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(char * dir1,char * dir2)61 issubdir(char *dir1, char *dir2)
62 {
63 struct stat st;
64 struct stat parent_st;
65 char *p;
66 int index;
67
68 static dev_t child_dev;
69 static dev_t child_rdev;
70 static ino_t child_ino[MAXSTATS];
71 static int valid;
72 static char childdir[MAXPATHLEN];
73 static char child_fstype[_ST_FSTYPSZ];
74
75 /*
76 * Get parent directory info
77 */
78 if (stat(dir2, &parent_st) < 0) {
79 return (0);
80 }
81
82 if (strcmp(childdir, dir1) != 0) {
83 /*
84 * Not in cache: get child directory info
85 */
86 p = strcpy(childdir, dir1) + strlen(dir1);
87 index = 0;
88 valid = 0;
89 for (;;) {
90 if (stat(childdir, &st) < 0) {
91 childdir[0] = 0; /* invalidate cache */
92 return (0);
93 }
94 if (index == 0) {
95 child_dev = st.st_dev;
96 child_rdev = st.st_rdev;
97 (void) strncpy(child_fstype, st.st_fstype,
98 sizeof (child_fstype));
99 }
100 if (index > 0 &&
101 (child_dev != st.st_dev ||
102 inoeq(child_ino[index - 1], st.st_ino))) {
103 /*
104 * Hit root: done
105 */
106 break;
107 }
108 child_ino[index++] = st.st_ino;
109 if (S_ISDIR(st.st_mode)) {
110 p = strcpy(p, "/..") + 3;
111 } else {
112 p = strrchr(childdir, '/');
113 if (p == NULL) {
114 p = strcpy(childdir, ".") + 1;
115 } else {
116 while (((p - 1) > childdir) &&
117 *(p - 1) == '/') {
118 p--;
119 }
120 *p = '\0';
121 }
122 }
123 }
124 valid = index;
125 (void) strlcpy(childdir, dir1, MAXPATHLEN);
126 }
127
128 /*
129 * Perform the test
130 */
131 if (!deveq(parent_st.st_dev, child_dev)) {
132 return (0);
133 }
134
135 /*
136 * Check rdev also in case of lofs
137 */
138 if (((strcmp(parent_st.st_fstype, "lofs") == 0)) &&
139 (strcmp(child_fstype, "lofs") == 0)) {
140 if (!deveq(parent_st.st_rdev, child_rdev)) {
141 return (0);
142 }
143 }
144
145 for (index = 0; index < valid; index++) {
146 if (inoeq(child_ino[index], parent_st.st_ino)) {
147 return (1);
148 }
149 }
150 return (0);
151 }
152