Implementation of put state function

MatheusNtg · MatheusNtg · commit e9663d312735 · 2020-10-30T18:13:45.000Z
diff --git a/Makefile b/Makefile
@@ -1,4 +1,4 @@
-ccflags-y += -D_LUNATIK -D_KERNEL -I$(src) -D_CONFIG_FULL_PANIC -DLUNATIK_UNUSED \
+ccflags-y += -D_LUNATIK -D_KERNEL -I$(src) -D_CONFIG_FULL_PANIC -DLUNATIK_UNUSED -DDEBUG\
 	-I$(src)/lua -I$(src)/deps/lua-memory/src
 asflags-y += -D_LUNATIK -D_KERNEL
 
diff --git a/lib/lunatik.c b/lib/lunatik.c
@@ -546,6 +546,9 @@ static int response_state_handler(struct nl_msg *msg, void *arg)
 	} else if (attrs_tb[OP_ERROR] && nla_get_u8(attrs_tb[OP_ERROR])) {
 		state->cb_result = CB_ERROR;
 		return NL_OK;
+	} else if (attrs_tb[NOT_IN_USE] && nla_get_u8(attrs_tb[NOT_IN_USE])) {
+		state->cb_result = CB_ERROR;
+		return NL_OK;
 	}
 
 	if (attrs_tb[CURR_ALLOC]) {
@@ -810,3 +813,24 @@ int lunatik_getcurralloc(struct lunatik_nl_state *state)
 	printf("Failed to put attribute to get current alloc of state %s\n", state->name);
 	return -1;
 }
+
+int lunatik_putstate(struct lunatik_nl_state *state)
+{
+	struct nl_msg *msg;
+	
+	int err = -1;
+
+	if ((msg = prepare_message(PUT_STATE, 0)) == NULL) 
+		return err;
+
+	NLA_PUT_STRING(msg, STATE_NAME, state->name);
+
+	if ((err = nl_send_auto(state->control_sock, msg)) < 0)
+		return err;	
+
+	return receive_state_op_result(state);
+
+nla_put_failure:
+	printf("Failed to put attribute to put state\n");
+	return -1;
+}
diff --git a/lib/lunatik.h b/lib/lunatik.h
@@ -22,6 +22,7 @@
 
 #include <sys/user.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <netlink/genl/genl.h>
 #include "../netlink_common.h"
 #include "../lunatik_conf.h"
@@ -53,6 +54,7 @@ struct lunatik_nl_state {
 	enum callback_result cb_result;
 	uint32_t maxalloc;
 	uint32_t curralloc;
+	bool isvalid;
 	char name[LUNATIK_NAME_MAXSIZE];
 };
 
@@ -113,4 +115,6 @@ int lunatik_datasend(struct lunatik_nl_state *state,
 
 int lunatik_getcurralloc(struct lunatik_nl_state *state);
 
+int lunatik_putstate(struct lunatik_nl_state *state);
+
 #endif /* LUNATIK_H */
diff --git a/lib/lunatik_module.c b/lib/lunatik_module.c
@@ -135,6 +135,8 @@ static int lsession_newstate(lua_State *L)
 	strcpy(state->name, name);
 	state->maxalloc = maxalloc;
 	state->session = session;
+	state->isvalid = true;
+
 
 	if (lunatikS_newstate(session, state)) {
 		pusherrmsg(L, "Failed to create the state\n");
@@ -154,6 +156,10 @@ static int lsession_newstate(lua_State *L)
 static int lstate_close(lua_State *L)
 {
 	struct lunatik_nl_state *state = getnlstate(L);
+
+	if (!state->isvalid)
+		return luaL_error(L, "invalid state");
+
 	if (lunatik_closestate(state)){
 		lua_pushnil(L);
 		return 1;
@@ -170,10 +176,12 @@ static int lstate_dostring(lua_State *L)
 	const char *payload = luaL_checklstring(L, 2, &len);
 	const char *script_name = luaL_optstring(L, 3, "Lunatik");
 
-	if (strlen(script_name) > LUNATIK_SCRIPTNAME_MAXSIZE) {
-		printf("script name too long\n");
-		goto error;
-	}
+	if (strlen(script_name) > LUNATIK_SCRIPTNAME_MAXSIZE)
+		return luaL_argerror(L, 3, "script name too long");
+
+	if (!s->isvalid)
+		return luaL_error(L, "invalid state");
+
 	int status = lunatik_dostring(s, payload, script_name, len);
 
 	if (status)
@@ -189,12 +197,20 @@ static int lstate_dostring(lua_State *L)
 
 static int lstate_getname(lua_State *L) {
 	struct lunatik_nl_state *s = getnlstate(L);
+
+	if (!s->isvalid)
+		return luaL_error(L, "invalid state");
+
 	lua_pushstring(L, s->name);
 	return 1;
 }
 
 static int lstate_getmaxalloc(lua_State *L) {
 	struct lunatik_nl_state *s = getnlstate(L);
+
+	if (!s->isvalid)
+		return luaL_error(L, "invalid state");
+
 	lua_pushinteger(L, s->maxalloc);
 	return 1;
 }
@@ -240,6 +256,7 @@ static int lsession_getstate(lua_State *L)
 	}
 
 	*state = *received_state;
+	state->isvalid = true;
 
 	if (lunatik_initstate(state)) {
 		pusherrmsg(L, "Failed to initialize the state\n");
@@ -277,6 +294,10 @@ static int lstate_datasend(lua_State *L)
 
 	if (buffer == NULL) luaL_argerror(L, 2, "expected non NULL memory object");
 
+	if (!state->isvalid)
+		return luaL_error(L, "invalid state");
+
+
 	err = lunatik_datasend(state, buffer, size);
 	err ? lua_pushnil(L) : lua_pushboolean(L, true);
 
@@ -290,6 +311,9 @@ static int lstate_datareceive(lua_State *L)
 	struct lunatik_nl_state *state = getnlstate(L);
 	char *memory;
 
+	if (!state->isvalid)
+		return luaL_error(L, "invalid state");
+
 	if (lunatik_receive(state))
 		goto error;
 
@@ -309,6 +333,9 @@ static int lstate_getcurralloc(lua_State *L)
 {
 	struct lunatik_nl_state *state = getnlstate(L);
 
+	if (!state->isvalid)
+		return luaL_error(L, "invalid state");
+
 	if (lunatik_getcurralloc(state)) {
 		lua_pushnil(L);
 		return 1;
@@ -319,6 +346,21 @@ static int lstate_getcurralloc(lua_State *L)
 	return 1;
 }
 
+static int lstate_put(lua_State *L)
+{
+	struct lunatik_nl_state *state = getnlstate(L);
+
+	if (lunatik_putstate(state)) {
+		lua_pushnil(L);
+		return 1;
+	}
+
+	lua_pushboolean(L, true);
+	state->isvalid = false;
+
+	return 1;
+}
+
 static const luaL_Reg session_mt[] = {
 	{"close", lsession_close},
 	{"getfd", lsession_getfd},
@@ -337,6 +379,7 @@ static const luaL_Reg state_mt[] = {
 	{"close", lstate_close},
 	{"send", lstate_datasend},
 	{"receive", lstate_datareceive},
+	{"put", lstate_put},
 	{NULL, NULL}
 };
 
diff --git a/lib/tests/send.lua b/lib/tests/send.lua
@@ -5,7 +5,9 @@ local session = lunatik.session()
 local buffer = memory.create(3)
 memory.set(buffer, 1, 0x1, 0x2, 0x3)
 
+-- TODO the kscript variable starts with \n, if such variable starts with \t then a kernel panic along with a deadlock will occour
 local kscript = [[
+
 	function receive_callback(mem)
 		print'A memory has been received'
 		memory.tostring(mem)
diff --git a/lunatik.h b/lunatik.h
@@ -56,7 +56,7 @@ int lunatik_close(const char *name);
 lunatik_State *lunatik_statelookup(const char *name);
 
 bool lunatik_getstate(lunatik_State *s);
-void lunatik_putstate(lunatik_State *s);
+int lunatik_putstate(lunatik_State *s);
 
 lunatik_State *lunatik_netnewstate(const char *name, size_t maxalloc, struct net *net);
 int lunatik_netclosestate(const char *name, struct net *net);
diff --git a/netlink.c b/netlink.c
@@ -51,6 +51,7 @@ static int lunatikN_data(struct sk_buff *buff, struct genl_info *info);
 static int lunatikN_datainit(struct sk_buff *buff, struct genl_info *info);
 static int lunatikN_sendstate(struct sk_buff *buff, struct genl_info *info);
 static int lunatikN_getcurralloc(struct sk_buff *buff, struct genl_info *info);
+static int lunatikN_putstate(struct sk_buff *buff, struct genl_info *info);
 
 struct nla_policy lunatik_policy[ATTRS_COUNT] = {
 	[STATE_NAME]  = { .type = NLA_STRING },
@@ -123,8 +124,16 @@ static const struct genl_ops l_ops[] = {
 		.doit   = lunatikN_getcurralloc,
 #if LINUX_VERSION_CODE < KERNEL_VERSION(5,2,0)
 		.policy = lunatik_policy
+#endif
+	},
+	{
+		.cmd    = PUT_STATE,
+		.doit   = lunatikN_putstate,
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,2,0)
+		.policy = lunatik_policy
 #endif
 	}
+
 };
 
 struct genl_family lunatik_family = {
@@ -714,6 +723,38 @@ static int lunatikN_getcurralloc(struct sk_buff *buff, struct genl_info *info)
 	return 0;
 }
 
+static int lunatikN_putstate(struct sk_buff *buff, struct genl_info *info)
+{
+	struct lunatik_state *s;
+	char *state_name;
+
+	pr_debug("Received a PUT_STATE command\n");
+
+	state_name = (char*)nla_data(info->attrs[STATE_NAME]);
+	s = lunatik_netstatelookup(state_name, genl_info_net(info));
+
+	if (s == NULL)
+		goto error;
+
+	if (!s->inuse) {
+		reply_with(NOT_IN_USE, PUT_STATE, info);
+		return 0;
+	}
+
+	if (lunatik_putstate(s))
+		goto error;
+
+
+	s->inuse = false;
+	reply_with(OP_SUCESS, PUT_STATE, info);
+
+	return 0;
+
+error:
+	reply_with(OP_ERROR, PUT_STATE, info);
+	return 0;
+}
+
 /* Note: Most of the function below is copied from NFLua: https://github.com/cujoai/nflua
  * Copyright (C) 2017-2019  CUJO LLC
  *
diff --git a/netlink_common.h b/netlink_common.h
@@ -44,6 +44,7 @@ enum lunatik_operations {
 	DATA_INIT,
 	GET_STATE,
 	GET_CURRALLOC,
+	PUT_STATE,
 };
 
 enum lunatik_attrs {
@@ -63,6 +64,7 @@ enum lunatik_attrs {
 	LUNATIK_DATA_LEN,
 	CURR_ALLOC,
 	STATE_NOT_FOUND,
+	NOT_IN_USE,
 	ATTRS_COUNT
 #define ATTRS_MAX	(ATTRS_COUNT - 1)
 };
diff --git a/states.c b/states.c
@@ -146,24 +146,29 @@ inline bool lunatik_getstate(lunatik_State *s)
 	return refcount_inc_not_zero(&s->users);
 }
 
-void lunatik_putstate(lunatik_State *s)
+int lunatik_putstate(lunatik_State *s)
 {
 	refcount_t *users = &s->users;
 	spinlock_t *refcnt_lock = &(s->instance.rfcnt_lock);
 
 	if (WARN_ON(s == NULL))
-		return;
+		return 1;
 
 	if (refcount_dec_not_one(users))
-		return;
+		return 1;
 
 	spin_lock_bh(refcnt_lock);
 	if (!refcount_dec_and_test(users))
-		goto out;
+		goto error_and_unlock;
 
+	hash_del_rcu(&s->node);
 	kfree(s);
-out:
 	spin_unlock_bh(refcnt_lock);
+	return 0;
+
+error_and_unlock:
+	spin_unlock_bh(refcnt_lock);
+	return 1;
 }
 
 lunatik_State *lunatik_netstatelookup(const char *name, struct net *net)

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,4 @@`
`1`		`-ccflags-y += -D_LUNATIK -D_KERNEL -I$(src) -D_CONFIG_FULL_PANIC -DLUNATIK_UNUSED \`
	`1`	`+ccflags-y += -D_LUNATIK -D_KERNEL -I$(src) -D_CONFIG_FULL_PANIC -DLUNATIK_UNUSED -DDEBUG\`
`2`	`2`	`-I$(src)/lua -I$(src)/deps/lua-memory/src`
`3`	`3`	`asflags-y += -D_LUNATIK -D_KERNEL`
`4`	`4`