add store root for nixos install

Cargo.toml

@@ -15,6 +15,7 @@ clap = "3.0.0-beta.2"
 flexi_logger = "0.16"
 fork = "0.1"
 futures-util = "0.3.6"
+linked_hash_set = "0.1.4"
 log = "0.4"
 merge = "0.1.0"
 notify = "5.0.0-pre.3"

chroot-wrapper.bash

@@ -0,0 +1,44 @@
+set -e
+
+# Re-exec ourselves in a private mount namespace so that our bind
+# mounts get cleaned up automatically.
+if [ -z "$NIXOS_ENTER_REEXEC" ]; then
+    export NIXOS_ENTER_REEXEC=1
+    if [ "$(id -u)" != 0 ]; then
+        extraFlags="-r"
+    fi
+    exec unshare --fork --mount --uts --mount-proc --pid $extraFlags -- "$0" "$@"
+else
+    mount --make-rprivate /
+fi
+
+mountPoint=/mnt
+
+while [ "$#" -gt 0 ]; do
+    i="$1"; shift 1
+    case "$i" in
+        --root)
+            mountPoint="$1"; shift 1
+            ;;
+        --)
+            command=("$@")
+            break
+            ;;
+        *)
+            echo "$0: unknown option \`$i'"
+            exit 1
+            ;;
+    esac
+done
+
+mkdir -p "$mountPoint/dev" "$mountPoint/sys" "$mountPoint/tmp" "$mountPoint/etc" "$mountPoint/proc"
+chmod 0755 "$mountPoint/dev" "$mountPoint/sys" "$mountPoint/tmp" "$mountPoint/etc" "$mountPoint/proc"
+mount --rbind /dev "$mountPoint/dev"
+mount --rbind /sys "$mountPoint/sys"
+mount --rbind /proc "$mountPoint/proc"
+
+touch "$mountPoint/etc/mtab" || true # might be already a working system
+(cd "$mountPoint" && ln -snf "../proc/self/mounts" "etc/mtab") # Grub needs an mtab.
+
+export CHROOTED=1
+exec chroot "$mountPoint" "${command[@]}"

flake.nix

@@ -70,10 +70,22 @@
                           executable = true;
                           destination = "/deploy-rs-activate";
                         })
+                        (final.writeTextFile  {
+                          name = base.name + "-activate-chroot-wrapper";
+                          text = ''
+                          # no interpreter: absolute storepaths are not resolvable outside chroot
+                          # run with bash <>, instead
+                          ${nixpkgs.lib.fileContents ./chroot-wrapper.bash};
+                          '';
+                          executable = true;
+                          destination = "/deploy-rs-chroot-wrapper";
+                        })
                         (final.writeTextFile {
                             name = base.name + "-activate-rs";
                             text = ''
                             #!${final.runtimeShell}
+                            # required by bin/activate
+                            export PATH="${nixpkgs.lib.makeBinPath [final.nixUnstable final.coreutils]}"
                             exec ${self.defaultPackage.${system}}/bin/activate "$@"
                           '';
                           executable = true;
@@ -84,15 +96,49 @@
               };
 
             nixos = base: (custom // { dryActivate = "$PROFILE/bin/switch-to-configuration dry-activate"; }) base.config.system.build.toplevel ''
+              export PATH="${nixpkgs.lib.makeBinPath [final.coreutils]}"
               # work around https://github.com/NixOS/nixpkgs/issues/73404
               cd /tmp
 
-              $PROFILE/bin/switch-to-configuration switch
+              _SYSTEM="/nix/var/nix/profiles/system"
+              _SWITCH_COMMAND="$PROFILE/bin/switch-to-configuration"
+
+              # Set $LOCALE_ARCHIVE to supress some Perl locale warnings.
+              export LOCALE_ARCHIVE="$PROFILE/sw/lib/locale/locale-archive"
+
+              _already_on_nixos() { [[ -f "/etc/NIXOS" ]]; }
+              _switch_cmd() {
+                  "$_SWITCH_COMMAND" "$1"
+              }
+
+              _become_a_nixos() { touch /etc/NIXOS; }
+              _if_chrooted() { [[ "''${CHROOTED:-}" == "1" ]] && echo $@; }
+              _activate_system() {
+                  # Run the activation script.
+                  "$PROFILE/activate" 1>&2 || true
+                  # Cooperatively respect our chrooted environment
+                  ${final.systemd}/bin/systemd-tmpfiles --create --remove $(_if_chrooted "--exclude-prefix=/dev") 1>&2 || true;
+              }
+
+              if _already_on_nixos
+              then
+                  _switch_cmd switch
+              else
+                  echo "-> Become a NixOS ..."
+                  _become_a_nixos
+                  echo "-> Activate the system ..."
+                  _activate_system
+                  echo "-> Install the boot loader ..."
+                  NIXOS_INSTALL_BOOTLOADER=1 _switch_cmd boot
+                  echo "-> Reboot ..."
+                  $(_if_chrooted sync && echo b |tee /proc/sysrq-trigger)
+                  ${final.systemd}/bin/reboot --reboot
+              fi
 
               # https://github.com/serokell/deploy-rs/issues/31
               ${with base.config.boot.loader;
               final.lib.optionalString systemd-boot.enable
-              "sed -i '/^default /d' ${efi.efiSysMountPoint}/loader/loader.conf"}
+              "${final.gnused}/bin/sed -i '/^default /d' ${efi.efiSysMountPoint}/loader/loader.conf"}
             '';
 
             home-manager = base: custom base.activationPackage "$PROFILE/activate";