nixpkgs/nixos/modules/system/activation/activation-script.nix
2020-11-24 12:42:06 -05:00

242 lines
6.4 KiB
Nix

# generate the script used to activate the configuration.
{ config, lib, pkgs, ... }:
with lib;
let
addAttributeName = mapAttrs (a: v: v // {
text = ''
#### Activation script snippet ${a}:
_localstatus=0
${v.text}
if (( _localstatus > 0 )); then
printf "Activation script snippet '%s' failed (%s)\n" "${a}" "$_localstatus"
fi
'';
});
path = with pkgs; map getBin
[ coreutils
gnugrep
findutils
getent
stdenv.cc.libc # nscd in update-users-groups.pl
shadow
nettools # needed for hostname
util-linux # needed for mount and mountpoint
];
scriptType = with types;
let scriptOptions =
{ deps = mkOption
{ type = types.listOf types.str;
default = [ ];
description = "List of dependencies. The script will run after these.";
};
text = mkOption
{ type = types.lines;
description = "The content of the script.";
};
};
in either str (submodule { options = scriptOptions; });
in
{
###### interface
options = {
system.activationScripts = mkOption {
default = {};
example = literalExample ''
{ stdio.text =
'''
# Needed by some programs.
ln -sfn /proc/self/fd /dev/fd
ln -sfn /proc/self/fd/0 /dev/stdin
ln -sfn /proc/self/fd/1 /dev/stdout
ln -sfn /proc/self/fd/2 /dev/stderr
''';
}
'';
description = ''
A set of shell script fragments that are executed when a NixOS
system configuration is activated. Examples are updating
/etc, creating accounts, and so on. Since these are executed
every time you boot the system or run
<command>nixos-rebuild</command>, it's important that they are
idempotent and fast.
'';
type = types.attrsOf scriptType;
apply = set: {
script =
''
#! ${pkgs.runtimeShell}
systemConfig=@out@
export PATH=/empty
for i in ${toString path}; do
PATH=$PATH:$i/bin:$i/sbin
done
_status=0
trap "_status=1 _localstatus=\$?" ERR
# Ensure a consistent umask.
umask 0022
${
let
set' = mapAttrs (n: v: if isString v then noDepEntry v else v) set;
withHeadlines = addAttributeName set';
in textClosureMap id (withHeadlines) (attrNames withHeadlines)
}
# Make this configuration the current configuration.
# The readlink is there to ensure that when $systemConfig = /system
# (which is a symlink to the store), /run/current-system is still
# used as a garbage collection root.
ln -sfn "$(readlink -f "$systemConfig")" /run/current-system
# Prevent the current configuration from being garbage-collected.
ln -sfn /run/current-system /nix/var/nix/gcroots/current-system
exit $_status
'';
};
};
system.userActivationScripts = mkOption {
default = {};
example = literalExample ''
{ plasmaSetup = {
text = '''
${pkgs.libsForQt5.kservice}/bin/kbuildsycoca5"
''';
deps = [];
};
}
'';
description = ''
A set of shell script fragments that are executed by a systemd user
service when a NixOS system configuration is activated. Examples are
rebuilding the .desktop file cache for showing applications in the menu.
Since these are executed every time you run
<command>nixos-rebuild</command>, it's important that they are
idempotent and fast.
'';
type = with types; attrsOf scriptType;
apply = set: {
script = ''
unset PATH
for i in ${toString path}; do
PATH=$PATH:$i/bin:$i/sbin
done
_status=0
trap "_status=1 _localstatus=\$?" ERR
${
let
set' = mapAttrs (n: v: if isString v then noDepEntry v else v) set;
withHeadlines = addAttributeName set';
in textClosureMap id (withHeadlines) (attrNames withHeadlines)
}
exit $_status
'';
};
};
environment.usrbinenv = mkOption {
default = "${pkgs.coreutils}/bin/env";
example = literalExample ''
"''${pkgs.busybox}/bin/env"
'';
type = types.nullOr types.path;
visible = false;
description = ''
The env(1) executable that is linked system-wide to
<literal>/usr/bin/env</literal>.
'';
};
};
###### implementation
config = {
system.activationScripts.stdio = ""; # obsolete
system.activationScripts.var =
''
# Various log/runtime directories.
mkdir -m 1777 -p /var/tmp
# Empty, immutable home directory of many system accounts.
mkdir -p /var/empty
# Make sure it's really empty
${pkgs.e2fsprogs}/bin/chattr -f -i /var/empty || true
find /var/empty -mindepth 1 -delete
chmod 0555 /var/empty
chown root:root /var/empty
${pkgs.e2fsprogs}/bin/chattr -f +i /var/empty || true
'';
system.activationScripts.usrbinenv = if config.environment.usrbinenv != null
then ''
mkdir -m 0755 -p /usr/bin
ln -sfn ${config.environment.usrbinenv} /usr/bin/.env.tmp
mv /usr/bin/.env.tmp /usr/bin/env # atomically replace /usr/bin/env
''
else ''
rm -f /usr/bin/env
rmdir --ignore-fail-on-non-empty /usr/bin /usr
'';
system.activationScripts.specialfs =
''
specialMount() {
local device="$1"
local mountPoint="$2"
local options="$3"
local fsType="$4"
if mountpoint -q "$mountPoint"; then
local options="remount,$options"
else
mkdir -m 0755 -p "$mountPoint"
fi
mount -t "$fsType" -o "$options" "$device" "$mountPoint"
}
source ${config.system.build.earlyMountScript}
'';
systemd.user = {
services.nixos-activation = {
description = "Run user-specific NixOS activation";
script = config.system.userActivationScripts.script;
unitConfig.ConditionUser = "!@system";
serviceConfig.Type = "oneshot";
};
};
};
}