Previously: the service wrote a timestamp and the receiver
read and parsed it to see if there was new data
Now: the service writes and removes a .lock file to prevent
the receiver reading partial data. The receiver is responsible
for remembering the *previous* state and only updating if it's changed
this is step 1 of min-collect-garbage, no point implementing
deletion ourselves when rm -r exists
(arguably no point in implementing any of it, but this is the bit we
can't do efficiently in bourne shell - it means we're reading the
store-paths list once instead of grepping it afresh for every entry in
/nix/store/)
By using the kernel "nolibc" header to avoid requiring a C library, we
can bring the initramfs size to around 4k
This does involve a tiny bit of inline mips assembly which I'm not
sure about. gcc seems unwilling to generate the code to load $gp at
function entry of main(), so we do it by hand - but I'd rather find
out why gcc doesn't.
systemconfig (a.k.a "activate") is run from the initramfs. Converting
it from a shell script to an executable means it doesn't depend on
there being a shell in the initramfs
the jffs2 filesystem contains only /nix/store and a script which is
run in early init (initramfs) and is responsible for recreating
"traditional" directories (/bin /etc/**/* /var &c) based on the
configuration.
this is tested only in qemu so far and could use some cleanup
we'd like a bit more of the convenience of mksquashfs
(never thought I'd say _that_) for jffs2, in particular
not having to copy all the desired store paths into a
single directory just so we can create an image from them
We now use MIPS_CMDLINE_DTB_EXTEND for all boot varieties
(tftpboot, flash boot, kexec) with the addition of
MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE - local patch -
so that the bootloader args are ignored unless they
contain the string "liminix"
This allows booting a new image from a running OS, creating a
phram mtd for the root squashfs
* enable CONFIG_KEXEC
* add modules/kexecboot
* patch kexec-tools to add --map-file option for the squashfs
* patch kernel kexec code to call new kernel with DTB
