Create Sealable In-Memory Files on Linux with memfd_create

Sat, 05 Sep 2026 00:00:00 +0700

Applications often need a temporary chunk of data that behaves like a file without needing a persistent pathname. A process may build a configuration snapshot, compiled artifact, or serialized message, then map it into memory or pass it to another process.

A regular temporary file can do that, but it introduces filesystem naming, cleanup, permissions, and lifetime concerns. An anonymous mmap() avoids the pathname, but it does not produce an ordinary file descriptor that can be passed to APIs expecting file-backed data.

Pass Open File Descriptors Between Linux Processes with SCM_RIGHTS

Sat, 05 Sep 2026 00:00:00 +0700

Processes often need to hand each other access to an already-open resource. A supervisor may accept a client connection and delegate it to a worker. A privileged helper may open a protected file, then give an unprivileged process access without revealing broader filesystem permissions. A service may create an anonymous in-memory file and transfer it to another process.

Sending the integer value of a file descriptor does not solve this problem. File descriptor numbers are meaningful only inside one process’s descriptor table. Descriptor 7 in one process can refer to a socket while descriptor 7 in another process refers to an unrelated file.

IPC on Nalar

Create Sealable In-Memory Files on Linux with memfd_create

Pass Open File Descriptors Between Linux Processes with SCM_RIGHTS