apptainer, singularity: add argument systemBinPaths

Use systemBinPaths as the new way to specify system bin paths,
especifally for SUID'ed binaries.

Deprecate arguments setuidmapPath and setgidmapPath in favour of
systemBinPaths.

Add NixOS configuration option programs.singularity.systemBinPath, with
"/run/wrappers/bin" included by default.

nixos/modules/programs/singularity.nix

@@ -56,9 +56,12 @@ in
     enableFakeroot = lib.mkOption {
       type = lib.types.bool;
       default = true;
-      example = false;
       description = ''
         Whether to enable the `--fakeroot` support of Singularity/Apptainer.
+
+        This option is deprecated and has no effect.
+        `--fakeroot` support is enabled automatically,
+        as `systemBinPaths = [ "/run/wrappers/bin" ]` is always specified.
       '';
     };
     enableSuid = lib.mkOption {
@@ -74,22 +77,34 @@ in
         Whether to enable the SUID support of Singularity/Apptainer.
       '';
     };
+    systemBinPaths = lib.mkOption {
+      type = lib.types.listOf lib.types.path;
+      default = [ ];
+      description = ''
+        (Extra) system-wide /**/bin paths
+        for Apptainer/Singularity to find command-line utilities in.
+
+        `"/run/wrappers/bin"` is included by default to make
+        utilities with SUID bit set available to Apptainer/Singularity.
+        Use `lib.mkForce` to shadow the default values.
+      '';
+    };
   };
 
   config = lib.mkIf cfg.enable {
     programs.singularity.packageOverriden = (
       cfg.package.override (
-        lib.optionalAttrs cfg.enableExternalLocalStateDir { externalLocalStateDir = "/var/lib"; }
-        // lib.optionalAttrs cfg.enableFakeroot {
-          newuidmapPath = "/run/wrappers/bin/newuidmap";
-          newgidmapPath = "/run/wrappers/bin/newgidmap";
+        {
+          systemBinPaths = cfg.systemBinPaths;
         }
+        // lib.optionalAttrs cfg.enableExternalLocalStateDir { externalLocalStateDir = "/var/lib"; }
         // lib.optionalAttrs cfg.enableSuid {
           enableSuid = true;
           starterSuidPath = "/run/wrappers/bin/${cfg.package.projectName}-suid";
         }
       )
     );
+    programs.singularity.systemBinPaths = [ "/run/wrappers/bin" ];
     environment.systemPackages = [ cfg.packageOverriden ];
     security.wrappers."${cfg.packageOverriden.projectName}-suid" = lib.mkIf cfg.enableSuid {
       setuid = true;

pkgs/applications/virtualization/singularity/generic.nix

@@ -70,11 +70,19 @@ in
   # Whether to compile with SUID support
   enableSuid ? false,
   starterSuidPath ? null,
-  # newuidmapPath and newgidmapPath are to support --fakeroot
-  # where those SUID-ed executables are unavailable from the FHS system PATH.
+  # Extra system-wide /**/bin paths to prefix,
+  # useful to specify directories containing binaries with SUID bit set.
+  # The paths take higher precedence over the FHS system PATH specified
+  # inside the upstream source code.
+  # Include "/run/wrappers/bin" by default for the convenience of NixOS users.
+  systemBinPaths ? [ "/run/wrappers/bin" ],
   # Path to SUID-ed newuidmap executable
+  # Deprecated in favour of systemBinPaths
+  # TODO(@ShamrockLee): Remove after Nixpkgs 24.05 branch-off
   newuidmapPath ? null,
   # Path to SUID-ed newgidmap executable
+  # Deprecated in favour of systemBinPaths
+  # TODO(@ShamrockLee): Remove after Nixpkgs 24.05 branch-off
   newgidmapPath ? null,
   # External LOCALSTATEDIR
   externalLocalStateDir ? null,
@@ -99,18 +107,26 @@ in
   vendorHash ? _defaultGoVendorArgs.vendorHash,
   deleteVendor ? _defaultGoVendorArgs.deleteVendor,
   proxyVendor ? _defaultGoVendorArgs.proxyVendor,
-}:
+}@args:
 
 let
+  # Backward compatibility for privileged-un-utils.
+  # TODO(@ShamrockLee): Remove after Nixpkgs 24.05 branch-off.
   privileged-un-utils =
     if ((newuidmapPath == null) && (newgidmapPath == null)) then
       null
     else
-      (runCommandLocal "privileged-un-utils" { } ''
+      runCommandLocal "privileged-un-utils" { } ''
         mkdir -p "$out/bin"
         ln -s ${lib.escapeShellArg newuidmapPath} "$out/bin/newuidmap"
         ln -s ${lib.escapeShellArg newgidmapPath} "$out/bin/newgidmap"
-      '');
+      '';
+
+  # Backward compatibility for privileged-un-utils.
+  # TODO(@ShamrockLee): Remove after Nixpkgs 24.05 branch-off.
+  systemBinPaths =
+    lib.optional (privileged-un-utils != null) (lib.makeBinPath [ privileged-un-utils ])
+    ++ args.systemBinPaths or [ "/run/wrappers/bin" ];
 
   concatMapStringAttrsSep =
     sep: f: attrs:
@@ -207,7 +223,6 @@ in
     fuse2fs # Mount ext3 filesystems
     go
     mount # mount
-    privileged-un-utils
     squashfsTools # mksquashfs unsquashfs # Make / unpack squashfs image
     squashfuse # squashfuse_ll squashfuse # Mount (without unpacking) a squashfs image without privileges
   ] ++ lib.optional enableNvidiaContainerCli nvidia-docker;
@@ -229,7 +244,7 @@ in
             lib.concatStringsSep " " [
               "--replace-fail"
               (addShellDoubleQuotes (lib.escapeShellArg originalDefaultPath))
-              (addShellDoubleQuotes ''${lib.escapeShellArg originalDefaultPath}''${inputsDefaultPath:+:}$inputsDefaultPath'')
+              (addShellDoubleQuotes ''$systemDefaultPath''${systemDefaultPath:+:}${lib.escapeShellArg originalDefaultPath}''${inputsDefaultPath:+:}$inputsDefaultPath'')
             ]
           ) originalDefaultPaths
         }
@@ -271,6 +286,7 @@ in
     # Respect PATH from the environment/the user.
     # Fallback to bin paths provided by Nixpkgs packages.
     wrapProgram "$out/bin/${projectName}" \
+      --suffix PATH : "$systemDefaultPath" \
       --suffix PATH : "$inputsDefaultPath"
     # Make changes in the config file
     ${lib.optionalString forceNvcCli ''
@@ -329,6 +345,7 @@ in
 }).overrideAttrs
   (
     finalAttrs: prevAttrs: {
+      systemDefaultPath = lib.concatStringsSep ":" systemBinPaths;
       inputsDefaultPath = lib.makeBinPath finalAttrs.defaultPathInputs;
       passthru = prevAttrs.passthru or { } // {
         inherit sourceFilesWithDefaultPaths;