use temp directory as destination directory for copy command

[olamilekan000]

Change switches local tests from using $HOME/lima-hostname to a 
temporary directory to prevent conflicts with user-created files 
and permission errors when writing to it. 

Fixes #3162

[AkihiroSuda]

Suggested change

	tmpdir=$(mktemp -d /var/tmp/lima-test-templates.XXXXXX)
	tmpdir="$(mktemp -d /var/tmp/lima-test-templates.XXXXXX)"

[AkihiroSuda]

Also, why /var/tmp, not /tmp?

[AkihiroSuda]

On macOS, /var/tmp seems almost unused except the following files;

$ ls -la /var/tmp/
total 264
drwxrwxrwt   5 root           wheel     160  1 29 01:06 ./
drwxr-xr-x  34 root           wheel    1088  1 28 18:39 ../
-rw-r--r--   1 _windowserver  wheel  102400  1 28 18:39 cbrgbc_1.sqlite
-rw-r--r--   1 _windowserver  wheel   32768  1 28 18:39 cbrgbc_1.sqlite-shm
-rw-r--r--   1 _windowserver  wheel       0  1 28 18:39 cbrgbc_1.sqlite-wal

(Off-topic: what is "cbrgbc"? 🤔)

[olamilekan000]

Also, why /var/tmp, not /tmp?

I think any works since we just need a space where any user can create a file.

[olamilekan000]

On macOS, /var/tmp seems almost unused except the following files;

$ ls -la /var/tmp/
total 264
drwxrwxrwt   5 root           wheel     160  1 29 01:06 ./
drwxr-xr-x  34 root           wheel    1088  1 28 18:39 ../
-rw-r--r--   1 _windowserver  wheel  102400  1 28 18:39 cbrgbc_1.sqlite
-rw-r--r--   1 _windowserver  wheel   32768  1 28 18:39 cbrgbc_1.sqlite-shm
-rw-r--r--   1 _windowserver  wheel       0  1 28 18:39 cbrgbc_1.sqlite-wal

(Off-topic: what is "cbrgbc"? 🤔)

not sure what it is but it's definitely created by sqlite. It could be for macOS specific configs

[nirs]

The advantage of /var/tmp is that this is typically a standard file system on any platform. /tmp is is tmpfs on some Linux distros, which has special issues (direct I/O not supported, SEEK_HOLE/DATA very slow, etc). For our use case it should not matter.

Maybe we should just use $TMPDIR?

On macOS this is the safe user tmp directory used by most programs:

% echo $TMPDIR 
/var/folders/qs/_z10qgxn3gsfw8vmkr9b3s4w0000gn/T/

It can break if someone modify the env in a stupid way, but if they do they get what they deserve.

[AkihiroSuda]

Yes, $TMPDIR seems better

[jandubois]

On macOS, /var/tmp seems almost unused except the following files;

On macOS /tmp is also cleaned automatically: files not accessed for 3 days are deleted. The same is done for $TMPDIR. I don't think /var/tmp is cleaned automatically, but am not sure.

(Off-topic: what is "cbrgbc"? 🤔)

Comic Book Reader …? 🤣

[AkihiroSuda]

(Probably "cb" = "CoreBrightness", "rgbc" = "Red, Green, Blue, and Clear". The file is used by /System/Library/HIDPlugins/ColourSensorFilterPlugin.plugin/Contents/MacOS/ColourSensorFilterPlugin)

[nirs]

Based on the discussion, we should use here:

tmpdir="$(mktemp -d ${TMPDIR:-/tmp}/lima-test-templates.XXXXXX)"