/* Init TLS for the initial thread. Called by the linker _before_ libc is mapped
 * in memory. Beware: all writes to libc globals from this function will
 * apply to linker-private copies and will not be visible from libc later on.
 *
 * Note: this function creates a pthread_internal_t for the initial thread and
 * stores the pointer in TLS, but does not add it to pthread's thread list. This
 * has to be done later from libc itself (see __libc_init_common).
 *
 * This function also stores a pointer to the kernel argument block in a TLS slot to be
 * picked up by the libc constructor.
 */
void __libc_init_tls(KernelArgumentBlock& args) {
  __libc_auxv = args.auxv;

  static void* tls[BIONIC_TLS_SLOTS];
  static pthread_internal_t main_thread;
  main_thread.tls = tls;

  // Tell the kernel to clear our tid field when we exit, so we're like any other pthread.
  // As a side-effect, this tells us our pid (which is the same as the main thread's tid).
  main_thread.tid = __set_tid_address(&main_thread.tid);
  main_thread.set_cached_pid(main_thread.tid);

  // Work out the extent of the main thread's stack.
  uintptr_t stack_top = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
  size_t stack_size = get_main_thread_stack_size();
  void* stack_bottom = reinterpret_cast<void*>(stack_top - stack_size);

  // We don't want to free the main thread's stack even when the main thread exits
  // because things like environment variables with global scope live on it.
  pthread_attr_init(&main_thread.attr);
  pthread_attr_setstack(&main_thread.attr, stack_bottom, stack_size);
  main_thread.attr.flags = PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK | PTHREAD_ATTR_FLAG_MAIN_THREAD;

  __init_thread(&main_thread, false);
  __init_tls(&main_thread);
  __set_tls(main_thread.tls);
  tls[TLS_SLOT_BIONIC_PREINIT] = &args;

  __init_alternate_signal_stack(&main_thread);
}
void __libc_init_main_thread(KernelArgumentBlock& args) {
  __libc_auxv = args.auxv;
#if defined(__i386__)
  __libc_init_sysinfo(args);
#endif

  static pthread_internal_t main_thread;

  // The -fstack-protector implementation uses TLS, so make sure that's
  // set up before we call any function that might get a stack check inserted.
  // TLS also needs to be set up before errno (and therefore syscalls) can be used.
  __set_tls(main_thread.tls);
  __init_tls(&main_thread);

  // Tell the kernel to clear our tid field when we exit, so we're like any other pthread.
  // As a side-effect, this tells us our pid (which is the same as the main thread's tid).
  main_thread.tid = __set_tid_address(&main_thread.tid);
  main_thread.set_cached_pid(main_thread.tid);

  // We don't want to free the main thread's stack even when the main thread exits
  // because things like environment variables with global scope live on it.
  // We also can't free the pthread_internal_t itself, since that lives on the main
  // thread's stack rather than on the heap.
  // The main thread has no mmap allocated space for stack or pthread_internal_t.
  main_thread.mmap_size = 0;
  pthread_attr_init(&main_thread.attr);
  main_thread.attr.guard_size = 0; // The main thread has no guard page.
  main_thread.attr.stack_size = 0; // User code should never see this; we'll compute it when asked.
  // TODO: the main thread's sched_policy and sched_priority need to be queried.

  // The TLS stack guard is set from the global, so ensure that we've initialized the global
  // before we initialize the TLS. Dynamic executables will initialize their copy of the global
  // stack protector from the one in the main thread's TLS.
  __libc_init_global_stack_chk_guard(args);
  __init_thread_stack_guard(&main_thread);

  __init_thread(&main_thread);

  // Store a pointer to the kernel argument block in a TLS slot to be
  // picked up by the libc constructor.
  main_thread.tls[TLS_SLOT_BIONIC_PREINIT] = &args;

  __init_alternate_signal_stack(&main_thread);
}
extern "C" void __libc_init_main_thread_early(const KernelArgumentBlock& args,
                                              bionic_tcb* temp_tcb) {
  __libc_shared_globals()->auxv = args.auxv;
#if defined(__i386__)
  __libc_init_sysinfo(); // uses AT_SYSINFO auxv entry
#endif
  __init_tcb(temp_tcb, &main_thread);
  __init_tcb_dtv(temp_tcb);
  __set_tls(&temp_tcb->tls_slot(0));
  main_thread.tid = __getpid();
  main_thread.set_cached_pid(main_thread.tid);
}