From 097ddb404f2a67398821c6a27f24db5cb939b79d Mon Sep 17 00:00:00 2001
From: Trumeet <yuuta@yuuta.moe>
Date: Thu, 8 Jul 2021 21:20:11 -0700
Subject: feat: require a string unique ID as plugin identification

This greatly simplifies the management of plugins, but no longer supports loading the same plugin twice.
---
 main.c            | 27 ++++++----------------
 plugin/plugin.h   |  5 +++-
 plugin_registry.c | 68 ++++++++++++++++++++++++++++---------------------------
 plugin_registry.h |  9 ++++----
 plugins.c         | 43 +++++++++++++++++++++++++----------
 plugins.h         |  8 ++++---
 sample/main.c     | 33 ++++++++++++++-------------
 7 files changed, 104 insertions(+), 89 deletions(-)

diff --git a/main.c b/main.c
index 608c10f..591d022 100644
--- a/main.c
+++ b/main.c
@@ -95,9 +95,8 @@ static int autoload(const char *config_path)
 		current_path[strlen(current_path) - 1] = '\0';
 		if(strlen(current_path) > 0)
 		{
-			int id = 0;
-			if(!plugin_registry_load(2, current_path, &id))
-				printf(_("Autoload: loaded %s with ID %d.\n"), current_path, id);
+			if(!plugin_registry_load(2, current_path))
+				printf(_("Autoload: loaded %s.\n"), current_path);
 		}
 		free(current_path);
 	}
@@ -182,7 +181,7 @@ static int main_handle_cmd(const int out, int argc, char **argv)
 		for(int i = 0; i < plugin_size(); i ++)
 		{
 			const struct plugin *plug = plugin_get_by_index(i);
-			dprintf(out, _("%d\t%s\n"), plug->id, plug->name);
+			dprintf(out, _("%s\t%s\n"), plug->id, plug->name);
 		}
 		return 0;
 	}
@@ -196,12 +195,7 @@ static int main_handle_cmd(const int out, int argc, char **argv)
 		dprintf(out, _("Waiting until the processing is done.\n"));
 		exclusive_section_enter();
 		thpool_wait(thpool);
-		int id = -1;
-		int r = plugin_registry_load(out, argv[1], &id);
-		if(!r)
-		{
-			dprintf(out, _("ID: %d\n"), id);
-		}
+		int r = plugin_registry_load(out, argv[1]);
 		exclusive_section_leave();
 		return r;
 	}
@@ -212,14 +206,7 @@ static int main_handle_cmd(const int out, int argc, char **argv)
 			dprintf(out, _("unload expects one argument: unload <ID>\n"));
 			return 64;
 		}
-	        char *endptr;
-	        intmax_t num = strtoimax(argv[1], &endptr, 10);
-	        if(strcmp(endptr, "") || (num == INTMAX_MAX && errno == ERANGE) || num > INT_MAX || num < INT_MIN)
-		{
-			dprintf(out, _("Invalid ID: %s\n"), argv[1]);
-			return 64;
-		}
-		int id = (int)num;
+		char *id = argv[1];
 		dprintf(out, _("Waiting until the processing is done.\n"));
 		int r = 0;
 		exclusive_section_enter();
@@ -228,7 +215,7 @@ static int main_handle_cmd(const int out, int argc, char **argv)
 		if(plug == NULL)
 		{
 			r = 1;
-			dprintf(out, _("Cannot find plugin ID: %d\n"), id);
+			dprintf(out, _("Cannot find plugin ID: %s\n"), id);
 		}
 		else
 		{
@@ -657,7 +644,7 @@ cleanup:
 	if(autoload_setup) {} // Plugins are always unloaded.
 	DEBUG("main.c#main_daemon: Unloading plugins...\n");
 	const int size = plugin_size();
-	int *plugins = calloc(size, sizeof(int));
+	const char **plugins = calloc(size, sizeof(char*));
 	for(int i = 0; i < size; i ++)
 		plugins[i] = plugin_get_by_index(i)->id;
 	for(int i = 0; i < size; i ++)
diff --git a/plugin/plugin.h b/plugin/plugin.h
index bfed63d..e52c62f 100644
--- a/plugin/plugin.h
+++ b/plugin/plugin.h
@@ -17,10 +17,13 @@ extern const uint32_t epg_version;
 /* Plugin display name. */
 extern const char *epg_name;
 
+/* NULL terminated unique ID */
+extern const char *epg_id;
+
 /* Current session handle. */
 struct epg_handle {
 	/* Unique ID. */
-	int id;
+	const char *id;
 	/* Send rcon command. */
 	int (*rcon_send)(int, char *);
 	int (*rcon_recv)(int *, char *);
diff --git a/plugin_registry.c b/plugin_registry.c
index b6b0dbd..b6ace57 100644
--- a/plugin_registry.c
+++ b/plugin_registry.c
@@ -12,31 +12,21 @@
 #define PLUGIN_ID_GEN_MAX_RETRY 1
 
 static int plugin_count = 0;
+/* TODO: May use hashing to improve search preformance */
+/* TODO: May use sorting + binary search to improve search performance */
+static const char **id_arr = NULL;
 static struct plugin *plugin_arr = NULL;
 static pthread_key_t key_plugin;
 
-static int plugin_generate_id()
-{
-	int retry_count = 0;
-	goto gen;
-gen:
-	if(retry_count > PLUGIN_ID_GEN_MAX_RETRY) return -1;
-	int rand_val = rand();
-	for(int i = 0; i < plugin_count; i ++)
-	{
-		if(plugin_get_by_index(i)->id == rand_val)
-		{
-			retry_count ++;
-			goto gen;
-		}
-	}
-	return rand_val;
-}
-
 static void arr_resize(int new_size)
 {
 	if(new_size == 0)
 	{
+		if(id_arr != NULL)
+		{
+			free(id_arr);
+			id_arr = NULL;
+		}
 		if(plugin_arr != NULL)
 		{
 			free(plugin_arr);
@@ -44,6 +34,10 @@ static void arr_resize(int new_size)
 		}
 		return;
 	}
+	if(id_arr == NULL)
+		id_arr = calloc(new_size, sizeof(char *));
+	else
+		id_arr = realloc(id_arr, new_size * sizeof(char *));
 	if(plugin_arr == NULL)
 		plugin_arr = calloc(new_size, sizeof(struct plugin));
 	else
@@ -68,17 +62,17 @@ int plugin_size()
 	return plugin_count;
 }
 
-static int plugin_id_to_index(int id)
+static int plugin_id_to_index(const char *id)
 {
 	for(int i = 0; i < plugin_count; i ++)
 	{
-		if(plugin_arr[i].id == id)
+		if(!strcmp(id_arr[i], id))
 			return i;
 	}
 	return -1;
 }
 
-struct plugin *plugin_get(int id)
+struct plugin *plugin_get(const char *id)
 {
 	const int index = plugin_id_to_index(id);
 	if(index < 0)
@@ -91,7 +85,7 @@ struct plugin *plugin_get_by_index(int index)
 	return &plugin_arr[index];
 }
 
-int plugin_registry_unload(int stderr_fd, int id)
+int plugin_registry_unload(int stderr_fd, const char *id)
 {
 	int r = 0;
 	const int index = plugin_id_to_index(id);
@@ -103,30 +97,38 @@ int plugin_registry_unload(int stderr_fd, int id)
 	struct plugin *plug = plugin_get_by_index(index);
 	r = plugin_unload(stderr_fd, plug);
 	if(r) goto cleanup;
+	r = plugin_unload_meta(stderr_fd, plug);
+	if(r) goto cleanup;
 	memcpy(plug, &plugin_arr[index + 1], (plugin_count - 1 - index) * sizeof(struct plugin));
+	memcpy((char **)id_arr[index], &id_arr[index + 1], (plugin_count - 1 - index) * sizeof(char *));
 	arr_resize(-- plugin_count);
 	goto cleanup;
 cleanup:
 	return r;
 }
 
-int plugin_registry_load(int stderr_fd, const char *path, int *id)
+int plugin_registry_load(int stderr_fd, const char *path)
 {
 	int r = 0;
-	const int id_gen = plugin_generate_id();
-	if(id_gen <= 0)
+	struct plugin plugin;
+	r = plugin_load_meta(stderr_fd, path, &plugin);
+	if(r) goto cleanup;
+	if(plugin_get(plugin.id) != NULL)
 	{
-		r = EPLUGINEXCEED;
+		dprintf(stderr_fd, _("Plugin '%s' exists.\n"), plugin.id);
+		plugin_unload_meta(stderr_fd, &plugin);
+		r = EPLUGINEXISTS;
 		goto cleanup;
 	}
-	arr_resize(++ plugin_count);
-	r = plugin_load(stderr_fd, path, id_gen, &plugin_arr[plugin_count - 1]);
+	r = plugin_load(stderr_fd, &plugin);
 	if(r)
 	{
-		arr_resize(-- plugin_count);
+		plugin_unload_meta(stderr_fd, &plugin);
 		goto cleanup;
 	}
-	*id = id_gen;
+	arr_resize(++ plugin_count);
+	id_arr[plugin_count - 1] = plugin.id;
+	memcpy(&plugin_arr[plugin_count - 1], &plugin, sizeof(struct plugin));
 	goto cleanup;
 cleanup:
 	return r;
@@ -136,7 +138,7 @@ static int api_rcon_send_wrapper(int pkt_id, char *command)
 {
 	int r = 0;
 	const struct plugin *plug = pthread_getspecific(key_plugin);
-	printf(_("[rcon#%d] -> '%s' (%d)\n"),
+	printf(_("[rcon#%s] -> '%s' (%d)\n"),
 			plug->id,
 			command,
 			pkt_id);
@@ -154,7 +156,7 @@ static int api_rcon_recv_wrapper(int *pkt_id, char *out)
 	// TODO: The plugin identity may have future usages.
 	r = rcon_host_recv(pkt_id, out);
 	if(!r)
-		printf(_("[rcon#%d] <- %s (%d)\n"),
+		printf(_("[rcon#%s] <- %s (%d)\n"),
 				plug->id,
 				out,
 				*pkt_id);
@@ -163,7 +165,7 @@ cleanup:
 	return r;
 }
 
-void plugcall_setup_handle(struct plugin *plugin, struct epg_handle *handle)
+void plugcall_setup_handle(const struct plugin *plugin, struct epg_handle *handle)
 {
 	pthread_setspecific(key_plugin, plugin);
 	handle->id = plugin->id;
diff --git a/plugin_registry.h b/plugin_registry.h
index a38808e..bc0ed18 100644
--- a/plugin_registry.h
+++ b/plugin_registry.h
@@ -5,17 +5,18 @@
 
 #define EPLUGINEXCEED	10
 #define EPLUGINNOTFOUND	74
+#define EPLUGINEXISTS	117
 
 int plugin_registry_init();
 void plugin_registry_free();
 
 int plugin_size();
-struct plugin *plugin_get(int id);
+struct plugin *plugin_get(const char *id);
 struct plugin *plugin_get_by_index(int index);
-int plugin_registry_unload(int stderr_fd, int id);
-int plugin_registry_load(int stderr_fd, const char *path, int *id);
+int plugin_registry_unload(int stderr_fd, const char *id);
+int plugin_registry_load(int stderr_fd, const char *path);
 
-void plugcall_setup_handle(struct plugin *plugin, struct epg_handle *handle);
+void plugcall_setup_handle(const struct plugin *plugin, struct epg_handle *handle);
 
 void plugcall_player_join(void *arg);
 void plugcall_player_leave(void *arg);
diff --git a/plugins.c b/plugins.c
index ec8b727..d7d81a1 100644
--- a/plugins.c
+++ b/plugins.c
@@ -26,7 +26,17 @@ static const void *plugin_dlsym(int stderr_fd, void *handle, const bool mandator
 	return sym;
 }
 
-int plugin_unload(int stderr_fd, struct plugin *plugin)
+int plugin_unload_meta(int stderr_fd, struct plugin *plugin)
+{
+	if(plugin->handle != NULL)
+	{
+		dlclose(plugin->handle);
+		plugin->handle = NULL;
+	}
+	return 0;
+}
+
+int plugin_unload(int stderr_fd, const struct plugin *plugin)
 {
 	if(plugin->fc_unload != NULL)
 	{
@@ -39,11 +49,6 @@ int plugin_unload(int stderr_fd, struct plugin *plugin)
 			return unload_r;
 		}
 	}
-	if(plugin->handle != NULL)
-	{
-		dlclose(plugin->handle);
-		plugin->handle = NULL;
-	}
 	return 0;
 }
 
@@ -51,6 +56,13 @@ static int plugin_load_v1(int stderr_fd, struct plugin *out)
 {
 	int r = 0;
 	const void *sym;
+	sym = plugin_dlsym(stderr_fd, out->handle, true, "epg_id");
+	if(sym == NULL)
+	{
+		r = 64;
+		goto cleanup;
+	}
+	out->id = *(char**)sym;
 	sym = plugin_dlsym(stderr_fd, out->handle, true, "epg_name");
 	if(sym == NULL)
 	{
@@ -75,10 +87,9 @@ cleanup:
 	return r;
 }
 
-int plugin_load(int stderr_fd, const char *path, const int id, struct plugin *out)
+int plugin_load_meta(int stderr_fd, const char *path, struct plugin *out)
 {
 	int r = 0;
-	out->id = id;
 	out->path = path;
 	out->handle = NULL;
 	out->name = NULL;
@@ -121,16 +132,24 @@ int plugin_load(int stderr_fd, const char *path, const int id, struct plugin *ou
 			dprintf(stderr_fd, _("Unsupported plugin %s: Incompatible with version %u.\n"), path, out->version);
 			break;
 	}
+	goto cleanup;
+cleanup:
+	if(r) plugin_unload_meta(stderr_fd, out);
+	return r;
+}
+
+int plugin_load(int stderr_fd, const struct plugin *plugin)
+{
+	int r = 0;
 	struct epg_handle hdl;
-	plugcall_setup_handle(out, &hdl);
-	r = out->fc_load(&hdl);
+	plugcall_setup_handle(plugin, &hdl);
+	r = plugin->fc_load(&hdl);
 	if(r)
 	{
 		dprintf(stderr_fd, _("Cannot load plugin: it returned an error: %d.\n"), r);
 		goto cleanup;
 	}
-	goto cleanup;
 cleanup:
-	if(r) plugin_unload(stderr_fd, out);
+	if(r) plugin_unload(stderr_fd, plugin);
 	return r;
 }
diff --git a/plugins.h b/plugins.h
index 64ab0bb..6ce4707 100644
--- a/plugins.h
+++ b/plugins.h
@@ -13,7 +13,7 @@ struct plugin_call_job_args {
 };
 
 struct plugin {
-	int id;
+	const char *id;
 	const char *path;
 	void *handle;
 	char *name;
@@ -32,7 +32,9 @@ struct plugin {
 	int (*fc_server_started)(struct epg_handle *, char *);
 };
 
-int plugin_load(int stderr_fd, const char *path, const int id, struct plugin *out);
-int plugin_unload(int stderr_fd, struct plugin *plugin);
+int plugin_load_meta(int stderr_fd, const char *path, struct plugin *out);
+int plugin_load(int stderr_fd, const struct plugin *plugin);
+int plugin_unload_meta(int stderr_fd, struct plugin *plugin);
+int plugin_unload(int stderr_fd, const struct plugin *plugin);
 
 #endif // _PLUGINS_H
diff --git a/sample/main.c b/sample/main.c
index 710d245..27e5bc3 100644
--- a/sample/main.c
+++ b/sample/main.c
@@ -7,38 +7,39 @@
 const uint32_t epg_version = 1;
 
 const char *epg_name = "Test Plugin";
+const char *epg_id = "test";
 
 int epg_load(struct epg_handle *handle)
 {
-	printf("[%d]: Loaded.\n", handle->id);
+	printf("[%s]: Loaded.\n", handle->id);
 	int r = 0;
 	r = handle->rcon_send(11, "list uuid");
-	printf("[%d]: rcon_send: %d\n", handle->id, r);
+	printf("[%s]: rcon_send: %d\n", handle->id, r);
 	int id = -1;
 	char out[RCON_DATA_BUFFSIZE];
 	r = handle->rcon_recv(&id, out);
-	printf("[%d]: rcon_recv: %d. ID: %d, out: '%s'.\n", handle->id, r, id, out);
+	printf("[%s]: rcon_recv: %d. ID: %d, out: '%s'.\n", handle->id, r, id, out);
 	return 0;
 }
 
 int epg_unload(struct epg_handle *handle)
 {
-	printf("[%d]: Unloading.\n", handle->id);
+	printf("[%s]: Unloading.\n", handle->id);
 	return 0;
 }
 
 int epg_player_join(struct epg_handle *handle,
 		char *player)
 {
-	printf("[%d]: %s joined.\n", handle->id, player);
+	printf("[%s]: %s joined.\n", handle->id, player);
 	sleep(10);
 	int r = 0;
 	r = handle->rcon_send(11, "list");
-	printf("[%d]: rcon_send: %d\n", handle->id, r);
+	printf("[%s]: rcon_send: %d\n", handle->id, r);
 	int id = -1;
 	char out[RCON_DATA_BUFFSIZE];
 	r = handle->rcon_recv(&id, out);
-	printf("[%d]: rcon_recv: %d. ID: %d, out: '%s'.\n", handle->id, r, id, out);
+	printf("[%s]: rcon_recv: %d. ID: %d, out: '%s'.\n", handle->id, r, id, out);
 	return 0;
 }
 
@@ -46,7 +47,7 @@ int epg_player_leave(struct epg_handle *handle,
 		char *player,
 		char *reason)
 {
-	printf("[%d]: %s left: %s.\n", handle->id, player, reason);
+	printf("[%s]: %s left: %s.\n", handle->id, player, reason);
 	return 0;
 }
 
@@ -54,7 +55,7 @@ int epg_player_say(struct epg_handle *handle,
 		char *player,
 		char *content)
 {
-	printf("[%d]: %s said: %s.\n", handle->id, player, content);
+	printf("[%s]: %s said: %s.\n", handle->id, player, content);
 	return 0;
 }
 
@@ -62,7 +63,7 @@ int epg_player_die(struct epg_handle *handle,
 		char *player,
 		char *source)
 {
-	printf("[%d]: %s died because of %s.\n", handle->id, player, source);
+	printf("[%s]: %s died because of %s.\n", handle->id, player, source);
 	return 0;
 }
 
@@ -70,7 +71,7 @@ int epg_player_achievement(struct epg_handle *handle,
 		char *player,
 		char *achievement)
 {
-	printf("[%d]: %s achieved %s.\n", handle->id, player, achievement);
+	printf("[%s]: %s achieved %s.\n", handle->id, player, achievement);
 	return 0;
 }
 
@@ -78,7 +79,7 @@ int epg_player_challenge(struct epg_handle *handle,
 		char *player,
 		char *challenge)
 {
-	printf("[%d]: %s made the challenge: %s.\n", handle->id, player, challenge);
+	printf("[%s]: %s made the challenge: %s.\n", handle->id, player, challenge);
 	return 0;
 }
 
@@ -86,26 +87,26 @@ int epg_player_goal(struct epg_handle *handle,
 		char *player,
 		char *goal)
 {
-	printf("[%d]: %s made the goal: %s.\n", handle->id, player, goal);
+	printf("[%s]: %s made the goal: %s.\n", handle->id, player, goal);
 	return 0;
 }
 
 int epg_server_stopping(struct epg_handle *handle)
 {
-	printf("[%d]: Server stopped.\n", handle->id);
+	printf("[%s]: Server stopped.\n", handle->id);
 	return 0;
 }
 
 int epg_server_starting(struct epg_handle *handle,
 		char *version)
 {
-	printf("[%d]: Server is starting, version: %s.\n", handle->id, version);
+	printf("[%s]: Server is starting, version: %s.\n", handle->id, version);
 	return 0;
 }
 
 int epg_server_started(struct epg_handle *handle,
 		char *took)
 {
-	printf("[%d]: Server started, took: %s.\n", handle->id, took);
+	printf("[%s]: Server started, took: %s.\n", handle->id, took);
 	return 0;
 }
-- 
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