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Merged
merged 1 commit into from
Jul 12, 2016
Merged

Enable CF runloop support for linux #101

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34 changes: 23 additions & 11 deletions private/private.h
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Original file line number Diff line number Diff line change
Expand Up @@ -166,31 +166,43 @@ void _dispatch_prohibit_transition_to_multithreaded(bool prohibit);
* SPI for CoreFoundation/Foundation ONLY
*/

#define DISPATCH_COCOA_COMPAT (TARGET_OS_MAC || TARGET_OS_WIN32)
#if TARGET_OS_MAC
#define DISPATCH_COCOA_COMPAT 1
#elif defined(__linux__)
#define DISPATCH_COCOA_COMPAT 1
#else
#define DISPATCH_COCOA_COMPAT 0
#endif

#if DISPATCH_COCOA_COMPAT

#define DISPATCH_CF_SPI_VERSION 20160712

#if TARGET_OS_MAC
typedef mach_port_t dispatch_runloop_handle_t;
#elif defined(__linux__)
typedef int dispatch_runloop_handle_t;
#else
#error "runloop support not implemented on this platform"
#endif

#if TARGET_OS_MAC
__OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0)
DISPATCH_EXPORT DISPATCH_CONST DISPATCH_WARN_RESULT DISPATCH_NOTHROW
mach_port_t
dispatch_runloop_handle_t
_dispatch_get_main_queue_port_4CF(void);
#endif

__OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0)
DISPATCH_EXPORT DISPATCH_NOTHROW
void
_dispatch_main_queue_callback_4CF(mach_msg_header_t *_Null_unspecified msg);
#elif TARGET_OS_WIN32
__OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0)
__OSX_AVAILABLE(10.12) __IOS_AVAILABLE(10.0)
__TVOS_AVAILABLE(10.0) __WATCHOS_AVAILABLE(3.0)
DISPATCH_EXPORT DISPATCH_NOTHROW
HANDLE
dispatch_runloop_handle_t
_dispatch_get_main_queue_handle_4CF(void);

__OSX_AVAILABLE_STARTING(__MAC_10_6,__IPHONE_4_0)
DISPATCH_EXPORT DISPATCH_NOTHROW
void
_dispatch_main_queue_callback_4CF(void);
#endif // TARGET_OS_WIN32
_dispatch_main_queue_callback_4CF(void *_Null_unspecified msg);

__OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0)
DISPATCH_EXPORT DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT
Expand Down
3 changes: 3 additions & 0 deletions src/internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -251,6 +251,9 @@ DISPATCH_EXPORT DISPATCH_NOTHROW void dispatch_atfork_child(void);
#include <sys/mman.h>
#include <netinet/in.h>
#endif
#if defined(__linux__)
#include <sys/eventfd.h>
#endif

#ifdef __BLOCKS__
#include <Block_private.h>
Expand Down
165 changes: 129 additions & 36 deletions src/queue.c
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Original file line number Diff line number Diff line change
Expand Up @@ -74,11 +74,11 @@ static int _dispatch_pthread_sigmask(int how, sigset_t *set, sigset_t *oset);
#endif

#if DISPATCH_COCOA_COMPAT
static dispatch_once_t _dispatch_main_q_port_pred;
static dispatch_once_t _dispatch_main_q_handle_pred;
static void _dispatch_runloop_queue_poke(dispatch_queue_t dq,
pthread_priority_t pp, dispatch_wakeup_flags_t flags);
static void _dispatch_runloop_queue_port_init(void *ctxt);
static void _dispatch_runloop_queue_port_dispose(dispatch_queue_t dq);
static void _dispatch_runloop_queue_handle_init(void *ctxt);
static void _dispatch_runloop_queue_handle_dispose(dispatch_queue_t dq);
#endif

static void _dispatch_root_queues_init_once(void *context);
Expand Down Expand Up @@ -4063,6 +4063,48 @@ _dispatch_queue_wakeup(dispatch_queue_t dq, pthread_priority_t pp,
}

#if DISPATCH_COCOA_COMPAT

DISPATCH_ALWAYS_INLINE
static inline bool
_dispatch_runloop_handle_is_valid(dispatch_runloop_handle_t handle)
{
#if TARGET_OS_MAC
return MACH_PORT_VALID(handle);
#elif defined(__linux__)
return handle >= 0;
#else
#error "runloop support not implemented on this platform"
#endif
}

DISPATCH_ALWAYS_INLINE
static inline dispatch_runloop_handle_t
_dispatch_runloop_queue_get_handle(dispatch_queue_t dq)
{
#if TARGET_OS_MAC
return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt);
#elif defined(__linux__)
// decode: 0 is a valid fd, so offset by 1 to distinguish from NULL
return ((dispatch_runloop_handle_t)(uintptr_t)dq->do_ctxt) - 1;
#else
#error "runloop support not implemented on this platform"
#endif
}

DISPATCH_ALWAYS_INLINE
static inline void
_dispatch_runloop_queue_set_handle(dispatch_queue_t dq, dispatch_runloop_handle_t handle)
{
#if TARGET_OS_MAC
dq->do_ctxt = (void *)(uintptr_t)handle;
#elif defined(__linux__)
// encode: 0 is a valid fd, so offset by 1 to distinguish from NULL
dq->do_ctxt = (void *)(uintptr_t)(handle + 1);
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a one-line comment about why this is here would probably be helpful

#else
#error "runloop support not implemented on this platform"
#endif
}

void
_dispatch_runloop_queue_wakeup(dispatch_queue_t dq, pthread_priority_t pp,
dispatch_wakeup_flags_t flags)
Expand Down Expand Up @@ -4090,13 +4132,6 @@ _dispatch_runloop_queue_wakeup(dispatch_queue_t dq, pthread_priority_t pp,
return _dispatch_release_tailcall(dq);
}
}
#else
void
_dispatch_runloop_queue_wakeup(dispatch_queue_t dq, pthread_priority_t pp,
dispatch_wakeup_flags_t flags)
{
LINUX_PORT_ERROR();
}
#endif

void
Expand Down Expand Up @@ -4130,10 +4165,13 @@ _dispatch_root_queue_wakeup(dispatch_queue_t dq,
static inline void
_dispatch_runloop_queue_class_poke(dispatch_queue_t dq)
{
mach_port_t mp = (mach_port_t)dq->do_ctxt;
if (!mp) {
dispatch_runloop_handle_t handle = _dispatch_runloop_queue_get_handle(dq);
if (!_dispatch_runloop_handle_is_valid(handle)) {
return;
}

#if TARGET_OS_MAC
mach_port_t mp = handle;
kern_return_t kr = _dispatch_send_wakeup_runloop_thread(mp, 0);
switch (kr) {
case MACH_SEND_TIMEOUT:
Expand All @@ -4144,6 +4182,15 @@ _dispatch_runloop_queue_class_poke(dispatch_queue_t dq)
(void)dispatch_assume_zero(kr);
break;
}
#elif defined(__linux__)
int result;
do {
result = eventfd_write(handle, 1);
} while (result == -1 && errno == EINTR);
(void)dispatch_assume_zero(result);
#else
#error "runloop support not implemented on this platform"
#endif
}

DISPATCH_NOINLINE
Expand All @@ -4158,8 +4205,8 @@ _dispatch_runloop_queue_poke(dispatch_queue_t dq,
// or in _dispatch_queue_cleanup2() for the main thread.

if (dq == &_dispatch_main_q) {
dispatch_once_f(&_dispatch_main_q_port_pred, dq,
_dispatch_runloop_queue_port_init);
dispatch_once_f(&_dispatch_main_q_handle_pred, dq,
_dispatch_runloop_queue_handle_init);
}
_dispatch_queue_override_priority(dq, /* inout */ &pp, /* inout */ &flags);
if (flags & DISPATCH_WAKEUP_OVERRIDING) {
Expand Down Expand Up @@ -4501,8 +4548,8 @@ _dispatch_main_queue_drain(void)
" from the wrong thread");
}

dispatch_once_f(&_dispatch_main_q_port_pred, dq,
_dispatch_runloop_queue_port_init);
dispatch_once_f(&_dispatch_main_q_handle_pred, dq,
_dispatch_runloop_queue_handle_init);

_dispatch_perfmon_start();
// <rdar://problem/23256682> hide the frame chaining when CFRunLoop
Expand Down Expand Up @@ -5547,7 +5594,7 @@ _dispatch_runloop_root_queue_create_4CF(const char *label, unsigned long flags)
_dispatch_queue_init(dq, DQF_THREAD_BOUND | DQF_CANNOT_TRYSYNC, 1, false);
dq->do_targetq = _dispatch_get_root_queue(_DISPATCH_QOS_CLASS_DEFAULT,true);
dq->dq_label = label ? label : "runloop-queue"; // no-copy contract
_dispatch_runloop_queue_port_init(dq);
_dispatch_runloop_queue_handle_init(dq);
_dispatch_queue_set_bound_thread(dq);
_dispatch_object_debug(dq, "%s", __func__);
return _dispatch_introspection_queue_create(dq);
Expand All @@ -5569,7 +5616,7 @@ _dispatch_runloop_queue_dispose(dispatch_queue_t dq)
{
_dispatch_object_debug(dq, "%s", __func__);
_dispatch_introspection_queue_dispose(dq);
_dispatch_runloop_queue_port_dispose(dq);
_dispatch_runloop_queue_handle_dispose(dq);
_dispatch_queue_destroy(dq);
}

Expand All @@ -5594,23 +5641,26 @@ _dispatch_runloop_root_queue_wakeup_4CF(dispatch_queue_t dq)
_dispatch_runloop_queue_wakeup(dq, 0, false);
}

mach_port_t
dispatch_runloop_handle_t
_dispatch_runloop_root_queue_get_port_4CF(dispatch_queue_t dq)
{
if (slowpath(dq->do_vtable != DISPATCH_VTABLE(queue_runloop))) {
DISPATCH_CLIENT_CRASH(dq->do_vtable, "Not a runloop queue");
}
return (mach_port_t)dq->do_ctxt;
return _dispatch_runloop_queue_get_handle(dq);
}

static void
_dispatch_runloop_queue_port_init(void *ctxt)
_dispatch_runloop_queue_handle_init(void *ctxt)
{
dispatch_queue_t dq = (dispatch_queue_t)ctxt;
mach_port_t mp;
kern_return_t kr;
dispatch_runloop_handle_t handle;

_dispatch_fork_becomes_unsafe();

#if TARGET_OS_MAC
mach_port_t mp;
kern_return_t kr;
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keeping the mach_port_t mp local in this #if and only setting the generic handle var at the end of the block would read more cleanly to me (there is a lot of other code dealing with mp & mach_port_t in this project that this now clashes with style-wise)

kr = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &mp);
DISPATCH_VERIFY_MIG(kr);
(void)dispatch_assume_zero(kr);
Expand All @@ -5628,38 +5678,81 @@ _dispatch_runloop_queue_port_init(void *ctxt)
DISPATCH_VERIFY_MIG(kr);
(void)dispatch_assume_zero(kr);
}
dq->do_ctxt = (void*)(uintptr_t)mp;
handle = mp;
#elif defined(__linux__)
int fd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
if (fd == -1) {
int err = errno;
switch (err) {
case EMFILE:
DISPATCH_CLIENT_CRASH(err, "eventfd() failure: "
"process is out of file descriptors");
break;
case ENFILE:
DISPATCH_CLIENT_CRASH(err, "eventfd() failure: "
"system is out of file descriptors");
break;
case ENOMEM:
DISPATCH_CLIENT_CRASH(err, "eventfd() failure: "
"kernel is out of memory");
break;
default:
DISPATCH_INTERNAL_CRASH(err, "eventfd() failure");
break;
}
}
handle = fd;
#else
#error "runloop support not implemented on this platform"
#endif
_dispatch_runloop_queue_set_handle(dq, handle);
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do you really want to set the handle if it is invalid ? if seems like this wants to be inside an if for the assume above ?

alternatively add a hard failure (CRASH macro) here, similarly to what we have in _dispatch_kq_init() when we cannot create the kq file descriptor (e.g. due the process or system being out of fd's)


_dispatch_program_is_probably_callback_driven = true;
}

static void
_dispatch_runloop_queue_port_dispose(dispatch_queue_t dq)
_dispatch_runloop_queue_handle_dispose(dispatch_queue_t dq)
{
mach_port_t mp = (mach_port_t)dq->do_ctxt;
if (!mp) {
dispatch_runloop_handle_t handle = _dispatch_runloop_queue_get_handle(dq);
if (!_dispatch_runloop_handle_is_valid(handle)) {
return;
}
dq->do_ctxt = NULL;
#if TARGET_OS_MAC
mach_port_t mp = handle;
kern_return_t kr = mach_port_deallocate(mach_task_self(), mp);
DISPATCH_VERIFY_MIG(kr);
(void)dispatch_assume_zero(kr);
kr = mach_port_mod_refs(mach_task_self(), mp, MACH_PORT_RIGHT_RECEIVE, -1);
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this still uses mp and will not compile as is. As above, I think this should keep a mach_port_t mp local inside this #if for symmetry with other such code (and to avoid mistakes like this)

DISPATCH_VERIFY_MIG(kr);
(void)dispatch_assume_zero(kr);
#elif defined(__linux__)
int rc = close(handle);
(void)dispatch_assume_zero(rc);
#else
#error "runloop support not implemented on this platform"
#endif
}

#pragma mark -
#pragma mark dispatch_main_queue

mach_port_t
_dispatch_get_main_queue_port_4CF(void)
dispatch_runloop_handle_t
_dispatch_get_main_queue_handle_4CF(void)
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as in the header comment above, IMO this could be the primary version and _dispatch_get_main_queue_port_4CF just a legacy alias

{
dispatch_queue_t dq = &_dispatch_main_q;
dispatch_once_f(&_dispatch_main_q_port_pred, dq,
_dispatch_runloop_queue_port_init);
return (mach_port_t)dq->do_ctxt;
dispatch_once_f(&_dispatch_main_q_handle_pred, dq,
_dispatch_runloop_queue_handle_init);
return _dispatch_runloop_queue_get_handle(dq);
}

#if TARGET_OS_MAC
dispatch_runloop_handle_t
_dispatch_get_main_queue_port_4CF(void)
{
return _dispatch_get_main_queue_handle_4CF();
}
#endif

static bool main_q_is_draining;

Expand All @@ -5673,7 +5766,7 @@ _dispatch_queue_set_mainq_drain_state(bool arg)
}

void
_dispatch_main_queue_callback_4CF(mach_msg_header_t *msg DISPATCH_UNUSED)
_dispatch_main_queue_callback_4CF(void *ignored DISPATCH_UNUSED)
{
if (main_q_is_draining) {
return;
Expand Down Expand Up @@ -5798,9 +5891,9 @@ _dispatch_queue_cleanup2(void)
#endif

#if DISPATCH_COCOA_COMPAT
dispatch_once_f(&_dispatch_main_q_port_pred, dq,
_dispatch_runloop_queue_port_init);
_dispatch_runloop_queue_port_dispose(dq);
dispatch_once_f(&_dispatch_main_q_handle_pred, dq,
_dispatch_runloop_queue_handle_init);
_dispatch_runloop_queue_handle_dispose(dq);
#endif
}

Expand Down
6 changes: 0 additions & 6 deletions src/shims/linux_stubs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,12 +33,6 @@
#undef LINUX_PORT_ERROR
#define LINUX_PORT_ERROR() do { printf("LINUX_PORT_ERROR_CALLED %s:%d: %s\n",__FILE__,__LINE__,__FUNCTION__); abort(); } while (0)

unsigned long _dispatch_runloop_queue_probe(dispatch_queue_t dq) {
LINUX_PORT_ERROR();
}
void _dispatch_runloop_queue_xref_dispose() { LINUX_PORT_ERROR(); }

void _dispatch_runloop_queue_dispose() { LINUX_PORT_ERROR(); }

/*
* Stubbed out static data
Expand Down