1 /* 2 * libusb synchronization on Microsoft Windows 3 * 4 * Copyright (C) 2010 Michael Plante <michael.plante (at) 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 } 207 208
