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Re: [Qemu-devel] [PATCH v1 09/22] migration: convert unix socket protoco
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v1 09/22] migration: convert unix socket protocol to use QIOChannel |
Date: |
Tue, 2 Feb 2016 18:02:13 +0000 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
* Daniel P. Berrange (address@hidden) wrote:
> Convert the unix socket migration protocol driver to use
> QIOChannel and QEMUFileChannel, instead of plain sockets
> APIs. It can be unconditionally built, since the socket
> impl of QIOChannel will report a suitable error on platforms
> where UNIX sockets are unavailable.
>
> Signed-off-by: Daniel P. Berrange <address@hidden>
> ---
> migration/Makefile.objs | 4 +-
> migration/migration.c | 4 ++
> migration/unix.c | 103
> +++++++++++++++++++++++++++++++-----------------
> 3 files changed, 72 insertions(+), 39 deletions(-)
>
> diff --git a/migration/Makefile.objs b/migration/Makefile.objs
> index b357e2f..a5f8a03 100644
> --- a/migration/Makefile.objs
> +++ b/migration/Makefile.objs
> @@ -1,11 +1,11 @@
> -common-obj-y += migration.o tcp.o
> +common-obj-y += migration.o tcp.o unix.o
> common-obj-y += vmstate.o
> common-obj-y += qemu-file.o qemu-file-buf.o qemu-file-unix.o
> qemu-file-stdio.o
> common-obj-y += qemu-file-channel.o
> common-obj-y += xbzrle.o postcopy-ram.o
>
> common-obj-$(CONFIG_RDMA) += rdma.o
> -common-obj-$(CONFIG_POSIX) += exec.o unix.o fd.o
> +common-obj-$(CONFIG_POSIX) += exec.o fd.o
>
> common-obj-y += block.o
>
> diff --git a/migration/migration.c b/migration/migration.c
> index e921b20..1c5f12e 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -312,8 +312,10 @@ void qemu_start_incoming_migration(const char *uri,
> Error **errp)
> #if !defined(WIN32)
> } else if (strstart(uri, "exec:", &p)) {
> exec_start_incoming_migration(p, errp);
> +#endif
> } else if (strstart(uri, "unix:", &p)) {
> unix_start_incoming_migration(p, errp);
> +#if !defined(WIN32)
> } else if (strstart(uri, "fd:", &p)) {
> fd_start_incoming_migration(p, errp);
> #endif
> @@ -1017,8 +1019,10 @@ void qmp_migrate(const char *uri, bool has_blk, bool
> blk,
> #if !defined(WIN32)
> } else if (strstart(uri, "exec:", &p)) {
> exec_start_outgoing_migration(s, p, &local_err);
> +#endif
> } else if (strstart(uri, "unix:", &p)) {
> unix_start_outgoing_migration(s, p, &local_err);
> +#if !defined(WIN32)
> } else if (strstart(uri, "fd:", &p)) {
> fd_start_outgoing_migration(s, p, &local_err);
> #endif
> diff --git a/migration/unix.c b/migration/unix.c
> index b591813..4674640 100644
> --- a/migration/unix.c
> +++ b/migration/unix.c
> @@ -1,10 +1,11 @@
> /*
> * QEMU live migration via Unix Domain Sockets
> *
> - * Copyright Red Hat, Inc. 2009
> + * Copyright Red Hat, Inc. 2009-2015
year++ ?
> *
> * Authors:
> * Chris Lalancette <address@hidden>
> + * Daniel P. Berrange <address@hidden>
> *
> * This work is licensed under the terms of the GNU GPL, version 2. See
> * the COPYING file in the top-level directory.
> @@ -17,11 +18,9 @@
>
> #include "qemu-common.h"
> #include "qemu/error-report.h"
> -#include "qemu/sockets.h"
> -#include "qemu/main-loop.h"
> #include "migration/migration.h"
> #include "migration/qemu-file.h"
> -#include "block/block.h"
> +#include "io/channel-socket.h"
>
> //#define DEBUG_MIGRATION_UNIX
>
> @@ -33,71 +32,101 @@
> do { } while (0)
> #endif
>
> -static void unix_wait_for_connect(int fd, Error *err, void *opaque)
> +
> +static SocketAddress *unix_build_address(const char *path)
> +{
> + SocketAddress *saddr;
> +
> + saddr = g_new0(SocketAddress, 1);
> + saddr->type = SOCKET_ADDRESS_KIND_UNIX;
> + saddr->u.q_unix = g_new0(UnixSocketAddress, 1);
> + saddr->u.q_unix->path = g_strdup(path);
> +
> + return saddr;
> +}
> +
> +
> +static void unix_outgoing_migration(Object *src,
> + Error *err,
> + gpointer opaque)
> {
> MigrationState *s = opaque;
> + QIOChannel *sioc = QIO_CHANNEL(src);
>
> - if (fd < 0) {
> + if (err) {
> DPRINTF("migrate connect error: %s\n", error_get_pretty(err));
> s->file = NULL;
> migrate_fd_error(s);
> } else {
> DPRINTF("migrate connect success\n");
> - s->file = qemu_fopen_socket(fd, "wb");
> + s->file = qemu_fopen_channel_output(sioc);
> migrate_fd_connect(s);
> }
> + object_unref(src);
> }
>
> +
> void unix_start_outgoing_migration(MigrationState *s, const char *path,
> Error **errp)
> {
> - unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
> + SocketAddress *saddr = unix_build_address(path);
> + QIOChannelSocket *sioc;
> + sioc = qio_channel_socket_new();
> + qio_channel_socket_connect_async(sioc,
> + saddr,
> + unix_outgoing_migration,
> + s,
> + NULL);
> + qapi_free_SocketAddress(saddr);
It took me a bit of digging to see that qio_channel_socket_connect_async
takes a copy of the address; it's not mentioned in channel-socket.h
> }
>
> -static void unix_accept_incoming_migration(void *opaque)
> +
> +static gboolean unix_accept_incoming_migration(QIOChannel *ioc,
> + GIOCondition condition,
> + gpointer opaque)
> {
> - struct sockaddr_un addr;
> - socklen_t addrlen = sizeof(addr);
> - int s = (intptr_t)opaque;
> QEMUFile *f;
> - int c, err;
> -
> - do {
> - c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
> - err = errno;
> - } while (c < 0 && err == EINTR);
> - qemu_set_fd_handler(s, NULL, NULL, NULL);
> - close(s);
> + QIOChannelSocket *cioc;
(not important but...) why is that a cioc not a sioc?
> + Error *err = NULL;
>
> - DPRINTF("accepted migration\n");
> -
> - if (c < 0) {
> + cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
> + &err);
> + if (!cioc) {
> error_report("could not accept migration connection (%s)",
> - strerror(err));
> - return;
> - }
> -
> - f = qemu_fopen_socket(c, "rb");
> - if (f == NULL) {
> - error_report("could not qemu_fopen socket");
> + error_get_pretty(err));
> goto out;
> }
>
> + DPRINTF("accepted migration\n");
Feel free to replace any DPRINTF's by trace_ entries.
> +
> + f = qemu_fopen_channel_input(QIO_CHANNEL(cioc));
> + object_unref(OBJECT(cioc));
> +
> process_incoming_migration(f);
> - return;
>
> out:
> - close(c);
> + /* Close listening socket as its no longer needed */
> + qio_channel_close(ioc, NULL);
> + return FALSE;
> }
>
> +
> void unix_start_incoming_migration(const char *path, Error **errp)
> {
> - int s;
> + SocketAddress *saddr = unix_build_address(path);
> + QIOChannelSocket *listen_ioc;
>
> - s = unix_listen(path, NULL, 0, errp);
> - if (s < 0) {
> + listen_ioc = qio_channel_socket_new();
> + if (qio_channel_socket_listen_sync(listen_ioc, saddr, errp) < 0) {
OK, so for a unix socket I don't think _sync ever blocks, so we're OK.
> + object_unref(OBJECT(listen_ioc));
> + qapi_free_SocketAddress(saddr);
> return;
> }
>
> - qemu_set_fd_handler(s, unix_accept_incoming_migration, NULL,
> - (void *)(intptr_t)s);
> + qio_channel_add_watch(QIO_CHANNEL(listen_ioc),
> + G_IO_IN,
> + unix_accept_incoming_migration,
> + listen_ioc,
> + (GDestroyNotify)object_unref);
> +
> + qapi_free_SocketAddress(saddr);
> }
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> --
> 2.5.0
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH v1 09/22] migration: convert unix socket protocol to use QIOChannel,
Dr. David Alan Gilbert <=