getnetgrent.c revision 137675
1/* 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Rick Macklem at The University of Guelph. 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#if defined(LIBC_SCCS) && !defined(lint) 38static char sccsid[] = "@(#)getnetgrent.c 8.2 (Berkeley) 4/27/95"; 39#endif /* LIBC_SCCS and not lint */ 40#include <sys/cdefs.h> 41__FBSDID("$FreeBSD: head/lib/libc/gen/getnetgrent.c 137675 2004-11-13 20:40:32Z bz $"); 42 43#include <ctype.h> 44#include <stdio.h> 45#include <stdlib.h> 46#include <string.h> 47#include <unistd.h> 48 49#ifdef YP 50/* 51 * Notes: 52 * We want to be able to use NIS netgroups properly while retaining 53 * the ability to use a local /etc/netgroup file. Unfortunately, you 54 * can't really do both at the same time - at least, not efficiently. 55 * NetBSD deals with this problem by creating a netgroup database 56 * using Berkeley DB (just like the password database) that allows 57 * for lookups using netgroup, netgroup.byuser or netgroup.byhost 58 * searches. This is a neat idea, but I don't have time to implement 59 * something like that now. (I think ultimately it would be nice 60 * if we DB-fied the group and netgroup stuff all in one shot, but 61 * for now I'm satisfied just to have something that works well 62 * without requiring massive code changes.) 63 * 64 * Therefore, to still permit the use of the local file and maintain 65 * optimum NIS performance, we allow for the following conditions: 66 * 67 * - If /etc/netgroup does not exist and NIS is turned on, we use 68 * NIS netgroups only. 69 * 70 * - If /etc/netgroup exists but is empty, we use NIS netgroups 71 * only. 72 * 73 * - If /etc/netgroup exists and contains _only_ a '+', we use 74 * NIS netgroups only. 75 * 76 * - If /etc/netgroup exists, contains locally defined netgroups 77 * and a '+', we use a mixture of NIS and the local entries. 78 * This method should return the same NIS data as just using 79 * NIS alone, but it will be slower if the NIS netgroup database 80 * is large (innetgr() in particular will suffer since extra 81 * processing has to be done in order to determine memberships 82 * using just the raw netgroup data). 83 * 84 * - If /etc/netgroup exists and contains only locally defined 85 * netgroup entries, we use just those local entries and ignore 86 * NIS (this is the original, pre-NIS behavior). 87 */ 88 89#include <rpc/rpc.h> 90#include <rpcsvc/yp_prot.h> 91#include <rpcsvc/ypclnt.h> 92#include <sys/types.h> 93#include <sys/stat.h> 94#include <sys/param.h> 95#include <sys/errno.h> 96static char *_netgr_yp_domain; 97int _use_only_yp; 98static int _netgr_yp_enabled; 99static int _yp_innetgr; 100#endif 101 102#ifndef _PATH_NETGROUP 103#define _PATH_NETGROUP "/etc/netgroup" 104#endif 105 106/* 107 * Static Variables and functions used by setnetgrent(), getnetgrent() and 108 * endnetgrent(). 109 * There are two linked lists: 110 * - linelist is just used by setnetgrent() to parse the net group file via. 111 * parse_netgrp() 112 * - netgrp is the list of entries for the current netgroup 113 */ 114struct linelist { 115 struct linelist *l_next; /* Chain ptr. */ 116 int l_parsed; /* Flag for cycles */ 117 char *l_groupname; /* Name of netgroup */ 118 char *l_line; /* Netgroup entrie(s) to be parsed */ 119}; 120 121struct netgrp { 122 struct netgrp *ng_next; /* Chain ptr */ 123 char *ng_str[3]; /* Field pointers, see below */ 124}; 125#define NG_HOST 0 /* Host name */ 126#define NG_USER 1 /* User name */ 127#define NG_DOM 2 /* and Domain name */ 128 129static struct linelist *linehead = (struct linelist *)0; 130static struct netgrp *nextgrp = (struct netgrp *)0; 131static struct { 132 struct netgrp *gr; 133 char *grname; 134} grouphead = { 135 (struct netgrp *)0, 136 (char *)0, 137}; 138static FILE *netf = (FILE *)0; 139 140static int parse_netgrp(const char *); 141static struct linelist *read_for_group(const char *); 142void setnetgrent(const char *); 143void endnetgrent(void); 144int getnetgrent(char **, char **, char **); 145int innetgr(const char *, const char *, const char *, const char *); 146 147#define LINSIZ 1024 /* Length of netgroup file line */ 148 149/* 150 * setnetgrent() 151 * Parse the netgroup file looking for the netgroup and build the list 152 * of netgrp structures. Let parse_netgrp() and read_for_group() do 153 * most of the work. 154 */ 155void 156setnetgrent(const char *group) 157{ 158#ifdef YP 159 struct stat _yp_statp; 160 char _yp_plus; 161#endif 162 163 /* Sanity check */ 164 165 if (group == NULL || !strlen(group)) 166 return; 167 168 if (grouphead.gr == (struct netgrp *)0 || 169 strcmp(group, grouphead.grname)) { 170 endnetgrent(); 171#ifdef YP 172 /* Presumed guilty until proven innocent. */ 173 _use_only_yp = 0; 174 /* 175 * If /etc/netgroup doesn't exist or is empty, 176 * use NIS exclusively. 177 */ 178 if (((stat(_PATH_NETGROUP, &_yp_statp) < 0) && 179 errno == ENOENT) || _yp_statp.st_size == 0) 180 _use_only_yp = _netgr_yp_enabled = 1; 181 if ((netf = fopen(_PATH_NETGROUP,"r")) != NULL ||_use_only_yp){ 182 /* 183 * Icky: grab the first character of the netgroup file 184 * and turn on NIS if it's a '+'. rewind the stream 185 * afterwards so we don't goof up read_for_group() later. 186 */ 187 if (netf) { 188 fscanf(netf, "%c", &_yp_plus); 189 rewind(netf); 190 if (_yp_plus == '+') 191 _use_only_yp = _netgr_yp_enabled = 1; 192 } 193 /* 194 * If we were called specifically for an innetgr() 195 * lookup and we're in NIS-only mode, short-circuit 196 * parse_netgroup() and cut directly to the chase. 197 */ 198 if (_use_only_yp && _yp_innetgr) { 199 /* dohw! */ 200 if (netf != NULL) 201 fclose(netf); 202 return; 203 } 204#else 205 if ((netf = fopen(_PATH_NETGROUP, "r"))) { 206#endif 207 if (parse_netgrp(group)) 208 endnetgrent(); 209 else { 210 grouphead.grname = (char *) 211 malloc(strlen(group) + 1); 212 strcpy(grouphead.grname, group); 213 } 214 if (netf) 215 fclose(netf); 216 } 217 } 218 nextgrp = grouphead.gr; 219} 220 221/* 222 * Get the next netgroup off the list. 223 */ 224int 225getnetgrent(char **hostp, char **userp, char **domp) 226{ 227#ifdef YP 228 _yp_innetgr = 0; 229#endif 230 231 if (nextgrp) { 232 *hostp = nextgrp->ng_str[NG_HOST]; 233 *userp = nextgrp->ng_str[NG_USER]; 234 *domp = nextgrp->ng_str[NG_DOM]; 235 nextgrp = nextgrp->ng_next; 236 return (1); 237 } 238 return (0); 239} 240 241/* 242 * endnetgrent() - cleanup 243 */ 244void 245endnetgrent(void) 246{ 247 struct linelist *lp, *olp; 248 struct netgrp *gp, *ogp; 249 250 lp = linehead; 251 while (lp) { 252 olp = lp; 253 lp = lp->l_next; 254 free(olp->l_groupname); 255 free(olp->l_line); 256 free((char *)olp); 257 } 258 linehead = (struct linelist *)0; 259 if (grouphead.grname) { 260 free(grouphead.grname); 261 grouphead.grname = (char *)0; 262 } 263 gp = grouphead.gr; 264 while (gp) { 265 ogp = gp; 266 gp = gp->ng_next; 267 if (ogp->ng_str[NG_HOST]) 268 free(ogp->ng_str[NG_HOST]); 269 if (ogp->ng_str[NG_USER]) 270 free(ogp->ng_str[NG_USER]); 271 if (ogp->ng_str[NG_DOM]) 272 free(ogp->ng_str[NG_DOM]); 273 free((char *)ogp); 274 } 275 grouphead.gr = (struct netgrp *)0; 276#ifdef YP 277 _netgr_yp_enabled = 0; 278#endif 279} 280 281#ifdef YP 282static int 283_listmatch(const char *list, const char *group, int len) 284{ 285 const char *ptr = list; 286 const char *cptr; 287 int glen = strlen(group); 288 289 /* skip possible leading whitespace */ 290 while(isspace((unsigned char)*ptr)) 291 ptr++; 292 293 while (ptr < list + len) { 294 cptr = ptr; 295 while(*ptr != ',' && *ptr != '\0' && !isspace((unsigned char)*ptr)) 296 ptr++; 297 if (strncmp(cptr, group, glen) == 0 && glen == (ptr - cptr)) 298 return(1); 299 while(*ptr == ',' || isspace((unsigned char)*ptr)) 300 ptr++; 301 } 302 303 return(0); 304} 305 306static int 307_buildkey(char *key, const char *str, const char *dom, int *rotation) 308{ 309 (*rotation)++; 310 if (*rotation > 4) 311 return(0); 312 switch(*rotation) { 313 case(1): sprintf((char *)key, "%s.%s", str, dom ? dom : "*"); 314 break; 315 case(2): sprintf((char *)key, "%s.*", str); 316 break; 317 case(3): sprintf((char *)key, "*.%s", dom ? dom : "*"); 318 break; 319 case(4): sprintf((char *)key, "*.*"); 320 break; 321 } 322 return(1); 323} 324#endif 325 326/* 327 * Search for a match in a netgroup. 328 */ 329int 330innetgr(const char *group, const char *host, const char *user, const char *dom) 331{ 332 char *hst, *usr, *dm; 333#ifdef YP 334 char *result; 335 int resultlen; 336 int rv; 337#endif 338 /* Sanity check */ 339 340 if (group == NULL || !strlen(group)) 341 return (0); 342 343#ifdef YP 344 _yp_innetgr = 1; 345#endif 346 setnetgrent(group); 347#ifdef YP 348 _yp_innetgr = 0; 349 /* 350 * If we're in NIS-only mode, do the search using 351 * NIS 'reverse netgroup' lookups. 352 */ 353 if (_use_only_yp) { 354 char _key[MAXHOSTNAMELEN]; 355 int rot = 0, y = 0; 356 357 if(yp_get_default_domain(&_netgr_yp_domain)) 358 return(0); 359 while(_buildkey(_key, user ? user : host, dom, &rot)) { 360 y = yp_match(_netgr_yp_domain, user? "netgroup.byuser": 361 "netgroup.byhost", _key, strlen(_key), &result, 362 &resultlen); 363 if (y) { 364 /* 365 * If we get an error other than 'no 366 * such key in map' then something is 367 * wrong and we should stop the search. 368 */ 369 if (y != YPERR_KEY) 370 break; 371 } else { 372 rv = _listmatch(result, group, resultlen); 373 free(result); 374 if (rv) 375 return(1); 376 else 377 return(0); 378 } 379 } 380 /* 381 * Couldn't match using NIS-exclusive mode. If the error 382 * was YPERR_MAP, then the failure happened because there 383 * was no netgroup.byhost or netgroup.byuser map. The odds 384 * are we are talking to a Sun NIS+ server in YP emulation 385 * mode; if this is the case, then we have to do the check 386 * the 'old-fashioned' way by grovelling through the netgroup 387 * map and resolving memberships on the fly. 388 */ 389 if (y != YPERR_MAP) 390 return(0); 391 } 392 393 setnetgrent(group); 394#endif /* YP */ 395 396 while (getnetgrent(&hst, &usr, &dm)) 397 if ((host == NULL || hst == NULL || !strcmp(host, hst)) && 398 (user == NULL || usr == NULL || !strcmp(user, usr)) && 399 ( dom == NULL || dm == NULL || !strcmp(dom, dm))) { 400 endnetgrent(); 401 return (1); 402 } 403 endnetgrent(); 404 return (0); 405} 406 407/* 408 * Parse the netgroup file setting up the linked lists. 409 */ 410static int 411parse_netgrp(const char *group) 412{ 413 char *spos, *epos; 414 int len, strpos; 415#ifdef DEBUG 416 int fields; 417#endif 418 char *pos, *gpos; 419 struct netgrp *grp; 420 struct linelist *lp = linehead; 421 422 /* 423 * First, see if the line has already been read in. 424 */ 425 while (lp) { 426 if (!strcmp(group, lp->l_groupname)) 427 break; 428 lp = lp->l_next; 429 } 430 if (lp == (struct linelist *)0 && 431 (lp = read_for_group(group)) == (struct linelist *)0) 432 return (1); 433 if (lp->l_parsed) { 434#ifdef DEBUG 435 /* 436 * This error message is largely superflous since the 437 * code handles the error condition sucessfully, and 438 * spewing it out from inside libc can actually hose 439 * certain programs. 440 */ 441 fprintf(stderr, "Cycle in netgroup %s\n", lp->l_groupname); 442#endif 443 return (1); 444 } else 445 lp->l_parsed = 1; 446 pos = lp->l_line; 447 /* Watch for null pointer dereferences, dammit! */ 448 while (pos != NULL && *pos != '\0') { 449 if (*pos == '(') { 450 grp = (struct netgrp *)malloc(sizeof (struct netgrp)); 451 bzero((char *)grp, sizeof (struct netgrp)); 452 grp->ng_next = grouphead.gr; 453 grouphead.gr = grp; 454 pos++; 455 gpos = strsep(&pos, ")"); 456#ifdef DEBUG 457 fields = 0; 458#endif 459 for (strpos = 0; strpos < 3; strpos++) { 460 if ((spos = strsep(&gpos, ","))) { 461#ifdef DEBUG 462 fields++; 463#endif 464 while (*spos == ' ' || *spos == '\t') 465 spos++; 466 if ((epos = strpbrk(spos, " \t"))) { 467 *epos = '\0'; 468 len = epos - spos; 469 } else 470 len = strlen(spos); 471 if (len > 0) { 472 grp->ng_str[strpos] = (char *) 473 malloc(len + 1); 474 bcopy(spos, grp->ng_str[strpos], 475 len + 1); 476 } 477 } else { 478 /* 479 * All other systems I've tested 480 * return NULL for empty netgroup 481 * fields. It's up to user programs 482 * to handle the NULLs appropriately. 483 */ 484 grp->ng_str[strpos] = NULL; 485 } 486 } 487#ifdef DEBUG 488 /* 489 * Note: on other platforms, malformed netgroup 490 * entries are not normally flagged. While we 491 * can catch bad entries and report them, we should 492 * stay silent by default for compatibility's sake. 493 */ 494 if (fields < 3) 495 fprintf(stderr, "Bad entry (%s%s%s%s%s) in netgroup \"%s\"\n", 496 grp->ng_str[NG_HOST] == NULL ? "" : grp->ng_str[NG_HOST], 497 grp->ng_str[NG_USER] == NULL ? "" : ",", 498 grp->ng_str[NG_USER] == NULL ? "" : grp->ng_str[NG_USER], 499 grp->ng_str[NG_DOM] == NULL ? "" : ",", 500 grp->ng_str[NG_DOM] == NULL ? "" : grp->ng_str[NG_DOM], 501 lp->l_groupname); 502#endif 503 } else { 504 spos = strsep(&pos, ", \t"); 505 if (parse_netgrp(spos)) 506 continue; 507 } 508 if (pos == NULL) 509 break; 510 while (*pos == ' ' || *pos == ',' || *pos == '\t') 511 pos++; 512 } 513 return (0); 514} 515 516/* 517 * Read the netgroup file and save lines until the line for the netgroup 518 * is found. Return 1 if eof is encountered. 519 */ 520static struct linelist * 521read_for_group(const char *group) 522{ 523 char *pos, *spos, *linep, *olinep; 524 int len, olen; 525 int cont; 526 struct linelist *lp; 527 char line[LINSIZ + 2]; 528#ifdef YP 529 char *result; 530 int resultlen; 531 532 while (_netgr_yp_enabled || fgets(line, LINSIZ, netf) != NULL) { 533 if (_netgr_yp_enabled) { 534 if(!_netgr_yp_domain) 535 if(yp_get_default_domain(&_netgr_yp_domain)) 536 continue; 537 if (yp_match(_netgr_yp_domain, "netgroup", group, 538 strlen(group), &result, &resultlen)) { 539 free(result); 540 if (_use_only_yp) 541 return ((struct linelist *)0); 542 else { 543 _netgr_yp_enabled = 0; 544 continue; 545 } 546 } 547 snprintf(line, LINSIZ, "%s %s", group, result); 548 free(result); 549 } 550#else 551 while (fgets(line, LINSIZ, netf) != NULL) { 552#endif 553 pos = (char *)&line; 554#ifdef YP 555 if (*pos == '+') { 556 _netgr_yp_enabled = 1; 557 continue; 558 } 559#endif 560 if (*pos == '#') 561 continue; 562 while (*pos == ' ' || *pos == '\t') 563 pos++; 564 spos = pos; 565 while (*pos != ' ' && *pos != '\t' && *pos != '\n' && 566 *pos != '\0') 567 pos++; 568 len = pos - spos; 569 while (*pos == ' ' || *pos == '\t') 570 pos++; 571 if (*pos != '\n' && *pos != '\0') { 572 lp = (struct linelist *)malloc(sizeof (*lp)); 573 lp->l_parsed = 0; 574 lp->l_groupname = (char *)malloc(len + 1); 575 bcopy(spos, lp->l_groupname, len); 576 *(lp->l_groupname + len) = '\0'; 577 len = strlen(pos); 578 olen = 0; 579 580 /* 581 * Loop around handling line continuations. 582 */ 583 do { 584 if (*(pos + len - 1) == '\n') 585 len--; 586 if (*(pos + len - 1) == '\\') { 587 len--; 588 cont = 1; 589 } else 590 cont = 0; 591 if (len > 0) { 592 linep = (char *)malloc(olen + len + 1); 593 if (olen > 0) { 594 bcopy(olinep, linep, olen); 595 free(olinep); 596 } 597 bcopy(pos, linep + olen, len); 598 olen += len; 599 *(linep + olen) = '\0'; 600 olinep = linep; 601 } 602 if (cont) { 603 if (fgets(line, LINSIZ, netf)) { 604 pos = line; 605 len = strlen(pos); 606 } else 607 cont = 0; 608 } 609 } while (cont); 610 lp->l_line = linep; 611 lp->l_next = linehead; 612 linehead = lp; 613 614 /* 615 * If this is the one we wanted, we are done. 616 */ 617 if (!strcmp(lp->l_groupname, group)) 618 return (lp); 619 } 620 } 621#ifdef YP 622 /* 623 * Yucky. The recursive nature of this whole mess might require 624 * us to make more than one pass through the netgroup file. 625 * This might be best left outside the #ifdef YP, but YP is 626 * defined by default anyway, so I'll leave it like this 627 * until I know better. 628 */ 629 rewind(netf); 630#endif 631 return ((struct linelist *)0); 632} 633