On Wed, Feb 08, 2023 at 09:35:58AM +0000, Het Gala wrote:
> In existing senario, 'migrate' QAPI argument - string uri, is encoded
> twice to extract migration parameters for stream connection. This is
> not a good representation of migration wire protocol as it is a data
> encoding scheme within a data encoding scheme. Qemu should be able to
> directly work with results from QAPI without having to do a second
> level parsing.
> Modified 'migrate' QAPI design supports well defined MigrateChannel
> struct which plays important role in avoiding double encoding
> of uri strings.
>
> qemu_uri_parsing() parses uri string (kept for backward
> compatibility) and populate the MigrateChannel struct parameters.
> Migration code flow for all required migration transport types -
> socket, exec and rdma is modified.
>
> Suggested-by: Daniel P. Berrange <berra...@redhat.com>
> Suggested-by: Manish Mishra <manish.mis...@nutanix.com>
> Suggested-by: Aravind Retnakaran <aravind.retnaka...@nutanix.com>
> Signed-off-by: Het Gala <het.g...@nutanix.com>
> ---
> migration/exec.c | 31 ++++++++++++++++--
> migration/exec.h | 4 ++-
> migration/migration.c | 75 +++++++++++++++++++++++++++++++++++--------
> migration/rdma.c | 30 +++++------------
> migration/rdma.h | 3 +-
> migration/socket.c | 21 ++++--------
> migration/socket.h | 3 +-
> 7 files changed, 110 insertions(+), 57 deletions(-)
>
> diff --git a/migration/exec.c b/migration/exec.c
> index 375d2e1b54..4fa9819792 100644
> --- a/migration/exec.c
> +++ b/migration/exec.c
> @@ -23,14 +23,39 @@
> #include "migration.h"
> #include "io/channel-command.h"
> #include "trace.h"
> +#include "qapi/error.h"
>
>
> -void exec_start_outgoing_migration(MigrationState *s, const char *command,
> Error **errp)
> +void init_exec_array(strList *command, const char *argv[], Error **errp)
> +{
> + int i = 0;
> + strList *lst;
> +
> + for (lst = command; lst ; lst = lst->next) {
> + argv[i++] = lst->value;
> + }
> +
> + /*
> + * Considering exec command always has 3 arguments to execute
> + * a command directly from the bash itself.
> + */
> + if (i > 3) {
> + error_setg(errp, "exec accepts maximum of 3 arguments in the list");
> + return;
> + }
> +
> + argv[i] = NULL;
> + return;
> +}
> +
> +void exec_start_outgoing_migration(MigrationState *s, strList *command,
> + Error **errp)
> {
> QIOChannel *ioc;
> - const char *argv[] = { "/bin/sh", "-c", command, NULL };
> + const char *argv[4];
> + init_exec_array(command, argv, errp);
>
> - trace_migration_exec_outgoing(command);
> + trace_migration_exec_outgoing(argv[2]);
> ioc = QIO_CHANNEL(qio_channel_command_new_spawn(argv,
> O_RDWR,
> errp));
> diff --git a/migration/exec.h b/migration/exec.h
> index b210ffde7a..5b39ba6cbb 100644
> --- a/migration/exec.h
> +++ b/migration/exec.h
> @@ -19,8 +19,10 @@
>
> #ifndef QEMU_MIGRATION_EXEC_H
> #define QEMU_MIGRATION_EXEC_H
> +void init_exec_array(strList *command, const char *argv[], Error **errp);
> +
> void exec_start_incoming_migration(const char *host_port, Error **errp);
>
> -void exec_start_outgoing_migration(MigrationState *s, const char *host_port,
> +void exec_start_outgoing_migration(MigrationState *s, strList *host_port,
> Error **errp);
> #endif
> diff --git a/migration/migration.c b/migration/migration.c
> index f6dd8dbb03..accbf72a18 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -63,6 +63,7 @@
> #include "sysemu/cpus.h"
> #include "yank_functions.h"
> #include "sysemu/qtest.h"
> +#include "qemu/sockets.h"
> #include "ui/qemu-spice.h"
>
> #define MAX_THROTTLE (128 << 20) /* Migration transfer speed
> throttling */
> @@ -489,6 +490,44 @@ void migrate_add_address(SocketAddress *address)
> QAPI_CLONE(SocketAddress, address));
> }
>
> +static bool migrate_uri_parse(const char *uri,
> + MigrateChannel **channel,
> + Error **errp)
> +{
> + Error *local_err = NULL;
> + MigrateChannel *val = g_new0(MigrateChannel, 1);
> + MigrateAddress *addrs = g_new0(MigrateAddress, 1);
> + SocketAddress *saddr = g_new0(SocketAddress, 1);
> + InetSocketAddress *isock = g_new0(InetSocketAddress, 1);
> +
> + if (strstart(uri, "exec:", NULL)) {
> + addrs->transport = MIGRATE_TRANSPORT_EXEC;
> + addrs->u.exec.data = str_split_at_comma(uri + strlen("exec:"));
Huh, what is the purpose of using 'str_split_at_comma' ? The format
of this is "exec:<shell command>", because it is run as:
const char *argv[] = { "/bin/sh", "-c", command, NULL };
we should not be trying to parse the bit after 'exec:' at all,
and certainly not splitting it on commas which makes no sense
for a shell command.
I would have expected something more like this:
strList **tail = &addrs->u.exec.data;
QAPI_LIST_APPEND(tail, g_strdup("/bin/sh"));
QAPI_LIST_APPEND(tail, g_strdup("-c"));
QAPI_LIST_APPEND(tail, g_strdup(uri + strlen("exec:")));
> + addrs = channel->addr;
> + saddr = channel->addr->u.socket.socket_type;
> + if (addrs->transport == MIGRATE_TRANSPORT_SOCKET) {
> + if (saddr->type == SOCKET_ADDRESS_TYPE_INET ||
> + saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
> + saddr->type == SOCKET_ADDRESS_TYPE_VSOCK) {
> + migrate_protocol_allow_multi_channels(true);
> + socket_start_outgoing_migration(s, saddr, &local_err);
> + } else if (saddr->type == SOCKET_ADDRESS_TYPE_FD) {
> + fd_start_outgoing_migration(s, saddr->u.fd.str, &local_err);
This is probably a sign that fd_start_outgoing_migration() should
be folded into the socket_start_outgoing_migration() method, but
that's a separate cleanup from this patch.
> + }
> + #ifdef CONFIG_RDMA
> + } else if (addrs->transport == MIGRATE_TRANSPORT_RDMA) {
> + rdma_start_outgoing_migration(s, addrs->u.rdma.data, &local_err);
> + #endif
> + } else if (addrs->transport == MIGRATE_TRANSPORT_EXEC) {
> + exec_start_outgoing_migration(s, addrs->u.exec.data, &local_err);
> } else {
> if (!(has_resume && resume)) {
> yank_unregister_instance(MIGRATION_YANK_INSTANCE);
With regards,
Daniel
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