port/gen/getpw.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1988 AT&T */
/*    All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "lint.h"
#include "file64.h"
#include <sys/types.h>
#include <mtlib.h>
#include <ctype.h>
#include <thread.h>
#include <synch.h>
#include <stdio.h>
#include "stdiom.h"
#include "libc.h"

static FILE *pwf;
static mutex_t _pwlock = DEFAULTMUTEX;
const char *PASSWD = "/etc/passwd";

int
getpw(uid_t uid, char buf[])
{
    int n, c;
    char *bp;
    FILE *fp;
    rmutex_t *lk;

    if (pwf == NULL) {
        fp = fopen(PASSWD, "rF");
        lmutex_lock(&_pwlock);
        if (pwf == NULL) {
            if ((pwf = fp) == NULL) {
                lmutex_unlock(&_pwlock);
                return (1);
            }
            fp = NULL;
        }
        lmutex_unlock(&_pwlock);
        if (fp != NULL)     /* someone beat us to it */
            (void) fclose(fp);
    }

    FLOCKFILE(lk, pwf);
    _rewind_unlocked(pwf);

    for (;;) {
        bp = buf;
        while ((c = GETC(pwf)) != '\n') {
            if (c == EOF) {
                FUNLOCKFILE(lk);
                return (1);
            }
            *bp++ = (char)c;
        }
        *bp = '\0';
        bp = buf;
        n = 3;
        while (--n)
            while ((c = *bp++) != ':')
                if (c == '\n') {
                    FUNLOCKFILE(lk);
                    return (1);
                }
        while ((c = *bp++) != ':')
            if (isdigit(c))
                n = n*10+c-'0';
            else
                continue;
        if (n == uid) {
            FUNLOCKFILE(lk);
            return (0);
        }
    }
}