/** Launch threads until we have <b>n</b>. */
static int
threadpool_start_threads(threadpool_t *pool, int n)
{
if (n < 0)
return -1;
if (n > MAX_THREADS)
n = MAX_THREADS;
tor_mutex_acquire(&pool->lock);
if (pool->n_threads < n)
pool->threads = tor_reallocarray(pool->threads,
sizeof(workerthread_t*), n);
while (pool->n_threads < n) {
void *state = pool->new_thread_state_fn(pool->new_thread_state_arg);
workerthread_t *thr = workerthread_new(state, pool, pool->reply_queue);
if (!thr) {
tor_mutex_release(&pool->lock);
return -1;
}
thr->index = pool->n_threads;
pool->threads[pool->n_threads++] = thr;
}
tor_mutex_release(&pool->lock);
return 0;
}
/**
* Process all pending replies on a reply queue. The main thread should call
* this function every time the socket returned by replyqueue_get_socket() is
* readable.
*/
void
replyqueue_process(replyqueue_t *queue)
{
if (queue->alert.drain_fn(queue->alert.read_fd) < 0) {
static ratelim_t warn_limit = RATELIM_INIT(7200);
log_fn_ratelim(&warn_limit, LOG_WARN, LD_GENERAL,
"Failure from drain_fd");
}
tor_mutex_acquire(&queue->lock);
while (!TOR_TAILQ_EMPTY(&queue->answers)) {
/* lock must be held at this point.*/
workqueue_entry_t *work = TOR_TAILQ_FIRST(&queue->answers);
TOR_TAILQ_REMOVE(&queue->answers, work, next_work);
tor_mutex_release(&queue->lock);
work->on_pool = NULL;
work->reply_fn(work->arg);
workqueue_entry_free(work);
tor_mutex_acquire(&queue->lock);
}
tor_mutex_release(&queue->lock);
}
/** Launch threads until we have <b>n</b>. */
static int
threadpool_start_threads(threadpool_t *pool, int n)
{
if (BUG(n < 0))
return -1; // LCOV_EXCL_LINE
if (n > MAX_THREADS)
n = MAX_THREADS;
tor_mutex_acquire(&pool->lock);
if (pool->n_threads < n)
pool->threads = tor_reallocarray(pool->threads,
sizeof(workerthread_t*), n);
while (pool->n_threads < n) {
void *state = pool->new_thread_state_fn(pool->new_thread_state_arg);
workerthread_t *thr = workerthread_new(state, pool, pool->reply_queue);
if (!thr) {
//LCOV_EXCL_START
tor_assert_nonfatal_unreached();
pool->free_thread_state_fn(state);
tor_mutex_release(&pool->lock);
return -1;
//LCOV_EXCL_STOP
}
thr->index = pool->n_threads;
pool->threads[pool->n_threads++] = thr;
}
tor_mutex_release(&pool->lock);
return 0;
}
static void
cv_test_thr_fn_(void *arg)
{
cv_testinfo_t *i = arg;
int tid, r;
tor_mutex_acquire(i->mutex);
tid = i->n_threads++;
tor_mutex_release(i->mutex);
(void) tid;
tor_mutex_acquire(i->mutex);
while (1) {
if (i->addend) {
i->value += i->addend;
i->addend = 0;
}
if (i->shutdown) {
++i->n_shutdown;
i->shutdown = 0;
tor_mutex_release(i->mutex);
spawn_exit();
}
r = tor_cond_wait(i->cond, i->mutex, i->tv);
++i->n_wakeups;
if (r == 1) {
++i->n_timeouts;
tor_mutex_release(i->mutex);
spawn_exit();
}
}
}
/**
* Main function for the worker thread.
*/
static void
worker_thread_main(void *thread_)
{
workerthread_t *thread = thread_;
threadpool_t *pool = thread->in_pool;
workqueue_entry_t *work;
workqueue_reply_t result;
tor_mutex_acquire(&pool->lock);
while (1) {
/* lock must be held at this point. */
while (worker_thread_has_work(thread)) {
/* lock must be held at this point. */
if (thread->in_pool->generation != thread->generation) {
void *arg = thread->in_pool->update_args[thread->index];
thread->in_pool->update_args[thread->index] = NULL;
workqueue_reply_t (*update_fn)(void*,void*) =
thread->in_pool->update_fn;
thread->generation = thread->in_pool->generation;
tor_mutex_release(&pool->lock);
workqueue_reply_t r = update_fn(thread->state, arg);
if (r != WQ_RPL_REPLY) {
return;
}
tor_mutex_acquire(&pool->lock);
continue;
}
work = TOR_TAILQ_FIRST(&pool->work);
TOR_TAILQ_REMOVE(&pool->work, work, next_work);
work->pending = 0;
tor_mutex_release(&pool->lock);
/* We run the work function without holding the thread lock. This
* is the main thread's first opportunity to give us more work. */
result = work->fn(thread->state, work->arg);
/* Queue the reply for the main thread. */
queue_reply(thread->reply_queue, work);
/* We may need to exit the thread. */
if (result != WQ_RPL_REPLY) {
return;
}
tor_mutex_acquire(&pool->lock);
}
/* At this point the lock is held, and there is no work in this thread's
* queue. */
/* TODO: support an idle-function */
/* Okay. Now, wait till somebody has work for us. */
if (tor_cond_wait(&pool->condition, &pool->lock, NULL) < 0) {
log_warn(LD_GENERAL, "Fail tor_cond_wait.");
}
}
}
static void
test_threads_conditionvar(void *arg)
{
cv_testinfo_t *ti=NULL;
const struct timeval msec100 = { 0, 100*1000 };
const int timeout = !strcmp(arg, "tv");
ti = cv_testinfo_new();
if (timeout) {
ti->tv = &msec100;
}
spawn_func(cv_test_thr_fn_, ti);
spawn_func(cv_test_thr_fn_, ti);
spawn_func(cv_test_thr_fn_, ti);
spawn_func(cv_test_thr_fn_, ti);
tor_mutex_acquire(ti->mutex);
ti->addend = 7;
ti->shutdown = 1;
tor_cond_signal_one(ti->cond);
tor_mutex_release(ti->mutex);
#define SPIN() \
while (1) { \
tor_mutex_acquire(ti->mutex); \
if (ti->addend == 0) { \
break; \
} \
tor_mutex_release(ti->mutex); \
}
SPIN();
ti->addend = 30;
ti->shutdown = 1;
tor_cond_signal_all(ti->cond);
tor_mutex_release(ti->mutex);
SPIN();
ti->addend = 1000;
if (! timeout) ti->shutdown = 1;
tor_cond_signal_one(ti->cond);
tor_mutex_release(ti->mutex);
SPIN();
ti->addend = 300;
if (! timeout) ti->shutdown = 1;
tor_cond_signal_all(ti->cond);
tor_mutex_release(ti->mutex);
SPIN();
tor_mutex_release(ti->mutex);
tt_int_op(ti->value, ==, 1337);
if (!timeout) {
tt_int_op(ti->n_shutdown, ==, 4);
} else {
/** Log a message <b>msg</b> at <b>severity</b> in <b>domain</b>, and follow
* that with a backtrace log. */
void
log_backtrace(int severity, int domain, const char *msg)
{
int depth;
char **symbols;
int i;
tor_mutex_acquire(&cb_buf_mutex);
depth = backtrace(cb_buf, MAX_DEPTH);
symbols = backtrace_symbols(cb_buf, depth);
tor_log(severity, domain, "%s. Stack trace:", msg);
if (!symbols) {
tor_log(severity, domain, " Unable to generate backtrace.");
goto done;
}
for (i=0; i < depth; ++i) {
tor_log(severity, domain, " %s", symbols[i]);
}
free(symbols);
done:
tor_mutex_release(&cb_buf_mutex);
}
/** Log a message <b>msg</b> at <b>severity</b> in <b>domain</b>, and follow
* that with a backtrace log. */
void
log_backtrace(int severity, int domain, const char *msg)
{
size_t depth;
char **symbols;
size_t i;
tor_mutex_acquire(&cb_buf_mutex);
depth = backtrace(cb_buf, MAX_DEPTH);
symbols = backtrace_symbols(cb_buf, (int)depth);
tor_log(severity, domain, "%s. Stack trace:", msg);
if (!symbols) {
/* LCOV_EXCL_START -- we can't provoke this. */
tor_log(severity, domain, " Unable to generate backtrace.");
goto done;
/* LCOV_EXCL_STOP */
}
for (i=0; i < depth; ++i) {
tor_log(severity, domain, " %s", symbols[i]);
}
raw_free(symbols);
done:
tor_mutex_release(&cb_buf_mutex);
}
static void
replysock_readable_cb(tor_socket_t sock, short what, void *arg)
{
threadpool_t *tp = arg;
replyqueue_t *rq = threadpool_get_replyqueue(tp);
int old_r = n_received;
(void) sock;
(void) what;
replyqueue_process(rq);
if (old_r == n_received)
return;
if (opt_verbose) {
printf("%d / %d", n_received, n_sent);
if (opt_n_cancel)
printf(" (%d cancelled, %d uncancellable)",
n_successful_cancel, n_failed_cancel);
puts("");
}
#ifdef TRACK_RESPONSES
tor_mutex_acquire(&bitmap_mutex);
for (i = 0; i < opt_n_items; ++i) {
if (bitarray_is_set(received, i))
putc('o', stdout);
else if (bitarray_is_set(handled, i))
putc('!', stdout);
else
putc('.', stdout);
}
puts("");
tor_mutex_release(&bitmap_mutex);
#endif
if (n_sent - (n_received+n_successful_cancel) < opt_n_lowwater) {
int n_to_send = n_received + opt_n_inflight - n_sent;
if (n_to_send > opt_n_items - n_sent)
n_to_send = opt_n_items - n_sent;
add_n_work_items(tp, n_to_send);
}
if (shutting_down == 0 &&
n_received+n_successful_cancel == n_sent &&
n_sent >= opt_n_items) {
shutting_down = 1;
threadpool_queue_update(tp, NULL,
workqueue_do_shutdown, NULL, NULL);
// Anything we add after starting the shutdown must not be executed.
threadpool_queue_work(tp, workqueue_shutdown_error,
handle_reply_shutdown, NULL);
{
struct timeval limit = { 2, 0 };
tor_event_base_loopexit(tor_libevent_get_base(), &limit);
}
}
}
/** Helper function for threading unit tests: This function runs in a
* subthread. It grabs its own mutex (start1 or start2) to make sure that it
* should start, then it repeatedly alters _test_thread_strmap protected by
* thread_test_mutex_. */
static void
thread_test_func_(void* _s)
{
char *s = _s;
int i, *count;
tor_mutex_t *m;
char buf[64];
char **cp;
if (!strcmp(s, "thread 1")) {
m = thread_test_start1_;
cp = &thread1_name_;
count = &t1_count;
thread_fn_tid1 = tor_get_thread_id();
} else {
m = thread_test_start2_;
cp = &thread2_name_;
count = &t2_count;
thread_fn_tid2 = tor_get_thread_id();
}
tor_snprintf(buf, sizeof(buf), "%lu", tor_get_thread_id());
*cp = tor_strdup(buf);
tor_mutex_acquire(m);
for (i=0; i<10000; ++i) {
tor_mutex_acquire(thread_test_mutex_);
strmap_set(thread_test_strmap_, "last to run", *cp);
++*count;
tor_mutex_release(thread_test_mutex_);
}
tor_mutex_acquire(thread_test_mutex_);
strmap_set(thread_test_strmap_, s, *cp);
if (in_main_thread())
++thread_fns_failed;
tor_mutex_release(thread_test_mutex_);
tor_mutex_release(m);
spawn_exit();
}
static void
mark_handled(int serial)
{
#ifdef TRACK_RESPONSES
tor_mutex_acquire(&bitmap_mutex);
tor_assert(serial < handled_len);
tor_assert(! bitarray_is_set(handled, serial));
bitarray_set(handled, serial);
tor_mutex_release(&bitmap_mutex);
#else
(void)serial;
#endif
}
/** Put a reply on the reply queue. The reply must not currently be on
* any thread's work queue. */
static void
queue_reply(replyqueue_t *queue, workqueue_entry_t *work)
{
int was_empty;
tor_mutex_acquire(&queue->lock);
was_empty = TOR_TAILQ_EMPTY(&queue->answers);
TOR_TAILQ_INSERT_TAIL(&queue->answers, work, next_work);
tor_mutex_release(&queue->lock);
if (was_empty) {
if (queue->alert.alert_fn(queue->alert.write_fd) < 0) {
/* XXXX complain! */
}
}
}
/**
* Cancel a workqueue_entry_t that has been returned from
* threadpool_queue_work.
*
* You must not call this function on any work whose reply function has been
* executed in the main thread; that will cause undefined behavior (probably,
* a crash).
*
* If the work is cancelled, this function return the argument passed to the
* work function. It is the caller's responsibility to free this storage.
*
* This function will have no effect if the worker thread has already executed
* or begun to execute the work item. In that case, it will return NULL.
*/
void *
workqueue_entry_cancel(workqueue_entry_t *ent)
{
int cancelled = 0;
void *result = NULL;
tor_mutex_acquire(&ent->on_pool->lock);
if (ent->pending) {
TOR_TAILQ_REMOVE(&ent->on_pool->work, ent, next_work);
cancelled = 1;
result = ent->arg;
}
tor_mutex_release(&ent->on_pool->lock);
if (cancelled) {
workqueue_entry_free(ent);
}
return result;
}
/**
* Queue a copy of a work item for every thread in a pool. This can be used,
* for example, to tell the threads to update some parameter in their states.
*
* Arguments are as for <b>threadpool_queue_work</b>, except that the
* <b>arg</b> value is passed to <b>dup_fn</b> once per each thread to
* make a copy of it.
*
* UPDATE FUNCTIONS MUST BE IDEMPOTENT. We do not guarantee that every update
* will be run. If a new update is scheduled before the old update finishes
* running, then the new will replace the old in any threads that haven't run
* it yet.
*
* Return 0 on success, -1 on failure.
*/
int
threadpool_queue_update(threadpool_t *pool,
void *(*dup_fn)(void *),
int (*fn)(void *, void *),
void (*free_fn)(void *),
void *arg)
{
int i, n_threads;
void (*old_args_free_fn)(void *arg);
void **old_args;
void **new_args;
tor_mutex_acquire(&pool->lock);
n_threads = pool->n_threads;
old_args = pool->update_args;
old_args_free_fn = pool->free_update_arg_fn;
new_args = tor_calloc(n_threads, sizeof(void*));
for (i = 0; i < n_threads; ++i) {
if (dup_fn)
new_args[i] = dup_fn(arg);
else
new_args[i] = arg;
}
pool->update_args = new_args;
pool->free_update_arg_fn = free_fn;
pool->update_fn = fn;
++pool->generation;
tor_mutex_release(&pool->lock);
tor_cond_signal_all(&pool->condition);
if (old_args) {
for (i = 0; i < n_threads; ++i) {
if (old_args[i] && old_args_free_fn)
old_args_free_fn(old_args[i]);
}
tor_free(old_args);
}
return 0;
}
/**
* Queue an item of work for a thread in a thread pool. The function
* <b>fn</b> will be run in a worker thread, and will receive as arguments the
* thread's state object, and the provided object <b>arg</b>. It must return
* one of WQ_RPL_REPLY, WQ_RPL_ERROR, or WQ_RPL_SHUTDOWN.
*
* Regardless of its return value, the function <b>reply_fn</b> will later be
* run in the main thread when it invokes replyqueue_process(), and will
* receive as its argument the same <b>arg</b> object. It's the reply
* function's responsibility to free the work object.
*
* On success, return a workqueue_entry_t object that can be passed to
* workqueue_entry_cancel(). On failure, return NULL.
*
* Note that because each thread has its own work queue, work items may not
* be executed strictly in order.
*/
workqueue_entry_t *
threadpool_queue_work(threadpool_t *pool,
int (*fn)(void *, void *),
void (*reply_fn)(void *),
void *arg)
{
workqueue_entry_t *ent = workqueue_entry_new(fn, reply_fn, arg);
ent->on_pool = pool;
ent->pending = 1;
tor_mutex_acquire(&pool->lock);
TOR_TAILQ_INSERT_TAIL(&pool->work, ent, next_work);
tor_mutex_release(&pool->lock);
tor_cond_signal_one(&pool->condition);
return ent;
}
/** Run unit tests for threading logic. */
static void
test_threads_basic(void *arg)
{
char *s1 = NULL, *s2 = NULL;
int done = 0, timedout = 0;
time_t started;
#ifndef _WIN32
struct timeval tv;
tv.tv_sec=0;
tv.tv_usec=100*1000;
#endif
(void) arg;
set_main_thread();
thread_test_mutex_ = tor_mutex_new();
thread_test_start1_ = tor_mutex_new();
thread_test_start2_ = tor_mutex_new();
thread_test_strmap_ = strmap_new();
s1 = tor_strdup("thread 1");
s2 = tor_strdup("thread 2");
tor_mutex_acquire(thread_test_start1_);
tor_mutex_acquire(thread_test_start2_);
spawn_func(thread_test_func_, s1);
spawn_func(thread_test_func_, s2);
tor_mutex_release(thread_test_start2_);
tor_mutex_release(thread_test_start1_);
started = time(NULL);
while (!done) {
tor_mutex_acquire(thread_test_mutex_);
strmap_assert_ok(thread_test_strmap_);
if (strmap_get(thread_test_strmap_, "thread 1") &&
strmap_get(thread_test_strmap_, "thread 2")) {
done = 1;
} else if (time(NULL) > started + 150) {
timedout = done = 1;
}
tor_mutex_release(thread_test_mutex_);
#ifndef _WIN32
/* Prevent the main thread from starving the worker threads. */
select(0, NULL, NULL, NULL, &tv);
#endif
}
tor_mutex_acquire(thread_test_start1_);
tor_mutex_release(thread_test_start1_);
tor_mutex_acquire(thread_test_start2_);
tor_mutex_release(thread_test_start2_);
tor_mutex_free(thread_test_mutex_);
if (timedout) {
printf("\nTimed out: %d %d", t1_count, t2_count);
tt_assert(strmap_get(thread_test_strmap_, "thread 1"));
tt_assert(strmap_get(thread_test_strmap_, "thread 2"));
tt_assert(!timedout);
}
/* different thread IDs. */
tt_assert(strcmp(strmap_get(thread_test_strmap_, "thread 1"),
strmap_get(thread_test_strmap_, "thread 2")));
tt_assert(!strcmp(strmap_get(thread_test_strmap_, "thread 1"),
strmap_get(thread_test_strmap_, "last to run")) ||
!strcmp(strmap_get(thread_test_strmap_, "thread 2"),
strmap_get(thread_test_strmap_, "last to run")));
tt_int_op(thread_fns_failed, ==, 0);
tt_int_op(thread_fn_tid1, !=, thread_fn_tid2);
done:
tor_free(s1);
tor_free(s2);
tor_free(thread1_name_);
tor_free(thread2_name_);
if (thread_test_strmap_)
strmap_free(thread_test_strmap_, NULL);
if (thread_test_start1_)
tor_mutex_free(thread_test_start1_);
if (thread_test_start2_)
tor_mutex_free(thread_test_start2_);
}
