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getgrent.c revision 1.4 
      1 /*	$NetBSD: getgrent.c,v 1.4 2001/06/15 17:26:51 tsutsui Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  * Portions Copyright (c) 1994, Jason Downs. All Rights Reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by the University of
     19  *	California, Berkeley and its contributors.
     20  * 4. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 /*
     38  * Copied from:  lib/libc/gen/getgrent.c
     39  * and then gutted, leaving only /etc/group support.
     40  */
     41 
     42 #include <sys/cdefs.h>
     43 
     44 #ifdef __weak_alias
     45 #define endgrent		_endgrent
     46 #define getgrent		_getgrent
     47 #define getgrgid		_getgrgid
     48 #define getgrnam		_getgrnam
     49 #define setgrent		_setgrent
     50 #define setgroupent		_setgroupent
     51 #endif
     52 
     53 #include <sys/types.h>
     54 #include <stdio.h>
     55 #include <stdlib.h>
     56 #include <string.h>
     57 #include <grp.h>
     58 
     59 #ifdef __weak_alias
     60 __weak_alias(endgrent,_endgrent)
     61 __weak_alias(getgrent,_getgrent)
     62 __weak_alias(getgrgid,_getgrgid)
     63 __weak_alias(getgrnam,_getgrnam)
     64 __weak_alias(setgrent,_setgrent)
     65 __weak_alias(setgroupent,_setgroupent)
     66 #endif
     67 
     68 static FILE *_gr_fp;
     69 static struct group _gr_group;
     70 static int _gr_stayopen;
     71 static int grscan __P((int, int, const char *));
     72 static int start_gr __P((void));
     73 
     74 #define	MAXGRP		200
     75 static char *members[MAXGRP];
     76 #define	MAXLINELENGTH	1024
     77 static char line[MAXLINELENGTH];
     78 
     79 struct group *
     80 getgrent()
     81 {
     82 	if ((!_gr_fp && !start_gr()) || !grscan(0, 0, NULL))
     83 		return(NULL);
     84 	return(&_gr_group);
     85 }
     86 
     87 struct group *
     88 getgrnam(name)
     89 	const char *name;
     90 {
     91 	int rval;
     92 
     93 	if (!start_gr())
     94 		return(NULL);
     95 	rval = grscan(1, 0, name);
     96 	if (!_gr_stayopen)
     97 		endgrent();
     98 	return(rval ? &_gr_group : NULL);
     99 }
    100 
    101 struct group *
    102 #ifdef __STDC__
    103 getgrgid(gid_t gid)
    104 #else
    105 getgrgid(gid)
    106 	gid_t gid;
    107 #endif
    108 {
    109 	int rval;
    110 
    111 	if (!start_gr())
    112 		return(NULL);
    113 	rval = grscan(1, gid, NULL);
    114 	if (!_gr_stayopen)
    115 		endgrent();
    116 	return(rval ? &_gr_group : NULL);
    117 }
    118 
    119 static int
    120 start_gr()
    121 {
    122 	if (_gr_fp) {
    123 		rewind(_gr_fp);
    124 		return(1);
    125 	}
    126 	return((_gr_fp = fopen(_PATH_GROUP, "r")) ? 1 : 0);
    127 }
    128 
    129 void
    130 setgrent()
    131 {
    132 	(void) setgroupent(0);
    133 }
    134 
    135 int
    136 setgroupent(stayopen)
    137 	int stayopen;
    138 {
    139 	if (!start_gr())
    140 		return(0);
    141 	_gr_stayopen = stayopen;
    142 	return(1);
    143 }
    144 
    145 void
    146 endgrent()
    147 {
    148 	if (_gr_fp) {
    149 		(void)fclose(_gr_fp);
    150 		_gr_fp = NULL;
    151 	}
    152 }
    153 
    154 static int
    155 grscan(search, gid, name)
    156 	register int search, gid;
    157 	register const char *name;
    158 {
    159 	register char *cp, **m;
    160 	char *bp;
    161 
    162 	for (;;) {
    163 		if (!fgets(line, sizeof(line), _gr_fp))
    164 			return(0);
    165 		bp = line;
    166 		/* skip lines that are too big */
    167 		if (!strchr(line, '\n')) {
    168 			int ch;
    169 
    170 			while ((ch = getc(_gr_fp)) != '\n' && ch != EOF)
    171 				;
    172 			continue;
    173 		}
    174 		_gr_group.gr_name = strsep(&bp, ":\n");
    175 		if (search && name && strcmp(_gr_group.gr_name, name))
    176 			continue;
    177 		_gr_group.gr_passwd = strsep(&bp, ":\n");
    178 		if (!(cp = strsep(&bp, ":\n")))
    179 			continue;
    180 		_gr_group.gr_gid = atoi(cp);
    181 		if (search && name == NULL && _gr_group.gr_gid != gid)
    182 			continue;
    183 		cp = NULL;
    184 		if (bp == NULL)
    185 			continue;
    186 		for (m = _gr_group.gr_mem = members;; bp++) {
    187 			if (m == &members[MAXGRP - 1])
    188 				break;
    189 			if (*bp == ',') {
    190 				if (cp) {
    191 					*bp = '\0';
    192 					*m++ = cp;
    193 					cp = NULL;
    194 				}
    195 			} else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
    196 				if (cp) {
    197 					*bp = '\0';
    198 					*m++ = cp;
    199 				}
    200 				break;
    201 			} else if (cp == NULL)
    202 				cp = bp;
    203 		}
    204 		*m = NULL;
    205 		return(1);
    206 	}
    207 	/* NOTREACHED */
    208 }
    209