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qemu/include/io/channel.h
Anthony Harivel 95fa0c79a0 qio: add support for SO_PEERCRED for socket channel 
The function qio_channel_get_peercred() returns a pointer to the
credentials of the peer process connected to this socket.

This credentials structure is defined in <sys/socket.h> as follows:

struct ucred {
	pid_t pid;    /* Process ID of the sending process */
	uid_t uid;    /* User ID of the sending process */
	gid_t gid;    /* Group ID of the sending process */
};

The use of this function is possible only for connected AF_UNIX stream
sockets and for AF_UNIX stream and datagram socket pairs.

On platform other than Linux, the function return 0.

Signed-off-by: Anthony Harivel <aharivel@redhat.com>
Link: https://lore.kernel.org/r/20240522153453.1230389-2-aharivel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-07-22 13:47:41 +02:00

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/*
* 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 2.1 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 "qom/object.h"
#include "qemu/coroutine-core.h"
#include "block/aio.h"
#define TYPE_QIO_CHANNEL "qio-channel"
OBJECT_DECLARE_TYPE(QIOChannel, QIOChannelClass,
QIO_CHANNEL)
#define QIO_CHANNEL_ERR_BLOCK -2
#define QIO_CHANNEL_WRITE_FLAG_ZERO_COPY 0x1
#define QIO_CHANNEL_READ_FLAG_MSG_PEEK 0x1
typedef enum QIOChannelFeature QIOChannelFeature;
enum QIOChannelFeature {
QIO_CHANNEL_FEATURE_FD_PASS,
QIO_CHANNEL_FEATURE_SHUTDOWN,
QIO_CHANNEL_FEATURE_LISTEN,
QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY,
QIO_CHANNEL_FEATURE_READ_MSG_PEEK,
QIO_CHANNEL_FEATURE_SEEKABLE,
};
typedef enum QIOChannelShutdown QIOChannelShutdown;
enum QIOChannelShutdown {
QIO_CHANNEL_SHUTDOWN_READ = 1,
QIO_CHANNEL_SHUTDOWN_WRITE = 2,
QIO_CHANNEL_SHUTDOWN_BOTH = 3,
};
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;
AioContext *read_ctx;
Coroutine *read_coroutine;
AioContext *write_ctx;
Coroutine *write_coroutine;
bool follow_coroutine_ctx;
#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. io_shutdown in particular
* must be thread-safe, terminate quickly and must not block.
*/
struct QIOChannelClass {
ObjectClass parent;
/* Mandatory callbacks */
ssize_t (*io_writev)(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds,
size_t nfds,
int flags,
Error **errp);
ssize_t (*io_readv)(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds,
size_t *nfds,
int flags,
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 */
ssize_t (*io_pwritev)(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp);
ssize_t (*io_preadv)(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp);
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);
void (*io_set_aio_fd_handler)(QIOChannel *ioc,
AioContext *read_ctx,
IOHandler *io_read,
AioContext *write_ctx,
IOHandler *io_write,
void *opaque);
int (*io_flush)(QIOChannel *ioc,
Error **errp);
int (*io_peerpid)(QIOChannel *ioc,
unsigned int *pid,
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
* @flags: read flags (QIO_CHANNEL_READ_FLAG_*)
* @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,
int flags,
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
* @flags: write flags (QIO_CHANNEL_WRITE_FLAG_*)
* @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,
int flags,
Error **errp);
/**
* qio_channel_readv_all_eof:
* @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
*
* 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.
*
* The function will wait for all requested data
* to be read, yielding from the current coroutine
* if required.
*
* If end-of-file occurs before any data is read,
* no error is reported; otherwise, if it occurs
* before all requested data has been read, an error
* will be reported.
*
* Returns: 1 if all bytes were read, 0 if end-of-file
* occurs without data, or -1 on error
*/
int coroutine_mixed_fn qio_channel_readv_all_eof(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp);
/**
* qio_channel_readv_all:
* @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
*
* 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.
*
* The function will wait for all requested data
* to be read, yielding from the current coroutine
* if required.
*
* If end-of-file occurs before all requested data
* has been read, an error will be reported.
*
* Returns: 0 if all bytes were read, or -1 on error
*/
int coroutine_mixed_fn qio_channel_readv_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp);
/**
* qio_channel_writev_all:
* @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
*
* 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.
*
* The function will wait for all requested data
* to be written, yielding from the current coroutine
* if required.
*
* Returns: 0 if all bytes were written, or -1 on error
*/
int coroutine_mixed_fn qio_channel_writev_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
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_read:
* @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_write:
* @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_read_all_eof:
* @ioc: the channel object
* @buf: the memory region to read data into
* @buflen: the number of bytes to @buf
* @errp: pointer to a NULL-initialized error object
*
* Reads @buflen bytes into @buf, possibly blocking or (if the
* channel is non-blocking) yielding from the current coroutine
* multiple times until the entire content is read. If end-of-file
* occurs immediately it is not an error, but if it occurs after
* data has been read it will return an error rather than a
* short-read. Otherwise behaves as qio_channel_read().
*
* Returns: 1 if all bytes were read, 0 if end-of-file occurs
* without data, or -1 on error
*/
int coroutine_mixed_fn qio_channel_read_all_eof(QIOChannel *ioc,
char *buf,
size_t buflen,
Error **errp);
/**
* qio_channel_read_all:
* @ioc: the channel object
* @buf: the memory region to read data into
* @buflen: the number of bytes to @buf
* @errp: pointer to a NULL-initialized error object
*
* Reads @buflen bytes into @buf, possibly blocking or (if the
* channel is non-blocking) yielding from the current coroutine
* multiple times until the entire content is read. If end-of-file
* occurs it will return an error rather than a short-read. Otherwise
* behaves as qio_channel_read().
*
* Returns: 0 if all bytes were read, or -1 on error
*/
int coroutine_mixed_fn qio_channel_read_all(QIOChannel *ioc,
char *buf,
size_t buflen,
Error **errp);
/**
* qio_channel_write_all:
* @ioc: the channel object
* @buf: the memory region to write data into
* @buflen: the number of bytes to @buf
* @errp: pointer to a NULL-initialized error object
*
* Writes @buflen bytes from @buf, possibly blocking or (if the
* channel is non-blocking) yielding from the current coroutine
* multiple times until the entire content is written. Otherwise
* behaves as qio_channel_write().
*
* Returns: 0 if all bytes were written, or -1 on error
*/
int coroutine_mixed_fn qio_channel_write_all(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_set_follow_coroutine_ctx:
* @ioc: the channel object
* @enabled: whether or not to follow the coroutine's AioContext
*
* If @enabled is true, calls to qio_channel_yield() use the current
* coroutine's AioContext. Usually this is desirable.
*
* If @enabled is false, calls to qio_channel_yield() use the global iohandler
* AioContext. This is may be used by coroutines that run in the main loop and
* do not wish to respond to I/O during nested event loops. This is the
* default for compatibility with code that is not aware of AioContexts.
*/
void qio_channel_set_follow_coroutine_ctx(QIOChannel *ioc, bool enabled);
/**
* 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_pwritev
* @ioc: the channel object
* @iov: the array of memory regions to write data from
* @niov: the length of the @iov array
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* 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_SEEKABLE prior to calling this method.
*
* Behaves as qio_channel_writev_full, apart from not supporting
* sending of file handles as well as beginning the write at the
* passed @offset
*
*/
ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp);
/**
* qio_channel_pwrite
* @ioc: the channel object
* @buf: the memory region to write data into
* @buflen: the number of bytes to @buf
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* 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_SEEKABLE prior to calling this method.
*
*/
ssize_t qio_channel_pwrite(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp);
/**
* qio_channel_preadv
* @ioc: the channel object
* @iov: the array of memory regions to read data into
* @niov: the length of the @iov array
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* 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_SEEKABLE prior to calling this method.
*
* Behaves as qio_channel_readv_full, apart from not supporting
* receiving of file handles as well as beginning the read at the
* passed @offset
*
*/
ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp);
/**
* qio_channel_pread
* @ioc: the channel object
* @buf: the memory region to write data into
* @buflen: the number of bytes to @buf
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* 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_SEEKABLE prior to calling this method.
*
*/
ssize_t qio_channel_pread(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, 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.
*
* This function is thread-safe, terminates quickly and does not block.
*
* 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_add_watch_full:
* @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
* @context: the context to run the watch source
*
* Similar as qio_channel_add_watch(), but allows to specify context
* to run the watch source.
*
* Returns: the source ID
*/
guint qio_channel_add_watch_full(QIOChannel *ioc,
GIOCondition condition,
QIOChannelFunc func,
gpointer user_data,
GDestroyNotify notify,
GMainContext *context);
/**
* qio_channel_add_watch_source:
* @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
* @context: gcontext to bind the source to
*
* Similar as qio_channel_add_watch(), but allows to specify context
* to run the watch source, meanwhile return the GSource object
* instead of tag ID, with the GSource referenced already.
*
* Note: callers is responsible to unref the source when not needed.
*
* Returns: the source pointer
*/
GSource *qio_channel_add_watch_source(QIOChannel *ioc,
GIOCondition condition,
QIOChannelFunc func,
gpointer user_data,
GDestroyNotify notify,
GMainContext *context);
/**
* 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. @condition must
* be either %G_IO_IN or %G_IO_OUT; it cannot contain both. In
* addition, no two coroutine can be waiting on the same condition
* and channel at the same time.
*
* This must only be called from coroutine context. It is safe to
* reenter the coroutine externally while it is waiting; in this
* case the function will return even if @condition is not yet
* available.
*/
void coroutine_fn qio_channel_yield(QIOChannel *ioc,
GIOCondition condition);
/**
* qio_channel_wake_read:
* @ioc: the channel object
*
* If qio_channel_yield() is currently waiting for the channel to become
* readable, interrupt it and reenter immediately. This function is safe to call
* from any thread.
*/
void qio_channel_wake_read(QIOChannel *ioc);
/**
* 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);
/**
* qio_channel_set_aio_fd_handler:
* @ioc: the channel object
* @read_ctx: the AioContext to set the read handler on or NULL
* @io_read: the read handler
* @write_ctx: the AioContext to set the write handler on or NULL
* @io_write: the write handler
* @opaque: the opaque value passed to the handler
*
* This is used internally by qio_channel_yield(). It can
* be used by channel implementations to forward the handlers
* to another channel (e.g. from #QIOChannelTLS to the
* underlying socket).
*
* When @read_ctx is NULL, don't touch the read handler. When @write_ctx is
* NULL, don't touch the write handler. Note that setting the read handler
* clears the write handler, and vice versa, if they share the same AioContext.
* Therefore the caller must pass both handlers together when sharing the same
* AioContext.
*/
void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
AioContext *read_ctx,
IOHandler *io_read,
AioContext *write_ctx,
IOHandler *io_write,
void *opaque);
/**
* qio_channel_readv_full_all_eof:
* @ioc: the channel object
* @iov: the array of memory regions to read data to
* @niov: the length of the @iov array
* @fds: an array of file handles to read
* @nfds: number of file handles in @fds
* @errp: pointer to a NULL-initialized error object
*
*
* Performs same function as qio_channel_readv_all_eof.
* Additionally, attempts to read file descriptors shared
* over the channel. The function will wait for all
* requested data to be read, yielding from the current
* coroutine if required. data refers to both file
* descriptors and the iovs.
*
* Returns: 1 if all bytes were read, 0 if end-of-file
* occurs without data, or -1 on error
*/
int coroutine_mixed_fn qio_channel_readv_full_all_eof(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds, size_t *nfds,
Error **errp);
/**
* qio_channel_readv_full_all:
* @ioc: the channel object
* @iov: the array of memory regions to read data to
* @niov: the length of the @iov array
* @fds: an array of file handles to read
* @nfds: number of file handles in @fds
* @errp: pointer to a NULL-initialized error object
*
*
* Performs same function as qio_channel_readv_all_eof.
* Additionally, attempts to read file descriptors shared
* over the channel. The function will wait for all
* requested data to be read, yielding from the current
* coroutine if required. data refers to both file
* descriptors and the iovs.
*
* Returns: 0 if all bytes were read, or -1 on error
*/
int coroutine_mixed_fn qio_channel_readv_full_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds, size_t *nfds,
Error **errp);
/**
* qio_channel_writev_full_all:
* @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
* @flags: write flags (QIO_CHANNEL_WRITE_FLAG_*)
* @errp: pointer to a NULL-initialized error object
*
*
* Behaves like qio_channel_writev_full but will attempt
* to send all data passed (file handles and memory regions).
* The function will wait for all requested data
* to be written, yielding from the current coroutine
* if required.
*
* If QIO_CHANNEL_WRITE_FLAG_ZERO_COPY is passed in flags,
* instead of waiting for all requested data to be written,
* this function will wait until it's all queued for writing.
* In this case, if the buffer gets changed between queueing and
* sending, the updated buffer will be sent. If this is not a
* desired behavior, it's suggested to call qio_channel_flush()
* before reusing the buffer.
*
* Returns: 0 if all bytes were written, or -1 on error
*/
int coroutine_mixed_fn qio_channel_writev_full_all(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds, size_t nfds,
int flags, Error **errp);
/**
* qio_channel_flush:
* @ioc: the channel object
* @errp: pointer to a NULL-initialized error object
*
* Will block until every packet queued with
* qio_channel_writev_full() + QIO_CHANNEL_WRITE_FLAG_ZERO_COPY
* is sent, or return in case of any error.
*
* If not implemented, acts as a no-op, and returns 0.
*
* Returns -1 if any error is found,
* 1 if every send failed to use zero copy.
* 0 otherwise.
*/
int qio_channel_flush(QIOChannel *ioc,
Error **errp);
/**
* qio_channel_get_peercred:
* @ioc: the channel object
* @pid: pointer to pid
* @errp: pointer to a NULL-initialized error object
*
* Returns the pid of the peer process connected to this socket.
*
* The use of this function is possible only for connected
* AF_UNIX stream sockets and for AF_UNIX stream and datagram
* socket pairs on Linux.
* Return -1 on error with pid -1 for the non-Linux OS.
*
*/
int qio_channel_get_peerpid(QIOChannel *ioc,
unsigned int *pid,
Error **errp);
#endif /* QIO_CHANNEL_H */
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