diff options
Diffstat (limited to 'indra/llcommon')
| -rw-r--r-- | indra/llcommon/CMakeLists.txt | 4 | ||||
| -rw-r--r-- | indra/llcommon/lua_function.cpp | 575 | ||||
| -rw-r--r-- | indra/llcommon/lua_function.h | 193 | ||||
| -rw-r--r-- | indra/llcommon/lualistener.cpp | 103 | ||||
| -rw-r--r-- | indra/llcommon/lualistener.h | 77 |
5 files changed, 952 insertions, 0 deletions
diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt index 5f4ed2fffa..990d661e38 100644 --- a/indra/llcommon/CMakeLists.txt +++ b/indra/llcommon/CMakeLists.txt @@ -107,6 +107,8 @@ set(llcommon_SOURCE_FILES lluriparser.cpp lluuid.cpp llworkerthread.cpp + lua_function.cpp + lualistener.cpp hbxxh.cpp u64.cpp threadpool.cpp @@ -249,6 +251,8 @@ set(llcommon_HEADER_FILES llwin32headers.h llwin32headerslean.h llworkerthread.h + lua_function.h + lualistener.h hbxxh.h lockstatic.h stdtypes.h diff --git a/indra/llcommon/lua_function.cpp b/indra/llcommon/lua_function.cpp new file mode 100644 index 0000000000..f6db4eafe1 --- /dev/null +++ b/indra/llcommon/lua_function.cpp @@ -0,0 +1,575 @@ +/** + * @file lua_function.cpp + * @author Nat Goodspeed + * @date 2024-02-05 + * @brief Implementation for lua_function. + * + * $LicenseInfo:firstyear=2024&license=viewerlgpl$ + * Copyright (c) 2024, Linden Research, Inc. + * $/LicenseInfo$ + */ + +// Precompiled header +#include "linden_common.h" +// associated header +#include "lua_function.h" +// STL headers +// std headers +#include <algorithm> +#include <map> +#include <memory> // std::unique_ptr +// external library headers +// other Linden headers +#include "hexdump.h" +#include "llsd.h" +#include "llsdutil.h" +#include "lualistener.h" + +namespace +{ + // can't specify free function free() as a unique_ptr deleter + struct freer + { + void operator()(void* ptr){ free(ptr); } + }; +} // anonymous namespace + +int lluau::dostring(lua_State* L, const std::string& desc, const std::string& text) +{ + { + size_t bytecodeSize = 0; + // The char* returned by luau_compile() must be freed by calling free(). + // Use unique_ptr so the memory will be freed even if luau_load() throws. + std::unique_ptr<char[], freer> bytecode{ + luau_compile(text.data(), text.length(), nullptr, &bytecodeSize)}; + auto r = luau_load(L, desc.data(), bytecode.get(), bytecodeSize, 0); + if (r != LUA_OK) + return r; + } // free bytecode + + return lua_pcall(L, 0, 0, 0); +} + +std::string lua_tostdstring(lua_State* L, int index) +{ + size_t len; + const char* strval{ lua_tolstring(L, index, &len) }; + return { strval, len }; +} + +void lua_pushstdstring(lua_State* L, const std::string& str) +{ + luaL_checkstack(L, 1, nullptr); + lua_pushlstring(L, str.c_str(), str.length()); +} + +// By analogy with existing lua_tomumble() functions, return an LLSD object +// corresponding to the Lua object at stack index 'index' in state L. +// This function assumes that a Lua caller is fully aware that they're trying +// to call a viewer function. In other words, the caller must specifically +// construct Lua data convertible to LLSD. +// +// For proper error handling, we REQUIRE that the Lua runtime be compiled as +// C++ so errors are raised as C++ exceptions rather than as longjmp() calls: +// http://www.lua.org/manual/5.4/manual.html#4.4 +// "Internally, Lua uses the C longjmp facility to handle errors. (Lua will +// use exceptions if you compile it as C++; search for LUAI_THROW in the +// source code for details.)" +// Some blocks within this function construct temporary C++ objects in the +// expectation that these objects will be properly destroyed even if code +// reached by that block raises a Lua error. +LLSD lua_tollsd(lua_State* L, int index) +{ + LL_DEBUGS("Lua") << "lua_tollsd(" << index << ") of " << lua_gettop(L) << " stack entries: " + << lua_what(L, index) << LL_ENDL; + DebugExit log_exit("lua_tollsd()"); + switch (lua_type(L, index)) + { + case LUA_TNONE: + // Should LUA_TNONE be an error instead of returning isUndefined()? + case LUA_TNIL: + return {}; + + case LUA_TBOOLEAN: + return bool(lua_toboolean(L, index)); + + case LUA_TNUMBER: + { + // check if integer truncation leaves the number intact + int isint; + lua_Integer intval{ lua_tointegerx(L, index, &isint) }; + if (isint) + { + return LLSD::Integer(intval); + } + else + { + return lua_tonumber(L, index); + } + } + + case LUA_TSTRING: + return lua_tostdstring(L, index); + + case LUA_TUSERDATA: + { + LLSD::Binary binary(lua_rawlen(L, index)); + std::memcpy(binary.data(), lua_touserdata(L, index), binary.size()); + return binary; + } + + case LUA_TTABLE: + { + // A Lua table correctly constructed to convert to LLSD will have + // either consecutive integer keys starting at 1, which we represent + // as an LLSD array (with Lua key 1 at C++ index 0), or will have + // all string keys. + // + // In the belief that Lua table traversal skips "holes," that is, it + // doesn't report any key/value pair whose value is nil, we allow a + // table with integer keys >= 1 but with "holes." This produces an + // LLSD array with isUndefined() entries at unspecified keys. There + // would be no other way for a Lua caller to construct an + // isUndefined() LLSD array entry. However, to guard against crazy int + // keys, we forbid gaps larger than a certain size: crazy int keys + // could result in a crazy large contiguous LLSD array. + // + // Possible looseness could include: + // - A mix of integer and string keys could produce an LLSD map in + // which the integer keys are converted to string. (Key conversion + // must be performed in C++, not Lua, to avoid confusing + // lua_next().) + // - However, since in Lua t[0] and t["0"] are distinct table entries, + // do not consider converting numeric string keys to int to return + // an LLSD array. + // But until we get more experience with actual Lua scripts in + // practice, let's say that any deviation is a Lua coding error. + // An important property of the strict definition above is that most + // conforming data blobs can make a round trip across the language + // boundary and still compare equal. A non-conforming data blob would + // lose that property. + // Known exceptions to round trip identity: + // - Empty LLSD map and empty LLSD array convert to empty Lua table. + // But empty Lua table converts to isUndefined() LLSD object. + // - LLSD::Real with integer value returns as LLSD::Integer. + // - LLSD::UUID, LLSD::Date and LLSD::URI all convert to Lua string, + // and so return as LLSD::String. + // - Lua does not store any table key whose value is nil. An LLSD + // array with isUndefined() entries produces a Lua table with + // "holes" in the int key sequence; this converts back to an LLSD + // array containing corresponding isUndefined() entries -- except + // when one or more of the final entries isUndefined(). These are + // simply dropped, producing a shorter LLSD array than the original. + // - For the same reason, any keys in an LLSD map whose value + // isUndefined() are simply discarded in the converted Lua table. + // This converts back to an LLSD map lacking those keys. + // - If it's important to preserve the original length of an LLSD + // array whose final entries are undefined, or the full set of keys + // for an LLSD map some of whose values are undefined, store an + // LLSD::emptyArray() or emptyMap() instead. These will be + // represented in Lua as empty table, which should convert back to + // undefined LLSD. Naturally, though, those won't survive a second + // round trip. + + // This is the most important of the luaL_checkstack() calls because a + // deeply nested Lua structure will enter this case at each level, and + // we'll need another 2 stack slots to traverse each nested table. + luaL_checkstack(L, 2, nullptr); + // BEFORE we push nil to initialize the lua_next() traversal, convert + // 'index' to absolute! Our caller might have passed a relative index; + // we do, below: lua_tollsd(L, -1). If 'index' is -1, then when we + // push nil, what we find at index -1 is nil, not the table! + index = lua_absindex(L, index); + LL_DEBUGS("Lua") << "checking for empty table" << LL_ENDL; + lua_pushnil(L); // first key + LL_DEBUGS("Lua") << lua_stack(L) << LL_ENDL; + if (! lua_next(L, index)) + { + // it's a table, but the table is empty -- no idea if it should be + // modeled as empty array or empty map -- return isUndefined(), + // which can be consumed as either + LL_DEBUGS("Lua") << "empty table" << LL_ENDL; + return {}; + } + // key is at stack index -2, value at index -1 + // from here until lua_next() returns 0, have to lua_pop(2) if we + // return early + LuaPopper popper(L, 2); + // Remember the type of the first key + auto firstkeytype{ lua_type(L, -2) }; + LL_DEBUGS("Lua") << "table not empty, first key type " << lua_typename(L, firstkeytype) + << LL_ENDL; + switch (firstkeytype) + { + case LUA_TNUMBER: + { + // First Lua key is a number: try to convert table to LLSD array. + // This is tricky because we don't know in advance the size of the + // array. The Lua reference manual says that lua_rawlen() is the + // same as the length operator '#'; but the length operator states + // that it might stop at any "hole" in the subject table. + // Moreover, the Lua next() function (and presumably lua_next()) + // traverses a table in unspecified order, even for numeric keys + // (emphasized in the doc). + // Make a preliminary pass over the whole table to validate and to + // collect keys. + std::vector<LLSD::Integer> keys; + // Try to determine the length of the table. If the length + // operator is truthful, avoid allocations while we grow the keys + // vector. Even if it's not, we can still grow the vector, albeit + // a little less efficiently. + keys.reserve(lua_objlen(L, index)); + do + { + auto arraykeytype{ lua_type(L, -2) }; + switch (arraykeytype) + { + case LUA_TNUMBER: + { + int isint; + lua_Integer intkey{ lua_tointegerx(L, -2, &isint) }; + if (! isint) + { + // key isn't an integer - this doesn't fit our LLSD + // array constraints + return lluau::error(L, "Expected integer array key, got %f instead", + lua_tonumber(L, -2)); + } + if (intkey < 1) + { + return lluau::error(L, "array key %d out of bounds", int(intkey)); + } + + keys.push_back(LLSD::Integer(intkey)); + break; + } + + case LUA_TSTRING: + // break out strings specially to report the value + return lluau::error(L, "Cannot convert string array key '%s' to LLSD", + lua_tostring(L, -2)); + + default: + return lluau::error(L, "Cannot convert %s array key to LLSD", + lua_typename(L, arraykeytype)); + } + + // remove value, keep key for next iteration + lua_pop(L, 1); + } while (lua_next(L, index) != 0); + popper.disarm(); + // Table keys are all integers: are they reasonable integers? + // Arbitrary max: may bite us, but more likely to protect us + size_t array_max{ 10000 }; + if (keys.size() > array_max) + { + return lluau::error(L, "Conversion from Lua to LLSD array limited to %d entries", + int(array_max)); + } + // We know the smallest key is >= 1. Check the largest. We also + // know the vector is NOT empty, else we wouldn't have gotten here. + std::sort(keys.begin(), keys.end()); + LLSD::Integer highkey = *keys.rbegin(); + if ((highkey - LLSD::Integer(keys.size())) > 100) + { + // Looks like we've gone beyond intentional array gaps into + // crazy key territory. + return lluau::error(L, "Gaps in Lua table too large for conversion to LLSD array"); + } + LL_DEBUGS("Lua") << "collected " << keys.size() << " keys, max " << highkey << LL_ENDL; + // right away expand the result array to the size we'll need + LLSD result{ LLSD::emptyArray() }; + result[highkey - 1] = LLSD(); + // Traverse the table again, and this time populate result array. + lua_pushnil(L); // first key + while (lua_next(L, index)) + { + // key at stack index -2, value at index -1 + // We've already validated lua_tointegerx() for each key. + auto key{ lua_tointeger(L, -2) }; + LL_DEBUGS("Lua") << "key " << key << ':' << LL_ENDL; + // Don't forget to subtract 1 from Lua key for LLSD subscript! + result[LLSD::Integer(key) - 1] = lua_tollsd(L, -1); + // remove value, keep key for next iteration + lua_pop(L, 1); + } + return result; + } + + case LUA_TSTRING: + { + // First Lua key is a string: try to convert table to LLSD map + LLSD result{ LLSD::emptyMap() }; + do + { + auto mapkeytype{ lua_type(L, -2) }; + if (mapkeytype != LUA_TSTRING) + { + return lluau::error(L, "Cannot convert %s map key to LLSD", + lua_typename(L, mapkeytype)); + } + + auto key{ lua_tostdstring(L, -2) }; + LL_DEBUGS("Lua") << "map key " << std::quoted(key) << ':' << LL_ENDL; + result[key] = lua_tollsd(L, -1); + // remove value, keep key for next iteration + lua_pop(L, 1); + } while (lua_next(L, index) != 0); + popper.disarm(); + return result; + } + + default: + // First Lua key isn't number or string: sorry + return lluau::error(L, "Cannot convert %s table key to LLSD", + lua_typename(L, firstkeytype)); + } + } + + default: + // Other Lua entities (e.g. function, C function, light userdata, + // thread, userdata) are not convertible to LLSD, indicating a coding + // error in the caller. + return lluau::error(L, "Cannot convert type %s to LLSD", luaL_typename(L, index)); + } +} + +// By analogy with existing lua_pushmumble() functions, push onto state L's +// stack a Lua object corresponding to the passed LLSD object. +void lua_pushllsd(lua_State* L, const LLSD& data) +{ + // might need 2 slots for array or map + luaL_checkstack(L, 2, nullptr); + switch (data.type()) + { + case LLSD::TypeUndefined: + lua_pushnil(L); + break; + + case LLSD::TypeBoolean: + lua_pushboolean(L, data.asBoolean()); + break; + + case LLSD::TypeInteger: + lua_pushinteger(L, data.asInteger()); + break; + + case LLSD::TypeReal: + lua_pushnumber(L, data.asReal()); + break; + + case LLSD::TypeBinary: + { + auto binary{ data.asBinary() }; + std::memcpy(lua_newuserdata(L, binary.size()), + binary.data(), binary.size()); + break; + } + + case LLSD::TypeMap: + { + // push a new table with space for our non-array keys + lua_createtable(L, 0, data.size()); + for (const auto& pair: llsd::inMap(data)) + { + // push value -- so now table is at -2, value at -1 + lua_pushllsd(L, pair.second); + // pop value, assign to table[key] + lua_setfield(L, -2, pair.first.c_str()); + } + break; + } + + case LLSD::TypeArray: + { + // push a new table with space for array entries + lua_createtable(L, data.size(), 0); + lua_Integer key{ 0 }; + for (const auto& item: llsd::inArray(data)) + { + // push new array value: table at -2, value at -1 + lua_pushllsd(L, item); + // pop value, assign table[key] = value + lua_rawseti(L, -2, ++key); + } + break; + } + + case LLSD::TypeString: + case LLSD::TypeUUID: + case LLSD::TypeDate: + case LLSD::TypeURI: + default: + { + lua_pushstdstring(L, data.asString()); + break; + } + } +} + +LuaState::LuaState(const std::string_view& desc, script_finished_fn cb): + mDesc(desc), + mCallback(cb), + mState(luaL_newstate()) +{ + luaL_openlibs(mState); + LuaFunction::init(mState); + // Try to make print() write to our log. + lua_register(mState, "print", LuaFunction::get("print_info")); +} + +LuaState::~LuaState() +{ + // Did somebody call listen_events() on this LuaState? + // That is, is there a LuaListener key in its registry? + auto keytype{ lua_getfield(mState, LUA_REGISTRYINDEX, "event.listener") }; + if (keytype == LUA_TNUMBER) + { + // We do have a LuaListener. Retrieve it. + int isint; + auto listener{ LuaListener::getInstance(lua_tointegerx(mState, -1, &isint)) }; + // pop the int "event.listener" key + lua_pop(mState, 1); + // if we got a LuaListener instance, destroy it + // (if (! isint), lua_tointegerx() returned 0, but key 0 might + // validly designate someone ELSE's LuaListener) + if (isint && listener) + { + auto lptr{ listener.get() }; + listener.reset(); + delete lptr; + } + } + + lua_close(mState); + + if (mCallback) + { + // mError potentially set by previous checkLua() call(s) + mCallback(mError); + } +} + +bool LuaState::checkLua(int r) +{ + if (r != LUA_OK) + { + mError = lua_tostring(mState, -1); + lua_pop(mState, 1); + + LL_WARNS() << mDesc << ": " << mError << LL_ENDL; + return false; + } + return true; +} + + +LuaPopper::~LuaPopper() +{ + if (mCount) + { + lua_pop(mState, mCount); + } +} + +LuaFunction::LuaFunction(const std::string_view& name, lua_CFunction function) +{ + getRegistry().emplace(name, function); +} + +void LuaFunction::init(lua_State* L) +{ + for (const auto& pair: getRegistry()) + { + lua_register(L, pair.first.c_str(), pair.second); + } +} + +lua_CFunction LuaFunction::get(const std::string& key) +{ + // use find() instead of subscripting to avoid creating an entry for + // unknown key + const auto& registry{ getRegistry() }; + auto found{ registry.find(key) }; + return (found == registry.end())? nullptr : found->second; +} + +LuaFunction::Registry& LuaFunction::getRegistry() +{ + // use a function-local static to ensure it's initialized + static Registry registry; + return registry; +} + + +std::ostream& operator<<(std::ostream& out, const lua_what& self) +{ + switch (lua_type(self.L, self.index)) + { + case LUA_TNONE: + // distinguish acceptable but non-valid index + out << "none"; + break; + + case LUA_TNIL: + out << "nil"; + break; + + case LUA_TBOOLEAN: + { + auto oldflags { out.flags() }; + out << std::boolalpha << lua_toboolean(self.L, self.index); + out.flags(oldflags); + break; + } + + case LUA_TNUMBER: + out << lua_tonumber(self.L, self.index); + break; + + case LUA_TSTRING: + out << std::quoted(lua_tostdstring(self.L, self.index)); + break; + + case LUA_TUSERDATA: + { + const S32 maxlen = 20; + S32 binlen{ lua_rawlen(self.L, self.index) }; + LLSD::Binary binary(std::min(maxlen, binlen)); + std::memcpy(binary.data(), lua_touserdata(self.L, self.index), binary.size()); + out << LL::hexdump(binary); + if (binlen > maxlen) + { + out << "...(" << (binlen - maxlen) << " more)"; + } + break; + } + + case LUA_TLIGHTUSERDATA: + out << lua_touserdata(self.L, self.index); + break; + + default: + // anything else, don't bother trying to report value, just type + out << lua_typename(self.L, lua_type(self.L, self.index)); + break; + } + return out; +} + +std::ostream& operator<<(std::ostream& out, const lua_stack& self) +{ + const char* sep = "stack: ["; + for (int index = 1; index <= lua_gettop(self.L); ++index) + { + out << sep << lua_what(self.L, index); + sep = ", "; + } + out << ']'; + return out; +} + +DebugExit::~DebugExit() +{ + LL_DEBUGS("Lua") << "exit " << mName << LL_ENDL; +} diff --git a/indra/llcommon/lua_function.h b/indra/llcommon/lua_function.h new file mode 100644 index 0000000000..e2bd58e80a --- /dev/null +++ b/indra/llcommon/lua_function.h @@ -0,0 +1,193 @@ +/** + * @file lua_function.h + * @author Nat Goodspeed + * @date 2024-02-05 + * @brief Definitions useful for coding a new Luau entry point into C++ + * + * $LicenseInfo:firstyear=2024&license=viewerlgpl$ + * Copyright (c) 2024, Linden Research, Inc. + * $/LicenseInfo$ + */ + +#if ! defined(LL_LUA_FUNCTION_H) +#define LL_LUA_FUNCTION_H + +#include "luau/luacode.h" +#include "luau/lua.h" +#include "luau/luaconf.h" +#include "luau/lualib.h" +#include "stringize.h" + +#define lua_register(L, n, f) (lua_pushcfunction(L, (f), n), lua_setglobal(L, (n))) +#define lua_rawlen lua_objlen + +namespace lluau +{ + // luau defines luaL_error() as void, but we want to use the Lua idiom of + // 'return error(...)'. Wrap luaL_error() in an int function. +#pragma clang diagnostic push +#pragma clang diagnostic ignored "-Wformat-security" + template<typename... Args> + int error(lua_State* L, const char* format, Args&&... args) + { + luaL_error(L, format, std::forward<Args>(args)...); + return 0; + } +#pragma clang diagnostic pop + + // luau removed lua_dostring(), but since we perform the equivalent luau + // sequence in multiple places, encapsulate it. desc and text are strings + // rather than string_views because dostring() needs pointers to nul- + // terminated char arrays. + int dostring(lua_State* L, const std::string& desc, const std::string& text); +} // namespace lluau + +std::string lua_tostdstring(lua_State* L, int index); +void lua_pushstdstring(lua_State* L, const std::string& str); +LLSD lua_tollsd(lua_State* L, int index); +void lua_pushllsd(lua_State* L, const LLSD& data); + +/** + * RAII class to manage the lifespan of a lua_State + */ +class LuaState +{ +public: + typedef std::function<void(std::string msg)> script_finished_fn; + + LuaState(const std::string_view& desc, script_finished_fn cb); + + LuaState(const LuaState&) = delete; + LuaState& operator=(const LuaState&) = delete; + + ~LuaState(); + + bool checkLua(int r); + + operator lua_State*() const { return mState; } + +private: + std::string mDesc; + script_finished_fn mCallback; + lua_State* mState; + std::string mError; +}; + +/** + * LuaPopper is an RAII struct whose role is to pop some number of entries + * from the Lua stack if the calling function exits early. + */ +struct LuaPopper +{ + LuaPopper(lua_State* L, int count): + mState(L), + mCount(count) + {} + + LuaPopper(const LuaPopper&) = delete; + LuaPopper& operator=(const LuaPopper&) = delete; + + ~LuaPopper(); + + void disarm() { set(0); } + void set(int count) { mCount = count; } + + lua_State* mState; + int mCount; +}; + +/** + * LuaFunction is a base class containing a static registry of its static + * subclass call() methods. call() is NOT virtual: instead, each subclass + * constructor passes a pointer to its distinct call() method to the base- + * class constructor, along with a name by which to register that method. + * + * The init() method walks the registry and registers each such name with the + * passed lua_State. + */ +class LuaFunction +{ +public: + LuaFunction(const std::string_view& name, lua_CFunction function); + + static void init(lua_State* L); + + static lua_CFunction get(const std::string& key); + +private: + using Registry = std::map<std::string, lua_CFunction>; + static Registry& getRegistry(); +}; + +/** + * lua_function(name) is a macro to facilitate defining C++ functions + * available to Lua. It defines a subclass of LuaFunction and declares a + * static instance of that subclass, thereby forcing the compiler to call its + * constructor at module initialization time. The constructor passes the + * stringized instance name to its LuaFunction base-class constructor, along + * with a pointer to the static subclass call() method. It then emits the + * call() method definition header, to be followed by a method body enclosed + * in curly braces as usual. + */ +#define lua_function(name) \ +static struct name##_ : public LuaFunction \ +{ \ + name##_(): LuaFunction(#name, &call) {} \ + static int call(lua_State* L); \ +} name; \ +int name##_::call(lua_State* L) +// { +// ... supply method body here, referencing 'L' ... +// } + +// Usage: std::cout << lua_what(L, stackindex) << ...; +// Reports on the Lua value found at the passed stackindex. +// If cast to std::string, returns the corresponding string value. +class lua_what +{ +public: + lua_what(lua_State* state, int idx): + L(state), + index(idx) + {} + + friend std::ostream& operator<<(std::ostream& out, const lua_what& self); + + operator std::string() const { return stringize(*this); } + +private: + lua_State* L; + int index; +}; + +// Usage: std::cout << lua_stack(L) << ...; +// Reports on the contents of the Lua stack. +// If cast to std::string, returns the corresponding string value. +class lua_stack +{ +public: + lua_stack(lua_State* state): + L(state) + {} + + friend std::ostream& operator<<(std::ostream& out, const lua_stack& self); + + operator std::string() const { return stringize(*this); } + +private: + lua_State* L; +}; + +// log exit from any block declaring an instance of DebugExit, regardless of +// how control leaves that block +struct DebugExit +{ + DebugExit(const std::string& name): mName(name) {} + DebugExit(const DebugExit&) = delete; + DebugExit& operator=(const DebugExit&) = delete; + ~DebugExit(); + + std::string mName; +}; + +#endif /* ! defined(LL_LUA_FUNCTION_H) */ diff --git a/indra/llcommon/lualistener.cpp b/indra/llcommon/lualistener.cpp new file mode 100644 index 0000000000..0fa03ffb3b --- /dev/null +++ b/indra/llcommon/lualistener.cpp @@ -0,0 +1,103 @@ +/** + * @file lualistener.cpp + * @author Nat Goodspeed + * @date 2024-02-06 + * @brief Implementation for lualistener. + * + * $LicenseInfo:firstyear=2024&license=viewerlgpl$ + * Copyright (c) 2024, Linden Research, Inc. + * $/LicenseInfo$ + */ + +// Precompiled header +#include "linden_common.h" +// associated header +#include "lualistener.h" +// STL headers +// std headers +#include <cstdlib> // std::rand() +#include <cstring> // std::memcpy() +// external library headers +#include "luau/lua.h" +// other Linden headers +#include "llerror.h" +#include "llleaplistener.h" +#include "lua_function.h" + +LuaListener::LuaListener(lua_State* L): + super(getUniqueKey()), + mListener( + new LLLeapListener( + [L](LLEventPump& pump, const std::string& listener) + { return connect(L, pump, listener); })) +{ + mReplyConnection = connect(L, mReplyPump, "LuaListener"); +} + +LuaListener::~LuaListener() +{ + LL_DEBUGS("Lua") << "~LuaListener('" << mReplyPump.getName() << "')" << LL_ENDL; +} + +int LuaListener::getUniqueKey() +{ + // Find a random key that does NOT already correspond to a LuaListener + // instance. Passing a duplicate key to LLInstanceTracker would do Bad + // Things. + int key; + do + { + key = std::rand(); + } while (LuaListener::getInstance(key)); + // This is theoretically racy, if we were instantiating new + // LuaListeners on multiple threads. Don't. + return key; +} + +LLBoundListener LuaListener::connect(lua_State* L, LLEventPump& pump, const std::string& listener) +{ + return pump.listen( + listener, + [L, pumpname=pump.getName()](const LLSD& data) + { return call_lua(L, pumpname, data); }); +} + +bool LuaListener::call_lua(lua_State* L, const std::string& pump, const LLSD& data) +{ + LL_INFOS("Lua") << "LuaListener::call_lua('" << pump << "', " << data << ")" << LL_ENDL; + if (! lua_checkstack(L, 3)) + { + LL_WARNS("Lua") << "Cannot extend Lua stack to call listen_events() callback" + << LL_ENDL; + return false; + } + // push the registered Lua callback function stored in our registry as + // "event.function" + lua_getfield(L, LUA_REGISTRYINDEX, "event.function"); + llassert(lua_isfunction(L, -1)); + // pass pump name + lua_pushstdstring(L, pump); + // then the data blob + lua_pushllsd(L, data); + // call the registered Lua listener function; allow it to return bool; + // no message handler + auto status = lua_pcall(L, 2, 1, 0); + bool result{ false }; + if (status != LUA_OK) + { + LL_WARNS("Lua") << "Error in listen_events() callback: " + << lua_tostdstring(L, -1) << LL_ENDL; + } + else + { + result = lua_toboolean(L, -1); + } + // discard either the error message or the bool return value + lua_pop(L, 1); + return result; +} + +std::string LuaListener::getCommandName() const +{ + return mListener->getPumpName(); +} diff --git a/indra/llcommon/lualistener.h b/indra/llcommon/lualistener.h new file mode 100644 index 0000000000..550f029158 --- /dev/null +++ b/indra/llcommon/lualistener.h @@ -0,0 +1,77 @@ +/** + * @file lualistener.h + * @author Nat Goodspeed + * @date 2024-02-06 + * @brief Define LuaListener class + * + * $LicenseInfo:firstyear=2024&license=viewerlgpl$ + * Copyright (c) 2024, Linden Research, Inc. + * $/LicenseInfo$ + */ + +#if ! defined(LL_LUALISTENER_H) +#define LL_LUALISTENER_H + +#include "llevents.h" +#include "llinstancetracker.h" +#include "lluuid.h" +#include <memory> // std::unique_ptr + +#ifdef LL_TEST +#include "lleventfilter.h" +#endif + +class lua_State; +class LLLeapListener; + +/** + * LuaListener is based on LLLeap. It serves an analogous function. + * + * Each LuaListener instance has an int key, generated randomly to + * inconvenience malicious Lua scripts wanting to mess with others. The idea + * is that a given lua_State stores in its Registry: + * - "event.listener": the int key of the corresponding LuaListener, if any + * - "event.function": the Lua function to be called with incoming events + * The original thought was that LuaListener would itself store the Lua + * function -- but surprisingly, there is no C/C++ type in the API that stores + * a Lua function. + * + * (We considered storing in "event.listener" the LuaListener pointer itself + * as a light userdata, but the problem would be if Lua code overwrote that. + * We want to prevent any Lua script from crashing the viewer, intentionally + * or otherwise. Safer to use a key lookup.) + * + * Like LLLeap, each LuaListener instance also has an associated + * LLLeapListener to respond to LLEventPump management commands. + */ +class LuaListener: public LLInstanceTracker<LuaListener, int> +{ + using super = LLInstanceTracker<LuaListener, int>; +public: + LuaListener(lua_State* L); + + LuaListener(const LuaListener&) = delete; + LuaListener& operator=(const LuaListener&) = delete; + + ~LuaListener(); + + std::string getReplyName() const { return mReplyPump.getName(); } + std::string getCommandName() const; + +private: + static int getUniqueKey(); + + static LLBoundListener connect(lua_State* L, LLEventPump& pump, const std::string& listener); + + static bool call_lua(lua_State* L, const std::string& pump, const LLSD& data); + +#ifndef LL_TEST + LLEventStream mReplyPump{ LLUUID::generateNewID().asString() }; +#else + LLEventLogProxyFor<LLEventStream> mReplyPump{ "luapump", false }; +#endif + LLTempBoundListener mReplyConnection; + std::unique_ptr<LLLeapListener> mListener; +}; + +#endif /* ! defined(LL_LUALISTENER_H) */ |