nixos/etc: Make symlinks relative instead of absolute

so that the links can be followed if the NixOS installation is not mounted as filesystem root.
In particular, this makes /etc/os-release adhere to the standard:
https://www.freedesktop.org/software/systemd/man/os-release.html
Fixes #28833.
This commit is contained in:
Florian Jacob 2018-11-13 10:13:23 +01:00 committed by danbst
parent 2e76049491
commit fc8e1745c0
4 changed files with 29 additions and 8 deletions

View file

@ -457,6 +457,14 @@
use <literal>nixos-rebuild boot; reboot</literal>.
</para>
</listitem>
<listitem>
<para>
Symlinks in <filename>/etc</filename> are now relative instead of absolute,
so that the links can be followed if the NixOS installation is not mounted as filesystem root.
In particular, this makes <filename>/etc/os-release</filename> adhere to
<link xlink:href="https://www.freedesktop.org/software/systemd/man/os-release.html">the standard</link>.
</para>
</listitem>
<listitem>
<para>
Flat volumes are now disabled by default in <literal>hardware.pulseaudio</literal>.

View file

@ -40,7 +40,7 @@ for ((n = 0; n < ${#objects[*]}; n++)); do
symlink=${symlinks[$n]}
if test "$symlink" != "none"; then
mkdir -p $(dirname ./$symlink)
ln -s $object ./$symlink
ln -s --relative ./$object ./$symlink
fi
done

View file

@ -10,6 +10,11 @@ users_=($users)
groups_=($groups)
set +f
# Create relative symlinks, so that the links can be followed if
# the NixOS installation is not mounted as filesystem root.
# Absolute symlinks violate the os-release format
# at https://www.freedesktop.org/software/systemd/man/os-release.html
# and break e.g. systemd-nspawn and os-prober.
for ((i = 0; i < ${#targets_[@]}; i++)); do
source="${sources_[$i]}"
target="${targets_[$i]}"
@ -19,14 +24,14 @@ for ((i = 0; i < ${#targets_[@]}; i++)); do
# If the source name contains '*', perform globbing.
mkdir -p $out/etc/$target
for fn in $source; do
ln -s "$fn" $out/etc/$target/
ln -s --relative "$fn" $out/etc/$target/
done
else
mkdir -p $out/etc/$(dirname $target)
if ! [ -e $out/etc/$target ]; then
ln -s $source $out/etc/$target
ln -s --relative $source $out/etc/$target
else
echo "duplicate entry $target -> $source"
if test "$(readlink $out/etc/$target)" != "$source"; then
@ -34,13 +39,13 @@ for ((i = 0; i < ${#targets_[@]}; i++)); do
exit 1
fi
fi
if test "${modes_[$i]}" != symlink; then
echo "${modes_[$i]}" > $out/etc/$target.mode
echo "${users_[$i]}" > $out/etc/$target.uid
echo "${groups_[$i]}" > $out/etc/$target.gid
fi
fi
done

View file

@ -4,6 +4,7 @@ use File::Copy;
use File::Path;
use File::Basename;
use File::Slurp;
use File::Spec;
my $etc = $ARGV[0] or die;
my $static = "/etc/static";
@ -12,7 +13,13 @@ sub atomicSymlink {
my ($source, $target) = @_;
my $tmp = "$target.tmp";
unlink $tmp;
symlink $source, $tmp or return 0;
# Create relative symlinks, so that the links can be followed if
# the NixOS installation is not mounted as filesystem root.
# Absolute symlinks violate the os-release format
# at https://www.freedesktop.org/software/systemd/man/os-release.html
# and break e.g. systemd-nspawn and os-prober.
my $rel = File::Spec->abs2rel($source, dirname $target);
symlink $rel, $tmp or return 0;
rename $tmp, $target or return 0;
return 1;
}
@ -30,7 +37,8 @@ sub isStatic {
if (-l $path) {
my $target = readlink $path;
return substr($target, 0, length "/etc/static/") eq "/etc/static/";
my $rel = File::Spec->abs2rel("/etc/static", dirname $path);
return substr($target, 0, length $rel) eq $rel;
}
if (-d $path) {