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 #pragma ident "%Z%%M% %I% %E% SMI" /* SVr4.0 1.5 */
32
33 #include <sys/types.h>
34 #include <stdio.h>
35 #include <userdefs.h>
36 #include <pwd.h>
37
38 #include <sys/param.h>
39 #ifndef MAXUID
40 #include <limits.h>
41 #ifdef UID_MAX
42 #define MAXUID UID_MAX
43 #else
44 #define MAXUID 60000
45 #endif
46 #endif
47
48 static uid_t getrangeboundid(uid_t start, uid_t stop);
49 static int isreserveduid(uid_t uid);
50
51 /*
52 * Find the highest uid currently in use and return it. If the highest unused
53 * uid is MAXUID, then attempt to find a hole in the range. If there are no
54 * more unused uids, then return -1.
55 */
56 uid_t
findnextuid(void)57 findnextuid(void)
58 {
59 uid_t uid = DEFRID + 1;
60 struct passwd *pwd;
61 uchar_t overflow = 0;
62
63 setpwent();
64 for (pwd = getpwent(); pwd != NULL; pwd = getpwent()) {
65 if (isreserveduid(pwd->pw_uid)) /* Skip reserved IDs */
66 continue;
67 if (pwd->pw_uid >= uid) {
68 if (pwd->pw_uid == MAXUID) { /* Overflow check */
69 overflow = 1;
70 break;
71 }
72 uid = pwd->pw_uid + 1;
73 while (isreserveduid(uid) &&
74 uid < MAXUID) { /* Skip reserved IDs */
75 uid++;
76 }
77 }
78 }
79 endpwent();
80 if (overflow == 1) /* Find a hole */
81 return (getrangeboundid(DEFRID + 1, MAXUID));
82 return (uid);
83 }
84
85 /*
86 * Check to see that the uid is a reserved uid
87 * -- nobody, noaccess or nobody4
88 */
89 static int
isreserveduid(uid_t uid)90 isreserveduid(uid_t uid)
91 {
92 return (uid == 60001 || uid == 60002 || uid == 65534);
93 }
94
95
96 /*
97 * getrangeboundid() attempts to return the next valid usable id between the
98 * supplied upper and lower limits. If these limits exceed the system
99 * boundaries of DEFRID +1 and MAXUID (lower and upper bound respectively),
100 * then they are ignored and DEFRID + 1 and MAXUID are used.
101 *
102 * Returns a valid uid_t between DEFRID +1 and MAXUID, -1 is returned on fail
103 */
104 static uid_t
getrangeboundid(uid_t start,uid_t stop)105 getrangeboundid(uid_t start, uid_t stop)
106 {
107 uid_t low = (start <= DEFRID) ? DEFRID + 1 : start;
108 uid_t high = (stop < MAXUID) ? stop : MAXUID;
109 uid_t uid;
110
111 for (uid = low; uid <= high; uid++) {
112 if (isreserveduid(uid))
113 continue;
114 if (getpwuid(uid) == NULL)
115 break;
116 }
117 return ((uid > high) ? -1 : uid);
118 }
119