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libvirt/src/libvirt-stream.c
Michal Privoznik dd75e2e464 virStreamInData: Allow callback to not rewind the stream 
So far, virStreamInData() is effectively a wrapper over
virFDStreamInData() which means it deals with files which can be
rewound (lseek()-ed) to whatever position we need. And in fact,
that's what virFDStreamInData() does - it makes sure that the FD
is left unchanged in terms of position in the file.  Skipping the
hole happens soon after - in daemonStreamHandleRead() when
virStreamSendHole() is called.

But this is about to change. Soon we will have another implementation
where we won't be dealing with FDs but virNetMessage queue and it will
be handy to pop message at the beginning of the queue. Implement and
document this new behavior.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
2021-12-13 14:49:02 +01:00

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/*
* libvirt-stream.c: entry points for virStreamPtr APIs
*
* Copyright (C) 2006-2014 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/>.
*/
#include <config.h>
#include "datatypes.h"
#include "viralloc.h"
#include "virlog.h"
#include "rpc/virnetprotocol.h"
VIR_LOG_INIT("libvirt.stream");
#define VIR_FROM_THIS VIR_FROM_STREAMS
/**
* virStreamNew:
* @conn: pointer to the connection
* @flags: bitwise-OR of virStreamFlags
*
* Creates a new stream object which can be used to perform
* streamed I/O with other public API function.
*
* When no longer needed, a stream object must be released
* with virStreamFree. If a data stream has been used,
* then the application must call virStreamFinish or
* virStreamAbort before free'ing to, in order to notify
* the driver of termination.
*
* If a non-blocking data stream is required passed
* VIR_STREAM_NONBLOCK for flags, otherwise pass 0.
*
* Returns the new stream, or NULL upon error
*/
virStreamPtr
virStreamNew(virConnectPtr conn,
unsigned int flags)
{
virStreamPtr st;
VIR_DEBUG("conn=%p, flags=0x%x", conn, flags);
virResetLastError();
virCheckConnectReturn(conn, NULL);
st = virGetStream(conn);
if (st)
st->flags = flags;
else
virDispatchError(conn);
return st;
}
/**
* virStreamRef:
* @stream: pointer to the stream
*
* Increment the reference count on the stream. For each
* additional call to this method, there shall be a corresponding
* call to virStreamFree to release the reference count, once
* the caller no longer needs the reference to this object.
*
* Returns 0 in case of success, -1 in case of failure
*/
int
virStreamRef(virStreamPtr stream)
{
VIR_DEBUG("stream=%p", stream);
virResetLastError();
virCheckStreamReturn(stream, -1);
virObjectRef(stream);
return 0;
}
/**
* virStreamSend:
* @stream: pointer to the stream object
* @data: buffer to write to stream
* @nbytes: size of @data buffer
*
* Write a series of bytes to the stream. This method may
* block the calling application for an arbitrary amount
* of time. Once an application has finished sending data
* it should call virStreamFinish to wait for successful
* confirmation from the driver, or detect any error.
*
* This method may not be used if a stream source has been
* registered.
*
* Errors are not guaranteed to be reported synchronously
* with the call, but may instead be delayed until a
* subsequent call.
*
* An example using this with a hypothetical file upload
* API looks like
*
* virStreamPtr st = virStreamNew(conn, 0);
* int fd = open("demo.iso", O_RDONLY);
*
* virConnectUploadFile(conn, "demo.iso", st);
*
* while (1) {
* char buf[1024];
* int got = read(fd, buf, 1024);
* if (got < 0) {
* virStreamAbort(st);
* break;
* }
* if (got == 0) {
* virStreamFinish(st);
* break;
* }
* int offset = 0;
* while (offset < got) {
* int sent = virStreamSend(st, buf+offset, got-offset);
* if (sent < 0) {
* virStreamAbort(st);
* goto done;
* }
* offset += sent;
* }
* }
* if (virStreamFinish(st) < 0)
* ... report an error ....
* done:
* virStreamFree(st);
* close(fd);
*
* Returns the number of bytes written, which may be less
* than requested.
*
* Returns -1 upon error, at which time the stream will
* be marked as aborted, and the caller should now release
* the stream with virStreamFree.
*
* Returns -2 if the outgoing transmit buffers are full &
* the stream is marked as non-blocking.
*/
int
virStreamSend(virStreamPtr stream,
const char *data,
size_t nbytes)
{
VIR_DEBUG("stream=%p, data=%p, nbytes=%zi", stream, data, nbytes);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(data, error);
if (stream->driver &&
stream->driver->streamSend) {
int ret;
ret = (stream->driver->streamSend)(stream, data, nbytes);
if (ret == -2)
return -2;
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamRecv:
* @stream: pointer to the stream object
* @data: buffer to read into from stream
* @nbytes: size of @data buffer
*
* Reads a series of bytes from the stream. This method may
* block the calling application for an arbitrary amount
* of time.
*
* Errors are not guaranteed to be reported synchronously
* with the call, but may instead be delayed until a
* subsequent call.
*
* An example using this with a hypothetical file download
* API looks like
*
* virStreamPtr st = virStreamNew(conn, 0);
* int fd = open("demo.iso", O_WRONLY, 0600);
*
* virConnectDownloadFile(conn, "demo.iso", st);
*
* while (1) {
* char buf[1024];
* int got = virStreamRecv(st, buf, 1024);
* if (got < 0) {
* virStreamAbort(st);
* break;
* }
* if (got == 0) {
* virStreamFinish(st);
* break;
* }
* int offset = 0;
* while (offset < got) {
* int sent = write(fd, buf + offset, got - offset);
* if (sent < 0) {
* virStreamAbort(st);
* goto done;
* }
* offset += sent;
* }
* }
* if (virStreamFinish(st) < 0)
* ... report an error ....
* done:
* virStreamFree(st);
* close(fd);
*
*
* Returns the number of bytes read, which may be less
* than requested.
*
* Returns 0 when the end of the stream is reached, at
* which time the caller should invoke virStreamFinish()
* to get confirmation of stream completion.
*
* Returns -1 upon error, at which time the stream will
* be marked as aborted, and the caller should now release
* the stream with virStreamFree.
*
* Returns -2 if there is no data pending to be read & the
* stream is marked as non-blocking.
*/
int
virStreamRecv(virStreamPtr stream,
char *data,
size_t nbytes)
{
VIR_DEBUG("stream=%p, data=%p, nbytes=%zi", stream, data, nbytes);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(data, error);
if (stream->driver &&
stream->driver->streamRecv) {
int ret;
ret = (stream->driver->streamRecv)(stream, data, nbytes);
if (ret == -2)
return -2;
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamRecvFlags:
* @stream: pointer to the stream object
* @data: buffer to read into from stream
* @nbytes: size of @data buffer
* @flags: bitwise-OR of virStreamRecvFlagsValues
*
* Reads a series of bytes from the stream. This method may
* block the calling application for an arbitrary amount
* of time.
*
* This is just like virStreamRecv except this one has extra
* @flags. Calling this function with no @flags set (equal to
* zero) is equivalent to calling virStreamRecv(stream, data, nbytes).
*
* If flag VIR_STREAM_RECV_STOP_AT_HOLE is set, this function
* will stop reading from stream if it has reached a hole. In
* that case, -3 is returned and virStreamRecvHole() should be
* called to get the hole size. An example using this flag might
* look like this:
*
* while (1) {
* char buf[4096];
*
* int ret = virStreamRecvFlags(st, buf, len, VIR_STREAM_STOP_AT_HOLE);
* if (ret < 0) {
* if (ret == -3) {
* long long len;
* ret = virStreamRecvHole(st, &len, 0);
* if (ret < 0) {
* ...error..
* } else {
* ...seek len bytes in target...
* }
* } else {
* return -1;
* }
* } else {
* ...write buf to target...
* }
* }
*
* Returns 0 when the end of the stream is reached, at
* which time the caller should invoke virStreamFinish()
* to get confirmation of stream completion.
*
* Returns -1 upon error, at which time the stream will
* be marked as aborted, and the caller should now release
* the stream with virStreamFree.
*
* Returns -2 if there is no data pending to be read & the
* stream is marked as non-blocking.
*
* Returns -3 if there is a hole in stream and caller requested
* to stop at a hole.
*/
int
virStreamRecvFlags(virStreamPtr stream,
char *data,
size_t nbytes,
unsigned int flags)
{
VIR_DEBUG("stream=%p, data=%p, nbytes=%zu flags=0x%x",
stream, data, nbytes, flags);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(data, error);
if (stream->driver &&
stream->driver->streamRecvFlags) {
int ret;
ret = (stream->driver->streamRecvFlags)(stream, data, nbytes, flags);
if (ret == -2)
return -2;
if (ret == -3)
return -3;
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamSendHole:
* @stream: pointer to the stream object
* @length: number of bytes to skip
* @flags: extra flags; not used yet, so callers should always pass 0
*
* Rather than transmitting empty file space, this API directs
* the @stream target to create @length bytes of empty space.
* This API would be used when uploading or downloading sparsely
* populated files to avoid the needless copy of empty file
* space.
*
* An example using this with a hypothetical file upload API
* looks like:
*
* virStream st;
*
* while (1) {
* char buf[4096];
* size_t len;
* if (..in hole...) {
* ..get hole size...
* virStreamSendHole(st, len, 0);
* } else {
* ...read len bytes...
* virStreamSend(st, buf, len);
* }
* }
*
* Returns 0 on success,
* -1 error
*/
int
virStreamSendHole(virStreamPtr stream,
long long length,
unsigned int flags)
{
VIR_DEBUG("stream=%p, length=%lld flags=0x%x",
stream, length, flags);
virResetLastError();
virCheckStreamReturn(stream, -1);
if (stream->driver &&
stream->driver->streamSendHole) {
int ret;
ret = (stream->driver->streamSendHole)(stream, length, flags);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamRecvHole:
* @stream: pointer to the stream object
* @length: number of bytes to skip
* @flags: extra flags; not used yet, so callers should always pass 0
*
* This API is used to determine the @length in bytes of the
* empty space to be created in a @stream's target file when
* uploading or downloading sparsely populated files. This is the
* counterpart to virStreamSendHole().
*
* Returns 0 on success,
* -1 on error or when there's currently no hole in the stream
*/
int
virStreamRecvHole(virStreamPtr stream,
long long *length,
unsigned int flags)
{
VIR_DEBUG("stream=%p, length=%p flags=0x%x",
stream, length, flags);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgReturn(length, -1);
if (stream->driver &&
stream->driver->streamRecvHole) {
int ret;
ret = (stream->driver->streamRecvHole)(stream, length, flags);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamInData:
* @stream: stream
* @data: are we in data or hole
* @length: length to next section
*
* This function checks the underlying stream (typically a file)
* to learn whether the current stream position lies within a
* data section or a hole. Upon return @data is set to a nonzero
* value if former is the case, or to zero if @stream is in a
* hole. Moreover, @length is updated to tell caller how many
* bytes can be read from @stream until current section changes
* (from data to a hole or vice versa).
*
* NB: there's an implicit hole at EOF. In this situation this
* function should set @data = false, @length = 0 and return 0.
*
* To sum it up:
*
* data section: @data = true, @length > 0
* hole: @data = false, @length > 0
* EOF: @data = false, @length = 0
*
* The position in the underlying stream should not be changed
* upon return from this function, e.g. position in the
* underlying file is kept the same. For streams where this
* condition is impossible to meet, the function can return 1 to
* signal this to a caller.
*
* Returns 0 on success (stream position unchanged),
* 1 on success (stream position changed),
* -1 otherwise
*/
int
virStreamInData(virStreamPtr stream,
int *data,
long long *length)
{
VIR_DEBUG("stream=%p, data=%p, length=%p", stream, data, length);
virResetLastError();
virCheckNonNullArgReturn(data, -1);
virCheckNonNullArgReturn(length, -1);
if (stream->driver->streamInData)
return (stream->driver->streamInData)(stream, data, length);
virReportUnsupportedError();
return -1;
}
/**
* virStreamSendAll:
* @stream: pointer to the stream object
* @handler: source callback for reading data from application
* @opaque: application defined data
*
* Send the entire data stream, reading the data from the
* requested data source. This is simply a convenient alternative
* to virStreamSend, for apps that do blocking-I/O.
*
* An example using this with a hypothetical file upload
* API looks like
*
* int mysource(virStreamPtr st, char *buf, int nbytes, void *opaque) {
* int *fd = opaque;
*
* return read(*fd, buf, nbytes);
* }
*
* virStreamPtr st = virStreamNew(conn, 0);
* int fd = open("demo.iso", O_RDONLY);
*
* virConnectUploadFile(conn, st);
* if (virStreamSendAll(st, mysource, &fd) < 0) {
* ...report an error ...
* goto done;
* }
* if (virStreamFinish(st) < 0)
* ...report an error...
* virStreamFree(st);
* close(fd);
*
* Returns 0 if all the data was successfully sent. The caller
* should invoke virStreamFinish(st) to flush the stream upon
* success and then virStreamFree
*
* Returns -1 upon any error, with virStreamAbort() already
* having been called, so the caller need only call
* virStreamFree().
*/
int
virStreamSendAll(virStreamPtr stream,
virStreamSourceFunc handler,
void *opaque)
{
g_autofree char *bytes = NULL;
size_t want = VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX;
int ret = -1;
VIR_DEBUG("stream=%p, handler=%p, opaque=%p", stream, handler, opaque);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(handler, cleanup);
if (stream->flags & VIR_STREAM_NONBLOCK) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("data sources cannot be used for non-blocking streams"));
goto cleanup;
}
bytes = g_new0(char, want);
errno = 0;
for (;;) {
int got, offset = 0;
got = (handler)(stream, bytes, want, opaque);
if (got < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s", _("send handler failed"));
goto cleanup;
}
if (got == 0)
break;
while (offset < got) {
int done;
done = virStreamSend(stream, bytes + offset, got - offset);
if (done < 0)
goto cleanup;
offset += done;
}
}
ret = 0;
cleanup:
if (ret != 0) {
virErrorPtr orig_err;
virErrorPreserveLast(&orig_err);
virStreamAbort(stream);
virErrorRestore(&orig_err);
virDispatchError(stream->conn);
}
return ret;
}
/**
* virStreamSparseSendAll:
* @stream: pointer to the stream object
* @handler: source callback for reading data from application
* @holeHandler: source callback for determining holes
* @skipHandler: skip holes as reported by @holeHandler
* @opaque: application defined data
*
* Send the entire data stream, reading the data from the
* requested data source. This is simply a convenient alternative
* to virStreamSend, for apps that do blocking-I/O.
*
* An example using this with a hypothetical file upload
* API looks like
*
* int mysource(virStreamPtr st, char *buf, int nbytes, void *opaque) {
* int *fd = opaque;
*
* return read(*fd, buf, nbytes);
* }
*
* int myskip(virStreamPtr st, long long offset, void *opaque) {
* int *fd = opaque;
*
* return lseek(*fd, offset, SEEK_CUR) == (off_t) -1 ? -1 : 0;
* }
*
* int myindata(virStreamPtr st, int *inData,
* long long *offset, void *opaque) {
* int *fd = opaque;
*
* if (@fd in hole) {
* *inData = 0;
* *offset = holeSize;
* } else {
* *inData = 1;
* *offset = dataSize;
* }
*
* return 0;
* }
*
* virStreamPtr st = virStreamNew(conn, 0);
* int fd = open("demo.iso", O_RDONLY);
*
* virConnectUploadSparseFile(conn, st);
* if (virStreamSparseSendAll(st,
* mysource,
* myindata,
* myskip,
* &fd) < 0) {
* ...report an error ...
* goto done;
* }
* if (virStreamFinish(st) < 0)
* ...report an error...
* virStreamFree(st);
* close(fd);
*
* Note that @opaque data are shared between @handler, @holeHandler and @skipHandler.
*
* Returns 0 if all the data was successfully sent. The caller
* should invoke virStreamFinish(st) to flush the stream upon
* success and then virStreamFree.
*
* Returns -1 upon any error, with virStreamAbort() already
* having been called, so the caller need only call
* virStreamFree().
*/
int virStreamSparseSendAll(virStreamPtr stream,
virStreamSourceFunc handler,
virStreamSourceHoleFunc holeHandler,
virStreamSourceSkipFunc skipHandler,
void *opaque)
{
g_autofree char *bytes = NULL;
size_t bufLen = VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX;
int ret = -1;
unsigned long long dataLen = 0;
VIR_DEBUG("stream=%p handler=%p holeHandler=%p opaque=%p",
stream, handler, holeHandler, opaque);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(handler, cleanup);
virCheckNonNullArgGoto(holeHandler, cleanup);
virCheckNonNullArgGoto(skipHandler, cleanup);
if (stream->flags & VIR_STREAM_NONBLOCK) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("data sources cannot be used for non-blocking streams"));
goto cleanup;
}
bytes = g_new0(char, bufLen);
errno = 0;
for (;;) {
int inData, got, offset = 0;
long long sectionLen;
size_t want = bufLen;
const unsigned int skipFlags = 0;
if (!dataLen) {
if (holeHandler(stream, &inData, &sectionLen, opaque) < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s", _("send holeHandler failed"));
goto cleanup;
}
if (!inData && sectionLen) {
if (virStreamSendHole(stream, sectionLen, skipFlags) < 0)
goto cleanup;
if (skipHandler(stream, sectionLen, opaque) < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s",
_("send skipHandler failed"));
goto cleanup;
}
continue;
} else {
dataLen = sectionLen;
}
}
if (want > dataLen)
want = dataLen;
got = (handler)(stream, bytes, want, opaque);
if (got < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s",
_("send handler failed"));
goto cleanup;
}
if (got == 0)
break;
while (offset < got) {
int done;
done = virStreamSend(stream, bytes + offset, got - offset);
if (done < 0)
goto cleanup;
offset += done;
dataLen -= done;
}
}
ret = 0;
cleanup:
if (ret != 0) {
virErrorPtr orig_err;
virErrorPreserveLast(&orig_err);
virStreamAbort(stream);
virErrorRestore(&orig_err);
virDispatchError(stream->conn);
}
return ret;
}
/**
* virStreamRecvAll:
* @stream: pointer to the stream object
* @handler: sink callback for writing data to application
* @opaque: application defined data
*
* Receive the entire data stream, sending the data to the
* requested data sink. This is simply a convenient alternative
* to virStreamRecv, for apps that do blocking-I/O.
*
* An example using this with a hypothetical file download
* API looks like
*
* int mysink(virStreamPtr st, const char *buf, int nbytes, void *opaque) {
* int *fd = opaque;
*
* return write(*fd, buf, nbytes);
* }
*
* virStreamPtr st = virStreamNew(conn, 0);
* int fd = open("demo.iso", O_WRONLY);
*
* virConnectUploadFile(conn, st);
* if (virStreamRecvAll(st, mysink, &fd) < 0) {
* ...report an error ...
* goto done;
* }
* if (virStreamFinish(st) < 0)
* ...report an error...
* virStreamFree(st);
* close(fd);
*
* Returns 0 if all the data was successfully received. The caller
* should invoke virStreamFinish(st) to flush the stream upon
* success and then virStreamFree
*
* Returns -1 upon any error, with virStreamAbort() already
* having been called, so the caller need only call
* virStreamFree()
*/
int
virStreamRecvAll(virStreamPtr stream,
virStreamSinkFunc handler,
void *opaque)
{
g_autofree char *bytes = NULL;
size_t want = VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX;
int ret = -1;
VIR_DEBUG("stream=%p, handler=%p, opaque=%p", stream, handler, opaque);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(handler, cleanup);
if (stream->flags & VIR_STREAM_NONBLOCK) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("data sinks cannot be used for non-blocking streams"));
goto cleanup;
}
bytes = g_new0(char, want);
errno = 0;
for (;;) {
int got, offset = 0;
got = virStreamRecv(stream, bytes, want);
if (got < 0)
goto cleanup;
if (got == 0)
break;
while (offset < got) {
int done;
done = (handler)(stream, bytes + offset, got - offset, opaque);
if (done < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s",
_("recv handler failed"));
goto cleanup;
}
offset += done;
}
}
ret = 0;
cleanup:
if (ret != 0) {
virErrorPtr orig_err;
virErrorPreserveLast(&orig_err);
virStreamAbort(stream);
virErrorRestore(&orig_err);
virDispatchError(stream->conn);
}
return ret;
}
/**
* virStreamSparseRecvAll:
* @stream: pointer to the stream object
* @handler: sink callback for writing data to application
* @holeHandler: stream hole callback for skipping holes
* @opaque: application defined data
*
* Receive the entire data stream, sending the data to the
* requested data sink @handler and calling the skip @holeHandler
* to generate holes for sparse stream targets. This is simply a
* convenient alternative to virStreamRecvFlags, for apps that do
* blocking-I/O.
*
* An example using this with a hypothetical file download
* API looks like:
*
* int mysink(virStreamPtr st, const char *buf, int nbytes, void *opaque) {
* int *fd = opaque;
*
* return write(*fd, buf, nbytes);
* }
*
* int myskip(virStreamPtr st, long long offset, void *opaque) {
* int *fd = opaque;
*
* return lseek(*fd, offset, SEEK_CUR) == (off_t) -1 ? -1 : 0;
* }
*
* virStreamPtr st = virStreamNew(conn, 0);
* int fd = open("demo.iso", O_WRONLY);
*
* virConnectDownloadSparseFile(conn, st);
* if (virStreamSparseRecvAll(st, mysink, myskip, &fd) < 0) {
* ...report an error ...
* goto done;
* }
* if (virStreamFinish(st) < 0)
* ...report an error...
* virStreamFree(st);
* close(fd);
*
* Note that @opaque data is shared between both @handler and
* @holeHandler callbacks.
*
* Returns 0 if all the data was successfully received. The caller
* should invoke virStreamFinish(st) to flush the stream upon
* success and then virStreamFree(st).
*
* Returns -1 upon any error, with virStreamAbort() already
* having been called, so the caller need only call virStreamFree().
*/
int
virStreamSparseRecvAll(virStreamPtr stream,
virStreamSinkFunc handler,
virStreamSinkHoleFunc holeHandler,
void *opaque)
{
g_autofree char *bytes = NULL;
size_t want = VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX;
const unsigned int flags = VIR_STREAM_RECV_STOP_AT_HOLE;
int ret = -1;
VIR_DEBUG("stream=%p handler=%p holeHandler=%p opaque=%p",
stream, handler, holeHandler, opaque);
virResetLastError();
virCheckStreamReturn(stream, -1);
virCheckNonNullArgGoto(handler, cleanup);
virCheckNonNullArgGoto(holeHandler, cleanup);
if (stream->flags & VIR_STREAM_NONBLOCK) {
virReportError(VIR_ERR_OPERATION_INVALID, "%s",
_("data sinks cannot be used for non-blocking streams"));
goto cleanup;
}
bytes = g_new0(char, want);
errno = 0;
for (;;) {
int got, offset = 0;
long long holeLen;
const unsigned int holeFlags = 0;
got = virStreamRecvFlags(stream, bytes, want, flags);
if (got == -3) {
if (virStreamRecvHole(stream, &holeLen, holeFlags) < 0)
goto cleanup;
if (holeHandler(stream, holeLen, opaque) < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s", _("recv holeHandler failed"));
goto cleanup;
}
continue;
} else if (got < 0) {
goto cleanup;
} else if (got == 0) {
break;
}
while (offset < got) {
int done;
done = (handler)(stream, bytes + offset, got - offset, opaque);
if (done < 0) {
if (errno == 0)
errno = EIO;
virReportSystemError(errno, "%s", _("recv handler failed"));
goto cleanup;
}
offset += done;
}
}
ret = 0;
cleanup:
if (ret != 0) {
virErrorPtr orig_err;
virErrorPreserveLast(&orig_err);
virStreamAbort(stream);
virErrorRestore(&orig_err);
virDispatchError(stream->conn);
}
return ret;
}
/**
* virStreamEventAddCallback:
* @stream: pointer to the stream object
* @events: set of events to monitor
* @cb: callback to invoke when an event occurs
* @opaque: application defined data
* @ff: callback to free @opaque data
*
* Register a callback to be notified when a stream
* becomes writable, or readable. This is most commonly
* used in conjunction with non-blocking data streams
* to integrate into an event loop
*
* Returns 0 on success, -1 upon error
*/
int
virStreamEventAddCallback(virStreamPtr stream,
int events,
virStreamEventCallback cb,
void *opaque,
virFreeCallback ff)
{
VIR_DEBUG("stream=%p, events=%d, cb=%p, opaque=%p, ff=%p",
stream, events, cb, opaque, ff);
virResetLastError();
virCheckStreamReturn(stream, -1);
if (stream->driver &&
stream->driver->streamEventAddCallback) {
int ret;
ret = (stream->driver->streamEventAddCallback)(stream, events, cb, opaque, ff);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamEventUpdateCallback:
* @stream: pointer to the stream object
* @events: set of events to monitor
*
* Changes the set of events to monitor for a stream. This allows
* for event notification to be changed without having to
* unregister & register the callback completely. This method
* is guaranteed to succeed if a callback is already registered
*
* Returns 0 on success, -1 if no callback is registered
*/
int
virStreamEventUpdateCallback(virStreamPtr stream,
int events)
{
VIR_DEBUG("stream=%p, events=%d", stream, events);
virResetLastError();
virCheckStreamReturn(stream, -1);
if (stream->driver &&
stream->driver->streamEventUpdateCallback) {
int ret;
ret = (stream->driver->streamEventUpdateCallback)(stream, events);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamEventRemoveCallback:
* @stream: pointer to the stream object
*
* Remove an event callback from the stream
*
* Returns 0 on success, -1 on error
*/
int
virStreamEventRemoveCallback(virStreamPtr stream)
{
VIR_DEBUG("stream=%p", stream);
virResetLastError();
virCheckStreamReturn(stream, -1);
if (stream->driver &&
stream->driver->streamEventRemoveCallback) {
int ret;
ret = (stream->driver->streamEventRemoveCallback)(stream);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamFinish:
* @stream: pointer to the stream object
*
* Indicate that there is no further data to be transmitted
* on the stream. For output streams this should be called once
* all data has been written. For input streams this should be
* called once virStreamRecv returns end-of-file.
*
* This method is a synchronization point for all asynchronous
* errors, so if this returns a success code the application can
* be sure that all data has been successfully processed.
*
* If the stream is non-blocking, any callback must be removed
* beforehand.
*
* Returns 0 on success, -1 upon error
*/
int
virStreamFinish(virStreamPtr stream)
{
VIR_DEBUG("stream=%p", stream);
virResetLastError();
virCheckStreamReturn(stream, -1);
if (stream->driver &&
stream->driver->streamFinish) {
int ret;
ret = (stream->driver->streamFinish)(stream);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamAbort:
* @stream: pointer to the stream object
*
* Request that the in progress data transfer be cancelled
* abnormally before the end of the stream has been reached.
* For output streams this can be used to inform the driver
* that the stream is being terminated early. For input
* streams this can be used to inform the driver that it
* should stop sending data.
*
* If the stream is non-blocking, any callback must be removed
* beforehand.
*
* Returns 0 on success, -1 upon error
*/
int
virStreamAbort(virStreamPtr stream)
{
VIR_DEBUG("stream=%p", stream);
virResetLastError();
virCheckStreamReturn(stream, -1);
if (!stream->driver) {
VIR_DEBUG("aborting unused stream");
return 0;
}
if (stream->driver->streamAbort) {
int ret;
ret = (stream->driver->streamAbort)(stream);
if (ret < 0)
goto error;
return ret;
}
virReportUnsupportedError();
error:
virDispatchError(stream->conn);
return -1;
}
/**
* virStreamFree:
* @stream: pointer to the stream object
*
* Decrement the reference count on a stream, releasing
* the stream object if the reference count has hit zero.
*
* There must not be an active data transfer in progress
* when releasing the stream. If a stream needs to be
* disposed of prior to end of stream being reached, then
* the virStreamAbort function should be called first.
*
* Returns 0 upon success, or -1 on error
*/
int
virStreamFree(virStreamPtr stream)
{
VIR_DEBUG("stream=%p", stream);
virResetLastError();
virCheckStreamReturn(stream, -1);
/* XXX Enforce shutdown before free'ing resources ? */
virObjectUnref(stream);
return 0;
}
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