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/*
* Copyright 2016 Garrett D'Amore <garrett@damore.org>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
/*
* This is more of a direct #include of a .c rather than .h file.
* But having it be a .h makes compiler rules work out properly. Do
* not include this more than once into your program, or you will
* get multiple symbols defined.
*/
/*
* POSIX synchronization (mutexes and condition variables). This uses
* pthreads.
*/
#include <pthread.h>
#include <time.h>
struct nni_mutex {
pthread_mutex_t mx;
};
struct nni_cond {
pthread_cond_t cv;
pthread_mutex_t *mx;
};
int
nni_mutex_create(nni_mutex_t *mp)
{
struct nni_mutex *m;
pthread_mutexattr_t attr;
int rv;
if ((m = nni_alloc(sizeof (*m))) == NULL) {
return (NNG_ENOMEM);
}
/* We ask for more error checking... */
if (pthread_mutexattr_init(&attr) != 0) {
nni_free(m, sizeof (*m));
return (NNG_ENOMEM);
}
if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK) != 0) {
nni_panic("pthread_mutexattr_settype failed");
}
rv = pthread_mutex_init(&m->mx, &attr);
if (pthread_mutexattr_destroy(&attr) != 0) {
nni_panic("pthread_mutexattr_destroy failed");
}
if (rv != 0) {
nni_free(m, sizeof (*m));
return (NNG_ENOMEM);
}
*mp = m;
return (0);
}
void
nni_mutex_destroy(nni_mutex_t m)
{
if (pthread_mutex_destroy(&m->mx) != 0) {
nni_panic("pthread_mutex_destroy failed");
}
/*
* If destroy fails for some reason, we can't really do
* anything about it. This would actually represent a programming
* bug, and the right thing to do here would be to panic.
*/
nni_free(m, sizeof (*m));
}
void
nni_mutex_enter(nni_mutex_t m)
{
if (pthread_mutex_lock(&m->mx) != 0) {
nni_panic("pthread_mutex_lock failed");
}
}
void
nni_mutex_exit(nni_mutex_t m)
{
if (pthread_mutex_unlock(&m->mx) != 0) {
nni_panic("pthread_mutex_unlock failed");
}
}
int
nni_mutex_tryenter(nni_mutex_t m)
{
if (pthread_mutex_trylock(&m->mx) != 0) {
return (NNG_EBUSY);
}
return (0);
}
int
cond_attr(pthread_condattr_t **attrpp)
{
#if defined(NNG_USE_GETTIMEOFDAY) || NNG_USE_CLOCKID == CLOCK_REALTIME
*attrpp = NULL;
return (0);
#else
/* In order to make this fast, avoid reinitializing attrs. */
static pthread_condattr_t attr;
static pthread_mutex_t mx = PTHREAD_MUTEX_INITIALIZER;
static int init = 0;
int rv;
/*
* For efficiency's sake, we try to reuse the same attr for the
* life of the library. This avoids many reallocations. Technically
* this means that we will leak the attr on exit(), but this is
* preferable to constantly allocating and reallocating it.
*/
if (init) {
*attrpp = &attr;
return (0);
}
(void) pthread_mutex_lock(&mx);
while (!init) {
if ((rv = pthread_condattr_init(&attr)) != 0) {
(void) pthread_mutex_unlock(&mx);
return (NNG_ENOMEM);
}
rv = pthread_condattr_setclock(&attr, NNG_USE_CLOCKID);
if (rv != 0) {
nni_panic("condattr_setclock: %s", strerror(rv));
}
init = 1;
}
(void) pthread_mutex_unlock(&mx);
*attrpp = &attr;
return (0);
#endif
}
int
nni_cond_create(nni_cond_t *cvp, nni_mutex_t mx)
{
/*
* By preference, we use a CLOCK_MONOTONIC version of condition
* variables, which insulates us from changes to the system time.
*/
struct nni_cond *c;
pthread_condattr_t *attrp;
int rv;
if ((rv = cond_attr(&attrp)) != 0) {
return (rv);
}
if ((c = nni_alloc(sizeof (*c))) == NULL) {
return (NNG_ENOMEM);
}
c->mx = &mx->mx;
if (pthread_cond_init(&c->cv, attrp) != 0) {
/* In theory could be EAGAIN, but handle like ENOMEM */
nni_free(c, sizeof (*c));
return (NNG_ENOMEM);
}
*cvp = c;
return (0);
}
void
nni_cond_destroy(nni_cond_t c)
{
if (pthread_cond_destroy(&c->cv) != 0) {
nni_panic("pthread_cond_destroy failed");
}
nni_free(c, sizeof (*c));
}
void
nni_cond_signal(nni_cond_t c)
{
if (pthread_cond_signal(&c->cv) != 0) {
nni_panic("pthread_cond_signal failed");
}
}
void
nni_cond_broadcast(nni_cond_t c)
{
if (pthread_cond_broadcast(&c->cv) != 0) {
nni_panic("pthread_cond_broadcast failed");
}
}
void
nni_cond_wait(nni_cond_t c)
{
if (pthread_cond_wait(&c->cv, c->mx) != 0) {
nni_panic("pthread_cond_wait failed");
}
}
int
nni_cond_timedwait(nni_cond_t c, uint64_t usec)
{
struct timespec ts;
int rv;
usec += nni_clock();
ts.tv_sec = usec / 1000000;
ts.tv_nsec = (usec % 10000) * 1000;
if ((rv = pthread_cond_timedwait(&c->cv, c->mx, &ts)) != 0) {
if (rv == ETIMEDOUT) {
return (NNG_ETIMEDOUT);
} else {
nni_panic("pthread_cond_timedwait returned %d", rv);
}
}
return (0);
}
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