udev: add module-udev-detect for discovering and configuring devices

src/modules/module-udev-detect.c

@@ -0,0 +1,348 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Lennart Poettering
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  PulseAudio 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 Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+#include <sys/inotify.h>
+#include <libudev.h>
+
+#include <pulsecore/modargs.h>
+#include <pulsecore/core-error.h>
+#include <pulsecore/core-util.h>
+#include <pulsecore/namereg.h>
+
+#include "module-udev-detect-symdef.h"
+
+PA_MODULE_AUTHOR("Lennart Poettering");
+PA_MODULE_DESCRIPTION("Detect available audio hardware and load matching drivers");
+PA_MODULE_VERSION(PACKAGE_VERSION);
+PA_MODULE_LOAD_ONCE(TRUE);
+
+struct device {
+    char *path;
+    char *card_name;
+    uint32_t module;
+};
+
+struct userdata {
+    pa_core *core;
+    pa_hashmap *devices;
+    pa_bool_t use_tsched;
+    struct udev* udev;
+    struct udev_monitor *monitor;
+    pa_io_event *io;
+};
+
+static const char* const valid_modargs[] = {
+    "tsched",
+    NULL
+};
+
+static void device_free(struct device *d) {
+    pa_assert(d);
+
+    pa_xfree(d->path);
+    pa_xfree(d->card_name);
+    pa_xfree(d);
+}
+
+static const char *path_get_card_id(const char *path) {
+    const char *e;
+
+    if (!path)
+        return NULL;
+
+    if (!(e = strrchr(path, '/')))
+        return NULL;
+
+    if (!pa_startswith(e, "/card"))
+        return NULL;
+
+    return e + 5;
+}
+
+static void verify_access(struct userdata *u, struct device *d) {
+    char *cd;
+    int r;
+    pa_card *card;
+
+    pa_assert(u);
+    pa_assert(d);
+
+    cd = pa_sprintf_malloc("%s/controlC%s", d->path, path_get_card_id(d->path));
+    r = access(cd, W_OK);
+    pa_log_info("%s is accessible: %s", cd, pa_yes_no(r >= 0));
+    pa_xfree(cd);
+
+    if ((card = pa_namereg_get(u->core, d->card_name, PA_NAMEREG_CARD)))
+        pa_card_suspend(card, r < 0, PA_SUSPEND_SESSION);
+}
+
+static void card_changed(struct userdata *u, struct udev_device *dev) {
+    struct device *d;
+    const char *path;
+    const char *t;
+    char *card_name, *args;
+    pa_module *m;
+    char *n;
+
+    pa_assert(u);
+    pa_assert(dev);
+
+    path = udev_device_get_devpath(dev);
+
+    if ((d = pa_hashmap_get(u->devices, path))) {
+        verify_access(u, d);
+        return;
+    }
+
+    if (!(t = udev_device_get_property_value(dev, "PULSE_NAME")))
+        if (!(t = udev_device_get_property_value(dev, "ID_ID")))
+            if (!(t = udev_device_get_property_value(dev, "ID_PATH")))
+                t = path_get_card_id(path);
+
+    n = pa_namereg_make_valid_name(t);
+
+    card_name = pa_sprintf_malloc("alsa_card.%s", n);
+    args = pa_sprintf_malloc("device_id=\"%s\" "
+                             "name=\"%s\" "
+                             "card_name=\"%s\" "
+                             "tsched=%i "
+                             "card_properties=\"module-udev-detect.discovered=1\"",
+                             path_get_card_id(path),
+                             n,
+                             card_name,
+                             (int) u->use_tsched);
+
+    pa_log_debug("Loading module-alsa-card with arguments '%s'", args);
+    m = pa_module_load(u->core, "module-alsa-card", args);
+    pa_xfree(args);
+
+    if (m) {
+        pa_log_info("Card %s (%s) added.", path, n);
+
+        d = pa_xnew(struct device, 1);
+        d->path = pa_xstrdup(path);
+        d->card_name = card_name;
+        d->module = m->index;
+
+        pa_hashmap_put(u->devices, d->path, d);
+    } else
+        pa_xfree(card_name);
+
+    pa_xfree(n);
+}
+
+static void remove_card(struct userdata *u, struct udev_device *dev) {
+    struct device *d;
+
+    pa_assert(u);
+    pa_assert(dev);
+
+    if (!(d = pa_hashmap_remove(u->devices, udev_device_get_devpath(dev))))
+        return;
+
+    pa_log_info("Card %s removed.", d->path);
+    pa_module_unload_request_by_index(u->core, d->module, TRUE);
+    device_free(d);
+}
+
+static void process_device(struct userdata *u, struct udev_device *dev) {
+    const char *action, *ff;
+
+    pa_assert(u);
+    pa_assert(dev);
+
+    if (udev_device_get_property_value(dev, "PULSE_IGNORE")) {
+        pa_log_info("Ignoring %s, because marked so.", udev_device_get_devpath(dev));
+        return;
+    }
+
+    if ((ff = udev_device_get_property_value(dev, "SOUND_FORM_FACTOR")) &&
+        pa_streq(ff, "modem")) {
+        pa_log_info("Ignoring %s, because it is a modem.", udev_device_get_devpath(dev));
+        return;
+    }
+
+    action = udev_device_get_action(dev);
+
+    if (action && pa_streq(action, "remove"))
+        remove_card(u, dev);
+    else if ((!action || pa_streq(action, "change")) &&
+             udev_device_get_property_value(dev, "SOUND_INITIALIZED"))
+        card_changed(u, dev);
+
+    /* For an explanation why we don't look for 'add' events here
+     * have a look into /lib/udev/rules.d/78-sound-card.rules! */
+}
+
+static void process_path(struct userdata *u, const char *path) {
+    struct udev_device *dev;
+
+    if (!path_get_card_id(path))
+        return;
+
+    if (!(dev = udev_device_new_from_syspath(u->udev, path))) {
+        pa_log("Failed to get udev device object from udev.");
+        return;
+    }
+
+    process_device(u, dev);
+    udev_device_unref(dev);
+}
+
+static void monitor_cb(pa_mainloop_api*a, pa_io_event* e, int fd, pa_io_event_flags_t events, void *userdata) {
+    struct userdata *u = userdata;
+    struct udev_device *dev;
+
+    pa_assert(a);
+
+    if (!(dev = udev_monitor_receive_device(u->monitor))) {
+        pa_log("Failed to get udev device object from monitor.");
+        return;
+    }
+
+    if (!path_get_card_id(udev_device_get_devpath(dev)))
+        return;
+
+    process_device(u, dev);
+    udev_device_unref(dev);
+}
+
+int pa__init(pa_module *m) {
+    struct userdata *u = NULL;
+    pa_modargs *ma;
+    struct udev_enumerate *enumerate = NULL;
+    struct udev_list_entry *item = NULL, *first = NULL;
+    int fd;
+
+    pa_assert(m);
+
+    if (!(ma = pa_modargs_new(m->argument, valid_modargs))) {
+        pa_log("Failed to parse module arguments");
+        goto fail;
+    }
+
+    m->userdata = u = pa_xnew(struct userdata, 1);
+    u->core = m->core;
+    u->devices = pa_hashmap_new(pa_idxset_string_hash_func, pa_idxset_string_compare_func);
+    u->use_tsched = TRUE;
+
+    if (pa_modargs_get_value_boolean(ma, "tsched", &u->use_tsched) < 0) {
+        pa_log("Failed to parse tsched argument.");
+        goto fail;
+    }
+
+    if (!(u->udev = udev_new())) {
+        pa_log("Failed to initialize udev library.");
+        goto fail;
+    }
+
+    if (!(u->monitor = udev_monitor_new_from_netlink(u->udev, "udev"))) {
+        pa_log("Failed to initialize monitor.");
+        goto fail;
+    }
+
+    errno = 0;
+    if (udev_monitor_enable_receiving(u->monitor) < 0) {
+        pa_log("Failed to enable monitor: %s", pa_cstrerror(errno));
+        if (errno == EPERM)
+            pa_log_info("Most likely your kernel is simply too old and "
+                        "allows only priviliged processes to listen to device events. "
+                        "Please upgrade your kernel to at least 2.6.30.");
+        goto fail;
+    }
+
+    if ((fd = udev_monitor_get_fd(u->monitor)) < 0) {
+        pa_log("Failed to get udev monitor fd.");
+        goto fail;
+    }
+
+    pa_assert_se(u->io = u->core->mainloop->io_new(u->core->mainloop, fd, PA_IO_EVENT_INPUT, monitor_cb, u));
+
+    if (!(enumerate = udev_enumerate_new(u->udev))) {
+        pa_log("Failed to initialize udev enumerator.");
+        goto fail;
+    }
+
+    if (udev_enumerate_add_match_subsystem(enumerate, "sound") < 0) {
+        pa_log("Failed to match to subsystem.");
+        goto fail;
+    }
+
+    if (udev_enumerate_scan_devices(enumerate) < 0) {
+        pa_log("Failed to scan for devices.");
+        goto fail;
+    }
+
+    first = udev_enumerate_get_list_entry(enumerate);
+    udev_list_entry_foreach(item, first)
+        process_path(u, udev_list_entry_get_name(item));
+
+    udev_enumerate_unref(enumerate);
+
+    pa_log_info("Loaded %u modules.", pa_hashmap_size(u->devices));
+
+    pa_modargs_free(ma);
+
+    return 0;
+
+fail:
+
+    if (enumerate)
+        udev_enumerate_unref(enumerate);
+
+    if (ma)
+        pa_modargs_free(ma);
+
+    pa__done(m);
+
+    return -1;
+}
+
+void pa__done(pa_module *m) {
+    struct userdata *u;
+
+    pa_assert(m);
+
+    if (!(u = m->userdata))
+        return;
+
+    if (u->monitor)
+        udev_monitor_unref(u->monitor);
+
+    if (u->udev)
+        udev_unref(u->udev);
+
+    if (u->devices) {
+        struct device *d;
+
+        while ((d = pa_hashmap_steal_first(u->devices)))
+            device_free(d);
+
+        pa_hashmap_free(u->devices, NULL, NULL);
+    }
+
+    pa_xfree(u);
+}