nixos/etc: skip resolv.conf in nixos-enter chroot

nixos-enter sets up /etc/resolv.conf as a bind mount from the host
system, so trying to activate a system that sets
`environment.etc."resolv.conf"` (e.g. with systemd-resolved enabled)
results in an unhelpful warning.

Skip linking /etc/resolv.conf if we're in a nixos-enter environment, as
determined by the IN_NIXOS_ENTER environment variable.

Make the warnings more helpful, indicating which file we failed to link.

Unlink temporary files in case of failure.
This commit is contained in:
Naïm Favier 2023-01-02 01:41:29 +01:00
parent 5a9a335334
commit 37e42d01a0
No known key found for this signature in database
GPG Key ID: 95AFCE8211908325

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@ -13,8 +13,12 @@ sub atomicSymlink {
my $tmp = "$target.tmp";
unlink $tmp;
symlink $source, $tmp or return 0;
rename $tmp, $target or return 0;
return 1;
if (rename $tmp, $target) {
return 1;
} else {
unlink $tmp;
return 0;
}
}
@ -87,6 +91,12 @@ my @copied;
sub link {
my $fn = substr $File::Find::name, length($etc) + 1 or next;
# nixos-enter sets up /etc/resolv.conf as a bind mount, so skip it.
if ($fn eq "resolv.conf" and $ENV{'IN_NIXOS_ENTER'}) {
return;
}
my $target = "/etc/$fn";
File::Path::make_path(dirname $target);
$created{$fn} = 1;
@ -103,7 +113,7 @@ sub link {
if (-e "$_.mode") {
my $mode = read_file("$_.mode"); chomp $mode;
if ($mode eq "direct-symlink") {
atomicSymlink readlink("$static/$fn"), $target or warn;
atomicSymlink readlink("$static/$fn"), $target or warn "could not create symlink $target";
} else {
my $uid = read_file("$_.uid"); chomp $uid;
my $gid = read_file("$_.gid"); chomp $gid;
@ -112,12 +122,15 @@ sub link {
$gid = getgrnam $gid unless $gid =~ /^\+/;
chown int($uid), int($gid), "$target.tmp" or warn;
chmod oct($mode), "$target.tmp" or warn;
rename "$target.tmp", $target or warn;
unless (rename "$target.tmp", $target) {
warn "could not create target $target";
unlink "$target.tmp";
}
}
push @copied, $fn;
print CLEAN "$fn\n";
} elsif (-l "$_") {
atomicSymlink "$static/$fn", $target or warn;
atomicSymlink "$static/$fn", $target or warn "could not create symlink $target";
}
}