lib/libc/gen/getgrent.c

   1 /*      $NetBSD: getgrent.c,v 1.34.2.1 1999/04/27 14:10:58 perry Exp $  */
   2 /*
   3  * Copyright (c) 1989, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  * Portions Copyright (c) 1994, Jason Downs. All Rights Reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * @(#)getgrent.c       8.2 (Berkeley) 3/21/94
  36  * $FreeBSD: src/lib/libc/gen/getgrent.c,v 1.17.6.1 2001/03/05 08:56:02 obrien Exp $
  37  * $DragonFly: src/lib/libc/gen/getgrent.c,v 1.5 2005/11/19 22:32:53 swildner Exp $
  38  */
  39
  40 #include <errno.h>
  41 #include <limits.h>
  42 #include <sys/types.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <grp.h>
  47 #include <syslog.h>
  48
  49 static FILE *_gr_fp;
  50 static struct group _gr_group;
  51 static int _gr_stayopen;
  52
  53 static int      grscan(int, gid_t, const char *);
  54 static int      start_gr(void);
  55
  56 #ifdef YP
  57 #include <rpc/rpc.h>
  58 #include <rpcsvc/yp_prot.h>
  59 #include <rpcsvc/ypclnt.h>
  60 static int _gr_stepping_yp;
  61 static int _gr_yp_enabled;
  62 static int _getypgroup(struct group *, const char *, const char *);
  63 static int _nextypgroup(struct group *);
  64 #endif
  65
  66 /* initial size for malloc and increase steps for realloc */
  67 #define MAXGRP          64
  68 #define MAXLINELENGTH   256
  69
  70 static char **members;          /* list of group members */
  71 static int maxgrp;              /* current length of **mebers */
  72 static char *line;              /* temp buffer for group line */
  73 static int maxlinelength;       /* current length of *line */
  74
  75 /*
  76  * Lines longer than MAXLINELENGTHLIMIT will be counted as an error.
  77  * <= 0 disable check for maximum line length
  78  * 256K is enough for 64,000 uids
  79  */
  80 #define MAXLINELENGTHLIMIT      (256 * 1024)
  81 #define GROUP_IGNORE_COMMENTS   1       /* allow comments in /etc/group */
  82
  83 struct group *
  84 getgrent(void)
  85 {
  86         if (!_gr_fp && !start_gr()) {
  87                 return NULL;
  88         }
  89
  90 #ifdef YP
  91         if (_gr_stepping_yp) {
  92                 if (_nextypgroup(&_gr_group))
  93                         return(&_gr_group);
  94         }
  95 tryagain:
  96 #endif
  97
  98         if (!grscan(0, 0, NULL))
  99                 return(NULL);
 100 #ifdef YP
 101         if(_gr_group.gr_name[0] == '+' && _gr_group.gr_name[1]) {
 102                 _getypgroup(&_gr_group, &_gr_group.gr_name[1],
 103                             "group.byname");
 104         } else if(_gr_group.gr_name[0] == '+') {
 105                 if (!_nextypgroup(&_gr_group))
 106                         goto tryagain;
 107                 else
 108                         return(&_gr_group);
 109         }
 110 #endif
 111         return(&_gr_group);
 112 }
 113
 114 struct group *
 115 getgrnam(const char *name)
 116 {
 117         int rval;
 118
 119         if (!start_gr())
 120                 return(NULL);
 121 #ifdef YP
 122         tryagain:
 123 #endif
 124         rval = grscan(1, 0, name);
 125 #ifdef YP
 126         if(rval == -1 && (_gr_yp_enabled < 0 || (_gr_yp_enabled &&
 127                                         _gr_group.gr_name[0] == '+'))) {
 128                 if (!(rval = _getypgroup(&_gr_group, name, "group.byname")))
 129                         goto tryagain;
 130         }
 131 #endif
 132         if (!_gr_stayopen)
 133                 endgrent();
 134         return (rval) ? &_gr_group : NULL;
 135 }
 136
 137 struct group *
 138 getgrgid(gid_t gid)
 139 {
 140         int rval;
 141
 142         if (!start_gr())
 143                 return(NULL);
 144 #ifdef YP
 145         tryagain:
 146 #endif
 147         rval = grscan(1, gid, NULL);
 148 #ifdef YP
 149         if(rval == -1 && _gr_yp_enabled) {
 150                 char buf[16];
 151                 snprintf(buf, sizeof buf, "%d", (unsigned)gid);
 152                 if (!(rval = _getypgroup(&_gr_group, buf, "group.bygid")))
 153                         goto tryagain;
 154         }
 155 #endif
 156         if (!_gr_stayopen)
 157                 endgrent();
 158         return (rval) ? &_gr_group : NULL;
 159 }
 160
 161 static int
 162 start_gr(void)
 163 {
 164         if (_gr_fp) {
 165                 rewind(_gr_fp);
 166                 return(1);
 167         }
 168         _gr_fp = fopen(_PATH_GROUP, "r");
 169         if(!_gr_fp) return 0;
 170 #ifdef YP
 171         /*
 172          * This is a disgusting hack, used to determine when YP is enabled.
 173          * This would be easier if we had a group database to go along with
 174          * the password database.
 175          */
 176         {
 177                 char *my_line;
 178                 size_t linelen;
 179                 _gr_yp_enabled = 0;
 180                 while((my_line = fgetln(_gr_fp, &linelen)) != NULL) {
 181                         if(my_line[0] == '+') {
 182                                 if(my_line[1] && my_line[1] != ':' && !_gr_yp_enabled) {
 183                                         _gr_yp_enabled = 1;
 184                                 } else {
 185                                         _gr_yp_enabled = -1;
 186                                         break;
 187                                 }
 188                         }
 189                 }
 190                 rewind(_gr_fp);
 191         }
 192 #endif
 193
 194         if (maxlinelength == 0) {
 195                 if ((line = (char *)malloc(MAXLINELENGTH)) == NULL)
 196                         return 0;
 197                 maxlinelength += MAXLINELENGTH;
 198         }
 199
 200         if (maxgrp == 0) {
 201                 if ((members = (char **) malloc(sizeof(char **) *
 202                                                MAXGRP)) == NULL)
 203                         return 0;
 204                 maxgrp += MAXGRP;
 205         }
 206
 207         return 1;
 208 }
 209
 210 int
 211 setgrent(void)
 212 {
 213         return setgroupent(0);
 214 }
 215
 216 int
 217 setgroupent(int stayopen)
 218 {
 219         if (!start_gr())
 220                 return 0;
 221         _gr_stayopen = stayopen;
 222 #ifdef YP
 223         _gr_stepping_yp = 0;
 224 #endif
 225         return 1;
 226 }
 227
 228 void
 229 endgrent(void)
 230 {
 231 #ifdef YP
 232         _gr_stepping_yp = 0;
 233 #endif
 234         if (_gr_fp) {
 235                 (void)fclose(_gr_fp);
 236                 _gr_fp = NULL;
 237         }
 238 }
 239
 240 static int
 241 grscan(int search, gid_t gid, const char *name)
 242 {
 243         char *cp, **m;
 244         char *bp;
 245
 246
 247 #ifdef YP
 248         int _ypfound;
 249 #endif
 250         for (;;) {
 251 #ifdef YP
 252                 _ypfound = 0;
 253 #endif
 254                 if (fgets(line, maxlinelength, _gr_fp) == NULL)
 255                         return(0);
 256
 257                 if (!index(line, '\n')) {
 258                         do {
 259                                 if (feof(_gr_fp))
 260                                         return(0);
 261
 262                                 /* don't allocate infinite memory */
 263                                 if (MAXLINELENGTHLIMIT > 0 &&
 264                                     maxlinelength >= MAXLINELENGTHLIMIT)
 265                                         return(0);
 266
 267                                 if ((line = reallocf(line,
 268                                      (maxlinelength + MAXLINELENGTH))) == NULL)
 269                                         return(0);
 270
 271                                 if (fgets(line + maxlinelength - 1,
 272                                           MAXLINELENGTH + 1, _gr_fp) == NULL)
 273                                         return(0);
 274
 275                                 maxlinelength += MAXLINELENGTH;
 276                         } while (!index(line + maxlinelength -
 277                                        MAXLINELENGTH - 1, '\n'));
 278                 }
 279
 280 #ifdef GROUP_IGNORE_COMMENTS
 281                 /*
 282                  * Ignore comments: ^[ \t]*#
 283                  */
 284                 for (cp = line; *cp != '\0'; cp++)
 285                         if (*cp != ' ' && *cp != '\t')
 286                                 break;
 287                 if (*cp == '#' || *cp == '\0')
 288                         continue;
 289 #endif
 290
 291                 bp = line;
 292
 293                 if ((_gr_group.gr_name = strsep(&bp, ":\n")) == NULL)
 294                         break;
 295 #ifdef YP
 296                 /*
 297                  * XXX   We need to be careful to avoid proceeding
 298                  * past this point under certain circumstances or
 299                  * we risk dereferencing null pointers down below.
 300                  */
 301                 if (_gr_group.gr_name[0] == '+') {
 302                         if (strlen(_gr_group.gr_name) == 1) {
 303                                 switch(search) {
 304                                 case 0:
 305                                         return(1);
 306                                 case 1:
 307                                         return(-1);
 308                                 default:
 309                                         return(0);
 310                                 }
 311                         } else {
 312                                 cp = &_gr_group.gr_name[1];
 313                                 if (search && name != NULL)
 314                                         if (strcmp(cp, name))
 315                                                 continue;
 316                                 if (!_getypgroup(&_gr_group, cp,
 317                                                 "group.byname"))
 318                                         continue;
 319                                 if (search && name == NULL)
 320                                         if (gid != _gr_group.gr_gid)
 321                                                 continue;
 322                         /* We're going to override -- tell the world. */
 323                                 _ypfound++;
 324                         }
 325                 }
 326 #else
 327                 if (_gr_group.gr_name[0] == '+')
 328                         continue;
 329 #endif /* YP */
 330                 if (search && name) {
 331                         if(strcmp(_gr_group.gr_name, name)) {
 332                                 continue;
 333                         }
 334                 }
 335 #ifdef YP
 336                 if ((cp = strsep(&bp, ":\n")) == NULL) {
 337                         if (_ypfound)
 338                                 return(1);
 339                         else
 340                                 break;
 341                 }
 342                 if (strlen(cp) || !_ypfound)
 343                         _gr_group.gr_passwd = cp;
 344 #else
 345                 if ((_gr_group.gr_passwd = strsep(&bp, ":\n")) == NULL)
 346                         break;
 347 #endif
 348                 if (!(cp = strsep(&bp, ":\n"))) {
 349 #ifdef YP
 350                         if (_ypfound)
 351                                 return(1);
 352                         else
 353 #endif
 354                                 continue;
 355                 }
 356 #ifdef YP
 357                 /*
 358                  * Hurm. Should we be doing this? We allow UIDs to
 359                  * be overridden -- what about GIDs?
 360                  */
 361                 if (!_ypfound)
 362 #endif
 363                 _gr_group.gr_gid = atoi(cp);
 364                 if (search && name == NULL && _gr_group.gr_gid != gid)
 365                         continue;
 366                 cp = NULL;
 367                 if (bp == NULL) /* !!! Must check for this! */
 368                         break;
 369 #ifdef YP
 370                 if ((cp = strsep(&bp, ":\n")) == NULL)
 371                         break;
 372
 373                 if (!strlen(cp) && _ypfound)
 374                         return(1);
 375                 else
 376                         members[0] = NULL;
 377                 bp = cp;
 378                 cp = NULL;
 379 #endif
 380                 for (m = members; ; bp++) {
 381                         if (m == (members + maxgrp - 1)) {
 382                                 if ((members = (char **)
 383                                      reallocf(members,
 384                                              sizeof(char **) *
 385                                              (maxgrp + MAXGRP))) == NULL)
 386                                         return(0);
 387                                 m = members + maxgrp - 1;
 388                                 maxgrp += MAXGRP;
 389                         }
 390                         if (*bp == ',') {
 391                                 if (cp) {
 392                                         *bp = '\0';
 393                                         *m++ = cp;
 394                                         cp = NULL;
 395                                 }
 396                         } else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
 397                                 if (cp) {
 398                                         *bp = '\0';
 399                                         *m++ = cp;
 400                                 }
 401                                 break;
 402                         } else if (cp == NULL)
 403                                 cp = bp;
 404
 405                 }
 406                 _gr_group.gr_mem = members;
 407                 *m = NULL;
 408                 return(1);
 409         }
 410         /* NOTREACHED */
 411         return (0);
 412 }
 413
 414 #ifdef YP
 415
 416 static int
 417 _gr_breakout_yp(struct group *gr, char *result)
 418 {
 419         char *s, *cp;
 420         char **m;
 421
 422         /*
 423          * XXX If 's' ends up being a NULL pointer, punt on this group.
 424          * It means the NIS group entry is badly formatted and should
 425          * be skipped.
 426          */
 427         if ((s = strsep(&result, ":")) == NULL) return 0; /* name */
 428         gr->gr_name = s;
 429
 430         if ((s = strsep(&result, ":")) == NULL) return 0; /* password */
 431         gr->gr_passwd = s;
 432
 433         if ((s = strsep(&result, ":")) == NULL) return 0; /* gid */
 434         gr->gr_gid = atoi(s);
 435
 436         if ((s = result) == NULL) return 0;
 437         cp = 0;
 438
 439         for (m = members; ; s++) {
 440                 if (m == members + maxgrp - 1) {
 441                         if ((members = (char **)reallocf(members,
 442                              sizeof(char **) * (maxgrp + MAXGRP))) == NULL)
 443                                 return(0);
 444                         m = members + maxgrp - 1;
 445                         maxgrp += MAXGRP;
 446                 }
 447                 if (*s == ',') {
 448                         if (cp) {
 449                                 *s = '\0';
 450                                 *m++ = cp;
 451                                 cp = NULL;
 452                         }
 453                 } else if (*s == '\0' || *s == '\n' || *s == ' ') {
 454                         if (cp) {
 455                                 *s = '\0';
 456                                 *m++ = cp;
 457                         }
 458                         break;
 459                 } else if (cp == NULL) {
 460                         cp = s;
 461                 }
 462         }
 463         _gr_group.gr_mem = members;
 464         *m = NULL;
 465
 466         return 1;
 467 }
 468
 469 static char *_gr_yp_domain;
 470
 471 static int
 472 _getypgroup(struct group *gr, const char *name, const char *map)
 473 {
 474         char *result, *s;
 475         static char resultbuf[YPMAXRECORD + 2];
 476         int resultlen;
 477
 478         if(!_gr_yp_domain) {
 479                 if(yp_get_default_domain(&_gr_yp_domain))
 480                   return 0;
 481         }
 482
 483         if(yp_match(_gr_yp_domain, map, name, strlen(name),
 484                     &result, &resultlen))
 485                 return 0;
 486
 487         s = strchr(result, '\n');
 488         if(s) *s = '\0';
 489
 490         if (strlcpy(resultbuf, result, sizeof(resultbuf)) >= sizeof(resultbuf))
 491                 return(0);
 492         free(result);
 493         return(_gr_breakout_yp(gr, resultbuf));
 494
 495 }
 496
 497
 498 static int
 499 _nextypgroup(struct group *gr)
 500 {
 501         static char *key;
 502         static size_t keylen;
 503         char *lastkey, *result;
 504         static char resultbuf[YPMAXRECORD + 2];
 505         size_t resultlen;
 506         int rv;
 507
 508         if(!_gr_yp_domain) {
 509                 if(yp_get_default_domain(&_gr_yp_domain))
 510                   return 0;
 511         }
 512
 513         if(!_gr_stepping_yp) {
 514                 if(key) free(key);
 515                 rv = yp_first(_gr_yp_domain, "group.byname",
 516                               &key, &keylen, &result, &resultlen);
 517                 if(rv) {
 518                         return 0;
 519                 }
 520                 _gr_stepping_yp = 1;
 521                 goto unpack;
 522         } else {
 523 tryagain:
 524                 lastkey = key;
 525                 rv = yp_next(_gr_yp_domain, "group.byname", key, keylen,
 526                              &key, &keylen, &result, &resultlen);
 527                 free(lastkey);
 528 unpack:
 529                 if(rv) {
 530                         _gr_stepping_yp = 0;
 531                         return 0;
 532                 }
 533
 534                 if(resultlen > sizeof(resultbuf)) {
 535                         free(result);
 536                         goto tryagain;
 537                 }
 538
 539                 strncpy(resultbuf, result, resultlen);
 540                 resultbuf[resultlen] = '\0';
 541                 free(result);
 542                 if((result = strchr(resultbuf, '\n')) != NULL)
 543                         *result = '\0';
 544                 if (_gr_breakout_yp(gr, resultbuf))
 545                         return(1);
 546                 else
 547                         goto tryagain;
 548         }
 549 }
 550
 551 #endif /* YP */