447 lines
11 KiB
C
447 lines
11 KiB
C
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/*
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* lua-loader.c: Lua plugin loader plugin
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*
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* Copyright (c) 2015, Přemysl Janouch <p.janouch@gmail.com>
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* All rights reserved.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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*/
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// I can't really recommend using this interface as it adds a lot of overhead
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#include "../utils.c"
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#include "../plugin-api.h"
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#include <dirent.h>
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#include <lua.h>
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#include <lualib.h>
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#include <lauxlib.h>
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// --- Utilities ---------------------------------------------------------------
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static struct plugin_data
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{
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void *ctx; ///< Application context
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struct plugin_api *api; ///< Plugin API vtable
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}
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g_data;
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static void *
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xlua_alloc (void *ud, void *ptr, size_t o_size, size_t n_size)
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{
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(void) ud;
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(void) o_size;
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if (n_size)
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return realloc (ptr, n_size);
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free (ptr);
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return NULL;
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}
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static int
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xlua_panic (lua_State *L)
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{
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// XXX: we might be able to do something better
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print_fatal ("Lua panicked: %s", lua_tostring (L, -1));
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lua_close (L);
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exit (EXIT_FAILURE);
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return 0;
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}
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// --- Unit wrapper ------------------------------------------------------------
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struct unit_wrapper
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{
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struct unit *unit; ///< The underlying unit
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};
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#define UNIT_METATABLE "unit"
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static int
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xlua_unit_get_address (lua_State *L)
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{
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struct unit_wrapper *data = luaL_checkudata (L, 1, UNIT_METATABLE);
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lua_pushstring (L, g_data.api->unit_get_address (data->unit));
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return 1;
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}
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static int
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xlua_unit_write (lua_State *L)
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{
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struct unit_wrapper *data = luaL_checkudata (L, 1, UNIT_METATABLE);
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size_t buffer_len;
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const char *buffer = luaL_checklstring (L, 2, &buffer_len);
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lua_pushinteger (L, g_data.api->unit_write
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(data->unit, buffer, buffer_len));
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return 1;
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}
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static int
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xlua_unit_set_success (lua_State *L)
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{
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struct unit_wrapper *data = luaL_checkudata (L, 1, UNIT_METATABLE);
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bool success = lua_toboolean (L, 2);
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g_data.api->unit_set_success (data->unit, success);
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return 0;
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}
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static int
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xlua_unit_add_info (lua_State *L)
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{
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struct unit_wrapper *data = luaL_checkudata (L, 1, UNIT_METATABLE);
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const char *info = luaL_checkstring (L, 2);
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g_data.api->unit_add_info (data->unit, info);
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return 0;
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}
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static int
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xlua_unit_abort (lua_State *L)
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{
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struct unit_wrapper *data = luaL_checkudata (L, 1, UNIT_METATABLE);
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g_data.api->unit_abort (data->unit);
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return 0;
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}
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static int
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xlua_unit_destroy (lua_State *L)
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{
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// TODO: when creating the wrapper object, increase the reference
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// count for the unit and decrease it in here again. If we don't do
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// this, the Lua plugin may cause a use-after-free error.
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(void) L;
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return 0;
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}
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static luaL_Reg xlua_unit_table[] =
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{
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{ "get_address", xlua_unit_get_address },
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{ "write", xlua_unit_write },
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{ "set_success", xlua_unit_set_success },
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{ "add_info", xlua_unit_add_info },
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{ "abort", xlua_unit_abort },
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{ "__gc", xlua_unit_destroy },
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{ NULL, NULL }
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};
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// --- Scan wrapper ------------------------------------------------------------
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struct service_data
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{
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struct service *service; ///< The corresponding service
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lua_State *L; ///< Lua state
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int new_scan_cb_ref; ///< Reference to "new_scan" callback
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};
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struct scan_data
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{
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struct service *service; ///< The corresponding service
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struct unit *unit; ///< The corresponding unit
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lua_State *L; ///< Lua state
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int scan_ref; ///< Reference to scan data in Lua
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};
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static void *
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scan_init (struct service *self, struct unit *unit)
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{
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struct service_data *service = self->user_data;
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lua_geti (service->L, LUA_REGISTRYINDEX, service->new_scan_cb_ref);
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// Wrap the unit in Lua userdata so that Lua code can use it
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struct unit_wrapper *wrapper =
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lua_newuserdata (service->L, sizeof *wrapper);
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wrapper->unit = unit;
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luaL_setmetatable (service->L, UNIT_METATABLE);
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// Ask for a Lua object (table) to use for protocol detection
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if (lua_pcall (service->L, 1, 1, 0))
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{
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print_error ("Lua: service `%s': new_scan: %s",
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service->service->name, lua_tostring (service->L, -1));
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lua_pop (service->L, 1);
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return NULL;
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}
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if (!lua_istable (service->L, -1))
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{
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print_error ("Lua: service `%s': new_scan must return a table",
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service->service->name);
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return NULL;
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}
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// Return a scan handle
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struct scan_data *data = xmalloc (sizeof *data);
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data->service = self;
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data->L = service->L;
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data->scan_ref = luaL_ref (service->L, LUA_REGISTRYINDEX);
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data->unit = unit;
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return data;
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}
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static void
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scan_free (void *handle)
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{
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if (!handle)
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return;
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struct scan_data *data = handle;
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luaL_unref (data->L, LUA_REGISTRYINDEX, data->scan_ref);
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free (handle);
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}
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static void
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handle_scan_method_failure (struct scan_data *data)
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{
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print_error ("Lua: service `%s': %s", data->service->name,
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lua_tostring (data->L, -1));
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g_data.api->unit_abort (data->unit);
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lua_pop (data->L, 1);
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}
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static bool
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prepare_scan_method (struct scan_data *data, const char *method_name)
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{
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if (!data)
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return false;
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lua_geti (data->L, LUA_REGISTRYINDEX, data->scan_ref);
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lua_getfield (data->L, -1, method_name);
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if (lua_isnil (data->L, -1))
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{
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lua_pop (data->L, 2);
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return false;
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}
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if (!lua_isfunction (data->L, -1))
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{
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lua_pop (data->L, 2);
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lua_pushfstring (data->L, "`%s' must be a function", method_name);
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handle_scan_method_failure (data);
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return false;
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}
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// Swap the first two values on the stack, so that the function
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// is first and the object we're calling it on is second
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lua_insert (data->L, -2);
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return true;
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}
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static void
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on_data (void *handle, const void *network_data, size_t len)
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{
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struct scan_data *data = handle;
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if (!prepare_scan_method (data, "on_data"))
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return;
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lua_pushlstring (data->L, network_data, len);
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if (lua_pcall (data->L, 2, 0, 0))
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handle_scan_method_failure (data);
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}
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static void
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on_eof (void *handle)
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{
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struct scan_data *data = handle;
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if (!prepare_scan_method (data, "on_eof"))
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return;
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if (lua_pcall (data->L, 1, 0, 0))
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handle_scan_method_failure (data);
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}
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static void
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on_error (void *handle)
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{
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struct scan_data *data = handle;
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if (!prepare_scan_method (data, "on_error"))
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return;
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if (lua_pcall (data->L, 1, 0, 0))
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handle_scan_method_failure (data);
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}
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static void
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on_aborted (void *handle)
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{
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struct scan_data *data = handle;
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if (!prepare_scan_method (data, "on_aborted"))
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return;
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if (lua_pcall (data->L, 1, 0, 0))
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handle_scan_method_failure (data);
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}
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// --- Top-level interface -----------------------------------------------------
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static int
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xlua_register_service (lua_State *L)
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{
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// Validate and decode the arguments
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luaL_checktype (L, 1, LUA_TTABLE);
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lua_getfield (L, 1, "name");
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if (!lua_isstring (L, -1))
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return luaL_error (L, "service registration failed: "
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"invalid or missing `%s'", "name");
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const char *name = lua_tostring (L, -1);
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lua_pop (L, 1);
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lua_getfield (L, 1, "flags");
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lua_Unsigned flags;
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if (lua_isnil (L, -1))
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flags = 0;
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else if (lua_isinteger (L, -1))
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flags = lua_tointeger (L, -1);
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else
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return luaL_error (L, "service registration failed: "
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"invalid or missing `%s'", "flags");
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lua_pop (L, 1);
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lua_getfield (L, 1, "new_scan");
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if (!lua_isfunction (L, -1))
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return luaL_error (L, "service registration failed: "
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"invalid or missing `%s'", "new_scan");
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// Reference the "new_scan" function for later use
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struct service_data *data = xcalloc (1, sizeof *data);
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data->L = L;
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data->new_scan_cb_ref = luaL_ref (L, LUA_REGISTRYINDEX);
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// Register a new service that proxies calls to Lua code
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struct service *s = data->service = xcalloc (1, sizeof *s);
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s->name = xstrdup (name);
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s->flags = flags;
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s->user_data = data;
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s->scan_init = scan_init;
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s->scan_free = scan_free;
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s->on_data = on_data;
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s->on_eof = on_eof;
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s->on_error = on_error;
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s->on_aborted = on_aborted;
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g_data.api->register_service (g_data.ctx, s);
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return 0;
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}
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static int
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xlua_get_config (lua_State *L)
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{
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const char *key = luaL_checkstring (L, 1);
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lua_pushstring (L, g_data.api->get_config (g_data.ctx, key));
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return 0;
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}
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static luaL_Reg xlua_library[] =
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{
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{ "register_service", xlua_register_service },
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{ "get_config", xlua_get_config },
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{ NULL, NULL }
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};
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static bool
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load_one_plugin (lua_State *L, const char *name, const char *path)
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{
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int ret;
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if (!(ret = luaL_loadfile (L, path))
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&& !(ret = lua_pcall (L, 0, 0, 0)))
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return true;
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print_error ("Lua: could not load `%s': %s", name, lua_tostring (L, -1));
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lua_pop (L, 1);
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return false;
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}
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static bool
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initialize (void *ctx, struct plugin_api *api)
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{
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g_data = (struct plugin_data) { .ctx = ctx, .api = api };
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if (sizeof (lua_Integer) < 8)
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{
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print_error ("%s: %s", "Lua",
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"at least 64-bit Lua integers are required");
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return false;
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}
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const char *plugin_dir = api->get_config (ctx, "plugin_dir");
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if (!plugin_dir)
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{
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print_fatal ("%s: %s", "Lua", "no plugin directory defined");
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return false;
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}
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DIR *dir = opendir (plugin_dir);
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if (!dir)
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{
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print_fatal ("%s: %s: %s", "Lua",
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"cannot open plugin directory", strerror (errno));
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return false;
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}
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bool success = false;
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lua_State *L;
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if (!(L = lua_newstate (xlua_alloc, NULL)))
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{
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print_fatal ("%s: %s", "Lua", "initialization failed");
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goto end;
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}
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lua_atpanic (L, xlua_panic);
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luaL_openlibs (L);
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// Register the ponymap library
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luaL_newlib (L, xlua_library);
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lua_pushinteger (L, SERVICE_SUPPORTS_TLS);
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lua_setfield (L, -2, "SERVICE_SUPPORTS_TLS");
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lua_setglobal (L, PROGRAM_NAME);
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// Create a metatable for the units
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luaL_newmetatable (L, UNIT_METATABLE);
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lua_pushvalue (L, -1);
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lua_setfield (L, -2, "__index");
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luaL_setfuncs (L, xlua_unit_table, 0);
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struct dirent buf, *iter;
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while (true)
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{
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if (readdir_r (dir, &buf, &iter))
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{
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print_fatal ("%s: %s: %s", "Lua", "readdir_r", strerror (errno));
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break;
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}
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if (!iter)
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{
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success = true;
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break;
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}
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char *dot = strrchr (iter->d_name, '.');
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if (!dot || strcmp (dot, ".lua"))
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continue;
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char *path = xstrdup_printf ("%s/%s", plugin_dir, iter->d_name);
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(void) load_one_plugin (L, iter->d_name, path);
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free (path);
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}
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end:
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closedir (dir);
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return success;
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}
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struct plugin_info ponymap_plugin_info =
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{
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.api_version = API_VERSION,
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.initialize = initialize
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};
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