libsysprof: add symbol resolver that can resolve from capture file

If the capture file has an embedded __symbols__ file within it, we can
try to resolve the function names from the data embedded within that
virtual file.

src/libsysprof/meson.build

@@ -3,6 +3,7 @@ libsysprof_c_args = [ '-DSYSPROF_COMPILATION' ]
 libsysprof_public_sources = [
   'sysprof-callgraph-profile.c',
   'sysprof-capture-gobject.c',
+  'sysprof-capture-symbol-resolver.c',
   'sysprof-elf-symbol-resolver.c',
   'sysprof-hostinfo-source.c',
   'sysprof-jitmap-symbol-resolver.c',
@@ -25,6 +26,7 @@ libsysprof_public_sources = [
 libsysprof_public_headers = [
   'sysprof-callgraph-profile.h',
   'sysprof-capture-gobject.h',
+  'sysprof-capture-symbol-resolver.h',
   'sysprof-elf-symbol-resolver.h',
   'sysprof-hostinfo-source.h',
   'sysprof-jitmap-symbol-resolver.h',

src/libsysprof/sysprof-capture-symbol-resolver.c

@@ -0,0 +1,135 @@
+/* sysprof-capture-symbol-resolver.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-capture-symbol-resolver"
+
+#include "config.h"
+
+#include <unistd.h>
+
+#include "sysprof-capture-symbol-resolver.h"
+#include "sysprof-platform.h"
+#include "sysprof-private.h"
+#include "sysprof-symbol-map.h"
+
+/**
+ * SECTION:sysprof-capture-symbol-resolver:
+ * @title: SysprofCaptureSymbolResolver
+ * @short_description: resolve symbols from embedded data within the capture
+ *
+ * This looks for an embedded file "__symbols__" in the capture and tries to
+ * decode them using the data stored within that file.
+ *
+ * This is useful when moving capture files between machines as it will allow
+ * the viewer machine to get access to the symbols without having to copy them
+ * to the local system.
+ *
+ * Since: 3.34
+ */
+
+struct _SysprofCaptureSymbolResolver
+{
+  GObject           parent_instance;
+  SysprofSymbolMap *map;
+};
+
+static void symbol_resolver_iface_init (SysprofSymbolResolverInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (SysprofCaptureSymbolResolver, sysprof_capture_symbol_resolver, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (SYSPROF_TYPE_SYMBOL_RESOLVER, symbol_resolver_iface_init))
+
+static void
+sysprof_capture_symbol_resolver_finalize (GObject *object)
+{
+  SysprofCaptureSymbolResolver *self = (SysprofCaptureSymbolResolver *)object;
+
+  g_clear_pointer (&self->map, sysprof_symbol_map_free);
+
+  G_OBJECT_CLASS (sysprof_capture_symbol_resolver_parent_class)->finalize (object);
+}
+
+static void
+sysprof_capture_symbol_resolver_class_init (SysprofCaptureSymbolResolverClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = sysprof_capture_symbol_resolver_finalize;
+}
+
+static void
+sysprof_capture_symbol_resolver_init (SysprofCaptureSymbolResolver *self)
+{
+  self->map = sysprof_symbol_map_new ();
+}
+
+SysprofSymbolResolver *
+sysprof_capture_symbol_resolver_new (void)
+{
+  return g_object_new (SYSPROF_TYPE_CAPTURE_SYMBOL_RESOLVER, NULL);
+}
+
+static void
+sysprof_capture_symbol_resolver_load (SysprofSymbolResolver *resolver,
+                                      SysprofCaptureReader  *reader)
+{
+  SysprofCaptureSymbolResolver *self = (SysprofCaptureSymbolResolver *)resolver;
+  g_autoptr(GError) error = NULL;
+  gint byte_order;
+  gint fd;
+
+  g_assert (SYSPROF_IS_CAPTURE_SYMBOL_RESOLVER (self));
+  g_assert (reader != NULL);
+
+  byte_order = sysprof_capture_reader_get_byte_order (reader);
+
+  if (-1 == (fd = sysprof_memfd_create ("[symbol-decoder]")))
+    return;
+
+  if (sysprof_capture_reader_read_file_fd (reader, "__symbols__", fd))
+    sysprof_symbol_map_deserialize (self->map, byte_order, fd);
+
+  close (fd);
+}
+
+gchar *
+sysprof_capture_symbol_resolver_resolve_with_context (SysprofSymbolResolver *resolver,
+                                                      guint64                time,
+                                                      GPid                   pid,
+                                                      SysprofAddressContext  context,
+                                                      SysprofCaptureAddress  address,
+                                                      GQuark                *tag)
+{
+  SysprofCaptureSymbolResolver *self = (SysprofCaptureSymbolResolver *)resolver;
+  const gchar *name;
+
+  g_assert (SYSPROF_IS_CAPTURE_SYMBOL_RESOLVER (self));
+
+  if ((name = sysprof_symbol_map_lookup (self->map, time, pid, address, tag)))
+    return g_strdup (name);
+
+  return NULL;
+}
+
+static void
+symbol_resolver_iface_init (SysprofSymbolResolverInterface *iface)
+{
+  iface->load = sysprof_capture_symbol_resolver_load;
+  iface->resolve_with_context = sysprof_capture_symbol_resolver_resolve_with_context;
+}

src/libsysprof/sysprof-capture-symbol-resolver.h

@@ -0,0 +1,33 @@
+/* sysprof-capture-symbol-resolver.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-symbol-resolver.h"
+
+G_BEGIN_DECLS
+
+#define SYSPROF_TYPE_CAPTURE_SYMBOL_RESOLVER (sysprof_capture_symbol_resolver_get_type())
+
+G_DECLARE_FINAL_TYPE (SysprofCaptureSymbolResolver, sysprof_capture_symbol_resolver, SYSPROF, CAPTURE_SYMBOL_RESOLVER, GObject)
+
+SysprofSymbolResolver *sysprof_capture_symbol_resolver_new (void);
+
+G_END_DECLS

src/libsysprof/sysprof.h

@@ -26,6 +26,7 @@ G_BEGIN_DECLS
 
 # include "sysprof-callgraph-profile.h"
 # include "sysprof-capture-gobject.h"
+# include "sysprof-capture-symbol-resolver.h"
 # include "sysprof-elf-symbol-resolver.h"
 # include "sysprof-jitmap-symbol-resolver.h"
 # include "sysprof-kernel-symbol-resolver.h"