1 /* GStreamer base utils library plugin install support for applications
2 * Copyright (C) 2007 Tim-Philipp Müller <tim centricular net>
3 * Copyright (C) 2006 Ryan Lortie <desrt desrt ca>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 02111-1307, USA.
22 * SECTION:gstpbutilsinstallplugins
23 * @short_description: Missing plugin installation support for applications
26 * <title>Overview</title>
28 * Using this API, applications can request the installation of missing
29 * GStreamer plugins. These may be missing decoders/demuxers or encoders/muxers
30 * for a certain format, sources or sinks for a certain URI protocol
31 * (e.g. 'http'), or certain elements known by their element factory name
35 * Whether plugin installation is supported or not depends on the operating
36 * system and/or distribution in question. The vendor of the operating system
37 * needs to make sure the necessary hooks and mechanisms are in place for
38 * plugin installation to work. See below for more detailed information.
41 * From the application perspective, plugin installation is usually triggered
45 * when the application itself has found that it wants or needs to install a
49 * when the application has been notified by an element (such as playbin or
50 * decodebin) that one or more plugins are missing <emphasis>and</emphasis>
51 * the application has decided that it wants to install one or more of those
56 * <title>Detail Strings</title>
58 * The install functions in this section all take one or more 'detail strings'.
59 * These detail strings contain information about the type of plugin that
60 * needs to be installed (decoder, encoder, source, sink, or named element),
61 * and some additional information such GStreamer version used and a
62 * human-readable description of the component to install for user dialogs.
65 * Applications should not concern themselves with the composition of the
66 * string itself. They should regard the string as if it was a shared secret
67 * between GStreamer and the plugin installer application.
70 * Detail strings can be obtained using the function
71 * gst_missing_plugin_message_get_installer_detail() on a missing-plugin
72 * message. Such a message will either have been found by the application on
73 * a pipeline's #GstBus, or the application will have created it itself using
74 * gst_missing_element_message_new(), gst_missing_decoder_message_new(),
75 * gst_missing_encoder_message_new(), gst_missing_uri_sink_message_new(), or
76 * gst_missing_uri_source_message_new().
78 * <title>Plugin Installation from the Application Perspective</title>
80 * For each GStreamer element/plugin/component that should be installed, the
81 * application needs one of those 'installer detail' string mentioned in the
82 * previous section. This string can be obtained, as already mentioned above,
83 * from a missing-plugin message using the function
84 * gst_missing_plugin_message_get_installer_detail(). The missing-plugin
85 * message is either posted by another element and then found on the bus
86 * by the application, or the application has created it itself as described
90 * The application will then call gst_install_plugins_async(), passing a
91 * #NULL-terminated array of installer detail strings, and a function that
92 * should be called when the installation of the plugins has finished
93 * (successfully or not). Optionally, a #GstInstallPluginsContext created
94 * with gst_install_plugins_context_new() may be passed as well. This way
95 * additional optional arguments like the application window's XID can be
96 * passed to the external installer application.
99 * gst_install_plugins_async() will return almost immediately, with the
100 * return code indicating whether plugin installation was started or not.
101 * If the necessary hooks for plugin installation are in place and an
102 * external installer application has in fact been called, the passed in
103 * function will be called with a result code as soon as the external installer
104 * has finished. If the result code indicates that new plugins have been
105 * installed, the application will want to call gst_update_registry() so the
106 * run-time plugin registry is updated and the new plugins are made available
107 * to the application.
109 * A Gtk/GLib main loop must be running in order for the result function to
110 * be called when the external installer has finished. If this is not the case,
111 * make sure to regularly call
113 * g_main_context_iteration (NULL,FALSE);
118 * <title>Plugin Installation from the Vendor/Distribution Perspective</title>
120 * <emphasis>1. Installer hook</emphasis>
123 * When GStreamer applications initiate plugin installation via
124 * gst_install_plugins_async() or gst_install_plugins_sync(), a pre-defined
125 * helper application will be called.
128 * The exact path of the helper application to be called is set at compile
129 * time, usually by the <literal>./configure</literal> script based on the
130 * install prefix. For a normal package build into the <literal>/usr</literal>
131 * prefix, this will usually default to
132 * <filename>/usr/libexec/gst-install-plugins-helper</filename> or
133 * <filename>/usr/lib/gst-install-plugins-helper</filename>.
136 * Vendors/distros who want to support GStreamer plugin installation should
137 * either provide such a helper script/application or use the
138 * <literal>./configure</literal> option
139 * <literal>--with-install-plugins-helper=/path/to/installer</literal> to
140 * make GStreamer call an installer of their own directly.
143 * It is strongly recommended that vendors provide a small helper application
144 * as interlocutor to the real installer though, even more so if command line
145 * argument munging is required to transform the command line arguments
146 * passed by GStreamer to the helper application into arguments that are
147 * understood by the reeal installer.
150 * The helper application path defined at compile time can be overriden at
151 * runtime by setting the <envar>GST_INSTALL_PLUGINS_HELPER</envar>
152 * environment variable. This can be useful for testing/debugging purposes.
155 * <emphasis>2. Arguments passed to the install helper</emphasis>
158 * GStreamer will pass the following arguments to the install helper (this is
159 * in addition to the path of the executable itself, which is by convention
163 * none to many optional arguments in the form of
164 * <literal>--foo-bar=val</literal>. Example:
165 * <literal>--transient-for=XID</literal> where XID is the X Window ID of
166 * the main window of the calling application (so the installer can make
167 * itself transient to that window). Unknown optional arguments should
168 * be ignored by the installer.
171 * one 'installer detail string' argument for each plugin to be installed;
172 * these strings will have a <literal>gstreamer</literal> prefix; the
173 * exact format of the detail string is explained below
178 * <emphasis>3. Detail string describing the missing plugin</emphasis>
181 * The string is in UTF-8 encoding and is made up of several fields, separated
182 * by '|' characters (but neither the first nor the last character is a '|').
186 * plugin system identifier, ie. "gstreamer"
188 * This identifier determines the format of the rest of the detail string.
189 * Automatic plugin installers should not process detail strings with
190 * unknown identifiers. This allows other plugin-based libraries to use
191 * the same mechanism for their automatic plugin installation needs, or
192 * for the format to be changed should it turn out to be insufficient.
195 * plugin system version, e.g. "0.10"
197 * This is required so that when there is a GStreamer-0.12 or GStreamer-1.0
198 * at some point in future, the different major versions can still co-exist
199 * and use the same plugin install mechanism in the same way.
202 * application identifier, e.g. "totem"
204 * This may also be in the form of "pid/12345" if the program name can't
205 * be obtained for some reason.
208 * human-readable localised description of the required component,
209 * e.g. "Vorbis audio decoder"
212 * identifier string for the required component (see below for details about
213 * how to map this to the package/plugin that needs installing), e.g.
216 * urisource-$(PROTOCOL_REQUIRED), e.g. urisource-http or urisource-mms
219 * element-$(ELEMENT_REQUIRED), e.g. element-ffmpegcolorspace
222 * decoder-$(CAPS_REQUIRED), e.g. (do read below for more details!):
224 * <listitem><para>decoder-audio/x-vorbis</para></listitem>
225 * <listitem><para>decoder-application/ogg</para></listitem>
226 * <listitem><para>decoder-audio/mpeg, mpegversion=(int)4</para></listitem>
227 * <listitem><para>decoder-video/mpeg, systemstream=(boolean)true, mpegversion=(int)2</para></listitem>
231 * encoder-$(CAPS_REQUIRED), e.g. encoder-audio/x-vorbis
236 * optional further fields not yet specified
241 * An entire ID string might then look like this, for example:
243 * gstreamer|0.10|totem|Vorbis audio decoder|decoder-audio/x-vorbis
247 * Plugin installers parsing this ID string should expect further fields also
248 * separated by '|' symbols and either ignore them, warn the user, or error
249 * out when encountering them.
252 * Those unfamiliar with the GStreamer 'caps' system should note a few things
253 * about the caps string used in the above decoder/encoder case:
256 * the first part ("video/mpeg") of the caps string is a GStreamer media
257 * type and <emphasis>not</emphasis> a MIME type. Wherever possible, the
258 * GStreamer media type will be the same as the corresponding MIME type,
259 * but often it is not.
262 * a caps string may or may not have additional comma-separated fields
263 * of various types (as seen in the examples above)
266 * the caps string of a 'required' component (as above) will always have
267 * fields with fixed values, whereas an introspected string (see below)
268 * may have fields with non-fixed values. Compare for example:
271 * <literal>audio/mpeg, mpegversion=(int)4</literal> vs.
272 * <literal>audio/mpeg, mpegversion=(int){2, 4}</literal>
275 * <literal>video/mpeg, mpegversion=(int)2</literal> vs.
276 * <literal>video/mpeg, systemstream=(boolean){ true, false}, mpegversion=(int)[1, 2]</literal>
283 * <emphasis>4. Exit codes the installer should return</emphasis>
286 * The installer should return one of the following exit codes when it exits:
289 * 0 if all of the requested plugins could be installed
290 * (#GST_INSTALL_PLUGINS_SUCCESS)
293 * 1 if no appropriate installation candidate for any of the requested
294 * plugins could be found. Only return this if nothing has been installed
295 * (#GST_INSTALL_PLUGINS_NOT_FOUND)
298 * 2 if an error occured during the installation. The application will
299 * assume that the user will already have seen an error message by the
300 * installer in this case and will usually not show another one
301 * (#GST_INSTALL_PLUGINS_ERROR)
304 * 3 if some of the requested plugins could be installed, but not all
305 * (#GST_INSTALL_PLUGINS_PARTIAL_SUCCESS)
308 * 4 if the user aborted the installation (#GST_INSTALL_PLUGINS_USER_ABORT)
313 * <emphasis>5. How to map the required detail string to packages</emphasis>
316 * It is up to the vendor to find mechanism to map required components from
317 * the detail string to the actual packages/plugins to install. This could
318 * be a hardcoded list of mappings, for example, or be part of the packaging
322 * GStreamer plugin files can be introspected for this information. The
323 * <literal>gst-inspect</literal> utility has a special command line option
324 * that will output information similar to what is required. For example
326 * $ gst-inspect-0.10 --print-plugin-auto-install-info /path/to/libgstvorbis.so
328 * should output something along the lines of
330 * decoder-audio/x-vorbis
333 * element-vorbisparse
335 * encoder-audio/x-vorbis
337 * Note that in the encoder and decoder case the introspected caps can be more
338 * complex with additional fields, e.g.
339 * <literal>audio/mpeg,mpegversion=(int){2,4}</literal>, so they will not
340 * always exactly match the caps wanted by the application. It is up to the
341 * installer to deal with this (either by doing proper caps intersection using
342 * the GStreamer #GstCaps API, or by only taking into account the media type).
345 * Another potential source of problems are plugins such as ladspa or
346 * libvisual where the list of elements depends on the installed
347 * ladspa/libvisual plugins at the time. This is also up to the distribution
348 * to handle (but usually not relevant for playback applications).
357 #include "install-plugins.h"
359 #include <gst/gstinfo.h>
361 #ifdef HAVE_SYS_TYPES_H
362 #include <sys/types.h>
365 #ifdef HAVE_SYS_WAIT_H
366 #include <sys/wait.h>
369 /* best effort to make things compile and possibly even work on win32 */
371 # define WEXITSTATUS(status) ((((guint)(status)) & 0xff00) >> 8)
374 # define WIFEXITED(status) ((((guint)(status)) & 0x7f) == 0)
377 static gboolean install_in_progress; /* FALSE */
380 struct _GstInstallPluginsContext
386 * gst_install_plugins_context_set_xid:
387 * @ctx: a #GstInstallPluginsContext
388 * @xid: the XWindow ID (XID) of the top-level application
390 * This function is for X11-based applications (such as most Gtk/Qt
391 * applications on linux/unix) only. You can use it to tell the external
392 * the XID of your main application window, so the installer can make its
393 * own window transient to your application windonw during the installation.
395 * If set, the XID will be passed to the installer via a --transient-for=XID
396 * command line option.
398 * Gtk+/Gnome application should be able to obtain the XID of the top-level
401 * ##include <gtk/gtk.h>
402 * ##ifdef GDK_WINDOWING_X11
403 * ##include <gdk/gdkx.h>
406 * ##ifdef GDK_WINDOWING_X11
407 * xid = GDK_WINDOW_XWINDOW (GTK_WIDGET (application_window)->window);
415 gst_install_plugins_context_set_xid (GstInstallPluginsContext * ctx, guint xid)
417 g_return_if_fail (ctx != NULL);
423 * gst_install_plugins_context_new:
425 * Creates a new #GstInstallPluginsContext.
427 * Returns: a new #GstInstallPluginsContext. Free with
428 * gst_install_plugins_context_free() when no longer needed
432 GstInstallPluginsContext *
433 gst_install_plugins_context_new (void)
435 return g_new0 (GstInstallPluginsContext, 1);
439 * gst_install_plugins_context_free:
440 * @ctx: a #GstInstallPluginsContext
442 * Frees a #GstInstallPluginsContext.
447 gst_install_plugins_context_free (GstInstallPluginsContext * ctx)
449 g_return_if_fail (ctx != NULL);
455 gst_install_plugins_get_helper (void)
459 helper = g_getenv ("GST_INSTALL_PLUGINS_HELPER");
461 helper = GST_INSTALL_PLUGINS_HELPER;
463 GST_LOG ("Using plugin install helper '%s'", helper);
468 gst_install_plugins_spawn_child (gchar ** details,
469 GstInstallPluginsContext * ctx, GPid * child_pid, gint * exit_status)
474 gchar **argv, xid_str[64] = { 0, };
476 arr = g_ptr_array_new ();
478 /* argv[0] = helper path */
479 g_ptr_array_add (arr, (gchar *) gst_install_plugins_get_helper ());
481 /* add any additional command line args from the context */
482 if (ctx != NULL && ctx->xid != 0) {
483 g_snprintf (xid_str, sizeof (xid_str), "--transient-for=%u", ctx->xid);
484 g_ptr_array_add (arr, xid_str);
487 /* finally, add the detail strings */
488 while (details != NULL && details[0] != NULL) {
489 g_ptr_array_add (arr, details[0]);
493 /* and NULL-terminate */
494 g_ptr_array_add (arr, NULL);
496 argv = (gchar **) arr->pdata;
498 if (child_pid == NULL && exit_status != NULL) {
499 install_in_progress = TRUE;
500 ret = g_spawn_sync (NULL, argv, NULL, (GSpawnFlags) 0, NULL, NULL,
501 NULL, NULL, exit_status, &err);
502 install_in_progress = FALSE;
503 } else if (child_pid != NULL && exit_status == NULL) {
504 install_in_progress = TRUE;
505 ret = g_spawn_async (NULL, argv, NULL, G_SPAWN_DO_NOT_REAP_CHILD, NULL,
506 NULL, child_pid, &err);
508 g_assert_not_reached ();
512 GST_ERROR ("Error spawning plugin install helper: %s", err->message);
516 g_ptr_array_free (arr, TRUE);
520 static GstInstallPluginsReturn
521 gst_install_plugins_return_from_status (gint status)
523 GstInstallPluginsReturn ret;
525 /* did we exit cleanly? */
526 if (!WIFEXITED (status)) {
527 ret = GST_INSTALL_PLUGINS_CRASHED;
529 ret = (GstInstallPluginsReturn) WEXITSTATUS (status);
531 /* did the helper return an invalid status code? */
532 if ((ret < 0 || ret >= GST_INSTALL_PLUGINS_STARTED_OK) &&
533 ret != GST_INSTALL_PLUGINS_INTERNAL_FAILURE) {
534 ret = GST_INSTALL_PLUGINS_INVALID;
538 GST_LOG ("plugin installer exited with status 0x%04x = %s", status,
539 gst_install_plugins_return_get_name (ret));
546 GstInstallPluginsResultFunc func;
548 } GstInstallPluginsAsyncHelper;
551 gst_install_plugins_installer_exited (GPid pid, gint status, gpointer data)
553 GstInstallPluginsAsyncHelper *helper;
554 GstInstallPluginsReturn ret;
556 install_in_progress = FALSE;
558 helper = (GstInstallPluginsAsyncHelper *) data;
559 ret = gst_install_plugins_return_from_status (status);
561 GST_LOG ("calling plugin install result function %p", helper->func);
562 helper->func (ret, helper->user_data);
568 * gst_install_plugins_async:
569 * @details: NULL-terminated array of installer string details (see below)
570 * @ctx: a #GstInstallPluginsContext, or NULL
571 * @func: the function to call when the installer program returns
572 * @user_data: the user data to pass to @func when called, or NULL
574 * Requests plugin installation without blocking. Once the plugins have been
575 * installed or installation has failed, @func will be called with the result
576 * of the installation and your provided @user_data pointer.
578 * This function requires a running GLib/Gtk main loop. If you are not
579 * running a GLib/Gtk main loop, make sure to regularly call
580 * g_main_context_iteration(NULL,FALSE).
582 * The installer strings that make up @detail are typically obtained by
583 * calling gst_missing_plugin_message_get_installer_detail() on missing-plugin
584 * messages that have been caught on a pipeline's bus or created by the
585 * application via the provided API, such as gst_missing_element_message_new().
587 * Returns: result code whether an external installer could be started
592 GstInstallPluginsReturn
593 gst_install_plugins_async (gchar ** details, GstInstallPluginsContext * ctx,
594 GstInstallPluginsResultFunc func, gpointer user_data)
596 GstInstallPluginsAsyncHelper *helper;
599 g_return_val_if_fail (details != NULL, GST_INSTALL_PLUGINS_INTERNAL_FAILURE);
600 g_return_val_if_fail (func != NULL, GST_INSTALL_PLUGINS_INTERNAL_FAILURE);
602 if (install_in_progress)
603 return GST_INSTALL_PLUGINS_INSTALL_IN_PROGRESS;
605 /* if we can't access our helper, don't bother */
606 if (!g_file_test (gst_install_plugins_get_helper (),
607 G_FILE_TEST_IS_EXECUTABLE))
608 return GST_INSTALL_PLUGINS_HELPER_MISSING;
610 if (!gst_install_plugins_spawn_child (details, ctx, &pid, NULL))
611 return GST_INSTALL_PLUGINS_INTERNAL_FAILURE;
613 helper = g_new (GstInstallPluginsAsyncHelper, 1);
615 helper->user_data = user_data;
617 g_child_watch_add (pid, gst_install_plugins_installer_exited, helper);
619 return GST_INSTALL_PLUGINS_STARTED_OK;
623 * gst_install_plugins_sync:
624 * @details: NULL-terminated array of installer string details
625 * @ctx: a #GstInstallPluginsContext, or NULL
627 * Requests plugin installation and block until the plugins have been
628 * installed or installation has failed.
630 * This function should almost never be used, it only exists for cases where
631 * a non-GLib main loop is running and the user wants to run it in a separate
632 * thread and marshal the result back asynchronously into the main thread
633 * using the other non-GLib main loop. You should almost always use
634 * gst_install_plugins_async() instead of this function.
636 * Returns: the result of the installation.
640 GstInstallPluginsReturn
641 gst_install_plugins_sync (gchar ** details, GstInstallPluginsContext * ctx)
645 g_return_val_if_fail (details != NULL, GST_INSTALL_PLUGINS_INTERNAL_FAILURE);
647 if (install_in_progress)
648 return GST_INSTALL_PLUGINS_INSTALL_IN_PROGRESS;
650 /* if we can't access our helper, don't bother */
651 if (!g_file_test (gst_install_plugins_get_helper (),
652 G_FILE_TEST_IS_EXECUTABLE))
653 return GST_INSTALL_PLUGINS_HELPER_MISSING;
655 if (!gst_install_plugins_spawn_child (details, ctx, NULL, &status))
656 return GST_INSTALL_PLUGINS_INTERNAL_FAILURE;
658 return gst_install_plugins_return_from_status (status);
662 * gst_install_plugins_return_get_name:
663 * @ret: the return status code
665 * Convenience function to return the descriptive string associated
666 * with a status code. This function returns English strings and
667 * should not be used for user messages. It is here only to assist
670 * Returns: a descriptive string for the status code in @ret
675 gst_install_plugins_return_get_name (GstInstallPluginsReturn ret)
678 case GST_INSTALL_PLUGINS_SUCCESS:
680 case GST_INSTALL_PLUGINS_NOT_FOUND:
682 case GST_INSTALL_PLUGINS_ERROR:
683 return "install-error";
684 case GST_INSTALL_PLUGINS_CRASHED:
685 return "installer-exit-unclean";
686 case GST_INSTALL_PLUGINS_PARTIAL_SUCCESS:
687 return "partial-success";
688 case GST_INSTALL_PLUGINS_USER_ABORT:
690 case GST_INSTALL_PLUGINS_STARTED_OK:
692 case GST_INSTALL_PLUGINS_INTERNAL_FAILURE:
693 return "internal-failure";
694 case GST_INSTALL_PLUGINS_HELPER_MISSING:
695 return "helper-missing";
696 case GST_INSTALL_PLUGINS_INSTALL_IN_PROGRESS:
697 return "install-in-progress";
698 case GST_INSTALL_PLUGINS_INVALID:
707 * gst_install_plugins_installation_in_progress:
709 * Checks whether plugin installation (initiated by this application only)
710 * is currently in progress.
712 * Returns: TRUE if plugin installation is in progress, otherwise FALSE
717 gst_install_plugins_installation_in_progress (void)
719 return install_in_progress;