fix: guard against uint32 underflow in memset/memcpy and strings unit

When size=0 was passed to memset() or memcpy(), the loop bound
`0 to size-1` underflowed to $FFFFFFFF, iterating ~4 billion times
and causing an immediate page fault.

Added `if size = 0 then exit` guards to both memset() and memcpy()
in util.pas.

Also guarded all `for i:=0 to X-1` loops in strings.pas where X
could be 0 on empty string inputs:
- stringToUpper: wrap loop in `if stringSize > 0`
- stringToLower: wrap loop in `if stringSize > 0`
- stringEquals: early exit when both sizes are 0
- stringToInt: early exit when string is empty

Additionally fixed all previously identified bugs in strings.pas:
- hexStringToInt: guard against empty string underflow
- stringConcat: cache stringSize calls to avoid redundant O(n) scans
- stringTrim: clamp length to source string size
- stringSub: bounds check start/size against source length
- stringReplace: complete rewrite - was using stringEquals() for
  substring matching (only matched at string end), dropped prefix
  chars, had dangling assignment overwriting valid result with
  uninitialized pointer, and had unused variable
- stringIndexOf: rewritten to use new stringMatchAt() helper for
  correct substring matching
- stringContains: simplified to delegate to fixed stringIndexOf(),
  also fixing uint32 underflow when sub was empty
- stringToInt: removed always-true `v >= 0` check on uint32
- intToString: implemented (was a stub returning ' ')
- Added stringMatchAt() helper for prefix comparison
- Added comprehensive UnitTest procedure with 77 assertions
  including adversarial empty/nil/boundary inputs

.gitattributes

@@ -1,8 +1 @@
 * text=auto eol=lf
-lvglh/** linguist-vendored
-lvgl/** linguist-vendored
-.vscode/* linguist-vendored
-lib/* linguist-generated
-release/* linguist-generated
-iso/* linguist-generated
-*.asm linguist-detectable

.gitignore

@@ -11,9 +11,6 @@
 /*.img
 src/include/asuro.pas
 localenv.json
-/lvgl/
-dockerout.txt
 AGENTS.md
-lessons_learnt.md
+build.log
-*.log
+dockerout.txt
-/doc/*.md

Dockerfile

@@ -5,7 +5,7 @@ VOLUME ["/code"]
 ENV DEBIAN_FRONTEND=noninteractive
 RUN dpkg --add-architecture i386
 RUN apt-get update && apt-get install -y \
-	curl dos2unix wget git make nasm binutils xorriso grub-pc-bin gcc gcc-multilib && \
+	curl dos2unix wget git make nasm binutils:i386 xorriso grub-pc-bin && \
 	apt-get clean my room
 
 SHELL ["/bin/bash", "-c"]

compile.sh

@@ -7,7 +7,7 @@ echo "Asuro Compilation"
 echo " "
 
 #Compile Stub.asm
-rm -f lib/*
+rm lib/*
 
 runOrFail() {
 	local binary=$1
@@ -23,7 +23,6 @@ runOrFail() {
 declare -a run_steps=(
 	"compile_stub.sh" "Failed to compile stub!"
 	"compile_vergen.sh" "Versions failed to compile"
-	"compile_lvgl.sh" "Failed to compile LVGL!"
 	"compile_sources.sh" "Failed to compile FPC Sources!"
 	"compile_link.sh" "Failed linking!"
 	"compile_isogen.sh" "Failed to create ISO!"

compile_link.sh

@@ -14,9 +14,4 @@ done;
 objstring=lib/stub.o" "$objstring 
 echo "Object Files: "$objstring
 echo " "
-
+ld -m elf_i386 -s --gc-sections -Tlinker.script -o bin/kernel.bin $objstring
-# Find libgcc for i386 (needed by LVGL compiled with gcc)
-LIBGCC=$(gcc -m32 -print-libgcc-file-name)
-echo "libgcc: ${LIBGCC}"
-
-ld -m elf_i386 -s --gc-sections -Tlinker.script -o bin/kernel.bin $objstring --start-group lib/liblvgl.a ${LIBGCC} --end-group

compile_lvgl.sh

@@ -1,132 +0,0 @@
-#!/usr/bin/env bash
-# compile_lvgl.sh — Download LVGL v9.2 source and compile into lib/liblvgl.a
-# Clone & compile in /tmp (fast container-local fs).
-# Cache liblvgl.a on host mount (/code/lvgl/) to skip rebuild.
-set -e
-
-LVGL_VERSION="v9.2.2"
-LVGL_REPO="https://github.com/lvgl/lvgl.git"
-LVGL_DIR="/tmp/lvgl"
-OBJ_DIR="/tmp/lvgl_obj"
-CONF_DIR="$(pwd)/lvglh"
-OUT_DIR="$(pwd)/lib"
-CACHE_DIR="/code/lvgl"
-
-CC="gcc"
-CFLAGS="-m32 -march=i686 -ffreestanding \
-    -fno-builtin -fno-stack-protector -fno-pic -fno-pie \
-    -O2 -Wall -Wno-unused-function -Wno-unused-variable \
-    -I${CONF_DIR} \
-    -I${LVGL_DIR} \
-    -I${LVGL_DIR}/.. \
-    -DLV_CONF_INCLUDE_SIMPLE"
-
-echo " "
-echo "======================="
-echo " "
-echo "Compiling LVGL..."
-echo " "
-
-# If cached liblvgl.a exists on host mount, just copy it and skip everything
-if [ -f "${CACHE_DIR}/liblvgl.a" ]; then
-    echo "Found cached liblvgl.a in ${CACHE_DIR}, copying to ${OUT_DIR}..."
-    cp "${CACHE_DIR}/liblvgl.a" "${OUT_DIR}/liblvgl.a"
-    echo "(Delete lvgl/liblvgl.a to force a full rebuild.)"
-    echo " "
-    echo "LVGL compilation complete (cached)."
-    echo " "
-    exit 0
-fi
-
-# Clone LVGL into /tmp (container-local)
-rm -rf "$LVGL_DIR"
-echo "Downloading LVGL ${LVGL_VERSION}..."
-git clone --depth 1 --branch "${LVGL_VERSION}" "${LVGL_REPO}" "${LVGL_DIR}" 2>&1
-echo "Download complete."
-
-# Gather all LVGL .c source files (core library only, no demos/examples)
-SOURCES=$(find "${LVGL_DIR}/src" -name '*.c' -not -path '*/test/*')
-TOTAL=$(echo "$SOURCES" | wc -l)
-echo "Found ${TOTAL} LVGL source files."
-
-# Compile each .c file to .o (container-local)
-rm -rf "$OBJ_DIR"
-mkdir -p "$OBJ_DIR"
-
-COUNT=0
-ERRORS=0
-for src in $SOURCES; do
-    COUNT=$((COUNT + 1))
-    rel="${src#${LVGL_DIR}/src/}"
-    obj_path="${OBJ_DIR}/${rel%.c}.o"
-    mkdir -p "$(dirname "$obj_path")"
-
-    if ! $CC $CFLAGS -c "$src" -o "$obj_path" 2>&1; then
-        echo "FAILED: $rel"
-        ERRORS=$((ERRORS + 1))
-    fi
-
-    if [ $((COUNT % 50)) -eq 0 ]; then
-        echo "  Compiled ${COUNT}/${TOTAL}..."
-    fi
-done
-
-echo "Compiled ${COUNT} files (${ERRORS} errors)."
-
-if [ "$ERRORS" -ne 0 ]; then
-    echo "LVGL compilation FAILED with ${ERRORS} errors."
-    exit 1
-fi
-
-# Archive into static library
-OBJECTS=$(find "$OBJ_DIR" -name '*.o')
-ar rcs "${OUT_DIR}/liblvgl.a" $OBJECTS
-echo "Created ${OUT_DIR}/liblvgl.a"
-
-# Compile custom LVGL extension files from lvglh/
-LVGLH_SOURCES=$(find "${CONF_DIR}" -name '*.c' 2>/dev/null || true)
-if [ -n "$LVGLH_SOURCES" ]; then
-    echo " "
-    echo "Compiling custom LVGL files from lvglh/..."
-    LVGLH_OBJ_DIR="/tmp/lvglh_obj"
-    rm -rf "$LVGLH_OBJ_DIR"
-    mkdir -p "$LVGLH_OBJ_DIR"
-    HCOUNT=0
-    HERRORS=0
-    for src in $LVGLH_SOURCES; do
-        HCOUNT=$((HCOUNT + 1))
-        rel="${src#${CONF_DIR}/}"
-        obj_path="${LVGLH_OBJ_DIR}/${rel%.c}.o"
-        mkdir -p "$(dirname "$obj_path")"
-        echo "  [lvglh] $rel"
-        if ! $CC $CFLAGS -c "$src" -o "$obj_path" 2>&1; then
-            echo "  FAILED: $rel"
-            HERRORS=$((HERRORS + 1))
-        fi
-    done
-    echo "Compiled ${HCOUNT} custom files (${HERRORS} errors)."
-    if [ "$HERRORS" -ne 0 ]; then
-        echo "Custom LVGL compilation FAILED."
-        exit 1
-    fi
-    # Append custom objects into the existing archive
-    HOBJECTS=$(find "$LVGLH_OBJ_DIR" -name '*.o')
-    ar rcs "${OUT_DIR}/liblvgl.a" $HOBJECTS
-    echo "Updated ${OUT_DIR}/liblvgl.a with custom objects."
-else
-    echo "No custom LVGL files in lvglh/."
-fi
-
-# Cache liblvgl.a and source to host mount for next build
-echo "Caching LVGL to host mount..."
-mkdir -p "$CACHE_DIR"
-rm -rf ${CACHE_DIR}/* ${CACHE_DIR}/.[!.]* ${CACHE_DIR}/..?* 2>/dev/null || true
-cp "${OUT_DIR}/liblvgl.a" "${CACHE_DIR}/liblvgl.a"
-cp -a "$LVGL_DIR/src" "${CACHE_DIR}/src"
-cp -a "$LVGL_DIR"/*.h "${CACHE_DIR}/" 2>/dev/null || true
-cp -a "$OBJ_DIR" "${CACHE_DIR}/obj"
-echo "Done."
-
-echo " "
-echo "LVGL compilation complete."
-echo " "

compile_sources.sh

@@ -4,10 +4,4 @@ echo "======================="
 echo " "
 echo "Compiling FPC Sources..."
 echo " "
-# Build -Fu flags for all directories under src/ and wasuro/
+fpc -Aelf -gw -g -gl -n -vlewn -O3 -OpPENTIUM3 -Si -Sc -Sg -Xd -CX -XXs -CfSSE -CfSSE2 -Rintel -Pi386 -Tlinux -FElib/ -Fusrc/* -Fusrc/driver/* -Fusrc/driver/net/* src/kernel.pas
-FU_PATHS="-Fusrc -Fuwasuro"
-for dir in $(find src wasuro -type d 2>/dev/null); do
-    FU_PATHS="$FU_PATHS -Fu$dir"
-done
-
-fpc -Aelf -gw -g -gl -n -v0e -O3 -OpPENTIUM3 -Si -Sc -Sg -Xd -CX -XXs -CfSSE -CfSSE2 -Rintel -Pi386 -Tlinux -FElib/ $FU_PATHS src/kernel.pas

compile_stub.sh

@@ -5,4 +5,3 @@ echo " "
 echo "Compiling Stub..."
 echo " "
 nasm -f elf src/stub/stub.asm -o lib/stub.o
-nasm -f elf src/stub/splash_tga.asm -o lib/splash_tga.o

doc/flatfs.md

@@ -1,32 +0,0 @@
-#Flat filesystem
-
-A super simple filesystem for asuro. Folders are emulated in filenames.
-
-Starts with disk info sector, sector 0 of volume
-
----
-#### disk info
-
-jmp2boot        : ubit24;
-OEMName         : array[0..7] of char;
-version         : uint16 // numerical version of filesystem
-sectorCount      : uint16;
-fileCount       : uint16
-signature       : uint32 = 0x0B00B1E5
-
-
-the Rest of the sector is reserved
-
----
-
-Starting from sector 1 is the file table. Table size is determined by entry size (64) * fileCount
-
----
-####File entry
-
-name : array[0..59] of char //file name max 60 chars
-fileStart : 16bit // start sector of data
-fileSize : 16bit // data size in sectors
-
----
-

iso/hello.txt

@@ -1 +0,0 @@
-Hello from the Asuro ISO!

src/contextswitcher.pas

@@ -13,117 +13,14 @@
 //  limitations under the License.
 
 { 
-    ContextSwitcher - Custom IRQ0 handler for preemptive context switching.
+	ContextSwitcher - Switch Process Contexts when preempted.
 	
-    Replaces the default ISR_32 with a naked assembly stub that saves the
+	@author(Kieron Morris <[email protected]>)
-    interrupted context (PUSHAD + segment regs), calls a Pascal helper to
-    dispatch timer hooks, send EOI, and run the scheduler, then restores
-    the next process context (or idles) via the returned ESP.
-
-    @author(Kieron Morris <[email protected]>)
 }
 unit contextswitcher;
 
-{$ASMMODE intel}
-
 interface
 
-uses
+implementation;
-    idt, isrmanager, processmanager, proctypes, util, tracer;
-
-{ Initialise: overwrite IDT gate 32 with our custom ISR. }
-procedure init;
-
-implementation
-
-{ -----------------------------------------------------------------------
-  do_context_switch_work
-  Pascal helper called from the assembly ISR.  Receives the current ESP
-  (pointing to the GS..EFLAGS save area), dispatches timer hooks, sends
-  EOI, runs the scheduler and returns the ESP for the next context.
-  Uses register calling convention: saved_esp in EAX, result in EAX.
-  ----------------------------------------------------------------------- }
-function do_context_switch_work(saved_esp : uint32) : uint32;
-var
-    next : PProcessContext;
-begin
-    { 1. Save ESP into the current process }
-    processmanager.CurrentProcess^.SavedESP := saved_esp;
-
-    { 2. Dispatch all hooks registered on interrupt 32 (timer hooks).
-         This fires TMR_0_ISR.Main which in turn fires BDA tick,
-         graphics refresh, USB hotplug, etc. }
-    isrmanager.dispatchHooks(32);
-
-    { 3. Send End-Of-Interrupt to the master PIC }
-    outb($20, $20);
-
-    { 4. Pick the next process to run (always returns non-nil; idle as fallback) }
-    next := processmanager.scheduler_pick_next;
-    processmanager.CurrentProcess := next;
-
-    { 5. Return the selected process ESP }
-    do_context_switch_work := next^.SavedESP;
-end;
-
-{ -----------------------------------------------------------------------
-  context_switch_isr
-  Naked assembly ISR that replaces ISR_32 (IRQ0 / PIT timer).
-
-  Stack on entry (pushed by CPU):
-      [ESP+8] EFLAGS
-      [ESP+4] CS
-      [ESP+0] EIP
-
-  We push general-purpose and segment registers, call the Pascal helper,
-  switch ESP to the returned value, pop registers and IRETD.
-  ----------------------------------------------------------------------- }
-procedure context_switch_isr; assembler; nostackframe;
-asm
-    { Save all general-purpose registers (EAX,ECX,EDX,EBX,ESP,EBP,ESI,EDI) }
-    pushad
-
-    { Save segment registers }
-    push ds
-    push es
-    push fs
-    push gs
-
-    { Load kernel data segments }
-    mov ax, $10
-    mov ds, ax
-    mov es, ax
-    mov fs, ax
-    mov gs, ax
-
-    { Call Pascal helper: EAX = current ESP (register calling convention).
-      Returns new ESP in EAX. }
-    mov eax, esp
-    call do_context_switch_work
-    mov esp, eax
-
-    { Restore segment registers }
-    pop gs
-    pop fs
-    pop es
-    pop ds
-
-    { Restore general-purpose registers }
-    popad
-
-    { Return from interrupt }
-    iretd
-end;
-
-{ -----------------------------------------------------------------------
-  init
-  Override IDT gate 32 with our custom ISR.  Must be called AFTER
-  isrmanager.init so that the default gate has been set up first.
-  ----------------------------------------------------------------------- }
-procedure init;
-begin
-    idt.set_gate(32, uint32(@context_switch_isr), $08, ISR_RING_0);
-    tracer.push_trace('contextswitcher.init');
-end;
 
 end.

src/driver/bus/EHCI.pas

@@ -0,0 +1,65 @@
+//  Copyright 2021 Kieron Morris
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ 
+	Driver->Bus->EHCI - Enhanced Host Controller Interface Driver.
+	
+	@author(Kieron Morris <[email protected]>)
+}
+unit EHCI;
+
+interface
+
+uses
+    tracer,
+    Console,
+    PCI,
+    drivertypes,
+    pmemorymanager,
+    vmemorymanager,
+    util,
+    drivermanagement;
+
+function load : boolean;
+
+implementation
+
+function load : boolean;
+var
+    devices : TDeviceArray;
+    count   : uint32;
+    i       : uint32;
+
+begin
+    tracer.push_trace('EHCI.load');
+    devices:= PCI.getDeviceInfo($0C, $03, $20, count);
+    console.output('USB-EHCI Driver', 'Found ');
+    console.writeint(count);
+    console.writestringln(' USB Controller(s).');
+    if count > 0 then begin
+        for i:=0 to count-1 do begin
+            console.output('USB-EHCI Driver', 'Controller[');
+            console.writeint(i);
+            console.writestring(']: ');
+            console.writehex(devices[i].device_id);
+            console.writestring(' ');
+            console.writehex(devices[i].vendor_id);
+            console.writestring(' ');
+            console.writehexln(devices[i].prog_if);
+        end;
+    end;
+    load:= true;
+end;
+
+end.

src/driver/bus/OHCI.pas

@@ -0,0 +1,96 @@
+//  Copyright 2021 Kieron Morris
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ 
+	Driver->Bus->OHCI - Open Host Controller Interface Driver.
+	
+	@author(Kieron Morris <[email protected]>)
+}
+unit OHCI;
+
+interface
+
+uses
+    tracer,
+    Console,
+    PCI,
+    drivertypes,
+    pmemorymanager,
+    vmemorymanager,
+    util,
+    drivermanagement;
+
+type
+    POHCI_MMR = ^TOHCI_MMR;
+    TOHCI_MMR = packed record
+        HcRevision : uint32;
+        HcControl  : uint32;
+        HcCommandStatus : uint32;
+        HcIntStatus  : uint32;
+        HcIntEnable  : uint32;
+        HcIntDisable : uint32;
+        HcHCCA : uint32;
+        HcPeriodCurrentED : uint32;
+        HcControlHeadED : uint32;
+        HcControlCurrentED : uint32;
+        HcBulkHeadED : uint32;
+        HcBulkCurrentED : uint32;
+        HcDoneHead : uint32;
+        HcFmRemaining : uint32;
+        HcFmNumber : uint32;
+        HcPeriodicStart : uint32;
+        HcLSThreshold : uint32;
+        HcRhDescriptorA : uint32;
+        HcRhDescriptorB : uint32;
+        HcRhStatus : uint32;
+    end;
+
+function load : boolean;
+
+implementation
+
+function load : boolean;
+var
+    devices : TDeviceArray;
+    count   : uint32;
+    i       : uint32;
+    block   : uint32;
+    MMR     : POHCI_MMR;
+
+begin
+    tracer.push_trace('OHCI.load');
+    devices:= PCI.getDeviceInfo($0C, $03, $10, count);
+    console.output('USB-OHCI Driver', 'Found ');
+    console.writeint(count);
+    console.writestringln(' USB Controller(s).');
+    if count > 0 then begin
+        for i:=0 to count-1 do begin
+            console.output('USB-OHCI Driver', 'Controller[');
+            console.writeint(i);
+            console.writestring(']: ');
+            console.writehex(devices[i].device_id);
+            console.writestring(' ');
+            console.writehex(devices[i].vendor_id);
+            console.writestring(' ');
+            console.writehexln(devices[i].prog_if);
+            block:= devices[i].address0 SHR 22;
+            force_alloc_block(block, 0);
+            map_page(block, block);
+            MMR:= POHCI_MMR(devices[i].address0);
+        end;
+    end;
+    load:= true;
+end;
+
+end.