ipc test for fm95

CMakeLists.txt

@@ -44,13 +44,13 @@ foreach(SRC_FILE ${SRC_FILES})
     target_compile_options(${EXEC_NAME} PRIVATE -O2 -Wall -Wextra -Werror -Wno-unused-parameter)
 
     if(EXEC_NAME STREQUAL "fm95")
-        target_link_libraries(${EXEC_NAME} PRIVATE libfmfilter libfmmodulation libfmdsp libfmio pulse pulse-simple m liquid inih)
+        target_link_libraries(${EXEC_NAME} PRIVATE libfmfilter libfmmodulation libfmdsp libfmio pulse pulse-simple m liquid inih pthread)
     elseif(EXEC_NAME STREQUAL "chimer95")
-        target_link_libraries(${EXEC_NAME} PRIVATE libfmdsp inih m libfmio pulse pulse-simple liquid)
+        target_link_libraries(${EXEC_NAME} PRIVATE libfmdsp inih m libfmio pulse pulse-simple liquid pthread)
     elseif(EXEC_NAME STREQUAL "sca95")
-        target_link_libraries(${EXEC_NAME} PRIVATE libfmmodulation inih m libfmio pulse pulse-simple libfmdsp liquid)
+        target_link_libraries(${EXEC_NAME} PRIVATE libfmmodulation inih m libfmio pulse pulse-simple libfmdsp liquid pthread)
     elseif(EXEC_NAME STREQUAL "vban95")
-        target_link_libraries(${EXEC_NAME} PRIVATE libfmio pulse pulse-simple liquid)
+        target_link_libraries(${EXEC_NAME} PRIVATE libfmio pulse pulse-simple liquid pthread)
     else()
         message(FATAL_ERROR "How do I link this? ${EXEC_NAME}")
     endif()

io/ipc.c

@@ -0,0 +1,96 @@
+#include "ipc.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <pthread.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+static int make_server_socket(const char *path)
+{
+    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (fd < 0) { perror("ipc: socket"); return -1; }
+
+    unlink(path);
+
+    struct sockaddr_un addr = { .sun_family = AF_UNIX };
+    strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1);
+
+    if (bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        perror("ipc: bind"); close(fd); return -1;
+    }
+    if (listen(fd, IPC_BACKLOG) < 0) {
+        perror("ipc: listen"); close(fd); return -1;
+    }
+    return fd;
+}
+
+static void *listener_thread(void *arg) {
+    ipc_ctx_t *ctx = (ipc_ctx_t *)arg;
+
+    while (ctx->running) {
+        struct sockaddr_un peer;
+        socklen_t peer_len = sizeof(peer);
+
+        int client_fd = accept(ctx->server_fd,
+                               (struct sockaddr *)&peer, &peer_len);
+        if (client_fd < 0) {
+            if (errno == EINVAL || errno == EBADF) break; /* shutting down */
+            if (errno == EINTR)                   continue;
+            perror("ipc: accept");
+            continue;
+        }
+
+        printf("[ipc] new client fd=%d\n", client_fd);
+
+        int *fd_ptr = malloc(sizeof(int));
+        if (!fd_ptr) { close(client_fd); continue; }
+        *fd_ptr = client_fd;
+
+        pthread_t tid;
+        if (pthread_create(&tid, NULL, ctx->handler, fd_ptr) != 0) {
+            perror("ipc: pthread_create");
+            free(fd_ptr);
+            close(client_fd);
+            continue;
+        }
+        pthread_detach(tid);
+    }
+
+    printf("[ipc] listener exiting\n");
+    return NULL;
+}
+
+int create_ipc(ipc_ctx_t *ctx, ipc_client_fn handler, const char* socket_path) {
+    ctx->handler = handler;
+    ctx->running = 1;
+    ctx->server_fd = make_server_socket(socket_path);
+    ctx->socket_path = strdup(socket_path);
+    if (ctx->server_fd < 0) return -1;
+
+    pthread_t tid;
+    if (pthread_create(&tid, NULL, listener_thread, ctx) != 0) {
+        perror("ipc: pthread_create");
+        close(ctx->server_fd);
+        unlink(socket_path);
+        return -1;
+    }
+
+    /* store tid so destroy_ipc can join it */
+    ctx->_tid = tid;
+
+    printf("[ipc] listening on %s\n", socket_path);
+    return 0;
+}
+
+void destroy_ipc(ipc_ctx_t *ctx) {
+    ctx->running = 0;
+    shutdown(ctx->server_fd, SHUT_RDWR); /* unblock accept() */
+    close(ctx->server_fd);
+    unlink(ctx->socket_path);
+    pthread_join(ctx->_tid, NULL);
+    printf("[ipc] shut down\n");
+}

io/ipc.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+#include <pthread.h>
+
+#define IPC_SOCKET_PATH "/tmp/ipc_demo.sock"
+#define IPC_BACKLOG 1
+
+typedef void *(*ipc_client_fn)(void *client_fd_ptr);
+
+typedef struct {
+    int server_fd;
+    volatile int running;
+    ipc_client_fn handler;
+    pthread_t _tid;       /* internal — do not touch */
+    const char* socket_path;
+} ipc_ctx_t;
+int create_ipc(ipc_ctx_t *ctx, ipc_client_fn handler, const char* socket_path);
+void destroy_ipc(ipc_ctx_t *ctx);

src/fm95.c

@@ -17,6 +17,7 @@
 #define BUFFER_SIZE 4998 // This defines how many samples to process at a time, because the loop here is this: get signal -> process signal -> output signal, and when we get signal we actually get BUFFER_SIZE of them
 
 #include "../io/audio.h"
+#include "../io/ipc.h"
 
 static volatile sig_atomic_t to_run = 1;
 static volatile sig_atomic_t to_reload = 0;
@@ -456,9 +457,38 @@ void init_runtime(FM95_Runtime* runtime, const FM95_Config config) {
 	}
 }
 
+#define BUF_SIZE 256
+static void *handle_client(void *arg) {
+    int fd = *(int *)arg;
+    free(arg);
+
+    char buf[BUF_SIZE];
+    ssize_t n;
+
+    while ((n = recv(fd, buf, sizeof(buf) - 1, 0)) > 0) {
+        buf[n] = '\0';
+        printf("[client fd=%d] %s\n", fd, buf);
+
+        char reply[BUF_SIZE];
+        snprintf(reply, sizeof(reply), "ECHO: %s", buf);
+        send(fd, reply, strlen(reply), 0);
+    }
+
+    printf("[client fd=%d] disconnected\n", fd);
+    close(fd);
+    return NULL;
+}
+
 int main(int argc, char **argv) {
 	printf("fm95 (an FM Processor by radio95) version 2.5\n");
 
+	ipc_ctx_t ctx = NULL;
+	if(create_ipc(&ctx, handle_client, "/etc/fm95/ctl.socket") < 0) {
+		printf("Could not create IPC.\n");
+		ctx = NULL;
+	}
+
+
 	FM95_Config config = {
 		.volumes = {
 			.pilot = 0.09f,
@@ -573,5 +603,6 @@ int main(int argc, char **argv) {
 		cleanup_audio_runtime(&runtime, config.options);
 		break;
 	}
+	if(ctx != NULL) destroy_ipc(&ctx);
 	return ret;
 }