[sysprof] libsysprof: move tracefd to separate source

[Christian Hergert <chergert src gnome org>]

commit 552ccb4f6086eeb86fe3d317105d7493439aef28
Author: Christian Hergert <chergert redhat com>
Date:   Fri May 24 16:01:32 2019 -0700

    libsysprof: move tracefd to separate source

 src/libsysprof/meson.build              |   2 +
 src/libsysprof/sysprof-proxy-source.c   |  40 -----
 src/libsysprof/sysprof-tracefd-source.c | 290 ++++++++++++++++++++++++++++++++
 src/libsysprof/sysprof-tracefd-source.h |  49 ++++++
 src/libsysprof/sysprof.h                |   1 +
 5 files changed, 342 insertions(+), 40 deletions(-)
---
diff --git a/src/libsysprof/meson.build b/src/libsysprof/meson.build
index 6d47e15..2a7d40f 100644
--- a/src/libsysprof/meson.build
+++ b/src/libsysprof/meson.build
@@ -20,6 +20,7 @@ libsysprof_public_sources = [
   'sysprof-source.c',
   'sysprof-symbol-dirs.c',
   'sysprof-symbol-resolver.c',
+  'sysprof-tracefd-source.c',
 ]
 
 libsysprof_public_headers = [
@@ -42,6 +43,7 @@ libsysprof_public_headers = [
   'sysprof-source.h',
   'sysprof-symbol-dirs.h',
   'sysprof-symbol-resolver.h',
+  'sysprof-tracefd-source.h',
   'sysprof.h',
 ]
 
diff --git a/src/libsysprof/sysprof-proxy-source.c b/src/libsysprof/sysprof-proxy-source.c
index d38716b..536c51e 100644
--- a/src/libsysprof/sysprof-proxy-source.c
+++ b/src/libsysprof/sysprof-proxy-source.c
@@ -375,12 +375,6 @@ sysprof_proxy_source_start (SysprofSource *source)
 
   self->has_started = TRUE;
 
-  /* If we're doing subprocess monitoring, we don't need to do
-   * anything special here to connect to a bus.
-   */
-  if (self->monitors->len > 0)
-    return;
-
   g_bus_get (self->bus_type,
              self->cancellable,
              sysprof_proxy_source_get_bus_cb,
@@ -504,39 +498,6 @@ sysprof_proxy_source_add_pid (SysprofSource *source,
   g_array_append_val (self->pids, pid);
 }
 
-static void
-sysprof_proxy_source_modify_spawn (SysprofSource       *source,
-                                   GSubprocessLauncher *launcher,
-                                   GPtrArray           *argv)
-{
-  SysprofProxySource *self = (SysprofProxySource *)source;
-  gchar fdstr[12];
-  Monitor *monitor;
-  gint fd;
-
-  g_assert (SYSPROF_IS_PROXY_SOURCE (self));
-  g_assert (G_IS_SUBPROCESS_LAUNCHER (launcher));
-  g_assert (argv != NULL);
-
-  /* We need to create a new FD for the peer process to write
-   * to and notify it via SYSPROF_TRACE_FD. We will largely
-   * ignore things until the capture has finished.
-   */
-
-  if (-1 == (fd = sysprof_memfd_create ("[sysprof-proxy-capture]")))
-    return;
-
-  monitor = g_slice_new0 (Monitor);
-  monitor->self = g_object_ref (self);
-  monitor->fd = dup (fd);
-
-  g_snprintf (fdstr, sizeof fdstr, "%d", fd);
-  g_subprocess_launcher_setenv (launcher, "SYSPROF_TRACE_FD", fdstr, TRUE);
-  g_subprocess_launcher_take_fd (launcher, fd, fd);
-
-  sysprof_proxy_source_take_monitor (self, g_steal_pointer (&monitor));
-}
-
 static void
 sysprof_proxy_source_serialize (SysprofSource *source,
                                 GKeyFile      *keyfile,
@@ -585,7 +546,6 @@ source_iface_init (SysprofSourceInterface *iface)
   iface->get_is_ready = sysprof_proxy_source_get_is_ready;
   iface->stop = sysprof_proxy_source_stop;
   iface->start = sysprof_proxy_source_start;
-  iface->modify_spawn = sysprof_proxy_source_modify_spawn;
   iface->serialize = sysprof_proxy_source_serialize;
   iface->deserialize = sysprof_proxy_source_deserialize;
 }
diff --git a/src/libsysprof/sysprof-tracefd-source.c b/src/libsysprof/sysprof-tracefd-source.c
new file mode 100644
index 0000000..5a57c55
--- /dev/null
+++ b/src/libsysprof/sysprof-tracefd-source.c
@@ -0,0 +1,290 @@
+/* sysprof-tracefd-source.c
+ *
+ * Copyright 2019 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
+ */
+
+#define G_LOG_DOMAIN "sysprof-tracefd-source"
+
+#include "config.h"
+
+#include <errno.h>
+#include <sysprof-capture.h>
+
+#include "sysprof-platform.h"
+#include "sysprof-tracefd-source.h"
+
+typedef struct
+{
+  SysprofCaptureWriter *writer;
+  gchar                *envvar;
+  gint                  tracefd;
+} SysprofTracefdSourcePrivate;
+
+enum {
+  PROP_0,
+  PROP_ENVVAR,
+  N_PROPS
+};
+
+static void source_iface_init (SysprofSourceInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (SysprofTracefdSource, sysprof_tracefd_source, G_TYPE_OBJECT,
+                         G_ADD_PRIVATE (SysprofTracefdSource)
+                         G_IMPLEMENT_INTERFACE (SYSPROF_TYPE_SOURCE, source_iface_init))
+
+static GParamSpec *properties [N_PROPS];
+
+static void
+sysprof_tracefd_source_finalize (GObject *object)
+{
+  SysprofTracefdSource *self = (SysprofTracefdSource *)object;
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  g_clear_pointer (&priv->writer, sysprof_capture_writer_unref);
+  g_clear_pointer (&priv->envvar, g_free);
+
+  if (priv->tracefd != -1)
+    {
+      close (priv->tracefd);
+      priv->tracefd = -1;
+    }
+
+  G_OBJECT_CLASS (sysprof_tracefd_source_parent_class)->finalize (object);
+}
+
+static void
+sysprof_tracefd_source_get_property (GObject    *object,
+                                     guint       prop_id,
+                                     GValue     *value,
+                                     GParamSpec *pspec)
+{
+  SysprofTracefdSource *self = SYSPROF_TRACEFD_SOURCE (object);
+
+  switch (prop_id)
+    {
+    case PROP_ENVVAR:
+      g_value_set_string (value, sysprof_tracefd_source_get_envvar (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+sysprof_tracefd_source_set_property (GObject      *object,
+                                     guint         prop_id,
+                                     const GValue *value,
+                                     GParamSpec   *pspec)
+{
+  SysprofTracefdSource *self = SYSPROF_TRACEFD_SOURCE (object);
+
+  switch (prop_id)
+    {
+    case PROP_ENVVAR:
+      sysprof_tracefd_source_set_envvar (self, g_value_get_string (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+sysprof_tracefd_source_class_init (SysprofTracefdSourceClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = sysprof_tracefd_source_finalize;
+  object_class->get_property = sysprof_tracefd_source_get_property;
+  object_class->set_property = sysprof_tracefd_source_set_property;
+
+  properties [PROP_ENVVAR] =
+    g_param_spec_string ("envvar",
+                         "Environment Variable",
+                         "The environment variable to set",
+                         "SYSPROF_TRACE_FD",
+                         (G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+  
+  g_object_class_install_properties (object_class, N_PROPS, properties);
+}
+
+static void
+sysprof_tracefd_source_init (SysprofTracefdSource *self)
+{
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  priv->tracefd = -1;
+  priv->envvar = g_strdup ("SYSPROF_TRACE_FD");
+}
+
+const gchar *
+sysprof_tracefd_source_get_envvar (SysprofTracefdSource *self)
+{
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  g_return_val_if_fail (SYSPROF_IS_TRACEFD_SOURCE (self), NULL);
+
+  return priv->envvar;
+}
+
+void
+sysprof_tracefd_source_set_envvar (SysprofTracefdSource *self,
+                                   const gchar          *envvar)
+{
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  g_return_if_fail (SYSPROF_IS_TRACEFD_SOURCE (self));
+
+  if (envvar == NULL)
+    envvar = "SYSPROF_TRACE_FD";
+
+  if (g_strcmp0 (priv->envvar, envvar) != 0)
+    {
+      g_free (priv->envvar);
+      priv->envvar = g_strdup (envvar);
+      g_object_notify_by_pspec (G_OBJECT (self), properties [PROP_ENVVAR]);
+    }
+}
+
+static void
+sysprof_tracefd_source_modify_spawn (SysprofSource       *source,
+                                     GSubprocessLauncher *launcher,
+                                     GPtrArray           *argv)
+{
+  SysprofTracefdSource *self = (SysprofTracefdSource *)source;
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+  gchar fdstr[12];
+  gint fd;
+
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (self));
+  g_assert (G_IS_SUBPROCESS_LAUNCHER (launcher));
+  g_assert (argv != NULL);
+  g_assert (priv->tracefd == -1);
+
+  if (-1 == (fd = sysprof_memfd_create ("[sysprof-proxy-capture]")))
+    {
+      g_warning ("Failed to create FD for tracefd capture: %s",
+                 g_strerror (errno));
+      return;
+    }
+
+  if (-1 == (priv->tracefd = dup (fd)))
+    {
+      g_warning ("Failed to duplicate tracefd for readback: %s",
+                 g_strerror (errno));
+      close (fd);
+      return;
+    }
+
+  g_snprintf (fdstr, sizeof fdstr, "%d", fd);
+  g_subprocess_launcher_setenv (launcher, priv->envvar, fdstr, TRUE);
+  g_subprocess_launcher_take_fd (launcher, fd, fd);
+}
+
+static void
+sysprof_tracefd_source_serialize (SysprofSource *source,
+                                  GKeyFile      *keyfile,
+                                  const gchar   *group)
+{
+  SysprofTracefdSource *self = (SysprofTracefdSource *)source;
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (self));
+  g_assert (keyfile != NULL);
+  g_assert (group != NULL);
+
+  g_key_file_set_string (keyfile, group, "envvar", priv->envvar);
+}
+
+static void
+sysprof_tracefd_source_deserialize (SysprofSource *source,
+                                    GKeyFile      *keyfile,
+                                    const gchar   *group)
+{
+  SysprofTracefdSource *self = (SysprofTracefdSource *)source;
+  g_autofree gchar *envvar = NULL;
+
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (self));
+  g_assert (keyfile != NULL);
+  g_assert (group != NULL);
+
+  if ((envvar = g_key_file_get_string (keyfile, group, "envvar", NULL)))
+    sysprof_tracefd_source_set_envvar (self, envvar);
+}
+
+static void
+sysprof_tracefd_source_prepare (SysprofSource *source)
+{
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (source));
+
+  sysprof_source_emit_ready (source);
+}
+
+static gboolean
+sysprof_tracefd_source_get_is_ready (SysprofSource *source)
+{
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (source));
+
+  return TRUE;
+}
+
+static void
+sysprof_tracefd_source_stop (SysprofSource *source)
+{
+  SysprofTracefdSource *self = (SysprofTracefdSource *)source;
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (self));
+
+  if (priv->writer != NULL && priv->tracefd != -1)
+    {
+      g_autoptr(SysprofCaptureReader) reader = NULL;
+
+      if ((reader = sysprof_capture_reader_new_from_fd (priv->tracefd, 0)))
+        sysprof_capture_writer_cat (priv->writer, reader, NULL);
+    }
+
+  sysprof_source_emit_finished (source);
+}
+
+static void
+sysprof_tracefd_source_set_writer (SysprofSource        *source,
+                                   SysprofCaptureWriter *writer)
+{
+  SysprofTracefdSource *self = (SysprofTracefdSource *)source;
+  SysprofTracefdSourcePrivate *priv = sysprof_tracefd_source_get_instance_private (self);
+
+  g_assert (SYSPROF_IS_TRACEFD_SOURCE (self));
+  g_assert (writer != NULL);
+
+  g_clear_pointer (&priv->writer, sysprof_capture_writer_unref);
+  priv->writer = sysprof_capture_writer_ref (writer);
+}
+
+static void
+source_iface_init (SysprofSourceInterface *iface)
+{
+  iface->deserialize = sysprof_tracefd_source_deserialize;
+  iface->get_is_ready = sysprof_tracefd_source_get_is_ready;
+  iface->modify_spawn = sysprof_tracefd_source_modify_spawn;
+  iface->prepare = sysprof_tracefd_source_prepare;
+  iface->serialize = sysprof_tracefd_source_serialize;
+  iface->set_writer = sysprof_tracefd_source_set_writer;
+  iface->stop = sysprof_tracefd_source_stop;
+}
diff --git a/src/libsysprof/sysprof-tracefd-source.h b/src/libsysprof/sysprof-tracefd-source.h
new file mode 100644
index 0000000..1dfd551
--- /dev/null
+++ b/src/libsysprof/sysprof-tracefd-source.h
@@ -0,0 +1,49 @@
+/* sysprof-tracefd-source.h
+ *
+ * Copyright 2019 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-source.h"
+
+G_BEGIN_DECLS
+
+#define SYSPROF_TYPE_TRACEFD_SOURCE (sysprof_tracefd_source_get_type())
+
+SYSPROF_AVAILABLE_IN_ALL
+G_DECLARE_DERIVABLE_TYPE (SysprofTracefdSource, sysprof_tracefd_source, SYSPROF, TRACEFD_SOURCE, GObject)
+
+struct _SysprofTracefdSourceClass
+{
+  GObjectClass parent_class;
+
+  /*< private >*/
+  gpointer _reserved[16];
+};
+
+SYSPROF_AVAILABLE_IN_ALL
+SysprofSource *sysprof_tracefd_source_new        (void);
+SYSPROF_AVAILABLE_IN_ALL
+const gchar   *sysprof_tracefd_source_get_envvar (SysprofTracefdSource *self);
+SYSPROF_AVAILABLE_IN_ALL
+void           sysprof_tracefd_source_set_envvar (SysprofTracefdSource *self,
+                                                  const gchar          *envvar);
+
+
+G_END_DECLS
diff --git a/src/libsysprof/sysprof.h b/src/libsysprof/sysprof.h
index 4ea6c12..bc23ebb 100644
--- a/src/libsysprof/sysprof.h
+++ b/src/libsysprof/sysprof.h
@@ -43,6 +43,7 @@ G_BEGIN_DECLS
 # include "sysprof-symbol-resolver.h"
 # include "sysprof-map-lookaside.h"
 # include "sysprof-selection.h"
+# include "sysprof-tracefd-source.h"
 
 #ifdef __linux__
 # include "sysprof-gjs-source.h"