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(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