Preserve random seed across reboots
At first I tried to just use systemd's systemd-random-seed, but that one
does not actually use an appropriate ioctl for persuading kernel that
entropy is there. There's a patch [1] for this, but its fate is far from
certain, and even with it, I am not completely sure that I got
everything working correctly (some boots were quick, others waited for
systemd-resolved in the same manner as before this patch).
In the end, just seeding stuff from the initrd [2] is much easier. A
downside is that the systemd unit systemd-random-seed.service will add
the contents of that file once again -- but that doesn't matter much
because we do not patch it, and therefore it does not increase kernel's
idea about available entropy.
Changes from that upstream rndaddentropy:
- larger buffer
- more conservative entropy contribution
[1] https://github.com/systemd/systemd/pull/10621 .
[2] https://github.com/rfinnie/twuewand/blob/master/rndaddentropy/rndaddentropy.c
Change-Id: Ibe3c926c241d75fb7d7c40f3df2a96813931971b
diff --git a/configs/czechlight_clearfog_defconfig b/configs/czechlight_clearfog_defconfig
index 0e547fa..bf75605 100644
--- a/configs/czechlight_clearfog_defconfig
+++ b/configs/czechlight_clearfog_defconfig
@@ -6,6 +6,7 @@
BR2_ENABLE_DEBUG=y
BR2_STRIP_EXCLUDE_FILES="cla-* netopeer2* sysrepo* libsysrepo* libSysrepo* libnetconf2* libyang* netconf-cli"
BR2_STRIP_EXCLUDE_DIRS="/usr/lib/libyang /usr/lib/sysrepo"
+BR2_GLOBAL_PATCH_DIR="$(BR2_EXTERNAL_CZECHLIGHT_PATH)/board/czechlight/common/patches"
BR2_REPRODUCIBLE=y
BR2_SSP_STRONG=y
BR2_TOOLCHAIN_EXTERNAL=y
@@ -52,6 +53,7 @@
BR2_PACKAGE_RAUC=y
BR2_PACKAGE_RAUC_NETWORK=y
# BR2_PACKAGE_SYSTEMD_HWDB is not set
+BR2_PACKAGE_SYSTEMD_RANDOMSEED=y
# BR2_PACKAGE_SYSTEMD_VCONSOLE is not set
BR2_PACKAGE_VIM=y
# BR2_PACKAGE_VIM_RUNTIME is not set