fixup! WIP: rtkit support

.gitignore

@@ -1,3 +1,5 @@
 /output/
 
 __pycache__/
+
+result

meson_options.txt

@@ -192,6 +192,7 @@ option('solaris_output', type: 'feature', description: 'Solaris /dev/audio suppo
 #
 
 option('dbus', type: 'feature', description: 'D-Bus support')
+option('rtkit', type: 'feature', description: 'Use RealtimeKit for requesting realtime scheduling')
 option('expat', type: 'feature', description: 'Expat XML support')
 option('icu', type: 'feature', description: 'Use libicu for Unicode')
 option('iconv', type: 'feature', description: 'Use iconv() for character set conversion')

shell.nix

@@ -0,0 +1,80 @@
+{ pkgs ? import <nixpkgs> { } }:
+pkgs.mkShell {
+  nativeBuildInputs = with pkgs; [
+    meson
+    ninja
+    pkg-config
+
+    # For documentation
+    doxygen
+    python3Packages.sphinx
+    python3Packages.sphinx-rtd-theme
+  ];
+
+  buildInputs = with pkgs; [
+    glib
+    systemd
+    boost
+    fmt
+
+    # Inputs
+    curl
+    libmms
+    libnfs
+    liburing
+    samba
+
+    # Archive support
+    bzip2
+    zziplib
+
+    # Codecs
+    audiofile
+    faad2
+    ffmpeg
+    flac
+    fluidsynth
+    game-music-emu
+    libmad
+    libmikmod
+    mpg123
+    libopus
+    libvorbis
+    lame
+
+    # Filters
+    libsamplerate
+    soxr
+
+    # Outputs
+    alsa-lib
+    libjack2
+    libpulseaudio
+    libshout
+    pipewire
+
+    # Misc
+    icu
+    sqlite
+    avahi
+    dbus
+    pcre2
+    libgcrypt
+    expat
+
+    # Services
+    # yajl # This is broken, maybe because of the fork used in nixpkgs?
+
+    # Client support
+    libmpdclient
+
+    # Tag support
+    libid3tag
+
+    # For tests
+    gtest
+    zip
+  ];
+
+  hardeningDisable = [ "fortify" ];
+}

src/event/Thread.cxx

@@ -8,6 +8,7 @@
 #include "lib/fmt/ExceptionFormatter.hxx"
 #include "util/Domain.hxx"
 #include "Log.hxx"
+#include <boost/stacktrace.hpp>
 
 #ifdef HAVE_URING
 #include "util/ScopeExit.hxx"
@@ -54,7 +55,8 @@ EventThread::Run() noexcept
 		} catch (...) {
 			FmtInfo(event_domain,
 				"RTIOThread could not get realtime scheduling, continuing anyway: {}",
-				std::current_exception());
+				/* std::current_exception()); */
+        boost::stacktrace::to_string(boost::stacktrace::stacktrace()));
 		}
 	} else {
 #ifdef HAVE_URING

src/lib/yajl/Callbacks.hxx

@@ -7,7 +7,7 @@
 
 #include <string_view>
 
-#include <yajl_parse.h>
+#include <yajl/yajl_parse.h>
 
 namespace Yajl {
 

src/lib/yajl/Gen.hxx

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include <yajl_gen.h>
+#include <yajl/yajl_gen.h>
 
 #include <algorithm>
 #include <span>

src/lib/yajl/Handle.hxx

@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include <yajl_parse.h>
+#include <yajl/yajl_parse.h>
 
 #include <utility>
 

src/thread/Util.cxx

@@ -8,10 +8,207 @@
 #include <sched.h>
 #include <sys/syscall.h>
 #include <unistd.h>
+#include <dbus/dbus.h>
+#include <string.h>
+#include <sys/types.h>
+#include <errno.h>
+#include "lib/fmt/RuntimeError.hxx"
 #elif defined(_WIN32)
 #include <windows.h>
 #endif
 
+
+#ifdef __linux__
+const char* RTKIT_SERVICE_NAME = "org.freedesktop.RealtimeKit1";
+const char* RTKIT_OBJECT_PATH = "/org/freedesktop/RealtimeKit1";
+
+// static int
+// rtkit_get_max_realtime_priority(DBusConnection &connection)
+// {
+//   // TODO: Implement this function
+//   DBusError error;
+// }
+
+// static void
+// rtkit_make_realtime(DBusConnection &connection, pid_t thread, int priority)
+// {
+//   // TODO: Implement this function
+
+// }
+#endif
+
+// TODO: minimize and drop
+#ifdef __linux__
+
+#define RTKIT_SERVICE_NAME "org.freedesktop.RealtimeKit1"
+#define RTKIT_OBJECT_PATH "/org/freedesktop/RealtimeKit1"
+
+static pid_t _gettid(void) {
+        return (pid_t) syscall(SYS_gettid);
+}
+
+static int translate_error(const char *name) {
+        if (strcmp(name, DBUS_ERROR_NO_MEMORY) == 0)
+                return -ENOMEM;
+        if (strcmp(name, DBUS_ERROR_SERVICE_UNKNOWN) == 0 ||
+            strcmp(name, DBUS_ERROR_NAME_HAS_NO_OWNER) == 0)
+                return -ENOENT;
+        if (strcmp(name, DBUS_ERROR_ACCESS_DENIED) == 0 ||
+            strcmp(name, DBUS_ERROR_AUTH_FAILED) == 0)
+                return -EACCES;
+
+        return -EIO;
+}
+
+static long long rtkit_get_int_property(DBusConnection *connection, const char* propname, long long* propval) {
+        DBusMessage *m = NULL, *r = NULL;
+        DBusMessageIter iter, subiter;
+        dbus_int64_t i64;
+        dbus_int32_t i32;
+        DBusError error;
+        int current_type;
+        long long ret;
+        const char * interfacestr = "org.freedesktop.RealtimeKit1";
+
+        dbus_error_init(&error);
+
+        if (!(m = dbus_message_new_method_call(
+                              RTKIT_SERVICE_NAME,
+                              RTKIT_OBJECT_PATH,
+                              "org.freedesktop.DBus.Properties",
+                              "Get"))) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        if (!dbus_message_append_args(
+                            m,
+                            DBUS_TYPE_STRING, &interfacestr,
+                            DBUS_TYPE_STRING, &propname,
+                            DBUS_TYPE_INVALID)) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(r = dbus_connection_send_with_reply_and_block(connection, m, -1, &error))) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+        if (dbus_set_error_from_message(&error, r)) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+        ret = -EBADMSG;
+        dbus_message_iter_init(r, &iter);
+        while ((current_type = dbus_message_iter_get_arg_type (&iter)) != DBUS_TYPE_INVALID) {
+
+                if (current_type == DBUS_TYPE_VARIANT) {
+                        dbus_message_iter_recurse(&iter, &subiter);
+
+                        while ((current_type = dbus_message_iter_get_arg_type (&subiter)) != DBUS_TYPE_INVALID) {
+
+                                if (current_type == DBUS_TYPE_INT32) {
+                                        dbus_message_iter_get_basic(&subiter, &i32);
+                                        *propval = i32;
+                                        ret = 0;
+                                }
+
+                                if (current_type == DBUS_TYPE_INT64) {
+                                        dbus_message_iter_get_basic(&subiter, &i64);
+                                        *propval = i64;
+                                        ret = 0;
+                                }
+
+                                dbus_message_iter_next (&subiter);
+                        }
+                }
+                dbus_message_iter_next (&iter);
+        }
+
+finish:
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (r)
+                dbus_message_unref(r);
+
+        dbus_error_free(&error);
+
+        return ret;
+}
+
+static int rtkit_get_max_realtime_priority(DBusConnection *connection) {
+        long long retval;
+        int err;
+
+        err = rtkit_get_int_property(connection, "MaxRealtimePriority", &retval);
+        return err < 0 ? err : retval;
+}
+
+static int rtkit_make_realtime(DBusConnection *connection, pid_t thread, int priority) {
+        DBusMessage *m = NULL, *r = NULL;
+        dbus_uint64_t u64;
+        dbus_uint32_t u32;
+        DBusError error;
+        int ret;
+
+        dbus_error_init(&error);
+
+        if (thread == 0)
+                thread = _gettid();
+
+        if (!(m = dbus_message_new_method_call(
+                              RTKIT_SERVICE_NAME,
+                              RTKIT_OBJECT_PATH,
+                              "org.freedesktop.RealtimeKit1",
+                              "MakeThreadRealtime"))) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        u64 = (dbus_uint64_t) thread;
+        u32 = (dbus_uint32_t) priority;
+
+        if (!dbus_message_append_args(
+                            m,
+                            DBUS_TYPE_UINT64, &u64,
+                            DBUS_TYPE_UINT32, &u32,
+                            DBUS_TYPE_INVALID)) {
+                ret = -ENOMEM;
+                goto finish;
+        }
+
+        if (!(r = dbus_connection_send_with_reply_and_block(connection, m, -1, &error))) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+
+        if (dbus_set_error_from_message(&error, r)) {
+                ret = translate_error(error.name);
+                goto finish;
+        }
+
+        ret = 0;
+
+finish:
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (r)
+                dbus_message_unref(r);
+
+        dbus_error_free(&error);
+
+        return ret;
+}
+
+#endif
+
 #ifdef __linux__
 
 #ifndef ANDROID
@@ -75,14 +272,50 @@ SetThreadRealtime()
 {
 #ifdef __linux__
 	struct sched_param sched_param;
-	sched_param.sched_priority = 40;
+	sched_param.sched_priority = 20;
 
 	int policy = SCHED_FIFO;
 #ifdef SCHED_RESET_ON_FORK
 	policy |= SCHED_RESET_ON_FORK;
 #endif
 
-	if (linux_sched_setscheduler(0, policy, &sched_param) < 0)
-		throw MakeErrno("sched_setscheduler failed");
+	int res = linux_sched_setscheduler(0, policy, &sched_param);
+
+	if (res < 0 && errno == EPERM) {
+		DBusError error;
+		DBusConnection *system_bus;
+
+		dbus_error_init(&error);
+
+		system_bus = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
+		if (dbus_error_is_set(&error)) {
+			throw FmtRuntimeError("could not connect to dbus: %s", error.message);
+		}
+		dbus_error_free(&error);
+
+		int max_realtime_priority;
+		if ((max_realtime_priority = rtkit_get_max_realtime_priority(system_bus)) < 0) {
+			dbus_connection_unref(system_bus);
+			throw MakeErrno("could not retrieve maximum realtime priority allowed");
+		}
+
+		if (max_realtime_priority < sched_param.sched_priority) {
+			sched_param.sched_priority = max_realtime_priority;
+			/* dbus_connection_unref(system_bus); */
+			/* throw MakeErrno("maximum realtime priority is below 40"); */
+		}
+
+		if (rtkit_make_realtime(system_bus, 0, sched_param.sched_priority) < 0) {
+			dbus_connection_unref(system_bus);
+			throw MakeErrno("failed to request realtime scheduling");
+		}
+
+		dbus_connection_unref(system_bus);
+		res = 0;
+	}
+
+	// if (res < 0) {
+	// 	throw MakeErrno("sched_setscheduler failed");
+	// }
 #endif	// __linux__
 }

src/thread/meson.build

@@ -7,6 +7,13 @@ else
   threads_dep = dependency('threads')
 endif
 
+if is_linux
+  dbus_dep = dependency('dbus-1', required: get_option('dbus'))
+  conf.set('ENABLE_DBUS', dbus_dep.found())
+else
+  dbus_dep = []
+endif
+
 conf.set('HAVE_PTHREAD_SETNAME_NP', compiler.has_function('pthread_setname_np', dependencies: threads_dep))
 
 thread = static_library(
@@ -16,6 +23,7 @@ thread = static_library(
   include_directories: inc,
   dependencies: [
     threads_dep,
+    dbus_dep,
   ],
 )