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 33 #ifndef lint 34 static const char copyright[] = 35 "@(#) Copyright (c) 1989, 1993, 1994\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #ifndef lint 40 static const char sccsid[] = "@(#)tsort.c 8.3 (Berkeley) 5/4/95"; 41 #endif /* not lint */ 42 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 45 46 #include <sys/types.h> 47 48 #include <ctype.h> 49 #include <db.h> 50 #include <err.h> 51 #include <errno.h> 52 #include <fcntl.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 /* 59 * Topological sort. Input is a list of pairs of strings separated by 60 * white space (spaces, tabs, and/or newlines); strings are written to 61 * standard output in sorted order, one per line. 62 * 63 * usage: 64 * tsort [-dlq] [inputfile] 65 * If no input file is specified, standard input is read. 66 * 67 * Should be compatible with AT&T tsort HOWEVER the output is not identical 68 * (i.e. for most graphs there is more than one sorted order, and this tsort 69 * usually generates a different one then the AT&T tsort). Also, cycle 70 * reporting seems to be more accurate in this version (the AT&T tsort 71 * sometimes says a node is in a cycle when it isn't). 72 * 73 * Michael Rendell, michael@stretch.cs.mun.ca - Feb 26, '90 74 */ 75 76 #define NF_MARK 0x1 /* marker for cycle detection */ 77 #define NF_ACYCLIC 0x2 /* this node is cycle free */ 78 #define NF_NODEST 0x4 /* Unreachable */ 79 80 81 typedef struct node_str NODE; 82 83 struct node_str { 84 NODE **n_prevp; /* pointer to previous node's n_next */ 85 NODE *n_next; /* next node in graph */ 86 NODE **n_arcs; /* array of arcs to other nodes */ 87 int n_narcs; /* number of arcs in n_arcs[] */ 88 int n_arcsize; /* size of n_arcs[] array */ 89 int n_refcnt; /* # of arcs pointing to this node */ 90 int n_flags; /* NF_* */ 91 char n_name[1]; /* name of this node */ 92 }; 93 94 typedef struct _buf { 95 char *b_buf; 96 int b_bsize; 97 } BUF; 98 99 static DB *db; 100 static NODE *graph, **cycle_buf, **longest_cycle; 101 static int debug, longest, quiet; 102 103 static void add_arc(char *, char *); 104 static int find_cycle(NODE *, NODE *, int, int); 105 static NODE *get_node(char *); 106 static void *grow_buf(void *, size_t); 107 static void remove_node(NODE *); 108 static void clear_cycle(void); 109 static void tsort(void); 110 static void usage(void); 111 112 int 113 main(int argc, char *argv[]) 114 { 115 BUF *b; 116 int c, n; 117 FILE *fp; 118 int bsize, ch, nused; 119 BUF bufs[2]; 120 121 fp = NULL; 122 while ((ch = getopt(argc, argv, "dlq")) != -1) 123 switch (ch) { 124 case 'd': 125 debug = 1; 126 break; 127 case 'l': 128 longest = 1; 129 break; 130 case 'q': 131 quiet = 1; 132 break; 133 case '?': 134 default: 135 usage(); 136 } 137 argc -= optind; 138 argv += optind; 139 140 switch (argc) { 141 case 0: 142 fp = stdin; 143 break; 144 case 1: 145 if ((fp = fopen(*argv, "r")) == NULL) 146 err(1, "%s", *argv); 147 break; 148 default: 149 usage(); 150 } 151 152 for (b = bufs, n = 2; --n >= 0; b++) 153 b->b_buf = grow_buf(NULL, b->b_bsize = 1024); 154 155 /* parse input and build the graph */ 156 for (n = 0, c = getc(fp);;) { 157 while (c != EOF && isspace(c)) 158 c = getc(fp); 159 if (c == EOF) 160 break; 161 162 nused = 0; 163 b = &bufs[n]; 164 bsize = b->b_bsize; 165 do { 166 b->b_buf[nused++] = c; 167 if (nused == bsize) 168 b->b_buf = grow_buf(b->b_buf, bsize *= 2); 169 c = getc(fp); 170 } while (c != EOF && !isspace(c)); 171 172 b->b_buf[nused] = '\0'; 173 b->b_bsize = bsize; 174 if (n) 175 add_arc(bufs[0].b_buf, bufs[1].b_buf); 176 n = !n; 177 } 178 (void)fclose(fp); 179 if (n) 180 errx(1, "odd data count"); 181 182 /* do the sort */ 183 tsort(); 184 exit(0); 185 } 186 187 /* double the size of oldbuf and return a pointer to the new buffer. */ 188 static void * 189 grow_buf(void *bp, size_t size) 190 { 191 if ((bp = realloc(bp, size)) == NULL) 192 err(1, NULL); 193 return (bp); 194 } 195 196 /* 197 * add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in 198 * the graph, then add them. 199 */ 200 static void 201 add_arc(char *s1, char *s2) 202 { 203 NODE *n1; 204 NODE *n2; 205 int bsize, i; 206 207 n1 = get_node(s1); 208 209 if (!strcmp(s1, s2)) 210 return; 211 212 n2 = get_node(s2); 213 214 /* 215 * Check if this arc is already here. 216 */ 217 for (i = 0; i < n1->n_narcs; i++) 218 if (n1->n_arcs[i] == n2) 219 return; 220 /* 221 * Add it. 222 */ 223 if (n1->n_narcs == n1->n_arcsize) { 224 if (!n1->n_arcsize) 225 n1->n_arcsize = 10; 226 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2; 227 n1->n_arcs = grow_buf(n1->n_arcs, bsize); 228 n1->n_arcsize = bsize / sizeof(*n1->n_arcs); 229 } 230 n1->n_arcs[n1->n_narcs++] = n2; 231 ++n2->n_refcnt; 232 } 233 234 /* Find a node in the graph (insert if not found) and return a pointer to it. */ 235 static NODE * 236 get_node(char *name) 237 { 238 DBT data, key; 239 NODE *n; 240 241 if (db == NULL && 242 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL) 243 err(1, "db: %s", name); 244 245 key.data = name; 246 key.size = strlen(name) + 1; 247 248 switch ((*db->get)(db, &key, &data, 0)) { 249 case 0: 250 bcopy(data.data, &n, sizeof(n)); 251 return (n); 252 case 1: 253 break; 254 default: 255 case -1: 256 err(1, "db: %s", name); 257 } 258 259 if ((n = malloc(sizeof(NODE) + key.size)) == NULL) 260 err(1, NULL); 261 262 n->n_narcs = 0; 263 n->n_arcsize = 0; 264 n->n_arcs = NULL; 265 n->n_refcnt = 0; 266 n->n_flags = 0; 267 bcopy(name, n->n_name, key.size); 268 269 /* Add to linked list. */ 270 if ((n->n_next = graph) != NULL) 271 graph->n_prevp = &n->n_next; 272 n->n_prevp = &graph; 273 graph = n; 274 275 /* Add to hash table. */ 276 data.data = &n; 277 data.size = sizeof(n); 278 if ((*db->put)(db, &key, &data, 0)) 279 err(1, "db: %s", name); 280 return (n); 281 } 282 283 284 /* 285 * Clear the NODEST flag from all nodes. 286 */ 287 static void 288 clear_cycle(void) 289 { 290 NODE *n; 291 292 for (n = graph; n != NULL; n = n->n_next) 293 n->n_flags &= ~NF_NODEST; 294 } 295 296 /* do topological sort on graph */ 297 static void 298 tsort(void) 299 { 300 NODE *n, *next; 301 int cnt, i; 302 303 while (graph != NULL) { 304 /* 305 * Keep getting rid of simple cases until there are none left, 306 * if there are any nodes still in the graph, then there is 307 * a cycle in it. 308 */ 309 do { 310 for (cnt = 0, n = graph; n != NULL; n = next) { 311 next = n->n_next; 312 if (n->n_refcnt == 0) { 313 remove_node(n); 314 ++cnt; 315 } 316 } 317 } while (graph != NULL && cnt); 318 319 if (graph == NULL) 320 break; 321 322 if (!cycle_buf) { 323 /* 324 * Allocate space for two cycle logs - one to be used 325 * as scratch space, the other to save the longest 326 * cycle. 327 */ 328 for (cnt = 0, n = graph; n != NULL; n = n->n_next) 329 ++cnt; 330 cycle_buf = malloc(sizeof(NODE *) * cnt); 331 longest_cycle = malloc(sizeof(NODE *) * cnt); 332 if (cycle_buf == NULL || longest_cycle == NULL) 333 err(1, NULL); 334 } 335 for (n = graph; n != NULL; n = n->n_next) 336 if (!(n->n_flags & NF_ACYCLIC)) { 337 if ((cnt = find_cycle(n, n, 0, 0))) { 338 if (!quiet) { 339 warnx("cycle in data"); 340 for (i = 0; i < cnt; i++) 341 warnx("%s", 342 longest_cycle[i]->n_name); 343 } 344 remove_node(n); 345 clear_cycle(); 346 break; 347 } else { 348 /* to avoid further checks */ 349 n->n_flags |= NF_ACYCLIC; 350 clear_cycle(); 351 } 352 } 353 354 if (n == NULL) 355 errx(1, "internal error -- could not find cycle"); 356 } 357 } 358 359 /* print node and remove from graph (does not actually free node) */ 360 static void 361 remove_node(NODE *n) 362 { 363 NODE **np; 364 int i; 365 366 (void)printf("%s\n", n->n_name); 367 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++) 368 --(*np)->n_refcnt; 369 n->n_narcs = 0; 370 *n->n_prevp = n->n_next; 371 if (n->n_next) 372 n->n_next->n_prevp = n->n_prevp; 373 } 374 375 376 /* look for the longest? cycle from node from to node to. */ 377 static int 378 find_cycle(NODE *from, NODE *to, int longest_len, int depth) 379 { 380 NODE **np; 381 int i, len; 382 383 /* 384 * avoid infinite loops and ignore portions of the graph known 385 * to be acyclic 386 */ 387 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC)) 388 return (0); 389 from->n_flags |= NF_MARK; 390 391 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) { 392 cycle_buf[depth] = *np; 393 if (*np == to) { 394 if (depth + 1 > longest_len) { 395 longest_len = depth + 1; 396 (void)memcpy((char *)longest_cycle, 397 (char *)cycle_buf, 398 longest_len * sizeof(NODE *)); 399 } 400 } else { 401 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST)) 402 continue; 403 len = find_cycle(*np, to, longest_len, depth + 1); 404 405 if (debug) 406 (void)printf("%*s %s->%s %d\n", depth, "", 407 from->n_name, to->n_name, len); 408 409 if (len == 0) 410 (*np)->n_flags |= NF_NODEST; 411 412 if (len > longest_len) 413 longest_len = len; 414 415 if (len > 0 && !longest) 416 break; 417 } 418 } 419 from->n_flags &= ~NF_MARK; 420 return (longest_len); 421 } 422 423 static void 424 usage(void) 425 { 426 (void)fprintf(stderr, "usage: tsort [-dlq] [file]\n"); 427 exit(1); 428 } 429