faked-sysv

Not typically invoked directly by users.
Internally used by the fakeroot(1) command to manage System V IPC objects within a simulated root environment.

None
    faked-sysv is an internal helper program and does not expose user-configurable command-line parameters. It communicates internally with the fakeroot daemon via environment variables and IPC mechanisms (e.g., UNIX domain sockets) to manage the fake IPC state.

faked-sysv is a utility program that forms an integral part of the fakeroot package. Its primary function is to intercept and manage System V IPC (Inter-Process Communication) calls, including semaphores, message queues, and shared memory, when a process is running within the fakeroot environment. While fakeroot itself effectively simulates root privileges for file system operations, direct System V IPC objects are kernel-level resources that cannot be faked in the same manner. faked-sysv works in conjunction with fakeroot to provide a comprehensive fake root environment by mapping IPC object IDs and ensuring that operations appear to succeed as if performed by a privileged user, without requiring actual root privileges. Users typically do not invoke faked-sysv directly; it is automatically launched and managed by the fakeroot(1) command as needed to ensure consistent behavior for IPC-intensive applications.

Caveats and Limitations:
Not for Direct Use: faked-sysv is not designed for direct user interaction or standalone execution. Running it manually is unlikely to be useful and may lead to unexpected behavior.
System V IPC Only: This utility specifically addresses System V IPC mechanisms (semaphores, message queues, shared memory). It does not manage POSIX IPC or other inter-process communication methods.
Fakeroot Dependent: Its functionality is entirely dependent on the fakeroot environment. It has no purpose outside of being invoked by fakeroot.

faked-sysv operates by intercepting System V IPC-related system calls (such as semget, msgget, shmget, and their respective operations) made by programs running under fakeroot. Instead of allowing these calls to interact with the real kernel IPC facilities, faked-sysv maintains an internal, non-privileged state for IPC objects. This allows it to return fake IPC identifiers and manage permissions and ownership within the simulated root environment, ensuring that applications behave as if they are interacting with root-owned IPC objects. This interception is typically achieved through library preloading (LD_PRELOAD) by fakeroot.

faked-sysv was developed as an integral part of the fakeroot project, which aims to provide a means for unprivileged users to build software packages (like .deb or .rpm files) that contain files with root ownership and permissions. Initially, fakeroot primarily handled file system operations. However, some build processes and applications rely on System V IPC. The need for a comprehensive fake root environment led to the inclusion of faked-sysv to specifically address the challenge of simulating root privileges for System V IPC objects, thereby extending the capabilities of fakeroot to a wider range of scenarios.

fakeroot(1), ipcs(1), ipcrm(1), ipc(5)