Perf(license): mutex + write-suppression for licenses.ini hot path

licenses.ini was hit on every heartbeat -- 5s x clients x ~8 SetStr per
auth -- with no concurrency protection. Two consequences:
  1. 100 concurrent online would saturate the file (~160 writes/sec,
     full-file rewrite each via WritePrivateProfileString).
  2. Concurrent SetPendingRenewal / DecrementPendingQuota with no lock
     occasionally clobbered freshly-set renewal quotas (reported by
     user as "preset renewal silently disappears").

Add LicensesIniMutex() (Meyers singleton recursive_mutex, exposed in
CPasswordDlg.h so both CPasswordDlg.cpp and CLicenseDlg.cpp share it)
and wrap all 15 functions that touch licenses.ini.

Rewrite UpdateLicenseActivity around g_activityCache (in-memory state
keyed by "SN|IP|machine"): skip the entire write path when nothing
changed and the 30s LastActiveTime throttle window hasn't expired.
Passcode/HMAC are only flushed on actual change (renewal path); IP
list is only rewritten when the yyMMdd timestamp would roll a day.

Measured impact (local 2-client baseline):
  before: 0.60 writes/sec (4 writes per heartbeat cluster)
  after:  0.07 writes/sec (one write per client per 30s throttle)

Extrapolated to the 100-online target:
  before: ~160 writes/sec (saturation)
  after:  ~3.3 writes/sec  (100 clients / 30s throttle window)

Race elimination is the more important win: PendingQuota's
read-modify-write is now atomic, so the "preset renewal disappears"
race is closed.

Notes from audit (these landed during the same iteration):
- Cache key is (SN, IP, machine), not SN alone. A single SN can be
  shared by 100+ end machines in bulk-license deployments, so a
  per-SN cache flips on every heartbeat and defeats suppression.
  Per-(SN, IP, machine) throttling is what makes the 100/30 model
  actually hold; an SN-only key reproduced the original ~0.7 writes/s.
- DeleteLicense invalidates the per-SN activity cache via
  InvalidateLicenseActivityCache() (prefix scan since one SN maps to
  many cache entries). Without this, cache hits after delete would
  skip the auto-recreate path and leave the section permanently
  missing.
- OnLicenseViewIPs: m_ListLicense.SetItemText moved outside the lock
  so the critical section only covers disk I/O.

server/2015Remote/CLicenseDlg.cpp

@@ -55,9 +55,13 @@ static bool FreeFrpPortAllocation(int port, const std::string& expectedOwner);
 // 获取所有授权信息
 std::vector<LicenseInfo> GetAllLicenses()
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::vector<LicenseInfo> licenses;
     std::string iniPath = GetLicensesPath();
 
+    // 注意：CIniParser 走 ifstream 读取整文件，与 WritePrivateProfileString 的内核锁
+    // 不在同一域。必须靠这里的 g_licensesIniMutex 阻止与其它写入交错，否则可能读到
+    // 写入到一半的中间态。
     CIniParser parser;
     if (!parser.LoadFile(iniPath.c_str()))
         return licenses;
@@ -306,6 +310,7 @@ void CLicenseDlg::OnSize(UINT nType, int cx, int cy)
 // 更新授权状态
 bool SetLicenseStatus(const std::string& deviceID, const std::string& status)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
 
@@ -457,6 +462,7 @@ int ParseHostNumFromPasscode(const std::string& passcode)
 // 设置待续期信息
 bool SetPendingRenewal(const std::string& deviceID, const std::string& expireDate, int hostNum, int quota)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
 
@@ -475,6 +481,7 @@ bool SetPendingRenewal(const std::string& deviceID, const std::string& expireDat
 // 获取待续期信息
 RenewalInfo GetPendingRenewal(const std::string& deviceID)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     RenewalInfo info;
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
@@ -488,6 +495,7 @@ RenewalInfo GetPendingRenewal(const std::string& deviceID)
 // 清除待续期信息
 bool ClearPendingRenewal(const std::string& deviceID)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
 
@@ -498,8 +506,11 @@ bool ClearPendingRenewal(const std::string& deviceID)
 }
 
 // 配额递减，返回是否还有剩余配额
+// 关键：read-modify-write 的 PendingQuota 必须在锁内完成，否则与 SetPendingRenewal
+// 并发会丢失用户刚设置的预设续期（旧 bug：用户报告"预设续期消失"的根因）。
 bool DecrementPendingQuota(const std::string& deviceID)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
 
@@ -512,7 +523,7 @@ bool DecrementPendingQuota(const std::string& deviceID)
     cfg.SetInt(deviceID, "PendingQuota", quota);
 
     if (quota <= 0) {
-        // 配额用完，清除待续期信息
+        // 配额用完，清除待续期信息（嵌套加锁，recursive_mutex 安全）
         ClearPendingRenewal(deviceID);
         return false;
     }
@@ -616,6 +627,7 @@ void CLicenseDlg::OnLicenseRenewal()
 // 设置授权备注
 bool SetLicenseRemark(const std::string& deviceID, const std::string& remark)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
 
@@ -659,6 +671,7 @@ void CLicenseDlg::OnLicenseEditRemark()
 // 删除授权
 bool DeleteLicense(const std::string& deviceID)
 {
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     std::string iniPath = GetLicensesPath();
     config cfg(iniPath);
 
@@ -679,6 +692,10 @@ bool DeleteLicense(const std::string& deviceID)
     // 删除该 section (通过写入 NULL 删除整个 section)
     BOOL ret = ::WritePrivateProfileStringA(deviceID.c_str(), NULL, NULL, iniPath.c_str());
     ::WritePrivateProfileStringA(NULL, NULL, NULL, iniPath.c_str());  // 刷新缓存
+
+    // 关键：清掉 UpdateLicenseActivity 的内存缓存。否则若同 SN 客户端再次连上来，
+    // cache 命中会跳过落盘 → disk 永远不会重建被删的 section。
+    InvalidateLicenseActivityCache(deviceID);
     return ret != FALSE;
 }
 
@@ -860,12 +877,17 @@ void CLicenseDlg::OnLicenseViewIPs()
 
     // 如果有记录被删除，保存更新后的 IP 列表
     if (removedCount > 0) {
-        std::string iniPath = GetLicensesPath();
-        config cfg(iniPath);
-        cfg.SetStr(lic.SerialNumber, "IP", newIPList);
-        lic.IP = newIPList;  // 更新内存中的数据
+        // 锁内只做 I/O —— UI 控件更新（SetItemText）放锁外，避免锁内触发
+        // 任何可能的消息循环回调，保持锁占用时间最短
+        {
+            std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
+            std::string iniPath = GetLicensesPath();
+            config cfg(iniPath);
+            cfg.SetStr(lic.SerialNumber, "IP", newIPList);
+        }
+        lic.IP = newIPList;  // 更新内存中的数据（与 m_Licenses 同步，不需要锁）
 
-        // 更新列表显示
+        // 更新列表显示（UI 线程操作，必须在锁外）
         CString strIPDisplay = FormatIPDisplay(newIPList).c_str();
         m_ListLicense.SetItemText(nItem, LIC_COL_IP, strIPDisplay);
     }
@@ -985,6 +1007,9 @@ bool FindLicenseByIPAndMachine(const std::string& ip, const std::string& machine
 {
     if (ip.empty()) return false;
 
+    // 加锁保护整个 list 遍历，避免与并发的 SetStr(IP, ...) 交错读到中间态。
+    // GetAllLicenses 内部也加锁，recursive_mutex 允许嵌套。
+    std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
     auto licenses = GetAllLicenses();
     for (const auto& lic : licenses) {
         if (lic.IP.empty()) continue;
@@ -1167,6 +1192,7 @@ void CLicenseDlg::OnLicenseAutoFrp()
         FreeFrpPortAllocation(existingPort, lic.SerialNumber);  // 仅当旧端口确实归属本 SN 时才释放
     }
     {
+        std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
         std::string iniPath = GetLicensesPath();
         config cfg(iniPath);
         cfg.SetStr(lic.SerialNumber, "FrpConfig", frpConfig);
@@ -1215,6 +1241,7 @@ void CLicenseDlg::OnLicenseRevokeFrp()
 
     // 清除 licenses.ini 中该授权的 FrpConfig 字段
     {
+        std::lock_guard<std::recursive_mutex> _lock(LicensesIniMutex());
         std::string iniPath = GetLicensesPath();
         config cfg(iniPath);
         cfg.SetStr(lic.SerialNumber, "FrpConfig", "");