1 /* $NetBSD: tsort.c,v 1.23 2011/09/06 18:34:37 joerg Exp $ */ 2 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 #if HAVE_NBTOOL_CONFIG_H 36 #include "nbtool_config.h" 37 #endif 38 39 #include <sys/cdefs.h> 40 #if !defined(lint) 41 __COPYRIGHT("@(#) Copyright (c) 1989, 1993, 1994\ 42 The Regents of the University of California. All rights reserved."); 43 #if 0 44 static char sccsid[] = "@(#)tsort.c 8.3 (Berkeley) 5/4/95"; 45 #endif 46 __RCSID("$NetBSD: tsort.c,v 1.23 2011/09/06 18:34:37 joerg Exp $"); 47 #endif /* not lint */ 48 49 #include <sys/types.h> 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 [-l] [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 #define HASHSIZE 53 /* doesn't need to be big */ 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 typedef struct node_str NODE; 83 84 struct node_str { 85 NODE **n_prevp; /* pointer to previous node's n_next */ 86 NODE *n_next; /* next node in graph */ 87 NODE **n_arcs; /* array of arcs to other nodes */ 88 int n_narcs; /* number of arcs in n_arcs[] */ 89 int n_arcsize; /* size of n_arcs[] array */ 90 int n_refcnt; /* # of arcs pointing to this node */ 91 int n_flags; /* NF_* */ 92 char n_name[1]; /* name of this node */ 93 }; 94 95 typedef struct _buf { 96 char *b_buf; 97 int b_bsize; 98 } BUF; 99 100 static DB *db; 101 static NODE *graph, **cycle_buf, **longest_cycle; 102 static int debug, longest, quiet; 103 104 static void add_arc(char *, char *); 105 static void clear_cycle(void); 106 static int find_cycle(NODE *, NODE *, int, int); 107 static NODE *get_node(char *); 108 static void *grow_buf(void *, int); 109 static void remove_node(NODE *); 110 static void tsort(void); 111 __dead static void usage(void); 112 113 int 114 main(int argc, char *argv[]) 115 { 116 BUF *b; 117 int c, n; 118 FILE *fp; 119 int bsize, ch, nused; 120 BUF bufs[2]; 121 122 setprogname(argv[0]); 123 124 fp = NULL; 125 while ((ch = getopt(argc, argv, "dlq")) != -1) 126 switch (ch) { 127 case 'd': 128 debug = 1; 129 break; 130 case 'l': 131 longest = 1; 132 break; 133 case 'q': 134 quiet = 1; 135 break; 136 case '?': 137 default: 138 usage(); 139 } 140 argc -= optind; 141 argv += optind; 142 143 switch (argc) { 144 case 0: 145 fp = stdin; 146 break; 147 case 1: 148 if ((fp = fopen(*argv, "r")) == NULL) 149 err(1, "%s", *argv); 150 break; 151 default: 152 usage(); 153 } 154 155 for (b = bufs, n = 2; --n >= 0; b++) 156 b->b_buf = grow_buf(NULL, b->b_bsize = 1024); 157 158 /* parse input and build the graph */ 159 for (n = 0, c = getc(fp);;) { 160 while (c != EOF && isspace(c)) 161 c = getc(fp); 162 if (c == EOF) 163 break; 164 165 nused = 0; 166 b = &bufs[n]; 167 bsize = b->b_bsize; 168 do { 169 b->b_buf[nused++] = c; 170 if (nused == bsize) 171 b->b_buf = grow_buf(b->b_buf, bsize *= 2); 172 c = getc(fp); 173 } while (c != EOF && !isspace(c)); 174 175 b->b_buf[nused] = '\0'; 176 b->b_bsize = bsize; 177 if (n) 178 add_arc(bufs[0].b_buf, bufs[1].b_buf); 179 n = !n; 180 } 181 (void)fclose(fp); 182 if (n) 183 errx(1, "odd data count"); 184 185 /* do the sort */ 186 tsort(); 187 return(0); 188 } 189 190 /* double the size of oldbuf and return a pointer to the new buffer. */ 191 static void * 192 grow_buf(void *bp, int size) 193 { 194 void *n; 195 196 if ((n = realloc(bp, (u_int)size)) == NULL) 197 err(1, "realloc"); 198 bp = n; 199 return (bp); 200 } 201 202 /* 203 * add an arc from node s1 to node s2 in the graph. If s1 or s2 are not in 204 * the graph, then add them. 205 */ 206 static void 207 add_arc(char *s1, char *s2) 208 { 209 NODE *n1; 210 NODE *n2; 211 int bsize, i; 212 213 n1 = get_node(s1); 214 215 if (!strcmp(s1, s2)) 216 return; 217 218 n2 = get_node(s2); 219 220 /* 221 * Check if this arc is already here. 222 */ 223 for (i = 0; i < n1->n_narcs; i++) 224 if (n1->n_arcs[i] == n2) 225 return; 226 /* 227 * Add it. 228 */ 229 if (n1->n_narcs == n1->n_arcsize) { 230 if (!n1->n_arcsize) 231 n1->n_arcsize = 10; 232 bsize = n1->n_arcsize * sizeof(*n1->n_arcs) * 2; 233 n1->n_arcs = grow_buf(n1->n_arcs, bsize); 234 n1->n_arcsize = bsize / sizeof(*n1->n_arcs); 235 } 236 n1->n_arcs[n1->n_narcs++] = n2; 237 ++n2->n_refcnt; 238 } 239 240 /* Find a node in the graph (insert if not found) and return a pointer to it. */ 241 static NODE * 242 get_node(char *name) 243 { 244 DBT data, key; 245 NODE *n; 246 247 if (db == NULL && 248 (db = dbopen(NULL, O_RDWR, 0, DB_HASH, NULL)) == NULL) 249 err(1, "db: %s", name); 250 251 key.data = name; 252 key.size = strlen(name) + 1; 253 254 switch ((*db->get)(db, &key, &data, 0)) { 255 case 0: 256 (void)memmove(&n, data.data, sizeof(n)); 257 return (n); 258 case 1: 259 break; 260 default: 261 case -1: 262 err(1, "db: %s", name); 263 } 264 265 if ((n = malloc(sizeof(NODE) + key.size)) == NULL) 266 err(1, "malloc"); 267 268 n->n_narcs = 0; 269 n->n_arcsize = 0; 270 n->n_arcs = NULL; 271 n->n_refcnt = 0; 272 n->n_flags = 0; 273 (void)memmove(n->n_name, name, key.size); 274 275 /* Add to linked list. */ 276 if ((n->n_next = graph) != NULL) 277 graph->n_prevp = &n->n_next; 278 n->n_prevp = &graph; 279 graph = n; 280 281 /* Add to hash table. */ 282 data.data = &n; 283 data.size = sizeof(n); 284 if ((*db->put)(db, &key, &data, 0)) 285 err(1, "db: %s", name); 286 return (n); 287 } 288 289 290 /* 291 * Clear the NODEST flag from all nodes. 292 */ 293 static void 294 clear_cycle(void) 295 { 296 NODE *n; 297 298 for (n = graph; n != NULL; n = n->n_next) 299 n->n_flags &= ~NF_NODEST; 300 } 301 302 /* do topological sort on graph */ 303 static void 304 tsort(void) 305 { 306 NODE *n, *next; 307 int cnt, i; 308 309 while (graph != NULL) { 310 /* 311 * Keep getting rid of simple cases until there are none left, 312 * if there are any nodes still in the graph, then there is 313 * a cycle in it. 314 */ 315 do { 316 for (cnt = 0, n = graph; n != NULL; n = next) { 317 next = n->n_next; 318 if (n->n_refcnt == 0) { 319 remove_node(n); 320 ++cnt; 321 } 322 } 323 } while (graph != NULL && cnt); 324 325 if (graph == NULL) 326 break; 327 328 if (!cycle_buf) { 329 /* 330 * Allocate space for two cycle logs - one to be used 331 * as scratch space, the other to save the longest 332 * cycle. 333 */ 334 for (cnt = 0, n = graph; n != NULL; n = n->n_next) 335 ++cnt; 336 cycle_buf = malloc((u_int)sizeof(NODE *) * cnt); 337 longest_cycle = malloc((u_int)sizeof(NODE *) * cnt); 338 if (cycle_buf == NULL || longest_cycle == NULL) 339 err(1, "malloc"); 340 } 341 for (n = graph; n != NULL; n = n->n_next) { 342 if (!(n->n_flags & NF_ACYCLIC)) { 343 if ((cnt = find_cycle(n, n, 0, 0)) != 0) { 344 if (!quiet) { 345 warnx("cycle in data"); 346 for (i = 0; i < cnt; i++) 347 warnx("%s", 348 longest_cycle[i]->n_name); 349 } 350 remove_node(n); 351 clear_cycle(); 352 break; 353 } else { 354 /* to avoid further checks */ 355 n->n_flags |= NF_ACYCLIC; 356 clear_cycle(); 357 } 358 } 359 } 360 if (n == NULL) 361 errx(1, "internal error -- could not find cycle"); 362 } 363 } 364 365 /* print node and remove from graph (does not actually free node) */ 366 static void 367 remove_node(NODE *n) 368 { 369 NODE **np; 370 int i; 371 372 (void)printf("%s\n", n->n_name); 373 for (np = n->n_arcs, i = n->n_narcs; --i >= 0; np++) 374 --(*np)->n_refcnt; 375 n->n_narcs = 0; 376 *n->n_prevp = n->n_next; 377 if (n->n_next) 378 n->n_next->n_prevp = n->n_prevp; 379 } 380 381 382 /* look for the longest? cycle from node from to node to. */ 383 static int 384 find_cycle(NODE *from, NODE *to, int longest_len, int depth) 385 { 386 NODE **np; 387 int i, len; 388 389 /* 390 * avoid infinite loops and ignore portions of the graph known 391 * to be acyclic 392 */ 393 if (from->n_flags & (NF_NODEST|NF_MARK|NF_ACYCLIC)) 394 return (0); 395 from->n_flags |= NF_MARK; 396 397 for (np = from->n_arcs, i = from->n_narcs; --i >= 0; np++) { 398 cycle_buf[depth] = *np; 399 if (*np == to) { 400 if (depth + 1 > longest_len) { 401 longest_len = depth + 1; 402 (void)memcpy(longest_cycle, cycle_buf, 403 longest_len * sizeof(NODE *)); 404 } 405 } else { 406 if ((*np)->n_flags & (NF_MARK|NF_ACYCLIC|NF_NODEST)) 407 continue; 408 len = find_cycle(*np, to, longest_len, depth + 1); 409 410 if (debug) 411 (void)printf("%*s %s->%s %d\n", depth, "", 412 from->n_name, to->n_name, len); 413 414 if (len == 0) 415 (*np)->n_flags |= NF_NODEST; 416 417 if (len > longest_len) 418 longest_len = len; 419 420 if (len > 0 && !longest) 421 break; 422 } 423 } 424 from->n_flags &= ~NF_MARK; 425 return (longest_len); 426 } 427 428 static void 429 usage(void) 430 { 431 (void)fprintf(stderr, "usage: tsort [-lq] [file]\n"); 432 exit(1); 433 } 434