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getusershell.c revision 1.23
      1 /*	$NetBSD: getusershell.c,v 1.23 2003/08/07 16:42:51 agc 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)getusershell.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: getusershell.c,v 1.23 2003/08/07 16:42:51 agc Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include "namespace.h"
     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 <stdarg.h>
     50 #include <stdio.h>
     51 #include <stdlib.h>
     52 #include <string.h>
     53 #include <stringlist.h>
     54 #include <unistd.h>
     55 
     56 #ifdef HESIOD
     57 #include <hesiod.h>
     58 #endif
     59 #ifdef YP
     60 #include <rpc/rpc.h>
     61 #include <rpcsvc/ypclnt.h>
     62 #include <rpcsvc/yp_prot.h>
     63 #endif
     64 
     65 #ifdef __weak_alias
     66 __weak_alias(endusershell,_endusershell)
     67 __weak_alias(getusershell,_getusershell)
     68 __weak_alias(setusershell,_setusershell)
     69 #endif
     70 
     71 /*
     72  * Local shells should NOT be added here.  They should be added in
     73  * /etc/shells.
     74  */
     75 
     76 static const char *const okshells[] = { _PATH_BSHELL, _PATH_CSHELL, NULL };
     77 static const char *const *curshell;
     78 static StringList	 *sl;
     79 
     80 static const char *const *initshells __P((void));
     81 
     82 /*
     83  * Get a list of shells from "shells" nsswitch database
     84  */
     85 __aconst char *
     86 getusershell()
     87 {
     88 	__aconst char *ret;
     89 
     90 	if (curshell == NULL)
     91 		curshell = initshells();
     92 	/*LINTED*/
     93 	ret = (__aconst char *)*curshell;
     94 	if (ret != NULL)
     95 		curshell++;
     96 	return (ret);
     97 }
     98 
     99 void
    100 endusershell()
    101 {
    102 	if (sl)
    103 		sl_free(sl, 1);
    104 	sl = NULL;
    105 	curshell = NULL;
    106 }
    107 
    108 void
    109 setusershell()
    110 {
    111 
    112 	curshell = initshells();
    113 }
    114 
    115 
    116 static int	_local_initshells __P((void *, void *, va_list));
    117 
    118 /*ARGSUSED*/
    119 static int
    120 _local_initshells(rv, cb_data, ap)
    121 	void	*rv;
    122 	void	*cb_data;
    123 	va_list	 ap;
    124 {
    125 	char	*sp, *cp;
    126 	FILE	*fp;
    127 	char	 line[MAXPATHLEN + 2];
    128 
    129 	if (sl)
    130 		sl_free(sl, 1);
    131 	sl = sl_init();
    132 	if (!sl)
    133 		return (NS_UNAVAIL);
    134 
    135 	if ((fp = fopen(_PATH_SHELLS, "r")) == NULL)
    136 		return (NS_UNAVAIL);
    137 
    138 	sp = cp = line;
    139 	while (fgets(cp, MAXPATHLEN + 1, fp) != NULL) {
    140 		while (*cp != '#' && *cp != '/' && *cp != '\0')
    141 			cp++;
    142 		if (*cp == '#' || *cp == '\0')
    143 			continue;
    144 		sp = cp;
    145 		while (!isspace((unsigned char) *cp) && *cp != '#'
    146 		    && *cp != '\0')
    147 			cp++;
    148 		*cp++ = '\0';
    149 		if (sl_add(sl, strdup(sp)) == -1)
    150 			return (NS_UNAVAIL);
    151 	}
    152 	(void)fclose(fp);
    153 	return (NS_SUCCESS);
    154 }
    155 
    156 #ifdef HESIOD
    157 static int	_dns_initshells __P((void *, void *, va_list));
    158 
    159 /*ARGSUSED*/
    160 static int
    161 _dns_initshells(rv, cb_data, ap)
    162 	void	*rv;
    163 	void	*cb_data;
    164 	va_list	 ap;
    165 {
    166 	char	  shellname[] = "shells-XXXXX";
    167 	int	  hsindex, hpi, r;
    168 	char	**hp;
    169 	void	 *context;
    170 
    171 	if (sl)
    172 		sl_free(sl, 1);
    173 	sl = sl_init();
    174 	if (!sl)
    175 		return (NS_UNAVAIL);
    176 
    177 	r = NS_UNAVAIL;
    178 	if (hesiod_init(&context) == -1)
    179 		return (r);
    180 
    181 	for (hsindex = 0; ; hsindex++) {
    182 		snprintf(shellname, sizeof(shellname)-1, "shells-%d", hsindex);
    183 		hp = hesiod_resolve(context, shellname, "shells");
    184 		if (hp == NULL) {
    185 			if (errno == ENOENT) {
    186 				if (hsindex == 0)
    187 					r = NS_NOTFOUND;
    188 				else
    189 					r = NS_SUCCESS;
    190 			}
    191 			break;
    192 		} else {
    193 			int bad = 0;
    194 
    195 			for (hpi = 0; hp[hpi]; hpi++)
    196 				if (sl_add(sl, hp[hpi]) == -1) {
    197 					bad = 1;
    198 					break;
    199 				}
    200 			free(hp);
    201 			if (bad)
    202 				break;
    203 		}
    204 	}
    205 	hesiod_end(context);
    206 	return (r);
    207 }
    208 #endif /* HESIOD */
    209 
    210 #ifdef YP
    211 static int	_nis_initshells __P((void *, void *, va_list));
    212 
    213 /*ARGSUSED*/
    214 static int
    215 _nis_initshells(rv, cb_data, ap)
    216 	void	*rv;
    217 	void	*cb_data;
    218 	va_list	 ap;
    219 {
    220 	static char *ypdomain;
    221 
    222 	if (sl)
    223 		sl_free(sl, 1);
    224 	sl = sl_init();
    225 	if (!sl)
    226 		return (NS_UNAVAIL);
    227 
    228 	if (ypdomain == NULL) {
    229 		switch (yp_get_default_domain(&ypdomain)) {
    230 		case 0:
    231 			break;
    232 		case YPERR_RESRC:
    233 			return (NS_TRYAGAIN);
    234 		default:
    235 			return (NS_UNAVAIL);
    236 		}
    237 	}
    238 
    239 	for (;;) {
    240 		char	*ypcur = NULL;
    241 		int	 ypcurlen = 0;	/* XXX: GCC */
    242 		char	*key, *data;
    243 		int	 keylen, datalen;
    244 		int	 r;
    245 
    246 		key = data = NULL;
    247 		if (ypcur) {
    248 			r = yp_next(ypdomain, "shells", ypcur, ypcurlen,
    249 					&key, &keylen, &data, &datalen);
    250 			free(ypcur);
    251 			switch (r) {
    252 			case 0:
    253 				break;
    254 			case YPERR_NOMORE:
    255 				free(key);
    256 				free(data);
    257 				return (NS_SUCCESS);
    258 			default:
    259 				free(key);
    260 				free(data);
    261 				return (NS_UNAVAIL);
    262 			}
    263 			ypcur = key;
    264 			ypcurlen = keylen;
    265 		} else {
    266 			if (yp_first(ypdomain, "shells", &ypcur,
    267 				    &ypcurlen, &data, &datalen)) {
    268 				free(data);
    269 				return (NS_UNAVAIL);
    270 			}
    271 		}
    272 		data[datalen] = '\0';		/* clear trailing \n */
    273 		if (sl_add(sl, data) == -1)
    274 			return (NS_UNAVAIL);
    275 	}
    276 }
    277 #endif /* YP */
    278 
    279 static const char *const *
    280 initshells()
    281 {
    282 	static const ns_dtab dtab[] = {
    283 		NS_FILES_CB(_local_initshells, NULL)
    284 		NS_DNS_CB(_dns_initshells, NULL)
    285 		NS_NIS_CB(_nis_initshells, NULL)
    286 		{ 0 }
    287 	};
    288 	if (sl)
    289 		sl_free(sl, 1);
    290 	sl = sl_init();
    291 	if (!sl)
    292 		goto badinitshells;
    293 
    294 	if (nsdispatch(NULL, dtab, NSDB_SHELLS, "initshells", __nsdefaultsrc)
    295 	    != NS_SUCCESS) {
    296  badinitshells:
    297 		if (sl)
    298 			sl_free(sl, 1);
    299 		sl = NULL;
    300 		return (okshells);
    301 	}
    302 	if (sl_add(sl, NULL) == -1)
    303 		goto badinitshells;
    304 
    305 	return (const char *const *)(sl->sl_str);
    306 }
    307