Fix C API time signature access

Author: liturner

README.md

@@ -108,6 +108,27 @@ lintian --info --pedantic --display-info ../nmbs_*_amd64.changes
 sudo apt install ./nmbs_*_amd64.deb ./libnmbs1_*_amd64.deb
 nautilus -q
 
+# Check d/watch is working
+uscan -v --no-download
+
+```
+
+## Nautilus Development
+
+It is quite easy to develop for Nautilus. Quite simply, symlink the debug .so to the nautilus extensions folder.
+Important to know is that Nautilus runs with a daemon in the background. You must sometimes kill this or the module
+will not reload.
+
+Check the run configurations of NMBS-Nautilus to see how to Debug. In CLion this is stored in git, so just debug
+the target to start Nautilus with gdb.
+```shell
+nautilus -q
+```
+```shell
+sudo ln -s $PWD/build/debug/targets/NMBS-Nautilus/libnmbs-nautilusd.so /usr/lib/x86_64-linux-gnu/nautilus/extensions-4/libnmbs-nautilus.so 
+```
+```shell
+sudo rm /usr/lib/x86_64-linux-gnu/nautilus/extensions-4/libnmbs-nautilus.so
 ```
 
 # Runtime Environment Variables

targets/NMBS-Library/include/public/nmbs/nmbs_c.h

@@ -187,11 +187,13 @@ void nmbs_confidentiality_labels_read_labels_with_known_binding(nmbs_confidentia
 /// @return Pointer to the underlying data. Do not free or delete this!
 [[nodiscard]] const char* nmbs_confidentiality_label_get_classification(nmbs_confidentiality_label_ptr label) NMBS_NOEXCEPT;
 
-/// @brief Opaque Accessor
+/// @brief Opaque Generator
 /// @ingroup c_confidentiality_labels
 /// @param label
-/// @return
-[[nodiscard]] const char* nmbs_confidentiality_label_get_creation_date_time(nmbs_confidentiality_label_ptr label) NMBS_NOEXCEPT;
+/// @param out_buffer
+/// @param out_buffer_size
+unsigned int nmbs_confidentiality_label_get_creation_date_time(nmbs_confidentiality_label_ptr label, char* out_buffer,
+                                                               unsigned int out_buffer_size) NMBS_NOEXCEPT;
 
 /// @brief Opaque Accessor
 /// @ingroup c_confidentiality_labels

targets/NMBS-Library/src/nmbs_c.cpp

@@ -29,6 +29,7 @@
 
 #include <iostream>
 #include <sstream>
+#include <string.h>
 #include <string>
 
 #include "nmbs/exit_code.h"
@@ -258,25 +259,29 @@ const char* nmbs_confidentiality_label_get_classification(nmbs_confidentiality_l
     }
 }
 
-const char* nmbs_confidentiality_label_get_creation_date_time(nmbs_confidentiality_label_ptr label) noexcept
+unsigned int nmbs_confidentiality_label_get_creation_date_time(nmbs_confidentiality_label_ptr label, char* out_buffer,
+                                                               const unsigned int out_buffer_size) noexcept
 {
     try
     {
-        auto cpp_label = to_cpp_label(label);
+        auto const cpp_label = to_cpp_label(label);
         if (cpp_label == nullptr)
         {
-            return nullptr;
+            return 0;
+        }
+        auto const timepoint = cpp_label->creation_date_time;auto timepoint_string = std::format(std::locale(""), "{:L%c}", timepoint);
+
+        if (out_buffer_size > timepoint_string.size())
+        {
+            strcpy(out_buffer, timepoint_string.c_str());
+            return timepoint_string.size();
         }
-        auto timepoint = cpp_label->creation_date_time;
-        // TODO: This is slightly dangerous. I think in reality it is fine for this use case, but academically
-        // speaking its possible to get failures caused here.
-        thread_local auto timepoint_string = std::format(std::locale(""), "{:L%c}", timepoint);
-        return  timepoint_string.c_str();
+        return 0;
     }
     catch (...)
     {
         std::cerr << "C++ Exception caught in nmbs_confidentiality_label_get_creation_date_time" << std::endl;
-        return nullptr;
+        return 0;
     }
 }
 

targets/NMBS-Nautilus/src/nmbs-nautilus.c

@@ -120,10 +120,11 @@ static NautilusOperationResult nmbs_properties_update_file_info(
             auto const label_policy = nmbs_confidentiality_label_get_policy(label);
             auto const label_classification = nmbs_confidentiality_label_get_classification(label);
             auto const label_originator = nmbs_confidentiality_label_get_originator_id(label);
-            auto const label_time = nmbs_confidentiality_label_get_creation_date_time(label);
+            char label_time[100];
+            auto const label_time_size = nmbs_confidentiality_label_get_creation_date_time(label, label_time, sizeof(label_time));
 
             // These are mandatory fields for a label.
-            if (!label || !label_policy || !label_classification || !label_time)
+            if (!label || !label_policy || !label_classification || label_time_size == 0)
             {
                 continue;
             }