server: Add plugin framework

7 files changed, 172 insertions, 21 deletions

diff --git a/Makefile b/Makefile
index 8922662..307fbfa 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,13 @@
 CC = gcc
-CFLAGS = -Wall -Wextra -std=c11 -g -fwrapv
-LDFLAGS = -lsqlite3
+CFLAGS = -Wall -Wextra -std=c11 -g -fwrapv -D_BSD_SOURCE
+LDFLAGS = -lsqlite3 -ldl
 
 TARGETS = tomsg_server
 
+PLUGINDIR = plugins
+
+PLUGINS = $(patsubst $(PLUGINDIR)/%,%,$(shell find $(PLUGINDIR)/ -maxdepth 1 -type d))
+
 .PHONY: all clean remake
 
 # Clear all implicit suffix rules
@@ -13,9 +17,11 @@ TARGETS = tomsg_server
 .SECONDARY:
 
 all: $(TARGETS)
+	for pl in $(PLUGINS); do make --no-print-directory -C $(PLUGINDIR) $@ PLUGINNAME=$$pl; done
 
 clean:
 	rm -f $(TARGETS) *.o *.sql.h
+	for pl in $(PLUGINS); do make --no-print-directory -C $(PLUGINDIR) $@ PLUGINNAME=$$pl; done
 
 remake: clean
 	$(MAKE) all
diff --git a/main.c b/main.c
index a754f02..5028190 100644
--- a/main.c
+++ b/main.c
@@ -13,6 +13,7 @@
 #include "db.h"
 #include "event.h"
 #include "net.h"
+#include "plugin.h"
 #include "runloop.h"
 #include "user_data.h"
 
@@ -146,34 +147,21 @@ void srandomdev(void){
 }
 #endif
 
-__attribute__((unused))
-static void dummy_event_handler(const struct event_item *event){
-	switch(event->type){
-		case EVENT_MESSAGE:
-			debug("event: <%s>@%s: %s",event->user,event->room,event->message);
-			break;
-
-		case EVENT_ONLINE:
-			debug("event: <%s> online=%" PRIi64,event->user,event->num);
-			break;
+int main(int argc,char **argv){
+	srandomdev();
 
-		case EVENT_JOIN:
-			debug("event: <%s> joins %s",event->user,event->room);
-			break;
+	plugin_init();
+	for(int i=1;i<argc;i++){
+		plugin_register(argv[i]);
 	}
-}
-
-int main(void){
-	srandomdev();
+	if(argc<=1)printf("Loaded no plugins\n");
 
 	db_init();
 	int sock=create_server_socket();
 	printf("Listening on port %d\n",PORT);
-	// event_register(dummy_event_handler);
 	runloop_set_timeout(60*1000000,timeout_callback);
 	runloop_add_fd(sock,server_socket_callback,false);
 	runloop_run();
 	printf("Runloop empty, shutting down\n");
-	// event_unregister(dummy_event_handler);
 	db_close();
 }
diff --git a/plugin.c b/plugin.c
new file mode 100644
index 0000000..14dce01
--- /dev/null
+++ b/plugin.c
@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <string.h>
+#include <dlfcn.h>
+#include "event.h"
+#include "global.h"
+#include "plugin.h"
+#include "plugin_client_header.h"
+
+
+struct plugin_data{
+	void *handle;
+	plugin_event_func_t *callback;
+};
+
+static i64 num_plugins=0;
+static i64 plugins_cap=8;
+static struct plugin_data *plugins_list=NULL;
+
+
+static void consume_event(const struct event_item *event){
+	struct plugin_event pe;
+	switch(event->type){
+		case EVENT_MESSAGE: pe.type=PLUGIN_EVENT_MESSAGE; break;
+		case EVENT_ONLINE: pe.type=PLUGIN_EVENT_ONLINE; break;
+		case EVENT_JOIN: pe.type=PLUGIN_EVENT_JOIN; break;
+		default:
+			die("Unknown event type %d in plugin.c:consume_event",event->type);
+	}
+	pe.timestamp=event->timestamp;
+	pe.message=event->message;
+	pe.user=event->user;
+	pe.room=event->room;
+	pe.num=event->num;
+
+	for(i64 i=0;i<num_plugins;i++){
+		plugins_list[i].callback(&pe);
+	}
+}
+
+
+void plugin_init(void){
+	if(plugins_list!=NULL)return;
+	plugins_list=malloc(plugins_cap,struct plugin_data);
+	memset(plugins_list,0,num_plugins*sizeof(struct plugin_data));
+
+	event_register(consume_event);
+}
+
+void plugin_register(const char *fname){
+	if(num_plugins==plugins_cap){
+		plugins_cap*=2;
+		plugins_list=realloc(plugins_list,plugins_cap,struct plugin_data);
+	}
+
+	struct plugin_data *data=plugins_list+num_plugins;
+	num_plugins++;
+	data->handle=dlopen(fname,RTLD_NOW|RTLD_LOCAL);
+	if(data->handle==NULL){
+		die("Error loading plugin '%s': %s",fname,dlerror());
+	}
+
+	plugin_event_func_t* (*init_func)(void)=NULL;
+	dlerror();
+	*(void**)&init_func=dlsym(data->handle,"plugin_init_func");
+	char *err=dlerror();
+	if(err!=NULL){
+		die("Error reading symbol 'plugin_init_func' from plugin '%s'",fname);
+	}
+	if(init_func==NULL){
+		die("Plugin '%s' exports NULL init function",fname);
+	}
+
+	data->callback=init_func();
+	if(data->callback==NULL){
+		die("Init function of plugin '%s' returned NULL",fname);
+	}
+
+	printf("Loaded plugin '%s'\n",fname);
+}
diff --git a/plugin.h b/plugin.h
new file mode 100644
index 0000000..de235c9
--- /dev/null
+++ b/plugin.h
@@ -0,0 +1,7 @@
+#pragma once
+
+
+void plugin_init(void);
+
+// Pass path to a shared object file / dynamic library
+void plugin_register(const char *fname);
diff --git a/plugin_client_header.h b/plugin_client_header.h
new file mode 100644
index 0000000..4428b3c
--- /dev/null
+++ b/plugin_client_header.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include <stdint.h>
+
+
+enum plugin_event_type{
+	PLUGIN_EVENT_MESSAGE,  // message, user, room
+	PLUGIN_EVENT_ONLINE,  // user, num
+	PLUGIN_EVENT_JOIN,  // user, room
+};
+
+struct plugin_event{
+	enum plugin_event_type type;
+	int64_t timestamp;  // always set
+	char *message,*user,*room;
+	int64_t num;
+};
+
+
+typedef void plugin_event_func_t(const struct plugin_event *event);
+
+
+// All plugins should export a function of type plugin_init_func_t with
+// name "plugin_init_func" that returns a pointer to a function that
+// receives all events.
+plugin_event_func_t* plugin_init_func(void);
diff --git a/plugins/Makefile b/plugins/Makefile
new file mode 100644
index 0000000..0824f2e
--- /dev/null
+++ b/plugins/Makefile
@@ -0,0 +1,34 @@
+CC = gcc
+CFLAGS = -Wall -Wextra -std=c11 -g -fwrapv -I.. -fPIC
+
+ifeq ($(shell uname),Darwin)
+	SO_EXT = dylib
+	SO_FLAGS = -dynamiclib
+else
+	SO_EXT = so
+	SO_FLAGS = -shared
+endif
+SO_FLAGS += -fPIC
+
+TARGET = $(PLUGINNAME)/$(PLUGINNAME).$(SO_EXT)
+
+
+.PHONY: all clean remake warning
+
+all: warning $(TARGET)
+
+clean: warning
+	rm -rf $(TARGET) $(PLUGINNAME)/*.{o,dSYM}
+
+remake: clean all
+
+warning:
+ifndef PLUGINNAME
+	$(error "PLUGINNAME not set! Please run root Makefile instead.")
+endif
+
+
+.SECONDARY:
+
+$(PLUGINNAME)/%.$(SO_EXT): $(patsubst %.c,%.o,$(wildcard $(PLUGINNAME)/*.c)) $(wildcard ../*.h)
+	$(CC) $(SO_FLAGS) -o $@ $(filter %.o,$^)
diff --git a/plugins/log/main.c b/plugins/log/main.c
new file mode 100644
index 0000000..b931d12
--- /dev/null
+++ b/plugins/log/main.c
@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include "plugin_client_header.h"
+
+
+static void eventfunc(const struct plugin_event *event){
+	printf("type = %d\n",event->type);
+}
+
+plugin_event_func_t* plugin_init_func(void){
+	return eventfunc;
+}