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feat: use PIC code model for shared libraries, fix shared library bugs

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This commit is contained in:
Daniel Hammer
2026-04-08 17:07:55 +02:00
parent d87c14da25
commit 28d0614511
10 changed files with 85 additions and 25 deletions
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kernel/src/Hal/IDT.cpp
+13 -5
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@@ -71,6 +71,13 @@ namespace Hal {
return frame->CS;
}
static System::PanicFrame* GetExceptionRegs(uint8_t vector, System::PanicFrame* frame) {
if (ExceptionHasErrorCode(vector)) {
return (System::PanicFrame*)((uint8_t*)frame + sizeof(uint64_t));
}
return frame;
}
template<size_t i>
__attribute__((interrupt)) void ExceptionHandler(System::PanicFrame* frame)
{
@@ -85,6 +92,7 @@ namespace Hal {
// instead of panicking the entire system.
if (fromUser && Sched::GetCurrentPid() >= 0) {
auto* proc = Sched::GetCurrentProcessPtr();
auto* regs = GetExceptionRegs(i, frame);
Kt::KernelLogStream(Kt::ERROR, "Exception")
<< ExceptionStrings[i] << " in process \""
<< proc->name << "\" (pid " << proc->pid
@@ -99,11 +107,11 @@ namespace Hal {
rep.exceptionVector = i;
for (int j = 0; j < 32 && ExceptionStrings[i][j]; j++) rep.exceptionName[j] = ExceptionStrings[i][j];
rep.exceptionName[31] = '\0';
rep.instructionPointer = frame->IP;
rep.codeSegment = frame->CS;
rep.flags = frame->Flags;
rep.stackPointer = frame->SP;
rep.stackSegment = frame->SS;
rep.instructionPointer = regs->IP;
rep.codeSegment = regs->CS;
rep.flags = regs->Flags;
rep.stackPointer = regs->SP;
rep.stackSegment = regs->SS;
if (i == 0x0E) {
// Page fault: read CR2 for faulting address
kernel/src/Sched/ElfLoader.cpp
+4 -3
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@@ -268,10 +268,11 @@ namespace Sched {
uint64_t copyEnd = (pageEnd < targetSegFileEnd) ? pageEnd : targetSegFileEnd;
if (copyStart < copyEnd) {
// Source: file data at (copyStart - targetSegStart) offset from p_offset
// Source stays segment-relative, but the destination must be page-relative.
// Using a segment-relative destination offset leaves page 2+ zero-filled and
// writes past the newly allocated page in the kernel mapping.
uint64_t srcOffset = phdr->p_offset + (copyStart - targetSegStart);
// Dest: page at (copyStart - targetSegStart) offset, then adjusted for this page
uint64_t pageDataOffset = copyStart - targetSegStart;
uint64_t pageDataOffset = copyStart - pageStart;
uint64_t copySize = copyEnd - copyStart;
uint8_t* dst = (uint8_t*)Memory::HHDM(physAddr) + pageDataOffset;
programs/GNUmakefile
+2 -2
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@@ -281,8 +281,8 @@ dialogs: bearssl libc tls
crashpad: libc
$(MAKE) -C src/crashpad
# Build test_dl (dynamic loading test app, depends on libloader).
test_dl: libloader libs
# Build test_dl (dynamic loading test app, depends on libloader and shared libs).
test_dl: libloader libs libhello
$(MAKE) -C src/test_dl
# Install app bundles (manifests, icons, data files) into bin/apps/<name>/.
programs/libs/libhello/Makefile
+3 -1
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@@ -11,6 +11,8 @@ NM := $(TOOLCHAIN_PREFIX)nm
STRIP := $(TOOLCHAIN_PREFIX)strip
# Compiler flags: freestanding, no stdlib
# Build as PIE so library-internal data references remain valid after the
# kernel maps the image into a per-process library slot.
override CXXFLAGS := \
-std=gnu++20 \
-g -O2 -pipe \
@@ -20,7 +22,7 @@ override CXXFLAGS := \
-ffreestanding \
-fno-stack-protector \
-fno-stack-check \
-fno-PIC \
-fPIE \
-fno-rtti \
-fno-exceptions \
-ffunction-sections \
programs/libs/libhello/src/libhello.cpp
+38 -10
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@@ -8,18 +8,47 @@
#include <montauk/syscall.h>
#include <gui/truetype.hpp>
// Exported demo function - creates a window and renders until closed
// Heap allocation test - allocates, writes, reads, frees
// Returns 0 on success, -1 on failure
extern "C" int hello_malloc_test() {
// Test 1: Allocate 256 bytes
void* buf = montauk::malloc(256);
if (!buf) {
montauk::print(" [libhello] malloc(256) failed\n");
return -1;
}
// Test 2: Write a pattern and verify it
uint8_t* bytes = (uint8_t*)buf;
for (int i = 0; i < 256; i++) {
bytes[i] = (uint8_t)(i & 0xFF);
}
for (int i = 0; i < 256; i++) {
if (bytes[i] != (uint8_t)(i & 0xFF)) {
montauk::print(" [libhello] read verification failed\n");
montauk::mfree(buf);
return -1;
}
}
montauk::mfree(buf);
return 0;
}
extern "C" int hello_run() {
// Create window
static constexpr int kInitialWidth = 320;
static constexpr int kInitialHeight = 200;
static constexpr uint32_t kBackgroundColor = 0xFFFFFFFF;
Montauk::WinCreateResult wres;
if (montauk::win_create("libhello Demo", 320, 200, &wres) < 0 || wres.id < 0) {
if (montauk::win_create("libhello Demo", kInitialWidth, kInitialHeight, &wres) < 0 || wres.id < 0) {
return -1;
}
int winId = wres.id;
uint32_t* pixels = (uint32_t*)(uintptr_t)wres.pixelVa;
int width = 200;
int height = 320;
int width = kInitialWidth;
int height = kInitialHeight;
gui::TrueTypeFont* font = (gui::TrueTypeFont*)montauk::malloc(sizeof(gui::TrueTypeFont));
if (!font) {
@@ -36,16 +65,15 @@ extern "C" int hello_run() {
// Simple render - fill with a color pattern
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
// Dark blue background
pixels[y * width + x] = 0xFF1a1a2e;
pixels[y * width + x] = kBackgroundColor;
}
}
// Render text using TrueType
gui::Color text_color;
text_color.r = 0xF5;
text_color.g = 0xF5;
text_color.b = 0xF5;
text_color.r = 0x11;
text_color.g = 0x11;
text_color.b = 0x11;
text_color.a = 255;
font->draw_to_buffer(pixels, width, height, 20, 20, "Hello from libhello!", text_color, 16);
@@ -76,7 +104,7 @@ extern "C" int hello_run() {
// Re-render on resize
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
pixels[y * width + x] = 0xFF1a1a2e;
pixels[y * width + x] = kBackgroundColor;
}
}
font->draw_to_buffer(pixels, width, height, 20, 20, "Hello from libhello!", text_color, 16);
programs/libs/libhello/src/libhello.o
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programs/libs/libhello/src/stb_truetype_impl.o
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programs/libs/libmath/Makefile
+4 -2
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@@ -11,6 +11,8 @@ NM := $(TOOLCHAIN_PREFIX)nm
STRIP := $(TOOLCHAIN_PREFIX)strip
# Compiler flags: freestanding, no stdlib
# Build as PIE so library code remains valid when loaded into a slot-specific
# base address by the kernel loader.
override CXXFLAGS := \
-std=gnu++20 \
-g -O2 -pipe \
@@ -20,7 +22,7 @@ override CXXFLAGS := \
-ffreestanding \
-fno-stack-protector \
-fno-stack-check \
-fno-PIC \
-fPIE \
-fno-rtti \
-fno-exceptions \
-ffunction-sections \
@@ -55,7 +57,7 @@ LIBSRC := src/libmath.cpp
all: $(OUTDIR)/$(LIBNAME).lib $(OUTDIR)/$(LIBNAME).lib.sym
$(OUTDIR)/$(LIBNAME).lib: $(LIBSRC)
$(OUTDIR)/$(LIBNAME).lib: $(LIBSRC) Makefile
@mkdir -p $(OUTDIR)
$(CXX) $(CXXFLAGS) -c $(LIBSRC) -o src/libmath.o
$(CXX) $(CXXFLAGS) $(LDFLAGS) src/libmath.o -o $@
programs/libs/libmath/src/libmath.o
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programs/src/test_dl/main.cpp
+20 -1
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@@ -100,7 +100,26 @@ extern "C" void _start() {
// Debug: print hello_run address
montauk::print(" DEBUG: hello_run @ ");
print_hex((uint64_t)hello_run);
montauk::print("\n");
montauk::print("\n\n");
// Test heap allocations in the shared library
montauk::print("Testing heap allocations in libhello...\n");
typedef int (*malloc_test_t)(void);
malloc_test_t malloc_test = (malloc_test_t)libloader::dlsym(hellolib, "hello_malloc_test");
if (!malloc_test) {
montauk::print("ERROR: Failed to resolve hello_malloc_test\n");
libloader::dlclose(hellolib);
montauk::exit(1);
}
montauk::print(" hello_malloc_test: OK\n");
int malloc_result = malloc_test();
if (malloc_result != 0) {
montauk::print("ERROR: heap allocation test in libhello failed\n");
libloader::dlclose(hellolib);
montauk::exit(1);
}
montauk::print(" heap allocation test: PASSED\n\n");
// Run the GUI demo (this creates a window and event loop)
montauk::print("Running GUI demo...\n");