fix(libsinsp): expose main thread fd table

Signed-off-by: Gianmatteo Palmieri <[email protected]>

userspace/libsinsp/threadinfo.cpp

@@ -50,6 +50,7 @@ sinsp_threadinfo::sinsp_threadinfo(
         m_cgroups(new cgroups_t),
         m_inspector(inspector),
         m_fdtable(inspector),
+        m_main_fdtable(m_fdtable.table_ptr()),
         m_args_table_adapter("args", m_args),
         m_env_table_adapter("env", m_env) {
 	init();
@@ -105,7 +106,7 @@ libsinsp::state::static_struct::field_infos sinsp_threadinfo::static_fields() co
 	// m_clone_ts
 	// m_lastexec_ts
 	// m_latency
-	define_static_field(ret, this, m_fdtable.table_ptr(), "file_descriptors", true);
+	define_static_field(ret, this, m_main_fdtable, "file_descriptors", true);
 	define_static_field(ret, this, m_cwd, "cwd", true);
 	// m_parent_loop_detected
 	return ret;
@@ -1231,6 +1232,13 @@ void sinsp_threadinfo::strvec_to_iovec(const std::vector<std::string>& strs,
 	}
 }
 
+void sinsp_threadinfo::update_main_fdtable() {
+	auto fdtable = get_fd_table();
+	if(fdtable) {
+		m_main_fdtable = static_cast<const libsinsp::state::base_table*>(fdtable->table_ptr());
+	}
+}
+
 static void fd_to_scap(scap_fdinfo* dst, sinsp_fdinfo* src) {
 	dst->type = src->m_type;
 	dst->ino = src->m_ino;
@@ -1385,6 +1393,8 @@ void sinsp_thread_manager::create_thread_dependencies(
 		return;
 	}
 	parent_thread->add_child(tinfo);
+
+	tinfo->update_main_fdtable();
 }
 
 std::unique_ptr<sinsp_threadinfo> sinsp_thread_manager::new_threadinfo() const {

userspace/libsinsp/threadinfo.h

@@ -630,6 +630,8 @@ class SINSP_PUBLIC sinsp_threadinfo : public libsinsp::state::table_entry {
 	        const std::function<std::string(sinsp_threadinfo*)>& get_field_str,
 	        bool is_virtual_id = false);
 
+	void update_main_fdtable();
+
 private:
 	sinsp_threadinfo* get_cwd_root();
 	bool set_env_from_proc();
@@ -649,7 +651,9 @@ class SINSP_PUBLIC sinsp_threadinfo : public libsinsp::state::table_entry {
 	// Parameters that can't be accessed directly because they could be in the
 	// parent thread info
 	//
-	sinsp_fdtable m_fdtable;    // The fd table of this thread
+	sinsp_fdtable m_fdtable;  // The fd table of this thread
+	const libsinsp::state::base_table*
+	        m_main_fdtable;     // Points to the base fd table of the current main thread
 	std::string m_cwd;          // current working directory
 	uint8_t* m_lastevent_data;  // Used by some event parsers to store the last enter event