On Tue, Aug 11, 2020 at 04:22:19PM +0200, Miklos Szeredi wrote: > On Tue, Aug 11, 2020 at 4:08 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > > On Tue, Aug 11, 2020 at 03:54:19PM +0200, Miklos Szeredi wrote: > > > On Wed, Aug 05, 2020 at 10:24:23AM +0200, Miklos Szeredi wrote: > > > > On Tue, Aug 4, 2020 at 4:36 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > > > > > > > > I think we already lost that with the xattr API, that should have been > > > > > done in a way that fits this philosophy. But given that we have "/" > > > > > as the only special purpose char in filenames, and even repetitions > > > > > are allowed, it's hard to think of a good way to do that. Pity. > > > > > > > > One way this could be solved is to allow opting into an alternative > > > > path resolution mode. > > > > > > > > E.g. > > > > openat(AT_FDCWD, "foo/bar//mnt/info", O_RDONLY | O_ALT); > > > > > > Proof of concept patch and test program below. > > > > > > Opted for triple slash in the hope that just maybe we could add a global > > > /proc/sys/fs/resolve_alt knob to optionally turn on alternative (non-POSIX) path > > > resolution without breaking too many things. Will try that later... > > > > > > Comments? > > > > Hell, NO. This is unspeakably tasteless. And full of lovely corner cases wrt > > symlink bodies, etc. > > It's disabled inside symlink body resolution. > > Rules are simple: > > - strip off trailing part after first instance of /// > - perform path lookup as normal > - resolve meta path after /// on result of normal lookup ... and interpolation of relative symlink body into the pathname does change behaviour now, *including* the cases when said symlink body does not contain that triple-X^Hslash garbage. Wonderful...
