[webkit-dev] webkitgtk and bubblewrap help needed

[Jack Hill]

Hi WebKit,

I'm working on an issue [0] in GNU Guix's WebKitGTK package. In the issue, 
I've identified what I believe to be a problem at the intersection of 
Bubblewrap, WebKitGTK, and Guix. I believe that the source of the problem 
is that with Guix, files that are needed in the sandbox are located in 
unexpected places. Everything manages by Guix, such as packages and 
configuration files, gets its own path under /gnu/store (answering why it 
is this way is a longer discussion which I'll leave to the manual [1] for 
now, but I find it compelling). Some files and directories under /run and 
/etc are symlinks to their canonical location under /gnu/store.

I believe that this arrangement will require extra paths to be bound into 
Bubblwrap's new mount namespace. However, it isn't clear to me what they 
are. I have tried patching BubblewrapLauncher.cpp, but it still seems to 
get tripped up with the pulse/client.conf symlink. I have not been able to 
reproduce the problem with simple interactive invocations of bwrap.

I'm interested in hearing how to troubleshoot problems like:

bwrap: Can't create file at /etc/pulse/client.conf: No such file or directory
bwrap: Can't mkdir parents for /run/current-system/profile/lib/gstreamer-1.0: No such file or directory

I'm also interested in hearing how to best integrate WebKitGTK with Guix. 
I suppose the ideal case is for WebKitGTK to detect situations like 
Guix's and call bwrap with the correct arguments, and to fall back to 
carrying a local patch in Guix if a general solution is not appropriate.

[0] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=40837
[1] https://guix.gnu.org/manual/en/html_node/Managing-Software-the-Guix-Way.html

Thanks,
Jack