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 1.2 2003/06/17 04:26:42 dillon 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 static int grscan(), start_gr();
  53 #ifdef YP
  54 #include <rpc/rpc.h>
  55 #include <rpcsvc/yp_prot.h>
  56 #include <rpcsvc/ypclnt.h>
  57 static int _gr_stepping_yp;
  58 static int _gr_yp_enabled;
  59 static int _getypgroup(struct group *, const char *, char *);
  60 static int _nextypgroup(struct group *);
  61 #endif
  62
  63 /* initial size for malloc and increase steps for realloc */
  64 #define MAXGRP          64
  65 #define MAXLINELENGTH   256
  66
  67 static char **members;          /* list of group members */
  68 static int maxgrp;              /* current length of **mebers */
  69 static char *line;              /* temp buffer for group line */
  70 static int maxlinelength;       /* current length of *line */
  71
  72 /*
  73  * Lines longer than MAXLINELENGTHLIMIT will be counted as an error.
  74  * <= 0 disable check for maximum line length
  75  * 256K is enough for 64,000 uids
  76  */
  77 #define MAXLINELENGTHLIMIT      (256 * 1024)
  78 #define GROUP_IGNORE_COMMENTS   1       /* allow comments in /etc/group */
  79
  80 struct group *
  81 getgrent()
  82 {
  83         if (!_gr_fp && !start_gr()) {
  84                 return NULL;
  85         }
  86
  87 #ifdef YP
  88         if (_gr_stepping_yp) {
  89                 if (_nextypgroup(&_gr_group))
  90                         return(&_gr_group);
  91         }
  92 tryagain:
  93 #endif
  94
  95         if (!grscan(0, 0, NULL))
  96                 return(NULL);
  97 #ifdef YP
  98         if(_gr_group.gr_name[0] == '+' && _gr_group.gr_name[1]) {
  99                 _getypgroup(&_gr_group, &_gr_group.gr_name[1],
 100                             "group.byname");
 101         } else if(_gr_group.gr_name[0] == '+') {
 102                 if (!_nextypgroup(&_gr_group))
 103                         goto tryagain;
 104                 else
 105                         return(&_gr_group);
 106         }
 107 #endif
 108         return(&_gr_group);
 109 }
 110
 111 struct group *
 112 getgrnam(name)
 113         const char *name;
 114 {
 115         int rval;
 116
 117         if (!start_gr())
 118                 return(NULL);
 119 #ifdef YP
 120         tryagain:
 121 #endif
 122         rval = grscan(1, 0, name);
 123 #ifdef YP
 124         if(rval == -1 && (_gr_yp_enabled < 0 || (_gr_yp_enabled &&
 125                                         _gr_group.gr_name[0] == '+'))) {
 126                 if (!(rval = _getypgroup(&_gr_group, name, "group.byname")))
 127                         goto tryagain;
 128         }
 129 #endif
 130         if (!_gr_stayopen)
 131                 endgrent();
 132         return (rval) ? &_gr_group : NULL;
 133 }
 134
 135 struct group *
 136 getgrgid(gid)
 137         gid_t gid;
 138 {
 139         int rval;
 140
 141         if (!start_gr())
 142                 return(NULL);
 143 #ifdef YP
 144         tryagain:
 145 #endif
 146         rval = grscan(1, gid, NULL);
 147 #ifdef YP
 148         if(rval == -1 && _gr_yp_enabled) {
 149                 char buf[16];
 150                 snprintf(buf, sizeof buf, "%d", (unsigned)gid);
 151                 if (!(rval = _getypgroup(&_gr_group, buf, "group.bygid")))
 152                         goto tryagain;
 153         }
 154 #endif
 155         if (!_gr_stayopen)
 156                 endgrent();
 157         return (rval) ? &_gr_group : NULL;
 158 }
 159
 160 static int
 161 start_gr()
 162 {
 163         if (_gr_fp) {
 164                 rewind(_gr_fp);
 165                 return(1);
 166         }
 167         _gr_fp = fopen(_PATH_GROUP, "r");
 168         if(!_gr_fp) return 0;
 169 #ifdef YP
 170         /*
 171          * This is a disgusting hack, used to determine when YP is enabled.
 172          * This would be easier if we had a group database to go along with
 173          * the password database.
 174          */
 175         {
 176                 char *line;
 177                 size_t linelen;
 178                 _gr_yp_enabled = 0;
 179                 while((line = fgetln(_gr_fp, &linelen)) != NULL) {
 180                         if(line[0] == '+') {
 181                                 if(line[1] && line[1] != ':' && !_gr_yp_enabled) {
 182                                         _gr_yp_enabled = 1;
 183                                 } else {
 184                                         _gr_yp_enabled = -1;
 185                                         break;
 186                                 }
 187                         }
 188                 }
 189                 rewind(_gr_fp);
 190         }
 191 #endif
 192
 193         if (maxlinelength == 0) {
 194                 if ((line = (char *)malloc(MAXLINELENGTH)) == NULL)
 195                         return 0;
 196                 maxlinelength += MAXLINELENGTH;
 197         }
 198
 199         if (maxgrp == 0) {
 200                 if ((members = (char **) malloc(sizeof(char **) *
 201                                                MAXGRP)) == NULL)
 202                         return 0;
 203                 maxgrp += MAXGRP;
 204         }
 205
 206         return 1;
 207 }
 208
 209 int
 210 setgrent(void)
 211 {
 212         return setgroupent(0);
 213 }
 214
 215 int
 216 setgroupent(stayopen)
 217         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()
 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(search, gid, name)
 242         register int search, gid;
 243         register char *name;
 244 {
 245         register char *cp, **m;
 246         char *bp;
 247
 248
 249 #ifdef YP
 250         int _ypfound;
 251 #endif
 252         for (;;) {
 253 #ifdef YP
 254                 _ypfound = 0;
 255 #endif
 256                 if (fgets(line, maxlinelength, _gr_fp) == NULL)
 257                         return(0);
 258
 259                 if (!index(line, '\n')) {
 260                         do {
 261                                 if (feof(_gr_fp))
 262                                         return(0);
 263
 264                                 /* don't allocate infinite memory */
 265                                 if (MAXLINELENGTHLIMIT > 0 &&
 266                                     maxlinelength >= MAXLINELENGTHLIMIT)
 267                                         return(0);
 268
 269                                 if ((line = (char *)reallocf(line,
 270                                      sizeof(char) *
 271                                      (maxlinelength + MAXLINELENGTH))) == NULL)
 272                                         return(0);
 273
 274                                 if (fgets(line + maxlinelength - 1,
 275                                           MAXLINELENGTH + 1, _gr_fp) == NULL)
 276                                         return(0);
 277
 278                                 maxlinelength += MAXLINELENGTH;
 279                         } while (!index(line + maxlinelength -
 280                                        MAXLINELENGTH - 1, '\n'));
 281                 }
 282
 283 #ifdef GROUP_IGNORE_COMMENTS
 284                 /*
 285                  * Ignore comments: ^[ \t]*#
 286                  */
 287                 for (cp = line; *cp != '\0'; cp++)
 288                         if (*cp != ' ' && *cp != '\t')
 289                                 break;
 290                 if (*cp == '#' || *cp == '\0')
 291                         continue;
 292 #endif
 293
 294                 bp = line;
 295
 296                 if ((_gr_group.gr_name = strsep(&bp, ":\n")) == NULL)
 297                         break;
 298 #ifdef YP
 299                 /*
 300                  * XXX   We need to be careful to avoid proceeding
 301                  * past this point under certain circumstances or
 302                  * we risk dereferencing null pointers down below.
 303                  */
 304                 if (_gr_group.gr_name[0] == '+') {
 305                         if (strlen(_gr_group.gr_name) == 1) {
 306                                 switch(search) {
 307                                 case 0:
 308                                         return(1);
 309                                 case 1:
 310                                         return(-1);
 311                                 default:
 312                                         return(0);
 313                                 }
 314                         } else {
 315                                 cp = &_gr_group.gr_name[1];
 316                                 if (search && name != NULL)
 317                                         if (strcmp(cp, name))
 318                                                 continue;
 319                                 if (!_getypgroup(&_gr_group, cp,
 320                                                 "group.byname"))
 321                                         continue;
 322                                 if (search && name == NULL)
 323                                         if (gid != _gr_group.gr_gid)
 324                                                 continue;
 325                         /* We're going to override -- tell the world. */
 326                                 _ypfound++;
 327                         }
 328                 }
 329 #else
 330                 if (_gr_group.gr_name[0] == '+')
 331                         continue;
 332 #endif /* YP */
 333                 if (search && name) {
 334                         if(strcmp(_gr_group.gr_name, name)) {
 335                                 continue;
 336                         }
 337                 }
 338 #ifdef YP
 339                 if ((cp = strsep(&bp, ":\n")) == NULL)
 340                         if (_ypfound)
 341                                 return(1);
 342                         else
 343                                 break;
 344                 if (strlen(cp) || !_ypfound)
 345                         _gr_group.gr_passwd = cp;
 346 #else
 347                 if ((_gr_group.gr_passwd = strsep(&bp, ":\n")) == NULL)
 348                         break;
 349 #endif
 350                 if (!(cp = strsep(&bp, ":\n")))
 351 #ifdef YP
 352                         if (_ypfound)
 353                                 return(1);
 354                         else
 355 #endif
 356                                 continue;
 357 #ifdef YP
 358                 /*
 359                  * Hurm. Should we be doing this? We allow UIDs to
 360                  * be overridden -- what about GIDs?
 361                  */
 362                 if (!_ypfound)
 363 #endif
 364                 _gr_group.gr_gid = atoi(cp);
 365                 if (search && name == NULL && _gr_group.gr_gid != gid)
 366                         continue;
 367                 cp = NULL;
 368                 if (bp == NULL) /* !!! Must check for this! */
 369                         break;
 370 #ifdef YP
 371                 if ((cp = strsep(&bp, ":\n")) == NULL)
 372                         break;
 373
 374                 if (!strlen(cp) && _ypfound)
 375                         return(1);
 376                 else
 377                         members[0] = NULL;
 378                 bp = cp;
 379                 cp = NULL;
 380 #endif
 381                 for (m = members; ; bp++) {
 382                         if (m == (members + maxgrp - 1)) {
 383                                 if ((members = (char **)
 384                                      reallocf(members,
 385                                              sizeof(char **) *
 386                                              (maxgrp + MAXGRP))) == NULL)
 387                                         return(0);
 388                                 m = members + maxgrp - 1;
 389                                 maxgrp += MAXGRP;
 390                         }
 391                         if (*bp == ',') {
 392                                 if (cp) {
 393                                         *bp = '\0';
 394                                         *m++ = cp;
 395                                         cp = NULL;
 396                                 }
 397                         } else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
 398                                 if (cp) {
 399                                         *bp = '\0';
 400                                         *m++ = cp;
 401                                 }
 402                                 break;
 403                         } else if (cp == NULL)
 404                                 cp = bp;
 405
 406                 }
 407                 _gr_group.gr_mem = members;
 408                 *m = NULL;
 409                 return(1);
 410         }
 411         /* NOTREACHED */
 412         return (0);
 413 }
 414
 415 #ifdef YP
 416
 417 static int
 418 _gr_breakout_yp(struct group *gr, char *result)
 419 {
 420         char *s, *cp;
 421         char **m;
 422
 423         /*
 424          * XXX If 's' ends up being a NULL pointer, punt on this group.
 425          * It means the NIS group entry is badly formatted and should
 426          * be skipped.
 427          */
 428         if ((s = strsep(&result, ":")) == NULL) return 0; /* name */
 429         gr->gr_name = s;
 430
 431         if ((s = strsep(&result, ":")) == NULL) return 0; /* password */
 432         gr->gr_passwd = s;
 433
 434         if ((s = strsep(&result, ":")) == NULL) return 0; /* gid */
 435         gr->gr_gid = atoi(s);
 436
 437         if ((s = result) == NULL) return 0;
 438         cp = 0;
 439
 440         for (m = members; ; s++) {
 441                 if (m == members + maxgrp - 1) {
 442                         if ((members = (char **)reallocf(members,
 443                              sizeof(char **) * (maxgrp + MAXGRP))) == NULL)
 444                                 return(0);
 445                         m = members + maxgrp - 1;
 446                         maxgrp += MAXGRP;
 447                 }
 448                 if (*s == ',') {
 449                         if (cp) {
 450                                 *s = '\0';
 451                                 *m++ = cp;
 452                                 cp = NULL;
 453                         }
 454                 } else if (*s == '\0' || *s == '\n' || *s == ' ') {
 455                         if (cp) {
 456                                 *s = '\0';
 457                                 *m++ = cp;
 458                         }
 459                         break;
 460                 } else if (cp == NULL) {
 461                         cp = s;
 462                 }
 463         }
 464         _gr_group.gr_mem = members;
 465         *m = NULL;
 466
 467         return 1;
 468 }
 469
 470 static char *_gr_yp_domain;
 471
 472 static int
 473 _getypgroup(struct group *gr, const char *name, char *map)
 474 {
 475         char *result, *s;
 476         static char resultbuf[YPMAXRECORD + 2];
 477         int resultlen;
 478
 479         if(!_gr_yp_domain) {
 480                 if(yp_get_default_domain(&_gr_yp_domain))
 481                   return 0;
 482         }
 483
 484         if(yp_match(_gr_yp_domain, map, name, strlen(name),
 485                     &result, &resultlen))
 486                 return 0;
 487
 488         s = strchr(result, '\n');
 489         if(s) *s = '\0';
 490
 491         if(resultlen >= sizeof resultbuf) return 0;
 492         strncpy(resultbuf, result, resultlen);
 493         resultbuf[resultlen] = '\0';
 494         free(result);
 495         return(_gr_breakout_yp(gr, resultbuf));
 496
 497 }
 498
 499
 500 static int
 501 _nextypgroup(struct group *gr)
 502 {
 503         static char *key;
 504         static int keylen;
 505         char *lastkey, *result;
 506         static char resultbuf[YPMAXRECORD + 2];
 507         int resultlen;
 508         int rv;
 509
 510         if(!_gr_yp_domain) {
 511                 if(yp_get_default_domain(&_gr_yp_domain))
 512                   return 0;
 513         }
 514
 515         if(!_gr_stepping_yp) {
 516                 if(key) free(key);
 517                 rv = yp_first(_gr_yp_domain, "group.byname",
 518                               &key, &keylen, &result, &resultlen);
 519                 if(rv) {
 520                         return 0;
 521                 }
 522                 _gr_stepping_yp = 1;
 523                 goto unpack;
 524         } else {
 525 tryagain:
 526                 lastkey = key;
 527                 rv = yp_next(_gr_yp_domain, "group.byname", key, keylen,
 528                              &key, &keylen, &result, &resultlen);
 529                 free(lastkey);
 530 unpack:
 531                 if(rv) {
 532                         _gr_stepping_yp = 0;
 533                         return 0;
 534                 }
 535
 536                 if(resultlen > sizeof(resultbuf)) {
 537                         free(result);
 538                         goto tryagain;
 539                 }
 540
 541                 strncpy(resultbuf, result, resultlen);
 542                 resultbuf[resultlen] = '\0';
 543                 free(result);
 544                 if((result = strchr(resultbuf, '\n')) != NULL)
 545                         *result = '\0';
 546                 if (_gr_breakout_yp(gr, resultbuf))
 547                         return(1);
 548                 else
 549                         goto tryagain;
 550         }
 551 }
 552
 553 #endif /* YP */