flatpak: add helpers to locate flatpak installation debug dirs

The goal here is to be able to locate all of the debug directories for
active flatpak runtimes so that we can possibly decode debug libraries
from them (after verifying build-id/CRC).

src/libsysprof/meson.build

@@ -65,6 +65,7 @@ libsysprof_private_sources = [
   'binfile.c',
   'demangle.cpp',
   'elfparser.c',
+  'sysprof-flatpak.c',
   'sysprof-helpers.c',
   'sysprof-kallsyms.c',
   'sysprof-line-reader.c',

src/libsysprof/sysprof-flatpak.c

@@ -0,0 +1,136 @@
+/* sysprof-flatpak.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
+ */
+
+#include "config.h"
+
+#include <sys/utsname.h>
+
+#include "sysprof-flatpak.h"
+
+#define ETC_INSTALLATIONS_D "/etc/flatpak/installations.d"
+
+gchar **
+get_installations (void)
+{
+  GPtrArray *ret = g_ptr_array_new ();
+  g_autoptr(GDir) dir = NULL;
+
+  /* We might be running from a container, so ignore XDG_DATA_HOME as
+   * that will likely be different that what we care about the host.
+   * TODO: Can we find a way to support non-standard XDG_DATA_HOME?
+   */
+  g_ptr_array_add (ret, g_build_filename (g_get_home_dir (), ".local", "share", "flatpak", NULL));
+  g_ptr_array_add (ret, g_strdup ("/var/lib/flatpak"));
+
+  /* Now look at /etc/flatpak/installations.d for keyfiles with Path= */
+  if ((dir = g_dir_open (ETC_INSTALLATIONS_D, 0, NULL)))
+    {
+      const gchar *name;
+
+      while ((name = g_dir_read_name (dir)))
+        {
+          g_autofree gchar *path = g_build_filename (ETC_INSTALLATIONS_D, name, NULL);
+          g_autoptr(GKeyFile) kf = g_key_file_new ();
+
+          if (g_key_file_load_from_file (kf, path, G_KEY_FILE_NONE, NULL))
+            {
+              g_auto(GStrv) groups = g_key_file_get_groups (kf, NULL);
+
+              for (guint i = 0; groups[i]; i++)
+                {
+                  if (g_key_file_has_key (kf, groups[i], "Path", NULL))
+                    {
+                      gchar *val = g_key_file_get_string (kf, groups[i], "Path", NULL);
+
+                      if (val)
+                        g_ptr_array_add (ret, g_steal_pointer (&val));
+                    }
+                }
+            }
+        }
+    }
+
+  g_ptr_array_add (ret, NULL);
+  return (gchar **)g_ptr_array_free (ret, FALSE);
+}
+
+static void
+get_arch (gchar *out,
+          gsize  len)
+{
+  struct utsname u;
+  uname (&u);
+  g_strlcpy (out, u.machine, len);
+}
+
+void
+_sysprof_flatpak_debug_dirs (GPtrArray *dirs)
+{
+  g_auto(GStrv) installs = get_installations ();
+  gchar arch[32];
+
+  g_assert (dirs != NULL);
+
+  get_arch (arch, sizeof arch);
+
+  /* For each of the installations, we want to look at all of the runtimes that
+   * exist within it. Of those runtimes, we want to limit ourselves to the active
+   * version of each runtime, and see if we have a deployment for the current
+   * system arch that contains a "lib/debug" directory. We could add more, but
+   * it's just too many directories.
+   */
+
+  for (guint i = 0; installs[i]; i++)
+    {
+      g_autofree gchar *repo_dir = g_build_filename (installs[i], "runtime", NULL);
+      g_autoptr(GDir) dir = g_dir_open (repo_dir, 0, NULL);
+      const gchar *name;
+
+      if (dir == NULL)
+        continue;
+
+      while ((name = g_dir_read_name (dir)))
+        {
+          g_autofree gchar *version_dir = g_build_filename (installs[i], "runtime", name, arch, NULL);
+          g_autoptr(GDir) vdir = g_dir_open (version_dir, 0, NULL);
+          const gchar *version;
+
+          if (vdir == NULL)
+            continue;
+
+          while ((version = g_dir_read_name (vdir)))
+            {
+              g_autofree gchar *lib_debug = g_build_filename (version_dir, version, "active", "files", "lib", "debug", NULL);
+
+              if (g_file_test (lib_debug, G_FILE_TEST_EXISTS))
+                g_ptr_array_add (dirs, g_steal_pointer (&lib_debug));
+            }
+        }
+    }
+}
+
+gchar **
+sysprof_flatpak_debug_dirs (void)
+{
+  GPtrArray *dirs = g_ptr_array_new ();
+  _sysprof_flatpak_debug_dirs (dirs);
+  g_ptr_array_add (dirs, NULL);
+  return (gchar **)g_ptr_array_free (dirs, FALSE);
+}

src/libsysprof/sysprof-flatpak.h

@@ -0,0 +1,29 @@
+/* sysprof-flatpak.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 <glib.h>
+
+G_BEGIN_DECLS
+
+gchar **sysprof_flatpak_debug_dirs (void);
+
+G_END_DECLS

src/tests/meson.build

@@ -50,6 +50,13 @@ test_mountinfo = executable('test-mountinfo',
   dependencies: test_deps,
 )
 
+test_flatpak = executable('test-flatpak',
+  [ 'test-flatpak.c',
+    '../libsysprof/sysprof-flatpak.c'],
+        c_args: test_cflags,
+  dependencies: test_deps,
+)
+
 
 if get_option('enable_gtk')
 

src/tests/test-flatpak.c

@@ -0,0 +1,13 @@
+#include "sysprof-flatpak.h"
+
+gint
+main (gint   argc,
+      gchar *argv[])
+{
+  g_auto(GStrv) debug_dirs = sysprof_flatpak_debug_dirs ();
+
+  for (guint i = 0; debug_dirs[i]; i++)
+    g_print ("%s\n", debug_dirs[i]);
+
+  return 0;
+}