nixos-rebuild: Exec nixos-rebuild from the new Nixpkgs tree

This allows doing any necessary actions that were not in the installed
nixos-rebuild (such as downloading a new version of Nix). This does
require us to be careful that nixos-rebuild is backwards-compatible
(i.e. can run in any old installation).
This commit is contained in:
Eelco Dolstra 2014-04-15 11:47:41 +02:00
parent 35bf0f4810
commit f9e6181478

View file

@ -1,4 +1,6 @@
#! @shell@ -e
#! @shell@
set -e
showSyntax() {
exec man nixos-rebuild
@ -7,6 +9,7 @@ showSyntax() {
# Parse the command line.
origArgs=("$@")
extraBuildFlags=()
action=
buildNix=1
@ -76,8 +79,30 @@ done
if [ -z "$action" ]; then showSyntax; fi
if [ -n "$rollback" ]; then
buildNix=
# Only run shell scripts from the Nixpkgs tree if the action is
# "switch", "boot", or "test". With other actions (such as "build"),
# the user may reasonably expect that no code from the Nixpkgs tree is
# executed, so it's safe to run nixos-rebuild against a potentially
# untrusted tree.
canRun=
if [ "$action" = switch -o "$action" = boot -o "$action" = test ]; then
canRun=1
fi
# If --upgrade is given, run nix-channel --update nixos.
if [ -n "$upgrade" -a -z "$_NIXOS_REBUILD_REEXEC" ]; then
nix-channel --update nixos
fi
# Re-execute nixos-rebuild from the Nixpkgs tree.
if [ -z "$_NIXOS_REBUILD_REEXEC" -a -n "$canRun" ]; then
if p=$(nix-instantiate --find-file nixpkgs/nixos/modules/installer/tools/nixos-rebuild.sh "${extraBuildFlags[@]}"); then
export _NIXOS_REBUILD_REEXEC=1
exec $SHELL -e $p "${origArgs[@]}"
exit 1
fi
fi
@ -98,16 +123,14 @@ if [ -z "$repair" ] && systemctl show nix-daemon.socket nix-daemon.service | gre
fi
# If --upgrade is given, run nix-channel --update nixos.
if [ -n "$upgrade" ]; then
nix-channel --update nixos
fi
# First build Nix, since NixOS may require a newer version than the
# current one. Of course, the same goes for Nixpkgs, but Nixpkgs is
# more conservative.
if [ "$action" != dry-run -a -n "$buildNix" ]; then
if [ -n "$rollback" -o "$action" = dry-run ]; then
buildNix=
fi
if [ -n "$buildNix" ]; then
echo "building Nix..." >&2
if ! nix-build '<nixpkgs/nixos>' -A config.nix.package -o $tmpDir/nix "${extraBuildFlags[@]}" > /dev/null; then
if ! nix-build '<nixpkgs/nixos>' -A nixFallback -o $tmpDir/nix "${extraBuildFlags[@]}" > /dev/null; then
@ -120,10 +143,12 @@ fi
# Update the version suffix if we're building from Git (so that
# nixos-version shows something useful).
if nixpkgs=$(nix-instantiate --find-file nixpkgs "${extraBuildFlags[@]}"); then
suffix=$(@shell@ $nixpkgs/nixos/modules/installer/tools/get-version-suffix "${extraBuildFlags[@]}" || true)
if [ -n "$suffix" ]; then
echo -n "$suffix" > "$nixpkgs/.version-suffix" || true
if [ -n "$canRun" ]; then
if nixpkgs=$(nix-instantiate --find-file nixpkgs "${extraBuildFlags[@]}"); then
suffix=$($SHELL $nixpkgs/nixos/modules/installer/tools/get-version-suffix "${extraBuildFlags[@]}" || true)
if [ -n "$suffix" ]; then
echo -n "$suffix" > "$nixpkgs/.version-suffix" || true
fi
fi
fi