Re: Issue with permissions and case-insensitive globbing

[Devin Hussey <husseydevin@xxxxxxxxx>]

Actually, I think I found the fix. We can simply continue recursing
(skipping the readdir() loop) if we hit EACCES. EACCES seems to have
lower priority than ENOENT/ENOTDIR, so it won't end up in an infinite
loop or any of that.

I have a patch to change this, although it has only gone through
preliminary testing.

On 1/12/21, Mikael Magnusson <mikachu@xxxxxxxxx> wrote:
> On 1/12/21, Devin Hussey <husseydevin@xxxxxxxxx> wrote:
>> Case insensitive globbing will not work at all if any of the parent
>> directories of the target folder are inaccessible.
>>
>> This bug makes zsh very unstable on Termux (a Linux environment for
>> Android), as scripts which use "~/..." will immediately show no
>> results.
>>
>> Android's directory structure makes it so apps can only access their
>> /data/data subfolder, blocking access to /data/data itself (it will
>> return EACCES).
>>
>> Termux's $HOME is /data/data/com.termux/files/home.
>>
>> The simplified folder setup is this:
>>
>> root    root    0700 /
>> root    root    0700 /data
>> root    root    0700 /data/data
>> termux termux 0700 /data/data/com.termux
>>
>> A (possible) fix for this issue would be to start in the "base"
>> directory before any opendir() calls instead of starting from the root
>> directory, and checking for errno.
>>
>> See:
>>
>>  - https://github.com/sorin-ionescu/prezto/issues/1560
>> - https://github.com/termux/termux-packages/issues/1894
>
> I can only reproduce this with absolute paths, which will obviously
> not work (there's no way it ever could, as the kernel will not let you
> open the directory). It seems to be completely independent of case
> sensitivity as well. Using a relative path should work fine.
>
> To expound a bit,
> % mkdir inaccessible; cd inaccessible
> % mkdir a; cd a
> % chmod 000 .. # make inaccessible inaccessible
> % touch a b c; echo *
> a b c
> % echo $PWD/*
> zsh: no matches found: /tmp/inaccessible/a/*
>
> (you will get the same result in any other shell (some may echo the
> path with the * unexpanded)).
>
> --
> Mikael Magnusson
>