xref: /netbsd/lib/libc/rpc/getnetpath.c (revision bf9ec67e)
1 /*	$NetBSD: getnetpath.c,v 1.6 2002/04/16 19:19:33 groo Exp $	*/
2 
3 /*
4  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
5  * unrestricted use provided that this legend is included on all tape
6  * media and as a part of the software program in whole or part.  Users
7  * may copy or modify Sun RPC without charge, but are not authorized
8  * to license or distribute it to anyone else except as part of a product or
9  * program developed by the user or with the express written consent of
10  * Sun Microsystems, Inc.
11  *
12  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
13  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
14  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
15  *
16  * Sun RPC is provided with no support and without any obligation on the
17  * part of Sun Microsystems, Inc. to assist in its use, correction,
18  * modification or enhancement.
19  *
20  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
21  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
22  * OR ANY PART THEREOF.
23  *
24  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
25  * or profits or other special, indirect and consequential damages, even if
26  * Sun has been advised of the possibility of such damages.
27  *
28  * Sun Microsystems, Inc.
29  * 2550 Garcia Avenue
30  * Mountain View, California  94043
31  */
32 /*
33 #ifndef lint
34 static        char sccsid[] = "@(#)getnetpath.c	1.11 91/12/19 SMI";
35 #endif
36 */
37 
38 /*
39  * Copyright (c) 1989 by Sun Microsystems, Inc.
40  */
41 
42 #include "namespace.h"
43 #include <sys/cdefs.h>
44 #include <stdio.h>
45 #include <assert.h>
46 #include <errno.h>
47 #include <netconfig.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <syslog.h>
51 
52 #ifdef __weak_alias
53 __weak_alias(getnetpath,_getnetpath)
54 __weak_alias(setnetpath,_setnetpath)
55 #endif
56 
57 /*
58  * internal structure to keep track of a netpath "session"
59  */
60 struct netpath_chain {
61 	struct netconfig *ncp;  		/* an nconf entry */
62 	struct netpath_chain *nchain_next;	/* next nconf entry allocated */
63 };
64 
65 
66 struct netpath_vars {
67 	int   valid;		/* token that indicates a valid netpath_vars */
68 	void *nc_handlep;	/* handle for current netconfig "session" */
69 	char *netpath;		/* pointer to current view-point in NETPATH */
70 	char *netpath_start;	/* pointer to start of our copy of NETPATH */
71 	struct netpath_chain *ncp_list;  /* list of nconfs allocated this session*/
72 };
73 
74 #define NP_VALID	0xf00d
75 #define NP_INVALID	0
76 
77 char *_get_next_token __P((char *, int));
78 
79 
80 /*
81  * A call to setnetpath() establishes a NETPATH "session".  setnetpath()
82  * must be called before the first call to getnetpath().  A "handle" is
83  * returned to distinguish the session; this handle should be passed
84  * subsequently to getnetpath().  (Handles are used to allow for nested calls
85  * to setnetpath()).
86  * If setnetpath() is unable to establish a session (due to lack of memory
87  * resources, or the absence of the /etc/netconfig file), a NULL pointer is
88  * returned.
89  */
90 
91 void *
92 setnetpath()
93 {
94 	struct netpath_vars *np_sessionp;   /* this session's variables */
95 	char *npp;				/* NETPATH env variable */
96 
97 #ifdef MEM_CHK
98 	malloc_debug(1);
99 #endif
100 
101 	if ((np_sessionp = (struct netpath_vars *)
102 	    malloc(sizeof (struct netpath_vars))) == NULL)
103 		return (NULL);
104 	if ((np_sessionp->nc_handlep = setnetconfig()) == NULL) {
105 		syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
106 		return (NULL);
107 	}
108 	np_sessionp->valid = NP_VALID;
109 	np_sessionp->ncp_list = NULL;
110 	if ((npp = getenv(NETPATH)) == NULL)
111 		np_sessionp->netpath = NULL;
112 	else {
113 		(void) endnetconfig(np_sessionp->nc_handlep);
114 					/* won't need nc session*/
115 		np_sessionp->nc_handlep = NULL;
116 		if ((np_sessionp->netpath = malloc(strlen(npp)+1)) == NULL) {
117 			free(np_sessionp);
118 			return (NULL);
119 		} else
120 			(void) strcpy(np_sessionp->netpath, npp);
121 	}
122 	np_sessionp->netpath_start = np_sessionp->netpath;
123 	return ((void *)np_sessionp);
124 }
125 
126 /*
127  * When first called, getnetpath() returns a pointer to the netconfig
128  * database entry corresponding to the first valid NETPATH component.  The
129  * netconfig entry is formatted as a struct netconfig.
130  * On each subsequent call, getnetpath returns a pointer to the netconfig
131  * entry that corresponds to the next valid NETPATH component.  getnetpath
132  * can thus be used to search the netconfig database for all networks
133  * included in the NETPATH variable.
134  * When NETPATH has been exhausted, getnetpath() returns NULL.  It returns
135  * NULL and sets errno in case of an error (e.g., setnetpath was not called
136  * previously).
137  * getnetpath() silently ignores invalid NETPATH components.  A NETPATH
138  * compnent is invalid if there is no corresponding entry in the netconfig
139  * database.
140  * If the NETPATH variable is unset, getnetpath() behaves as if NETPATH
141  * were set to the sequence of default or visible networks in the netconfig
142  * database, in the order in which they are listed.
143  */
144 
145 struct netconfig *
146 getnetpath(handlep)
147 	void *handlep;
148 {
149 	struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
150 	struct netconfig *ncp = NULL;   /* temp. holds a netconfig session */
151 	struct netpath_chain *chainp;   /* holds chain of ncp's we alloc */
152 	char  *npp;		/* holds current NETPATH */
153 
154 	if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
155 		errno = EINVAL;
156 		return (NULL);
157 	}
158 	if (np_sessionp->netpath_start == NULL) { /* NETPATH was not set */
159 		do {                /* select next visible network */
160 			if (np_sessionp->nc_handlep == NULL) {
161 				np_sessionp->nc_handlep = setnetconfig();
162 				if (np_sessionp->nc_handlep == NULL)
163 					syslog (LOG_ERR,
164 					    "rpc: failed to open " NETCONFIG);
165 			}
166 			if ((ncp = getnetconfig(np_sessionp->nc_handlep))
167 			    == NULL)
168 				return(NULL);
169 		} while ((ncp->nc_flag & NC_VISIBLE) == 0);
170 		return (ncp);
171 	}
172 	/*
173 	 * Find first valid network ID in netpath.
174 	 */
175 	while ((npp = np_sessionp->netpath) != NULL && strlen(npp) != 0) {
176 		np_sessionp->netpath = _get_next_token(npp, ':');
177 		/*
178 		 * npp is a network identifier.
179 		 */
180 		if ((ncp = getnetconfigent(npp)) != NULL) {
181 					/* cobble alloc chain entry */
182 			chainp = (struct netpath_chain *)
183 			    malloc(sizeof (struct netpath_chain));
184 			chainp->ncp = ncp;
185 			chainp->nchain_next = NULL;
186 			if (np_sessionp->ncp_list == NULL)
187 				np_sessionp->ncp_list = chainp;
188 			else
189 				np_sessionp->ncp_list->nchain_next = chainp;
190 			return (ncp);
191 		}
192 		/* couldn't find this token in the database; go to next one. */
193 	}
194 	return (NULL);
195 }
196 
197 /*
198  * endnetpath() may be called to unbind NETPATH when processing is complete,
199  * releasing resources for reuse.  It returns 0 on success and -1 on failure
200  * (e.g. if setnetpath() was not called previously.
201  */
202 int
203 endnetpath(handlep)
204 	void *handlep;
205 {
206 	struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
207 	struct netpath_chain *chainp, *lastp;
208 
209 	if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
210 		errno = EINVAL;
211 		return (-1);
212 	}
213 	if (np_sessionp->nc_handlep != NULL)
214 		endnetconfig(np_sessionp->nc_handlep);
215 	if (np_sessionp->netpath_start != NULL)
216 		free(np_sessionp->netpath_start);
217 	for (chainp = np_sessionp->ncp_list; chainp != NULL;
218 	    lastp=chainp, chainp=chainp->nchain_next, free(lastp)) {
219 		freenetconfigent(chainp->ncp);
220 	}
221 	free(np_sessionp);
222 #ifdef MEM_CHK
223 	if (malloc_verify() == 0) {
224 		fprintf(stderr, "memory heap corrupted in endnetpath\n");
225 		exit(1);
226 	}
227 #endif
228 	return (0);
229 }
230 
231 
232 /*
233  * Returns pointer to the rest-of-the-string after the current token.
234  * The token itself starts at arg, and we null terminate it.  We return NULL
235  * if either the arg is empty, or if this is the last token.
236  */
237 
238 char *
239 _get_next_token(npp, token)
240 	char *npp;		/* string */
241 	int token;		/* char to parse string for */
242 {
243 	char  *cp;		/* char pointer */
244 	char  *np;		/* netpath pointer */
245 	char  *ep;		/* escape pointer */
246 
247 	_DIAGASSERT(npp != NULL);
248 	_DIAGASSERT(token != NULL);
249 
250 	if ((cp = strchr(npp, token)) == NULL)
251 		return (NULL);
252 	/*
253 	 * did find a token, but it might be escaped.
254 	 */
255 	if ((cp > npp) && (cp[-1] == '\\')) {
256 		/*
257 		 * if slash was also escaped, carry on, otherwise find
258 		 * next token
259 		 */
260 		if ((cp > npp + 1) && (cp[-2] != '\\')) {
261 			/* shift r-o-s  onto the escaped token */
262 			strcpy(&cp[-1], cp);  /* XXX: overlapping string copy */
263 			/*
264 			 * Do a recursive call.
265 			 * We don't know how many escaped tokens there might be.
266 			 */
267 			return (_get_next_token(cp, token));
268 		}
269 	}
270 
271 	*cp++ = '\0';		/* null-terminate token */
272 	/* get rid of any backslash escapes */
273 	ep = npp;
274 	while ((np = strchr(ep, '\\')) != 0) {
275 		if (np[1] == '\\')
276 			np++;
277 		strcpy(np, (ep = &np[1]));  /* XXX: overlapping string copy */
278 	}
279 	return (cp);		/* return ptr to r-o-s */
280 }
281