Le Sat, May 27, 2023 at 11:56:16PM +0700, Robert Elz a écrit :
> I'm dual-posting this to tech-kern and tech-userlevel, as while it is
> a userlevel issue, it could have kernel implications. Please respect
> the Reply-To and send replies only to tech-userlevel
>
> You may have noticed that a recent change (mine) to the pathadj()
> function (which converts an abritrary path name to its canonical form).
> That function is not permitted to fail, but could. Now instead of
> failing, and returning (potential) nonsense, it exits if it cannot
> do what it is required to do (usually it can). In practice this
> affects nothing real.
>
> However, it affects some uses of rump - which sets up a "block device"
> in a way that its name cannot be canonicalised. It was relying upon
> the way that pathadj() happens to work (based upon how realpath(3) works)
> to make things function - pathadj() was issuing an error message, which
> some rump using ATF tests were simply ignoring (deliberately).
>
> Yesterday, I was trying to find a way to make this all work - unsuccessfully.
>
Since pathadj() was just sugar, calling realpath(3) (without really
testing the return) and emitting some messages, in a special case can
you simply "flatten" the thing i.e. replace the call to pathadj() by a
call to realpath(3)?
And then, there should be a code similar to what is done in
src/sbin/mount/mount.c: if canonical_path is NULL, try what the user
passed:
219,224
/*
* Create a canonical version of the device or mount path
* passed to us. It's ok for this to fail. It's also ok
* for the result to be exactly the same as the original.
*/
canonical_path = realpath(*argv, canonical_path_buf);
227,238
/*
* Try looking up the canonical path first,
* then try exactly what the user entered.
*/
if ((canonical_path == NULL ||
(mntbuf = getmntpt(canonical_path)) == NULL) &&
(mntbuf = getmntpt(*argv)) == NULL) {
out:
errx(EXIT_FAILURE,
"Unknown special file or file system `%s'",
*argv);
}
>From a superficial knowledge, it seems to me that, eventually,
the __mount50() syscall has to be called with a canonical path,
since the syscall does no acrobatics with the path (and shall not be
passed garbage).
FWIW
--
Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
http://www.kergis.com/
http://kertex.kergis.com/
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