From a0a8b02e26697f932f8d2285b8166aa3fc632414 Mon Sep 17 00:00:00 2001
From: Stephan Sundermann <stephansundermann@gmail.com>
Date: Sat, 30 Sep 2023 02:18:20 +0200
Subject: [PATCH] [PosixTimezone] Refactor timezone reading

---
 xbmc/platform/posix/PosixTimezone.cpp | 90 +++++++++++++++------------
 xbmc/platform/posix/PosixTimezone.h   | 14 +++--
 2 files changed, 58 insertions(+), 46 deletions(-)

diff --git a/xbmc/platform/posix/PosixTimezone.cpp b/xbmc/platform/posix/PosixTimezone.cpp
index 1a1f7d59fbd5f..56297bb54b7ca 100644
--- a/xbmc/platform/posix/PosixTimezone.cpp
+++ b/xbmc/platform/posix/PosixTimezone.cpp
@@ -6,21 +6,24 @@
  *  See LICENSES/README.md for more information.
  */
 
-#include <time.h>
-#include "PlatformDefs.h"
 #include "PosixTimezone.h"
-#include "utils/SystemInfo.h"
 
 #include "ServiceBroker.h"
-#include "utils/StringUtils.h"
 #include "XBDateTime.h"
-#include "settings/lib/Setting.h"
-#include "settings/lib/SettingDefinitions.h"
 #include "settings/Settings.h"
 #include "settings/SettingsComponent.h"
-#include <stdlib.h>
+#include "settings/lib/Setting.h"
+#include "settings/lib/SettingDefinitions.h"
+#include "utils/StringUtils.h"
+#include "utils/SystemInfo.h"
 
 #include <algorithm>
+#include <cstdlib>
+#include <ctime>
+#include <filesystem>
+#include <fstream>
+
+#include "PlatformDefs.h"
 
 CPosixTimezone::CPosixTimezone()
 {
@@ -195,44 +198,51 @@ void CPosixTimezone::SetTimezone(const std::string& timezoneName)
 
 std::string CPosixTimezone::GetOSConfiguredTimezone()
 {
-   char timezoneName[255];
+  std::string timezoneName;
 
-   // try Slackware approach first
-   ssize_t rlrc = readlink("/etc/localtime-copied-from"
-                           , timezoneName, sizeof(timezoneName)-1);
+  // try Slackware approach first
+  timezoneName = ReadFromLocaltime("/etc/localtime-copied-from");
 
-   // RHEL and maybe other distros make /etc/localtime a symlink
-   if (rlrc == -1)
-     rlrc = readlink("/etc/localtime", timezoneName, sizeof(timezoneName)-1);
+  // RHEL and maybe other distros make /etc/localtime a symlink
+  if (timezoneName.empty())
+    timezoneName = ReadFromLocaltime("/etc/localtime");
 
-   if (rlrc != -1)
-   {
-     timezoneName[rlrc] = '\0';
-
-     char* p = strrchr(timezoneName,'/');
-     if (p)
-     { // we want the previous '/'
-       char* q = p;
-       *q = 0;
-       p = strrchr(timezoneName,'/');
-       *q = '/';
-       if (p)
-         p++;
-     }
-     return p;
-   }
+  // now try Debian approach
+  if (timezoneName.empty())
+    timezoneName = ReadFromTimezone("/etc/timezone");
 
-   // now try Debian approach
-   timezoneName[0] = 0;
-   FILE* fp = fopen("/etc/timezone", "r");
-   if (fp)
-   {
-      if (fgets(timezoneName, sizeof(timezoneName), fp))
-        timezoneName[strlen(timezoneName)-1] = '\0';
-      fclose(fp);
-   }
+  return timezoneName;
+}
+
+std::string CPosixTimezone::ReadFromLocaltime(const std::string_view filename)
+{
+  std::error_code e;
+  std::string path = std::filesystem::read_symlink(filename, e);
+
+  // Read the timezone starting from the second last occurrence of /
+  size_t pos = path.rfind('/');
+  if (pos == std::string::npos)
+    return "";
+
+  pos = path.rfind('/', pos - 1);
+  if (pos == std::string::npos)
+    return "";
+
+  return path.substr(pos + 1);
+}
+
+std::string CPosixTimezone::ReadFromTimezone(const std::string_view filename)
+{
+  std::string timezoneName;
+  std::ifstream file(filename.data());
+
+  if (file.is_open())
+  {
+    std::getline(file, timezoneName);
+    file.close();
+  }
 
-   return timezoneName;
+  return timezoneName;
 }
 
 void CPosixTimezone::SettingOptionsTimezoneCountriesFiller(
diff --git a/xbmc/platform/posix/PosixTimezone.h b/xbmc/platform/posix/PosixTimezone.h
index 076e87fa51e98..26a7f0934079c 100644
--- a/xbmc/platform/posix/PosixTimezone.h
+++ b/xbmc/platform/posix/PosixTimezone.h
@@ -46,12 +46,14 @@ class CPosixTimezone : public ISettingCallback, public ISettingsHandler
                                             void* data);
 
 private:
-   std::vector<std::string> m_counties;
-   std::map<std::string, std::string> m_countryByCode;
-   std::map<std::string, std::string> m_countryByName;
-
-   std::map<std::string, std::vector<std::string> > m_timezonesByCountryCode;
-   std::map<std::string, std::string> m_countriesByTimezoneName;
+  std::string ReadFromLocaltime(std::string_view filename);
+  std::string ReadFromTimezone(std::string_view filename);
+  std::vector<std::string> m_counties;
+  std::map<std::string, std::string> m_countryByCode;
+  std::map<std::string, std::string> m_countryByName;
+
+  std::map<std::string, std::vector<std::string>> m_timezonesByCountryCode;
+  std::map<std::string, std::string> m_countriesByTimezoneName;
 };
 
 extern CPosixTimezone g_timezone;