mirror of
https://github.com/xemu-project/xemu.git
synced 2024-11-24 12:09:58 +00:00
20f4aa265e
The GSource object has ability to have a name, which is useful when debugging performance problems with the mainloop event callbacks that take too long. By associating a name with a QIOChannel object, we can then set the name on any GSource associated with the channel. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
529 lines
17 KiB
C
529 lines
17 KiB
C
/*
|
|
* QEMU I/O channels
|
|
*
|
|
* Copyright (c) 2015 Red Hat, Inc.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*/
|
|
|
|
#ifndef QIO_CHANNEL_H
|
|
#define QIO_CHANNEL_H
|
|
|
|
#include "qemu-common.h"
|
|
#include "qom/object.h"
|
|
|
|
#define TYPE_QIO_CHANNEL "qio-channel"
|
|
#define QIO_CHANNEL(obj) \
|
|
OBJECT_CHECK(QIOChannel, (obj), TYPE_QIO_CHANNEL)
|
|
#define QIO_CHANNEL_CLASS(klass) \
|
|
OBJECT_CLASS_CHECK(QIOChannelClass, klass, TYPE_QIO_CHANNEL)
|
|
#define QIO_CHANNEL_GET_CLASS(obj) \
|
|
OBJECT_GET_CLASS(QIOChannelClass, obj, TYPE_QIO_CHANNEL)
|
|
|
|
typedef struct QIOChannel QIOChannel;
|
|
typedef struct QIOChannelClass QIOChannelClass;
|
|
|
|
#define QIO_CHANNEL_ERR_BLOCK -2
|
|
|
|
typedef enum QIOChannelFeature QIOChannelFeature;
|
|
|
|
enum QIOChannelFeature {
|
|
QIO_CHANNEL_FEATURE_FD_PASS,
|
|
QIO_CHANNEL_FEATURE_SHUTDOWN,
|
|
QIO_CHANNEL_FEATURE_LISTEN,
|
|
};
|
|
|
|
|
|
typedef enum QIOChannelShutdown QIOChannelShutdown;
|
|
|
|
enum QIOChannelShutdown {
|
|
QIO_CHANNEL_SHUTDOWN_BOTH,
|
|
QIO_CHANNEL_SHUTDOWN_READ,
|
|
QIO_CHANNEL_SHUTDOWN_WRITE,
|
|
};
|
|
|
|
typedef gboolean (*QIOChannelFunc)(QIOChannel *ioc,
|
|
GIOCondition condition,
|
|
gpointer data);
|
|
|
|
/**
|
|
* QIOChannel:
|
|
*
|
|
* The QIOChannel defines the core API for a generic I/O channel
|
|
* class hierarchy. It is inspired by GIOChannel, but has the
|
|
* following differences
|
|
*
|
|
* - Use QOM to properly support arbitrary subclassing
|
|
* - Support use of iovecs for efficient I/O with multiple blocks
|
|
* - None of the character set translation, binary data exclusively
|
|
* - Direct support for QEMU Error object reporting
|
|
* - File descriptor passing
|
|
*
|
|
* This base class is abstract so cannot be instantiated. There
|
|
* will be subclasses for dealing with sockets, files, and higher
|
|
* level protocols such as TLS, WebSocket, etc.
|
|
*/
|
|
|
|
struct QIOChannel {
|
|
Object parent;
|
|
unsigned int features; /* bitmask of QIOChannelFeatures */
|
|
char *name;
|
|
#ifdef _WIN32
|
|
HANDLE event; /* For use with GSource on Win32 */
|
|
#endif
|
|
};
|
|
|
|
/**
|
|
* QIOChannelClass:
|
|
*
|
|
* This class defines the contract that all subclasses
|
|
* must follow to provide specific channel implementations.
|
|
* The first five callbacks are mandatory to support, others
|
|
* provide additional optional features.
|
|
*
|
|
* Consult the corresponding public API docs for a description
|
|
* of the semantics of each callback
|
|
*/
|
|
struct QIOChannelClass {
|
|
ObjectClass parent;
|
|
|
|
/* Mandatory callbacks */
|
|
ssize_t (*io_writev)(QIOChannel *ioc,
|
|
const struct iovec *iov,
|
|
size_t niov,
|
|
int *fds,
|
|
size_t nfds,
|
|
Error **errp);
|
|
ssize_t (*io_readv)(QIOChannel *ioc,
|
|
const struct iovec *iov,
|
|
size_t niov,
|
|
int **fds,
|
|
size_t *nfds,
|
|
Error **errp);
|
|
int (*io_close)(QIOChannel *ioc,
|
|
Error **errp);
|
|
GSource * (*io_create_watch)(QIOChannel *ioc,
|
|
GIOCondition condition);
|
|
int (*io_set_blocking)(QIOChannel *ioc,
|
|
bool enabled,
|
|
Error **errp);
|
|
|
|
/* Optional callbacks */
|
|
int (*io_shutdown)(QIOChannel *ioc,
|
|
QIOChannelShutdown how,
|
|
Error **errp);
|
|
void (*io_set_cork)(QIOChannel *ioc,
|
|
bool enabled);
|
|
void (*io_set_delay)(QIOChannel *ioc,
|
|
bool enabled);
|
|
off_t (*io_seek)(QIOChannel *ioc,
|
|
off_t offset,
|
|
int whence,
|
|
Error **errp);
|
|
};
|
|
|
|
/* General I/O handling functions */
|
|
|
|
/**
|
|
* qio_channel_has_feature:
|
|
* @ioc: the channel object
|
|
* @feature: the feature to check support of
|
|
*
|
|
* Determine whether the channel implementation supports
|
|
* the optional feature named in @feature.
|
|
*
|
|
* Returns: true if supported, false otherwise.
|
|
*/
|
|
bool qio_channel_has_feature(QIOChannel *ioc,
|
|
QIOChannelFeature feature);
|
|
|
|
/**
|
|
* qio_channel_set_feature:
|
|
* @ioc: the channel object
|
|
* @feature: the feature to set support for
|
|
*
|
|
* Add channel support for the feature named in @feature.
|
|
*/
|
|
void qio_channel_set_feature(QIOChannel *ioc,
|
|
QIOChannelFeature feature);
|
|
|
|
/**
|
|
* qio_channel_set_name:
|
|
* @ioc: the channel object
|
|
* @name: the name of the channel
|
|
*
|
|
* Sets the name of the channel, which serves as an aid
|
|
* to debugging. The name is used when creating GSource
|
|
* watches for this channel.
|
|
*/
|
|
void qio_channel_set_name(QIOChannel *ioc,
|
|
const char *name);
|
|
|
|
/**
|
|
* qio_channel_readv_full:
|
|
* @ioc: the channel object
|
|
* @iov: the array of memory regions to read data into
|
|
* @niov: the length of the @iov array
|
|
* @fds: pointer to an array that will received file handles
|
|
* @nfds: pointer filled with number of elements in @fds on return
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Read data from the IO channel, storing it in the
|
|
* memory regions referenced by @iov. Each element
|
|
* in the @iov will be fully populated with data
|
|
* before the next one is used. The @niov parameter
|
|
* specifies the total number of elements in @iov.
|
|
*
|
|
* It is not required for all @iov to be filled with
|
|
* data. If the channel is in blocking mode, at least
|
|
* one byte of data will be read, but no more is
|
|
* guaranteed. If the channel is non-blocking and no
|
|
* data is available, it will return QIO_CHANNEL_ERR_BLOCK
|
|
*
|
|
* If the channel has passed any file descriptors,
|
|
* the @fds array pointer will be allocated and
|
|
* the elements filled with the received file
|
|
* descriptors. The @nfds pointer will be updated
|
|
* to indicate the size of the @fds array that
|
|
* was allocated. It is the callers responsibility
|
|
* to call close() on each file descriptor and to
|
|
* call g_free() on the array pointer in @fds.
|
|
*
|
|
* It is an error to pass a non-NULL @fds parameter
|
|
* unless qio_channel_has_feature() returns a true
|
|
* value for the QIO_CHANNEL_FEATURE_FD_PASS constant.
|
|
*
|
|
* Returns: the number of bytes read, or -1 on error,
|
|
* or QIO_CHANNEL_ERR_BLOCK if no data is available
|
|
* and the channel is non-blocking
|
|
*/
|
|
ssize_t qio_channel_readv_full(QIOChannel *ioc,
|
|
const struct iovec *iov,
|
|
size_t niov,
|
|
int **fds,
|
|
size_t *nfds,
|
|
Error **errp);
|
|
|
|
|
|
/**
|
|
* qio_channel_writev_full:
|
|
* @ioc: the channel object
|
|
* @iov: the array of memory regions to write data from
|
|
* @niov: the length of the @iov array
|
|
* @fds: an array of file handles to send
|
|
* @nfds: number of file handles in @fds
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Write data to the IO channel, reading it from the
|
|
* memory regions referenced by @iov. Each element
|
|
* in the @iov will be fully sent, before the next
|
|
* one is used. The @niov parameter specifies the
|
|
* total number of elements in @iov.
|
|
*
|
|
* It is not required for all @iov data to be fully
|
|
* sent. If the channel is in blocking mode, at least
|
|
* one byte of data will be sent, but no more is
|
|
* guaranteed. If the channel is non-blocking and no
|
|
* data can be sent, it will return QIO_CHANNEL_ERR_BLOCK
|
|
*
|
|
* If there are file descriptors to send, the @fds
|
|
* array should be non-NULL and provide the handles.
|
|
* All file descriptors will be sent if at least one
|
|
* byte of data was sent.
|
|
*
|
|
* It is an error to pass a non-NULL @fds parameter
|
|
* unless qio_channel_has_feature() returns a true
|
|
* value for the QIO_CHANNEL_FEATURE_FD_PASS constant.
|
|
*
|
|
* Returns: the number of bytes sent, or -1 on error,
|
|
* or QIO_CHANNEL_ERR_BLOCK if no data is can be sent
|
|
* and the channel is non-blocking
|
|
*/
|
|
ssize_t qio_channel_writev_full(QIOChannel *ioc,
|
|
const struct iovec *iov,
|
|
size_t niov,
|
|
int *fds,
|
|
size_t nfds,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_readv:
|
|
* @ioc: the channel object
|
|
* @iov: the array of memory regions to read data into
|
|
* @niov: the length of the @iov array
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Behaves as qio_channel_readv_full() but does not support
|
|
* receiving of file handles.
|
|
*/
|
|
ssize_t qio_channel_readv(QIOChannel *ioc,
|
|
const struct iovec *iov,
|
|
size_t niov,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_writev:
|
|
* @ioc: the channel object
|
|
* @iov: the array of memory regions to write data from
|
|
* @niov: the length of the @iov array
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Behaves as qio_channel_writev_full() but does not support
|
|
* sending of file handles.
|
|
*/
|
|
ssize_t qio_channel_writev(QIOChannel *ioc,
|
|
const struct iovec *iov,
|
|
size_t niov,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_readv:
|
|
* @ioc: the channel object
|
|
* @buf: the memory region to read data into
|
|
* @buflen: the length of @buf
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Behaves as qio_channel_readv_full() but does not support
|
|
* receiving of file handles, and only supports reading into
|
|
* a single memory region.
|
|
*/
|
|
ssize_t qio_channel_read(QIOChannel *ioc,
|
|
char *buf,
|
|
size_t buflen,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_writev:
|
|
* @ioc: the channel object
|
|
* @buf: the memory regions to send data from
|
|
* @buflen: the length of @buf
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Behaves as qio_channel_writev_full() but does not support
|
|
* sending of file handles, and only supports writing from a
|
|
* single memory region.
|
|
*/
|
|
ssize_t qio_channel_write(QIOChannel *ioc,
|
|
const char *buf,
|
|
size_t buflen,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_set_blocking:
|
|
* @ioc: the channel object
|
|
* @enabled: the blocking flag state
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* If @enabled is true, then the channel is put into
|
|
* blocking mode, otherwise it will be non-blocking.
|
|
*
|
|
* In non-blocking mode, read/write operations may
|
|
* return QIO_CHANNEL_ERR_BLOCK if they would otherwise
|
|
* block on I/O
|
|
*/
|
|
int qio_channel_set_blocking(QIOChannel *ioc,
|
|
bool enabled,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_close:
|
|
* @ioc: the channel object
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Close the channel, flushing any pending I/O
|
|
*
|
|
* Returns: 0 on success, -1 on error
|
|
*/
|
|
int qio_channel_close(QIOChannel *ioc,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_shutdown:
|
|
* @ioc: the channel object
|
|
* @how: the direction to shutdown
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Shutdowns transmission and/or receiving of data
|
|
* without closing the underlying transport.
|
|
*
|
|
* Not all implementations will support this facility,
|
|
* so may report an error. To avoid errors, the
|
|
* caller may check for the feature flag
|
|
* QIO_CHANNEL_FEATURE_SHUTDOWN prior to calling
|
|
* this method.
|
|
*
|
|
* Returns: 0 on success, -1 on error
|
|
*/
|
|
int qio_channel_shutdown(QIOChannel *ioc,
|
|
QIOChannelShutdown how,
|
|
Error **errp);
|
|
|
|
/**
|
|
* qio_channel_set_delay:
|
|
* @ioc: the channel object
|
|
* @enabled: the new flag state
|
|
*
|
|
* Controls whether the underlying transport is
|
|
* permitted to delay writes in order to merge
|
|
* small packets. If @enabled is true, then the
|
|
* writes may be delayed in order to opportunistically
|
|
* merge small packets into larger ones. If @enabled
|
|
* is false, writes are dispatched immediately with
|
|
* no delay.
|
|
*
|
|
* When @enabled is false, applications may wish to
|
|
* use the qio_channel_set_cork() method to explicitly
|
|
* control write merging.
|
|
*
|
|
* On channels which are backed by a socket, this
|
|
* API corresponds to the inverse of TCP_NODELAY flag,
|
|
* controlling whether the Nagle algorithm is active.
|
|
*
|
|
* This setting is merely a hint, so implementations are
|
|
* free to ignore this without it being considered an
|
|
* error.
|
|
*/
|
|
void qio_channel_set_delay(QIOChannel *ioc,
|
|
bool enabled);
|
|
|
|
/**
|
|
* qio_channel_set_cork:
|
|
* @ioc: the channel object
|
|
* @enabled: the new flag state
|
|
*
|
|
* Controls whether the underlying transport is
|
|
* permitted to dispatch data that is written.
|
|
* If @enabled is true, then any data written will
|
|
* be queued in local buffers until @enabled is
|
|
* set to false once again.
|
|
*
|
|
* This feature is typically used when the automatic
|
|
* write coalescing facility is disabled via the
|
|
* qio_channel_set_delay() method.
|
|
*
|
|
* On channels which are backed by a socket, this
|
|
* API corresponds to the TCP_CORK flag.
|
|
*
|
|
* This setting is merely a hint, so implementations are
|
|
* free to ignore this without it being considered an
|
|
* error.
|
|
*/
|
|
void qio_channel_set_cork(QIOChannel *ioc,
|
|
bool enabled);
|
|
|
|
|
|
/**
|
|
* qio_channel_seek:
|
|
* @ioc: the channel object
|
|
* @offset: the position to seek to, relative to @whence
|
|
* @whence: one of the (POSIX) SEEK_* constants listed below
|
|
* @errp: pointer to a NULL-initialized error object
|
|
*
|
|
* Moves the current I/O position within the channel
|
|
* @ioc, to be @offset. The value of @offset is
|
|
* interpreted relative to @whence:
|
|
*
|
|
* SEEK_SET - the position is set to @offset bytes
|
|
* SEEK_CUR - the position is moved by @offset bytes
|
|
* SEEK_END - the position is set to end of the file plus @offset bytes
|
|
*
|
|
* Not all implementations will support this facility,
|
|
* so may report an error.
|
|
*
|
|
* Returns: the new position on success, (off_t)-1 on failure
|
|
*/
|
|
off_t qio_channel_io_seek(QIOChannel *ioc,
|
|
off_t offset,
|
|
int whence,
|
|
Error **errp);
|
|
|
|
|
|
/**
|
|
* qio_channel_create_watch:
|
|
* @ioc: the channel object
|
|
* @condition: the I/O condition to monitor
|
|
*
|
|
* Create a new main loop source that is used to watch
|
|
* for the I/O condition @condition. Typically the
|
|
* qio_channel_add_watch() method would be used instead
|
|
* of this, since it directly attaches a callback to
|
|
* the source
|
|
*
|
|
* Returns: the new main loop source.
|
|
*/
|
|
GSource *qio_channel_create_watch(QIOChannel *ioc,
|
|
GIOCondition condition);
|
|
|
|
/**
|
|
* qio_channel_add_watch:
|
|
* @ioc: the channel object
|
|
* @condition: the I/O condition to monitor
|
|
* @func: callback to invoke when the source becomes ready
|
|
* @user_data: opaque data to pass to @func
|
|
* @notify: callback to free @user_data
|
|
*
|
|
* Create a new main loop source that is used to watch
|
|
* for the I/O condition @condition. The callback @func
|
|
* will be registered against the source, to be invoked
|
|
* when the source becomes ready. The optional @user_data
|
|
* will be passed to @func when it is invoked. The @notify
|
|
* callback will be used to free @user_data when the
|
|
* watch is deleted
|
|
*
|
|
* The returned source ID can be used with g_source_remove()
|
|
* to remove and free the source when no longer required.
|
|
* Alternatively the @func callback can return a FALSE
|
|
* value.
|
|
*
|
|
* Returns: the source ID
|
|
*/
|
|
guint qio_channel_add_watch(QIOChannel *ioc,
|
|
GIOCondition condition,
|
|
QIOChannelFunc func,
|
|
gpointer user_data,
|
|
GDestroyNotify notify);
|
|
|
|
|
|
/**
|
|
* qio_channel_yield:
|
|
* @ioc: the channel object
|
|
* @condition: the I/O condition to wait for
|
|
*
|
|
* Yields execution from the current coroutine until
|
|
* the condition indicated by @condition becomes
|
|
* available.
|
|
*
|
|
* This must only be called from coroutine context
|
|
*/
|
|
void qio_channel_yield(QIOChannel *ioc,
|
|
GIOCondition condition);
|
|
|
|
/**
|
|
* qio_channel_wait:
|
|
* @ioc: the channel object
|
|
* @condition: the I/O condition to wait for
|
|
*
|
|
* Block execution from the current thread until
|
|
* the condition indicated by @condition becomes
|
|
* available.
|
|
*
|
|
* This will enter a nested event loop to perform
|
|
* the wait.
|
|
*/
|
|
void qio_channel_wait(QIOChannel *ioc,
|
|
GIOCondition condition);
|
|
|
|
#endif /* QIO_CHANNEL_H */
|