lib/libc/gen/pwcache.c

   1 /*      $NetBSD: pwcache.c,v 1.31 2010/03/23 20:28:59 drochner Exp $    */
   2
   3 /*-
   4  * Copyright (c) 1992 Keith Muller.
   5  * Copyright (c) 1992, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * Keith Muller of the University of California, San Diego.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. 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
  36 /*-
  37  * Copyright (c) 2002 The NetBSD Foundation, Inc.
  38  * All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  50  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  51  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  52  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  53  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  54  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  55  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  56  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  57  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  58  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  59  * POSSIBILITY OF SUCH DAMAGE.
  60  */
  61
  62 #if HAVE_NBTOOL_CONFIG_H
  63 #include "nbtool_config.h"
  64 /*
  65  * XXX Undefine the renames of these functions so that we don't
  66  * XXX rename the versions found in the host's <pwd.h> by mistake!
  67  */
  68 #undef group_from_gid
  69 #undef user_from_uid
  70 #endif
  71
  72 #include <sys/cdefs.h>
  73 #if defined(LIBC_SCCS) && !defined(lint)
  74 #if 0
  75 static char sccsid[] = "@(#)cache.c     8.1 (Berkeley) 5/31/93";
  76 #else
  77 __RCSID("$NetBSD: pwcache.c,v 1.31 2010/03/23 20:28:59 drochner Exp $");
  78 #endif
  79 #endif /* LIBC_SCCS and not lint */
  80
  81 #include "namespace.h"
  82
  83 #include <sys/types.h>
  84 #include <sys/param.h>
  85
  86 #include <assert.h>
  87 #include <grp.h>
  88 #include <pwd.h>
  89 #include <stdio.h>
  90 #include <stdlib.h>
  91 #include <string.h>
  92 #include <unistd.h>
  93
  94 #if HAVE_NBTOOL_CONFIG_H
  95 /* XXX Now, re-apply the renaming that we undid above. */
  96 #define group_from_gid  __nbcompat_group_from_gid
  97 #define user_from_uid   __nbcompat_user_from_uid
  98 #endif
  99
 100 #ifdef __weak_alias
 101 __weak_alias(user_from_uid,_user_from_uid)
 102 __weak_alias(group_from_gid,_group_from_gid)
 103 __weak_alias(pwcache_groupdb,_pwcache_groupdb)
 104 #endif
 105
 106 #if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_H
 107 #include "pwcache.h"
 108
 109 /*
 110  * routines that control user, group, uid and gid caches (for the archive
 111  * member print routine).
 112  * IMPORTANT:
 113  * these routines cache BOTH hits and misses, a major performance improvement
 114  */
 115
 116 /*
 117  * function pointers to various name lookup routines.
 118  * these may be changed as necessary.
 119  */
 120 static  int             (*_pwcache_setgroupent)(int)            = setgroupent;
 121 static  void            (*_pwcache_endgrent)(void)              = endgrent;
 122 static  struct group *  (*_pwcache_getgrnam)(const char *)      = getgrnam;
 123 static  struct group *  (*_pwcache_getgrgid)(gid_t)             = getgrgid;
 124 static  int             (*_pwcache_setpassent)(int)             = setpassent;
 125 static  void            (*_pwcache_endpwent)(void)              = endpwent;
 126 static  struct passwd * (*_pwcache_getpwnam)(const char *)      = getpwnam;
 127 static  struct passwd * (*_pwcache_getpwuid)(uid_t)             = getpwuid;
 128
 129 /*
 130  * internal state
 131  */
 132 static  int     pwopn;          /* is password file open */
 133 static  int     gropn;          /* is group file open */
 134 static  UIDC    **uidtb;        /* uid to name cache */
 135 static  GIDC    **gidtb;        /* gid to name cache */
 136 static  UIDC    **usrtb;        /* user name to uid cache */
 137 static  GIDC    **grptb;        /* group name to gid cache */
 138
 139 static  int     uidtb_fail;     /* uidtb_start() failed ? */
 140 static  int     gidtb_fail;     /* gidtb_start() failed ? */
 141 static  int     usrtb_fail;     /* usrtb_start() failed ? */
 142 static  int     grptb_fail;     /* grptb_start() failed ? */
 143
 144
 145 static  u_int   st_hash(const char *, size_t, int);
 146 static  int     uidtb_start(void);
 147 static  int     gidtb_start(void);
 148 static  int     usrtb_start(void);
 149 static  int     grptb_start(void);
 150
 151
 152 static u_int
 153 st_hash(const char *name, size_t len, int tabsz)
 154 {
 155         u_int key = 0;
 156
 157         _DIAGASSERT(name != NULL);
 158
 159         while (len--) {
 160                 key += *name++;
 161                 key = (key << 8) | (key >> 24);
 162         }
 163
 164         return (key % tabsz);
 165 }
 166
 167 /*
 168  * uidtb_start
 169  *      creates an an empty uidtb
 170  * Return:
 171  *      0 if ok, -1 otherwise
 172  */
 173 static int
 174 uidtb_start(void)
 175 {
 176
 177         if (uidtb != NULL)
 178                 return (0);
 179         if (uidtb_fail)
 180                 return (-1);
 181         if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
 182                 ++uidtb_fail;
 183                 return (-1);
 184         }
 185         return (0);
 186 }
 187
 188 /*
 189  * gidtb_start
 190  *      creates an an empty gidtb
 191  * Return:
 192  *      0 if ok, -1 otherwise
 193  */
 194 static int
 195 gidtb_start(void)
 196 {
 197
 198         if (gidtb != NULL)
 199                 return (0);
 200         if (gidtb_fail)
 201                 return (-1);
 202         if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
 203                 ++gidtb_fail;
 204                 return (-1);
 205         }
 206         return (0);
 207 }
 208
 209 /*
 210  * usrtb_start
 211  *      creates an an empty usrtb
 212  * Return:
 213  *      0 if ok, -1 otherwise
 214  */
 215 static int
 216 usrtb_start(void)
 217 {
 218
 219         if (usrtb != NULL)
 220                 return (0);
 221         if (usrtb_fail)
 222                 return (-1);
 223         if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
 224                 ++usrtb_fail;
 225                 return (-1);
 226         }
 227         return (0);
 228 }
 229
 230 /*
 231  * grptb_start
 232  *      creates an an empty grptb
 233  * Return:
 234  *      0 if ok, -1 otherwise
 235  */
 236 static int
 237 grptb_start(void)
 238 {
 239
 240         if (grptb != NULL)
 241                 return (0);
 242         if (grptb_fail)
 243                 return (-1);
 244         if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
 245                 ++grptb_fail;
 246                 return (-1);
 247         }
 248         return (0);
 249 }
 250
 251 /*
 252  * user_from_uid()
 253  *      caches the name (if any) for the uid. If noname clear, we always
 254  *      return the stored name (if valid or invalid match).
 255  *      We use a simple hash table.
 256  * Return
 257  *      Pointer to stored name (or a empty string)
 258  */
 259 const char *
 260 user_from_uid(uid_t uid, int noname)
 261 {
 262         struct passwd *pw;
 263         UIDC *ptr, **pptr;
 264
 265         if ((uidtb == NULL) && (uidtb_start() < 0))
 266                 return (NULL);
 267
 268         /*
 269          * see if we have this uid cached
 270          */
 271         pptr = uidtb + (uid % UID_SZ);
 272         ptr = *pptr;
 273
 274         if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
 275                 /*
 276                  * have an entry for this uid
 277                  */
 278                 if (!noname || (ptr->valid == VALID))
 279                         return (ptr->name);
 280                 return (NULL);
 281         }
 282
 283         /*
 284          * No entry for this uid, we will add it
 285          */
 286         if (!pwopn) {
 287                 if (_pwcache_setpassent != NULL)
 288                         (*_pwcache_setpassent)(1);
 289                 ++pwopn;
 290         }
 291
 292         if (ptr == NULL)
 293                 *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
 294
 295         if ((pw = (*_pwcache_getpwuid)(uid)) == NULL) {
 296                 /*
 297                  * no match for this uid in the local password file
 298                  * a string that is the uid in numeric format
 299                  */
 300                 if (ptr == NULL)
 301                         return (NULL);
 302                 ptr->uid = uid;
 303                 (void)snprintf(ptr->name, UNMLEN, "%lu", (long) uid);
 304                 ptr->valid = INVALID;
 305                 if (noname)
 306                         return (NULL);
 307         } else {
 308                 /*
 309                  * there is an entry for this uid in the password file
 310                  */
 311                 if (ptr == NULL)
 312                         return (pw->pw_name);
 313                 ptr->uid = uid;
 314                 (void)strlcpy(ptr->name, pw->pw_name, UNMLEN);
 315                 ptr->valid = VALID;
 316         }
 317         return (ptr->name);
 318 }
 319
 320 /*
 321  * group_from_gid()
 322  *      caches the name (if any) for the gid. If noname clear, we always
 323  *      return the stored name (if valid or invalid match).
 324  *      We use a simple hash table.
 325  * Return
 326  *      Pointer to stored name (or a empty string)
 327  */
 328 const char *
 329 group_from_gid(gid_t gid, int noname)
 330 {
 331         struct group *gr;
 332         GIDC *ptr, **pptr;
 333
 334         if ((gidtb == NULL) && (gidtb_start() < 0))
 335                 return (NULL);
 336
 337         /*
 338          * see if we have this gid cached
 339          */
 340         pptr = gidtb + (gid % GID_SZ);
 341         ptr = *pptr;
 342
 343         if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
 344                 /*
 345                  * have an entry for this gid
 346                  */
 347                 if (!noname || (ptr->valid == VALID))
 348                         return (ptr->name);
 349                 return (NULL);
 350         }
 351
 352         /*
 353          * No entry for this gid, we will add it
 354          */
 355         if (!gropn) {
 356                 if (_pwcache_setgroupent != NULL)
 357                         (*_pwcache_setgroupent)(1);
 358                 ++gropn;
 359         }
 360
 361         if (ptr == NULL)
 362                 *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
 363
 364         if ((gr = (*_pwcache_getgrgid)(gid)) == NULL) {
 365                 /*
 366                  * no match for this gid in the local group file, put in
 367                  * a string that is the gid in numberic format
 368                  */
 369                 if (ptr == NULL)
 370                         return (NULL);
 371                 ptr->gid = gid;
 372                 (void)snprintf(ptr->name, GNMLEN, "%lu", (long) gid);
 373                 ptr->valid = INVALID;
 374                 if (noname)
 375                         return (NULL);
 376         } else {
 377                 /*
 378                  * there is an entry for this group in the group file
 379                  */
 380                 if (ptr == NULL)
 381                         return (gr->gr_name);
 382                 ptr->gid = gid;
 383                 (void)strlcpy(ptr->name, gr->gr_name, GNMLEN);
 384                 ptr->valid = VALID;
 385         }
 386         return (ptr->name);
 387 }
 388
 389 /*
 390  * uid_from_user()
 391  *      caches the uid for a given user name. We use a simple hash table.
 392  * Return
 393  *      the uid (if any) for a user name, or a -1 if no match can be found
 394  */
 395 int
 396 uid_from_user(const char *name, uid_t *uid)
 397 {
 398         struct passwd *pw;
 399         UIDC *ptr, **pptr;
 400         size_t namelen;
 401
 402         /*
 403          * return -1 for mangled names
 404          */
 405         if (name == NULL || ((namelen = strlen(name)) == 0))
 406                 return (-1);
 407         if ((usrtb == NULL) && (usrtb_start() < 0))
 408                 return (-1);
 409
 410         /*
 411          * look up in hash table, if found and valid return the uid,
 412          * if found and invalid, return a -1
 413          */
 414         pptr = usrtb + st_hash(name, namelen, UNM_SZ);
 415         ptr = *pptr;
 416
 417         if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
 418                 if (ptr->valid == INVALID)
 419                         return (-1);
 420                 *uid = ptr->uid;
 421                 return (0);
 422         }
 423
 424         if (!pwopn) {
 425                 if (_pwcache_setpassent != NULL)
 426                         (*_pwcache_setpassent)(1);
 427                 ++pwopn;
 428         }
 429
 430         if (ptr == NULL)
 431                 *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));
 432
 433         /*
 434          * no match, look it up, if no match store it as an invalid entry,
 435          * or store the matching uid
 436          */
 437         if (ptr == NULL) {
 438                 if ((pw = (*_pwcache_getpwnam)(name)) == NULL)
 439                         return (-1);
 440                 *uid = pw->pw_uid;
 441                 return (0);
 442         }
 443         (void)strlcpy(ptr->name, name, UNMLEN);
 444         if ((pw = (*_pwcache_getpwnam)(name)) == NULL) {
 445                 ptr->valid = INVALID;
 446                 return (-1);
 447         }
 448         ptr->valid = VALID;
 449         *uid = ptr->uid = pw->pw_uid;
 450         return (0);
 451 }
 452
 453 /*
 454  * gid_from_group()
 455  *      caches the gid for a given group name. We use a simple hash table.
 456  * Return
 457  *      the gid (if any) for a group name, or a -1 if no match can be found
 458  */
 459 int
 460 gid_from_group(const char *name, gid_t *gid)
 461 {
 462         struct group *gr;
 463         GIDC *ptr, **pptr;
 464         size_t namelen;
 465
 466         /*
 467          * return -1 for mangled names
 468          */
 469         if (name == NULL || ((namelen = strlen(name)) == 0))
 470                 return (-1);
 471         if ((grptb == NULL) && (grptb_start() < 0))
 472                 return (-1);
 473
 474         /*
 475          * look up in hash table, if found and valid return the uid,
 476          * if found and invalid, return a -1
 477          */
 478         pptr = grptb + st_hash(name, namelen, GID_SZ);
 479         ptr = *pptr;
 480
 481         if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
 482                 if (ptr->valid == INVALID)
 483                         return (-1);
 484                 *gid = ptr->gid;
 485                 return (0);
 486         }
 487
 488         if (!gropn) {
 489                 if (_pwcache_setgroupent != NULL)
 490                         (*_pwcache_setgroupent)(1);
 491                 ++gropn;
 492         }
 493
 494         if (ptr == NULL)
 495                 *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));
 496
 497         /*
 498          * no match, look it up, if no match store it as an invalid entry,
 499          * or store the matching gid
 500          */
 501         if (ptr == NULL) {
 502                 if ((gr = (*_pwcache_getgrnam)(name)) == NULL)
 503                         return (-1);
 504                 *gid = gr->gr_gid;
 505                 return (0);
 506         }
 507
 508         (void)strlcpy(ptr->name, name, GNMLEN);
 509         if ((gr = (*_pwcache_getgrnam)(name)) == NULL) {
 510                 ptr->valid = INVALID;
 511                 return (-1);
 512         }
 513         ptr->valid = VALID;
 514         *gid = ptr->gid = gr->gr_gid;
 515         return (0);
 516 }
 517
 518 #define FLUSHTB(arr, len, fail)                         \
 519         do {                                            \
 520                 if (arr != NULL) {                      \
 521                         for (i = 0; i < len; i++)       \
 522                                 if (arr[i] != NULL)     \
 523                                         free(arr[i]);   \
 524                         arr = NULL;                     \
 525                 }                                       \
 526                 fail = 0;                               \
 527         } while (/* CONSTCOND */0);
 528
 529 int
 530 pwcache_userdb(
 531         int             (*a_setpassent)(int),
 532         void            (*a_endpwent)(void),
 533         struct passwd * (*a_getpwnam)(const char *),
 534         struct passwd * (*a_getpwuid)(uid_t))
 535 {
 536         int i;
 537
 538                 /* a_setpassent and a_endpwent may be NULL */
 539         if (a_getpwnam == NULL || a_getpwuid == NULL)
 540                 return (-1);
 541
 542         if (_pwcache_endpwent != NULL)
 543                 (*_pwcache_endpwent)();
 544         FLUSHTB(uidtb, UID_SZ, uidtb_fail);
 545         FLUSHTB(usrtb, UNM_SZ, usrtb_fail);
 546         pwopn = 0;
 547         _pwcache_setpassent = a_setpassent;
 548         _pwcache_endpwent = a_endpwent;
 549         _pwcache_getpwnam = a_getpwnam;
 550         _pwcache_getpwuid = a_getpwuid;
 551
 552         return (0);
 553 }
 554
 555 int
 556 pwcache_groupdb(
 557         int             (*a_setgroupent)(int),
 558         void            (*a_endgrent)(void),
 559         struct group *  (*a_getgrnam)(const char *),
 560         struct group *  (*a_getgrgid)(gid_t))
 561 {
 562         int i;
 563
 564                 /* a_setgroupent and a_endgrent may be NULL */
 565         if (a_getgrnam == NULL || a_getgrgid == NULL)
 566                 return (-1);
 567
 568         if (_pwcache_endgrent != NULL)
 569                 (*_pwcache_endgrent)();
 570         FLUSHTB(gidtb, GID_SZ, gidtb_fail);
 571         FLUSHTB(grptb, GNM_SZ, grptb_fail);
 572         gropn = 0;
 573         _pwcache_setgroupent = a_setgroupent;
 574         _pwcache_endgrent = a_endgrent;
 575         _pwcache_getgrnam = a_getgrnam;
 576         _pwcache_getgrgid = a_getgrgid;
 577
 578         return (0);
 579 }
 580
 581
 582 #ifdef TEST_PWCACHE
 583
 584 struct passwd *
 585 test_getpwnam(const char *name)
 586 {
 587         static struct passwd foo;
 588
 589         memset(&foo, 0, sizeof(foo));
 590         if (strcmp(name, "toor") == 0) {
 591                 foo.pw_uid = 666;
 592                 return &foo;
 593         }
 594         return (getpwnam(name));
 595 }
 596
 597 int
 598 main(int argc, char *argv[])
 599 {
 600         uid_t   u;
 601         int     r, i;
 602
 603         printf("pass 1 (default userdb)\n");
 604         for (i = 1; i < argc; i++) {
 605                 printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
 606                     i, pwopn, usrtb_fail, usrtb);
 607                 r = uid_from_user(argv[i], &u);
 608                 if (r == -1)
 609                         printf("  uid_from_user %s: failed\n", argv[i]);
 610                 else
 611                         printf("  uid_from_user %s: %d\n", argv[i], u);
 612         }
 613         printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n",
 614                     pwopn, usrtb_fail, usrtb);
 615
 616         puts("");
 617         printf("pass 2 (replacement userdb)\n");
 618         printf("pwcache_userdb returned %d\n",
 619             pwcache_userdb(setpassent, test_getpwnam, getpwuid));
 620         printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb);
 621
 622         for (i = 1; i < argc; i++) {
 623                 printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
 624                     i, pwopn, usrtb_fail, usrtb);
 625                 u = -1;
 626                 r = uid_from_user(argv[i], &u);
 627                 if (r == -1)
 628                         printf("  uid_from_user %s: failed\n", argv[i]);
 629                 else
 630                         printf("  uid_from_user %s: %d\n", argv[i], u);
 631         }
 632         printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n",
 633                     pwopn, usrtb_fail, usrtb);
 634
 635         puts("");
 636         printf("pass 3 (null pointers)\n");
 637         printf("pwcache_userdb returned %d\n",
 638             pwcache_userdb(NULL, NULL, NULL));
 639
 640         return (0);
 641 }
 642 #endif  /* TEST_PWCACHE */
 643 #endif  /* !HAVE_PWCACHE_USERDB */