xref: /freebsd/lib/libc/rpc/getnetpath.c (revision ae83180158c4c937f170e31eff311b18c0286a93)
1 /*	$NetBSD: getnetpath.c,v 1.3 2000/07/06 03:10:34 christos 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 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 /*
41  * Copyright (c) 1989 by Sun Microsystems, Inc.
42  */
43 
44 #include "namespace.h"
45 #include <sys/cdefs.h>
46 #include <stdio.h>
47 #include <errno.h>
48 #include <netconfig.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <syslog.h>
52 #include "un-namespace.h"
53 
54 /*
55  * internal structure to keep track of a netpath "session"
56  */
57 struct netpath_chain {
58     struct netconfig *ncp;  /* an nconf entry */
59     struct netpath_chain *nchain_next;	/* next nconf entry allocated */
60 };
61 
62 
63 struct netpath_vars {
64     int   valid;	    /* token that indicates a valid netpath_vars */
65     void *nc_handlep;	    /* handle for current netconfig "session" */
66     char *netpath;	    /* pointer to current view-point in NETPATH */
67     char *netpath_start;    /* pointer to start of our copy of NETPATH */
68     struct netpath_chain *ncp_list;  /* list of nconfs allocated this session*/
69 };
70 
71 #define NP_VALID	0xf00d
72 #define NP_INVALID	0
73 
74 char *_get_next_token(char *, int);
75 
76 
77 /*
78  * A call to setnetpath() establishes a NETPATH "session".  setnetpath()
79  * must be called before the first call to getnetpath().  A "handle" is
80  * returned to distinguish the session; this handle should be passed
81  * subsequently to getnetpath().  (Handles are used to allow for nested calls
82  * to setnetpath()).
83  * If setnetpath() is unable to establish a session (due to lack of memory
84  * resources, or the absence of the /etc/netconfig file), a NULL pointer is
85  * returned.
86  */
87 
88 void *
89 setnetpath()
90 {
91 
92     struct netpath_vars *np_sessionp;   /* this session's variables */
93     char *npp;				/* NETPATH env variable */
94 
95 #ifdef MEM_CHK
96     malloc_debug(1);
97 #endif
98 
99     if ((np_sessionp =
100 	(struct netpath_vars *)malloc(sizeof (struct netpath_vars))) == NULL) {
101 	return (NULL);
102     }
103     if ((np_sessionp->nc_handlep = setnetconfig()) == NULL) {
104 	syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
105 	return (NULL);
106     }
107     np_sessionp->valid = NP_VALID;
108     np_sessionp->ncp_list = NULL;
109     if ((npp = getenv(NETPATH)) == NULL) {
110 	np_sessionp->netpath = NULL;
111     } else {
112 	(void) endnetconfig(np_sessionp->nc_handlep);/* won't need nc session*/
113 	np_sessionp->nc_handlep = NULL;
114 	if ((np_sessionp->netpath = malloc(strlen(npp)+1)) == NULL) {
115 	    free(np_sessionp);
116 	    return (NULL);
117 	} else {
118 	    (void) strcpy(np_sessionp->netpath, npp);
119 	}
120     }
121     np_sessionp->netpath_start = np_sessionp->netpath;
122     return ((void *)np_sessionp);
123 }
124 
125 /*
126  * When first called, getnetpath() returns a pointer to the netconfig
127  * database entry corresponding to the first valid NETPATH component.  The
128  * netconfig entry is formatted as a struct netconfig.
129  * On each subsequent call, getnetpath returns a pointer to the netconfig
130  * entry that corresponds to the next valid NETPATH component.  getnetpath
131  * can thus be used to search the netconfig database for all networks
132  * included in the NETPATH variable.
133  * When NETPATH has been exhausted, getnetpath() returns NULL.  It returns
134  * NULL and sets errno in case of an error (e.g., setnetpath was not called
135  * previously).
136  * getnetpath() silently ignores invalid NETPATH components.  A NETPATH
137  * compnent is invalid if there is no corresponding entry in the netconfig
138  * database.
139  * If the NETPATH variable is unset, getnetpath() behaves as if NETPATH
140  * were set to the sequence of default or visible networks in the netconfig
141  * database, in the order in which they are listed.
142  */
143 
144 struct netconfig *
145 getnetpath(handlep)
146     void *handlep;
147 {
148     struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
149     struct netconfig *ncp = NULL;   /* temp. holds a netconfig session */
150     struct netpath_chain *chainp;   /* holds chain of ncp's we alloc */
151     char  *npp;		/* holds current NETPATH */
152 
153     if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
154 	errno = EINVAL;
155 	return (NULL);
156     }
157     if (np_sessionp->netpath_start == NULL) {	/* NETPATH was not set */
158 	do {                /* select next visible network */
159 	    if (np_sessionp->nc_handlep == NULL) {
160 		np_sessionp->nc_handlep = setnetconfig();
161 		if (np_sessionp->nc_handlep == NULL)
162 		    syslog (LOG_ERR, "rpc: failed to open " NETCONFIG);
163 	    }
164 	    if ((ncp = getnetconfig(np_sessionp->nc_handlep)) == NULL) {
165 		return(NULL);
166 	    }
167 	} while ((ncp->nc_flag & NC_VISIBLE) == 0);
168 	return (ncp);
169     }
170     /*
171      * Find first valid network ID in netpath.
172      */
173     while ((npp = np_sessionp->netpath) != NULL && strlen(npp) != 0) {
174 	np_sessionp->netpath = _get_next_token(npp, ':');
175     	/*
176     	 * npp is a network identifier.
177 	 */
178 	if ((ncp = getnetconfigent(npp)) != NULL) {
179 	    chainp = (struct netpath_chain *)	/* cobble alloc chain entry */
180 		    malloc(sizeof (struct netpath_chain));
181 	    chainp->ncp = ncp;
182 	    chainp->nchain_next = NULL;
183 	    if (np_sessionp->ncp_list == NULL) {
184 		np_sessionp->ncp_list = chainp;
185 	    } else {
186 		np_sessionp->ncp_list->nchain_next = chainp;
187 	    }
188 	    return (ncp);
189 	}
190 	/* couldn't find this token in the database; go to next one. */
191     }
192     return (NULL);
193 }
194 
195 /*
196  * endnetpath() may be called to unbind NETPATH when processing is complete,
197  * releasing resources for reuse.  It returns 0 on success and -1 on failure
198  * (e.g. if setnetpath() was not called previously.
199  */
200 int
201 endnetpath(handlep)
202     void *handlep;
203 {
204     struct netpath_vars *np_sessionp = (struct netpath_vars *)handlep;
205     struct netpath_chain *chainp, *lastp;
206 
207     if (np_sessionp == NULL || np_sessionp->valid != NP_VALID) {
208 	errno = EINVAL;
209 	return (-1);
210     }
211     if (np_sessionp->nc_handlep != NULL)
212 	endnetconfig(np_sessionp->nc_handlep);
213     if (np_sessionp->netpath_start != NULL)
214 	free(np_sessionp->netpath_start);
215     for (chainp = np_sessionp->ncp_list; chainp != NULL;
216 	    lastp=chainp, chainp=chainp->nchain_next, free(lastp)) {
217 	freenetconfigent(chainp->ncp);
218     }
219     free(np_sessionp);
220 #ifdef MEM_CHK
221     if (malloc_verify() == 0) {
222 	fprintf(stderr, "memory heap corrupted in endnetpath\n");
223 	exit(1);
224     }
225 #endif
226     return (0);
227 }
228 
229 
230 
231 /*
232  * Returns pointer to the rest-of-the-string after the current token.
233  * The token itself starts at arg, and we null terminate it.  We return NULL
234  * if either the arg is empty, or if this is the last token.
235  */
236 
237 char *
238 _get_next_token(npp, token)
239 char *npp;		/* string */
240 int token;		/* char to parse string for */
241 {
242     char  *cp;		/* char pointer */
243     char  *np;		/* netpath pointer */
244     char  *ep;		/* escape pointer */
245 
246     if ((cp = strchr(npp, token)) == NULL) {
247 	return (NULL);
248     }
249     /*
250      * did find a token, but it might be escaped.
251      */
252     if (cp[-1] == '\\') {
253         /* if slash was also escaped, carry on, otherwise find next token */
254         if (cp[-2] != '\\') {
255 	    /* shift r-o-s  onto the escaped token */
256 	    strcpy(&cp[-1], cp);    /* XXX: overlapping string copy */
257 	    /*
258 	     * Do a recursive call.
259 	     * We don't know how many escaped tokens there might be.
260 	     */
261 	    return (_get_next_token(cp, token));
262 	}
263     }
264 
265     *cp++ = '\0';		/* null-terminate token */
266     /* get rid of any backslash escapes */
267     ep = npp;
268     while ((np = strchr(ep, '\\')) != 0) {
269 	if (np[1] == '\\')
270 	    np++;
271 	strcpy(np, (ep = &np[1]));  /* XXX: overlapping string copy */
272     }
273     return (cp);		/* return ptr to r-o-s */
274 }
275