issubdir.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1989 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* University Copyright- Copyright (c) 1982, 1986, 1988
* The Regents of the University of California
* All Rights Reserved
*
* University Acknowledgment- Portions of this document are derived from
* software developed by the University of California, Berkeley, and its
* contributors.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Subdirectory detection: needed by exportfs and rpc.mountd.
* The above programs call issubdir() frequently, so we make
* it fast by caching the results of stat().
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <string.h>
#define MAXSTATS MAXPATHLEN/2 /* maximum number of stat()'s to save */
#define inoeq(ino1, ino2) ((ino1) == (ino2))
#define deveq(dev1, dev2) ((dev1) == (dev2))
/*
* dir1 is a subdirectory of dir2 within the same filesystem if
* (a) dir1 is identical to dir2
* (b) dir1's parent is dir2
*/
issubdir(dir1, dir2)
char *dir1;
char *dir2;
{
struct stat st;
struct stat parent_st;
char *p;
int index;
static dev_t child_dev;
static dev_t child_rdev;
static ino_t child_ino[MAXSTATS];
static int valid;
static char childdir[MAXPATHLEN];
static char child_fstype[_ST_FSTYPSZ];
/*
* Get parent directory info
*/
if (stat(dir2, &parent_st) < 0) {
return (0);
}
if (strcmp(childdir, dir1) != 0) {
/*
* Not in cache: get child directory info
*/
p = strcpy(childdir, dir1) + strlen(dir1);
index = 0;
valid = 0;
for (;;) {
if (stat(childdir, &st) < 0) {
childdir[0] = 0; /* invalidate cache */
return (0);
}
if (index == 0) {
child_dev = st.st_dev;
child_rdev = st.st_rdev;
(void) strncpy(child_fstype, st.st_fstype,
sizeof (child_fstype));
}
if (index > 0 &&
(child_dev != st.st_dev ||
inoeq(child_ino[index - 1], st.st_ino))) {
/*
* Hit root: done
*/
break;
}
child_ino[index++] = st.st_ino;
if (st.st_mode & S_IFDIR) {
p = strcpy(p, "/..") + 3;
} else {
p = strrchr(childdir, '/');
if (p == NULL) {
p = strcpy(childdir, ".") + 1;
} else {
while (((p - 1) > childdir) &&
*(p - 1) == '/') {
p--;
}
*p = '\0';
}
}
}
valid = index;
(void) strcpy(childdir, dir1);
}
/*
* Perform the test
*/
if (!deveq(parent_st.st_dev, child_dev)) {
return (0);
}
/*
* Check rdev also in case of lofs
*/
if (((strcmp(parent_st.st_fstype, "lofs") == 0)) &&
(strcmp(child_fstype, "lofs") == 0)) {
if (!deveq(parent_st.st_rdev, child_rdev)) {
return (0);
}
}
for (index = 0; index < valid; index++) {
if (inoeq(child_ino[index], parent_st.st_ino)) {
return (1);
}
}
return (0);
}