module-jack: load libjack.so.0 with dlopen

This way we can search for the real jack library instead of using our custom libjack.so. Add an option to override the search path with LIBJACK_PATH and an option to select the library name to load.
2025-11-05 13:30:02 -05:00 · 2023-05-05 15:42:14 +02:00 · 2023-05-05 15:42:14 +02:00 · 0629647cb5
commit 0629647cb5
parent 7da4eb13f7
3 changed files with 228 additions and 35 deletions
--- a/src/modules/module-jack-tunnel/weakjack.h
+++ b/src/modules/module-jack-tunnel/weakjack.h
@ -0,0 +1,179 @@
+/* PipeWire */
+/* SPDX-FileCopyrightText: Copyright © 2023 Wim Taymans */
+/* SPDX-License-Identifier: MIT */
+
+#ifndef PIPEWIRE_WEAK_JACK_H
+#define PIPEWIRE_WEAK_JACK_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "config.h"
+
+#include <dlfcn.h>
+
+#include <jack/jack.h>
+#include <jack/transport.h>
+
+struct weakjack {
+	jack_nframes_t (*cycle_wait) (jack_client_t* client);
+	void (*cycle_signal) (jack_client_t* client, int status);
+
+	jack_nframes_t (*frame_time) (const jack_client_t *);
+	int (*get_cycle_times) (const jack_client_t *client,
+			jack_nframes_t *current_frames,
+			jack_time_t    *current_usecs,
+			jack_time_t    *next_usecs,
+			float          *period_usecs);
+	jack_transport_state_t (*transport_query) (const jack_client_t *client,
+                                             jack_position_t *pos);
+
+	jack_client_t * (*client_open) (const char *client_name,
+                                  jack_options_t options,
+                                  jack_status_t *status, ...);
+	int (*client_close) (jack_client_t *client);
+
+
+	int (*activate) (jack_client_t *client);
+	int (*deactivate) (jack_client_t *client);
+
+	jack_nframes_t (*get_sample_rate) (jack_client_t *);
+
+	int (*recompute_total_latencies) (jack_client_t *client);
+
+	jack_port_t * (*port_register) (jack_client_t *client,
+			const char *port_name,
+			const char *port_type,
+			unsigned long flags,
+			unsigned long buffer_size);
+	int (*port_unregister) (jack_client_t *client, jack_port_t *port);
+	void * (*port_get_buffer) (jack_port_t *port, jack_nframes_t);
+	const char * (*port_name) (const jack_port_t *port);
+
+	void (*port_get_latency_range) (jack_port_t *port,
+			jack_latency_callback_mode_t mode,
+			jack_latency_range_t *range);
+	void (*port_set_latency_range) (jack_port_t *port,
+			jack_latency_callback_mode_t mode,
+			jack_latency_range_t *range);
+
+
+	int (*connect) (jack_client_t *client,
+			const char *source_port,
+			const char *destination_port);
+	int (*disconnect) (jack_client_t *client,
+			const char *source_port,
+			const char *destination_port);
+
+	const char ** (*get_ports) (jack_client_t *client,
+			const char *port_name_pattern,
+			const char *type_name_pattern,
+			unsigned long flags);
+	void (*free) (void* ptr);
+
+	int (*set_process_thread) (jack_client_t* client,
+			JackThreadCallback thread_callback, void *arg);
+	int (*set_xrun_callback) (jack_client_t *client,
+			JackXRunCallback xrun_callback, void *arg);
+	void (*on_info_shutdown) (jack_client_t *client,
+			JackInfoShutdownCallback shutdown_callback, void *arg);
+	int (*set_latency_callback) (jack_client_t *client,
+			JackLatencyCallback latency_callback, void *arg);
+};
+
+
+static inline int weakjack_load_by_path(struct weakjack *jack, const char *path)
+{
+	void *hnd;
+
+	hnd = dlopen(path, RTLD_NOW);
+	if (hnd == NULL)
+		return -errno;
+
+	pw_log_info("opened libjack: %s", path);
+
+#define LOAD_SYM(name) ({					\
+	if ((jack->name =  dlsym(hnd, "jack_"#name )) == NULL)	\
+		return -ENOSYS;					\
+})
+	spa_zero(*jack);
+	LOAD_SYM(cycle_wait);
+	LOAD_SYM(cycle_signal);
+	LOAD_SYM(frame_time);
+	LOAD_SYM(get_cycle_times);
+	LOAD_SYM(transport_query);
+
+	LOAD_SYM(client_open);
+	LOAD_SYM(client_close);
+
+	LOAD_SYM(activate);
+	LOAD_SYM(deactivate);
+
+	LOAD_SYM(get_sample_rate);
+
+	LOAD_SYM(recompute_total_latencies);
+
+	LOAD_SYM(port_register);
+	LOAD_SYM(port_unregister);
+	LOAD_SYM(port_get_buffer);
+	LOAD_SYM(port_name);
+
+	LOAD_SYM(port_get_latency_range);
+	LOAD_SYM(port_set_latency_range);
+
+	LOAD_SYM(connect);
+	LOAD_SYM(disconnect);
+
+	LOAD_SYM(get_ports);
+	LOAD_SYM(free);
+
+	LOAD_SYM(set_process_thread);
+	LOAD_SYM(set_xrun_callback);
+	LOAD_SYM(on_info_shutdown);
+	LOAD_SYM(set_latency_callback);
+#undef LOAD_SYM
+
+	return 0;
+}
+
+static inline int weakjack_load(struct weakjack *jack, const char *lib)
+{
+	int res = -ENOENT;
+
+	if (lib[0] != '/') {
+		const char *search_dirs, *p, *state = NULL;
+		char path[PATH_MAX];
+		size_t len;
+
+		search_dirs = getenv("LIBJACK_PATH");
+		if (!search_dirs)
+			search_dirs = "/usr/lib64:/usr/lib/:" LIBDIR;
+
+
+		while ((p = pw_split_walk(search_dirs, ":", &len, &state))) {
+			int pathlen;
+
+			if (len >= sizeof(path)) {
+				res = -ENAMETOOLONG;
+				continue;
+			}
+			pathlen = snprintf(path, sizeof(path), "%.*s/%s", (int) len, p, lib);
+			if (pathlen < 0 || (size_t) pathlen >= sizeof(path)) {
+				res = -ENAMETOOLONG;
+				continue;
+			}
+			if ((res = weakjack_load_by_path(jack, path)) == 0)
+				break;
+		}
+	} else {
+		res = weakjack_load_by_path(jack, lib);
+	}
+	return res;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PIPEWIRE_WEAK_JACK_H */