Re: tramp (2.7.0-pre nil/nil); Can't connect to server anymore

[Michael Albinus]

"Kirill A. Korinsky" <kirill@korins.ky> writes:

> Hi Michael,

Hi Kirill,

> I've achieved that on OpenBSD where I've switched /tmp to ramdisk.
>
> It uses so-called mfs driver which inherits permissions from the
> mountpoint.

That sounds a little bit too expansive for my test environment.

I've tried to reproduce the problem with setting the
remote-temporary-file-directory to /home/admin/tmp w/o write
permissions. Then I've started

--8<---------------cut here---------------start------------->8---
emacs --eval '(add-to-list (quote tramp-connection-properties) (list nil 
"tmpdir" "/home/admin/tmp"))' /ssh:ubuntu-2204:
--8<---------------cut here---------------end--------------->8---

Which tells Tramp to use "/home/admin/tmp" instead of "/tmp" on the
remote side. Tramp did connect w/o problem, meaning that it didn't try
to write to "/home/admin/tmp". When copying a local file to the remote
host in Emacs, there is the error

--8<---------------cut here---------------start------------->8---
Copying /home/albinus/123 to /ssh:ubuntu-2204:/home/admin/123...failed
File error: Directory /ssh:ubuntu-2204:/home/admin/tmp not accessible
--8<---------------cut here---------------end--------------->8---

This is expected, because Tramp needs to create a temporary file for
this, which doesn't work. And the check inside Tramp works.

That indicates, that the error in your case, writing to an improper /tmp
directory, isn't caused by Tramp directly, but rather by an external
program Tramp runs on the remote side behind the scenes. Could you
please verify this? Remove write permissions from the remote /tmp
directory, and start Emacs like this:

--8<---------------cut here---------------start------------->8---
# emacs -l tramp --eval '(setq tramp-verbose 10)' /ssh:some.host:
--8<---------------cut here---------------end--------------->8---

The error should appear, and there should be a Tramp debug buffer. This
might tell us more. If you fear to uncover sensible information with the
debug buffer, send it directly to me.

Best regards, Michael.