AP_Scripting: Run multiple scripts at once

libraries/AP_Scripting/AP_Scripting.cpp

@@ -16,21 +16,20 @@
 #include <AP_Scripting/AP_Scripting.h>
 #include <AP_HAL/AP_HAL.h>
 #include <GCS_MAVLink/GCS.h>
-#include <AP_ROMFS/AP_ROMFS.h>
 
-#include "lua_bindings.h"
+#include "lua_scripts.h"
 
 // ensure that we have a set of stack sizes, and enforce constraints around it
 // except for the minimum size, these are allowed to be defined by the build system
 #undef SCRIPTING_STACK_MIN_SIZE
-#define SCRIPTING_STACK_MIN_SIZE 2048
+#define SCRIPTING_STACK_MIN_SIZE (8 * 1024)
 
 #if !defined(SCRIPTING_STACK_SIZE)
-  #define SCRIPTING_STACK_SIZE 16384
+  #define SCRIPTING_STACK_SIZE (16 * 1024)
 #endif // !defined(SCRIPTING_STACK_SIZE)
 
 #if !defined(SCRIPTING_STACK_MAX_SIZE)
-  #define SCRIPTING_STACK_MAX_SIZE 16384
+  #define SCRIPTING_STACK_MAX_SIZE (64 * 1024)
 #endif // !defined(SCRIPTING_STACK_MAX_SIZE)
 
 static_assert(SCRIPTING_STACK_SIZE >= SCRIPTING_STACK_MIN_SIZE, "Scripting requires a larger minimum stack size");
@@ -58,7 +57,7 @@ const AP_Param::GroupInfo AP_Scripting::var_info[] = {
     AP_GROUPEND
 };
 
-AP_Scripting::AP_Scripting() {       
+AP_Scripting::AP_Scripting() {
     AP_Param::setup_object_defaults(this, var_info);
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
@@ -76,91 +75,23 @@ bool AP_Scripting::init(void) {
 
     if (!hal.scheduler->thread_create(FUNCTOR_BIND_MEMBER(&AP_Scripting::thread, void),
                                       "Scripting", SCRIPTING_STACK_SIZE, AP_HAL::Scheduler::PRIORITY_SCRIPTING, 0)) {
+        gcs().send_text(MAV_SEVERITY_CRITICAL, "Could not create scripting stack (%d)", SCRIPTING_STACK_SIZE);
         return false;
     }
 
-    _running = true;
     return true;
 }
 
-struct {
-    bool overtime; // script exceeded it's execution slot, and we are bailing out with pcalls
-} current_script;
-
-void hook(lua_State *state, lua_Debug *ar) {
-    gcs().send_text(MAV_SEVERITY_INFO, "got a debug hook");
-
-    current_script.overtime = true;
-
-    // we need to aggressively bail out as we are over time
-    // so we will aggressively trap errors until we clear out
-    lua_sethook(state, hook, LUA_MASKCOUNT, 1);
-
-    luaL_error(state, "Exceeded CPU time");
-}
-
 void AP_Scripting::thread(void) {
-    unsigned int loop = 0;
-    lua_State *state = luaL_newstate();
-    luaL_openlibs(state);
-    load_lua_bindings(state);
-
-    // load the sandbox creation function
-    uint32_t sandbox_size;
-    char *sandbox_data = (char *)AP_ROMFS::find_decompress("sandbox.lua", sandbox_size);
-    if (sandbox_data == nullptr) {
-        gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting: Could not find sandbox");
+    lua_scripts *lua = new lua_scripts(_script_vm_exec_count);
+    if (lua == nullptr) {
+        gcs().send_text(MAV_SEVERITY_CRITICAL, "Unable to allocate scripting memory");
         return;
     }
+    lua->run();
 
-    if (luaL_dostring(state, sandbox_data)) {
-        gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting: Loading sandbox: %s", lua_tostring(state, -1));
-        return;
-    }
-    free(sandbox_data);
-
-    luaL_loadstring(state, "gcs.send_text(string.format(\"math.cos(1 + 2) = %f\", math.cos(1+2)))");
-//    luaL_loadfile(state, "test.lua");
-    lua_getglobal(state, "get_sandbox_env"); // find the sandbox creation function
-    if (lua_pcall(state, 0, LUA_MULTRET, 0)) {
-        gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting: Could not create sandbox: %s", lua_tostring(state, -1));
-        return;
-    }
-    lua_setupvalue(state, -2, 1);
-
-    while (true) {
-        hal.scheduler->delay(1000);
-
-        gcs().send_text(MAV_SEVERITY_INFO, "Scripting Loop: %u", loop++);
-
-        // number of VM instructions to run, enforce a minimum script length, don't cap the upper end
-        const int32_t vm_steps = MAX(_script_vm_exec_count, 1000);
-
-        // reset the current script tracking information
-        memset(&current_script, 0, sizeof(current_script));
-        // always reset the hook in case we bailed out
-        lua_sethook(state, hook, LUA_MASKCOUNT, vm_steps);
-
-        const uint32_t startMem = hal.util->available_memory();
-        const uint32_t loadEnd = AP_HAL::micros();
-        lua_pushvalue(state, -1);
-        if(lua_pcall(state, 0, LUA_MULTRET, 0)) {
-            if (current_script.overtime) {
-                // script has consumed an excessive amount of CPU time
-                // FIXME: Find the chunkname for the error message
-                // FIXME: Remove from future execution/restart?
-                gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: exceeded time limit (%d)",  vm_steps);
-            } else {
-                gcs().send_text(MAV_SEVERITY_INFO, "Lua: %s", lua_tostring(state, -1));
-                hal.console->printf("Lua: %s", lua_tostring(state, -1));
-            }
-            lua_pop(state, 1);
-            continue;
-        }
-        const uint32_t runEnd = AP_HAL::micros();
-        const uint32_t endMem = hal.util->available_memory();
-        gcs().send_text(MAV_SEVERITY_INFO, "Time: %d Memory: %d", runEnd - loadEnd, startMem - endMem);
-    }
+    // only reachable if the lua backend has died for any reason
+    gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting has died");
 }
 
 AP_Scripting *AP_Scripting::_singleton = nullptr;

libraries/AP_Scripting/AP_Scripting.h

@@ -30,16 +30,14 @@ public:
 
     bool init(void);
 
-    bool is_running(void) const { return _running; }
-
     static AP_Scripting * get_singleton(void) { return _singleton; }
 
     static const struct AP_Param::GroupInfo var_info[];
 
 private:
-    void thread(void); // main script execution thread
+    void load_script(const char *filename); // load a script from a file
 
-    bool _running;
+    void thread(void); // main script execution thread
 
     AP_Int8 _enable;
     AP_Int32 _script_vm_exec_count;

libraries/AP_Scripting/lua/src/lua.hpp

@@ -6,4 +6,5 @@ extern "C" {
 #include "lua.h"
 #include "lualib.h"
 #include "lauxlib.h"
+#include "lmem.h"
 }

libraries/AP_Scripting/lua_bindings.cpp

@@ -17,8 +17,8 @@ static const luaL_Reg gcs_functions[] =
 };
 
 int lua_servo_set_output_pwm(lua_State *state) {
-    int servo_function = luaL_checkinteger(state, 1);
-    int output_value = luaL_checknumber(state, 2);
+    int servo_function = luaL_checkinteger(state, -2);
+    int output_value = luaL_checknumber(state, -1);
 
     // range check the output function
     if ((servo_function < SRV_Channel::Aux_servo_function_t::k_scripting1) ||

libraries/AP_Scripting/lua_scripts.cpp

@@ -0,0 +1,264 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "lua_scripts.h"
+#include <AP_HAL/AP_HAL.h>
+#include <GCS_MAVLink/GCS.h>
+#include <AP_ROMFS/AP_ROMFS.h>
+
+extern const AP_HAL::HAL& hal;
+
+bool lua_scripts::overtime;
+
+lua_scripts::lua_scripts(const AP_Int32 &vm_steps)
+    : _vm_steps(vm_steps) {
+      scripts = nullptr;
+}
+
+void lua_scripts::hook(lua_State *L, lua_Debug *ar) {
+    lua_scripts::overtime = true;
+
+    // we need to aggressively bail out as we are over time
+    // so we will aggressively trap errors until we clear out
+    lua_sethook(L, hook, LUA_MASKCOUNT, 1);
+
+    luaL_error(L, "Exceeded CPU time");
+}
+
+lua_scripts::script_info *lua_scripts::load_script(lua_State *L, const char *filename) {
+    if (int error = luaL_loadfile(L, filename)) {
+        switch (error) {
+            case LUA_ERRSYNTAX:
+                gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: Syntax error in %s", filename);
+                return nullptr;
+            case LUA_ERRMEM:
+                gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: Insufficent memory loading %s", filename);
+                return nullptr;
+            default:
+                gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: Unknown error (%d) loading %s", error, filename);
+                return nullptr;
+        }
+    }
+
+    script_info *new_script = (script_info *)luaM_malloc(L, sizeof(script_info));
+    if (new_script == nullptr) {
+        // No memory, shouldn't happen, we even attempted to do a GC
+        gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: Insufficent memory loading %s", filename);
+        lua_pop(L, 1); // we can't use the function we just loaded, so ditch it
+        return nullptr;
+    }
+
+    new_script->name = filename;
+    new_script->next = nullptr;
+
+
+    // find and create a sandbox for the new chunk
+    lua_getglobal(L, "get_sandbox_env");
+    if (lua_pcall(L, 0, LUA_MULTRET, 0)) {
+        gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting: Could not create sandbox: %s", lua_tostring(L, -1));
+        return nullptr;
+    }
+    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::run_next_script(lua_State *L) {
+    if (scripts == nullptr) {
+        #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+        AP_HAL::panic("Lua: Attempted to run a script without any scripts queued");
+        #endif // #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+        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);
+
+    // store top of stack so we can calculate the number of return values
+    int stack_top = lua_gettop(L);
+
+    // pop the function to the top of the stack
+    lua_rawgeti(L, LUA_REGISTRYINDEX, script->lua_ref);
+
+    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,  vm_steps);
+            remove_script(L, script);
+        } else {
+            gcs().send_text(MAV_SEVERITY_INFO, "Lua: %s", lua_tostring(L, -1));
+            hal.console->printf("Lua: Error: %s\n", lua_tostring(L, -1));
+            remove_script(L, script);
+        }
+        lua_pop(L, 1);
+        return;
+    } else {
+        int returned = lua_gettop(L) - stack_top;
+        switch (returned) {
+            case 0:
+                // no time to reschedule so bail out
+                remove_script(L, script);
+                break;
+            case 2:
+                {
+                   // sanity check the return types
+                   if (lua_type(L, -2) != LUA_TNUMBER) {
+                       gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: %s did not return a delay (0x%d)", script->name, lua_type(L, -2));
+                       lua_pop(L, 2);
+                       remove_script(L, script);
+                       return;
+                   }
+                   if (lua_type(L, -1) != LUA_TFUNCTION) {
+                       gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: %s did not return a function (0x%d)", script->name, lua_type(L, -1));
+                       lua_pop(L, 2);
+                       remove_script(L, script);
+                       return;
+                   }
+
+                   // types match the expectations, go ahead and reschedule
+                   int old_ref = script->lua_ref;
+                   script->lua_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+                   luaL_unref(L, LUA_REGISTRYINDEX, old_ref);
+                   script->next_run_ms = AP_HAL::millis64() + (uint64_t)luaL_checknumber(L, -1);
+                   lua_pop(L, 1);
+                   reschedule_script(script);
+                   break;
+                }
+            default:
+                {
+                    gcs().send_text(MAV_SEVERITY_CRITICAL, "Lua: %s returned bad result count (%d)", script->name, returned);
+                    remove_script(L, script);
+                    // pop all the results we got that we didn't expect
+                    lua_pop(L, returned);
+                    break;
+                 }
+         }
+     }
+}
+
+void lua_scripts::remove_script(lua_State *L, script_info *script) {
+    // ensure that the script isn't in the loaded list for any reason
+    if (scripts == nullptr) {
+        // nothing to do, already not in the list
+    } else if (scripts == script) {
+        scripts = script->next;
+    } else {
+        for(script_info * current = scripts; current->next != nullptr; current = current->next) {
+            if (current->next == script) {
+                current->next = script->next;
+                break;
+            }
+        }
+    }
+
+    luaL_unref(L, LUA_REGISTRYINDEX, script->lua_ref);
+    luaM_free(L, script);
+}
+
+void lua_scripts::reschedule_script(script_info *script) {
+    if (script == nullptr) {
+       #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+       AP_HAL::panic("Lua: Attempted to schedule a null pointer");
+       #endif // #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+       return;
+    }
+
+    script->next = nullptr;
+    if (scripts == nullptr) {
+        scripts = script;
+        return;
+    }
+
+    uint64_t next_run_ms = script->next_run_ms;
+
+    if (scripts->next_run_ms > next_run_ms) {
+        script->next = scripts;
+        scripts = script;
+        return;
+    }
+
+    script_info *previous = scripts;
+    while (previous->next != nullptr) {
+        if (previous->next->next_run_ms > next_run_ms) {
+            script->next = previous->next;
+            previous->next = script;
+            return;
+        }
+        previous = previous->next;
+    }
+
+    previous->next = script;
+}
+
+void lua_scripts::run(void) {
+    lua_State *L = luaL_newstate();
+    luaL_openlibs(L);
+    load_lua_bindings(L);
+
+    // load the sandbox creation function
+    uint32_t sandbox_size;
+    char *sandbox_data = (char *)AP_ROMFS::find_decompress("sandbox.lua", sandbox_size);
+    if (sandbox_data == nullptr) {
+        gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting: Could not find sandbox");
+        return;
+    }
+
+    if (luaL_dostring(L, sandbox_data)) {
+        gcs().send_text(MAV_SEVERITY_CRITICAL, "Scripting: Loading sandbox: %s", lua_tostring(L, -1));
+        return;
+    }
+    free(sandbox_data);
+
+    // FIXME: Scan the filesystem in an appropriate manner and autostart scripts
+    // FIXME: This panic's SITL if the file is not found
+    reschedule_script(load_script(L, "test.lua"));
+
+    while (true) {
+        if (scripts != nullptr) {
+            // compute delay time
+            uint64_t now_ms = AP_HAL::millis64();
+            if (now_ms < scripts->next_run_ms) {
+                hal.scheduler->delay(scripts->next_run_ms - now_ms);
+            }
+
+            gcs().send_text(MAV_SEVERITY_DEBUG, "Lua: Running %s", scripts->name);
+
+            const uint32_t startMem = hal.util->available_memory();
+            const uint32_t loadEnd = AP_HAL::micros();
+
+            run_next_script(L);
+
+            const uint32_t runEnd = AP_HAL::micros();
+            const uint32_t endMem = hal.util->available_memory();
+            gcs().send_text(MAV_SEVERITY_DEBUG, "Lua: Time: %d Mem: %d", runEnd - loadEnd, startMem - endMem);
+
+        } else {
+            gcs().send_text(MAV_SEVERITY_DEBUG, "Lua: No scripts to run");
+            hal.scheduler->delay(100);
+        }
+
+    }
+}

libraries/AP_Scripting/lua_scripts.h

@@ -0,0 +1,61 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <AP_Common/AP_Common.h>
+#include <AP_Param/AP_Param.h>
+
+#include "lua_bindings.h"
+
+class lua_scripts
+{
+public:
+    lua_scripts(const AP_Int32 &vm_steps);
+
+    /* Do not allow copies */
+    lua_scripts(const lua_scripts &other) = delete;
+    lua_scripts &operator=(const lua_scripts&) = delete;
+
+    // run scripts, does not return unless an error occured
+    void run(void);
+
+    static bool overtime; // script exceeded it's execution slot, and we are bailing out
+private:
+
+    typedef struct script_info {
+       int lua_ref;          // reference to the loaded script object
+       uint64_t next_run_ms; // time (in milliseconds) the script should next be run at
+       const char *name;     // filename for the script // FIXME: This information should be available from Lua
+       script_info *next;
+    } script_info;
+
+    script_info *load_script(lua_State *L, const char *filename);
+
+    void run_next_script(lua_State *L);
+
+    void remove_script(lua_State *L, script_info *script);
+
+    // reschedule the script for execution. It is assumed the script is not in the list already
+    void reschedule_script(script_info *script);
+
+    script_info *scripts; // linked list of scripts to be run, sorted by next run time (soonest first)
+
+    // hook will be run when CPU time for a script is exceeded
+    // it must be static to be passed to the C API
+    static void hook(lua_State *L, lua_Debug *ar);
+
+    const AP_Int32 & _vm_steps;
+
+};