source: rtems/cpukit/libmisc/shell/pwcache.c

/*
 * 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.
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)pwcache.c   8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/lib/libc/gen/pwcache.c,v 1.11 2007/01/09 00:27:55 imp Exp $");

#include <sys/types.h>

#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>

#include "internal.h"

#define UT_NAMESIZE 64

#define NCACHE  64                      /* power of 2 */
#define MASK    (NCACHE - 1)            /* bits to store with */

const char *
user_from_uid(uid_t uid, int nouser)
{
        static struct ncache {
                uid_t   uid;
                int     found;
                char    name[UT_NAMESIZE + 1];
        } c_uid[NCACHE];
        static int pwopen;
        struct passwd *pw;
        struct ncache *cp;

        cp = c_uid + (uid & MASK);
        if (cp->uid != uid || !*cp->name) {
                if (pwopen == 0) {
                        //setpassent(1);
                        pwopen = 1;
                }
                pw = getpwuid(uid);
                cp->uid = uid;
                if (pw != NULL) {
                        cp->found = 1;
                        (void)strncpy(cp->name, pw->pw_name, UT_NAMESIZE);
                        cp->name[UT_NAMESIZE] = '\0';
                } else {
                        cp->found = 0;
                        (void)snprintf(cp->name, UT_NAMESIZE, "%u", uid);
                        if (nouser)
                                return (NULL);
                }
        }
        return ((nouser && !cp->found) ? NULL : cp->name);
}

char *
group_from_gid(gid_t gid, int nogroup)
{
        static struct ncache {
                gid_t   gid;
                int     found;
                char    name[UT_NAMESIZE + 1];
        } c_gid[NCACHE];
        static int gropen;
        struct group *gr;
        struct ncache *cp;

        cp = c_gid + (gid & MASK);
        if (cp->gid != gid || !*cp->name) {
                if (gropen == 0) {
                        //setgroupent(1);
                        gropen = 1;
                }
                gr = getgrgid(gid);
                cp->gid = gid;
                if (gr != NULL) {
                        cp->found = 1;
                        (void)strncpy(cp->name, gr->gr_name, UT_NAMESIZE);
                        cp->name[UT_NAMESIZE] = '\0';
                } else {
                        cp->found = 0;
                        (void)snprintf(cp->name, UT_NAMESIZE, "%u", gid);
                        if (nogroup)
                                return (NULL);
                }
        }
        return ((nogroup && !cp->found) ? NULL : cp->name);
}