lib/libc/gen/getusershell.c

   1 /*      $NetBSD: getusershell.c,v 1.26 2006/10/15 16:14:46 christos Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1999, 2005 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Luke Mewburn.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Copyright (c) 1985, 1993
  34  *      The Regents of the University of California.  All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 #include <sys/cdefs.h>
  62 #if defined(LIBC_SCCS) && !defined(lint)
  63 #if 0
  64 static char sccsid[] = "@(#)getusershell.c      8.1 (Berkeley) 6/4/93";
  65 #else
  66 __RCSID("$NetBSD: getusershell.c,v 1.26 2006/10/15 16:14:46 christos Exp $");
  67 #endif
  68 #endif /* LIBC_SCCS and not lint */
  69
  70 #include "namespace.h"
  71 #include "reentrant.h"
  72
  73 #include <sys/param.h>
  74 #include <sys/file.h>
  75
  76 #include <assert.h>
  77 #include <ctype.h>
  78 #include <errno.h>
  79 #include <nsswitch.h>
  80 #include <paths.h>
  81 #include <stdarg.h>
  82 #include <stdio.h>
  83 #include <stdlib.h>
  84 #include <string.h>
  85 #include <unistd.h>
  86
  87 #ifdef HESIOD
  88 #include <hesiod.h>
  89 #endif
  90 #ifdef YP
  91 #include <rpc/rpc.h>
  92 #include <rpcsvc/ypclnt.h>
  93 #include <rpcsvc/yp_prot.h>
  94 #endif
  95
  96 #ifdef __weak_alias
  97 __weak_alias(endusershell,_endusershell)
  98 __weak_alias(getusershell,_getusershell)
  99 __weak_alias(setusershell,_setusershell)
 100 #endif
 101
 102 /*
 103  * Local shells should NOT be added here.
 104  * They should be added in /etc/shells.
 105  */
 106 static const char *const okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
 107
 108 #ifdef _REENTRANT
 109 static mutex_t __shellmutex = MUTEX_INITIALIZER;
 110 #endif
 111
 112 static char               curshell[MAXPATHLEN + 2];
 113
 114 static const char *const *curokshell = okshells;
 115 static int                shellsfound = 0;
 116
 117                 /*
 118                  *      files methods
 119                  */
 120
 121         /* state shared between files methods */
 122 struct files_state {
 123         FILE    *fp;
 124 };
 125
 126 static struct files_state _files_state;
 127
 128
 129 static int
 130 _files_start(struct files_state *state)
 131 {
 132
 133         _DIAGASSERT(state != NULL);
 134
 135         if (state->fp == NULL) {
 136                 state->fp = fopen(_PATH_SHELLS, "r");
 137                 if (state->fp == NULL)
 138                         return NS_UNAVAIL;
 139         } else {
 140                 rewind(state->fp);
 141         }
 142         return NS_SUCCESS;
 143 }
 144
 145 static int
 146 _files_end(struct files_state *state)
 147 {
 148
 149         _DIAGASSERT(state != NULL);
 150
 151         if (state->fp) {
 152                 (void) fclose(state->fp);
 153                 state->fp = NULL;
 154         }
 155         return NS_SUCCESS;
 156 }
 157
 158 /*ARGSUSED*/
 159 static int
 160 _files_setusershell(void *nsrv, void *nscb, va_list ap)
 161 {
 162
 163         return _files_start(&_files_state);
 164 }
 165
 166 /*ARGSUSED*/
 167 static int
 168 _files_endusershell(void *nsrv, void *nscb, va_list ap)
 169 {
 170
 171         return _files_end(&_files_state);
 172 }
 173
 174 /*ARGSUSED*/
 175 static int
 176 _files_getusershell(void *nsrv, void *nscb, va_list ap)
 177 {
 178         char    **retval = va_arg(ap, char **);
 179
 180         char    *sp, *cp;
 181         int      rv;
 182
 183         _DIAGASSERT(retval != NULL);
 184
 185         *retval = NULL;
 186         if (_files_state.fp == NULL) {  /* only start if file not open yet */
 187                 rv = _files_start(&_files_state);
 188                 if (rv != NS_SUCCESS)
 189                         return rv;
 190         }
 191
 192         while (fgets(curshell, sizeof(curshell) - 1, _files_state.fp) != NULL) {
 193                 sp = cp = curshell;
 194                 while (*cp != '#' && *cp != '/' && *cp != '\0')
 195                         cp++;
 196                 if (*cp == '#' || *cp == '\0')
 197                         continue;
 198                 sp = cp;
 199                 while (!isspace((unsigned char) *cp) && *cp != '#'
 200                     && *cp != '\0')
 201                         cp++;
 202                 *cp++ = '\0';
 203                 *retval = sp;
 204                 return NS_SUCCESS;
 205         }
 206
 207         return NS_NOTFOUND;
 208 }
 209
 210
 211 #ifdef HESIOD
 212                 /*
 213                  *      dns methods
 214                  */
 215
 216         /* state shared between dns methods */
 217 struct dns_state {
 218         void    *context;               /* Hesiod context */
 219         int      num;                   /* shell index, -1 if no more */
 220 };
 221
 222 static struct dns_state         _dns_state;
 223
 224 static int
 225 _dns_start(struct dns_state *state)
 226 {
 227
 228         _DIAGASSERT(state != NULL);
 229
 230         state->num = 0;
 231         if (state->context == NULL) {                   /* setup Hesiod */
 232                 if (hesiod_init(&state->context) == -1)
 233                         return NS_UNAVAIL;
 234         }
 235
 236         return NS_SUCCESS;
 237 }
 238
 239 static int
 240 _dns_end(struct dns_state *state)
 241 {
 242
 243         _DIAGASSERT(state != NULL);
 244
 245         state->num = 0;
 246         if (state->context) {
 247                 hesiod_end(state->context);
 248                 state->context = NULL;
 249         }
 250         return NS_SUCCESS;
 251 }
 252
 253 /*ARGSUSED*/
 254 static int
 255 _dns_setusershell(void *nsrv, void *nscb, va_list ap)
 256 {
 257
 258         return _dns_start(&_dns_state);
 259 }
 260
 261 /*ARGSUSED*/
 262 static int
 263 _dns_endusershell(void *nsrv, void *nscb, va_list ap)
 264 {
 265
 266         return _dns_end(&_dns_state);
 267 }
 268
 269 /*ARGSUSED*/
 270 static int
 271 _dns_getusershell(void *nsrv, void *nscb, va_list ap)
 272 {
 273         char    **retval = va_arg(ap, char **);
 274
 275         char      shellname[] = "shells-NNNNNNNNNN";
 276         char    **hp, *ep;
 277         int       rv;
 278
 279         _DIAGASSERT(retval != NULL);
 280
 281         *retval = NULL;
 282
 283         if (_dns_state.num == -1)                       /* exhausted search */
 284                 return NS_NOTFOUND;
 285
 286         if (_dns_state.context == NULL) {
 287                         /* only start if Hesiod not setup */
 288                 rv = _dns_start(&_dns_state);
 289                 if (rv != NS_SUCCESS)
 290                         return rv;
 291         }
 292
 293         hp = NULL;
 294         rv = NS_NOTFOUND;
 295
 296                                                         /* find shells-NNN */
 297         snprintf(shellname, sizeof(shellname), "shells-%d", _dns_state.num);
 298         _dns_state.num++;
 299
 300         hp = hesiod_resolve(_dns_state.context, shellname, "shells");
 301         if (hp == NULL) {
 302                 if (errno == ENOENT)
 303                         rv = NS_NOTFOUND;
 304                 else
 305                         rv = NS_UNAVAIL;
 306         } else {
 307                 if ((ep = strchr(hp[0], '\n')) != NULL)
 308                         *ep = '\0';                     /* clear trailing \n */
 309                                                 /* only use first result */
 310                 strlcpy(curshell, hp[0], sizeof(curshell));
 311                 *retval = curshell;
 312                 rv = NS_SUCCESS;
 313         }
 314
 315         if (hp)
 316                 hesiod_free_list(_dns_state.context, hp);
 317         if (rv != NS_SUCCESS)
 318                 _dns_state.num = -1;            /* any failure halts search */
 319         return rv;
 320 }
 321
 322 #endif /* HESIOD */
 323
 324
 325 #ifdef YP
 326                 /*
 327                  *      nis methods
 328                  */
 329         /* state shared between nis methods */
 330 struct nis_state {
 331         char            *domain;        /* NIS domain */
 332         int              done;          /* non-zero if search exhausted */
 333         char            *current;       /* current first/next match */
 334         int              currentlen;    /* length of _nis_current */
 335 };
 336
 337 static struct nis_state         _nis_state;
 338
 339 static int
 340 _nis_start(struct nis_state *state)
 341 {
 342
 343         _DIAGASSERT(state != NULL);
 344
 345         state->done = 0;
 346         if (state->current) {
 347                 free(state->current);
 348                 state->current = NULL;
 349         }
 350         if (state->domain == NULL) {                    /* setup NIS */
 351                 switch (yp_get_default_domain(&state->domain)) {
 352                 case 0:
 353                         break;
 354                 case YPERR_RESRC:
 355                         return NS_TRYAGAIN;
 356                 default:
 357                         return NS_UNAVAIL;
 358                 }
 359         }
 360         return NS_SUCCESS;
 361 }
 362
 363 static int
 364 _nis_end(struct nis_state *state)
 365 {
 366
 367         _DIAGASSERT(state != NULL);
 368
 369         if (state->domain)
 370                 state->domain = NULL;
 371         state->done = 0;
 372         if (state->current)
 373                 free(state->current);
 374         state->current = NULL;
 375         return NS_SUCCESS;
 376 }
 377
 378 /*ARGSUSED*/
 379 static int
 380 _nis_setusershell(void *nsrv, void *nscb, va_list ap)
 381 {
 382
 383         return _nis_start(&_nis_state);
 384 }
 385
 386 /*ARGSUSED*/
 387 static int
 388 _nis_endusershell(void *nsrv, void *nscb, va_list ap)
 389 {
 390
 391         return _nis_end(&_nis_state);
 392 }
 393
 394 /*ARGSUSED*/
 395 static int
 396 _nis_getusershell(void *nsrv, void *nscb, va_list ap)
 397 {
 398         char    **retval = va_arg(ap, char **);
 399
 400         char    *key, *data;
 401         int     keylen, datalen, rv, nisr;
 402
 403         _DIAGASSERT(retval != NULL);
 404
 405         *retval = NULL;
 406
 407         if (_nis_state.done)                            /* exhausted search */
 408                 return NS_NOTFOUND;
 409         if (_nis_state.domain == NULL) {
 410                                         /* only start if NIS not setup */
 411                 rv = _nis_start(&_nis_state);
 412                 if (rv != NS_SUCCESS)
 413                         return rv;
 414         }
 415
 416         key = NULL;
 417         data = NULL;
 418         rv = NS_NOTFOUND;
 419
 420         if (_nis_state.current) {                       /* already searching */
 421                 nisr = yp_next(_nis_state.domain, "shells",
 422                     _nis_state.current, _nis_state.currentlen,
 423                     &key, &keylen, &data, &datalen);
 424                 free(_nis_state.current);
 425                 _nis_state.current = NULL;
 426                 switch (nisr) {
 427                 case 0:
 428                         _nis_state.current = key;
 429                         _nis_state.currentlen = keylen;
 430                         key = NULL;
 431                         break;
 432                 case YPERR_NOMORE:
 433                         rv = NS_NOTFOUND;
 434                         goto nisent_out;
 435                 default:
 436                         rv = NS_UNAVAIL;
 437                         goto nisent_out;
 438                 }
 439         } else {                                        /* new search */
 440                 if (yp_first(_nis_state.domain, "shells",
 441                     &_nis_state.current, &_nis_state.currentlen,
 442                     &data, &datalen)) {
 443                         rv = NS_UNAVAIL;
 444                         goto nisent_out;
 445                 }
 446         }
 447
 448         data[datalen] = '\0';                           /* clear trailing \n */
 449         strlcpy(curshell, data, sizeof(curshell));
 450         *retval = curshell;
 451         rv = NS_SUCCESS;
 452
 453  nisent_out:
 454         if (key)
 455                 free(key);
 456         if (data)
 457                 free(data);
 458         if (rv != NS_SUCCESS)                   /* any failure halts search */
 459                 _nis_state.done = 1;
 460         return rv;
 461 }
 462
 463 #endif /* YP */
 464
 465
 466                 /*
 467                  *      public functions
 468                  */
 469
 470 void
 471 endusershell(void)
 472 {
 473         static const ns_dtab dtab[] = {
 474                 NS_FILES_CB(_files_endusershell, NULL)
 475                 NS_DNS_CB(_dns_endusershell, NULL)
 476                 NS_NIS_CB(_nis_endusershell, NULL)
 477                 NS_NULL_CB
 478         };
 479
 480         mutex_lock(&__shellmutex);
 481
 482         curokshell = okshells;          /* reset okshells fallback state */
 483         shellsfound = 0;
 484
 485                                         /* force all endusershell() methods */
 486         (void) nsdispatch(NULL, dtab, NSDB_SHELLS, "endusershell",
 487             __nsdefaultfiles_forceall);
 488         mutex_unlock(&__shellmutex);
 489 }
 490
 491 __aconst char *
 492 getusershell(void)
 493 {
 494         int              rv;
 495         __aconst char   *retval;
 496
 497         static const ns_dtab dtab[] = {
 498                 NS_FILES_CB(_files_getusershell, NULL)
 499                 NS_DNS_CB(_dns_getusershell, NULL)
 500                 NS_NIS_CB(_nis_getusershell, NULL)
 501                 NS_NULL_CB
 502         };
 503
 504         mutex_lock(&__shellmutex);
 505
 506         retval = NULL;
 507         do {
 508                 rv = nsdispatch(NULL, dtab, NSDB_SHELLS, "getusershell",
 509                     __nsdefaultsrc, &retval);
 510                                 /* loop until failure or non-blank result */
 511         } while (rv == NS_SUCCESS && retval[0] == '\0');
 512
 513         if (rv == NS_SUCCESS) {
 514                 shellsfound++;
 515         } else if (shellsfound == 0) {  /* no shells; fall back to okshells */
 516                 if (curokshell != NULL) {
 517                         retval = __UNCONST(*curokshell);
 518                         curokshell++;
 519                         rv = NS_SUCCESS;
 520                 }
 521         }
 522
 523         mutex_unlock(&__shellmutex);
 524         return (rv == NS_SUCCESS) ? retval : NULL;
 525 }
 526
 527 void
 528 setusershell(void)
 529 {
 530         static const ns_dtab dtab[] = {
 531                 NS_FILES_CB(_files_setusershell, NULL)
 532                 NS_DNS_CB(_dns_setusershell, NULL)
 533                 NS_NIS_CB(_nis_setusershell, NULL)
 534                 NS_NULL_CB
 535         };
 536
 537         mutex_lock(&__shellmutex);
 538
 539         curokshell = okshells;          /* reset okshells fallback state */
 540         shellsfound = 0;
 541
 542                                         /* force all setusershell() methods */
 543         (void) nsdispatch(NULL, dtab, NSDB_SHELLS, "setusershell",
 544             __nsdefaultfiles_forceall);
 545         mutex_unlock(&__shellmutex);
 546 }