1/* $NetBSD: getusershell.c,v 1.29 2012/03/13 21:13:36 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
64static char sccsid[] = "@(#)getusershell.c 8.1 (Berkeley) 6/4/93";
65#else
66__RCSID("$NetBSD: getusershell.c,v 1.29 2012/03/13 21:13:36 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 */
106static const char *const okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
107
108#ifdef _REENTRANT
109static mutex_t __shellmutex = MUTEX_INITIALIZER;
110#endif
111
112static char curshell[MAXPATHLEN + 2];
113
114static const char *const *curokshell = okshells;
115static int shellsfound = 0;
116
117 /*
118 * files methods
119 */
120
121 /* state shared between files methods */
122struct files_state {
123 FILE *fp;
124};
125
126static struct files_state _files_state;
127
128
129static 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, "re");
137 if (state->fp == NULL)
138 return NS_UNAVAIL;
139 } else {
140 rewind(state->fp);
141 }
142 return NS_SUCCESS;
143}
144
145static 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*/
159static int
160_files_setusershell(void *nsrv, void *nscb, va_list ap)
161{
162
163 return _files_start(&_files_state);
164}
165
166/*ARGSUSED*/
167static int
168_files_endusershell(void *nsrv, void *nscb, va_list ap)
169{
170
171 return _files_end(&_files_state);
172}
173
174/*ARGSUSED*/
175static 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, (int)sizeof(curshell) - 1, _files_state.fp)
193 != NULL) {
194 sp = cp = curshell;
195 while (*cp != '#' && *cp != '/' && *cp != '\0')
196 cp++;
197 if (*cp == '#' || *cp == '\0')
198 continue;
199 sp = cp;
200 while (!isspace((unsigned char) *cp) && *cp != '#'
201 && *cp != '\0')
202 cp++;
203 *cp++ = '\0';
204 *retval = sp;
205 return NS_SUCCESS;
206 }
207
208 return NS_NOTFOUND;
209}
210
211
212#ifdef HESIOD
213 /*
214 * dns methods
215 */
216
217 /* state shared between dns methods */
218struct dns_state {
219 void *context; /* Hesiod context */
220 int num; /* shell index, -1 if no more */
221};
222
223static struct dns_state _dns_state;
224
225static int
226_dns_start(struct dns_state *state)
227{
228
229 _DIAGASSERT(state != NULL);
230
231 state->num = 0;
232 if (state->context == NULL) { /* setup Hesiod */
233 if (hesiod_init(&state->context) == -1)
234 return NS_UNAVAIL;
235 }
236
237 return NS_SUCCESS;
238}
239
240static int
241_dns_end(struct dns_state *state)
242{
243
244 _DIAGASSERT(state != NULL);
245
246 state->num = 0;
247 if (state->context) {
248 hesiod_end(state->context);
249 state->context = NULL;
250 }
251 return NS_SUCCESS;
252}
253
254/*ARGSUSED*/
255static int
256_dns_setusershell(void *nsrv, void *nscb, va_list ap)
257{
258
259 return _dns_start(&_dns_state);
260}
261
262/*ARGSUSED*/
263static int
264_dns_endusershell(void *nsrv, void *nscb, va_list ap)
265{
266
267 return _dns_end(&_dns_state);
268}
269
270/*ARGSUSED*/
271static int
272_dns_getusershell(void *nsrv, void *nscb, va_list ap)
273{
274 char **retval = va_arg(ap, char **);
275
276 char shellname[] = "shells-NNNNNNNNNN";
277 char **hp, *ep;
278 int rv;
279
280 _DIAGASSERT(retval != NULL);
281
282 *retval = NULL;
283
284 if (_dns_state.num == -1) /* exhausted search */
285 return NS_NOTFOUND;
286
287 if (_dns_state.context == NULL) {
288 /* only start if Hesiod not setup */
289 rv = _dns_start(&_dns_state);
290 if (rv != NS_SUCCESS)
291 return rv;
292 }
293
294 hp = NULL;
295 rv = NS_NOTFOUND;
296
297 /* find shells-NNN */
298 snprintf(shellname, sizeof(shellname), "shells-%d", _dns_state.num);
299 _dns_state.num++;
300
301 hp = hesiod_resolve(_dns_state.context, shellname, "shells");
302 if (hp == NULL) {
303 if (errno == ENOENT)
304 rv = NS_NOTFOUND;
305 else
306 rv = NS_UNAVAIL;
307 } else {
308 if ((ep = strchr(hp[0], '\n')) != NULL)
309 *ep = '\0'; /* clear trailing \n */
310 /* only use first result */
311 strlcpy(curshell, hp[0], sizeof(curshell));
312 *retval = curshell;
313 rv = NS_SUCCESS;
314 }
315
316 if (hp)
317 hesiod_free_list(_dns_state.context, hp);
318 if (rv != NS_SUCCESS)
319 _dns_state.num = -1; /* any failure halts search */
320 return rv;
321}
322
323#endif /* HESIOD */
324
325
326#ifdef YP
327 /*
328 * nis methods
329 */
330 /* state shared between nis methods */
331struct nis_state {
332 char *domain; /* NIS domain */
333 int done; /* non-zero if search exhausted */
334 char *current; /* current first/next match */
335 int currentlen; /* length of _nis_current */
336};
337
338static struct nis_state _nis_state;
339
340static int
341_nis_start(struct nis_state *state)
342{
343
344 _DIAGASSERT(state != NULL);
345
346 state->done = 0;
347 if (state->current) {
348 free(state->current);
349 state->current = NULL;
350 }
351 if (state->domain == NULL) { /* setup NIS */
352 switch (yp_get_default_domain(&state->domain)) {
353 case 0:
354 break;
355 case YPERR_RESRC:
356 return NS_TRYAGAIN;
357 default:
358 return NS_UNAVAIL;
359 }
360 }
361 return NS_SUCCESS;
362}
363
364static int
365_nis_end(struct nis_state *state)
366{
367
368 _DIAGASSERT(state != NULL);
369
370 if (state->domain)
371 state->domain = NULL;
372 state->done = 0;
373 if (state->current)
374 free(state->current);
375 state->current = NULL;
376 return NS_SUCCESS;
377}
378
379/*ARGSUSED*/
380static int
381_nis_setusershell(void *nsrv, void *nscb, va_list ap)
382{
383
384 return _nis_start(&_nis_state);
385}
386
387/*ARGSUSED*/
388static int
389_nis_endusershell(void *nsrv, void *nscb, va_list ap)
390{
391
392 return _nis_end(&_nis_state);
393}
394
395/*ARGSUSED*/
396static int
397_nis_getusershell(void *nsrv, void *nscb, va_list ap)
398{
399 char **retval = va_arg(ap, char **);
400
401 char *key, *data;
402 int keylen, datalen, rv, nisr;
403
404 _DIAGASSERT(retval != NULL);
405
406 *retval = NULL;
407
408 if (_nis_state.done) /* exhausted search */
409 return NS_NOTFOUND;
410 if (_nis_state.domain == NULL) {
411 /* only start if NIS not setup */
412 rv = _nis_start(&_nis_state);
413 if (rv != NS_SUCCESS)
414 return rv;
415 }
416
417 key = NULL;
418 data = NULL;
419 rv = NS_NOTFOUND;
420
421 if (_nis_state.current) { /* already searching */
422 nisr = yp_next(_nis_state.domain, "shells",
423 _nis_state.current, _nis_state.currentlen,
424 &key, &keylen, &data, &datalen);
425 free(_nis_state.current);
426 _nis_state.current = NULL;
427 switch (nisr) {
428 case 0:
429 _nis_state.current = key;
430 _nis_state.currentlen = keylen;
431 key = NULL;
432 break;
433 case YPERR_NOMORE:
434 rv = NS_NOTFOUND;
435 goto nisent_out;
436 default:
437 rv = NS_UNAVAIL;
438 goto nisent_out;
439 }
440 } else { /* new search */
441 if (yp_first(_nis_state.domain, "shells",
442 &_nis_state.current, &_nis_state.currentlen,
443 &data, &datalen)) {
444 rv = NS_UNAVAIL;
445 goto nisent_out;
446 }
447 }
448
449 data[datalen] = '\0'; /* clear trailing \n */
450 strlcpy(curshell, data, sizeof(curshell));
451 *retval = curshell;
452 rv = NS_SUCCESS;
453
454 nisent_out:
455 if (key)
456 free(key);
457 if (data)
458 free(data);
459 if (rv != NS_SUCCESS) /* any failure halts search */
460 _nis_state.done = 1;
461 return rv;
462}
463
464#endif /* YP */
465
466
467 /*
468 * public functions
469 */
470
471void
472endusershell(void)
473{
474 static const ns_dtab dtab[] = {
475 NS_FILES_CB(_files_endusershell, NULL)
476 NS_DNS_CB(_dns_endusershell, NULL)
477 NS_NIS_CB(_nis_endusershell, NULL)
478 NS_NULL_CB
479 };
480
481 mutex_lock(&__shellmutex);
482
483 curokshell = okshells; /* reset okshells fallback state */
484 shellsfound = 0;
485
486 /* force all endusershell() methods */
487 (void) nsdispatch(NULL, dtab, NSDB_SHELLS, "endusershell",
488 __nsdefaultfiles_forceall);
489 mutex_unlock(&__shellmutex);
490}
491
492__aconst char *
493getusershell(void)
494{
495 int rv;
496 __aconst char *retval;
497
498 static const ns_dtab dtab[] = {
499 NS_FILES_CB(_files_getusershell, NULL)
500 NS_DNS_CB(_dns_getusershell, NULL)
501 NS_NIS_CB(_nis_getusershell, NULL)
502 NS_NULL_CB
503 };
504
505 mutex_lock(&__shellmutex);
506
507 retval = NULL;
508 do {
509 rv = nsdispatch(NULL, dtab, NSDB_SHELLS, "getusershell",
510 __nsdefaultsrc, &retval);
511 /* loop until failure or non-blank result */
512 } while (rv == NS_SUCCESS && retval[0] == '\0');
513
514 if (rv == NS_SUCCESS) {
515 shellsfound++;
516 } else if (shellsfound == 0) { /* no shells; fall back to okshells */
517 if (curokshell != NULL) {
518 retval = __UNCONST(*curokshell);
519 curokshell++;
520 rv = NS_SUCCESS;
521 }
522 }
523
524 mutex_unlock(&__shellmutex);
525 return (rv == NS_SUCCESS) ? retval : NULL;
526}
527
528void
529setusershell(void)
530{
531 static const ns_dtab dtab[] = {
532 NS_FILES_CB(_files_setusershell, NULL)
533 NS_DNS_CB(_dns_setusershell, NULL)
534 NS_NIS_CB(_nis_setusershell, NULL)
535 NS_NULL_CB
536 };
537
538 mutex_lock(&__shellmutex);
539
540 curokshell = okshells; /* reset okshells fallback state */
541 shellsfound = 0;
542
543 /* force all setusershell() methods */
544 (void) nsdispatch(NULL, dtab, NSDB_SHELLS, "setusershell",
545 __nsdefaultfiles_forceall);
546 mutex_unlock(&__shellmutex);
547}
548