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/* $OpenBSD: compat_util.c,v 1.5 1996/12/08 14:25:46 niklas Exp $ */
/* $NetBSD: compat_util.c,v 1.4 1996/03/14 19:31:45 christos Exp $ */
/*
* Copyright (c) 1994 Christos Zoulas
* Copyright (c) 1995 Frank van der Linden
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <compat/common/compat_util.h>
/*
* Search an alternate path before passing pathname arguments on
* to system calls. Useful for keeping a separate 'emulation tree'.
*
* If cflag is set, we check if an attempt can be made to create
* the named file, i.e. we check if the directory it should
* be in exists.
*/
int
emul_find(p, sgp, prefix, path, pbuf, cflag)
struct proc *p;
caddr_t *sgp; /* Pointer to stackgap memory */
const char *prefix;
char *path;
char **pbuf;
int cflag;
{
struct nameidata nd;
struct nameidata ndroot;
struct vattr vat;
struct vattr vatroot;
int error;
char *ptr, *buf, *cp;
const char *pr;
size_t sz, len;
buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
*pbuf = path;
for (ptr = buf, pr = prefix; (*ptr = *pr) != '\0'; ptr++, pr++)
continue;
sz = MAXPATHLEN - (ptr - buf);
/*
* If sgp is not given then the path is already in kernel space
*/
if (sgp == NULL)
error = copystr(path, ptr, sz, &len);
else
error = copyinstr(path, ptr, sz, &len);
if (error)
goto bad;
if (*ptr != '/') {
error = EINVAL;
goto bad;
}
/*
* We know that there is a / somewhere in this pathname.
* Search backwards for it, to find the file's parent dir
* to see if it exists in the alternate tree. If it does,
* and we want to create a file (cflag is set). We don't
* need to worry about the root comparison in this case.
*/
if (cflag) {
for (cp = &ptr[len] - 1; *cp != '/'; cp--)
;
*cp = '\0';
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
if ((error = namei(&nd)) != 0)
goto bad;
*cp = '/';
}
else {
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
if ((error = namei(&nd)) != 0)
goto bad;
/*
* We now compare the vnode of the emulation root to the one
* vnode asked. If they resolve to be the same, then we
* ignore the match so that the real root gets used.
* This avoids the problem of traversing "../.." to find the
* root directory and never finding it, because "/" resolves
* to the emulation root directory. This is expensive :-(
*/
/* XXX: prototype should have const here for NDINIT */
NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, prefix, p);
if ((error = namei(&ndroot)) != 0)
goto bad2;
if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0)
goto bad3;
if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p))
!= 0)
goto bad3;
if (vat.va_fsid == vatroot.va_fsid &&
vat.va_fileid == vatroot.va_fileid) {
error = ENOENT;
goto bad3;
}
}
if (sgp == NULL)
*pbuf = buf;
else {
sz = &ptr[len] - buf;
*pbuf = stackgap_alloc(sgp, sz + 1);
error = copyout(buf, *pbuf, sz);
free(buf, M_TEMP);
}
vrele(nd.ni_vp);
if (!cflag)
vrele(ndroot.ni_vp);
return error;
bad3:
vrele(ndroot.ni_vp);
bad2:
vrele(nd.ni_vp);
bad:
free(buf, M_TEMP);
return error;
}
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