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 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * University Copyright- Copyright (c) 1982, 1986, 1988
32 * The Regents of the University of California
33 * All Rights Reserved
34 *
35 * University Acknowledgment- Portions of this document are derived from
36 * software developed by the University of California, Berkeley, and its
37 * contributors.
38 */
39
40 /*
41 * Subdirectory detection: needed by exportfs and rpc.mountd.
42 * The above programs call issubdir() frequently, so we make
43 * it fast by caching the results of stat().
44 */
45 #include <sys/types.h>
46 #include <sys/param.h>
47 #include <sys/stat.h>
48 #include <string.h>
49
50 #define MAXSTATS MAXPATHLEN/2 /* maximum number of stat()'s to save */
51
52 #define inoeq(ino1, ino2) ((ino1) == (ino2))
53 #define deveq(dev1, dev2) ((dev1) == (dev2))
54
55 /*
56 * dir1 is a subdirectory of dir2 within the same filesystem if
57 * (a) dir1 is identical to dir2
58 * (b) dir1's parent is dir2
59 */
60 int
issubdir(dir1,dir2)61 issubdir(dir1, dir2)
62 char *dir1;
63 char *dir2;
64 {
65 struct stat st;
66 struct stat parent_st;
67 char *p;
68 int index;
69
70 static dev_t child_dev;
71 static dev_t child_rdev;
72 static ino_t child_ino[MAXSTATS];
73 static int valid;
74 static char childdir[MAXPATHLEN];
75 static char child_fstype[_ST_FSTYPSZ];
76
77 /*
78 * Get parent directory info
79 */
80 if (stat(dir2, &parent_st) < 0) {
81 return (0);
82 }
83
84 if (strcmp(childdir, dir1) != 0) {
85 /*
86 * Not in cache: get child directory info
87 */
88 p = strcpy(childdir, dir1) + strlen(dir1);
89 index = 0;
90 valid = 0;
91 for (;;) {
92 if (stat(childdir, &st) < 0) {
93 childdir[0] = 0; /* invalidate cache */
94 return (0);
95 }
96 if (index == 0) {
97 child_dev = st.st_dev;
98 child_rdev = st.st_rdev;
99 (void) strncpy(child_fstype, st.st_fstype,
100 sizeof (child_fstype));
101 }
102 if (index > 0 &&
103 (child_dev != st.st_dev ||
104 inoeq(child_ino[index - 1], st.st_ino))) {
105 /*
106 * Hit root: done
107 */
108 break;
109 }
110 child_ino[index++] = st.st_ino;
111 if (S_ISDIR(st.st_mode)) {
112 p = strcpy(p, "/..") + 3;
113 } else {
114 p = strrchr(childdir, '/');
115 if (p == NULL) {
116 p = strcpy(childdir, ".") + 1;
117 } else {
118 while (((p - 1) > childdir) &&
119 *(p - 1) == '/') {
120 p--;
121 }
122 *p = '\0';
123 }
124 }
125 }
126 valid = index;
127 (void) strcpy(childdir, dir1);
128 }
129
130 /*
131 * Perform the test
132 */
133 if (!deveq(parent_st.st_dev, child_dev)) {
134 return (0);
135 }
136
137 /*
138 * Check rdev also in case of lofs
139 */
140 if (((strcmp(parent_st.st_fstype, "lofs") == 0)) &&
141 (strcmp(child_fstype, "lofs") == 0)) {
142 if (!deveq(parent_st.st_rdev, child_rdev)) {
143 return (0);
144 }
145 }
146
147 for (index = 0; index < valid; index++) {
148 if (inoeq(child_ino[index], parent_st.st_ino)) {
149 return (1);
150 }
151 }
152 return (0);
153 }
154