1 /*
2 * libusb synchronization on Microsoft Windows
3 *
4 * Copyright (C) 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
usbi_mutex_init(usbi_mutex_t * mutex,const usbi_mutexattr_t * attr)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 }
usbi_mutex_destroy(usbi_mutex_t * mutex)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 }
usbi_mutex_trylock(usbi_mutex_t * mutex)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 }
usbi_mutex_lock(usbi_mutex_t * mutex)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 }
usbi_mutex_unlock(usbi_mutex_t * mutex)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
usbi_mutex_static_lock(usbi_mutex_static_t * mutex)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 }
usbi_mutex_static_unlock(usbi_mutex_static_t * mutex)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
usbi_cond_init(usbi_cond_t * cond,const usbi_condattr_t * attr)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 }
usbi_cond_destroy(usbi_cond_t * cond)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
usbi_cond_broadcast(usbi_cond_t * cond)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 }
usbi_cond_signal(usbi_cond_t * cond)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 }
usbi_cond_intwait(usbi_cond_t * cond,usbi_mutex_t * mutex,DWORD timeout_ms)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!
usbi_cond_wait(usbi_cond_t * cond,usbi_mutex_t * mutex)173 int usbi_cond_wait(usbi_cond_t *cond, usbi_mutex_t *mutex) {
174 return usbi_cond_intwait(cond, mutex, INFINITE);
175 }
usbi_cond_timedwait(usbi_cond_t * cond,usbi_mutex_t * mutex,const struct timespec * abstime)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