root/src/common/plugins.c @ 1

// Copyright (c) Athena Dev Teams - Licensed under GNU GPL
// For more information, see LICENCE in the main folder

#include "../common/mmo.h"
#include "../common/core.h"
#include "../common/timer.h"
#include "../common/utils.h" // findfile()
#include "../common/socket.h"
#include "../common/malloc.h"
#include "../common/version.h"
#include "../common/showmsg.h"
#include "plugins.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef WIN32
#include <unistd.h>
#endif

//////////////////////////////////////////////

typedef struct _Plugin_Event {
        struct _Plugin_Event* next;
        Plugin_Event_Func* func;
} Plugin_Event;

typedef struct _Plugin_Event_List {
        struct _Plugin_Event_List* next;
        char* name;
        struct _Plugin_Event* events;
} Plugin_Event_List;

static int auto_search = 0;
static int load_priority = 0;
Plugin_Event_List* event_head = NULL;
Plugin* plugin_head = NULL;

static Plugin_Info default_info = { "Unknown", PLUGIN_ALL, "0", PLUGIN_VERSION, "Unknown" };

void** plugin_call_table;
static size_t call_table_size   = 0;
static size_t max_call_table    = 0;

////// Plugin Events Functions //////////////////

int register_plugin_func(char* name)
{
        Plugin_Event_List* evl;
        if( name ){
                //ShowDebug("register_plugin_func(%s)\n", name);
                CREATE(evl, Plugin_Event_List, 1);
                evl->next = event_head;
                evl->name = aStrdup(name);
                evl->events = NULL;
                event_head = evl;
        }
        return 0;
}

static Plugin_Event_List* search_plugin_func(char* name)
{
        Plugin_Event_List* evl = event_head;
        while( evl ){
                if( strcmpi(evl->name,name) == 0 )
                        return evl;
                evl = evl->next;
        }
        return NULL;
}

int register_plugin_event(Plugin_Event_Func* func, char* name)
{
        Plugin_Event_List* evl = search_plugin_func(name);
        //ShowDebug("register_plugin_event(0x%x, %s)\n", func, name);
        if( !evl )
        {// event does not exist, register
                register_plugin_func(name);
                // get the new event list
                evl = search_plugin_func(name);
        }
        if( evl ){
                Plugin_Event* ev;

                CREATE(ev, Plugin_Event, 1);
                ev->func = func;
                ev->next = NULL;

                // insert event at the end of the linked list
                if( evl->events == NULL )
                        evl->events = ev;
                else {
                        Plugin_Event* last_ev = evl->events;
                        while( last_ev ){
                                if( last_ev->next == NULL ){
                                        last_ev->next = ev;
                                        break;
                                }
                                last_ev = last_ev->next;
                        }
                }
        }
        return 0;
}

int plugin_event_trigger(char* name)
{
        int c = 0;
        Plugin_Event_List* evl = search_plugin_func(name);
        //ShowDebug("plugin_event_trigger(%s)\n", name);
        if( evl ){
                Plugin_Event* ev = evl->events;
                while( ev ){
                        ev->func();
                        //ShowDebug("plugin_event_trigger: Executing function 0x%x.\n", ev->func);
                        ev = ev->next;
                        ++c;
                }
        }
        return c;
}

////// Plugins Call Table Functions /////////

int export_symbol(void* var, size_t offset)
{
        //ShowDebug("export_symbol(0x%x,%d)\n", var,offset);

        // add to the end of the list
        if( offset < 0 )
                offset = call_table_size;

        if( offset >= max_call_table )
        {// realloc if not large enough  
                max_call_table = 1 + offset;
                RECREATE(plugin_call_table, void*, max_call_table);

                // clear the new alloced block
                memset(plugin_call_table + call_table_size, 0, (max_call_table-call_table_size)*sizeof(void*));
        }

        // the new table size is delimited by the new element at the end
        if( offset >= call_table_size )
                call_table_size = offset+1;

        // put the pointer at the selected place
        plugin_call_table[offset] = var;
        return 0;
}

////// Plugins Core /////////////////////////

static int plugin_iscompatible(char* version)
{
        int req_major = 0;
        int req_minor = 0;
        int major = 0;
        int minor = 0;

        if( version == NULL )
                return 0;
        sscanf(version, "%d.%d", &req_major, &req_minor);
        sscanf(version, "%d.%d", &major, &minor);
        return ( req_major == major || req_minor <= minor );
}

Plugin* plugin_open(const char* filename)
{
        Plugin* plugin;
        Plugin_Info* info;
        Plugin_Event_Table* events;
        void** procs;
        int init_flag = 1;

        //ShowDebug("plugin_open(%s)\n", filename);
        
        // Check if the plugin has been loaded before
        plugin = plugin_head;
        while (plugin) {
                // returns handle to the already loaded plugin
                if( plugin->state && strcmpi(plugin->filename, filename) == 0 ){
                        ShowWarning("plugin_open: not loaded (duplicate) : '"CL_WHITE"%s"CL_RESET"'\n", filename);
                        return plugin;
                }
                plugin = plugin->next;
        }

        CREATE(plugin, Plugin, 1);
        plugin->state = -1;     // not loaded

        plugin->dll = DLL_OPEN(filename);
        if( !plugin->dll ){
                ShowWarning("plugin_open: not loaded (invalid file) : '"CL_WHITE"%s"CL_RESET"'\n", filename);
                plugin_unload(plugin);
                return NULL;
        }

        // Retrieve plugin information
        plugin->state = 0;      // initialising
        info = (Plugin_Info*)DLL_SYM(plugin->dll, "plugin_info");
        // For high priority plugins (those that are explicitly loaded from the conf file)
        // we'll ignore them even (could be a 3rd party dll file)
        if( !info )
        {// foreign plugin
                //ShowDebug("plugin_open: plugin_info not found\n");
                if( load_priority == 0 )
                {// not requested
                        //ShowDebug("plugin_open: not loaded (not requested) : '"CL_WHITE"%s"CL_RESET"'\n", filename);
                        plugin_unload(plugin);
                        return NULL;
                }
        } else if( !plugin_iscompatible(info->req_version) )
        {// incompatible version
                ShowWarning("plugin_open: not loaded (incompatible version '%s' -> '%s') : '"CL_WHITE"%s"CL_RESET"'\n", info->req_version, PLUGIN_VERSION, filename);
                plugin_unload(plugin);
                return NULL;
        } else if( (info->type != PLUGIN_ALL && info->type != PLUGIN_CORE && info->type != SERVER_TYPE) ||
                (info->type == PLUGIN_CORE && SERVER_TYPE != PLUGIN_LOGIN && SERVER_TYPE != PLUGIN_CHAR && SERVER_TYPE != PLUGIN_MAP) )
        {// not for this server
                //ShowDebug("plugin_open: not loaded (incompatible) : '"CL_WHITE"%s"CL_RESET"'\n", filename);
                plugin_unload(plugin);
                return NULL;
        }

        plugin->info = ( info != NULL ? info : &default_info );
        plugin->filename = aStrdup(filename);

        // Initialise plugin call table (For exporting procedures)
        procs = (void**)DLL_SYM(plugin->dll, "plugin_call_table");
        if( procs )
                *procs = plugin_call_table;
        //else ShowDebug("plugin_open: plugin_call_table not found\n");

        // Register plugin events
        events = (Plugin_Event_Table*)DLL_SYM(plugin->dll, "plugin_event_table");
        if( events ){
                int i = 0;
                //ShowDebug("plugin_open: parsing plugin_event_table\n");
                while( events[i].func_name ){
                        if( strcmpi(events[i].event_name, EVENT_PLUGIN_TEST) == 0 ){
                                Plugin_Test_Func* test_func;
                                test_func = (Plugin_Test_Func*)DLL_SYM(plugin->dll, events[i].func_name);
                                //ShowDebug("plugin_open: invoking "EVENT_PLUGIN_TEST" with %s()\n", events[i].func_name);
                                if( test_func && test_func() == 0 ){
                                        // plugin has failed test, disabling
                                        //ShowDebug("plugin_open: disabled (failed test) : %s\n", filename);
                                        init_flag = 0;
                                }
                        } else {
                                Plugin_Event_Func* func;
                                func = (Plugin_Event_Func*)DLL_SYM(plugin->dll, events[i].func_name);
                                if (func)
                                        register_plugin_event(func, events[i].event_name);
                        }
                        i++;
                }
        }
        //else ShowDebug("plugin_open: plugin_event_table not found\n");

        plugin->next = plugin_head;
        plugin_head = plugin;

        plugin->state = init_flag;      // fully loaded
        ShowStatus("Done loading plugin '"CL_WHITE"%s"CL_RESET"'\n", (info) ? plugin->info->name : filename);

        return plugin;
}

void plugin_load(const char* filename)
{
        plugin_open(filename);
}

void plugin_unload(Plugin* plugin)
{
        if( plugin == NULL )
                return;
        if( plugin->filename )
                aFree(plugin->filename);
        if( plugin->dll )
                DLL_CLOSE(plugin->dll);
        aFree(plugin);
}

#ifdef WIN32
char *DLL_ERROR(void)
{
        static char dllbuf[80];
        DWORD dw = GetLastError();
        FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, dw, 0, dllbuf, 80, NULL);
        return dllbuf;
}
#endif

////// Initialize/Finalize ////////////////////

static int plugins_config_read(const char *cfgName)
{
        char line[1024], w1[1024], w2[1024];
        FILE *fp;

        fp = fopen(cfgName, "r");
        if( fp == NULL ){
                ShowError("File not found: %s\n", cfgName);
                return 1;
        }
        while( fgets(line, sizeof(line), fp) )
        {
                if( line[0] == '/' && line[1] == '/' )
                        continue;
                if( sscanf(line,"%[^:]: %[^\r\n]",w1,w2) != 2 )
                        continue;

                if( strcmpi(w1,"auto_search") == 0 ){
                        if( strcmpi(w2,"yes") == 0 )
                                auto_search = 1;
                        else if( strcmpi(w2,"no") == 0 )
                                auto_search = 0;
                        else
                                auto_search = atoi(w2);
                } else if( strcmpi(w1,"plugin") == 0 ){
                        char filename[128];
                        sprintf(filename, "plugins/%s%s", w2, DLL_EXT);
                        plugin_load(filename);
                } else if( strcmpi(w1,"import") == 0 )
                        plugins_config_read(w2);
        }
        fclose(fp);
        return 0;
}

void plugins_init(void)
{
        // Sugested functionality:
        // add atcommands/script commands (Borf)
        char* PLUGIN_CONF_FILENAME = "conf/plugin_athena.conf";
        //ShowDebug("plugins_init()\n");
        register_plugin_func(EVENT_PLUGIN_INIT);
        register_plugin_func(EVENT_PLUGIN_FINAL);
        register_plugin_func(EVENT_ATHENA_INIT);
        register_plugin_func(EVENT_ATHENA_FINAL);

        // networking
        EXPORT_SYMBOL(RFIFOSKIP,  SYMBOL_RFIFOSKIP);
        EXPORT_SYMBOL(WFIFOSET,   SYMBOL_WFIFOSET);
        EXPORT_SYMBOL(do_close,   SYMBOL_DELETE_SESSION);
        EXPORT_SYMBOL(session,    SYMBOL_SESSION);
        EXPORT_SYMBOL(&fd_max,    SYMBOL_FD_MAX);
        EXPORT_SYMBOL(addr_,      SYMBOL_ADDR);
        // timers
        EXPORT_SYMBOL(get_uptime,              SYMBOL_GET_UPTIME);
        EXPORT_SYMBOL(delete_timer,            SYMBOL_DELETE_TIMER);
        EXPORT_SYMBOL(add_timer_func_list,     SYMBOL_ADD_TIMER_FUNC_LIST);
        EXPORT_SYMBOL(add_timer_interval,      SYMBOL_ADD_TIMER_INTERVAL);
        EXPORT_SYMBOL(add_timer,               SYMBOL_ADD_TIMER);
        EXPORT_SYMBOL((void*)get_svn_revision, SYMBOL_GET_SVN_REVISION);
        EXPORT_SYMBOL(gettick,                 SYMBOL_GETTICK);
        // core
        EXPORT_SYMBOL(parse_console, SYMBOL_PARSE_CONSOLE);
        EXPORT_SYMBOL(&runflag,      SYMBOL_RUNFLAG);
        EXPORT_SYMBOL(arg_v,         SYMBOL_ARG_V);
        EXPORT_SYMBOL(&arg_c,        SYMBOL_ARG_C);
        EXPORT_SYMBOL(SERVER_NAME,   SYMBOL_SERVER_NAME);
        EXPORT_SYMBOL(&SERVER_TYPE,  SYMBOL_SERVER_TYPE);

        load_priority = 1;
        plugins_config_read(PLUGIN_CONF_FILENAME);
        load_priority = 0;

        if( auto_search )
                findfile("plugins", DLL_EXT, plugin_load);

        plugin_event_trigger(EVENT_PLUGIN_INIT);

        return;
}

void plugins_final(void)
{
        Plugin* plugin = plugin_head;
        Plugin* next_plugin;
        Plugin_Event_List* evl = event_head;
        Plugin_Event_List* next_evl;
        Plugin_Event* ev;
        Plugin_Event* next_ev;

        //ShowDebug("plugins_final()\n");
        plugin_event_trigger(EVENT_PLUGIN_FINAL);

        while( plugin ){
                next_plugin = plugin->next;
                plugin_unload(plugin);
                plugin = next_plugin;
        }

        while( evl ){
                ev = evl->events;
                while( ev ){
                        next_ev = ev->next;
                        aFree(ev);
                        ev = next_ev;
                }
                next_evl = evl->next;
                aFree(evl->name);
                aFree(evl);
                evl = next_evl;
        }

        aFree(plugin_call_table);

        return;
}