adding the embedded Python init/terminate code

src/Makefile

@@ -1,17 +1,21 @@
-OBJS=main.o sysinput.o fbinit.o fbprimitive.o log.o gpio.o msg_queue.o time_func.o config.o splash.o
-LIBS=-lbcm2835 -lpthread
-CFLAGS=-g -O -DDEBUG_ASSERT
+OBJS=main.o sysinput.o ep_init.o ep_util.o fbinit.o fbprimitive.o log.o gpio.o msg_queue.o \
+     time_func.o config.o splash.o
+LIBS=-lpython3.7m -lcrypt -lbcm2835 -lpthread -ldl -lutil -lm
+CFLAGS=-I/usr/include/python3.7m -Wall -fstack-protector -fwrapv -fno-PIE -g -O3 -DDEBUG_ASSERT
+LDFLAGS=-L/usr/lib/python3.7/config-3.7m-arm-linux-gnueabihf -Xlinker -export-dynamic -Wl,-O1 \
+        -Wl,-Bsymbolic-functions
 
 all: upiwin
 
 upiwin: $(OBJS)
-	gcc -o upiwin $(OBJS) $(LIBS)
+	gcc -o upiwin $(LDFLAGS) $(OBJS) $(LIBS)
 
 .c.o:
 	gcc -c $(CFLAGS) $<
 
 splash.o: splash.bin
-	objcopy -I binary -O elf32-littlearm -B arm --rename-section .data=.rodata,alloc,load,readonly,data,contents splash.bin splash.o
+	objcopy -I binary -O elf32-littlearm -B arm --rename-section \
+		.data=.rodata,alloc,load,readonly,data,contents splash.bin splash.o
 
 splash.bin: splash.png ../buildutils/mksplash
 	../buildutils/mksplash splash.png splash.bin

src/config.c

@@ -66,6 +66,7 @@ static void init_defaults(void)
   memset(&Gconfig, 0, sizeof(GLOBAL_CONFIG));
   Gconfig.framebuffer_device = "/dev/fb1";
   Gconfig.touchscreen_device = "/dev/input/touchscreen";
+  Gconfig.python_loc = "/usr/bin/python3";
   Gconfig.button_debounce = 100;
   Gconfig.sys_mq_length = 64;
 }

src/config.h

@@ -9,6 +9,7 @@ typedef void (*PEXITFUNC)(void);
 typedef struct tagGLOBAL_CONFIG {
   PCSTR framebuffer_device;    /* name of frame buffer device */
   PCSTR touchscreen_device;    /* name of touchscreen device */
+  PCSTR python_loc;            /* location of the Python3 executable */
   UINT32 button_debounce;      /* minimum time between button up and next button down (ms) */
   UINT32 sys_mq_length;        /* length of system message queue */
 } GLOBAL_CONFIG;

src/ep_init.c

@@ -0,0 +1,104 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include "scode.h"
+#include "config.h"
+#include "log.h"
+#include "ep_init.h"
+#include "ep_util.h"
+
+PCSTR Mod_UPIWIN = "upiwin";              /* name of the primary UPIWIN module */
+PCSTR Mod_UPIWIN_tmp = "upiwin_tmp";      /* name of the temporary UPIWIN module */
+
+static wchar_t *python_name = NULL;       /* location of the Python executable */
+
+static PyObject *upiwin_module = NULL;
+static PyObject *upiwin_tmp_module = NULL;
+
+static PyObject *init_upiwin_module(void)
+{
+}
+
+static PyObject *init_upiwin_tmp_module(void)
+{
+}
+
+/* used to link the two modules into Python's init table */
+static struct _inittab upiwin_inittab[] = {
+  { Mod_UPIWIN,     init_upiwin_module     },
+  { Mod_UPIWIN_tmp, init_upiwin_tmp_module },
+  { NULL,           NULL                   }
+};
+
+static void epython_cleanup(void)
+{
+  Py_DECREF(upiwin_tmp_module);
+  upiwin_tmp_module = NULL;
+  Py_DECREF(upiwin_module);
+  upiwin_module = NULL;
+  if (!Py_FinalizeEx())
+    Log(LWARN, "errors encountered when Python uninitialized itself");
+  PyMem_RawFree(python_name);
+  python_name = NULL;
+}
+
+HRESULT Epython_setup(void)
+{
+  HRESULT hr;
+  size_t size;
+
+  python_name = Py_DecodeLocale(Gconfig.python_loc, &size);
+  if (!python_name)
+  {
+    if (size==(size_t)(-1))
+    {
+      Log(LFATAL, "error allocating Python program location");
+      return E_OUTOFMEMORY;
+    }
+    else
+    {
+      Log(LFATAL, "internal error in Py_DecodeLocale");
+      return E_UNEXPECTED;
+    }
+  }
+  Py_SetProgramName(python_name);
+
+  if (PyImport_ExtendInittab(upiwin_inittab))
+  {
+    Log(LFATAL, "error allocating extended init table");
+    hr = E_OUTOFMEMORY;
+    goto error_0;
+  }
+
+  Py_Initialize();
+
+  /* Import the modules */
+  upiwin_module = PyImport_ImportModule(Mod_UPIWIN);
+  if (!upiwin_module)
+  {
+    Log(LFATAL, "error importing the upiwin module");
+    hr = Epython_trace_exception();
+    goto error_1;
+  }
+  upiwin_tmp_module = PyImport_ImportModule(Mod_UPIWIN_tmp);
+  if (!upiwin_tmp_module)
+  {
+    Log(LFATAL, "error importing the upiwin_tmp module");
+    hr = Epython_trace_exception();
+    goto error_2;
+  }
+
+  hr = Config_exitfunc(epython_cleanup);
+  if (FAILED(hr))
+    epython_cleanup();
+  return hr;
+
+error_2:
+  Py_DECREF(upiwin_module);
+  upiwin_module = NULL;
+error_1:
+  Py_FinalizeEx();
+error_0:
+  PyMem_RawFree(python_name);
+  python_name = NULL;
+  return hr;
+}

src/ep_init.h

@@ -0,0 +1,11 @@
+#ifndef __EP_INIT_H_INCLUDED
+#define __EP_INIT_H_INCLUDED
+
+#include "wintype.h"
+
+extern PCSTR Mod_UPIWIN;
+extern PCSTR Mod_UPIWIN_tmp;
+
+extern HRESULT Epython_setup(void);
+
+#endif /* __EP_INIT_H_INCLUDED */

src/ep_util.c

@@ -0,0 +1,44 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include "scode.h"
+#include "ep_util.h"
+#include "log.h"
+
+void Epython_log_object(int level, const char *label, PyObject *object)
+{
+  BOOL traced = FALSE;
+  PyObject *repr;
+  PCSTR pstr;
+
+  repr = PyObject_Repr(object);
+  if (repr)
+  {
+    ASSERT(PyUnicode_Check(repr));
+    pstr = PyUnicode_AsUTF8(repr);
+    Log(level, "object %s: %s", label, pstr);
+    traced = TRUE;
+    Py_DECREF(repr);
+  }
+
+  if (!traced)
+    Log(level, "object %s: could not be logged (memory error)", label);
+}
+
+HRESULT Epython_trace_exception(void)
+{
+  HRESULT hr = E_FAIL;
+  
+  PyObject *type, *value, *traceback;
+  PyErr_Fetch(&type, &value, &traceback);
+  if (!type)
+    return S_OK;
+
+  Epython_log_object(LERROR, "exception type", type);
+  Epython_log_object(LERROR, "exception value", value);
+  Epython_log_object(LERROR, "exception traceback", value);
+
+  Py_DECREF(type);
+  Py_DECREF(value);
+  Py_DECREF(traceback);
+  return hr;
+}

src/ep_util.h

@@ -0,0 +1,11 @@
+#ifndef __EP_UTIL_H_INCLUDED
+#define __EP_UTIL_H_INCLUDED
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include "wintype.h"
+
+extern void Epython_log_object(int level, const char *label, PyObject *object);
+extern HRESULT Epython_trace_exception(void);
+
+#endif /* __EP_UTIL_H_INCLUDED */

src/main.c

@@ -8,6 +8,7 @@
 #include "fbinit.h"
 #include "fbprimitive.h"
 #include "time_func.h"
+#include "ep_init.h"
 #include "sysinput.h"
 
 static void do_draw(void)
@@ -46,10 +47,12 @@ int main(int argc, char *argv[])
     return EXIT_FAILURE;
   if (FAILED(Gpio_setup()))
     return EXIT_FAILURE;
+  if (FAILED(Epython_setup()))
+    return EXIT_FAILURE;
   if (FAILED(Sys_enable_input()))
     return EXIT_FAILURE;
   Log(LINFO, "Pausing at startup.");
-  sleep(3); /* wait to show off splash screen */
+  sleep(2); /* wait to show off splash screen */
 
   Fb_clear();
   /* temporary drawing here */

src/scode.h

@@ -64,6 +64,6 @@
 #define E_UNEXPECTED                 SCODE_CAST(0x8000FFFF)    /* unexpected error */
 
 /* UPIWIN-specific errorcodes */
-#define UPIWIN_E_OUTOFRANGE          SCODE_CAST(0x80060000)    /* value out of range */
+#define UPIWIN_E_INVALIDSTRING       SCODE_CAST(0x80060000)    /* invalid string (decode error) */
 
 #endif /* __SCODE_H_INCLUDED */