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