freebsd-dev/sys/compat/linux/linux_util.c
Don Lewis ff5f695e78 VOP_GETATTR() wants the vnode passed to it to be locked. Instead
of adding the code to lock and unlock the vnodes and taking care
to avoid deadlock, simplify linux_emul_convpath() by comparing the
vnode pointers directly instead of comparing their va_fsid and
va_fileid attributes.  This allows the removal of the calls to
VOP_GETATTR().
2004-01-14 22:38:03 +00:00

209 lines
5.3 KiB
C

/*
* Copyright (c) 1994 Christos Zoulas
* Copyright (c) 1995 Frank van der Linden
* Copyright (c) 1995 Scott Bartram
* 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.
*
* from: svr4_util.c,v 1.5 1995/01/22 23:44:50 christos Exp
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <machine/stdarg.h>
#include <compat/linux/linux_util.h>
const char linux_emul_path[] = "/compat/linux";
/*
* 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
linux_emul_find(td, sgp, path, pbuf, cflag)
struct thread *td;
caddr_t *sgp; /* Pointer to stackgap memory */
char *path;
char **pbuf;
int cflag;
{
char *newpath;
size_t sz;
int error;
error = linux_emul_convpath(td, path, (sgp == NULL) ? UIO_SYSSPACE :
UIO_USERSPACE, &newpath, cflag);
if (newpath == NULL)
return (error);
if (sgp == NULL) {
*pbuf = newpath;
return (error);
}
sz = strlen(newpath);
*pbuf = stackgap_alloc(sgp, sz + 1);
if (*pbuf != NULL)
error = copyout(newpath, *pbuf, sz + 1);
else
error = ENAMETOOLONG;
free(newpath, M_TEMP);
return (error);
}
int
linux_emul_convpath(td, path, pathseg, pbuf, cflag)
struct thread *td;
char *path;
enum uio_seg pathseg;
char **pbuf;
int cflag;
{
struct nameidata nd;
struct nameidata ndroot;
int error;
const char *prefix;
char *ptr, *buf, *cp;
size_t len, sz;
buf = (char *) malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
*pbuf = buf;
prefix = linux_emul_path;
for (ptr = buf; (*ptr = *prefix) != '\0'; ptr++, prefix++)
continue;
sz = MAXPATHLEN - (ptr - buf);
if (pathseg == UIO_SYSSPACE)
error = copystr(path, ptr, sz, &len);
else
error = copyinstr(path, ptr, sz, &len);
if (error) {
*pbuf = NULL;
free(buf, M_TEMP);
return error;
}
if (*ptr != '/') {
error = EINVAL;
goto keeporig;
}
/*
* 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, td);
error = namei(&nd);
*cp = '/';
if (error != 0)
goto keeporig;
}
else {
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, buf, td);
if ((error = namei(&nd)) != 0)
goto keeporig;
/*
* We now compare the vnode of the linux_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, linux_emul_path,
td);
if ((error = namei(&ndroot)) != 0) {
/* Cannot happen! */
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
goto keeporig;
}
if (nd.ni_vp == ndroot.ni_vp) {
error = ENOENT;
goto bad;
}
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
if (!cflag) {
NDFREE(&ndroot, NDF_ONLY_PNBUF);
vrele(ndroot.ni_vp);
}
return error;
bad:
NDFREE(&ndroot, NDF_ONLY_PNBUF);
vrele(ndroot.ni_vp);
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
keeporig:
/* Keep the original path; copy it back to the start of the buffer. */
bcopy(ptr, buf, len);
return error;
}
void
linux_msg(const struct thread *td, const char *fmt, ...)
{
va_list ap;
struct proc *p;
p = td->td_proc;
printf("linux: pid %d (%s): ", (int)p->p_pid, p->p_comm);
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
printf("\n");
}