nis/nss_compat/compat-grp.c

   1 /* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1996.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <nss.h>
  23 #include <grp.h>
  24 #include <ctype.h>
  25 #include <bits/libc-lock.h>
  26 #include <string.h>
  27 #include <rpcsvc/yp.h>
  28 #include <rpcsvc/ypclnt.h>
  29 #include <rpcsvc/nis.h>
  30 #include <nsswitch.h>
  31
  32 #include "nss-nisplus.h"
  33 #include "nisplus-parser.h"
  34
  35 static service_user *ni = NULL;
  36 static bool_t use_nisplus = FALSE; /* default: group_compat: nis */
  37 static nis_name grptable = NULL; /* Name of the group table */
  38 static size_t grptablelen = 0;
  39
  40 /* Get the declaration of the parser function.  */
  41 #define ENTNAME grent
  42 #define STRUCTURE group
  43 #define EXTERN_PARSER
  44 #include <nss/nss_files/files-parse.c>
  45
  46 /* Structure for remembering -group members ... */
  47 #define BLACKLIST_INITIAL_SIZE 512
  48 #define BLACKLIST_INCREMENT 256
  49 struct blacklist_t
  50   {
  51     char *data;
  52     int current;
  53     int size;
  54   };
  55
  56 struct ent_t
  57   {
  58     bool_t nis;
  59     bool_t nis_first;
  60     char *oldkey;
  61     int oldkeylen;
  62     nis_result *result;
  63     FILE *stream;
  64     struct blacklist_t blacklist;
  65 };
  66 typedef struct ent_t ent_t;
  67
  68 static ent_t ext_ent = {0, 0, NULL, 0, NULL, NULL, {NULL, 0, 0}};
  69
  70 /* Protect global state against multiple changers.  */
  71 __libc_lock_define_initialized (static, lock)
  72
  73 /* Prototypes for local functions.  */
  74 static void blacklist_store_name (const char *, ent_t *);
  75 static int in_blacklist (const char *, int, ent_t *);
  76
  77 static enum nss_status
  78 _nss_first_init (void)
  79 {
  80   if (ni == NULL)
  81     {
  82       __nss_database_lookup ("group_compat", NULL, "nis", &ni);
  83       use_nisplus = (strcmp (ni->name, "nisplus") == 0);
  84     }
  85
  86   if (grptable == NULL)
  87     {
  88       static const char key[] = "group.org_dir.";
  89       const char *local_dir = nis_local_directory ();
  90       size_t len_local_dir = strlen (local_dir);
  91
  92       grptable = malloc (sizeof (key) + len_local_dir);
  93       if (grptable == NULL)
  94         return NSS_STATUS_TRYAGAIN;
  95
  96       grptablelen = ((char *) mempcpy (mempcpy (grptable,
  97                                                 key, sizeof (key) - 1),
  98                                        local_dir, len_local_dir + 1)
  99                      - grptable) - 1;
 100     }
 101
 102   return NSS_STATUS_SUCCESS;
 103 }
 104
 105 static enum nss_status
 106 internal_setgrent (ent_t *ent)
 107 {
 108   enum nss_status status = NSS_STATUS_SUCCESS;
 109
 110   ent->nis = ent->nis_first = 0;
 111
 112   if (_nss_first_init () != NSS_STATUS_SUCCESS)
 113     return NSS_STATUS_UNAVAIL;
 114
 115   if (ent->oldkey != NULL)
 116     {
 117       free (ent->oldkey);
 118       ent->oldkey = NULL;
 119       ent->oldkeylen = 0;
 120     }
 121
 122   if (ent->result != NULL)
 123     {
 124       nis_freeresult (ent->result);
 125       ent->result = NULL;
 126     }
 127
 128   if (ent->blacklist.data != NULL)
 129     {
 130       ent->blacklist.current = 1;
 131       ent->blacklist.data[0] = '|';
 132       ent->blacklist.data[1] = '\0';
 133     }
 134   else
 135     ent->blacklist.current = 0;
 136
 137   if (ent->stream == NULL)
 138     {
 139       ent->stream = fopen ("/etc/group", "r");
 140
 141       if (ent->stream == NULL)
 142         status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
 143       else
 144         {
 145           /* We have to make sure the file is  `closed on exec'.  */
 146           int result, flags;
 147
 148           result = flags = fcntl (fileno (ent->stream), F_GETFD, 0);
 149           if (result >= 0)
 150             {
 151               flags |= FD_CLOEXEC;
 152               result = fcntl (fileno (ent->stream), F_SETFD, flags);
 153             }
 154           if (result < 0)
 155             {
 156               /* Something went wrong.  Close the stream and return a
 157                  failure.  */
 158               fclose (ent->stream);
 159               ent->stream = NULL;
 160               status = NSS_STATUS_UNAVAIL;
 161             }
 162         }
 163     }
 164   else
 165     rewind (ent->stream);
 166
 167   return status;
 168 }
 169
 170
 171 enum nss_status
 172 _nss_compat_setgrent (void)
 173 {
 174   enum nss_status result;
 175
 176   __libc_lock_lock (lock);
 177
 178   result = internal_setgrent (&ext_ent);
 179
 180   __libc_lock_unlock (lock);
 181
 182   return result;
 183 }
 184
 185
 186 static enum nss_status
 187 internal_endgrent (ent_t *ent)
 188 {
 189   if (ent->stream != NULL)
 190     {
 191       fclose (ent->stream);
 192       ent->stream = NULL;
 193     }
 194
 195   ent->nis = ent->nis_first = 0;
 196
 197   if (ent->oldkey != NULL)
 198     {
 199       free (ent->oldkey);
 200       ent->oldkey = NULL;
 201       ent->oldkeylen = 0;
 202     }
 203
 204   if (ent->result != NULL)
 205     {
 206       nis_freeresult (ent->result);
 207       ent->result = NULL;
 208     }
 209
 210   if (ent->blacklist.data != NULL)
 211     {
 212       ent->blacklist.current = 1;
 213       ent->blacklist.data[0] = '|';
 214       ent->blacklist.data[1] = '\0';
 215     }
 216   else
 217     ent->blacklist.current = 0;
 218
 219   return NSS_STATUS_SUCCESS;
 220 }
 221
 222 enum nss_status
 223 _nss_compat_endgrent (void)
 224 {
 225   enum nss_status result;
 226
 227   __libc_lock_lock (lock);
 228
 229   result = internal_endgrent (&ext_ent);
 230
 231   __libc_lock_unlock (lock);
 232
 233   return result;
 234 }
 235
 236 static enum nss_status
 237 getgrent_next_nis (struct group *result, ent_t *ent, char *buffer,
 238                    size_t buflen, int *errnop)
 239 {
 240   struct parser_data *data = (void *) buffer;
 241   char *domain;
 242   char *outkey, *outval;
 243   int outkeylen, outvallen, parse_res;
 244   char *p;
 245
 246   if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
 247     {
 248       ent->nis = 0;
 249       return NSS_STATUS_NOTFOUND;
 250     }
 251
 252   do
 253     {
 254       char *save_oldkey;
 255       int save_oldlen;
 256       bool_t save_nis_first;
 257
 258       if (ent->nis_first)
 259         {
 260           if (yp_first (domain, "group.byname", &outkey, &outkeylen,
 261                         &outval, &outvallen) != YPERR_SUCCESS)
 262             {
 263               ent->nis = 0;
 264               return NSS_STATUS_UNAVAIL;
 265             }
 266           save_oldkey = ent->oldkey;
 267           save_oldlen = ent->oldkeylen;
 268           save_nis_first = TRUE;
 269           ent->oldkey = outkey;
 270           ent->oldkeylen = outkeylen;
 271           ent->nis_first = FALSE;
 272         }
 273       else
 274         {
 275           if (yp_next (domain, "group.byname", ent->oldkey, ent->oldkeylen,
 276                        &outkey, &outkeylen, &outval, &outvallen)
 277               != YPERR_SUCCESS)
 278             {
 279               ent->nis = 0;
 280               return NSS_STATUS_NOTFOUND;
 281             }
 282
 283           save_oldkey = ent->oldkey;
 284           save_oldlen = ent->oldkeylen;
 285           save_nis_first = FALSE;
 286           ent->oldkey = outkey;
 287           ent->oldkeylen = outkeylen;
 288         }
 289
 290       /* Copy the found data to our buffer  */
 291       p = strncpy (buffer, outval, buflen);
 292
 293       /* ...and free the data.  */
 294       free (outval);
 295
 296       while (isspace (*p))
 297         ++p;
 298
 299       parse_res = _nss_files_parse_grent (p, result, data, buflen, errnop);
 300       if (parse_res == -1)
 301         {
 302           free (ent->oldkey);
 303           ent->oldkey = save_oldkey;
 304           ent->oldkeylen = save_oldlen;
 305           ent->nis_first = save_nis_first;
 306           *errnop = ERANGE;
 307           return NSS_STATUS_TRYAGAIN;
 308         }
 309       else
 310         {
 311           if (!save_nis_first)
 312             free (save_oldkey);
 313         }
 314
 315       if (parse_res &&
 316           in_blacklist (result->gr_name, strlen (result->gr_name), ent))
 317         parse_res = 0; /* if result->gr_name in blacklist,search next entry */
 318     }
 319   while (!parse_res);
 320
 321   return NSS_STATUS_SUCCESS;
 322 }
 323
 324 static enum nss_status
 325 getgrent_next_nisplus (struct group *result, ent_t *ent, char *buffer,
 326                        size_t buflen, int *errnop)
 327 {
 328   int parse_res;
 329
 330   do
 331     {
 332       nis_result *save_oldres;
 333       bool_t save_nis_first;
 334
 335       if (ent->nis_first)
 336         {
 337           save_oldres = ent->result;
 338           save_nis_first = TRUE;
 339           ent->result = nis_first_entry(grptable);
 340           if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
 341             {
 342               ent->nis = 0;
 343               return niserr2nss (ent->result->status);
 344             }
 345           ent->nis_first = FALSE;
 346         }
 347       else
 348         {
 349           nis_result *res;
 350
 351           save_oldres = ent->result;
 352           save_nis_first = FALSE;
 353           res = nis_next_entry(grptable, &ent->result->cookie);
 354           ent->result = res;
 355           if (niserr2nss (ent->result->status) != NSS_STATUS_SUCCESS)
 356             {
 357               ent->nis = 0;
 358               return niserr2nss (ent->result->status);
 359             }
 360         }
 361       parse_res = _nss_nisplus_parse_grent (ent->result, 0, result,
 362                                             buffer, buflen, errnop);
 363       if (parse_res == -1)
 364         {
 365           nis_freeresult (ent->result);
 366           ent->result = save_oldres;
 367           ent->nis_first = save_nis_first;
 368           *errnop = ERANGE;
 369           return NSS_STATUS_TRYAGAIN;
 370         }
 371       else
 372         {
 373           if (!save_nis_first)
 374             nis_freeresult (save_oldres);
 375         }
 376
 377       if (parse_res &&
 378           in_blacklist (result->gr_name, strlen (result->gr_name), ent))
 379         parse_res = 0; /* if result->gr_name in blacklist,search next entry */
 380     }
 381   while (!parse_res);
 382
 383   return NSS_STATUS_SUCCESS;
 384 }
 385
 386 /* This function handle the +group entrys in /etc/group */
 387 static enum nss_status
 388 getgrnam_plusgroup (const char *name, struct group *result, char *buffer,
 389                     size_t buflen, int *errnop)
 390 {
 391   struct parser_data *data = (void *) buffer;
 392   int parse_res;
 393
 394   if (use_nisplus) /* Do the NIS+ query here */
 395     {
 396       nis_result *res;
 397       char buf[strlen (name) + 24 + grptablelen];
 398
 399       sprintf(buf, "[name=%s],%s", name, grptable);
 400       res = nis_list(buf, FOLLOW_PATH | FOLLOW_LINKS, NULL, NULL);
 401       if (niserr2nss (res->status) != NSS_STATUS_SUCCESS)
 402         {
 403           enum nss_status status =  niserr2nss (res->status);
 404
 405           nis_freeresult (res);
 406           return status;
 407         }
 408       parse_res = _nss_nisplus_parse_grent (res, 0, result, buffer, buflen,
 409                                             errnop);
 410       if (parse_res == -1)
 411         {
 412           nis_freeresult (res);
 413           *errnop = ERANGE;
 414           return NSS_STATUS_TRYAGAIN;
 415         }
 416       nis_freeresult (res);
 417     }
 418   else /* Use NIS */
 419     {
 420       char *domain, *outval, *p;
 421       int outvallen;
 422
 423       if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
 424         return NSS_STATUS_NOTFOUND;
 425
 426       if (yp_match (domain, "group.byname", name, strlen (name),
 427                     &outval, &outvallen) != YPERR_SUCCESS)
 428         return NSS_STATUS_NOTFOUND;
 429
 430       p = strncpy (buffer, outval,
 431                    buflen < (size_t) outvallen ? buflen : (size_t) outvallen);
 432       free (outval);
 433       while (isspace (*p))
 434         ++p;
 435       parse_res = _nss_files_parse_grent (p, result, data, buflen, errnop);
 436       if (parse_res == -1)
 437         return NSS_STATUS_TRYAGAIN;
 438     }
 439
 440   if (parse_res)
 441     /* We found the entry.  */
 442     return NSS_STATUS_SUCCESS;
 443   else
 444     return NSS_STATUS_RETURN;
 445 }
 446
 447 static enum nss_status
 448 getgrent_next_file (struct group *result, ent_t *ent,
 449                     char *buffer, size_t buflen, int *errnop)
 450 {
 451   struct parser_data *data = (void *) buffer;
 452   while (1)
 453     {
 454       fpos_t pos;
 455       int parse_res = 0;
 456       char *p;
 457
 458       do
 459         {
 460           fgetpos (ent->stream, &pos);
 461           p = fgets (buffer, buflen, ent->stream);
 462           if (p == NULL)
 463             {
 464               if (feof (ent->stream))
 465                 return NSS_STATUS_NOTFOUND;
 466               else
 467                 {
 468                   fsetpos (ent->stream, &pos);
 469                   *errnop = ERANGE;
 470                   return NSS_STATUS_TRYAGAIN;
 471                 }
 472             }
 473
 474           /* Terminate the line for any case.  */
 475           buffer[buflen - 1] = '\0';
 476
 477           /* Skip leading blanks.  */
 478           while (isspace (*p))
 479             ++p;
 480         }
 481       while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
 482       /* Parse the line.  If it is invalid, loop to
 483          get the next line of the file to parse.  */
 484              !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
 485                                                    errnop)));
 486
 487       if (parse_res == -1)
 488         {
 489           /* The parser ran out of space.  */
 490           fsetpos (ent->stream, &pos);
 491           *errnop = ERANGE;
 492           return NSS_STATUS_TRYAGAIN;
 493         }
 494
 495       if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
 496         /* This is a real entry.  */
 497         break;
 498
 499       /* -group */
 500       if (result->gr_name[0] == '-' && result->gr_name[1] != '\0'
 501           && result->gr_name[1] != '@')
 502         {
 503           blacklist_store_name (&result->gr_name[1], ent);
 504           continue;
 505         }
 506
 507       /* +group */
 508       if (result->gr_name[0] == '+' && result->gr_name[1] != '\0'
 509           && result->gr_name[1] != '@')
 510         {
 511           enum nss_status status;
 512
 513           /* Store the group in the blacklist for the "+" at the end of
 514              /etc/group */
 515           blacklist_store_name (&result->gr_name[1], ent);
 516           status = getgrnam_plusgroup (&result->gr_name[1], result, buffer,
 517                                        buflen, errnop);
 518           if (status == NSS_STATUS_SUCCESS) /* We found the entry. */
 519             break;
 520           else
 521             if (status == NSS_STATUS_RETURN /* We couldn't parse the entry */
 522                 || status == NSS_STATUS_NOTFOUND) /* No group in NIS */
 523               continue;
 524             else
 525               {
 526                 if (status == NSS_STATUS_TRYAGAIN)
 527                   {
 528                     /* The parser ran out of space.  */
 529                     fsetpos (ent->stream, &pos);
 530                     *errnop = ERANGE;
 531                   }
 532                 return status;
 533               }
 534         }
 535
 536       /* +:... */
 537       if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
 538         {
 539           ent->nis = TRUE;
 540           ent->nis_first = TRUE;
 541
 542           if (use_nisplus)
 543             return getgrent_next_nisplus (result, ent, buffer, buflen, errnop);
 544           else
 545             return getgrent_next_nis (result, ent, buffer, buflen, errnop);
 546         }
 547     }
 548
 549   return NSS_STATUS_SUCCESS;
 550 }
 551
 552
 553 static enum nss_status
 554 internal_getgrent_r (struct group *gr, ent_t *ent, char *buffer,
 555                      size_t buflen, int *errnop)
 556 {
 557   if (ent->nis)
 558     {
 559       if (use_nisplus)
 560         return getgrent_next_nisplus (gr, ent, buffer, buflen, errnop);
 561       else
 562         return getgrent_next_nis (gr, ent, buffer, buflen, errnop);
 563     }
 564   else
 565     return getgrent_next_file (gr, ent, buffer, buflen, errnop);
 566 }
 567
 568 enum nss_status
 569 _nss_compat_getgrent_r (struct group *grp, char *buffer, size_t buflen,
 570                         int *errnop)
 571 {
 572   enum nss_status status = NSS_STATUS_SUCCESS;
 573
 574   __libc_lock_lock (lock);
 575
 576   /* Be prepared that the setgrent function was not called before.  */
 577   if (ext_ent.stream == NULL)
 578     status = internal_setgrent (&ext_ent);
 579
 580   if (status == NSS_STATUS_SUCCESS)
 581     status = internal_getgrent_r (grp, &ext_ent, buffer, buflen, errnop);
 582
 583   __libc_lock_unlock (lock);
 584
 585   return status;
 586 }
 587
 588 /* Searches in /etc/group and the NIS/NIS+ map for a special group */
 589 static enum nss_status
 590 internal_getgrnam_r (const char *name, struct group *result, ent_t *ent,
 591                      char *buffer, size_t buflen, int *errnop)
 592 {
 593   struct parser_data *data = (void *) buffer;
 594   while (1)
 595     {
 596       fpos_t pos;
 597       int parse_res = 0;
 598       char *p;
 599
 600       do
 601         {
 602           fgetpos (ent->stream, &pos);
 603           p = fgets (buffer, buflen, ent->stream);
 604           if (p == NULL)
 605             {
 606               if (feof (ent->stream))
 607                 return NSS_STATUS_NOTFOUND;
 608               else
 609                 {
 610                   fsetpos (ent->stream, &pos);
 611                   *errnop = ERANGE;
 612                   return NSS_STATUS_TRYAGAIN;
 613                 }
 614             }
 615
 616           /* Terminate the line for any case.  */
 617           buffer[buflen - 1] = '\0';
 618
 619           /* Skip leading blanks.  */
 620           while (isspace (*p))
 621             ++p;
 622         }
 623       while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
 624       /* Parse the line.  If it is invalid, loop to
 625          get the next line of the file to parse.  */
 626              !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
 627                                                    errnop)));
 628
 629       if (parse_res == -1)
 630         {
 631           /* The parser ran out of space.  */
 632           fsetpos (ent->stream, &pos);
 633           *errnop = ERANGE;
 634           return NSS_STATUS_TRYAGAIN;
 635         }
 636
 637       /* This is a real entry.  */
 638       if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
 639         {
 640           if (strcmp (result->gr_name, name) == 0)
 641             return NSS_STATUS_SUCCESS;
 642           else
 643             continue;
 644         }
 645
 646       /* -group */
 647       if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
 648         {
 649           if (strcmp (&result->gr_name[1], name) == 0)
 650             return NSS_STATUS_NOTFOUND;
 651           else
 652             continue;
 653         }
 654
 655       /* +group */
 656       if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
 657         {
 658           if (strcmp (name, &result->gr_name[1]) == 0)
 659             {
 660               enum nss_status status;
 661
 662               status = getgrnam_plusgroup (name, result, buffer, buflen,
 663                                            errnop);
 664               if (status == NSS_STATUS_RETURN)
 665                 /* We couldn't parse the entry */
 666                 continue;
 667               else
 668                 return status;
 669             }
 670         }
 671       /* +:... */
 672       if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
 673         {
 674           enum nss_status status;
 675
 676           status = getgrnam_plusgroup (name, result, buffer, buflen, errnop);
 677           if (status == NSS_STATUS_RETURN)
 678             /* We couldn't parse the entry */
 679             continue;
 680           else
 681             return status;
 682         }
 683     }
 684
 685   return NSS_STATUS_SUCCESS;
 686 }
 687
 688 enum nss_status
 689 _nss_compat_getgrnam_r (const char *name, struct group *grp,
 690                         char *buffer, size_t buflen, int *errnop)
 691 {
 692   ent_t ent = {0, 0, NULL, 0, NULL, NULL, {NULL, 0, 0}};
 693   enum nss_status status;
 694
 695   if (name[0] == '-' || name[0] == '+')
 696     return NSS_STATUS_NOTFOUND;
 697
 698   __libc_lock_lock (lock);
 699
 700   status = internal_setgrent (&ent);
 701
 702   __libc_lock_unlock (lock);
 703
 704   if (status != NSS_STATUS_SUCCESS)
 705     return status;
 706
 707   status = internal_getgrnam_r (name, grp, &ent, buffer, buflen, errnop);
 708
 709   internal_endgrent (&ent);
 710
 711   return status;
 712 }
 713
 714 /* This function handle the + entry in /etc/group */
 715 static enum nss_status
 716 getgrgid_plusgroup (gid_t gid, struct group *result, char *buffer,
 717                     size_t buflen, int *errnop)
 718 {
 719   struct parser_data *data = (void *) buffer;
 720   int parse_res;
 721
 722   if (use_nisplus) /* Do the NIS+ query here */
 723     {
 724       nis_result *res;
 725       char buf[24 + grptablelen];
 726
 727       sprintf(buf, "[gid=%d],%s", gid, grptable);
 728       res = nis_list(buf, FOLLOW_PATH | FOLLOW_LINKS, NULL, NULL);
 729       if (niserr2nss (res->status) != NSS_STATUS_SUCCESS)
 730         {
 731           enum nss_status status =  niserr2nss (res->status);
 732
 733           nis_freeresult (res);
 734           return status;
 735         }
 736       if ((parse_res = _nss_nisplus_parse_grent (res, 0, result, buffer,
 737                                                  buflen, errnop)) == -1)
 738         {
 739           nis_freeresult (res);
 740           *errnop = ERANGE;
 741           return NSS_STATUS_TRYAGAIN;
 742         }
 743       nis_freeresult (res);
 744     }
 745   else /* Use NIS */
 746     {
 747       char buf[24];
 748       char *domain, *outval, *p;
 749       int outvallen;
 750
 751       if (yp_get_default_domain (&domain) != YPERR_SUCCESS)
 752         {
 753           *errnop = errno;
 754           return NSS_STATUS_TRYAGAIN;
 755         }
 756
 757       snprintf (buf, sizeof (buf), "%d", gid);
 758
 759       if (yp_match (domain, "group.bygid", buf, strlen (buf),
 760                     &outval, &outvallen) != YPERR_SUCCESS)
 761         {
 762           *errnop = errno;
 763           return NSS_STATUS_TRYAGAIN;
 764         }
 765       p = strncpy (buffer, outval,
 766                    buflen < (size_t) outvallen ? buflen : (size_t) outvallen);
 767       free (outval);
 768       while (isspace (*p))
 769         p++;
 770       parse_res = _nss_files_parse_grent (p, result, data, buflen, errnop);
 771       if (parse_res == -1)
 772         return NSS_STATUS_TRYAGAIN;
 773     }
 774
 775   if (parse_res)
 776     /* We found the entry.  */
 777     return NSS_STATUS_SUCCESS;
 778   else
 779     return NSS_STATUS_RETURN;
 780 }
 781
 782 /* Searches in /etc/group and the NIS/NIS+ map for a special group id */
 783 static enum nss_status
 784 internal_getgrgid_r (gid_t gid, struct group *result, ent_t *ent,
 785                      char *buffer, size_t buflen, int *errnop)
 786 {
 787   struct parser_data *data = (void *) buffer;
 788   while (1)
 789     {
 790       fpos_t pos;
 791       int parse_res = 0;
 792       char *p;
 793
 794       do
 795         {
 796           fgetpos (ent->stream, &pos);
 797           p = fgets (buffer, buflen, ent->stream);
 798           if (p == NULL)
 799             {
 800               if (feof (ent->stream))
 801                 return NSS_STATUS_NOTFOUND;
 802               else
 803                 {
 804                   fsetpos (ent->stream, &pos);
 805                   *errnop = ERANGE;
 806                   return NSS_STATUS_TRYAGAIN;
 807                 }
 808             }
 809
 810           /* Terminate the line for any case.  */
 811           buffer[buflen - 1] = '\0';
 812
 813           /* Skip leading blanks.  */
 814           while (isspace (*p))
 815             ++p;
 816         }
 817       while (*p == '\0' || *p == '#' || /* Ignore empty and comment lines. */
 818       /* Parse the line.  If it is invalid, loop to
 819          get the next line of the file to parse.  */
 820              !(parse_res = _nss_files_parse_grent (p, result, data, buflen,
 821                                                    errnop)));
 822
 823       if (parse_res == -1)
 824         {
 825           /* The parser ran out of space.  */
 826           fsetpos (ent->stream, &pos);
 827           *errnop = ERANGE;
 828           return NSS_STATUS_TRYAGAIN;
 829         }
 830
 831       /* This is a real entry.  */
 832       if (result->gr_name[0] != '+' && result->gr_name[0] != '-')
 833         {
 834           if (result->gr_gid == gid)
 835             return NSS_STATUS_SUCCESS;
 836           else
 837             continue;
 838         }
 839
 840       /* -group */
 841       if (result->gr_name[0] == '-' && result->gr_name[1] != '\0')
 842         {
 843           blacklist_store_name (&result->gr_name[1], ent);
 844           continue;
 845         }
 846
 847       /* +group */
 848       if (result->gr_name[0] == '+' && result->gr_name[1] != '\0')
 849         {
 850           enum nss_status status;
 851
 852           /* Store the group in the blacklist for the "+" at the end of
 853              /etc/group */
 854           blacklist_store_name (&result->gr_name[1], ent);
 855           status = getgrnam_plusgroup (&result->gr_name[1], result, buffer,
 856                                       buflen, errnop);
 857           if (status == NSS_STATUS_SUCCESS && result->gr_gid == gid)
 858             break;
 859           else
 860             continue;
 861         }
 862       /* +:... */
 863       if (result->gr_name[0] == '+' && result->gr_name[1] == '\0')
 864         {
 865           enum nss_status status;
 866
 867           status = getgrgid_plusgroup (gid, result, buffer, buflen, errnop);
 868           if (status == NSS_STATUS_RETURN) /* We couldn't parse the entry */
 869             return NSS_STATUS_NOTFOUND;
 870           else
 871             return status;
 872         }
 873     }
 874
 875   return NSS_STATUS_SUCCESS;
 876 }
 877
 878 enum nss_status
 879 _nss_compat_getgrgid_r (gid_t gid, struct group *grp,
 880                         char *buffer, size_t buflen, int *errnop)
 881 {
 882   ent_t ent = {0, 0, NULL, 0, NULL, NULL, {NULL, 0, 0}};
 883   enum nss_status status;
 884
 885   __libc_lock_lock (lock);
 886
 887   status = internal_setgrent (&ent);
 888
 889   __libc_lock_unlock (lock);
 890
 891   if (status != NSS_STATUS_SUCCESS)
 892     return status;
 893
 894   status = internal_getgrgid_r (gid, grp, &ent, buffer, buflen, errnop);
 895
 896   internal_endgrent (&ent);
 897
 898   return status;
 899 }
 900
 901
 902 /* Support routines for remembering -@netgroup and -user entries.
 903    The names are stored in a single string with `|' as separator. */
 904 static void
 905 blacklist_store_name (const char *name, ent_t *ent)
 906 {
 907   int namelen = strlen (name);
 908   char *tmp;
 909
 910   /* first call, setup cache */
 911   if (ent->blacklist.size == 0)
 912     {
 913       ent->blacklist.size = MAX (BLACKLIST_INITIAL_SIZE, 2 * namelen);
 914       ent->blacklist.data = malloc (ent->blacklist.size);
 915       if (ent->blacklist.data == NULL)
 916         return;
 917       ent->blacklist.data[0] = '|';
 918       ent->blacklist.data[1] = '\0';
 919       ent->blacklist.current = 1;
 920     }
 921   else
 922     {
 923       if (in_blacklist (name, namelen, ent))
 924         return;                 /* no duplicates */
 925
 926       if (ent->blacklist.current + namelen + 1 >= ent->blacklist.size)
 927         {
 928           ent->blacklist.size += MAX (BLACKLIST_INCREMENT, 2 * namelen);
 929           tmp = realloc (ent->blacklist.data, ent->blacklist.size);
 930           if (tmp == NULL)
 931             {
 932               free (ent->blacklist.data);
 933               ent->blacklist.size = 0;
 934               return;
 935             }
 936           ent->blacklist.data = tmp;
 937         }
 938     }
 939
 940   tmp = stpcpy (ent->blacklist.data + ent->blacklist.current, name);
 941   *tmp++ = '|';
 942   *tmp = '\0';
 943   ent->blacklist.current += namelen + 1;
 944
 945   return;
 946 }
 947
 948 /* returns TRUE if ent->blacklist contains name, else FALSE */
 949 static bool_t
 950 in_blacklist (const char *name, int namelen, ent_t *ent)
 951 {
 952   char buf[namelen + 3];
 953   char *cp;
 954
 955   if (ent->blacklist.data == NULL)
 956     return FALSE;
 957
 958   buf[0] = '|';
 959   cp = stpcpy (&buf[1], name);
 960   *cp++= '|';
 961   *cp = '\0';
 962   return strstr (ent->blacklist.data, buf) != NULL;
 963 }