module-devd-detect: new module for soundcard hotplug on FreeBSD

Used in addition to module-detect, since devd only provides hotplug events.

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/277>

meson.build

@@ -187,6 +187,8 @@ elif host_machine.system() == 'windows'
   pcreposix_dep = meson.get_compiler('c').find_library('pcreposix')
   platform_socket_dep = [ws2_32_dep, winsock_dep]
   platform_dep = [ole32_dep, ssp_dep, pcreposix_dep]
+elif host_machine.system() == 'freebsd'
+  cdata.set('OS_IS_FREEBSD', 1)
 #elif host_machine.system() == 'solaris'
 #  # Apparently meson has no solaris support?
 #  # Needed to get declarations for msg_control and msg_controllen on Solaris

src/daemon/default.pa.in

@@ -67,6 +67,12 @@ load-module module-coreaudio-detect
 ### Use the static hardware detection module (for systems that lack udev support)
 load-module module-detect
 .endif
+ifelse(@OS_IS_FREEBSD@, 1, [dnl
+### FreeBSD devd is used in addition to static detection (only handles hotplug)
+.ifexists module-devd-detect@PA_SOEXT@
+load-module module-devd-detect
+.endif
+])dnl
 
 ### Automatically connect sink and source if JACK server is present
 .ifexists module-jackdbus-detect@PA_SOEXT@

src/daemon/system.pa.in

@@ -39,6 +39,12 @@ load-module module-coreaudio-detect
 ### Use the static hardware detection module (for systems that lack udev/hal support)
 load-module module-detect
 .endif
+ifelse(@OS_IS_FREEBSD@, 1, [dnl
+### FreeBSD devd is used in addition to static detection (only handles hotplug)
+.ifexists module-devd-detect@PA_SOEXT@
+load-module module-devd-detect
+.endif
+])dnl
 
 ### Load several protocols
 .ifexists module-esound-protocol-unix@PA_SOEXT@

src/modules/meson.build

@@ -217,6 +217,10 @@ if udev_dep.found()
   endif
 endif
 
+if host_machine.system() == 'freebsd'
+  all_modules += [ [ 'module-devd-detect', 'module-devd-detect.c', [], [], [] ] ]
+endif
+
 if x11_dep.found()
   all_modules += [
     [ 'module-x11-bell', 'x11/module-x11-bell.c', [], [], [x11_dep] ],

src/modules/module-devd-detect.c

@@ -0,0 +1,135 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2020 Greg V
+
+  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, see <http://www.gnu.org/licenses/>.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <pulsecore/core-util.h>
+#include <pulsecore/module.h>
+#include <pulsecore/hashmap.h>
+#include <pulsecore/iochannel.h>
+#include <pulsecore/ioline.h>
+#include <pulsecore/log.h>
+
+PA_MODULE_AUTHOR("Greg V");
+PA_MODULE_DESCRIPTION("Detect hotplugged audio hardware and load matching drivers");
+PA_MODULE_VERSION(PACKAGE_VERSION);
+PA_MODULE_LOAD_ONCE(true);
+PA_MODULE_USAGE("");
+
+struct userdata {
+    pa_core *core;
+    pa_hashmap *devices;
+    pa_iochannel *io;
+    pa_ioline *line;
+};
+
+static void line_callback(pa_ioline *line, const char *s, void *userdata) {
+    struct userdata *u = userdata;
+    pa_module *m = NULL;
+    unsigned devnum;
+    uint32_t modidx;
+    char args[64];
+
+    pa_assert(line);
+    pa_assert(u);
+
+    if (sscanf(s, "+pcm%u", &devnum) == 1) {
+        pa_snprintf(args, sizeof(args), "device=/dev/dsp%u", devnum);
+        pa_module_load(&m, u->core, "module-oss", args);
+
+        if (m) {
+            pa_hashmap_put(u->devices, (void *)(uintptr_t)devnum, (void *)(uintptr_t)m->index);
+            pa_log_info("Card %u module loaded (%u).", devnum, m->index);
+        } else {
+            pa_log_info("Card %u failed to load module.", devnum);
+        }
+    } else if (sscanf(s, "-pcm%u", &devnum) == 1) {
+        if (!(modidx = (uint32_t)pa_hashmap_remove(u->devices, (void *)(uintptr_t)devnum)))
+            return;
+
+        pa_log_info("Card %u (module %u) removed.", devnum, modidx);
+
+        if (modidx != PA_INVALID_INDEX)
+            pa_module_unload_request_by_index(u->core, modidx, true);
+    }
+}
+
+static void device_free(void *a) {
+}
+
+int pa__init(pa_module *m) {
+    struct userdata *u = NULL;
+    struct sockaddr_un addr = { .sun_family = AF_UNIX };
+    int fd;
+
+    pa_assert(m);
+
+    m->userdata = u = pa_xnew0(struct userdata, 1);
+    u->core = m->core;
+    u->devices = pa_hashmap_new_full(pa_idxset_trivial_hash_func, pa_idxset_trivial_compare_func, NULL, (pa_free_cb_t) device_free);
+
+    if ((fd = socket(AF_UNIX, SOCK_SEQPACKET, 0)) < 0) {
+        pa_log("Failed to open socket for devd.");
+        return -1;
+    }
+
+    strncpy(addr.sun_path, "/var/run/devd.seqpacket.pipe", sizeof(addr.sun_path) - 1);
+
+    if (connect(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        pa_log("Failed to connect to devd.");
+        close(fd);
+        return -1;
+    }
+
+    pa_assert_se(u->io = pa_iochannel_new(m->core->mainloop, fd, -1));
+    pa_assert_se(u->line = pa_ioline_new(u->io));
+    pa_ioline_set_callback(u->line, line_callback, m->userdata);
+
+    return 0;
+}
+
+void pa__done(pa_module *m) {
+    struct userdata *u;
+
+    pa_assert(m);
+
+    if (!(u = m->userdata))
+        return;
+
+    if (u->devices)
+        pa_hashmap_free(u->devices);
+
+    if (u->line)
+        pa_ioline_close(u->line);
+
+    if (u->io)
+        pa_iochannel_free(u->io);
+
+    pa_xfree(u);
+}