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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include "pthread_internal.h"
     30 
     31 #include "private/bionic_futex.h"
     32 #include "private/bionic_tls.h"
     33 #include "private/ScopedPthreadMutexLocker.h"
     34 
     35 pthread_internal_t* g_thread_list = NULL;
     36 pthread_mutex_t g_thread_list_lock = PTHREAD_MUTEX_INITIALIZER;
     37 
     38 void _pthread_internal_remove_locked(pthread_internal_t* thread) {
     39   if (thread->next != NULL) {
     40     thread->next->prev = thread->prev;
     41   }
     42   if (thread->prev != NULL) {
     43     thread->prev->next = thread->next;
     44   } else {
     45     g_thread_list = thread->next;
     46   }
     47 
     48   // The main thread is not heap-allocated. See __libc_init_tls for the declaration,
     49   // and __libc_init_common for the point where it's added to the thread list.
     50   if ((thread->attr.flags & PTHREAD_ATTR_FLAG_MAIN_THREAD) == 0) {
     51     free(thread);
     52   }
     53 }
     54 
     55 void _pthread_internal_add(pthread_internal_t* thread) {
     56   ScopedPthreadMutexLocker locker(&g_thread_list_lock);
     57 
     58   // We insert at the head.
     59   thread->next = g_thread_list;
     60   thread->prev = NULL;
     61   if (thread->next != NULL) {
     62     thread->next->prev = thread;
     63   }
     64   g_thread_list = thread;
     65 }
     66 
     67 pthread_internal_t* __get_thread(void) {
     68   return reinterpret_cast<pthread_internal_t*>(__get_tls()[TLS_SLOT_THREAD_ID]);
     69 }
     70 
     71 // Initialize 'ts' with the difference between 'abstime' and the current time
     72 // according to 'clock'. Returns -1 if abstime already expired, or 0 otherwise.
     73 int __timespec_from_absolute(timespec* ts, const timespec* abstime, clockid_t clock) {
     74   clock_gettime(clock, ts);
     75   ts->tv_sec  = abstime->tv_sec - ts->tv_sec;
     76   ts->tv_nsec = abstime->tv_nsec - ts->tv_nsec;
     77   if (ts->tv_nsec < 0) {
     78     ts->tv_sec--;
     79     ts->tv_nsec += 1000000000;
     80   }
     81   if ((ts->tv_nsec < 0) || (ts->tv_sec < 0)) {
     82     return -1;
     83   }
     84   return 0;
     85 }
     86