Improve container ID extraction logic for complex Docker service format

ProcessInfo.cpp

@@ -413,10 +413,21 @@ int ProcessInfo::ExtractCGroupContainerId(const std::string& content) {
         // Check for complex docker format
         const char *complex_format_pos = strstr(ptr, complex_docker_service_prefix);
         if (complex_format_pos != nullptr && complex_format_pos < line_end) {
-            const char *id_start = strrchr(ptr, '/') + 1;
-            if (id_start != nullptr) {
-                _container_id = std::string(id_start, 12); // Extract the container ID from the end of the line
-                return 0;
+             // Search for '/' before line_end
+            const char *id_start = nullptr;
+            for (const char *p = line_end; p >= complex_format_pos; --p) {
+                if (*p == '/') {
+                    id_start = p + 1;
+                    break;
+                }
+            }
+
+            if (id_start != nullptr) {                            
+                // make sure we have 12 characters left in the line before i read them
+                if (line_end > id_start && id_start + 12 <= line_end) { 
+                    _container_id = std::string(id_start, 12); // Extract the container ID from the end of the line                      
+                    return 0;
+                }
             }
         }