getgrent.c revision 10521 
1/*
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)getgrent.c	8.2 (Berkeley) 3/21/94";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/types.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <grp.h>
43
44static FILE *_gr_fp;
45static struct group _gr_group;
46static int _gr_stayopen;
47static int grscan(), start_gr();
48#ifdef YP
49#include <rpc/rpc.h>
50#include <rpcsvc/yp_prot.h>
51#include <rpcsvc/ypclnt.h>
52static int _gr_stepping_yp;
53static int _gr_yp_enabled;
54static int _getypgroup(struct group *, const char *, char *);
55static int _nextypgroup(struct group *);
56#endif
57
58#define	MAXGRP		200
59static char *members[MAXGRP];
60#define	MAXLINELENGTH	1024
61static char line[MAXLINELENGTH];
62
63struct group *
64getgrent()
65{
66	if (!_gr_fp && !start_gr()) {
67		return NULL;
68	}
69
70#ifdef YP
71	if (_gr_stepping_yp) {
72		if (_nextypgroup(&_gr_group))
73			return(&_gr_group);
74	}
75tryagain:
76#endif
77
78	if (!grscan(0, 0, NULL))
79		return(NULL);
80#ifdef YP
81	if(_gr_group.gr_name[0] == '+' && _gr_group.gr_name[1]) {
82		_getypgroup(&_gr_group, &_gr_group.gr_name[1],
83			    "group.byname");
84	} else if(_gr_group.gr_name[0] == '+') {
85		if (!_nextypgroup(&_gr_group))
86			goto tryagain;
87		else
88			return(&_gr_group);
89	}
90#endif
91	return(&_gr_group);
92}
93
94struct group *
95getgrnam(name)
96	const char *name;
97{
98	int rval;
99
100	if (!start_gr())
101		return(NULL);
102	rval = grscan(1, 0, name);
103#ifdef YP
104	if(!rval && (_gr_yp_enabled < 0 || (_gr_yp_enabled &&
105					_gr_group.gr_name[0] == '+'))) {
106		rval = _getypgroup(&_gr_group, name, "group.byname");
107	}
108#endif
109	if (!_gr_stayopen)
110		endgrent();
111	return(rval ? &_gr_group : NULL);
112}
113
114struct group *
115#ifdef __STDC__
116getgrgid(gid_t gid)
117#else
118getgrgid(gid)
119	gid_t gid;
120#endif
121{
122	int rval;
123
124	if (!start_gr())
125		return(NULL);
126	rval = grscan(1, gid, NULL);
127#ifdef YP
128	if(!rval && _gr_yp_enabled) {
129		char buf[16];
130		snprintf(buf, sizeof buf, "%d", (unsigned)gid);
131		rval = _getypgroup(&_gr_group, buf, "group.bygid");
132	}
133#endif
134	if (!_gr_stayopen)
135		endgrent();
136	return(rval ? &_gr_group : NULL);
137}
138
139static int
140start_gr()
141{
142	if (_gr_fp) {
143		rewind(_gr_fp);
144		return(1);
145	}
146	_gr_fp = fopen(_PATH_GROUP, "r");
147	if(!_gr_fp) return 0;
148#ifdef YP
149	/*
150	 * This is a disgusting hack, used to determine when YP is enabled.
151	 * This would be easier if we had a group database to go along with
152	 * the password database.
153	 */
154	{
155		char *line;
156		size_t linelen;
157		_gr_yp_enabled = 0;
158		while(line = fgetln(_gr_fp, &linelen)) {
159			if(line[0] == '+') {
160				if(line[1] && !_gr_yp_enabled) {
161					_gr_yp_enabled = 1;
162				} else {
163					_gr_yp_enabled = -1;
164					break;
165				}
166			}
167		}
168		rewind(_gr_fp);
169	}
170#endif
171	return 1;
172}
173
174int
175setgrent()
176{
177	return(setgroupent(0));
178}
179
180int
181setgroupent(stayopen)
182	int stayopen;
183{
184	if (!start_gr())
185		return(0);
186	_gr_stayopen = stayopen;
187#ifdef YP
188	_gr_stepping_yp = 0;
189#endif
190	return(1);
191}
192
193void
194endgrent()
195{
196#ifdef YP
197	_gr_stepping_yp = 0;
198#endif
199	if (_gr_fp) {
200		(void)fclose(_gr_fp);
201		_gr_fp = NULL;
202	}
203}
204
205static int
206grscan(search, gid, name)
207	register int search, gid;
208	register char *name;
209{
210	register char *cp, **m;
211	char *bp;
212	char *fgets(), *strsep(), *index();
213
214	for (;;) {
215		if (!fgets(line, sizeof(line), _gr_fp))
216			return(0);
217		bp = line;
218		/* skip lines that are too big */
219		if (!index(line, '\n')) {
220			int ch;
221
222			while ((ch = getc(_gr_fp)) != '\n' && ch != EOF)
223				;
224			continue;
225		}
226		_gr_group.gr_name = strsep(&bp, ":\n");
227		if (search && name) {
228#ifdef YP
229			if(_gr_group.gr_name[0] == '+') {
230				if(strcmp(&_gr_group.gr_name[1], name)) {
231					continue;
232				}
233				return _getypgroup(&_gr_group, name,
234						   "group.byname");
235			}
236#endif /* YP */
237			if(strcmp(_gr_group.gr_name, name)) {
238				continue;
239			}
240		}
241#ifdef YP
242		/*
243		 * XXX   We need to be careful to avoid proceeding
244		 * past this point under certain circumstances or
245		 * we risk dereferencing null pointers down below.
246		 */
247		if (_gr_group.gr_name[0] == '+') {
248			switch(search) {
249				case 0:
250					return(1);
251				case 1:
252					return(0);
253				default:
254					return(0);
255			}
256		}
257#endif /* YP */
258		_gr_group.gr_passwd = strsep(&bp, ":\n");
259		if (!(cp = strsep(&bp, ":\n")))
260			continue;
261		_gr_group.gr_gid = atoi(cp);
262		if (search && name == NULL && _gr_group.gr_gid != gid)
263			continue;
264		cp = NULL;
265		for (m = _gr_group.gr_mem = members;; bp++) {
266			if (m == &members[MAXGRP - 1])
267				break;
268			if (*bp == ',') {
269				if (cp) {
270					*bp = '\0';
271					*m++ = cp;
272					cp = NULL;
273				}
274			} else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
275				if (cp) {
276					*bp = '\0';
277					*m++ = cp;
278			}
279				break;
280			} else if (cp == NULL)
281				cp = bp;
282		}
283		*m = NULL;
284		return(1);
285	}
286	/* NOTREACHED */
287}
288
289#ifdef YP
290
291static int
292_gr_breakout_yp(struct group *gr, char *result)
293{
294	char *s, *cp;
295	char **m;
296
297	/*
298	 * XXX If 's' ends up being a NULL pointer, punt on this group.
299	 * It means the NIS group entry is badly formatted and should
300	 * be skipped.
301	 */
302	if ((s = strsep(&result, ":")) == NULL) return 0; /* name */
303	gr->gr_name = s;
304
305	if ((s = strsep(&result, ":")) == NULL) return 0; /* password */
306	gr->gr_passwd = s;
307
308	if ((s = strsep(&result, ":")) == NULL) return 0; /* gid */
309	gr->gr_gid = atoi(s);
310
311	if ((s = result) == NULL) return 0;
312	cp = 0;
313
314	for (m = _gr_group.gr_mem = members; /**/; s++) {
315		if (m == &members[MAXGRP - 1]) {
316			break;
317		}
318		if (*s == ',') {
319			if (cp) {
320				*s = '\0';
321				*m++ = cp;
322				cp = NULL;
323			}
324		} else if (*s == '\0' || *s == '\n' || *s == ' ') {
325			if (cp) {
326				*s = '\0';
327				*m++ = cp;
328			}
329			break;
330		} else if (cp == NULL) {
331			cp = s;
332		}
333	}
334	*m = NULL;
335
336	return 1;
337}
338
339static char *_gr_yp_domain;
340
341static int
342_getypgroup(struct group *gr, const char *name, char *map)
343{
344	char *result, *s;
345	static char resultbuf[1024];
346	int resultlen;
347
348	if(!_gr_yp_domain) {
349		if(yp_get_default_domain(&_gr_yp_domain))
350		  return 0;
351	}
352
353	if(yp_match(_gr_yp_domain, map, name, strlen(name),
354		    &result, &resultlen))
355		return 0;
356
357	s = strchr(result, '\n');
358	if(s) *s = '\0';
359
360	if(resultlen >= sizeof resultbuf) return 0;
361	strcpy(resultbuf, result);
362	result = resultbuf;
363	return(_gr_breakout_yp(gr, resultbuf));
364
365}
366
367
368static int
369_nextypgroup(struct group *gr)
370{
371	static char *key;
372	static int keylen;
373	char *lastkey, *result;
374	static char resultbuf[1024];
375	int resultlen;
376	int rv;
377
378	if(!_gr_yp_domain) {
379		if(yp_get_default_domain(&_gr_yp_domain))
380		  return 0;
381	}
382
383	if(!_gr_stepping_yp) {
384		if(key) free(key);
385		rv = yp_first(_gr_yp_domain, "group.byname",
386			      &key, &keylen, &result, &resultlen);
387		if(rv) {
388			return 0;
389		}
390		_gr_stepping_yp = 1;
391		goto unpack;
392	} else {
393tryagain:
394		lastkey = key;
395		rv = yp_next(_gr_yp_domain, "group.byname", key, keylen,
396			     &key, &keylen, &result, &resultlen);
397		free(lastkey);
398unpack:
399		if(rv) {
400			_gr_stepping_yp = 0;
401			return 0;
402		}
403
404		if(resultlen > sizeof(resultbuf)) {
405			free(result);
406			goto tryagain;
407		}
408
409		strcpy(resultbuf, result);
410		free(result);
411		if(result = strchr(resultbuf, '\n')) *result = '\0';
412		return(_gr_breakout_yp(gr, resultbuf));
413	}
414}
415
416#endif /* YP */
417