1 //===-- Lua.cpp -----------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "Lua.h"
10 #include "SWIGLuaBridge.h"
11 #include "lldb/Host/FileSystem.h"
12 #include "lldb/Utility/FileSpec.h"
13 #include "llvm/Support/Error.h"
14 #include "llvm/Support/FormatVariadic.h"
15 
16 using namespace lldb_private;
17 using namespace lldb;
18 
19 static int lldb_print(lua_State *L) {
20   int n = lua_gettop(L);
21   lua_getglobal(L, "io");
22   lua_getfield(L, -1, "stdout");
23   lua_getfield(L, -1, "write");
24   for (int i = 1; i <= n; i++) {
25     lua_pushvalue(L, -1); // write()
26     lua_pushvalue(L, -3); // io.stdout
27     luaL_tolstring(L, i, nullptr);
28     lua_pushstring(L, i != n ? "\t" : "\n");
29     lua_call(L, 3, 0);
30   }
31   return 0;
32 }
33 
34 Lua::Lua() : m_lua_state(luaL_newstate()) {
35   assert(m_lua_state);
36   luaL_openlibs(m_lua_state);
37   luaopen_lldb(m_lua_state);
38   lua_pushcfunction(m_lua_state, lldb_print);
39   lua_setglobal(m_lua_state, "print");
40 }
41 
42 Lua::~Lua() {
43   assert(m_lua_state);
44   lua_close(m_lua_state);
45 }
46 
47 llvm::Error Lua::Run(llvm::StringRef buffer) {
48   int error =
49       luaL_loadbuffer(m_lua_state, buffer.data(), buffer.size(), "buffer") ||
50       lua_pcall(m_lua_state, 0, 0, 0);
51   if (error == LUA_OK)
52     return llvm::Error::success();
53 
54   llvm::Error e = llvm::make_error<llvm::StringError>(
55       llvm::formatv("{0}\n", lua_tostring(m_lua_state, -1)),
56       llvm::inconvertibleErrorCode());
57   // Pop error message from the stack.
58   lua_pop(m_lua_state, 1);
59   return e;
60 }
61 
62 llvm::Error Lua::RegisterBreakpointCallback(void *baton, const char *body) {
63   lua_pushlightuserdata(m_lua_state, baton);
64   const char *fmt_str = "return function(frame, bp_loc, ...) {0} end";
65   std::string func_str = llvm::formatv(fmt_str, body).str();
66   if (luaL_dostring(m_lua_state, func_str.c_str()) != LUA_OK) {
67     llvm::Error e = llvm::make_error<llvm::StringError>(
68         llvm::formatv("{0}", lua_tostring(m_lua_state, -1)),
69         llvm::inconvertibleErrorCode());
70     // Pop error message from the stack.
71     lua_pop(m_lua_state, 2);
72     return e;
73   }
74   lua_settable(m_lua_state, LUA_REGISTRYINDEX);
75   return llvm::Error::success();
76 }
77 
78 llvm::Expected<bool>
79 Lua::CallBreakpointCallback(void *baton, lldb::StackFrameSP stop_frame_sp,
80                             lldb::BreakpointLocationSP bp_loc_sp,
81                             StructuredData::ObjectSP extra_args_sp) {
82 
83   lua_pushlightuserdata(m_lua_state, baton);
84   lua_gettable(m_lua_state, LUA_REGISTRYINDEX);
85   StructuredDataImpl extra_args_impl(std::move(extra_args_sp));
86   return LLDBSwigLuaBreakpointCallbackFunction(m_lua_state, stop_frame_sp,
87                                                bp_loc_sp, extra_args_impl);
88 }
89 
90 llvm::Error Lua::RegisterWatchpointCallback(void *baton, const char *body) {
91   lua_pushlightuserdata(m_lua_state, baton);
92   const char *fmt_str = "return function(frame, wp, ...) {0} end";
93   std::string func_str = llvm::formatv(fmt_str, body).str();
94   if (luaL_dostring(m_lua_state, func_str.c_str()) != LUA_OK) {
95     llvm::Error e = llvm::make_error<llvm::StringError>(
96         llvm::formatv("{0}", lua_tostring(m_lua_state, -1)),
97         llvm::inconvertibleErrorCode());
98     // Pop error message from the stack.
99     lua_pop(m_lua_state, 2);
100     return e;
101   }
102   lua_settable(m_lua_state, LUA_REGISTRYINDEX);
103   return llvm::Error::success();
104 }
105 
106 llvm::Expected<bool>
107 Lua::CallWatchpointCallback(void *baton, lldb::StackFrameSP stop_frame_sp,
108                             lldb::WatchpointSP wp_sp) {
109 
110   lua_pushlightuserdata(m_lua_state, baton);
111   lua_gettable(m_lua_state, LUA_REGISTRYINDEX);
112   return LLDBSwigLuaWatchpointCallbackFunction(m_lua_state, stop_frame_sp,
113                                                wp_sp);
114 }
115 
116 llvm::Error Lua::CheckSyntax(llvm::StringRef buffer) {
117   int error =
118       luaL_loadbuffer(m_lua_state, buffer.data(), buffer.size(), "buffer");
119   if (error == LUA_OK) {
120     // Pop buffer
121     lua_pop(m_lua_state, 1);
122     return llvm::Error::success();
123   }
124 
125   llvm::Error e = llvm::make_error<llvm::StringError>(
126       llvm::formatv("{0}\n", lua_tostring(m_lua_state, -1)),
127       llvm::inconvertibleErrorCode());
128   // Pop error message from the stack.
129   lua_pop(m_lua_state, 1);
130   return e;
131 }
132 
133 llvm::Error Lua::LoadModule(llvm::StringRef filename) {
134   FileSpec file(filename);
135   if (!FileSystem::Instance().Exists(file)) {
136     return llvm::make_error<llvm::StringError>("invalid path",
137                                                llvm::inconvertibleErrorCode());
138   }
139 
140   ConstString module_extension = file.GetFileNameExtension();
141   if (module_extension != ".lua") {
142     return llvm::make_error<llvm::StringError>("invalid extension",
143                                                llvm::inconvertibleErrorCode());
144   }
145 
146   int error = luaL_loadfile(m_lua_state, filename.data()) ||
147               lua_pcall(m_lua_state, 0, 1, 0);
148   if (error != LUA_OK) {
149     llvm::Error e = llvm::make_error<llvm::StringError>(
150         llvm::formatv("{0}\n", lua_tostring(m_lua_state, -1)),
151         llvm::inconvertibleErrorCode());
152     // Pop error message from the stack.
153     lua_pop(m_lua_state, 1);
154     return e;
155   }
156 
157   ConstString module_name = file.GetFileNameStrippingExtension();
158   lua_setglobal(m_lua_state, module_name.GetCString());
159   return llvm::Error::success();
160 }
161 
162 llvm::Error Lua::ChangeIO(FILE *out, FILE *err) {
163   assert(out != nullptr);
164   assert(err != nullptr);
165 
166   lua_getglobal(m_lua_state, "io");
167 
168   lua_getfield(m_lua_state, -1, "stdout");
169   if (luaL_Stream *s = static_cast<luaL_Stream *>(
170           luaL_testudata(m_lua_state, -1, LUA_FILEHANDLE))) {
171     s->f = out;
172     lua_pop(m_lua_state, 1);
173   } else {
174     lua_pop(m_lua_state, 2);
175     return llvm::make_error<llvm::StringError>("could not get stdout",
176                                                llvm::inconvertibleErrorCode());
177   }
178 
179   lua_getfield(m_lua_state, -1, "stderr");
180   if (luaL_Stream *s = static_cast<luaL_Stream *>(
181           luaL_testudata(m_lua_state, -1, LUA_FILEHANDLE))) {
182     s->f = out;
183     lua_pop(m_lua_state, 1);
184   } else {
185     lua_pop(m_lua_state, 2);
186     return llvm::make_error<llvm::StringError>("could not get stderr",
187                                                llvm::inconvertibleErrorCode());
188   }
189 
190   lua_pop(m_lua_state, 1);
191   return llvm::Error::success();
192 }
193