fhs-userenv-bubblewrap: change to using bubblewrap over chrootenv

pkgs/build-support/build-fhs-userenv-bubblewrap/default.nix

@@ -1,36 +1,70 @@
-{ callPackage, runCommandLocal, writeScript, stdenv, coreutils }:
+{ callPackage, runCommandLocal, writeShellScriptBin, stdenv, coreutils, bubblewrap }:
 
 let buildFHSEnv = callPackage ./env.nix { }; in
 
-args@{ name, runScript ? "bash", extraInstallCommands ? "", meta ? {}, passthru ? {}, ... }:
+args @ {
+  name,
+  runScript ? "bash",
+  extraInstallCommands ? "",
+  meta ? {},
+  passthru ? {},
+  ...
+}:
 
+with builtins;
 let
-  env = buildFHSEnv (removeAttrs args [ "runScript" "extraInstallCommands" "meta" "passthru" ]);
+  env = buildFHSEnv (removeAttrs args [
+    "runScript" "extraInstallCommands" "meta" "passthru"
+  ]);
 
   chrootenv = callPackage ./chrootenv {};
 
-  init = run: writeScript "${name}-init" ''
-    #! ${stdenv.shell}
-    for i in ${env}/* /host/*; do
-      path="/''${i##*/}"
-      [ -e "$path" ] || ${coreutils}/bin/ln -s "$i" "$path"
-    done
-
-    [ -d "$1" ] && [ -r "$1" ] && cd "$1"
-    shift
-
+  init = run: writeShellScriptBin "${name}-init" ''
     source /etc/profile
     exec ${run} "$@"
   '';
 
+  bwrap_cmd = { init_args ? "" }: ''
+    blacklist="/nix /dev /proc"
+    ro_mounts=""
+    for i in ${env}/*; do
+      path="/''${i##*/}"
+      ro_mounts="$ro_mounts --ro-bind $i $path"
+      blacklist="$blacklist $path"
+    done
+
+    auto_mounts=""
+    # loop through all directories in the root
+    for dir in /*; do
+      # if it is a directory and it is not in the blacklist
+      if [[ -d "$dir" ]] && grep -v "$dir" <<< "$blacklist" >/dev/null; then
+        # add it to the mount list
+        auto_mounts="$auto_mounts --bind $dir $dir"
+      fi
+    done
+
+    exec ${bubblewrap}/bin/bwrap \
+      --dev /dev \
+      --proc /proc \
+      --chdir "$(pwd)" \
+      --unshare-all \
+      --share-net \
+      --die-with-parent \
+      --ro-bind /nix /nix \
+      --ro-bind /etc /host-etc \
+      $ro_mounts \
+      $auto_mounts \
+      ${init runScript}/bin/${name}-init ${init_args}
+  '';
+
+  bin = writeShellScriptBin name (bwrap_cmd { init_args = ''"$@"''; });
+
 in runCommandLocal name {
   inherit meta;
 
   passthru = passthru // {
     env = runCommandLocal "${name}-shell-env" {
-      shellHook = ''
-        exec ${chrootenv}/bin/chrootenv ${init runScript} "$(pwd)"
-      '';
+      shellHook = bwrap_cmd {};
     } ''
       echo >&2 ""
       echo >&2 "*** User chroot 'env' attributes are intended for interactive nix-shell sessions, not for building! ***"
@@ -40,10 +74,6 @@ in runCommandLocal name {
   };
 } ''
   mkdir -p $out/bin
-  cat <<EOF >$out/bin/${name}
-  #! ${stdenv.shell}
-  exec ${chrootenv}/bin/chrootenv ${init runScript} "\$(pwd)" "\$@"
-  EOF
-  chmod +x $out/bin/${name}
+  ln -s ${bin}/bin/${name} $out/bin/${name}
   ${extraInstallCommands}
 ''

pkgs/build-support/build-fhs-userenv-bubblewrap/env.nix

@@ -79,39 +79,42 @@ let
       ln -s ${etcProfile} profile
 
       # compatibility with NixOS
-      ln -s /host/etc/static static
+      ln -s /host-etc/static static
 
       # symlink some NSS stuff
-      ln -s /host/etc/passwd passwd
-      ln -s /host/etc/group group
-      ln -s /host/etc/shadow shadow
-      ln -s /host/etc/hosts hosts
-      ln -s /host/etc/resolv.conf resolv.conf
-      ln -s /host/etc/nsswitch.conf nsswitch.conf
+      ln -s /host-etc/passwd passwd
+      ln -s /host-etc/group group
+      ln -s /host-etc/shadow shadow
+      ln -s /host-etc/hosts hosts
+      ln -s /host-etc/resolv.conf resolv.conf
+      ln -s /host-etc/nsswitch.conf nsswitch.conf
 
       # symlink sudo and su stuff
-      ln -s /host/etc/login.defs login.defs
-      ln -s /host/etc/sudoers sudoers
-      ln -s /host/etc/sudoers.d sudoers.d
+      ln -s /host-etc/login.defs login.defs
+      ln -s /host-etc/sudoers sudoers
+      ln -s /host-etc/sudoers.d sudoers.d
 
       # symlink other core stuff
-      ln -s /host/etc/localtime localtime
-      ln -s /host/etc/zoneinfo zoneinfo
-      ln -s /host/etc/machine-id machine-id
-      ln -s /host/etc/os-release os-release
+      ln -s /host-etc/localtime localtime
+      ln -s /host-etc/zoneinfo zoneinfo
+      ln -s /host-etc/machine-id machine-id
+      ln -s /host-etc/os-release os-release
 
       # symlink PAM stuff
-      ln -s /host/etc/pam.d pam.d
+      ln -s /host-etc/pam.d pam.d
 
       # symlink fonts stuff
-      ln -s /host/etc/fonts fonts
+      ln -s /host-etc/fonts fonts
 
       # symlink ALSA stuff
-      ln -s /host/etc/asound.conf asound.conf
+      ln -s /host-etc/asound.conf asound.conf
 
       # symlink SSL certs
       mkdir -p ssl
-      ln -s /host/etc/ssl/certs ssl/certs
+      ln -s /host-etc/ssl/certs ssl/certs
+
+      # Fedora stores certs in another directory
+      ln -s /host-etc/pki pki
 
       # symlink /etc/mtab -> /proc/mounts (compat for old userspace progs)
       ln -s /proc/mounts mtab