NetBSD/sys/compat/common/compat_util.c

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/* $NetBSD: compat_util.c,v 1.14 1999/04/27 15:42:37 christos Exp $ */
1998-09-05 18:50:25 +04:00
/*-
* Copyright (c) 1994 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
1998-10-03 19:48:38 +04:00
* by Christos Zoulas and Frank van der Linden.
1998-09-05 18:50:25 +04:00
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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/exec.h>
#include <sys/ioctl.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/syslog.h>
#include <sys/mount.h>
#include <vm/vm_param.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.
*
* In case of success, emul_find returns 0:
* If sgp is provided, the path is in user space, and pbuf gets
* allocated in user space (in the stackgap). Otherwise the path
* is already in kernel space and a kernel buffer gets allocated
* and returned in pbuf, that must be freed by the user.
* In case of error, the error number is returned and *pbuf = path.
*/
int
emul_find(p, sgp, prefix, path, pbuf, cflag)
struct proc *p;
caddr_t *sgp; /* Pointer to stackgap memory */
const char *prefix;
const char *path;
const 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 provide an escape method, so that the user can
* always specify the real root. If the path is prefixed
* by /../ we kill the alternate search
*/
if (ptr[1] == '.' && ptr[2] == '.' && ptr[3] == '/') {
len -= 3;
(void)memcpy(buf, &ptr[3], len);
ptr = buf;
goto good;
}
/*
* 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 :-(
*/
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;
}
}
vrele(nd.ni_vp);
if (!cflag)
vrele(ndroot.ni_vp);
good:
if (sgp == NULL)
*pbuf = buf;
else {
sz = &ptr[len] - buf;
*pbuf = stackgap_alloc(sgp, sz + 1);
if ((error = copyout(buf, (void *)*pbuf, sz)) != 0) {
*pbuf = path;
return error;
}
free(buf, M_TEMP);
}
return 0;
bad3:
vrele(ndroot.ni_vp);
bad2:
vrele(nd.ni_vp);
bad:
free(buf, M_TEMP);
return error;
}
/*
* Translate one set of flags to another, based on the entries in
* the given table. If 'leftover' is specified, it is filled in
* with any flags which could not be translated.
*/
unsigned long
emul_flags_translate(const struct emul_flags_xtab *tab,
unsigned long in, unsigned long *leftover)
{
unsigned long out;
for (out = 0; tab->omask != 0; tab++) {
if ((in & tab->omask) == tab->oval) {
in &= ~tab->omask;
out |= tab->nval;
}
}
if (leftover != NULL)
*leftover = in;
return (out);
}
caddr_t
stackgap_init(e)
struct emul *e;
{
#define szsigcode ((caddr_t)(e->e_esigcode - e->e_sigcode))
return STACKGAPBASE;
#undef szsigcode
}
void *
stackgap_alloc(sgp, sz)
caddr_t *sgp;
size_t sz;
{
void *p = (void *) *sgp;
*sgp += ALIGN(sz);
return p;
}
void
compat_offseterr(vp, msg)
struct vnode *vp;
char *msg;
{
struct mount *mp;
mp = vp->v_mount;
log(LOG_ERR, "%s: dir offset too large on fs %s (mounted from %s)\n",
msg, mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname);
uprintf("%s: dir offset too large for emulated program\n", msg);
}