feat: Growable heap, GUI-by-default run, live sysmon, SUB/SUB default login

Kernel / memory:
- mm/kmalloc.c: fix "Heap: Out of memory" under the GUI. The desktop allocates
  three full-screen 32-bit buffers (~11MB) which overflowed the fixed 16MB pool.
  The heap now starts at 32MB and grows on demand from the PMM (16MB regions),
  with region-safe coalescing (only merges physically adjacent blocks) so growth
  never corrupts across separate PMM allocations. Adds heap_get_grow_count().

Build / run:
- Makefile: merge `run-gui` into `run` so `make run` boots into the graphical
  desktop; add `run-headless` (serial-only via QEMU_CMD), bump guest RAM to
  256M, update .PHONY and help.

Configure:
- scripts/kconfig/menuconfig.py: gate the curses UI behind isatty() on stdin and
  stdout so non-interactive `make configure` stops emitting "nocbreak() returned
  ERR" and falls cleanly through to the non-interactive writer.

GUI / userland:
- gui/gui_apps.c: rebuild the System Monitor from hardcoded values into live
  telemetry -- real heap used/total/free with a colour-shifting bar, a scrolling
  heap-utilisation graph, the grow counter, and real PMM RAM figures.
- lazybox `free`: report how many times the heap has grown.

Auth:
- Default login is now SUB / SUB (Kali-style username==password), seeded first
  as the primary uid-0 account and set as the logged-in user; root kept for
  compatibility. Hardcoded "root" defaults (whoami, su, passwd, ssh, sshd
  session) updated to SUB.

Verified: clean build on x86_64/aarch64/armv8i; GUI boots with 0 OOM/0 panic;
auth engine initialises cleanly; `make configure` fallback is clean.

Co-Authored-By: Claude Opus 4.8 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Fh5z6V7nGPbHvqVG5p4CXX

Makefile

@@ -330,7 +330,7 @@ DEPS = $(C_OBJS:.o=.d) $(CPP_OBJS:.o=.d) $(S_OBJS:.o=.d)
 
 .DEFAULT_GOAL := all
 
-.PHONY: all clean run run-fullscreen debug info configure menuconfig config tui nconfig defconfig x86_64_defconfig aarch64_defconfig armv8_defconfig armv8i_defconfig armv81_defconfig arm32_defconfig qemu help
+.PHONY: all clean run run-headless run-fullscreen run-vnc run-server debug info configure menuconfig config tui nconfig defconfig x86_64_defconfig aarch64_defconfig armv8_defconfig armv8i_defconfig armv81_defconfig arm32_defconfig qemu help
 
 all: $(TARGET)
 
@@ -448,24 +448,29 @@ $(IMAGE): $(BUILD_DIR)/boot/boot.bin $(BUILD_DIR)/boot/stage2.bin $(BUILD_DIR)/k
 # -----------------------------------------------------------------------------
 # Execution & Emulation Targets
 # -----------------------------------------------------------------------------
-run qemu: $(TARGET)
-	$(QEMU_CMD)
-
 # -vga std gives the Bochs VBE adapter the kernel drives. vgamem_mb is raised
 # because a 1280x720 32-bit framebuffer needs more than the 8 MB default.
 QEMU_VGA = -device VGA,vgamem_mb=32
 
-run-gui: $(TARGET)
+# `make run` boots straight into the SUB-OS Graphical Desktop Environment. The
+# guest window scales with zoom-to-fit; pass `nogui`/`text` on the kernel
+# command line for the emergency TTY. Use `make run-headless` for serial only.
+run qemu: $(TARGET)
 ifeq ($(ARCH), x86_64)
-	qemu-system-x86_64 -drive format=raw,file=$(IMAGE) \
+	qemu-system-x86_64 -drive format=raw,file=$(IMAGE) -m 256M \
 		-netdev user,id=net0,hostfwd=tcp::2222-:22,hostfwd=tcp::8080-:80 \
 		-device e1000,netdev=net0 $(QEMU_VGA) -display gtk,zoom-to-fit=on -serial stdio
 else ifneq ($(filter $(ARCH), aarch64 arm64),)
-	qemu-system-aarch64 -M virt -cpu cortex-a57 -m 128M -kernel $(BUILD_DIR)/kernel.elf -device virtio-gpu-pci -serial stdio
+	qemu-system-aarch64 -M virt -cpu cortex-a57 -m 256M -kernel $(BUILD_DIR)/kernel.elf -device virtio-gpu-pci -serial stdio
 else
-	qemu-system-arm -M virt -cpu cortex-a15 -m 128M -kernel $(BUILD_DIR)/kernel.elf -device virtio-gpu-pci -serial stdio
+	qemu-system-arm -M virt -cpu cortex-a15 -m 256M -kernel $(BUILD_DIR)/kernel.elf -device virtio-gpu-pci -serial stdio
 endif
 
+# Headless: no graphical window, kernel console on the serial line only. Boot
+# with `nogui` on the kernel command line to reach the TTY in this mode.
+run-headless: $(TARGET)
+	$(QEMU_CMD)
+
 # Fullscreen without distortion: zoom-to-fit scales the guest while preserving
 # its aspect ratio, letterboxing rather than stretching on a wider panel.
 run-fullscreen: $(TARGET)
@@ -521,7 +526,10 @@ help:
 	@echo "  make aarch64_defconfig- Load AArch64 default configuration"
 	@echo "  make armv8i_defconfig - Load ARMv8i (32-bit ARM) default configuration"
 	@echo "  make all [ARCH=...]   - Compile kernel image for selected architecture"
-	@echo "  make qemu [ARCH=...]  - Boot the compiled kernel in QEMU emulator"
+	@echo "  make run [ARCH=...]   - Boot into the SUB-OS Graphical Desktop in QEMU"
+	@echo "  make run-headless     - Boot in QEMU with serial console only (no window)"
+	@echo "  make run-fullscreen   - Boot the desktop in a full-screen QEMU window"
+	@echo "  make run-vnc          - Boot the desktop and expose it over VNC :0"
 	@echo "  make clean            - Remove all compiled objects and disk images"
 	@echo "  make info             - Display build configuration and source metrics"
 

gui/gui_apps.c

@@ -26,19 +26,41 @@ static int simple_atoi(const char* s) {
 // =================================================================
 // 1. System Performance Monitor App (High-Res 320x240)
 // =================================================================
-static uint8_t g_cpu_history[60] = {
-    12, 15, 18, 22, 30, 25, 20, 35, 45, 50, 42, 38, 55, 60, 48, 52, 35, 30, 25, 20,
-    28, 32, 45, 60, 55, 40, 30, 25, 20, 18, 22, 25, 15, 18, 22, 30, 35, 40, 38, 42,
-    30, 25, 20, 18, 15, 22, 28, 35, 40, 48, 52, 45, 38, 30, 25, 20, 18, 15, 20, 24
-};
+/* Rolling trace of live heap utilisation (percent), newest sample on the right.
+ * Seeded flat and advanced one sample per repaint from real allocator stats. */
+static uint8_t g_heap_history[60];
+static bool    g_heap_history_seeded = false;
+
+static void sysmon_sample_heap(uint8_t pct) {
+    if (!g_heap_history_seeded) {
+        for (int i = 0; i < 60; i++) g_heap_history[i] = pct;
+        g_heap_history_seeded = true;
+        return;
+    }
+    for (int i = 0; i < 59; i++) g_heap_history[i] = g_heap_history[i + 1];
+    g_heap_history[59] = pct;
+}
 
 static void sysmon_paint(gui_window_t* win) {
     int cx = win->x + 12;
     int cy = win->y + GUI_TITLEBAR_HEIGHT + 10;
 
-    gui_gfx_draw_string_16_shadow(cx, cy, "CPU Load History (Real-Time)", GUI_THEME_PRIMARY, GUI_COLOR_BLACK);
-    
-    // CPU Graph Box
+    /* Pull live figures straight from the kernel allocators. */
+    uint64_t heap_used  = (uint64_t)heap_get_used_bytes();
+    uint64_t heap_total = (uint64_t)heap_get_total_bytes();
+    uint64_t heap_free  = (uint64_t)heap_get_free_bytes();
+    uint64_t heap_grows = (uint64_t)heap_get_grow_count();
+    uint32_t heap_pct   = heap_total ? (uint32_t)((heap_used * 100) / heap_total) : 0;
+    if (heap_pct > 100) heap_pct = 100;
+
+    uint64_t ram_free_mb  = (pmm_get_free_pages()  * PMM_PAGE_SIZE) / (1024 * 1024);
+    uint64_t ram_total_mb = pmm_get_usable_memory() / (1024 * 1024);
+
+    sysmon_sample_heap((uint8_t)heap_pct);
+
+    gui_gfx_draw_string_16_shadow(cx, cy, "Heap Utilization History (Live)", GUI_THEME_PRIMARY, GUI_COLOR_BLACK);
+
+    // Heap Graph Box
     int graph_x = cx;
     int graph_y = cy + 20;
     int graph_w = win->width - 24;
@@ -54,31 +76,37 @@ static void sysmon_paint(gui_window_t* win) {
         gui_gfx_draw_line(gx, graph_y + 1, gx, graph_y + graph_h - 2, 0xFF1E293B);
     }
 
-    // Plot Waveform
+    // Plot Waveform from the live heap trace
     for (int i = 0; i < 59 && (i * 5 + 5) < graph_w; i++) {
-        int y1 = graph_y + graph_h - 3 - (g_cpu_history[i] * (graph_h - 6)) / 100;
-        int y2 = graph_y + graph_h - 3 - (g_cpu_history[i + 1] * (graph_h - 6)) / 100;
+        int y1 = graph_y + graph_h - 3 - (g_heap_history[i] * (graph_h - 6)) / 100;
+        int y2 = graph_y + graph_h - 3 - (g_heap_history[i + 1] * (graph_h - 6)) / 100;
         gui_gfx_draw_line(graph_x + 4 + i * 5, y1, graph_x + 4 + (i + 1) * 5, y2, GUI_THEME_SUCCESS);
     }
 
-    // Memory Usage Bar
+    // Heap Usage Bar (real used / total)
+    char buf[80];
     int mem_y = graph_y + graph_h + 12;
-    gui_gfx_draw_string_16(cx, mem_y, "RAM Usage: 24 MB / 128 MB (18% Heap)", GUI_THEME_TEXT_MAIN);
-    
+    snprintf(buf, sizeof(buf), "Heap: %llu / %llu KB (%u%%)",
+             (unsigned long long)(heap_used / 1024),
+             (unsigned long long)(heap_total / 1024), heap_pct);
+    gui_gfx_draw_string_16(cx, mem_y, buf, GUI_THEME_TEXT_MAIN);
+
     int bar_y = mem_y + 20;
     int bar_w = win->width - 24;
     gui_gfx_fill_rect(cx, bar_y, bar_w, 12, GUI_THEME_BG_DARK);
-    gui_gfx_fill_rect(cx, bar_y, (bar_w * 24) / 128, 12, GUI_THEME_ACCENT);
+    gui_gfx_fill_rect(cx, bar_y, (int)((uint64_t)bar_w * heap_pct / 100), 12,
+                      (heap_pct >= 90) ? GUI_THEME_DANGER : GUI_THEME_ACCENT);
     gui_gfx_draw_rect(cx, bar_y, bar_w, 12, GUI_THEME_BORDER);
 
-    // System Telemetry Metrics
-    char buf[64];
+    // System Telemetry Metrics (live)
     cpufreq_stats_t stats = cpufreq_get_stats();
-    snprintf(buf, sizeof(buf), "Clock: %u.%03u GHz | Governor: ondemand",
-             stats.current_khz / 1000000, (stats.current_khz % 1000000) / 1000);
+    snprintf(buf, sizeof(buf), "Clock: %u.%03u GHz | Heap free: %llu KB | Grows: %llu",
+             stats.current_khz / 1000000, (stats.current_khz % 1000000) / 1000,
+             (unsigned long long)(heap_free / 1024), (unsigned long long)heap_grows);
     gui_gfx_draw_string(cx, bar_y + 20, buf, GUI_THEME_TEXT_MUTED);
 
-    snprintf(buf, sizeof(buf), "Core Tasks: 6 Active | VFS Cache: 98.4%% Hit", 0);
+    snprintf(buf, sizeof(buf), "System RAM: %llu MB free / %llu MB usable",
+             (unsigned long long)ram_free_mb, (unsigned long long)ram_total_mb);
     gui_gfx_draw_string(cx, bar_y + 32, buf, GUI_THEME_TEXT_DIM);
 }
 

include/mm/kmalloc.h

@@ -14,6 +14,7 @@ void  kfree(void* ptr);
 size_t heap_get_used_bytes(void);
 size_t heap_get_free_bytes(void);
 size_t heap_get_total_bytes(void);
+size_t heap_get_grow_count(void); // Number of on-demand PMM growth events
 
 static inline size_t kmalloc_get_used(void) { return heap_get_used_bytes(); }
 static inline size_t kmalloc_get_free(void) { return heap_get_free_bytes(); }

mm/kmalloc.c

@@ -5,7 +5,8 @@
 #include <kernel/printk.h>
 
 #define HEAP_MAGIC 0x53554248 // "SUBH"
-#define HEAP_INITIAL_PAGES 4096 // 16 MB initial kernel heap
+#define HEAP_INITIAL_PAGES 8192 // 32 MB initial kernel heap
+#define HEAP_GROW_PAGES    4096 // Grow the heap 16 MB at a time on demand
 
 typedef struct heap_block {
     uint32_t magic;
@@ -18,11 +19,21 @@ typedef struct heap_block {
 #define BLOCK_HEADER_SIZE sizeof(heap_block_t)
 
 static heap_block_t* heap_start = NULL;
+static heap_block_t* heap_tail  = NULL; // last block in address order, for O(1) growth
 static size_t heap_used_bytes = 0;
 static size_t heap_free_bytes = 0;
 static size_t heap_total_bytes = 0;
+static size_t heap_grow_count = 0;
 static spinlock_t heap_lock = SPINLOCK_INIT;
 
+/* Two blocks may only be coalesced when they are physically adjacent. The heap
+ * is made of one or more regions carved from the PMM; a region boundary shows
+ * up as a gap between a block and its list successor, so this guard keeps the
+ * free-list merge from ever spanning two independent PMM allocations. */
+static inline bool blocks_adjacent(heap_block_t* a, heap_block_t* b) {
+    return (heap_block_t*)((uint8_t*)a + BLOCK_HEADER_SIZE + a->size) == b;
+}
+
 void heap_init(void) {
     void* initial_mem = pmm_alloc_pages(HEAP_INITIAL_PAGES);
     if (!initial_mem) {
@@ -31,7 +42,7 @@ void heap_init(void) {
     }
 
     heap_start = (heap_block_t*)initial_mem;
-    heap_total_bytes = HEAP_INITIAL_PAGES * PMM_PAGE_SIZE;
+    heap_total_bytes = (size_t)HEAP_INITIAL_PAGES * PMM_PAGE_SIZE;
 
     heap_start->magic = HEAP_MAGIC;
     heap_start->is_free = true;
@@ -39,10 +50,87 @@ void heap_init(void) {
     heap_start->next = NULL;
     heap_start->prev = NULL;
 
+    heap_tail = heap_start;
     heap_used_bytes = 0;
     heap_free_bytes = heap_start->size;
 }
 
+/* Append a fresh region from the PMM to the tail of the free list. Must be
+ * called with heap_lock held. Returns the new free block, or NULL if the PMM
+ * cannot satisfy a contiguous run large enough for the request. */
+static heap_block_t* heap_grow(size_t need) {
+    size_t need_pages = (need + BLOCK_HEADER_SIZE + PMM_PAGE_SIZE - 1) / PMM_PAGE_SIZE;
+    size_t grow_pages = need_pages > HEAP_GROW_PAGES ? need_pages : HEAP_GROW_PAGES;
+
+    void* mem = pmm_alloc_pages(grow_pages);
+    if (!mem && grow_pages != need_pages) {
+        /* Could not get the generous chunk; fall back to exactly what is needed. */
+        grow_pages = need_pages;
+        mem = pmm_alloc_pages(grow_pages);
+    }
+    if (!mem) {
+        return NULL;
+    }
+
+    heap_block_t* region = (heap_block_t*)mem;
+    region->magic = HEAP_MAGIC;
+    region->is_free = true;
+    region->size = (size_t)grow_pages * PMM_PAGE_SIZE - BLOCK_HEADER_SIZE;
+    region->next = NULL;
+    region->prev = heap_tail;
+
+    if (heap_tail) {
+        heap_tail->next = region;
+    }
+    heap_tail = region;
+    if (!heap_start) {
+        heap_start = region;
+    }
+
+    heap_total_bytes += (size_t)grow_pages * PMM_PAGE_SIZE;
+    heap_free_bytes  += region->size;
+    heap_grow_count++;
+
+    /* A PMM run handed back right after the previous tail is a real neighbour;
+     * fuse it so the heap does not fragment purely from growing. */
+    if (region->prev && region->prev->is_free && blocks_adjacent(region->prev, region)) {
+        heap_block_t* prev = region->prev;
+        prev->size += BLOCK_HEADER_SIZE + region->size;
+        prev->next = region->next; // NULL
+        heap_tail = prev;
+        region = prev;
+    }
+
+    return region;
+}
+
+/* Carve `size` bytes out of a free block, splitting off the remainder. Must be
+ * called with heap_lock held; `curr` must be free and large enough. */
+static void* heap_take(heap_block_t* curr, size_t size) {
+    if (curr->size >= size + BLOCK_HEADER_SIZE + 16) {
+        heap_block_t* new_block = (heap_block_t*)((uint8_t*)curr + BLOCK_HEADER_SIZE + size);
+        new_block->magic = HEAP_MAGIC;
+        new_block->is_free = true;
+        new_block->size = curr->size - size - BLOCK_HEADER_SIZE;
+        new_block->next = curr->next;
+        new_block->prev = curr;
+
+        if (curr->next) {
+            curr->next->prev = new_block;
+        } else {
+            heap_tail = new_block;
+        }
+        curr->next = new_block;
+        curr->size = size;
+    }
+
+    curr->is_free = false;
+    heap_used_bytes += curr->size;
+    heap_free_bytes -= curr->size;
+
+    return (void*)((uint8_t*)curr + BLOCK_HEADER_SIZE);
+}
+
 void* kmalloc(size_t size) {
     if (size == 0) return NULL;
 
@@ -51,44 +139,33 @@ void* kmalloc(size_t size) {
 
     spin_lock(&heap_lock);
 
-    heap_block_t* curr = heap_start;
-    while (curr) {
-        if (curr->magic != HEAP_MAGIC) {
-            printk(KERN_ERR "Heap Corruption detected at %p!\n", curr);
-            spin_unlock(&heap_lock);
-            return NULL;
-        }
-
-        if (curr->is_free && curr->size >= size) {
-            // Check if block can be split
-            if (curr->size >= size + BLOCK_HEADER_SIZE + 16) {
-                heap_block_t* new_block = (heap_block_t*)((uint8_t*)curr + BLOCK_HEADER_SIZE + size);
-                new_block->magic = HEAP_MAGIC;
-                new_block->is_free = true;
-                new_block->size = curr->size - size - BLOCK_HEADER_SIZE;
-                new_block->next = curr->next;
-                new_block->prev = curr;
-
-                if (curr->next) {
-                    curr->next->prev = new_block;
-                }
-                curr->next = new_block;
-                curr->size = size;
+    for (int attempt = 0; attempt < 2; attempt++) {
+        heap_block_t* curr = heap_start;
+        while (curr) {
+            if (curr->magic != HEAP_MAGIC) {
+                printk(KERN_ERR "Heap Corruption detected at %p!\n", curr);
+                spin_unlock(&heap_lock);
+                return NULL;
             }
 
-            curr->is_free = false;
-            heap_used_bytes += curr->size;
-            heap_free_bytes -= curr->size;
+            if (curr->is_free && curr->size >= size) {
+                void* ptr = heap_take(curr, size);
+                spin_unlock(&heap_lock);
+                return ptr;
+            }
 
-            spin_unlock(&heap_lock);
-            return (void*)((uint8_t*)curr + BLOCK_HEADER_SIZE);
+            curr = curr->next;
         }
 
-        curr = curr->next;
+        /* No block fit. Pull a new region from the PMM and try once more. */
+        if (attempt == 0 && heap_grow(size)) {
+            continue;
+        }
+        break;
     }
 
     spin_unlock(&heap_lock);
-    printk(KERN_WARNING "Heap: Out of memory for size %llu bytes!\n", size);
+    printk(KERN_WARNING "Heap: Out of memory for size %llu bytes!\n", (uint64_t)size);
     return NULL;
 }
 
@@ -116,21 +193,27 @@ void kfree(void* ptr) {
     heap_used_bytes -= block->size;
     heap_free_bytes += block->size;
 
-    // Coalesce with next block if free
-    if (block->next && block->next->is_free) {
-        block->size += BLOCK_HEADER_SIZE + block->next->size;
-        block->next = block->next->next;
+    // Coalesce with next block if free AND physically adjacent (same region).
+    if (block->next && block->next->is_free && blocks_adjacent(block, block->next)) {
+        heap_block_t* nxt = block->next;
+        block->size += BLOCK_HEADER_SIZE + nxt->size;
+        block->next = nxt->next;
         if (block->next) {
             block->next->prev = block;
+        } else {
+            heap_tail = block;
         }
     }
 
-    // Coalesce with prev block if free
-    if (block->prev && block->prev->is_free) {
-        block->prev->size += BLOCK_HEADER_SIZE + block->size;
-        block->prev->next = block->next;
+    // Coalesce with prev block if free AND physically adjacent (same region).
+    if (block->prev && block->prev->is_free && blocks_adjacent(block->prev, block)) {
+        heap_block_t* prev = block->prev;
+        prev->size += BLOCK_HEADER_SIZE + block->size;
+        prev->next = block->next;
         if (block->next) {
-            block->next->prev = block->prev;
+            block->next->prev = prev;
+        } else {
+            heap_tail = prev;
         }
     }
 
@@ -151,9 +234,10 @@ void* krealloc(void* ptr, size_t new_size) {
         return ptr;
     }
 
+    size_t old_size = block->size;
     void* new_ptr = kmalloc(new_size);
     if (new_ptr) {
-        memcpy(new_ptr, ptr, block->size);
+        memcpy(new_ptr, ptr, old_size);
         kfree(ptr);
     }
     return new_ptr;
@@ -162,3 +246,4 @@ void* krealloc(void* ptr, size_t new_size) {
 size_t heap_get_used_bytes(void)  { return heap_used_bytes; }
 size_t heap_get_free_bytes(void)  { return heap_free_bytes; }
 size_t heap_get_total_bytes(void) { return heap_total_bytes; }
+size_t heap_get_grow_count(void)  { return heap_grow_count; }

net/ssh.c

@@ -30,7 +30,7 @@ int sshd_start(uint16_t port) {
     ssh_sessions[0].in_use = true;
     ssh_sessions[0].state = SSH_STATE_SHELL_ACTIVE;
     ssh_sessions[0].authenticated = true;
-    strcpy(ssh_sessions[0].username, "root");
+    strcpy(ssh_sessions[0].username, "SUB");
     ssh_sessions[0].client_ip = 0x0A000202; // 10.0.2.2 (QEMU Host Gateway)
     ssh_sessions[0].client_port = 52341;
     ssh_sessions[0].connect_time = pit_get_ticks() / 100;

scripts/kconfig/menuconfig.py

@@ -829,17 +829,26 @@ def main():
             print(f"menuconfig: lxdialog front-end failed ({exc}); "
                   f"falling back to the curses UI.", file=sys.stderr)
 
-    # Fallback to Curses GUI replica
-    try:
-        import curses
-        curses.wrapper(run_curses_gui)
-        print(f"*** Configuration saved to {CONFIG_FILE} and {AUTOCONF_HEADER} ***")
-        return
-    except Exception as exc:
-        print(f"menuconfig: curses UI unavailable ({exc}); "
-              f"writing the current configuration non-interactively.", file=sys.stderr)
+    # Fallback to the curses GUI replica, but only when we genuinely have an
+    # interactive terminal on both ends. Probing curses without a real TTY makes
+    # it fail deep inside the wrapper's teardown (e.g. "nocbreak() returned
+    # ERR"), which looked like a crash; gate on isatty so a piped or CI
+    # invocation drops straight to the non-interactive writer instead.
+    if sys.stdin.isatty() and sys.stdout.isatty():
+        try:
+            import curses
+            curses.wrapper(run_curses_gui)
+            print(f"*** Configuration saved to {CONFIG_FILE} and {AUTOCONF_HEADER} ***")
+            return
+        except Exception as exc:
+            print(f"menuconfig: curses UI unavailable ({exc}); "
+                  f"writing the current configuration non-interactively.", file=sys.stderr)
+    else:
+        print("menuconfig: no interactive terminal detected; "
+              "writing the current configuration non-interactively.", file=sys.stderr)
 
-    # Last resort: no usable TTY at all.
+    # Last resort: no usable TTY at all. Preserve an existing .config if present,
+    # otherwise fall back to the architecture default so the build never stalls.
     cfg = load_config()
     save_config(cfg)
     print(f"*** Configuration written to {CONFIG_FILE} and {AUTOCONF_HEADER} ***")

security/auth.c

@@ -23,11 +23,17 @@ void auth_init(void) {
     user_count = 0;
     current_uid = 0;
 
-    // Seed default users
-    auth_add_user("root", "root", 0, 0, "/root", "/bin/sh");
+    // Seed default users. SUB/SUB is the primary superuser account -- the way
+    // Kali ships with kali/kali -- so the username and password both default to
+    // "SUB". It is seeded first, so uid 0 resolves to it as the logged-in user.
+    auth_add_user("SUB", "SUB", 0, 0, "/root", "/bin/sh");
+    auth_add_user("root", "root", 0, 0, "/root", "/bin/sh"); // kept for compatibility
     auth_add_user("admin", "admin123", 1000, 1000, "/home/admin", "/bin/sh");
     auth_add_user("guest", "guest", 1001, 1001, "/home/guest", "/bin/sh");
 
+    // Log in as SUB by default.
+    auth_set_current_user("SUB");
+
     printk(KERN_INFO "AUTH: Pluggable Authentication & SHA-256 Shadow Password engine active\n");
 }
 

userland/lazybox/lazybox.c

@@ -709,6 +709,8 @@ static int applet_free(int argc, char** argv) {
            total_kb, used_kb, free_kb, free_kb);
     printk("Heap:       %8llu    %8llu    %8llu\n",
            kmalloc_get_total() / 1024, kmalloc_get_used() / 1024, kmalloc_get_free() / 1024);
+    printk("            (dynamic kernel heap, grown on demand %llu time(s))\n",
+           (unsigned long long)heap_get_grow_count());
     return 0;
 }
 
@@ -1137,7 +1139,7 @@ static int applet_aead(int argc, char** argv) {
 static int applet_whoami(int argc, char** argv) {
     (void)argc; (void)argv;
     const user_account_t* u = auth_get_current_user();
-    printk("%s\n", u ? u->username : "root");
+    printk("%s\n", u ? u->username : "SUB");
     return 0;
 }
 
@@ -1652,7 +1654,7 @@ static int applet_ssh(int argc, char** argv) {
         return 1;
     }
 
-    char username[32] = "root";
+    char username[32] = "SUB";
     char host[64] = "localhost";
     uint16_t port = 22;
 
@@ -1774,7 +1776,7 @@ static int applet_logread(int argc, char** argv) {
 }
 
 static int applet_su(int argc, char** argv) {
-    const char* target = (argc >= 2) ? argv[1] : "root";
+    const char* target = (argc >= 2) ? argv[1] : "SUB";
     if (auth_set_current_user(target) == 0) {
         printk(KERN_INFO "Switched to user '%s'\n", target);
         return 0;
@@ -1784,7 +1786,7 @@ static int applet_su(int argc, char** argv) {
 }
 
 static int applet_passwd(int argc, char** argv) {
-    const char* user = (argc >= 2) ? argv[1] : "root";
+    const char* user = (argc >= 2) ? argv[1] : "SUB";
     const char* new_pass = (argc >= 3) ? argv[2] : "password";
     if (auth_change_password(user, new_pass) == 0) {
         printk(KERN_INFO "passwd: password updated successfully for '%s'\n", user);