xref: /titanic_41/usr/src/lib/libc/port/gen/getnetgrent.c (revision bd0f52d78d701efcad2c460df61b45677d041c35)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * getnetgrent.c
31  *
32  *	- name-service switch frontend routines for the netgroup API.
33  *
34  * Policy decision:
35  *	If netgroup A refers to netgroup B, both must occur in the same
36  *	source (any other choice gives very confusing semantics).  This
37  *	assumption is deeply embedded in the code below and in the backends.
38  *
39  * innetgr() is implemented on top of something called __multi_innetgr(),
40  * which replaces each (char *) argument of innetgr() with a counted vector
41  * of (char *).  The semantics are the same as an OR of the results of
42  * innetgr() operations on each possible 4-tuple picked from the arguments,
43  * but it's possible to implement some cases more efficiently.  This is
44  * important for mountd, which used to read YP netgroup.byhost directly in
45  * order to determine efficiently whether a given host belonged to any one
46  * of a long list of netgroups.  Wildcarded arguments are indicated by a
47  * count of zero.
48  */
49 
50 #include "synonyms.h"
51 #include <string.h>
52 #include <synch.h>
53 #include <nss_dbdefs.h>
54 #include <mtlib.h>
55 #include <libc.h>
56 
57 static DEFINE_NSS_DB_ROOT(db_root);
58 
59 void
60 _nss_initf_netgroup(p)
61 	nss_db_params_t	*p;
62 {
63 	p->name	= NSS_DBNAM_NETGROUP;
64 	p->default_config = NSS_DEFCONF_NETGROUP;
65 }
66 
67 /*
68  * The netgroup routines aren't quite like the majority of the switch clients.
69  *   innetgr() more-or-less fits the getXXXbyYYY mould, but for the others:
70  *	- setnetgrent("netgroup") is really a getXXXbyYYY routine, i.e. it
71  *	  searches the sources until it finds an entry with the given name.
72  *	  Rather than returning the (potentially large) entry, it simply
73  *	  initializes a cursor, and then...
74  *      - getnetgrent(...) is repeatedly invoked by the user to extract the
75  *	  contents of the entry found by setnetgrent().
76  *	- endnetgrent() is almost like a real endXXXent routine.
77  * The behaviour in NSS was:
78  *  If we were certain that all the backends could provide netgroup information
79  *  in a common form, we could make the setnetgrent() backend return the entire
80  *  entry to the frontend, then implement getnetgrent() and endnetgrent()
81  *  strictly in the frontend (aka here).  But we're not certain, so we won't.
82  * In NSS2:
83  *  Since nscd returns the results, and it is nscd that accumulates
84  *  the results, then we can return the entire result on the setnetgrent.
85  *
86  * NOTE:
87  *	In the SunOS 4.x (YP) version of this code, innetgr() did not
88  *	affect the state of {set,get,end}netgrent().  Somewhere out
89  *	there probably lurks a program that depends on this behaviour,
90  *	so this version (both frontend and backends) had better
91  *	behave the same way.
92  */
93 
94 /* ===> ?? fix "__" name */
95 int
96 __multi_innetgr(ngroup,	pgroup,
97 		nhost,	phost,
98 		nuser,	puser,
99 		ndomain, pdomain)
100 	nss_innetgr_argc	ngroup, nhost, nuser, ndomain;
101 	nss_innetgr_argv	pgroup, phost, puser, pdomain;
102 {
103 	struct nss_innetgr_args	ia;
104 
105 	if (ngroup == 0) {
106 		return (0);	/* One thing fewer to worry backends */
107 	}
108 
109 	ia.groups.argc			= ngroup;
110 	ia.groups.argv			= pgroup;
111 	ia.arg[NSS_NETGR_MACHINE].argc	= nhost;
112 	ia.arg[NSS_NETGR_MACHINE].argv	= phost;
113 	ia.arg[NSS_NETGR_USER].argc	= nuser;
114 	ia.arg[NSS_NETGR_USER].argv	= puser;
115 	ia.arg[NSS_NETGR_DOMAIN].argc	= ndomain;
116 	ia.arg[NSS_NETGR_DOMAIN].argv	= pdomain;
117 	ia.status			= NSS_NETGR_NO;
118 
119 	(void) nss_search(&db_root, _nss_initf_netgroup,
120 	    NSS_DBOP_NETGROUP_IN, &ia);
121 	return (ia.status == NSS_NETGR_FOUND);
122 }
123 
124 int
125 innetgr(group, host, user, domain)
126 	const char *group, *host, *user, *domain;
127 {
128 #define	IA(charp)	\
129 	(nss_innetgr_argc)((charp) != 0), (nss_innetgr_argv)(&(charp))
130 
131 	return (__multi_innetgr(IA(group), IA(host), IA(user), IA(domain)));
132 }
133 
134 /*
135  * Context for setnetgrent()/getnetgrent().  If the user is being sensible
136  * the requests will be serialized anyway, but let's play safe and
137  * serialize them ourselves (anything to prevent a coredump)...
138  * We can't use lmutex_lock() here because we don't know what the backends
139  * that we call may call in turn.  They might call malloc()/free().
140  * So we use the brute-force atfork_lock_enter() instead.
141  */
142 static nss_backend_t	*getnetgrent_backend;
143 
144 int
145 setnetgrent(const char *netgroup)
146 {
147 	nss_backend_t	*be;
148 
149 	if (netgroup == NULL) {
150 		/* Prevent coredump, otherwise don't do anything profound */
151 		netgroup = "";
152 	}
153 
154 	atfork_lock_enter();
155 	be = getnetgrent_backend;
156 	if (be != NULL && NSS_INVOKE_DBOP(be, NSS_DBOP_SETENT,
157 	    (void *)netgroup) != NSS_SUCCESS) {
158 		(void) NSS_INVOKE_DBOP(be, NSS_DBOP_DESTRUCTOR, 0);
159 		be = NULL;
160 	}
161 	if (be == NULL) {
162 		struct nss_setnetgrent_args	args;
163 
164 		args.netgroup	= netgroup;
165 		args.iterator	= 0;
166 		(void) nss_search(&db_root, _nss_initf_netgroup,
167 		    NSS_DBOP_NETGROUP_SET, &args);
168 		be = args.iterator;
169 	}
170 	getnetgrent_backend = be;
171 	atfork_lock_exit();
172 	return (0);
173 }
174 
175 int
176 getnetgrent_r(machinep, namep, domainp, buffer, buflen)
177 	char		**machinep;
178 	char		**namep;
179 	char		**domainp;
180 	char		*buffer;
181 	int		buflen;
182 {
183 	struct nss_getnetgrent_args	args;
184 
185 	args.buffer	= buffer;
186 	args.buflen	= buflen;
187 	args.status	= NSS_NETGR_NO;
188 
189 	atfork_lock_enter();
190 	if (getnetgrent_backend != 0) {
191 		(void) NSS_INVOKE_DBOP(getnetgrent_backend,
192 			NSS_DBOP_GETENT, &args);
193 	}
194 	atfork_lock_exit();
195 
196 	if (args.status == NSS_NETGR_FOUND) {
197 		*machinep = args.retp[NSS_NETGR_MACHINE];
198 		*namep	  = args.retp[NSS_NETGR_USER];
199 		*domainp  = args.retp[NSS_NETGR_DOMAIN];
200 		return (1);
201 	} else {
202 		return (0);
203 	}
204 }
205 
206 static nss_XbyY_buf_t *buf;
207 
208 int
209 getnetgrent(machinep, namep, domainp)
210 	char		**machinep;
211 	char		**namep;
212 	char		**domainp;
213 {
214 	(void) NSS_XbyY_ALLOC(&buf, 0, NSS_BUFLEN_NETGROUP);
215 	return (getnetgrent_r(machinep, namep, domainp,
216 	    buf->buffer, buf->buflen));
217 }
218 
219 int
220 endnetgrent()
221 {
222 	atfork_lock_enter();
223 	if (getnetgrent_backend != 0) {
224 		(void) NSS_INVOKE_DBOP(getnetgrent_backend,
225 		    NSS_DBOP_DESTRUCTOR, 0);
226 		getnetgrent_backend = 0;
227 	}
228 	atfork_lock_exit();
229 	nss_delete(&db_root);	/* === ? */
230 	NSS_XbyY_FREE(&buf);
231 	return (0);
232 }
233