Play with the userfaultfd(2) system call and download on demand using HTTP Range Requests with Golang
a project by rbranco
Updated 27 days ago. 2 hacker ♥️. 1 follower.

Description

The userfaultfd(2) is a cool system call to handle page faults in user-space. This should allow me to list the contents of an ISO or similar archive without downloading the whole thing. The userfaultfd(2) part can also be done in theory with the PROT_NONE mprotect + SIGSEGV trick, for complete Unix portability, though reportedly being slower.

Goals

  1. Create my own library for userfaultfd(2) in Golang.
  2. Create my own library for HTTP Range Requests.
  3. Complete portability with Unix.
  4. Benchmarks.
  5. Contribute some tests to LTP.

Resources

  1. https://docs.kernel.org/admin-guide/mm/userfaultfd.html
  2. https://github.com/loopholelabs/userfaultfd-go
  3. https://github.com/DHowett/ranger
  4. https://www.cons.org/cracauer/cracauer-userfaultfd.html

Join this project

Looking for hackers with the skills:

golang userfaultfd go

This project is part of:

Hack Week 25

Activity

  • 9 days ago: barendartchuk liked this project.
  • 25 days ago: hennevogel liked this project.
  • 26 days ago: rbranco added keyword "go" to this project.
  • 27 days ago: rbranco started this project.
  • 27 days ago: rbranco added keyword "golang" to this project.
  • 27 days ago: rbranco added keyword "userfaultfd" to this project.
  • 28 days ago: rbranco originated this project.


    • Comments

    • rbranco
      28 days ago by rbranco | Reply

      Golang library for userfaultfd created: https://github.com/ricardobranco777/go-userfaultfd

    • rbranco
      10 days ago by rbranco | Reply

      Created a simple library for doing HTTP Ranges without a cache: https://github.com/ricardobranco777/httpseek

      OTOH:

      • Making this portable by using SIGSEGV is not doable in Golang, which reserves this signal to itself.

      • This is overkill even for even the use-case of random seeks. There's overhead with paging in user-space and system calls.

      Scaling back the original goals to:

      • Benchmark Move vs Copy.

      • Provide a comprehensive test-suite to LTP.

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