nscd/pwdcache.c

   1 /* Copyright (c) 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1998.
   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 <malloc.h>
  22 #include <pthread.h>
  23 #include <pwd.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <rpcsvc/nis.h>
  27 #include <sys/types.h>
  28
  29 #include "dbg_log.h"
  30 #include "nscd.h"
  31
  32 static unsigned long int modulo = 211;
  33 static unsigned long int postimeout = 600;
  34 static unsigned long int negtimeout = 20;
  35
  36 static unsigned long int poshit = 0;
  37 static unsigned long int posmiss = 0;
  38 static unsigned long int neghit = 0;
  39 static unsigned long int negmiss = 0;
  40
  41 struct pwdhash
  42 {
  43   time_t create;
  44   struct pwdhash *next;
  45   struct passwd *pwd;
  46 };
  47 typedef struct pwdhash pwdhash;
  48
  49 struct uidhash
  50 {
  51   struct uidhash *next;
  52   struct passwd *pwptr;
  53 };
  54 typedef struct uidhash uidhash;
  55
  56 struct neghash
  57 {
  58   time_t create;
  59   struct neghash *next;
  60   char *key;
  61 };
  62 typedef struct neghash neghash;
  63
  64 static pwdhash *pwdtbl;
  65 static uidhash *uidtbl;
  66 static neghash *negtbl;
  67
  68 static pthread_rwlock_t pwdlock = PTHREAD_RWLOCK_INITIALIZER;
  69 static pthread_rwlock_t neglock = PTHREAD_RWLOCK_INITIALIZER;
  70
  71 static void *pwdtable_update (void *);
  72 static void *negtable_update (void *);
  73
  74 void
  75 get_pw_stat (stat_response_header *stat)
  76 {
  77   stat->pw_poshit = poshit;
  78   stat->pw_posmiss = posmiss;
  79   stat->pw_neghit = neghit;
  80   stat->pw_negmiss = negmiss;
  81   stat->pw_size = modulo;
  82   stat->pw_posttl = postimeout;
  83   stat->pw_negttl = negtimeout;
  84 }
  85
  86 void
  87 set_pwd_modulo (unsigned long int mod)
  88 {
  89   modulo = mod;
  90 }
  91
  92 void
  93 set_pos_pwd_ttl (unsigned long int ttl)
  94 {
  95   postimeout = ttl;
  96 }
  97
  98 void
  99 set_neg_pwd_ttl (unsigned long int ttl)
 100 {
 101   negtimeout = ttl;
 102 }
 103
 104 int
 105 cache_pwdinit ()
 106 {
 107   pthread_attr_t attr;
 108   pthread_t thread;
 109
 110   pwdtbl = calloc (modulo, sizeof (pwdhash));
 111   if (pwdtbl == NULL)
 112     return -1;
 113   uidtbl = calloc (modulo, sizeof (uidhash));
 114   if (uidtbl == NULL)
 115     return -1;
 116   negtbl = calloc (modulo, sizeof (neghash));
 117   if (negtbl == NULL)
 118     return -1;
 119
 120   pthread_attr_init (&attr);
 121   pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
 122
 123   pthread_create (&thread, NULL, pwdtable_update, &attr);
 124   pthread_create (&thread, NULL, negtable_update, &attr);
 125
 126   pthread_attr_destroy (&attr);
 127
 128   return 0;
 129 }
 130
 131 static struct passwd *
 132 save_pwd (struct passwd *src)
 133 {
 134   struct passwd *dest;
 135   size_t name_len = strlen (src->pw_name) + 1;
 136   size_t passwd_len = strlen (src->pw_gecos) + 1;
 137   size_t gecos_len = strlen (src->pw_dir) + 1;
 138   size_t dir_len = strlen (src->pw_dir) + 1;
 139   size_t shell_len = strlen (src->pw_shell) + 1;
 140   char *cp;
 141
 142   dest = malloc (sizeof (struct passwd)
 143                  + name_len + passwd_len + gecos_len + dir_len + shell_len);
 144   if (dest == NULL)
 145     return NULL;
 146
 147   cp = (char *) (dest + 1);
 148   dest->pw_name = cp;
 149   cp = mempcpy (cp, src->pw_name, name_len);
 150   dest->pw_passwd = cp;
 151   cp = mempcpy (cp, src->pw_passwd, passwd_len);
 152   dest->pw_uid = src->pw_uid;
 153   dest->pw_gid = src->pw_gid;
 154   dest->pw_gecos = cp;
 155   cp = mempcpy (cp, src->pw_gecos, gecos_len);
 156   dest->pw_dir = cp;
 157   cp = mempcpy (cp, src->pw_dir, dir_len);
 158   dest->pw_shell = cp;
 159   mempcpy (cp, src->pw_shell, shell_len);
 160
 161   return dest;
 162 }
 163
 164 static void
 165 free_pwd (struct passwd *src)
 166 {
 167   free (src);
 168 }
 169
 170 static int
 171 add_cache (struct passwd *pwd)
 172 {
 173   pwdhash *work;
 174   uidhash *uidwork;
 175   unsigned long int hash = __nis_hash (pwd->pw_name,
 176                                        strlen (pwd->pw_name)) % modulo;
 177
 178   if (debug_flag)
 179     dbg_log (_("pwd_add_cache (%s)"), pwd->pw_name);
 180
 181   work = &pwdtbl[hash];
 182
 183   if (pwdtbl[hash].pwd == NULL)
 184     pwdtbl[hash].pwd = save_pwd (pwd);
 185   else
 186     {
 187       while (work->next != NULL)
 188         work = work->next;
 189
 190       work->next = calloc (1, sizeof (pwdhash));
 191       work->next->pwd = save_pwd (pwd);
 192       work = work->next;
 193     }
 194   /* Set a pointer from the pwuid hash table to the pwname hash table */
 195   time (&work->create);
 196   uidwork = &uidtbl[pwd->pw_uid % modulo];
 197   if (uidwork->pwptr == NULL)
 198     uidwork->pwptr = work->pwd;
 199   else
 200    {
 201       while (uidwork->next != NULL)
 202         uidwork = uidwork->next;
 203
 204       uidwork->next = calloc (1, sizeof (uidhash));
 205       uidwork->next->pwptr = work->pwd;
 206     }
 207   return 0;
 208 }
 209
 210 static struct passwd *
 211 cache_search_name (const char *name)
 212 {
 213   pwdhash *work;
 214   unsigned long int hash = __nis_hash (name, strlen (name)) % modulo;
 215
 216   work = &pwdtbl[hash];
 217
 218   while (work->pwd != NULL)
 219     {
 220       if (strcmp (work->pwd->pw_name, name) == 0)
 221         return work->pwd;
 222       if (work->next != NULL)
 223         work = work->next;
 224       else
 225         return NULL;
 226     }
 227   return NULL;
 228 }
 229
 230 static struct passwd *
 231 cache_search_uid (uid_t uid)
 232 {
 233   uidhash *work;
 234
 235   work = &uidtbl[uid % modulo];
 236
 237   while (work->pwptr != NULL)
 238     {
 239       if (work->pwptr->pw_uid == uid)
 240         return work->pwptr;
 241       if (work->next != NULL)
 242         work = work->next;
 243       else
 244         return NULL;
 245     }
 246   return NULL;
 247 }
 248
 249 static int
 250 add_negcache (char *key)
 251 {
 252   neghash *work;
 253   unsigned long int hash = __nis_hash (key, strlen (key)) % modulo;
 254
 255   if (debug_flag)
 256     dbg_log (_("pwd_add_netgache (%s|%ld)"), key, hash);
 257
 258   work = &negtbl[hash];
 259
 260   if (negtbl[hash].key == NULL)
 261     {
 262       negtbl[hash].key = strdup (key);
 263       negtbl[hash].next = NULL;
 264     }
 265   else
 266     {
 267       while (work->next != NULL)
 268         work = work->next;
 269
 270       work->next = calloc (1, sizeof (neghash));
 271       work->next->key = strdup (key);
 272       work = work->next;
 273     }
 274
 275   time (&work->create);
 276
 277   return 0;
 278 }
 279
 280 static int
 281 cache_search_neg (const char *key)
 282 {
 283   neghash *work;
 284   unsigned long int hash = __nis_hash (key, strlen (key)) % modulo;
 285
 286   if (debug_flag)
 287     dbg_log (_("pwd_cache_search_neg (%s|%ld)"), key, hash);
 288
 289   work = &negtbl[hash];
 290
 291   while (work->key != NULL)
 292     {
 293       if (strcmp (work->key, key) == 0)
 294         return 1;
 295       if (work->next != NULL)
 296         work = work->next;
 297       else
 298         return 0;
 299     }
 300   return 0;
 301 }
 302
 303 void *
 304 cache_getpwnam (void *v_param)
 305 {
 306   struct passwd *pwd;
 307   param_t *param = (param_t *)v_param;
 308
 309   pthread_rwlock_rdlock (&pwdlock);
 310   pwd = cache_search_name (param->key);
 311
 312   /* I don't like it to hold the read only lock longer, but it is
 313      necessary to avoid to much malloc/free/strcpy.  */
 314
 315   if (pwd != NULL)
 316     {
 317       if (debug_flag)
 318         dbg_log (_("Found \"%s\" in cache !"), param->key);
 319
 320       ++poshit;
 321       pw_send_answer (param->conn, pwd);
 322       close_socket (param->conn);
 323
 324       pthread_rwlock_unlock (&pwdlock);
 325     }
 326   else
 327     {
 328       int status;
 329       int buflen = 1024;
 330       char *buffer = calloc (1, buflen);
 331       struct passwd resultbuf;
 332
 333       if (debug_flag)
 334         dbg_log (_("Doesn't found \"%s\" in cache !"), param->key);
 335
 336       pthread_rwlock_unlock (&pwdlock);
 337
 338       pthread_rwlock_rdlock (&neglock);
 339       status = cache_search_neg (param->key);
 340       pthread_rwlock_unlock (&neglock);
 341
 342       if (status == 0)
 343         {
 344           while (buffer != NULL
 345                  && (getpwnam_r (param->key, &resultbuf, buffer, buflen, &pwd)
 346                      != 0)
 347                  && errno == ERANGE)
 348             {
 349               errno = 0;
 350               buflen += 1024;
 351               buffer = realloc (buffer, buflen);
 352             }
 353
 354           if (buffer != NULL && pwd != NULL)
 355             {
 356               struct passwd *tmp;
 357
 358               ++posmiss;
 359               pthread_rwlock_wrlock (&pwdlock);
 360               /* While we are waiting on the lock, somebody else could
 361                  add this entry.  */
 362               tmp = cache_search_name (param->key);
 363               if (tmp == NULL)
 364                 add_cache (pwd);
 365               pthread_rwlock_unlock (&pwdlock);
 366             }
 367           else
 368             {
 369               ++negmiss;
 370               pthread_rwlock_wrlock (&neglock);
 371               add_negcache (param->key);
 372               pthread_rwlock_unlock (&neglock);
 373             }
 374         }
 375       else
 376         ++neghit;
 377       pw_send_answer (param->conn, pwd);
 378       close_socket (param->conn);
 379       if (buffer != NULL)
 380         free (buffer);
 381     }
 382   free (param->key);
 383   free (param);
 384   return NULL;
 385 }
 386
 387 void *
 388 cache_pw_disabled (void *v_param)
 389 {
 390   param_t *param = (param_t *)v_param;
 391
 392   if (debug_flag)
 393     dbg_log (_("\tpasswd cache is disabled\n"));
 394
 395   pw_send_disabled (param->conn);
 396   return NULL;
 397 }
 398
 399 void *
 400 cache_getpwuid (void *v_param)
 401 {
 402   param_t *param = (param_t *)v_param;
 403   struct passwd *pwd, resultbuf;
 404   uid_t uid = strtol (param->key, NULL, 10);
 405
 406   pthread_rwlock_rdlock (&pwdlock);
 407   pwd = cache_search_uid (uid);
 408
 409   /* I don't like it to hold the read only lock longer, but it is
 410      necessary to avoid to much malloc/free/strcpy.  */
 411
 412   if (pwd != NULL)
 413     {
 414       if (debug_flag)
 415         dbg_log (_("Found \"%d\" in cache !"), uid);
 416
 417       ++poshit;
 418       pw_send_answer (param->conn, pwd);
 419       close_socket (param->conn);
 420
 421       pthread_rwlock_unlock (&pwdlock);
 422     }
 423   else
 424     {
 425       int buflen = 1024;
 426       char *buffer = malloc (buflen);
 427       int status;
 428
 429       if (debug_flag)
 430         dbg_log (_("Doesn't found \"%d\" in cache !"), uid);
 431
 432       pthread_rwlock_unlock (&pwdlock);
 433
 434       pthread_rwlock_rdlock (&neglock);
 435       status = cache_search_neg (param->key);
 436       pthread_rwlock_unlock (&neglock);
 437
 438       if (status == 0)
 439         {
 440           while (buffer != NULL
 441                  && (getpwuid_r (uid, &resultbuf, buffer, buflen, &pwd) != 0)
 442                  && errno == ERANGE)
 443             {
 444               errno = 0;
 445               buflen += 1024;
 446               buffer = realloc (buffer, buflen);
 447             }
 448
 449           if (buffer != NULL && pwd != NULL)
 450             {
 451               struct passwd *tmp;
 452
 453               ++posmiss;
 454               pthread_rwlock_wrlock (&pwdlock);
 455               /* While we are waiting on the lock, somebody else could
 456                  add this entry.  */
 457               tmp = cache_search_uid (uid);
 458               if (tmp == NULL)
 459                 add_cache (pwd);
 460               pthread_rwlock_unlock (&pwdlock);
 461             }
 462           else
 463             {
 464               ++negmiss;
 465               pthread_rwlock_wrlock (&neglock);
 466               add_negcache (param->key);
 467               pthread_rwlock_unlock (&neglock);
 468             }
 469         }
 470       else
 471         ++neghit;
 472
 473       pw_send_answer (param->conn, pwd);
 474       close_socket (param->conn);
 475       if (buffer != NULL)
 476         free (buffer);
 477     }
 478   free (param->key);
 479   free (param);
 480   return NULL;
 481 }
 482
 483 static void *
 484 pwdtable_update (void *v)
 485 {
 486   time_t now;
 487   int i;
 488
 489   sleep (20);
 490
 491   while (!do_shutdown)
 492     {
 493       if (debug_flag > 2)
 494         dbg_log (_("(pwdtable_update) Wait for write lock!"));
 495
 496       pthread_rwlock_wrlock (&pwdlock);
 497
 498       if (debug_flag > 2)
 499         dbg_log (_("(pwdtable_update) Have write lock"));
 500
 501       time (&now);
 502       for (i = 0; i < modulo; ++i)
 503         {
 504           pwdhash *work = &pwdtbl[i];
 505
 506           while (work && work->pwd)
 507             {
 508               if ((now - work->create) >= postimeout)
 509                 {
 510                   uidhash *uh = &uidtbl[work->pwd->pw_uid % modulo];
 511
 512                   if (debug_flag)
 513                     dbg_log (_("Give \"%s\" free"), work->pwd->pw_name);
 514
 515                   while (uh != NULL && uh->pwptr)
 516                     {
 517                       if (uh->pwptr->pw_uid == work->pwd->pw_uid)
 518                         {
 519                           if (debug_flag)
 520                             dbg_log (_("Give uid for \"%s\" free"),
 521                                      work->pwd->pw_name);
 522                           if (uh->next != NULL)
 523                             {
 524                               uidhash *tmp = uh->next;
 525                               uh->pwptr = tmp->pwptr;
 526                               uh->next = tmp->next;
 527                               free (tmp);
 528                             }
 529                           else
 530                             uh->pwptr = NULL;
 531                         }
 532                       uh = uh->next;
 533                     }
 534
 535                   free_pwd (work->pwd);
 536                   if (work->next != NULL)
 537                     {
 538                       pwdhash *tmp = work->next;
 539                       work->create = tmp->create;
 540                       work->next = tmp->next;
 541                       work->pwd = tmp->pwd;
 542                       free (tmp);
 543                     }
 544                   else
 545                     work->pwd = NULL;
 546                 }
 547               work = work->next;
 548             }
 549         }
 550       if (debug_flag > 2)
 551         dbg_log (_("(pwdtable_update) Release wait lock"));
 552       pthread_rwlock_unlock (&pwdlock);
 553       sleep (20);
 554     }
 555   return NULL;
 556 }
 557
 558 static void *
 559 negtable_update (void *v)
 560 {
 561   time_t now;
 562   int i;
 563
 564   sleep (30);
 565
 566   while (!do_shutdown)
 567     {
 568       if (debug_flag > 2)
 569         dbg_log (_("(negpwdtable_update) Wait for write lock!"));
 570
 571       pthread_rwlock_wrlock (&neglock);
 572
 573       if (debug_flag > 2)
 574         dbg_log (_("(negpwdtable_update) Have write lock"));
 575
 576       time (&now);
 577       for (i = 0; i < modulo; ++i)
 578         {
 579           neghash *work = &negtbl[i];
 580
 581           while (work && work->key)
 582             {
 583               if ((now - work->create) >= negtimeout)
 584                 {
 585                   if (debug_flag)
 586                     dbg_log (_("Give \"%s\" free"), work->key);
 587
 588                   free (work->key);
 589
 590                   if (work->next != NULL)
 591                     {
 592                       neghash *tmp = work->next;
 593                       work->create = tmp->create;
 594                       work->next = tmp->next;
 595                       work->key = tmp->key;
 596                       free (tmp);
 597                     }
 598                   else
 599                     work->key = NULL;
 600                 }
 601               work = work->next;
 602             }
 603         }
 604       if (debug_flag > 2)
 605         dbg_log (_("(negpwdtable_update) Release wait lock"));
 606
 607       pthread_rwlock_unlock (&neglock);
 608       sleep (10);
 609     }
 610   return NULL;
 611 }