GitHub - fzakaria/selfdb

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2 min read Original article ↗

SELF — the Structured Executable & Linkable Format: a program that is a SQLite database instead of an ELF file, and the machinery to actually run it on Linux/NixOS.

sqlelf (arXiv:2405.03883) put a SQL view over ELF. This project inverts it: the rows are the format, a binfmt_misc interpreter executes them, and nixpkgs/NixOS is the vehicle to run a real slice of a system on it.

$ file hello
hello: SQLite 3.x database, application id 0x53454c46, user version 1
$ ./hello
Hello, world!
$ sqlite3 hello 'SELECT soname FROM ldd'          # ldd, as a query
$ sqlite3 hello 'DELETE FROM sections; VACUUM'    # strip, as a transaction
$ ./hello                                         # still runs
Hello, world!

What's here

  • converter/ — elf2self, self2elf, and the self CLI (Python + LIEF).
  • loader/ — self-exec, the binfmt interpreter, with three modes: memfd (rebuild ELF → execveat), native (map segments + hand off to ld.so), selfld (be the dynamic linker, bind via SQL). Plus libself-audit.so, an LD_AUDIT library that makes stock glibc load .self shared libraries resolved through SQL.
  • nix/ — packages, a selfify hook, a NixOS module (programs.self), and self-vm.
  • schema/self.sql — the format DDL (generated from selfconv/schema.py).
  • examples/server/ — self-httpd: a webserver whose pages, program and visitor log are one file. It opens argv[0] as a database and serves out of its own routes table; editing the live site is an UPDATE. Live at https://selfdb.exe.xyz.
  • bench/, tests/ — the evaluation harness and the test suite.

Read DESIGN.md; §13 tracks implementation status.

Try it

$ nix develop                        # dev shell (converter + loader + tools)
$ nix develop -c bash tests/all.sh   # run M0..M3b end to end
$ nix develop -c bash tests/showcase.sh
$ nix run .#self-vm                  # a NixOS VM where ./hello.self just runs
                                     # (login: root, empty password)

$ bash examples/server/build.sh ./server   # a website, inserted into a program
$ loader/self-exec ./server 8080           # http://localhost:8080