Split pyfb_vinfo into a secure and unsecure version

As in commit 2774517 a deadlock has been fixed caused by the pyfb_vinfo function to get the display resolution, this commit splits this function into two versions: pyfb_vinfo and pyfb_svinfo. The pyfb_svinfo is only for external usage while the other one is for internal usage to get the actual display resolution.

Author: RossAdrian

native/framebuffers.c

@@ -223,7 +223,7 @@ void pyfb_close(uint8_t fbnum) {
     unlock(framebuffers[fbnum].fb_lock);
 }
 
-void pyfb_vinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr) {
+void pyfb_svinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr) {
     // first test if this device number is valid.
     if(fbnum >= MAX_FRAMEBUFFERS) {
         return;
@@ -236,6 +236,10 @@ void pyfb_vinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr) {
     unlock(framebuffers[fbnum].fb_lock);
 }
 
+void __APISTATUS_internal pyfb_vinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr) {
+    memcpy(info_ptr, &framebuffers[fbnum].fb_info.vinfo, sizeof(struct fb_var_screeninfo));
+}
+
 int pyfb_flushBuffer(uint8_t fbnum) {
     // first test if this device number is valid
     if(fbnum >= MAX_FRAMEBUFFERS) {

native/module_pyfb.c

@@ -177,7 +177,7 @@ static PyObject* pyfunc_pyfb_getResolution(PyObject* self, PyObject* args) {
 
     // Else build the tuple of the resolution info and return it
     struct pyfb_videomode_info vinfo;
-    pyfb_vinfo((uint8_t)fbnum_c, &vinfo);
+    pyfb_svinfo((uint8_t)fbnum_c, &vinfo);
 
     // check if valid
     if(vinfo.fb_size_b == 0) {

native/paint.c

@@ -84,9 +84,6 @@ void __APISTATUS_internal pyfb_sdrawLine(uint8_t fbnum,
         return;
     }
 
-    struct pyfb_videomode_info vinfo;
-    pyfb_vinfo(fbnum, &vinfo);
-
     // Ok, then lock
     pyfb_fblock(fbnum);
 
@@ -99,6 +96,8 @@ void __APISTATUS_internal pyfb_sdrawLine(uint8_t fbnum,
     }
 
     // check if all values are valid
+    struct pyfb_videomode_info vinfo;
+    pyfb_vinfo(fbnum, &vinfo);
     unsigned long int xres = vinfo.vinfo.xres;
     unsigned long int yres = vinfo.vinfo.yres;
 

native/pyframebuffer.h

@@ -197,11 +197,27 @@ extern void pyfb_close(uint8_t fbnum);
  * Returns the videomode info of a specific framebuffer. If the framebuffer is not
  * opened, then the @c pyfb_videomode_info.fb_size_b field will be @c 0 . If it is
  * not 0, then the structure is valid and the framebuffer is opened.
+ * 
+ * This is the secure version of pyfb_vinfo as it locks the framebuffer before
+ * collecting the data.
+ *
+ * @param fbnum The framebuffer number to get the infos of
+ * @param info_ptr The pointer to copy the videmode info to
+ */
+extern void pyfb_svinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr);
+
+/**
+ * Returns the videomode info of a specific framebuffer. If the framebuffer is not
+ * opened, then the @c pyfb_videomode_info.fb_size_b field will be @c 0 . If it is
+ * not 0, then the structure is valid and the framebuffer is opened.
+ * 
+ * This is the insecure version of pyfb_vinfo as it not locks the framebuffer before
+ * collecting the data.
  *
  * @param fbnum The framebuffer number to get the infos of
  * @param info_ptr The pointer to copy the videmode info to
  */
-extern void pyfb_vinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr);
+extern void __APISTATUS_internal pyfb_vinfo(uint8_t fbnum, struct pyfb_videomode_info* info_ptr);
 
 /**
  * Paints a single pixel to the framebuffer. This function is secure because before