From d01169e18035d062abb8e19fa2e7262769c08777 Mon Sep 17 00:00:00 2001 From: Ray Strode Date: Feb 18 2015 22:34:14 +0000 Subject: daemon: add wrapper for launching X session This commit adds a utility for launching an X server and session together. This utility works a lot like xinit, but makes use of modern X features (like -displayfd) and has GDM specific integration (like reading from gdm configuration, and optionally running through /etc/gdm/Xsession) The eventual idea is to get the main GDM code out of the X server launching business and instead farm the logic off to an unprivileged helper that gets run within the logind session of the user. https://bugzilla.gnome.org/show_bug.cgi?id=744764 --- diff --git a/daemon/Makefile.am b/daemon/Makefile.am index 1f2feb4..bbd0252 100644 --- a/daemon/Makefile.am +++ b/daemon/Makefile.am @@ -112,6 +112,7 @@ test_session_client_LDADD = \ libexec_PROGRAMS = \ gdm-session-worker \ gdm-wayland-session \ + gdm-x-session \ $(NULL) gdm_session_worker_SOURCES = \ @@ -155,6 +156,20 @@ gdm_wayland_session_SOURCES = \ gdm-wayland-session.c \ $(NULL) +gdm_x_session_LDADD = \ + $(top_builddir)/common/libgdmcommon.la \ + $(GTK_LIBS) \ + $(COMMON_LIBS) \ + $(SYSTEMD_LIBS) \ + $(XLIB_LIBS) \ + $(NULL) + +gdm_x_session_SOURCES = \ + gdm-manager-glue.h \ + gdm-manager-glue.c \ + gdm-x-session.c \ + $(NULL) + if HAVE_LIBAUDIT gdm_session_worker_SOURCES += gdm-session-linux-auditor.h \ gdm-session-linux-auditor.c diff --git a/daemon/gdm-x-session.c b/daemon/gdm-x-session.c new file mode 100644 index 0000000..e97cfff --- /dev/null +++ b/daemon/gdm-x-session.c @@ -0,0 +1,768 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- + * + * Copyright (C) 2015 Red Hat, Inc. + * + * 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 2, 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, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ +#include "config.h" + +#include +#include + +#include "gdm-common.h" +#include "gdm-settings-direct.h" +#include "gdm-settings-keys.h" +#include "gdm-log.h" + +#include "gdm-manager-glue.h" + +#include +#include +#include +#include +#include +#include +#include + +#define DISPLAY_FILENO (STDERR_FILENO + 1) +#define BUS_ADDRESS_FILENO (DISPLAY_FILENO + 1) + +#define DBUS_DAEMON BINDIR "/dbus-daemon" + +typedef struct +{ + GdmSettings *settings; + GCancellable *cancellable; + + GSubprocess *x_subprocess; + char *auth_file; + char *display_name; + + GSubprocess *bus_subprocess; + char *bus_address; + + GSubprocess *session_subprocess; + char *session_command; + int session_exit_status; + + GMainLoop *main_loop; + + guint32 debug_enabled : 1; +} State; + +static FILE * +create_auth_file (char **filename) +{ + char *auth_dir = NULL; + char *auth_file = NULL; + int fd; + FILE *fp = NULL; + + auth_dir = g_build_filename (g_get_user_runtime_dir (), + "gdm", + NULL); + + g_mkdir_with_parents (auth_dir, 0711); + auth_file = g_build_filename (auth_dir, "Xauthority", NULL); + g_clear_pointer (&auth_dir, g_free); + + fd = g_open (auth_file, O_RDWR | O_CREAT | O_TRUNC, 0700); + + if (fd < 0) { + g_debug ("could not open %s to store auth cookie: %m", + auth_file); + g_clear_pointer (&auth_file, g_free); + goto out; + } + + fp = fdopen (fd, "w+"); + + if (fp == NULL) { + g_debug ("could not set up stream for auth cookie file: %m"); + g_clear_pointer (&auth_file, g_free); + close (fd); + goto out; + } + + *filename = auth_file; +out: + return fp; +} + +static char * +prepare_auth_file (void) +{ + FILE *fp = NULL; + char *filename = NULL; + GError *error = NULL; + gboolean prepared = FALSE; + Xauth auth_entry = { 0 }; + char localhost[HOST_NAME_MAX + 1] = ""; + + g_debug ("Preparing auth file for X server"); + + fp = create_auth_file (&filename); + + if (fp == NULL) { + return NULL; + } + + if (gethostname (localhost, HOST_NAME_MAX) < 0) { + strncpy (localhost, "localhost", sizeof (localhost) - 1); + } + + auth_entry.family = FamilyLocal; + auth_entry.address = localhost; + auth_entry.address_length = strlen (auth_entry.address); + auth_entry.name = "MIT-MAGIC-COOKIE-1"; + auth_entry.name_length = strlen (auth_entry.name); + + auth_entry.data_length = 16; + auth_entry.data = gdm_generate_random_bytes (auth_entry.data_length, &error); + + if (error != NULL) { + goto out; + } + + if (!XauWriteAuth (fp, &auth_entry) || fflush (fp) == EOF) { + goto out; + } + + auth_entry.family = FamilyWild; + if (!XauWriteAuth (fp, &auth_entry) || fflush (fp) == EOF) { + goto out; + } + + prepared = TRUE; + +out: + g_clear_pointer (&auth_entry.data, g_free); + g_clear_pointer (&fp, fclose); + + if (!prepared) { + g_clear_pointer (&filename, g_free); + } + + return filename; +} + +static void +on_x_server_finished (GSubprocess *subprocess, + GAsyncResult *result, + State *state) +{ + gboolean cancelled; + + cancelled = !g_subprocess_wait_finish (subprocess, result, NULL); + + if (cancelled) { + goto out; + } + + if (g_subprocess_get_if_exited (subprocess)) { + int exit_status; + + exit_status = g_subprocess_get_exit_status (subprocess); + + g_debug ("X server exited with status %d", exit_status); + } else { + int signal_number; + + signal_number = g_subprocess_get_term_sig (subprocess); + g_debug ("X server was killed with status %d", signal_number); + } + +out: + g_clear_object (&state->x_subprocess); + g_main_loop_quit (state->main_loop); +} + +static gboolean +spawn_x_server (State *state, + gboolean allow_remote_connections, + GCancellable *cancellable) +{ + GPtrArray *arguments; + GSubprocessLauncher *launcher; + GSubprocess *subprocess; + GInputStream *input_stream; + GDataInputStream *data_stream; + GError *error = NULL; + + char *auth_file; + gboolean is_running = FALSE; + int ret; + int pipe_fds[2]; + char *display_fd_string = NULL; + char *vt_string = NULL; + char *display_number; + gsize display_number_size; + + auth_file = prepare_auth_file (); + + g_debug ("Running X server"); + + ret = g_unix_open_pipe (pipe_fds, FD_CLOEXEC, &error); + + if (!ret) { + g_debug ("could not open pipe: %s", error->message); + goto out; + } + + arguments = g_ptr_array_new (); + launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_STDIN_INHERIT); + g_subprocess_launcher_setenv (launcher, "DBUS_SESSION_BUS_ADDRESS", state->bus_address, TRUE); + g_subprocess_launcher_take_fd (launcher, pipe_fds[1], DISPLAY_FILENO); + + if (g_getenv ("XDG_VTNR") != NULL) { + int vt; + + vt = atoi (g_getenv ("XDG_VTNR")); + + if (vt > 0 && vt < 64) { + vt_string = g_strdup_printf ("vt%d", vt); + } + } + + display_fd_string = g_strdup_printf ("%d", DISPLAY_FILENO); + + g_ptr_array_add (arguments, X_SERVER); + + if (vt_string != NULL) { + g_ptr_array_add (arguments, vt_string); + } + + g_ptr_array_add (arguments, "-displayfd"); + g_ptr_array_add (arguments, display_fd_string); + + g_ptr_array_add (arguments, "-auth"); + g_ptr_array_add (arguments, auth_file); + + if (!allow_remote_connections) { + g_ptr_array_add (arguments, "-nolisten"); + g_ptr_array_add (arguments, "tcp"); + } + + g_ptr_array_add (arguments, "-background"); + g_ptr_array_add (arguments, "none"); + + g_ptr_array_add (arguments, "-noreset"); + g_ptr_array_add (arguments, "-keeptty"); + + g_ptr_array_add (arguments, "-verbose"); + if (state->debug_enabled) { + g_ptr_array_add (arguments, "7"); + } else { + g_ptr_array_add (arguments, "3"); + } + + if (state->debug_enabled) { + g_ptr_array_add (arguments, "-core"); + } + g_ptr_array_add (arguments, NULL); + + subprocess = g_subprocess_launcher_spawnv (launcher, + (const char * const *) arguments->pdata, + &error); + g_free (display_fd_string); + g_clear_object (&launcher); + g_ptr_array_free (arguments, TRUE); + + if (subprocess == NULL) { + g_debug ("could not start X server: %s", error->message); + goto out; + } + + input_stream = g_unix_input_stream_new (pipe_fds[0], TRUE); + data_stream = g_data_input_stream_new (input_stream); + g_clear_object (&input_stream); + + display_number = g_data_input_stream_read_line (data_stream, + &display_number_size, + cancellable, + &error); + + if (error != NULL) { + g_debug ("could not read display string from X server: %s", error->message); + goto out; + } + + if (display_number == NULL) { + g_debug ("X server did not write display string"); + goto out; + } + + state->display_name = g_strdup_printf (":%s", display_number); + g_clear_pointer (&display_number, g_free); + + state->auth_file = g_strdup (auth_file); + state->x_subprocess = g_object_ref (subprocess); + + g_subprocess_wait_async (state->x_subprocess, + cancellable, + (GAsyncReadyCallback) + on_x_server_finished, + state); + + is_running = TRUE; +out: + g_clear_pointer (&auth_file, g_free); + g_clear_object (&data_stream); + g_clear_object (&subprocess); + g_clear_object (&launcher); + g_clear_error (&error); + + return is_running; +} + +static void +on_bus_finished (GSubprocess *subprocess, + GAsyncResult *result, + State *state) +{ + gboolean cancelled; + + cancelled = !g_subprocess_wait_finish (subprocess, result, NULL); + + if (cancelled) { + goto out; + } + + if (g_subprocess_get_if_exited (subprocess)) { + int exit_status; + + exit_status = g_subprocess_get_exit_status (subprocess); + + g_debug ("message bus exited with status %d", exit_status); + } else { + int signal_number; + + signal_number = g_subprocess_get_term_sig (subprocess); + g_debug ("message bus was killed with status %d", signal_number); + } + +out: + g_clear_object (&state->bus_subprocess); + g_main_loop_quit (state->main_loop); +} + +static gboolean +spawn_bus (State *state, + GCancellable *cancellable) +{ + GPtrArray *arguments; + GSubprocessLauncher *launcher; + GSubprocess *subprocess; + GInputStream *input_stream; + GDataInputStream *data_stream; + GError *error = NULL; + char *bus_address_fd_string; + char *bus_address; + gsize bus_address_size; + + gboolean is_running = FALSE; + int ret; + int pipe_fds[2]; + + g_debug ("Running session message bus"); + + ret = g_unix_open_pipe (pipe_fds, FD_CLOEXEC, &error); + + if (!ret) { + g_debug ("could not open pipe: %s", error->message); + goto out; + } + + arguments = g_ptr_array_new (); + launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_NONE); + g_subprocess_launcher_take_fd (launcher, pipe_fds[1], BUS_ADDRESS_FILENO); + + bus_address_fd_string = g_strdup_printf ("%d", BUS_ADDRESS_FILENO); + + g_ptr_array_add (arguments, DBUS_DAEMON); + + g_ptr_array_add (arguments, "--print-address"); + g_ptr_array_add (arguments, bus_address_fd_string); + g_ptr_array_add (arguments, "--session"); + g_ptr_array_add (arguments, NULL); + + subprocess = g_subprocess_launcher_spawnv (launcher, + (const char * const *) arguments->pdata, + &error); + g_free (bus_address_fd_string); + g_clear_object (&launcher); + g_ptr_array_free (arguments, TRUE); + + if (subprocess == NULL) { + g_debug ("could not start X server: %s", error->message); + goto out; + } + + input_stream = g_unix_input_stream_new (pipe_fds[0], TRUE); + data_stream = g_data_input_stream_new (input_stream); + g_clear_object (&input_stream); + + bus_address = g_data_input_stream_read_line (data_stream, + &bus_address_size, + cancellable, + &error); + + if (error != NULL) { + g_debug ("could not read address from session message bus: %s", error->message); + goto out; + } + + if (bus_address == NULL) { + g_debug ("session message bus did not write address"); + goto out; + } + + state->bus_address = bus_address; + + state->bus_subprocess = g_object_ref (subprocess); + + g_subprocess_wait_async (state->bus_subprocess, + cancellable, + (GAsyncReadyCallback) + on_bus_finished, + state); + + is_running = TRUE; +out: + g_clear_object (&data_stream); + g_clear_object (&subprocess); + g_clear_object (&launcher); + g_clear_error (&error); + + return is_running; +} + + +static void +on_session_finished (GSubprocess *subprocess, + GAsyncResult *result, + State *state) +{ + gboolean cancelled; + + cancelled = !g_subprocess_wait_finish (subprocess, result, NULL); + + if (cancelled) { + goto out; + } + + if (g_subprocess_get_if_exited (subprocess)) { + int exit_status; + + exit_status = g_subprocess_get_exit_status (subprocess); + + g_debug ("session exited with status %d", exit_status); + + state->session_exit_status = exit_status; + } else { + int signal_number; + + signal_number = g_subprocess_get_term_sig (subprocess); + g_debug ("session was killed with status %d", signal_number); + } + +out: + g_clear_object (&state->session_subprocess); + g_main_loop_quit (state->main_loop); +} + +static gboolean +spawn_session (State *state, + gboolean run_script, + GCancellable *cancellable) +{ + GSubprocessLauncher *launcher; + GSubprocess *subprocess; + GError *error = NULL; + gboolean is_running = FALSE; + const char *vt; + + g_debug ("Running X session"); + + launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_NONE); + + g_subprocess_launcher_setenv (launcher, "DISPLAY", state->display_name, TRUE); + g_subprocess_launcher_setenv (launcher, "XAUTHORITY", state->auth_file, TRUE); + + vt = g_getenv ("XDG_VTNR"); + + if (vt != NULL) { + g_subprocess_launcher_setenv (launcher, "WINDOWPATH", g_getenv ("XDG_VTNR"), TRUE); + } + + if (run_script) { + subprocess = g_subprocess_launcher_spawn (launcher, + &error, + GDMCONFDIR "/Xsession", + state->session_command, + NULL); + } else { + int ret; + char **argv; + + ret = g_shell_parse_argv (state->session_command, + NULL, + &argv, + &error); + + if (!ret) { + g_debug ("could not parse session arguments: %s", error->message); + goto out; + } + subprocess = g_subprocess_launcher_spawnv (launcher, + (const char * const *) argv, + &error); + g_strfreev (argv); + } + + if (subprocess == NULL) { + g_debug ("could not start session: %s", error->message); + goto out; + } + + state->session_subprocess = g_object_ref (subprocess); + + g_subprocess_wait_async (state->session_subprocess, + cancellable, + (GAsyncReadyCallback) + on_session_finished, + state); + + is_running = TRUE; +out: + g_clear_object (&subprocess); + return is_running; +} + +static void +signal_subprocesses (State *state) +{ + if (state->session_subprocess != NULL) { + g_subprocess_send_signal (state->session_subprocess, SIGTERM); + } + + if (state->bus_subprocess != NULL) { + g_subprocess_send_signal (state->bus_subprocess, SIGTERM); + } + + if (state->x_subprocess != NULL) { + g_subprocess_send_signal (state->x_subprocess, SIGTERM); + } +} + +static void +wait_on_subprocesses (State *state) +{ + if (state->x_subprocess != NULL) { + g_subprocess_wait (state->x_subprocess, NULL, NULL); + } + + if (state->bus_subprocess != NULL) { + g_subprocess_wait (state->bus_subprocess, NULL, NULL); + } + + if (state->session_subprocess != NULL) { + g_subprocess_wait (state->session_subprocess, NULL, NULL); + } +} + +static gboolean +register_display (State *state, + GCancellable *cancellable) +{ + GdmDBusManager *manager; + GError *error = NULL; + gboolean registered = FALSE; + GVariantBuilder details; + + manager = gdm_dbus_manager_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM, + G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES | + G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS, + "org.gnome.DisplayManager", + "/org/gnome/DisplayManager/Manager", + cancellable, + &error); + + if (!manager) { + g_debug ("could not contact display manager: %s", error->message); + g_error_free (error); + goto out; + } + + g_variant_builder_init (&details, G_VARIANT_TYPE ("a{ss}")); + g_variant_builder_add (&details, "{ss}", "session-type", "x11"); + g_variant_builder_add (&details, "{ss}", "x11-display-name", state->display_name); + + registered = gdm_dbus_manager_call_register_display_sync (manager, + g_variant_builder_end (&details), + cancellable, + &error); + if (error != NULL) { + g_debug ("Could not register display: %s", error->message); + g_error_free (error); + } + +out: + g_clear_object (&manager); + return registered; +} + +static void +init_state (State **state) +{ + static State state_allocation; + + *state = &state_allocation; +} + +static void +clear_state (State **out_state) +{ + State *state = *out_state; + + g_clear_object (&state->cancellable); + g_clear_object (&state->session_subprocess); + g_clear_object (&state->x_subprocess); + g_clear_pointer (&state->auth_file, g_free); + g_clear_pointer (&state->display_name, g_free); + g_clear_pointer (&state->main_loop, g_main_loop_unref); + *out_state = NULL; +} + +static gboolean +on_sigterm (State *state) +{ + g_cancellable_cancel (state->cancellable); + + if (g_main_loop_is_running (state->main_loop)) { + g_main_loop_quit (state->main_loop); + } + + return G_SOURCE_CONTINUE; +} + +int +main (int argc, + char **argv) +{ + State *state; + GOptionContext *context; + static char **args = NULL; + static gboolean run_script = FALSE; + static gboolean allow_remote_connections = FALSE; + gboolean debug = FALSE; + gboolean ret; + int exit_status = EX_OK; + static GOptionEntry entries [] = { + { "run-script", 'r', 0, G_OPTION_ARG_NONE, &run_script, N_("Run program through /etc/gdm/Xsession wrapper script"), NULL }, + { "allow-remote-connections", 'a', 0, G_OPTION_ARG_NONE, &allow_remote_connections, N_("Listen on TCP socket"), NULL }, + { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, "", "" }, + { NULL } + }; + + bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR); + textdomain (GETTEXT_PACKAGE); + setlocale (LC_ALL, ""); + + gdm_log_init (); + + context = g_option_context_new (_("GNOME Display Manager X Session Launcher")); + g_option_context_add_main_entries (context, entries, NULL); + + g_option_context_parse (context, &argc, &argv, NULL); + g_option_context_free (context); + + if (args == NULL || args[0] == NULL || args[1] != NULL) { + g_warning ("gdm-x-session takes one argument (the session)"); + exit_status = EX_USAGE; + goto out; + } + + init_state (&state); + + state->session_command = args[0]; + + state->settings = gdm_settings_new (); + ret = gdm_settings_direct_init (state->settings, DATADIR "/gdm/gdm.schemas", "/"); + + if (!ret) { + g_printerr ("Unable to initialize settings"); + exit_status = EX_DATAERR; + goto out; + } + + gdm_settings_direct_get_boolean (GDM_KEY_DEBUG, &debug); + state->debug_enabled = debug; + + gdm_log_set_debug (debug); + + state->main_loop = g_main_loop_new (NULL, FALSE); + state->cancellable = g_cancellable_new (); + + g_unix_signal_add (SIGTERM, (GSourceFunc) on_sigterm, state); + + ret = spawn_x_server (state, allow_remote_connections, state->cancellable); + + if (!ret) { + g_printerr ("Unable to run X server"); + exit_status = EX_SOFTWARE; + goto out; + } + + ret = spawn_bus (state, state->cancellable); + + if (!ret) { + g_printerr ("Unable to run session message bus"); + exit_status = EX_SOFTWARE; + goto out; + } + + ret = register_display (state, state->cancellable); + + if (!ret) { + g_printerr ("Unable to register display with display manager"); + exit_status = EX_SOFTWARE; + goto out; + } + + ret = spawn_session (state, run_script, state->cancellable); + + if (!ret) { + g_printerr ("Unable to run session"); + exit_status = EX_SOFTWARE; + goto out; + } + + g_main_loop_run (state->main_loop); + + /* Only use exit status of session if we're here because it exit */ + + if (state->session_subprocess == NULL) { + exit_status = state->session_exit_status; + } + +out: + signal_subprocesses (state); + wait_on_subprocesses (state); + clear_state (&state); + + return exit_status; +} diff --git a/utils/Makefile.am b/utils/Makefile.am index ca70a3e..ae3cc01 100644 --- a/utils/Makefile.am +++ b/utils/Makefile.am @@ -7,6 +7,8 @@ AM_CPPFLAGS = \ -I$(top_builddir) \ -I$(top_srcdir)/common \ -I$(top_builddir)/common \ + -DDATADIR=\"$(datadir)\" \ + -DGDMCONFDIR=\"$(gdmconfdir)\" \ -DLOCALSTATEDIR=\""$(localstatedir)"\" \ -DGDM_SCREENSHOT_DIR=\""$(GDM_SCREENSHOT_DIR)"\"\ -DGNOMELOCALEDIR=\""$(datadir)/locale"\" \ @@ -29,9 +31,6 @@ bin_PROGRAMS = \ gdm-screenshot \ $(NULL) -gdmflexiserver_SOURCES = \ - gdmflexiserver.c \ - $(NULL) gdmflexiserver_LDADD = \ $(top_builddir)/common/libgdmcommon.la \ $(GTK_LIBS) \