ubuntu-phone team mailing list archive

[Zoltán Balogh <zoltan.balogh@xxxxxxxxxxxxx>]

Hi,

Alberto Mardegan (mardy) has pinged us about the $subject and I think it 
worth to bring this idea to the community :)

So mardy and zbenjamin (big hands to both) made a study

mardy's findings were ->

"The idea is to turn the application binaries into shared modules, whose 
exported symbol is their "main" function only (or they can remain as an 
executable, as long it's a position independent -pie exporting the 
"main" function).
In the .desktop files, we replace the value of the Exec command with 
something like this:
Exec=invoker --type=qt ./myapp "invoker" is a simple client which talks 
to a daemon over a socket, and instructs the daemon to load "myapp" into 
its memory and run it.
The advantage of doing this, is that the daemon has already forked off 
into a process which has the Qt libraries loaded, also with the 
QGuiApplication and QQuickView objects instantiated (and possibly also 
the ubuntu-ui-toolkit components loaded and compiled).
The "--type" parameter selects which daemon to talk to: since we can 
have different types of applications (Qt, QML, QML with ubuntu 
components, SDL, Cordova, etc.) we can have more than one daemon (called 
"booster"), each one serving a specific type of application. We don't 
need to have all possible types of boosters running; we can optimize 
just for the most common application types.
As an example, here are the boosters used in Sailfish: [1] [2] [3]
The booster daemons work by forking off into a child process which loads 
the common libraries and does all the possible initializations.
Then it waits for a client (provided by the invoker binary) to connect 
over a socket, and when this happens the child process loads the desired 
application and starts running it.
The daemon could also read the client's apparmor profile and set it on 
the child process before starting executing main()."

So I made simple and far from perfect packaging branches for these 
projects [4] and pushed the source packages to the SDK's Staging PPA [5]

I know that there are security concerns about how the mapplauncherd 
works.  After talking to the main developer (w00t on freenode) and 
reviewing the code I have learned what the mapplaucnher is doing [7]

If you have any experience or opinion about the topic please bring it up :)

This idea looks very promising and piling off seconds from the app 
starts is something we all are interest, but obviously not for the price 
of compromising our platform's security.

cheers,

bzoltan


[1] https://github.com/nemomobile/mapplauncherd
[2] https://github.com/nemomobile/mapplauncherd-qt
[3] https://github.com/nemomobile/mapplauncherd-booster-qtcomponents
[4] https://code.launchpad.net/~ubuntu-sdk-team/mapplauncherd/
[5] 
https://launchpad.net/~ubuntu-sdk-team/+archive/ubuntu/staging/+packages?field.name_filter=applauncher
[6] http://pastebin.ubuntu.com/11953953/
[7] http://pastebin.ubuntu.com/11953814/