libfakeext4

Just a dumb thing to fake the type of a filesystem

Intro

Dropbox will no longer allow running the Linux client on any filesystem other than Ext4 (forum thread, Reddit thread). Ext4 is garbage. So, just pretend we're running dropbox on an Ext4 filesystem.

Usage

Compile library

Compile this using cmake, e.g. in a temp directory (starting from this repo):

dir="$(pwd)"
cd "$(mktemp -d -t build-fakeext4.XXXXXXXX)"
cmake "$dir"
make

Install it

(optional, but definitely easiest):

make install
## default prefix = /usr/local
## library file = ${prefix}/lib/libfakeext4.so

Ensure dropboxd uses it

Ensure it's in dropboxd's LD_PRELOAD environment variable. E.g., via a systemd user unit drop-in file:

config_dir=$HOME/.config/systemd/user/dropbox.service.d
mkdir -p "$config_dir"
cat > "$config_dir/environment.conf" <<'CONFIG'
[Service]
Environment=LD_PRELOAD=/usr/local/lib/libfakeext4.so
CONFIG

Features and TODOs

• Successfully intercepts libc calls
• Intercepts raw syscalls on x86_64 Linux
• Prevents dropboxd from popping up a warning about impending failure
• Keeps working after the "drop-dead" date
• Check into overriding statvfs f_fsid field

License

Copyright © 2018 Benjamin R. Haskell

Distributed under the MIT License (included in file: LICENSE).