From c8505367316e78f347935d859bad960830434774 Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Sat, 12 Aug 2023 20:06:14 +0900
Subject: [PATCH] WIP plugin listening on unix socket

TODO: Use a thread to listen on the socket.
---
 .gitignore            |  2 ++
 CMakeLists.txt        | 23 +++++++++++++++
 compile_commands.json |  1 +
 src/plugin.c          | 24 ++++++++++++++++
 src/socket.c          | 67 +++++++++++++++++++++++++++++++++++++++++++
 src/socket.h          | 42 +++++++++++++++++++++++++++
 6 files changed, 159 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 CMakeLists.txt
 create mode 120000 compile_commands.json
 create mode 100644 src/plugin.c
 create mode 100644 src/socket.c
 create mode 100644 src/socket.h

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5566193
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/.cache/
+/build*/
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..f84fa4c
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,23 @@
+cmake_minimum_required(VERSION 3.25)
+project(obs-studio-plugin-unix-socket-control)
+
+add_compile_options(
+    -Wall -Wextra -Wpedantic
+    $<$<CONFIG:DEBUG>:-O0>
+)
+
+if(NOT DEFINED CMAKE_BUILD_TYPE OR NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE "Debug")
+    message("Set build type to Debug by default")
+endif()
+
+set(unix-socket-control_SOURCES
+    src/plugin.c
+    src/socket.c
+)
+
+add_library(unix-socket-control MODULE
+    ${unix-socket-control_SOURCES})
+
+find_package(libobs REQUIRED)
+target_link_libraries(unix-socket-control PRIVATE OBS::libobs)
diff --git a/compile_commands.json b/compile_commands.json
new file mode 120000
index 0000000..71ca32f
--- /dev/null
+++ b/compile_commands.json
@@ -0,0 +1 @@
+buildDebug/compile_commands.json
\ No newline at end of file
diff --git a/src/plugin.c b/src/plugin.c
new file mode 100644
index 0000000..68adc95
--- /dev/null
+++ b/src/plugin.c
@@ -0,0 +1,24 @@
+// plugin includes
+#include <obs-module.h>
+#include <obs-frontend-api.h>
+
+// local includes
+#include "socket.h"
+
+static UnixSocketHandler global_unix_socket_handler={
+    .flags = 0xFFFFFFFFFFFFFFFF
+};
+
+OBS_DECLARE_MODULE()
+
+OBS_MODULE_USE_DEFAULT_LOCALE("unix-socket-control", "en-US")
+
+bool obs_module_load(void) {
+    global_unix_socket_handler = init_unix_socket_handler();
+
+    return is_unix_socket_handler_valid(global_unix_socket_handler) ? true : false;
+}
+
+void obs_module_unload(void) {
+    cleanup_unix_socket_handler(&global_unix_socket_handler);
+}
diff --git a/src/socket.c b/src/socket.c
new file mode 100644
index 0000000..7bfc3cf
--- /dev/null
+++ b/src/socket.c
@@ -0,0 +1,67 @@
+#include "socket.h"
+
+// standard library includes
+#include <stdlib.h>
+
+// unix includes
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define UNIX_SOCKET_HANDLER_SOCKET_NAME "/tmp/obs-studio-plugin-unix-socket-handler-socket"
+
+UnixSocketHandler init_unix_socket_handler(void) {
+    UnixSocketHandler handler;
+
+    memset(&handler, 0, sizeof(UnixSocketHandler));
+
+    umask(S_IRWXO);
+
+    // Set up linked list of events.
+    handler.events_head.next = &handler.events_tail;
+    handler.events_tail.prev = &handler.events_head;
+
+    handler.events_head.type = UNIX_SOCKET_EVENT_HEAD;
+    handler.events_tail.type = UNIX_SOCKET_EVENT_TAIL;
+
+    // Set up unix socket.
+    handler.socket_descriptor = socket(AF_UNIX, SOCK_SEQPACKET, 0);
+    if (handler.socket_descriptor == -1) {
+        handler.flags = 0xFFFFFFFFFFFFFFFF;
+        return handler;
+    }
+
+    handler.name.sun_family = AF_UNIX;
+    strncpy(handler.name.sun_path,
+            UNIX_SOCKET_HANDLER_SOCKET_NAME,
+            sizeof(handler.name.sun_path) - 1);
+
+    int ret = bind(handler.socket_descriptor,
+                   (const struct sockaddr*) &handler.name,
+                   sizeof(handler.name));
+    if (ret == -1) {
+        close(handler.socket_descriptor);
+        handler.socket_descriptor = -1;
+        handler.flags = 0xFFFFFFFFFFFFFFFF;
+        return handler;
+    }
+
+    return handler;
+}
+
+void cleanup_unix_socket_handler(UnixSocketHandler *handler) {
+    if (handler->flags == 0xFFFFFFFFFFFFFFFF) {
+        return;
+    }
+
+    if (handler->socket_descriptor >= 0) {
+        close(handler->socket_descriptor);
+        handler->socket_descriptor = -1;
+        unlink(UNIX_SOCKET_HANDLER_SOCKET_NAME);
+    }
+    handler->flags = 0xFFFFFFFFFFFFFFFF;
+}
+
+int is_unix_socket_handler_valid(UnixSocketHandler handler) {
+    return handler.flags == 0xFFFFFFFFFFFFFFFF ? 0 : 1;
+}
diff --git a/src/socket.h b/src/socket.h
new file mode 100644
index 0000000..78d1560
--- /dev/null
+++ b/src/socket.h
@@ -0,0 +1,42 @@
+#ifndef OBS_STUDIO_PLUGIN_UNIX_SOCKET_CONTROL_SOCKET_H_
+#define OBS_STUDIO_PLUGIN_UNIX_SOCKET_CONTROL_SOCKET_H_
+
+// standard library includes
+#include <stdint.h>
+
+// unix includes
+#include <sys/socket.h>
+#include <sys/un.h>
+
+typedef enum UnixSocketEventType {
+    UNIX_SOCKET_EVENT_NOP,
+    UNIX_SOCKET_EVENT_HEAD,
+    UNIX_SOCKET_EVENT_TAIL,
+    UNIX_SOCKET_EVENT_START_RECORDING,
+    UNIX_SOCKET_EVENT_STOP_RECORDING,
+    UNIX_SOCKET_EVENT_START_STREAMING,
+    UNIX_SOCKET_EVENT_STOP_STREAMING
+} UnixSocketEventType;
+
+typedef struct UnixSocketEvent {
+    struct UnixSocketEvent *next;
+    struct UnixSocketEvent *prev;
+    UnixSocketEventType type;
+} UnixSocketEvent;
+
+typedef struct UnixSocketHandler {
+    /*
+     * All ones - invalid/cleaned-up instance
+     */
+    uint64_t flags;
+    UnixSocketEvent events_head;
+    UnixSocketEvent events_tail;
+    struct sockaddr_un name;
+    int socket_descriptor;
+} UnixSocketHandler;
+
+UnixSocketHandler init_unix_socket_handler(void);
+void cleanup_unix_socket_handler(UnixSocketHandler *handler);
+int is_unix_socket_handler_valid(UnixSocketHandler handler);
+
+#endif