Mosh Detached session message

[sn00pster]

mosh-server has the ability to display a message telling you of any detached sessions that are connected to the server.

This support is based on utmp and libutempter. The current build of the mosh server does not link against libutempter, therefore the functionality is not available.

I have done some very hacky exploratory work, basically fudging into the build a Makefile for utempter which requires a lot of interaction while building to get it to use and link against utempter.

However, the message is still not displayed, so there is something else at fault here. I will try to discover what it is, but I know nothing about the correct way of getting utempter to automatically build and use a configure script, so I cannot share my work on this as it requires me to manually edit files during building and after failures in order to get the library built.

Any pointers on how I can get libutempter to download and configure/build properly would be helpful and would certainly advance figuring out what is going on.

[m4tt075]

I'll be happy to help, if you are willing to do all the testing. Just PR your WIP and we'll take it from there... ;-)

[sn00pster]

Let me try and figure something out, I can’t do a PR on the hacky bit as I’m fudging stuff inside the work-x64 folder as it builds.... I can do a PR on the libutempter “module” under cross and the additional dependency that mosh now has on it.

libutempter does not use a configure script, it’s just a Makefile, I used autoconf to generate a configure script and then once it started building I then replaced the generated Makefile with a modified version of the original makefile from the source package so that the libraries get written to the right place so that when mosh builds its configure script picks up that libutempter is available.....told you it was a hack! Lol

I’m an embedded software engineer by trade and my only PC coding these days is limited to Qt, so I never get involved with makefiles which is why i’ve Struggled to this point.

[m4tt075]

To get you started with our build system:

• You will need to create a cross-package for utempter in /cross/utempter. Then, you will have to add that as a dependency in the cross/mosh/Makefile , make it compile and put the libraries in the right place.
• Start creating the cross/utempter package first
• You can copy the Makefile from /cross/mosh for instance to get you started
• If there is no configure script, you can override configuration by adding CONFIGURE_TARGET = nop in the Makefile and the step will be skipped. I don't think autoconf will be needed.
• Pathes can be a bit tricky. Is there an option to define an INSTALL_PREFIX?

P.S.: I'm working in marketing these days. If I can do it, you can... :-)

[sn00pster]

Thanks! I spent ages looking for how to disable configure!! I’ve done cross/utempter Added the dependency in cross/mosh/Makefile Will doublecheck the Makefile for installpath. Thanks, this has been very helpful. I can see a way through way this with these hints! Just double checked the Makefile, no it doesn’t use INSTALL_PATH, they’re hard coded variables, just these three that I changed, that was the only patch to the Makefile. libdir = /usr/lib libexecdir = /usr/lib includedir = /usr/include

[m4tt075]

Right. OK, you'll have to patch them out. I'd add a patch replacing usr by something like an %install_prefix% placeholder. That patch will be applied automatically during the build process. Then, you should be able to add some post_patch_target to the Makefile replacing that placeholder by the $(STAGING_INSTALL_PREFIX) variable. This is, where all the dependencies are staged and where mosh should be looking. You can refer to /cross/tvheadend for an examplatory post_patch_target implementation.

Eventually, you will also need some other stuff, i.e. PLIST and digests files. You'll find the background here: https://github.com/SynoCommunity/spksrc/wiki/Developers-HOW-TO

[sn00pster]

Perfect, I’ve been awake for 40 odd hours now so will take this up again tomorrow.  I’ve already done the PLIST and digest file, the patch should be easy as I’ve seen examples in the cross folder and they’re minor modifications. Thank you very much for your help.

…

On 16 Jan 2019, 21:16 +0000, m4tt075 ***@***.***>, wrote: Right. OK, you'll have to patch them out. I'd add a patch replacing usr by something like an %install_prefix% placeholder. That patch will be applied automatically during the build process. Then, you should be able to add some post_patch_target to the Makefile replacing that placeholder by the $(STAGING_INSTALL_PREFIX) variable. This is, where all the dependencies are staged and where mosh should be looking. You can refer to /cross/tvheadend far an examplatory post_patch_target implementation. Eventually, you will also need some other stuff, i.e. PLIST and digests files. You'll find the background here: https://github.com/SynoCommunity/spksrc/wiki/Developers-HOW-TO — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[sn00pster]

One other quick question, how do I clean say my libutempter build tree so that I can rebuild it from scratch? I don’t want to clean the whole working tree as that would obviously mean rebuilding everything, I just want to be able to clean certain bits so that I can test as I go along.

[m4tt075]

If you cd into the overarching spk/working-<arch>-<fwvers> directory and run ls -latr, you'll see cookie files, like .copy.done, for all the individual build steps and recursions into cross packages, that have been completed. You can remove the cookie files of the build steps you want to repeat.

[sn00pster]

Awesome @m4tt075

Using the information you've provided here, I now have the cross/libutempter "module" fully working patches, build etc.

Should I put together a PR here for the WIP, although it's not currently working (i.e the message about detached sessions is not appearing), mosh is seeing the library during configuration and building the binary with the appropriate support - I now need to do some debugging to find out why it's not displaying.

Couldn't have done this without your excellent help!

One step closer.

By the way, I couldn't get the "clean" to work, I deleted the cookies and also the libutempter build folder, but when I did a make again it just didn't do anything and just told me nothing to be done, any further suggestions?

[m4tt075]

Glad to hear it went so well and happy to help. You are advancing this project and we appreciate anybody willing to contribute!

On your question: Yes, it might not work if you cut out intermediate build steps. To make it work, usually you have to remove all the build steps and sub-directories created by a cross package. It might also be necessary to remove all subsequent build steps if there are interdependencies. You'd certainly have to remove those steps consolidating and creating the final package itself as well. I admit it can be tricky...

[dulitz]

Thanks a million y'all. Mosh with detached sessions would be completely amazing.

[sn00pster]

OK, so appointments finished early today and I decided to torture myself by debugging this on my iPad over a mosh connection to my server.

I now have libutempter working. It requires a few more patches and I will try to clean up the makefile as well as there's a load of stuff in there which was commented on above that isnt actually needed.

Upshot is that mosh connections now show any detached sessions!

Will try to sort this out tomorrow when I'm back at a proper keyboard, this was hard work on a touchscreen and sftping files about!

[ymartin59]

For information - it will have almost no impact technically - I have decided to move mosh out of "synocli-net" and create a dedicated package for it alone - because of its dependency volumes and requirement for Perl package installation.

[sn00pster]

@ymartin59 good call, I think it makes sense to be a separate package anyway, it's such a great tool. Been very handy today when ssh would have kicked me out quite a number of times.

Glad to have contributed something as minor as the detached session reporting.

[iFredOS]

How is it possible to download the separated Mosh package? I'm looking for Mosh for DSM for a few days and found this discussion.

[chickenandpork]

I think it may show on https://synocommunity.com/packages when available but for now you might need to get it by installing synocli ( https://synocommunity.com/package/synocli-net ) .. probably better to put the package repos url into your NAS and pull packages through the standard interface though (look for “Easy Install” on https://synocommunity.com/ )

…

On Feb 20, 2019, at 12:54, iFredOS ***@***.***> wrote: How is it possible to download the separated Mosh package? I'm looking for Mosh for DSM for a few days and found this discussion. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[sn00pster]

Bear in mind this conversation, it doesn’t currently build against libutempter so it’s posdible to create a lot of detached sessions and not realise.

[iFredOS]

Bear in mind this conversation, it doesn’t currently build against libutempter so it’s posdible to create a lot of detached sessions and not realise.

@sn00pster OK.

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