blob: 4fb91bef62f9fa2fa358e04ecfbc5f6187281b3b [file] [log] [blame]
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
/* CFMachPort.c
Copyright (c) 1998 - 2015 Apple Inc. and the Swift project authors
Responsibility: Christopher Kane
*/
#include <CoreFoundation/CFMachPort.h>
#include <CoreFoundation/CFRunLoop.h>
#include <CoreFoundation/CFArray.h>
#if __HAS_DISPATCH__
#include <dispatch/dispatch.h>
#include <dispatch/private.h>
#endif
#include <mach/mach.h>
#include <dlfcn.h>
#include <stdio.h>
#include "CFInternal.h"
#if __HAS_DISPATCH__
static dispatch_queue_t _CFMachPortQueue() {
static volatile dispatch_queue_t __CFMachPortQueue = NULL;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
dispatch_queue_attr_t dqattr = dispatch_queue_attr_make_with_qos_class(DISPATCH_QUEUE_SERIAL, QOS_CLASS_BACKGROUND, 0);
__CFMachPortQueue = dispatch_queue_create("com.apple.CFMachPort", dqattr);
});
return __CFMachPortQueue;
}
#endif
enum {
kCFMachPortStateReady = 0,
kCFMachPortStateInvalidating = 1,
kCFMachPortStateInvalid = 2,
kCFMachPortStateDeallocating = 3
};
struct __CFMachPort {
CFRuntimeBase _base;
int32_t _state;
mach_port_t _port; /* immutable */
#if __HAS_DISPATCH__
dispatch_source_t _dsrc; /* protected by _lock */
dispatch_semaphore_t _dsrc_sem; /* protected by _lock */
#endif
CFMachPortInvalidationCallBack _icallout; /* protected by _lock */
CFRunLoopSourceRef _source; /* immutable, once created */
CFMachPortCallBack _callout; /* immutable */
CFMachPortContext _context; /* immutable */
CFLock_t _lock;
const void *(*retain)(const void *info); // use these to store the real callbacks
void (*release)(const void *info);
};
/* Bit 1 in the base reserved bits is used for has-receive-ref state */
/* Bit 2 in the base reserved bits is used for has-send-ref state */
/* Bit 3 in the base reserved bits is used for has-send-ref2 state */
CF_INLINE Boolean __CFMachPortHasReceive(CFMachPortRef mp) {
return (Boolean)__CFBitfieldGetValue(((const CFRuntimeBase *)mp)->_cfinfo[CF_INFO_BITS], 1, 1);
}
CF_INLINE void __CFMachPortSetHasReceive(CFMachPortRef mp) {
__CFBitfieldSetValue(((CFRuntimeBase *)mp)->_cfinfo[CF_INFO_BITS], 1, 1, 1);
}
CF_INLINE Boolean __CFMachPortHasSend(CFMachPortRef mp) {
return (Boolean)__CFBitfieldGetValue(((const CFRuntimeBase *)mp)->_cfinfo[CF_INFO_BITS], 2, 2);
}
CF_INLINE void __CFMachPortSetHasSend(CFMachPortRef mp) {
__CFBitfieldSetValue(((CFRuntimeBase *)mp)->_cfinfo[CF_INFO_BITS], 2, 2, 1);
}
CF_INLINE Boolean __CFMachPortHasSend2(CFMachPortRef mp) {
return (Boolean)__CFBitfieldGetValue(((const CFRuntimeBase *)mp)->_cfinfo[CF_INFO_BITS], 3, 3);
}
/*
//TODO we should either use this or delete the entire Send2 flag concept
CF_INLINE void __CFMachPortSetHasSend2(CFMachPortRef mp) {
__CFBitfieldSetValue(((CFRuntimeBase *)mp)->_cfinfo[CF_INFO_BITS], 3, 3, 1);
}
*/
CF_INLINE Boolean __CFMachPortIsValid(CFMachPortRef mp) {
return kCFMachPortStateReady == mp->_state;
}
void _CFMachPortInstallNotifyPort(CFRunLoopRef rl, CFStringRef mode) {
}
static Boolean __CFMachPortEqual(CFTypeRef cf1, CFTypeRef cf2) {
CFMachPortRef mp1 = (CFMachPortRef)cf1;
CFMachPortRef mp2 = (CFMachPortRef)cf2;
return (mp1->_port == mp2->_port);
}
static CFHashCode __CFMachPortHash(CFTypeRef cf) {
CFMachPortRef mp = (CFMachPortRef)cf;
return (CFHashCode)mp->_port;
}
static CFStringRef __CFMachPortCopyDescription(CFTypeRef cf) {
CFMachPortRef mp = (CFMachPortRef)cf;
CFStringRef contextDesc = NULL;
if (NULL != mp->_context.info && NULL != mp->_context.copyDescription) {
contextDesc = mp->_context.copyDescription(mp->_context.info);
}
if (NULL == contextDesc) {
contextDesc = CFStringCreateWithFormat(kCFAllocatorSystemDefault, NULL, CFSTR("<CFMachPort context %p>"), mp->_context.info);
}
Dl_info info;
void *addr = mp->_callout;
const char *name = (dladdr(addr, &info) && info.dli_saddr == addr && info.dli_sname) ? info.dli_sname : "???";
CFStringRef result = CFStringCreateWithFormat(kCFAllocatorSystemDefault, NULL, CFSTR("<CFMachPort %p [%p]>{valid = %s, port = %x, source = %p, callout = %s (%p), context = %@}"), cf, CFGetAllocator(mp), (__CFMachPortIsValid(mp) ? "Yes" : "No"), mp->_port, mp->_source, name, addr, contextDesc);
if (NULL != contextDesc) {
CFRelease(contextDesc);
}
return result;
}
// Only call with mp->_lock locked
CF_INLINE void __CFMachPortInvalidateLocked(CFRunLoopSourceRef source, CFMachPortRef mp) {
CFMachPortInvalidationCallBack cb = mp->_icallout;
if (cb) {
__CFUnlock(&mp->_lock);
cb(mp, mp->_context.info);
__CFLock(&mp->_lock);
}
if (NULL != source) {
__CFUnlock(&mp->_lock);
CFRunLoopSourceInvalidate(source);
CFRelease(source);
__CFLock(&mp->_lock);
}
void *info = mp->_context.info;
void (*release)(const void *info) = mp->release;
mp->_context.info = NULL;
if (release) {
__CFUnlock(&mp->_lock);
release(info);
__CFLock(&mp->_lock);
}
mp->_state = kCFMachPortStateInvalid;
OSMemoryBarrier();
}
static void __CFMachPortDeallocate(CFTypeRef cf) {
CHECK_FOR_FORK_RET();
CFMachPortRef mp = (CFMachPortRef)cf;
// CFMachPortRef is invalid before we get here, except under GC
__CFLock(&mp->_lock);
CFRunLoopSourceRef source = NULL;
Boolean wasReady = (mp->_state == kCFMachPortStateReady);
if (wasReady) {
mp->_state = kCFMachPortStateInvalidating;
OSMemoryBarrier();
#if __HAS_DISPATCH__
if (mp->_dsrc) {
dispatch_source_cancel(mp->_dsrc);
mp->_dsrc = NULL;
}
#endif
source = mp->_source;
mp->_source = NULL;
}
if (wasReady) {
__CFMachPortInvalidateLocked(source, mp);
}
mp->_state = kCFMachPortStateDeallocating;
// hand ownership of the port and semaphores to the block below
mach_port_t port = mp->_port;
#if __HAS_DISPATCH__
dispatch_semaphore_t sem1 = mp->_dsrc_sem;
#endif
Boolean doSend2 = __CFMachPortHasSend2(mp), doSend = __CFMachPortHasSend(mp), doReceive = __CFMachPortHasReceive(mp);
__CFUnlock(&mp->_lock);
#if __HAS_DISPATCH__
dispatch_async(__CFDispatchQueueGetGenericBackground(), ^{
if (sem1) {
dispatch_semaphore_wait(sem1, DISPATCH_TIME_FOREVER);
// immediate release is only safe if dispatch_semaphore_signal() does not touch the semaphore after doing the signal bit
dispatch_release(sem1);
}
// MUST deallocate the send right FIRST if necessary,
// then the receive right if necessary. Don't ask me why;
// if it's done in the other order the port will leak.
if (doSend2) {
mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_SEND, -1);
}
if (doSend) {
mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_SEND, -1);
}
if (doReceive) {
mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
}
});
#endif
}
// This lock protects __CFAllMachPorts. Take before any instance-specific lock.
static CFLock_t __CFAllMachPortsLock = CFLockInit;
static CFMutableArrayRef __CFAllMachPorts = NULL;
static Boolean __CFMachPortCheck(mach_port_t) __attribute__((noinline));
static Boolean __CFMachPortCheck(mach_port_t port) {
mach_port_type_t type = 0;
kern_return_t ret = mach_port_type(mach_task_self(), port, &type);
return (KERN_SUCCESS != ret || (0 == (type & MACH_PORT_TYPE_PORT_RIGHTS))) ? false : true;
}
#if 0
static void __CFMachPortChecker(Boolean fromTimer) {
__CFLock(&__CFAllMachPortsLock); // take this lock first before any instance-specific lock
for (CFIndex idx = 0, cnt = __CFAllMachPorts ? CFArrayGetCount(__CFAllMachPorts) : 0; idx < cnt; idx++) {
CFMachPortRef mp = (CFMachPortRef)CFArrayGetValueAtIndex(__CFAllMachPorts, idx);
if (!mp) continue;
// second clause cleans no-longer-wanted CFMachPorts out of our strong table
if (!__CFMachPortCheck(mp->_port) || (!kCFUseCollectableAllocator && 1 == CFGetRetainCount(mp))) {
CFRunLoopSourceRef source = NULL;
Boolean wasReady = (mp->_state == kCFMachPortStateReady);
if (wasReady) {
__CFLock(&mp->_lock); // take this lock second
// double check the state under lock, just in case, we should be the last reference per retain count check above... but it doesn't hurt to be robust.
wasReady = (mp->_state == kCFMachPortStateReady);
if (!wasReady) {
__CFUnlock(&mp->_lock);
}
else {
mp->_state = kCFMachPortStateInvalidating;
OSMemoryBarrier();
#if __HAS_DISPATCH__
if (mp->_dsrc) {
dispatch_source_cancel(mp->_dsrc);
mp->_dsrc = NULL;
}
#endif
source = mp->_source;
mp->_source = NULL;
CFRetain(mp);
__CFUnlock(&mp->_lock);
#if __HAS_DISPATCH__
dispatch_async(dispatch_get_main_queue(), ^{
// We can grab the mach port-specific spin lock here since we're no longer on the same thread as the one taking the all mach ports spin lock.
// But be sure to release it during callouts
__CFLock(&mp->_lock);
__CFMachPortInvalidateLocked(source, mp);
__CFUnlock(&mp->_lock);
CFRelease(mp);
});
#endif
}
}
CFArrayRemoveValueAtIndex(__CFAllMachPorts, idx);
idx--;
cnt--;
}
}
__CFUnlock(&__CFAllMachPortsLock);
};
#endif
static CFTypeID __kCFMachPortTypeID = _kCFRuntimeNotATypeID;
static const CFRuntimeClass __CFMachPortClass = {
0,
"CFMachPort",
NULL, // init
NULL, // copy
__CFMachPortDeallocate,
__CFMachPortEqual,
__CFMachPortHash,
NULL, //
__CFMachPortCopyDescription
};
CFTypeID CFMachPortGetTypeID(void) {
static dispatch_once_t initOnce = 0;
dispatch_once(&initOnce, ^{ __kCFMachPortTypeID = _CFRuntimeRegisterClass(&__CFMachPortClass); });
return __kCFMachPortTypeID;
}
/* Note: any receive or send rights that the port contains coming in will
* not be cleaned up by CFMachPort; it will increment and decrement
* references on the port if the kernel ever allows that in the future,
* but will not cleanup any references you got when you got the port. */
CFMachPortRef _CFMachPortCreateWithPort2(CFAllocatorRef allocator, mach_port_t port, CFMachPortCallBack callout, CFMachPortContext *context, Boolean *shouldFreeInfo, Boolean deathWatch) {
if (shouldFreeInfo) *shouldFreeInfo = true;
CHECK_FOR_FORK_RET(NULL);
mach_port_type_t type = 0;
kern_return_t ret = mach_port_type(mach_task_self(), port, &type);
if (KERN_SUCCESS != ret || (0 == (type & MACH_PORT_TYPE_PORT_RIGHTS))) {
if (type & ~MACH_PORT_TYPE_DEAD_NAME) {
CFLog(kCFLogLevelError, CFSTR("*** CFMachPortCreateWithPort(): bad Mach port parameter (0x%lx) or unsupported mysterious kind of Mach port (%d, %ld)"), (unsigned long)port, ret, (unsigned long)type);
}
return NULL;
}
#if 0
static dispatch_source_t timerSource = NULL;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
timerSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_INTERVAL, 60 * 1000 /* milliseconds */, 0, _CFMachPortQueue());
dispatch_source_set_event_handler(timerSource, ^{
__CFMachPortChecker(true);
});
dispatch_resume(timerSource);
});
#endif
CFMachPortRef mp = NULL;
__CFLock(&__CFAllMachPortsLock);
for (CFIndex idx = 0, cnt = __CFAllMachPorts ? CFArrayGetCount(__CFAllMachPorts) : 0; idx < cnt; idx++) {
CFMachPortRef p = (CFMachPortRef)CFArrayGetValueAtIndex(__CFAllMachPorts, idx);
if (p && p->_port == port) {
CFRetain(p);
mp = p;
break;
}
}
__CFUnlock(&__CFAllMachPortsLock);
if (!mp) {
CFIndex size = sizeof(struct __CFMachPort) - sizeof(CFRuntimeBase);
CFMachPortRef memory = (CFMachPortRef)_CFRuntimeCreateInstance(allocator, CFMachPortGetTypeID(), size, NULL);
if (NULL == memory) {
return NULL;
}
memory->_port = port;
#if __HAS_DISPATCH__
memory->_dsrc = NULL;
memory->_dsrc_sem = NULL;
#endif
memory->_icallout = NULL;
memory->_source = NULL;
memory->_context.info = NULL;
memory->_context.retain = NULL;
memory->_context.release = NULL;
memory->_context.copyDescription = NULL;
memory->retain = NULL;
memory->release = NULL;
memory->_callout = callout;
memory->_lock = CFLockInit;
if (NULL != context) {
objc_memmove_collectable(&memory->_context, context, sizeof(CFMachPortContext));
memory->_context.info = context->retain ? (void *)context->retain(context->info) : context->info;
memory->retain = context->retain;
memory->release = context->release;
memory->_context.retain = (void *)0xAAAAAAAAAACCCAAA;
memory->_context.release = (void *)0xAAAAAAAAAABBBAAA;
}
memory->_state = kCFMachPortStateReady;
__CFLock(&__CFAllMachPortsLock);
if (!__CFAllMachPorts) __CFAllMachPorts = CFArrayCreateMutable(kCFAllocatorSystemDefault, 0, &kCFTypeArrayCallBacks);
CFArrayAppendValue(__CFAllMachPorts, memory);
__CFUnlock(&__CFAllMachPortsLock);
mp = memory;
if (shouldFreeInfo) *shouldFreeInfo = false;
#if __HAS_DISPATCH__
if (type & MACH_PORT_TYPE_SEND_RIGHTS) {
dispatch_source_t theSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_MACH_SEND, port, DISPATCH_MACH_SEND_DEAD, _CFMachPortQueue());
if (theSource) {
dispatch_semaphore_t sem = dispatch_semaphore_create(0);
dispatch_retain(sem);
dispatch_source_set_cancel_handler(theSource, ^{ dispatch_semaphore_signal(sem); dispatch_release(sem); dispatch_release(theSource); });
dispatch_source_set_event_handler(theSource, ^{ __CFMachPortChecker(false); });
memory->_dsrc_sem = sem;
memory->_dsrc = theSource;
dispatch_resume(theSource);
}
}
#endif
}
if (mp && !CFMachPortIsValid(mp)) { // must do this outside lock to avoid deadlock
CFRelease(mp);
mp = NULL;
}
return mp;
}
CFMachPortRef CFMachPortCreateWithPort(CFAllocatorRef allocator, mach_port_t port, CFMachPortCallBack callout, CFMachPortContext *context, Boolean *shouldFreeInfo) {
return _CFMachPortCreateWithPort2(allocator, port, callout, context, shouldFreeInfo, true);
}
CFMachPortRef CFMachPortCreate(CFAllocatorRef allocator, CFMachPortCallBack callout, CFMachPortContext *context, Boolean *shouldFreeInfo) {
if (shouldFreeInfo) *shouldFreeInfo = true;
CHECK_FOR_FORK_RET(NULL);
mach_port_t port = MACH_PORT_NULL;
kern_return_t ret = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port);
if (KERN_SUCCESS == ret) {
ret = mach_port_insert_right(mach_task_self(), port, port, MACH_MSG_TYPE_MAKE_SEND);
}
if (KERN_SUCCESS != ret) {
if (MACH_PORT_NULL != port) mach_port_destroy(mach_task_self(), port);
return NULL;
}
CFMachPortRef result = _CFMachPortCreateWithPort2(allocator, port, callout, context, shouldFreeInfo, true);
if (NULL == result) {
if (MACH_PORT_NULL != port) mach_port_destroy(mach_task_self(), port);
return NULL;
}
__CFMachPortSetHasReceive(result);
__CFMachPortSetHasSend(result);
return result;
}
void CFMachPortInvalidate(CFMachPortRef mp) {
CHECK_FOR_FORK_RET();
CF_OBJC_FUNCDISPATCHV(CFMachPortGetTypeID(), void, (NSMachPort *)mp, invalidate);
__CFGenericValidateType(mp, CFMachPortGetTypeID());
CFRetain(mp);
CFRunLoopSourceRef source = NULL;
Boolean wasReady = false;
__CFLock(&__CFAllMachPortsLock); // take this lock first
__CFLock(&mp->_lock);
wasReady = (mp->_state == kCFMachPortStateReady);
if (wasReady) {
mp->_state = kCFMachPortStateInvalidating;
OSMemoryBarrier();
for (CFIndex idx = 0, cnt = __CFAllMachPorts ? CFArrayGetCount(__CFAllMachPorts) : 0; idx < cnt; idx++) {
CFMachPortRef p = (CFMachPortRef)CFArrayGetValueAtIndex(__CFAllMachPorts, idx);
if (p == mp) {
CFArrayRemoveValueAtIndex(__CFAllMachPorts, idx);
break;
}
}
#if __HAS_DISPATCH__
if (mp->_dsrc) {
dispatch_source_cancel(mp->_dsrc);
mp->_dsrc = NULL;
}
#endif
source = mp->_source;
mp->_source = NULL;
}
__CFUnlock(&mp->_lock);
__CFUnlock(&__CFAllMachPortsLock); // release this lock last
if (wasReady) {
__CFLock(&mp->_lock);
__CFMachPortInvalidateLocked(source, mp);
__CFUnlock(&mp->_lock);
}
CFRelease(mp);
}
mach_port_t CFMachPortGetPort(CFMachPortRef mp) {
CHECK_FOR_FORK_RET(0);
CF_OBJC_FUNCDISPATCHV(CFMachPortGetTypeID(), mach_port_t, (NSMachPort *)mp, machPort);
__CFGenericValidateType(mp, CFMachPortGetTypeID());
return mp->_port;
}
void CFMachPortGetContext(CFMachPortRef mp, CFMachPortContext *context) {
__CFGenericValidateType(mp, CFMachPortGetTypeID());
CFAssert(0 == context->version, __kCFLogAssertion, "%s(): context version not initialized to 0", __PRETTY_FUNCTION__);
objc_memmove_collectable(context, &mp->_context, sizeof(CFMachPortContext));
}
Boolean CFMachPortIsValid(CFMachPortRef mp) {
CF_OBJC_FUNCDISPATCHV(CFMachPortGetTypeID(), Boolean, (NSMachPort *)mp, isValid);
__CFGenericValidateType(mp, CFMachPortGetTypeID());
if (!__CFMachPortIsValid(mp)) return false;
mach_port_type_t type = 0;
kern_return_t ret = mach_port_type(mach_task_self(), mp->_port, &type);
if (KERN_SUCCESS != ret || (type & ~(MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_SEND_ONCE|MACH_PORT_TYPE_RECEIVE|MACH_PORT_TYPE_DNREQUEST))) {
return false;
}
return true;
}
CFMachPortInvalidationCallBack CFMachPortGetInvalidationCallBack(CFMachPortRef mp) {
__CFGenericValidateType(mp, CFMachPortGetTypeID());
__CFLock(&mp->_lock);
CFMachPortInvalidationCallBack cb = mp->_icallout;
__CFUnlock(&mp->_lock);
return cb;
}
/* After the CFMachPort has started going invalid, or done invalid, you can't change this, and
we'll only do the callout directly on a transition from NULL to non-NULL. */
void CFMachPortSetInvalidationCallBack(CFMachPortRef mp, CFMachPortInvalidationCallBack callout) {
CHECK_FOR_FORK_RET();
__CFGenericValidateType(mp, CFMachPortGetTypeID());
if (callout) {
mach_port_type_t type = 0;
kern_return_t ret = mach_port_type(mach_task_self(), mp->_port, &type);
if (KERN_SUCCESS != ret || 0 == (type & MACH_PORT_TYPE_SEND_RIGHTS)) {
CFLog(kCFLogLevelError, CFSTR("*** WARNING: CFMachPortSetInvalidationCallBack() called on a CFMachPort with a Mach port (0x%x) which does not have any send rights. This is not going to work. Callback function: %p"), mp->_port, callout);
}
}
__CFLock(&mp->_lock);
if (__CFMachPortIsValid(mp) || !callout) {
mp->_icallout = callout;
} else if (!mp->_icallout && callout) {
__CFUnlock(&mp->_lock);
callout(mp, mp->_context.info);
__CFLock(&mp->_lock);
} else {
CFLog(kCFLogLevelWarning, CFSTR("CFMachPortSetInvalidationCallBack(): attempt to set invalidation callback (%p) on invalid CFMachPort (%p) thwarted"), callout, mp);
}
__CFUnlock(&mp->_lock);
}
/* Returns the number of messages queued for a receive port. */
CFIndex CFMachPortGetQueuedMessageCount(CFMachPortRef mp) {
CHECK_FOR_FORK_RET(0);
__CFGenericValidateType(mp, CFMachPortGetTypeID());
mach_port_status_t status;
mach_msg_type_number_t num = MACH_PORT_RECEIVE_STATUS_COUNT;
kern_return_t ret = mach_port_get_attributes(mach_task_self(), mp->_port, MACH_PORT_RECEIVE_STATUS, (mach_port_info_t)&status, &num);
return (KERN_SUCCESS != ret) ? 0 : status.mps_msgcount;
}
static mach_port_t __CFMachPortGetPort(void *info) {
CFMachPortRef mp = (CFMachPortRef)info;
return mp->_port;
}
CF_PRIVATE void *__CFMachPortPerform(void *msg, CFIndex size, CFAllocatorRef allocator, void *info) {
CHECK_FOR_FORK_RET(NULL);
CFMachPortRef mp = (CFMachPortRef)info;
__CFLock(&mp->_lock);
Boolean isValid = __CFMachPortIsValid(mp);
void *context_info = NULL;
void (*context_release)(const void *) = NULL;
if (isValid) {
if (mp->retain) {
context_info = (void *)mp->retain(mp->_context.info);
context_release = mp->release;
} else {
context_info = mp->_context.info;
}
}
__CFUnlock(&mp->_lock);
if (isValid) {
mp->_callout(mp, msg, size, context_info);
if (context_release) {
context_release(context_info);
}
CHECK_FOR_FORK_RET(NULL);
}
return NULL;
}
CFRunLoopSourceRef CFMachPortCreateRunLoopSource(CFAllocatorRef allocator, CFMachPortRef mp, CFIndex order) {
CHECK_FOR_FORK_RET(NULL);
__CFGenericValidateType(mp, CFMachPortGetTypeID());
if (!CFMachPortIsValid(mp)) return NULL;
CFRunLoopSourceRef result = NULL;
__CFLock(&mp->_lock);
if (__CFMachPortIsValid(mp)) {
if (NULL != mp->_source && !CFRunLoopSourceIsValid(mp->_source)) {
CFRelease(mp->_source);
mp->_source = NULL;
}
if (NULL == mp->_source) {
CFRunLoopSourceContext1 context;
context.version = 1;
context.info = (void *)mp;
context.retain = (const void *(*)(const void *))CFRetain;
context.release = (void (*)(const void *))CFRelease;
context.copyDescription = (CFStringRef (*)(const void *))__CFMachPortCopyDescription;
context.equal = __CFMachPortEqual;
context.hash = (CFHashCode (*)(const void *))__CFMachPortHash;
context.getPort = __CFMachPortGetPort;
context.perform = __CFMachPortPerform;
mp->_source = CFRunLoopSourceCreate(allocator, order, (CFRunLoopSourceContext *)&context);
}
result = mp->_source ? (CFRunLoopSourceRef)CFRetain(mp->_source) : NULL;
}
__CFUnlock(&mp->_lock);
return result;
}