getusershell.c revision 65532 
1/*	$NetBSD: getusershell.c,v 1.17 1999/01/25 01:09:34 lukem Exp $	*/
2
3/*
4 * Copyright (c) 1985, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. 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#include <sys/cdefs.h>
37#if defined(LIBC_SCCS) && !defined(lint)
38static char rcsid[] =
39  "$FreeBSD: head/lib/libc/gen/getusershell.c 65532 2000-09-06 18:16:48Z nectar $";
40#endif /* LIBC_SCCS and not lint */
41
42#include <sys/param.h>
43#include <sys/file.h>
44
45#include <ctype.h>
46#include <errno.h>
47#include <nsswitch.h>
48#include <paths.h>
49#include <stdio.h>
50#include <stdlib.h>
51#include <string.h>
52#include <stringlist.h>
53#include <unistd.h>
54
55#ifdef HESIOD
56#include <hesiod.h>
57#endif
58#ifdef YP
59#include <rpc/rpc.h>
60#include <rpcsvc/ypclnt.h>
61#include <rpcsvc/yp_prot.h>
62#endif
63
64/*
65 * Local shells should NOT be added here.  They should be added in
66 * /etc/shells.
67 */
68
69static const char *const okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
70static const char *const *curshell;
71static StringList	 *sl;
72
73static const char *const *initshells __P((void));
74
75/*
76 * Get a list of shells from "shells" nsswitch database
77 */
78char *
79getusershell(void)
80{
81	char *ret;
82
83	if (curshell == NULL)
84		curshell = initshells();
85	/*LINTED*/
86	ret = (char *)*curshell;
87	if (ret != NULL)
88		curshell++;
89	return (ret);
90}
91
92void
93endusershell(void)
94{
95	if (sl)
96		sl_free(sl, 1);
97	sl = NULL;
98	curshell = NULL;
99}
100
101void
102setusershell(void)
103{
104
105	curshell = initshells();
106}
107
108
109static int	_local_initshells __P((void *, void *, va_list));
110
111/*ARGSUSED*/
112static int
113_local_initshells(rv, cb_data, ap)
114	void	*rv;
115	void	*cb_data;
116	va_list	 ap;
117{
118	char	*sp, *cp;
119	FILE	*fp;
120	char	 line[MAXPATHLEN + 2];
121
122	if (sl)
123		sl_free(sl, 1);
124	sl = sl_init();
125
126	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
127		return NS_UNAVAIL;
128
129	sp = cp = line;
130	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
131		while (*cp != '#' && *cp != '/' && *cp != '\0')
132			cp++;
133		if (*cp == '#' || *cp == '\0')
134			continue;
135		sp = cp;
136		while (!isspace(*cp) && *cp != '#' && *cp != '\0')
137			cp++;
138		*cp++ = '\0';
139		sl_add(sl, strdup(sp));
140	}
141	(void)fclose(fp);
142	return NS_SUCCESS;
143}
144
145#ifdef HESIOD
146static int	_dns_initshells __P((void *, void *, va_list));
147
148/*ARGSUSED*/
149static int
150_dns_initshells(rv, cb_data, ap)
151	void	*rv;
152	void	*cb_data;
153	va_list	 ap;
154{
155	char	  shellname[] = "shells-XXXXX";
156	int	  hsindex, hpi, r;
157	char	**hp;
158	void	 *context;
159
160	if (sl)
161		sl_free(sl, 1);
162	sl = sl_init();
163	r = NS_UNAVAIL;
164	if (hesiod_init(&context) == -1)
165		return (r);
166
167	for (hsindex = 0; ; hsindex++) {
168		snprintf(shellname, sizeof(shellname)-1, "shells-%d", hsindex);
169		hp = hesiod_resolve(context, shellname, "shells");
170		if (hp == NULL) {
171			if (errno == ENOENT) {
172				if (hsindex == 0)
173					r = NS_NOTFOUND;
174				else
175					r = NS_SUCCESS;
176			}
177			break;
178		} else {
179			for (hpi = 0; hp[hpi]; hpi++)
180				sl_add(sl, hp[hpi]);
181			free(hp);
182		}
183	}
184	hesiod_end(context);
185	return (r);
186}
187#endif /* HESIOD */
188
189#ifdef YP
190static int	_nis_initshells __P((void *, void *, va_list));
191
192/*ARGSUSED*/
193static int
194_nis_initshells(rv, cb_data, ap)
195	void	*rv;
196	void	*cb_data;
197	va_list	 ap;
198{
199	static char *ypdomain;
200
201	if (sl)
202		sl_free(sl, 1);
203	sl = sl_init();
204
205	if (ypdomain == NULL) {
206		switch (yp_get_default_domain(&ypdomain)) {
207		case 0:
208			break;
209		case YPERR_RESRC:
210			return NS_TRYAGAIN;
211		default:
212			return NS_UNAVAIL;
213		}
214	}
215
216	for (;;) {
217		char	*ypcur = NULL;
218		int	 ypcurlen = 0;	/* XXX: GCC */
219		char	*key, *data;
220		int	 keylen, datalen;
221		int	 r;
222
223		key = data = NULL;
224		if (ypcur) {
225			r = yp_next(ypdomain, "shells", ypcur, ypcurlen,
226					&key, &keylen, &data, &datalen);
227			free(ypcur);
228			switch (r) {
229			case 0:
230				break;
231			case YPERR_NOMORE:
232				free(key);
233				free(data);
234				return NS_SUCCESS;
235			default:
236				free(key);
237				free(data);
238				return NS_UNAVAIL;
239			}
240			ypcur = key;
241			ypcurlen = keylen;
242		} else {
243			if (yp_first(ypdomain, "shells", &ypcur,
244				    &ypcurlen, &data, &datalen)) {
245				free(data);
246				return NS_UNAVAIL;
247			}
248		}
249		data[datalen] = '\0';		/* clear trailing \n */
250		sl_add(sl, data);
251	}
252}
253#endif /* YP */
254
255static const char *const *
256initshells()
257{
258	static const ns_dtab dtab[] = {
259		NS_FILES_CB(_local_initshells, NULL)
260		NS_DNS_CB(_dns_initshells, NULL)
261		NS_NIS_CB(_nis_initshells, NULL)
262		{ 0 }
263	};
264	if (sl)
265		sl_free(sl, 1);
266	sl = sl_init();
267
268	if (nsdispatch(NULL, dtab, NSDB_SHELLS, "initshells", __nsdefaultsrc)
269	    != NS_SUCCESS) {
270		if (sl)
271			sl_free(sl, 1);
272		sl = NULL;
273		return (okshells);
274	}
275	sl_add(sl, NULL);
276
277	return (const char *const *)(sl->sl_str);
278}
279