Add support for listing users in account services

app/src/main/cpp/skyline/services/account/IAccountServiceForApplication.cpp

@@ -1,6 +1,8 @@
 // SPDX-License-Identifier: MPL-2.0
 // Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
 
+#include <span>
+#include <kernel/types/KProcess.h>
 #include "IManagerForApplication.h"
 #include "IProfile.h"
 #include "IAccountServiceForApplication.h"
@@ -8,6 +10,8 @@
 namespace skyline::service::account {
     IAccountServiceForApplication::IAccountServiceForApplication(const DeviceState &state, ServiceManager &manager) : BaseService(state, manager, Service::account_IAccountServiceForApplication, "account:IAccountServiceForApplication", {
         {0x1, SFUNC(IAccountServiceForApplication::GetUserExistence)},
+        {0x2, SFUNC(IAccountServiceForApplication::ListAllUsers)},
+        {0x3, SFUNC(IAccountServiceForApplication::ListOpenUsers)},
         {0x4, SFUNC(IAccountServiceForApplication::GetLastOpenedUser)},
         {0x5, SFUNC(IAccountServiceForApplication::GetProfile)},
         {0x64, SFUNC(IAccountServiceForApplication::InitializeApplicationInfoV0)},
@@ -20,6 +24,28 @@ namespace skyline::service::account {
         response.Push<u32>(id == constant::DefaultUserId);
     }
 
+    void IAccountServiceForApplication::ListAllUsers(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
+        // We only support one active user currently so hardcode this and ListOpenUsers
+        WriteUserList(request.outputBuf.at(0), {constant::DefaultUserId});
+    }
+
+    void IAccountServiceForApplication::ListOpenUsers(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
+        WriteUserList(request.outputBuf.at(0), {constant::DefaultUserId});
+    }
+
+    void IAccountServiceForApplication::WriteUserList(ipc::OutputBuffer buffer, std::vector<UserId> userIds) {
+        std::span outputUserIds(state.process->GetPointer<UserId>(buffer.address), buffer.size / sizeof(UserId));
+
+        for (auto &userId : outputUserIds) {
+            if (userIds.empty()) {
+                userId = UserId{};
+            } else {
+                userId = userIds.back();
+                userIds.pop_back();
+            }
+        }
+    }
+
     void IAccountServiceForApplication::GetLastOpenedUser(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response) {
         response.Push(constant::DefaultUserId);
     }

app/src/main/cpp/skyline/services/account/IAccountServiceForApplication.h

@@ -27,6 +27,12 @@ namespace skyline {
         * @brief IAccountServiceForApplication or acc:u0 provides functions for reading user information (https://switchbrew.org/wiki/Account_services#acc:u0)
         */
         class IAccountServiceForApplication : public BaseService {
+          private:
+            /**
+             * @brief Writes a vector of 128-bit user IDs to an output buffer
+             */
+            void WriteUserList(ipc::OutputBuffer buffer, std::vector<UserId> userIds);
+
           public:
             IAccountServiceForApplication(const DeviceState &state, ServiceManager &manager);
 
@@ -35,6 +41,16 @@ namespace skyline {
             */
             void GetUserExistence(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response);
 
+            /**
+            * @brief This returns a list of all user accounts on the console
+            */
+            void ListAllUsers(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response);
+
+            /**
+            * @brief This returns a list of all open user accounts on the console
+            */
+            void ListOpenUsers(type::KSession &session, ipc::IpcRequest &request, ipc::IpcResponse &response);
+
             /**
             * @brief This returns the user ID of the last active user on the console
             */