/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
#include "simgrid_lua.h"
+#include <string.h> // memcpy
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(lua, bindings, "Lua Bindings");
#define AS_MODULE_NAME "simgrid.AS"
#define TRACE_MODULE_NAME "simgrid.Trace"
-static void stack_dump(const char *msg, lua_State *L);
+/**
+ * @brief A chunk of memory.
+ *
+ * TODO replace this by a dynar
+ */
+typedef struct s_buffer {
+ char* data;
+ size_t size;
+ size_t capacity;
+} s_buffer_t, *buffer_t;
+
+static const char* value_tostring(lua_State* L, int index);
+static const char* keyvalue_tostring(lua_State* L, int key_index, int value_index);
+static void stack_dump(const char *msg, lua_State* L);
+static int writer(lua_State* L, const void* source, size_t size, void* userdata);
+static void move_value(lua_State* dst, lua_State* src, const char* name);
+static int l_get_from_father(lua_State* L);
+static lua_State *clone_lua_state(lua_State* L);
static m_task_t check_task(lua_State *L, int index);
static void register_c_functions(lua_State *L);
/* ********************************************************************************* */
/**
- * @brief Dumps the Lua stack
+ * @brief Returns a string representation of a value in the Lua stack.
+ *
+ * This function is for debugging purposes.
+ * It always returns the same pointer.
+ *
+ * @param L the Lua state
+ * @param index index in the stack
+ * @return a string representation of the value at this index
+ */
+static const char* value_tostring(lua_State* L, int index) {
+
+ static char buff[64];
+
+ switch (lua_type(L, index)) {
+
+ case LUA_TNIL:
+ sprintf(buff, "nil");
+ break;
+
+ case LUA_TNUMBER:
+ sprintf(buff, "%.3f", lua_tonumber(L, index));
+ break;
+
+ case LUA_TBOOLEAN:
+ sprintf(buff, "%s", lua_toboolean(L, index) ? "true" : "false");
+ break;
+
+ case LUA_TSTRING:
+ snprintf(buff, 63, "'%s'", lua_tostring(L, index));
+ break;
+
+ case LUA_TFUNCTION:
+ if (lua_iscfunction(L, index)) {
+ sprintf(buff, "C-function");
+ }
+ else {
+ sprintf(buff, "function");
+ }
+ break;
+
+ case LUA_TTABLE:
+ sprintf(buff, "table(%d)", lua_objlen(L, index));
+ break;
+
+ case LUA_TLIGHTUSERDATA:
+ case LUA_TUSERDATA:
+ sprintf(buff, "userdata(%p)", lua_touserdata(L, index));
+ break;
+
+ case LUA_TTHREAD:
+ sprintf(buff, "thread");
+ break;
+ }
+ return buff;
+}
+
+/**
+ * @brief Returns a string representation of a key-value pair.
+ *
+ * This function is for debugging purposes.
+ * It always returns the same pointer.
+ *
+ * @param L the Lua state
+ * @param key_index index of the key
+ * @param value_index index of the value
+ * @return a string representation of the key-value pair
+ */
+static const char* keyvalue_tostring(lua_State* L, int key_index, int value_index) {
+
+ static char buff[64];
+ /* value_tostring also always returns the same pointer */
+ int len = snprintf(buff, 63, "%s -> ", value_tostring(L, key_index));
+ snprintf(buff + len, 63 - len, "%s", value_tostring(L, value_index));
+ return buff;
+}
+
+/**
+ * @brief Dumps the Lua stack if debug logs are enabled.
* @param msg a message to print
* @param L a Lua state
*/
-static void stack_dump(const char *msg, lua_State *L)
+static void stack_dump(const char* msg, lua_State* L)
{
- char buff[2048];
- char *p = buff;
- int i;
- int top = lua_gettop(L);
+ if (XBT_LOG_ISENABLED(lua, xbt_log_priority_debug)) {
+ char buff[2048];
+ char* p = buff;
+ int i;
+ int top = lua_gettop(L);
+
+ // if (1) return;
+
+ fflush(stdout);
+
+ p[0] = '\0';
+ for (i = 1; i <= top; i++) { /* repeat for each level */
+
+ p += sprintf(p, "%s", value_tostring(L, i));
+ p += sprintf(p, " "); /* put a separator */
+ }
+ XBT_DEBUG("%s%s", msg, buff);
+ }
+}
+
+/**
+ * @brief Writes the specified data into a memory buffer.
+ *
+ * This function is a valid lua_Writer that writes into a memory buffer passed
+ * as userdata.
+ *
+ * @param L a lua state
+ * @param source some data
+ * @param sz number of bytes of data
+ * @param user_data the memory buffer to write
+ */
+static int writer(lua_State* L, const void* source, size_t size, void* userdata) {
+
+ buffer_t buffer = (buffer_t) userdata;
+ while (buffer->capacity < buffer->size + size) {
+ buffer->capacity *= 2;
+ buffer->data = xbt_realloc(buffer->data, buffer->capacity);
+ }
+ memcpy(buffer->data + buffer->size, source, size);
+ buffer->size += size;
+
+ return 0;
+}
+
+/**
+ * @brief Pops a value from the stack of a source state and pushes it on the
+ * stack of another state.
+ *
+ * If the value is a table, its content is copied recursively. To avoid cycles,
+ * a table of previsously visited tables must be present at index 1 of dst.
+ * Its keys are pointers to visited tables in src and its values are the tables
+ * already built.
+ *
+ * TODO: add support of upvalues
+ *
+ * @param src the source state
+ * @param dst the destination state
+ * @param name a name describing the value
+ */
+static void move_value(lua_State* dst, lua_State *src, const char* name) {
+
+ luaL_checkany(src, -1); /* check the value to copy */
+ luaL_checktype(dst, 1, LUA_TTABLE); /* check the presence of a table of
+ previously visited tables */
+
+ XBT_DEBUG("Copying value %s", name);
+
+ stack_dump("src before copying a value (should be ... value): ", src);
+ stack_dump("dst before copying a value (should be visited ...): ", dst);
- fflush(stdout);
- p += sprintf(p, "STACK(top=%d): ", top);
+ switch (lua_type(src, -1)) {
- for (i = 1; i <= top; i++) { /* repeat for each level */
- int t = lua_type(L, i);
- switch (t) {
+ case LUA_TNIL:
+ lua_pushnil(dst);
+ break;
+
+ case LUA_TNUMBER:
+ lua_pushnumber(dst, lua_tonumber(src, -1));
+ break;
- case LUA_TSTRING: /* strings */
- p += sprintf(p, "`%s'", lua_tostring(L, i));
+ case LUA_TBOOLEAN:
+ lua_pushboolean(dst, lua_toboolean(src, -1));
break;
- case LUA_TBOOLEAN: /* booleans */
- p += sprintf(p, lua_toboolean(L, i) ? "true" : "false");
+ case LUA_TSTRING:
+ /* no worries about memory: lua_pushstring makes a copy */
+ lua_pushstring(dst, lua_tostring(src, -1));
break;
- case LUA_TNUMBER: /* numbers */
- p += sprintf(p, "%g", lua_tonumber(L, i));
+ case LUA_TFUNCTION:
+ /* it's a function that does not exist yet in L2 */
+
+ if (lua_iscfunction(src, -1)) {
+ /* it's a C function: just copy the pointer */
+ XBT_DEBUG("Copying C function '%s'", name);
+ lua_CFunction f = lua_tocfunction(src, -1);
+ lua_pushcfunction(dst, f);
+ }
+ else {
+ /* it's a Lua function: dump it from src */
+ XBT_DEBUG("Dumping Lua function '%s'", name);
+
+ s_buffer_t buffer;
+ buffer.capacity = 64;
+ buffer.size = 0;
+ buffer.data = xbt_new(char, buffer.capacity);
+
+ /* copy the binary chunk from src into a buffer */
+ int error = lua_dump(src, writer, &buffer);
+ xbt_assert(!error, "Failed to dump function '%s' from the source state: error %d",
+ name, error);
+
+ /* load the chunk into dst */
+ error = luaL_loadbuffer(dst, buffer.data, buffer.size, name);
+ xbt_assert(!error, "Failed to load function '%s' from the source state: %s",
+ name, lua_tostring(dst, -1));
+ XBT_DEBUG("Function '%s' successfully dumped from source state.", name);
+ }
break;
case LUA_TTABLE:
- p += sprintf(p, "Table");
+
+ /* see if this table was already visited */
+ lua_pushlightuserdata(dst, (void*) lua_topointer(src, -1));
+ /* dst: visited ... psrctable */
+ lua_gettable(dst, 1);
+ /* dst: visited ... table/nil */
+ if (lua_istable(dst, -1)) {
+ XBT_DEBUG("Nothing to do: table already visited");
+ /* dst: visited ... table */
+ }
+ else {
+ XBT_DEBUG("First visit of this table");
+ /* dst: visited ... nil */
+ lua_pop(dst, 1);
+ /* dst: visited ... */
+
+ /* first visit: create the new table in dst */
+ lua_newtable(dst);
+ /* dst: visited ... table */
+
+ /* mark the table as visited to avoid infinite recursion */
+ lua_pushlightuserdata(dst, (void*) lua_topointer(src, -1));
+ /* dst: visited ... table psrctable */
+ lua_pushvalue(dst, -2);
+ /* dst: visited ... table psrctable table */
+ lua_settable(dst, 1);
+ /* dst: visited ... table */
+ XBT_DEBUG("Table marked as visited");
+
+ stack_dump("dst after marking the table as visited (should be visited ... table): ", dst);
+
+ /* copy the metatable if any */
+ int has_meta_table = lua_getmetatable(src, -1);
+ /* src: ... table mt? */
+ if (has_meta_table) {
+ XBT_DEBUG("Copying metatable");
+ /* src: ... table mt */
+ move_value(dst, src, "metatable");
+ /* src: ... table
+ dst: visited ... table mt */
+ lua_setmetatable(dst, -2);
+ /* dst: visited ... table */
+ }
+ else {
+ XBT_DEBUG("No metatable");
+ }
+
+ stack_dump("src before traversing the table (should be ... table): ", src);
+ stack_dump("dst before traversing the table (should be visited ... table): ", dst);
+
+ /* traverse the table of src and copy each element */
+ lua_pushnil(src);
+ /* src: ... table nil */
+ while (lua_next(src, -2) != 0) {
+ /* src: ... table key value */
+
+ XBT_DEBUG("Copying table element %s", keyvalue_tostring(src, -2, -1));
+
+ stack_dump("src before copying table element (should be ... table key value): ", src);
+ stack_dump("dst before copying table element (should be visited ... table): ", dst);
+
+ /* copy the key */
+ lua_pushvalue(src, -2);
+ /* src: ... table key value key */
+ XBT_DEBUG("Copying the element key");
+ move_value(dst, src, value_tostring(src, -1));
+ /* src: ... table key value
+ dst: visited ... table key */
+ XBT_DEBUG("Copied the element key");
+
+ /* copy the value */
+ XBT_DEBUG("Copying the element value");
+ move_value(dst, src, value_tostring(src, -1));
+ /* src: ... table key
+ dst: visited ... table key value */
+ XBT_DEBUG("Copied the element value");
+
+ /* set the table element */
+ lua_settable(dst, -3);
+ /* dst: visited ... table */
+
+ /* the key stays on top of src for next iteration */
+ stack_dump("src before next iteration (should be ... table key): ", src);
+ stack_dump("dst before next iteration (should be visited ... table): ", dst);
+ }
+ XBT_DEBUG("Finished traversing the table");
+ }
break;
- default: /* other values */
- p += sprintf(p, "???");
-/* if ((ptr = luaL_checkudata(L,i,TASK_MODULE_NAME))) {
- p+=sprintf(p,"task");
- } else {
- p+=printf(p,"%s", lua_typename(L, t));
- }*/
+ case LUA_TLIGHTUSERDATA:
+ lua_pushlightuserdata(dst, lua_touserdata(src, -1));
break;
- }
- p += sprintf(p, " "); /* put a separator */
+ case LUA_TUSERDATA:
+ XBT_WARN("Cannot copy a full userdata from the source state.");
+ lua_pushnil(dst);
+ break;
+
+ case LUA_TTHREAD:
+ XBT_WARN("Cannot copy a thread from the source state.");
+ lua_pushnil(dst);
+ break;
}
- XBT_INFO("%s%s", msg, buff);
+
+ /* pop the value from src */
+ lua_pop(src, 1);
+
+ stack_dump("src after copying a value (should be ...): ", src);
+ stack_dump("dst after copying a value (should be visited ... value): ", dst);
+}
+
+/**
+ * @brief Copies a global value from the father state.
+ *
+ * The state L must have a father, i.e. it should have been created by
+ * clone_lua_state().
+ * This function is meant to be an __index metamethod.
+ * Consequently, it assumes that the stack has two elements:
+ * a table (usually the environment of L) and the string key of a value
+ * that does not exist yet in this table. It copies the corresponding global
+ * value from the father state and pushes it on the stack of L.
+ * If the global value does not exist in the father state either, nil is
+ * pushed.
+ *
+ * TODO: make this function thread safe. If the simulation runs in parallel,
+ * several simulated processes may trigger this __index metamethod at the same
+ * time and get globals from maestro.
+ *
+ * @param L the current state
+ * @return number of return values pushed (always 1)
+ */
+static int l_get_from_father(lua_State *L) {
+
+ /* retrieve the father */
+ lua_getfield(L, LUA_REGISTRYINDEX, "simgrid.father_state");
+ lua_State* father = lua_touserdata(L, -1);
+ xbt_assert(father != NULL, "This Lua state has no father");
+ lua_pop(L, 1);
+
+ /* get the global from the father */
+ const char* key = luaL_checkstring(L, 2); /* L: table key */
+ lua_getglobal(father, key); /* father: ... value */
+ XBT_DEBUG("__index of '%s' begins", key);
+
+ /* push the value onto the stack of L */
+ lua_newtable(L); /* L: table key visited */
+ lua_insert(L, 1); /* L: visited table key */
+ move_value(L, father, key); /* father: ...
+ L: visited table key value */
+ lua_remove(L, 1); /* L: table key value */
+
+ /* prepare the return value of __index */
+ lua_pushvalue(L, -1); /* L: table key value value */
+ lua_insert(L, 1); /* L: value table key value */
+
+ /* save the copied value in the table for subsequent accesses */
+ lua_settable(L, -3); /* L: value table */
+ lua_remove(L, 2); /* L: value */
+
+ XBT_DEBUG("__index of '%s' returns %s", key, value_tostring(L, -1));
+
+ return 1;
+}
+
+/**
+ * @brief Creates a new Lua state and get its environment from an existing state.
+ *
+ * The state created is independent from the existing one and has its own
+ * copies of global variables and functions.
+ * However, the global variables and functions are not copied right now from
+ * the original state; they are copied only the first time they are accessed.
+ * This behavior saves time and memory, and is okay for Simgrid's needs.
+ *
+ * @param father an existing state
+ * @return the state created
+ */
+static lua_State* clone_lua_state(lua_State *father) {
+
+ /* create the new state */
+ lua_State *L = luaL_newstate();
+
+ /* set its environment:
+ * - create a table newenv
+ * - create a metatable mt
+ * - set mt.__index = a function that copies the global from the father state
+ * - set mt as the metatable of newenv
+ * - set newenv as the environment of the new state
+ */
+ lua_pushthread(L); /* thread */
+ lua_newtable(L); /* thread newenv */
+ lua_newtable(L); /* thread newenv mt */
+ lua_pushcfunction(L, l_get_from_father); /* thread newenv mt f */
+ lua_setfield(L, -2, "__index"); /* thread newenv mt */
+ lua_setmetatable(L, -2); /* thread newenv */
+ lua_setfenv(L, -2); /* thread */
+ lua_pop(L, 1); /* -- */
+
+ /* open the standard libs (theoretically, this is not necessary) */
+ luaL_openlibs(L);
+
+ /* put a pointer to the father */
+ lua_pushlightuserdata(L, father);
+ lua_setfield(L, LUA_REGISTRYINDEX, "simgrid.father_state");
+
+ XBT_DEBUG("New state created");
+
+ return L;
}
/**
{
XBT_DEBUG("Run lua code %s", argv[0]);
- lua_State *L = lua_newthread(lua_maestro_state);
- int ref = luaL_ref(lua_maestro_state, LUA_REGISTRYINDEX); /* protect the thread from being garbage collected */
+ lua_State *L = clone_lua_state(lua_maestro_state);
int res = 1;
- /* start the co-routine */
+ /* start the function */
lua_getglobal(L, argv[0]);
xbt_assert(lua_isfunction(L, -1),
"The lua function %s does not seem to exist", argv[0]);
lua_pop(L, 1); /* pop returned value */
}
- /* cleanups */
- luaL_unref(lua_maestro_state, LUA_REGISTRYINDEX, ref);
XBT_DEBUG("Execution of Lua code %s is over", (argv ? argv[0] : "(null)"));
return res;
