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