[Toybox] [PATCH] Fix truncate.test for macOS.

[Rob Landley]

On 7/25/22 11:48, enh wrote:
>     >     Is there a portable way to determine filesystem type, though? df .
>     doesn't say,
>     >     I have to look in /proc/mounts and I doubt mac has that?
>     >
>     >     $ grep -w "^$(df . | tail -n 1 | toybox cut -DF 1)" /proc/mounts | toybox
>     >     cut -DF 3
>     >
>     >     (I THINK that if the device has a space in it df will output the escaped
>     >     version, which should match for grep... But again: Linux.)
>     >
>     > on the mac it looks like mount is your best bet:
>     >
>     > ~$ mount
>     > /dev/disk3s1s1 on / (apfs, sealed, local, read-only, journaled)
>     > ...
>     >
>     > but maybe just "it's a mac, it's probably using apple's default fs" is
>     sufficient?
> 
>     Hmmm...
> 
>     sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
> 
>     Word 4 vs word 5. I guess I could check for "type" and advance, else strip off
>     the starting "("... Of course now that I've sat down to implement an
>     is_filesystem shell function, I'm trying to figure out what the right question
>     to ask here, and checking for a single filesystem type is basically is_mkroot,
>     while a whitelist of known filesystem types is bound to accordion out
>     unpleasantly while STILL breaking for people...
> 
>     Blah. This is a design issue. What behavior do we WANT here?
> 
>     Query: what filesystem A) are you running this under on the android test system,
>     B) is available as "scratch space" to an application on an android phone?
> 
> depends on the device. there are some restrictions (and actually the writeable
> space might be (a) more restricted and (b) less likely something that the OEMs
> change) but since the toybox tests aren't (yet) in CTS, "works on Google's CI"
> is good enough for now. we can worry about "how do these tests work on every
> device configuration that it's possible to ship?" if/when that's an actual problem.

What are CTS and CI?

I am actively working on making it an actual problem. (Yeah yeah, horrible goos
causing problems on purpose.)

Rob