Disallow syscalls before libc is initialised, remove all existing early boot syscalls

api/kernel/memmap.hpp

@@ -324,7 +324,7 @@ class Fixed_memory_range {
 class Memory_map {
 public:
   using Key = uintptr_t;
-  using Map = std::map<Key, Fixed_memory_range>;
+  using Map = std::pmr::map<Key, Fixed_memory_range>;
 
   /**
    * Assign a fixed range of memory to a named purpose

chainloader.nix

@@ -43,8 +43,4 @@ stdenv.mkDerivation rec {
     pkgs.buildPackages.cmake
     pkgs.buildPackages.nasm
   ];
-
-  buildInputs = [
-    pkgs.microsoft_gsl
-  ];
 }

cmake/includeos.cmake

@@ -72,7 +72,7 @@ if (NOT ${PLATFORM} STREQUAL "userspace")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${CAPABS} ${WARNS}  -nostdlib -fno-omit-frame-pointer -c")
   else()
     # these kinda work with llvm
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CAPABS} ${WARNS} -nostdlib -nostdlibinc -fno-omit-frame-pointer -c")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CAPABS} ${WARNS} -nostdlib -nostdlibinc -fno-omit-frame-pointer -c -fno-threadsafe-statics")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${CAPABS} ${WARNS} -nostdlib  -nostdlibinc -fno-omit-frame-pointer -c")
   endif()
 endif()

cmake/library.cmake

@@ -57,11 +57,11 @@ if (debug)
 endif()
 
 if (CMAKE_COMPILER_IS_GNUCC)
-  set(CMAKE_CXX_FLAGS "-m32 -MMD ${CAPABS} ${WARNS} -nostdlib -fno-omit-frame-pointer -c -std=c++14 -D_LIBCPP_HAS_NO_THREADS=1")
+  set(CMAKE_CXX_FLAGS "-m32 -MMD ${CAPABS} ${WARNS} -nostdlib -fno-omit-frame-pointer -c -std=c++20 -D_LIBCPP_HAS_NO_THREADS=1")
   set(CMAKE_C_FLAGS "-m32 -MMD ${CAPABS} ${WARNS} -nostdlib -fno-omit-frame-pointer -c")
 else()
   # these kinda work with llvm
-  set(CMAKE_CXX_FLAGS "-MMD ${CAPABS} ${OPTIMIZE} ${WARNS} -nostdlib -nostdlibinc -fno-omit-frame-pointer -c -std=c++14 -D_LIBCPP_HAS_NO_THREADS=1")
+  set(CMAKE_CXX_FLAGS "-MMD ${CAPABS} ${OPTIMIZE} ${WARNS} -nostdlib -nostdlibinc -fno-omit-frame-pointer -c -std=c++20 -fno-threadsafe-statics -D_LIBCPP_HAS_NO_THREADS=1")
   set(CMAKE_C_FLAGS "-MMD ${CAPABS} ${OPTIMIZE} ${WARNS} -nostdlib -nostdlibinc -fno-omit-frame-pointer -c")
 endif()
 

src/arch/x86_64/ist.cpp

@@ -70,7 +70,7 @@ static stack create_stack_virt(size_t size, const char* name)
 }
 static stack create_stack_simple(size_t size, const char* /*name*/)
 {
-  auto* phys = (char*)memalign(4096, size);
+  auto* phys = (char*)kalloc_aligned(4096, size);
   uintptr_t sp = (uintptr_t) phys + size - 8;
   sp &= ~uintptr_t(0xf);
   return {(void*) sp, phys};

src/crt/CMakeLists.txt

@@ -1,8 +1,7 @@
-SET(SRCS
+SET(SRCS
     c_abi.c
     ctype_b_loc.c
     ctype_tolower_loc.c
-    string.c
     quick_exit.cpp
     cxx_abi.cpp
     )

src/include/kernel.hpp

@@ -30,7 +30,8 @@ namespace kernel {
   struct State {
     bool running               = true;
     bool boot_sequence_passed  = false;
-    bool libc_initialized      = false;
+    bool libc_initialized      = false; // Set when __libc_main returns
+    bool allow_syscalls        = false; // Set before calling into libc
     bool block_drivers_ready   = false;
     bool timestamps            = false;
     bool timestamps_ready      = false;
@@ -62,6 +63,10 @@ namespace kernel {
     return state().libc_initialized;
   }
 
+  inline bool allow_syscalls() noexcept {
+    return state().allow_syscalls;
+  }
+
   inline bool block_drivers_ready() noexcept {
     return state().block_drivers_ready;
   }

src/kernel/heap.cpp

@@ -70,5 +70,10 @@ void kernel::init_heap(uintptr_t free_mem_begin, uintptr_t memory_end) noexcept
   auto brk_end  = __init_brk(kernel::heap_begin(), __brk_max);
   Expects(brk_end <= memory_end);
   __init_mmap(brk_end, memory_end);
+
+  // Also set the PMR default allocator to use the same allocator as mmap
+  auto& alloc = os::mem::raw_allocator();
+  std::pmr::set_default_resource(&alloc);
+
   __heap_ready = true;
 }

src/kernel/multiboot.cpp

@@ -141,7 +141,7 @@ void kernel::multiboot(uint32_t boot_addr)
   if (info->flags & MULTIBOOT_INFO_CMDLINE) {
     const auto* cmdline = (const char*) (uintptr_t) info->cmdline;
     INFO2("* Booted with parameters @ %p: %s", cmdline, cmdline);
-    kernel::state().cmdline = strdup(cmdline);
+    kernel::state().cmdline = std::pmr::string(cmdline).data();
   }
 
   if (info->flags & MULTIBOOT_INFO_MEM_MAP) {
@@ -178,7 +178,7 @@ void kernel::multiboot(uint32_t boot_addr)
         //os::mem::map_avail({map.addr, map.addr, {os::mem::Access::read | os::mem::Access::write}, map.len}, "Reserved (Multiboot)");
       }
     }
-    printf("\n");
+    INFO2("");
   }
 
   auto mods = os::modules();

src/musl/common.hpp

@@ -51,8 +51,6 @@ inline constexpr auto& pr_param(std::ostream& out,  L lhs, Args&&... rest){
 
 template <typename Ret, typename ...Args>
 inline void strace_print(const char* name, Ret ret, Args&&... args){
-  if (not kernel::state().libc_initialized)
-    return;
 
   std::stringstream out;
   out << name << "(";
@@ -74,6 +72,11 @@ inline void strace_print(const char* name, Ret ret, Args&&... args){
 // strace, calling the syscall, recording return value and printing if enabled
 template<typename Fn, typename ...Args>
 inline auto strace(Fn func, [[maybe_unused]]const char* name, Args&&... args) {
+  if (!kernel::state().allow_syscalls) {
+    fprintf(stderr, "Syscalls not allowed here. Unexpected call to %s - terminating\n", name);
+    Expects(kernel::state().allow_syscalls);
+  }
+
   auto ret = func(args...);
 
   if constexpr (__strace)

src/musl/stub.hpp

@@ -13,6 +13,11 @@ inline void stubtrace_print(const char* name, R ret, Args&&... args) {
 // calling the syscall, recording return value and only printing when strace is on
 template<typename Fn, typename ...Args>
 inline auto stubtrace(Fn func, const char* name[[maybe_unused]], Args&&... args) {
+  if (!kernel::state().allow_syscalls) {
+    fprintf(stderr, "Syscalls not allowed here. Unexpected call to %s (stub) - terminating\n", name);
+    Expects(kernel::state().allow_syscalls);
+  }
+
   auto ret = func(args...);
 
   if constexpr (__strace)

src/platform/x86_nano/kernel_start.cpp

@@ -25,8 +25,8 @@
 extern "C" {
   void __init_sanity_checks();
   uintptr_t _move_symbols(uintptr_t loc);
-  void _init_bss();
   void _init_heap(uintptr_t);
+  void _init_elf_parser();
   void _init_syscalls();
 }
 
@@ -57,6 +57,9 @@ void kernel_start(uintptr_t magic, uintptr_t addr)
   // Initialize heap
   kernel::init_heap(free_mem_begin, mem_end);
 
+  // Get backtrace on nano too
+  _init_elf_parser();
+
   // Initialize system calls
   _init_syscalls();
 

src/platform/x86_pc/init_libc.cpp

@@ -103,9 +103,9 @@ namespace x86
     int argc = 1;
 
     // Env vars
-    argv[2] = strdup("LC_CTYPE=C");
-    argv[3] = strdup("LC_ALL=C");
-    argv[4] = strdup("USER=root");
+    argv[2] = std::pmr::string("LC_CTYPE=C").data();
+    argv[3] = std::pmr::string("LC_ALL=C").data();
+    argv[4] = std::pmr::string("USER=root").data();
     argv[5] = 0x0;
 
     // auxiliary vector
@@ -161,6 +161,7 @@ namespace x86
 
     // GDB_ENTRY;
     PRATTLE("* Starting libc initialization\n");
+    kernel::state().allow_syscalls = true;
     __libc_start_main(kernel_main, argc, argv.data());
   }
 }

test/kernel/integration/grub/test.py

@@ -14,4 +14,4 @@
 
 # Create the GRUB image
 subprocess.check_call(["bash",grubify,"kernel_grub.elf.bin"])
-vm.boot(multiboot = False)
+vm.boot(20, multiboot = False)