blob: fbb03736f2a5709a15ea63a5cae796ea967cf158 [file] [log] [blame]
/*
* Copyright (c) 2009-2013 Apple Inc. All rights reserved.
*
* @APPLE_APACHE_LICENSE_HEADER_START@
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @APPLE_APACHE_LICENSE_HEADER_END@
*/
#include "internal.h"
#if defined(__FreeBSD__)
#include <fcntl.h>
#define F_RDADVISE F_RDAHEAD
#endif
#ifndef DISPATCH_IO_DEBUG
#define DISPATCH_IO_DEBUG DISPATCH_DEBUG
#endif
#ifndef PAGE_SIZE
#if defined(_WIN32)
static DWORD
getpagesize(void)
{
SYSTEM_INFO siInfo;
GetSystemInfo(&siInfo);
return siInfo.dwPageSize;
}
#endif
#define PAGE_SIZE ((size_t)getpagesize())
#endif
#if DISPATCH_DATA_IS_BRIDGED_TO_NSDATA
#define _dispatch_io_data_retain(x) _dispatch_objc_retain(x)
#define _dispatch_io_data_release(x) _dispatch_objc_release(x)
#else
#define _dispatch_io_data_retain(x) dispatch_retain(x)
#define _dispatch_io_data_release(x) dispatch_release(x)
#endif
typedef void (^dispatch_fd_entry_init_callback_t)(dispatch_fd_entry_t fd_entry);
DISPATCH_EXPORT DISPATCH_NOTHROW
void _dispatch_iocntl(uint32_t param, uint64_t value);
static dispatch_operation_t _dispatch_operation_create(
dispatch_op_direction_t direction, dispatch_io_t channel, off_t offset,
size_t length, dispatch_data_t data, dispatch_queue_t queue,
dispatch_io_handler_t handler);
static void _dispatch_operation_enqueue(dispatch_operation_t op,
dispatch_op_direction_t direction, dispatch_data_t data);
static dispatch_source_t _dispatch_operation_timer(dispatch_queue_t tq,
dispatch_operation_t op);
static inline void _dispatch_fd_entry_retain(dispatch_fd_entry_t fd_entry);
static inline void _dispatch_fd_entry_release(dispatch_fd_entry_t fd_entry);
static void _dispatch_fd_entry_init_async(dispatch_fd_t fd,
dispatch_fd_entry_init_callback_t completion_callback);
static dispatch_fd_entry_t _dispatch_fd_entry_create_with_fd(dispatch_fd_t fd,
uintptr_t hash);
static dispatch_fd_entry_t _dispatch_fd_entry_create_with_path(
dispatch_io_path_data_t path_data, dev_t dev, mode_t mode);
static int _dispatch_fd_entry_open(dispatch_fd_entry_t fd_entry,
dispatch_io_t channel);
static void _dispatch_fd_entry_cleanup_operations(dispatch_fd_entry_t fd_entry,
dispatch_io_t channel);
static void _dispatch_stream_init(dispatch_fd_entry_t fd_entry,
dispatch_queue_t tq);
static void _dispatch_stream_dispose(dispatch_fd_entry_t fd_entry,
dispatch_op_direction_t direction);
static void _dispatch_disk_init(dispatch_fd_entry_t fd_entry, dev_t dev);
static void _dispatch_stream_enqueue_operation(dispatch_stream_t stream,
dispatch_operation_t operation, dispatch_data_t data);
static void _dispatch_disk_enqueue_operation(dispatch_disk_t dsk,
dispatch_operation_t operation, dispatch_data_t data);
static void _dispatch_stream_cleanup_operations(dispatch_stream_t stream,
dispatch_io_t channel);
static void _dispatch_disk_cleanup_inactive_operations(dispatch_disk_t disk,
dispatch_io_t channel);
static void _dispatch_stream_source_handler(void *ctx);
static void _dispatch_stream_queue_handler(void *ctx);
static void _dispatch_stream_handler(void *ctx);
static void _dispatch_disk_handler(void *ctx);
static void _dispatch_disk_perform(void *ctxt);
static void _dispatch_operation_advise(dispatch_operation_t op,
size_t chunk_size);
static int _dispatch_operation_perform(dispatch_operation_t op);
static void _dispatch_operation_deliver_data(dispatch_operation_t op,
dispatch_op_flags_t flags);
// Macros to wrap syscalls which return -1 on error, and retry on EINTR
#define _dispatch_io_syscall_switch_noerr(_err, _syscall, ...) do { \
switch (((_err) = (((_syscall) == -1) ? errno : 0))) { \
case EINTR: continue; \
__VA_ARGS__ \
} \
break; \
} while (1)
#define _dispatch_io_syscall_switch(__err, __syscall, ...) do { \
_dispatch_io_syscall_switch_noerr(__err, __syscall, \
case 0: break; \
__VA_ARGS__ \
); \
} while (0)
#define _dispatch_io_syscall(__syscall) do { int __err; \
_dispatch_io_syscall_switch(__err, __syscall); \
} while (0)
enum {
DISPATCH_OP_COMPLETE = 1,
DISPATCH_OP_DELIVER,
DISPATCH_OP_DELIVER_AND_COMPLETE,
DISPATCH_OP_COMPLETE_RESUME,
DISPATCH_OP_RESUME,
DISPATCH_OP_ERR,
DISPATCH_OP_FD_ERR,
};
#define _dispatch_io_Block_copy(x) \
((__typeof__(x))_dispatch_Block_copy((dispatch_block_t)(x)))
#pragma mark -
#pragma mark dispatch_io_debug
#if DISPATCH_IO_DEBUG
#if !DISPATCH_DEBUG
#define _dispatch_io_log(x, ...) do { \
_dispatch_log("%llu\t%p\t" x, _dispatch_absolute_time(), \
(void *)_dispatch_thread_self(), ##__VA_ARGS__); \
} while (0)
#ifdef _dispatch_object_debug
#undef _dispatch_object_debug
#define _dispatch_object_debug dispatch_debug
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
#endif
#else
#define _dispatch_io_log(x, ...) _dispatch_debug(x, ##__VA_ARGS__)
#endif // DISPATCH_DEBUG
#else
#define _dispatch_io_log(x, ...)
#endif // DISPATCH_IO_DEBUG
#define _dispatch_fd_debug(msg, fd, ...) \
_dispatch_io_log("fd[0x%x]: " msg, fd, ##__VA_ARGS__)
#define _dispatch_op_debug(msg, op, ...) \
_dispatch_io_log("op[%p]: " msg, op, ##__VA_ARGS__)
#define _dispatch_channel_debug(msg, channel, ...) \
_dispatch_io_log("channel[%p]: " msg, channel, ##__VA_ARGS__)
#define _dispatch_fd_entry_debug(msg, fd_entry, ...) \
_dispatch_io_log("fd_entry[%p]: " msg, fd_entry, ##__VA_ARGS__)
#define _dispatch_disk_debug(msg, disk, ...) \
_dispatch_io_log("disk[%p]: " msg, disk, ##__VA_ARGS__)
#pragma mark -
#pragma mark dispatch_io_hashtables
// Global hashtable of dev_t -> disk_s mappings
DISPATCH_CACHELINE_ALIGN
static TAILQ_HEAD(, dispatch_disk_s) _dispatch_io_devs[DIO_HASH_SIZE];
// Global hashtable of fd -> fd_entry_s mappings
DISPATCH_CACHELINE_ALIGN
static TAILQ_HEAD(, dispatch_fd_entry_s) _dispatch_io_fds[DIO_HASH_SIZE];
static dispatch_once_t _dispatch_io_devs_lockq_pred;
static dispatch_queue_t _dispatch_io_devs_lockq;
static dispatch_queue_t _dispatch_io_fds_lockq;
static char const * const _dispatch_io_key = "io";
static void
_dispatch_io_fds_lockq_init(void *context DISPATCH_UNUSED)
{
_dispatch_io_fds_lockq = dispatch_queue_create(
"com.apple.libdispatch-io.fd_lockq", NULL);
unsigned int i;
for (i = 0; i < DIO_HASH_SIZE; i++) {
TAILQ_INIT(&_dispatch_io_fds[i]);
}
}
static void
_dispatch_io_devs_lockq_init(void *context DISPATCH_UNUSED)
{
_dispatch_io_devs_lockq = dispatch_queue_create(
"com.apple.libdispatch-io.dev_lockq", NULL);
unsigned int i;
for (i = 0; i < DIO_HASH_SIZE; i++) {
TAILQ_INIT(&_dispatch_io_devs[i]);
}
}
#pragma mark -
#pragma mark dispatch_io_defaults
enum {
DISPATCH_IOCNTL_CHUNK_PAGES = 1,
DISPATCH_IOCNTL_LOW_WATER_CHUNKS,
DISPATCH_IOCNTL_INITIAL_DELIVERY,
DISPATCH_IOCNTL_MAX_PENDING_IO_REQS,
};
static struct dispatch_io_defaults_s {
size_t chunk_size, low_water_chunks, max_pending_io_reqs;
bool initial_delivery;
} dispatch_io_defaults = {
.chunk_size = DIO_MAX_CHUNK_SIZE,
.low_water_chunks = DIO_DEFAULT_LOW_WATER_CHUNKS,
.max_pending_io_reqs = DIO_MAX_PENDING_IO_REQS,
};
#define _dispatch_iocntl_set_default(p, v) do { \
dispatch_io_defaults.p = (__typeof__(dispatch_io_defaults.p))(v); \
} while (0)
void
_dispatch_iocntl(uint32_t param, uint64_t value)
{
switch (param) {
case DISPATCH_IOCNTL_CHUNK_PAGES:
_dispatch_iocntl_set_default(chunk_size, value * PAGE_SIZE);
break;
case DISPATCH_IOCNTL_LOW_WATER_CHUNKS:
_dispatch_iocntl_set_default(low_water_chunks, value);
break;
case DISPATCH_IOCNTL_INITIAL_DELIVERY:
_dispatch_iocntl_set_default(initial_delivery, value);
case DISPATCH_IOCNTL_MAX_PENDING_IO_REQS:
_dispatch_iocntl_set_default(max_pending_io_reqs, value);
break;
}
}
#pragma mark -
#pragma mark dispatch_io_t
static dispatch_io_t
_dispatch_io_create(dispatch_io_type_t type)
{
dispatch_io_t channel = _dispatch_object_alloc(DISPATCH_VTABLE(io),
sizeof(struct dispatch_io_s));
channel->do_next = DISPATCH_OBJECT_LISTLESS;
channel->do_targetq = _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, true);
channel->params.type = type;
channel->params.high = SIZE_MAX;
channel->params.low = dispatch_io_defaults.low_water_chunks *
dispatch_io_defaults.chunk_size;
channel->queue = dispatch_queue_create("com.apple.libdispatch-io.channelq",
NULL);
return channel;
}
static void
_dispatch_io_init(dispatch_io_t channel, dispatch_fd_entry_t fd_entry,
dispatch_queue_t queue, int err, void (^cleanup_handler)(int))
{
// Enqueue the cleanup handler on the suspended close queue
if (cleanup_handler) {
_dispatch_retain(queue);
dispatch_async(!err ? fd_entry->close_queue : channel->queue, ^{
dispatch_async(queue, ^{
_dispatch_channel_debug("cleanup handler invoke: err %d",
channel, err);
cleanup_handler(err);
});
_dispatch_release(queue);
});
}
if (fd_entry) {
channel->fd_entry = fd_entry;
dispatch_retain(fd_entry->barrier_queue);
dispatch_retain(fd_entry->barrier_group);
channel->barrier_queue = fd_entry->barrier_queue;
channel->barrier_group = fd_entry->barrier_group;
} else {
// Still need to create a barrier queue, since all operations go
// through it
channel->barrier_queue = dispatch_queue_create(
"com.apple.libdispatch-io.barrierq", NULL);
channel->barrier_group = dispatch_group_create();
}
}
void
_dispatch_io_dispose(dispatch_io_t channel, DISPATCH_UNUSED bool *allow_free)
{
_dispatch_object_debug(channel, "%s", __func__);
if (channel->fd_entry &&
!(channel->atomic_flags & (DIO_CLOSED|DIO_STOPPED))) {
if (channel->fd_entry->path_data) {
// This modification is safe since path_data->channel is checked
// only on close_queue (which is still suspended at this point)
channel->fd_entry->path_data->channel = NULL;
}
// Cleanup handlers will only run when all channels related to this
// fd are complete
_dispatch_fd_entry_release(channel->fd_entry);
}
if (channel->queue) {
dispatch_release(channel->queue);
}
if (channel->barrier_queue) {
dispatch_release(channel->barrier_queue);
}
if (channel->barrier_group) {
dispatch_release(channel->barrier_group);
}
}
static int
_dispatch_io_validate_type(dispatch_io_t channel, mode_t mode)
{
int err = 0;
if (S_ISDIR(mode)) {
err = EISDIR;
} else if (channel->params.type == DISPATCH_IO_RANDOM &&
(S_ISFIFO(mode) || S_ISSOCK(mode))) {
err = ESPIPE;
}
return err;
}
static int
_dispatch_io_get_error(dispatch_operation_t op, dispatch_io_t channel,
bool ignore_closed)
{
// On _any_ queue
int err;
if (op) {
channel = op->channel;
}
if (channel->atomic_flags & (DIO_CLOSED|DIO_STOPPED)) {
if (!ignore_closed || channel->atomic_flags & DIO_STOPPED) {
err = ECANCELED;
} else {
err = 0;
}
} else {
err = op ? op->fd_entry->err : channel->err;
}
return err;
}
#pragma mark -
#pragma mark dispatch_io_channels
dispatch_io_t
dispatch_io_create(dispatch_io_type_t type, dispatch_fd_t fd,
dispatch_queue_t queue, void (^cleanup_handler)(int))
{
if (type != DISPATCH_IO_STREAM && type != DISPATCH_IO_RANDOM) {
return DISPATCH_BAD_INPUT;
}
dispatch_io_t channel = _dispatch_io_create(type);
channel->fd = fd;
_dispatch_channel_debug("create", channel);
channel->fd_actual = fd;
dispatch_suspend(channel->queue);
_dispatch_retain(queue);
_dispatch_retain(channel);
_dispatch_fd_entry_init_async(fd, ^(dispatch_fd_entry_t fd_entry) {
// On barrier queue
int err = fd_entry->err;
if (!err) {
err = _dispatch_io_validate_type(channel, fd_entry->stat.mode);
}
if (!err && type == DISPATCH_IO_RANDOM) {
#if defined(_WIN32)
LARGE_INTEGER liPosition;
LARGE_INTEGER liDistance = {};
if (!SetFilePointerEx((HANDLE)fd_entry->fd, liDistance, &liPosition, FILE_CURRENT)) {
err = (int)GetLastError();
} else {
err = 0;
channel->f_ptr = liPosition.QuadPart;
}
#else
off_t f_ptr;
_dispatch_io_syscall_switch_noerr(err,
f_ptr = lseek(fd_entry->fd, 0, SEEK_CUR),
case 0: channel->f_ptr = f_ptr; break;
default: (void)dispatch_assume_zero(err); break;
);
#endif
}
channel->err = err;
_dispatch_fd_entry_retain(fd_entry);
_dispatch_io_init(channel, fd_entry, queue, err, cleanup_handler);
dispatch_resume(channel->queue);
_dispatch_object_debug(channel, "%s", __func__);
_dispatch_release(channel);
_dispatch_release(queue);
});
_dispatch_object_debug(channel, "%s", __func__);
return channel;
}
dispatch_io_t
dispatch_io_create_f(dispatch_io_type_t type, dispatch_fd_t fd,
dispatch_queue_t queue, void *context,
void (*cleanup_handler)(void *context, int error))
{
return dispatch_io_create(type, fd, queue, !cleanup_handler ? NULL :
^(int error){ cleanup_handler(context, error); });
}
dispatch_io_t
dispatch_io_create_with_path(dispatch_io_type_t type, const char *path,
int oflag, mode_t mode, dispatch_queue_t queue,
void (^cleanup_handler)(int error))
{
if ((type != DISPATCH_IO_STREAM && type != DISPATCH_IO_RANDOM) ||
!(*path == '/')) {
return DISPATCH_BAD_INPUT;
}
size_t pathlen = strlen(path);
dispatch_io_path_data_t path_data = malloc(sizeof(*path_data) + pathlen+1);
if (!path_data) {
return DISPATCH_OUT_OF_MEMORY;
}
dispatch_io_t channel = _dispatch_io_create(type);
channel->fd = -1;
_dispatch_channel_debug("create with path %s", channel, path);
channel->fd_actual = -1;
path_data->channel = channel;
path_data->oflag = oflag;
path_data->mode = mode;
path_data->pathlen = pathlen;
memcpy(path_data->path, path, pathlen + 1);
_dispatch_retain(queue);
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
int err = 0;
struct stat st;
_dispatch_io_syscall_switch_noerr(err,
#if defined(_WIN32)
stat(path_data->path, &st),
#else
(path_data->oflag & O_NOFOLLOW) == O_NOFOLLOW
#if __APPLE__
|| (path_data->oflag & O_SYMLINK) == O_SYMLINK
#endif
? lstat(path_data->path, &st) : stat(path_data->path, &st),
#endif
case 0:
err = _dispatch_io_validate_type(channel, st.st_mode);
break;
default:
if ((path_data->oflag & O_CREAT) &&
(*(path_data->path + path_data->pathlen - 1) != '/')) {
// Check parent directory
char *c = strrchr(path_data->path, '/');
dispatch_assert(c);
*c = 0;
int perr;
_dispatch_io_syscall_switch_noerr(perr,
stat(path_data->path, &st),
case 0:
// Since the parent directory exists, open() will
// create a regular file after the fd_entry has
// been filled in
st.st_mode = S_IFREG;
err = 0;
break;
);
*c = '/';
}
break;
);
channel->err = err;
if (err) {
free(path_data);
_dispatch_io_init(channel, NULL, queue, err, cleanup_handler);
_dispatch_release(channel);
_dispatch_release(queue);
return;
}
dispatch_suspend(channel->queue);
dispatch_once_f(&_dispatch_io_devs_lockq_pred, NULL,
_dispatch_io_devs_lockq_init);
dispatch_async(_dispatch_io_devs_lockq, ^{
dispatch_fd_entry_t fd_entry = _dispatch_fd_entry_create_with_path(
path_data, st.st_dev, st.st_mode);
_dispatch_io_init(channel, fd_entry, queue, 0, cleanup_handler);
dispatch_resume(channel->queue);
_dispatch_object_debug(channel, "%s", __func__);
_dispatch_release(channel);
_dispatch_release(queue);
});
});
_dispatch_object_debug(channel, "%s", __func__);
return channel;
}
dispatch_io_t
dispatch_io_create_with_path_f(dispatch_io_type_t type, const char *path,
int oflag, mode_t mode, dispatch_queue_t queue, void *context,
void (*cleanup_handler)(void *context, int error))
{
return dispatch_io_create_with_path(type, path, oflag, mode, queue,
!cleanup_handler ? NULL :
^(int error){ cleanup_handler(context, error); });
}
dispatch_io_t
dispatch_io_create_with_io(dispatch_io_type_t type, dispatch_io_t in_channel,
dispatch_queue_t queue, void (^cleanup_handler)(int error))
{
if (type != DISPATCH_IO_STREAM && type != DISPATCH_IO_RANDOM) {
return DISPATCH_BAD_INPUT;
}
dispatch_io_t channel = _dispatch_io_create(type);
_dispatch_channel_debug("create with channel %p", channel, in_channel);
dispatch_suspend(channel->queue);
_dispatch_retain(queue);
_dispatch_retain(channel);
_dispatch_retain(in_channel);
dispatch_async(in_channel->queue, ^{
int err0 = _dispatch_io_get_error(NULL, in_channel, false);
if (err0) {
channel->err = err0;
_dispatch_io_init(channel, NULL, queue, err0, cleanup_handler);
dispatch_resume(channel->queue);
_dispatch_release(channel);
_dispatch_release(in_channel);
_dispatch_release(queue);
return;
}
dispatch_async(in_channel->barrier_queue, ^{
int err = _dispatch_io_get_error(NULL, in_channel, false);
// If there is no error, the fd_entry for the in_channel is valid.
// Since we are running on in_channel's queue, the fd_entry has been
// fully resolved and will stay valid for the duration of this block
if (!err) {
err = in_channel->err;
if (!err) {
err = in_channel->fd_entry->err;
}
}
if (!err) {
err = _dispatch_io_validate_type(channel,
in_channel->fd_entry->stat.mode);
}
if (!err && type == DISPATCH_IO_RANDOM && in_channel->fd != -1) {
#if defined(_WIN32)
LARGE_INTEGER liPosition;
LARGE_INTEGER liDistance = {};
if (!SetFilePointerEx((HANDLE)in_channel->fd_entry->fd, liDistance, &liPosition, FILE_CURRENT)) {
err = (int)GetLastError();
} else {
err = 0;
channel->f_ptr = liPosition.QuadPart;
}
#else
off_t f_ptr;
_dispatch_io_syscall_switch_noerr(err,
f_ptr = lseek(in_channel->fd_entry->fd, 0, SEEK_CUR),
case 0: channel->f_ptr = f_ptr; break;
default: (void)dispatch_assume_zero(err); break;
);
#endif
}
channel->err = err;
if (err) {
_dispatch_io_init(channel, NULL, queue, err, cleanup_handler);
dispatch_resume(channel->queue);
_dispatch_release(channel);
_dispatch_release(in_channel);
_dispatch_release(queue);
return;
}
if (in_channel->fd == -1) {
// in_channel was created from path
channel->fd = -1;
channel->fd_actual = -1;
mode_t mode = in_channel->fd_entry->stat.mode;
dev_t dev = in_channel->fd_entry->stat.dev;
size_t path_data_len = sizeof(struct dispatch_io_path_data_s) +
in_channel->fd_entry->path_data->pathlen + 1;
dispatch_io_path_data_t path_data = malloc(path_data_len);
memcpy(path_data, in_channel->fd_entry->path_data,
path_data_len);
path_data->channel = channel;
// lockq_io_devs is known to already exist
dispatch_async(_dispatch_io_devs_lockq, ^{
dispatch_fd_entry_t fd_entry;
fd_entry = _dispatch_fd_entry_create_with_path(path_data,
dev, mode);
_dispatch_io_init(channel, fd_entry, queue, 0,
cleanup_handler);
dispatch_resume(channel->queue);
_dispatch_release(channel);
_dispatch_release(queue);
});
} else {
dispatch_fd_entry_t fd_entry = in_channel->fd_entry;
channel->fd = in_channel->fd;
channel->fd_actual = in_channel->fd_actual;
_dispatch_fd_entry_retain(fd_entry);
_dispatch_io_init(channel, fd_entry, queue, 0, cleanup_handler);
dispatch_resume(channel->queue);
_dispatch_release(channel);
_dispatch_release(queue);
}
_dispatch_release(in_channel);
_dispatch_object_debug(channel, "%s", __func__);
});
});
_dispatch_object_debug(channel, "%s", __func__);
return channel;
}
dispatch_io_t
dispatch_io_create_with_io_f(dispatch_io_type_t type, dispatch_io_t in_channel,
dispatch_queue_t queue, void *context,
void (*cleanup_handler)(void *context, int error))
{
return dispatch_io_create_with_io(type, in_channel, queue,
!cleanup_handler ? NULL :
^(int error){ cleanup_handler(context, error); });
}
#pragma mark -
#pragma mark dispatch_io_accessors
void
dispatch_io_set_high_water(dispatch_io_t channel, size_t high_water)
{
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
_dispatch_channel_debug("set high water: %zu", channel, high_water);
if (channel->params.low > high_water) {
channel->params.low = high_water;
}
channel->params.high = high_water ? high_water : 1;
_dispatch_release(channel);
});
}
void
dispatch_io_set_low_water(dispatch_io_t channel, size_t low_water)
{
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
_dispatch_channel_debug("set low water: %zu", channel, low_water);
if (channel->params.high < low_water) {
channel->params.high = low_water ? low_water : 1;
}
channel->params.low = low_water;
_dispatch_release(channel);
});
}
void
dispatch_io_set_interval(dispatch_io_t channel, uint64_t interval,
unsigned long flags)
{
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
_dispatch_channel_debug("set interval: %llu", channel,
(unsigned long long)interval);
channel->params.interval = interval < INT64_MAX ? interval : INT64_MAX;
channel->params.interval_flags = flags;
_dispatch_release(channel);
});
}
void
_dispatch_io_set_target_queue(dispatch_io_t channel, dispatch_queue_t dq)
{
_dispatch_retain(dq);
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
dispatch_queue_t prev_dq = channel->do_targetq;
channel->do_targetq = dq;
_dispatch_release(prev_dq);
_dispatch_object_debug(channel, "%s", __func__);
_dispatch_release(channel);
});
}
dispatch_fd_t
dispatch_io_get_descriptor(dispatch_io_t channel)
{
if (channel->atomic_flags & (DIO_CLOSED|DIO_STOPPED)) {
return -1;
}
dispatch_fd_t fd = channel->fd_actual;
if (fd == -1 && !_dispatch_io_get_error(NULL, channel, false)) {
dispatch_thread_context_t ctxt =
_dispatch_thread_context_find(_dispatch_io_key);
if (ctxt && ctxt->dtc_io_in_barrier == channel) {
(void)_dispatch_fd_entry_open(channel->fd_entry, channel);
}
}
return channel->fd_actual;
}
#pragma mark -
#pragma mark dispatch_io_operations
static void
_dispatch_io_stop(dispatch_io_t channel)
{
_dispatch_channel_debug("stop", channel);
(void)os_atomic_or2o(channel, atomic_flags, DIO_STOPPED, relaxed);
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
dispatch_async(channel->barrier_queue, ^{
_dispatch_object_debug(channel, "%s", __func__);
dispatch_fd_entry_t fd_entry = channel->fd_entry;
if (fd_entry) {
_dispatch_channel_debug("stop cleanup", channel);
_dispatch_fd_entry_cleanup_operations(fd_entry, channel);
if (!(channel->atomic_flags & DIO_CLOSED)) {
if (fd_entry->path_data) {
fd_entry->path_data->channel = NULL;
}
channel->fd_entry = NULL;
_dispatch_fd_entry_release(fd_entry);
}
} else if (channel->fd != -1) {
// Stop after close, need to check if fd_entry still exists
_dispatch_retain(channel);
dispatch_async(_dispatch_io_fds_lockq, ^{
_dispatch_object_debug(channel, "%s", __func__);
_dispatch_channel_debug("stop cleanup after close",
channel);
dispatch_fd_entry_t fdi;
uintptr_t hash = DIO_HASH(channel->fd);
TAILQ_FOREACH(fdi, &_dispatch_io_fds[hash], fd_list) {
if (fdi->fd == channel->fd) {
_dispatch_fd_entry_cleanup_operations(fdi, channel);
break;
}
}
_dispatch_release(channel);
});
}
_dispatch_release(channel);
});
});
}
void
dispatch_io_close(dispatch_io_t channel, unsigned long flags)
{
if (flags & DISPATCH_IO_STOP) {
// Don't stop an already stopped channel
if (channel->atomic_flags & DIO_STOPPED) {
return;
}
return _dispatch_io_stop(channel);
}
// Don't close an already closed or stopped channel
if (channel->atomic_flags & (DIO_CLOSED|DIO_STOPPED)) {
return;
}
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
dispatch_async(channel->barrier_queue, ^{
_dispatch_object_debug(channel, "%s", __func__);
_dispatch_channel_debug("close", channel);
if (!(channel->atomic_flags & (DIO_CLOSED|DIO_STOPPED))) {
(void)os_atomic_or2o(channel, atomic_flags, DIO_CLOSED,
relaxed);
dispatch_fd_entry_t fd_entry = channel->fd_entry;
if (fd_entry) {
if (fd_entry->path_data) {
fd_entry->path_data->channel = NULL;
}
channel->fd_entry = NULL;
_dispatch_fd_entry_release(fd_entry);
}
}
_dispatch_release(channel);
});
});
}
void
dispatch_io_barrier(dispatch_io_t channel, dispatch_block_t barrier)
{
_dispatch_retain(channel);
dispatch_async(channel->queue, ^{
dispatch_queue_t io_q = channel->do_targetq;
dispatch_queue_t barrier_queue = channel->barrier_queue;
dispatch_group_t barrier_group = channel->barrier_group;
dispatch_async(barrier_queue, ^{
dispatch_suspend(barrier_queue);
dispatch_group_notify(barrier_group, io_q, ^{
dispatch_thread_context_s io_ctxt = {
.dtc_key = _dispatch_io_key,
.dtc_io_in_barrier = channel,
};
_dispatch_object_debug(channel, "%s", __func__);
_dispatch_thread_context_push(&io_ctxt);
barrier();
_dispatch_thread_context_pop(&io_ctxt);
dispatch_resume(barrier_queue);
_dispatch_release(channel);
});
});
});
}
void
dispatch_io_barrier_f(dispatch_io_t channel, void *context,
dispatch_function_t barrier)
{
return dispatch_io_barrier(channel, ^{ barrier(context); });
}
void
dispatch_io_read(dispatch_io_t channel, off_t offset, size_t length,
dispatch_queue_t queue, dispatch_io_handler_t handler)
{
_dispatch_retain(channel);
_dispatch_retain(queue);
dispatch_async(channel->queue, ^{
dispatch_operation_t op;
op = _dispatch_operation_create(DOP_DIR_READ, channel, offset,
length, dispatch_data_empty, queue, handler);
if (op) {
dispatch_queue_t barrier_q = channel->barrier_queue;
dispatch_async(barrier_q, ^{
_dispatch_operation_enqueue(op, DOP_DIR_READ,
dispatch_data_empty);
});
}
_dispatch_release(channel);
_dispatch_release(queue);
});
}
void
dispatch_io_read_f(dispatch_io_t channel, off_t offset, size_t length,
dispatch_queue_t queue, void *context,
dispatch_io_handler_function_t handler)
{
return dispatch_io_read(channel, offset, length, queue,
^(bool done, dispatch_data_t d, int error){
handler(context, done, d, error);
});
}
void
dispatch_io_write(dispatch_io_t channel, off_t offset, dispatch_data_t data,
dispatch_queue_t queue, dispatch_io_handler_t handler)
{
_dispatch_io_data_retain(data);
_dispatch_retain(channel);
_dispatch_retain(queue);
dispatch_async(channel->queue, ^{
dispatch_operation_t op;
op = _dispatch_operation_create(DOP_DIR_WRITE, channel, offset,
dispatch_data_get_size(data), data, queue, handler);
if (op) {
dispatch_queue_t barrier_q = channel->barrier_queue;
dispatch_async(barrier_q, ^{
_dispatch_operation_enqueue(op, DOP_DIR_WRITE, data);
_dispatch_io_data_release(data);
});
} else {
_dispatch_io_data_release(data);
}
_dispatch_release(channel);
_dispatch_release(queue);
});
}
void
dispatch_io_write_f(dispatch_io_t channel, off_t offset, dispatch_data_t data,
dispatch_queue_t queue, void *context,
dispatch_io_handler_function_t handler)
{
return dispatch_io_write(channel, offset, data, queue,
^(bool done, dispatch_data_t d, int error){
handler(context, done, d, error);
});
}
void
dispatch_read(dispatch_fd_t fd, size_t length, dispatch_queue_t queue,
void (^handler)(dispatch_data_t, int))
{
_dispatch_retain(queue);
_dispatch_fd_entry_init_async(fd, ^(dispatch_fd_entry_t fd_entry) {
// On barrier queue
if (fd_entry->err) {
int err = fd_entry->err;
dispatch_async(queue, ^{
_dispatch_fd_debug("convenience handler invoke", fd);
handler(dispatch_data_empty, err);
});
_dispatch_release(queue);
return;
}
// Safe to access fd_entry on barrier queue
dispatch_io_t channel = fd_entry->convenience_channel;
if (!channel) {
channel = _dispatch_io_create(DISPATCH_IO_STREAM);
channel->fd = fd;
channel->fd_actual = fd;
channel->fd_entry = fd_entry;
dispatch_retain(fd_entry->barrier_queue);
dispatch_retain(fd_entry->barrier_group);
channel->barrier_queue = fd_entry->barrier_queue;
channel->barrier_group = fd_entry->barrier_group;
fd_entry->convenience_channel = channel;
}
__block dispatch_data_t deliver_data = dispatch_data_empty;
__block int err = 0;
dispatch_async(fd_entry->close_queue, ^{
dispatch_async(queue, ^{
_dispatch_fd_debug("convenience handler invoke", fd);
handler(deliver_data, err);
_dispatch_io_data_release(deliver_data);
});
_dispatch_release(queue);
});
dispatch_operation_t op =
_dispatch_operation_create(DOP_DIR_READ, channel, 0,
length, dispatch_data_empty,
_dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false),
^(bool done, dispatch_data_t data, int error) {
if (data) {
data = dispatch_data_create_concat(deliver_data, data);
_dispatch_io_data_release(deliver_data);
deliver_data = data;
}
if (done) {
err = error;
}
});
if (op) {
_dispatch_operation_enqueue(op, DOP_DIR_READ, dispatch_data_empty);
}
});
}
void
dispatch_read_f(dispatch_fd_t fd, size_t length, dispatch_queue_t queue,
void *context, void (*handler)(void *, dispatch_data_t, int))
{
return dispatch_read(fd, length, queue, ^(dispatch_data_t d, int error){
handler(context, d, error);
});
}
void
dispatch_write(dispatch_fd_t fd, dispatch_data_t data, dispatch_queue_t queue,
void (^handler)(dispatch_data_t, int))
{
_dispatch_io_data_retain(data);
_dispatch_retain(queue);
_dispatch_fd_entry_init_async(fd, ^(dispatch_fd_entry_t fd_entry) {
// On barrier queue
if (fd_entry->err) {
int err = fd_entry->err;
dispatch_async(queue, ^{
_dispatch_fd_debug("convenience handler invoke", fd);
handler(NULL, err);
});
_dispatch_release(queue);
return;
}
// Safe to access fd_entry on barrier queue
dispatch_io_t channel = fd_entry->convenience_channel;
if (!channel) {
channel = _dispatch_io_create(DISPATCH_IO_STREAM);
channel->fd = fd;
channel->fd_actual = fd;
channel->fd_entry = fd_entry;
dispatch_retain(fd_entry->barrier_queue);
dispatch_retain(fd_entry->barrier_group);
channel->barrier_queue = fd_entry->barrier_queue;
channel->barrier_group = fd_entry->barrier_group;
fd_entry->convenience_channel = channel;
}
__block dispatch_data_t deliver_data = NULL;
__block int err = 0;
dispatch_async(fd_entry->close_queue, ^{
dispatch_async(queue, ^{
_dispatch_fd_debug("convenience handler invoke", fd);
handler(deliver_data, err);
if (deliver_data) {
_dispatch_io_data_release(deliver_data);
}
});
_dispatch_release(queue);
});
dispatch_operation_t op =
_dispatch_operation_create(DOP_DIR_WRITE, channel, 0,
dispatch_data_get_size(data), data,
_dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false),
^(bool done, dispatch_data_t d, int error) {
if (done) {
if (d) {
_dispatch_io_data_retain(d);
deliver_data = d;
}
err = error;
}
});
if (op) {
_dispatch_operation_enqueue(op, DOP_DIR_WRITE, data);
}
_dispatch_io_data_release(data);
});
}
void
dispatch_write_f(dispatch_fd_t fd, dispatch_data_t data, dispatch_queue_t queue,
void *context, void (*handler)(void *, dispatch_data_t, int))
{
return dispatch_write(fd, data, queue, ^(dispatch_data_t d, int error){
handler(context, d, error);
});
}
#pragma mark -
#pragma mark dispatch_operation_t
static dispatch_operation_t
_dispatch_operation_create(dispatch_op_direction_t direction,
dispatch_io_t channel, off_t offset, size_t length,
dispatch_data_t data, dispatch_queue_t queue,
dispatch_io_handler_t handler)
{
// On channel queue
dispatch_assert(direction < DOP_DIR_MAX);
// Safe to call _dispatch_io_get_error() with channel->fd_entry since
// that can only be NULL if atomic_flags are set rdar://problem/8362514
int err = _dispatch_io_get_error(NULL, channel, false);
if (err || !length) {
_dispatch_io_data_retain(data);
_dispatch_retain(queue);
dispatch_async(channel->barrier_queue, ^{
dispatch_async(queue, ^{
dispatch_data_t d = data;
if (direction == DOP_DIR_READ && err) {
d = NULL;
} else if (direction == DOP_DIR_WRITE && !err) {
d = NULL;
}
_dispatch_channel_debug("IO handler invoke: err %d", channel,
err);
handler(true, d, err);
_dispatch_io_data_release(data);
});
_dispatch_release(queue);
});
return NULL;
}
dispatch_operation_t op = _dispatch_object_alloc(DISPATCH_VTABLE(operation),
sizeof(struct dispatch_operation_s));
_dispatch_channel_debug("operation create: %p", channel, op);
op->do_next = DISPATCH_OBJECT_LISTLESS;
op->do_xref_cnt = -1; // operation object is not exposed externally
op->op_q = dispatch_queue_create_with_target("com.apple.libdispatch-io.opq",
NULL, queue);
op->active = false;
op->direction = direction;
op->offset = offset + channel->f_ptr;
op->length = length;
op->handler = _dispatch_io_Block_copy(handler);
_dispatch_retain(channel);
op->channel = channel;
op->params = channel->params;
// Take a snapshot of the priority of the channel queue. The actual I/O
// for this operation will be performed at this priority
dispatch_queue_t targetq = op->channel->do_targetq;
while (fastpath(targetq->do_targetq)) {
targetq = targetq->do_targetq;
}
op->do_targetq = targetq;
_dispatch_object_debug(op, "%s", __func__);
return op;
}
void
_dispatch_operation_dispose(dispatch_operation_t op,
DISPATCH_UNUSED bool *allow_free)
{
_dispatch_object_debug(op, "%s", __func__);
_dispatch_op_debug("dispose", op);
// Deliver the data if there's any
if (op->fd_entry) {
_dispatch_operation_deliver_data(op, DOP_DONE);
dispatch_group_leave(op->fd_entry->barrier_group);
_dispatch_fd_entry_release(op->fd_entry);
}
if (op->channel) {
_dispatch_release(op->channel);
}
if (op->timer) {
dispatch_release(op->timer);
}
// For write operations, op->buf is owned by op->buf_data
if (op->buf && op->direction == DOP_DIR_READ) {
#if defined(_WIN32)
_aligned_free(op->buf);
#else
free(op->buf);
#endif
}
if (op->buf_data) {
_dispatch_io_data_release(op->buf_data);
}
if (op->data) {
_dispatch_io_data_release(op->data);
}
if (op->op_q) {
dispatch_release(op->op_q);
}
Block_release(op->handler);
_dispatch_op_debug("disposed", op);
}
static void
_dispatch_operation_enqueue(dispatch_operation_t op,
dispatch_op_direction_t direction, dispatch_data_t data)
{
// Called from the barrier queue
_dispatch_io_data_retain(data);
// If channel is closed or stopped, then call the handler immediately
int err = _dispatch_io_get_error(NULL, op->channel, false);
if (err) {
dispatch_io_handler_t handler = op->handler;
dispatch_async(op->op_q, ^{
dispatch_data_t d = data;
if (direction == DOP_DIR_READ && err) {
d = NULL;
} else if (direction == DOP_DIR_WRITE && !err) {
d = NULL;
}
handler(true, d, err);
_dispatch_io_data_release(data);
});
_dispatch_op_debug("release -> %d, err %d", op, op->do_ref_cnt, err);
_dispatch_release(op);
return;
}
// Finish operation init
op->fd_entry = op->channel->fd_entry;
_dispatch_fd_entry_retain(op->fd_entry);
dispatch_group_enter(op->fd_entry->barrier_group);
dispatch_disk_t disk = op->fd_entry->disk;
if (!disk) {
dispatch_stream_t stream = op->fd_entry->streams[direction];
dispatch_async(stream->dq, ^{
_dispatch_stream_enqueue_operation(stream, op, data);
_dispatch_io_data_release(data);
});
} else {
dispatch_async(disk->pick_queue, ^{
_dispatch_disk_enqueue_operation(disk, op, data);
_dispatch_io_data_release(data);
});
}
}
static bool
_dispatch_operation_should_enqueue(dispatch_operation_t op,
dispatch_queue_t tq, dispatch_data_t data)
{
// On stream queue or disk queue
_dispatch_op_debug("enqueue", op);
_dispatch_io_data_retain(data);
op->data = data;
int err = _dispatch_io_get_error(op, NULL, true);
if (err) {
op->err = err;
// Final release
_dispatch_op_debug("release -> %d, err %d", op, op->do_ref_cnt, err);
_dispatch_release(op);
return false;
}
if (op->params.interval) {
dispatch_resume(_dispatch_operation_timer(tq, op));
}
return true;
}
static dispatch_source_t
_dispatch_operation_timer(dispatch_queue_t tq, dispatch_operation_t op)
{
// On stream queue or pick queue
if (op->timer) {
return op->timer;
}
dispatch_source_t timer = dispatch_source_create(
DISPATCH_SOURCE_TYPE_TIMER, 0, 0, tq);
dispatch_source_set_timer(timer,
dispatch_time(DISPATCH_TIME_NOW, (int64_t)op->params.interval),
op->params.interval, 0);
dispatch_source_set_event_handler(timer, ^{
// On stream queue or pick queue
if (dispatch_source_testcancel(timer)) {
// Do nothing. The operation has already completed
return;
}
dispatch_op_flags_t flags = DOP_DEFAULT;
if (op->params.interval_flags & DISPATCH_IO_STRICT_INTERVAL) {
// Deliver even if there is less data than the low-water mark
flags |= DOP_DELIVER;
}
// If the operation is active, dont deliver data
if ((op->active) && (flags & DOP_DELIVER)) {
op->flags = flags;
} else {
_dispatch_operation_deliver_data(op, flags);
}
});
op->timer = timer;
return op->timer;
}
#pragma mark -
#pragma mark dispatch_fd_entry_t
#if DISPATCH_USE_GUARDED_FD_CHANGE_FDGUARD
static void
_dispatch_fd_entry_guard(dispatch_fd_entry_t fd_entry)
{
guardid_t guard = fd_entry;
const unsigned int guard_flags = GUARD_CLOSE;
int err, fd_flags = 0;
_dispatch_io_syscall_switch_noerr(err,
change_fdguard_np(fd_entry->fd, NULL, 0, &guard, guard_flags,
&fd_flags),
case 0:
fd_entry->guard_flags = guard_flags;
fd_entry->orig_fd_flags = fd_flags;
break;
case EPERM: break;
default: (void)dispatch_assume_zero(err); break;
);
}
static void
_dispatch_fd_entry_unguard(dispatch_fd_entry_t fd_entry)
{
if (!fd_entry->guard_flags) {
return;
}
guardid_t guard = fd_entry;
int err, fd_flags = fd_entry->orig_fd_flags;
_dispatch_io_syscall_switch(err,
change_fdguard_np(fd_entry->fd, &guard, fd_entry->guard_flags, NULL, 0,
&fd_flags),
default: (void)dispatch_assume_zero(err); break;
);
}
#else
#if !defined(_WIN32)
static inline void
_dispatch_fd_entry_guard(dispatch_fd_entry_t fd_entry) { (void)fd_entry; }
#endif
static inline void
_dispatch_fd_entry_unguard(dispatch_fd_entry_t fd_entry) { (void)fd_entry; }
#endif // DISPATCH_USE_GUARDED_FD
static inline dispatch_fd_t
_dispatch_fd_entry_guarded_open(dispatch_fd_entry_t fd_entry, const char *path,
int oflag, mode_t mode) {
#if DISPATCH_USE_GUARDED_FD
guardid_t guard = (uintptr_t)fd_entry;
const unsigned int guard_flags = GUARD_CLOSE | GUARD_DUP |
GUARD_SOCKET_IPC | GUARD_FILEPORT;
int fd = guarded_open_np(path, &guard, guard_flags, oflag | O_CLOEXEC,
mode);
if (fd != -1) {
fd_entry->guard_flags = guard_flags;
return fd;
}
errno = 0;
#else
(void)fd_entry;
#endif
#if defined(_WIN32)
(void)mode;
DWORD dwDesiredAccess = 0;
if (oflag & _O_RDWR)
dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
else if (oflag & _O_RDONLY)
dwDesiredAccess = GENERIC_READ;
else if (oflag & _O_WRONLY)
dwDesiredAccess = GENERIC_WRITE;
DWORD dwCreationDisposition = OPEN_EXISTING;
if (oflag & _O_CREAT)
dwCreationDisposition = OPEN_ALWAYS;
if (oflag & _O_TRUNC)
dwCreationDisposition = CREATE_ALWAYS;
return (dispatch_fd_t)CreateFile(path, dwDesiredAccess, 0, NULL, dwCreationDisposition, 0, NULL);
#else
return open(path, oflag, mode);
#endif
}
static inline int
_dispatch_fd_entry_guarded_close(dispatch_fd_entry_t fd_entry, dispatch_fd_t fd) {
#if DISPATCH_USE_GUARDED_FD
if (fd_entry->guard_flags) {
guardid_t guard = (uintptr_t)fd_entry;
return guarded_close_np(fd, &guard);
} else
#else
(void)fd_entry;
#endif
{
#if defined(_WIN32)
return CloseHandle((HANDLE)fd);
#else
return close(fd);
#endif
}
}
static inline void
_dispatch_fd_entry_retain(dispatch_fd_entry_t fd_entry) {
dispatch_suspend(fd_entry->close_queue);
}
static inline void
_dispatch_fd_entry_release(dispatch_fd_entry_t fd_entry) {
dispatch_resume(fd_entry->close_queue);
}
static void
_dispatch_fd_entry_init_async(dispatch_fd_t fd,
dispatch_fd_entry_init_callback_t completion_callback)
{
static dispatch_once_t _dispatch_io_fds_lockq_pred;
dispatch_once_f(&_dispatch_io_fds_lockq_pred, NULL,
_dispatch_io_fds_lockq_init);
dispatch_async(_dispatch_io_fds_lockq, ^{
dispatch_fd_entry_t fd_entry = NULL;
// Check to see if there is an existing entry for the given fd
uintptr_t hash = DIO_HASH(fd);
TAILQ_FOREACH(fd_entry, &_dispatch_io_fds[hash], fd_list) {
if (fd_entry->fd == fd) {
// Retain the fd_entry to ensure it cannot go away until the
// stat() has completed
_dispatch_fd_entry_retain(fd_entry);
break;
}
}
if (!fd_entry) {
// If we did not find an existing entry, create one
fd_entry = _dispatch_fd_entry_create_with_fd(fd, hash);
}
_dispatch_fd_entry_debug("init", fd_entry);
dispatch_async(fd_entry->barrier_queue, ^{
_dispatch_fd_entry_debug("init completion", fd_entry);
completion_callback(fd_entry);
// stat() is complete, release reference to fd_entry
_dispatch_fd_entry_release(fd_entry);
});
});
}
static dispatch_fd_entry_t
_dispatch_fd_entry_create(dispatch_queue_t q)
{
dispatch_fd_entry_t fd_entry;
fd_entry = _dispatch_calloc(1ul, sizeof(struct dispatch_fd_entry_s));
// Use target queue to ensure that no concurrent lookups are going on when
// the close queue is running
fd_entry->close_queue = dispatch_queue_create_with_target(
"com.apple.libdispatch-io.closeq", NULL, q);
// Suspend the cleanup queue until closing
_dispatch_fd_entry_retain(fd_entry);
return fd_entry;
}
static dispatch_fd_entry_t
_dispatch_fd_entry_create_with_fd(dispatch_fd_t fd, uintptr_t hash)
{
// On fds lock queue
dispatch_fd_entry_t fd_entry = _dispatch_fd_entry_create(
_dispatch_io_fds_lockq);
_dispatch_fd_entry_debug("create: fd %d", fd_entry, fd);
fd_entry->fd = fd;
TAILQ_INSERT_TAIL(&_dispatch_io_fds[hash], fd_entry, fd_list);
fd_entry->barrier_queue = dispatch_queue_create(
"com.apple.libdispatch-io.barrierq", NULL);
fd_entry->barrier_group = dispatch_group_create();
dispatch_async(fd_entry->barrier_queue, ^{
#if defined(_WIN32)
DWORD dwType = GetFileType((HANDLE)fd);
if (dwType == FILE_TYPE_PIPE) {
unsigned long value = 1;
int result = ioctlsocket((SOCKET)fd, (long)FIONBIO, &value);
(void)dispatch_assume_zero(result);
_dispatch_stream_init(fd_entry,
_dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false));
} else {
dispatch_suspend(fd_entry->barrier_queue);
dispatch_once_f(&_dispatch_io_devs_lockq_pred, NULL,
_dispatch_io_devs_lockq_init);
dispatch_async(_dispatch_io_devs_lockq, ^{
_dispatch_disk_init(fd_entry, 0);
dispatch_resume(fd_entry->barrier_queue);
});
}
#else
_dispatch_fd_entry_debug("stat", fd_entry);
int err, orig_flags, orig_nosigpipe = -1;
struct stat st;
_dispatch_io_syscall_switch(err,
fstat(fd, &st),
default: fd_entry->err = err; return;
);
fd_entry->stat.dev = st.st_dev;
fd_entry->stat.mode = st.st_mode;
_dispatch_fd_entry_guard(fd_entry);
_dispatch_io_syscall_switch(err,
orig_flags = fcntl(fd, F_GETFL),
default: (void)dispatch_assume_zero(err); break;
);
#if DISPATCH_USE_SETNOSIGPIPE // rdar://problem/4121123
if (S_ISFIFO(st.st_mode)) {
_dispatch_io_syscall_switch(err,
orig_nosigpipe = fcntl(fd, F_GETNOSIGPIPE),
default: (void)dispatch_assume_zero(err); break;
);
if (orig_nosigpipe != -1) {
_dispatch_io_syscall_switch(err,
orig_nosigpipe = fcntl(fd, F_SETNOSIGPIPE, 1),
default:
orig_nosigpipe = -1;
(void)dispatch_assume_zero(err);
break;
);
}
}
#endif
if (S_ISREG(st.st_mode)) {
if (orig_flags != -1) {
_dispatch_io_syscall_switch(err,
fcntl(fd, F_SETFL, orig_flags & ~O_NONBLOCK),
default:
orig_flags = -1;
(void)dispatch_assume_zero(err);
break;
);
}
dev_t dev = (dev_t)major(st.st_dev);
// We have to get the disk on the global dev queue. The
// barrier queue cannot continue until that is complete
dispatch_suspend(fd_entry->barrier_queue);
dispatch_once_f(&_dispatch_io_devs_lockq_pred, NULL,
_dispatch_io_devs_lockq_init);
dispatch_async(_dispatch_io_devs_lockq, ^{
_dispatch_disk_init(fd_entry, dev);
dispatch_resume(fd_entry->barrier_queue);
});
} else {
if (orig_flags != -1) {
_dispatch_io_syscall_switch(err,
fcntl(fd, F_SETFL, orig_flags | O_NONBLOCK),
default:
orig_flags = -1;
(void)dispatch_assume_zero(err);
break;
);
}
_dispatch_stream_init(fd_entry,
_dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false));
}
fd_entry->orig_flags = orig_flags;
fd_entry->orig_nosigpipe = orig_nosigpipe;
#endif
});
// This is the first item run when the close queue is resumed, indicating
// that all channels associated with this entry have been closed and that
// all operations associated with this entry have been freed
dispatch_async(fd_entry->close_queue, ^{
if (!fd_entry->disk) {
_dispatch_fd_entry_debug("close queue cleanup", fd_entry);
dispatch_op_direction_t dir;
for (dir = 0; dir < DOP_DIR_MAX; dir++) {
_dispatch_stream_dispose(fd_entry, dir);
}
} else {
dispatch_disk_t disk = fd_entry->disk;
dispatch_async(_dispatch_io_devs_lockq, ^{
_dispatch_release(disk);
});
}
// Remove this entry from the global fd list
TAILQ_REMOVE(&_dispatch_io_fds[hash], fd_entry, fd_list);
});
// If there was a source associated with this stream, disposing of the
// source cancels it and suspends the close queue. Freeing the fd_entry
// structure must happen after the source cancel handler has finished
dispatch_async(fd_entry->close_queue, ^{
_dispatch_fd_entry_debug("close queue release", fd_entry);
dispatch_release(fd_entry->close_queue);
_dispatch_fd_entry_debug("barrier queue release", fd_entry);
dispatch_release(fd_entry->barrier_queue);
_dispatch_fd_entry_debug("barrier group release", fd_entry);
dispatch_release(fd_entry->barrier_group);
#if !defined(_WIN32)
if (fd_entry->orig_flags != -1) {
_dispatch_io_syscall(
fcntl(fd, F_SETFL, fd_entry->orig_flags)
);
}
#if DISPATCH_USE_SETNOSIGPIPE // rdar://problem/4121123
if (fd_entry->orig_nosigpipe != -1) {
_dispatch_io_syscall(
fcntl(fd, F_SETNOSIGPIPE, fd_entry->orig_nosigpipe)
);
}
#endif
#endif
_dispatch_fd_entry_unguard(fd_entry);
if (fd_entry->convenience_channel) {
fd_entry->convenience_channel->fd_entry = NULL;
dispatch_release(fd_entry->convenience_channel);
}
free(fd_entry);
});
return fd_entry;
}
static dispatch_fd_entry_t
_dispatch_fd_entry_create_with_path(dispatch_io_path_data_t path_data,
dev_t dev, mode_t mode)
{
// On devs lock queue
dispatch_fd_entry_t fd_entry = _dispatch_fd_entry_create(
path_data->channel->queue);
_dispatch_fd_entry_debug("create: path %s", fd_entry, path_data->path);
if (S_ISREG(mode)) {
#if defined(_WIN32)
_dispatch_disk_init(fd_entry, 0);
#else
_dispatch_disk_init(fd_entry, (dev_t)major(dev));
#endif
} else {
_dispatch_stream_init(fd_entry,
_dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false));
}
fd_entry->fd = -1;
fd_entry->orig_flags = -1;
fd_entry->path_data = path_data;
fd_entry->stat.dev = dev;
fd_entry->stat.mode = mode;
fd_entry->barrier_queue = dispatch_queue_create(
"com.apple.libdispatch-io.barrierq", NULL);
fd_entry->barrier_group = dispatch_group_create();
// This is the first item run when the close queue is resumed, indicating
// that the channel associated with this entry has been closed and that
// all operations associated with this entry have been freed
dispatch_async(fd_entry->close_queue, ^{
_dispatch_fd_entry_debug("close queue cleanup", fd_entry);
if (!fd_entry->disk) {
dispatch_op_direction_t dir;
for (dir = 0; dir < DOP_DIR_MAX; dir++) {
_dispatch_stream_dispose(fd_entry, dir);
}
}
if (fd_entry->fd != -1) {
_dispatch_fd_entry_guarded_close(fd_entry, fd_entry->fd);
}
if (fd_entry->path_data->channel) {
// If associated channel has not been released yet, mark it as
// no longer having an fd_entry (for stop after close).
// It is safe to modify channel since we are on close_queue with
// target queue the channel queue
fd_entry->path_data->channel->fd_entry = NULL;
}
});
dispatch_async(fd_entry->close_queue, ^{
_dispatch_fd_entry_debug("close queue release", fd_entry);
dispatch_release(fd_entry->close_queue);
dispatch_release(fd_entry->barrier_queue);
dispatch_release(fd_entry->barrier_group);
free(fd_entry->path_data);
free(fd_entry);
});
return fd_entry;
}
static int
_dispatch_fd_entry_open(dispatch_fd_entry_t fd_entry, dispatch_io_t channel)
{
if (!(fd_entry->fd == -1 && fd_entry->path_data)) {
return 0;
}
if (fd_entry->err) {
return fd_entry->err;
}
dispatch_fd_t fd = -1;
int oflag = fd_entry->disk ? fd_entry->path_data->oflag & ~O_NONBLOCK :
fd_entry->path_data->oflag | O_NONBLOCK;
open:
fd = _dispatch_fd_entry_guarded_open(fd_entry, fd_entry->path_data->path,
oflag, fd_entry->path_data->mode);
if (fd == -1) {
int err = errno;
if (err == EINTR) {
goto open;
}
(void)os_atomic_cmpxchg2o(fd_entry, err, 0, err, relaxed);
return err;
}
if (!os_atomic_cmpxchg2o(fd_entry, fd, -1, fd, relaxed)) {
// Lost the race with another open
_dispatch_fd_entry_guarded_close(fd_entry, fd);
} else {
channel->fd_actual = fd;
}
_dispatch_object_debug(channel, "%s", __func__);
return 0;
}
static void
_dispatch_fd_entry_cleanup_operations(dispatch_fd_entry_t fd_entry,
dispatch_io_t channel)
{
if (fd_entry->disk) {
if (channel) {
_dispatch_retain(channel);
}
_dispatch_fd_entry_retain(fd_entry);
dispatch_async(fd_entry->disk->pick_queue, ^{
_dispatch_disk_cleanup_inactive_operations(fd_entry->disk, channel);
_dispatch_fd_entry_release(fd_entry);
if (channel) {
_dispatch_release(channel);
}
});
} else {
dispatch_op_direction_t direction;
for (direction = 0; direction < DOP_DIR_MAX; direction++) {
dispatch_stream_t stream = fd_entry->streams[direction];
if (!stream) {
continue;
}
if (channel) {
_dispatch_retain(channel);
}
_dispatch_fd_entry_retain(fd_entry);
dispatch_async(stream->dq, ^{
_dispatch_stream_cleanup_operations(stream, channel);
_dispatch_fd_entry_release(fd_entry);
if (channel) {
_dispatch_release(channel);
}
});
}
}
}
#pragma mark -
#pragma mark dispatch_stream_t/dispatch_disk_t
static void
_dispatch_stream_init(dispatch_fd_entry_t fd_entry, dispatch_queue_t tq)
{
dispatch_op_direction_t direction;
for (direction = 0; direction < DOP_DIR_MAX; direction++) {
dispatch_stream_t stream;
stream = _dispatch_calloc(1ul, sizeof(struct dispatch_stream_s));
stream->dq = dispatch_queue_create_with_target(
"com.apple.libdispatch-io.streamq", NULL, tq);
dispatch_set_context(stream->dq, stream);
TAILQ_INIT(&stream->operations[DISPATCH_IO_RANDOM]);
TAILQ_INIT(&stream->operations[DISPATCH_IO_STREAM]);
fd_entry->streams[direction] = stream;
}
}
static void
_dispatch_stream_dispose(dispatch_fd_entry_t fd_entry,
dispatch_op_direction_t direction)
{
// On close queue
dispatch_stream_t stream = fd_entry->streams[direction];
if (!stream) {
return;
}
dispatch_assert(TAILQ_EMPTY(&stream->operations[DISPATCH_IO_STREAM]));
dispatch_assert(TAILQ_EMPTY(&stream->operations[DISPATCH_IO_RANDOM]));
if (stream->source) {
// Balanced by source cancel handler:
_dispatch_fd_entry_retain(fd_entry);
dispatch_source_cancel(stream->source);
dispatch_resume(stream->source);
dispatch_release(stream->source);
}
dispatch_set_context(stream->dq, NULL);
dispatch_release(stream->dq);
free(stream);
}
static void
_dispatch_disk_init(dispatch_fd_entry_t fd_entry, dev_t dev)
{
// On devs lock queue
dispatch_disk_t disk;
// Check to see if there is an existing entry for the given device
uintptr_t hash = DIO_HASH(dev);
TAILQ_FOREACH(disk, &_dispatch_io_devs[hash], disk_list) {
if (disk->dev == dev) {
_dispatch_retain(disk);
goto out;
}
}
// Otherwise create a new entry
size_t pending_reqs_depth = dispatch_io_defaults.max_pending_io_reqs;
disk = _dispatch_object_alloc(DISPATCH_VTABLE(disk),
sizeof(struct dispatch_disk_s) +
(pending_reqs_depth * sizeof(dispatch_operation_t)));
disk->do_next = DISPATCH_OBJECT_LISTLESS;
disk->do_xref_cnt = -1;
disk->advise_list_depth = pending_reqs_depth;
disk->do_targetq = _dispatch_get_root_queue(DISPATCH_QOS_DEFAULT, false);
disk->dev = dev;
TAILQ_INIT(&disk->operations);
disk->cur_rq = TAILQ_FIRST(&disk->operations);
char label[45];
snprintf(label, sizeof(label), "com.apple.libdispatch-io.deviceq.%d",
(int)dev);
disk->pick_queue = dispatch_queue_create(label, NULL);
TAILQ_INSERT_TAIL(&_dispatch_io_devs[hash], disk, disk_list);
out:
fd_entry->disk = disk;
TAILQ_INIT(&fd_entry->stream_ops);
}
void
_dispatch_disk_dispose(dispatch_disk_t disk, DISPATCH_UNUSED bool *allow_free)
{
uintptr_t hash = DIO_HASH(disk->dev);
TAILQ_REMOVE(&_dispatch_io_devs[hash], disk, disk_list);
dispatch_assert(TAILQ_EMPTY(&disk->operations));
size_t i;
for (i=0; i<disk->advise_list_depth; ++i) {
dispatch_assert(!disk->advise_list[i]);
}
dispatch_release(disk->pick_queue);
}
#pragma mark -
#pragma mark dispatch_stream_operations/dispatch_disk_operations
static inline bool
_dispatch_stream_operation_avail(dispatch_stream_t stream)
{
return !(TAILQ_EMPTY(&stream->operations[DISPATCH_IO_RANDOM])) ||
!(TAILQ_EMPTY(&stream->operations[DISPATCH_IO_STREAM]));
}
static void
_dispatch_stream_enqueue_operation(dispatch_stream_t stream,
dispatch_operation_t op, dispatch_data_t data)
{
if (!_dispatch_operation_should_enqueue(op, stream->dq, data)) {
return;
}
_dispatch_object_debug(op, "%s", __func__);
bool no_ops = !_dispatch_stream_operation_avail(stream);
TAILQ_INSERT_TAIL(&stream->operations[op->params.type], op, operation_list);
if (no_ops) {
dispatch_async_f(stream->dq, stream->dq,
_dispatch_stream_queue_handler);
}
}
static void
_dispatch_disk_enqueue_operation(dispatch_disk_t disk, dispatch_operation_t op,
dispatch_data_t data)
{
if (!_dispatch_operation_should_enqueue(op, disk->pick_queue, data)) {
return;
}
_dispatch_object_debug(op, "%s", __func__);
if (op->params.type == DISPATCH_IO_STREAM) {
if (TAILQ_EMPTY(&op->fd_entry->stream_ops)) {
TAILQ_INSERT_TAIL(&disk->operations, op, operation_list);
}
TAILQ_INSERT_TAIL(&op->fd_entry->stream_ops, op, stream_list);
} else {
TAILQ_INSERT_TAIL(&disk->operations, op, operation_list);
}
_dispatch_disk_handler(disk);
}
static void
_dispatch_stream_complete_operation(dispatch_stream_t stream,
dispatch_operation_t op)
{
// On stream queue
_dispatch_object_debug(op, "%s", __func__);
_dispatch_op_debug("complete: stream %p", op, stream);
TAILQ_REMOVE(&stream->operations[op->params.type], op, operation_list);
if (op == stream->op) {
stream->op = NULL;
}
if (op->timer) {
dispatch_source_cancel(op->timer);
}
// Final release will deliver any pending data
_dispatch_op_debug("release -> %d (stream complete)", op, op->do_ref_cnt);
_dispatch_release(op);
}
static void
_dispatch_disk_complete_operation(dispatch_disk_t disk, dispatch_operation_t op)
{
// On pick queue
_dispatch_object_debug(op, "%s", __func__);
_dispatch_op_debug("complete: disk %p", op, disk);
// Current request is always the last op returned
if (disk->cur_rq == op) {
disk->cur_rq = TAILQ_PREV(op, dispatch_disk_operations_s,
operation_list);
}
if (op->params.type == DISPATCH_IO_STREAM) {
// Check if there are other pending stream operations behind it
dispatch_operation_t op_next = TAILQ_NEXT(op, stream_list);
TAILQ_REMOVE(&op->fd_entry->stream_ops, op, stream_list);
if (op_next) {
TAILQ_INSERT_TAIL(&disk->operations, op_next, operation_list);
}
}
TAILQ_REMOVE(&disk->operations, op, operation_list);
if (op->timer) {
dispatch_source_cancel(op->timer);
}
// Final release will deliver any pending data
_dispatch_op_debug("release -> %d (disk complete)", op, op->do_ref_cnt);
_dispatch_release(op);
}
static dispatch_operation_t
_dispatch_stream_pick_next_operation(dispatch_stream_t stream,
dispatch_operation_t op)
{
// On stream queue
if (!op) {
// On the first run through, pick the first operation
if (!_dispatch_stream_operation_avail(stream)) {
return op;
}
if (!TAILQ_EMPTY(&stream->operations[DISPATCH_IO_STREAM])) {
op = TAILQ_FIRST(&stream->operations[DISPATCH_IO_STREAM]);
} else if (!TAILQ_EMPTY(&stream->operations[DISPATCH_IO_RANDOM])) {
op = TAILQ_FIRST(&stream->operations[DISPATCH_IO_RANDOM]);
}
return op;
}
if (op->params.type == DISPATCH_IO_STREAM) {
// Stream operations need to be serialized so continue the current
// operation until it is finished
return op;
}
// Get the next random operation (round-robin)
if (op->params.type == DISPATCH_IO_RANDOM) {
op = TAILQ_NEXT(op, operation_list);
if (!op) {
op = TAILQ_FIRST(&stream->operations[DISPATCH_IO_RANDOM]);
}
return op;
}
return NULL;
}
static dispatch_operation_t
_dispatch_disk_pick_next_operation(dispatch_disk_t disk)
{
// On pick queue
dispatch_operation_t op;
if (!TAILQ_EMPTY(&disk->operations)) {
if (disk->cur_rq == NULL) {
op = TAILQ_FIRST(&disk->operations);
} else {
op = disk->cur_rq;
do {
op = TAILQ_NEXT(op, operation_list);
if (!op) {
op = TAILQ_FIRST(&disk->operations);
}
// TODO: more involved picking algorithm rdar://problem/8780312
} while (op->active && op != disk->cur_rq);
}
if (!op->active) {
disk->cur_rq = op;
return op;
}
}
return NULL;
}
static void
_dispatch_stream_cleanup_operations(dispatch_stream_t stream,
dispatch_io_t channel)
{
// On stream queue
dispatch_operation_t op, tmp;
__typeof__(*stream->operations) *operations;
operations = &stream->operations[DISPATCH_IO_RANDOM];
TAILQ_FOREACH_SAFE(op, operations, operation_list, tmp) {
if (!channel || op->channel == channel) {
_dispatch_stream_complete_operation(stream, op);
}
}
operations = &stream->operations[DISPATCH_IO_STREAM];
TAILQ_FOREACH_SAFE(op, operations, operation_list, tmp) {
if (!channel || op->channel == channel) {
_dispatch_stream_complete_operation(stream, op);
}
}
if (stream->source_running && !_dispatch_stream_operation_avail(stream)) {
dispatch_suspend(stream->source);
stream->source_running = false;
}
}
static inline void
_dispatch_disk_cleanup_specified_operations(dispatch_disk_t disk,
dispatch_io_t channel, bool inactive_only)
{
// On pick queue
dispatch_operation_t op, tmp;
TAILQ_FOREACH_SAFE(op, &disk->operations, operation_list, tmp) {
if (inactive_only && op->active) continue;
if (!channel || op->channel == channel) {
_dispatch_op_debug("cleanup: disk %p", op, disk);
_dispatch_disk_complete_operation(disk, op);
}
}
}
static void
_dispatch_disk_cleanup_operations(dispatch_disk_t disk, dispatch_io_t channel)
{
_dispatch_disk_cleanup_specified_operations(disk, channel, false);
}
static void
_dispatch_disk_cleanup_inactive_operations(dispatch_disk_t disk,
dispatch_io_t channel)
{
_dispatch_disk_cleanup_specified_operations(disk, channel, true);
}
#pragma mark -
#pragma mark dispatch_stream_handler/dispatch_disk_handler
static dispatch_source_t
_dispatch_stream_source(dispatch_stream_t stream, dispatch_operation_t op)
{
// On stream queue
if (stream->source) {
return stream->source;
}
dispatch_fd_t fd = op->fd_entry->fd;
_dispatch_op_debug("stream source create", op);
dispatch_source_t source = NULL;
if (op->direction == DOP_DIR_READ) {
source = dispatch_source_create(DISPATCH_SOURCE_TYPE_READ,
(uintptr_t)fd, 0, stream->dq);
} else if (op->direction == DOP_DIR_WRITE) {
source = dispatch_source_create(DISPATCH_SOURCE_TYPE_WRITE,
(uintptr_t)fd, 0, stream->dq);
} else {
dispatch_assert(op->direction < DOP_DIR_MAX);
return NULL;
}
dispatch_set_context(source, stream);
dispatch_source_set_event_handler_f(source,
_dispatch_stream_source_handler);
// Close queue must not run user cleanup handlers until sources are fully
// unregistered
dispatch_queue_t close_queue = op->fd_entry->close_queue;
dispatch_source_set_mandatory_cancel_handler(source, ^{
_dispatch_op_debug("stream source cancel", op);
dispatch_resume(close_queue);
});
stream->source = source;
return stream->source;
}
static void
_dispatch_stream_source_handler(void *ctx)
{
// On stream queue
dispatch_stream_t stream = (dispatch_stream_t)ctx;
dispatch_suspend(stream->source);
stream->source_running = false;
return _dispatch_stream_handler(stream);
}
static void
_dispatch_stream_queue_handler(void *ctx)
{
// On stream queue
dispatch_stream_t stream = (dispatch_stream_t)dispatch_get_context(ctx);
if (!stream) {
// _dispatch_stream_dispose has been called
return;
}
return _dispatch_stream_handler(stream);
}
static void
_dispatch_stream_handler(void *ctx)
{
// On stream queue
dispatch_stream_t stream = (dispatch_stream_t)ctx;
dispatch_operation_t op;
pick:
op = _dispatch_stream_pick_next_operation(stream, stream->op);
if (!op) {
_dispatch_debug("no operation found: stream %p", stream);
return;
}
int err = _dispatch_io_get_error(op, NULL, true);
if (err) {
op->err = err;
_dispatch_stream_complete_operation(stream, op);
goto pick;
}
stream->op = op;
_dispatch_op_debug("stream handler", op);
dispatch_fd_entry_t fd_entry = op->fd_entry;
_dispatch_fd_entry_retain(fd_entry);
// For performance analysis
if (!op->total && dispatch_io_defaults.initial_delivery) {
// Empty delivery to signal the start of the operation
_dispatch_op_debug("initial delivery", op);
_dispatch_operation_deliver_data(op, DOP_DELIVER);
}
// TODO: perform on the operation target queue to get correct priority
int result = _dispatch_operation_perform(op);
dispatch_op_flags_t flags = ~0u;
switch (result) {
case DISPATCH_OP_DELIVER:
flags = DOP_DEFAULT;
// Fall through
case DISPATCH_OP_DELIVER_AND_COMPLETE:
flags = (flags != DOP_DEFAULT) ? DOP_DELIVER | DOP_NO_EMPTY :
DOP_DEFAULT;
_dispatch_operation_deliver_data(op, flags);
// Fall through
case DISPATCH_OP_COMPLETE:
if (flags != DOP_DEFAULT) {
_dispatch_stream_complete_operation(stream, op);
}
if (_dispatch_stream_operation_avail(stream)) {
dispatch_async_f(stream->dq, stream->dq,
_dispatch_stream_queue_handler);
}
break;
case DISPATCH_OP_COMPLETE_RESUME:
_dispatch_stream_complete_operation(stream, op);
// Fall through
case DISPATCH_OP_RESUME:
if (_dispatch_stream_operation_avail(stream)) {
stream->source_running = true;
dispatch_resume(_dispatch_stream_source(stream, op));
}
break;
case DISPATCH_OP_ERR:
_dispatch_stream_cleanup_operations(stream, op->channel);
break;
case DISPATCH_OP_FD_ERR:
_dispatch_fd_entry_retain(fd_entry);
dispatch_async(fd_entry->barrier_queue, ^{
_dispatch_fd_entry_cleanup_operations(fd_entry, NULL);
_dispatch_fd_entry_release(fd_entry);
});
break;
default:
break;
}
_dispatch_fd_entry_release(fd_entry);
return;
}
static void
_dispatch_disk_handler(void *ctx)
{
// On pick queue
dispatch_disk_t disk = (dispatch_disk_t)ctx;
if (disk->io_active) {
return;
}
_dispatch_disk_debug("disk handler", disk);
dispatch_operation_t op;
size_t i = disk->free_idx, j = disk->req_idx;
if (j <= i) {
j += disk->advise_list_depth;
}
while (i <= j) {
if ((!disk->advise_list[i%disk->advise_list_depth]) &&
(op = _dispatch_disk_pick_next_operation(disk))) {
int err = _dispatch_io_get_error(op, NULL, true);
if (err) {
op->err = err;
_dispatch_disk_complete_operation(disk, op);
continue;
}
_dispatch_retain(op);
_dispatch_op_debug("retain -> %d", op, op->do_ref_cnt + 1);
disk->advise_list[i%disk->advise_list_depth] = op;
op->active = true;
_dispatch_op_debug("activate: disk %p", op, disk);
_dispatch_object_debug(op, "%s", __func__);
} else {
// No more operations to get
break;
}
i++;
}
disk->free_idx = (i%disk->advise_list_depth);
op = disk->advise_list[disk->req_idx];
if (op) {
disk->io_active = true;
_dispatch_op_debug("async perform: disk %p", op, disk);
dispatch_async_f(op->do_targetq, disk, _dispatch_disk_perform);
}
}
static void
_dispatch_disk_perform(void *ctxt)
{
dispatch_disk_t disk = ctxt;
_dispatch_disk_debug("disk perform", disk);
size_t chunk_size = dispatch_io_defaults.chunk_size;
dispatch_operation_t op;
size_t i = disk->advise_idx, j = disk->free_idx;
if (j <= i) {
j += disk->advise_list_depth;
}
do {
op = disk->advise_list[i%disk->advise_list_depth];
if (!op) {
// Nothing more to advise, must be at free_idx
dispatch_assert(i%disk->advise_list_depth == disk->free_idx);
break;
}
if (op->direction == DOP_DIR_WRITE) {
// TODO: preallocate writes ? rdar://problem/9032172
continue;
}
if (op->fd_entry->fd == -1 && _dispatch_fd_entry_open(op->fd_entry,
op->channel)) {
continue;
}
// For performance analysis
if (!op->total && dispatch_io_defaults.initial_delivery) {
// Empty delivery to signal the start of the operation
_dispatch_op_debug("initial delivery", op);
_dispatch_operation_deliver_data(op, DOP_DELIVER);
}
// Advise two chunks if the list only has one element and this is the
// first advise on the operation
if ((j-i) == 1 && !disk->advise_list[disk->free_idx] &&
!op->advise_offset) {
chunk_size *= 2;
}
_dispatch_operation_advise(op, chunk_size);
} while (++i < j);
disk->advise_idx = i%disk->advise_list_depth;
op = disk->advise_list[disk->req_idx];
int result = _dispatch_operation_perform(op);
disk->advise_list[disk->req_idx] = NULL;
disk->req_idx = (++disk->req_idx)%disk->advise_list_depth;
_dispatch_op_debug("async perform completion: disk %p", op, disk);
dispatch_async(disk->pick_queue, ^{
_dispatch_op_debug("perform completion", op);
switch (result) {
case DISPATCH_OP_DELIVER:
_dispatch_operation_deliver_data(op, DOP_DEFAULT);
break;
case DISPATCH_OP_COMPLETE:
_dispatch_disk_complete_operation(disk, op);
break;
case DISPATCH_OP_DELIVER_AND_COMPLETE:
_dispatch_operation_deliver_data(op, DOP_DELIVER | DOP_NO_EMPTY);
_dispatch_disk_complete_operation(disk, op);
break;
case DISPATCH_OP_ERR:
_dispatch_disk_cleanup_operations(disk, op->channel);
break;
case DISPATCH_OP_FD_ERR:
_dispatch_disk_cleanup_operations(disk, NULL);
break;
default:
dispatch_assert(result);
break;
}
_dispatch_op_debug("deactivate: disk %p", op, disk);
op->active = false;
disk->io_active = false;
_dispatch_disk_handler(disk);
// Balancing the retain in _dispatch_disk_handler. Note that op must be
// released at the very end, since it might hold the last reference to
// the disk
_dispatch_op_debug("release -> %d (disk perform complete)", op,
op->do_ref_cnt);
_dispatch_release(op);
});
}
#pragma mark -
#pragma mark dispatch_operation_perform
static void
_dispatch_operation_advise(dispatch_operation_t op, size_t chunk_size)
{
_dispatch_op_debug("advise", op);
#if defined(_WIN32)
(void)op;
(void)chunk_size;
#else
if (_dispatch_io_get_error(op, NULL, true)) return;
#if defined(__linux__) || defined(__FreeBSD__)
// linux does not support fcntl (F_RDAVISE)
// define necessary datastructure and use readahead
struct radvisory {
off_t ra_offset;
int ra_count;
};
#endif
int err;
struct radvisory advise;
// No point in issuing a read advise for the next chunk if we are already
// a chunk ahead from reading the bytes
if (op->advise_offset > (off_t)(((size_t)op->offset + op->total) +
chunk_size + PAGE_SIZE)) {
return;
}
_dispatch_object_debug(op, "%s", __func__);
advise.ra_count = (int)chunk_size;
if (!op->advise_offset) {
op->advise_offset = op->offset;
// If this is the first time through, align the advised range to a
// page boundary
size_t pg_fraction = ((size_t)op->offset + chunk_size) % PAGE_SIZE;
advise.ra_count += (int)(pg_fraction ? PAGE_SIZE - pg_fraction : 0);
}
advise.ra_offset = op->advise_offset;
op->advise_offset += advise.ra_count;
#if defined(__linux__)
_dispatch_io_syscall_switch(err,
readahead(op->fd_entry->fd, advise.ra_offset, (size_t)advise.ra_count),
case EINVAL: break; // fd does refer to a non-supported filetype
default: (void)dispatch_assume_zero(err); break;
);
#else
_dispatch_io_syscall_switch(err,
fcntl(op->fd_entry->fd, F_RDADVISE, &advise),
case EFBIG: break; // advised past the end of the file rdar://10415691
case ENOTSUP: break; // not all FS support radvise rdar://13484629
// TODO: set disk status on error
default: (void)dispatch_assume_zero(err); break;
);
#endif
#endif
}
static int
_dispatch_operation_perform(dispatch_operation_t op)
{
_dispatch_op_debug("perform", op);
int err = _dispatch_io_get_error(op, NULL, true);
if (err) {
goto error;
}
_dispatch_object_debug(op, "%s", __func__);
if (!op->buf) {
size_t max_buf_siz = op->params.high;
size_t chunk_siz = dispatch_io_defaults.chunk_size;
if (op->direction == DOP_DIR_READ) {
// If necessary, create a buffer for the ongoing operation, large
// enough to fit chunk_size but at most high-water
size_t data_siz = dispatch_data_get_size(op->data);
if (data_siz) {
dispatch_assert(data_siz < max_buf_siz);
max_buf_siz -= data_siz;
}
if (max_buf_siz > chunk_siz) {
max_buf_siz = chunk_siz;
}
if (op->length < SIZE_MAX) {
op->buf_siz = op->length - op->total;
if (op->buf_siz > max_buf_siz) {
op->buf_siz = max_buf_siz;
}
} else {
op->buf_siz = max_buf_siz;
}
#if defined(_WIN32)
static bool bQueried = false;
static SYSTEM_INFO siInfo;
if (!bQueried) {
GetNativeSystemInfo(&siInfo);
bQueried = true;
}
op->buf = _aligned_malloc(op->buf_siz, siInfo.dwPageSize);
#else
op->buf = valloc(op->buf_siz);
#endif
_dispatch_op_debug("buffer allocated", op);
} else if (op->direction == DOP_DIR_WRITE) {
// Always write the first data piece, if that is smaller than a
// chunk, accumulate further data pieces until chunk size is reached
if (chunk_siz > max_buf_siz) {
chunk_siz = max_buf_siz;
}
op->buf_siz = 0;
dispatch_data_apply(op->data,
^(dispatch_data_t region DISPATCH_UNUSED,
size_t offset DISPATCH_UNUSED,
const void* buf DISPATCH_UNUSED, size_t len) {
size_t siz = op->buf_siz + len;
if (!op->buf_siz || siz <= chunk_siz) {
op->buf_siz = siz;
}
return (bool)(siz < chunk_siz);
});
if (op->buf_siz > max_buf_siz) {
op->buf_siz = max_buf_siz;
}
dispatch_data_t d;
d = dispatch_data_create_subrange(op->data, 0, op->buf_siz);
op->buf_data = dispatch_data_create_map(d, (const void**)&op->buf,
NULL);
_dispatch_io_data_release(d);
_dispatch_op_debug("buffer mapped", op);
}
}
if (op->fd_entry->fd == -1) {
err = _dispatch_fd_entry_open(op->fd_entry, op->channel);
if (err) {
goto error;
}
}
void *buf = op->buf + op->buf_len;
size_t len = op->buf_siz - op->buf_len;
#if defined(_WIN32)
assert(len <= UINT_MAX && "overflow for read/write");
LONGLONG off = (LONGLONG)((size_t)op->offset + op->total);
#else
off_t off = (off_t)((size_t)op->offset + op->total);
#endif
#if defined(_WIN32)
long processed = -1;
#else
ssize_t processed = -1;
#endif
syscall:
if (op->direction == DOP_DIR_READ) {
if (op->params.type == DISPATCH_IO_STREAM) {
#if defined(_WIN32)
ReadFile((HANDLE)op->fd_entry->fd, buf, (DWORD)len, (LPDWORD)&processed, NULL);
#else
processed = read(op->fd_entry->fd, buf, len);
#endif
} else if (op->params.type == DISPATCH_IO_RANDOM) {
#if defined(_WIN32)
OVERLAPPED ovlOverlapped = {};
ovlOverlapped.Offset = off & 0xffffffff;
ovlOverlapped.OffsetHigh = (off >> 32) & 0xffffffff;
ReadFile((HANDLE)op->fd_entry->fd, buf, (DWORD)len, (LPDWORD)&processed, &ovlOverlapped);
#else
processed = pread(op->fd_entry->fd, buf, len, off);
#endif
}
} else if (op->direction == DOP_DIR_WRITE) {
if (op->params.type == DISPATCH_IO_STREAM) {
#if defined(_WIN32)
WriteFile((HANDLE)op->fd_entry->fd, buf, (DWORD)len, (LPDWORD)&processed, NULL);
#else
processed = write(op->fd_entry->fd, buf, len);
#endif
} else if (op->params.type == DISPATCH_IO_RANDOM) {
#if defined(_WIN32)
OVERLAPPED ovlOverlapped = {};
ovlOverlapped.Offset = off & 0xffffffff;
ovlOverlapped.OffsetHigh = (off >> 32) & 0xffffffff;
WriteFile((HANDLE)op->fd_entry->fd, buf, (DWORD)len, (LPDWORD)&processed, &ovlOverlapped);
#else
processed = pwrite(op->fd_entry->fd, buf, len, off);
#endif
}
}
// Encountered an error on the file descriptor
if (processed == -1) {
err = errno;
if (err == EINTR) {
goto syscall;
}
goto error;
}
// EOF is indicated by two handler invocations
if (processed == 0) {
_dispatch_op_debug("performed: EOF", op);
return DISPATCH_OP_DELIVER_AND_COMPLETE;
}
op->buf_len += (size_t)processed;
op->total += (size_t)processed;
if (op->total == op->length) {
// Finished processing all the bytes requested by the operation
return DISPATCH_OP_COMPLETE;
} else {
// Deliver data only if we satisfy the filters
return DISPATCH_OP_DELIVER;
}
error:
if (err == EAGAIN || err == EWOULDBLOCK) {
// For disk based files with blocking I/O we should never get EAGAIN
dispatch_assert(!op->fd_entry->disk);
_dispatch_op_debug("performed: EAGAIN/EWOULDBLOCK", op);
if (op->direction == DOP_DIR_READ && op->total &&
op->channel == op->fd_entry->convenience_channel) {
// Convenience read with available data completes on EAGAIN
return DISPATCH_OP_COMPLETE_RESUME;
}
return DISPATCH_OP_RESUME;
}
_dispatch_op_debug("performed: err %d", op, err);
op->err = err;
switch (err) {
case ECANCELED:
return DISPATCH_OP_ERR;
case EBADF:
(void)os_atomic_cmpxchg2o(op->fd_entry, err, 0, err, relaxed);
return DISPATCH_OP_FD_ERR;
default:
return DISPATCH_OP_COMPLETE;
}
}
static void
_dispatch_operation_deliver_data(dispatch_operation_t op,
dispatch_op_flags_t flags)
{
// Either called from stream resp. pick queue or when op is finalized
dispatch_data_t data = NULL;
int err = 0;
size_t undelivered = op->undelivered + op->buf_len;
bool deliver = (flags & (DOP_DELIVER|DOP_DONE)) ||
(op->flags & DOP_DELIVER);
op->flags = DOP_DEFAULT;
if (!deliver) {
// Don't deliver data until low water mark has been reached
if (undelivered >= op->params.low) {
deliver = true;
} else if (op->buf_len < op->buf_siz) {
// Request buffer is not yet used up
_dispatch_op_debug("buffer data: undelivered %zu", op, undelivered);
return;
}
} else {
err = op->err;
if (!err && (op->channel->atomic_flags & DIO_STOPPED)) {
err = ECANCELED;
op->err = err;
}
}
// Deliver data or buffer used up
if (op->direction == DOP_DIR_READ) {
if (op->buf_len) {
void *buf = op->buf;
data = dispatch_data_create(buf, op->buf_len, NULL,
DISPATCH_DATA_DESTRUCTOR_FREE);
op->buf = NULL;
op->buf_len = 0;
dispatch_data_t d = dispatch_data_create_concat(op->data, data);
_dispatch_io_data_release(op->data);
_dispatch_io_data_release(data);
data = d;
} else {
data = op->data;
}
op->data = deliver ? dispatch_data_empty : data;
} else if (op->direction == DOP_DIR_WRITE) {
if (deliver) {
data = dispatch_data_create_subrange(op->data, op->buf_len,
op->length);
}
if (op->buf_data && op->buf_len == op->buf_siz) {
_dispatch_io_data_release(op->buf_data);
op->buf_data = NULL;
op->buf = NULL;
op->buf_len = 0;
// Trim newly written buffer from head of unwritten data
dispatch_data_t d;
if (deliver) {
_dispatch_io_data_retain(data);
d = data;
} else {
d = dispatch_data_create_subrange(op->data, op->buf_siz,
op->length);
}
_dispatch_io_data_release(op->data);
op->data = d;
}
} else {
dispatch_assert(op->direction < DOP_DIR_MAX);
return;
}
if (!deliver || ((flags & DOP_NO_EMPTY) && !dispatch_data_get_size(data))) {
op->undelivered = undelivered;
_dispatch_op_debug("buffer data: undelivered %zu", op, undelivered);
return;
}
op->undelivered = 0;
_dispatch_object_debug(op, "%s", __func__);
_dispatch_op_debug("deliver data", op);
dispatch_op_direction_t direction = op->direction;
dispatch_io_handler_t handler = op->handler;
dispatch_fd_entry_t fd_entry = op->fd_entry;
_dispatch_fd_entry_retain(fd_entry);
dispatch_io_t channel = op->channel;
_dispatch_retain(channel);
// Note that data delivery may occur after the operation is freed
dispatch_async(op->op_q, ^{
bool done = (flags & DOP_DONE);
dispatch_data_t d = data;
if (done) {
if (direction == DOP_DIR_READ && err) {
if (dispatch_data_get_size(d)) {
_dispatch_op_debug("IO handler invoke", op);
handler(false, d, 0);
}
d = NULL;
} else if (direction == DOP_DIR_WRITE && !err) {
d = NULL;
}
}
_dispatch_op_debug("IO handler invoke: err %d", op, err);
handler(done, d, err);
_dispatch_release(channel);
_dispatch_fd_entry_release(fd_entry);
_dispatch_io_data_release(data);
});
}
#pragma mark -
#pragma mark dispatch_io_debug
static size_t
_dispatch_io_debug_attr(dispatch_io_t channel, char* buf, size_t bufsiz)
{
dispatch_queue_t target = channel->do_targetq;
return dsnprintf(buf, bufsiz, "type = %s, fd = 0x%x, %sfd_entry = %p, "
"queue = %p, target = %s[%p], barrier_queue = %p, barrier_group = "
"%p, err = 0x%x, low = 0x%zx, high = 0x%zx, interval%s = %llu ",
channel->params.type == DISPATCH_IO_STREAM ? "stream" : "random",
channel->fd_actual, channel->atomic_flags & DIO_STOPPED ?
"stopped, " : channel->atomic_flags & DIO_CLOSED ? "closed, " : "",
channel->fd_entry, channel->queue, target && target->dq_label ?
target->dq_label : "", target, channel->barrier_queue,
channel->barrier_group, channel->err, channel->params.low,
channel->params.high, channel->params.interval_flags &
DISPATCH_IO_STRICT_INTERVAL ? "(strict)" : "",
(unsigned long long) channel->params.interval);
}
size_t
_dispatch_io_debug(dispatch_io_t channel, char* buf, size_t bufsiz)
{
size_t offset = 0;
offset += dsnprintf(&buf[offset], bufsiz - offset, "%s[%p] = { ",
dx_kind(channel), channel);
offset += _dispatch_object_debug_attr(channel, &buf[offset],
bufsiz - offset);
offset += _dispatch_io_debug_attr(channel, &buf[offset], bufsiz - offset);
offset += dsnprintf(&buf[offset], bufsiz - offset, "}");
return offset;
}
static size_t
_dispatch_operation_debug_attr(dispatch_operation_t op, char* buf,
size_t bufsiz)
{
dispatch_queue_t target = op->do_targetq;
dispatch_queue_t oqtarget = op->op_q ? op->op_q->do_targetq : NULL;
return dsnprintf(buf, bufsiz, "type = %s %s, fd = 0x%x, fd_entry = %p, "
"channel = %p, queue = %p -> %s[%p], target = %s[%p], "
"offset = %lld, length = %zu, done = %zu, undelivered = %zu, "
"flags = %u, err = 0x%x, low = 0x%zx, high = 0x%zx, "
"interval%s = %llu ", op->params.type == DISPATCH_IO_STREAM ?
"stream" : "random", op->direction == DOP_DIR_READ ? "read" :
"write", op->fd_entry ? op->fd_entry->fd : -1, op->fd_entry,
op->channel, op->op_q, oqtarget && oqtarget->dq_label ?
oqtarget->dq_label : "", oqtarget, target && target->dq_label ?
target->dq_label : "", target, (long long)op->offset, op->length,
op->total, op->undelivered + op->buf_len, op->flags, op->err,
op->params.low, op->params.high, op->params.interval_flags &
DISPATCH_IO_STRICT_INTERVAL ? "(strict)" : "",
(unsigned long long)op->params.interval);
}