Bug#983435: Regarding the backup/restore function

[bugsgrid+deb at gmail.com]

On Fri, 26 Feb 2021 15:21:59 +0000
Dimitri John Ledkov <dimitri.ledkov at canonical.com> wrote:

>are grub.mo from grub-common somehow excluded on the system?

I have no idea, I don't have localepurge installed on that machine.
I belive those missing grub.mo's are actually not in debian's
grub-common, or rather, not in the entire debian archive.  At least,
packages.debian.org/search doesn't show e.g. /fa/LC_MESSAGES/grub.mo
anywhere anysuite, so no one in debian world should have that file...?

Being just a router, the machine have very minimum packages installed
(besides gcc to compile kernel), so there may be some missing
executables used by grub-install.  For reference, the list of
installed packages (distilled from /var/lib/dpkg/status of the disk
image) is pasted below.

>For me to avoid doing it on_exit()
>would mean to rewrite all the places where grub_install tries to exit
>to try to do cleanups & restores. Would doing it in grub-install
>without on_exit inspire more confidence, or guarding to only do
>anything in the main_pid of grub-install? Should the log of actions be
>maintained and then rolled back only if they can be?

I'm not familiar to codes, take with a grain of salt:

Given the structure of upstream code, entirely avoiding on_exit()
would result to more intrusive patch.
As for log-and-rewind strategy (with or without on_exit)... I thought
that first, but then isn't it better to stop creating new installs
in-place from the very first?  Instead create new in temporary, and
finally swap old with new.  As the modules directory should once have
been created by grub-install itself, I thought we're allowed to move
it around, and then we don't have to track all of individual old
files...?

But for now, guarding by main_pid, patching up every fork()'s, and
proper logging for --verbose would be nice to have, I guess.  Of
course, BIG RED BOLD BANNER and couple of beeps should be put whenever
detected misfire :-)

Thanks in advance,

list of installed packages on my problematic router:
====
adduser apt aptitude aptitude-common attr base-files base-passwd bash
bc binutils binutils-common binutils-x86-64-linux-gnu bison
bsdmainutils bsdutils build-essential bzip2 conntrack
console-setup-linux console-setup-mini coreutils cpio cpp cpp-8 dash
debconf debian-archive-keyring debianutils dhcpcd5 diffutils dmsetup
dns-root-data dnsmasq dnsmasq-base dosfstools dpkg dpkg-dev e2fsprogs
ethtool fakeroot false-sendmail false-strongswan-starter
false-unbound-anchor fcron fdisk findutils flex g++ g++-8 gcc gcc-8
gcc-8-base gettext-base gpgv grep groff-base grub-common
grub-efi-amd64 grub-efi-amd64-bin grub2-common gzip hostname ifupdown
init init-system-helpers initscripts insserv iproute2
iputils-tracepath kbd keyboard-configuration kmod ldnsutils libacl1
libapt-pkg5.0 libasan5 libatomic1 libattr1 libaudit-common libaudit1
libbinutils libbison-dev libblkid1 libboost-iostreams1.67.0
libboost-system1.67.0 libbsd0 libbz2-1.0 libc-bin libc-dev-bin
libc-l10n libc6 libc6-dev libc6-i386 libcap-dev libcap-ng0 libcap2
libcap2-bin libcc1-0 libcom-err2 libcurl4 libcwidget3v5 libdb5.3
libdbus-1-3 libdebconfclient0 libdevmapper1.02.1 libdpkg-perl
libefiboot1 libefivar1 libelf1 libevent-2.1-6 libexpat1 libext2fs2
libfakeroot libfdisk1 libffi6 libfreetype6 libfuse2 libgcc-8-dev
libgcc1 libgcrypt20 libgdbm3 libglib2.0-0 libgmp10 libgomp1
libgpg-error0 libhogweed4 libidn11 libip4tc0 libip6tc0 libisl19
libitm1 libivykis0 libjansson4 libjson-c3 libkmod2 libldns2
liblocale-gettext-perl liblsan0 liblz4-1 liblzma5 libmnl0 libmount1
libmpc3 libmpdec2 libmpfr6 libmpx2 libncurses-dev libncurses6
libncursesw6 libnet1 libnetfilter-acct1 libnetfilter-conntrack3
libnetfilter-log1 libnettle6 libnewt0.52 libnfnetlink0 libnftables1
libnftnl11 libpam-modules libpam-modules-bin libpam-runtime libpam0g
libpcap0.8 libpcre3 libperl5.24 libpipeline1 libpng16-16 libpopt0
libprocps7 libprotobuf-c1 libpython3.7 libpython3.7-minimal
libpython3.7-stdlib libquadmath0 libreadline7 libselinux1
libsemanage-common libsemanage1 libsepol1 libsigc++-2.0-0v5
libsigsegv2 libslang2 libsmartcols1 libsqlite3-0 libss2 libssl-dev
libssl1.1 libstdc++-8-dev libstdc++6 libstrongswan
libstrongswan-standard-plugins libsystemd0 libtinfo6 libtsan0
libubsan1 libudev1 libustr-1.0-1 libutempter0 libuuid1 libwrap0
libxapian30 libxtables12 linux-image-4.19.171 linux-libc-dev
linux-source-4.19 locales login lsb-base lv m4 make makedev man-db
mawk mime-support mount ncurses-base ncurses-bin netbase nftables
ngetty openssl passwd patch perl perl-base perl-modules-5.24
pkg-config procps readline-common rng-tools5 screen sed sensible-utils
startpar strongswan-charon strongswan-libcharon strongswan-swanctl
syslog-ng-core syslog-ng-mod-getent syslog-ng-mod-journal sysv-rc
sysvinit-core sysvinit-utils tar tzdata ucf ulogd2 ulogd2-pcap unbound
util-linux watchdog whiptail xz-utils zlib1g zlib1g-dev
====
(note: false-* is dummies to shut up dpkg, but I'm fairly sure they're
not related to grub, never.)