From 33c17908501d5b1d528432b6f06954dc5002a41b Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Fri, 12 Apr 2024 08:10:03 -0400
Subject: [PATCH] Add a os_utils helper for locatime->put_time

---
 src/cli/tls_http_server.cpp            | 14 +-------------
 src/lib/utils/os_utils.cpp             | 22 ++++++++++++++++++++++
 src/lib/utils/os_utils.h               |  8 ++++++++
 src/tests/runner/test_xml_reporter.cpp | 18 ++----------------
 4 files changed, 33 insertions(+), 29 deletions(-)

diff --git a/src/cli/tls_http_server.cpp b/src/cli/tls_http_server.cpp
index e5c57f22deb..cfbc17111e6 100644
--- a/src/cli/tls_http_server.cpp
+++ b/src/cli/tls_http_server.cpp
@@ -63,19 +63,7 @@ using tcp_stream = typename beast::tcp_stream::rebind_executor<
 
 class Logger final {
    private:
-      auto timestamp() const {
-         const auto t = std::time(nullptr);
-         struct tm tm;
-
-   #if defined(BOTAN_BUILD_COMPILER_IS_MSVC) || defined(BOTAN_TARGET_OS_IS_MINGW) || \
-      defined(BOTAN_TARGET_OS_IS_CYGWIN) || defined(BOTAN_TARGET_OS_IS_WINDOWS)
-         localtime_s(&tm, &t);
-   #else
-         localtime_r(&t, &tm);
-   #endif
-
-         return std::put_time(&tm, "%c");
-      }
+      std::string timestamp() const { return Botan::OS::format_time(std::time(nullptr), "%c"); }
 
    public:
       Logger(std::ostream& out, std::ostream& err) : m_out(out), m_err(err) {}
diff --git a/src/lib/utils/os_utils.cpp b/src/lib/utils/os_utils.cpp
index 6b37e32f1fb..45bea5daa16 100644
--- a/src/lib/utils/os_utils.cpp
+++ b/src/lib/utils/os_utils.cpp
@@ -15,6 +15,8 @@
 #include <algorithm>
 #include <chrono>
 #include <cstdlib>
+#include <iomanip>
+#include <sstream>
 
 #if defined(BOTAN_TARGET_OS_HAS_EXPLICIT_BZERO)
    #include <string.h>
@@ -325,6 +327,26 @@ uint64_t OS::get_system_timestamp_ns() {
    return std::chrono::duration_cast<std::chrono::nanoseconds>(now).count();
 }
 
+std::string OS::format_time(time_t time, const std::string& format) {
+   std::tm tm;
+
+#if defined(BOTAN_TARGET_OS_HAS_WIN32)
+   localtime_s(&tm, &time);
+#elif defined(BOTAN_TARGET_OS_HAS_POSIX1)
+   localtime_r(&time, &tm);
+#else
+   if(auto tmp = std::localtime(&time)) {
+      tm = *tmp;
+   } else {
+      throw Encoding_Error("Could not convert time_t to localtime");
+   }
+#endif
+
+   std::ostringstream oss;
+   oss << std::put_time(&tm, format.c_str());
+   return oss.str();
+}
+
 size_t OS::system_page_size() {
    const size_t default_page_size = 4096;
 
diff --git a/src/lib/utils/os_utils.h b/src/lib/utils/os_utils.h
index cda39f10a06..465e7974fee 100644
--- a/src/lib/utils/os_utils.h
+++ b/src/lib/utils/os_utils.h
@@ -84,6 +84,14 @@ uint64_t BOTAN_TEST_API get_high_resolution_clock();
 */
 uint64_t BOTAN_TEST_API get_system_timestamp_ns();
 
+/**
+* Format a time
+*
+* Converts the time_t to a local time representation,
+* then invokes std::put_time with the specified format.
+*/
+std::string BOTAN_TEST_API format_time(time_t time, const std::string& format);
+
 /**
 * @return maximum amount of memory (in bytes) Botan could/should
 * hyptothetically allocate for the memory poool. Reads environment
diff --git a/src/tests/runner/test_xml_reporter.cpp b/src/tests/runner/test_xml_reporter.cpp
index 9810b40e767..8a69e4b579f 100644
--- a/src/tests/runner/test_xml_reporter.cpp
+++ b/src/tests/runner/test_xml_reporter.cpp
@@ -12,11 +12,11 @@
    #include <botan/build.h>
    #include <botan/version.h>
    #include <botan/internal/loadstor.h>
+   #include <botan/internal/os_utils.h>
 
    #include <iomanip>
    #include <numeric>
    #include <sstream>
-   #include <time.h>
 
 namespace Botan_Tests {
 
@@ -60,24 +60,10 @@ std::string full_compiler_name_string() {
    #endif
 }
 
-std::tm* localtime(const time_t* timer, std::tm* buffer) {
-   #if defined(BOTAN_BUILD_COMPILER_IS_MSVC) || defined(BOTAN_TARGET_OS_IS_MINGW) || \
-      defined(BOTAN_TARGET_OS_IS_CYGWIN) || defined(BOTAN_TARGET_OS_IS_WINDOWS)
-   localtime_s(buffer, timer);
-   #else
-   localtime_r(timer, buffer);
-   #endif
-   return buffer;
-}
-
 /// formats a given time point in ISO 8601 format (with time zone)
 std::string format(const std::chrono::system_clock::time_point& tp) {
    auto seconds_since_epoch = std::chrono::system_clock::to_time_t(tp);
-
-   std::ostringstream out;
-   std::tm buffer{};
-   out << std::put_time(localtime(&seconds_since_epoch, &buffer), "%FT%T%z");
-   return out.str();
+   return Botan::OS::format_time(seconds_since_epoch, "%FT%T%z");
 }
 
 std::string format(const std::chrono::nanoseconds& dur) {