On Fri, Dec 26, 2025 at 06:19:26PM -0300, Fabiano Rosas wrote:
> The migrate_uri_parse function is responsible for converting the URI
> string into a MigrationChannel for consumption by the rest of the
> code. Move it to channel.c and add a wrapper that calls both URI and
> channels parsing.
> 
> While here, add some words about the memory management of the
> MigrationChannel object, which is slightly different from
> migrate_uri_parse() and migrate_channels_parse(). The former takes a
> string and has to allocate a MigrationChannel, the latter takes a QAPI
> object that is managed by the QAPI code.
> 
> Signed-off-by: Fabiano Rosas <[email protected]>

There're some comments added into migration_connect(), that I still don't
think I fully agree upon.. but the rest looks all good to me.

That's probably to be discussed separately anyway, I think you can take
mine here:

Reviewed-by: Peter Xu <[email protected]>

> ---
>  migration/channel.c   | 97 +++++++++++++++++++++++++++++++++++++++++--
>  migration/channel.h   |  9 ++--
>  migration/migration.c | 95 ++----------------------------------------
>  3 files changed, 101 insertions(+), 100 deletions(-)
> 
> diff --git a/migration/channel.c b/migration/channel.c
> index 8b43c3d983..d30e29c9b3 100644
> --- a/migration/channel.c
> +++ b/migration/channel.c
> @@ -40,6 +40,12 @@ bool migration_connect(MigrationAddress *addr, bool out, 
> Error **errp)
>      SocketAddress *saddr;
>      ERRP_GUARD();
>  
> +    /*
> +     * This is reached from a QMP command, the transport code below
> +     * must copy the relevant parts of 'addr' before this function
> +     * returns because the QAPI code will free it.
> +     */
> +
>      switch (addr->transport) {
>      case MIGRATION_ADDRESS_TYPE_SOCKET:
>          saddr = &addr->u.socket;
> @@ -318,10 +324,10 @@ int migration_channel_read_peek(QIOChannel *ioc,
>      return 0;
>  }
>  
> -bool migrate_channels_parse(MigrationChannelList *channels,
> -                            MigrationChannel **main_channelp,
> -                            MigrationChannel **cpr_channelp,
> -                            Error **errp)
> +static bool migrate_channels_parse(MigrationChannelList *channels,
> +                                   MigrationChannel **main_channelp,
> +                                   MigrationChannel **cpr_channelp,
> +                                   Error **errp)
>  {
>      MigrationChannel *channelv[MIGRATION_CHANNEL_TYPE__MAX] = { NULL };
>      bool single_channel;
> @@ -353,6 +359,15 @@ bool migrate_channels_parse(MigrationChannelList 
> *channels,
>          }
>      }
>  
> +    /*
> +     * These don't technically need to be cloned because they come
> +     * from a QAPI object ('channels'). The top-level caller
> +     * (qmp_migrate) needs to copy the necessary information before
> +     * returning from the QMP command. Cloning here is just to keep
> +     * the interface consistent with migrate_uri_parse() that _does
> +     * not_ take a QAPI object and instead allocates and transfers
> +     * ownership of a MigrationChannel to qmp_migrate.
> +     */
>      if (cpr_channelp) {
>          *cpr_channelp = QAPI_CLONE(MigrationChannel,
>                                     channelv[MIGRATION_CHANNEL_TYPE_CPR]);
> @@ -368,3 +383,77 @@ bool migrate_channels_parse(MigrationChannelList 
> *channels,
>  
>      return true;
>  }
> +
> +bool migrate_uri_parse(const char *uri, MigrationChannel **channel,
> +                       Error **errp)
> +{
> +    g_autoptr(MigrationChannel) val = g_new0(MigrationChannel, 1);
> +    g_autoptr(MigrationAddress) addr = g_new0(MigrationAddress, 1);
> +    InetSocketAddress *isock = &addr->u.rdma;
> +    strList **tail = &addr->u.exec.args;
> +
> +    if (strstart(uri, "exec:", NULL)) {
> +        addr->transport = MIGRATION_ADDRESS_TYPE_EXEC;
> +#ifdef WIN32
> +        QAPI_LIST_APPEND(tail, g_strdup(exec_get_cmd_path()));
> +        QAPI_LIST_APPEND(tail, g_strdup("/c"));
> +#else
> +        QAPI_LIST_APPEND(tail, g_strdup("/bin/sh"));
> +        QAPI_LIST_APPEND(tail, g_strdup("-c"));
> +#endif
> +        QAPI_LIST_APPEND(tail, g_strdup(uri + strlen("exec:")));
> +    } else if (strstart(uri, "rdma:", NULL)) {
> +        if (inet_parse(isock, uri + strlen("rdma:"), errp)) {
> +            qapi_free_InetSocketAddress(isock);
> +            return false;
> +        }
> +        addr->transport = MIGRATION_ADDRESS_TYPE_RDMA;
> +    } else if (strstart(uri, "tcp:", NULL) ||
> +                strstart(uri, "unix:", NULL) ||
> +                strstart(uri, "vsock:", NULL) ||
> +                strstart(uri, "fd:", NULL)) {
> +        addr->transport = MIGRATION_ADDRESS_TYPE_SOCKET;
> +        SocketAddress *saddr = socket_parse(uri, errp);
> +        if (!saddr) {
> +            return false;
> +        }
> +        addr->u.socket.type = saddr->type;
> +        addr->u.socket.u = saddr->u;
> +        /* Don't free the objects inside; their ownership moved to "addr" */
> +        g_free(saddr);
> +    } else if (strstart(uri, "file:", NULL)) {
> +        addr->transport = MIGRATION_ADDRESS_TYPE_FILE;
> +        addr->u.file.filename = g_strdup(uri + strlen("file:"));
> +        if (file_parse_offset(addr->u.file.filename, &addr->u.file.offset,
> +                              errp)) {
> +            return false;
> +        }
> +    } else {
> +        error_setg(errp, "unknown migration protocol: %s", uri);
> +        return false;
> +    }
> +
> +    val->channel_type = MIGRATION_CHANNEL_TYPE_MAIN;
> +    val->addr = g_steal_pointer(&addr);
> +    *channel = g_steal_pointer(&val);
> +    return true;
> +}
> +
> +bool migration_channel_parse_input(const char *uri,
> +                                   MigrationChannelList *channels,
> +                                   MigrationChannel **main_channelp,
> +                                   MigrationChannel **cpr_channelp,
> +                                   Error **errp)
> +{
> +    if (!uri == !channels) {
> +        error_setg(errp, "need either 'uri' or 'channels' argument");
> +        return false;
> +    }
> +
> +    if (channels) {
> +        return migrate_channels_parse(channels, main_channelp, cpr_channelp,
> +                                      errp);
> +    } else {
> +        return migrate_uri_parse(uri, main_channelp, errp);
> +    }
> +}
> diff --git a/migration/channel.h b/migration/channel.h
> index b3276550b7..3724b0493a 100644
> --- a/migration/channel.h
> +++ b/migration/channel.h
> @@ -52,8 +52,9 @@ static inline bool 
> migration_connect_incoming(MigrationAddress *addr,
>      return migration_connect(addr, false, errp);
>  }
>  
> -bool migrate_channels_parse(MigrationChannelList *channels,
> -                            MigrationChannel **main_channelp,
> -                            MigrationChannel **cpr_channelp,
> -                            Error **errp);
> +bool migration_channel_parse_input(const char *uri,
> +                                   MigrationChannelList *channels,
> +                                   MigrationChannel **main_channelp,
> +                                   MigrationChannel **cpr_channelp,
> +                                   Error **errp);
>  #endif
> diff --git a/migration/migration.c b/migration/migration.c
> index 6064f1e5ea..15d8459a81 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -15,7 +15,6 @@
>  
>  #include "qemu/osdep.h"
>  #include "qemu/ctype.h"
> -#include "qemu/cutils.h"
>  #include "qemu/error-report.h"
>  #include "qemu/main-loop.h"
>  #include "migration/blocker.h"
> @@ -659,61 +658,6 @@ bool migrate_is_uri(const char *uri)
>      return *uri == ':';
>  }
>  
> -bool migrate_uri_parse(const char *uri, MigrationChannel **channel,
> -                       Error **errp)
> -{
> -    g_autoptr(MigrationChannel) val = g_new0(MigrationChannel, 1);
> -    g_autoptr(MigrationAddress) addr = g_new0(MigrationAddress, 1);
> -    InetSocketAddress *isock = &addr->u.rdma;
> -    strList **tail = &addr->u.exec.args;
> -
> -    if (strstart(uri, "exec:", NULL)) {
> -        addr->transport = MIGRATION_ADDRESS_TYPE_EXEC;
> -#ifdef WIN32
> -        QAPI_LIST_APPEND(tail, g_strdup(exec_get_cmd_path()));
> -        QAPI_LIST_APPEND(tail, g_strdup("/c"));
> -#else
> -        QAPI_LIST_APPEND(tail, g_strdup("/bin/sh"));
> -        QAPI_LIST_APPEND(tail, g_strdup("-c"));
> -#endif
> -        QAPI_LIST_APPEND(tail, g_strdup(uri + strlen("exec:")));
> -    } else if (strstart(uri, "rdma:", NULL)) {
> -        if (inet_parse(isock, uri + strlen("rdma:"), errp)) {
> -            qapi_free_InetSocketAddress(isock);
> -            return false;
> -        }
> -        addr->transport = MIGRATION_ADDRESS_TYPE_RDMA;
> -    } else if (strstart(uri, "tcp:", NULL) ||
> -                strstart(uri, "unix:", NULL) ||
> -                strstart(uri, "vsock:", NULL) ||
> -                strstart(uri, "fd:", NULL)) {
> -        addr->transport = MIGRATION_ADDRESS_TYPE_SOCKET;
> -        SocketAddress *saddr = socket_parse(uri, errp);
> -        if (!saddr) {
> -            return false;
> -        }
> -        addr->u.socket.type = saddr->type;
> -        addr->u.socket.u = saddr->u;
> -        /* Don't free the objects inside; their ownership moved to "addr" */
> -        g_free(saddr);
> -    } else if (strstart(uri, "file:", NULL)) {
> -        addr->transport = MIGRATION_ADDRESS_TYPE_FILE;
> -        addr->u.file.filename = g_strdup(uri + strlen("file:"));
> -        if (file_parse_offset(addr->u.file.filename, &addr->u.file.offset,
> -                              errp)) {
> -            return false;
> -        }
> -    } else {
> -        error_setg(errp, "unknown migration protocol: %s", uri);
> -        return false;
> -    }
> -
> -    val->channel_type = MIGRATION_CHANNEL_TYPE_MAIN;
> -    val->addr = g_steal_pointer(&addr);
> -    *channel = g_steal_pointer(&val);
> -    return true;
> -}
> -
>  static bool
>  migration_incoming_state_setup(MigrationIncomingState *mis, Error **errp)
>  {
> @@ -744,27 +688,10 @@ static void qemu_setup_incoming_migration(const char 
> *uri, bool has_channels,
>      g_autoptr(MigrationChannel) main_ch = NULL;
>      MigrationIncomingState *mis = migration_incoming_get_current();
>  
> -    /*
> -     * Having preliminary checks for uri and channel
> -     */
> -    if (!uri == !channels) {
> -        error_setg(errp, "need either 'uri' or 'channels' argument");
> +    if (!migration_channel_parse_input(uri, channels, &main_ch, NULL, errp)) 
> {
>          return;
>      }
>  
> -    if (channels) {
> -        if (!migrate_channels_parse(channels, &main_ch, NULL, errp)) {
> -            return;
> -        }
> -    }
> -
> -    if (uri) {
> -        /* caller uses the old URI syntax */
> -        if (!migrate_uri_parse(uri, &main_ch, errp)) {
> -            return;
> -        }
> -    }
> -
>      /* transport mechanism not suitable for migration? */
>      if (!migration_transport_compatible(main_ch->addr, errp)) {
>          return;
> @@ -2124,27 +2051,11 @@ void qmp_migrate(const char *uri, bool has_channels,
>      g_autoptr(MigrationChannel) main_ch = NULL;
>      g_autoptr(MigrationChannel) cpr_ch = NULL;
>  
> -    /*
> -     * Having preliminary checks for uri and channel
> -     */
> -    if (!uri == !channels) {
> -        error_setg(errp, "need either 'uri' or 'channels' argument");
> +    if (!migration_channel_parse_input(uri, channels, &main_ch, &cpr_ch,
> +                                       errp)) {
>          return;
>      }
>  
> -    if (channels) {
> -        if (!migrate_channels_parse(channels, &main_ch, &cpr_ch, errp)) {
> -            return;
> -        }
> -    }
> -
> -    if (uri) {
> -        /* caller uses the old URI syntax */
> -        if (!migrate_uri_parse(uri, &main_ch, errp)) {
> -            return;
> -        }
> -    }
> -
>      /* transport mechanism not suitable for migration? */
>      if (!migration_transport_compatible(main_ch->addr, errp)) {
>          return;
> -- 
> 2.51.0
> 

-- 
Peter Xu


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