[Bug 687535] Re: upstart loses track of ssh daemon after reload ssh

[Scott James Remnant (Canonical)]

Ah, then ssh already had that race.

In which case -D seems like a good choice

On Mon, Dec 13, 2010 at 11:05 PM, Clint Byrum <clint at fewbar.com> wrote:

> The code looks something like this:
>
> [ option parsing, config check, etc ]
> sshd.c, line 1744: daemon()
> [ reinit logs, start random number generator, chdir to /, ignore SIGPIPE ]
> sshd.c, line 1774: server_listen() -- socket(), bind(), listen(), etc.
>
> So, there's already a race between considering it started (at the fork
> caused by daemon()), and sshd listening, right? Its just that now we're
> considering it started before the config check and option parsing, so
> that does give any dependent upstart jobs a bigger head start than they
> already had.
>
> --
> You received this bug notification because you are a member of Upstart
> Developers, which is subscribed to upstart .
> https://bugs.launchpad.net/bugs/687535
>
> Title:
>  upstart loses track of ssh daemon after reload ssh
>
> Status in Upstart:
>  New
> Status in “openssh” package in Ubuntu:
>  Confirmed
> Status in “openssh” source package in Lucid:
>  Confirmed
> Status in “openssh” source package in Maverick:
>  Confirmed
>
> Bug description:
>  When sshd gets a signal 1 for reload, it forks a new process and ditches
> the old. This causes upstart to believe that ssh has crashed, and loses
> track of it. A second reload (or any other initctl operation on ssh) will
> thus say:
>
> reload: Unknown instance:
>
> There would be 2 ways to fix this:
> 1.  Don't have ssh fork on relod, but keep the same pid
> 2. Use a different mechanism in upstart to keep track of ssh. Maybe a pid
> file? Just tracking children of the exited ssh won't work, or it might
> accidentally track a particular session rather than the master, if somebody
> just happens to log in close to reload time.
>
>
> # lsb_release -rd
> Description:    Ubuntu 10.04.1 LTS
> Release:        10.04
>
> # dpkg -l openssh-server | cat
> Desired=Unknown/Install/Remove/Purge/Hold
> |
> Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend
> |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
> ||/ Name                                        Version
>                                Description
>
> +++-===========================================-==========================================================-=================================================================
> ii  openssh-server                              1:5.3p1-3ubuntu4
>                                 secure shell (SSH) server, for secure access
> from remote machines
>
> # dpkg -l upstart
> Desired=Unknown/Install/Remove/Purge/Hold
> |
> Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend
> |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
> ||/ Name           Version        Description
>
> +++-==============-==============-============================================
> ii  upstart        0.6.5-7        event-based init daemon
>
>
>

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https://bugs.launchpad.net/bugs/687535

Title:
  upstart loses track of ssh daemon after reload ssh