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io.c
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/*
* 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>
#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_uptime(), \
(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%" PRIx64 "]: " 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
LIST_HEAD(dispatch_disk_head_s, dispatch_disk_s);
LIST_HEAD(dispatch_fd_entry_head_s, dispatch_fd_entry_s);
// Global hashtable of dev_t -> disk_s mappings
DISPATCH_STATIC_GLOBAL(struct dispatch_disk_head_s _dispatch_io_devs[DIO_HASH_SIZE]);
DISPATCH_STATIC_GLOBAL(dispatch_queue_t _dispatch_io_devs_lockq);
// Global hashtable of fd -> fd_entry_s mappings
DISPATCH_STATIC_GLOBAL(struct dispatch_fd_entry_head_s _dispatch_io_fds[DIO_HASH_SIZE]);
DISPATCH_STATIC_GLOBAL(dispatch_queue_t _dispatch_io_fds_lockq);
DISPATCH_STATIC_GLOBAL(dispatch_once_t _dispatch_io_init_pred);
static char const * const _dispatch_io_key = "io";
static void
_dispatch_io_queues_init(void *context DISPATCH_UNUSED)
{
_dispatch_io_fds_lockq = dispatch_queue_create(
"com.apple.libdispatch-io.fd_lockq", NULL);
_dispatch_io_devs_lockq = dispatch_queue_create(
"com.apple.libdispatch-io.dev_lockq", NULL);
}
#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,
};
extern struct dispatch_io_defaults_s {
size_t chunk_size, low_water_chunks, max_pending_io_reqs;
bool initial_delivery;
} dispatch_io_defaults;
DISPATCH_GLOBAL_INIT(struct dispatch_io_defaults_s 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);
break;
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_default_queue(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); });
}
#if defined(_WIN32)
#define _is_separator(ch) ((ch) == '/' || (ch) == '\\')
#else
#define _is_separator(ch) ((ch) == '/')
#endif
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) {
return DISPATCH_BAD_INPUT;
}
#if defined(_WIN32)
if (PathIsRelativeA(path)) {
return DISPATCH_BAD_INPUT;
}
#else
if (!_is_separator(*path)) {
return DISPATCH_BAD_INPUT;
}
#endif
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) &&
!_is_separator(*(path_data->path + path_data->pathlen - 1))) {
// Check parent directory
char *c = NULL;
for (ssize_t i = (ssize_t)path_data->pathlen - 1; i >= 0; i--) {
if (_is_separator(path_data->path[i])) {
c = &path_data->path[i];
break;
}
}
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;
);
#if defined(_WIN32)
*c = '\\';
#else
*c = '/';
#endif
}
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_init_pred, NULL,
_dispatch_io_queues_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);
LIST_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_default_queue(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;