From 980d2c57df3c5842a282fa57a3bc7ee4a4f031fe Mon Sep 17 00:00:00 2001 From: Brooks Davis Date: Wed, 24 Apr 2024 12:39:45 +0200 Subject: Status/2024Q1/libsys.adoc: Add report Reviewed by: status (Pau Amma ) Pull Request: https://github.com/freebsd/freebsd-doc/pull/372 --- .../en/status/report-2024-01-2024-03/libsys.adoc | 41 ++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 website/content/en/status/report-2024-01-2024-03/libsys.adoc diff --git a/website/content/en/status/report-2024-01-2024-03/libsys.adoc b/website/content/en/status/report-2024-01-2024-03/libsys.adoc new file mode 100644 index 0000000000..46275eb7aa --- /dev/null +++ b/website/content/en/status/report-2024-01-2024-03/libsys.adoc @@ -0,0 +1,41 @@ +=== libsys + +Contact: Brooks Davis + +The libsys project removes direct system calls from [.filename]#libc.so# and [.filename]#libpthread.so# (aka [.filename]#libthr.so#) to a separate [.filename]#libsys.so#. +This will: + + * Isolate language runtimes from the details of system call implementations. + * Better support logging and replay frameworks for systems calls. + * Support elimination of the ability to make system calls outside trusted code in the runtime linker and `libsys`. + +This work was initially inspired by a compartmentalization prototype in CheriBSD in 2016. +Ali Mashtizadeh and Tal Garfinkel picked that work up and attempted to upstream it (link:https://reviews.freebsd.org/D14609[D14609]). +Unfortunately we could not figure out how to review and land the massive reorganization required through a phabricator review so it languished. +Last year the CHERI project once again found a need for system call separation in a new library-based compartmentalization framework in CheriBSD so I rebuilt the patch from scratch, committing dozens of `libc` cleanups along the way. +I landed the first batch of changes on February 5th. +Since then I have made a number of refinements to the way we link `libsys` as well as which symbols are provided in which library. + +Thanks to mailto:kib@FreeBSD.org[Konstantin Belousov] for many rounds of review and feedback as well as runtime linker fixes. +Thanks to mailto:markj@FreeBSD.org[Mark Johnston] for runtime linker debugging and mailto:dim@FreeBSD.org[Dimitry Andric] for sanitizer fixes. +Thanks also to everyone who reported bugs and helped debug issues. + +==== Known issues (as of the end of the reporting period) + + * The `libsys` ABI is not yet considered stable (it is safe to assume `__sys_foo()` will be supported so language runtimes can use it now). + * Programs using the address sanitizer must be linked with `-lsys` (resolved in base at publication time). + +==== TODO + + * Add a [.filename]#libsys.h#. (See link:https://reviews.freebsd.org/D44387[D44387] and other reviews in the stack.) + * Update man:intro[2] for `libsys`. + * Finalize the ABI. + I am likely to reduce the set of `_` (underscore) prefixed symbols we expose. + * MFC the existence of `libsys`? It is not clear this is practical, but it might be possible to MFC something useful for language runtimes. + +==== Help wanted + + * Port language runtimes that do not use `libc` to use `libsys` for system calls rather than rolling their own interfaces. + * Explore limitations on where system calls can be made similar to OpenBSD's link:https://man.openbsd.org/OpenBSD-7.3/msyscall[msyscall(2)] (now obsolete) and link:https://man.openbsd.org/pinsyscalls[pinsyscalls(2)] (not an obvious match to our `libsys`). + +Sponsor: AFRL, DARPA -- cgit v1.2.3