnode->last->next = fnode->next;
983 	}
984 
985 	if (fnode->issues_count)
986 		warnx("`%s' was seen in circular dependencies for %d times.",
987 		    fnode->filename, fnode->issues_count);
988 
989 	DPRINTF((stderr, "nuking %s\n", fnode->filename));
990 }
991 
992 static void
993 generate_graphviz_header(void)
994 {
995 
996 	if (do_graphviz != true)
997 		return;
998 
999 	printf("digraph rcorder {\n"
1000 	    "rankdir=\"BT\";\n"
1001 	    "node [style=rounded, shape=record];\n"
1002 	    "graph [overlap = false];\n");
1003 }
1004 
1005 static void
1006 generate_graphviz_footer(void)
1007 {
1008 
1009 	if (do_graphviz == true)
1010 		printf("}\n");
1011 }
1012 
1013 static void
1014 generate_graphviz_providers(void)
1015 {
1016 	Hash_Entry *entry;
1017 	Hash_Search psearch;
1018 	provnode *head, *pnode;
1019 	char *dep_name;
1020 
1021 	if (do_graphviz != true)
1022 		return;
1023 
1024 	entry = Hash_EnumFirst(provide_hash, &psearch);
1025 	if (entry == NULL)
1026 		return;
1027 
1028 	do {
1029 		dep_name = Hash_GetKey(entry);
1030 		if (is_fake_prov(dep_name))
1031 			continue;
1032 		head = Hash_GetValue(entry);
1033 		/* no providers for this requirement */
1034 		if (head == NULL || head->next == NULL) {
1035 			printf("\"%s\" [label=\"{ %s | ENOENT }\", "
1036 			    "style=\"rounded,filled\", color=red];\n",
1037 			    dep_name, dep_name);
1038 			continue;
1039 		}
1040 		/* one PROVIDE word for one file that matches */
1041 		if (head->next->next == NULL &&
1042 		    strcmp(dep_name,
1043 		    basename(head->next->fnode->filename)) == 0) {
1044 		        continue;
1045 		}
1046 		printf("\"%s\" [label=\"{ %s | ", dep_name, dep_name);
1047 		for (pnode = head->next; pnode; pnode = pnode->next)
1048 			printf("%s\\n", basename(pnode->fnode->filename));
1049 
1050 		printf("}\"];\n");
1051 	} while (NULL != (entry = Hash_EnumNext(&psearch)));
1052 }
1053 
1054 static int
1055 sequence_cmp(const void *a, const void *b)
1056 {
1057 	const filenode *fna = *((const filenode * const *)a);
1058 	const filenode *fnb = *((const filenode * const *)b);
1059 	int left, right;
1060 
1061 	/* push phantom files to the end */
1062 	if (fna == NULL || fnb == NULL)
1063 		return ((fna < fnb) - (fna > fnb));
1064 
1065 	left =  fna->sequence;
1066 	right = fnb->sequence;
1067 
1068 	return ((left > right) - (left < right));
1069 }
1070 
1071 static void
1072 generate_ordering(void)
1073 {
1074 	filenode **seqlist, **psl;
1075 	int last_seq = 0;
1076 
1077 	/* Prepare order buffer, use an additional one as a list terminator */
1078 	seqlist = emalloc(sizeof(filenode *) * (file_count + 1));
1079 	bzero(seqlist, sizeof(filenode *) * (file_count + 1));
1080 	fn_seqlist = seqlist;
1081 
1082 	/*
1083 	 * while there remain undone files{f},
1084 	 *	pick an arbitrary f, and do_file(f)
1085 	 * Note that the first file in the file list is perfectly
1086 	 * arbitrary, and easy to find, so we use that.
1087 	 */
1088 
1089 	/*
1090 	 * N.B.: the file nodes "self delete" after they execute, so
1091 	 * after each iteration of the loop, the head will be pointing
1092 	 * to something totally different. The loop ends up being
1093 	 * executed only once for every strongly connected set of
1094 	 * nodes.
1095 	 */
1096 	while (fn_head->next != NULL) {
1097 		DPRINTF((stderr, "generate on %s\n", fn_head->next->filename));
1098 		do_file(fn_head->next, NULL);
1099 	}
1100 
1101 	/* Sort filenode list based on sequence */
1102 	qsort(seqlist, file_count, sizeof(filenode *), sequence_cmp);
1103 
1104 	for (psl = seqlist; *psl; psl++) {
1105 		printf("%s%s",
1106 		    (last_seq == 0 ? "" :
1107 		    (do_parallel != true || last_seq != (*psl)->sequence) ?
1108 		    "\n" : " "),
1109 		(*psl)->filename);
1110 		last_seq = (*psl)->sequence;
1111 		free((*psl)->filename);
1112 		free(*psl);
1113 	}
1114 	if (last_seq)
1115 		printf("\n");
1116 
1117 	free(seqlist);
1118 }
1119