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 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