c/pthread_extra/pthread_user_data.c

   1 #define __PTHREAD_EXTRA_INTERNAL
   2
   3 #include <assert.h>
   4 #include <pthread.h>
   5 #include <pthread_extra.h>
   6
   7 //Static array with user data for all thread handles
   8 //TODO: perhaps use something more sophisticated like linked list?
   9 pthread_user_data_internal_t pthread_user_data[PTHREAD_XTHREADS_MAX+1] = {{.tid=PTHREAD_XNULL}};
  10 pthread_mutex_t pthread_user_data_mutex = PTHREAD_MUTEX_INITIALIZER;
  11
  12 int pthread_user_data_lock() {
  13         pthread_pause_disable();
  14         return pthread_mutex_lock(&pthread_user_data_mutex);
  15 }
  16
  17 int pthread_user_data_unlock() {
  18         pthread_mutex_unlock(&pthread_user_data_mutex);
  19         pthread_pause_enable();
  20         return 0;
  21 }
  22
  23 //Get pointer to internal record tied to specified thread
  24 pthread_user_data_internal_t* pthread_user_data_internal(pthread_t thread) {
  25         //Return NULL if requested thread handle is NULL
  26         if(pthread_equal(thread, PTHREAD_XNULL)) return NULL;
  27
  28         //Lock
  29         pthread_user_data_lock(); //TODO: maybe use R/W locking scheme?
  30
  31         //Find if the thread is already registered, add it if not
  32         //FIXME: detect overflow of array and cause assert fail!
  33         //FIXME: recycle slots of destroyed threads!!! signaled using pthread_user_data_remove();
  34         pthread_t i;
  35         for(i = 0; i<PTHREAD_XTHREADS_MAX; i++) {
  36                 if(pthread_equal(pthread_user_data[i].tid, PTHREAD_XNULL)) {
  37                         pthread_user_data[i+1].tid = PTHREAD_XNULL;
  38                         pthread_user_data[i].tid = thread;
  39                         break;
  40                 }
  41                 if(pthread_equal(pthread_user_data[i].tid, thread)) break;
  42         }
  43
  44         //UnLock
  45         pthread_user_data_unlock();
  46
  47         //Return pointer
  48         return &pthread_user_data[i];
  49 }
  50
  51 //Get pointer to user specified pointer of that thread
  52 void** pthread_user_data_ptr(pthread_t thread) {
  53         return &pthread_user_data_internal(thread)->usr;
  54 }
  55
  56 //Set user specified pointer for thread
  57 void pthread_user_data_set(pthread_t thread, void *usr) {
  58         *(pthread_user_data_ptr(thread)) = usr;
  59 }
  60
  61 //Get user specified pointer for thread
  62 void* pthread_user_data_get(pthread_t thread) {
  63         return *(pthread_user_data_ptr(thread));
  64 }
  65
  66 //Remove canceled thread from user data registry
  67 int pthread_user_data_remove(pthread_t thread) {
  68         //FIXME: not implemented yet!
  69         (void) thread;
  70         return 0;
  71 }
  72
  73 //User data cleanup handler to be registered with pthread_cleanup_push()
  74 void pthread_user_data_cleanup( void * arg ) {
  75         pthread_t t = (pthread_t)arg;
  76         assert(pthread_equal(t, pthread_self()) && "Pthread_self() is not working in cleanup context!");
  77         pthread_user_data_remove(t);
  78 }