1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Michael Rendell of Memorial University of Newfoundland.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #ifndef lint
36 static const char copyright[] =
37 "@(#) Copyright (c) 1989, 1993, 1994\n\
38 The Regents of the University of California. All rights reserved.\n";
39 #endif /* not lint */
40
41 #ifndef lint
42 static const char sccsid[] = "@(#)tsort.c 8.3 (Berkeley) 5/4/95";
43 #endif /* not lint */
44
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD$");
47
48 #include <sys/types.h>
49
50 #include <ctype.h>
51 #include <db.h>
52 #include <err.h>
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59
60 /*
61 * Topological sort. Input is a list of pairs of strings separated by
62 * white space (spaces, tabs, and/or newlines); strings are written to
63 * standard output in sorted order, one per line.
64 *
65 * usage:
66 * tsort [-dlq] [inputfile]
67 * If no input file is specified, standard input is read.
68 *
69 * Should be compatible with AT&T tsort HOWEVER the output is not identical
70 * (i.e. for most graphs there is more than one sorted order, and this tsort
71 * usually generates a different one then the AT&T tsort). Also, cycle
72 * reporting seems to be more accurate in this version (the AT&T tsort
73 * sometimes says a node is in a cycle when it isn't).
74 *
75 * Michael Rendell, [email protected] - Feb 26, '90
76 */
77
78 #define NF_MARK 0x1 /* marker for cycle detection */
79 #define NF_ACYCLIC 0x2 /* this node is cycle free */
80 #define NF_NODEST 0x4 /* Unreachable */
81
82
83 typedef struct node_str NODE;
84
85 struct node_str {
86 NODE **n_prevp; /* pointer to previous node's n_next */
87 NODE *n_next; /* next node in graph */
88 NODE **n_arcs; /* array of arcs to other nodes */
89 int n_narcs; /* number of arcs in n_arcs[] */
90 int n_arcsize; /* size of n_arcs[] array */
91 int n_refcnt; /* # of arcs pointing to this node */
92 int n_flags; /* NF_* */
93 char n_name[1]; /* name of this node */
94 };
95
96 typedef struct _buf {
97 char *b_buf;
98 int b_bsize;
99 } BUF;
100
101 static DB *db;
102 static NODE *graph, **cycle_buf, **longest_cycle;
103 static int debug, longest, quiet;
104
105 static void add_arc(char *, char *);
106 static int find_cycle(NODE *, NODE *, int, int);
107 static NODE *get_node(char *);
108 static void *grow_buf(void *, size_t);
109 static void remove_node(NODE *);
110 static void clear_cycle(void);
111 static void tsort(void);
112 static void usage(void);
113
114 int
main(int argc,char * argv[])115 main(int argc, char *argv[])
116 {
117 BUF *b;
118 int c, n;
119 FILE *fp;
120 int bsize, ch, nused;
121 BUF bufs[2];
122
123 fp = NULL;
124 while ((ch = getopt(argc, argv, "dlq")) != -1)
125 switch (ch) {
126 case 'd':
127 debug = 1;
128 break;
129 case 'l':
130 longest = 1;
131 break;
132 case 'q':
133 quiet = 1;
134 break;
135 case '?':
136 default:
137 usage();
138 }
139 argc -= optind;
140 argv += optind;
141
142 switch (argc) {
143 case 0:
144 fp = stdin;
145 break;
146 case 1:
147 if ((fp = fopen(*argv, "r")) == NULL)
148 err(1, "%s", *argv);
149 break;
150 default:
151 usage();
152 }
153
154 for (b = bufs, n = 2; --n >= 0; b++)
155 b->b_buf = grow_buf(NULL, b->b_bsize = 1024);
156
157 /* parse input and build the graph */
158 for (n = 0, c = getc(fp);;) {
159 while (c != EOF && isspace(c))
160 c = getc(fp);
161 if (c == EOF)
162 break;
163
164 nused = 0;
165 b = &bufs[n];
166 bsize = b->b_bsize;
167 do {
168 b->b_buf[nused++] = c;
169 if (nused == bsize)
170 b->b_buf = grow_buf(b->b_buf, bsize *= 2);
171 c = getc(fp);
172 } while (c != EOF && !isspace(c));
173
174 b->b_buf[nused] = '\0';
175 b->b_bsize = bsize;
176 if (n)
177 add_arc(bufs[0].b_buf, bufs[1].b_buf);
178 n = !n;
179 }
180 (void)fclose(fp);
181 if (n)
182 errx(1, "odd data count");
183
184 /* do the sort */
185 tsort();
186 exit(0);
187 }
188
189 /* double the size of oldbuf and return a pointer to the new buffer. */
190 static void *
grow_buf(void * bp,size_t size)191 grow_buf(void *bp, size_t size)
192 {
193 if ((bp = realloc(bp, size)) == NULL)
194 err(1, NULL);
195 return (bp);
196 }
197
198 /*
199 * add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in
200 * the graph, then add them.
201 */
202 static void
add_arc(char * s1,char * s2)203 add_arc(char *s1, char *s2)
204 {
205 NODE *n1;
206 NODE *n2;
207 int bsize, i;
208
209 n1 = get_node(s1);
210
211 if (!strcmp(s1, s2))
212 return;
213
214 n2 = get_node(s2);
215
216 /*
217 * Check if this arc is already here.
218 */
219 for (i = 0; i < n1->n_narcs; i++)
220 if (n1->n_arcs[i] == n2)
221 return;
222 /*
223 * Add it.
224 */
225 if (n1->n_narcs == n1->n_arcsize) {
226 if (!n1->n_arcsize)
227 n1->n_arcsize = 10;
228 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2;
229 n1->n_arcs = grow_buf(n1->n_arcs, bsize);
230 n1->n_arcsize = bsize / sizeof(*n1->n_arcs);
231 }
232 n1->n_arcs[n1->n_narcs++] = n2;
233 ++n2->n_refcnt;
234 }
235
236 /* Find a node in the graph (insert if not found) and return a pointer to it. */
237 static NODE *
get_node(char * name)238 get_node(char *name)
239 {
240 DBT data, key;
241 NODE *n;
242
243 if (db == NULL &&
244 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL)
245 err(1, "db: %s", name);
246
247 key.data = name;
248 key.size = strlen(name) + 1;
249
250 switch ((*db->get)(db, &key, &data, 0)) {
251 case 0:
252 bcopy(data.data, &n, sizeof(n));
253 return (n);
254 case 1:
255 break;
256 default:
257 case -1:
258 err(1, "db: %s", name);
259 }
260
261 if ((n = malloc(sizeof(NODE) + key.size)) == NULL)
262 err(1, NULL);
263
264 n->n_narcs = 0;
265 n->n_arcsize = 0;
266 n->n_arcs = NULL;
267 n->n_refcnt = 0;
268 n->n_flags = 0;
269 bcopy(name, n->n_name, key.size);
270
271 /* Add to linked list. */
272 if ((n->n_next = graph) != NULL)
273 graph->n_prevp = &n->n_next;
274 n->n_prevp = &graph;
275 graph = n;
276
277 /* Add to hash table. */
278 data.data = &n;
279 data.size = sizeof(n);
280 if ((*db->put)(db, &key, &data, 0))
281 err(1, "db: %s", name);
282 return (n);
283 }
284
285
286 /*
287 * Clear the NODEST flag from all nodes.
288 */
289 static void
clear_cycle(void)290 clear_cycle(void)
291 {
292 NODE *n;
293
294 for (n = graph; n != NULL; n = n->n_next)
295 n->n_flags &= ~NF_NODEST;
296 }
297
298 /* do topological sort on graph */
299 static void
tsort(void)300 tsort(void)
301 {
302 NODE *n, *next;
303 int cnt, i;
304
305 while (graph != NULL) {
306 /*
307 * Keep getting rid of simple cases until there are none left,
308 * if there are any nodes still in the graph, then there is
309 * a cycle in it.
310 */
311 do {
312 for (cnt = 0, n = graph; n != NULL; n = next) {
313 next = n->n_next;
314 if (n->n_refcnt == 0) {
315 remove_node(n);
316 ++cnt;
317 }
318 }
319 } while (graph != NULL && cnt);
320
321 if (graph == NULL)
322 break;
323
324 if (!cycle_buf) {
325 /*
326 * Allocate space for two cycle logs - one to be used
327 * as scratch space, the other to save the longest
328 * cycle.
329 */
330 for (cnt = 0, n = graph; n != NULL; n = n->n_next)
331 ++cnt;
332 cycle_buf = malloc(sizeof(NODE *) * cnt);
333 longest_cycle = malloc(sizeof(NODE *) * cnt);
334 if (cycle_buf == NULL || longest_cycle == NULL)
335 err(1, NULL);
336 }
337 for (n = graph; n != NULL; n = n->n_next)
338 if (!(n->n_flags & NF_ACYCLIC)) {
339 if ((cnt = find_cycle(n, n, 0, 0))) {
340 if (!quiet) {
341 warnx("cycle in data");
342 for (i = 0; i < cnt; i++)
343 warnx("%s",
344 longest_cycle[i]->n_name);
345 }
346 remove_node(n);
347 clear_cycle();
348 break;
349 } else {
350 /* to avoid further checks */
351 n->n_flags |= NF_ACYCLIC;
352 clear_cycle();
353 }
354 }
355
356 if (n == NULL)
357 errx(1, "internal error -- could not find cycle");
358 }
359 }
360
361 /* print node and remove from graph (does not actually free node) */
362 static void
remove_node(NODE * n)363 remove_node(NODE *n)
364 {
365 NODE **np;
366 int i;
367
368 (void)printf("%s\n", n->n_name);
369 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++)
370 --(*np)->n_refcnt;
371 n->n_narcs = 0;
372 *n->n_prevp = n->n_next;
373 if (n->n_next)
374 n->n_next->n_prevp = n->n_prevp;
375 }
376
377
378 /* look for the longest? cycle from node from to node to. */
379 static int
find_cycle(NODE * from,NODE * to,int longest_len,int depth)380 find_cycle(NODE *from, NODE *to, int longest_len, int depth)
381 {
382 NODE **np;
383 int i, len;
384
385 /*
386 * avoid infinite loops and ignore portions of the graph known
387 * to be acyclic
388 */
389 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC))
390 return (0);
391 from->n_flags |= NF_MARK;
392
393 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) {
394 cycle_buf[depth] = *np;
395 if (*np == to) {
396 if (depth + 1 > longest_len) {
397 longest_len = depth + 1;
398 (void)memcpy((char *)longest_cycle,
399 (char *)cycle_buf,
400 longest_len * sizeof(NODE *));
401 }
402 } else {
403 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST))
404 continue;
405 len = find_cycle(*np, to, longest_len, depth + 1);
406
407 if (debug)
408 (void)printf("%*s %s->%s %d\n", depth, "",
409 from->n_name, to->n_name, len);
410
411 if (len == 0)
412 (*np)->n_flags |= NF_NODEST;
413
414 if (len > longest_len)
415 longest_len = len;
416
417 if (len > 0 && !longest)
418 break;
419 }
420 }
421 from->n_flags &= ~NF_MARK;
422 return (longest_len);
423 }
424
425 static void
usage(void)426 usage(void)
427 {
428 (void)fprintf(stderr, "usage: tsort [-dlq] [file]\n");
429 exit(1);
430 }
431