flatpak: Add --print-updated-env option to print environment

This is the environment needed to use flatpaks; a following commit will
hook this up to the systemd environment generator.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>

app/flatpak-main.c

@@ -50,6 +50,8 @@ static gboolean opt_default_arch;
 static gboolean opt_supported_arches;
 static gboolean opt_gl_drivers;
 static gboolean opt_list_installations;
+static gboolean opt_print_updated_env;
+static gboolean opt_print_system_only;
 static gboolean opt_user;
 static gboolean opt_system;
 static char **opt_installations;
@@ -168,6 +170,8 @@ static GOptionEntry empty_entries[] = {
   { "supported-arches", 0, 0, G_OPTION_ARG_NONE, &opt_supported_arches, N_("Print supported arches and exit"), NULL },
   { "gl-drivers", 0, 0, G_OPTION_ARG_NONE, &opt_gl_drivers, N_("Print active gl drivers and exit"), NULL },
   { "installations", 0, 0, G_OPTION_ARG_NONE, &opt_list_installations, N_("Print paths for system installations and exit"), NULL },
+  { "print-updated-env", 0, 0, G_OPTION_ARG_NONE, &opt_print_updated_env, N_("Print the updated environment needed to run flatpaks"), NULL },
+  { "print-system-only", 0, 0, G_OPTION_ARG_NONE, &opt_print_system_only, N_("Only include the system installation with --print-updated-env"), NULL },
   { NULL }
 };
 
@@ -733,6 +737,59 @@ flatpak_run (int      argc,
                       exit (EXIT_SUCCESS);
                     }
                 }
+
+              /* systemd environment generator for system and user installations.
+               * Intended to be used only from the scripts in env.d/.
+               * See `man systemd.environment-generator`. */
+              if (opt_print_updated_env)
+                {
+                  g_autoptr(GPtrArray) installations = g_ptr_array_new_with_free_func (g_free);  /* (element-type GFile) */
+                  GPtrArray *system_installation_locations;  /* (element-type GFile) */
+                  const gchar * const *xdg_data_dirs = g_get_system_data_dirs ();
+                  g_autoptr(GPtrArray) new_dirs = g_ptr_array_new_with_free_func (g_free);  /* (element-type filename) */
+                  g_autofree gchar *new_dirs_joined = NULL;
+
+                  /* Work out the set of installations we want in the environment. */
+                  if (!opt_print_system_only)
+                    {
+                      g_autoptr(GFile) home_installation_location = flatpak_get_user_base_dir_location ();
+                      g_ptr_array_add (installations, g_file_get_path (home_installation_location));
+                    }
+
+                  system_installation_locations = flatpak_get_system_base_dir_locations (NULL, &local_error);
+                  if (local_error != NULL)
+                    {
+                      g_printerr ("%s\n", local_error->message);
+                      exit (1);
+                    }
+
+                  for (gsize i = 0; i < system_installation_locations->len; i++)
+                    g_ptr_array_add (installations, g_file_get_path (system_installation_locations->pdata[i]));
+
+                  /* Get the export path for each installation, and filter out
+                   * ones which are already listed in @xdg_data_dirs. */
+                  for (gsize i = 0; i < installations->len; i++)
+                    {
+                      g_autofree gchar *share_path = g_build_filename (installations->pdata[i], "exports", "share", NULL);
+                      g_autofree gchar *share_path_with_slash = g_strconcat (share_path, "/", NULL);
+
+                      if (g_strv_contains (xdg_data_dirs, share_path) || g_strv_contains (xdg_data_dirs, share_path_with_slash))
+                        continue;
+
+                      g_ptr_array_add (new_dirs, g_steal_pointer (&share_path));
+                    }
+
+                  /* Add the rest of the existing @xdg_data_dirs to the new list. */
+                  for (gsize i = 0; xdg_data_dirs[i] != NULL; i++)
+                    g_ptr_array_add (new_dirs, g_strdup (xdg_data_dirs[i]));
+                  g_ptr_array_add (new_dirs, NULL);
+
+                  /* Print in a format suitable for a system environment generator. */
+                  new_dirs_joined = g_strjoinv (":", (gchar **) new_dirs->pdata);
+                  g_print ("XDG_DATA_DIRS=%s\n", new_dirs_joined);
+
+                  exit (EXIT_SUCCESS);
+                }
             }
 
           if (local_error)

doc/flatpak.xml

@@ -178,6 +178,28 @@
                 </para></listitem>
             </varlistentry>
 
+            <varlistentry>
+                <term><option>--print-system-only</option></term>
+
+                <listitem><para>
+                    When the <command>flatpak --print-updated-env</command>
+                    command is run, only print the environment for system
+                    flatpak installations, not including the user’s home
+                    installation.
+                </para></listitem>
+            </varlistentry>
+
+            <varlistentry>
+                <term><option>--print-updated-env</option></term>
+
+                <listitem><para>
+                    Print the set of environment variables needed to use
+                    flatpaks, amending the current set of environment variables.
+                    This is intended to be used in a systemd environment
+                    generator, and should not need to be run manually.
+                </para></listitem>
+            </varlistentry>
+
         </variablelist>
     </refsect1>
 

tests/test-basic.sh

@@ -24,7 +24,7 @@ set -euo pipefail
 # This test looks for specific localized strings.
 export LC_ALL=C
 
-echo "1..10"
+echo "1..11"
 
 ${FLATPAK} --version > version_out
 
@@ -47,6 +47,16 @@ assert_streq `head -1 arches` `cat arch`
 
 ok "default arch"
 
+${FLATPAK} --print-updated-env > updated_env
+${FLATPAK} --print-updated-env --print-system-only > updated_env_system
+
+assert_file_has_content updated_env "exports/share"
+assert_file_has_content updated_env "^XDG_DATA_DIRS="
+assert_file_has_content updated_env_system "exports/share"
+assert_file_has_content updated_env_system "^XDG_DATA_DIRS="
+
+ok "print updated env"
+
 ${FLATPAK} --gl-drivers > drivers
 
 assert_file_has_content drivers "^default$";

tests/test-completion.sh

@@ -69,6 +69,8 @@ ${FLATPAK} complete "flatpak --" 10 "--" | sort > complete_out
 --installation=
 --installations 
 --ostree-verbose 
+--print-system-only 
+--print-updated-env 
 --supported-arches 
 --system 
 --user