If snapd is not working it can take down systemd

[Henry Wertz]

I'll start out with saying, this bug is probably priority "invalid" due to my non-stock configuration (this 18.04.1 install is on an Acer Chromebook 13, so it has a held back kernel and Xorg for the lovely nvidia drivers it came with.) But I figure I'll file anyway since the problem is rather serious if it arises on your particular system, and the workaround/fix is easy once you figure out what the heck is happening.

So, snapd has errored out since I updated to 18.04 due to my held back kernel (snap packages are using xz compression, and this kernel has no xz support...) I found within the last day or so that my machine would not boot to graphical environment, just to text login with no networking up and several missing services (ntp and a few others.) journalctl -xe showed failures due to "file not found" on files like tr, cut, modprobe, cat, that should definitely be found. PATH problems! Ultimately, I found /usr/lib/systemd/system-environment-generators/snapd-env-generator (which appears -- not sure since it's a binary instead of a shell script -- to be intended to just add "/snap/bin" to the PATH.) I moved this out of the folder, on reboot everything worked fine. Then I went ahead and uninstalled snapd.

I suspect systemd is "too smart for it's own good", and instead of providing it's own environment variables then letting items in /usr/lib/systemd/system-environment-generators/ modify the environment (as docs say), instead systemd either decided "snapd-env-generator" is setting a PATH so systemd doesn't have to (resulting in PATH of ":/snap/bin") or systemd "rolled back" that PATH when snapd service failed, resetting PATH to empty instead of the default PATH value.

[Dimitri John Ledkov (xnox)]

yeah, there is/was a bug in both systemd and snapd w.r.t. injecting :/snap/bin. I believe it is fixed in cosmic already, and bionic should be fixed soon too. I will mark this report as a duplicate.