Permission error when packing to squashfs file on Linux

[Kirill888]

Checklist

• [X] I added a descriptive title
• [X] I searched open reports and couldn't find a duplicate

What happened?

While running command like this

conda pack --format=squashfs -n test-env 

Things break when copying activate script over into temp location, this happens when

1. Conda is installed by root
2. Temp folder is on the same disk as conda

When creating temp copy of the environment squashfs plugin prefers to use hard-links when copying files on Linux

https://github.com/conda/conda-pack/blob/fcba5e0d21a5c0926e4f5c97c1d6d638ddaa8ca0/conda_pack/formats.py#L439-L443

but this doesn't work when source file is not owned by the user running conda pack. This is the case when conda-pack is installed by root in base environment, while user running the packing is not root

https://github.com/conda/conda-pack/blob/fcba5e0d21a5c0926e4f5c97c1d6d638ddaa8ca0/conda_pack/formats.py#L458

Traceback (most recent call last):
  File "/opt/conda/lib/python3.10/site-packages/conda_pack/cli.py", line 157, in main
    pack(name=args.name,
  File "/opt/conda/lib/python3.10/site-packages/conda_pack/core.py", line 542, in pack
    return env.pack(output=output, format=format,
  File "/opt/conda/lib/python3.10/site-packages/conda_pack/core.py", line 386, in pack
    packer.finish()
  File "/opt/conda/lib/python3.10/site-packages/conda_pack/core.py", line 1142, in finish
    self.archive.add(source, target)
  File "/opt/conda/lib/python3.10/site-packages/conda_pack/formats.py", line 247, in add
    self._add(source, target)
  File "/opt/conda/lib/python3.10/site-packages/conda_pack/formats.py", line 487, in _add
    copy_func(source, target_abspath)
PermissionError: [Errno 1] Operation not permitted: '/opt/conda/lib/python3.10/site-packages/conda_pack/scripts/posix/activate' -> '/tmp/tmp9x4imir_/bin/activate'

in the above copy_func is partial(os.link, follow_symlinks=False). os.link should be used only when source and destination share:

1. same device
2. same owner (st_uid)

Conda Info

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Conda Config

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Conda list

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Additional Context

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