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
29int 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}
36int 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}
43int 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}
54int 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}
63int 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
69int 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}
76int 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
84int 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}
91int 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
106int 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}
120int 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}
131static 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!
173int usbi_cond_wait(usbi_cond_t *cond, usbi_mutex_t *mutex) {
174	return usbi_cond_intwait(cond, mutex, INFINITE);
175}
176int 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