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1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
183 lines
4.8 KiB
C
183 lines
4.8 KiB
C
/*
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* Copyright (c) 1994 Christos Zoulas
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* Copyright (c) 1995 Frank van der Linden
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* Copyright (c) 1995 Scott Bartram
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: svr4_util.c,v 1.5 1995/01/22 23:44:50 christos Exp
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/namei.h>
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#include <sys/proc.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/filedesc.h>
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#include <sys/ioctl.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/vnode.h>
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#include <i386/linux/linux_util.h>
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const char linux_emul_path[] = "/compat/linux";
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/*
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* Search an alternate path before passing pathname arguments on
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* to system calls. Useful for keeping a seperate 'emulation tree'.
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*
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* If cflag is set, we check if an attempt can be made to create
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* the named file, i.e. we check if the directory it should
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* be in exists.
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*/
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int
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linux_emul_find(p, sgp, prefix, path, pbuf, cflag)
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struct proc *p;
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caddr_t *sgp; /* Pointer to stackgap memory */
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const char *prefix;
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char *path;
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char **pbuf;
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int cflag;
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{
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struct nameidata nd;
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struct nameidata ndroot;
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struct vattr vat;
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struct vattr vatroot;
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int error;
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char *ptr, *buf, *cp;
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size_t sz, len;
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buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
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*pbuf = path;
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for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++)
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continue;
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sz = MAXPATHLEN - (ptr - buf);
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/*
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* If sgp is not given then the path is already in kernel space
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*/
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if (sgp == NULL)
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error = copystr(path, ptr, sz, &len);
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else
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error = copyinstr(path, ptr, sz, &len);
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if (error) {
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free(buf, M_TEMP);
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return error;
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}
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if (*ptr != '/') {
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free(buf, M_TEMP);
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return EINVAL;
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}
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/*
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* We know that there is a / somewhere in this pathname.
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* Search backwards for it, to find the file's parent dir
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* to see if it exists in the alternate tree. If it does,
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* and we want to create a file (cflag is set). We don't
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* need to worry about the root comparison in this case.
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*/
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if (cflag) {
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for (cp = &ptr[len] - 1; *cp != '/'; cp--);
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*cp = '\0';
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
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if ((error = namei(&nd)) != 0) {
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free(buf, M_TEMP);
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return error;
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}
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*cp = '/';
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}
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else {
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NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, p);
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if ((error = namei(&nd)) != 0) {
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free(buf, M_TEMP);
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return error;
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}
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/*
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* We now compare the vnode of the linux_root to the one
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* vnode asked. If they resolve to be the same, then we
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* ignore the match so that the real root gets used.
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* This avoids the problem of traversing "../.." to find the
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* root directory and never finding it, because "/" resolves
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* to the emulation root directory. This is expensive :-(
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*/
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NDINIT(&ndroot, LOOKUP, FOLLOW, UIO_SYSSPACE, linux_emul_path,
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p);
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if ((error = namei(&ndroot)) != 0) {
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/* Cannot happen! */
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free(buf, M_TEMP);
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vrele(nd.ni_vp);
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return error;
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}
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if ((error = VOP_GETATTR(nd.ni_vp, &vat, p->p_ucred, p)) != 0) {
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goto bad;
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}
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if ((error = VOP_GETATTR(ndroot.ni_vp, &vatroot, p->p_ucred, p))
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!= 0) {
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goto bad;
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}
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if (vat.va_fsid == vatroot.va_fsid &&
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vat.va_fileid == vatroot.va_fileid) {
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error = ENOENT;
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goto bad;
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}
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}
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if (sgp == NULL)
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*pbuf = buf;
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else {
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sz = &ptr[len] - buf;
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*pbuf = stackgap_alloc(sgp, sz + 1);
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error = copyout(buf, *pbuf, sz);
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free(buf, M_TEMP);
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}
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vrele(nd.ni_vp);
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if (!cflag)
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vrele(ndroot.ni_vp);
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return error;
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bad:
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vrele(ndroot.ni_vp);
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vrele(nd.ni_vp);
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free(buf, M_TEMP);
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return error;
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}
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