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
41 static int findunuseduid(uid_t start, uid_t stop, uid_t *ret);
42 static 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 */
48 int
findnextuid(uid_t start,uid_t stop,uid_t * ret)49 findnextuid(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 */
84 static boolean_t
isreserveduid(uid_t uid)85 isreserveduid(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 */
94 static int
findunuseduid(uid_t start,uid_t stop,uid_t * ret)95 findunuseduid(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