Re: Remote temporary directory

[Michael Albinus]

Stefan Monnier <address@hidden> writes:

> Maybe a new `make-nearby-temp-file` would work, where Emacs would try to
> create the temp file "as close as possible" to some target directory.
>
> This could also be used for things like "save into a temp file and then
> rename that file to the actual destination".

Will do.

> This said, there are some non-trivial security issues at stake here:
> make-temp-file should usually only be used in directories which are
> either only writable by "trusted" users (i.e. only by the current user),
> or which have the magical "sticky" bit set.  So using just any writable
> "nearby" directory is generally unsafe.

I agree. But `make-temp-file' does not check:

(let ((temporary-file-directory "~/")) (make-temp-file "tmp"))
=> "/home/albinus/tmp17866D3i"

It will be even harder to fulfill this in the remote case. Shall we add
an optional argument SAVE-DIR-ONLY to `make-temp-file' /
`make-nearby-temp-file'?  If non-nil, the checks above are performed.

Furthermore, there are file name handlers which do not know of a
temporary directory. Think about "/davs:" or "/gdrive:" etc. On those
remote locations, the function `temporary-file-directory' will return
the current remote directory, and `make-nearby-temp-file' will create
the temp file here.

>         Stefan

Best regards, Michael.