Remove systemd lock-file gating and add automatic shell port selection (#1763)

Copilot · derselbst · web-flow · commit 6ff44b714268 · 2026-03-14T15:53:32.000+01:00
Co-authored-by: copilot-swe-agent[bot] &lt;198982749+Copilot@users.noreply.github.com&gt;
Co-authored-by: derselbst &lt;8152480+derselbst@users.noreply.github.com&gt;
Co-authored-by: derselbst &lt;tom.mbrt@googlemail.com&gt;
diff --git a/.gitignore b/.gitignore
@@ -42,3 +42,5 @@ install_manifest.txt
 *.pro.user*
 *.user
 *.vscode
+_codeql_build_dir/
+_codeql_detected_source_root
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -974,9 +974,6 @@ if ( UNIX )
         configure_file ( fluidsynth.service.in
         ${FluidSynth_BINARY_DIR}/fluidsynth.service @ONLY )
 
-        configure_file ( fluidsynth.tmpfiles.in
-        ${FluidSynth_BINARY_DIR}/fluidsynth.tmpfiles @ONLY )
-
         configure_file ( fluidsynth.conf.in
         ${FluidSynth_BINARY_DIR}/fluidsynth.conf @ONLY )
 
diff --git a/contrib/fluidsynth.spec b/contrib/fluidsynth.spec
@@ -97,7 +97,6 @@ This package contains the shared library for Fluidsynth.
 # manually install systemd files
 install -Dm 644 build/fluidsynth.conf %{buildroot}%{_fillupdir}/sysconfig.%{name}
 install -Dm 644 build/fluidsynth.service %{buildroot}%{_unitdir}/%{name}.service
-install -Dm 644 build/fluidsynth.tmpfiles %{buildroot}%{_tmpfilesdir}/%{name}.conf
 install -d %{buildroot}%{_sbindir}
 ln -s %{_sbindir}/service %{buildroot}%{_sbindir}/rc%{name}
 
@@ -128,7 +127,6 @@ ln -s %{_sbindir}/service %{buildroot}%{_sbindir}/rc%{name}
 %{_unitdir}/%{name}.service
 %{_sbindir}/rc%{name}
 %{_fillupdir}/sysconfig.%{name}
-%{_tmpfilesdir}/%{name}.conf
 %endif
 
 %files devel
diff --git a/doc/fluidsettings.xml b/doc/fluidsettings.xml
@@ -888,11 +888,10 @@ Developers:
         <setting>
             <name>port</name>
             <type>int</type>
-            <def>9800</def>
-            <min>1</min>
+            <def>0</def>
+            <min>0</min>
             <max>65535</max>
-            <desc>The shell can be used in a client/server mode. This setting controls what TCP/IP port the server uses.</desc>
+            <desc>The shell can be used in a client/server mode. This setting controls what TCP/IP port the server uses. Since fluidsynth 2.5.4, a value of 0 enables auto mode and selects the first free port, probing from 9800 upwards. Older versions used 9800 as default port. Note that when set to 0, fluidsynth will update the setting during server creation (new_fluid_server2()) with the actual port number used.</desc>
         </setting>
     </shell>
 </fluidsettings>
-
diff --git a/doc/recent_changes.txt b/doc/recent_changes.txt
@@ -1,6 +1,9 @@
 /*!
 
 \page RecentChanges Recent Changes
+\section NewIn2_5_4 What's new in 2.5.4?
+- By default, fluidsynth now auto selects the TCP port for the shell server, see \setting{shell_port}
+
 \section NewIn2_5_0 What's new in 2.5.0?
 - #FLUID_MOD_SIN is now deprecated, use the newly added fluid_mod_set_custom_mapping()
 - A new mode for the custom IIR filter has been added: #FLUID_IIR_BEANLAND
diff --git a/fluidsynth.service.in b/fluidsynth.service.in
@@ -4,8 +4,6 @@ Documentation=man:fluidsynth(1)
 After=sound.target
 After=pipewire.service pulseaudio.service
 Wants=pipewire.service pulseaudio.service
-# If you need more than one instance, use `systemctl edit` to override this:
-ConditionPathExists=!/run/lock/fluidsynth/fluidsynth.lock
 ConditionUser=!@system
 
 [Service]
@@ -27,9 +25,6 @@ Environment=OTHER_OPTS= SOUND_FONT=
 EnvironmentFile=@FLUID_DAEMON_ENV_FILE@
 EnvironmentFile=-%h/.config/fluidsynth
 ExecStart=@CMAKE_INSTALL_FULL_BINDIR@/fluidsynth -is $OTHER_OPTS "${SOUND_FONT}"
-ExecStartPre=touch /run/lock/fluidsynth/fluidsynth.lock
-ExecStopPost=rm -f /run/lock/fluidsynth/fluidsynth.lock
 
 [Install]
 WantedBy=default.target
-
diff --git a/fluidsynth.tmpfiles.in b/fluidsynth.tmpfiles.in
diff --git a/include/fluidsynth/shell.h b/include/fluidsynth/shell.h
@@ -114,9 +114,10 @@ FLUIDSYNTH_API void delete_fluid_shell(fluid_shell_t *shell);
  *
  * TCP socket server for a command handler.
  *
- * The socket server will open the TCP port set by \ref settings_shell_port 
- * (default 9800) and starts a new thread and \ref command_handler for each 
- * incoming connection.
+ * The socket server will open the TCP port set by \ref settings_shell_port
+ * (default 9800). If the setting is 0, the first free port is selected
+ * automatically, probing from 9800 upwards. The server starts a new thread and
+ * \ref command_handler for each incoming connection.
  *
  * @note The server is only available if libfluidsynth has been compiled
  * with network support (enable-network). Without network support, all related
diff --git a/src/bindings/fluid_cmd.c b/src/bindings/fluid_cmd.c
@@ -67,7 +67,7 @@ static int fluid_handle_voice_count(void *data, int ac, char **av,
 void fluid_shell_settings(fluid_settings_t *settings)
 {
     fluid_settings_register_str(settings, "shell.prompt", "", 0);
-    fluid_settings_register_int(settings, "shell.port", 9800, 1, 65535, 0);
+    fluid_settings_register_int(settings, "shell.port", 0, 0, 65535, 0);
 }
 
 
@@ -4482,6 +4482,17 @@ new_fluid_server2(fluid_settings_t *settings,
         return NULL;
     }
 
+    if(port == 0)
+    {
+        int selected_port = fluid_server_socket_get_port(server->socket);
+
+        if(selected_port != FLUID_FAILED)
+        {
+            fluid_settings_setint(settings, "shell.port", selected_port);
+            FLUID_LOG(FLUID_INFO, "shell.port=0, using automatically selected port %d", selected_port);
+        }
+    }
+
     return server;
 #else
     FLUID_LOG(FLUID_WARN, "Network support disabled on this platform.");
diff --git a/src/utils/fluid_sys.c b/src/utils/fluid_sys.c
@@ -70,6 +70,7 @@ struct _fluid_timer_t
 struct _fluid_server_socket_t
 {
     fluid_socket_t socket;
+    int port;
     fluid_thread_t *thread;
     int cont;
     fluid_server_func_t func;
@@ -1333,6 +1334,12 @@ int fluid_server_socket_join(fluid_server_socket_t *server_socket)
     return fluid_thread_join(server_socket->thread);
 }
 
+int fluid_server_socket_get_port(fluid_server_socket_t *server_socket)
+{
+    fluid_return_val_if_fail(server_socket != NULL, FLUID_FAILED);
+    return server_socket->port;
+}
+
 static int fluid_socket_init(void)
 {
 #ifdef _WIN32
@@ -1380,10 +1387,13 @@ void fluid_socket_close(fluid_socket_t sock)
 {
     if(sock != INVALID_SOCKET)
     {
+        /* Trigger any pending blocking I/O (e.g. accept()) before closing. */
 #ifdef _WIN32
+        shutdown(sock, SD_BOTH);
         closesocket(sock);
 
 #else
+        shutdown(sock, SHUT_RDWR);
         close(sock);
 #endif
     }
@@ -1469,6 +1479,9 @@ new_fluid_server_socket(int port, fluid_server_func_t func, void *data)
     const struct sockaddr *addr;
     size_t addr_size;
     fluid_socket_t sock;
+    int current_port = port;
+    int auto_port = (port == 0);
+    int bind_error;
 
     fluid_return_val_if_fail(func != NULL, NULL);
 
@@ -1479,16 +1492,19 @@ new_fluid_server_socket(int port, fluid_server_func_t func, void *data)
 
     FLUID_MEMSET(&addr4, 0, sizeof(addr4));
     addr4.sin_family = AF_INET;
-    addr4.sin_port = htons((uint16_t)port);
     addr4.sin_addr.s_addr = htonl(INADDR_ANY);
 
 #ifdef IPV6_SUPPORT
     FLUID_MEMSET(&addr6, 0, sizeof(addr6));
     addr6.sin6_family = AF_INET6;
-    addr6.sin6_port = htons((uint16_t)port);
     addr6.sin6_addr = in6addr_any;
 #endif
 
+    if(auto_port)
+    {
+        current_port = FLUID_SHELL_AUTO_PORT_START;
+    }
+
 #ifdef IPV6_SUPPORT
     sock = socket(AF_INET6, SOCK_STREAM, 0);
     addr = (const struct sockaddr *) &addr6;
@@ -1516,12 +1532,49 @@ new_fluid_server_socket(int port, fluid_server_func_t func, void *data)
         return NULL;
     }
     
-    if(bind(sock, addr, (int) addr_size) == SOCKET_ERROR)
+    while(1)
     {
-        FLUID_LOG(FLUID_ERR, "Got error %d while trying to bind server socket", fluid_socket_get_error());
-        fluid_socket_close(sock);
-        fluid_socket_cleanup();
-        return NULL;
+        addr4.sin_port = htons((uint16_t) current_port);
+#ifdef IPV6_SUPPORT
+        addr6.sin6_port = htons((uint16_t) current_port);
+#endif
+        if(bind(sock, addr, (int) addr_size) == 0)
+        {
+            break;
+        }
+
+        bind_error = fluid_socket_get_error();
+
+        if(!auto_port)
+        {
+            FLUID_LOG(FLUID_ERR, "Got error %d while trying to bind server socket", bind_error);
+            fluid_socket_close(sock);
+            fluid_socket_cleanup();
+            return NULL;
+        }
+
+#if defined(_WIN32)
+        if(bind_error != WSAEADDRINUSE)
+#else
+        if(bind_error != EADDRINUSE)
+#endif
+        {
+            FLUID_LOG(FLUID_ERR, "Got error %d while trying to bind server socket", bind_error);
+            fluid_socket_close(sock);
+            fluid_socket_cleanup();
+            return NULL;
+        }
+
+        if(current_port == FLUID_TCP_PORT_MAX)
+        {
+            FLUID_LOG(FLUID_ERR, "No free TCP port available for shell server auto mode (starting at %d)",
+                      FLUID_SHELL_AUTO_PORT_START);
+            fluid_socket_close(sock);
+            fluid_socket_cleanup();
+            return NULL;
+        }
+
+        current_port++;
     }
 
     if(listen(sock, SOMAXCONN) == SOCKET_ERROR)
@@ -1543,6 +1596,7 @@ new_fluid_server_socket(int port, fluid_server_func_t func, void *data)
     }
 
     server_socket->socket = sock;
+    server_socket->port = current_port;
     server_socket->func = func;
     server_socket->data = data;
     server_socket->cont = 1;
diff --git a/src/utils/fluid_sys.h b/src/utils/fluid_sys.h
@@ -285,6 +285,9 @@ int fluid_thread_join(fluid_thread_t *thread);
 
 /* Sockets and I/O */
 
+#define FLUID_SHELL_AUTO_PORT_START             9800
+#define FLUID_TCP_PORT_MAX                      65535
+
 int fluid_istream_readline(fluid_istream_t in, fluid_ostream_t out, char *prompt, char *buf, int len);
 int fluid_ostream_printf(fluid_ostream_t out, const char *format, ...);
 
@@ -302,6 +305,7 @@ typedef int (*fluid_server_func_t)(void *data, fluid_socket_t client_socket, cha
 fluid_server_socket_t *new_fluid_server_socket(int port, fluid_server_func_t func, void *data);
 void delete_fluid_server_socket(fluid_server_socket_t *sock);
 int fluid_server_socket_join(fluid_server_socket_t *sock);
+int fluid_server_socket_get_port(fluid_server_socket_t *sock);
 void fluid_socket_close(fluid_socket_t sock);
 fluid_istream_t fluid_socket_get_istream(fluid_socket_t sock);
 fluid_ostream_t fluid_socket_get_ostream(fluid_socket_t sock);
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
@@ -35,6 +35,7 @@ ADD_FLUID_TEST(test_modulator)
 ADD_FLUID_TEST(test_default_mod)
 ADD_FLUID_TEST(test_ABI)
 ADD_FLUID_TEST(test_file_seek_tell)
+ADD_FLUID_TEST(test_shell_server_auto_port)
 
 if ( GLIB_SUPPORT AND GLib2_VERSION VERSION_GREATER_EQUAL 2.33.12 )
     # Earlier versions of GLib had broken comment handling and should not be compared to
@@ -390,4 +391,3 @@ add_dependencies(check_manual renderGeneralUserDemo)
 add_dependencies(check_manual renderBankSelect)
 add_dependencies(check_manual renderDMOD)
 add_dependencies(check_manual renderRPN)
-
diff --git a/test/test_shell_server_auto_port.c b/test/test_shell_server_auto_port.c
@@ -0,0 +1,60 @@
+#include "test.h"
+#include "fluidsynth.h"
+#include "fluid_sys.h"
+
+void test_server_creation(fluid_settings_t* settings1, fluid_settings_t* settings2)
+{
+    fluid_server_t *server1, *server2;
+    int port1, port2;
+
+    server1 = new_fluid_server2(settings1, NULL, NULL, NULL);
+    TEST_ASSERT(server1 != NULL);
+    TEST_SUCCESS(fluid_settings_getint(settings1, "shell.port", &port1));
+    TEST_ASSERT(port1 >= FLUID_SHELL_AUTO_PORT_START && port1 <= FLUID_TCP_PORT_MAX);
+
+    server2 = new_fluid_server2(settings2, NULL, NULL, NULL);
+    TEST_ASSERT(server2 != NULL);
+    TEST_SUCCESS(fluid_settings_getint(settings2, "shell.port", &port2));
+    TEST_ASSERT(port2 >= FLUID_SHELL_AUTO_PORT_START && port2 <= FLUID_TCP_PORT_MAX);
+    TEST_ASSERT(port1 != port2);
+
+    delete_fluid_server(server2);
+    delete_fluid_server(server1);
+}
+
+int main(void)
+{
+#ifdef NETWORK_SUPPORT
+    fluid_settings_t *settings1, *settings2;
+    fluid_server_t *server1, *server2;
+
+    settings1 = new_fluid_settings();
+    settings2 = new_fluid_settings();
+    TEST_ASSERT(settings1 != NULL);
+    TEST_ASSERT(settings2 != NULL);
+
+    // by default, auto-port probing should be enabled
+    test_server_creation(settings1, settings2);
+
+    TEST_SUCCESS(fluid_settings_setint(settings1, "shell.port", 0));
+    TEST_SUCCESS(fluid_settings_setint(settings2, "shell.port", 0));
+
+    // re-test by explicitly setting port to zero, should still work
+    test_server_creation(settings1, settings2);
+
+    TEST_SUCCESS(fluid_settings_setint(settings1, "shell.port", 12345));
+    TEST_SUCCESS(fluid_settings_setint(settings2, "shell.port", 12345));
+
+    server1 = new_fluid_server2(settings1, NULL, NULL, NULL);
+    TEST_ASSERT(server1 != NULL);
+    server2 = new_fluid_server2(settings2, NULL, NULL, NULL);
+    TEST_ASSERT(server2 == NULL); // should fail since port 12345 is already in use by server1
+
+    delete_fluid_server(server2);
+    delete_fluid_server(server1);
+    delete_fluid_settings(settings2);
+    delete_fluid_settings(settings1);
+#endif
+
+    return EXIT_SUCCESS;
+}

Original file line number	Diff line number	Diff line change
`@@ -114,9 +114,10 @@ FLUIDSYNTH_API void delete_fluid_shell(fluid_shell_t *shell);`
`114`	`114`	`*`
`115`	`115`	`* TCP socket server for a command handler.`
`116`	`116`	`*`
`117`		`- * The socket server will open the TCP port set by \ref settings_shell_port`
`118`		`- * (default 9800) and starts a new thread and \ref command_handler for each`
`119`		`- * incoming connection.`
	`117`	`+ * The socket server will open the TCP port set by \ref settings_shell_port`
	`118`	`+ * (default 9800). If the setting is 0, the first free port is selected`
	`119`	`+ * automatically, probing from 9800 upwards. The server starts a new thread and`
	`120`	`+ * \ref command_handler for each incoming connection.`
`120`	`121`	`*`
`121`	`122`	`* @note The server is only available if libfluidsynth has been compiled`
`122`	`123`	`* with network support (enable-network). Without network support, all related`