xref: /freebsd/lib/libc/rpc/getnetconfig.c (revision 7431dfd4580e850375fe5478d92ec770344db098)
1 /*	$NetBSD: getnetconfig.c,v 1.3 2000/07/06 03:10:34 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 2009, Sun Microsystems, Inc.
5  * 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 are met:
9  * - Redistributions of source code must retain the above copyright notice,
10  *   this list of conditions and the following disclaimer.
11  * - Redistributions in binary form must reproduce the above copyright notice,
12  *   this list of conditions and the following disclaimer in the documentation
13  *   and/or other materials provided with the distribution.
14  * - Neither the name of Sun Microsystems, Inc. nor the names of its
15  *   contributors may be used to endorse or promote products derived
16  *   from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #if defined(LIBC_SCCS) && !defined(lint)
32 static char sccsid[] = "@(#)getnetconfig.c	1.12 91/12/19 SMI";
33 #endif
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 /*
38  * Copyright (c) 1989 by Sun Microsystems, Inc.
39  */
40 
41 #include "namespace.h"
42 #include "reentrant.h"
43 #include <stdio.h>
44 #include <errno.h>
45 #include <netconfig.h>
46 #include <stddef.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <rpc/rpc.h>
50 #include <unistd.h>
51 #include "un-namespace.h"
52 #include "rpc_com.h"
53 
54 /*
55  * The five library routines in this file provide application access to the
56  * system network configuration database, /etc/netconfig.  In addition to the
57  * netconfig database and the routines for accessing it, the environment
58  * variable NETPATH and its corresponding routines in getnetpath.c may also be
59  * used to specify the network transport to be used.
60  */
61 
62 
63 /*
64  * netconfig errors
65  */
66 
67 #define NC_NONETCONFIG	ENOENT
68 #define NC_NOMEM	ENOMEM
69 #define NC_NOTINIT	EINVAL	    /* setnetconfig was not called first */
70 #define NC_BADFILE	EBADF	    /* format for netconfig file is bad */
71 #define NC_NOTFOUND	ENOPROTOOPT /* specified netid was not found */
72 
73 /*
74  * semantics as strings (should be in netconfig.h)
75  */
76 #define NC_TPI_CLTS_S	    "tpi_clts"
77 #define	NC_TPI_COTS_S	    "tpi_cots"
78 #define	NC_TPI_COTS_ORD_S   "tpi_cots_ord"
79 #define	NC_TPI_RAW_S        "tpi_raw"
80 
81 /*
82  * flags as characters (also should be in netconfig.h)
83  */
84 #define	NC_NOFLAG_C	'-'
85 #define	NC_VISIBLE_C	'v'
86 #define	NC_BROADCAST_C	'b'
87 
88 /*
89  * Character used to indicate there is no name-to-address lookup library
90  */
91 #define NC_NOLOOKUP	"-"
92 
93 static const char * const _nc_errors[] = {
94     "Netconfig database not found",
95     "Not enough memory",
96     "Not initialized",
97     "Netconfig database has invalid format",
98     "Netid not found in netconfig database"
99 };
100 
101 struct netconfig_info {
102     int		eof;	/* all entries has been read */
103     int		ref;	/* # of times setnetconfig() has been called */
104     struct netconfig_list	*head;	/* head of the list */
105     struct netconfig_list	*tail;	/* last of the list */
106 };
107 
108 struct netconfig_list {
109     char			*linep;	/* hold line read from netconfig */
110     struct netconfig		*ncp;
111     struct netconfig_list	*next;
112 };
113 
114 struct netconfig_vars {
115     int   valid;	/* token that indicates a valid netconfig_vars */
116     int   flag;		/* first time flag */
117     struct netconfig_list *nc_configs;  /* pointer to the current netconfig entry */
118 };
119 
120 #define NC_VALID	0xfeed
121 #define NC_STORAGE	0xf00d
122 #define NC_INVALID	0
123 
124 
125 static int *__nc_error(void);
126 static int parse_ncp(char *, struct netconfig *);
127 static struct netconfig *dup_ncp(struct netconfig *);
128 
129 
130 static FILE *nc_file;		/* for netconfig db */
131 static mutex_t nc_file_lock = MUTEX_INITIALIZER;
132 
133 static struct netconfig_info	ni = { 0, 0, NULL, NULL};
134 static mutex_t ni_lock = MUTEX_INITIALIZER;
135 
136 static thread_key_t nc_key;
137 static once_t nc_once = ONCE_INITIALIZER;
138 static int nc_key_error;
139 
140 static void
141 nc_key_init(void)
142 {
143 
144 	nc_key_error = thr_keycreate(&nc_key, free);
145 }
146 
147 #define MAXNETCONFIGLINE    1000
148 
149 static int *
150 __nc_error()
151 {
152 	static int nc_error = 0;
153 	int *nc_addr;
154 
155 	/*
156 	 * Use the static `nc_error' if we are the main thread
157 	 * (including non-threaded programs), or if an allocation
158 	 * fails.
159 	 */
160 	if (thr_main())
161 		return (&nc_error);
162 	if (thr_once(&nc_once, nc_key_init) != 0 || nc_key_error != 0)
163 		return (&nc_error);
164 	if ((nc_addr = (int *)thr_getspecific(nc_key)) == NULL) {
165 		nc_addr = (int *)malloc(sizeof (int));
166 		if (thr_setspecific(nc_key, (void *) nc_addr) != 0) {
167 			if (nc_addr)
168 				free(nc_addr);
169 			return (&nc_error);
170 		}
171 		*nc_addr = 0;
172 	}
173 	return (nc_addr);
174 }
175 
176 #define nc_error        (*(__nc_error()))
177 /*
178  * A call to setnetconfig() establishes a /etc/netconfig "session".  A session
179  * "handle" is returned on a successful call.  At the start of a session (after
180  * a call to setnetconfig()) searches through the /etc/netconfig database will
181  * proceed from the start of the file.  The session handle must be passed to
182  * getnetconfig() to parse the file.  Each call to getnetconfig() using the
183  * current handle will process one subsequent entry in /etc/netconfig.
184  * setnetconfig() must be called before the first call to getnetconfig().
185  * (Handles are used to allow for nested calls to setnetpath()).
186  *
187  * A new session is established with each call to setnetconfig(), with a new
188  * handle being returned on each call.  Previously established sessions remain
189  * active until endnetconfig() is called with that session's handle as an
190  * argument.
191  *
192  * setnetconfig() need *not* be called before a call to getnetconfigent().
193  * setnetconfig() returns a NULL pointer on failure (for example, if
194  * the netconfig database is not present).
195  */
196 void *
197 setnetconfig()
198 {
199     struct netconfig_vars *nc_vars;
200 
201     if ((nc_vars = (struct netconfig_vars *)malloc(sizeof
202 		(struct netconfig_vars))) == NULL) {
203 	return(NULL);
204     }
205 
206     /*
207      * For multiple calls, i.e. nc_file is not NULL, we just return the
208      * handle without reopening the netconfig db.
209      */
210     mutex_lock(&ni_lock);
211     ni.ref++;
212     mutex_unlock(&ni_lock);
213 
214     mutex_lock(&nc_file_lock);
215     if ((nc_file != NULL) || (nc_file = fopen(NETCONFIG, "r")) != NULL) {
216 	nc_vars->valid = NC_VALID;
217 	nc_vars->flag = 0;
218 	nc_vars->nc_configs = ni.head;
219 	mutex_unlock(&nc_file_lock);
220 	return ((void *)nc_vars);
221     }
222     mutex_unlock(&nc_file_lock);
223 
224     mutex_lock(&ni_lock);
225     ni.ref--;
226     mutex_unlock(&ni_lock);
227 
228     nc_error = NC_NONETCONFIG;
229     free(nc_vars);
230     return (NULL);
231 }
232 
233 
234 /*
235  * When first called, getnetconfig() returns a pointer to the first entry in
236  * the netconfig database, formatted as a struct netconfig.  On each subsequent
237  * call, getnetconfig() returns a pointer to the next entry in the database.
238  * getnetconfig() can thus be used to search the entire netconfig file.
239  * getnetconfig() returns NULL at end of file.
240  */
241 
242 struct netconfig *
243 getnetconfig(handlep)
244 void *handlep;
245 {
246     struct netconfig_vars *ncp = (struct netconfig_vars *)handlep;
247     char *stringp;		/* tmp string pointer */
248     struct netconfig_list	*list;
249     struct netconfig *np;
250     struct netconfig *result;
251 
252     /*
253      * Verify that handle is valid
254      */
255     mutex_lock(&nc_file_lock);
256     if (ncp == NULL || nc_file == NULL) {
257 	nc_error = NC_NOTINIT;
258 	mutex_unlock(&nc_file_lock);
259 	return (NULL);
260     }
261     mutex_unlock(&nc_file_lock);
262 
263     switch (ncp->valid) {
264     case NC_VALID:
265 	/*
266 	 * If entry has already been read into the list,
267 	 * we return the entry in the linked list.
268 	 * If this is the first time call, check if there are any entries in
269 	 * linked list.  If no entries, we need to read the netconfig db.
270 	 * If we have been here and the next entry is there, we just return
271 	 * it.
272 	 */
273 	if (ncp->flag == 0) {	/* first time */
274 	    ncp->flag = 1;
275 	    mutex_lock(&ni_lock);
276 	    ncp->nc_configs = ni.head;
277 	    mutex_unlock(&ni_lock);
278 	    if (ncp->nc_configs != NULL)	/* entry already exist */
279 		return(ncp->nc_configs->ncp);
280 	}
281 	else if (ncp->nc_configs != NULL && ncp->nc_configs->next != NULL) {
282 	    ncp->nc_configs = ncp->nc_configs->next;
283 	    return(ncp->nc_configs->ncp);
284 	}
285 
286 	/*
287 	 * If we cannot find the entry in the list and is end of file,
288 	 * we give up.
289 	 */
290 	mutex_lock(&ni_lock);
291 	if (ni.eof == 1) {
292 		mutex_unlock(&ni_lock);
293 		return(NULL);
294 	}
295 	mutex_unlock(&ni_lock);
296 
297 	break;
298     default:
299 	nc_error = NC_NOTINIT;
300 	return (NULL);
301     }
302 
303     stringp = (char *) malloc(MAXNETCONFIGLINE);
304     if (stringp == NULL)
305     	return (NULL);
306 
307 #ifdef MEM_CHK
308     if (malloc_verify() == 0) {
309 	fprintf(stderr, "memory heap corrupted in getnetconfig\n");
310 	exit(1);
311     }
312 #endif
313 
314     /*
315      * Read a line from netconfig file.
316      */
317     mutex_lock(&nc_file_lock);
318     do {
319 	if (fgets(stringp, MAXNETCONFIGLINE, nc_file) == NULL) {
320 	    free(stringp);
321 	    mutex_lock(&ni_lock);
322 	    ni.eof = 1;
323 	    mutex_unlock(&ni_lock);
324 	    mutex_unlock(&nc_file_lock);
325 	    return (NULL);
326         }
327     } while (*stringp == '#');
328     mutex_unlock(&nc_file_lock);
329 
330     list = (struct netconfig_list *) malloc(sizeof (struct netconfig_list));
331     if (list == NULL) {
332     	free(stringp);
333     	return(NULL);
334     }
335     np = (struct netconfig *) malloc(sizeof (struct netconfig));
336     if (np == NULL) {
337     	free(stringp);
338 	free(list);
339     	return(NULL);
340     }
341     list->ncp = np;
342     list->next = NULL;
343     list->ncp->nc_lookups = NULL;
344     list->linep = stringp;
345     if (parse_ncp(stringp, list->ncp) == -1) {
346 	free(stringp);
347 	free(np);
348 	free(list);
349 	return (NULL);
350     }
351     else {
352 	/*
353 	 * If this is the first entry that's been read, it is the head of
354 	 * the list.  If not, put the entry at the end of the list.
355 	 * Reposition the current pointer of the handle to the last entry
356 	 * in the list.
357 	 */
358 	mutex_lock(&ni_lock);
359 	if (ni.head == NULL) {	/* first entry */
360 	    ni.head = ni.tail = list;
361 	}
362     	else {
363     	    ni.tail->next = list;
364     	    ni.tail = ni.tail->next;
365     	}
366 	ncp->nc_configs = ni.tail;
367 	result = ni.tail->ncp;
368 	mutex_unlock(&ni_lock);
369 	return(result);
370     }
371 }
372 
373 /*
374  * endnetconfig() may be called to "unbind" or "close" the netconfig database
375  * when processing is complete, releasing resources for reuse.  endnetconfig()
376  * may not be called before setnetconfig().  endnetconfig() returns 0 on
377  * success and -1 on failure (for example, if setnetconfig() was not called
378  * previously).
379  */
380 int
381 endnetconfig(handlep)
382 void *handlep;
383 {
384     struct netconfig_vars *nc_handlep = (struct netconfig_vars *)handlep;
385 
386     struct netconfig_list *q, *p;
387 
388     /*
389      * Verify that handle is valid
390      */
391     if (nc_handlep == NULL || (nc_handlep->valid != NC_VALID &&
392 	    nc_handlep->valid != NC_STORAGE)) {
393 	nc_error = NC_NOTINIT;
394 	return (-1);
395     }
396 
397     /*
398      * Return 0 if anyone still needs it.
399      */
400     nc_handlep->valid = NC_INVALID;
401     nc_handlep->flag = 0;
402     nc_handlep->nc_configs = NULL;
403     mutex_lock(&ni_lock);
404     if (--ni.ref > 0) {
405 	mutex_unlock(&ni_lock);
406     	free(nc_handlep);
407 	return(0);
408     }
409 
410     /*
411      * Noone needs these entries anymore, then frees them.
412      * Make sure all info in netconfig_info structure has been reinitialized.
413      */
414     q = ni.head;
415     ni.eof = ni.ref = 0;
416     ni.head = NULL;
417     ni.tail = NULL;
418     mutex_unlock(&ni_lock);
419 
420     while (q != NULL) {
421 	p = q->next;
422 	if (q->ncp->nc_lookups != NULL) free(q->ncp->nc_lookups);
423 	free(q->ncp);
424 	free(q->linep);
425 	free(q);
426 	q = p;
427     }
428     free(nc_handlep);
429 
430     mutex_lock(&nc_file_lock);
431     fclose(nc_file);
432     nc_file = NULL;
433     mutex_unlock(&nc_file_lock);
434 
435     return (0);
436 }
437 
438 /*
439  * getnetconfigent(netid) returns a pointer to the struct netconfig structure
440  * corresponding to netid.  It returns NULL if netid is invalid (that is, does
441  * not name an entry in the netconfig database).  It returns NULL and sets
442  * errno in case of failure (for example, if the netconfig database cannot be
443  * opened).
444  */
445 
446 struct netconfig *
447 getnetconfigent(netid)
448 	const char *netid;
449 {
450     FILE *file;		/* NETCONFIG db's file pointer */
451     char *linep;	/* holds current netconfig line */
452     char *stringp;	/* temporary string pointer */
453     struct netconfig *ncp = NULL;   /* returned value */
454     struct netconfig_list *list;	/* pointer to cache list */
455 
456     nc_error = NC_NOTFOUND;	/* default error. */
457     if (netid == NULL || strlen(netid) == 0) {
458 	return (NULL);
459     }
460 
461     /*
462      * Look up table if the entries have already been read and parsed in
463      * getnetconfig(), then copy this entry into a buffer and return it.
464      * If we cannot find the entry in the current list and there are more
465      * entries in the netconfig db that has not been read, we then read the
466      * db and try find the match netid.
467      * If all the netconfig db has been read and placed into the list and
468      * there is no match for the netid, return NULL.
469      */
470     mutex_lock(&ni_lock);
471     if (ni.head != NULL) {
472 	for (list = ni.head; list; list = list->next) {
473 	    if (strcmp(list->ncp->nc_netid, netid) == 0) {
474 		mutex_unlock(&ni_lock);
475 	        return(dup_ncp(list->ncp));
476 	    }
477 	}
478 	if (ni.eof == 1) {	/* that's all the entries */
479 		mutex_unlock(&ni_lock);
480 		return(NULL);
481 	}
482     }
483     mutex_unlock(&ni_lock);
484 
485 
486     if ((file = fopen(NETCONFIG, "r")) == NULL) {
487 	nc_error = NC_NONETCONFIG;
488 	return (NULL);
489     }
490 
491     if ((linep = malloc(MAXNETCONFIGLINE)) == NULL) {
492 	fclose(file);
493 	nc_error = NC_NOMEM;
494 	return (NULL);
495     }
496     do {
497 	ptrdiff_t len;
498 	char *tmpp;	/* tmp string pointer */
499 
500 	do {
501 	    if ((stringp = fgets(linep, MAXNETCONFIGLINE, file)) == NULL) {
502 		break;
503 	    }
504 	} while (*stringp == '#');
505 	if (stringp == NULL) {	    /* eof */
506 	    break;
507 	}
508 	if ((tmpp = strpbrk(stringp, "\t ")) == NULL) {	/* can't parse file */
509 	    nc_error = NC_BADFILE;
510 	    break;
511 	}
512 	if (strlen(netid) == (size_t) (len = tmpp - stringp) &&	/* a match */
513 		strncmp(stringp, netid, (size_t)len) == 0) {
514 	    if ((ncp = (struct netconfig *)
515 		    malloc(sizeof (struct netconfig))) == NULL) {
516 		break;
517 	    }
518 	    ncp->nc_lookups = NULL;
519 	    if (parse_ncp(linep, ncp) == -1) {
520 		free(ncp);
521 		ncp = NULL;
522 	    }
523 	    break;
524 	}
525     } while (stringp != NULL);
526     if (ncp == NULL) {
527 	free(linep);
528     }
529     fclose(file);
530     return(ncp);
531 }
532 
533 /*
534  * freenetconfigent(netconfigp) frees the netconfig structure pointed to by
535  * netconfigp (previously returned by getnetconfigent()).
536  */
537 
538 void
539 freenetconfigent(netconfigp)
540 	struct netconfig *netconfigp;
541 {
542     if (netconfigp != NULL) {
543 	free(netconfigp->nc_netid);	/* holds all netconfigp's strings */
544 	if (netconfigp->nc_lookups != NULL)
545 	    free(netconfigp->nc_lookups);
546 	free(netconfigp);
547     }
548     return;
549 }
550 
551 /*
552  * Parse line and stuff it in a struct netconfig
553  * Typical line might look like:
554  *	udp tpi_cots vb inet udp /dev/udp /usr/lib/ip.so,/usr/local/ip.so
555  *
556  * We return -1 if any of the tokens don't parse, or malloc fails.
557  *
558  * Note that we modify stringp (putting NULLs after tokens) and
559  * we set the ncp's string field pointers to point to these tokens within
560  * stringp.
561  */
562 
563 static int
564 parse_ncp(stringp, ncp)
565 char *stringp;		/* string to parse */
566 struct netconfig *ncp;	/* where to put results */
567 {
568     char    *tokenp;	/* for processing tokens */
569     char    *lasts;
570     char    **nc_lookups;
571 
572     nc_error = NC_BADFILE;	/* nearly anything that breaks is for this reason */
573     stringp[strlen(stringp)-1] = '\0';	/* get rid of newline */
574     /* netid */
575     if ((ncp->nc_netid = strtok_r(stringp, "\t ", &lasts)) == NULL) {
576 	return (-1);
577     }
578 
579     /* semantics */
580     if ((tokenp = strtok_r(NULL, "\t ", &lasts)) == NULL) {
581 	return (-1);
582     }
583     if (strcmp(tokenp, NC_TPI_COTS_ORD_S) == 0)
584 	ncp->nc_semantics = NC_TPI_COTS_ORD;
585     else if (strcmp(tokenp, NC_TPI_COTS_S) == 0)
586 	ncp->nc_semantics = NC_TPI_COTS;
587     else if (strcmp(tokenp, NC_TPI_CLTS_S) == 0)
588 	ncp->nc_semantics = NC_TPI_CLTS;
589     else if (strcmp(tokenp, NC_TPI_RAW_S) == 0)
590 	ncp->nc_semantics = NC_TPI_RAW;
591     else
592 	return (-1);
593 
594     /* flags */
595     if ((tokenp = strtok_r(NULL, "\t ", &lasts)) == NULL) {
596 	return (-1);
597     }
598     for (ncp->nc_flag = NC_NOFLAG; *tokenp != '\0';
599 	    tokenp++) {
600 	switch (*tokenp) {
601 	case NC_NOFLAG_C:
602 	    break;
603 	case NC_VISIBLE_C:
604 	    ncp->nc_flag |= NC_VISIBLE;
605 	    break;
606 	case NC_BROADCAST_C:
607 	    ncp->nc_flag |= NC_BROADCAST;
608 	    break;
609 	default:
610 	    return (-1);
611 	}
612     }
613     /* protocol family */
614     if ((ncp->nc_protofmly = strtok_r(NULL, "\t ", &lasts)) == NULL) {
615 	return (-1);
616     }
617     /* protocol name */
618     if ((ncp->nc_proto = strtok_r(NULL, "\t ", &lasts)) == NULL) {
619 	return (-1);
620     }
621     /* network device */
622     if ((ncp->nc_device = strtok_r(NULL, "\t ", &lasts)) == NULL) {
623 	return (-1);
624     }
625     if ((tokenp = strtok_r(NULL, "\t ", &lasts)) == NULL) {
626 	return (-1);
627     }
628     if (strcmp(tokenp, NC_NOLOOKUP) == 0) {
629 	ncp->nc_nlookups = 0;
630 	ncp->nc_lookups = NULL;
631     } else {
632 	char *cp;	    /* tmp string */
633 
634 	if (ncp->nc_lookups != NULL)	/* from last visit */
635 	    free(ncp->nc_lookups);
636 	ncp->nc_lookups = NULL;
637 	ncp->nc_nlookups = 0;
638 	while ((cp = tokenp) != NULL) {
639 	    if ((nc_lookups = realloc(ncp->nc_lookups,
640 		(ncp->nc_nlookups + 1) * sizeof *ncp->nc_lookups)) == NULL) {
641 		    free(ncp->nc_lookups);
642 		    ncp->nc_lookups = NULL;
643 		    return (-1);
644 	    }
645 	    tokenp = _get_next_token(cp, ',');
646 	    ncp->nc_lookups = nc_lookups;
647 	    ncp->nc_lookups[ncp->nc_nlookups++] = cp;
648 	}
649     }
650     return (0);
651 }
652 
653 
654 /*
655  * Returns a string describing the reason for failure.
656  */
657 char *
658 nc_sperror()
659 {
660     const char *message;
661 
662     switch(nc_error) {
663     case NC_NONETCONFIG:
664 	message = _nc_errors[0];
665 	break;
666     case NC_NOMEM:
667 	message = _nc_errors[1];
668 	break;
669     case NC_NOTINIT:
670 	message = _nc_errors[2];
671 	break;
672     case NC_BADFILE:
673 	message = _nc_errors[3];
674 	break;
675     case NC_NOTFOUND:
676 	message = _nc_errors[4];
677 	break;
678     default:
679 	message = "Unknown network selection error";
680     }
681     /* LINTED const castaway */
682     return ((char *)message);
683 }
684 
685 /*
686  * Prints a message onto standard error describing the reason for failure.
687  */
688 void
689 nc_perror(s)
690 	const char *s;
691 {
692     fprintf(stderr, "%s: %s\n", s, nc_sperror());
693 }
694 
695 /*
696  * Duplicates the matched netconfig buffer.
697  */
698 static struct netconfig *
699 dup_ncp(ncp)
700 struct netconfig	*ncp;
701 {
702     struct netconfig	*p;
703     char	*tmp;
704     u_int	i;
705 
706     if ((tmp=malloc(MAXNETCONFIGLINE)) == NULL)
707 	return(NULL);
708     if ((p=(struct netconfig *)malloc(sizeof(struct netconfig))) == NULL) {
709 	free(tmp);
710 	return(NULL);
711     }
712     /*
713      * First we dup all the data from matched netconfig buffer.  Then we
714      * adjust some of the member pointer to a pre-allocated buffer where
715      * contains part of the data.
716      * To follow the convention used in parse_ncp(), we store all the
717      * necessary information in the pre-allocated buffer and let each
718      * of the netconfig char pointer member point to the right address
719      * in the buffer.
720      */
721     *p = *ncp;
722     p->nc_netid = (char *)strcpy(tmp,ncp->nc_netid);
723     tmp = strchr(tmp, '\0') + 1;
724     p->nc_protofmly = (char *)strcpy(tmp,ncp->nc_protofmly);
725     tmp = strchr(tmp, '\0') + 1;
726     p->nc_proto = (char *)strcpy(tmp,ncp->nc_proto);
727     tmp = strchr(tmp, '\0') + 1;
728     p->nc_device = (char *)strcpy(tmp,ncp->nc_device);
729     p->nc_lookups = (char **)malloc((size_t)(p->nc_nlookups+1) * sizeof(char *));
730     if (p->nc_lookups == NULL) {
731 	free(p->nc_netid);
732 	free(p);
733 	return(NULL);
734     }
735     for (i=0; i < p->nc_nlookups; i++) {
736     	tmp = strchr(tmp, '\0') + 1;
737     	p->nc_lookups[i] = (char *)strcpy(tmp,ncp->nc_lookups[i]);
738     }
739     return(p);
740 }
741