On 22/11/22 2:30 pm, Daniel P. Berrangé wrote:
On Sat, Nov 19, 2022 at 09:36:14AM +0000, manish.mishra wrote:
MSG_PEEK reads from the peek of channel, The data is treated as
unread and the next read shall still return this data. This
support is currently added only for socket class. Extra parameter
'flags' is added to io_readv calls to pass extra read flags like
MSG_PEEK.
Suggested-by: Daniel P. Berrangé <berra...@redhat.com
Signed-off-by: manish.mishra <manish.mis...@nutanix.com>
---
chardev/char-socket.c | 4 +-
include/io/channel.h | 83 +++++++++++++++++++++++++++++
io/channel-buffer.c | 1 +
io/channel-command.c | 1 +
io/channel-file.c | 1 +
io/channel-null.c | 1 +
io/channel-socket.c | 16 +++++-
io/channel-tls.c | 1 +
io/channel-websock.c | 1 +
io/channel.c | 73 +++++++++++++++++++++++--
migration/channel-block.c | 1 +
scsi/qemu-pr-helper.c | 2 +-
tests/qtest/tpm-emu.c | 2 +-
tests/unit/test-io-channel-socket.c | 1 +
util/vhost-user-server.c | 2 +-
15 files changed, 179 insertions(+), 11 deletions(-)
diff --git a/io/channel-socket.c b/io/channel-socket.c
index b76dca9cc1..a06b24766d 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -406,6 +406,8 @@ qio_channel_socket_accept(QIOChannelSocket *ioc,
}
#endif /* WIN32 */
+ qio_channel_set_feature(QIO_CHANNEL(cioc), QIO_CHANNEL_FEATURE_READ_MSG_PEEK);
+
This covers the incoming server side socket.
This also needs to be set in outgoing client side socket in
qio_channel_socket_connect_async
Yes sorry, i considered only current use-case, but as it is generic one both
should be there. Thanks will update it.
@@ -705,7 +718,6 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
}
#endif /* WIN32 */
-
#ifdef QEMU_MSG_ZEROCOPY
static int qio_channel_socket_flush(QIOChannel *ioc,
Error **errp)
Please remove this unrelated whitespace change.
@@ -109,6 +117,37 @@ int qio_channel_readv_all_eof(QIOChannel *ioc,
return qio_channel_readv_full_all_eof(ioc, iov, niov, NULL, NULL, errp);
}
+int qio_channel_readv_peek_all_eof(QIOChannel *ioc,
+ const struct iovec *iov,
+ size_t niov,
+ Error **errp)
+{
+ ssize_t len = 0;
+ ssize_t total = iov_size(iov, niov);
+
+ while (len < total) {
+ len = qio_channel_readv_full(ioc, iov, niov, NULL,
+ NULL, QIO_CHANNEL_READ_FLAG_MSG_PEEK,
errp);
+
+ if (len == QIO_CHANNEL_ERR_BLOCK) {
+ if (qemu_in_coroutine()) {
+ qio_channel_yield(ioc, G_IO_IN);
+ } else {
+ qio_channel_wait(ioc, G_IO_IN);
+ }
+ continue;
+ }
+ if (len == 0) {
+ return 0;
+ }
+ if (len < 0) {
+ return -1;
+ }
+ }
This will busy wait burning CPU where there is a read > 0 and < total.
Daniel, i could use MSG_WAITALL too if that works but then we will lose
opportunity to yield. Or if you have some other idea.
With regards,
Daniel
Thanks
Manish Mishra
