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, michael@stretch.cs.mun.ca - 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 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 if (ferror(stdout) != 0 || fflush(stdout) != 0) 187 err(1, "stdout"); 188 exit(0); 189 } 190 191 /* double the size of oldbuf and return a pointer to the new buffer. */ 192 static void * 193 grow_buf(void *bp, size_t size) 194 { 195 if ((bp = realloc(bp, size)) == NULL) 196 err(1, NULL); 197 return (bp); 198 } 199 200 /* 201 * add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in 202 * the graph, then add them. 203 */ 204 static void 205 add_arc(char *s1, char *s2) 206 { 207 NODE *n1; 208 NODE *n2; 209 int bsize, i; 210 211 n1 = get_node(s1); 212 213 if (!strcmp(s1, s2)) 214 return; 215 216 n2 = get_node(s2); 217 218 /* 219 * Check if this arc is already here. 220 */ 221 for (i = 0; i < n1->n_narcs; i++) 222 if (n1->n_arcs[i] == n2) 223 return; 224 /* 225 * Add it. 226 */ 227 if (n1->n_narcs == n1->n_arcsize) { 228 if (!n1->n_arcsize) 229 n1->n_arcsize = 10; 230 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2; 231 n1->n_arcs = grow_buf(n1->n_arcs, bsize); 232 n1->n_arcsize = bsize / sizeof(*n1->n_arcs); 233 } 234 n1->n_arcs[n1->n_narcs++] = n2; 235 ++n2->n_refcnt; 236 } 237 238 /* Find a node in the graph (insert if not found) and return a pointer to it. */ 239 static NODE * 240 get_node(char *name) 241 { 242 DBT data, key; 243 NODE *n; 244 245 if (db == NULL && 246 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL) 247 err(1, "db: %s", name); 248 249 key.data = name; 250 key.size = strlen(name) + 1; 251 252 switch ((*db->get)(db, &key, &data, 0)) { 253 case 0: 254 memcpy(&n, data.data, sizeof(n)); 255 return (n); 256 case 1: 257 break; 258 default: 259 case -1: 260 err(1, "db: %s", name); 261 } 262 263 if ((n = malloc(sizeof(NODE) + key.size)) == NULL) 264 err(1, NULL); 265 266 n->n_narcs = 0; 267 n->n_arcsize = 0; 268 n->n_arcs = NULL; 269 n->n_refcnt = 0; 270 n->n_flags = 0; 271 memcpy(n->n_name, name, key.size); 272 273 /* Add to linked list. */ 274 if ((n->n_next = graph) != NULL) 275 graph->n_prevp = &n->n_next; 276 n->n_prevp = &graph; 277 graph = n; 278 279 /* Add to hash table. */ 280 data.data = &n; 281 data.size = sizeof(n); 282 if ((*db->put)(db, &key, &data, 0)) 283 err(1, "db: %s", name); 284 return (n); 285 } 286 287 288 /* 289 * Clear the NODEST flag from all nodes. 290 */ 291 static void 292 clear_cycle(void) 293 { 294 NODE *n; 295 296 for (n = graph; n != NULL; n = n->n_next) 297 n->n_flags &= ~NF_NODEST; 298 } 299 300 /* do topological sort on graph */ 301 static void 302 tsort(void) 303 { 304 NODE *n, *next; 305 int cnt, i; 306 307 while (graph != NULL) { 308 /* 309 * Keep getting rid of simple cases until there are none left, 310 * if there are any nodes still in the graph, then there is 311 * a cycle in it. 312 */ 313 do { 314 for (cnt = 0, n = graph; n != NULL; n = next) { 315 next = n->n_next; 316 if (n->n_refcnt == 0) { 317 remove_node(n); 318 ++cnt; 319 } 320 } 321 } while (graph != NULL && cnt); 322 323 if (graph == NULL) 324 break; 325 326 if (!cycle_buf) { 327 /* 328 * Allocate space for two cycle logs - one to be used 329 * as scratch space, the other to save the longest 330 * cycle. 331 */ 332 for (cnt = 0, n = graph; n != NULL; n = n->n_next) 333 ++cnt; 334 cycle_buf = malloc(sizeof(NODE *) * cnt); 335 longest_cycle = malloc(sizeof(NODE *) * cnt); 336 if (cycle_buf == NULL || longest_cycle == NULL) 337 err(1, NULL); 338 } 339 for (n = graph; n != NULL; n = n->n_next) 340 if (!(n->n_flags & NF_ACYCLIC)) { 341 if ((cnt = find_cycle(n, n, 0, 0))) { 342 if (!quiet) { 343 warnx("cycle in data"); 344 for (i = 0; i < cnt; i++) 345 warnx("%s", 346 longest_cycle[i]->n_name); 347 } 348 remove_node(n); 349 clear_cycle(); 350 break; 351 } else { 352 /* to avoid further checks */ 353 n->n_flags |= NF_ACYCLIC; 354 clear_cycle(); 355 } 356 } 357 358 if (n == NULL) 359 errx(1, "internal error -- could not find cycle"); 360 } 361 } 362 363 /* print node and remove from graph (does not actually free node) */ 364 static void 365 remove_node(NODE *n) 366 { 367 NODE **np; 368 int i; 369 370 (void)printf("%s\n", n->n_name); 371 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++) 372 --(*np)->n_refcnt; 373 n->n_narcs = 0; 374 *n->n_prevp = n->n_next; 375 if (n->n_next) 376 n->n_next->n_prevp = n->n_prevp; 377 } 378 379 380 /* look for the longest? cycle from node from to node to. */ 381 static int 382 find_cycle(NODE *from, NODE *to, int longest_len, int depth) 383 { 384 NODE **np; 385 int i, len; 386 387 /* 388 * avoid infinite loops and ignore portions of the graph known 389 * to be acyclic 390 */ 391 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC)) 392 return (0); 393 from->n_flags |= NF_MARK; 394 395 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) { 396 cycle_buf[depth] = *np; 397 if (*np == to) { 398 if (depth + 1 > longest_len) { 399 longest_len = depth + 1; 400 (void)memcpy((char *)longest_cycle, 401 (char *)cycle_buf, 402 longest_len * sizeof(NODE *)); 403 } 404 } else { 405 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST)) 406 continue; 407 len = find_cycle(*np, to, longest_len, depth + 1); 408 409 if (debug) 410 (void)printf("%*s %s->%s %d\n", depth, "", 411 from->n_name, to->n_name, len); 412 413 if (len == 0) 414 (*np)->n_flags |= NF_NODEST; 415 416 if (len > longest_len) 417 longest_len = len; 418 419 if (len > 0 && !longest) 420 break; 421 } 422 } 423 from->n_flags &= ~NF_MARK; 424 return (longest_len); 425 } 426 427 static void 428 usage(void) 429 { 430 (void)fprintf(stderr, "usage: tsort [-dlq] [file]\n"); 431 exit(1); 432 } 433