libwrapdroid

System V and Posix shared memory wrapper for chrooted environments (i.e.: PRoot) under Android. Supposed to be an extended version of https://github.com/termux/libandroid-shmem

• Android 10 and higher support (not relied upon ashmem): see https://developer.android.com/about/versions/10/behavior-changes-10#shared-memory
• Resouces are linked to a server instance and will be freed at the instance exit.
• Each server instance provides its own namespace.
• System V shared memory calls: shmget(), shmat(), shmdt(), shmctl():
  • There are some problems around process termination and fork() but it serves Xwayland + XFCE + Firefox without any visible problems even in its current state.
    (Full support will be added in the next version.)
• Posix shared memory calls: shm_open(), shm_unlink().

Build

Under PRoot:

make PREFIX=/opt/shm install

Parts

• libwrapdroid-server — is to be started to create a resource namespace.
• libwrapdroid-shm-posix.so — Posix shared memory API; to be added to LD_PRELOAD.
• libwrapdroid-shm-sysv.so — System V shared memory API; to be added to LD_PRELOAD.

Environment variables

• LIBWRAPDROID_SOCKET_NAME — communication socket name in the abstract namespace.
  (must be set per server instance)
• LIBWRAPDROID_AUTH_KEY — authentication key (at least 16 hex digits length).
  (must be set per server instance)