MINOR: spoa-server: Add Lua processing

Use the defined binding for registering Lua engine.
diff --git a/contrib/spoa_server/Makefile b/contrib/spoa_server/Makefile
index e6b7c53..31e3de5 100644
--- a/contrib/spoa_server/Makefile
+++ b/contrib/spoa_server/Makefile
@@ -10,9 +10,19 @@
 
 OBJS = spoa.o
 
+ifneq ($(USE_LUA),)
+OBJS += ps_lua.o
+ifneq ($(LUA_INC),)
+CFLAGS += -I$(LUA_INC)
+endif
+ifneq ($(LUA_LIB),)
+LDLIBS += -L$(LUA_LIB)
+endif
+LDLIBS += -ldl -Wl,--export-dynamic -llua -lm -Wl,--no-export-dynamic
+endif
 
 spoa: $(OBJS)
-	$(LD) $(LDFLAGS) -o $@ $^
+	$(LD) $(LDFLAGS) -o $@ $^ $(LDLIBS)
 
 install: spoa
 	install spoa $(DESTDIR)$(BINDIR)
diff --git a/contrib/spoa_server/ps_lua.c b/contrib/spoa_server/ps_lua.c
new file mode 100644
index 0000000..e7de2d9
--- /dev/null
+++ b/contrib/spoa_server/ps_lua.c
@@ -0,0 +1,509 @@
+/* spoa-server: processing Lua
+ *
+ * Copyright 2018 OZON / Thierry Fournier <thierry.fournier@ozon.io>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <string.h>
+
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+
+#include "spoa.h"
+
+static lua_State *L = NULL;
+static struct worker *worker;
+
+static int ps_lua_start_worker(struct worker *w);
+static int ps_lua_load_file(struct worker *w, const char *file);
+static int ps_lua_exec_message(struct worker *w, void *ref, int nargs, struct spoe_kv *args);
+
+static struct ps ps_lua_bindings_1 = {
+	.init_worker = ps_lua_start_worker,
+	.load_file = ps_lua_load_file,
+	.exec_message = ps_lua_exec_message,
+	.ext = ".lua",
+};
+
+static struct ps ps_lua_bindings_2 = {
+	.init_worker = ps_lua_start_worker,
+	.load_file = ps_lua_load_file,
+	.exec_message = ps_lua_exec_message,
+	.ext = ".luac",
+};
+
+/* Imported from Lua-5.3.4 */
+static int typeerror (lua_State *L, int arg, const char *tname)
+{
+	const char *msg;
+	const char *typearg;  /* name for the type of the actual argument */
+	if (luaL_getmetafield(L, arg, "__name") == LUA_TSTRING)
+		typearg = lua_tostring(L, -1);  /* use the given type name */
+	else if (lua_type(L, arg) == LUA_TLIGHTUSERDATA)
+		typearg = "light userdata";  /* special name for messages */
+	else
+		typearg = luaL_typename(L, arg);  /* standard name */
+	msg = lua_pushfstring(L, "%s expected, got %s", tname, typearg);
+	return luaL_argerror(L, arg, msg);
+}
+
+/* Imported from Lua-5.3.4 */
+static void tag_error (lua_State *L, int arg, int tag) {
+	typeerror(L, arg, lua_typename(L, tag));
+}
+
+#ifndef luaL_checkboolean
+static int luaL_checkboolean(lua_State *L, int index)
+{
+	if (!lua_isboolean(L, index)) {
+		tag_error(L, index, LUA_TBOOLEAN);
+	}
+	return lua_toboolean(L, index);
+}
+#endif
+
+static int ps_lua_register_message(lua_State *L)
+{
+	const char *name;
+	long ref;
+
+	/* First argument is a message name */
+	name = luaL_checkstring(L, 1);
+
+	/* Second argument is a function */
+	if (!lua_isfunction(L, 2)) {
+		const char *msg = lua_pushfstring(L, "function expected, got %s", luaL_typename(L, 2));
+		luaL_argerror(L, 2, msg);
+	}
+	lua_pushvalue(L, 2);
+	ref = luaL_ref(L, LUA_REGISTRYINDEX);
+
+	/* Register the message processor */
+	ps_register_message(&ps_lua_bindings_1, name, (void *)ref);
+
+	return 1;
+}
+
+static int ps_lua_set_var_null(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+
+	if (!set_var_null(worker, name, name_len, scope)) {
+		luaL_error(L, "No space left available");
+	}
+	return 0;
+}
+
+static int ps_lua_set_var_boolean(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	int64_t value;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkboolean(L, 3);
+
+	if (!set_var_bool(worker, name, name_len, scope, value))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_uint32(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	int64_t value;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkinteger(L, 3);
+
+	if (value < 0 || value > UINT_MAX)
+		luaL_error(L, "Integer '%lld' out of range for 'uint32' type", value);
+
+	if (!set_var_uint32(worker, name, name_len, scope, value))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_int32(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	int64_t value;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkinteger(L, 3);
+
+	if (value < INT_MIN || value > INT_MAX)
+		luaL_error(L, "Integer '%lld' out of range for 'int32' type", value);
+
+	if (!set_var_int32(worker, name, name_len, scope, value))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_uint64(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	int64_t value;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkinteger(L, 3);
+
+	if (value < 0)
+		luaL_error(L, "Integer '%lld' out of range for 'uint64' type", value);
+
+	if (!set_var_uint64(worker, name, name_len, scope, value))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_int64(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	int64_t value;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkinteger(L, 3);
+
+	if (!set_var_int64(worker, name, name_len, scope, value))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_ipv4(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	const char *value;
+	struct in_addr ipv4;
+	int ret;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkstring(L, 3);
+
+	ret = inet_pton(AF_INET, value, &ipv4);
+	if (ret == 0)
+		luaL_error(L, "IPv4 '%s': invalid format", value);
+	if (ret == -1)
+		luaL_error(L, "IPv4 '%s': %s", value, strerror(errno));
+
+	if (!set_var_ipv4(worker, name, name_len, scope, &ipv4))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_ipv6(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	const char *value;
+	struct in6_addr ipv6;
+	int ret;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checkstring(L, 3);
+
+	ret = inet_pton(AF_INET6, value, &ipv6);
+	if (ret == 0)
+		luaL_error(L, "IPv6 '%s': invalid format", value);
+	if (ret == -1)
+		luaL_error(L, "IPv6 '%s': %s", value, strerror(errno));
+
+	if (!set_var_ipv6(worker, name, name_len, scope, &ipv6))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_str(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	const char *value;
+	size_t value_len;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checklstring(L, 3, &value_len);
+
+	if (!set_var_string(worker, name, name_len, scope, value, value_len))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_set_var_bin(lua_State *L)
+{
+	const char *name;
+	size_t name_len;
+	unsigned char scope;
+	const char *value;
+	size_t value_len;
+
+	name = luaL_checklstring(L, 1, &name_len);
+	scope = (unsigned char)luaL_checkinteger(L, 2);
+	value = luaL_checklstring(L, 3, &value_len);
+
+	if (!set_var_bin(worker, name, name_len, scope, value, value_len))
+		luaL_error(L, "No space left available");
+	return 0;
+}
+
+static int ps_lua_start_worker(struct worker *w)
+{
+	if (L != NULL)
+		return 1;
+
+	worker = w;
+
+	L = luaL_newstate();
+	luaL_openlibs(L);
+
+	lua_newtable(L);
+
+	lua_pushstring(L, "register_message");
+	lua_pushcclosure(L, ps_lua_register_message, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_null");
+	lua_pushcclosure(L, ps_lua_set_var_null, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_boolean");
+	lua_pushcclosure(L, ps_lua_set_var_boolean, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_uint32");
+	lua_pushcclosure(L, ps_lua_set_var_uint32, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_int32");
+	lua_pushcclosure(L, ps_lua_set_var_int32, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_uint64");
+	lua_pushcclosure(L, ps_lua_set_var_uint64, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_int64");
+	lua_pushcclosure(L, ps_lua_set_var_int64, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_ipv4");
+	lua_pushcclosure(L, ps_lua_set_var_ipv4, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_ipv6");
+	lua_pushcclosure(L, ps_lua_set_var_ipv6, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_str");
+	lua_pushcclosure(L, ps_lua_set_var_str, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "set_var_bin");
+	lua_pushcclosure(L, ps_lua_set_var_bin, 0);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "scope");
+	lua_newtable(L);
+
+	lua_pushstring(L, "proc");
+	lua_pushinteger(L, SPOE_SCOPE_PROC);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "sess");
+	lua_pushinteger(L, SPOE_SCOPE_SESS);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "txn");
+	lua_pushinteger(L, SPOE_SCOPE_TXN);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "req");
+	lua_pushinteger(L, SPOE_SCOPE_REQ);
+	lua_rawset(L, -3);
+
+	lua_pushstring(L, "res");
+	lua_pushinteger(L, SPOE_SCOPE_RES);
+	lua_rawset(L, -3);
+
+	lua_rawset(L, -3); /* scope */
+
+	lua_setglobal(L, "spoa");
+	return 1;
+}
+
+static int ps_lua_load_file(struct worker *w, const char *file)
+{
+	int error;
+
+	/* Load the file and check syntax */
+	error = luaL_loadfile(L, file);
+	if (error) {
+		fprintf(stderr, "lua syntax error: %s\n", lua_tostring(L, -1));
+		return 0;
+	}
+
+	/* If no syntax error where detected, execute the code. */
+	error = lua_pcall(L, 0, LUA_MULTRET, 0);
+   switch (error) {
+	case LUA_OK:
+		break;
+	case LUA_ERRRUN:
+		fprintf(stderr, "lua runtime error: %s\n", lua_tostring(L, -1));
+		lua_pop(L, 1);
+		return 0;
+	case LUA_ERRMEM:
+		fprintf(stderr, "lua out of memory error\n");
+		return 0;
+	case LUA_ERRERR:
+		fprintf(stderr, "lua message handler error: %s\n", lua_tostring(L, 0));
+		lua_pop(L, 1);
+		return 0;
+	case LUA_ERRGCMM:
+		fprintf(stderr, "lua garbage collector error: %s\n", lua_tostring(L, 0));
+		lua_pop(L, 1);
+		return 0;
+	default:
+		fprintf(stderr, "lua unknonwn error: %s\n", lua_tostring(L, 0));
+		lua_pop(L, 1);
+		return 0;
+	}
+	return 1;
+}
+
+static int ps_lua_exec_message(struct worker *w, void *ref, int nargs, struct spoe_kv *args)
+{
+	long lua_ref = (long)ref;
+	int ret;
+	char *msg_fmt = NULL;
+	const char *msg;
+	int i;
+	char ipbuf[64];
+
+	/* Restore function in the stack */
+	lua_rawgeti(L, LUA_REGISTRYINDEX, lua_ref);
+
+	/* convert args in lua mode */
+	lua_newtable(L);
+	for (i = 0; i < nargs; i++) {
+		lua_newtable(L);
+		lua_pushstring(L, "name");
+		lua_pushlstring(L, args[i].name.str, args[i].name.len);
+		lua_rawset(L, -3); /* Push name */
+		lua_pushstring(L, "value");
+		switch (args[i].value.type) {
+		case SPOE_DATA_T_NULL:
+			lua_pushnil(L);
+			break;
+		case SPOE_DATA_T_BOOL:
+			lua_pushboolean(L, args[i].value.u.boolean);
+			break;
+		case SPOE_DATA_T_INT32:
+			lua_pushinteger(L, args[i].value.u.sint32);
+			break;
+		case SPOE_DATA_T_UINT32:
+			lua_pushinteger(L, args[i].value.u.uint32);
+			break;
+		case SPOE_DATA_T_INT64:
+			lua_pushinteger(L, args[i].value.u.sint64);
+			break;
+		case SPOE_DATA_T_UINT64:
+			if (args[i].value.u.uint64 > LLONG_MAX)
+				lua_pushnil(L);
+			else
+				lua_pushinteger(L, args[i].value.u.uint64);
+			break;
+		case SPOE_DATA_T_IPV4:
+			if (inet_ntop(AF_INET, &args[i].value.u.ipv4, ipbuf, 64) == NULL)
+				lua_pushnil(L);
+			else
+				lua_pushstring(L, ipbuf);
+			break;
+		case SPOE_DATA_T_IPV6:
+			if (inet_ntop(AF_INET6, &args[i].value.u.ipv4, ipbuf, 64) == NULL)
+				lua_pushnil(L);
+			else
+				lua_pushstring(L, ipbuf);
+			break;
+		case SPOE_DATA_T_STR:
+		case SPOE_DATA_T_BIN:
+			lua_pushlstring(L, args[i].value.u.buffer.str, args[i].value.u.buffer.len);
+			break;
+		default:
+			lua_pushnil(L);
+			break;
+		}
+		lua_rawset(L, -3); /* Push name */
+		lua_rawseti(L, -2, i + 1); /* Pusg table in globale table */
+	}
+
+	/* execute lua function */
+	while (1) {
+		ret = lua_resume(L, L, 1);
+		switch (ret) {
+		case LUA_OK:
+			return 1;
+		case LUA_YIELD:
+			DEBUG("Lua yield");
+			continue;
+		case LUA_ERRMEM:
+			LOG("Lua: Out of memory error");
+			return 0;
+		case LUA_ERRRUN:
+			msg_fmt = "Lua runtime error";
+		case LUA_ERRGCMM:
+			msg_fmt = msg_fmt ? msg_fmt : "Lua garbage collector error";
+		case LUA_ERRERR:
+			msg_fmt = msg_fmt ? msg_fmt : "Lua message handler error";
+		default:
+			msg_fmt = msg_fmt ? msg_fmt : "Lua unknonwn error";
+			msg = lua_tostring(L, -1);
+			if (msg == NULL)
+				msg = "Unknown error";
+			LOG("%s: %s", msg_fmt, msg);
+			lua_settop(L, 0);
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+__attribute__((constructor))
+static void __ps_lua_init(void)
+{
+	ps_register(&ps_lua_bindings_1);
+	ps_register(&ps_lua_bindings_2);
+}