Date: Sat, 23 Feb 2008 07:50:02 GMT From: Andriy Gapon <avg@icyb.net.ua> To: freebsd-emulation@FreeBSD.org Subject: Re: kern/73777: [linux] [patch] linux emulation: root dir special handling useless and harmful Message-ID: <200802230750.m1N7o2qv066693@freefall.freebsd.org>
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The following reply was made to PR kern/73777; it has been noted by GNATS.
From: Andriy Gapon <avg@icyb.net.ua>
To: bug-followup@FreeBSD.org
Cc:
Subject: Re: kern/73777: [linux] [patch] linux emulation: root dir special
handling useless and harmful
Date: Sat, 23 Feb 2008 09:46:53 +0200
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Well, I think that the issue described in this PR still holds.
On the other hand, I now think that some people might still prefer
current behavior over what I suggest. There could be some POLA concerns too.
Another concern is that now the code is common to all emulation, so it's
not linux specific anymore.
In any case, I am attaching a patch that I currently use.
--
Andriy Gapon
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Content-Type: text/x-patch;
name="rootdir-6.patch"
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Content-Disposition: inline;
filename="rootdir-6.patch"
--- sys/kern/vfs_lookup.c.orig Fri May 12 16:03:41 2006
+++ sys/kern/vfs_lookup.c Fri May 12 16:09:31 2006
@@ -955,7 +955,7 @@
kern_alternate_path(struct thread *td, const char *prefix, char *path,
enum uio_seg pathseg, char **pathbuf, int create)
{
- struct nameidata nd, ndroot;
+ struct nameidata nd;
char *ptr, *buf, *cp;
size_t len, sz;
int error;
@@ -1014,28 +1014,6 @@
error = namei(&nd);
if (error != 0)
goto keeporig;
-
- /*
- * We now compare the vnode of the prefix 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 | MPSAFE, UIO_SYSSPACE, prefix,
- td);
-
- /* We shouldn't ever get an error from this namei(). */
- error = namei(&ndroot);
- if (error == 0) {
- if (nd.ni_vp == ndroot.ni_vp)
- error = ENOENT;
-
- NDFREE(&ndroot, NDF_ONLY_PNBUF);
- vrele(ndroot.ni_vp);
- VFS_UNLOCK_GIANT(NDHASGIANT(&ndroot));
- }
}
NDFREE(&nd, NDF_ONLY_PNBUF);
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