1 /* 2 * Copyright (c) 1989, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Michael Rendell of Memorial University of Newfoundland. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD: src/usr.bin/tsort/tsort.c,v 1.10.2.1 2001/03/04 09:18:23 kris Exp $ 33 * $DragonFly: src/usr.bin/tsort/tsort.c,v 1.4 2004/12/21 20:00:57 cpressey Exp $ 34 * 35 * @(#) Copyright (c) 1989, 1993, 1994 The Regents of the University of California. All rights reserved. 36 * @(#)tsort.c 8.3 (Berkeley) 5/4/95 37 */ 38 39 #include <sys/types.h> 40 41 #include <ctype.h> 42 #include <db.h> 43 #include <err.h> 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 51 /* 52 * Topological sort. Input is a list of pairs of strings separated by 53 * white space (spaces, tabs, and/or newlines); strings are written to 54 * standard output in sorted order, one per line. 55 * 56 * usage: 57 * tsort [-dlq] [inputfile] 58 * If no input file is specified, standard input is read. 59 * 60 * Should be compatible with AT&T tsort HOWEVER the output is not identical 61 * (i.e. for most graphs there is more than one sorted order, and this tsort 62 * usually generates a different one then the AT&T tsort). Also, cycle 63 * reporting seems to be more accurate in this version (the AT&T tsort 64 * sometimes says a node is in a cycle when it isn't). 65 * 66 * Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90 67 */ 68 #define HASHSIZE 53 /* doesn't need to be big */ 69 #define NF_MARK 0x1 /* marker for cycle detection */ 70 #define NF_ACYCLIC 0x2 /* this node is cycle free */ 71 #define NF_NODEST 0x4 /* Unreachable */ 72 73 74 typedef struct node_str NODE; 75 76 struct node_str { 77 NODE **n_prevp; /* pointer to previous node's n_next */ 78 NODE *n_next; /* next node in graph */ 79 NODE **n_arcs; /* array of arcs to other nodes */ 80 int n_narcs; /* number of arcs in n_arcs[] */ 81 int n_arcsize; /* size of n_arcs[] array */ 82 int n_refcnt; /* # of arcs pointing to this node */ 83 int n_flags; /* NF_* */ 84 char n_name[1]; /* name of this node */ 85 }; 86 87 typedef struct _buf { 88 char *b_buf; 89 size_t b_bsize; 90 } BUF; 91 92 DB *db; 93 NODE *graph, **cycle_buf, **longest_cycle; 94 int debug, longest, quiet; 95 96 static void add_arc(char *, char *); 97 static void clear_cycle(void); 98 static int find_cycle(NODE *, NODE *, int, int); 99 static NODE *get_node(char *); 100 static void *grow_buf(void *, size_t); 101 static void remove_node(NODE *); 102 static void tsort(void); 103 static void usage(void); 104 105 int 106 main(int argc, char **argv) 107 { 108 BUF *b; 109 int c, n; 110 FILE *fp; 111 int bsize, ch, nused; 112 BUF bufs[2]; 113 114 while ((ch = getopt(argc, argv, "dlq")) != -1) { 115 switch (ch) { 116 case 'd': 117 debug = 1; 118 break; 119 case 'l': 120 longest = 1; 121 break; 122 case 'q': 123 quiet = 1; 124 break; 125 case '?': 126 default: 127 usage(); 128 } 129 } 130 argc -= optind; 131 argv += optind; 132 133 fp = stdin; 134 switch (argc) { 135 case 0: 136 break; 137 case 1: 138 if ((fp = fopen(*argv, "r")) == NULL) 139 err(1, "%s", *argv); 140 break; 141 default: 142 usage(); 143 /* NOTREACHED */ 144 } 145 146 for (b = bufs, n = 2; --n >= 0; b++) 147 b->b_buf = grow_buf(NULL, b->b_bsize = 1024); 148 149 /* Parse input and build the graph. */ 150 for (n = 0, c = getc(fp);;) { 151 while (c != EOF && isspace(c)) 152 c = getc(fp); 153 if (c == EOF) 154 break; 155 156 nused = 0; 157 b = &bufs[n]; 158 bsize = b->b_bsize; 159 do { 160 b->b_buf[nused++] = c; 161 if (nused == bsize) 162 b->b_buf = grow_buf(b->b_buf, bsize *= 2); 163 c = getc(fp); 164 } while (c != EOF && !isspace(c)); 165 166 b->b_buf[nused] = '\0'; 167 b->b_bsize = bsize; 168 if (n) 169 add_arc(bufs[0].b_buf, bufs[1].b_buf); 170 n = !n; 171 } 172 fclose(fp); 173 if (n) 174 errx(1, "odd data count"); 175 176 /* Do the sort. */ 177 tsort(); 178 exit(0); 179 } 180 181 /* Double the size of oldbuf and return a pointer to the new buffer. */ 182 static void * 183 grow_buf(void *bp, size_t size) 184 { 185 if ((bp = realloc(bp, size)) == NULL) 186 err(1, NULL); 187 return (bp); 188 } 189 190 /* 191 * Add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in 192 * the graph, then add them. 193 */ 194 static void 195 add_arc(char *s1, char *s2) 196 { 197 NODE *n1; 198 NODE *n2; 199 int i; 200 size_t bsize; 201 202 n1 = get_node(s1); 203 204 if (strcmp(s1, s2) == 0) 205 return; 206 207 n2 = get_node(s2); 208 209 /* 210 * Check if this arc is already here. 211 */ 212 for (i = 0; i < n1->n_narcs; i++) 213 if (n1->n_arcs[i] == n2) 214 return; 215 /* 216 * Add it. 217 */ 218 if (n1->n_narcs == n1->n_arcsize) { 219 if (!n1->n_arcsize) 220 n1->n_arcsize = 10; 221 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2; 222 n1->n_arcs = grow_buf(n1->n_arcs, bsize); 223 n1->n_arcsize = bsize / sizeof(*n1->n_arcs); 224 } 225 n1->n_arcs[n1->n_narcs++] = n2; 226 ++n2->n_refcnt; 227 } 228 229 /* Find a node in the graph (insert if not found) and return a pointer to it. */ 230 static NODE * 231 get_node(char *name) 232 { 233 DBT data, key; 234 NODE *n; 235 236 if (db == NULL && 237 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL) 238 err(1, "db: %s", name); 239 240 key.data = name; 241 key.size = strlen(name) + 1; 242 243 switch ((*db->get)(db, &key, &data, 0)) { 244 case 0: 245 bcopy(data.data, &n, sizeof(n)); 246 return (n); 247 case 1: 248 break; 249 default: 250 case -1: 251 err(1, "db: %s", name); 252 } 253 254 if ((n = malloc(sizeof(NODE) + key.size)) == NULL) 255 err(1, NULL); 256 257 n->n_narcs = 0; 258 n->n_arcsize = 0; 259 n->n_arcs = NULL; 260 n->n_refcnt = 0; 261 n->n_flags = 0; 262 bcopy(name, n->n_name, key.size); 263 264 /* Add to linked list. */ 265 if ((n->n_next = graph) != NULL) 266 graph->n_prevp = &n->n_next; 267 n->n_prevp = &graph; 268 graph = n; 269 270 /* Add to hash table. */ 271 data.data = &n; 272 data.size = sizeof(n); 273 if ((*db->put)(db, &key, &data, 0)) 274 err(1, "db: %s", name); 275 return (n); 276 } 277 278 279 /* 280 * Clear the NODEST flag from all nodes. 281 */ 282 static void 283 clear_cycle(void) 284 { 285 NODE *n; 286 287 for (n = graph; n != NULL; n = n->n_next) 288 n->n_flags &= ~NF_NODEST; 289 } 290 291 /* Perform a topological sort of the graph. */ 292 static void 293 tsort(void) 294 { 295 NODE *n, *next; 296 int cnt, i; 297 298 while (graph != NULL) { 299 /* 300 * Keep getting rid of simple cases until there are none left, 301 * and if there are any nodes still in the graph, then there 302 * is a cycle in it. 303 */ 304 do { 305 for (cnt = 0, n = graph; n != NULL; n = next) { 306 next = n->n_next; 307 if (n->n_refcnt == 0) { 308 remove_node(n); 309 ++cnt; 310 } 311 } 312 } while (graph != NULL && cnt != 0); 313 314 if (graph == NULL) 315 break; 316 317 if (!cycle_buf) { 318 /* 319 * Allocate space for two cycle logs - one to be used 320 * as scratch space, the other to save the longest 321 * cycle. 322 */ 323 for (cnt = 0, n = graph; n != NULL; n = n->n_next) 324 ++cnt; 325 cycle_buf = malloc(sizeof(NODE *) * cnt); 326 longest_cycle = malloc(sizeof(NODE *) * cnt); 327 if (cycle_buf == NULL || longest_cycle == NULL) 328 err(1, NULL); 329 } 330 for (n = graph; n != NULL; n = n->n_next) 331 if (!(n->n_flags & NF_ACYCLIC)) { 332 if ((cnt = find_cycle(n, n, 0, 0))) { 333 if (!quiet) { 334 warnx("cycle in data"); 335 for (i = 0; i < cnt; i++) 336 warnx("%s", 337 longest_cycle[i]->n_name); 338 } 339 remove_node(n); 340 clear_cycle(); 341 break; 342 } else { 343 /* To avoid further checks: */ 344 n->n_flags |= NF_ACYCLIC; 345 clear_cycle(); 346 } 347 } 348 349 if (n == NULL) 350 errx(1, "internal error -- could not find cycle"); 351 } 352 } 353 354 /* 355 * Print a node and remove it from the graph (does not actually free 356 * the node.) 357 */ 358 static void 359 remove_node(NODE *n) 360 { 361 NODE **np; 362 int i; 363 364 printf("%s\n", n->n_name); 365 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++) 366 --(*np)->n_refcnt; 367 n->n_narcs = 0; 368 *n->n_prevp = n->n_next; 369 if (n->n_next != NULL) 370 n->n_next->n_prevp = n->n_prevp; 371 } 372 373 374 /* Look for the (longest?) cycle from node from to node to. */ 375 static int 376 find_cycle(NODE *from, NODE *to, int longest_len, int depth) 377 { 378 NODE **np; 379 int i, len; 380 381 /* 382 * Avoid infinite loops and ignore portions of the graph known 383 * to be acyclic. 384 */ 385 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC)) 386 return (0); 387 from->n_flags |= NF_MARK; 388 389 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) { 390 cycle_buf[depth] = *np; 391 if (*np == to) { 392 if (depth + 1 > longest_len) { 393 longest_len = depth + 1; 394 memcpy((char *)longest_cycle, 395 (char *)cycle_buf, 396 longest_len * sizeof(NODE *)); 397 } 398 } else { 399 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST)) 400 continue; 401 len = find_cycle(*np, to, longest_len, depth + 1); 402 403 if (debug) { 404 printf("%*s %s->%s %d\n", depth, "", 405 from->n_name, to->n_name, len); 406 } 407 408 if (len == 0) 409 (*np)->n_flags |= NF_NODEST; 410 411 if (len > longest_len) 412 longest_len = len; 413 414 if (len > 0 && !longest) 415 break; 416 } 417 } 418 from->n_flags &= ~NF_MARK; 419 return (longest_len); 420 } 421 422 static void 423 usage(void) 424 { 425 fprintf(stderr, "usage: tsort [-dlq] [file]\n"); 426 exit(1); 427 } 428