pthread.c

Axis 221 camera embedded programing interface

     immediately beyond, and one page to act as a guard page). */

#ifdef __ARCH_HAS_MMU__
  /* We cannot allocate a huge chunk of memory to mmap all thread stacks later
   * on a non-MMU system. Thus, we don't need the rlimit either. -StS */
  getrlimit(RLIMIT_STACK, &limit);
  max_stack = STACK_SIZE - 2 * __getpagesize();
  if (limit.rlim_cur > max_stack) {
    limit.rlim_cur = max_stack;
    setrlimit(RLIMIT_STACK, &limit);
  }
#else
  /* For non-MMU assume __pthread_initial_thread_tos at upper page boundary, and
   * __pthread_initial_thread_bos at address 0. These bounds are refined as we 
   * malloc other stack frames such that they don't overlap. -StS
   */
  __pthread_initial_thread_tos =
    (char *)(((long)CURRENT_STACK_FRAME + __getpagesize()) & ~(__getpagesize() - 1));
  __pthread_initial_thread_bos = (char *) 1; /* set it non-zero so we know we have been here */
  PDEBUG("initial thread stack bounds: bos=%p, tos=%p\n",
	 __pthread_initial_thread_bos, __pthread_initial_thread_tos);
#endif /* __ARCH_HAS_MMU__ */

  /* Setup signal handlers for the initial thread.
     Since signal handlers are shared between threads, these settings
     will be inherited by all other threads. */
  sa.sa_handler = pthread_handle_sigrestart;
  sigemptyset(&sa.sa_mask);
  sa.sa_flags = 0;
  __libc_sigaction(__pthread_sig_restart, &sa, NULL);
  sa.sa_handler = pthread_handle_sigcancel;
  // sa.sa_flags = 0;
  __libc_sigaction(__pthread_sig_cancel, &sa, NULL);
  if (__pthread_sig_debug > 0) {
      sa.sa_handler = pthread_handle_sigdebug;
      sigemptyset(&sa.sa_mask);
      // sa.sa_flags = 0;
      __libc_sigaction(__pthread_sig_debug, &sa, NULL);
  }
  /* Initially, block __pthread_sig_restart. Will be unblocked on demand. */
  sigemptyset(&mask);
  sigaddset(&mask, __pthread_sig_restart);
  sigprocmask(SIG_BLOCK, &mask, NULL);
  /* Register an exit function to kill all other threads. */
  /* Do it early so that user-registered atexit functions are called
     before pthread_onexit_process. */
  on_exit(pthread_onexit_process, NULL);
}

void __pthread_initialize(void)
{
  pthread_initialize();
}

int __pthread_initialize_manager(void)
{
  int manager_pipe[2];
  int pid;
  int report_events;
  struct pthread_request request;

  /* If basic initialization not done yet (e.g. we're called from a
     constructor run before our constructor), do it now */
  if (__pthread_initial_thread_bos == NULL) pthread_initialize();
  /* Setup stack for thread manager */
  __pthread_manager_thread_bos = malloc(THREAD_MANAGER_STACK_SIZE);
  if (__pthread_manager_thread_bos == NULL) return -1;
  __pthread_manager_thread_tos =
    __pthread_manager_thread_bos + THREAD_MANAGER_STACK_SIZE;

  /* On non-MMU systems we make sure that the initial thread bounds don't overlap
   * with the manager stack frame */
  NOMMU_INITIAL_THREAD_BOUNDS(__pthread_manager_thread_tos,__pthread_manager_thread_bos);
  PDEBUG("manager stack: size=%d, bos=%p, tos=%p\n", THREAD_MANAGER_STACK_SIZE,
	 __pthread_manager_thread_bos, __pthread_manager_thread_tos);
#if 0
  PDEBUG("initial stack: estimate bos=%p, tos=%p\n",
  	 __pthread_initial_thread_bos, __pthread_initial_thread_tos);
#endif

  /* Setup pipe to communicate with thread manager */
  if (pipe(manager_pipe) == -1) {
    free(__pthread_manager_thread_bos);
    return -1;
  }
  /* Start the thread manager */
  pid = 0;
#ifdef USE_TLS
  if (__linuxthreads_initial_report_events != 0)
    THREAD_SETMEM (((pthread_descr) NULL), p_report_events,
		   __linuxthreads_initial_report_events);
  report_events = THREAD_GETMEM (((pthread_descr) NULL), p_report_events);
#else
  if (__linuxthreads_initial_report_events != 0)
    __pthread_initial_thread.p_report_events
      = __linuxthreads_initial_report_events;
  report_events = __pthread_initial_thread.p_report_events;
#endif
  if (__builtin_expect (report_events, 0))
    {
      /* It's a bit more complicated.  We have to report the creation of
	 the manager thread.  */
      int idx = __td_eventword (TD_CREATE);
      uint32_t mask = __td_eventmask (TD_CREATE);

      if ((mask & (__pthread_threads_events.event_bits[idx]
		   | __pthread_initial_thread.p_eventbuf.eventmask.event_bits[idx]))
	  != 0)
	{

	 __pthread_lock(__pthread_manager_thread.p_lock, NULL);

	  pid = clone(__pthread_manager_event,
			(void **) __pthread_manager_thread_tos,
			CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
			(void *)(long)manager_pipe[0]);

	  if (pid != -1)
	    {
	      /* Now fill in the information about the new thread in
	         the newly created thread's data structure.  We cannot let
	         the new thread do this since we don't know whether it was
	         already scheduled when we send the event.  */
	      __pthread_manager_thread.p_eventbuf.eventdata =
		  &__pthread_manager_thread;
	      __pthread_manager_thread.p_eventbuf.eventnum = TD_CREATE;
	      __pthread_last_event = &__pthread_manager_thread;
	      __pthread_manager_thread.p_tid = 2* PTHREAD_THREADS_MAX + 1;
	      __pthread_manager_thread.p_pid = pid;

	      /* Now call the function which signals the event.  */
	      __linuxthreads_create_event ();
	    }
	  /* Now restart the thread.  */
	  __pthread_unlock(__pthread_manager_thread.p_lock);
	}
    }

  if (pid == 0) {
    pid = clone(__pthread_manager, (void **) __pthread_manager_thread_tos,
		  CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
		  (void *)(long)manager_pipe[0]);
  }
  if (pid == -1) {
    free(__pthread_manager_thread_bos);
    __libc_close(manager_pipe[0]);
    __libc_close(manager_pipe[1]);
    return -1;
  }
  __pthread_manager_request = manager_pipe[1]; /* writing end */
  __pthread_manager_reader = manager_pipe[0]; /* reading end */
  __pthread_manager_thread.p_tid = 2* PTHREAD_THREADS_MAX + 1;
  __pthread_manager_thread.p_pid = pid;

  /* Make gdb aware of new thread manager */
  if (__pthread_threads_debug && __pthread_sig_debug > 0)
    {
      raise(__pthread_sig_debug);
      /* We suspend ourself and gdb will wake us up when it is
	 ready to handle us. */
      __pthread_wait_for_restart_signal(thread_self());
    }
  /* Synchronize debugging of the thread manager */
PDEBUG("send REQ_DEBUG to manager thread\n");
  request.req_kind = REQ_DEBUG;
  TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
	      (char *) &request, sizeof(request)));
  return 0;
}

/* Thread creation */

int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
			 void * (*start_routine)(void *), void *arg)
{
  pthread_descr self = thread_self();
  struct pthread_request request;
  if (__pthread_manager_request < 0) {
    if (__pthread_initialize_manager() < 0) return EAGAIN;
  }
  request.req_thread = self;
  request.req_kind = REQ_CREATE;
  request.req_args.create.attr = attr;
  request.req_args.create.fn = start_routine;
  request.req_args.create.arg = arg;
  sigprocmask(SIG_SETMASK, (const sigset_t *) NULL,
              &request.req_args.create.mask);
  PDEBUG("write REQ_CREATE to manager thread\n");
  TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
	      (char *) &request, sizeof(request)));
PDEBUG("before suspend(self)\n");
  suspend(self);
PDEBUG("after suspend(self)\n");
  if (THREAD_GETMEM(self, p_retcode) == 0)
    *thread = (pthread_t) THREAD_GETMEM(self, p_retval);
  return THREAD_GETMEM(self, p_retcode);
}

/* Simple operations on thread identifiers */

pthread_t pthread_self(void)
{
  pthread_descr self = thread_self();
  return THREAD_GETMEM(self, p_tid);
}

int pthread_equal(pthread_t thread1, pthread_t thread2)
{
  return thread1 == thread2;
}

/* Helper function for thread_self in the case of user-provided stacks */

#ifndef THREAD_SELF

pthread_descr __pthread_find_self()
{
  char * sp = CURRENT_STACK_FRAME;
  pthread_handle h;

  /* __pthread_handles[0] is the initial thread, __pthread_handles[1] is
     the manager threads handled specially in thread_self(), so start at 2 */
  h = __pthread_handles + 2;
  while (! (sp <= (char *) h->h_descr && sp >= h->h_bottom)) h++;

#ifdef DEBUG_PT
  if (h->h_descr == NULL) {
      printf("*** "__FUNCTION__" ERROR descriptor is NULL!!!!! ***\n\n");
      _exit(1);
  }
#endif

  return h->h_descr;
}
#else

static pthread_descr thread_self_stack(void)
{
    char *sp = CURRENT_STACK_FRAME;
    pthread_handle h;

    if (sp >= __pthread_manager_thread_bos && sp < __pthread_manager_thread_tos)
	return manager_thread;
    h = __pthread_handles + 2;
# ifdef USE_TLS
    while (h->h_descr == NULL
	    || ! (sp <= (char *) h->h_descr->p_stackaddr && sp >= h->h_bottom))
	h++;
# else
    while (! (sp <= (char *) h->h_descr && sp >= h->h_bottom))
	h++;
# endif
    return h->h_descr;
}

#endif

/* Thread scheduling */

int pthread_setschedparam(pthread_t thread, int policy,
                          const struct sched_param *param)
{
  pthread_handle handle = thread_handle(thread);
  pthread_descr th;

  __pthread_lock(&handle->h_lock, NULL);
  if (invalid_handle(handle, thread)) {
    __pthread_unlock(&handle->h_lock);
    return ESRCH;
  }
  th = handle->h_descr;
  if (sched_setscheduler(th->p_pid, policy, param) == -1) {
    __pthread_unlock(&handle->h_lock);
    return errno;
  }
  th->p_priority = policy == SCHED_OTHER ? 0 : param->sched_priority;
  __pthread_unlock(&handle->h_lock);
  if (__pthread_manager_request >= 0)
    __pthread_manager_adjust_prio(th->p_priority);
  return 0;
}

int pthread_getschedparam(pthread_t thread, int *policy,
                          struct sched_param *param)
{
  pthread_handle handle = thread_handle(thread);
  int pid, pol;

  __pthread_lock(&handle->h_lock, NULL);
  if (invalid_handle(handle, thread)) {
    __pthread_unlock(&handle->h_lock);
    return ESRCH;
  }
  pid = handle->h_descr->p_pid;
  __pthread_unlock(&handle->h_lock);
  pol = sched_getscheduler(pid);
  if (pol == -1) return errno;
  if (sched_getparam(pid, param) == -1) return errno;
  *policy = pol;
  return 0;
}

/* Process-wide exit() request */

static void pthread_onexit_process(int retcode, void *arg)
{
    struct pthread_request request;
    pthread_descr self = thread_self();

    if (__pthread_manager_request >= 0) {
	request.req_thread = self;
	request.req_kind = REQ_PROCESS_EXIT;
	request.req_args.exit.code = retcode;
	TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
		    (char *) &request, sizeof(request)));
	suspend(self);
	/* Main thread should accumulate times for thread manager and its
	   children, so that timings for main thread account for all threads. */
	if (self == __pthread_main_thread) {
	    waitpid(__pthread_manager_thread.p_pid, NULL, __WCLONE);
	    /* Since all threads have been asynchronously terminated
	     * (possibly holding locks), free cannot be used any more.  */
	    __pthread_manager_thread_bos = __pthread_manager_thread_tos = NULL;
	}
    }
}

/* The handler for the RESTART signal just records the signal received
   in the thread descriptor, and optionally performs a siglongjmp
   (for pthread_cond_timedwait). */

static void pthread_handle_sigrestart(int sig)
{
    pthread_descr self = thread_self();
    THREAD_SETMEM(self, p_signal, sig);
    if (THREAD_GETMEM(self, p_signal_jmp) != NULL)
	siglongjmp(*THREAD_GETMEM(self, p_signal_jmp), 1);
}

/* The handler for the CANCEL signal checks for cancellation
   (in asynchronous mode), for process-wide exit and exec requests.
   For the thread manager thread, redirect the signal to
   __pthread_manager_sighandler. */

static void pthread_handle_sigcancel(int sig)
{
  pthread_descr self = thread_self();