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Re: tramp ControlMaster options
From: |
Yuri D'Elia |
Subject: |
Re: tramp ControlMaster options |
Date: |
Mon, 20 Jul 2015 22:41:02 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.0 |
On 20/07/15 20:43, Michael Albinus wrote:
> Likely you mean `tramp-ssh-controlmaster-options'. This is a variable,
> and it will be computed only when it is needed. No Tramp ssh connection,
> no probe of ssh for this.
I hope I understand how defcustom works(?).
In emacs 24.5.1, I see this at line 310 of tramp.el:
(defcustom tramp-ssh-controlmaster-options
...
whose standard value is computed by calling ssh a few times.
I don't know what the ;;;###tramp-autoload cookie does though, but no
miracles I assume?
Just to confirm, this is the output of "strace -f -e trace=process"
after a (require 'tramp):
[pid 2189] vfork(Process 2255 attached
<unfinished ...>
[pid 2255] execve("/usr/bin/ssh", ["/usr/bin/ssh", "-o",
"ControlMaster"], [/* 73 vars */] <unfinished ...>
[pid 2189] <... vfork resumed> ) = 2255
[pid 2255] <... execve resumed> ) = 0
[pid 2255] arch_prctl(ARCH_SET_FS, 0x7fcdde4cd800) = 0
...
>> Any reason why we cannot use `ssh -o BatchMode=yes [various flags]
>> 0.0.0.0' instead of using a domain name? This would greatly reduce the
>> issue.
>
> The function (!) `tramp-ssh-controlmaster-options' uses "localhost" for
> test. This shall avoid DNS requests.
Still connects to a valid host, which might have a daemon running (in
fact, I have one on localhost for debugging).
If there's no reason to connect to something, call 0.0.0.0.
I love that tramp detects ControlMaster support in ssh, but calling
external processes on load, if really needed, should /really/ be quick.
- package.el: what does package "Checking ... " actually do?, Yuri D'Elia, 2015/07/17
- Re: package.el: what does package "Checking ... " actually do?, Artur Malabarba, 2015/07/17
- Re: package.el: what does package "Checking ... " actually do?, Yuri D'Elia, 2015/07/18
- tramp ControlMaster options (was: Re: package.el: what does package "Checking ... " actually do?), Yuri D'Elia, 2015/07/18
- Message not available
- Re: tramp ControlMaster options, Michael Albinus, 2015/07/20
- Re: tramp ControlMaster options, Thierry Volpiatto, 2015/07/20
- Re: tramp ControlMaster options, Yuri D'Elia, 2015/07/20
- Re: tramp ControlMaster options, Michael Albinus, 2015/07/20
- Re: tramp ControlMaster options,
Yuri D'Elia <=
- Re: tramp ControlMaster options, Thierry Volpiatto, 2015/07/21
- Re: tramp ControlMaster options, Michael Albinus, 2015/07/21
- Re: tramp ControlMaster options, Thierry Volpiatto, 2015/07/21
- Re: tramp ControlMaster options, Yuri D'Elia, 2015/07/21
- Re: tramp ControlMaster options, Michael Albinus, 2015/07/22