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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
27 /* All Rights Reserved */
28
29 /*
30 * Copyright (c) 2013 RackTop Systems.
31 */
32
33 #include <errno.h>
34 #include <sys/types.h>
35 #include <stdio.h>
36 #include <userdefs.h>
37 #include <grp.h>
38 #include <libcmdutils.h>
39
40 static int findunusedgid(gid_t start, gid_t stop, gid_t *ret);
41 static boolean_t isreservedgid(gid_t gid);
42
43 /*
44 * Find the highest unused uid. If the highest unused gid is "stop",
45 * then attempt to find a hole in the range. Returns 0 on success.
46 */
47 int
findnextgid(gid_t start,gid_t stop,gid_t * ret)48 findnextgid(gid_t start, gid_t stop, gid_t *ret)
49 {
50 gid_t gid = start;
51 struct group *grp;
52 boolean_t overflow = B_FALSE;
53
54 setgrent();
55 for (grp = getgrent(); grp != NULL; grp = getgrent()) {
56 if (isreservedgid(grp->gr_gid)) /* Skip reserved IDs */
57 continue;
58 if (grp->gr_gid >= gid) {
59 if (grp->gr_gid == stop) { /* Overflow check */
60 overflow = B_TRUE;
61 break;
62 }
63 gid = grp->gr_gid + 1;
64 }
65 }
66 if (grp == NULL && errno != 0) {
67 endgrent();
68 return (-1);
69 }
70 endgrent();
71 if (overflow == B_TRUE) /* Find a hole */
72 return (findunusedgid(start, stop, ret));
73 while (isreservedgid(gid) && gid < stop) /* Skip reserved IDs */
74 gid++;
75 *ret = gid;
76 return (0);
77 }
78
79 /*
80 * Check to see whether the gid is a reserved gid
81 * -- nobody, noaccess or nogroup
82 */
83 static boolean_t
isreservedgid(gid_t gid)84 isreservedgid(gid_t gid)
85 {
86 return (gid == 60001 || gid == 60002 || gid == 65534);
87 }
88
89 /*
90 * findunusedgid() attempts to return the next valid usable id between the
91 * supplied upper and lower limits. Returns 0 on success.
92 */
93 static int
findunusedgid(gid_t start,gid_t stop,gid_t * ret)94 findunusedgid(gid_t start, gid_t stop, gid_t *ret)
95 {
96 gid_t gid;
97
98 for (gid = start; gid <= stop; gid++) {
99 if (isreservedgid(gid))
100 continue;
101 if (getgrgid(gid) == NULL) {
102 if (errno != 0)
103 return (-1);
104 break;
105 }
106 }
107 if (gid > stop)
108 return (-1);
109 *ret = gid;
110 return (0);
111 }
112