Make conversions between std::chrono time_point and string safer by not using "localtime" directly.

apps/mwiniimporter/importer.cpp

@@ -639,14 +639,13 @@ std::time_t MwIniImporter::lastWriteTime(const std::filesystem::path& filename,
     if (std::filesystem::exists(filename))
     {
         std::filesystem::path resolved = std::filesystem::canonical(filename);
-        writeTime = Misc::to_time_t(std::filesystem::last_write_time(resolved));
+        const auto time = std::filesystem::last_write_time(resolved);
+        writeTime = Misc::toTimeT(time);
 
         // print timestamp
-        const int size = 1024;
+        const auto str = Misc::fileTimeToString(time, "%x %X");
-        char timeStrBuffer[size];
+        if (!str.empty())
-        if (std::strftime(timeStrBuffer, size, "%x %X", localtime(&writeTime)) > 0)
+            std::cout << "content file: " << resolved << " timestamp = (" << writeTime << ") " << str << std::endl;
-            std::cout << "content file: " << resolved << " timestamp = (" << writeTime << ") " << timeStrBuffer
-                      << std::endl;
     }
     return writeTime;
 }

apps/opencs/view/doc/view.cpp

@@ -30,6 +30,7 @@
 
 #include <components/files/conversion.hpp>
 #include <components/misc/helpviewer.hpp>
+#include <components/misc/timeconvert.hpp>
 #include <components/version/version.hpp>
 
 #include "globaldebugprofilemenu.hpp"
@@ -765,11 +766,7 @@ void CSVDoc::View::infoAbout()
 #endif
 
     // Get current year
-    time_t now = time(nullptr);
+    const auto copyrightInfo = Misc::timeToString(std::chrono::system_clock::now(), "Copyright © 2008-%Y OpenMW Team");
-    struct tm tstruct;
-    char copyrightInfo[40];
-    tstruct = *localtime(&now);
-    strftime(copyrightInfo, sizeof(copyrightInfo), "Copyright © 2008-%Y OpenMW Team", &tstruct);
 
     QString aboutText = QString(
         "<p style=\"white-space: pre-wrap;\">"
@@ -788,7 +785,8 @@ void CSVDoc::View::infoAbout()
                             .arg(versionInfo,
                                 tr("OpenMW-CS is a content file editor for OpenMW, a modern, free and open source game "
                                    "engine."),
-                                tr(copyrightInfo), tr("Home Page:"), tr("Forum:"), tr("Bug Tracker:"), tr("IRC:"));
+                                tr(copyrightInfo.c_str()), tr("Home Page:"), tr("Forum:"), tr("Bug Tracker:"),
+                                tr("IRC:"));
 
     QMessageBox::about(this, "About OpenMW-CS", aboutText);
 }

apps/openmw/mwgui/savegamedialog.cpp

@@ -410,11 +410,8 @@ namespace MWGui
             throw std::runtime_error("Can't find selected slot");
 
         std::stringstream text;
-        time_t time = Misc::to_time_t(mCurrentSlot->mTimeStamp);
-        struct tm* timeinfo;
-        timeinfo = localtime(&time);
 
-        text << std::put_time(timeinfo, "%Y.%m.%d %T") << "\n";
+        text << Misc::fileTimeToString(mCurrentSlot->mTimeStamp, "%Y.%m.%d %T") << "\n";
 
         text << "#{sLevel} " << mCurrentSlot->mProfile.mPlayerLevel << "\n";
         text << "#{sCell=" << mCurrentSlot->mProfile.mPlayerCell << "}\n";

components/config/launchersettings.cpp

@@ -223,18 +223,20 @@ bool Config::LauncherSettings::isEqual(const QStringList& list1, const QStringLi
 QString Config::LauncherSettings::makeNewContentListName()
 {
     // basically, use date and time as the name  e.g. YYYY-MM-DDThh:mm:ss
-    time_t rawtime;
+    auto rawtime = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
-    struct tm* timeinfo;
+    tm timeinfo{};
-
+#ifdef _WIN32
-    time(&rawtime);
+    (void)localtime_s(&timeinfo, &rawtime);
-    timeinfo = localtime(&rawtime);
+#else
+    (void)localtime_r(&rawtime, &timeinfo);
+#endif
     int base = 10;
     QChar zeroPad('0');
     return QString("%1-%2-%3T%4:%5:%6")
-        .arg(timeinfo->tm_year + 1900, 4)
+        .arg(timeinfo.tm_year + 1900, 4)
-        .arg(timeinfo->tm_mon + 1, 2, base, zeroPad)
+        .arg(timeinfo.tm_mon + 1, 2, base, zeroPad)
-        .arg(timeinfo->tm_mday, 2, base, zeroPad)
+        .arg(timeinfo.tm_mday, 2, base, zeroPad)
-        .arg(timeinfo->tm_hour, 2, base, zeroPad)
+        .arg(timeinfo.tm_hour, 2, base, zeroPad)
-        .arg(timeinfo->tm_min, 2, base, zeroPad)
+        .arg(timeinfo.tm_min, 2, base, zeroPad)
-        .arg(timeinfo->tm_sec, 2, base, zeroPad);
+        .arg(timeinfo.tm_sec, 2, base, zeroPad);
 }

components/debug/debugging.cpp

@@ -99,7 +99,13 @@ namespace Debug
                 prefix[0] = '[';
                 const auto now = std::chrono::system_clock::now();
                 const auto time = std::chrono::system_clock::to_time_t(now);
-                prefixSize = std::strftime(prefix + 1, sizeof(prefix) - 1, "%T", std::localtime(&time)) + 1;
+                tm time_info{};
+#ifdef _WIN32
+                (void)localtime_s(&time_info, &time);
+#else
+                (void)localtime_r(&time, &time_info);
+#endif
+                prefixSize = std::strftime(prefix + 1, sizeof(prefix) - 1, "%T", &time_info) + 1;
                 char levelLetter = " EWIVD*"[int(level)];
                 const auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(now.time_since_epoch()).count();
                 prefixSize += snprintf(prefix + prefixSize, sizeof(prefix) - prefixSize, ".%03u %c] ",

components/misc/timeconvert.hpp

@@ -2,17 +2,39 @@
 #define OPENMW_COMPONENTS_MISC_TIMECONVERT_H
 
 #include <chrono>
-#include <ctime>
 
 namespace Misc
 {
     template <typename TP>
-    inline std::time_t to_time_t(TP tp)
+    inline std::time_t toTimeT(TP tp)
     {
         using namespace std::chrono;
         auto sctp = time_point_cast<system_clock::duration>(tp - TP::clock::now() + system_clock::now());
         return system_clock::to_time_t(sctp);
     }
+
+    inline std::string timeTToString(const std::time_t tp, const char* fmt)
+    {
+        tm time_info{};
+#ifdef _WIN32
+        (void)localtime_s(&time_info, &tp);
+#else
+        (void)localtime_r(&tp, &time_info);
+#endif
+        std::stringstream out;
+        out << std::put_time(&time_info, fmt);
+        return out.str();
+    }
+
+    inline std::string fileTimeToString(const std::filesystem::file_time_type& tp, const char* fmt)
+    {
+        return timeTToString(toTimeT(tp), fmt);
+    }
+
+    inline std::string timeToString(const std::chrono::system_clock::time_point& tp, const char* fmt)
+    {
+        return timeTToString(std::chrono::system_clock::to_time_t(tp), fmt);
+    }
 } // namespace Misc
 
 #endif