• ServerProcess

Server process

In Plash, a sandboxed process's access is mediated through a server process. When a sandboxed process wishes to open a file, it sends a message to the server process, which may send back a file descriptor in response.

Examples of programs providing server processes are pola-run and plash-pkg-launch.

The server process is not a distinct component of Plash. The term just describes the process's relationship to a sandboxed process.

A server process typically contains a stack of objects: FsOp handles requests from PlashGlibc in the sandboxed process. FsOp typically has a reference to a FsObjMountTable directory object. Individual FsObjReal objects (perhaps wrapped by FsObjReadOnly) might be attached to the FsObjMountTable in order to grant them to the sandboxed process.

Server processes can run inside or outside sandboxes. Server processes may be chained together in the case of NestedSandboxes.

Terminology

To do: Consider changing the terminology. "Mediator process" might be a better term than "server process". In the Ostia paper the term "agent" is used.