AP_Scripting: Add support for REPL over MAVLink

libraries/AP_Scripting/lua_scripts.cpp

@@ -33,9 +33,10 @@ extern const AP_HAL::HAL& hal;
 bool lua_scripts::overtime;
 jmp_buf lua_scripts::panic_jmp;
 
-lua_scripts::lua_scripts(const AP_Int32 &vm_steps, const AP_Int32 &heap_size, const AP_Int8 &debug_level)
+lua_scripts::lua_scripts(const AP_Int32 &vm_steps, const AP_Int32 &heap_size, const AP_Int8 &debug_level, struct AP_Scripting::terminal_s &_terminal)
     : _vm_steps(vm_steps),
-      _debug_level(debug_level) {
+      _debug_level(debug_level),
+     terminal(_terminal) {
     _heap = hal.util->allocate_heap_memory(heap_size);
 }
 
@@ -52,6 +53,7 @@ void lua_scripts::hook(lua_State *L, lua_Debug *ar) {
 int lua_scripts::atpanic(lua_State *L) {
     gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: Panic: %s", lua_tostring(L, -1));
     hal.console->printf("Lua: Panic: %s\n", lua_tostring(L, -1));
+    printf("Lua: Panic: %s\n", lua_tostring(L, -1));
     longjmp(panic_jmp, 1);
     return 0;
 }
@@ -91,8 +93,16 @@ lua_scripts::script_info *lua_scripts::load_script(lua_State *L, char *filename)
     new_script->name = filename;
     new_script->next = nullptr;
 
+    create_sandbox(L);
+    lua_setupvalue(L, -2, 1);
 
-    // find and create a sandbox for the new chunk
+    new_script->lua_ref = luaL_ref(L, LUA_REGISTRYINDEX);   // cache the reference
+    new_script->next_run_ms = AP_HAL::millis64() - 1; // force the script to be stale
+
+    return new_script;
+}
+
+void lua_scripts::create_sandbox(lua_State *L) {
     lua_newtable(L);
     luaopen_base_sandbox(L);
     lua_pushstring(L, "math");
@@ -112,12 +122,7 @@ lua_scripts::script_info *lua_scripts::load_script(lua_State *L, char *filename)
     lua_settable(L, -3);
     load_lua_bindings(L);
     load_generated_sandbox(L);
-    lua_setupvalue(L, -2, 1);
 
-    new_script->lua_ref = luaL_ref(L, LUA_REGISTRYINDEX);   // cache the reference
-    new_script->next_run_ms = AP_HAL::millis64() - 1; // force the script to be stale
-
-    return new_script;
 }
 
 void lua_scripts::load_all_scripts_in_dir(lua_State *L, const char *dirname) {
@@ -164,6 +169,13 @@ void lua_scripts::load_all_scripts_in_dir(lua_State *L, const char *dirname) {
     AP::FS().closedir(d);
 }
 
+void lua_scripts::reset_loop_overtime(lua_State *L) {
+    overtime = false;
+    // reset the hook to clear the counter
+    const int32_t vm_steps = MAX(_vm_steps, 1000);
+    lua_sethook(L, hook, LUA_MASKCOUNT, vm_steps);
+}
+
 void lua_scripts::run_next_script(lua_State *L) {
     if (scripts == nullptr) {
 #if defined(AP_SCRIPTING_CHECKS) && AP_SCRIPTING_CHECKS >= 1
@@ -172,16 +184,12 @@ void lua_scripts::run_next_script(lua_State *L) {
         return;
     }
 
-    // reset the current script tracking information
-    overtime = false;
-
     // strip the selected script out of the list
     script_info *script = scripts;
     scripts = script->next;
 
     // reset the hook to clear the counter
-    const int32_t vm_steps = MAX(_vm_steps, 1000);
-    lua_sethook(L, hook, LUA_MASKCOUNT, vm_steps);
+    reset_loop_overtime(L);
 
     // store top of stack so we can calculate the number of return values
     int stack_top = lua_gettop(L);
@@ -192,7 +200,7 @@ void lua_scripts::run_next_script(lua_State *L) {
     if(lua_pcall(L, 0, LUA_MULTRET, 0)) {
         if (overtime) {
             // script has consumed an excessive amount of CPU time
-            gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: %s exceeded time limit (%d)", script->name,  (int)vm_steps);
+            gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: %s exceeded time limit", script->name);
             remove_script(L, script);
         } else {
             hal.console->printf("Lua: Error: %s\n", lua_tostring(L, -1));
@@ -314,6 +322,19 @@ void *lua_scripts::alloc(void *ud, void *ptr, size_t osize, size_t nsize) {
     return hal.util->heap_realloc(_heap, ptr, nsize);
 }
 
+void lua_scripts::repl_cleanup (void) {
+    if (terminal.session) {
+        terminal.session = false;
+        if (terminal.output_fd != -1) {
+            AP::FS().close(terminal.output_fd);
+            terminal.output_fd = -1;
+            AP::FS().unlink(REPL_DIRECTORY "/in");
+            AP::FS().unlink(REPL_DIRECTORY "/out");
+            AP::FS().unlink(REPL_DIRECTORY);
+        }
+    }
+}
+
 void lua_scripts::run(void) {
     bool succeeded_initial_load = false;
 
@@ -336,6 +357,8 @@ void lua_scripts::run(void) {
         }
         scripts = nullptr;
         overtime = false;
+        // end any open REPL sessions
+        repl_cleanup();
     }
 
     lua_state = lua_newstate(alloc, NULL);
@@ -355,6 +378,12 @@ void lua_scripts::run(void) {
     succeeded_initial_load = true;
 
     while (AP_Scripting::get_singleton()->enabled()) {
+        // handle terminal data if we have any
+        if (terminal.session) {
+            doREPL(L);
+            continue;
+        }
+
 #if defined(AP_SCRIPTING_CHECKS) && AP_SCRIPTING_CHECKS >= 1
         if (lua_gettop(L) != 0) {
             AP_HAL::panic("Lua: Stack should be empty before running scripts");