> On 16 Jun 2021, at 15:43, Julien Grall <jul...@xen.org> wrote:
>
> From: Julien Grall <jgr...@amazon.com>
>
> Currently, only liveupdate request can be delayed. The request can only
> be performed by a privileged connection (e.g. dom0). So it is fine to
> have no limits.
>
> In a follow-up patch we will want to delay request for unprivileged
> connection as well. So it is best to apply a limit.
>
> For now and for simplicity, only a single request can be delayed
> for a given unprivileged connection.
>
> Take the opportunity to tweak the prototype and provide a way to
> bypass the quota check. This would be useful when the function
> is called from the restore code.
>
> Signed-off-by: Julien Grall <jgr...@amazon.com>
Reviewed-by: Luca Fancellu <luca.fance...@arm.com>
> ---
> tools/xenstore/xenstored_control.c | 2 +-
> tools/xenstore/xenstored_core.c | 11 ++++++++++-
> tools/xenstore/xenstored_core.h | 3 ++-
> 3 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/tools/xenstore/xenstored_control.c
> b/tools/xenstore/xenstored_control.c
> index 7acc2d134f9f..1c24d4869eab 100644
> --- a/tools/xenstore/xenstored_control.c
> +++ b/tools/xenstore/xenstored_control.c
> @@ -737,7 +737,7 @@ static const char *lu_start(const void *ctx, struct
> connection *conn,
> lu_status->timeout = to;
> lu_status->started_at = time(NULL);
>
> - errno = delay_request(conn, conn->in, do_lu_start, NULL);
> + errno = delay_request(conn, conn->in, do_lu_start, NULL, false);
>
> return NULL;
> }
> diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
> index 41b26d7094c8..51d210828922 100644
> --- a/tools/xenstore/xenstored_core.c
> +++ b/tools/xenstore/xenstored_core.c
> @@ -279,10 +279,19 @@ static void call_delayed(struct connection *conn,
> struct delayed_request *req)
> }
>
> int delay_request(struct connection *conn, struct buffered_data *in,
> - bool (*func)(struct delayed_request *), void *data)
> + bool (*func)(struct delayed_request *), void *data,
> + bool no_quota_check)
> {
> struct delayed_request *req;
>
> + /*
> + * Only allow one request can be delayed for an unprivileged
> + * connection.
> + */
> + if (!no_quota_check && domain_is_unprivileged(conn) &&
> + !list_empty(&conn->delayed))
> + return ENOSPC;
> +
> req = talloc(in, struct delayed_request);
> if (!req)
> return ENOMEM;
> diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
> index 89ce155e755b..34839b34f6e9 100644
> --- a/tools/xenstore/xenstored_core.h
> +++ b/tools/xenstore/xenstored_core.h
> @@ -213,7 +213,8 @@ char *get_parent(const void *ctx, const char *node);
>
> /* Delay a request. */
> int delay_request(struct connection *conn, struct buffered_data *in,
> - bool (*func)(struct delayed_request *), void *data);
> + bool (*func)(struct delayed_request *), void *data,
> + bool no_quota_check);
>
> /* Tracing infrastructure. */
> void trace_create(const void *data, const char *type);
> --
> 2.17.1
>
>
