From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/3649 Path: news.gmane.org!not-for-mail From: Rob Landley Newsgroups: gmane.linux.lib.musl.general Subject: embedded newbies site. Date: Mon, 15 Jul 2013 21:03:34 -0500 Message-ID: <1373940214.3719.5@driftwood> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; DelSp=Yes; Format=Flowed Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1373940233 1867 80.91.229.3 (16 Jul 2013 02:03:53 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 16 Jul 2013 02:03:53 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-3653-gllmg-musl=m.gmane.org@lists.openwall.com Tue Jul 16 04:03:55 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1UyucN-0000Y8-DG for gllmg-musl@plane.gmane.org; Tue, 16 Jul 2013 04:03:55 +0200 Original-Received: (qmail 5687 invoked by uid 550); 16 Jul 2013 02:03:53 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 5660 invoked from network); 16 Jul 2013 02:03:50 -0000 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=date:from:subject:to:x-mailer:message-id:mime-version:content-type :content-disposition:content-transfer-encoding:x-gm-message-state; bh=NrrADdd0Zmb7YMC+vAPsEnHl0HJxY4gbrP9vyu/eJUo=; b=V10oK4n/+XQkgWRh/aw/CGGADI2JT9pK25BHh/TWj15iON2oIuOiwEOivTB+VxhGpH +0UYsLUgJyPWP5G0u+vvZJ9lxNhb1iosc9IITfkjFRe5wjIjySO5JfXOYHCvqYh3PqgE rmaUtfPu4g4+ZK5x0YJukpdklh/ITr8tHxYMbDRzGHBomUIwEzfxkqB4tRpNf4iFM30L 8EJ84Kt9osfD/FdjF0VzP55810nag+FbdKYfAxNEdewXj9DdcB19nVENiyF+3mpWrieu HoWxdeaGwlRul3KOAPnSqLmcyla4fTIHNTy94u/RB5O2D1VZ58eGFlsq/vkI+xsEIO6l nTEQ== X-Received: by 10.50.85.114 with SMTP id g18mr8798122igz.14.1373940218437; Mon, 15 Jul 2013 19:03:38 -0700 (PDT) X-Mailer: Balsa 2.4.11 Content-Disposition: inline X-Gm-Message-State: ALoCoQktGGrs0S7syNNWNg5x76EZJhqTdbI+3kriNRzNxhUbXDZfBKfetMTdLffkTpX0fME2/TTD Xref: news.gmane.org gmane.linux.lib.musl.general:3649 Archived-At: As I was ruminating on IRC: Once upon a time the busybox/uClibc community provided a condensation =20 nuclei for most embedded Linux development: website, mailing list, and =20 #uclibc irc channel here on freenode. But that fell apart in 2005 =20 (buildroot was one project too many, openwrt was separate and based on =20 the horrible linksys build system, various corporate efforts like Maemo =20 and Moblin and OpenMoko did their own thing...) A lot of the stuff I learned about embedded development would be hard =20 to replicate today because there's no community aimed at bringing =20 newbies up to speed on this stuff. I know we've got a wiki page =20 collecting other interesting packages that work with musl, but there's =20 more to it than that. My path to embedded development went like something this: 1) remove unnecessary packages from existing distros 2) copy files into an empty directory to make a working chroot that =20 runs my app 3) build Linux From Scratch from source 4) swap in busybox and uClibc in LFS, remove unnecessary stuff, =20 customize result It would be nice to have a site walking people through these steps, and =20 hosting an "Embedded Linux From Scratch" as a wiki, and with associated =20 mailing list and IRC channel. (It was sort of #edev for a while, but =20 now #musl is more active but half the discussion on it is off topic...) I'd like an explicit a place to collect and preserve information about =20 this sort of thing, and a place we can send newbies to ask all the =20 stupid questions. The main page should teach somebody what embedded =20 development _is_ and how to do it, starting with how to build and =20 install the simplest Linux system that boots to a shell prompt (three =20 packages: linux, musl, and toybox). Then there should be additional modules people can pick and choose from: - analyzing an existing system - creating a chroot with ldd - your friend strace - why PID 1 is special, init via shell script, classic system V =20 init. - what's in /etc, /var, /usr, /bin, /lib, /tmp - intro to relevant standards - what/where are posix, lsb, fhs, elf... plus a ~3 paragraph =20 summary of each. - a tour of libc - readelf -a, static vs dynamic, the dynamic linker - man 2 vs man 3, stdio subsystem, -lpthread - a tour of the kernel - yeah yeah, can 'o worms, but =20 http://kernel.org/doc/single/lki-single.html needs a brand new version for 3.x. - a tour of compiler toolchains - the six paths, why a docbook->pdf converter and toolchain =20 aren't different. - creating a development environment (building binutils, gcc, =20 make...) - requirements for self-hosting - requirements for natively building Linux From Scratch - cross vs native compiling - bootstrapping to native compiling under emulation. - cross compiling for non-x86 systems (with qemu) - bootloaders, jtags, - booting a simple gui - fishing the x11 stuff out of BLFS, booting fvwm or dwm or =20 something. - getting client-side networking working - ifconfig, route, iwlist, iwconfig, maybe wpa-supplicant... - setting up a server - iptables - apache, postfix, samba - reproducing android userspace - root vs non-root - processes, files, suid, sgid, sticky bit - security nuttiness - selinux, extended attributes, apparmor, capability bits - containers: not doing any of that - why "users" and "groups" wasn't good enough. - efficient (elegant) programming - Why C and scritpting languages, why NOT C++ and autoconf - tradeoffs - code reuse - transaction granularity - taking advantage of SMP without going crazy Yeah yeah, a lot of this is listing stuff I could write, but the point =20 is there's lots of stuff I can't write and don't know, and there should =20 be other people who can answer questions... I bump into stuff like suckless and hope it'll turn into this, but so =20 far it hasn't... Rob=