libusb/os/threads_windows.c

   1 /*
   2  * libusbx synchronization on Microsoft Windows
   3  *
   4  * Copyright © 2010 Michael Plante <michael.plante@gmail.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <config.h>
  22 #include <objbase.h>
  23 #include <errno.h>
  24 #include <stdarg.h>
  25
  26 #include "libusbi.h"
  27
  28
  29 int usbi_mutex_init(usbi_mutex_t *mutex,
  30                                         const usbi_mutexattr_t *attr) {
  31         if(! mutex) return ((errno=EINVAL));
  32         *mutex = CreateMutex(NULL, FALSE, NULL);
  33         if(!*mutex) return ((errno=ENOMEM));
  34         return 0;
  35 }
  36 int usbi_mutex_destroy(usbi_mutex_t *mutex) {
  37         // It is not clear if CloseHandle failure is due to failure to unlock.
  38         //   If so, this should be errno=EBUSY.
  39         if(!mutex || !CloseHandle(*mutex)) return ((errno=EINVAL));
  40         *mutex = NULL;
  41         return 0;
  42 }
  43 int usbi_mutex_trylock(usbi_mutex_t *mutex) {
  44         DWORD result;
  45         if(!mutex) return ((errno=EINVAL));
  46         result = WaitForSingleObject(*mutex, 0);
  47         if(result == WAIT_OBJECT_0 || result == WAIT_ABANDONED)
  48                 return 0; // acquired (ToDo: check that abandoned is ok)
  49         if(result == WAIT_TIMEOUT)
  50                 return ((errno=EBUSY));
  51         return ((errno=EINVAL)); // don't know how this would happen
  52                                                          //   so don't know proper errno
  53 }
  54 int usbi_mutex_lock(usbi_mutex_t *mutex) {
  55         DWORD result;
  56         if(!mutex) return ((errno=EINVAL));
  57         result = WaitForSingleObject(*mutex, INFINITE);
  58         if(result == WAIT_OBJECT_0 || result == WAIT_ABANDONED)
  59                 return 0; // acquired (ToDo: check that abandoned is ok)
  60         return ((errno=EINVAL)); // don't know how this would happen
  61                                                          //   so don't know proper errno
  62 }
  63 int usbi_mutex_unlock(usbi_mutex_t *mutex) {
  64         if(!mutex)                return ((errno=EINVAL));
  65         if(!ReleaseMutex(*mutex)) return ((errno=EPERM ));
  66         return 0;
  67 }
  68
  69 int usbi_mutex_static_lock(usbi_mutex_static_t *mutex) {
  70         if(!mutex)               return ((errno=EINVAL));
  71         while (InterlockedExchange((LONG *)mutex, 1) == 1) {
  72                 SleepEx(0, TRUE);
  73         }
  74         return 0;
  75 }
  76 int usbi_mutex_static_unlock(usbi_mutex_static_t *mutex) {
  77         if(!mutex)               return ((errno=EINVAL));
  78         *mutex = 0;
  79         return 0;
  80 }
  81
  82
  83
  84 int usbi_cond_init(usbi_cond_t *cond,
  85                                    const usbi_condattr_t *attr) {
  86         if(!cond)           return ((errno=EINVAL));
  87         list_init(&cond->waiters    );
  88         list_init(&cond->not_waiting);
  89         return 0;
  90 }
  91 int usbi_cond_destroy(usbi_cond_t *cond) {
  92         // This assumes no one is using this anymore.  The check MAY NOT BE safe.
  93         struct usbi_cond_perthread *pos, *prev_pos = NULL;
  94         if(!cond) return ((errno=EINVAL));
  95         if(!list_empty(&cond->waiters)) return ((errno=EBUSY )); // (!see above!)
  96         list_for_each_entry(pos, &cond->not_waiting, list, struct usbi_cond_perthread) {
  97                 free(prev_pos);
  98                 list_del(&pos->list);
  99                 prev_pos = pos;
 100         }
 101         free(prev_pos);
 102
 103         return 0;
 104 }
 105
 106 int usbi_cond_broadcast(usbi_cond_t *cond) {
 107         // Assumes mutex is locked; this is not in keeping with POSIX spec, but
 108         //   libusb does this anyway, so we simplify by not adding more sync
 109         //   primitives to the CV definition!
 110         int fail = 0;
 111         struct usbi_cond_perthread *pos;
 112         if(!cond)                      return ((errno=EINVAL));
 113         list_for_each_entry(pos, &cond->waiters, list, struct usbi_cond_perthread) {
 114                 if(!SetEvent(pos->event))
 115                         fail = 1;
 116         }
 117         // The wait function will remove its respective item from the list.
 118         return fail ? ((errno=EINVAL)) : 0;
 119 }
 120 int usbi_cond_signal(usbi_cond_t *cond) {
 121         // Assumes mutex is locked; this is not in keeping with POSIX spec, but
 122         //   libusb does this anyway, so we simplify by not adding more sync
 123         //   primitives to the CV definition!
 124         struct usbi_cond_perthread *pos;
 125         if(!cond)                      return ((errno=EINVAL));
 126         if(list_empty(&cond->waiters)) return 0; // no one to wakeup.
 127         pos = list_entry(&cond->waiters.next, struct usbi_cond_perthread, list);
 128         // The wait function will remove its respective item from the list.
 129         return SetEvent(pos->event) ? 0 : ((errno=EINVAL));
 130 }
 131 static int __inline usbi_cond_intwait(usbi_cond_t *cond,
 132                                                                           usbi_mutex_t *mutex,
 133                                                                           DWORD timeout_ms) {
 134         struct usbi_cond_perthread *pos;
 135         int found = 0, r;
 136         DWORD r2,tid = GetCurrentThreadId();
 137         if(!cond || !mutex) return ((errno=EINVAL));
 138         list_for_each_entry(pos, &cond->not_waiting, list, struct usbi_cond_perthread) {
 139                 if(tid == pos->tid) {
 140                         found = 1;
 141                         break;
 142                 }
 143         }
 144         if(!found) {
 145                 pos      = (struct usbi_cond_perthread*) calloc(1, sizeof(struct usbi_cond_perthread));
 146                 if(!pos) return ((errno=ENOMEM)); // This errno is not POSIX-allowed.
 147                 pos->tid = tid;
 148                 pos->event = CreateEvent(NULL, FALSE, FALSE, NULL); // auto-reset.
 149                 if(!pos->event) {
 150                         free(pos);
 151                         return      ((errno=ENOMEM));
 152                 }
 153                 list_add(&pos->list, &cond->not_waiting);
 154         }
 155
 156         list_del(&pos->list); // remove from not_waiting list.
 157         list_add(&pos->list, &cond->waiters);
 158
 159         r  = usbi_mutex_unlock(mutex);
 160         if(r) return r;
 161         r2 = WaitForSingleObject(pos->event, timeout_ms);
 162         r  = usbi_mutex_lock(mutex);
 163         if(r) return r;
 164
 165         list_del(&pos->list);
 166         list_add(&pos->list, &cond->not_waiting);
 167
 168         if(r2 == WAIT_TIMEOUT) return ((errno=ETIMEDOUT));
 169
 170         return 0;
 171 }
 172 // N.B.: usbi_cond_*wait() can also return ENOMEM, even though pthread_cond_*wait cannot!
 173 int usbi_cond_wait(usbi_cond_t *cond, usbi_mutex_t *mutex) {
 174         return usbi_cond_intwait(cond, mutex, INFINITE);
 175 }
 176 int usbi_cond_timedwait(usbi_cond_t *cond,
 177                                                 usbi_mutex_t *mutex,
 178                                                 const struct timespec *abstime) {
 179         FILETIME filetime;
 180         ULARGE_INTEGER rtime;
 181         struct timeval targ_time, cur_time, delta_time;
 182         struct timespec cur_time_ns;
 183         DWORD millis;
 184         extern const uint64_t epoch_time;
 185
 186         GetSystemTimeAsFileTime(&filetime);
 187         rtime.LowPart   = filetime.dwLowDateTime;
 188         rtime.HighPart  = filetime.dwHighDateTime;
 189         rtime.QuadPart -= epoch_time;
 190         cur_time_ns.tv_sec = (long)(rtime.QuadPart / 10000000);
 191         cur_time_ns.tv_nsec = (long)((rtime.QuadPart % 10000000)*100);
 192         TIMESPEC_TO_TIMEVAL(&cur_time, &cur_time_ns);
 193
 194         TIMESPEC_TO_TIMEVAL(&targ_time, abstime);
 195         timersub(&targ_time, &cur_time, &delta_time);
 196         if(delta_time.tv_sec < 0) // abstime already passed?
 197                 millis = 0;
 198         else {
 199                 millis  = delta_time.tv_usec/1000;
 200                 millis += delta_time.tv_sec *1000;
 201                 if (delta_time.tv_usec % 1000) // round up to next millisecond
 202                         millis++;
 203         }
 204
 205         return usbi_cond_intwait(cond, mutex, millis);
 206 }