3 files changed, 64 insertions, 55 deletions

diff --git a/src/kernel/paging.c b/src/kernel/paging.c
index 4672788..0432ab6 100644
--- a/src/kernel/paging.c
+++ b/src/kernel/paging.c
@@ -132,7 +132,8 @@ void init_paging() {
 
 __attribute__ ((pure))
 void *vma_to_pma(void *pd, const void *vma) {
-  return (void *)(((uint32_t *)(((uint32_t *)pd)[(uint32_t)vma >> 22] & PE_ADDR_MASK))[((uint32_t)vma >> 12) % 1024] & PE_ADDR_MASK) + (uint32_t)vma % 4096;
+  //this is maybe not good - in the case where pd is zero, vma is returned unconsted. hopefully this doesn't become a problem.
+  return pd ? (void *)(((uint32_t *)(((uint32_t *)pd)[(uint32_t)vma >> 22] & PE_ADDR_MASK))[((uint32_t)vma >> 12) % 1024] & PE_ADDR_MASK) + (uint32_t)vma % 4096 : (void *)(uint32_t)vma;
 }
 
 void switch_to_kernel_cr3() {
@@ -143,7 +144,8 @@ void switch_to_kernel_cr3() {
 }
 
 void switch_to_task_cr3() {
-  asm volatile (
-    "mov %0, %%cr3"
-  : : "a" (active_task->page_directory));
+  if (active_task->page_directory)
+    asm volatile (
+      "mov %0, %%cr3"
+    : : "a" (active_task->page_directory));
 }
\ No newline at end of file
diff --git a/src/kernel/task.c b/src/kernel/task.c
index e2412e1..8d8de86 100644
--- a/src/kernel/task.c
+++ b/src/kernel/task.c
@@ -86,12 +86,12 @@ void advance_active_task() {
 }
 
 void make_sure_tasks() {
-  for (uint8_t n = 0; n < MAX_TASKS; ++n)
-    if (tasks[n].page_directory)
-      return;
-  logf(LOG_INFO, "No tasks, halting.");
-  while (1)
-    asm("hlt");
+  while (1) {
+    for (uint8_t n = 0; n < MAX_TASKS; ++n)
+      if (tasks[n].page_directory)
+        return;
+    tmp_halt();
+  }
 }
 
 //IPC stuff isn't fully implemented, or tested in this version.
diff --git a/src/kernel/window.c b/src/kernel/window.c
index c251077..74273fb 100644
--- a/src/kernel/window.c
+++ b/src/kernel/window.c
@@ -289,63 +289,70 @@ void on_action(struct window_action packet) {
   if (packet.action_type == NOT_READY)
     return;
 
-  if (top_window) {
-    if (packet.action_type == KEY_DOWN)
-      for (uint8_t i = 0; i < N_WM_ACTIONS; ++i)
-        if (fuzzy_key_match(keybinds[i], packet.as_key)) {
-          switch_to_kernel_cr3();
-          struct window *old_top, *old_bottom;
-          switch (i) {
-          case WM_SHUFFLE_UP:
-            if (!top_window->below)
-              break;
-            old_top = top_window;
-            old_bottom = bottom_window;
-            top_window = old_top->below;
-            top_window->above = 0;
-            old_top->below = 0;
-            old_top->above = old_bottom;
-            old_bottom->below = old_top;
-            bottom_window = old_top;
-            paint_and_above(bottom_window->above);
+  if (packet.action_type == KEY_DOWN)
+    for (uint8_t i = 0; i < N_WM_ACTIONS; ++i)
+      if (fuzzy_key_match(keybinds[i], packet.as_key)) {
+        switch_to_kernel_cr3();
+        struct window *old_top, *old_bottom;
+        switch (i) {
+        case WM_SHUFFLE_UP:
+          if (!top_window || !top_window->below)
             break;
-          case WM_SHUFFLE_DOWN:
-            if (!top_window->below)
-              break;
-            old_top = top_window;
-            old_bottom = bottom_window;
-            bottom_window = old_bottom->above;
-            bottom_window->below = 0;
-            old_bottom->above = 0;
-            old_bottom->below = old_top;
-            old_top->above = old_bottom;
-            top_window = old_bottom;
-            paint_and_above(top_window);
+          old_top = top_window;
+          old_bottom = bottom_window;
+          top_window = old_top->below;
+          top_window->above = 0;
+          old_top->below = 0;
+          old_top->above = old_bottom;
+          old_bottom->below = old_top;
+          bottom_window = old_top;
+          paint_and_above(bottom_window->above);
+          break;
+        case WM_SHUFFLE_DOWN:
+          if (!top_window || !top_window->below)
             break;
-          case WM_MOVE_LEFT:
+          old_top = top_window;
+          old_bottom = bottom_window;
+          bottom_window = old_bottom->above;
+          bottom_window->below = 0;
+          old_bottom->above = 0;
+          old_bottom->below = old_top;
+          old_top->above = old_bottom;
+          top_window = old_bottom;
+          paint_and_above(top_window);
+          break;
+        case WM_MOVE_LEFT:
+          if (top_window) {
             --top_window->xpos;
             paint_all();
-            break;
-          case WM_MOVE_RIGHT:
+          }
+          break;
+        case WM_MOVE_RIGHT:
+          if (top_window) {
             ++top_window->xpos;
             paint_all();
-            break;
-          case WM_MOVE_UP:
+          }
+          break;
+        case WM_MOVE_UP:
+          if (top_window) {
             --top_window->ypos;
             paint_all();
-            break;
-          case WM_MOVE_DOWN:
+          }
+          break;
+        case WM_MOVE_DOWN:
+          if (top_window) {
             ++top_window->ypos;
             paint_all();
-            break;
-          case WM_RUN_COMMAND:
-            if (!try_elf_run(drives, run_command, run_command_pass, 0))
-              PANIC("Couldn't run program listed in " RUN_COMMAND_FILE ".");
           }
-          switch_to_task_cr3();
-          return;
+          break;
+        case WM_RUN_COMMAND:
+          if (!try_elf_run(drives, run_command, run_command_pass, 0))
+            PANIC("Couldn't run program listed in " RUN_COMMAND_FILE ".");
         }
+        switch_to_task_cr3();
+        return;
+      }
 
+  if (top_window)
     send_action(top_window, packet);
-  }
 }
\ No newline at end of file