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https://gitlab.torproject.org/tpo/core/tor.git
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9cf335c9a5
Note that the workqueue code does *not* go here: it is logically at a higher level, since it needs to use libevent and the networking stack.
110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
/* Copyright (c) 2003-2004, Roger Dingledine
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* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
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* Copyright (c) 2007-2018, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/**
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* \file compat_threads.c
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*
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* \brief Cross-platform threading and inter-thread communication logic.
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* (Platform-specific parts are written in the other compat_*threads
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* modules.)
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*/
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#include "orconfig.h"
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#include <stdlib.h>
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#include "lib/thread/threads.h"
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#include "lib/log/torlog.h"
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#include "lib/log/util_bug.h"
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/** Allocate and return a new condition variable. */
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tor_cond_t *
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tor_cond_new(void)
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{
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tor_cond_t *cond = tor_malloc(sizeof(tor_cond_t));
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if (BUG(tor_cond_init(cond)<0))
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tor_free(cond); // LCOV_EXCL_LINE
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return cond;
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}
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/** Free all storage held in <b>c</b>. */
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void
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tor_cond_free_(tor_cond_t *c)
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{
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if (!c)
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return;
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tor_cond_uninit(c);
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tor_free(c);
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}
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/** Identity of the "main" thread */
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static unsigned long main_thread_id = -1;
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/** Start considering the current thread to be the 'main thread'. This has
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* no effect on anything besides in_main_thread(). */
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void
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set_main_thread(void)
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{
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main_thread_id = tor_get_thread_id();
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}
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/** Return true iff called from the main thread. */
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int
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in_main_thread(void)
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{
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return main_thread_id == tor_get_thread_id();
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}
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#ifndef HAVE_STDATOMIC_H
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/** Initialize a new atomic counter with the value 0 */
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void
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atomic_counter_init(atomic_counter_t *counter)
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{
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memset(counter, 0, sizeof(*counter));
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tor_mutex_init_nonrecursive(&counter->mutex);
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}
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/** Clean up all resources held by an atomic counter. */
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void
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atomic_counter_destroy(atomic_counter_t *counter)
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{
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tor_mutex_uninit(&counter->mutex);
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memset(counter, 0, sizeof(*counter));
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}
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/** Add a value to an atomic counter. */
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void
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atomic_counter_add(atomic_counter_t *counter, size_t add)
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{
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tor_mutex_acquire(&counter->mutex);
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counter->val += add;
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tor_mutex_release(&counter->mutex);
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}
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/** Subtract a value from an atomic counter. */
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void
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atomic_counter_sub(atomic_counter_t *counter, size_t sub)
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{
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// this relies on unsigned overflow, but that's fine.
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atomic_counter_add(counter, -sub);
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}
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/** Return the current value of an atomic counter */
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size_t
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atomic_counter_get(atomic_counter_t *counter)
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{
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size_t val;
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tor_mutex_acquire(&counter->mutex);
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val = counter->val;
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tor_mutex_release(&counter->mutex);
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return val;
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}
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/** Replace the value of an atomic counter; return the old one. */
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size_t
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atomic_counter_exchange(atomic_counter_t *counter, size_t newval)
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{
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size_t oldval;
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tor_mutex_acquire(&counter->mutex);
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oldval = counter->val;
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counter->val = newval;
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tor_mutex_release(&counter->mutex);
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return oldval;
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}
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#endif /* !defined(HAVE_STDATOMIC_H) */
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