nixos/samba, kdePackages.kdenetwork-filesharing: wire up usershares (#355031)

nixos/modules/services/network-filesystems/samba.nix

@@ -101,6 +101,19 @@ in
         };
       };
 
+      usershares = {
+        enable = lib.mkEnableOption "user-configurable Samba shares";
+        group = lib.mkOption {
+          type = lib.types.str;
+          default = "samba";
+          description = ''
+            Name of the group members of which will be allowed to create usershares.
+
+            The group will be created automatically.
+          '';
+        };
+      };
+
       nsswins = lib.mkEnableOption ''
         WINS NSS (Name Service Switch) plug-in.
 
@@ -308,5 +321,22 @@ in
           restartTriggers = [ configFile ];
         };
       })
+
+      (lib.mkIf (cfg.enable && cfg.usershares.enable) {
+        users.groups.${cfg.usershares.group} = {};
+
+        systemd.tmpfiles.settings."50-samba-usershares"."/var/lib/samba/usershares".d = {
+          user = "root";
+          group = cfg.usershares.group;
+          mode = "1775";  # sticky so users can't delete others' shares
+        };
+
+        # set some reasonable defaults
+        services.samba.settings.global = lib.mkDefault {
+          "usershare path" = "/var/lib/samba/usershares";
+          "usershare max shares" = 100;  # high enough to be considered ~unlimited
+          "usershare allow guests" = true;
+        };
+      })
     ];
 }

pkgs/kde/gear/kdenetwork-filesharing/default.nix

@@ -1,14 +1,34 @@
 {
+  lib,
   mkKdeDerivation,
+  substituteAll,
+  samba,
+  shadow,
   qtdeclarative,
 }:
 mkKdeDerivation {
   pname = "kdenetwork-filesharing";
 
-  patches = [ ./smbd-path.patch ];
+  patches = [
+    (substituteAll {
+      src = ./dependency-paths.patch;
+      inherit samba;
+      usermod = lib.getExe' shadow "usermod";
+    })
+
+    # Provide a better looking and more NixOS specific Samba hint
+    # Proposed upstream: https://invent.kde.org/network/kdenetwork-filesharing/-/merge_requests/56
+    ./samba-hint.patch
+  ];
 
   extraBuildInputs = [ qtdeclarative ];
 
   # We can't actually install samba via PackageKit, so let's not confuse users any more than we have to
   extraCmakeFlags = [ "-DSAMBA_INSTALL=OFF" ];
+
+  # Hardcoded as QStrings, which are UTF-16 so Nix can't pick these up automatically
+  postFixup = ''
+    mkdir -p $out/nix-support
+    echo "${samba} ${shadow}" > $out/nix-support/depends
+  '';
 }

pkgs/kde/gear/kdenetwork-filesharing/dependency-paths.patch

@@ -0,0 +1,71 @@
+diff --git a/samba/filepropertiesplugin/authhelper.cpp b/samba/filepropertiesplugin/authhelper.cpp
+index 6cbbd90..ae1d696 100644
+--- a/samba/filepropertiesplugin/authhelper.cpp
++++ b/samba/filepropertiesplugin/authhelper.cpp
+@@ -49,7 +49,7 @@ ActionReply AuthHelper::isuserknown(const QVariantMap &args)
+     }
+ 
+     QProcess p;
+-    const auto program = QStringLiteral("pdbedit");
++    const auto program = QStringLiteral("@samba@/bin/pdbedit");
+     const auto arguments = QStringList({QStringLiteral("--debuglevel=0"), QStringLiteral("--user"), username });
+     p.setProgram(program);
+     p.setArguments(arguments);
+@@ -88,7 +88,7 @@ ActionReply AuthHelper::createuser(const QVariantMap &args)
+     }
+ 
+     QProcess p;
+-    p.setProgram(QStringLiteral("smbpasswd"));
++    p.setProgram(QStringLiteral("@samba@/bin/smbpasswd"));
+     p.setArguments({
+         QStringLiteral("-L"), /* local mode */
+         QStringLiteral("-s"), /* read from stdin */
+@@ -152,7 +152,7 @@ ActionReply AuthHelper::addtogroup(const QVariantMap &args)
+         QStringLiteral("-m"),
+         QStringLiteral("{%1}").arg(user.value()) });
+ #elif defined(Q_OS_LINUX) || defined(Q_OS_HURD)
+-    p.setProgram(QStringLiteral("/usr/sbin/usermod"));
++    p.setProgram(QStringLiteral("@usermod@"));
+     p.setArguments({
+         QStringLiteral("--append"),
+         QStringLiteral("--groups"),
+diff --git a/samba/filepropertiesplugin/groupmanager.cpp b/samba/filepropertiesplugin/groupmanager.cpp
+index a2ba851..d54f6ce 100644
+--- a/samba/filepropertiesplugin/groupmanager.cpp
++++ b/samba/filepropertiesplugin/groupmanager.cpp
+@@ -18,7 +18,7 @@ GroupManager::GroupManager(QObject *parent)
+ {
+     metaObject()->invokeMethod(this, [this] {
+         auto proc = new QProcess;
+-        proc->setProgram(QStringLiteral("testparm"));
++        proc->setProgram(QStringLiteral("@samba@/bin/testparm"));
+         proc->setArguments({QStringLiteral("--debuglevel=0"),
+                             QStringLiteral("--suppress-prompt"),
+                             QStringLiteral("--verbose"),
+diff --git a/samba/filepropertiesplugin/sambausershareplugin.cpp b/samba/filepropertiesplugin/sambausershareplugin.cpp
+index 4f6642e..86ea121 100644
+--- a/samba/filepropertiesplugin/sambausershareplugin.cpp
++++ b/samba/filepropertiesplugin/sambausershareplugin.cpp
+@@ -112,7 +112,8 @@ SambaUserSharePlugin::SambaUserSharePlugin(QObject *parent)
+ bool SambaUserSharePlugin::isSambaInstalled()
+ {
+     return QFile::exists(QStringLiteral("/usr/sbin/smbd"))
+-        || QFile::exists(QStringLiteral("/usr/local/sbin/smbd"));
++        || QFile::exists(QStringLiteral("/usr/local/sbin/smbd"))
++        || QFile::exists(QStringLiteral("/run/current-system/sw/bin/smbd"));
+ }
+ 
+ void SambaUserSharePlugin::showSambaStatus()
+diff --git a/samba/filepropertiesplugin/usermanager.cpp b/samba/filepropertiesplugin/usermanager.cpp
+index 29238ce..ff20fcb 100644
+--- a/samba/filepropertiesplugin/usermanager.cpp
++++ b/samba/filepropertiesplugin/usermanager.cpp
+@@ -138,7 +138,7 @@ bool UserManager::canManageSamba() const
+ void UserManager::load()
+ {
+     auto proc = new QProcess(this);
+-    proc->setProgram(QStringLiteral("testparm"));
++    proc->setProgram(QStringLiteral("@samba@/bin/testparm"));
+     proc->setArguments({
+         QStringLiteral("--debuglevel=0"),
+         QStringLiteral("--suppress-prompt"),

pkgs/kde/gear/kdenetwork-filesharing/samba-hint.patch

@@ -0,0 +1,35 @@
+diff --git a/samba/filepropertiesplugin/qml/MissingSambaPage.qml b/samba/filepropertiesplugin/qml/MissingSambaPage.qml
+index 327c4a7..9e2eba7 100644
+--- a/samba/filepropertiesplugin/qml/MissingSambaPage.qml
++++ b/samba/filepropertiesplugin/qml/MissingSambaPage.qml
+@@ -6,20 +6,17 @@
+ import QtQuick 2.12
+ import QtQuick.Controls 2.5 as QQC2
+ import QtQuick.Layouts 1.14
+-import org.kde.kirigami 2.4 as Kirigami
+-import org.kde.filesharing.samba 1.0 as Samba
++import org.kde.kirigami as Kirigami
+ 
+ // When built without packagekit we cannot do auto-installation.
+-ColumnLayout {
+-    QQC2.Label {
+-        Layout.alignment: Qt.AlignHCenter
+-        Layout.fillWidth: true
+-        text: xi18nc("@info", "The <application>Samba</application> file sharing service must be installed before folders can be shared.")
+-        explanation: i18n("Because this distro does not include PackageKit, we cannot show you a nice \"Install it\" button, and you will have to use your package manager to install the <command>samba</command> server package manually.")
+-        wrapMode: Text.Wrap
+-    }
+-    Item {
+-        Layout.alignment: Qt.AlignHCenter
+-        Layout.fillHeight: true // space everything up
++Item {
++    Kirigami.PlaceholderMessage {
++        anchors.centerIn: parent
++        width: parent.width - (Kirigami.Units.largeSpacing * 4)
++
++        icon.name: "dialog-error"
++
++        text: xi18nc("@info", "File sharing service unavailable")
++        explanation: i18n("Please enable the `services.samba.enable` and `services.samba.usershares.enable` options in your NixOS configuration.")
+     }
+ }

pkgs/kde/gear/kdenetwork-filesharing/smbd-path.patch

@@ -1,14 +0,0 @@
-diff --git a/samba/filepropertiesplugin/sambausershareplugin.cpp b/samba/filepropertiesplugin/sambausershareplugin.cpp
-index d5c8d77..11c45d4 100644
---- a/samba/filepropertiesplugin/sambausershareplugin.cpp
-+++ b/samba/filepropertiesplugin/sambausershareplugin.cpp
-@@ -112,7 +112,8 @@ SambaUserSharePlugin::SambaUserSharePlugin(QObject *parent)
- bool SambaUserSharePlugin::isSambaInstalled()
- {
-     return QFile::exists(QStringLiteral("/usr/sbin/smbd"))
--        || QFile::exists(QStringLiteral("/usr/local/sbin/smbd"));
-+        || QFile::exists(QStringLiteral("/usr/local/sbin/smbd"))
-+        || QFile::exists(QStringLiteral("/run/current-system/sw/bin/smbd"));
- }
- 
- void SambaUserSharePlugin::showSambaStatus()