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);
}
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);
}
