libsysprof-profile: add scaffolding for controlfd source

This is internal to the profile and will always be active when running
subprocesses with Sysprof.

src/libsysprof-profile/meson.build

@@ -5,6 +5,7 @@ libsysprof_profile_public_sources = [
 ]
 
 libsysprof_profile_private_sources = [
+  'sysprof-controlfd-instrument.c',
 ]
 
 libsysprof_profile_public_headers = [

src/libsysprof-profile/sysprof-controlfd-instrument-private.h

@@ -0,0 +1,33 @@
+/* sysprof-controlfd-instrument-private.h
+ *
+ * Copyright 2023 Christian Hergert <chergert@redhat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include "sysprof-instrument-private.h"
+
+G_BEGIN_DECLS
+
+#define SYSPROF_TYPE_CONTROLFD_INSTRUMENT (sysprof_controlfd_instrument_get_type())
+
+G_DECLARE_FINAL_TYPE (SysprofControlfdInstrument, sysprof_controlfd_instrument, SYSPROF, CONTROLFD_INSTRUMENT, SysprofInstrument)
+
+SysprofInstrument *_sysprof_controlfd_instrument_new (void);
+
+G_END_DECLS

src/libsysprof-profile/sysprof-controlfd-instrument.c

@@ -0,0 +1,57 @@
+/* sysprof-controlfd-instrument.c
+ *
+ * Copyright 2023 Christian Hergert <chergert@redhat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "config.h"
+
+#include "sysprof-controlfd-instrument-private.h"
+
+struct _SysprofControlfdInstrument
+{
+  SysprofInstrument parent_instance;
+};
+
+G_DEFINE_FINAL_TYPE (SysprofControlfdInstrument, sysprof_controlfd_instrument, SYSPROF_TYPE_INSTRUMENT)
+
+static void
+sysprof_controlfd_instrument_finalize (GObject *object)
+{
+  SysprofControlfdInstrument *self = (SysprofControlfdInstrument *)object;
+
+  G_OBJECT_CLASS (sysprof_controlfd_instrument_parent_class)->finalize (object);
+}
+
+static void
+sysprof_controlfd_instrument_class_init (SysprofControlfdInstrumentClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = sysprof_controlfd_instrument_finalize;
+}
+
+static void
+sysprof_controlfd_instrument_init (SysprofControlfdInstrument *self)
+{
+}
+
+SysprofInstrument *
+_sysprof_controlfd_instrument_new (void)
+{
+  return g_object_new (SYSPROF_TYPE_CONTROLFD_INSTRUMENT, NULL);
+}

src/libsysprof-profile/sysprof-profiler.c

@@ -20,6 +20,7 @@
 
 #include "config.h"
 
+#include "sysprof-controlfd-instrument-private.h"
 #include "sysprof-profiler.h"
 #include "sysprof-recording-private.h"
 
@@ -82,6 +83,8 @@ static void
 sysprof_profiler_init (SysprofProfiler *self)
 {
   self->instruments = g_ptr_array_new_with_free_func (g_object_unref);
+
+  sysprof_profiler_add_instrument (self, _sysprof_controlfd_instrument_new ());
 }
 
 SysprofProfiler *