Problem with test -r

[Dominique Martinet]

David Laight wrote on Mon, Feb 13, 2023 at 09:00:47AM +0000:
> From: Vladimír Macek
> > I'd like to report what seems to be a bug in the busybox's test command. I
> > use the official alpine:3 docker container.
> > 
> > The test -r does not return true even when the file is indeed readable
> > (testing by head command). Yes, the file has an unusual set of permissions,
> > but that does not restrict it from reading. Here's the output of the
> > interactive container shell session:
> > 
> > dd72078df6d2:/task/output/files$ ls -lad . .. cnb_rate_eur_czk.csv
> > drwxrwx---    2 setup    project        4096 Feb 11 18:33 .
> > drwxr-x---    5 setup    project        4096 Feb 11 18:33 ..
> > -rw-r--r--    1 task     project       20512 Feb 11 18:33 cnb_rate_eur_czk.csv
> 
> By the look of it the problem is that 'test -r' requires
> directory search access - so why not just say that.

It has x on directory (both as user and group), so what's the problem?

I also cannot reproduce with the same busybox version he reports using
anyway, and busybox' test has not changed from 1.32 to 1.35 so I'd say
"strace or it didn't happen".

Could be a weird side effect of what I assume to be a volume mount for
/task, how the directory was made was not specified.


b4adb3ccf49f:/task/output/files$ id
uid=2001(setup) gid=2000(project) groups=2000(project),2000(project)
b4adb3ccf49f:/task/output/files$ ls -lad . .. cnb_rate_eur_czk.csv 
drwxr-xr-x    1 root     root            40 Feb 13 11:08 .
drwxrwx---    1 setup    project         10 Feb 13 11:07 ..
-rw-r--r--    1 task     project          4 Feb 13 11:01 cnb_rate_eur_czk.csv
b4adb3ccf49f:/task/output/files$ busybox | head -n 1
BusyBox v1.35.0 (2022-11-19 10:13:10 UTC) multi-call binary.
b4adb3ccf49f:/task/output/files$ [ -r cnb_rate_eur_czk.csv ] && echo READABLE
READABLE
b4adb3ccf49f:/task/output/files$ [[ -r cnb_rate_eur_czk.csv ]] && echo READABLE
READABLE
b4adb3ccf49f:/task/output/files$ /usr/bin/[ -r cnb_rate_eur_czk.csv ] && echo READABLE
READABLE
b4adb3ccf49f:/task/output/files$ cat /etc/alpine-release 
3.17.2


-- 
Dominique