06 Jan 2018

Another year is gone with Jehanne.

Here is a little report of what has been done (in no particular order):

• everybody’s copyrights have been made explicit and hopefully correct
• several bugs have been fixed (and probably more introduced)
• kernel options management has been simplified
• boot assembly has been rewritten
• swap support have been removed
• MCACHE support for mount has been removed
• various improvements have been imported from 9front (MMU management, PCI, AHCI, interruptible locks…) and 9front’s pstree has been ported
• the awake system call has been generalized to interrupt several blocking syscalls, even during note handling
• tsemacquire has been moved to libc (in less than 15 lines)
• no rendezvous can occur at the tag ~0
• the names of the procedures provided by the native C library has been prefixed with “jehanne_”, to define a namespace that avoid collisions with other C libraries (so that new programs can use for example both a POSIX C library and the Jehanne’s libc)
• the name space of a process you own can be cloned writing “clone” to its /proc/$pid/ns
• LibPOSIX has been introduced
• RedHat’s newlib has been ported to Jehanne on top of LibPOSIX
• MirBSD Korn Shell has been ported to Jehanne on top of newlib

Some of these changes are more heretic than others, but all are designed to make the system simpler and more useful at the same time.

The generalization of awake allows the implementation in userspace of a wide range of features usually found in unix kernels.
For example, LibPOSIX can use it to provide non blocking I/O and to implement sigtimedwait.

The removal of swap and mount(MCACHE) simplifies the kernel and increases security.

MirBSD Korn Shell

Despite the various tests I wrote for newlib, I wanted a real world application to check the quality of LibPOSIX.

I choose mksh for two reasons:

1. it’s simple and powerful
2. it’s developed by a great hacker that actively helped me even to understand the weird semantics I had to implement

Thanks Thorsten!

If you want to give it a try, run in rio: vt sys/posixly mksh -l.

(to get rio on boot: cp /arch/rc/lib/startup/terminal /cfg/startup)

New year’s resolutions for 2018

Funny ones:

• keep stealing from 9front improve hardware support
• add O_NONBLOCK support to LibPOSIX (and newlib) on top of the awake system call
• draft the new file protocol that will replace both HTTP and 9P2000
• move the existing 9P2000 server to this new protocol
• create new file servers to read/write at least Linux Ext2 and NTFS with the new protocol

Duties:

• write about the awake system call (as promised one year ago)
• write what I want to forget about LibPOSIX
• write or port a package manager
• port GCC and friends on top of newlib/LibPOSIX
• turn Jehanne in a self-hosted OS
• write documentation and manual
• add screenshots to the website
• more tests

Under evaluation:

• port pkgsrc
• port discount
• port musl
• port ncurses
• port vim
• port OBNC (and replace Go with Wirth’s Oberon-07)
• port… more Free Software

Boring task:

• write the equivalent of lib9p for the new file protocol
• write an alarm file server on top of the new file protocol and remove alarm from the kernel
• fix bugs

Real promises:

• more crazy ideas
• break the build
• sleep

Who guess what will be actually done?