libsysprof-profile: start on linux host info instrument

This instrument is meant to gather information about the host that we will
need as part of the capture to decode things properly.

src/libsysprof-profile/meson.build

@@ -20,6 +20,12 @@ libsysprof_profile_public_headers = [
   'sysprof-spawnable.h',
 ]
 
+if host_machine.system() == 'linux'
+  libsysprof_profile_private_sources += [
+    'sysprof-linux-instrument.c',
+  ]
+endif
+
 libsysprof_profile_deps = [
   dependency('gio-2.0', version: glib_req_version),
   dependency('gio-unix-2.0',

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

@@ -0,0 +1,33 @@
+/* sysprof-linux-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_LINUX_INSTRUMENT (sysprof_linux_instrument_get_type())
+
+G_DECLARE_FINAL_TYPE (SysprofLinuxInstrument, sysprof_linux_instrument, SYSPROF, LINUX_INSTRUMENT, SysprofInstrument)
+
+SysprofInstrument *_sysprof_linux_instrument_new (void);
+
+G_END_DECLS

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

@@ -0,0 +1,145 @@
+/* sysprof-linux-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-linux-instrument-private.h"
+#include "sysprof-recording-private.h"
+
+struct _SysprofLinuxInstrument
+{
+  SysprofInstrument parent_instance;
+};
+
+enum {
+  PROP_0,
+  N_PROPS
+};
+
+G_DEFINE_FINAL_TYPE (SysprofLinuxInstrument, sysprof_linux_instrument, SYSPROF_TYPE_INSTRUMENT)
+
+static gboolean
+sysprof_linux_instrument_capture_file (SysprofCaptureWriter  *writer,
+                                       const char            *path,
+                                       gboolean               compress,
+                                       GError               **error)
+{
+  g_autoptr(GBytes) bytes = NULL;
+  g_autoptr(GFile) file = NULL;
+  const guint8 *data;
+  gsize len;
+
+  g_assert (writer != NULL);
+  g_assert (path != NULL);
+
+  file = g_file_new_for_path (path);
+
+  /* TODO: This needs to go through sysprofd instead */
+
+  if (!(bytes = dex_await_boxed (dex_file_load_contents_bytes (file), error)))
+    return FALSE;
+
+  /* TODO: Handle compression of files */
+
+  data = g_bytes_get_data (bytes, &len);
+
+  while (len > 0)
+    {
+      gsize to_write = MIN (len, 4096*8);
+
+      if (!sysprof_capture_writer_add_file (writer,
+                                            SYSPROF_CAPTURE_CURRENT_TIME,
+                                            -1,
+                                            -1,
+                                            path,
+                                            to_write == len,
+                                            data,
+                                            to_write))
+        break;
+
+      len -= to_write;
+      data += to_write;
+    }
+
+  return TRUE;
+}
+
+static DexFuture *
+sysprof_linux_instrument_prepare_fiber (gpointer user_data)
+{
+  SysprofRecording *recording = user_data;
+  SysprofCaptureWriter *writer;
+
+  g_assert (SYSPROF_IS_RECORDING (recording));
+
+  writer = _sysprof_recording_writer (recording);
+
+  /* Capture information about the system as we see it from the host system.
+   * We must query this via sysprofd so that our current process (which may
+   * have a different mount namespace) does not fall into the capture file.
+   */
+
+  sysprof_linux_instrument_capture_file (writer, "/proc/cpuinfo", FALSE, NULL);
+  sysprof_linux_instrument_capture_file (writer, "/proc/mounts", FALSE, NULL);
+  sysprof_linux_instrument_capture_file (writer, "/proc/kallsyms", TRUE, NULL);
+
+  return dex_future_new_for_boolean (TRUE);
+}
+
+static DexFuture *
+sysprof_linux_instrument_prepare (SysprofInstrument *instrument,
+                                  SysprofRecording  *recording)
+{
+  g_assert (SYSPROF_IS_INSTRUMENT (instrument));
+  g_assert (SYSPROF_IS_RECORDING (recording));
+
+  return dex_scheduler_spawn (NULL, 0,
+                              sysprof_linux_instrument_prepare_fiber,
+                              g_object_ref (recording),
+                              g_object_unref);
+}
+
+static void
+sysprof_linux_instrument_finalize (GObject *object)
+{
+  G_OBJECT_CLASS (sysprof_linux_instrument_parent_class)->finalize (object);
+}
+
+static void
+sysprof_linux_instrument_class_init (SysprofLinuxInstrumentClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+  SysprofInstrumentClass *instrument_class = SYSPROF_INSTRUMENT_CLASS (klass);
+
+  object_class->finalize = sysprof_linux_instrument_finalize;
+
+  instrument_class->prepare = sysprof_linux_instrument_prepare;
+}
+
+static void
+sysprof_linux_instrument_init (SysprofLinuxInstrument *self)
+{
+}
+
+SysprofInstrument *
+_sysprof_linux_instrument_new (void)
+{
+  return g_object_new (SYSPROF_TYPE_LINUX_INSTRUMENT, NULL);
+}