1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright (c) 1997-2001 by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28/*	  All Rights Reserved  	*/
29
30/*
31 * Copyright (c) 2013 RackTop Systems.
32 */
33
34#include <errno.h>
35#include <sys/types.h>
36#include <stdio.h>
37#include <userdefs.h>
38#include <pwd.h>
39#include <libcmdutils.h>
40
41static int findunuseduid(uid_t start, uid_t stop, uid_t *ret);
42static boolean_t isreserveduid(uid_t uid);
43
44/*
45 * Find the highest unused uid. If the highest unused uid is "stop",
46 * then attempt to find a hole in the range. Returns 0 on success.
47 */
48int
49findnextuid(uid_t start, uid_t stop, uid_t *ret)
50{
51	uid_t uid = start;
52	struct passwd *pwd;
53	boolean_t overflow = B_FALSE;
54
55	setpwent();
56	for (pwd = getpwent(); pwd != NULL; pwd = getpwent()) {
57		if (isreserveduid(pwd->pw_uid))		/* Skip reserved IDs */
58			continue;
59		if (pwd->pw_uid >= uid) {
60			if (pwd->pw_uid == stop) {	/* Overflow check */
61				overflow = B_TRUE;
62				break;
63			}
64			uid = pwd->pw_uid + 1;
65		}
66	}
67	if (pwd == NULL && errno != 0) {
68		endpwent();
69		return (-1);
70	}
71	endpwent();
72	if (overflow == B_TRUE)				/* Find a hole */
73		return (findunuseduid(start, stop, ret));
74	while (isreserveduid(uid) && uid < stop)	/* Skip reserved IDs */
75		uid++;
76	*ret = uid;
77	return (0);
78}
79
80/*
81 * Check to see whether the uid is a reserved uid
82 * -- nobody, noaccess or nobody4
83 */
84static boolean_t
85isreserveduid(uid_t uid)
86{
87	return (uid == 60001 || uid == 60002 || uid == 65534);
88}
89
90/*
91 * findunuseduid() attempts to return the next valid usable id between the
92 * supplied upper and lower limits. Returns 0 on success.
93 */
94static int
95findunuseduid(uid_t start, uid_t stop, uid_t *ret)
96{
97	uid_t uid;
98
99	for (uid = start; uid <= stop; uid++) {
100		if (isreserveduid(uid))
101			continue;
102		if (getpwuid(uid) == NULL) {
103			if (errno != 0)
104				return (-1);
105			break;
106		}
107	}
108	if (uid > stop)
109		return (-1);
110	*ret = uid;
111	return (0);
112}
113