Kernel: Improve "out of memory" error handling

It can now boot with fairly low memory while not crashing and instead
gracefully failing the operation. Userland still does not properly
handle errors.

2 files changed, 3 insertions, 5 deletions

diff --git a/userland/libgui/libgui.c b/userland/libgui/libgui.c
index f7a8079..07edbdd 100644
--- a/userland/libgui/libgui.c
+++ b/userland/libgui/libgui.c
@@ -308,10 +308,7 @@ GUI_Window *GUI_CreateWindow(uint32_t x, uint32_t y, uint32_t sx, uint32_t sy) {
   ftruncate(w->bitmap_fd, MAX_WINDOW_SIZE * sizeof(uint32_t));
   void *rc =
       mmap(NULL, MAX_WINDOW_SIZE * sizeof(uint32_t), 0, 0, w->bitmap_fd, 0);
-  if (!((int)rc >= 0)) {
-    printf("rc: %x\n", rc);
-    assert(0);
-  }
+  assert(rc != (void *)(-1));
   w->bitmap_ptr = rc;
 
   // Send the request to the windowserver
diff --git a/userland/windowserver/ws.c b/userland/windowserver/ws.c
index 6d01048..11efa59 100644
--- a/userland/windowserver/ws.c
+++ b/userland/windowserver/ws.c
@@ -103,6 +103,7 @@ void setup_display(DISPLAY *disp, const char *path, uint64_t size) {
       ;
   }
   disp->true_buffer = mmap(NULL, size, 0, 0, disp->vga_fd, 0);
+  assert(disp->true_buffer != (void *)(-1));
   disp->back_buffer = malloc(size + 0x1000);
   disp->window = window;
 
@@ -110,7 +111,7 @@ void setup_display(DISPLAY *disp, const char *path, uint64_t size) {
   assert(disp->wallpaper_fd >= 0);
   ftruncate(disp->wallpaper_fd, size);
   void *rc = mmap(NULL, size, 0, 0, disp->wallpaper_fd, 0);
-  assert(rc);
+  assert(rc != (void *)(-1));
   disp->wallpaper_buffer = rc;
   for (int i = 0; i < disp->size / disp->bpp; i++) {
     uint32_t *p = disp->wallpaper_buffer + i * sizeof(uint32_t);