Commit c2f0d52b authored by Nick Mathewson's avatar Nick Mathewson 👁
Browse files

Split threading-related code out of compat.c

Also, re-enable the #if'd out condition-variable code.

Work queues are going to make us hack on all of this stuff a bit more
closely, so it might not be a terrible idea to make it easier to hack.
parent 518b0b3c
......@@ -393,6 +393,10 @@ fi
AC_SEARCH_LIBS(pthread_create, [pthread])
AC_SEARCH_LIBS(pthread_detach, [pthread])
AM_CONDITIONAL(THREADS_WIN32, test "$enable_threads" = "yes" && test "$bwin32" = "true")
AM_CONDITIONAL(THREADS_PTHREADS, test "$enable_threads" = "yes" && test "$bwin32" = "false")
AM_CONDITIONAL(THREADS_NONE, test "$enable_threads" != "yes")
dnl -------------------------------------------------------------------
dnl Check for functions before libevent, since libevent-1.2 apparently
dnl exports strlcpy without defining it in a header.
......
......@@ -2544,109 +2544,6 @@ get_uname(void)
* Process control
*/
#if defined(USE_PTHREADS)
/** Wraps a void (*)(void*) function and its argument so we can
* invoke them in a way pthreads would expect.
*/
typedef struct tor_pthread_data_t {
void (*func)(void *);
void *data;
} tor_pthread_data_t;
/** Given a tor_pthread_data_t <b>_data</b>, call _data-&gt;func(d-&gt;data)
* and free _data. Used to make sure we can call functions the way pthread
* expects. */
static void *
tor_pthread_helper_fn(void *_data)
{
tor_pthread_data_t *data = _data;
void (*func)(void*);
void *arg;
/* mask signals to worker threads to avoid SIGPIPE, etc */
sigset_t sigs;
/* We're in a subthread; don't handle any signals here. */
sigfillset(&sigs);
pthread_sigmask(SIG_SETMASK, &sigs, NULL);
func = data->func;
arg = data->data;
tor_free(_data);
func(arg);
return NULL;
}
/**
* A pthread attribute to make threads start detached.
*/
static pthread_attr_t attr_detached;
/** True iff we've called tor_threads_init() */
static int threads_initialized = 0;
#endif
/** Minimalist interface to run a void function in the background. On
* Unix calls fork, on win32 calls beginthread. Returns -1 on failure.
* func should not return, but rather should call spawn_exit.
*
* NOTE: if <b>data</b> is used, it should not be allocated on the stack,
* since in a multithreaded environment, there is no way to be sure that
* the caller's stack will still be around when the called function is
* running.
*/
int
spawn_func(void (*func)(void *), void *data)
{
#if defined(USE_WIN32_THREADS)
int rv;
rv = (int)_beginthread(func, 0, data);
if (rv == (int)-1)
return -1;
return 0;
#elif defined(USE_PTHREADS)
pthread_t thread;
tor_pthread_data_t *d;
if (PREDICT_UNLIKELY(!threads_initialized))
tor_threads_init();
d = tor_malloc(sizeof(tor_pthread_data_t));
d->data = data;
d->func = func;
if (pthread_create(&thread,&attr_detached,tor_pthread_helper_fn,d))
return -1;
return 0;
#else
pid_t pid;
pid = fork();
if (pid<0)
return -1;
if (pid==0) {
/* Child */
func(data);
tor_assert(0); /* Should never reach here. */
return 0; /* suppress "control-reaches-end-of-non-void" warning. */
} else {
/* Parent */
return 0;
}
#endif
}
/** End the current thread/process.
*/
void
spawn_exit(void)
{
#if defined(USE_WIN32_THREADS)
_endthread();
//we should never get here. my compiler thinks that _endthread returns, this
//is an attempt to fool it.
tor_assert(0);
_exit(0);
#elif defined(USE_PTHREADS)
pthread_exit(NULL);
#else
/* http://www.erlenstar.demon.co.uk/unix/faq_2.html says we should
* call _exit, not exit, from child processes. */
_exit(0);
#endif
}
/** Implementation logic for compute_num_cpus(). */
static int
compute_num_cpus_impl(void)
......@@ -2935,280 +2832,6 @@ tor_gmtime_r(const time_t *timep, struct tm *result)
}
#endif
#if defined(USE_WIN32_THREADS)
void
tor_mutex_init(tor_mutex_t *m)
{
InitializeCriticalSection(&m->mutex);
}
void
tor_mutex_uninit(tor_mutex_t *m)
{
DeleteCriticalSection(&m->mutex);
}
void
tor_mutex_acquire(tor_mutex_t *m)
{
tor_assert(m);
EnterCriticalSection(&m->mutex);
}
void
tor_mutex_release(tor_mutex_t *m)
{
LeaveCriticalSection(&m->mutex);
}
unsigned long
tor_get_thread_id(void)
{
return (unsigned long)GetCurrentThreadId();
}
#elif defined(USE_PTHREADS)
/** A mutex attribute that we're going to use to tell pthreads that we want
* "reentrant" mutexes (i.e., once we can re-lock if we're already holding
* them.) */
static pthread_mutexattr_t attr_reentrant;
/** Initialize <b>mutex</b> so it can be locked. Every mutex must be set
* up with tor_mutex_init() or tor_mutex_new(); not both. */
void
tor_mutex_init(tor_mutex_t *mutex)
{
int err;
if (PREDICT_UNLIKELY(!threads_initialized))
tor_threads_init();
err = pthread_mutex_init(&mutex->mutex, &attr_reentrant);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d creating a mutex.", err);
tor_fragile_assert();
}
}
/** Wait until <b>m</b> is free, then acquire it. */
void
tor_mutex_acquire(tor_mutex_t *m)
{
int err;
tor_assert(m);
err = pthread_mutex_lock(&m->mutex);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d locking a mutex.", err);
tor_fragile_assert();
}
}
/** Release the lock <b>m</b> so another thread can have it. */
void
tor_mutex_release(tor_mutex_t *m)
{
int err;
tor_assert(m);
err = pthread_mutex_unlock(&m->mutex);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d unlocking a mutex.", err);
tor_fragile_assert();
}
}
/** Clean up the mutex <b>m</b> so that it no longer uses any system
* resources. Does not free <b>m</b>. This function must only be called on
* mutexes from tor_mutex_init(). */
void
tor_mutex_uninit(tor_mutex_t *m)
{
int err;
tor_assert(m);
err = pthread_mutex_destroy(&m->mutex);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d destroying a mutex.", err);
tor_fragile_assert();
}
}
/** Return an integer representing this thread. */
unsigned long
tor_get_thread_id(void)
{
union {
pthread_t thr;
unsigned long id;
} r;
r.thr = pthread_self();
return r.id;
}
#endif
/** Return a newly allocated, ready-for-use mutex. */
tor_mutex_t *
tor_mutex_new(void)
{
tor_mutex_t *m = tor_malloc_zero(sizeof(tor_mutex_t));
tor_mutex_init(m);
return m;
}
/** Release all storage and system resources held by <b>m</b>. */
void
tor_mutex_free(tor_mutex_t *m)
{
if (!m)
return;
tor_mutex_uninit(m);
tor_free(m);
}
/* Conditions. */
#ifdef USE_PTHREADS
#if 0
/** Cross-platform condition implementation. */
struct tor_cond_t {
pthread_cond_t cond;
};
/** Return a newly allocated condition, with nobody waiting on it. */
tor_cond_t *
tor_cond_new(void)
{
tor_cond_t *cond = tor_malloc_zero(sizeof(tor_cond_t));
if (pthread_cond_init(&cond->cond, NULL)) {
tor_free(cond);
return NULL;
}
return cond;
}
/** Release all resources held by <b>cond</b>. */
void
tor_cond_free(tor_cond_t *cond)
{
if (!cond)
return;
if (pthread_cond_destroy(&cond->cond)) {
log_warn(LD_GENERAL,"Error freeing condition: %s", strerror(errno));
return;
}
tor_free(cond);
}
/** Wait until one of the tor_cond_signal functions is called on <b>cond</b>.
* All waiters on the condition must wait holding the same <b>mutex</b>.
* Returns 0 on success, negative on failure. */
int
tor_cond_wait(tor_cond_t *cond, tor_mutex_t *mutex)
{
return pthread_cond_wait(&cond->cond, &mutex->mutex) ? -1 : 0;
}
/** Wake up one of the waiters on <b>cond</b>. */
void
tor_cond_signal_one(tor_cond_t *cond)
{
pthread_cond_signal(&cond->cond);
}
/** Wake up all of the waiters on <b>cond</b>. */
void
tor_cond_signal_all(tor_cond_t *cond)
{
pthread_cond_broadcast(&cond->cond);
}
#endif
/** Set up common structures for use by threading. */
void
tor_threads_init(void)
{
if (!threads_initialized) {
pthread_mutexattr_init(&attr_reentrant);
pthread_mutexattr_settype(&attr_reentrant, PTHREAD_MUTEX_RECURSIVE);
tor_assert(0==pthread_attr_init(&attr_detached));
tor_assert(0==pthread_attr_setdetachstate(&attr_detached, 1));
threads_initialized = 1;
set_main_thread();
}
}
#elif defined(USE_WIN32_THREADS)
#if 0
static DWORD cond_event_tls_index;
struct tor_cond_t {
CRITICAL_SECTION mutex;
smartlist_t *events;
};
tor_cond_t *
tor_cond_new(void)
{
tor_cond_t *cond = tor_malloc_zero(sizeof(tor_cond_t));
InitializeCriticalSection(&cond->mutex);
cond->events = smartlist_new();
return cond;
}
void
tor_cond_free(tor_cond_t *cond)
{
if (!cond)
return;
DeleteCriticalSection(&cond->mutex);
/* XXXX notify? */
smartlist_free(cond->events);
tor_free(cond);
}
int
tor_cond_wait(tor_cond_t *cond, tor_mutex_t *mutex)
{
HANDLE event;
int r;
tor_assert(cond);
tor_assert(mutex);
event = TlsGetValue(cond_event_tls_index);
if (!event) {
event = CreateEvent(0, FALSE, FALSE, NULL);
TlsSetValue(cond_event_tls_index, event);
}
EnterCriticalSection(&cond->mutex);
tor_assert(WaitForSingleObject(event, 0) == WAIT_TIMEOUT);
tor_assert(!smartlist_contains(cond->events, event));
smartlist_add(cond->events, event);
LeaveCriticalSection(&cond->mutex);
tor_mutex_release(mutex);
r = WaitForSingleObject(event, INFINITE);
tor_mutex_acquire(mutex);
switch (r) {
case WAIT_OBJECT_0: /* we got the mutex normally. */
break;
case WAIT_ABANDONED: /* holding thread exited. */
case WAIT_TIMEOUT: /* Should never happen. */
tor_assert(0);
break;
case WAIT_FAILED:
log_warn(LD_GENERAL, "Failed to acquire mutex: %d",(int) GetLastError());
}
return 0;
}
void
tor_cond_signal_one(tor_cond_t *cond)
{
HANDLE event;
tor_assert(cond);
EnterCriticalSection(&cond->mutex);
if ((event = smartlist_pop_last(cond->events)))
SetEvent(event);
LeaveCriticalSection(&cond->mutex);
}
void
tor_cond_signal_all(tor_cond_t *cond)
{
tor_assert(cond);
EnterCriticalSection(&cond->mutex);
SMARTLIST_FOREACH(cond->events, HANDLE, event, SetEvent(event));
smartlist_clear(cond->events);
LeaveCriticalSection(&cond->mutex);
}
#endif
void
tor_threads_init(void)
{
#if 0
cond_event_tls_index = TlsAlloc();
#endif
set_main_thread();
}
#endif
#if defined(HAVE_MLOCKALL) && HAVE_DECL_MLOCKALL && defined(RLIMIT_MEMLOCK)
/** Attempt to raise the current and max rlimit to infinity for our process.
* This only needs to be done once and can probably only be done when we have
......@@ -3292,23 +2915,6 @@ tor_mlockall(void)
#endif
}
/** Identity of the "main" thread */
static unsigned long main_thread_id = -1;
/** Start considering the current thread to be the 'main thread'. This has
* no effect on anything besides in_main_thread(). */
void
set_main_thread(void)
{
main_thread_id = tor_get_thread_id();
}
/** Return true iff called from the main thread. */
int
in_main_thread(void)
{
return main_thread_id == tor_get_thread_id();
}
/**
* On Windows, WSAEWOULDBLOCK is not always correct: when you see it,
* you need to ask the socket for its actual errno. Also, you need to
......
......@@ -36,9 +36,6 @@
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#if defined(HAVE_PTHREAD_H) && !defined(_WIN32)
#include <pthread.h>
#endif
#include <stdarg.h>
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
......@@ -642,61 +639,10 @@ char **get_environment(void);
int get_total_system_memory(size_t *mem_out);
int spawn_func(void (*func)(void *), void *data);
void spawn_exit(void) ATTR_NORETURN;
#if defined(_WIN32)
#define USE_WIN32_THREADS
#elif defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_CREATE)
#define USE_PTHREADS
#else
#error "No threading system was found"
#endif
int compute_num_cpus(void);
/* Because we use threads instead of processes on most platforms (Windows,
* Linux, etc), we need locking for them. On platforms with poor thread
* support or broken gethostbyname_r, these functions are no-ops. */
/** A generic lock structure for multithreaded builds. */
typedef struct tor_mutex_t {
#if defined(USE_WIN32_THREADS)
/** Windows-only: on windows, we implement locks with CRITICAL_SECTIONS. */
CRITICAL_SECTION mutex;
#elif defined(USE_PTHREADS)
/** Pthreads-only: with pthreads, we implement locks with
* pthread_mutex_t. */
pthread_mutex_t mutex;
#else
/** No-threads only: Dummy variable so that tor_mutex_t takes up space. */
int _unused;
#endif
} tor_mutex_t;
int tor_mlockall(void);
tor_mutex_t *tor_mutex_new(void);
void tor_mutex_init(tor_mutex_t *m);
void tor_mutex_acquire(tor_mutex_t *m);
void tor_mutex_release(tor_mutex_t *m);
void tor_mutex_free(tor_mutex_t *m);
void tor_mutex_uninit(tor_mutex_t *m);
unsigned long tor_get_thread_id(void);
void tor_threads_init(void);
void set_main_thread(void);
int in_main_thread(void);
#if 0
typedef struct tor_cond_t tor_cond_t;
tor_cond_t *tor_cond_new(void);
void tor_cond_free(tor_cond_t *cond);
int tor_cond_wait(tor_cond_t *cond, tor_mutex_t *mutex);
void tor_cond_signal_one(tor_cond_t *cond);
void tor_cond_signal_all(tor_cond_t *cond);
#endif
/** Macros for MIN/MAX. Never use these when the arguments could have
* side-effects.
* {With GCC extensions we could probably define a safer MIN/MAX. But
......@@ -742,5 +688,8 @@ STATIC int tor_ersatz_socketpair(int family, int type, int protocol,
#endif
#endif
/* This needs some of the declarations above so we include it here. */
#include "compat_threads.h"
#endif
/* Copyright (c) 2003-2004, Roger Dingledine
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2015, The Tor Project, Inc. */
/* See LICENSE for licensing information */
#include "orconfig.h"
#include <pthread.h>
#include "compat.h"
#include "torlog.h"
#include "util.h"
/** Wraps a void (*)(void*) function and its argument so we can
* invoke them in a way pthreads would expect.
*/
typedef struct tor_pthread_data_t {
void (*func)(void *);
void *data;
} tor_pthread_data_t;
/** Given a tor_pthread_data_t <b>_data</b>, call _data-&gt;func(d-&gt;data)
* and free _data. Used to make sure we can call functions the way pthread
* expects. */
static void *
tor_pthread_helper_fn(void *_data)
{
tor_pthread_data_t *data = _data;
void (*func)(void*);
void *arg;
/* mask signals to worker threads to avoid SIGPIPE, etc */
sigset_t sigs;
/* We're in a subthread; don't handle any signals here. */
sigfillset(&sigs);
pthread_sigmask(SIG_SETMASK, &sigs, NULL);
func = data->func;
arg = data->data;
tor_free(_data);
func(arg);
return NULL;
}
/**
* A pthread attribute to make threads start detached.
*/
static pthread_attr_t attr_detached;
/** True iff we've called tor_threads_init() */
static int threads_initialized = 0;
/** Minimalist interface to run a void function in the background. On
* Unix calls fork, on win32 calls beginthread. Returns -1 on failure.
* func should not return, but rather should call spawn_exit.
*
* NOTE: if <b>data</b> is used, it should not be allocated on the stack,
* since in a multithreaded environment, there is no way to be sure that
* the caller's stack will still be around when the called function is
* running.
*/
int
spawn_func(void (*func)(void *), void *data)
{
pthread_t thread;
tor_pthread_data_t *d;
if (PREDICT_UNLIKELY(!threads_initialized))
tor_threads_init();
d = tor_malloc(sizeof(tor_pthread_data_t));
d->data = data;
d->func = func;
if (pthread_create(&thread,&attr_detached,tor_pthread_helper_fn,d))
return -1;
return 0;
}
/** End the current thread/process.
*/
void
spawn_exit(void)
{
pthread_exit(NULL);
}
/** A mutex attribute that we're going to use to tell pthreads that we want
* "reentrant" mutexes (i.e., once we can re-lock if we're already holding
* them.) */
static pthread_mutexattr_t attr_reentrant;
/** Initialize <b>mutex</b> so it can be locked. Every mutex must be set
* up with tor_mutex_init() or tor_mutex_new(); not both. */
void
tor_mutex_init(tor_mutex_t *mutex)
{
int err;
if (PREDICT_UNLIKELY(!threads_initialized))
tor_threads_init();
err = pthread_mutex_init(&mutex->mutex, &attr_reentrant);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d creating a mutex.", err);
tor_fragile_assert();
}
}
/** Wait until <b>m</b> is free, then acquire it. */
void
tor_mutex_acquire(tor_mutex_t *m)
{
int err;
tor_assert(m);
err = pthread_mutex_lock(&m->mutex);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d locking a mutex.", err);
tor_fragile_assert();
}
}
/** Release the lock <b>m</b> so another thread can have it. */
void
tor_mutex_release(tor_mutex_t *m)
{
int err;
tor_assert(m);
err = pthread_mutex_unlock(&m->mutex);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d unlocking a mutex.", err);
tor_fragile_assert();
}
}
/** Clean up the mutex <b>m</b> so that it no longer uses any system
* resources. Does not free <b>m</b>. This function must only be called on
* mutexes from tor_mutex_init(). */
void
tor_mutex_uninit(tor_mutex_t *m)
{
int err;
tor_assert(m);
err = pthread_mutex_destroy(&m->mutex);