getgrent.c

早期freebsd实现

/*
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getgrent.c	8.2 (Berkeley) 3/21/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <grp.h>

static FILE *_gr_fp;
static struct group _gr_group;
static int _gr_stayopen;
static int grscan(), start_gr();

#define	MAXGRP		200
static char *members[MAXGRP];
#define	MAXLINELENGTH	1024
static char line[MAXLINELENGTH];

struct group *
getgrent()
{
	if (!_gr_fp && !start_gr() || !grscan(0, 0, NULL))
		return(NULL);
	return(&_gr_group);
}

struct group *
getgrnam(name)
	const char *name;
{
	int rval;

	if (!start_gr())
		return(NULL);
	rval = grscan(1, 0, name);
	if (!_gr_stayopen)
		endgrent();
	return(rval ? &_gr_group : NULL);
}

struct group *
#ifdef __STDC__
getgrgid(gid_t gid)
#else
getgrgid(gid)
	gid_t gid;
#endif
{
	int rval;

	if (!start_gr())
		return(NULL);
	rval = grscan(1, gid, NULL);
	if (!_gr_stayopen)
		endgrent();
	return(rval ? &_gr_group : NULL);
}

static
start_gr()
{
	if (_gr_fp) {
		rewind(_gr_fp);
		return(1);
	}
	return((_gr_fp = fopen(_PATH_GROUP, "r")) ? 1 : 0);
}

int
setgrent()
{
	return(setgroupent(0));
}

int
setgroupent(stayopen)
	int stayopen;
{
	if (!start_gr())
		return(0);
	_gr_stayopen = stayopen;
	return(1);
}

void
endgrent()
{
	if (_gr_fp) {
		(void)fclose(_gr_fp);
		_gr_fp = NULL;
	}
}

static
grscan(search, gid, name)
	register int search, gid;
	register char *name;
{
	register char *cp, **m;
	char *bp;
	char *fgets(), *strsep(), *index();

	for (;;) {
		if (!fgets(line, sizeof(line), _gr_fp))
			return(0);
		bp = line;
		/* skip lines that are too big */
		if (!index(line, '\n')) {
			int ch;

			while ((ch = getc(_gr_fp)) != '\n' && ch != EOF)
				;
			continue;
		}
		_gr_group.gr_name = strsep(&bp, ":\n");
		if (search && name && strcmp(_gr_group.gr_name, name))
			continue;
		_gr_group.gr_passwd = strsep(&bp, ":\n");
		if (!(cp = strsep(&bp, ":\n")))
			continue;
		_gr_group.gr_gid = atoi(cp);
		if (search && name == NULL && _gr_group.gr_gid != gid)
			continue;
		cp = NULL;
		for (m = _gr_group.gr_mem = members;; bp++) {
			if (m == &members[MAXGRP - 1])
				break;
			if (*bp == ',') {
				if (cp) {
					*bp = '\0';
					*m++ = cp;
					cp = NULL;
				}
			} else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
				if (cp) {
					*bp = '\0';
					*m++ = cp;
			}
				break;
			} else if (cp == NULL)
				cp = bp;
		}
		*m = NULL;
		return(1);
	}
	/* NOTREACHED */
}